Hazardous Waste Management System, Standards for … · waste underground storage tanks that cannot be entered for inspection. Section 3004(o)(4) directs EPA to promulgate standards

Federal Register / Vol. 51, No. 134./ Monday, July 14, 1986 / Rules and Regulations

ENVIRONMENTAL PROTECTIONAGENCY

40 CFR Parts 260, 261, 262, 264, 265,270, and 271

[SWH-FRL-3023-9]

Hazardous Waste ManagementSystem; Standards for HazardousWaste Storage and Treatment TankSystems

AGENCY: Environmental ProtectionAgency.ACTION: Final rule.

SUMMARY: On June 26, 1985, the U.S.Environmental Protection Agency (EPA)proposed regulations that would revisethe existing regulations for the storageand treatment of hazardous waste intank systems under the ResourceConservation and Recovery Act (RCRA)as amended by the Hazardous and SolidWaste Amendments of 1984 (HSWA).The proposed rules represented theAgency's efforts to meet the mandatesof HSWA and to modify certain existingtank regulations that have provedunworkable and/or ineffective. Theover-all goal of this effort is to establishregulations that ensure the protection ofhuman health and the environment fromthe risks posed by releases fromhazardous waste tank systems.

EPA is today promulgating finalregulations for new and existing interimstatus, accumulation, and permittedtank systems. The final rulesubstantially amends the sections of 40CFR Parts 260, 261, 262, 264, 265, 270,and 271 that apply to tank systemsmanaging hazardous wastes. Theseregulations address, among other things,the design and installation of theprimary containment vessel, releasedetection and response, and closure/post-closure requirements.EFFECTIVE DATE: The application ofrevised Parts 260, 261, 262, 264, 265, 270,and 271 will take effect January 12, 1987,except for § 261.4(a)(8) which will takeeffect on July 14, 1986. Small QuantityGenerators who generate between 100and 1000 kg/month of hazardous wasteand accumulate in quantities exceeding6000 kg or accumulate for more than 180days (or for nore than 270 days if thewaste is shipped more than 200 miles)will become subject to revised Parts 264,265, and 270 on March 24, 1987.ADDRESSES: The docket for thisRulemaking (Docket No. 6-86-RTSF-

-PFFFF, Revised Tank SystemsStandards) is located at U.S.Environmental Protection Agency, EPARCRA Docket (Sub-basement), 401 MStreet SW., Washington, DC 20460. The

docket is open from 9:30 a.m. to 3:30p.m., Monday through Friday, except forFederal holidays. The public must makean appointment to review docketmaterials by calling Mia Zmud at (202)475-9327 or Kate Blow at (202) 382-4675.The public may copy a maximum of 50pages of material from any oneregulatory docket at no cost. Additionalcopies cost $0.20 per page.FOR FURTHER INFORMATION CONTACT:For general information contact theRCRA/Superfund Hotline, at (800) 424-3946 (toll free) or (202) 382-3000 inWashington, DC. For information on thespecific technical aspects of this rule,contact: William J. Kline, Office of SolidWaste (WH-565), U.S. EnvironmentalProtection Agency, Washington, DC20460, (202) 382-7917. For specificinformation on the economic analysisand risk assessment for this rulemaking,contact: Betsy Tam, Office of SolidWaste (WH-565), U.S. EnvironmentalProtection Agency, Washington, DC20460, (202) 382-2791.SUPPLEMENTARY INFORMATION: Thecontents to today's preamble are listedbelow:I. AuthorityII. Background

A. Existing Subtitle C Regulations forHazardous Waste Storage and TreatmentTanks

B. Hazardous and Solid WasteAmendments of 1984

C. June 26, 1985 Notice of ProposedRulemaking

D. August 1, 1985 Proposed Rules andMarch 24, 1986-Final Rules Applicable toSmall Quantity Generators

E. March 17, 1986, Notice of AvailabilityF. Court-imposed Deadline for Issuance of

RegulationsG. Summary of Today's Final RuleH. Related Actions

III. Overall Strategy for Regulation ofHazardous Waste Storage and TreatmentTank Systems

A. Proposed Hazardous Waste TankSystem Regulations1. Problems Associated with TankSystems2. General Approach

a. Existing Hazardous Waste TankSystems

b. New Hazardous Waste TankSystems

c. Hazardous Waste AccumulationTank Systems

d. Small Quantity Generators3. Development of Regulatory Approachat Proposal

B. Development of Regulatory Strategy andRequirements for the Final Regulation1. Problems Associated with HazardousWaste Tank Systems2. Causes of Releases from Tank Systems

a. Corrosion* * b. Structural Failure

c.Ancillary Equipment Failured. Operator Errors

3. Risks Posed by Releases fromHazardous Waste Tank Systems4. Technical Options for AddressingProblems Associated with Leaking TankSystems

a. Corrosionb. Structural Failurec. Ancillary Equipment Failured. Operator Errorse. Multiple Causes of Releases

5. Regulatory Approacha. Summary of Approach Taken in

Final Ruleb. Secondary Containment

6. Regulatory Options Not Selecteda. Combination of Secondary

Containment and Ground-WaterMonitoring

b. National Risk-based Standardsc. Minimium National Standards with

a Variance from ContainmentRequirements Based on Risk

d. Minimum Performance Standardse. Ban of Underground Tanksf. Forced Retirement of Underground

Tank SystemsIV. Changes to Final Rule From Proposal

A. Additions1. Definitions

a. Onground Tank Systems.b. Sumpsc. Ancillary Equipment

2. Exclusion of Closed-Loop Recycling.Tank Systems

B. Revisions Made Subsequent to Proposal1. Accumulation Tank Systems (§ 262.34),2. Applicability (§ 264.190 and § 265.190)

a. Storage of Hazardous WasteContaining No Free Liquids

b. Temporary Tank Systems3. Assessment of Existing Tank SystemIntegrity (§ 264.191 and § 265.191)4. Design and Installation of New TankSystems (§ 264.192 and § 265.192)5. Containment and Detection ofReleases (§ 264.193 and § 265.193)

a. General and Specific Requirementsfor Tank Systems

b. Deletion of Ground-waterMonitoring Alternative

c. Leak Testing and Tank SystemIntegrity Assessment Requirements

d. Variances from SecondaryContainment6. General Operating Requirements(§ 264.194 and § 265.194)7. Inspections (§ 264.195, and § 265.195)8. Response to Leaks or Spills andDisposition of Leaking or Unfit-for-UseTank Systems (§ 264 196 and § 265.196)

a. General Responses to Leaks orSpills

b. Disposition of Leaking or Unfit-for-Use Tank Systems9. Closure and Post-Closure Care(§ 264.197 and § 265.197)10. Special Requirements for Ignitableand Reactive Wastes (§ 264.198 and§ 265.198)11. Special Requirements forIncompatible Wastes (§ 264.199 and§ 265.199)12. Waste Analysis and Trial Testo(§ 265.200)

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Federal Register / Vol. 51, No. 134 / Monday, July 14, 1986 / Rules and Regulations

13. Special Requirements for Generatorsof Between 100 and 1,000 kg/mo ThatAccumulate Hazardous Waste in Tanks(§ 265.201)14. Specific Part B InformationRequirements for Tank Systems(§ 270.16]

V. Analysis of Other Significant CommentsA. Corrective Action for Accumulation

Tank SystemsB. Acutely Hazardous WasteC. Small Quantity GeneratorsD. Hazardous Waste Tank Risk AnalysisE. Contingent Post-Closure PlansF. Integrity AssessmentsC. Leak Detection StandardH. Wastewater Piping and Treatment

TanksI. Risks of Double-Walled PipesJ. Closure and Post-Closure RequirementsK. Incentive to Store in DrumsL. SPCC RegulationsM. 24-Hour Detection RequirementN. Future Designated Hazardous Wastes

VI. Relationship to Current RCRA HazardousWaste Programs

A. State Authority1. Applicability of Rules in AuthorizedStates2. Effect on State Authorizations

a. HSWA Provisionsb. Non-HSWA Provisionsc. Program Modification Deadlines

B. Regulation of Underground ProductStorage Tanks (the UST Program)

C. Relationship of Regulation to Section3014(c) of RCRA

VII. Economic AnalysisA. Cost and Economic Impact MethodologyB. Cost and Economic Impacts

VIII. Supporting DocumentsIX. Executive Order 12291X. Paperwork Reduction ActX1. Regulatory Flexibility ActXII. List of Subjects in 40 CFR Parts 260, 261,

262, 264, 265, 270, and 271

I. Authority

These regulations are issued under theauthority of sections 1006, 2002, 3001-3007, 3010, 3014, 3017, 3018, 3019, and7004 of the Solid Waste Disposal Act of1970, as amended by the ResourceConservation and Recovery Act of 1976,as amended (42 U.S.C. 6905, 6912, 6921-6927, 6930, 6934, 6935, 6937, 6938, 6939,and 6974).

II. Background

A. Existing Subtitle C Regulations forHazardous Waste Storage andTreatment Tanks

On October 21, 1976, Congressenacted the Resource Conservation andRecovery Act (RCRA) to protect humanhealth and the environment and toconserve material and energy resources.In Subtitle C of the Act, EPA is directedto promulgate regulations that identifyhazardous waste and to regulategenerators and transporters ofhazardous waste and facilities thattreat, store, or dispose of hazardous

waste. Since enactment of the Act, EPAhas promulgated interim status andpermitting standards governing thedesign, operation, and maintenance of'facilities used to treat, store, or disposeof hazardous wastes, includingstandards for tanks that are used-to,store or treat hazardous waste. •

On May 19, 1980, EPA promulgatedinterim status standards for the storageor treatment of hazardous waste intanks (Part 265, Subpart J 45 FR 33244-33245). These standards, which alsowere applicable to 90-day accumulationtanks, focused on operating measuresdesigned to prevent releases ofhazardous waste from tanks.

On January 12, 1981, the Agencypromulgated the RCRA permittingstandards for those hazardous wastestorage and treatment tanks that can beentered for inspection (46 FR 2867-2868).The regulations were codified as 40 CFRPart 264, Subpart J. These standards,which emphasized the structuralintegrity of storage and treatment tanksto protect against leaks, ruptures, andcollapse of the shell, require adequate

.design, maintenance of minimum shellthickness, and inspections. Concurrentwith the promulgation of thesepermitting standards, EPA requestedpublic comments on numerous issues ofconcern for future rulemaking, includingsecondary containment for allhazardous waste tanks and the possiblebanning of underground hazardouswaste tanks.

EPA did not promulgate requirementsfor secondary containment at that time;however, the Agency explained that itwould continue to consider threesecondary containment options aspossible future requirements forhazardous waste tanks. One of theseoptions was complete secondarycontainment, which would consist of animpervious base underlying the tank(s).Its purpose would be to contain all spillsand leaks completely until they could beremoved.

B. Hazardous and Solid WasteAmendments of 1984

On November 8, 1984, the Hazardousand Solid Waste Amendments of 1984were enacted. Two of theseamendments directly address thestorage and treatment of hazardouswaste in underground tank systems.

Section 3004(w) required EPA topromulgate, by March*1, 1985, finalpermitting standards for hazardouswaste underground storage tanks thatcannot be entered for inspection.Section 3004(o)(4) directs EPA topromulgate standards requiring any newunderground tank system to utilize an"approved leak detection system,"

defined as a system or technologycapable of detecting leaks of hazardousconstituents at the earliest practicabletime.

C. June 26, 1985 Notice of ProposedRulemaking . .: .

EPA issued a Notice of ProposedRulemaking (NPRM), which waspublished in the Federal Register onJune 26, 1985 (50 FR 26444-26504), tosolicit comments on the proposedrevised standards for hazardous wastestorage and treatment tank systems.These revised standards were intendedto satisfy the requirements of sections3004(w) and 3004(o)(4) of the Hazardousand Solid Waste Amendments of 1984,as well as to revise certain existing tankstandards. The proposed rules wouldhave required that owner/operators ofexisting hazardous waste storage andtreatment tank systems installsecondary containment or its equivalentand that new or replacement tanksystems be fitted with secondarycontainment before being placed intoservice. The proposed rules also wouldhave imposed requirements to ensurethe proper installation of tank systems,appropriate corrosion protection, thatowner/operators of tank systemsfollowed procedures for responding toleaks, and that tank systems wereproperly closed, where feasible, withoutallowing contamination to remain insoils adjacent to the tank systems.

D. August 1, 1985 Proposed Rules andMarch 24, 1986 Final Rules Applicableto Small Quantity Generators

Simultaneously with this rulemakingfor RCRA storage and treatment tanksystems, the Agency has beendeveloping regulations applicable tohazardous waste management by 100-1000 kg/mo generators ["small quantitygenerators"). The Agency proposed newwaste management rules for smallquantity generators on August 1, 1985(50 FR 31278). This proposal would haverequired that small quantity generatorswho store wastes in tanks for greaterthan 180 days (or greater than 270 daysif waste must be shipped over 200 miles)or who exceed the 6000 kg accumulationlimit would be subject to Parts 264 and265, as well as the requirement to obtaina RCRA permit. The Agency alsoproposed that the June 1985 proposedrevisions to the hazardous waste tankstandards, if promulgated, would applyto such facilities.

The Agency also proposed to applythe then-existing Subpart J requirementsto small quantity generators who storeup to 6000 kg of hazardous waste for 180days or less (or 270 days or less if the

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waste must be shipped more than 200miles) under § 262.34. Theseaccumulation tanks are exempt frompermitting/interim status requirements.The Agency explained that it had notdetermined whether the proposedamendments to Subpart J requiringsecondary containment for short termaccumulation tanks should be applied togenerators of 100-1000 kg/mo,particularly in light of their potentialimpacts. The Agency stated that itwould make this decision uponcompletion of its assessment of the risksassociated with hazardous wastestorage tank systems and based oncomments received.

The final rule for management ofhazardous wastes for small quantitygenerators was published in the FederalRegister on March 24, 1986, (51 FR10166). The final rule requires smallquantity generators who accumulatehazardous waste on site for greater than180 (or 270) days or exceed the 6000 kglimit to comply with the full Parts 264and 265 requirements. For thosegenerators accumulating up to 6000 kgfor up to 180 (or 270) days under§ 262.34, the existing provisions ofSubpart J, Part 265 would apply. In thepreamble to the final rule, EPA indicatedthat, because it had not yet completedits evaluation of the proposed tanksystem amendments as applied to smallquantity generator accumulation tanksystems (50 FR 26444-26504, June 26,1985), application of any modified tanksystem standards to small quantitygenerators' accumulation tank systemswould be determined in the finalhazardous waste tank system rule (i.e.,today's rule). (See 51 FR 10166; March24, 1986.)

E. March 17, 1986, Notice of Availability

On March 17, 1986, the Agencypublished a Federal Register Notice ofAvailability on the hazardous wastetank risk assessment methodology andpreliminary results (51 FR 9072). The riskanalysis involved the following modelcomponents:

* A Monte Carlo Simulation modelthat predicts failure events andestimates the associated releasevolumes for hazardous waste tanks;

* A subsurface transport andenvironmental fate model that simulatescontaminant transport and degradationin the unsaturated andge a14jy0023saturated zones; and

9 An exposure and risk model thatestimates human exposure to hazardouschemicals via contaminated drinkingwater and calculates health risks to anexposed individual.

In the March 17th Notice ofAvailability, the Agency solicited

comments on the appropriateness of themethodology and on how the Agencyshould consider using the analysis indeveloping or implementing the finalhazardous waste tank systemregulations. In addition, the Agencyrequested comment on the possibility ofmaking distinctions in the regulationsbased on differences in the risksestimated for different tank types.

F. Court-Imposed Deadline for Issuanceof Regulations

As indicated above, section 3004(w) ofthe HSWA of 1984 required the Agencyto promulgate permitting standards forunderground tanks that cannot beentered for inspection by March 1, 1985.The Agency was unable to meet thisdeadline and subsequently was sued bythe Environmental Defense Fund. Inresponse to the Environmental DefenseFund's suit, the United States DistrictCourt for the District of Columbiaordered the Agency to promulgate theregulations required by section 3004(w)no later than June 30, 1986.

C. Summary of Today's Final RuleToday's rule establishes new or

revised tank system standards,including standards applicable toaccumulation tank systems (exceptsmall quantity generator accumulationtank systems), interim status tanksystems, and permitted tank systems.These standards include requirementsfor proper installation of new tanks, leaktesting and detection, corrosionprotection, structural integrity,secondary containment, responses toleaks to the environment, closure andpost-closure care (if required).

This section provides a briefdiscussion of the major requirements oftoday's final rule. One major feature isthe requirement for secondarycontainment with interstitial monitoringfor most hazardous waste tank systems.

Secondary containment withinterstitial monitoring must be providedfor all new hazardous waste tanksystems. For the purpose of today'sregulation, the term "new tank system"means not only newly-manufacturedtank systems that will be put intoservice for the first time but also thoseother tank systems that, even if inexistence and in use prior to thepromulgation date of today'sregulations, are then reinstalled andused as replacement tank systems forexisting hazardous waste tank systems.Likewise, an existing tank system that isnot being used for the storage ortreatment of hazardous waste, but isthen put into service or converted to useas a hazardous waste storage ortreatment tank system subsequent to the

promulgation date of today's regulationis considered to be a new tank system.

For existing tank systems, secondarycontainment with interstitial monitoringwill be phased in. The ground-watermonitoring alternative, which wasproposed as an option for most existingtank systems, will not be allowed. Thereasons for this significant change fromproposal are discussed in section III.B.5of this preamble.

Tanks storing or treating listed dioxin-containing wastes must be providedwith secondary containment within twoyears of the effective date of thisregulation. Other existing tanks that aredetermined to be non-leaking on thebasis of tank integrity assessments orother means must be provided withsecondary containment by the time thetank is 15 years old. Periodic tanksystem integrity assessments arerequired for all tanks not fitted withsecondary containment In the event aleak is discovered (through the tankintegrity assessment or otherwise) inany component of the tank system (i.e.,tank vessel, ancillary equipment) that isunderground, that component of the tanksystem must be provided withsecondary containment before the tanksystem is returned to service.Additionally, if a leak has occurred inany portion of a tank system componentthat is not readily accessible for visualinspection (e.g., the bottom of anonground tank), the entire componentmust be provided with secondarycontainment prior to the tank systembeing returned to service.

The rule provides two variances fromthe secondary containment requirement.The owner/operator of the tank systemcan petition the Regional Administratorfor a variance from the secondarycontainment requirement if he candemonstrate either (a) that alternativedesign or operating practices will detectleaks and prevent the migration of anyhazardous waste beyond a zone ofengineering control (i.e., an area underthe control of the owner/operator that,upon detection of a release, can and willbe readily cleaned up prior to therelease of hazardous constituents toground water or surface waters); or (b)that if a release does occur, there will beno substantial present or potentialhazard to human health or theenvironment. The second variance willnot be available for new undergroundtanks, because section 3004(o)(4) ofRCRA requires that all newunderground tanks have leak detectionsystems.

The reasons for the requirement thatall tank systems that do not qualify for avariance must be provided with

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secondary containment with interstitialmonitoring are explained in section III.Bof this preamble. Briefly, the Agencyconcluded that no other method of leakdetection can be considered generallyreliable for hazardous waste tanksystems. Thus, secondary containmentis the only generally-applicablemechanism that will allow detection andresponse to releases from hazardouswaste tank systems before they reachground water and/or surface water.

Some commenters suggested thatunsaturated zone monitoring andsubsequent corrective action providedan acceptable alternative to secondarycontainment. EPA has not adoptedunsaturated zone monitoring in this finalrule as an acceptable method of releasedetection because the state-of-the-art ofunsaturated zone monitoring is notsufficiently advanced or proven toenable the Agency to allow it as asubstitute for secondary containmentwith interstitial monitoring forhazardous waste tank systems. It ispossible, however, in case-specificsituations, that an owner/operator willbe able to demonstrate that anunsaturated zone monitoring system willfully protect human health and theenvironment from releases fromhazardous waste tank systems and willqualify for a variance from thesecondary containment requirement.EPA is conducting studies of thereliability of unsaturated zonemonitoring and will consider modifyingthese final rules in the future if thesestudies demonstrate that unsaturatedzone monitoring is rellable for thedetection of releases of hazardouswastes from tank systems so thatappropriate response can be taken priorto their reaching ground water orsurface water.

In addition to the requirement forsecondary containment, this final ruleestablishes design and installationstandards for new tank systems. It alsoestablishes inspection, corrosionprotection, and monitoring requirementsas well as various operating controlsand practices designed to prevent spillsand overflows, including the immediateresponse to leaks. Finally, financialassurance, closure, and post-closurerequirements are established.

Except as noted immediately below,today's rule completely replaces the pre-

existing Subpart I of 40 CFR Parts 264and 265.

Effective March 24, 1987, the interimstatus and permitting requirements,including the new Subpart Jrequirements of this final regulation,apply to small quantity generators whostore wastes in tank systems for greaterthan 180 days (or 270 days if theaccumulated waste is shipped over 200miles) or who exceed the 6,000 kg limitof § 262.34(d). This regulation does notapply to new or existing accumulationtank systems owned or operated by 100-1,000 kg/mo generators who store up to6,000 kg of wastes in tank systems forless than 180 (or 270) days. These tanksystems must meet the requirementspreviously imposed by Subpart J in Part265. These requirements appear intoday's rule at § 265.201. However, EPAwill propose, in the near future, in aseparate notice, revised Subpart Jrequirements for all small quantitygenerator hazardous wasteaccumulation tank systems.

Today's final rule does not apply,however, to tank systems that areintegrally tied to reclamation operationsthat are considered part of a closed-loopreclamation process and, hence, notstoring solid and hazardous waste.These circumstances exist whenhazardous secondary materials arereturned, after being reclaimed, to theoriginal process in which they weregenerated, where they are reused in theproduction process, provided that thehazardous materials are notaccumulated over 12 months withoutbeing reclaimed and that thereclamation process does not involvecontrolled flame combustion. Seesection IV.A.2 of today's preamble for amore detailed discussion.

Today's final rule represents arecodification of the various sectionsthat appeared in the proposed rule. Thischange resulted from an analysis ofsuggestions submitted by a number ofcommenters that there be moreconsistency in the regulation of all tanksystems. Responding to this suggestionrequired the development of newsections and the reorganization ofothers. Table 1 shows the changes.

There are some differences in today'srule in the requirements for permitted,interim status, and 90-day accumulationtank systems. Table 2 summarizes the

requirements of today's final rules forthe various types of tank systems.

H. Related ActionsElsewhere in today's Federal Register,

the Agency is addressing an issuerelated to this rulemaking. In a separatenotice, the Agency is solicitingcomments with respect to whether theexemption from permitting requirementsfor 90-day accumulation tank systemsshould be modified or eliminated. If itwere eliminated, 90-day accumulationtank systems would be subject tocorrective action, financial assurance,and other requirements.

Also, in the near future, the Agencywill propose standards applicable toaccumulation tank systems owned oroperated by generators of 100 to 1,000kg/mo who store up to 6,000 kg ofhazardous wastes in tanks for less than180 days (or less than 270 days if thewaste must be shipped over 200 miles).

TABLE 1 .---CHANGES IN CODIFICATION OFPARTS 264 AND 265 STANDARDS

Subject Proposed Final

section section

Part 204

Applicability .............................................. 264.190 264.190Design of tank systems ......................... 264.191 '264.192Installation ............................................... 264.192 '264.192Secondary containment ......................... 264.193 264.193General operating requirements ........... 264.194 264.194Inspections .............................................. 264.195 264.195Response to and disposition of leak-

ing or unfit-for-use tank systems 264.196 264.196Closure and post-closure cave ............ 264.197 264.197Special requirements for ignitible or

reactive wastes .................................. 264.198 264.198Special requirements for incompati-

ble wastes .......................................... 264.199 264.199Assessment of existing tank ..................................... 2264.191

Part 265

Applicability ............................................. 265.190 265.190Assessment and certification ............... 265.191 265.191Response to and disposition of leak-

ing or unfit-for-use tank system . 265.192 265.196Secondary containment ........................ 265.193 265.193General operating requirements .......... 265.194 265.194Waste analysis and trail tests .............. 265.195 265.200Inspections ............................................. 265.196 265.195Closure and post-closure cave ............ 265.197 265.197Special requirements for ignitable or

reactive wastes .................................. 265.198 265.198Special requirements for incompati-

ble wastes ................... 265.199 265.199Design and installation of tank sys-

tems .............................. 3265.192jThe design and installation requirements of proposed

4264.191 have been combined as final §264.192.2 Section 264.191 .Assessment ot Existng Tank System's

Integrity" in the final rule have been added to addressexisting tanks in a manner similar to the existing interimstatus tanks.

3A new §265.192 "Design and installation of tank sys-tems" has been added to address the proper design andInstallation of new and replacement tank systems subject tothe Part 265 standards (e.g.

TABLE 2.-STANDARDS FOR TANK SYSTEMS

Standard Interim status and permitted Accumulation INew and replacement Existing New and replacement Existing

Initial and periodic integrity assessments (§ 264.191, § 265.191) .......................................................... NA x NADesign and installation standards, including need for external corrosion protection (§ 264.192, x NA x NA

§ 165.192).1

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TABLE 2.-STANDARDS FOR TANK SYSTEMS-Continued

Interim status and permitted Accumulation 2Standard New and replacement r Existing New and replacement Existing

Secondary containment with leak detection (§ 264.193, § 265.193) ................................................ x x 44 x x &4

(when installed) (when tank system (when installed) (when tank systemreaches 15 years reaches 15 yearsof age, unless of age. unlessleaking) leaking)

General operating requirements (@ 264.194, § 265.194) ................................ x x x xInspections (§ 264.195. § 265.195) ............................................................................................................ x x x xResponses to releases (§ 264.196, § 265.196) ..................................................................................... x x x xClosure and Post-closure care (§ 264.197, § 265.197) .......................................................................... x x x x 5Special requirements for ignitable and reactive wastes (@ 264.198, § 265.198) ............................... x x x xSpecial requirements for incompatible wastes (§ 264.199, § 265.199) ............................................... x x x xW aste analysis and trial tests (§ 265.200) ................................................................................................. x x a NA NA

I A generator who generates greater than 100 kg but less than 1,000 kg of hazardous waste in a calendar month and who accumulates hazardous waste in quantities exceeding 6,000 kgor accumulates hazardous waste for more than 180 days (or for more than 270 days if he must transport his waste, or offer his waste for transportation, over a distance of 200 miles or more)is subject to the interim status and pernlitting requirements.

Except as provided in 1, generators of 100 to 1,000 kg of hazardous waste in a calendar month are not covered by the interim status and permitting requirements of this rutemaking.Rather, these generators will need to continue to comply with the requirements as promulgated on 51 FR 10174-10178 on March 24, 1986. These requirements appear in § 265.201 of today srulemaking.

Tank systems used to store or treat EPA Hazardous Waste Nos. F020, F021, P022, F023, F026, F027 must provide secondary containment within two years of the date of promulgation.4 For those existing tank systems for which the age cannot be determined and documented, secondary containment must be provided within eight years of date of promulgation unless the

facility age is known to be greater than 7 years, in which case, secondary containment must be provided by the time the facility reaches fifteen years of age or within two years of the date ofpromulgation, whichever comes later.

s Existing accumulation tank systems are not subject to the § 265.197(c), (d). (e)-requirements for preparation of closure, post-closure, and contingency plans for such or financialresponsibility for complying with such plans.6 The § 265.200 standards are applicable to interim hazardous waste tank systems. Permitted tank systems must comply with the General Waste Analysis requirements in § 264.13.

III. Overall Strategy for Regulation ofHazardous Waste Storage andTreatment Tank Systems

This portion of the preamble firstreviews the significant conclusions uponwhich the proposed regulation wasbased. Then it explains how commentsand further analysis by the Agencyperformed in response to commentshave led to changes in the regulation. Inbrief, the Agency has confirmed that asubstantial number of hazardous wastetank systems are likely to-be leakingand may lead to substantial risks tohuman health and the environment. TheAgency has confirmed its earlierconclusion that the best regulatorystrategy for hazardous waste tanksystems is one that focuses on soundprimary containment and effective andrapid detection and response to leaksfrom the primary containment structure.The best means of ensuring theseobjectives for most tank systems issecondary containment with interstitialmonitoring.

A. Proposed Hazardous Waste TankSystem Regulations

1. Problems Associated With TankSystems

In the June 26, 1985, hazardous wastetank system proposal, the Agencyexplained that many hazardous wastestorage and treatment tank systemswere continuing to release hazardouswastes to the environment through suchfactors as tank system failure andoperator error and that these releasescould present significant risks to humanhealth and the environment.

The preamble to the June 26,1985,proposed rule referenced three sourcesof information as the basis for the

determination that many hazardouswaste tank systems were releasing theircontents to the environment and thatthese releases presented significantrisks:

e Several EPA-sponsored studiescompleted in 1984;

* Information from the public,industry, and State and localgovernments, including survey resultsand studies: and

* Internal Agency informationpertaining to damages, or threats ofdamage, caused by releases ofhazardous wastes from tank systems.

These studies also allowed theAgency to identify what appeared to bethe major causes of tank systemreleases. These were external corrosion,tank structural failure, piping andancillary equipment failures, impropertank system installation, and operatorerrors.

EPA's 1980 and 1981 hazardous wastetank regulations did not address manyof these problems. While externalcorrosion is a major cause of failure inunderground storage tanks, corrosionwas not adequately addressed in thepre-existing standards. Other significantdeficiencies in the 1980/1981 rules werecited in the preamble to the proposedrule. Among other things, there were nopermitting standards for undergroundhazardous waste storage and treatmenttanks that cannot be entered forinspection. For a complete discussion ofthe limitations of the 1980/1981 RCRAtank standards, see the preamble to theproposed revised tank systemregulations (50 FR 26447, June 26, 1985).

2. General Approach

The June 26, 1985, proposed regulationaddressed hazardous waste tank

systems (i.e., tanks and ancillaryequipment) in contrast to the 1980/1981regulations that simply addressedhazardous waste tanks. The proposedrules were based on the premise that theproper management of hazardous wastestorage or treatment tank systemsshould rest on a combination of propertank system design, secondarycontainment or an equivalentmechanism, and operational practices.A variety of technical approaches wereexamined and evaluated for their abilityto prevent releases from entering theenvironment. Design and operatingmeasures such as design andinstallation standards, leak detection,certification requirements, and the useof corrosion protection wereincorporated into the proposedregulatory strategy to ensure thecontinued integrity of the primary tanksystem during its useful life.

The major components of theproposed regulations are summarizedbelow:

a. Existing Hazardous Waste TankSystems. Existing tank systems wereidentified as tank systems already inoperation or for which installationcommenced prior to the effective date ofthis final rule. Retrofit of existing tanksystems with secondary containmentwas a key element of EPA's proposedstrategy. Full secondary containmentwould have been required within oneyear after the effective date of this finalrule. This requirement would apply to alltank types including aboveground,inground, and underground tanks.

An alternative to secondarycontainment was also proposed forinterim status and permitted tanksystems. In the case of aboveground and

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inground tank systems, this alternativewould require secondary containmentfor the aboveground portions of the tanksystem provided that a ground-watermonitoring program was implemented.In the case of underground tanksystems, other than those storing ortreating dioxin-containing wastes (listedHazardous Waste Nos. F020, F021, F022,F023, F026, and F027), owner/operatorscould substitute a ground-watermonitoring program combined with leaktesting every six months in lieu of fullsecondary containment. The proposedregulation would have allowed interimstatus and permitted tanks to obtainwaivers from the requirement to providesecondary containment or its equivalentif the owner/operator could demonstratethat no hazardous waste or hazardouswaste constituents would migrate toground water or surface water "at anyfuture time."

The proposal also required that thestructural integrity of existing interimstatus and permitted tank systems beassessed and certified by a qualifiedand registered professional engineer.The assessment would consider thepotential for corrosion of undergroundmetal tank systems and would require aleak test for underground tanks or aninternal inspection for above oringround tanks. The integrityassessment would also considerwhether the design was adequate tohandle vehicular traffic, floods, andseismic phenomena.

Under the proposed regulations, anexisting tank system found to be unfit-for-use or leaking would have to betaken out of service and closed,repaired, or replaced. A replaced tanksystem would have to be equipped withsecondary containment before beingbrought into service. These requirementswere applicable to interim status,permitted, and 90-day accumulationtank systems.

b. New Hazardous Waste TankSystems. The proposed regulation wouldhave required that all new permitted,interim status, and 90-day accumulationtank systems of any type (e.g.,aboveground, inground, or underground)be equipped with secondarycontainment. New tank systemrequirements would have beenapplicable to all hazardous waste tanksystems that were newly installed (e.g.,new tank systems and tank systems thathad been used previously).

The proposed standards for new tanksystems generally incorporated thesame design, installation, operation, andresponse requirements for leaks orreleases as proposed for existing tanksystems. Since a new installationinvolves installing a total tank system

(primary tank and secondarycontainment) rather than just thesecondary containment system, EPAproposed additional design andinstallation standards for new tanksystems. These include structuralintegrity design standards for theprimary tank vessel and installationstandards and certification for both theprimary and secondary containmentsystems.

c. Hazardous Waste AccumulationTank Systems. The Agency proposedthat 90-day accumulation tank systemsbe subject to many of the samestandards as other new and existingtank systems. One major exception wasthat the ground-water monitoringalternative would not be allowed forowners and operators of 90-dayaccumulation tank systems that werenot permitted. Other Part 265 standardswere not proposed for accumulationtank systems, including: (a) anassessment and certification of tanksystem integrity, (b) provision forcorrosion protection, (c) allowance of arequest for a variance from thesecondary containment requirements,and (d) preparation of closure plans,contingent closure, and post-closureplans, and financial responsibility. Thebasis for not proposing these standardswas the lack of a mechanism, such as apermit, to act as a framework for theinteraction between the owner/operatorand EPA that the Agency believedwould be needed to establish andimplement the ground-water monitoringand other requirements.

d. Small Quantity Generators. TheJune 26, 1985, proposed hazardous wastetank system rules didnot address theextent to which the new Subpart Jstandards should apply to smallquantity generators (SQGs). A majorelement that was unresolved at proposalwas the application of a secondarycontainment requirement for tanksystems owned or operated by smallquantity generators. In the proposed ruleto establish a hazardous wastemanagement system for generators of100 to 1,000 kg of hazardous waste permonth, EPA proposed that thosegenerators who store wastes in tanks forgreater than 180 days (270 days if theaccumulated waste is shipped over 200miles), or who store over 6,000 kg, wouldbe subject to Parts 264 and 265, as wellas the requirement to obtain a RCRApermit (see 50 FR 31287; August 1, 1985).In the preamble to the August 1985proposed rule, EPA explained that itsaw no basis for distinguishing betweenfacilities owned or operated by thesegenerators from other hazardous wastefacilities and that the proposedsecondary containment requirements for

tank systems, if finalized, would applyto such facilities.

Neither the June 1985 proposedhazardous waste tank systemregulations nor the August 1985 SQGregulation proposed a specific set ofrevised hazardous waste tank systemstandards applicable to generators of100 to 1,000 kg of hazardous waste permonth who store up to 6,000 kg ofwastes in tank systems for less than 180(or 270) days. For this reason, finalstandards for these tank systems are notincluded in this final rule. However,EPA will propose in the near future, in aseparate notice, revised hazardouswaste tank system standards applicableto these small quantity generators.

3. Development of Regulatory Approachat Proposal

Central to the June 1985 proposedrevised hazardous waste tank systemstandards was the requirement thatthese tank systems be provided withsecondary containment or its equivalent.Under the proposal, owners or operatorsof existing interim status or permittedtank systems would be required to equipthose tank systems with completesecondary containment or specificcombinations of partial secondarycontainment, tank system integritytesting or semi-annual leak testing, andground-water monitoring. The purposeof these requirements was to protectagainst human health andenvironmental damage that would occurif the tank systems developed leaksbecause of corrosion or othercircumstances.

The principal basis for therequirement of secondary containmentor its equivalent was the conclusion,drawn from several sources, that manytank systems have leaked and thatothers were likely to leak in the future.The preamble to the proposed regulationcited EPA studies, information fromother governmental sources, andmaterials in the rulemaking docket tosupport the conclusion that the otherrequirements of the proposed standards(such as proper design, installation, andoperating practices) would not besufficient to protect human health andthe environment from the effects ofhazardous waste that would leak fromtank systems (50 FR 26448; June 26,1985).

The preamble to the proposedregulation explained that protection ofhuman health and the environment'may not require the containment of allreleases by means of an impervioussecondary containment structure...An approach may be to rely upon earlyrelease detection systems and a rapid

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response program. .." Id. Thepreamble discussed, and solicitedcomment upon, two method of detectingreleases-inventory monitoring andtank testing. The preamble explainedthat both of these methods of releasedetection appeared to haveshortcomings. Inventory monitoringappeared unlikely to detect smallerleaks, and tank testing, which wasdeveloped for underground gasolinestorage tanks, was not clearly reliable indetecting leaks of 0.05 gallons per hour.The uncertainties associated withrelease detection methods led theAgency to believe that an alternative tofull secondary containment could not bebased solely on release detection; itwould have to combine periodic releasedetection methods with ground-watermonitoring.

The regulatory strategy for theproposed regulations was an outgrowth,in part, of the philosophy expressed inthe preamble to the January 12, 1981,interim final regulations for hazardouswaste tanks. That preamble explainedthat requirements for storage facilities,as distinguished from disposal facilities,should have as their goal thecontainment of materials during thestorage period. See 46 FR 2807; January12, 1981.

The preamble to the June 1985proposed regulation solicited commentson other regulatory strategies; theAgency said that it would reconsiderthese strategies before promulgatingrevised hazardous waste tank 'systemstandards. The alternative regulatorystrategies discussed in the preamble tothe proposed regulation were: (1) thecombination of secondary containmentand ground-water monitoring; (2)national risk-based standards; (3)minimum national standards with avariance from the containmentrequirement based upon risk; (4)minimum performance standards; (5)forced retirement of underground tanks;and (6) a ban on underground tanks.(See 50 FR 26451-26453; June 26, 1985.)

B. Development of Regulatory Strategyand Requirements for the FinalRegulation

The Agency received numerouscomments on the proposed regulation. Inaddition, the Agency's Office of SolidWaste and Emergency Response andOffice of Toxic Substances havegenerated additional data and technicalinformation that relate to the regulationof hazardous waste tank systems. Sincethe June 1985 proposal, the Agency hasre-examined the need for regulations,the strategy underlying the proposedregulations, and the technical optionsavailable to address the problems

associated with hazardous waste tanksystems. In the discussion that follows,the Agency explains these issues andthe policy and technical conclusionsupon which these final regulations arebased.1. Problems Associated With HazardousWaste Tank Systems

The studies that the Agency reliedupon at proposal and additional studiesconducted subsequent to proposaldemonstrate that there is a significantproblem that these regulations willaddress. At this time, it is not possible toquantify the extent of the problem.These studies show, however, that asignificant number of existing tanksystems are likely to be leaking, now orin the future. Leaks are likely tocontaminate ground water and posehuman health risks. Approximately16,000 existing hazardous waste tanksystems are subject to the requirementsof these regulations. Uncontrolledreleases from these tank systems couldpose substantial human health risks.

At proposal, the Agency concludedthat a substantial number of tanksystems were likely to be leaking. Thisconclusion was based principally oninformation derived from several studieswhich showed that a substantial numberof tank systems were leaking or werelikely to leak and that releases weresuspected of impacting or threatening toimpact community ground-water wellsystems and/or surface waters (50 FR26448, 26459, and 26460; June 26, 1985).However, because of limitations in thetype of information collected in studiesof tank systems, it was impossible toestimate the actual number of leakinghazardous waste tank systems or toestimate the extent of the problem withany precision.

Some commenters questioned theconclusion that releases from hazardouswaste tank systems pose serious healthand environmental problems. However,no commenters submitted any data toassist the Agency in estimating howmany hazardous waste tank systemsmay be leaking, and no systematicstudies of hazardous waste tanksystems have been performed. Thus, it isstill not possible to quantify the numberof leaking hazardous waste tanksystems. The studies the Agency hasconducted since proposal, however,have demonstrated that the number maybe substantial. The Agency's Office ofSolid Waste and Emergency Response(OSWER) performed a nationwide studyof over 12,000 reports of releases fromunderground tank systems storingpetroleum and chemical products. TheAgency's Office of Toxic Substancestested over 400 motor fuel storage tank

systems. The OSWER study shows thata substantial number of undergroundtank systems may be leaking. The OTSstudy appears to confirm thatconclusion, in that: approximately 35percent of the tank systems tested didnot pass a tank system tightness test.These studies support the conclusionthat a substantial number of hazardouswaste tanks also may be leaking.

A number of commenters assertedthat petroleum and gasoline tank systemdata could not be used to indicatepotential problems with respect toreleases from hazardous waste tanksystems. They presented no data,however, to substantiate their claimsthat hazardous waste tank systemswould leak at a different rate thanproduct storage tank systems. As isexplained below, the major causes ofreleases from tank systems areunrelated to the characteristics of thematerial stored in the tanks, assumingthat the stored material is compatiblewith the material of construction of thetank system. The principal causes ofreported tank failures are externalcorrosion, installation problems,structural failure, spills, and overfillsdue to operator errors, and ancillaryequipment failure. There are no datafrom which to conclude, or reason tobelieve, that these problems would notoccur in hazardous waste tank systemswith approximately the same frequencyas for the petroleum or chemical storagetank systems.

The OSWER study conducted sinceproposal included chemical andpetroleum storage tank systems.Significantly, the results were similar forthese two types of tank systems,confirming that the propensity for tanksystems to leak does not varysignificantly with the characteristics ofthe material stored.

2. Causes of Releases From TankSystems

a. Corrosion. At proposal, the Agencyidentified external corrosion as a majorcause of underground tank systemfailure. The basis for this conclusionwas a study conducted by the AmericanPetroleum Institute (API), whichanalyzed nearly 2,000 leaks fromunderground gasoline storage tanksystems. The API study concluded thatexternal corrosion of underground tanksystems was the predominant cause oftank and piping failure; 75 to 80 percentof the tank and/or piping failuresreported resulted from subsurfacecorrosion of steel tanks and/or piping.

Commenters criticized the use of thisstudy, asserting that differences in thechemical and physical properties

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between petroleum products andhazardous wastes made the studyinapplicable. As is noted above, thesecriticisms contradict the results of theAPI study itself, since 75 to 80 percent ofthe tank system failures were reportedto be caused by corrosion due to contactwith soils, not the material in the tank.

The majority of tank systems in theAPI survey were of bare steelconstruction and had no corrosionprotection. On the basis of the availabledata, EPA has concluded that this is alsothe case for hazardous waste storageand treatment tank systems. In 1982-1983, the Agency sponsored a nationalsurvey of hazardous waste facilities. Areport prepared for EPA, "NationalSurvey of Hazardous Waste Generatorsand Treatment, Storage, and DisposalFacilities Regulated Under RCRA in1981," presents the survey'smethodology and conclusions. EPAfound that steel is the most commonmaterial of construction for underground(73 percent) and aboveground (84percent) hazardous waste tank systems.Overall, about 75 percent of allhazardous waste tank systems areconstructed of carbon steel. Few ofthese tank systems are believed to havecorrosion protection.

Other studies the Agency relied uponat proposal showed that externalcorrosion is one of the principal causesof underground tank system failure. Forexample, a study of 800 undergroundtanks in Ohio conducted by a companyspecializing in cathodic protectionindicated that at least one undergroundmetal tank failure can be expected in 55percent of the gasoline stations over a 15year period and that failures can beexpected at 70 percent of the stationsover a period of 20 years.

The OSWER study conducted afterproposal of the hazardous waste tanksystem regulation has confirmed thatexternal corrosion is a principal cause ofunderground tank failure. It shows that,excluding those releases for which acause was not specified and thosereleases caused by operator errors,about 22 percent of the reported releaseincidences were due to some type ofcorrosion (28 percent for undergroundchemical tanks and 21 percent forunderground petroleum tanks). Inadditin, it is likely that many of thenonspecific causes reported, such as ageand holes, were also due to corrosion.Of the corrosion incidences, only about5 percent were attributed to internalcorrosion (10 percent for undergroundchemical tanks and 5 percent forunderground petroleum tanks).

The Spill Prevention Control andCountermeasure (SPCC) database andthe Pollution Incident Reporting System

(PIRS) database provided valuableinformation on the causes of failure andreleases from aboveground storagetanks. Since aboveground tanks are notin contact with corrosion-inducing soils,external corrosion was not a majorfailure mode for these tanks. It doescause failure in aboveground tanks,however. Exclusive of failures causedby operator error and naturalphenomena, failure by all forms ofcorrosion was 2.2 percent in the PIRSdatabase and 6.2 percent in the SPCCdatabase. Based on a review ofavailable data on underground andaboveground tank systems, EPA expectsthat the aboveground portions ofonground and inground tanks wouldexperience external corrosion failuressimilar to that of aboveground tanks. Onthe other hand, the bottoms of ongroundtanks and below ground portions ofinground tanks constructed of steel andother metals would likely have externalcorrosion failure rates similar tounderground tanks.

b. Structural Failure. At proposal, theAgency identified structural failure asone of the causes of underground tanksystem failure. For example, the APIstudy discussed above indicated that theprimary cause of fiberglass tank failureswas breakage or physical separation ofthe tank wall. The OSWER studyconfirms this conclusion, although,based on the study results, it is notpossible to identify the specific causesof structural failure. Qualitatively,failures were reported as fabricationdefects, design defects, mechanicalfailures, or structural failures. The studyshows that, excluding those releases forwhich a cause was not specified andthose releases caused by operatorerrors, structural failure accounted forabout 45 percent of the release incidentsreported (38 percent for undergroundchemical tanks and 45 percent forunderground petroleum tanks). As istrue of external corrosion, there is noreason to believe that structural failurewould not also be a significant problemwith hazardous waste underground tanksystems. Because of the similarities infabrication, handling, and installationbetween hazardous waste tank systemsand petroleum and chemical storagetank systems, the Agency believes thatstructural failure is likely to occurregardless of whether hazardous waste,petroleum products, or chemicals arestored.

Based on the SPCC and PIRSdatabases, in the case of abovegroundtanks, structural failure accounted forbetween 6 and 7 percent of the reportedfailures.

c. Ancillary Equipment Failure. Atproposal, EPA identified failures of

ancillary equipment, including pipingsystems, as a significant cause ofreleases from above ground tanksystems, citing the analysis of over 2,000incidents of spills of oil or hazardoussubstances'reported under EPA's SpillPrevention Countermeasu'res (SPCC)plans and the Coast Guard's PollutionIncident Reporting System (PIRS). Thisanalysis showed that, if failures due tooperator error and natural phenomenaare excluded, between 85 and 90 percentof these release incidences resulted fromfailures of piping systems (includingfailures of pumps, flanges, couplings,interconnecting hoses, and valves). EPAalso cited studies on the occurrence ofleaks in underground piping due tocorrosion. One study showed that theaccumulated number of leaks inunderground piping increasesexponentially with time, starting atabout 5 years from the date ofinstallation and increases by a factor of10 every 6 years. The API surveydiscussed previously also indicates thatcorrosion of underground piping andancillary equipment is a major cause ofreleases from underground tanksystems.

The OSWER study confirms theconclusion that failures of ancillaryequipment are major causes of releasesfrom tank systems. The study showsthat, excluding those releases for whicha cause was not specified and thosereleases caused by operator errors,ancillary equipment failures accountedin 38 percent of the reported releaseincidents (35 percent for undergroundchemical tank systems and 38 percentfor underground petroleum storage).

Several commenters expressed theopinion that data derived frompetroleum storage tanks should not beused to predict the failure rates forpiping and other ancillary equipment inhazardous waste tank systems becausethey believed that petroleum tanksystems are more often pressurized thanhazardous waste tanks (presumably apressurized pipe, pump, valve, etc.would be more likely to leak than a non-pressurized component). They alsoasserted that there were differences inthe length of piping. No data wereprovided to substantiate their claims,however.

There is no basis for concluding thathazardous waste tank systems are lesslikely to have pressurized piping orother ancillary equipment, especially inthe underground situation where pumpsmust usually be used to remove fluidsfrom the tank. In addition, the Agency isunaware of any information showingthat piping length is substantiallydifferent for hazardous waste versus

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petroleum tank systems. Somecommenters asserted that piping lengthsof about 200 feet are typical of gasolineservice station tank systems comparedto the 50 feet of piping assumed by EPAfor a typical hazardous waste tanksystem. Other commenters stated thatpiping lengths for many hazardouswaste tank systems are often greaterthan 50 feet, with one commenter citinga piping length of 8,000 feet. While EPAdoes not consider the latter figure to betypical of many hazardous waste tanksystems, it is likely that piping systemsused at gasoline service stations arewell within the range of piping lengthscharacteristic of hazardous waste tanksystems.

The corrosive properties and presenceof suspended solids in many hazardouswastes might actually cause higherfailure rates of valve stem seals, shaftseals in pumps, flanged and threadedconnections, and other tank seals inhazardous waste tank systems than inpetroleum storage tank systems.Suspended solids, sludges, and debrisare found in many hazardous wastes,and their presence in hazardous wastetank systems might cause clogging andblockages, which can cause pressurebuildup in pumps and pressurizedsegments of the piping system. Thehigher pressure combined with theabrasive properties of some hazardouswastes might lead to accelerated wearon rotating shaft and valve stem seals.

EPA concludes that the externalcorrosion rate and the incidence ofleakage from piping and ancillaryequipment for underground hazardouswaste tank systems are likely to be atleast as great as those of petroleumstorage tank systems. Thus, re-examination of the potential forancillary equipment to cause tanksystem failure confirms that theregulation of hazardous waste tanksystems must include ancillaryequipment.

d. Operator Errors. At proposal, EPAidentified overfills, overflows, and otheroperational errors as a significant causeof releases of hazardous waste to theenvironment. For example, in the SPCCand PIRS data bases, operator error andoverfills/overflows accounted for 32 and47 percent of the release incidentsreported. Recent studies confirm thisconclusion. The OSWER studyidentified this as the leading cause ofreleases for both petroleum andchemical storage tank systems. Typicaloperator errors were: (1) overfill oftanks; (2) incomplete closure of valves;(3) opening of wrong valves; (4) impropermating of hose connections; (5) improperrepair or maintenance; and (6) accidents

(e.g., forklift damage to a tank orbreaking of a valve stem through the useof a wrench to open a stubborn valve).There is no reason to believe thatoperators of hazardous waste tanksystems will commit fewer errors thanoperators of other tank systems.

Aside from the immediate threat ofmigration to ground and surface waters,overfills can contribute to acceleratedcorrosion failure in underground,inground, and onground tank systemsstoring hazardous wastes. Many of thehazardous wastes contain acids, bases,and salts which if spilled into the soilsurrounding the tank system can causethe soil to become corrosion-inducing.Also, microbial action on organics,halogenated organics, and sulfur-containing hazardous wastes that haveleaked into the soil adjacent to theexterior tank wall can producebiodegradation products that are highlycorrosive (i.e., organic acids, HCI, andsulfuric acid).

3. Risks Posed by Releases FromHazardous Waste Tank Systems

The report, "The National Survey ofHazardous Waste Generators andTreatment, Storage, and DisposalFacilities Regulated Under RCRA in1981," indicates that about 16,000hazardous waste storage and treatmenttanks were used at about 3,800 facilities(exclusive of small quantity generators)in the United States in 1981. As isexplained above, many of these tanksystems probably are leaking or can beexpected to leak in the future. Leaks ofhazardous waste can be expected topose a significant risk to human healthand the environment in part becauseleaked materials may contaminateground water and cause individuals tobe exposed to the hazardousconstituents in the wastes. In addition,risks to human health and theenvironment may be introduced byexposure to contaminated surface waterand air.

The recent OSWER survey ofdocumented release incidents fromunderground storage tank systemsshowed that over 75 percent of theincidents resulted in contamination ofthe soil and that the ground water wascontaminated in more than 50 percent ofthese incidents. In addition, the samesurvey showed that, of the undergroundchemical release incidents, 74 percentresulted in contamination of the groundwater. Leaks from hazardous waste tanksystems may also cause ground watercontamination.

Other available data confirm thatleaking tanks present serious threatsbecause they allow hazardouschemicals to contaminate soils and

ground water. In a study entitled"Assessment of the Technical,Environmental and Safety Aspects ofStorage of Hazardous Waste inUnderground Tanks," dated February1984, the Agency compiled studiesconducted by the American PetroleumInstitute and by .various State andmunicipal agencies. The studiesanalyzed leaks from petroleum productand other tank systems. One of thestudies was conducted by the CaliforniaWater Quality Board-San FranciscoBay Region.

In 1982, the Regional Board initiated asurvey of 1,950 facilities. Of the facilitiessurveyed, 480 reported current or prioruse of underground tanks or sumps. Ofthese, the Board selected 87 judged ashaving a high potential for leakinghazardous substances. These tanksystems were non-vaulted, solventwaste tanks and sumps, withoutcorrosion protection, and at least sevenyears of age. These high priorityfacilities were required to conduct acontamination assessment. Of the first80 facilities reporting, 64 had subsurfacecontamination although at least 5 ofthese were from sources other than thetank system. At many of these facilities,highly toxic materials, such as benzeneand other solvents, contaminated soilsand/or ground water. At 10 facilities,soil contamination levels exceeded 1,000ppb for at least one chemical; 11facilities reported ground waterconcentrations of over 1,000 ppb.

This study also included casehistories of two facilities with leakproblems reported prior to the initiationof the larger study of 1,950 facilities.These case studies of release incidentsat these additional facilities reported thefollowing: In one case, a solvent storagetank leaked for one and one-half yearsbefore it was detected, This leakresulted in the contamination of threeaquifers with a cleanup cost of over $12million. In the second case, two publicand several private water supply wellswere contaminated and cleanup costsby the end of the first year had reachedapproximately $10 million.

The conclusion that leaks from tanksystems may present substantial risks issupported by EPA's "Hazardous WasteTank Risk Analysis." This analysismodeled what EPA believes are currenthazardous waste tank systemmanagement practices. The results ofthis analysis indicate that currentpractices lead to a substantialprobability of release to theenvironment from tank failures due tocorrosion, rupture, improper installation,gasket failures, and operator errors.

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Federal Register / Vol. 51, No. ,134 / Monday, July 14, 1986 /,Rules and Regulations 25431

Current practices tend to allowreleases to continue undetected until therelease becomes obvious. In manycases, undetected releases can beexpected to contaminate valuableresources and threaten human healthand the environment.

The estimated release volumes varydepending upon the type of tank systemand the quantity of waste handled.Underground and large volume tanksystems tended to have the highestestimated releases. However, all tanksystems, including aboveground andsmall volume tank systems, wereassociated with significant releasevolumes and, therefore, risk to human'health and the environment. In general,all tank systems modeled under currentmanagement practices were associatedwith release volumes that wereapproximately 10 percent or less of thetank system throughput over the 20 yeartime horizon. Although small volumetank systems were estimated to haverelatively small release volumes, evensuch small release -volumes may pose asignificant risk to human health and theenvironment as a result of the toxiceffects associated with hazardous wasteconstituents. Chronic exposure tohazardous waste cbnstituents may leadto such adverse health effects as canceror damage to various organ systems(e.g., kidneys, liver, and reproductivesystems).

The Hazardous and Solid WasteAmendments of 1984 placed additionalbans and limitations on disposing ofhazardous waste in landfills. EPA mustmake ban determinations on all RCRAwaste by November 1990. The first suchdetermination, regarding solvents anddioxins, was made in a proposed ruledated January 14, 1986. Others arecurrently under development and stillothers will follow at regular intervals.When effective, these regulations maysubstantially increase the amount ofwastes in storage and treatment tanksystems, thus increasing the aggregaterisks posed by these systems if they arenot managed properly.

4. Technical Options for AddressingProblems Associated With LeakingTanks

The incidence of releases resultingfrom the major causes discussed in thepreceding section tends to vary slightlyfrom study to study depending on theparticular population surveyed. In allcases, however, high among the mostfrequent causes are:

" Corrosion;" Structural failure;*. Piping and ancillary equipment

failure; and

e Operator error leading to spills oroverfills.

Before determining how best toaddress the problems associated withleaking tank systems, the Agencyevaluated the technical optionsavailable for addressing the principalcauses of releases. As is explainedimmediately below, there weresignificant drawbacks to reliance upon-any method other than secondarycontainment with interstitial monitoringfor the effective identification of andresponse to releases from hazardouswaste tank systems to the environment.

a. Corrosion. Corrosion of tanksystems is usually caused by improperselection of construction materials and/or inadequate protection againstexternal corrosion. The Agencyexplored the possibility of addressingthis problem by ensuring that the designof the tank system was appropriate (i.e.,that the materials of construction werecompatible with the waste being stored)to prevent internal corrosion fromoccurring and, that effective corrosionprotection be applied to steel tanksystems and metal components of non-steel systems to address externalcorrosion problems. Corrosionprotection might consist ofspecifications of corrosion-resistantcoatings or liners, or cathodic protectionsystems.

The corrosion process is very complexand is influenced by factors such as:oxidizing agents, electrolytic activity,acidity, moisture levels, soil resistivity,temperature, bacterial action, and otherfactors. Corrosion protectionapproaches include cathodic protection;-paints, coatings, and linings; solublecorrosion inhibitors; electrical isolation;and the use of corrosion resistantmaterials.

EPA was concerned whether mostowner/operators have the knowledgeand technical specialization to evaluateand select the most appropriatecorrosion protection measure. In orderto assure the application of a properlevel of expertise in this phase of wastemanagement, EPA evaluated thebenefits of requiring owner/operators toobtain certification of proper corrosiondevice selection and system design byqualified corrosion experts.Independent, qualified corrosion experts

- would be required. As a minimum, theywould need to specify the appropriatedesign and installation requirements. Inthe case of a field-fabricated corrosionprotection system, a corrosion expertwould supervise the installation of thesystem.

Even if owner/operators had thenecessary expertise or obtained theservices of qualified experts, corrosion

problems would remain. The Agency isaware of no data establishing thecomplete effectiveness of corrosionprotection measures applied to single-walled steel tanks. The reliability ofmany protection methods depends uponeffective maintenance and inspectionpractices which are subject to humanerror or negligence. Corrosion protectionmeasures, such as cathodic protectionsystems, coatings, and moisture barriers,may be effective in significantlyreducing rates of corrosion, but they donot necessarily stop corrosioncompletely Therefore, corrosionprotection measures will reduce, but noteliminate, failures resulting fromcorrosion. In addition, corrosionprotection does not address causes ofreleases other than corrosion. Thus, inaddition to corrosion protection, someform of release detection is required toenable an appropriate response in theevent of a release from a tank systemprotected against corrosion.

b. Structural Failure. Structural failureproblems can be attributed to a largedegree to improper design anainstallation. However, inadequatequality assurance and quality controlduring the manufacture of tank systemswould also be a major concern. Thesolution, again, would involve applyingproper levels of expertise at the designand installation stages and adequatequality assurance during manufacture.Certification by a qualified professionalengineer that the design and installationis in accordance with sound engineeringpractices and applicable standards canbe of considerable benefit. The majorlimitations of design and installationstandards is that once a tank system isdesigned, built, and installed,improvements in the standards or evenerrors in applying the standards cannotbe retrofitted in most instances. Forexample, it is usually impossible toretrofit existing tank systems with bettermaterials of construction or with thickerwalls.

In addition, improved tank designstandards cannot assure the properinstallation and maintenance of thetanks. That a substantial number ofreleases from tank systems haveresulted from structural failuredemonstrates that improved designstandards have not obviated the needfor regulations ensuring that tanksystems are installed and operatedappropriately. In addition, some form ofrelease detection is required to enablean appropriate response in the event ofa release from even a well-designed andinstalled tank system.

c. Ancillary Equipment Failure. Datacited in the preamble to the proposed



Federal Register / Vol. 51, No. 134 / Monday, July 14, 1986 / Rules and Regulhtions

regulation and the recent OSWERsurvey attributed a significant number ofleaks to ancillary equipment failure.Most of these releases appear to haveresulted from mechanical and thermalstresses common to daily operation.These stresses, however, are mostevident on the components of thesystems that are most susceptible towear, such as pipes with flanges or.threaded connections, valves, andpumps. Pumps and valves, for example,are designed with moving parts andseals that periodically deteriorate withuse. In addition to these stress-inducedfactors, underground piping issusceptible to the same corrosioninfluences discussed previously fortanks.

The principal leak prevention measuresuggested for ancillary equipment is itsproper design and installation. Thedesign should match its intendedfunction taking into consideration firstthe proper material of construction. Thematerial of choice must be compatiblewith the array of substances that willpass through it. Specifically, the materialof construction must match the thermalcoefficients of expansion and corrosiveproperties of the substances transportedthrough it. A quality audit of tanksystem installation, especially toprevent loose fittings, poor welding, andmalaligned gaskets, will prevent manyleaks.

The difficulties of addressing theproblems of structural failure andcorrosion of ancillary equipment aresimilar to those of the tanks themselves.Thus, in addition to proper design andinstallation of ancillary equipment,some form of release detection isrequired to enable an appropriateresponse in the event of a release fromeven a well-designed and installedpiping system.

A basic type of construction thathelps prevent releases is piping withwelded connections. Devices are alsoavailable that enclose specificcomponents of the ancillary equipmentsystem such as jacketed (double-walled)'piping and sealless (canned) pumps.These devices-forms of secondarycontainment-are capable of containinga release in the event of a failure of theprimary containment system.

d. Operator Errors. Operator errorsare among the most prevalent causes oftank system leaks and releases. Propertraining and the establishment ofstandard operating procedures andsafety practices can reduce theoccurrence of human errors. Spill controland contingency plans, training plans,and operating procedures are importantand are required to obtain permits for

tank systems and other treatment,storage, and disposal facilities (TSDFs).

Some operator errors can be avertedby installing engineered safeguards.Overflow protection devices can beinstalled on tank systems to providewarning to the operator and/or toshutdown transfer pumps when the tankreaches full capacity. Protective guardscan be installed to prevent vehicular orforklift damage to tanks. Proper taggingor labeling of valves and piping can helpalleviate human error in operatingvalves. Tank design standards, such asspecification of a minimum freeboardrequirement and a minimum volumerequirement for secondary containment,can also help to reduce theconsequences of human error. However,even the best training programs andoperations practices will not completelyeliminate human error.

e. Multiple Causes of Releases. In -addition to the direct methods describedabove for controlling or reducing thelikelihood of releases from tank systems,there are a number of monitoringmethods and backup devices that arecapable of addressing, to varyingdegrees, the problems associated withreleases due to corrosion, poor design,fabrication, and/or installation, pipingand other ancillary squipment, andoperator error. These include tanksystem inspection, leak detection, andsecondary containment.

i. Inspections. Physical inspectionscan be conducted in order to detectexisting leaks and/or to identifyproblem areas that cazi lead to releasesif not repaired. If the release is detectedearly and response measures are taken,inspections can reduce risks to humanhealth and the environment. Inspectionscan commence at the time a tank systemis installed and can be conducted on aperiodic basis thereafter TestBconducted at the time the tank system isinstalled include various non-destructive methods such as tanktightness tests, soap tests, ultrasonictests, spark tests, acoustic emissionstests and radiography tests

Periodic inspections can includevisual inspections of tanks (foundations,connections, coatings, and tank walls),internal inspections for enterable tanks(roof, structural members, shell, andbottom), and visual inspection of pipesand ancillary equipment. Inspectionequipment includes penetrant dyes,vacuum boxes (for seam testing),ultrasonic instruments, and radiographicequipment.

While regular visual inspections canreduce risks, they cannot be relied uponcompletely. There are many problemsthat visual inspections would not reveal

(e.g., loose fittings, external corrosion ifonly the inside of the vessel can-beinspected) and, because visualinspection is an episodic rather than acontinuous process, detection ofreleases may occur after significantquantities of waste have migrated to theenvironment. This problem can bealleviated if a mechanism is available tocontain the release until the release isdiscovered.

ii. Leak Detection, If a leak is detectedearly and response measures are taken,this approach can reduce risks to humanhealth and the environment. Theconcept of early detection andsubsequent corrective action as anappropriate method of addressing therisks presented by releases fromhazardous waste tank systems was thebasis for the ground-water monitoringalternative for existing tanks that was amajor component of the proposedregulation. For underground tanksystems, this alternative consisted of-se-ni-annual tank tightness testingcombined with ground-watermonitoring. The Agency received manycomments on this approach; most ofthem identified asserted problems andadvantages that commenters believedwere associated with various methodsof leak detection. In response to thesecomments, the Agency has re-examinedeach of these methods and hasconcluded that they are not reliableenough to provide long-term control ofleaks from hazardous waste tanksystems.

There are a number of leak detectionmethods that can be applied to tanksystems. There are various methods oftank testing, including pneumatic, valvemanometer, liquid level bubble,fabricated float, laser beam, overfill/standpipe, buoyancy sensor, andcapacitance probe tests. Other methodsof leak detection are inventorymonitoring, unsaturated zonemonitoring, and ground-watermonitoring.

(a) Ground-water monitoring: Anumber of commenters identifiedproblems with ground-water monitoring.Commenters pointed out that ground-water monitoring alone only detects aleak after the hazardous waste hasreached the ground water and that theleak would potentially be undetecteduntil long after the leak occurred. Othergeneral problems cited by commentersincluded issues of accuracy, especiallyfor certain materials, hydrogeologicsettings, and background contamination.

Commenters pointed out severalproblems with ground-water monitoringas it might be applied specifically totank systems. They noted that the

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design of the ground-water monitoringsystem could be complicated if there aremany tanks located in close proximity toone another. The proper location, depth,and number of wells required were allmentioned as items of concern if thesystem was to be effective. In facilitieswhere pipes are interconnected betweenmultiple tanks, commenters stated thatit is often impossible to pinpoint thesource of ground-water contamination(e.g., determine which tank is leaking).Some commenters stated thatmonitoring wells could provide apathway for hazardous waste to migrateand contaminate ground water.Commenters also stated that soilcharacteristics and the presence ofinstalled foundations and undergroundpiping or equipment in the vicinity of thetank can sometimes lead to channelingof underground contamination,effectively bypassing the ground-watermonitoring points, making it improbablethat meaningful ground-watermonitoring can be implemented forhazardous waste tank systems with asingle sampling point. They stated thatmultiple sample wells, properly placed,are required to detect contaminationeffectively. They also stated that thedetermination of the direction of flow inground-water aquifers is difficult andmakes the placement of sampling wellseven more difficult.

The Agency agrees with somecommenters that ground-watermonitoring, while it can be useful forother types of treatment, storage, anddisposal facilities, will not by itselfallow detection and identification of thereleases from hazardous waste tanksystems within a timeframe that willpermit rapid responses to the releases.Ground-water monitoring is not aseffective as secondary containment withinterstitial monitoring in protectinghuman health and environment fromleaking hazardous waste tank systemsbecause it detects leaks substantiallylater than monitoring the interstitialvolume between the tank and thesecondary containment system.Reducing the length of time required todetect a release is important in reducingrisks of environmental damage. TheAgency is also concerned that ground-water monitoring might have reducedeffectiveness in detecting releases fromlong lengths of piping or individualtanks when multiple tanks are in closeproximity to each other.

EPA, however, does not agree withthe commenters who claimed thatground-water monitoring systems areunreliable in detecting leaks orinherently dangerous as conduits ofcontamination. While the design of an

effective ground-water monitoringsystem requires careful consideration offacility structure and site hydrogeology.EPA believes that the design of a systemwhich will reliably detect leaks is quitefeasible. EPA agrees with thecommenters who stated that multiplewells may be required to detectcontamination effectively and that careshould be taken to ensure that thedirection of ground-water flow isproperly determined. Also, whileimproperly-installed or improperly-maintained wells may provide apathway for contamination, suchimproper installation or maintenance isnot an appropriate reason to rejectground-water monitoring.

(b) Tank testinq: Tank testing, or tanktightness testing, can be useful indetecting many leaks from tanks orancillary equipment. It, too, however, isnot sufficiently reliable to serve as along-term method of controlling leaksfrom hazardous waste tank systems.

Many commenters addressed tanktesting with various points of view.Some claimed that the method wasunreliable; others claimed that leaks of0.05 gallons per hour could reliably bedetected-especially in smaller tanks.The Agency commenced its own studyof leak testing, but the results of thatstudy were not available for this rule.

The recent OTS survey of motor fuelstorage tank systems concluded thatcommercial tank testing methods werenot reliably detecting releases in therange of 0.05 gallons per hour. In manycases, fairly substantial leaks remainedundetected. OTS concluded thatcommercial methods and fieldprocedures could be modified toimprove their reliability, however. OTSanalysts adapted a commercial methodto correct deficiencies in the methodsand generated a tank testingmethodology that they determined candetect releases under testing conditionsof 0.1 gallons per hour with 95 percentconfidence. OTS also concluded that itis imperative that information be madeavailable on both the accuracy andprecision of tank testing methodologies.

The Agency concludes that tanktightness testing can play a role inregulating hazardous waste tanksystems. Properly performed tanksystem tightness tests appear to be ableto detect leaks of approximately 0.1gallons per hour. During the phase-inperiod, these tests may be used toconduct assessments of tank systemintegrity. This will enable theidentification of most leaking tanksystems. However, undetected leaks ofbelow 0.1 gallons per hour could still beconsiderable over the period of a year.

The Agency has concluded thatpermitting hazardous waste leaks of thatsize to be undetected and, therefore,uncorrected. would be unacceptableover the long term.

The re-examination of ground-watermonitoring and leak testing led theAgency to reject the ground-watermonitoring alternative contained in theproposed rule. Because both ground-water monitoring and hazardous wastetank system integrity assessments,including tank system tightness tests,are not completely reliable in detectingreleases so that response actions can betaken before the releases reach groundwater or surface water, EPA found thatthis alternative does not provide equalprotection to human health and theenvironment as secondary containmentwith interstitial monitoring. Thisconclusion is further supported by theresults of the Agency's risk analysisconducted as a part of this rulemaking.

(c) Inventory monitoring: In thepreamble to the proposed regulation, theAgency expressed serious doubts aboutinventory monitoring as a method ofdetecting leaks from hazardous wastetanks. Re-examination of the issues hasconfirmed that the regulation should notrely on this method. Among other things,the OTS survey of underground motorfuel storage tank systems found thatowner/operators were not able toperform inventory monitoringeffectively. Only 41 percent of theattempted cases resulted in thedevelopment of usable data. TheAgency believes that the use ofinventory monitoring may be even moredifficult and problematic for owners andoperators of hazardous waste tanksystems.

(d) Unsaturated zone monitoring:Unsaturated zone monitoring is atechnique for monitoring conditions inthe zone of aeration lying between theearth's surface and the water table. Thisis a zone where vapors can migraterelatively easily. A number of devicescan be used to monitor conditions in thiszone. They rely on the principles ofthermal conductivity, electricalresistivity, solubility, and vaporpressure. Soil-gas detectors are a widelyused form of vadose or unsaturated zonemonitoring. They function best inpourous soils where vapors can migrateeasily to a sensing device. Thesedetectors are most effective whenmonitoring highly volatile gases inrelatively dry soil.

Some commenters stated thatunsaturated or vadose zone monitoringshould be considered as a replacementfor ground-water monitoring, because itwould be capable of detecting leaks

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prior to the release of hazardousconstituents to ground water. EPAagrees that releases from hazardouswaste tank systems should be detectedbefore they reach ground water.However, in analyzing these commentsand other available information on thecapability and reliability of unsaturatedzone monitoring, EPA has concludedthat unsaturated zone monitoring is anunproven technology for reliablydetecting releases from hazardous wastetank systems at this time.

EPA evaluated the use of unsaturatedzone monitoring as a possible substitutefor ground-water monitoring. TheAgency used mathematical models tosimulate the effectiveness of soil-gasmonitoring in analyzing these commentsand other available information on thecapabilities and reliability ofunsaturated zone monitoring using thebest available information on thetransportation of vapors through soil. Inevaluating the reliability of unsaturatedzone monitoring, EPA assumed that (1)monitoring would occur in theexcavation zone; (2) the systemmonitored is a carbon steel undergroundtank containing the highly volatile wastedichloromethane; (3) the tank is locatedin a homogeneous backfill of knownpermeability; (4) the ground-water tableis deep enough to allow detection of theleak prior to ground-watercontamination; (5) the composition ofthe waste stored in the tank does notvary over the time that excavation zonemonitoring is used; (6) the monitoringwell is located two feet from the tank;and (7) the tank owner/operator canafford and would perform periodiccleanup and repair or replacement of thetank. Overall, these assumptions resultin an evaluation of excavation zonemonitoring under ideal installation andoperating conditions.

The results of the simulation (see"Hazardous Waste Tanks RiskAnalysis," June 1986) show that forvolatile hazardous waste, vapormonitoring in a sand-backfilledexcavation zone under ideal conditionsand combined with immediate responseaction, might reduce the volume ofreleases to the environment nearly aswell as secondary containment: vapormonitoring in the excavation zone,combined with immediate responseaction, reduced baseline releases by 96percent, while secondary containmentreduced them by 98 percent. Thesesimulated results have not beenvalidated with field studies, however,even under the ideal conditionsdescribed above.

EPA agrees that there are argumentsthat can be made regarding the

theoretical superiority of unsaturatedzone monitoring when compared toground-water monitoring or other leakdetection methods for identifyingreleases of volatile materials fromhazardous waste tank systems. TheAgency does not agree, however, that itscurrent state of development is adequatefor full reliance in lieu of secondarycontainment. Rather, EPA believes thatunsaturated zone monitoring is anemerging technology with considerablepromise. Once it has been sufficientlydeveloped and its reliability isunderstood, it could provide a means ofassuring that leaked wastes can beconfined to an area in which remedialaction is practical.

EPA has a number of specificreservations about adopting thisapproach for use as the principalregulatory strategy. Because unsaturatedzone monitoring procedures, includingsoil-gas monitoring, are still relativelynew, there has been little fieldvalidation of their effectiveness,especially for the wide range ofhazardous wastes that will be coveredby this rule. Many wastes are notvolatile, and soil-gas monitoring in theunsaturated zone would not detect theirrelease. In addition, samplerepresentativeness, quality control, theeffect of sampling methods on detectionlimits, and other issues must beresolved. The Agency recognizes thatthere is a special need to focus on theseissues from the standpoint of the uniquecharacteristics of hazardous wastestorage in tank systems. The approachneeds verification over the expectedrange of waste types, hydrogeologicsettings, and waste mobility andpersistence levels. Methods must bedeveloped to distinguish tank systemfailure from background contaminationfrom previous overfills, spills, and/orreleases. Also, in the cases whererelatively lower concentrations ofconstituents are present in hazardouswastes when compared to the levelscharacteristic of stored products or rawmaterials, leaks might lead tocontaminant levels that are below thedetection limits of current unsaturatedzone monitoring techniques.

EPA's Office of Research andDevelopment will be committingsignificant resources over the next 18months in an effort to investigate systemreliability, investigate the propergeometry for placing monitoring devicesaround tank systems, and to identifyacceptable unsaturated zone monitoringsystems. EPA will continue to evaluateunsaturated zone monitoring for itsapplicability in detecting hazardouswaste releases. Although the techniques

are not specifically included in this rule,they could potentially, withimprovement, be employed on a case-by-case basis as part of a technology-based variance application presented tothe Regional Administrator whenseeking an exemption to the secondarycontainment regulations contained inthis rule.

iii. Secondary Containment withInterstitial Monitoring. Secondarycontainment is a method of containingreleases to enable detection ofhazardous wastes leaking fromhazardous waste tank systems.Secondary containment technologiesinclude liners, vaults, and double-walledtanks. When combined with interstitialmonitoring, the overwhelmingadvantage of secondary containment isthat it allows for the detection ofreleases from the primary containmentvessel while providing a secondarybarrier that contains the releasedmaterial before it escapes into theenvironment. The space between theprimary and secondary vessels is easilyand reliably monitored.

There are other benefits to secondarycontainment. Secondary containmentcan isolate the primary tank from highground water and saturated soils,thereby protecting the tank frompotential corrosion by the combinationof water and corrosion-inducing soils. Insome cases, the materials ofconstruction offering the best corrosionprotection against external and internalcorrosion may not be one and the sameor the choice of material for corrosionprotection may not have adequatestructural strength. In these cases, thesecondary containment system and thetank system can be constructed ofmaterials that provide the desiredcombination of properties (e.g., steel orfiberglass tanks in concrete vaults.

Another important benefit is that thesecondary containment system can alsobe designed to provide for containmentand detection of accidental spills andoverfills. For example, in secondarycontainment system designsincorporating vaults and berms, spillsand overfills can be easily detected byvisual examination and alsodecontaminated readily. Thiscompensates for human errors andreduces the reliance upon flawlessoperator performance. Secondarycontainment prevents spills and overfillswhose volume does not exceed thecapacity of the secondary containmentsystem from being released to theenvironment.

Additionally, in the event that a tanksystem is used to store or treat ahazardous waste which was not

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considered at the time the system wasdesigned, secondary containment canprovide protection against designdeficiencies that might otherwise resultin releases of hazardous wasteconstituents.

Secondary containment can affordsecurity for other causes of tank failure.As a secondary barrier, it can eliminatereleases to the environment caused bypoint anode corrosion (e.g., caused by apiece of cinder contacting the tanksurface), collect leakage from loosefittings and worn seals on valves andpumps, and prevent releases due tostructural failure of the tank system.

Table 3 summarizes the Agency'sevaluation of the technical options nowavailable for addressing releases fromhazardous waste tank systems.

5. Regulatory Approacha. Summary of Approach Taken in

Final Rule. As explained previously, theAgency's overall strategy foraccomplishing the statutory goal ofprotecting human health and theenvironment from the risks posed byhazardous waste storage and treatmentfacilities is to prevent the migration ofhazardous waste constituents to groundand surface waters where such releasesmay present a risk to human health orthe environment. A key element of theoverall strategy is the need to detectreleases in a timely manner so that anappropriate response can be made.

The Agency's overall riskmanagement strategy has evolved fromthe following considerations. First, as isexplained in this preamble, there is aneed to address further regulation of

hazardous waste tank systems becausethe current situation most likelypresents significant risks. A number ofstudies have shown that tank systemsare likely to be. leaking or are likely toleak in the future. Releases from tanksystems are likely to contaminateground water and surface water, posingrisks to human health and theenvironment.

Second, based on EPA's review of thetechnical options, as well as therationale expressed in the preamble tothe 1981 hazardous waste tank systemregulations, the Agency has concludedthat a regulatory approach thatemphasizes secondary containment withinterstitial monitoring both satisfies thestatutory objective and is consistentwith the function of tank systems asstorage, rather than disposal units.

TABLE 3.-EVALUATION OF VARIOUS CONTROL TECHNOLOGIES

Ability tocontainrelease to

Problem Technology Function ground and

surfacewaters

External corrosion ....................................... Cathodic protection .................................................................................... Slow corrosion rate .................................................................................... No.Coatings ....................................................................................................... Slow corrosion rate .................................................................................... No.Secondary containm ent ............................................................................. Barrier against waste and corrosive soils .................................... ... Yes.

Internal co rrosion ........................................ M aterials stand ards ................................................................................... Slow corrosion ........................................................................................... No.Coatings ....................................................................................................... Slow corrosion ............................................................................................ No.Liners ............................................................................................................ Protective barrier ......................................................................................... Maybe.

Leaks (Tanks and ancillary equipm ent). Leak detection ........................................................................................... Early warning .............................................................................................. No.Visual inspection ........................................................................................ Early warning .............................................................................................. No.Ground-water m onitoring ........................................................................... Early warning ............................................................................................. No.Vadose zone mon itoring ........................................................................... Early warning ........................................................................................... No.Secondary containm ent ............................................................................ Early warning and containment ............................................................... Yes.

Loss of structural integrity ........................ Design standards ....................................................................................... Proper design ............................................................................................. No.Q uality audit ................................................................................................ Elim inate flaws ........................................................................................... No.Installation standards ................................................................................ Proper installation ...................................................................................... No.Secondary containment ............................................................................ Early warning and containment ............................................................... Yes.

Overfill ......................................................... Protective con trols ................................................................................. Prevent overfill ........................................................................................... No.Secondary containm ent ............................................................................ Early warning and containm ent .............................................................. Yes.

Operator error ............................................ Operator procedures and training .......................................................... Reduce errors . . ................................................................................... No.Secondary containm ent ............................................................................ Early warning and containm ent ................................................................ Yes.

'Promising, emerging technology that may resuh in detection prior to release to ground waters. Currently the subject of intensive EPA research to define the capabilities of existing state-of-the art technology. Research is focusing primarily on volatile materials.

Secondary containment is notexpected to impose economic burdensas explained later in this preamble insection VII. When the potential costs ofcorrective action are considered,secondary containment may result insubstantial savings over the long term.For example, the annualized presentvalue cost of replacing a 4,000 gallonunderground steel tank system with anew tank system with full secondarycontainment and interstitial monitoringwould be about $3,900. On the otherhand, the typical annualized presentvalue corrective action costs associatedwith cleanup of a release from a leaking4,000 gallon single-walled tank systemwould range from about $2,500 (removaland replacement of tank, removal ofcontaminated soil, no ground-watercontamination) to $6,300 (removal andreplacement of tank, removal of

contaminated soil, two years of ground-water treatment correcting one year ofplume growth) or up to $68,000 (removaland replacement of tank, removal ofcontaminated soil, 33 years of ground-water treatment correcting 20 years ofplume growth).

While the focus of today's regulationis on secondary containment, theAgency recognizes that secondarycontainment is not always necessary toachieve the statutory objectives. Froman overall risk management perspective,secondary containment with interstitialmonitoring was selected as a generalrule, subject to the availability ofvariances. This selection was madebecause of the probability of risk inmost cases and the uncertaintiesassociated with leak detection and othertechnologies. While there are some tanksystems that may not require secondary

containment, the Agency has beenunable to identify generically whichtank systems fit into this category.Accordingly, the Agency has included inthe regulations the opportunity forowner/operators to obtain variancesfrom the secondary containmentrequirements of today's regulation.

As is explained further below, theprincipal reliance on secondarycontainment does not mean that allexisting tank systems must be equippedwith secondary containmentimmediately. The regulations provide foran orderly'phase-in of secondarycontainment for existing tank systems,beginning with tank systems believed topose the greatest risk (i.e., leaking tanksystems).

The major features of the Agency'srisk management strategy for new andexisting permitted, interim status, and

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90-day accumulation hazardous wastetank systems, as expressed in today'srule, are summarized below. For thepurpose of today's regulation, the term"new tank system" means not onlynewly-manufactured tank systems thatwill be put into service for the first timebut also those other tank systems thateven if in existence and in use prior tothe promulgation date of today'sregulations are then reinstalled and usedas replacement tank systems for existinghazardous waste tank systems.Likewise, an existing tank system that isnot being used for the storage ortreatment of hazardous waste, but isthen put into service or converted to useas a hazardous waste storage ortreatment tank system subsequent to thepromulgation date of today's regulationis considered to be a new tank system.

The first feature of the regulationconsists of requirements intended tomaintain the integrity of the primarycontainment structure. For both new andexisting tank systems, the final rulerequires that the primary tank system bedesigned properly and that it becompatible with the wastes that arestored or treated. For existing tanksystems not fitted with a secondarycontainment system, a tank integrityassessment (e.g., internal inspection,visual inspection, tank system tightnesstesting) must be conducted by theowner/operator within 18 months of thepromulgation date (12 months of theeffective date) of today's rule to identifyleaks from the primary tank system.Where tank system tightness testing isused, the tests must be able to accountfor temperature fluctuations, tank enddeflection vapor pockets, and effects ofhigh water table. These factors werecommonly cited by commenters to be ofgreatest concern in attaining testingaccuracy and precision and werelikewise found in the OTS survey to becrucial in order to conduct a tanktightness test reliably.

To ensure the integrity of metal tanksystems, all new metal tank systems inwhich all or part of the system is or willbe in contact with the soil or with waterare required to be evaluated forcorrosion potential by a corrosionexpert. The Agency's review ofavailable data indicates that externalcorrosion of metal tank systems is amajor cause of tank failure and releaseto the environment. External corrosionprotection can substantially reduce, butnot eliminate, the potential for releasesfrom metal tank systems. Theassessment of the corrosion potential oflocal conditions by a corrosion expertwill provide an evaluation of the degreeof corrosion protection required in each

situation. As a protective measure forcathodic corrosion protection devices,the rule requires regular inspection/testing of sacrificial anode potential andimpressed current sources. Existing tanksystems need not be retrofitted withcorrosion protection because this wouldbe redundant: the basis of the phase-inof secondary containment accounted forthe fact that most hazardous waste tanksystems currently in use do not havecorrosion protection.

The second feature of the Agency'soverall regulatory approach is properinstallation of the tank systems. Today'srule requires an independent, qualifiedinstallation inspector or professionalengineer to certify that the tank systemis structurally sound before installationand that proper handling procedures areadhered to during installation. Tanksystems must be tested for tightnessprior to use. Tanks and piping must besupported properly, and corrosionprotection must be installed if needed.The design and installationrequirements are intended to preventtank failure and releases due toimproper design and installationpractices, known to be major causes oftank system failures. Theserequirements can also lead to long-termprevention of releases due to structuralfailure and/or corrosion.

The third feature of the Agency'sregulatory approach is secondarycontainment with interstitial monitoringto detect leaks from the primarycontainment vessel. Despite theprovisions requiring proper design,installation, and operation of theprimary containment system, availabledata show that leaks are still likely tooccur. The function of the secondarycontainment and leak detection systemis to ensure that leaks are detectedbefore they migrate beyond the zone ofengineering control (i.e., an area underthe control of the owner/operator that,upon detection of a hazardous wasterelease, can be readily cleaned up priorto the release of hazardous constituentsto ground water or surface waters). Thesecondary containment system collectsand contains releases from the primarycontainment vessel so that releases canbe detected before they migrate into theenvironment. The leak detection systemallows prompt detection of any releasefrom the primary system to thesecondary containment system. The ruleprovides design standards for vaults,exterior liners, and double-walled tanksecondary containment systems. TheAgency's implementation of thesecondary containment requirementsare discussed in further detail later inthis section.

The fourth feature of EPA's approachincorporates provisions for adequateresponses to releases of hazardouswastes. This rule requires that allreleases to the environment be reportedto the Regional Administrator. Oneexception is if a reportable quantity of ahazardous waste constituent is released;in this case, the owner/operator mustreport the release to the NationalResponse Center under CERCLAregulations (in which case, the RegionalAdministrator is informed of the release.If appropriate, the EPA RegionalAdministrator will issue an order orpermit condition requiring correctiveaction. In addition, immediate actionmust be taken to identify and stop therelease, including, if necessary,emptying that part of the tank systemfound to be leaking until the leak hasbeen stopped. The final rule requiresthat a qualified, registered professionalengineer certify that major repairs havebeen properly made before a leakingtank is returned to service. Today's rulealso requires that secondarycontainment with leak detection beprovided for replacement tank systemsand for any component of a repairedtank system that is underground.Additionally if a leak has occurred inany portion of a tank system componentthat is not readily accessible for visualinspection, the entire component, i.e.,either the tank or the entire pipingsystem, must be provided withsecondary containment prior to beingreturned to service.

As the final feature of theseregulations, EPA is requiring owners oroperators of hazardous waste tanksystems to provide adequate closure,and, if necessary, post-closure, care. Allwastes and all contaminatedcomponents, soils, structures, andequipment must be decontaminated orremoved from the site at closure. If allcontaminated compounds, soils,structures, and equipment cannot bedecontaminated or removed at closure,or if the ground water is found to becontaminated, the site must be providedwith post-closure care similar to thatrequired for landfills.

EPA believes that this regulation, byrequiring design and installationstandards for primary containmentstructures, corrosion protection formetal tanks, secondary containment andleak detection, and quick response inthe case of a release from the primarycontainment structure or other spill, andproper closure and post-closure care,will protect tank systems against failureand minimize, by containment anddetection, any releases of hazardouswaste to the environment.

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Federal Register / Vol.. 51, No. 134 / Monday, July 14, 1986 / Rules and Regulations 2

b. Secondary Containment.-i.Secondary Containment Approach. Asexplained previously, EPA hasconcluded that the only demonstratedmethod for ensuring against releases toground water or surface water issecondary containment with interstitialmonitoring. This method greatly reducesthe risks associated with managinghazardous wastes in tank systems (see"Hazardous Waste Tank RiskAnalysis." June 1986).

The Agency considered twosecondary containment options thatwould define the framework of the finalregulation. The first would requireimmediate secondary containment forboth new and existing tank systems.The second would require secondarycontainment within two years for newtank systems, leaking tank systems, andtank systems containing dioxin wastes,but, for other existing tank systems,would require secondary containmenton a mandatory phase-in schedule.

EPA selected the second option as thebasis for the regulation because it willultirfiately lead to the implementation offull secondary containment for all tanksystems, while phasing-in secondarycontainment in a manner that ensuresthat existing tank systems appearing topresent the greatest risks receiveimmediate attention. In addition, it willallow for technological advances in leakdetection or tank system design thatmight increase the opportunity for tanksystems to obtain variances fromsecondary containment or might lead tothe Agency's amending this regulation inthe future. The phase-in scheduleapplies to permitted, interim status, and90-day accumulation tank systems.

The phase-in of secondarycontainment will occur as follows:

(a) Leaking underground components oftank systems (i.e., tank vessel or ancillaryequipment), would require secondarycontainment with leak detection before beingplaced back into service after the leak isdiscovered. Additionally, if a leak isdiscovered in any portion of a tank systemcomponent that is not readily accessible forvisual inspection (e.g., the bottom of aninground tank), the entire component must beprovided with secondary containment withleak detection prior to being returned toservice. These components of tank systemspose the most significant risk to humanhealth and the environment because they arecurrently leaking hazardous wastes to theenvironment and because subsequent leaksmay be imminent and would go undiscovereduntil the next tank integrity assessment wasperformed. If a leak is discovered in a tanksystem component or a portion of a tanksystem component that is readily accessiblefor visual inspection, the component may berepaired and brought'back into servicewithout being provided with secondarycontainment as long as an independent,

qualified registered professionalengineercertifies that the tank system is capable ofhandling hazardous waste without permittingits release into the environment for theprojected useful life of the tank system. Sucha repair is inherently less risky because (a)the system has been certified to be capable ofhandling hazardous waste for its remaininguseful life and (b) the component will beinspected on a daily basis to ensure itsintegrity.

(b) Tank systems storing or treating dioxin-containing wastes (EPA Hazardous WasteNos F020, F021, F022, F023, F026, and F027)that are not shown to be leaking by tankintegrity assessments must be retrofitted withsecondary containment within two years.These wastes are highly potent-andextremely toxic and pose significant risks tohuman health and the environment ifreleased. Additionally, in the event of arelease, cleanup costs can be substantial; forexample, the proposed land disposalrestrictions would require that dioxins incontaminated soils would have to be reducedbelow detection levels prior to land disposal(see 51 FR 1062; January 14, 1986).

(c) The integrity of remaining existing tanksystems must be tested periodically. If a leakis detected through the integrity assessmentor in any other manner, for the reasonsexplained above, the following is required bytoday's regulation. Any component, i.e., tankor ancillary equipment, of a leaking tanksystem that is underground must be provided'with secondary containment with leakdetection before being brought back intoservice. Additionally, if a leak has occurredin any portion of a tank system componentthat is not readily accessible for visual-inspection, the entire component must beprovided with secondary containment withleak detection prior to being returned toservice. In all cases, secondary containmentmust be provided when the tank reaches 15years of age except that, for non-leakingtanks, in no instance is secondarycontainment required sooner than two yearsfrom the date of promulgation of today'sregulation. This schedule provides thataboveground tank systems and componentsof tank systems that are readily accessiblefor visual inspection are given the maximumperiod of time prior to phase-in the secondarycontainment requirements of today's finalregulation.

To ensure that today's regulation is applieduniformly in those situations where anowner/operator.is unable to document theage of his tank system, EPA will assume,based on its study of the age distribution ofhazardous waste tank systems, that the tanksystem is seven years old, the median age ofall hazardous waste tank systems, exceptthaf, if the age of the tank system isunknown, but the facility at which the tanksystem is located is known to be older thanseven years of age, secondary containmentwould be required within two years, or bythe time the facility reaches 15 years of age,whichever comes later.

The Agency considered severalapproaches to phasing-in secondarycontainment for existing tdnk systemsthat do not leak. The studies considering

the incidents of releases from tanksystems and the causes of these releasesdo not identify a single factor thatcorrelates precisely with leaking.Neither the age of the tank system norany other factor allows one to concludethat a particular tank system will leak atany particular time because there are somany variables in the placement of tanksystems, their construction, theirinstallation, and other factors. Assumingthat all other influences were identical,however, there is little doubt that anolder tank system will leak before anewer one. Accordingly, the Agencyselected tank age as the best criterionfor phasing-in secondary containment.

The Agency examined the availabledata to decide what age to select as thebasis for the phase-in. The Agencyselected fifteen years-approximatemedian time to failure for thoseunderground steel tank systems thatwere the subject of studies discusseidpreviously in this preamble.Underground steel tank systems are theonly systems for which reliable data areavailable. Other available information,developed by EPA's Office of ToxicSubstances, suggests that fiberglasstanks may be as susceptible to failure assteel tanks, although the database forfiberglass tanks is not nearly asextensive as for steel tanks.

On the basis that EPA has no data tothe contrary, the phase-in for other tanksystems will be -the same as forunderground steel tanks. The Agencyhas conducted extensive literaturereviews and sought data on failureincidences for various types of tanksystems (e.g., concrete, fiberglass] fromtrade associations and tankmanufacturers and through aninformation request (51 FR 9072, March17, 1986). Unfortunately, no definitivestudies or data have been discovered ormade available to the Agency. EPA willcontinue to seek information on tanksystem failure incidences and, ifappropriate, will consider modifying thebasis of the phase-in in the future.

ii. Variances from SecondaryContainment. Today's rule provides fortwo types of variances: one may beobtained if the owner/operator canshow that alternative design andoperating practices, together withlocation characteristics, will prevent themigration of released materials toground or surface water at least aseffectively as secondary containmentwith interstitial monitoring; the secondmay be obtained if there would be nosubstantial present or potential hazardto human health or the environmentassociated with a release. The variancesare available for permitted, interim

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status, and 90-day accumulation tanksystems, and are explained more fullybelow. Both new and existing tanksystems may qualify for variances.These variances are consistent with theoverall strategy of today's regulation.Secondary containment with interstitialmonitoring is the only generally-reliablemeans to achieve control over releasesbefore they pose risks to human healthand the environment. Secondarycontainment is not necessarily an end initself. If other methods can be shown ona case-by-case basis. to achieve theregulation's goals, there is no reason torequire secondary containment.

The variances included in. today'sregulation differ from the ones in theproposed regulation. Sections 264A193(ijand 265.193(f) in the proposed ruleprovided a variance from all or part ofthe secondary containmentrequirements if the owner or operatorcould demonstrate to the RegionalAdministrator that the location of thetank system and alternative design and.operating practices would preventhazardous waste from reaching groundor surface waters at any future time.Owners and operators storing ortreating dioxin-containing hazardouswastes with EPA codes F020,, F021, F022,F023, FOZ6, and F027 could not obtainthis variance and would he required to-provide full secondary containmentwithin one year of the effective date ofthe final regulation.

Many commenters- to the proposedrule objected to the stringency of thevariance as proposed, especially thelanguage "at any future time." Somecommenters stated that this languageexceeded the requirement of § 3004(a) ofRCRA, to promulgate regulations "asmay be necessary to protect humanhealth ard the environment." Manycommenters suggested the substitutelanguage "during the active life of theunit and post-closure care period," as apossible alternative to "at any futuretime."

Several commenters suggested that arisk-based variance should be allowedand that the protocols for establishingthis variance should be consistent withEPA's ground-water protection strategy.Commenters also suggested otherfactors, that they believed would beimportant when considering the grantingof a risk-based variance. Othersproposed that the. entire regulation beestablished on the basis of risk. Amongthe suggested risk factors were wastetoxicity, site location,, site hydrogeology,soil characteristics, ground-waterquality, climate,, tank size, waste storagetime, and the. migration potential andenvironmental persistence of the waste

evaluated in a manner similar to thatprovided in EPA's proposedimplementation of the land disposalrestrictions (50 FR 23250; May 31, 1985].,

The Agency has attempted to basetoday's regulation on risk to the extentthat it is possible to do so. Accordingly,immediate secondary containment isrequired for leaking components of tanksystems that cannot be visuallyinspected, and tank systems containingdioxin-containing wastes; and oldertank systems that, based on tankintegrity assessments, are considerednon-leaking will be phased-in first. Thelack of substantive data on numbers,sizes, locations of tank systems, thetypes of hazardous wastes stored inindividual tank systems, and site-specific hydrogeologic conditions makeit impossible to go beyond this level ofrisk-based rulemaking at this time.However, the Agency- concludes, as didmany commenters, that a risk-basedvariance from the secondarycontainment requirements, should beavailable to owner/operators to takeinto account site-specific situations.

For this reason, the final rule, unlikethe proposed rule, allows both a risk-based variance from secondarycontainment and a technology-basedvariance. The risk-based variance canbe obtained if the owner/operator,including the owner/operator of a tanksystem managing dioxin-containinglisted hazardous wastes, demonstratesthat there will be no substantial presentor potential hazard to human health orthe environment in the event hazardouswaste is released from the storage ortreatment tank system. This variancedoes not exempt the tank system owneror operator from the requirements of thisregulation other than secondarycontainment. Even where it isdemonstrated that secondarycontainment is not needed, the Agencybelieves that it is important tomaintaingood day-to-day operating practices, asrequired iri today's revised Subpart Jstandards. Relaxation of therequirement for secondary containmentmust not be construed to mean that thefacility is licensed to be a hazardouswaste disposal facility. Adherence togood operating practices will. not posean undue burden on the hazardous "waste tank system owner/operators.

The risk-based variance is notavailable for new underground tanksystems. Section 3004(o)(4) of RCRArequires that new underground tanksystems be provided with leak detectionmethods that detect leaks at the"earliest practicable time." EPA hasconcluded that new underground tanksystems may qualify for the technology-

based variance if they demonstrate thata leak detection method detects leaks tothe environment before they reachground water or surface waters.However, the risk-based variance-through which the tank system wouldnot need to be equipped with leakdetection-would not satisfy therequirements of section 3004(o)(41.

The technology-based variance,similar in nature to the proposedvariance, allows owner/operators asecond variance mechanism if theowner/operator can demonstrate to theRegional Administrator that alternativedesign and operating practices, togetherwith location characteristics willprevent the migration of any hazardouswaste or hazardous waste constituentsinto the ground water or surface waterat least as effectively as secondarycontainment with interstitial monitoring.This variance would be granted if theowner/operator demonstrates, forexample, that a leak detection methodnot believed generally reliable will bereliable for his tank system because ofits characteristics, location, and otherfactors such as the wastes stored ortreated. Reliable detection of leaks orspills would be followed by responseaction.to prevent contamination ofground water or surface water. Someowner/operators may he able todemonstrate that unsaturated zonemonitoring will be effective for theirtank systems. Varfances will not beallowed for tanks for which ground-water monitoring is claimed to beeffective, however. The overall strategyfor regulating hazardous waste tanksystems is based on the prevention ofcontamination of ground water byreleases from tank systems.

There are two changes from proposalwith respect to this variance. Thevariance is now technology-based andrequires that an alternative systemprovide equivalent protection assecondary containment rather than ashowing of no migration of hazardouswaste or hazardous waste constituentsat any future time. As explained above,this change is consistent with theAgency's overall strategy for regulatinghazardous waste tank systems asexpressed in this preamble.

The second change in this varianceallows owners and operators storing ortreating EPA Hazardous Wastes 7020,F021, F022, F023, F026, and F027 to applyfor this technology-based variance. EPAis allowing owner/operators storing ortreating dioxin-containing listed wastesthe opportunity to apply for thetechnology-based variance because it ispossible that such owner/operators maydevelop a technology alternative to

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secondary containment that ,ensuresprotection of human health and theenvironment.

The two variances are available tointerim status and 90-day accumulationtank systems as well as to permittedtank systems. Procedures areestablished in Part 265 of today'sregulation through which owner]operators of interim status and'90-dayaccumulation tank systems may apply "for the variances.

EPA intends to -issue guidance onthese variance provisions prior'to theeffective date ,of'this regulation. EPAwill continue to investigate thecombinations of factors (e.g., wastetypes, hydrogeologies, potential releasevolumes) that may enable -the Agency todescribe generically the situations inwhich tank systems would be eligiblefor variances from the secondarycontainment requirements. To the extentthat the Agency is successful in thiseffort, it will be reflected in'theguidance. Additionally, guidancerelating to the risk-based variance willreflect the concept of differentialprotection based on the use, value, andvulnerability of the ground water asembodied in EPA's Ground WaterProtection Strategy.

iii. Small Quantity Generators. Undertoday's final rule, the Part 264 and 265requirements, including the secondarycontainment requirements,, apply Inthose generators :of'100 to 11000 kg ofhazardous waste per month who aresubject to interim status or permittingrequirements because they store thesewastes on-site for more than 180 (or 270)days or store more than.6,000 kg ofwaste. Under the conditions of long-termstorage or treatment, the -potential forrelease of hazardous waste to theenvironment becomes significant or -thequantity of waste present, over time,becomes significant. The Agency seesno basis for distinguishing thesegenerators from other hazardous wastefacilities. (See .50 FR 31287: August 1,1985.)

6. Regulatory Options Not Selected

The preamble to the proposed ruledescribed several regulatory optionsconsidered by EPA. The Agency choseto propose secondary containment witha ground-water monitoring alternative,but invited comments on six alternateregulatory options:

* Combination of secondarycontainment and ground-watermonitoring;

" National .risk-based 'standards;" Minimum national standards with a

variance from containment requirementsbased on risk;

& Minimum performance standards;

* Ban of underground tanks; -and* Forced retirement of underground

tanks.a. Combination of Secondary

Containment and Ground-WaterMonitoring

This strategy would require bothsecondary containment ,and ;ground-water monitoring for all tank systemsrather than permitting the use of onlyone of these approaches. This approachwould be similar to the approach.required for surface impoundments andlandfills where, under section 3004(a) ofRCRA, ,each new, replacement, orlateralexpansion of existing landfills andsurface impoundments 'is required toinstall two or more liners and a leachatecollection system and a ground-watermonitoring system.

The overwhelming majority ofcommenters on this issue stated thatground-water'monitoring was anunnecessary additional requirement fortank systems equipped with secondarycontainment on the basis that theadditional protection resulting fromground-water monitoring is negligible,particularly when -compared to cost.Some commenters suggested thatperiodic ground-water monitoring beused to confirm the effectiveness ofsecondary containment systems.

Upon analysis of the issue, EPAconcludes that secondly containment,combined with a requirement for aninterstitial leak detection system,obviates 'the need for ground-watermonitoring. An interstitial leak detectionsystem (one located in -the interstitialspace between the primary -tank systemand the secondary containment system)will detect leaks before the wastes arereleased to surface or ground waters,thus fully protecting human health andthe environment. Since this leakdetection method detects releases,before they enter the environment, itsatisfies section 3004-o)4)'s requirementthat new underground tank systems 'beequipped with means for detectingreleases to the environment at theearliest practicable time. 'While section3004(o) of RCRA requires that certainnew land disposal facilities he equippedwith groundwater monitoring as well asdouble liners, the :statute doesnotimpose similar requirments for newunderground tanks. Because interstitialmonitoring in tanks with secondarycontainment is extremely reliable, theAgency is not imposing additionalground-water monitoring requirementsas a matter of policy.

b. National Risk-based Standards. Analternative to generally-applicabledesign and operating standards is theconcept of risk-based standards. Risk-based standards would vary based on

the degree of risk:presented by acombination of factors, such as sitelocation, typeof hazardous wastemanaged, proximity io ground water,and proximity to populated areas.Hypothetically, fsnb factors could bearrayed in the form of a matrix, withdifferent levels'of -control prescribedaccording to the relative Aisk posed by aparticular combination Df factors.

Most commenters were in 'favorofsome type of iisk-hased:standard,although .no ,wokable msggestions -onhow to.implement national Tisk-basedstandards were included in thecomments. The Agency has analyzedpossible risk-hased approaches forstorage and treatment tank systems,accumulation lank systems, and smallquantity generator tank systems. Ahazardous waste tank failure model toexamine risks associated with certainwastes, -in a variety of settings, wasdeveloped. The estimated releasevolumes from specific Lelease -eventswere used to estimate human healthrisks through the use of a transport andexposure model.

The Agency 'concluded that nationalrisk-based standards cannot bedeveloped at this time because ofinsufficient information regarding: .(1}Waste stream constitnentconcentrations; (2),hydrogeological datafor the hazardous waste 'tankpopulation; (3) distannes betweendrinking water wells and hazardouswaste tank systems, and ) populationsrelying on drinking water wells. In theabsence of such information, the Agencyhas decided that a 6isk-based variancewould be more appropriate thannational risk-based standards.

As explained previously ,today'sregulation does, however. take broadconcepts of riak into 'consideration to theextent possible with existing data. Thephase-in'of secondary containment forexisting hazardous waste tank systemsrequires that tank systems generallylikely ,to pose the greatest risks (leakingtanks and tank3 containing dioxinwastes) be provided with secondarycontainment before ,oth-r tank systems.

c. Minimum National Standards witha Variance From ContainmentRequirements Based on Risk. As analternative to risk-based standards, theproposed regulation requested commenton the concept of risk-based variancesto minimum national standards.Numerous comments were submittedthat encouraged the Agency to adoptthis strategy. One commenter didexpress reservations about thecost andtime that would be necessary 'to performthe demonstration.

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In today's final rule, EPA hasprovided two separate mechanisms forobtaining a variance from secondarycontainment requirements. Thesemechanisms are discussed in sectionIII.B.5.b.ii of this preamble.

EPA acknowledges that the cost ofmaking thb demonstration of nosubstantial present or potential hazardto human health and the environmentwill, in many cases, exceed the cost ofproviding secondary containment.However, the Agency believes it isappropriate to allow a variance forthose facilities that can make thenecessary demonstration, and for whomthe cost of demonstration would not beexcessive.

d. Minimum Performance Standards.Under this approach, EPA wouldestablish minimum Federal performancestandards for hazardous waste tanksystems. The example used at proposalwas-"all new tank systems must belocated, designed, operated, maintained,and closed in a manner that will assureprotection of human health and theenvironment." Under this option, stateswould have the option of expanding onthe Federal performance standards byissuing more specific standards. Instates choosing not to elaborate on theFederal performance standards, owner/operators of hazardous waste tanksystems would have the responsibilityof demonstrating that their tank systemsdo not endanger human health and theenvironment. This would require a case-by-case assessment 6f the protectivemeasures needed to achieve theperformance standard.

In the worst case situation that statesdid not expand upon the minimumperformance standards, individual riskassessments would have to beperformed for every tank system used tostore or treat hazardous waste. Thiswould be incredibly resource intensivefor owner/operators because of theprobable need to gather additionalinformation on local hydrogeologies,distances to drinking water wells; andpopulations relying on these wells. Itwould also require considerable stateand Agency resources to review andanalyze the information developed bythe owner/operators to show that theirsystems would be protective. The threecommenters who supported thisapproach did not offer a means ofovercoming the resource implications ofthis alternative approach. For the abovereasons, the Agency has rejected broadperformance standards as the basis fortoday's final rule. Today's rule does, ofcourse, develop minimum standards thatmust be applied. States may impose

more rigorous standards if they chooseto.I e. Ban of Underground Tanks. In thepreamble of the proposed rule, EPAdiscussed the banning of hazardouswaste from underground tanks as yetanother alternative regulatory strategy.This option had previously been raisedfor public comment in the preamble tothe January 12, 1981, permittingstandards and was opposed by mostcommenters at that time.

Numerous comments were againreceived. Nearly all of the commentersstated that a ban of underground tanksystems that stored or treatedhazardous waste was not necessary,because proper management of suchtank systems can prevent releases fromimpacting the environment, Onecommenter suggested, however, thathazardous waste be banned fromunderground storage unless no othermeans of aboveground storage werefeasible.

EPA believes that, withimplementation of the regulatoryapproach being promulgated today, theuse of hazardous waste underground.storage tank systems will not endangerhuman health or the environment. TheAgency is also aware that National FireCodes and space limitations frequentlygive tank system owner/operators noalternative to underground storage. Allunderground tank systems that do notqualify for a variance will, over time, beequipped with secondary containmentwith interstitial monitoring. This willensure that leaks are discovered prior totheir release to ground water or surfacewaters, thus protecting human healthand the environment.

f Forced Retirement of UndergroundTank Systems. In the preamble to theJune 26, 1985, proposal, EPA alsodiscussed the regulatory option of forcedretirement of tank systems. i e.,mandating replacement of tank systemsupon reaching a predetermined age..

Numerous comments were submittedthat stated that forced retirement is nota fair and reliable means of regulatingunderground tank systems. However,one commenter advocated a forcedretirement of underground tank systemsat the time the system reaches the agepreviously determined as being the endof the useful life of the system.

Today's final regulation mandatesthat secondary containment withinterstitial monitoring be phased-in sothat all existing hazardous waste tanksystems would be provided withsecondary containment by the time theyreach 15 years of age, including thosesystems that do not appear to beleaking. This approach could be

considered equivalent to the forcedretirement of tank systems.

As explained previously in thispreamble, EPA has determined thatsecondary containment with interstitialmonitoring is the only reliable means ofconsistently detecting releases fromhazardous waste tank systems. TheAgency has selected a phase-inprocedure that will ultimately lead tothe implementation of full secondarycontainment with interstitial monitoringfor all tank systems, while phasing-insecondary containment in a manner thatensures that existing tank systemsappearing to present the greatest riskswill receive immediate attention. EPArejected basing the phase-in solely onthe results of tank integrity assessmentsbecause the Agency is concerned thatthe reliahility of such assessments issuch that relatively small releases arelikely to go undetected. Thus, in thisfinal rule, EPA has selected an overallregulatory approach that could beconstrued as forced retirement in someinstances.

IV. Changes to Final Rule From Proposal

A. Additions

Additions to the rule since proposalthat were not discussed previously inthis preamble are: (a)'new definitions(onground tank systems and sumps); (b)exemption of closed-loop recycling tanksystems; and (c) a clarification of thedefinition of ancillary equipment.

1. Definitions

a. Onground Tank System. Today'sfinal rule adds to part 260 the definitionof an onground tank. An "ongroundtank" is a device that meets thedefinition of "tank" in § 260.10 and issituated in such a way that the bottomof the tank is on the same level as theadjacent surface. In the proposedregulation, this type of tank wasconsidered an aboveground tank. Thisnew definition is added to clarify therevised requirements in § 264.196 and§ 265.196, which now make clear that ifa leak occurs on the bottom of anonground tank, secondary containmentmust be provided for the entire tankprior to the tanks being returned toservice.

b. Sumps. A tank is defined in 40 CFR260.10 as a stationary device, designedto contain an accumulation of hazardouswaste which is constructed primarily ofnon-earthen materials (e.g., wood,concrete, steel, plastic) which provide,structural support. If a sump meets thisdefinition of a tank and if it is used tomanage hazardous waste, it would havebeen subject to all of the hazardous

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waste tank system standards proposedon June 26, 1985.

Two commenters urged EPA todistinguish between a tank and a sump.One commenter explained that sumpsare generally made of reinforcedconcrete, open on top, and used tocontain liquids for very short periods oftime. Also, the commenter pointed outthat liquids enter a tank throughattached piping, while liquids oftenenter a sump by flowing directly acrossa floor draining into the sump. Similarly,the second commenter described sumpsas typically composed of impermeablematerial, possessing little or no attachedpiping, and presenting little hazard ofrelease of hazardous waste into theenvironment. Because of these perceiveddifferences, one commenter suggestedthat sumps should not be subject to thehazardous waste tank requirements. Theother, while recognizing that sumps"may also represent a potential sourceof contamination," stated his belief thatit was inappropriate to apply all of therequirements for tanks to sumps. A thirdcommenter was concerned that thebroad definition of a tank would resultin process drains being defined ashazardous waste tanks.

Sumps meeting the definition of tankthat manage hazardous wastes arecovered by today's regulation, asexplained below. In response tocomments and to clarify therequirements of today's final regulation,EPA has added a definition of sump intoday's rule. A "sump" is "any pit orreservoir that meets the definition oftank, and those troughs/trenchesconnected to it, that serves to collecthazardous waste for transport tohazardous waste storage, treatment, ordisposal." Sumps can serve a variety ofapplications including collection of rainrunoff from a treatment, storage, anddisposal facility, collection of spills orreleases as part of a secondarycontainment system, and collection ofhazardous waste discharged from amanufacturing process.

In general, EPA believes that sumpsmay present the same potential for leaksand releases as hazardous wastestorage and treatment tanks. Forexample, the San Francisco RegionalWater Quality Board studied thereleases of hazardous wastes intoground water and found leaking sumpsto be a contributing factor along withleaking hazardous waste tanks. Thus,EPA concludes that sumps generallyshould be subject to the same standardsas tanks. However, where a sump is apart of a secondary containment systemused to collect or contain spills andreleases of hazardous wastes, it would

be redundant to require secondarycontainment as the sump is part of asystem that is already serving as asecondary means of containment. Thus,EPA will not require secondarycontainment for sumps that serve aspart of secondary containment systems,but the other standards for hazardouswaste tank systems will apply.

A situation where a sump is used tocollect potential spills or leaks ofhazardous waste from processequipment, e.g., accidental releases froma distillation column, would be asituation where the sump serves as partof a secondary containment system.Therefore, secondary containment forthe sump would not be required.However, it is EPA's intention thathazardous waste tank systems,including sumps used to transporthazardous wastes, are managed in amanner that would ensure protection ofhuman health and the environment.Thus, if a sump is used to collectintentional discharges of hazardouswastes, e.g., the discharge of hazardouswaste from a centrifuge directly on thefloor and into a sump, the sump wouldhave to meet the secondary containmentand other requirements of today'sregulation.

c. Ancillary Equipment. In theproposed rules, EPA defined ancillaryequipment as any device used todistribute, meter, or control the flow ofhazardous waste to or from the storageor treatment tank(s), including but notlimited to such devices as piping,fittings, flanges, valves,. and pumps.Several comments were received thatrequested EPA to clarify to what extent(i.e., how much of) the ancillaryequipment was intended to be coveredby the regulations.

EPA's intention was and still is toinclude all ancillary equipment that isused in the handling of the waste fromits point of generation (i.e., that point atwhich the material is initiallyconsidered to be a hazardous waste) tothe hazardous waste storage/treatmenttank(s) and, if applicable, from thehazardous waste storage/treatmenttank(s) to a point of disposal on-site orto a point of shipment for disposal off-site. It is the Agency's belief that, inmost cases, the point at which thematerial will initially be considered tobe a hazardous waste is the point atwhich the material leaves a processtank or area. Thus, the definition ofancillary equipment has been revised intoday's final regulation to include thisclarification.

2. Exclusion of Closed-Loop RecyclingTank Systems

EPA received a number of commentswhich argued that the Agency hadsubstantially underestimated thenumber of tanks potentially affected bythe proposed rule because it did notconsider tanks that are part of theproduction process and thus integrallytied to reclamation operations. Thecommenters further argued that suchtank systems were not handling solid orhazardous wastes; rather, they wereaccumulating materials to be used in theactual production process. In responseto these comments, EPA published anotice in the Federal Register thatrequested information on the number oftanks potentially affected and commenton the question of when tank systemswould be a part of a closed-loopreclamation process and thus notmanaging solid or hazardous wastes.The notice also outlined the Agency'stentative view of the conditions underwhich a tank system would beconsidered part of a closed-loop system.(See 50 FR 51264; December 16, 1985.)

EPA received approximately 40comments on this notice; virtually all ofthem supported an exclusion along thelines indicated in the notice. Thesecommenters endorsed the Agency'sreasoning, stated that the numbers oftanks potentially involved were quitelarge (in the tens of thousands of tanks),and indicated that a number ofcommenters already were submittingvariance applications for these tankspursuant to 40 CFR 260.31(b). [40 CFR260.31(b) allows any person to petitionthe Agency for a variance fromclassifying as a solid waste thosematerials that are reclaimed and thenreused as feedstocks within the originalprimary production process in which thematerials were generated if thereclamation operation is an essentialpart of the production process.] In a fewcases, variances have already beengranted. Some of these commenters alsourged the Agency to expand the scope ofan exclusion beyond that outlined in theDecember notice to include tanksystems where there is no hardconnection between tanks, where drumsor containers are used instead of tanks,or where reclaimed products are notreturned to the original process thatgenerated them.

A few commenters, however, urgedthe Agency to retain its present rulesand to rely exclusively on the closed-loop variance provision in § 260.31(b) toexclude tank systems involved inclosed-loop reclamation processes. Inthese commenters' opinion, utilizing the

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existing variance is preferable becausethe Agency could evaluate on anindividual basis how safely a facility isstoring secondary materials beforedeciding whether an exclusion iswarranted. A particular concern raisedby these commenters was air emissionsof volatile materials from uncoveredtanks.

EPA has decided to adopt anexclusion substantially along the linesindicated in the notice and has placedthis exclusion in § 261.4 of theregulations. EPA is taking this stepbecause these types of operations arebest viewed as part of the productionprocess, not as a distinct wastemanagement operation. The Agency, inessence, is determining generically thattank systems that meet the requirementsspecified below satisfy the criteriaspecified in § 260.31(b)(1) through (8) forgranting a closed-loop variance. Ascommenters stressed, these types ofclosed-loop tank systems are veryprevalent in a wide variety of industries(see § 260.31(b)(2)), for example,chemical manufacturing,pharmaceutical, dry cleaning.Commenters indicated that the totalnumber of tanks that would be affectedare in the tens of thousands. Substantialvolumes of secondary material areinvolved (estimated in the billions ofpounds annually), and significanteconomic savings are associated withthe reclamation activity (§ 260.31(b)(1)).Several commenters also indicated thattheir production processes would not beeconomically viable without therecovery step and subsequent reuse ofthe recovered product.

The activities discussed here likewisesatisfy the remaining variance factors.The time period to complete a closed-loop process (§ 260.31(b)(4)) would berelatively short, never to exceed oneyear (to accommodate certain types ofnormal batch manufacturing operations).(See 50 FR 51265; December 16, 1985.)Reclaimed materials usually would bereturned to the original process in theiroriginal form for their original purpose(§ 260.31(b)(6)), and would then bereused by the generator (§ 260.31(b)(7)).

Tank systems would be considered aspart of a closed-loop reclamationprocess and not, therefore, as storingsolid and hazardous wastes under thefollowing circumstances:

* Secondary materials are returned,after being reclaimed, to the originalprocess in which they were generatedwhere they are reused in the productionprocess.

e Only tank storage is involved, andthe entire process through completion ofreclamation is closed by being entirelyconnected with pipes or other

comparable enclosed means ofconveyance.

• Reclamation does not involvecontrolled flame combustion (such asoccurs in boilers, industrial furnaces, orincinerators).

- The hazardous secondary materialsare never accumulated in such tanks forover twelve months without beingreclaimed.

• The reclaimed material is not usedto produce a fuel or to produce amaterial that is used in a mannerconstituting disposal.

With respect to the first condition, anissue exists regarding the types of reuseto which reclaimed materials can be putin order for the process to be considereda closed-loop. As EPA noted previously(50 FR at 51265 and n.1), the materialthat is returned after having beenreclaimed can be reused as a feedstock,as a purifying agent to removecontaminants from feedstock, and canalso be reusad for other purposes,including as a reaction medium todissolve or suspend chemicals, or as areactant to facilitate chemical reactions.To be considered as being "returned tothe original process," the reclaimedmaterial need not be returned to thesame unit operation from which it wasgenerated, but only to the same part ofthe process. (See 50 FR 640; January 4,1985.) In addition, if the same material isreused in a number of productionoperations at an integrated plant, andthe secondary material is reclaimed in acommon reclamation operation, thereclaimed material can be returned toany process which originally used thematerial. (The regulatory language hasbeen modified to clarify this last point.)

A requirement of the exclusion is thatthe reclaimed materials be returned forreuse in the production process. Byproduction process, the Agency intendsto include those activities that tiedirectly into the manufacturingoperation or those activities that are theprimary operation at an establishment;it does not include ancillary orsecondary activities that are carried outas part of the total activities at thefacility.

Commenters argued that, based on theabove definition, solvents used ascleaning agents in dry cleaningoperations would not qualify, nor wouldmaterials that are used to cleanequipment (i. e., in degreasingoperations) In response to thesecomments, EPA believes that solventsreturned for use as cleaning agents indry cleaning operations will beconsidered to be reused in theproduction process (as describedearlier) since they are used as the basicraw material in the process (in this case,

cleaning). On the other hand, materialsused to clean equipment (for example,solvents returned and reused asdegreasers) are not normally consideredto be reused in a production process.The solvents do not contribute directlyto the production process, but ratherperform an ancillary function ofcleaning. The essence of the closed-loopreclamation process (as described here)is that the act of reclamation must bedirectly related to the act of production.In the Agency's view, this is mostevidently the case when the materialreclaimed is put back to use in theproduction process. Nevertheless, theAgency is considering modifying theclosed-loop exclusion and may, in thefuture, expand the provision to apply !oany situation, including where theactivity is part of an ancillary functionof the production process, where thetank and reclamation process are part ofa closed system.

Note.-Excluded closed-loop reclamationprocesses, as described in this regulation, arenot "flow-through process tanks" forpurposes of RCRA Subtitle I, since thesetanks are not utilized in the act ofmanufacturing (see memorandum from 1.Winston Porter, Assistant Administrator,Office of Solid Waste and EmergencyResponse, to the EPA RegionalAdministrators, dated April 7, 1986,concerning the Definition of "UndergroundStorage Tank.")

With respect to the second condition,several commenters questioned whetherpipes were the sole eligible means ofconveyance. The exclusion specificallycontemplates "other comparableenclosed means of conveyance." Anysystem used to transfer the materialfrom the process to the tank and to thereclamation process, however, must be"closed." Unless there are no gaps in theprocess, the Agency does not believe itpossible to determine generically (i.e., apriori) that these operations constituteone single production process.Situations where a reclamationoperation is not literally closed can stillbe evaluated on a case-by-case basisunder § 260.31(b).

With respect to the third condition,most commenters agreed that thisexclusion should not involve controlledflame combustion. The Agencyreiterates that such processes involveeither incineration or burning for energyrecovery, operations explicitly withinthe Agency's authority (RCRA section3004(c)).

With respect to the conditionregarding duration, the 12 month timelimit is adopted from the definition ofspeculative accumulation at 40 CFR261.1(c)(8). Under this condition, persons

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would not need physically to empty thetank once a year, but rather would needto show that 100 percent of the tank'scontent was turned over within the 12month period. Examples of tank systemsthat may meet this condition are flow-through tank systems that are involvedin continuous manufacturing operations(see 50 FR 640; January 4, 1985). Inaddition, tanks involved in batchproduction could show that secondarymaterials are stored for less than oneyear through recordkeeping similar tothat which documents that secondarymaterials are not being accumulatedspeculatively. See 50 FR 636; January 4,1985.

Finally, we have added a clarifyingparagraph indicating that the exclusiondoes not apply when reclaimedmaterials are used to produce fuels orused to produce products that areapplied to the land. This principle wasestablished finally in the definition ofsolid waste rulemaking (see § § 261.2(c)(1) and (2) and 261.3(c)(2) and 50 FR 628,630, and 634; January 4, 1985), and isrestated here to avoid confusion.

Those commenters who opposedpromulgation of a generic exclusion feltthat the individual variance proceedingsprovided a preferable means ofevaluation, particularly with respect toevaluating how carefully secondarymaterials are stored before reclamation.(See § 260.31(b)(3), listing this as one ofthe factors to consider in evaluatingvariance petitions.) This factor isrelevant in determining if a secondarymaterial is a waste, because it isassumed that materials of value utilizedin production processes will be handledin a manner designed to conserve them(50 FR 654; January 4, 1985). Manycommenters from industry, in fact,indicated that they take extra handlingprecautions for these types of tanks.Secondary containment is provided formany of the tanks (since many of thesetanks are located indoors), and closedtop tanks are used to store volatiles.Comrhenters indicated that few of thesetanks were located underground.

More particularly, the extent to whichmaterials are handled to minimize lossis just one of the factors EPA mayconsider in determining if theseprocesses are deemed to be managingsolid wastes. (See 50 FR 617; January 4,1985.) The decisive factors here, in theAgency's view, are the closed nature ofthe process (hard connections frompoint of generation to point of return tothe original process), integralrelationship of these reclamation stepsto production processes, andwidespread use and economic value ofthe activity.

EPA is concerned, however, with theissue of air emissions of volatilehazardous secondary materials. Forpractical purposes, if such materialswere stored in open top tanks, theywould be uncontained EPA does notbelieve that product-like secondarymaterials would be stored in acompletely uncontained manner. (Cf. 50FR 652, n.44 (surface impoundments,another type of uncontainedmanagement, are not considered anintegral part of a hazardous wasterecycling process).) Thus, the Agencyconsidered requiring that volatiles bestored in closed top tanks to be withinthe scope of the exclusion. EPA hasdecided not to include this requirementin the final rules, however. The Agencybelieves that there are other factors andcircumstances that would prevent mostmaterials from being stored in open toptanks, especially volatile materials. Inparticular, to prevent unduecontamination from rain or dust or toprevent explosive conditions fromoccurring, most, if not all, of these tanksystems would be closed. Commenters,in fact, indicated that these secondarymaterials are stored in closed top tanks.Nevertheless, the Agency is stillconsidering whether this exclusionshould be modified to state thatvolatiles must be stored in closed toptanks. If such a provision is to be added,the Agency would propose and requestcomment before modifying thisexclusion. It should be noted that if theAgency finds a situation where highlyvolatile materials are being stored inopen top tanks and large volumes ofmaterial are being lost prior to thereclamation step, the Agency mayconsider today's exclusion to beinapplicable because secondarymaterials are not being reclaimed andreturned to the process. They are beingallowed to evaporate. Thus, such opentanks could be deemed to remainsubject to the Subtitle C regulations.

It should be noted that, under today'srule, although secondary materialsstored in closed-loop reclamationprocesses that fit within the exclusion of§ 261.4(a)(8) are not solid wastes, wastesfrom their management are solid wastes.Thus, still bottoms from solventreclamation in a closed-loopreclamation process remain solid wastesassuming no exclusion'applies foranother reason, and can be hazardouswastes if they are identified or listed. Inthis regard, the Agency notes that manystill bottoms from solvent reclamationare listed wastes, as are the residualspent solvents themselves (HazardousWastes F001-005).

Finally, EPA has decided that theexclusion provisions of § 261.4(a)(8)should become effective immediatelypursuant to section 3010(b)(1) of RCRA:the rule reduces, rather than increases,the existing requirements for personsgenerating hazardous wastes (i.e., sincepersons do not need six months tocomply and in light of the unnecessaryhardship and expense which would beimposed on the regulated community,we believe these rules should beeffective immediately).

More detailed responses to commentson the proposal to establish thisexclusion are contained in a separatebackground document entitled"Response to Comment to Closed-LoopExclusion."

B. Revisions Made Subsequent toProposal

In this section, the requirements of theproposed and final rules are reviewedand any revisions to the final rules sinceproposal (other than those discussedelsewhere in this preamble) arediscussed.

Subpart J of Parts 264 and 265 providethe tank system standards for permittedand interim status facilities,respectively. Many comments werereceived urging the Agency to eliminateany discrepancies between Parts 264and 265 and to make the two parts asconsistent as possible and appropriate.In examining this issue, the Agencyconcludes that consistency between thetwo parts is appropriate from thestandpoint of protecting human healthand the environment and would simplifythe permitting process of interim statusfacilities for both EPA and the affectedparties. Consequently, the Agency hasmade several changes and additions toPart 265 so that it is consistent with Part264.. Proposed Part 265 has also beenrecodified to make the numberingsystems of both Part 264 and 265comparable. Therefore, the numberingsystem for Part 265 of the final rulediffers from that of Part 265 of theproposed rule. Table 1 in section II.Gmay be used to cross reference Part 265in the final and proposed rules.

In developing the proposed rule, EPAassumed that the interim statusstandards would apply to existing tanksystems almost exclusively. Thus, theproposed standards in Part 264 whichapplied to new tank systems were notincluded in Part 265. However, as waspointed out in the public comments,owners/operators of new accumulationtank systems as well as replacementtank systems installed at interim statusfacilities will require standards for newtank systems. Since EPA is promulgating

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a phase-in schedule for existing tanksystems and is eliminating the ground-wdter monitoring alternative of theproposal rule, EPA expects a significantnumber of existing tank systems to bereplaced with new tank systems.Therefore, standards applicable to thesenew tank system installations arerequired and EPA is including new tanksystem standards in Part 265 that areconsistent with those found in Part 264.

These revisions as well as otherspecific changes that have been made tothe proposed standards are discussedbelow.

1. Accumulation Tank Systems (§ 262.34)

The proposed rule would haverequired that owners/operators of 90-day accumulation tank systems complywith many of the provisions of Part 265,Subpart J, including the installation offull secondary containment. Otherrequirements of the proposal for 90-dayaccumulation tank systems were:

* Response requirements for leakingtank systems, which would include:removal of the tank system from service,removal of waste from the tank system.containment of the leaked waste, andnotification of the RegionalAdministrator;

• General operating requirementswhich would include: assurance ofcompatibility of the tank contents with,the tank or its inner liner, provision of 2feet of freeboard for uncovered tanks,and provision of a waste feed cutoff orbypass system where waste iscontinuously fed to the tank;

* Closure and post-closurerequirements which would include:removal of all contamination at closureor performance of post-closure care asspecified for permitted and interim-status tank systems; and

* Inspection requirements and specialrequirements for ignitable, reactive, orincompatible wastes as would berequired for interim-status tank systems.

A number of commenters asked for aspecial exemption for 90-dayaccumulation tank systems from therequirements of Subpart 1, especially thesecondary containment requirements.Another commenter was concerned thatsince no tank system assessment wasproposed, the result would be norequirement to address tank systemsthat are leaking at the time ofpromulgation of the rule. Yet anothercommenter suggested that corrosionprotection was just as important foraccumulation tank systems as for anyother hazardous waste storage tanksystems.

As previously stated, EPA continuesto believe that there is no significantdifference with respect to the risks

posed by 90-day accumulation tanks andthe general hazardous waste tankpopulation. The Agency did not proposeto apply the entire Part 265 standards toaccumulation tanks because of itsconcerns that significant interactionbetween the owner/operator and EPAwould be needed to implement thestandards properly. However, numerouscommenters stated that the issue ofinteraction was not indeed a problem inproperly implementing many of thetechnical standards. EPA, inreconsidering its proposed standards foraccumulation tank systems, agrees withthe commenters that several of thestandards not proposed foraccumulation tank systems (e.g.,integrity tests, installation requirements,corrosion protection) can beimplemented without the need forsubstantial interaction with thepermitting authority. Furthermore, EPAbelieves that 90-day accumulation tanksystems should be able to qualify forvariances from secondary containment.Thus, the final rule requires thatowners/operators of 90-dayaccumulation tank systems comply withmany requirements of the final Part 265,Subpart 1, including:

* A one-time assessment of the tanksystem, as discussed above, includingthe results of an integrity test;

" Installation standards;" Design standards including an

assessment of corrosion potential;* Secondary containment phase-in

provisions;* Periodic leak testing if the tank

system does not have secondarycontainment; and

* Additional response requirementsto a leak, including a report to theRegional Administrator of the extent ofthe release and requirements for repairor replacement of leaking tanks.

Variance provisions that had beenprovided in the proposal only forpermitted and interim status tanksystems are available to 90-day tanksystems

The final rule does not require thatowner/operators of 90-dayaccumulation tank systems comply withthe final Part 265, Subpart Jrequirements for preparation of closureand post-closure plans, contingentclosure and post-closure plans, financialresponsibility requirements, and wasteanalysis and trial tests Unlike off-sitecommercial hazardous waste storageand treatment facilities where a widevariety of hazardous wastes aremanaged, generators generally produceand would thus store or treat wastesthat are relatively consistent in terms oftheir physical/chemical properties.Thus, EPA does not believe that waste

analysis and trial tests must beconducted by generators of hazardouswaste because of their familiarity withthe wastes that they generate. Asexplained previously in section II.H ofthis preamble, EPA is conducting areview of the requirements that areimposed on owner/operators ofaccumulation tank systems and willaddress the issues of closure and post-closure, contingent closure and post-closure, and financial assurancerequirements for accumulation tanksystems as part of this review.

This final regulation imposes noadditional requirements for 180 (270)day accumulation tanks owned oroperated by generators of between 100and 1000 kg of hazardous waste permonth. Concurrently, in today's FederalRegister, EPA is proposing revised tanksystem standards that would apply tothese generators.

2. Applicability (§§ 264.190 and 265.190)

Under the proposed rule, therequirements of Subpart J of Parts 264and 265 would have applied to ownersand operators of tank systems that storeand/or treat hazardous waste, with theexception of those tank systemsqualifying for the exemptions providedin § 264.1. Commenters to the proposedrule suggested that EPA reconsiderapplying the Subpart J standards tomany different categories of tanksystems. Among these were tanksystems storing solid hazardous wastesand temporary tank systems.

a. Storage of Hazardous WasteContaining No Free Liquids. Manycommenters recommended that tanksystems containing solid hazardouswastes, residues, dried sludges, andother nonliquid wastes be exempt fromthe Part 264 standards, especially therequirement for secondary containment,because solid hazardous wastes arerelatively immobile compared to liquidsand generally do not present a threat toground water.

There is no question that the mobilityof nonliquid solid wastes is lower thanthe mobility of liquids and gases. Forexample, liquids and gases can bemoved through conduits with relativeease while solids can be moved onlywith difficulty, requiring the use ofeither mechanical or pneumaticconveyor systems.

Mobility, however, is only oneconsideration with respect to theapplicability of the hazardous wastetank system standards to these wastes.Physical and chemical properties of thesolid are also critical considerations.The solubility and hydrophilic (affinityfor absorbing water) properties will

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determine whether the waste canreadily change physical state from asolid to a liquid.-Thus, rainwater or highwater tables could leach and dissolvesome solid wastes from poorly-constructed tank systems rendering thewastes as mobile as liquid wastes.Chemical properties are also important.Some solids, after absorbing smallquantities of moisture, can becomehighly corrosive to tank systemmaterials (e.g., inorganic salts).Additionally, a change in oxidation stateof some solid wastes can significantlyaffect solubility (e.g., a change in thevalence state of chromium in chromatesand chrome oxides from trivalent tohexavalent can transform the substancefrom insoluble to soluble].

Although EPA concludes that there ismerit to exempting some solid wastes(i.e., those that contain no free liquids)from the secondary containmentrequirements of today's regulation, withthe exception discussed below, thisexemption would have to be made on acase-by-case basis. Given the expectedsmall number of tank systems in thiscategory, EPA concludes that theappropriate relief can be given theowner or operator by the varianceprovisions built into this rule.

Tank systems storing hazardouswaste that contains no free liquids areafforded a large degree of protectionwhen located within buildings withimpermeable floors: the contents cannotflow out of the tank system, and thetank system is protected fromprecipitation or other water flowing intoit. Furthermore, if no free liquids arepresent in the waste, the potential formigration of hazardous constituents issubstantially reduced. Based on theabove factors, EPA concludes that anexemption from the secondarycontainment requirements of § 264.193and § 265.193 are appropriate for thislimited class of tank systems. Todetermine the absence or presence offree liquids, as suggested bycommenters. EPA method 9095 (PaintFilter Liquids Test], as described in"Test Methods for Evaluating SolidWastes, Physical/Chemical Methods"(EPA Publication No. SW-846), must beused.

In light of the comments regardingtank systems containing solid and othernonliquid hazardous wastes, EPAreviewed its approach to regulation ofhazardous waste tank systemsmanaging gaseous wastes. EPA has noreason to believe, nor were datasubmitted that would lead the Agency toconclude, that releases from tanksystems managing gaseous hazardouswastes will not present risks to human

health and the environment. Thus, EPAhas not revised the proposed regulationregarding this subset of hazardouswastes, and tank systems storing ortreating gaseous hazardous wastes aresubject to today's final regulation. Thevariance provisions discussedpreviously are available to owner/operators of tank systems managinggaseous hazardous wastes.

b. Temporary Tank Systems.Standards for temporary tanks were notproposed. Many commenters requestedexemption from the requirements ofSubpart J for temporary tanks used forstorage of waste in response to a leak orspill, and other temporary, unplannedoccurrences where the facility owner oroperator would need tank storage butwould not have sufficient previouswarning to provide such measures asintegrity assessments, corrosionprotection. or obtain a RCRA permit forthe tank system.

EPA has reviewed the comments andhas determined that no modificationsare required to the proposed rule.Section 264.1(g)(8) provides that therequirements of Part 264 do not applyduring immediate response todischarges or threats of discharges ofhazardous waste. Section 265.1(c)(11]provides a similar exemption for interimstatus facilities. Additionally, theRegional Administrator has theauthority under § 270.61 to issue anemergency permit in the event he "findsan imminent and substantialendangerment to human health or theenvironment." The emergency permitcan be issued to a non-permitted facilityfor any hazardous waste or to apermitted facility to allow treatment,storage, or disposal of hazardous wastenot covered by an effective permit. Theemergency permit issued pursuant to§ 270.61 must include, to the extentpossible, all applicable requirements ofParts 264, 266, and 270. The. emergencypermit will be valid for 90 days whichshould allow sufficient time for theowner/operator to arrange for adequate.storage, treatment, or disposal of thehazardous waste.

3. Assessment of Existing Tank SystemIntegrity (§ 264.191 and § 265.191)

As illustrated in Table 1, § 264.191 ofthe proposed rule addressed the designof hazardous waste tank systems, andalso required that the results of tanksystems' integrity assessments besubiitted to the RegionalAdministrator. Section 265,191 of theproposed rule addressed the assessmentand certification of existing hazardouswaste tank systems integrity at interimstatus facilities for tank systems thatwould not meet the secondary

containment requirements of proposed§ 265.193(b)-(d).

Section 264.191 of the proposed rulewould require owners and operators ofexisting and newly-installed hazardouswaste storage and treatment tanksystems to submit a written assessmentto the Regional Administrator of theirtank systems' structural integrity andacceptability for the storage andtreatment of hazardous waste. Theseassessments would be used by theRegional Administrator to make ajudgment on the acceptability of thetank system design. Under proposed§ 264.191, information that would beaddressed for all tank systems in theassessments wouldinclude (1)standards for the design andconstruction of the tank and ancillaryequipment and (2) hazardcharacteristics of the waste(s] to behandled in the system. In addition, forexisting, used, and reused tank systems,the following information would also berequired: (1) description of the tank (forexample, size, age, and material ofconstruction; (2) estimated remaininglife of the tank; (3) results of a tankintegrity test; (4) factors affectingpotential corrosion and type and degreeof corrosion protection provided; and (5)design measures to protect the tank fromvehicular traffic, floods, and seismicphenomena.

In a reorganization of the finalregulation, § § 264.191 and 265.191 nowaddress assessment of the integrity ofexisting hazardous waste tank systems.Design of new hazardous waste tanksystems is now addressed in §§ 264.192and 265.192 along with installationrequirements. Additionally, in responseto comments that the Agency shouldreassess the consistency of the proposedregulations for permitted, interim status,and accumulation tank systems,§ § 264.191 and Z65.191 have beenmodified to require similar informationto be included in tank system integrityassessments for interim status,accumulation, and permitted hazardouswaste tank systems. Also, aperformance standard has been addedto § 265.191 to ensure that the purpose ofthe integrity assessment is carried out.This objective is satisfied in the Part 264requirements by the RegionalAdministrator's independent review ofthe integrity assessment conducted onbehalf of the owner/operator.

Comments were received on a varietyof the proposed design and assessmentrequirements. Those related to thehazardous waste tank integrityassessment requirements are addressedin this section of today's preamble.

I Ill I I I I

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Several commenters questioned theneed for certifications and presenteddifferent views with respect to whetherexperts conducting the assessmentsshould be independent of the owner/operator. EPA analyzed the issue of-whether the assessment required in§ 264.191 should be conducted by aqualified registered professionalengineer and whether the registeredprofessional engineer could beemployed by the owner or operator. TheAgency believes that the one-timeassessment should be made by a personwho does not have a conflict or theappearance of a conflict of interest,Accordingly, the word independent hasbeen added to the final rule to c!arifythat employees of the owner/operatorcannot make the assessment. TheAgency's position in this regard isconsistent with other types ofcertification programs which requireassessments and certifications to bemade by independent parties. Forexample, the Subpart G-Closure andPost-Closure regulations in § 264.115require that both the owner/operatorand an independent registeredprofessional engineer certify that thefacility has been closed in accordancewith the specifications in the approvedclosure plan Additionally, the Securitiesand Exchange Commission requires thatall publicly-traded companies provideindependent audits of financialinformation. Similarly, grants issuedunder the Clean Water Act must beaccompanied by independent audits.

Several commenters also objected tothe 0.05 gallon per hour leak teststandard as being unmeasurable orarbitrary. Others supported thisproposed leak testing standard. Asdiscussed previously, the state-of-the-artof leak testing procedures is such that itis not possible to measure reliably forleaks to this degree of accuracy,Therefore, the final rule for both§ 264.191 and 265.191 removes the leaktest standard of 0.05 gallons per hour.EPA will continue to study the entireissue of leak detection and plans topublish guidance in the future regardingleak detection methods and procedures.In the meantime, EPA has includedgeneral performance standards in thefinal regulation that require that a leaktest be capable of accounting fortemperature fluctuations, tank enddeflection, vapor pocket effects, andwater table effects. The factors wereadded based on comments on the June26, 1985 proposed hazardous waste tanksystem regulations. EPA's priorknowledge of potential problemsassociated with tank tightness testing,and on the OTS survey, which found

that failure to take account of theseeffects rendered many commercial tanktests extremely unreliable. In .addition,§ 264.193 and § 265.193 require that aqualified registered professionalengineer review and certify that theselected annual leak testing method(s) isin accordance with sound andacceptable engineering practices for thetank system being evaluated. Foradditional discussion of this issue, referto section IV.B.5.c of this preamble.

EPA proposed that tank integrityassessments be conducted within 6months of the effective date of the rules.Several concerns were voiced bycommenters regarding the number ofqualified leak testers, the availability offunds to perform the assessment, theinterruption of facility schedules (yearlyshutdowns for maintenance are. oftennecessary), and the amount of timenecessary for compliance for largefacilities. Some commenters wereconcerned with the inadequacy of tankintegrity testing methods, and asked foran extension or elimination of the first-time inspection requirement for interimstatus tank systems based on this factoralone.

EPA has further evaluated the six-month deadline imposed for the one-time assessment. The Agency concludesthat there are potential problemsassociated with this requirement. Basedon the results of the OTS §tudy ofavailable tank system tightness testingmethods, it is likely that availablecommercial methods will need to bemodified to meet the generalperformance standards contained in thefinal regulation. Additionally, it will benecessary to test the accuracy of thenew methods and to train personnel inthe use of the new methods. For thesereasons, the final rule establishes adeadline of twelve months for the one-time assessment. EPA believes that thisextension will afford sufficient time toensure that qualified methods andpersonnel are available to conductintegrity assessments of hazardouswaste tank systems.

The proposed rule in § 264.191 wouldhave required that, as part of theassessment of the adequacy of thedesign of an existing system, anestimate of the remaining useful life ofthe tank system be made. Commentersexpressed the concern that anestimation of this kind would besubjective and thus of questionablevalue. While disagreeing with thecommenters that estimates of this natureare of little value, the Agency is nowadopting a phase-in approach forsecondary containment and thatperiodic tank system integrity

assessments be made prior to the phase-in. Thus, EPA concludes that therequirement to estimate the tanksystem's remaining useful life is nolonger necessary. Instead, § § 264.191and 265.191 require that the age of thetank system be documented for use indetermining when secondarycontainment will be required because ofthe phase-in requirements of this finalregulation.

4. Design and Installation of New TankSystems (§ 264.192 and § 265.192)

As illustrated in Table 1, § 264.191 ofthe proposed rule would have addresseddesign and § 264.192 would haveaddressed installation of new hazardouswaste tank systems at permittedfacilities. The proposed Part 264standards were formulated to ensurethat a tank system is acceptable forstoring or treating hazardous wastes andalso addressed the handling andinstallation of new tank systems,including backfill requirements,tightness testing requirements beforeplacement into service, corrosionprotection requirements, and installationsupervision requirements.

In today's regulation, both design andinstallation of new permitted hazardouswastestank systems are addressed in§ 264.192. As pointed out bycommenters, the proposed rule wasdeficient in that it did not specifyrequirements for the design andinstallation of new tank systems atinterim status facilities. As previouslydiscussed, new hazardous waste tanksystems may be installed by owner/operators of interim status facilities andby generators. Thus, this final rule nowaddresses design and installation of newhazardous waste interim status andaccumulation tank systems in § 265.192.As suggested by commenters, § 265.192is consistent with § 264.192 in itstreatment of new hazardous waste tanksystems.. For the purpose of today's regulation,the term "new tank system" means notonly newly-manufactured tank systemsthat will be put into service for the firsttime but also those other tank systemsthat even if in existence and in use priorto the promulgation date of today'sregulations are then reinstalled and usedas replacement tank systems for existinghazardous waste tank systems.Likewise, an existing tank system that isnot being used for the storage ortreatment of hazardous waste, but isthen put into service or converted to useas a hazardous waste storage ortreatment tank system subsequent to thepromulgation date of today's regulationis considered to be a new tank system.

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One commenter noted the potentialeffect of frost heave on tank systems innorthern States and suggested a changein the design requirements to cover thiscontingency. EPA agrees that frostheave, where applicable, is an importantfactor that needs to be taken intoaccount in the design of a tank systemand is thus adding the consideration ofsuch to the items that need to beaddressed in the design standards in§ 264.191 and § 265.191.

Sections 264.191 and 264.192 of theproposed rule would have required thatthe type and degree of corrosionprotection needed to ensure the integrityof new hazardous waste tank systemsbe determined by a corrosion expert andthat the installation of any cathodicprotection system be supervised by acorrosion expert. Additionally, § 264.192of the proposed rule would haverequired an assessment of the need forcorrosion protection measures forexisting tank systems.

Regarding the corrosion protectionissue, one commenter suggested thatmore flexibility was needed inresponding to corrosion threats. Othercomments expressed reservations aboutthe feasibility and necessity ofretrofitting existing tanks with corrosionprotection devices. Another commentersuggested that double-walled tanks beexempted from the corrosion protectionrequirements.

As discussed previously, EPA isrequiring that all existing tank systemsbe provided with secondarycontainment if they are found to beleaking or by the time the tank systemreaches 15 years of age. The 15 yeartimeframe represents the approximatemedian time to failure for thoseunderground steel tank systems thatwere the subject of studies discussedpreviously in this preamble. EPA hasselected this approach on the basis thatunderground steel tank systems are theonly tank systems for which reliabledata are available. For this reason, theAgency believes that a requirement toprovide existing tanks with corrosionprotection before phase-in of thesecondary containment requirements oftoday's final rule is redundant becausethe basis of the phase-in of secondarycontainment accounts for the fact thatmost hazardous waste tank systemscurrently in use do not have corrosionprotection. Therefore, EPA has modifiedthe final rule and no longer requires thatexisting primary tank systems beretrofitted with corrosion protectionprior to the mandatory phase-in ofsecondary containment.

EPA also believes that the corrosionprotection measures proposed representthe spectrum of the technology that is

currently available, and are consistentwith NACE recommended practices.Therefore, EPA believes that thecorrosion protection requirements asproposed are sufficiently flexible andcapable of meeting the corrosionprotection needs of hazardous wastetanks. The Agency also believes thatdouble-walled tanks that areconstructed of metal, or that have metalcomponents, should not be exempt fromthe requirements to provide adequatecorrosion protection measures. EPAbelieves that it is important to ensurethe integrity of the secondarycontainment structure so that it will beable to provide the function that it isintended to perform (i.e., containment sothat the interstitial monitoring device iscapable of detecting releases).

A primary function of the secondarycontainment system is to provide ameans for accumulating leaks from thestorage or treatment tank system so thata leak can be detected by leak detectionmethods before its release to groundwater or surface water. Therefore, it isimportant that the integrity of thesecondary containment system bemaintained because a breach in thesecondary containment system can leadto unreliable leak detection and result insubsurface releases from underground,inground, or onground tank systems.Also, failure of the secondarycontainment system can lead tointrusion of ground water into theinterstitial space between the tank andsecondary containment systems withconsequent potential for corrosion of theentire system. For these reasons, EPAbelieves that corrosion protectionsystems should be installed forsecondary containment systemsconstructed of steel or other materialssubject to corrosion.

For the same reasons discussedpreviously, EPA has revised Parts 264and 265 so that all interim status andpermitted, as well as existing and newtank systems, are more consistentlymanaged. EPA believes that interimstatus and permitted tank systemsshould be subject to the samerequirements since there is noinformation that would suggest that thethreats to human health and theenvironment differ for these two typesof tank systems. On the contrary, therisks posed by interim status andpermitted tank systems would be similarunder similar conditions (e.g., tank size,material stored or treated, hydrogeology,proximity to a drinking water source).Performance standards have beenadded to § 265.192 to ensure that thepurposes of the design and installationrequirements are achieved. Thisobjective is satisfied in the Part 264

requirements by the RegionalAdministrator's independent evaluationof the design of new hazardous wastetank systems.

5. Containment and Detection ofReleases (§ § 264.193 and 265.193)

Secondary containment is the keyelement in EPA's strategy to ensure theproper management of hazardouswastes stored and treated in tanksystems. Based on EPA's studies, it islikely that over time tank systems willexperience failure. As discussedpreviously, secondary containment withinterstitial monitoring ensures that afailure of the tank system will bedetected before there is a release to theenvironment.

Several commenters urged that moretime be allowed for installing secondarycontainment systems than the one yearthat would have been allowed in theproposed regulations, especially forfacilities with multiple tanks or thoselocated in areas where the availabilityof construction equipment or qualifiedpersonnel is limited. As discussedpreviously, in a substantive change fromthe proposed rule, EPA has decided, inthe final rule, to allow a phase-inschedule for installing secondarycontainment systems that is based, inpart, on the age of the tank systems.Therefore, except for those tank systemsthat would require secondarycontainment in the relatively near termdue to advanced age (i.e., tank systemsthat are approaching 15 years of age),considerable time is available forowner/operators to provide secondarycontainment for their existing tanksystems. For those tank systems thatmust be provided with secondarycontainment in the near term, for thereasons discussed below, in no instancewill secondary containment be requiredto be installed for tank systems shownto be non-leaking by tank systemintegrity assessments or by other meanssooner than two years from thepromulgation date of this regulation.However, leaking tank systems must betaken out of service promptly upondetection of the leak and equipped withsecondary containment prior to beingreturned to service. EPA expects thatowner/operators will use back-up tanksystems or some form of temporarystorage while servicing a leaking tanksystem.

In evaluating comments on thissubject, EPA relied, in part, on a studyprepared for the proposed LandDisposal Restrictions Rules for Solventsand Dioxins (51 FR 1602; January !4,1986). The purpose of this study ("TimeRequirements for the Siting, Permitting

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and Construction of New HazardousWaste Treatment Facilities", December1985] was to determine the time requiredto plan, design, permit, construct, andstart up twenty-three different wastetreatment technologies.

This study identified five majorcritical path activities (planning, design,bid solicitation/evaluation, construction,and start up) in addition to the EPApermit approval activity. Several ofthese twenty-three treatmenttechnologies, such as neutralization orprecipitation, involve equipment that isidentical to or similar to the equipmentused in the tank systems covered bytoday's regulation. The study revealsthat the minimum time required to plan,design, solicit and evaluate bids,construct, and start up a small chemicaltreatment system would be from 12 to 17months, excluding the time for permitapplication approval. For a large,chemical treatment system, about 25 to29 months would be required.

These schedules included estimates ofthe time required for site selection,environmental assessment, and Part Bpermit application preparation. EPAbelieves, therefore, that the amount oftime required to provide secondarycontainment for existing hazardouswaste tank systems will be less than the29 month period identified for largesystems, but is likely to take more thanthe one year period specified in theproposed rule. Thus, the final ruleallows owner/operators V minimum oftwo years to provide secondarycontainment for existing hazardouswaste tank systems shown to be non-leaking by tank integrity assessments.This will allow ample time to installsecondary containment systems.

a. General and Specific Requirementsfor Tank Systems. Sections 264.193 (b)and (c) and 265.193 (b) and (c) of theproposed rule would define the generalperformance standards that must beachieved by secondary containmentsystems. They were as follows: (1) thedesign of the tank system must take intoaccount normal climatic, hydrological,and operating conditions; (2) materialsof construction of the secondarycontainment system must be compatiblewith the wastes being handled in thetank system; (3) the secondarycontainment system must be supportedon a properly designed and installedfoundation or base; (4) the system mustbe provided with a leak detectionsystem designed to detect the presenceof hazardous wastes in the secondarycontainment system within 24 hours ofentry of liquid into the system; (5) thedesign must provide for drainage,collection, and removal of the wastes;

(6) the system must be designed andoperated to contain 110 percent of thedesign capacity of the largest tankwithin its boundary; and (7) the systemmust be designed and operated toprevent run-on or infiltration of outsidewater sources or precipitation unless theliquids removal system is designed tohandle and dispose of such sourcesproperly.

Numerous technical comments weredirected at these standards, especiallyto point out cases and situations wherethe standards were believed to conflictwith specific designs or currentpractices. The corresponding standardsof the final rule, found in § § 24.193 (c)through (e) and 265.193 (c) through (e),remain substantially as proposed, withthe exceptions discussed below.

The proposed rule would require that,in conjunction with secondarycontainment, a leak detection system bedesigned and operated to detect thepresence of any release of hazardouswaste or accumulated liquid within 24hours of entry into the secondarycontainment system. Many commentersexpressed concern over the requirementthat the detection system be able todetect a leak within 24 hours. Based onfurther evaluation, EPA agrees that,depending on type of detector, wastecharacteristics, and migration timethrough backfill materials, the 24-hourdetection criterion may not beachievable in some situations. On thisbasis, the final rule has been amendedto allow a leak detection system thatwill detect a release "within 24 hours orat the earliest practicable time" if it canbe demonstrated that existingtechnologies or site conditions will notallow detection of the release within 24hours. In no instance would the Agencyconsider a leak detection system to beadequate if it would allow the release toescape from the secondary containmentsystem before being detected.

EPA had originally proposed a 110-percent capacity requirement for thesecondary containment system,intending that this requirement wouldapply to vault and liner systems.Commenters pointed out that theinterstitial volume of a double-walledtank, an acceptable form of secondarycontainment, would not be capable ofmeeting the 110-percent capacityrequirement. It was not the Agency'sintent at proposal to apply this capacitystandard to double-walled tanks. Thus,the organization of § 264.193 (b) through(d) (and the corresponding sections ofPart 265) has been changed so thatcapacity of the secondary containmentsystem is specified only for vault andliner systems.

Many commenters stated that theproposed standards that would require110-percent design capacity wereexcessive. Many existing industrystandards and regulations, such as thosepublished by the National FireProtection Association, specify thataboveground secondary containmentsystems be capable of containing 100percent of the storage tank volumes.Several commenters also explained thatthey have installed secondarycontainment in accordance with Stateregulations that specify 100 percent ofthe tank design capacity. The Agencyagrees that 100 percent secondarycontainment capacity is sufficient tocontain even catastrophic releases fromtank systems. Therefore, the final rule isamended to require that vault and linersystems contain 100 percent of theactual volume of the largest tank withintheir boundaries.

Section 264.193(c) of the proposed rulespecified that secondary containmentmust include one or more of the threemost common types of secondarycontainment available: external liners,vaults, and double-walled systems.Equivalent devices would be allowableif approved by the RegionalAdministrator. This requirement wasnot intended to endorse any particulartype of containment system overanother. If properly designed, installed,and operated, each of the methods isexpected to provide adequate protectionof human health and the environment.The requirements of this section of thefinal rule. therefore, remain the same asin the proposed rule.

EPA solicited comments on thefeasibility of allowing the use of asynthetic membrane liner withinterstitial monitoring installed insidethe primary containment device as analternative means of achievingsecondary containment. The commentsthat were submitted on this subjectpresented opposing opinions on theacceptability of this alternative as anequivalent form of secondarycontainment. The Agency has very littledata regarding the current use of andreliability of internally fitted membraneliners. Additionally, EPA has concernsabout the ability to maintain aninterstitial space between the membraneliner and the tank and the consequentimpact on the ability to reliably detectreleases from the membrane liner. Sinceno additional data were offered bypublic commenters, at this time, EPA isunable to evaluate this alternativeapproach to secondary containment.Therefore, the final regulation does notspecifically allow the use of amembrane liner as an acceptable

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method of secondary containment. It ispossible, however, that an owner/operator's specific design will beapproved by a Regional Administratoras a system equivalent to secondarycontainment with interstitial monitoring.

Section 264.193(d)(1) of the proposedrule would provide design standards forexternal liners used for secondarycontainment. It specified that liners areto be free of cracks or gaps and installedto cover all surrounding earth likely tocome into contact with the waste if arelease occurred. It explained thatexternal liners may be used to containreleases from aboveground, inground,and underground tanks and that ownersand operators who use an external linerto provide secondary containment mustensure that the liner provides acomplete envelope that will preventboth lateral and vertical migration ofwastes from the containment system. Itrequired that a leak-proof connectionbetween the tank and pipingcontainment systems must be providedand that compatibility between the linerand the wastes to be handled must beensured so that the integrity of the linerwould be maintained.

Some commenters suggested thatcertain specific liner performancecriteria be incorporated into thestandards. In order to provide sufficientflexibility in selecting an appropriateliner material and given the. ever-improving technology for liner materials,the Agency has chosen not to establishspecific liner performance criteria at thistime. EPA believes that such criteria arebest discussed in a guidance document.Due to the important role of liners foruse in landfill, surface impoundment,and waste pile design and operation,substantial information has beengathered by EPA on the subject of linerperformance. The Agency will publishavailable information on specific linerperformance in a guidance document tobe issued prior to the effective date ofthis regulation.

No other substantive comments werereceived on these proposedrequirements and they remain in thefinal rule under § 264.193(d)(1). Identicalrequirements have been added to thefinal rule under § 265.193(d)(1) in orderto help maintain a consistent approachbetween interim status and permittedstandards.

The standards in § 264.193(d)(2) of theproposed rule would have required thata vault system be constructed so that itis liquid-tight; that is, it must provide acontinuous structure with leak-proofjoints. Water stops or seals on all jointsmust be chemically compatible with thewaste being stored or treated. Theproposed rule would require that

concrete vaults, one of the mostcommon types of vault systems now inuse, be lined with a nonporous,impermeable interior coating that iscompatible with the waste being stored,on the basis that concrete is porous andsusceptible to cracking. The proposedrule would also require that the externalsurface of vault containment structuresbe provided with a moisture barrier toprevent water from being absorbed bythe concrete and entering the interior ofthe secondary containment area.

Several commenters recommendedthat the requirement for interior coatingbe amended to require interior coatingonly where it is necessary to prevent themigration of waste through the concrete;others recommended that it beeliminated entirely. Further review ofthis issue by EPA concludes thatconcrete, as a generic term, can varywidely in specific composition andcharacteristics, making it extremelydifficult to establish a specification forconcrete that would ensure resistance tothe wide range of hazardous materialsthat may come in contact with a vaultsystem. Thus, some type of protectiveinternal coating or liner is needed tomaintain the integrity of concrete vaults.The Agency has, however, expressedthis requirement in terms of a broadperformance standard so as not topreclude operating flexibility, and thusis not recommending any specific typeof liner coating or liner as at-proposal.

Comments concerning the requirement'for an exterior moisture barrier forvaults stated that the moisture barriershould not be required, except wherevaults that are in contact with the soil orin locations where potential for ground-water infiltration exists. Othercommenters raised the concern thatretrofitting an exterior moisture barriercould be costly relative to the benefitsachieved. EPA reevaluated the proposedrequirements and concludes that the useof moisture barriers to preventinfiltration of ground water into anunderground or inground vault shouldbe required only when the vault issubject to hydraulic pressure. This is acondition that is most likely to existwhen a vault is completely or partiallysubmerged below the water table atsome time. EPA has also determinedthat other methods are currentlyavailable that could reduce or eliminatewater infiltration (such as well-pointinstallation, subsurface drain tiles, orslurry walls). Thus, EPA has modifiedthe final rule to require that all vaultsystems, both new and existing, beprovided with an external moisturebarrier or be otherwise designed oroperated to prevent migration of

moisture into the vault if the system issubject to hydraulic pressure.

A significant concern addressed in theproposed rule was the risk of fire orexplosion in vaults. Section264.193(d)(2)(iii) of the proposed rulewould require vaults containing tanksstoring or treating ignitable wastes to bebackfilled to minimize the possibility offires or explosions. Several commentersobjected to the backfilling requirementbecause: (1) fire protection codes andpractices may not allow backfilling inthe case of ignitable substances; (2)backfilling prevents visual inspection ofthe vault interior and tank exteriorsurfaces; and (3) the cost of remedialaction is increased in the event of arelease. Upon further consideration ofthis issue, EPA concludes that theexplosion hazard associated with vaultsis small and that there are relativelyinexpensive and reliable equipment andinstrumentation systems to reduce therisks of explosion. These systemsinclude preventative measures such asequipment grounding and the use ofelectrical equipment meeting explosion-proof service. In addition, suppressionsystems can also be installed which usean explosive vapor detector, andprovide an inert flooding agent such as afluorochlorohydrocarbon to flood thevault automatically if explosiveconditions exist. The final rule thuseliminates the backfilling requirementfor vault systems as the only means toprotect against fire hazards andsubstitutes the requirement thatsecondary containment vaults for tanksstoring or treating ignitable wastes mustbe provided with a means to protectagainst the formation and ignition ofexplosive vapors within the vaultsystem. Backfilling would be anacceptable method. Also, because somereactive wastes can lead to theformation of ignitable or explosivevapors, today's regulation requires thatsecondary containment vaults forstoring or treating reactive wastes thatmay lead to the formation of ignitable orexplosive vapors must also be providedwith a means to protect against theformation and ignition of explosivevapors within the vault system.

The standards in § 264.193(d)(3) of theproposed rule would require thatdouble-walled tank systems be designedas integral structures that arecompletely self contained, withinterstitial leak detection monitoring. Itwould allow the use of liquid, vacuum,or pressure-type detection systems. Itwould require that corrosion protectionbe provided for metal double-walledtanks if it is determined to be necessary.As previously discussed in section

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IV.B.4 of this preamble, EPA believesthat corrosion protection of double-walled tanks is necessary, contrary tothe opinion of one of the commenters.The final rule does not change thestandards for double-walled tanks,except, as discussed previously, tomodify the proposed provision requiring110 percent secondary containmentvolume.

In § 264.193(e) and § 265.193(d) of theproposed rule, EPA would requiresecondary containment for all newancillary equipment as well as for theancillary equipment of all existinghazardous waste storage and treatmenttank systems that did not choose toimplement a ground-water monitoringprogram. This requirement would haveapplied to both aboveground andunderground piping systems.

Many commenters supported theapplication of secondary containment tothe ancillary equipment or mostancillary components. Commentersnoted, however, that the overwhelmingmajority of leaks from the ancillaryequipment occur in certain componentsof piping systems, and not in the moreextensive sections of straight-run pipingwith welded connections. EPA'sreevaluation of the available data onreleases from tank systems shows thatleaks and ruptures from abovegroundpiping systems are primarily associatedwith certain components such asflanges, valves, and piping connections,not straight runs of piping with weldedconnections, probably because theyoften employ pipe thread or gasket-typeseals and are more susceptible tostresses than straight-run welded piping.Technologies that are both cost-effectiveand reliable are available to providecontainment for many ancillaryequipment components. For example,local jacketing provides effectivesecondary containment for componentssuch as flanges, valves, and fittings, andcan be provided with leak detectionequipment.

The Agency concludes that thepotential for leakage from straight runsof aboveground welded piping, seallesspumps, and pressurized abovegroundpiping equipped with automatic shut-offdevices is substantially lower than forother components of the ancillaryequipment systems. Thus, therequirements of proposed § 264.193(e)and proposed § 265.193(d) have beenmodified in today's final rule to excludethe requirement of secondarycontainment for aboveground piping(exclusive of flanges, joints, and valvesunless they are sealless and welded tothe piping), sealless or magnetic pumps,and pressurized aboveground piping

systems with automatic shut-off devicesthat can be visually inspected for leakson a daily basis. The final regulation (in§ 264.195 and § 265.195) requires thatthese ancillary equipment systems bevisually inspected on a daily basis toensure that leaks are not occurring.

The final rule requires secondarycontainment for underground pipingsystems, including straight runs ofunderground pipe, because of thepotential for failure caused by corrosionand/or the inability to detect releasesfrom the underground piping systems.

b. Deletion of Ground-WaterMonitoring Alternative. As discussed insection III.B.6.a of this preamble, theAgency has removed the provisions ofproposed § 264.193(f) and § 265.193(e)that gave owners/operators the optionof instituting a ground-water monitoringprogram in lieu of secondarycontainment. Instead, owner/operatorsof all hazardous waste tank systemsmust either provide full secondarycontainment or obtain a variance to thesecondary containment requirements.However, as explained previously, thetechnology-based variance is notavailable on the basis of ground-watermonitoring technology because theoverall strategy for regulating hazardouswaste tank systems is based on theprevention of contamination of groundwater by releases from tank systems.

c. Leak Testing and Tank SystemIntegrity Assessment Requirements. In§ 264.193(h) and § 265.194(d) of theproposed rule, EPA would require allunderground tank systems that do nothave secondary containment to be leaktested semiannually. The leak testing ortank system tightness testing methodselected was required to detect leaksequal to or greater than 0.05 gallons perhour. Many commenters expressed aconcern that the accuracy requirementmay not be achievable by commercially-available tank system tightness testingtechniques. Some commenters felt thatthe accuracy standard should be basedon tank size, while others stated thatthere is not enough good field data toestablish a standard at all. In responseto comments, EPA has reconsidered thereliability of tank system tightness testmethods. While some techniques may becapable of achieving the 0.05 gallon perhour accuracy threshold in specificinstances, EPA concludes thatvariations in tank systemcharacteristics, operating procedures,calibration and maintenance of leakdetection devices, and the level ofexperience and proficiency of testpersonnel may not allow achievement ofthis accuracy on a consistent basis.

Many factors can affect tank systemtightness testing accuracy, includingtemperature, barometric and hydrostaticpressure variations, tank size anddesign, physical characteristics of thewaste (e.g., viscosity, volumetriccoefficient of expansion, and uniformityof the liquid waste), variations instructural support provided by soil or fillcharacteristics, and leak detectorcharacteristics. An example illustratesthe volumetric sensitivity of tank systemtightness tests to temperature for a tankstoring a waste hydrocarbon solvent. Atemperature rise of only 0.02°F in onehour would mask a leak of 0.084 gallonsper hour in a 6.000-gallon tank storingthe waste solvent. On the other hand, aleak of 0.05 gallons per hour in a 4-inchdiameter pipe experiencing the sametemperature change can be detected in apipe up to 9,000 ft long. Because smallervolumes are associated with piping,integrity tests are much more accuratefor piping.

EPA believes that the level ofaccuracy attainable by leak testingmethods must be reviewed periodicallyas the technology improves. In this finalrulemaking, EPA has decided not tospecify a minimum acceptable accuracyrequirement for hazardous waste tanksystem tightness testing. Rather, EPAhas chosen to include in Parts 264 and265 general performance standards toensure that the leak testing method iscapable of properly compensating forwater table effects and temperatureeffects and to address the problemsposed by tank end deflections and vaporpockets. EPA is currently conductingresearch on the effectiveness of tanksystem tightness testing technologies atthe EPA Research Facility in Edison,New Jersey. The Agency hopes to beable to use the information gained fromthis research to recommend the use ofspecific methods of tank systemintegrity testing. However, it is unlikelythat these methods will ever be asreliable as leak detection methodsemploying secondary containment andinterstitial monitoring, in part because itis unlikely that tank tightness testingcan be conducted on a routine basis(e.g., daily) because of the high costs ofso doing.

In a modification to the proposed rule,EPA will allow owner/operators ofunderground tanks that can be enteredfor inspection to conduct internalinspections or other tank integrityassessments, including tank tightnesstesting, rather than to specify that tanktightness test methods must beemployed. The Agency is making thischange, which was strongly supportedby commenters, to ensure that owner/

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operators are able to use the mostreliable methods available to assess theintegrity of their hazardous waste tanksystems. In certain instances, it isprobable that internal inspection orsome other form of integrity assessmentmay be shown to be preferable to tanktightness testing.

Commenters also addressed the issueof leak testing frequency. Most felt thatthe semi-annual leak testing requirementwas excessive. Specific points raisedwere that (1) a sufficient number ofqualified leak-testing personnel do notexist, (2) tank testing should bescheduled to coincide with annualshutdowns for maintenance and repair,and (3) leak testing every six monthsrepresents a significant increase inoperating costs.

In this final rule, leak testing will beused during the period of phase-in ofsecondary containment to identifyleaking tank systems. As discussedpreviously, those systems found to beleaking will be taken out of serviceimmediately. Underground componentsof tank systems, or components forwhich a leak occurred in an area thatcannot be visually inspected will beprovided with secondary containmentprior to being placed back into service.The final rule requires that such tests beconducted on an annual basis. Leaktesting methods that meet theperformance standards included intoday's final rule will be able to detectreleases in the range of 0.1 gallons perhour that develop during the period ofthe phase-in of secondary containment.Once secondary containment is phased-in, risks associated with leaks that areundetectable by present leak testingmethods will be eliminated.

Proposed §§ 264.193(g)(9)(ii) and265.193(e) addressed tank integritytesting requirements for owner/operators of inground and aboveground(including onground) hazardous wastetank systems not equipped withsecondary containment with interstitialmonitoring (i.e., those owner/operatorselecting to comply with the requirementsof the proposed ground-watermonitoring alternative). These proposedstandards would have required owner/operators to assess the integrity of thetank system in the event that there was,at any monitoring well, a statistically-significant increase in the parameters orconstituents measured as part of theground-water monitoring alternative.Additionally, as explained previously,proposed § § 264.191 and 265.191 wouldhave required an initial assessment oftank system integrity, includinginground and aboveground tanksystems.

As the secondary containmentrequirements of today's regulation arebeing phased-in over a period of time,EPA believes that it is important toassess the integrity of hazardous wastetank systems during the phase-in period.Therefore, today's regulation requires in§ § 264.193 and 265.193 that periodicintegrity assessments be conducted forcompletely aboveground, onground, andinground hazardous waste tank systems,as well as for the underground tanksystems discussed above. Integrityassessments of ancillary equipmentmust be conducted annually. Availablemethods include the various pipe systemtightness tests and, to a limited extent,visual inspections.

For permitted tanks other than non-enterable underground tanks, a scheduleand procedure must be developed duringthe permitting process for assessing theoverall condition of the tanks. In theabsence of a permitting processapplicable to interim status andaccumulation tank systems, EPA hasdetermined that an internal inspection'or other tank integrity examination thataddresses cracks, leaks, corrosion, anderosion must be performed at leastannually for tanks other than non-enterable underground tanks. Asexplained previously, for non-enterableunderground hazardous waste tanksystems, leak testing procedures arerequired that meet the generalperformance standards established intoday's regulation.

d. Variances from SecondaryContainment. Sections 264.193(i) and265.193(f) in the proposed rule provideda variance from all or part of thesecondary containment requirements ifthe owner or operator coulddemonstrate to the RegionalAdministrator that the location of thetank system and alternative design andoperating practices would preventhazardous waste from reaching groundor surface waters at any future time. Asexplained previously in sectionIII.B.5.b.ii, the final rule, in § 264.193(g)and § 265.193(g), allows hazardouswaste tank system owner/operators toseek both technology-based and risk-based variances from secondarycontainment requirements based oneither (1) a demonstration of nomigration of hazardous wasteconstituents beyond the zone ofengineering control or (2) ademonstration of no substantial presentor potential hazard to human health andthe environment.

As with all variances, the burden ofdemonstrating that a variance isappropriate remains with the applicant.If the Agency Is not persuaded that the

information provided makes thenecessary demonstration with greatcertainty, the variance will be denied.

(i) Technology-based variance. Thecriteria that the applicant must usewhen preparing requests for atechnology-based variance from thesecondary containment requirements ofthis regulation are specified in§ 264.193(g)(1) and § 265.193(g)(1).Essentially, the applicant must be ableto demonstrate that his alternativedesign and operating practices togetherwith location characteristics willprevent the migration of hazardouswaste or hazardous waste constituentsinto the ground water or surface waterat least as effectively as secondarycontainment with leak detection. Thekey element of this variance mechanismis the ability of the owner/operator tocontain releases from his tank systemwithin an area under his control that,upon detection of a release, can bereadily cleaned up prior to the release ofhazardous waste constituents to groundwater or surface water.

The Agency will require that theapplication for variance include acomplete and thorough demonstrationthat the alternative system will provideequal prevention of migration as thatprovided by secondary containmentwith interstitial monitoring. Theapplication will undergo rigorous reviewby the Regional Administrator to ensurethat the applicant makes thedemonstration with great certainty.Owner/operators are cautioned thatEPA has evaluated available releasedetection systems as a part of thisrulemaking and has determined thatinventory monitoring, tank tightnesstesting, and unsaturated zonemonitoring are hot as reliable at presentas secondary containment withinterstitial monitoring. However, EPA isaware that technology could improve orthat site-specific conditions may exist atsome locations that might enableperformance equivalent to secondarycontainment with interstitial monitoring.Therefore; the Agency has provided amechanism that allows owner/operatorsof hazardous waste tank systems toseek a technology-based variance fromthe secondary containmentrequirements of this regulation.

This variance mechanism is designedto allow an owner/operator theopportunity to demonstrate that aninnovative tank system design or leakdetection method will be capable ofpreventing contamination of groundwater or surface water or that a leakdetection method not believed to begenerally reliable (e.g., unsaturated zonemonitoring) will be reliable forhis

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hazardous waste tank system. Theapplicant must take into considerationthe nature and quantity of the hazardouswaste, the proposed alternative designand operating conditions, thehydrogeologic setting, and all otherfactors te.g., depth of soil underlying thetank system, soil properties includingporosity and likely degree of saturationduring operation of the tank system, andfluid or constituent viscosity] thatinfluence the mobility of the hazardouswaste constituents and the potential fortheir migration. The applicant must alsodemonstrate the reliability andcapability of his alternative systemdesign (and release detection method)and operating practices in detectingreleases and in preventing the migrationof hazardous waste constituents toground water and surface water.

If a technology-based variance isgranted, the Regional Administrator willsubstitute a set of requirements in placeof secondary containment that willensure that the system for which thevariance has been granted is maintainedand operated in a manner than willprevent the migration of hazardouswaste to ground water or surface water.If hazardous waste does reach groundwater or surface water, the variance willbe revoked.

The Agency discourages thesubmission of technology-basedvariance applications in those situationswhere secondary containment isobvious!y provided. For example, fortank systems located inside buildings,the building floor, if appropriate bermsare constructed, would serve as part ofthe secondary containment system. TheAgency also may deny the variance ifthe application is incomplete.Additionally, the Agency discouragesthe submission of unpersuasiveapplications. For example, earthenberms are generally not capable ofpreventing the migration of hazardouswaste or hazardous waste constituentsand would not qualify for a variance.

If a release of hazardous waste occursat a tank system operating under thetechnology-based variance, the owner oroperator must comply with responsemeasures required by §§ 264,193 and265.193. The response measures that willbe applicable to releases fromhazardous waste tank systems granted atechnology-based variance will varydepending on whether migration hasoccurred outside the zone of engineeringcontrol established in the varianceprocess.

If the release is contained within thezone of engineering control, theresponses that are required in § § 264.196and 265.196 for releases to a secondarycontainment system would be

applicable. The owner or operator muststop the flow of hazardous waste intothe tank system and promptly, within 24hours if possible, empty that portion ofthe leaking tank system at which theleak or spill has or is occurring in orderto prevent any additional release ofhazardous waste and to allowinspection and repair to be performed.The owner/operator must also preventthe migration of hazardous waste orhazardous waste constituents beyondthe zone of engineering control toground water or surface water.

In addition, the owner or operatormust decontaminate or remove thecontaminated soil so that releases fromthe hazardous waste tank system can bedetected and responded to in a mannerconsistent with the detection andresponse conditions of the technology-based variance. If this can be done, thetank system must be repaired prior to itsbeing returned to service. If such repairis major, a certification by anindependent, registered professionalengineer must be obtained andsubmitted to the Regional Administratorwithin seven days of returning the tanksystem back into service. Ifcontaminated soil cannot be removed ordecontaminated so that the tank system,upon return to service, will be equippedwith release detection capability at leastas effective as was in place prior to therelease and upon which the technology-based variance was granted, the owner/operator must close the system andprovide post-closure care in accordancewith § § 264.197 and 265.197, asappropriate. In this situation, if theowner/operator elects to replace orreinstall the existing hazardous wastetank system, he must provide secondarycontainment consistent with therequirements of § § 264.193 or 265.193and comply with the requirements of§§ 264.192 or 265.192, or reapply for avariance from the secondarycontainment requirement of today'sregulation.

If the release migrates beyond thezone of engineering control, the Agencywill consider the technology for whichthe technology-based variance wasgranted to have failed. In this case, theowner/operator must follow allprocedures in § § 264.196 and 265.196applicable to a release from a secondarycontainment system or a single-walledtank system to the environment.Furthermore, the owner or operator mustprevent the migration of hazardouswaste or hazardous waste constituentsto ground water or surface water, ifpossible. In addition, the owner oroperator must decontaminate or removethe contaminated soil. If he cannotdecontaminate or remove the

contaminated soil or if ground water hasbeen contaminated, he must close thesystem and provide post-closure care inaccordance with § § 264.197 and 265.197,as appropriate. In all cases, includingthose where contaminated soil can beremoved or decontaminated and groundwater has not been contaminated, if theowner/operator elects to repair, replace,or reinstall the existing hazardous wastetank system, he must provide secondarycontainment consistent with therequirements of § § 264.193 or 265.193and comply with the requirements of§ § 264.192 or 265.192, or reapply for avariance from the secondarycontainment requirements of today'sregulation.

(ii) Risk-based variance. The criteriathat the applicant must use whenpreparing requests for a risk-basedvariance from the secondarycontainment requirements of thisregulation are specified in§ § 264.193(g)(2) and 265.193(g)(2).Essentially, the applicant must be ableto demonstrate that as long as theconcentration(s) of the hazardousconstituent(s) present in the hazardouswaste stored, treated, or accumulated inthe hazardous waste tank systemremain(s) below the requestedconcentration limit(s), no substantialcurrent or potential hazard to humanhealth or the environment will result. Asexplained previously, this varianceprovision is not available to owner/operators of new undergroundhazardous waste tank systems.

This demonstration is essentially arisk assessment and risk managementprocess in which a determination ismade that, in the event of a release froma hazardous waste tank system, thelevel of contamination of ground waterthat results will not pose a substantialpresent or potential hazard to humanhealth or the environment. In makingthis demonstration, the owner/operatormust make a reasonable estimate of thelikely release incident that might occurfor his hazardous waste tank system.For example, a strong case could bemade that the likely release event froma completely aboveground hazardouswaste tank system would be acatastrophic release incident (i.e., theentire contents of the tank system wouldbe released). For underground,onground, and inground tank systems,the most likely event might be acontinuous release between the timeinterval of tank integrity assessments.Thus, the owner/operator would, basedon the precision and reliability of themethod used to conduct the periodictank system integrity assessmentsrequired by today's regulation, assume a

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constant release rate that would occurover the time interval between periodicassessments (generally one year). In theevent that a release rate cannot bereasonably estimated, the owner/operator would assume that the releaseincident would be a catastrophic releaseincident.

Site specific information, such as localhydrogeological characteristics, thefacility s waste constituents, and localenvironmental factors, is needed toassess the potential impact of eachhazardous waste constituent on humanhealth or the environment if it were tobe released to ground water or surfacewater. There are two approaches that anapplicant can take in thisdemonstration:

1. There will be no pathway toexposure to the hazardous wasteconstituents, or

2. The exposure to the ground-wateror surface water contaminants will be atconcentration levels that do not pose asubstantial current or potential hazardto human health and the environment.

In the second approach, thedemonstration depends upondetermining concentration levels of theground-water contaminants that do notpose a substantial current or potentialhazard to human health and theenvironment at a potential point ofexposure. The allowable hazardouswaste constituent concentration limitsare derived from these acceptableconcentrations.

Agency published acceptableexposure levels for the protection ofhuman health and the environment canbe used as allowable hazardous wasteconstituent concentration limits withoutgoing through elaborate exposurepathway analyses or fate and transportmodeling. For example, a health-basedacceptable ground-water exposureconcentration for a constituent thatmight migrate to the ground water canbe used as the allowable hazardouswaste constituent concentration limit.However, the allowable concentrationlimit may need to be modified to includean assessment of any cumulative effectsassociated with exposure to thehazardous waste constituent. Inaddition, exposure levels that theAgency established pursuant to astatutory authority that requires risk-benefit balancing or technology-basedstandards may not always beacceptable for purposes of this variance.It is anticipated that the Agency willperiodically publish and update a list ofacceptable dose levels that can be usedby permit applicants in preparing riskbased variance demonstrations. In thisregard, EPA intends to issue guidanceon the variance provisions prior to the

effective date of today's regulation andwill update this guidance as necessary.

The type and amount of informationneeded for a risk-based variancedemonstration depends on site-specificcharacteristics and which approach(either no exposure or no substantialrisk) is chosen. Both approaches requireinformation on the physical andchemical characteristics of the waste,flow direction and quantity of theground water, and hydrogeologicalcharacteristics of the site. Ademonstration based on the secondapproach requires additionalinformation. Depending on the basis forthe demonstration, one or more of thefollowing must be addressed in greaterdetail:

1. Current and future uses of groundwater and surface water (if applicable),

2. The proximity of the user of thewater~resources,

3. The existing ground-water andsurface water quality,

4. The potential human health risksand environmental damage fromexposure to the contaminants, and

5. The permanence of the potentialadverse effects resulting from exposureto the contaminants.

For any of the above factors that arenot submitted as part of the variancedemonstration, justification is requiredto explain why they do not need to beaddressed. Depending on the sitecharacteristics, either approach mayrequire information on the engineeredcharacteristics of the hazardous wastemanagement facility, the rainfallpatterns in the area, the existing qualityof ground-water and surface water (ifapplicable), soil type and characteristics(adsorptivity and permeability)determined by soil boring tests, and anycurrent or future institutional ground-water use restrictions. Thedemonstration for each hazardous wasteconstituent must be independent.

Sections 264.193(h) and 265.193(h)have been added to the final rule andspecify the schedules to be used inrequesting variances.

6. General Operatinq Requirements(§ 264.194 and § 265.194)

In the proposed rule, the generaloperating requirements of § 265.194included provisions for periodic leaktesting and a corrosion assessment. Inthe final rule, these requirements havebeen relocated to other sections in Part265 as part of EPA's reorganization ofthe rule. The only revision that has notbeen discussed is the modification to theproposed rule that requires 2 feet offreeboard for uncovered tanks. Thecomments pointed out that the 2 footfreeboard requirement did not take into

account tank volume, thus creating adisparity relative to tank capacity. Inorder to eliminate this result, EPA hasadopted the same language found in§ 264.194 which requires that uncoveredtanks have sufficient freeboard toprevent overtopping by wave or windaction or by precipitation.

7. Inspection (§ 264.195 and § 265.195)

The requirements of proposed§ 264.195 would have includeddevelopment and implementation of aschedule and procedure for inspection ofoverfill controls, daily inspection of theaboveground portion of tank systemsand data gathered from monitoringequipment, weekly inspection of theconstruction materials of, and the areaimmediately surrounding, the externallyaccessible portion of the tank system,and inspection of cathodic protectionsystems. The requirements forinspections in § 265.196 would havebeen identical except that dailyinspection of overfill controls wouldhave been required.

Several commenters stated that theproposed schedule of inspections ofcathodic protection systems was morestringent than other inspectionfrequencies specified for cathodicprotection systems by other Federalstandards and engineering societies(e.g., National Association of CorrosionEngineers (NACE)). After further studyof this issue, the final rule has beenmodified to include the NACE-recommended inspection standards.NACE RP-02--85 (Control of ExternalCorrosion on Metallic Buried, PartiallyBuried, or Submerged Liquid StorageSystems), which EPA has adopted forestablishing minimum inspectionrequirements, was prepared by a taskforce composed of corrosionconsultants, corrosion specialists for oiland gas transmission companies, gasdistribution firms, power companies,and communications companies;representatives of tank manufacturersand coating manufacturers/applicators;the National Bureau of Standards; theAmerican Water Works Association; theDepartment of Transportation; and othercorrosion experts.

The NACE document represents theconsensus of a wide range of corrosionexperts representing manufacturers,government, trade associations,consultants, and firms with experiencein corrosion protection of submerged orburied equipment constructed of metal.Since EPA has not undertakenindependent research, this consensusoffers the most reasoned approach tosetting the inspection standardscontained in today's final rule. Thus,

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consistent with the NACE findings,§ 264.195 and § 265.195, now requireinspection of a cathodic protectionsystem within six months of installationand annually thereafter to ensure that itis properly functioning. In addition, therule requires that all sources ofimpressed current be inspectedbimonthly (i.e., every other month).

A few commenters stated that therecordkeeping requirements in theproposed rule would create anunnecessary burden. The Agencystrongly disagrees with thesecommenters; EPA believes that it isimportant for owner/operators offacilities subject to this regulation tokeep a permanent record of theirinspections to document theircompliance with the rule. Thus, in anaddition to the proposed rule, the finalregulation at § 265.195 requires thatowner/operators of interim statusfacilities and accumulation tank systemsmaintain records of required inspectionsas was proposed for permittedhazardous waste tank systems in§ 264.195.

The other requirements of proposed§ 264.195 and § 265.195 remain the sameas proposed, except that inspection ofthe construction materials of and thearea surrounding the externallyaccessible portions of the tank andsecondary containment systems must beinspected daily. EPA has added thisrequirement because it will enable thedetection of releases or potentialreleases at the earliest possible time.Additionally, this inspectionrequirement can easily be incorporatedinto the daily inspection schedulerequired for the aboveground portions oftank systems (including all piping andother ancillary equipment). Pursuant to40 CFR 264.15 and 265.15, anydiscrepancies found during inspectionsmust be remedied.B. Response toLeaks or Spills andDisposition of Leaking or Unfit-for-UseTank Systems (§§ 264.196 and 265.196)

This section of the preamble describesprocedures the owner/operator mustfollow if his tank system has developeda leak or if he determines that a tanksystem'is unfit for use. Paragraph (a)describes what actions must be taken inresponse to a leak or spill from a tanksystem which has not been granted avariance from secondary containment.Paragraph (b) describes procedures fordisposing of tanks that have leaked orare unfit for use. Procedures forresponses to leaks or spills from tanksystems with variances are included in§ § 264.193 and 265.193 of the regulationsand are in section IV.B.5.d.i of thispreamble

a. General Responses to Leaks orSpills. Sections 264.196 and 265.196specify procedures the owner/operatorgenerally must follow if there is arelease (leak or spill) from a hazardouswaste tank system. For permitted tanksystems, the framework for respondingto releases is established, in part,through a contingency plan preparedunder Subpart D of Part 264. Section264.196 of today's regulation expandsthe requirements beyond those currentlyrequired by this plan and imposes otherrequirements. For interim status and 90-day accumulation tank systems,procedures for responding to leaks andspills are specified at § 265.196 oftoday's regulation.

The response procedures must befollowed ifa release is detected throughtank testing, visual inspection,interstitial monitoring, or in any othermanner.

There are three types of releases thatare addressed in § § 264.196 and 265.196:

(1) Releases from a single-walled tanksystem to the environment;

(2) Releases from secondarycontainment systems to the environment(if any); and

(3) Releases from primarycontainment devices (tank, piping, otherancillary equipment) into secondarycontainment systems.Generally, regardless of the type ofrelease, several response measures mustbe followed. For example, in all cases,the owner or operator must stop theinflow of hazardous waste to thatportion of the tank system that isreleasing the hazardous waste and mustremove hazardous waste from the tanksystem so that no further release willoccur. Other requirements of §§ 264.196and 265.196 vary with the type ofrelease as described below. A moredetailed discussion of each of theresponse procedures follows.

i. Stopping of Flow or Addition ofWastes. The final rule requires that if aleak or spill has occurred, the owner oroperator must immediately stop the flowor addition of hazardous waste into thetank system. This requirement applies toall types of releases: leaks or spills tothe environment or from the primarycontainment device to the secondarycontainment system. The purpose of thisrequirement is to limit, to the extentpossible the quantity of hazardouswaste that might potentially be releasedfrom the tank system. This requirementis identical to that contained in theproposal. No comments were receivedrelative to this provision.

ii. Removal of Waste from LeakingTank Systems. Today's rule requiresthat the owner or operator promptly

remove hazardous waste from thatportion of the primary tank system atwhich a leak or spill has or is occurring.It also requires that, in the event of arelease to a secondary containmentsystem, hazardous waste must beentirely removed from the secondarycontainment system. The proposed rulewould have required the immediateremoval of all waste from the tank andcontainment system when it was foundto be leaking. Many commentersobjected to that requirement. Theysuggested: (1) that immediate removal ofthe waste was only necessary above theleaking portion of the tank; (2) that, forleaks in the ancillary equipment orpiping, it is only necessary to isolate theleaking equipment or pipe section forrepair or replacement, and (3) that manyrepairs can be made without completeremoval of hazardous waste from thetank system.

EPA agrees with the commenters thatremoval of all waste from a single-walled leaking tank system may not benecessary under all circumstances. Amajor concern during a repair operationis the risk of potential exposure or directcontact of maintenance personnel withthe hazardous waste. Therefore, thefinal rule is revised to require measuresfor isolation of that portion of a single-walled tank system where a release hasoccurred or is occurring and promptremoval of remaining wastes from theleaking portion of the tank andcontainment system. The decision toremove all remaining waste should bebased upon consideration of health risksto repair personnel and the potentialrisk for further release to theenvironment.

For a tank system with secondarycontainment, all the leaked waste mustbe removed from the entire secondarycontainment system. If this were notdone, the interstitial monitoring systemwould not function effectively.

The proposed rule would haverequired removal of the hazardouswaste no later than 24 hours after a leakis detected. Several commenters arguedthat the 24-hour response time forremoval of waste was unreasonable andeven impossible for tanks withextensive interconnecting systems, largetanks, and facilities without adequatestorage capacity. The requirement in theproposed rule for removal of tankcontents within 24 hours has beenmodified in the final rule to requireremoval of the remaining waste tocommence within 24 hours of detectionof the leak and to be completed asquickly as possible so that no furtherreleases occur. In today's finalregulation, EPA has modified this

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requirement based on its considerationof the range of likely conditions thatmight be encountered in such situatiohs,Several major problem areas wereidentified in this analysis. The principalconcern was that any such transferoperation be accomplished in such amanner that human health not bethreatened. In the event of a leak, time isrequired to plan the transfer operationso that further spills or accidents areprevented. This cannot always beaccomplished within a 24-hour period.

Other logistics problems couldprevent removal within 24 hours. If therewere not sufficient tank capacityavailable that was compatible with thewastes being transferred, time would berequired to obtain such capacity. Thiswould be a special problem with large,interconnected tank systems. Finally, forextremely large tanks, more time may berequired to obtain alternative capacityand to transfer the waste physically.

Removal of wastes from a secondarycontainment system might encountersimilar difficulties. Accordingly, the 24-hour time limit has been modified forthese situations as well.

iii. Containment of Visible Releases tothe Environment. The final rule requiresthe owner or operator to contain anyvisible contamination resulting from arelease from the tank system to theenvironment. Only releases from anaboveground portion of a tank systemare likely to result in visiblecontamination. This requirement isunchanged from the proposal. Thepurpose of this provision is to requirethat measures be taken to minimize theimpact of a release by promptlycontaining it. An example of this type ofresponse would be the placement ofbarricades or other barriers to preventfurther lateral overland migration of theleak or spill.

In addition, the owner/operators mustconduct a visual inspection andpromptly remove, and dispose of, anysoil that appears to be contaminated.Likewise, if a release has reachedsurface water and is visible (e.g., an oil-sheen), the owner/operator must takeimmediate action to contain and removethe released material.These actions willresult in minimizing the "amount of soilor surface water that becomescontaminated and may also avoid morecostly future corrective actions.

iv. Notification of Release to theEnvironment. The final rule requires thatthe owner or operator notify theRegional Administrator within 24 hoursafter a release to the environment hasbeen detected. If the leak or spill isconfined by the secondary containmentsystem, notification is not required. Thepurpose of this notification is to provide

EPA the opportunity, in appropriatecases, to order that correction action betaken. Corrective action may berequired pursuant to sections 3008(h),3004(w), or 7003'of RCRA.

Many of the commenters stated thatthe proposed notification provisionsoverlapped with current CERCLArequirements. Under the ReportableQuantity rule (40 CFR, Part 302), arelease of a hazardous substance inquantities equal to or greater than itsassigned Reportable Quantity (RQ) mustbe reported immediately to the NationalResponse Center. To avoid duplicativenotification, the final rule clarifies thatan owner's or operator's reportcomplying with 40 CFR Part 302 willsatisfy the notification requirements ofthis regulation. Commenters on theproposed regulation stated that smallleaks and spills should not be reportedto the Regional Administrator becauseof their insignificance. EPA agrees thatto report small, insignificant spillsshould not be required. Accotdingly, thefinal regulation has been modified torequire that spills of less than or equalto one pound need not be reported ifthey can be immediately contained andcleaned up. This is equal to the lowest"reportable quantity" established in theCERCLA reporting regulations. EPA isconfident that owner/operators canperform the necessary cleanup ofreleases of this size without RegionalAdministrator involvement.

v. Assessment of Risk Posed by Leaksor Spills to the Environment. The owneror operatQr of a permitted, interimstatus, or 90-day accumulation tanksystem must, within 30 days of detectionof a release, submit a report to theRegional Administrator that estimatesthe extent of the release. The purpose ofthis requirement is to provide theRegional Administrator with sufficientdata (e.g., size of release, receptors,estimated corrective action, etc.) tomake a decision with respect to whattype and degree of corrective action, ifany, may be appropriate.

For permitted tank systems, the finalrule expands the requirements relatingto contingency plans prepared pursuantto Subpart D of Part 264. These plansmust now include procedures forassessing the risk to human health andthe environment caused by a releasefrom a tank system and the remedialactions necessary to mitigate therelease. Section 264.196 requires thatthese procedures be followed if therehas been a release to the environment.For interim status and 90-dayaccumulation tank systems, the finalrule expands upon the reportingrequirements of 40 CFR 265.56(j).

Pursuant to 40 CFR 265.56(j), owner/operators of interim status or 90-dayaccumulation tank systems mustprovide, in a report to the RegionalAdministrator by 15 days after theincident, certain details of any incidentthat requires implementing thecontingency plan. This report mustinclude:

(a) Name, address, and telephonenumber of the owner or operator;

(b) Name, address, and telephonenumber of the facility;

(c) Date, time, and type of incident(e.g., fire, explosion);

(d) Name and quantity of material(s)involved;

(e) The extent of injuries, if any;(f) An assessment of actual or

potential hazard to human health or theenvironment, where this is applicable;and

(g) Estimated quantity and dispositionof recovered material that resulted fromthe incident.

Today's rulemaking requires thatadditional items be included in a reportto the Regional Administrator within 30days of detection of a release. Theseadditional items to be addressed are:

(a) Likely route of migration by therelease;

(b) Characteristics of the surroundingenvironm6nt (soil composition, geology,hydrogeology, climate);

(c) Results of monitoring/sampling (ifavailable);

(d) Proximity to downgradientdrinking water, surface water, andpopulation areas; and

(e) Remedial actions taken or to betaken.

In response to comments, the Agencyhas made these requirements morespecific than they were in the proposal.

b. Disposition of Leaking or Unfit-for-Use Tank Systems- i. Tank SystemsWithout Secondary Containment. Whena tank system without secondarycontainment is found to be leaking orunfit for use, the owner/operator can-close the tank system. in accordancewith § § 264.197 or 265.197, or resume useof it if he complies.with the following:

(a) Provide secondary containment:Sections 264.196(b) and 265.196(b)require that if a leak has occurred in anycomponent of the tank system (i.e., tank,piping), that is underground, thatcqmponent of the tank system must beprovided with secondary containmentprior to being returned to service.Additionally, if a leak has occurred inany portion of a tank system componentthat is not readily accessible for visualinspection (e.g., the bottom of anonground tank), the entire componentmust be provided'with secondary

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containment before the tank system isreturned to service (egg,, in the eventthat a leak is found on the bottom of aninground tank, the entire tank must beprovided with secondary containmentprior to the tank system being returnedto service). If a leak is detected in anunderground piping system, the entireunderground piping system must beequipped with secondary containment.This requirement is consistent withEPA's strategy to require secondarycontainment for those hazardous wastetank systems presenting a substantialrisk of release of hazardous waste tosurface or ground water. EPA concludesthat it would not be prudent to allowthat portion of a tank system that hasexperienced a leak or failure in aninaccessible area to continue to operatewithout the added protection ofsecondary containment. This is becauseleaks in other inaccessible areas of thetank system may be imminent, and it isnot possible to anticipate and preventtheir occurrence. Any replacement tanksystem component is considered a newtank system component and must, in.addition to complying with thesecondary containment requirements oftoday's regulation, comply with therequirements for new tank systems(certification of design, properinstallation practices, etc.). If the tanksystem is replaced during interim status,a certification by an independent,qualified registered professionalengineer must be submitted to theRegional Administrator at least sevendays prior to bringing the replacementtank system into use, that attests thatthe tank system will be capable ofstoring or treating hazardous waste forthe intended life of the system under theanticipated operating condition withoutpermitting a release of hazardous wasteto the environment.

(b) Repair: In some circumstances, aleaking or unfit-for-use component of asingle-walled tank system may berepaired and returned to use withoutbeing equipped with secondarycontainment. If the portion of the leakingor unfit-for-use component isaboveground and can be inspectedvisually, repair without secondarycontainment is allowed. This includessuch items as flanges, pipe fittings,pumps, and valves that are part ofaboveground piping systems.

If major repairs have been performed,the owner/operator must submit acertification to the RegionalAdministrator seven days afterreturning the tank system to use. TheEPA proposed to require owners oroperators to submit a certification by aqualified registered professional

engineer that the system, when repaired,was capable of handling hazardouswastes without release for the intendedlife of the tank system. EPA proposedthat this certification be submitted to theRegional Administrator, whenever anyrepair was performed, at least sevendays prior to the return of the tanksystem to service. The purpose of thisrequirement was to give the RegionalAdministrator ample prior notice sothat, if desired, an inspection of therepaired tank system could beperformed, prior to its being put backinto service. Commenters asserted thatthis requirement was unreasonable. Apoint they raised was that tank systemsare often components of a continuously-operating system, and the requirementfor seven day notification wouldunnecessarily restrict or shut downoperations. Another reservation wasthat the requirement was unreasonablefor minor leaks, which are usuallyquickly repaired.

The Agency has reevaluated thisproposed requirement and hasdetermined that it is overly burdensomein some situations. EPA has modifiedthe final rule in § § 264.196(b) and265.196(b) to require that thecertification of major repairs besubmitted within seven days of the-tanksystem being returned to service. Thiscertification would be necessary, forexample: for repaired abovegroundportions of tanks; for extensive repairsthat have been performed subsequent toa rupture or other major loss ofstructural integrity (e.g, when there isloss of structural integrity as a result ofan accident such as puncture by aforklift, a catastrophic event such asfire, explosion, flood, or seismic event, aprocess malfunction such as overheatingor overpressurization, or other eventthat results from improper design orinstallation, such as seam-weld breaks,foundation failure, or extensivelocalized corrosion). Certification is notrequired for such day-to-day routinemaintenance or service practices asreplacement or repair of worn portionsof tank system components (e,g., valves,bearings, seals), adjustment or repairs toinstruments, etc.

ii. Tank Systems With SecondaryContainment. When a hazardous wastetank system with secondarycontainment is found to be leaking orunfit-for-use, the owner/operator canclose the tank system in accordancewith § § 264.197 or 265.197, or resume itsuse if he complies with the following:

(a) Repair: In the case of repairs to theprimary containment system, the sameprocedures described above for repair ofsingle-walled hazardous waste tank

systems would apply. For all repairs tothe secondary containment system, theowner/operator must submit acertification to the.RegionalAdministrator seven days afterreturning the tank system to use. Thiscertification would be necessary, forexample: for repairs of tears in liners,cracks in concrete vaults, or rupture ofthe outer wall of a double-walled tank.Additionally, the owner/operator mustcomply with the certificationrequirements of § § 264.196(f) and265.196(f).

(b) Replace: In the event that theowner/operator decides to replace,rather than repair, the primarycontainment system of a hazardouswaste tank system equipped withsecondary containment or to replace thesecondary containment system, theowner/operator must comply with§ § 264.192 and 264.193 or § § 265.192 and265.193, as appropriate.

9. Closure and Post-Closure Care(§§ 264.197 and 265.197)

Under the previous Subpart Iregulations, the closure requirements fortanks (§§ 264.197 and.265.197) werebrief:

At closure, all hazardous waste andhazardous waste residues must be removedfrom tanks, discharge control equipment, anddischarge confinement structures.

The proposed rules made severalchanges to these existing closurerequirements. Identical changes wereproposed for both permitted and interimstatus facilities under Parts 264 and 265.The changes generally parallel thecurrent closure regulations in § 264-258for permitted waste pile facilities. Theproposal extended the closurerequirement provisions to include soilsand the entire tank system, not just thetank. The proposal also required thattank systems meet the closure and post-closure requirements for landfills if notall contaminated soils could beremoved. Tank systems withoutsecondary containment (and thus mostlikely to have extensive soilcontamination and most likely -to needpost-closure car6) were required toprepare contingent closure and post-closure plans, to plan for the possibilityof closing as a landfill. Finally, theproposal made conforming changes tothe applicability sections of Subparts Gand H so that post-closure carerequirements would apply to certaintank systems.

Thefinal rules are being promulgatedsubstantially as proposed; however,clarifications were added explicitlylisfing the closure post-closure, and

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financial responsibility requirementswhich apply to tank systems whichintend to close as landfills or to tanksystems that must prepare contingentclosure and post-closure plans.

The final rule makes five majorchanges to the previous Subpart Jregulations. Each of these changes willbe discussed in more detail, along withthe rationale for each change and adiscussion of any comments received.

First, the closure requirements in§ 264.197(a) and § 265.197(a) have beenexpanded to include the entire tanksystem, not just the tank. This isconsistent with the new definition of"tank system" in § 260.10, and consistentwith the Agency's intent that allcontaminated hazardous wastemanagement apparatus be removed ordecontaminated at closure. Thus, atclosure, the owner or operator of a tanksystem is now required to remove ordecontaminate the tank, its ancillaryequipment, and its secondarycontainment system, if used.

Second, the closure requirements in§ 264.197(a) and § 265.197(a) have beenexpanded to include contaminated soils.These new requirements are consistentwith previous Agency intent, and withthe general closure performancestandard in Subpart G to "protecthuman health and the environment." Itis also consistent with the recentlypromulgated revisions to Subpart G, (51FR 16422; May 2, 1986), which requireexplicitly in § 264.114 and § 265.114 thedecontamination of soils. It should benoted that decontamination of saturatedsoils (i.e., ground water) would benecessary for a closure that would notrequire post-closure care.

Commenters expressed concern overthe requirement to decontaminate soil,and the extent and degree to which thesoil must be decontaminated EPA hasnoted these comments but stillconcludes that the closure and post-closure requirements are both properand reasonable. The final rule requiresthe removal or decontamination of allcontamination at closure of the tanksystem. If this is not practicable, theregulation provides for post-closure careof the unit. This regulation does notdefine the level of decontamination.EPA is currently developing policy onthe broad issue of defining acceptablelevels of contamination (i.e., how cleanis clean) outside the scope of thisrulemaking. The new tank regulationsare intended to prevent releases fromtank systems and to eliminatecontamination to the surrounding soil sothat neither human health nor theenvironment is endangered subsequentto closure of the system. Furthermore,the final rule includes a significant

change from the proposed rule byestablishing a secondary containmentrequirement for all new and existingtank systems. This should considerablyreduce the amount of contaminated soilgenerated during the lifetime of a tanksystem, thus substantially reducing theamount of soil requiringdecontamination and post-closure care.

The third major change was therequirement in § 264.197(b) and§ 265.197(b) that a tank system owner oroperator must meet the post-closurelandfill requirements of final cappingand ground-water monitoring set forth in§ 264.310 or § 265.310 in the event that itis not practicable to remove ordecontaminate all contaminated soils atclosure. This post-closure carerequirement was included because thereis the potential that a release from anytank system, especially one withoutsecondary containment, could be leftunmanaged after closure. The Agencybelieves that an impermeable cap overthe contaminated area will reduce thepossibility of the waste in the soilmigrating into the ground water. Inaddition, implementation of a ground-water monitoring program would ensurethat human health and the environmentare not adversely impacted during thepost-closure care period if thecontamination moves offsite.

The Agency does not expect norintend that many tank systems will beclosed as landfills. However, this optionis being provided to address thepossible cases where extensive soilcontamination has occurred. Also, theowner or operator cannot decideunilaterally to close his tank system as alandfill. New closure and post-closureplans would have to be prepared andsubmitted to the RegionalAdministrator. and these modified plansmust still comply with the generalclosure performance standard to protecthuman health and the environment.

The fourth major change in the rules(§ 264.197(c) and § 265.197(c)) requiresthe owner or operator of tank systemswithout secondary containment toprepare contingent closure and post-closure plans to ensure that they haveadequately planned for the possibility ofclosing the tank system as a landfill.These plans would be used only if allcontaminated residues and soils couldnot be practicably removed at closure.EPA believes that contingent closureand post-closure plans should berequired for facilities with tank systemswithout secondary containmentbecause, if such a tank system has hadundetected leaks or spills in the past, itis possible that the material cannot bepracticably removed from the soil andthat the tank system might have tobe

closed as a landfill. Implementation ofthe contingent closure and post-closureplans would ensure that future threats topublic health and the environment fromthese past releases at closed facilitiesare minimized, monitored, andcontrolled as necessary.

In this final rule, an owner or operatorof a tank system that receives avariance under § 264.193(g) or§ 265.193(g) from the secondarycontainment requirements need notprepare contingent closure and post-closure plans for the possibility ofclosing as a landfill. Although no publiccomments were received regarding thispoint, EPA believes that such planswould not be necessary for such a tanksystem because the Agency would havepreviously examined the tank system'sdesign, operation, and locationcharacteristics in determining thelikelihood of hazardous wasteconstituents migrating into ground wateror surface water during the post-closureperiod. Tank systems with secondarycontainment systems are not required toprepare contingent closure and post-closure plans, because these systemsare expected to prevent releases into theenvironment. However, under§ 264.197(b) or § 265.197(b), if it isdetermined that any tank system hasreleased hazardous waste which cannotbe removed or be decontaminated atclosure, then that tank system must alsomeet the post-closure requirements of§ 264.197(b) or § 265.197(b). Similarly, ifthere is evidence of leakage from a tanksystem before the installation ofsecondary containment, the leak wouldhave been addressed pursuant to§ 264.196 or § 265.196. (See section V.E ofthis preamble.)

In the final rule, additional languagewas added to clarify the Agency's intentthat the cost estimates andcorresponding financial responsibilitymust reflect the costs of complying withthe contingent closure and post-closureplans, if those costs are greater than thecosts of complying with the expectedclosure plan.

The fifth change from the previousSubpart J requirements makesconforming changes to the applicabilitysections of Subparts G and H,(§ § 264.110, 264.140, 265.110, and 265.140)to implement fully the changes to theclosure requirements for tank systems in§ 264.197 and § 265.197. Theseconforming changes make it explicit thata tank system which closes as a landfilland performs post-closure care as alandfill is subject to the general post-closure care and corresponding post-closure financial responsibilityrequirements for disposal units in

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§§ 264.116 through 264.120, and§ § 264.144 through 264.146 (and theparallel sections in Part 265). Previously,a tank system was subject only to thegeneral closure requirements and thecorresponding closure financialresponsibility requirements. Additionalminor changes were made in theapplicability sections in the finalregulations to make the regulationclearer and consistent with the recentlypromulgated revisions to Subparts Gand H, (51 FR 16422; May 2, 1986).

10. Special Requirements for Ignitable orReactive Wastes (§ 264.198 and§ 265.198)

The proposed requirements in§ 264.198 and § 265.198 were the same asthe existing special requirements forignitable or reactive wastes except thatthe applicability of these requirementswas expanded to the entire tank systemrather than just the tank. The Agencymade this proposed change because therisks posed by ignitable and reactivewastes would seemingly be the same forpiping as for the tank itself. Onecommenter stated that it isinappropriate to require a buffer zonebetween tanks storing ignitable wastesand public properties since loadingfacilities are not often located nearpublic ways. The proposed buffer zonerequirement was intended to be inaccordance with the National FireProtection Association's (NFPA's)"Flammable and Combustible LiquidsCode." EPA has evaluated the commentand agrees that the NFPA 30 Code reallyonly does address buffer zonerequirements for tanks storingflammable and combustible liquids. Noreference is made in the code regardingapplying a buffer zone to piping or otherancillary equipment. No buffer zone isestablished for piping and otherancillary equipment because thegreatest fire/explosion hazard is posedat the tank, where a large volume ofignitable material is present, rather thanat piping/ancillary equipment whererelatively little ignitable material ispresent. Furthermore, it would beextremely difficult to define a specificdistance (buffer zone) from public waysfor this equipment that commonlyconsists of a complicated and extensivenetwork of piping. Thus, today's finalrule modifies the proposal by deletingthe term "tank system" from§ 264.198(b). The other requirements in§ 264.198 of today's final rules remain asproposed.

11. Special Requirements forIncompatible Wastes (§ § 264.199 and265.199)

The proposed standards in § 264.199and § 265.199 were the same as the pre-existing standards with only one minorchange: the owner or operator would berequired to ensure that the requiredprecautions for tanks are takenthroughout the entire tank system (i.e.,tank and ancillary equipment). Nocomments were received on thisproposed change to the existingstandards applicable to incompatiblewastes, and the final standards areidentical to those proposed.

12. Waste Analysis and Trial Tests(§ 265.200)

This section of today's finalrulemaking remains unchanged fromthat of the existing rule. As explained inthe proposed rule (see 50 FR 26487; June26, 1985), EPA did not repropose thissection and as such stated that it wasnot requesting or accepting publiccomment on this section.

The one comment that was submittedregarding the requirements of thissection suggested that the wasteanalysis and storage trial test are notnecessary if the tank was first properlyflushed to remove the residue of thewaste from previous storage TheAgency cannot accept this suggestion,because merely flushing the tank doesnot assure the tank design and materialsof construction can accommodate thewaste under question.

As explained previously, the final ruledoes not require the owner/operators of90-day accumulation tank systems toconduct waste analyses and trial tests.Unlike off-site commercial hazardouswaste storage and treatment facilitieswhere a wide variety of hazardouswastes are managed, generatorsgenerally produce and would thus storeor treat wastes that are relativelyconsistent in terms of their physical/chemical properties. Thus, EPA does notbelieve that waste analysis and trialtests must be conducted by generatorsof hazardous waste because of theirfamiliarity with the wastes theygenerate.

13. Special Requirements for Generatorsof Between 100 and 1,000 kg/mo thatAccumulate Hazardous Waste in Tanks(§ 265.201)

Today's final regulation does notapply to new or existing accumulationtank systems owned or operated by 100-1000 kg/mo generators who store up to6000 kg of wastes in a tank system forless than 180 (or 270) days. As explainedpreviously, these tank systems must

meet the requirements previouslyimposed by Subpart J in Part 265. Theserequirements appear in today's rule at§ 265.201.

14. Specific Part B InformationRequirements for Tanks (§270.16)

In order to receive a RCRA permit forhazardous waste treatment, storage, ordisposal facilities, an owner or operatormust submit sufficient information inParts A and B of a two-part permitapplication to demonstrate that afacility's methods of compliance aretechnically appropriate in relation to thePart 264 standards. The proposed rulewould not change the requirements forthe contents of the Part A application,which are in § 270.13 The contents ofPart B of the application are specified in§§ 270.14 through 270.21. The proposedrule would revise the specific Part Binformation for tanks in § 270.16, butwould not change the generalinformation requirements in § 270.14.

A commenter suggested that EPAclarify the information required of anapplicant for the ground-watermonitoring alternative that wasproposed. Today's final rule does notallow the substitution of ground water'monitoring for secondary containment.Thus, no change has been made. Thus,this portion of the final rule isessentially unchanged from theproposal. The specific Part Binformation requirements that apply totanks are revised under § 270.16 bytailoring the requirements to thetechnical standards for tanks in Part 264,Subpart J, of the final rule.

V. Analysis of Other SignificantComments

Following publication of the EPAproposal on June 26,1985, (50 FR 26444-26504) to revise the existing hazardouswaste storage and treatment tankstandards, a total of 89 publiccomments, including 9 comments madeat three public hearings conducted inAugust, 1985, were received. In additionto these comments. EPA also receivedand considered the 15 commentsubmittals filed on the Notice ofAvailability of Data and Informationthat was published on March 17, 1986(51 FR 90720) regarding the hazardwaste tank risk analysis. The commentswere received from individuals,corporations, Federal and Stateagencies, industry, trade associations,consultants, and public interest groups.EPA has evaluated all the commentsreceived and has modified the rulewhere appropriate.

This section of the preambleaddresses significant commentsreceived by the Agency that relate to

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this final rulemaking that are notaddressed elsewhere in this preamble.EPA has carefully reviewed allcomments relating to the final hazardouswaste tank standards and hasresponded to these comments in adocument entitled "Response toComments on the Revised RCRAHazardous Waste Storage andTreatment Tank Standards," USEPA,June 1986. This document is available bycontacting the RCRA Hotline and canalso be found in the docket for today'srulemaking.

A. Corrective Action for AccumulationTank Systems

Comment: One commenter cited avariety of perceivad shortcomings in theproposed regulation regarding correctiveaction for 90-day accumulation tanksystems. The commenter noted thatalthough EPA proposed to subject 90-day accumulton tank systems to theproposed interim status tank closureperformance standards, there is nomechanism for a reg.latory authority toreview or approve the closure. Inaddition, the commenter pointed outthat the proposed rule would requireowner/operators of 90-dayaccumulation tank systems to installsecondary containment, but did notaddress the issue of corrective action forprior releases.

Response: The commenter has raisedsome important issues with respect tocorrective action measures foraccumulation tanks. This is part of abigger issue relating to the exclusion ofcertain accumulation tank systems fromthe necessity to seek a RCRA permit. AnAdvanced Notice of ProposedRulemaking (ANPRI published intoday's Federal Register explains thatEPA is considering modifying theexemption from permitting foraccumulation tank systems, whichwould make some or all of these tanksystems subject to the same correctiveaction and other requirements as interimstatus or permitted tank systems. Atpresent the Agency can requirecorrective action for accumulation tanksystems in certain instances. Section265.196 of today's final regulationrequires accumulation tank owner/operators to notify the RegionalAdministrator within 24 hours of anyrelease to the environment (or theNational Response Center immediatelyif the quantity of waste releasedexceeds the CERCLA reportablequantity]. Thus, a regulatory authoritywill be notified when a release to theenvironment occurs. The regulatoryauthority will then have the opportunityto monitor the progress of the correctiveaction measures taken, including any

cleanup of prior releases. Additionally,under the provisions of section 7003 ofthe HSWA of 1984, EPA has theauthority to bring suit against an owner/operator on behalf of the United Statesupon receipt of evidence that the past orpresent handling, storage, treatment,transportation, or disposal of any solidwaste or hazardous waste may presentan imminent and substantialendangerment to human health or theenvironment.

B. Acutely Hazardous Waste

1. Variance Provision

Comment: A commenter objected tothe provisions in the proposed rulewhich would prohibit the owner/operator of tanks that store dioxin-contaminated F-listed wastes fromapplying for a variance from thesecondary contaitment requirements,and installing a ground-watermonitoring system in lieu of secondarycontainment. The commenter stated thatthese wastes may pose no greaterenvironmental hazard than otherhazardous wastes and that the proposedprohibitions seem arbitrary andcapricious.

Response: On January 14,1985 (50 FR2003], final amendments to Part 264were promulgated, specifyingmanagement standards for the storageand treatment of F020, F021, F022, F023,F026, and F027 dioxin-containing listedwastes in aboveground, inground, andunderground tanks that were enterablefor inspection. The January 1985 rulerequired secondary containment andleak detection devices for permittedtanks containing these wastes. The rulealso required the development ofprocedures for responding to a leak orspill. The placement of these wastes inlandfills, surface impoundments, wastepiles, or land treatment units wasrestricted and destruction and removalefficiency standards for incineratingthese wastes were specified.

Today's final rule extends thesecondary containment requirement toall tank systems treating or storing thelisted dioxin-containing wastes becauseEPA can find no basis for differentiatingbetween permitted, interim status, oraccumulation tank systems storing ortreating these highly toxic wastes.

As explained in the preamble to theproposed hazardous tank regulations (50FR 26489; June 26, 1985), the proposedhazardous waste tank rules would notallow owner/operators of new orexisting tank systems storing or treatingdioxin-containing wastes the option ofusing the ground-water monitoringalternative or of seeking a no-migrationwaiver because (a) it is well

documented that these extremely toxicwastes present a substantial hazard tohuman health and the environment and(b) it is EPA's experience that thesewastes are particularly difficult andexpensive to clean up.

After reconsidering this issue, EPAconcludes that it is acceptable to allowowner/operators of hazardous wastetank systems the opportunity to petitionfor variances to the secondarycontainment requirements specified intoday's final rule.

As explained previously in today'spreamble, EPA has rejected the ground-water monitoring alternative as a basisfor the final regulations applicable to allhazardous waste tank systems,including tank systems storing ortreating dioxin-containing wastes.

In the process of reviewing this issue,EPA revaluated the possibility ofmandating immediate secondarycontainment for a wider universe ofhighly toxic wastes then those relativelyfew represented by listed HazardousWaste Nos. F020, F021, F022, F023, F026,and F027

The Agency believes that it may beappropriate to apply the requirement toother materials that have been definedas acutely hazardous wastes. Twoseparate lists of acutely hazardousmaterials are currently being reviewedby EPA. These are (1) those materialslisted as acutely hazardous wastes in§ 261.33(e) and (2) those materials beingdefined as acutely hazardous underTSCA (see Notice of Availability ofChemical Emergency PreparednessProgram Interim Guidance (50 FR 51451;December 17, 1985)). In the future, EPAmay propose to require immediatesecondary containment for acutelyhazardous wastes other than the listeddioxin-containing wastes. Oneimplementation problem that EPA hasidentified is the fact that both the TSCAand RCRA lists noted above areindividual chemical lists. Thus, oneissue that may need to be addressedprior to proposing an additionalrequirement for acutely hazardouswastes is the concentration or amount ofthese materials that must be present in ahazardous waste such that immediatesecondary containment should berequired.

2. Requirements for Dioxin-ContainingListed Hazardous Wastes

Comment. One commenter objected tomore stringent requirements for tanksystems containing dioxin-containinglisted wastes The commenter does notbelieve EPA has supported that anygreater risk exists for these wastes,

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especially if concentrations of TCDD areless than 10 ppm.

Response: In a prior rulemaking (50FR 2003; January 14, 1985), EPA justifiedthe need for more stringent requirementsfor management of the dioxin-containinglisted wastes based on threeconsiderations: (1) the demonstratedtoxicity of the waste; (2) the tendencytoward long storage before treatment ordisposal; and (3) the difficulty andexpense of spill cleanup. Thejustification is more fully discussed inthe proposed rule dated April 4, 1983 (48FR 14514). See also 51 FR 1730 to 1733(January 14, 1986) noting the extremetoxicity of TCDD and other types ofdioxins as well as their migratorypotential and resistence. The proposedscreening level for TCDDs was in fact 8to 10 orders of magnitude lower than the10 ppm level cited by the commenter.The preamble to the proposed rulediscussed the proven and suspectedcarcinogenic, teratogenic, fetotoxic, andembryotoxic characteristics of thedioxin-containing listed wastes, even atlow concentrations. For these samereasons, the Agency believes thatimmediate secondary containment isrequired to ensure protection of humanhealth and the environment, unless acase-by-case variance is justified on thebasis of site-specific factors.

C. Small Quantity Generators

Comment: In response to the August 1,1985 proposed regulations (50 FR 31278),several State agencies supportedapplying to hazardous waste tanksystems owned or operated bygenerators of between 100 snd 1,000 kgof hazardous waste per month that areused to store hazardous wastes inexcess of 180 days (270 days) or 6,000 kgthe full provisions of the proposedhazardous waste tank standardsincluding secondary containment.

Response: As explained previously inthis preamble, today's rule applies in itsentirety to generators of between 100and 1,000 kg of hazardous waste permonth who accumulate hazardouswastes in tanks for more than 180 (270)days or in excess of 6,000 kg. However,today's final rule does not apply toaccumulation tank systems used bygenerators of between 100 and 1,000 kgof hazardous waste per month who storehazardous wastes for less than 180 (270)days and less than 6,000 kg. In the nearfuture, the Agency will proposehazardous waste tank system standardsthat would apply to this class ofaccumulation tank system.

D. Hazardous Waste Tank RiskAnalysis

Commenters generally did not supportthe use of the hazardous waste tank riskanalysis in developing or implementingthe final hazardous waste tank systemregulations. They provided two principalreasons for their lack of support: (1) therisk analysis is not currently able toreflect site-specific conditions, and (2)the models are based more onassumptions than on data.

1. Site-Specific Conditions

Comment: The Hazardous WasteTank Risk Analysis Model is notcapable of assessing site-specificsituations. Some hazardous waste tankfacility conditions may be amenable toalternatives to secondary containment;therefore, the results of the hazardouswaste tank risk analysis should not beused to justify requiring secondarycontainment for all hazardous wastetanks.

Response: The Agency developed thehazardous waste tank risk analysismethodology in order to estimate therelative risk reduction that would beachieved under different regulatoryoptions, in order to represent nationalvariation in tank types, waste types, andhydrogeologic conditions, EPAdeveloped numerous model tanksystems, model waste streams, andmodel hydrogeologic settings. Thesemodel conditions represented the mostcommon conditions associated withhazardous waste tank systems.

The Agency realizes that actualexisting tank systems, waste streams,and hydrogeologic conditions may varyfrom those represented in the analysis.However, to try to model all possiblecombinations of tank technologies,waste streams, and hydrogeologies thatmay occur across the nation isunreasonable and unrealistic, given thediversity of conditions that exist.

In order to develop national site-specific hazardous waste tankregulations, the Agency would need to-undertake an extensive data collectionexercise that would involve identifyingthe location of hazardous waste tanksystems in specific hydrogeologies,waste stream characteristics, anddistances to potential exposure points.Such information is not currentlyavailable for the existing universe ofhazardous waste tank systems.

Because of this lack of data, theAgency focused the risk analysis onidentifying the range of potentialconditions that would most likely beencountered at tank systems and therange of risk estimates associated withthe national population of hazardous

waste tank systems. The results of therisk analysis (i.e., the frequencydistributions of risk estimates) arebased on currently availableinformation and reflect the range ofestimates that would be obtained fromdetailed site-specific analyses.Consequently, although the Agency didnot conduct a detailed analysis of actualtank systems, the Agency believes thatthe risk analysis reflects the range ofestimates that would likely be obtainedfrom such a detailed site-specificanalysis.

Therefore, despite the lack of sitespecific-data, the Agency believes thatthe analysis was consistent in itsassumptions and provides a reasonablemethod for comparing regulatoryalternatives for reducing the riskspresented by hazardous waste tanksystems The analysis, along withevidence gathered from case studies,indicates that contamination of groundwater from leaking hazardous wastetank systems poses risk to humanhealth, and suggests that secondarycontainment is currently the mosteffective method for reducing the riskassociated with different tank systemtechnology options, hazardous wastes,and hydrogeologic conditions.

Although the Agency is requiring theeventual implementation of secondarycontainment for most hazardous wastetank systems, the Agency doesrecognize that certain site conditionsmay be amenable to alternativeprotective measures. Accordingly, twovariances from secondary containmentare provided in the regulations. (Seesection 111.B.5.b.ii of this preamble.)These variance' provisions allow for theconsideration of site-specific factors,such as particular tank characteristics,waste streams managed, andhydrogeologic setting, but will alsoencourage technological advances in thearea of release detection methods.

In summary, the Agency agrees thatthe model, as currently structured, is notsuitable for developing site-specificnational standards, nor, at this time, forimplementing risk based variances.However, the Agency does believe thatthe risk analysis results support the finalregulatory strategy for hazardous wastetank systems.

2. Modeling Assumptions

Comment: A number of commentersquestioned many of the basic modelingassumptions that were used in the riskassessment They explained that, inmany cases, due to data limitations, theassumptions did not have a strongfoundation. Among the assumptionscriticized were the following:

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- The effectiveness of leak testingand ground-water monitoring isquestioned by many experts; thus, anyconclusions drawn from the riskanalysis on these methods are invalid;

* The model does not includecorrective action;

- The PACE data is not an acceptablesample on which to base tank failures;

- The assumption that fiberglasstanks have twice the probability ofrupture as steel tanks is incorrect;

Response: The purpose of providingthe methodology and results for publiccomment was to supplement the datathat the Agency used to develop the riskanalysis model and to improve modelingassumptions where possible. For themost part, commenters did not providedata from which the risk analysis modelcould be modified or that would allowEPA to verify or refute the model results.As a result, given the assumptions thatthe Agency has made, the results of theanalysis and the conclusions drawnfrom them as presented in the March17th Notice of Availability have notchanged and appear to be reasonable.

Some of the most significantcomments on the notice are addressedbelow. All comments received by theAgency on the March 17th, 1986 Noticeof Availability are addressed in thedocket report, "Hazardous Waste TanksRisk Analysis Public Comments andResponses."

(a) Leak Detection and MonitoringMethods. In order to conduct theHazardous Waste Tanks Risk Analysis,EPA modified the previously-developedUnderground Storage Tank (UST) failuremodel to represent hazardous wastetank systems. The Agency assumed thatthe same leak testing and monitoringtechnologies that are employed forpetroleum tank systems can be used forhazardous waste tank systems. TheAgency received comments concerningthe reliability of various leak testing andmonitoring technologies and the lack ofhistorical performance data. The Agencyagrees that it had a limited data basefrom which to model such tank testingand monitoring technologies. However,enough data for petroleum tank systemleak testing and monitoring wasavailable to model such technologies fora relative comparisorn of theeffectiveness of regulatory alternatives.

As a result of recent research by theOffice of Underground Storage Tanks(OUST), EPA has since modified theUST failure model such thatassumptions about the reliability ofvarious leak testing and monitoringmethods have been modified. The USTfailure model now assumes that leaktesting is effective in detecting 95percent of the releases that are greater

than 0.1 gallons per hour, whereas theHazardous Waste Tank (HWT) failuremodel assumes that leak testing iseffective in detecting 100 percent of thereleases that are greater than 0.1 gallonsper hour. The UST model also assumesthat vapor wells are effective indetecting 80 percent of the releases thatreach the concentration limit, while, forthe supplementary analysis, the HWTfailure model assumed that vapor wellsare 90 percent effective in detectingreleases that reach the concentrationlimit.

In addition, EPA's Motor Fuel StorageTank survey results indicate that leaktesting technologies do not currentlywork as well as the vendors claim, evenfor petroleum tanks. (See "UndergroundMotor Fuel Storage Tanks: A NationalSurvey," EPA 560/5-86-013, June 1986.)The Agency has no reason to expectsuch methods to perform better forhazardous waste tank systems, even ifwe were to assume the tank must becleaned and the test performed usingwater. Therefore, from the more currentmodeling effort and an EPA field studyof leak detection methods, it is clear thatEPA overestimated the performance ofthe various leak testing and monitoringalternatives in the Hazardous WasteTanks Risk Analysis.

(b) Corrective Action. In theHazardous Waste Tanks Risk Analysis,EPA did not include extensive correctiveaction for hazardous waste tanksystems that were discovered to beleaking. EPA assumed only that tanksystems that were determined to beleaking would be removed and replaced.EPA did not account for correctiveaction, such as contaminated soil'excavation and ground water pumpingand treatment. Many commenters wereconcerned that the assumption of nocorrective action biased the analysistoward strategies that prevented leaks(e.g., secondary containment) ratherthan strategies that allowed fordetection and clean-up (e.g., leak testing,ground water or unsaturated zonemonitoring, etc.)

The Agency did not model correctiveaction because there were too manyvariables and too little data from whichestimates could be made, given theschedule for promulgating this rule. EPAconducted the Hazardous Waste TanksRisk Analysis by adapting existingfailure and risk models to representhazardous waste tank systems. TheAgency is currently developing a modelto estimate the effectiveness ofcorrective action for land disposal units;however, this component was notavailable for the Hazardous WasteTanks Risk Analysis. The timeframeavailable for the Hazardous Waste

Tanks Risk Analysis was insufficient fordeveloping a corrective actioncomponent given the complexity of themany necessary assumptions.

EPA does not agree that excludingcorrective action from the risk analysisbiased the results to the extent that theyare inaccurate. Consideration ofcorrective action in the model-if it hadbeen possible-would have shown thatother technical options would haveincreased in cost and still would havebeen inferior in protection of humanhealth and the environment incomparison to secondary containmentbecause, as previously discussed, theAgency does not know of any leaktesting or monitoring methods which,when used with single-walled tanks, arereliable enough to assure early detectionand expeditious corrective action. Forthe reasons discussed elsewhere in thispreamble, EPA has determined thatsecondary containment with interstitialmonitoring is the most effective andreliable method for preventing releasesfrom contaminating ground water orsurface water and, therefore, reducingrisks posed by hazardous waste tanksystem releases. The results of the riskanalysis were only one of many reasonsfor theAgency's selection of secondarycontainment as the Agency's generalapproach to regulating hazardous wastetank systems.

(c) PACE Data. EPA used the.Petroleum Association for Conservationof the Canadian Environment (PACE)data in the model to estimate the timingand frequency of steel tank corrosion.The PACE data contain information on300 underground petroleum tanks andwere collected by PACE to develop amethodology for siting futureinstallations of underground storagetanks. Consequently, the survey focusedon identifying the effect of soilproperties on tank corrosion failures.Soil samples were then taken at siteswith leaking tanks. In addition, all tanksat a site were tested for leaks. Thesurvey identified the soil propertiesassociated with 108 leaking tanks and192 non-leaking tanks.

The Agency received commentsexpressing concern that the use of thesedata will overestimate the frequency oftank corrosion failures because the datamay be biased towards leaking tanks.EPA agrees that, because the PACE datado not represent a statistical sample ofthe overall tank population, the PACEdata should not be used to determinethe percentage of tanks expected to beleaking at any given point in time.However, EPA used these data toprovide a rough estimate of theprobability of a steel tank corroding

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given the soil type and length of time thetank was in that soil. The PACE data arethe only available data that examine theeffect of soil variations on tankcorrosion and include information onnon-leaking tanks located in the samesoil environments as leaking tanks.Thus, its use in the model wasappropriate.

(d) Fiberglass Tanks. The only areawhere the commenters supplied theAgency with new information was withrespect to the fiberglass reinforcedplastic (FRP) tank rupture rate. TheAgency assumed that FRP tanks havetwice the probability of rupture as steeltanks. This assumption was based on acomparison of the annual failureprobabilities that were derived for steeland FRP tank ruptures. The Agencyreceived conflicting comments on thisassumption. Some commentersconsidered the 2:1 ratio as severelyoverestimating FRP tank ruptures, whileothers considered the ratio a severeunderestimate of the FRP tank ruptureprobability. All commenters on thisissue indicated that FRP tank rupturesare more likely to occur in the first fiveyears after installation.

However, even with this newinformation, EPA cannot revise theHazardous Waste Tank failure modelwith respect to the FRP tank rupture'probability. The information providedby commenters on this issue iscomplicated by additional areas ofuncertainty. For example, EPA receiveddata indicating that the ratio of thereported number of failed FRP tanks tothe number of FRP tanks sold in a givenyear is 0.25:1. This information does notprovide EPA with appropriate data toestimate the probability of a FRP tankrupturing or the percent of FRP tanksthat rupture over time. Therefore, it isnot clear from such new informationthat EPA s modeling assumption for theFRP rupture probability is wrong.

In one respect, the HWT failure modelunderestimated FRP tank failures. Themodel assumed that tank ruptures arethe only structural form of failure forFRP tanks. Results from EPA s motorfuel tank survey indicate that FRP tanksalso have the potential to develop slowleaks as a result of faulty construction.Thus, while the Agency agrees that theFRP rupture probability assumed in themodel may not be completely accurate,in the absence of definitive data and forthe purpose for which the model wasused, the assumptions were reasonable.

E. Contingent Post-Closure Plans

Comment. One commenter stated thatEPA should require contingent post-closure plans for facilities that installsecondary containment after there is

evidence of leakage from the tanksystem. The commenter believes that itmay be as difficult for these facilities toremove all contaminated material atclosure as it would be for facilities thatdo not have secondary containment.

Response: EPA has addressed thisissue in its requirements for correctiveaction for prior releases in order toobtain a permit. The HSWA require thatprior releases at facilities seeking apermit to manage hazardous waste beidentified and that corrective action betaken during interim status and, ifappropriate, that the requirement forcorrective action be made a condition ofa permit. Prior leakage also can beaddressed, if appropriate, undarauthority granted under sections 3008(h),3004(u), and 7003 of RCRA. Asexplained previously in section II.H,EPA is separately considering thebroader issue of corrective action forcurrently non-permitted accumulationtanks systems at facilities not otherwiserequiring a permit.

F. Integrity Assessments

Comment: One commenter asked thatEPA alter the final regulation to requireall tank system owners or operators tosubmit periodic tank integrityassessments to an EPA or state officerather than promulgate the proposedrequirement that the assessments bekept on file at the facility. Thecommenter believes the proposedapproach would limit private citizenaccess to these materials.

Response: EPA believes that arequirement to submit assessmentswould be unduly burdensome on owner/operators of tank systems, stateagencies, and EPA. Under section 3007of RCRA, EPA maintains the right toinspect these assessments at any timeand can request and make available anyassessment of interest to the public thatis not entitled to confidential treatment.For this reason, the final rule requiresonly that periodic tank system integrityassessments be kept on file rather thansubmitted to the appropriate regulatoryauthority.

G. Leak Detection Standard

Comment: One commenter supporteda leak testing standard of 0.05 gallonsper hour based on his experience inusing a specific test at his facility. Thecommenter also pointed out that hisexperience shows that EPAunderestimated the cost of leak testingmethods.

Response: A review of all availableinformation on the reliability of tanksystem tightness tests indicatesproblems in routinely detecting leaks of0.05 gallons per hour using test methods

similar to that used by the commenter.Thus, EPA is conducting furtherresearch on tank system tightness testmethods, including a method similar tothe one used by the commenter.

After re-evaluating the costs ofperforming tank system tightness testson hazardous waste tank systems, EPAfound that the costs of these tests hadbeen underestimated at proposal;therefore, EPA has modified its estimateof these costs to reflect the experienceof this and other commenters.

H. Wastewater Piping and TreatmentTanks

Comment: One commenter requestedthat EPA exempt wastewater piping andreturn lines used at surfaceimpoundments. The commenter justifiedthis request based on his judgment thatthis piping typically contains less than0.1 percent hazardous constituents byvolume. The same commenter askedthat this regulation not be applied towastewater treatment tank systems thatcurrently are exempt from RCRAregulation because of the cost andsimilar relative percentages of wasteconstituent volumes.

Response: This regulation does notalter the permit status of wastewatertreatment tank systems. Therefore, thoseunits if now exempted from thehazardous waste managementstandards will not be required to complywith the hazardous waste tank systemmanagement standards established inthis regulation. Available data showthat piping systems can be a significantsource of releases of hazardous wastesto the envi~onment. For this reason,piping systems ancillary to hazardouswaste tank systems are regulated by thisfinal rule in those cases where anowner/operator can demonstrate thatcircumstances that exist at his facilityare such that his system does not pose asubstantial present or potential hazardto human health or the environment.EPA has provided a variance procedureto allow consideration of thatinformation. (See section HI.B.5.b.ii ofthis preamble.)

I. Risks of Double- Walled Pipes

Comment: Commenters asked thatEPA consider the possibility ofincreased risks associated with double-walled pipes. The commenters suggestedthat double-walled pipes typically aremanufactured in shorter lengths thansingle-walled pipes, requiring morefittings and flanges for similar lengthpipelines. The commenters pointed outthat these connections are the mostlikely points of leakage.

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Response: EPA acknowledges that anincrease in the number of pipeconnections may be necessary, but inmany cases the connections can be ofall welded design. Thus, the increasednumber of fittings would not necessarilypresent added risks. Additionally,interstitial monitoring of the double-walled piping system allows detectionof leaks of hazardous wastes from theprimary piping system before release tothe environment. Therefore, secondarycontainment of piping systems andinterstitial monitoring will reducesignificantly the risks associated withpiping.

. Closure and Post-ClosureRequirements

Comment: One commenter suggestedthat it is inappropriate for EPA torequire removal or decontamination ofcontaminated soils unless the Agencydefines a level of contamination that isacceptable.

Response: The final rule requires theremoval or decontamination of allcontamination at closure of the tanksystem, If this is not practicable, theregulation provides for post closure careof the unit. As explained in sectionIV.B.9 of this preamble, EPA is currentlydeveloping a policy on the broad issueof defining acceptable levels ofcontamination (i.e., how clean is clean)outside the scope of this rulemaking.

K. Incentive to Store in Drums

Comment: One commenter suggestedthat standards for 90-day accumulationtanks will lead to a switch toaccumulation in drums. The commentersees additional environmental risks as aresult of the switch.

Response: EPA has placed permittingrequirements on facilities storing wastesin containers in Subpart I of Part 264. Tothe extent that EPA determines thatthere is a significant shift to storage incontainers and an increase in risk as aresult, the Agency may consider furtherregulation of container storage.

Additionally, in a noticeaccompanying today's rulemaking, EPAis seeking public comment on theappropriateness of regulatingaccumulation facilities consistent withthe management of hazardous waste intank systems and containers atpermitted facilities.

L. SPCC Regulations

Comment: One commenter suggeststhat existing Spill Prevention andControl Countermeasures (SPCC)regulations under the Clean Water Actprovide sufficient protection from tankleakage.

Response: SPCC guidelines aredesigned to protect surface waters.Therefore, EPA believes that additionalmeasures may be necessary to protectground Water. In the cases wherefacilities have provided adequatesecondary containment that protectsground water, this secondarycontainment system may be appropriatefor complying with this regulation.

M 24-Hour Detection Requirement

Comment: One commenter suggestedthat immediate sensing of leaks shouldbe required rather than the proposedrequirement that the detection device beable to detect leaks within a 24-hourperiod.

Response: While it is certainlydesirable to detect leaks as early aspossible, it may not always benecessary to achieve "immediatesensing" of leaks to protect humanhealth and the environment. It is thegoal of today's final rule to ensure thathazardous waste tank systems aremanaged in a manner that prevents themigration of hazardous waste beyond azone of engineering control (i.e., an areaunder the control of the owner/operatorthat, upon detection of a release, can bereadily cleaned up prior to the release-ofhazardous constituents to ground wateror surface waters) so that protection isafforded to human health and theenvironment. Furthermore, in manycases, site specific conditions (e.g.,backfill characteristics, leak size, wastetype) may not allow the immediatedetection of a release. Thus, the Agencydoes not require immediate sensing ofreleases in this final regulation.

N. Future Designated HazardousWastes

Comment: Several commenters statedthat the proposed rule had not takeninto account those tank systems that arebrought into RCRA at some future timedue to additional solid wastes beingdesignated as hazardous wastes.

Response: The Agency believes thatthe regulatiofi should take intoconsideration the applicability of therequirements to such hazardous wastetank systems. As a result, four sectionsof today's regulations (i.e., § § 264.192,264.193, 265.192, 265.193) contain specificprovisions for tank systems managingfuture designated hazardous wastes. Ineach of these sections, wherecompliance with a requirement must bemade within a defined time intervalbeyond a certain date, the Agency hasincluded a provision that allows thesame time interval for compliance forowners and operators of tank systemsmanaging any future-designatedhazardous wastes as is allowed in

today's regulation for tank systemscurrently managing hazardous wastes.

VI. Relationship to Current RCRAHazardous Waste Programs

A. State Authority

1. Applicability of Rules in AuthorizedStates

Under section 3006 of RCRA, EPAmay authorize'qualified States toadminister and enforce the RCRAprogram within the State. (See 40 CFRPart 271 for the standards andrequirements for authorization.)Following authorization, EPA retainsenforcement authority under sections3008, 3013, and 7003 of RCRA, althoughauthorized States have primaryenforcement responsibility.

Prior to the Hazardous and SolidWaste Amendments of 1984 (HSWA), aState with final authorizationadministered its hazardous wasteprogram entirely in lieu of EPAadministering the Federal program inthat State. The Federal requirements nolonger applied in the authorized State,and EPA could not issue permits for anyfacilities in the State which the Statewas authorized to permit. When new,more stringent Federal requirementswere promulgated or enacted, the Statewas obliged to enact equivalentauthority within specified time frames.New Federal requirements did not takeeffect in an authorized State until theState adopted the requirements as-Statelaw.

In contrast, under section 3006(g) ofRCRA, 42 U.S.C. 6926(g), newrequirements and prohibitions imposedby the HSWA take effect in authorizedStates at the same time that they takeeffect in nonauthorized States. EPA isdirected to carry out those requirementsand prohibitions in authorized States,including the issuance of permits orthose portions of permits affected by therequirements and prohibitionsestablished by the HSWA, until theState is granted authorization to do so.While States must still adopt HSWA-related provisions as State law to retainfinal authorization, the HSWA appliedin authorized States in the interim.

2. Effect on State Authorization

Certain portions of today's rule arepromulgated pursuant to pre-HSWAauthority, while other portions oftoday's rule are promulgated pursuant toprovisions added by HSWA. Section3001(d) of the HSWA mandatespromulgation of standards applicable tosmall quantity generators; section3004(o)(4) of the HSWA mandatespromulgation of standards requiring

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utilization of approved leak detectionsystems for new underground tanks; andsection 3004(w) of the HSWA mandatespromulgation of final permittingstandards for underground tanks thatcannot be entered for inspection.Therefore, sections of this regulationpromulgated pursuant to HSWAauthorities are the following: (a) interimstatus and permitting requirementsapplicable to tank systems owned andoperated by small quantity generators(section 3001(d)); (b) leak detectionrequirements for all new undergroundtank systems (section 3004(o)(4)); and (c)permitting standards for undergroundtanks that cannot be entered forinspection (section 3004(w)).

The following specifically identifieswhich sections of today's rules arepromulgated pursuant to HSWA forthose categories outlined above.

(ftl 3001(d) Requirements

Parts 264 and 265 requirements applicableto tank systems owned or operated by smallquantity generators are promulgated asI ISWA authorities.

(b) 3004(o)(4) Requirements

Secondary containment with interstitialmonitoring provides new underground tankswith leak detection systems capable ofdetecting leaks to the environment at theearliest practicable time. Measures which arenecessary to ensure that the secondarycontainment system is maintained and,therefore, that the leak detection system willwork properly are included as HSWAauthorities. The following sections of theregulations are HSWA authorities when theyare applied to new underground tanks:

260.10262.34[a)(i)-iricorporates all HSWA

authorities under § 265, Subpart 1, whichare promulgated pursuant to 3004(o)(41and are listed under this paragraph (b)

264.190264.192 (a)[l)(i), (a)(3), (a)(4), (a)(5), and

(b}-(g)264.193 (a)-(f, (g)(1), and (hi264.195265.190265.192 (a)(1)(i), (a)(3), (a)(4), (a)(5), and

(b)-(g)265.193(a)-(f), (g)(1), and (h)265.195

.270.14(b)270.16270.72(e)

(c) 3004(w} RequirementsThe following sections of the regulations

are HSWA authorities when they are appliedas permitting standards for undergroundtanks that cannot be entered for inspection:

260.10264.110264.1402645.190-264.199270.14(b)270.16

The regulation listed underparagraphs (a), (b), and (c) above arepromulgated pursuant to HSWA andwill be effective in both authorized andunauthorized States. Tanks in thesecategories must comply with the Federalregulations promulgated.today and withapplicable State requirements.Underground tanks that cannot beentered for inspection will be requiredto obtain a RCRA permit from EPA, aswell as any applicable State permits.New underground tanks will be requiredto obtain permits from both EPA and aState or a joint RCRA permit issued byboth EPA and a State.

All sections of these regulations whenapplied to inground tank systems,aboveground tank systems, ongroundtank systems, and underground tanksystems that can be entered forinspection are RCRA authorities.Requirements for new underground tanksystems that are not section 3004(o)(4)requirements (see above) are RCRArequirements. Tank systems in thesecategories, which are located inunauthorized States, must meet allFederal requirements. Tanks in thesecategories in authorized States are notrequired to comply with today's ruleuntil such time as the authorized Stateamends its rules in accordance with 40CFR 271.(e)(2). However, theserequirements are effective inunauthorized states by January 12. 1987.

a. HSWA Provisions. Those portionsof today's rule which are beingpromulgated pursuant to sections3001(d), 3004(o)(4) and 3004(w) ofHSWA, are being added to Table 1 in§ 271.1(j) which identifies the Federalprogram requirements implementingHSWA. These provisions take effectimmediately in all states, regardless oftheir authorization status. States mayapply for either interim or finalauthorization for the -ISWA provisionsidentified in Table 1.

EPA will implement the HSWAportions of today's rule in authorizedStates until they modify their programsto adopt these rules and themodification is approved by EPA. Forthese portions of the rule, a Statesubmitting a program modification mayapply to receive either interim or finalauthorization under section 3006(g)(2) or3006(b), respectively, on the basis ofrequirements that are substantiallyequivalent or equivalent to EPA's. Theprocedures and schedule for Stateprogram modifications are described in40 CFR Part 271.21 and discussed below.

b. Non-HS4,A Provisions. Thoseportions of today's rule which are notbeing promulgated pursuant to theHSWA will be applicable upon theFederal effective date only in those

States that do not have authorization.EPA will implement these requirementsin unauthorized states. States will not beable to obtain interim authorization forthe non-HSWA requirements becausethe statutory deadline has expired. Inauthorized States, the requirements willnot be applicable until the State revisesits program to adopt equivalentrequirements under State law. Theprocedures and schedules for Stateprogram modifications are described in40 CFR 271.21 and discussed below.

c. Program Modification Deadlines.Currently, § 271.21(e)(2) requires thatStates with final authorization mustmodify their programs within a year ofpromulgation of EPA's regulations ifonly regulatory changes are necessary.or within two years of promulgation ifstatutory changes are necessary. OnJanuary 6, 1986, the Agency proposed tomodify the § 271.21 deadlines for Stateprogram modifications (see 50 FR 489-504). Under the proposal, States wouldhave a longer time to modify theirprograms to implement non-HSWArules. The program modificationdeadline varied depending upon thedate of promulgation of the non-HSWArule. Also, the proposal included a one-time special deadline for the HSWAprovisions that occur before June 30,1987. Since this regulation contains bothHSWA and non-HSWA provisions,under the proposal, modificationdeadlines would vary depending onwhether the requirements in today's ruleare HSWA-related. The Agency expectsto publish this authorization rule in finalform by late summer. Whenpromulgated, this rule will establish newdeadlines for States to modify theirprograms for today's tank system rule.

States with authorized RCRAprograms may already haverequirements similar to those in today'srule. These State regulations have notbeen assessed against the Federalregulation being promulgated today todetermine whether they meet the testsfor authorization. Thus, a State is notauthorized to implement theserequirements in lieu of EPA until theState program modification is approved.Of course, States with existingstandards may continue to administerand enforce their standards as a matterof State law. In implementing theFederal program, EPA will work withStates under cooperative agreements tominimize duplication of effort. In somecases, EPA may be able to defer to theStates in their efforts to implement theirprograms, rather than take separateactions under Federal authority. In thoseStates authorized for portions of thetank permitting program, EPA will

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coordinate permitting efforts with theState pursuant to the Memorandum ofAgreement or other EPA/State jointpermitting agreement.. ,-. .

States that submit official.applicationsfor final authorization less than 12months after promulgation of EPA'sregulations may be approved withoutincluding standards equivalent to thosepromulgated. However.once authorized,a State must modify its program toinclude standards substantiallyequivalent or equivalent to EPA's withinthe time periods discussed above.B. Regulation of Underground ProductStorage Tanks (The UST Program)

There were a number of commentstouching on two issues related to theUST program. One group of commentersquestioned the validity of using datafrom studies on petroleum storagesystems as a basis for the proposed rule.EPA addressed this comment earlier inthe preamble. Another group ofcommenters were concerned thattoday's final rules would become aprecedent for the UST rules when theyare promulgated.

In the preamble to the proposed rule,EPA cautioned against concluding thatthe proposed rules of June 26, 1985,would establish precedents for theAgency's effort to regulate, underSubtitle I of RCRA, underground storagetanks containing "regulatedsubstances." EPA explained that, in fact,"the requirements proposed today, asthey apply to underground hazardousstorage tanks, mqy be significantlydifferent in many ways from thestandards that will be developed in thefuture for underground tanks storingregulated substances," (See 50 FR 26490;June 26, 1985.) Regulations governingunderground storage tanks are beingdeveloped separately from thehazardous waste tank regulations.

Differences in statutory language, thenumber of tanks to be regulated, theregulatory scheme, and developinginformation about technical options andtheir reliability may cause regulationsfor underground storage tanks to differfrom those for hazardous waste tanksystems. For example, whereas thedevelopment of regulations for SubtitleC tank systems is based solely on thecriterion of protection of human healthand the environment, Subtitle I indicatesthat EPA may distinguish betweendifferent types of tanks and mayconsider other factors such as currentindustry practices, national consensuscodes, and small businessconsiderations. The undergroundstorage tank regulations will apply toover 1,000,000 tank systems, a vastlygreater universe than the hazardous

waste tank systems universe. Inaddition, Subtitle I does not requireimplementation of a permit system, adifference which may lead to a differentregulatory approach. Currently, theAgency is actively studying methods ofdetecting leaks from tank systems.Results from these studies may indicatethat leak detection methods whosereliability is unestablished today (e.g.,soil gas monitoring in the unsaturated orexcavation zone) may be found to bereliable before the underground storagetank regulations are issued. Finally, theAgency may take a different approachto regulating product storage if EPA

- determines that particular products,because of their value, are managedmore reliably than hazardous wastes.

C. Relationship of Regulation to Section3014(c) of RCRA

The Congress, in passing the Used OilRecycling Act of 1980 (Pub. L. 96-463),and the Hazardous and Solid WasteAmendments of 1984, supplemented thebasic requirements for regulation ofhazardous waste with certain specialrequirements for recycled oil. Theserequirements are found in section 3014of the Act. Section 3014(a) retains thelanguage of section 7(b) of the Used OilRecycling Act:

* * ' The Administrator shall promulgateregulations .. .as may be necessary toprotect the public health and the environmentfrom hazards associated with recycled oil. Indeveloping such regulations, theAdministrator shall conduct an analysis ofthe economic impact of the regulations on theoil recycling industry. The Administratorshall ensure that such regulations do notdiscourage the recovery or recycling of usedoil.

Section 242 of the 1984 Amendmentsalso added the following phrase to theabove paragraph, "consistent with theprotection of human health and theenvironment" to make it clear thatprotection is of prime concern under,section 3014, and that certain recyclingpractices may indeed be discouraged byregu!ation if necessary to ensure anadequate level of protection. (See H.R.Conf. Rep. No. 1133, 98th Cong. 2d Sess.114 (1984)).

Section 3014(b) requires theAdministrator to propose whether to listor identify used crankcase oil and otherused oil as a hazardous waste undersection 3001 of RCRA. EPA hasproposed to list all used oil as ahazardous waste (50 FR 49258-49270;November 29, 1985) and has alsoproposed management standards forused oil generators, transporters, andrecycling facilities (50 FR 49250-49258;November 29, 1985). .

• In listing used oil as a hazardous..waste, and in devising managementstandards associated with the recyclingof hazardous waste, EPA has attemptedto take into account the effects suchlisting -and standards will have on theultimate disposition of used oil. The ,objective of the proposed regulationswas to establish standards for therecycling of used oil that are mostprotective of the environment while notcreating significant disincentives orbarriers to the practice.

In keeping with the stated objective ofsection 3014 of RCRA in notdiscouraging recycling, while ensuringprotection of human health and theenvironment, EPA proposed a special,reduced set of storage standards for.recycled oil generators to minimizeadverse small business and recyclingimpacts. EPA also proposed differentand less stringent standards for smallquantity recycled oil generators whomay generate up to 1,000 kg/month ofused oil, and do not accumulate used oilin quantities exceeding 1,000 kg. (This isnot to be confused with Small QuantityGenerators.who generate greater than100 but less than 1,000 kg/month ofhazardous wastes; a large quantitygenerator of hazardous waste can stillqualify as a small quantity recycled oilgenerator.) In the preamble to theproposed used oil managementstandards, EPA explained that suchreduced standards for small quantityrecycled oil generators would offer thefollowing benefits: (1) reduce economicimpacts on small businesses; (2)facilitate recycling; and (3) encouragesmall quantity recycled oil generators torecycle used oil rather than dispose it ina manner that may threaten human

'health and the environment.Although the proposed regulation

would generally reduce standards forstorage of recycled oil, if promulgated asproposed, it would require that fullsecondary containment apply to tanksystems at non-generating facilitiesstoring such used oil. At this time,however, the rules are still in proposedform and EPA is in the process ofevaluating comments submitted duringthe public notice period. The commentsreceived were extensive, and havecaused EPA to consider alternatives tothe proposed regulation. In particular,EPA issued anextension to the publiccomment period in the March 10, 1986Federal Register (51 FR 8206). In thatnotice, EPA solicited additionalcomment on a regulatory approachsuggested by several commenters: listused oil as a hazardous waste only if itis disposed rather than recycled. EPA isin the process of evaluating the

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Federal Register / Vol. 51, No. 134 / Monday, July 14. 1986 / Rules and Regulations

additional comments received from thisnotice. EPA is particularly concernedabout the impact on used oil recyclingthat would occur as a result of theproposed management standards andthe proposed listing of used oil as ahazardous waste. EPA is also concernedabout the impact of a used oil listing oninsurance costs, as it would affect usedoil recycling, as well as the effect of theproposed management standards andlisting on the overall risks to humanhealth and the environment posed byused oil recycling and/or disposalpractices.

Today's rule does not address storageor treatment of used oil; rather, used oilmanagement standards will be includedin the used oil regulations scheduled tobe issued in November 1986. Thatregulatory package will fully address allapplicable tank standards for thestorage of recycled used oil.

Today's regulatory package willestablish standards, however, for usedoil that is mixed with listed hazardouswaste or that is mixed withcharacteristic hazardous waste andcontinues to exhibit a characteristic.This is because used oil, whether it isrecycled or not, that is mixed with anysuch hazardous wastes continues to beregulated as a hazardous waste underthe "mixture rule" (40 CFR 261.3(a)(2)(iii) and (iv)).

VII. Economic Analysis

The Agency undertook an analysis ofthe final hazardous waste tankregulatory amendments to determine theextent of associated cost and economicimpacts on the regulated community.The regulated community that weanalyzed includes existing or newinterim status, permitted, andaccumulation tanks, except new orexisting small quantity generator (SQG)accumulation tanks. These analyses alsoprovided the Agency with the necessaryinformation for determining whether therevisions will constitute a major ruleunder Executive Order 12291 or havesignificant impacts on a substantialnumber of small businesses, which theAgency is required to consider under theRegulatory Flexibility Act.

The following discussion summarizesthe methodology and results of theanalyses supporting these findings.Further details on the cost and economicanalyses for the final tank regulationscan be found in the docket reports, CostAnalysis of RCRA Regulations forHazardous Waste Tank Facilities andEconomic Impact Analysis of RCRARegulations for Hazardous Waste TankFacilities.

A. Cost and Economic ImpactMethodology

The analysis in these reports is basedon the cost estimates for facilitiessampled in the Office of Solid WasteRegulatory Impact Analysis (OSW RIA)and Small Quantity Generator (OSWSQG) surveys. The data from the RIATank and Generator survey indicatethat the final tank regulations couldaffect facilities in a variety of two digitSIC's. The most prominent SIC's arechemicals and allied products;petroleum and coal products; fabricatedmetals; and electronic and electricequipment. For small quantity generatortank facilities, the most prominent twodigit SIC's include Printing andPublishing, Primary Metal Industries,Automotive Dealers and ServiceStations, and Auto Repair, Services, andGarages.

EPA estimated incrementalcompliance costs for Parts 262, 264, and265 for each sample facility in the RIAsurveys. The focus of the final rule forexisting hazardous waste tank systemsis the requirement for secondarycontainment. EPA projected thesefacility costs by summing theincremental compliance costs for alltanks at each facility in the data base.We estimated the incrementalcompliance costs from cost functionsdeveloped for tanks based on materialof construction, size of the tank, andtype of tank.

For existing regulated tanks, EPAestimated the cost of retrofitting fullsecondary containment at the time ofthe appropriate phase-in age(§ 265.193(a)) for each tank in the surveysample. During the interim period priorto phase-in of full secondarycontainment, we applied the annual costof a periodic tank integrity assessment.For example, if an underground tankwas reported to be 10 years old, weapplied the cost of an annual integrityassessment for 5 years prior toretrofitting with full secondarycontainment at age 15. In addition, weestimated the cost of providingcorrosion protection for all replacementsteel tanks in contact with the soil.Depending on the tank system, othercompliance cost estimates includedrecordkeeping and reporting of integrityassessments, contingency plans. andpost-closure plans.

The generator and SQG surveys donot provide tank age data. Because thisis a crucial factor in estimatingcompliance costs, the Agency assumedthat the tank age distribution for storagetanks reported in the RIA Tank surveydata, are representative of theaccumulation tanks in the generator

surveys. This age distribution varies bytype of tank (above, in, or underground).Thus, a median age of 6 years for acradled storage tank is the median ageEPA assumed for cradled accumulationtanks.

According to the SQG survey data,the Agency does not expect many SQGtank facilities to require compliancewith the full interim status or permittingrequirements of this final rule. TheAgency has come to this conclusionbased on the data from the SQG surveywhich indicate that most SQG tanksstore waste for less than 180 days. Inaddition, the Agency believes that SQGtank facilities that currently store forlonger than 180 (270) days and,therefore, would be subject to theinterim status and permittingrequirements in this final rule, mayreduce their storage periods to less than180 (270) days to avoid expensivepermitting requirements such as theclosure, contingent closure, andcontingent post-closure plans.

Because the Agency expects so fewSQG tank facilities to be subject to theinterim status and permittingrequirements in this final rule, we havenot estimated a national cost for theregulated SQG tank population. Instead,Table 4 provides typical compliancecosts for three SQG tank facility types.

Tables 5 and 6 display theincremental costs new tank facilitieswill face under the final tank permittingstandards. The two smallest tanks ineach of the tables are representative ofthe types of tanks that small quantitygenerators are likely to install. Thesecosts represent installing new tanks thatcomply with the full secondarycontainment requirement. In.addition,new steel double-walled tanks incontact with the soil must havecorrosion protection.

TABLE 4.-ESTIMATED COMPLIANCE COSTS

FOR TYPICAL SOG TANK FACILITIES SUBJECTTO INTERIM STATUS AND PERMITTING TANK

REQUIREMENTS

Compliance cost estimates

Facility type Initial AnnualizedO&M

Pre.tax After-tax

Two $10,058 $1,600 (yr $2,501 $2,173under- 1-7), 640ground (yr 8-20).tanks.

Two 4,795 966 (yr 1-8), 1,661 1,434above. 1,200 (yrground 9-20).tanks.

One 8,112 2,083 (yr 1- 2,646 2,288above 7), 803 (yrground 8). 920 (yrand one 9-20).under-ground.

Source: Cost Analysis for Hazardous Waste Tank Rule;June 1988.

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TABLE 5.-INSTALLED BEFORE-TAX COSTS FOR NEW CARBON STEEL UNDERGROUND TANKS WITH FULL SECONDARY CONTAINMENT ($1,000)

Size of Cost of tank systems w/o secondary Cost o1 tank system wlsecondary Incremental cost of secondary

Nibe of containment containment containmentNumber of tanks tanks(gallons) Initial O&M Annualized Initial O&M annualized Initial O&M Annualized

I 285 $1.66 0 $0.24 $07.31 $0.25 $1.28 $5.65 $.25 $1.051 ............................................................................... 550 2.17 0 0.31 9.14 .25 1.54 6.97 .25 1.24

S............................. ................................................ 3,000 10.00 0 1.40 23.00 .25 3,50 13.00 .25 2:10

1 ................................... ................................... 10,000 19.00 0 2.70 39.00 .25 5.80 20.00 .25 3.10

.................... 20,000 30.00 0 4.20 57.00 .25 8,10 27.00 .25 4.10

3.................................................. 10,000 48.00 0 6.80 103.00 .25 14.80 55.00 .25 8.00

Source: Cost Analysis for Hazardous Waste Tank Rule; June 1986.NOTE.-Full secondary containment costs included a double-walled tank, double-walled piping, and a leak detection system. The 285 and 550 gallon tanks have 15 feet of piping per tank,

the remaining tanks have 50 feet o1 piping per tank.

TABLE 6.-INSTALLED BEFORE-TAX COSTS FOR NEW CARBON STEEL ABOVEGROUND TANKS WITH FULL SECONDARY CONTAINMENT ($1,000)

Size of Cost of tank systems w/o secondary Cost of tank system w/secondary Incremental cost of secondary

Number of Tanks tanks containment containment containment

(gallons) Initial O&M Annualized Initial O&M Annualized Initial O&M Annualized

275 $0.69 $0 $0.10 $01.26 $0.25 $0.43 $0.57 $0.25 $0.335 1.............................................................................. 550 1.48 0 0.21 2.16 .25 0.56 0.67 .25 0.35

S.............................................................................. 3.000 7.00 0 1.00 10.00 .25 1.60 3.00 .25 0.60

1................................... 10,000 14.00 0 1.40 20.00 .25 3.10 7.00 .25 1.20

125,000 114.00 0 16.20 151.00 .25 21.60 37.00 .25 5.40

4 .............................................................................. . 10.000 51.00 0 7.20 74.00 .25 10.70 23.00 .25 3.50

Source: Cost Analysis for Hazardous Waste Tank Rule: June 1986.NOTE:-Full secondary containment costs include a lined concrete pad and curbing beneath the tank. The 275 and 550 gallon tanks have 15 feet of piping per tank, the remaining tanks

have 50 feet per tank.

Because we assume that undergroundtanks are retrofitted with full secondarycontainment by replacement with adouble-walled tank, we have includedthe cost of corrosion protection. Weassume that aboveground tanks areretrofitted with secondary containmentby installing a lined concrete pad andberm; therefore, the tank is not incontact with the soil and does notrequire corrosion protection. As thetables indicate, there is a wide variationin the incremental cost of the new tanksecondary containment requirement,depending upon the type, size, andnumber of tanks.

To estimate the economic impactsassociated with the final regulatorycosts, the Agency collected financialdata for each facility in the RIA surveydata base. By analyzing publicly-available financial'information, theAgency assessed the ability of affectedfacilities, firms, and industries to bearthe increased costs of the finalregulations. The Agency first estimatednet income of each firm in the OSW RIAdata base. To determine if thecompliance costs for a facility aresignificant, EPA investigated whetherthe ratio of annualized compliance coststo firm net income is greater than 20percent. If so, a firm is identified aspotentially having financial difficultiesin complying with the regulations.

For firms identified as such, EPAexamined each firm's financial profile todetermine whether the firm has financialdifficilty e.xclusive of the compliancecosts, or has assets that could beredirecte'd to finance compliance with

the final requirements. For this analysis,EPA determined the extent of impactson facilities for the Nation.

To determine whether a substantialnumber of small businesses would besignificantly affected by the. finalregulations, EPA compared averagecompliance costs for small businesses tonet income levels of model smallbusinesses for each affected industry.This analysis allowed the Agency todetermine at what level compliancecosts would be greater than 20 percentof the model small business net income.Based on a distribution of smallbusiness net incomes for each industry,the Agency estimated whether asubstantial number of small businessesthat must comply with the regulationsmay incur financial hardship as a result.If less than 20 percent of the smallbusinesses are predicted to incursignificant impacts, then EPA does notconsider the regulations to result insignificant small business impacts.

Similarly, to examine the impacts onthe small quantity generator population,the Agency compared the range ofpotential compliance costs to modelplant financial characteristics. TheAgency used model plants for SQGfacilities because actual facilityfinancial data for the SQG surveysample were generally unavailable.These model plants differ in terms of thetypes and quantities of wastesgenerated, and in their financialcharacteristics. Two size categories of:model plants were used to represent 42industries: establishments with 1-9

employees and those with 10-49employees.

B. Cost and Economic Impacts

EPA estimated total Nationalcompliance costs in four categories. Thefirst category of compliance costs areinitial costs. Initial costs are thosewhich are incurred in the first year, butare not depreciable capital costs. Anexample of an initial cost is the cost ofdeveloping closure and post-closurecontingency plans. The second categoryof compliance costs are the capitalcosts. Tank facilities may incur thesecosts in the first year or they may occurperiodically overthe life of the tank.Capital costs are depreciable costs. Anexample of a capital cost is the cost of asecondary containment system.

Third, EPA estimated operating andmaintenance (O&M) compliance costs.O&M costs are incurred by tankfacilities periodically during the year.These compliance costs include periodicinspections of monitoring equipment.Finally, EPA estimated annualized costs.Annualized costs represent the initialand capital costs on a yearly basis overthe assumed 20-year life of the tank plusthe O&M costs. All costs are calculatedon a net present value and pre-tax basis.Net present value allows a standardcomparison for varying compliancecosts over time. Pre-tax costs representthe full compliance costs faced by theregulated.community prior to receiving.tax savings from capital depreciation.

The Agency estimated the total initialcompliance costs of Parts 264 and 265for existing permitted and interim status

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hazardous waste tanks to beapproximately $5.0 million, total capitalcosts to be about $120.0 million, and thetotal O&M costs to be about $6.0 million.EPA estimates the total capitalcompliance costs of Part 262 foraccumulation tanks subject to- thisregulation to be about $31.6 million andthe O&M costs to be about $2.8 million.Because owner/operators ofaccumulation tanks are not required todevelop closure and post-closurecontingency plans, no initial compliancecosts will be incurred by this portion ofthe regulated community.

To estimate the impacts of these final.rule revisions, the Agency annualizedbefore-tax facility compliance costs bythe appropriate industry real cost ofcapital. National before-tax costs arethe sum of the weighted facilityannualized costs. The Agency estimatedthe annualized cost of Parts 264 and 265amendments to be about $23.7 millionfor approximately 1,700 storage andtreatment tank facilities in the U.S. Forthe 2,100 accumulation tank facilitiessubject to this regulation, EPA estimatedthe annualized cost of the Part 262amendments to be about $7.3 million.Thus, the national total annualized costof this final rule is about $31.0 million.

In order to assess the potentialnational cost impact for leaking tanksthat are less than 15 years old, EPAestimated the: cost assuming allhazardous waste tank systems must beprovided with full secondarycontainment immediately. Thisassumption results in a total annualizedcost for the nation of $39.0 million, anannualized increase of about $8.0million. More realistically, if we assumethat 25 percent of the tank systems lessthan 15 years old are leaking, the totalnational annualized cost increases byabout $2.0 million to $33.0 million. Thus,even under worst case situations, thenational costs would not approach $100million. The annualized costs do nothave a large increase becauseimmediate provision of full secondarycontainment greatly reduces the O&Mcosts of integrity assessments.

The total. estimated compliance costsfor the final rule differ from those of theproposal for a number of reasons.Among the more prominent reasons arethe following: first, theregulations havechanged from requiring full secondarycontainment or the ground-watermonitoring approach implementedwithin a year, to phasing-in fullsecondary containment based on tankage. Second, above ground piping is notrequired to- have full secondary .containment for straight lengths ofpiping that are visually inspected on a

daily basis, instead of for the entirepiping system. Third, in response topublic comment, we have increased ourpiping length assumptions for tankfacilities with five or more tanks from 50feet of piping per tank to 200 feet ofpiping per tank. Fourth, we estimatecosts for accumulation tanks assumingthat their characteristics are distributedlike storage tanks, unlike at proposalwhere we showed a range of costsbased on the assumption that allaccumulation tanks are eitheraboveground or underground. Finally,for tank systems that are not required toretrofit full secondary containmentimmediately, we estimate the cost of anannual integrity assessment until thetank reaches the phase-in age.

The results of the financial analysisfor storage and treatment tank facilitiesare based on a sample of 167 storage ortreatment tank facilities with financialinformation available (out of 254 storageor treatment tank facilities in the OSWdata base). We do not expect any of thefacilities in the sample to be affectedsignificantly or to close as a result of theregulations. We base this conclusion onour screening analysis of all 167 firmsand a more thorough review of thecompliance costs and financialconditions of 18 facilities not passingour initial screening analysis. Thisreview focused on such things as therelationship of each firm's estimatedcompliance costs to total cash-flow (netincome plus non-cash expenses such asdepreciation, amortization, anddepletion) and to assets.

For 82 percent of the 167 facilities inthe sample, the annualized after-taxcompliance costs represent only onepercent or less of their firm's net income.Extrapolating these results to the nationshows similar results-81 percent of allpotentially-affected facilities nationallyare likely to incur annualizedcompliance costs that are one percent orless of their firm's net income. Thesecosts do not represent substantialeconomic impacts on the affected firms.

For accumulation tank facilities, webased our conclusions on a sample of234 facilities with financial informationavailable- (out of a total of 349accumulation tank facilities in the OSWdata base). As for the storage ortreatment tank facilities, we do notexpect any of the accumulation tankfacilities to be affected significantly orto close as a result of the regulations.This conclusion is based on ourscreening analysis of all 234 firms and amore thorough review of the compliance*costs and financial conditions of 37facilities not.passing oui initial.screening analysis. For 76 percent of the

accumulation tank facilities, annualizedafter-tax compliance costs represent onepercent-or less of their firm's net income.

Extrapolating from the results foraccumulation tank facilities in thesample to the nation shows resultssimilar to those found for the storage ortreatment tank facilities. The OSW database does not provide tankcharacteristic data for accumulationtanks by their type (e.g., above, in,. orunderground). Therefore, we assumethat the population of accumulationtanks has basically the samecharacteristics as storage tanks. Usingthis assumption, we find that 81 percentof all potentially-affected facilitiesnationally are likely to incur annualizedcompliance costs that are one percent orless of their firm's net income. Again,these costs are not substantial.

The model estimated potentialimpacts on small quantity generatorhazardous waste tank facilities basedon the assumption that they would besubject to the Part 264 requirements ofthe final rule. The estimated costassuming the SQG facilities had twounderground tanks would result in 21out of 84 model facilities experiencingsignificant impacts. The annualized costassuming SQG facilities had twoaboveground tanks would result in fourmodel facilities experiencing significantimpacts. Finally, the annualized costassuming SQG facilities had oneaboveground tank and one undergroundtank would result in 23 model facilitiesexperiencing significant impacts.

The economic effects of the hazardouswaste tank regulations on SQGs that arerequired to meet the Part 264 standardswould vary widely from facility tofacility depending upon financialstrength, quantity of waste, number andtype of tanks, current wastemanagement practices, and changesrequired to comply with the regulations.Certain SQGs, given the variability oftheir financial strength and potentiallack of waste management alternatives,may incur significant adverse financialeffects. Because of data limitations,however, it is not possible to determinethe frequency of these situations.

The economic analysis for permittedor interim status small quantitygenerator tank system facilities assumedthat the facilities are all smallbusinesses. Although these results seemto indicate that impacts may besignificant for some small quantitygenerators that must comply withinterim status and permittingrequirements, a Regulatory FlexibilityAnalysis is not necessary because theAgency does not expect a substantialnumber of small. businesses to be

I I25468




significantly affected. The mostimportant reason for this is that SQGfacilities have accumulation tanks thatwill not be subject to this regulation.Additional reasons why the impacts onSQG facilities will be significantly lessthan the model suggests are thefollowing:• Most SQG tank facilities will have

only one tank, thus reducing ourestimates of economic impacts (asensitivity analysis indicates thatcompliance costs for one permittedaboveground tank system result in zerosignificantly-affected model firms, whilethe compliance costs for one permittedunderground tank system result in fivesignificantly-affected model firms);

* SQG tank facilities make up only 10to 15 percent of the total SQGpopulation, most of which will not besignificantly affected;• None of the medium sized model

firms in any industry were significantlyaffected, and, based on the SQG surveydata, such firms are expected tocompose two-thirds of the SQG tankpopulation; and

Finally, we do not anticipate thatrequiring secondary containment fornew tank systems will result insignificant financial impacts. Theincremental costs of providingsecondary containment for new tanksystems, as shown in Tables 5 and 6, areless than the compliance costs forexisting tank systems under these newrequirements. Thus, we expect evenfewer impacts for facilities installingnew tanks than found for facilities withexisting tanks.

For example, we compared theincremental annualized cost forinstalling new small tanks in compliancewith the final rule to the model financialdata to assess potential impacts forsmall quantity generators. The resultsindicate that, at most, two model firms(of 84) may experience significantfinandial impacts as a result ofcomplying with the new tankrequirements. This is in contrast to theestimated 23 significantly-affectedmodel firms for the analysis ofcompliance with full interim status andpermitting requirements.

VIII. Supporting Documents

In preparing this final rule, the Agencyhas used many sources of data andinformation, the most significant of,which are listed below. They have beenplaced in the rulemaking docket at U.S.Environmental Protection Agency, EPARCRA Docket (Sub-basement), 401 MStreet, SW., Washington, DC 20460. Thedocket is open from 9:30 a.m. to 3:30p.m., Monday through Friday, except forFederal holidays. The public must make

an appointment to review docketmaterials by calling Mia Zmud at (202)475-9327 or Kate Blow at (202) 382-4675.

The Agency has used the backgrounddocuments supporting the existingRCRA tank regulation, the Agency'sJune 16, 1985, proposal to amend theexisting RCRA tank regulation, andother information gathered sinceproposal.

The major sources of information arethe following, which are available forviewing only at the EPA RCRA Docket:

1. "Hazardous Waste Tanks RiskAnalysis," ICF, Incorporated and Pope-ReidAssociates, Inc. (June 1986). The objective ofthis study was to analyze and assess thehuman health risks associated with releasesof contaminants from hazardous waste tanks.An analysis included the population of fourtank categories: RCRA-permitted storagetanks; treatment tanks that are not exemptunder EPA's wastewater treatment tank(WWT) exemption; small quantity generator(SQG} tanks; and accumulation tanks (tanksthat store waste for less than 90-days andare, therefore, not required to obtain anRCRA permit). The analysis focused on fiveregulatory scenarios, namely, no revisedregulatory requirement (baseline):secondary), containment; partial secondarycontainment and ground-water monitoring),corrosion protection for portions of steeltanks in contact with the soil: and leaktesting and ground-water monitoring.

2. Public Comments on the June 26, 1985proposal to revise the existing RCRA tankstandards. All the public comments receivedon the revised tank standards proposal areincluded in the docket at EPA Headquarters.These comments were considered by EPA indeveloping today's final rule.

3. Response to Public Comments on theRevised Hazardous Waste Storage andTreatment Tank Standards, Versar Inc. (June1986). This document provides an analysis ofpublic comments received in response to theproposed revised standards for hazardouswaste storage and treatment tank systems.The analysis identified 54 issues in which avariety of comments by 89 commenters wereidentified and classified and the Agency'sresponse was documented.

4. "Assessment of the TechnicalEnvironmental and Safety Aspects of Storageof Hazardous Waste in Underground Tanks,"SCS Engineers, (February 1984). Theobjectives of this study were to define currentpractices for hazardous waste storage inunderground tanks; evaluate these practicesin relation to data on spills and damages andbest engineering judgment; estimate therelative probability and magnitude ofreleases from underground tanks, andexamine appropriate alternatives forprevention and/or migration of releases.

5. "Underground Tank Leak DetectionProgram Status Report," California RegionalWater Quality Control Board-San FranciscoBay Region, (October 1983). The objectives ofthis study were to identify geographical areas(within the San Francisco Bay region) wherethe ground water is of particular concern,develop a facilities information

questionnaire; develop subsurfaceinvestigation guidelines; identify priorityfacilities; and request the completion ofsubsurface investigations. The investigationfocused on industrial facilities storinghazardous materials including: acids, metals,resins, solvents, and fuels. Included in thestudy were facilities with undergroundcontainment including: product storage tanks,waste tanks and sumps, fuel tanks, andpiping systems associated with these tanks.The information includes questionnaire data'on 1,918 facilities as well as the results ofsubsurface investigations at 80 facilities.

6. "Quarterly Status Report on ToxicCleanup Cases," State of California-California Regional Water Quality ControlBoard-San Francisco Bay Region (March1986). This report includes a brief summaryand status of 144 toxic cleanup casescurrently in progress. Information includesthe extent of contamination and descriptionof remedial action.

7. "Results of API Tank and Piping LeakSurvey," American Petroleum Institute (1981).This study includes the statistical results of1,717 completed "Tank and Piping LeakSurvey Questionnaire" forms. The survey'sprimary purpose was to obtain informationon the exact location of perforations in tanksto support the effectiveness of various tanktesting procedures.

6. "Analysis of Causes of Release IncidentsBased on the Underground Storage TankRelease Incidents Data Base," Versar, Inc.(June 1986). The objectives of this study wereto investigate the causes of release incidentsbased on available information on 12,500underground storage tank release incidents.

9. "Underground Motor Fuel Storage Tanks:A National Survey," Volumes I and I,USEPA, Office of Pesticides and ToxicSubstances, Washington, DC (EPA 560/6-86--013) (June 1986).

IX. Executive Order 12291

Sections 2 and 3 of Executive Order12291 (46 FR 13193; February 9, 1981)require that a regulatory agencydetermine whether a new regulation willbe "major" and, if so, that a RegulatoryImpact Analysis be conducted. A majorrule is defined as one that is likely toresult in: (1) an annual effect on theeconomy of $100 million or more; (2) amajor increase in costs and prices forconsumers, individual industries,Federal, State, and local governmentagencies, or geographic regions; or (3)significant adverse effects oncompetition, employment, investment,productivity, innovation, or on theability of the United States-basedenterprises to compete with foreign-based enterprises in domestic or exportmarkets.

As previously discussed in section VIIof this preamble, today's finalregulations will have none of the aboveeffects. Because the final amendments tothe regulations applicable to RCRA tankfacilities do not meet the definition of a

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2?~17flFederal Resister I Vol. 51. No. 134 / Monday, July 14, 1986 / Rules and Regulations

major regulation, the Agency has notconducted a Regulatory ImpactAnalysis. EPA has prepared backgroundinformation supporting thisdetermination; this documentation is inthe Economic Impact Analysis Report,which may be examined at the RCRAPublic Docket Office.

X. Paperwork Reduction Act

The information collectionrequirements contained in this rule havebeen approved by the Office ofManagement and Budget (OMB) underthe Paperwork Reduction Act of 1980, 44U.S.C. 3501 et seq., and have beenassigned OMB control numbers 2050-0050.

XI. Regulatory Flexibility Act

Pursuant to the Regulatory FlexibilityAct (U.S.C. 601 et seg.), whenever anAgency is required to publish a generalnotice of rulemaking for any proposed orfinal rule, it must prepare and makeavailable for public comment aregulatory flexibility analysis thatdescribes the impact of the rules onsmall entities (i.e., small business, smallorganizations, and small governmentaljurisdictions). No regulatory flexibilityanalysis is required, however, if thehead of the Agency certifies the rule willnot have a significant economic impacton a-substantial number of smallentities. EPA has conducted an analysisof the impacts on small businesses,which is included in the EconomicImpact Analysis Report (EIAR).

EPA has established guidelines fordetermining whether a regulatoryflexibility analysis (RFA) is required toaccompany a rulemaking package. Theguidelines state that if at least 20percent of the universe of "smallentities" are affected by the rule, then aRFA is required. In addition, the EPAcriteria should be applied to evaluate ifa regulation will have a "significantimpact" on small entities. If any one ofthe following four criteria is met, theregulation should be assumed to have a"significant impact":

(1) Annual compliance costs willincrease the relevant production costsfor small entities by more than 5percent;

(2) The ratio of compliance costs to.sales will be 10 percent higher for smallentities than for large entities;

(3) Capital costs of compliance willrepresent a significant portion of thecapital available to small entities, takinginto acc3unt internal cash flow plusexternal financing capabilities; or

(4) The costs of the regulation willlikely result in closures of small entities.The Agency used a cash flow analysis toexamine the extent to which the

compliance costs will represent apotentially significant portion of capital.available to small entities and thelikelihood of small business plantclosures.

To determine whether a substantialnumber of small businesses would besignificantly affected by the finalregulations, EPA compared averagecompliance costs for small businesses tonet income levels of model smallbusiness financial characteristics foreach affected industry. This analysisallowed the Agency to determine atwhat level compliance costs would begreater than 20 percent of the modelsmall business net income, therebyindicating significant impacts. Based ona distribution of small business netincomes for each industry, the Agencyestimated whether a substantial numberof small businesses that must complywith the regulations may incur financialhardship as a result. If less than 20percent of the small businesses withineach affected industry are predicted toincur significant impacts, then EPA doesnot consider the regulations to result insignificant small business impacts.

Similarly, to examine the impacts ofthe affected small quantity generatorpopulation, the Agency compared therange of'potential compliance costs tomodel plant financial characteristics.The Agency used model plants for SQGfacilities because actual. facilityfinancial data for the SQG surveysample were generally unavailable.These model plants differ in terms of thetypes and quantities of wastesgenerated, and in their financialcharacteristics. Two size categories ofmodel plants were used to represent 42industries: establishments with 1-9employees and those with 10-49employees.

The analysis of the effects of theregulations on small businesses showsthat less than 20 percent of potentiallyaffected small businesses within eachaffected industry nationwide are likelyto be significantly affected by theregulations. In addition, the plantclopure analysis indicated that therewould be no plant closures as a result ofthe regulations. Finally, our analysis ofsmall quantity generators suggests thatvery few and certainly less than 20percent of the affected small quantitygenerators will be significantly affectedby this rule because most SQG tankfacilities will not require interim statusor storage permits.

The Economic Impact Analysis Report(EIAR) for this rulemaking provides amore detailed discussion of theAgency's methodology for, and findingsfrom, assessing small business impactsattributable to the hazardous waste tank

rule. The EIAR is available for publicviewing in the docket for today'srulemaking. On the basis of the analysisconducted, EPA has determined that thisrulemaking will not have significanteconomic impact on a substantialnumber of small entities.

List of Subjects

40 CFR Part 260

Administrative practice andprocedure, Confidential businessinformation. Hazardous materials,Waste treatment and disposal.

40 CFR Part 261

Intergovernmental relations,Hazardous materials. Waste treatmentand disposal, Recycling.

40 CFR Part 262

Hazardous materials, Wastetreatment and disposal, Recycling.

40 CFR Part 264

Hazardous materials, Packaging andcontainers, Reporting and recordkeepingrequirements, Security measures, Suretybonds. Waste treatment and disposal.

40 CFR Part 265

Hazardous materials, Packaging andcontainers, Reporting and recordkeepingrequirements' Security measures, Suretybonds, Waste treatment and disposal,Water supply.

40 CFR Part 270

Administrative practice andprocedure, Confidential businessinformation, Hazardous materialstransportation, Hazardous waste,Reporting and recordkeepingrequirements, Water pollution control,Water supply.

40 CFR Part 271

Administrative practice andprocedure, Confidential businessinformation, Hazardous materialstransportation, Hazardous waste, Indianlands, Intergovernmental relations,Penalties, Reporting and recordkeepingrequirements, Water pollution control.Water supply.

Dated: June 30,1986.Lee M. Thomas,Administrator.

For the reasons set out in thepreamble, Title 40 of the Code of FederalRegulations is amended as follows:

PART 260-HAZARDOUS WASTEMANAGEMENT SYSTEM: GENERAL

40 CFR Part 260 is amended asfollows:

95470 Federal Reuister / Vol. 51, No. 134 / Monday, July 14, 1.986 / Rules and RegulationsKd fl




1. The authority citation for Part 260 isrevised to read as follows:

Authority: Secs. 1006, 2002(a), 3001 through3007, 3010, 3014, 3015, 3017, 3016, and 3019 ofthe Solid Waste Disposal Act, as amended bythe Resource Conservation and Recovery Actof 1976, as amended (42 U.S.C. 6905, 6912(a),6921 through 6927, 6930, 6934, 6935, 6937, 6938,and 6939).

2. Section 260.10 is amended byadding the following terms anddefinitions in alphabetical order:

§260.10 Definitions.

"Aboveground tank" means a devicemeeting the definition of "tank" in§ 260.10 and that is situated in such away that the entire surface area of thetank is completely above the plane ofthe adjacent surrounding surface andthe entire surface area of the tank(including the tank bottom) is able to bevisually inspected.* * * * *

"Ancillary equipment" means anydevice including, but not limited to, suchdevices as piping, fittings, flanges,valves, and pumps, that is used todistribute, meter, or control the flow ofhazardous waste from its point ofgeneration to'a storage or treatmenttank(s), between hazardous wastestorage and treatment tanks to a point ofdisposal onsite, or to a point of shipmentfor disposal off-site.

"Component" means either the tank orancillary equipment of a tank system.

"Corrosion expert" means a personwho, by reason of his knowledge of thephysical sciences and the principles ofengineering and mathematics, acquiredby a professional education and relatedpractical experience, is qualified toengage in the practice of corrosioncontrol on buried or submerged metalpiping systems and metal tanks. Such aperson must be certified as beingqualified by the National Association ofCorrosion Engineers (NACE) or be aregistered professional engineer whohas certification or licensing thatincludes education and experience incorrosion control on buried orsubmerged metal piping systems andmetal tanks.* * * * *

"Existing tank system" or "existingcomponent" means a tank system orcomponent that is used for the storageor treatment of hazardous waste andthat is in operation, or for whichinstallation has commenced on or priorto luly 14, 1986. Installation will beconsidered to have commenced if theowner or operator has obtained all

Federal, State, and local approvals orpermits necessary to begin physicalconstruction of the site or installation ofthe tank system and if either (1) acontinuous on-site physical constructionor installation program has begun, or (2)the owner or operator has entered intocontractual obligations-which cannotbe canceled or modified withoutsubstantial loss-for physicalconstruction of the site or installation ofthe tank system to be completed withina reasonable time.

"Inground tank" means a devicemeeting the definition of "tank" in§ 260.10 whereby a portion of the tankwall is situated to any degree within theground, thereby preventing visualinspection of that external surface areaof the tank that is in the ground.

"Installation inspector" means aperson who, by reason of his knowledgeof the physical sciences and theprinciples of engineering, acquired by aprofessional education and relatedpractical experience, is qualified tosupervise the installation of tanksystems.

"Leak-detection system" means asystem capable of detecting the failureof either the primary or secondarycontainment structure or the presence ofa release of hazardous waste oraccumulated liquid in the secondarycontainment structure. Such a systemmust employ operational controls (e.g.,daily visual inspections for releases intothe secondary containment system ofaboveground tanks) or consist of aninterstitial monitoring device designedto detect continuously andautomatically the failure of the primaryor secondary containment structure orthe presence of a release of hazardouswaste into the secondary containmentstructure.

"New tank system" or "new tankcomponent" means a tank system orcomponent that will be used for thestorage or treatment of hazardous wasteand for which installation hascommenced after July 14, 1986; except,however, for purposes of § 264.193(g)(2)and § 265.193(g)(2), a new tank system isone for which construction commencesafter July 14, 1986. (See also "existingtank system.")

"Onground tank" means a devicemeeting the definition of "tank" in§ 260.10 and that is situated in such away that the bottom of the tank is on thesame level as the adjacent surrounding

surface so that the external tank bottomcannot be visually inspected.

"Sump" means any pit or reservoirthat meets the definition of tank andthose troughs/trenches connected to itthat serves to collect hazardous wastefor transport to hazardous wastestorage, treatment, or disposal facilities.

"Tank system" means a hazardouswaste storage or treatment tank and itsassociated ancillary equipment andcontainment system.

"Underground tank" means a devicemeeting the definition of "tank" in§ 260.10 whose entire surface area istotally below the surface of and coveredby the ground.

"Unfit-for use tank system" means atank system that has been determinedthrough an integrity assessment or otherinspection to be no longer capable ofstoring or treating hazardous wastewithout posing a threat of release ofhazardous waste to the environment.

"Zone of engineering control" meansan area under the control of the owner/operator that, upon detection of ahazardous waste release, can be readilycleaned up prior to the release ofhazardous waste or hazardousconstituents to ground water or surfacewater.

PART 261-IDENTIFICATION ANDLISTING OF HAZARDOUS WASTE

3. The authority citation for Part 261continues to read as follows:

Authority: Secs. 1006, 2002(a), 3001, and3002 of the Solid Waste Disposal Act, asamended by the Resource Conservation andRecovery Act of 1976, as amended (42 U.S.C.6905, 6912(a), 6921, and 6922).

4. Section 261.4 is amended by addingparagraph (a)(8] to read as follows:

§ 261.4 Exclusions.(a) * * *(8) Secondary materials that are

reclaimed and returned to the originalprocess or processes in which they weregenerated where they are reused in theproduction process provided:

(i) Only tank storage is involved, andthe entire process through completion ofreclamation is closed by being entirelyconnected with pipes or othercomparable enclosed means ofconveyance;

(ii) Reclamation does not involvecontrolled flame combustion (such as

25471




occurs in boilers, industrial furnaces, orincinerators);

(iii) The secondary materials arenever accumulated in such tanks forover twelve months without beingreclaimed; and

(iv) The reclaimed material is not usedto produce a fuel, or used to produceproducts that are used in a mannerconstituting disposal.

PART 262-STANDARDS APPLICABLETO GENERATORS OF HAZARDOUSWASTE


5. The authority citation for Part 262 isrevised to read as follows:

Authority: Secs. 1006. 2002. 3001. 3002, 3003.3004, 3005, and 3017 of the Solid WasteDisposal Act, as amended by the ResourceConservation and Recovery Act of 1976, asamended (42 U.S.C. 6906. 6912, 6922, 6923.6924, 6925, and 6937).

6. Section 262.34 is amended byrevising paragraphs (a)(1) and (d)(2), byredesignating existing paragraphs (d)(3)and (d)(4) as (d)(4) and (d)(5),respectively, and by adding a newparagraph (d)(3), as follows:

§ 262.34 Accumulation time.(a) Except as provided in paragraphs

(d), (e). and (f) of this section, agenerator may accumulate hazardouswaste on-site for 90 days or less withouta permit or without having interimstatus, provided that:

(1) The waste is placed in containersand the generator complies with SubpartI of 40 CFR Part 265, or the waste isplaced in tanks and the generatorcomplies with Subpart J of 40 CFR Part265, except § 265.197(c), and § 265.200. Inaddition, such a generator is exemptfrom all the requirements in Subparts Gand H of 40 CFR Part 265, except for§ 265.111 and § 265.114.

(d) *(2) The generator complies with the

requirements of Subpart I of Part 265,except § 265.176;

(3) The generator complies with therequirements of § 265.201 in Subpart J ofPart 265;

PART 264-STANDARDS FOROWNERS AND OPERATORS OFHAZARDOUS WASTE TREATMENT,STORAGE, AND DISPOSALFACILITIES


7. The Authority citation for Part 264is revised to read as follows:

Authority: Secs. 1006, 2002, 3004, and 3005of the Solid Waste Disposal Act as amendedby the Resource Conservation and RecoveryAct of 1976, as amended (42 U.S.C. 6905,6912(a), 6924, and 6925).

8. The Table of Contents and headingof Part 264, Subpart J-Tanks, is revisedto read as follows:

Subpart J-Tank Systems

Sec.264.190 Applicability.264.191 Assessment of existing tank

system's integrity.264.192 Design and installation of new tank

systems or components.264.193 Containment and detection of

releases.264.194 General operating requirements.264.195 Inspections.264.196 Response to leaks or spills and

disposition of leaking or unfit-for-usetank systems.

264.197 Closure and post-closure care.264.198 Special requirements for ignitable or

reactive wastes.264.199 Special requirements for

incompatible wastes.

9. Section 264.15 is amended byrevising paragraph (b)(4) to read asfollows:

§ 264.15 General inspection requirements.

(b) ...(4) The frequency of inspection may

vary for the items on the schedule.However, it should be based on the rateof possible deterioration of theequipment and the probability of anenvironmental or human health incidentif the deterioration or malfunction ofany operator error goes undetectedbetween inspections. Areas subject tospills, such as loading and unloadingareas, must be inspected daily when inuse. At a minimum, the inspectionschedule must include the terms andfrequencies called for in § § 264.174,264.193, 264.195, 264.226, 264.253, 264.254.264.303, and 264.347, where applicable.


§ 264.73 Operating record.

(b) "

(6) Monitoring, testing, or analyticaldata where required by Subpart F and§ § 264.191, 264.193, 264.195, 264.226,264.253, 264.254, 264.276, 264.278, 264.280,264.303. 264.309, and 264.347.

11. Section 264.110 is amended byadding a new paragraph (b)(3) to read asfollows:

§ 264.110 Applicability.

(b) * * *

(3) Tank systems that are requiredunder § 264.197 to meet the requirementsfor landfills.

12. Section 264.140 is amended byadding a new paragraph (b)(3) to read asfollows:


(b) ...

(3) Tank systems that are requiredunder § 264.197 to meet the requirementsfor landfills.

13. The Subpart J-Tank Systemsrequirements are amended by revisingthe Subpart as follows:



The requirements of this Subpartapply to owners and operators offacilities that use tank systems forstoring or treating hazardous wasteexcept as otherwise provided inparagraphs (a) and (b) of this section orin § 264.1 of this part.

(a) Tanks that are used to store ortreat hazardous waste which containsno free liquids and are situated inside abuilding with an impermeable floor areexempted from the requirements in§ 264.193. To demonstrate the absenceor presence of free liquids in the stored/treated waste. EPA Method 9095 (PaintFilter Liquids Test) as described in "TestMethods for Evaluating Solid Wastes,Physical/Chemical Methods" (EPAPublication No. SW-846) must be used.

(b) Tanks, including sumps, as definedin § 260.10, that serve as part of asecondary containment system to collector contain releases of hazardous wastesare exempted from the requirements in§ 264 193 of this subpart.

(Information collection requirementcontained in paragraph (a) was approved bythe Office of Management and Budget undercontrol number 2050-0050.)

§ 264.191 Assessment of existing tanksystem's integrity.

(a) For each existing tank system thatdoes not have secondary containmentmeeting the requirements of § 264.193,the owner or operator must determinethat the tank system is not leaking or isunfit for use. Except as provided inparagraph (c) of this section, the owneror operator must obtain and keep on fileat the facility a written assessment

25472




reviewed and certified by anindependent, qualified registeredprofessional engineer, in accordancewith § 270.11(d), that attests to the tanksystem's integrity by January 12, 1988.

(b) This assessment must determinethat the tank system is adequatelydesigned and has sufficient structuralstrength and compatibility with thewaste(s) to be stored or treated, toensure thatit will not collapse, rupture,or fail. At a minimum, this assessmentmust consider the following:(1) Design standard(s), if available,

according to which the tank andancillary equipment were constructed;

(2) Hazardous characteristics of thewaste(s) that have been and will behandled;

(3) Existing corrosion protectionmeasures;

(4) Documented age of the tanksystem, if available (otherwise, anestimate of the age); and

(5) Results of a leak test, internalinspection, or other tank integrityexamination such that:

(i) For non-enterable undergroundtanks, the assessment must include aleak test that is capable of taking intoaccount the effects of temperaturevariations, tank end deflection, vaporpockets, and high water table effects,and

(ii) For other than non-enterableunderground tanks and for ancillaryequipment, this assessment must includeeither a leak test, as described above, orother integrity examination, that iscertified by an independent, qualified,registered professional engineer inaccordance with § 270.11(d), thataddresses cracks, leaks, corrosion, anderosion.

[Note.-The practices described in theAmerican Petroleum Institute (API)Publication, Guide for Inspection of RefineryEquipment, Chapter XII, "Atmospheric andLow-Pressure Storage Tanks," 4th edition,1981. may be used, where applicable, asguidelines in conducting other than a leaktest.l

(c) Tank systems that store or treatmaterials that become hazardous wastessubsequent to July 14, 1986, mustconduct this assessment within 12months after the date that the wastebecomes a hazardous waste.

(d) If, as a result of the assessmentconducted in accordance withparagraph (a), a tank system is found to,be leaking or unfit for use, the owner oroperator must comply with therequirements of § 264.196.

Approved by the Office of Managementand Budget under control number 2050-0050.)

§ 264.192 Design and Installation of newtank systems or components.

(a) Owners or operators of new tanksystems or components must obtain andsubmit to the Regional Administrator, attime of submittal of Part B information,a written assessment, reviewed andcertified by an independent, qualifiedregistered professional engineer, inaccordance with § 270.11(d), attestingthat the tank system has sufficientstructural integrity and is acceptable forthe storing and treating of hazardouswaste. The assessment must show thatthe foundation, structural support,seams, connections, and pressurecontrols (if applicable) are adequatelydesigned and that the tank system hassufficient structural strength,compatibility with the waste(s) to bestored or treated, and corrosionprotection to ensure that it will notcollapse, rupture, or fail. Thisassessment, which will be used by theRegional Administrator to review andapprove or disapprove the acceptabilityof the tank system design, must include,at a minimum, the following information:

(1) Design standard(s) according towhich tank(s) and/or the ancillaryequipment are constructed;

(2) Hazardous characteristics of thewaste(s) to be handled;

(3) For new tank systems orcomponents in which the external shellof a metal tank or any external metalcomponent of the tank system will be incontact with the soil or with water, adetermination by a corrosion expert of:

(i) Factors affecting the potential forcorrosion, including but not limited to:

(A) Soil moisture content;(B) Soil pH;(C) Soil sulfides level;

.(D) Soil resistivity;(E) Structure to soil potential;(F) Influence of nearby underground

metal structures (e.g., piping);(G) Existence of stray electric current;(H) Existing corrosion-protection

measures (e.g., coating, cathodicprotection), and

(ii) The type and degree of externalcorrosion protection that are needed toensure the integrity of the tank systemduring the use of the tank system orcomponent, consisting of one or more ofthe following:

(A) Corrosion-resistant materials ofconstruction such as special alloys,fiberglass reinforced plastic, etc.;

(B) Corrosion-resistant coating (suchas epoxy, fiberglass, etc.) with cathodicprotection (e~g., impressed current orsacrificial anodes); and

(C) Electrical isolation devices such asinsulating joints, flanges, etc. -

(Note.-The practices described in theNational Association of Corrosion Engineers

(NACE) standard. "Recommended Practice(RP-02-85)--Control of External Corrosion onMetallic Buried, Partially Buried, or •Submerged Liquid Storage.Systems," and theAmerican Petroleum Institute (API)Publication 1632, "Cathodic Protection ofUnderground Petroleum Storage Tanks andPiping Systems," may be used, whereapplicable, as guidelines in providingcorrosion protection for tank systems.)

(4] For underground tank systemcomponents that are likely to beadversely affected by vehicular traffic, adetermination of design or operationalmeasures that will protect the tanksystem against potential damage; and

(5) Design considerations to ensurethat:

(i) Tank foundations will maintain theload of a full tank;

(ii) Tank systems will be anchored toprevent flotation or dislodgment wherethe tank system is placed in a saturatedzone, or is located within a seismic faultzone subject to the standards of§ 264.18(a); and

(iii) Tank systems will, withstand theeffects of frost heave.

(b) The owner or operator of a newtank system must ensure that properhandling procedures are adhered to inorder to prevent damage to the systemduring installation. Prior to covering,enclosing, or placing a new tank systemor component in use, an independent,qualified installation inspector or anindependent, qualified, registeredprofessional engineer, either of whom istrained and experienced in the properinstallation of tank systems or.component, must inspect the system forthe presence of any of the followingitems:

(1) Weld breaks-(2) Punctures;(3) Scrapes of protective coatings;(4) Cracks;(5) Corrosion;(6) Other structural damage or

inadequate construction/installation.All discrepancies must be remediedbefore the tank system is covered,enclosed, or placed in use.

(c) New tank systems or componentsthat are placed underground and thatare backfilled must be provided with abackfill material that is a noncorrosive,porous, homogeneous substance andthat is installed so that the backfill isplaced completely around the tank andcompacted to ensure that the tank andpiping are fully and uniformlysupported.

(d) All new tanks and ancillaryequipment must be tested for tightnessprior to being covered, enclosed, orplaced in use. If a tank system is foundnot to be tight, all repairs necessary to

25473




remedy the leak(s) in the system mustbe performed prior to the tank systembeing covered, enclosed, or placed into 'use.

(e) Ancillary equipment must besupported and protected againstphysical damage and excessive stressdue to settlement, vibration, expansion.or contraction.

jNote.-The piping system installationprocedures described in American PetroleumInstitute (API) Publication 1615 [November1979). "Installation of Underground PetroleumStorage Systems," or ANSI Standard B31.3."Petroleum Refinery Piping," and ANSIStandard B31.4 "Liquid PetroleumTransportation Piping System," may be used.where applicable, as guidelines for properinstallation of piping systems.]

(f) The owner or operator mustprovide the type and degree of corrosionprotection recommended by anindependent corrosion expert, based onthe information provided underparagraph (a)(3) of this section, or othercorrosion protection if the RegionalAdministrator believes other corrosionprotection is necessary to ensure theintegrity of the tank system during useof the tank system. The installation of acorrosion protection system that is fieldfabricated must be supervised by anindependent corrosion expert to ensureproper installation.

(g) The owner or operator must obtainand keep on file at the facility writtenstatements by those persons required tocertify the design of the tank system andsupervise the installation of the tanksystem in accordance with therequirements of paragraphs (b) through(f) of this section, that attest that thetank system was properly designed andinstalled and that repairs', pursuant toparagraphs (b) and (d) of this section,were performed. These writtenstatements must also include thecertification statement as required in§ 270.11(d) of this Chapter.(Information collection requirementscontained in paragraphs (a] and (g) wereapproved by the Office of Management andBudget under control number 2050-0050.)

§ 264.193 Containment and detection ofreleases.

(a) In order to prevent the release ofhazardous waste or hazardousconstituents to the environment,secondary containment that meets therequirements of this section must beprovided (except as provided inparagraphs (f] and (g) of this section):

(1) For all new tank systems orcomponents, prior to their being put intoservice:

(2) For all existing tank systems usedto store or treat EPA Hazardous WasteNos. F020, F021, F022, F023, F026, and

F027, within two years after January 12.1987;

(3) For those existing tank systems of'known and documented age, within twoyears after January 12, 1987 or when thetank system has reached 15 years of age,whichever comes later: and

(4) For those existing tank systems forwhich the age cannot be documented,within eight years of January 12, 1987;but if the age of the facility is greaterthan seven years, secondarycontainment must be provided by thetime the facility reaches 15 years of age,or within two years of January 12, 1987,whichever comes later: and

(5) For tank systems that store or treatmaterials that become hazardous wastessubsequent to January 12, 1987, withinthe time intervals required inparagraphs (a)(1) through (a)(4) of thissection, except that the date that amaterial becomes a hazardous wastemust be used in place of January 12,1987.

(b) Secondary. containment systemsmust be:

(1) Designed, installed, and operatedto prevent any migration of wastes oraccumulated liquid out of the system tothe soil, ground water, or surface waterat any time during the use of the tanksystem; and

(2) Capable of detecting and collectingreleases and accumulated liquids untilthe collected material is removed.

(c) To meet the requirements ofparagraph (b) of this section, secondarycontainment systems must be at aminimum:

(1) Constructed of or lined withmaterials that are compatible with thewastes(s) to be placed in the tanksystem and must have sufficientstrength and thickness to prevent failureowing to pressure gradients (includingstatic head and external hydrologicalforces), physical contact with the wasteto which it is exposed, climaticconditions, and the stress of dailyoperation (including stresses fromnearby vehicular traffic).

(2) Placed on a foundation or basecapable of providing support to thesecondary containment system,resistance to pressure gradients aboveand below the system, and capable ofpreventing failure due to settlement,compression, or uplift;(3) Provided with a leak-detection

system that is designed and operated sothat it will detect the failure of either theprimary or secondary containmentstructure or the presence of any releaseof hazardous waste or accumulatedliquid in the secondary containmentsystem within 24 hours, or at the earliestpracticable time if the owner or operatorcan demonstrate to the Regional

Administrator that existing detectiontechnologies or site conditions will notallow detection of a release within 24hours; and

(4) Sloped or otherwise designed oroperated to drain and remove liquidsresulting from leaks, spills, orprecipitation. Spilled or leaked wasteand accumulated precipitation must beremoved from the secondarycontainment system within 24 hours, orin as timely a manner as is possible toprevent harm to human health and theenvironment, if the owner or operatorcan demonstrate to the RegionalAdministrator that removal of thereleased waste or accumulatedprecipitation cannot be accomplishedwithin 24 hours.

[Note.-If the collected material is ahazardous waste under Part 261 of thischapter. it is subject to management as ahazardous waste in accordance with allapplicable requirements of Parts 262 through265 of this chapter. If the collected material isdischarged through a point source to watersof the United States, it is subject to therequirements of sections 301, 304, and 402 ofthe Clean Water Act, as amended. Ifdischarged to a Publicly Owned TreatmentWorks (POTW), it is subject to therequirements of section 307 of the CleanWater Act, as amended. If the collectedmaterial is released to the environment, itmay be subject to the reporting requirementsof 40 CFR Part 302.1

(d) Secondary containment for tanksmust include one or more of thefollowing devices:

(1) A liner (external to the tank);(2) A vault;(3) A double-walled tank; or(4) An equivalent device as approved

by the Regional Administrator(e) In addition to the requirements of

paragraphs (b), (c), and (d) of thissection, secondary containment systemsmust satisfy the following requirements:

(1) External liner systems must be:(i) Designed or operated to contain 100

percent of the capacity of the largesttank within its boundary;

(ii) Designed or operated to preventrun-on or infiltration of precipitationinto the secondary containment systemunless the collection system hassufficient excess capacity to containrun-on or infiltration. Such additionalcapacity must be sufficient to containprecipitation from a 25-year, 24-hourrainfall event.

(iii) Free of cracks or gaps; and(iv) Designed and installed to

surround the tank completely and tocover all surrounding earth likely tocome into contact with the waste ifreleased from the tank(s) (i.e., capableof preventing lateral as well as verticalmigration of the waste).

25474




(2) Vault systems must be:(i] Designed or operated to contain 100

percent of the capacity of the largesttank within its boundary;

(ii) Designed or operated to preventrun-on or infiltration of precipitationinto the secondary containment systemunless the collection system hassufficient excess capacity to containrun-on or infiltration. Such additionalcapacity must be sufficient to containprecipitation from a 25-year, 24-hourrainfall event:

(iii) Constructed with chemical-resistant water stops in place at allJoints (if any):

(iv) Provided with an impermeableinterior coating or lining that iscompatible with the stored waste andthat will prevent migration of waste intothe concrete;

(v) Provided with a means to protectagainst the formation of and ignition ofvapors within the vault, if the wastebeing stored or treated:

(A) Meets the definition of ignitablewaste under § 262.21 of this chapter; or

(B) Meets the definition of reactivewaste under § 262.21 of this chapter, andmay form an ignitable or explosivevapor.

(vi) Provided with an exteriormoisture barrier or be otherwisedesigned or operated to preventmigration of moisture into the vault ifthe vault is subject to hydraulicpressure.

(3) Double-walled tanks must be:(i) Designed as an integral structure

(i.e., an inner tank completely envelopedwithin an outer shell) so that anyrelease from the inner tank is containedby the outer shell.

(ii) Protected, if constructed of metal,from both corrosion of the primary tankinterior and of the external surface ofthe outer shell: and

(iii) Provided with a built-incontinuous leak detection systemcapable of detecting a release within 24hours, or at the earliest practicable time,if the owner or operator candemonstrate to the RegionalAdministrator, and the RegionalAdministrator concludes, that theexisting detection technology or siteconditions would not allow detection ofa release within 24 hours.

[Note.-The provisions outlined in theSteel Tank Institute's (ST} "Standard forDual Wall Underground Steel Storage Tanks"may be used as guidelines for aspects of thedesign of underground steel double-walledtanks.],

(f) Ancillary equipment must beprovided with secondary containment(e.g., trench, jacketing, double-walledpiping) that meets the requirements of

paragraphs (b) and (c) of this sectionexcept for:

(1) Aboveground piping (exclusive offlanges, joints, valves, and otherconnections) that are visually inspectedfor leaks on a daily basis;

(2) Welded flanges, welded Joints, andwelded connections, that are visuallyinspected for leaks on a daily basis;

(3] Sealless or magnetic couplingpumps, that are visually inspected forleaks on a daily basis; and

(4) Pressurized aboveground pipingsystems with automatic shut-off devices(e.g., excess flow check valves, flowmetering shutdown devices, loss ofpressure actuated shut-off devices) thatare visually inspected for leaks on adaily basis.

(g) The owner or operator may obtaina variance from the requirements of thissection if the Regional Administratorfinds, as a result of a demonstration bythe owner or operator that alternativedesign and operating practices, togetherwith location characteristics, willprevent the migration of any hazardouswaste or hazardous constituents into theground water; or surface water at leastas effectively as secondary containmentduring the active life of the tank systemor that in the event of a release thatdoes migrate to ground water or surfacewater, no substantial present orpotential hazard will be posed to humanhealth or the environment. Newunderground tank systems may not, pera demonstration in accordance withparagraph (g)(2) of this section, beexempted from the secondarycontainment requirements of thissection.(1) In deciding whether to grant a

variance based on a demonstration ofequivalent protection of ground waterand surface water, the RegionalAdministrator will consider:

(i) The nature and quantity of thewastes; '

(ii) The proposed alternate design andoperation;

(iii) The hydrogeologic setting of thefacility, including the thickness of soilspresent between the tank system andground water, and

(iv) All other factors that wouldinfluence the quality and mobility of thehazardous constituents and the potentialfor them to migrate to ground water orsurface water

(2) In deciding whether to grant avariance based on a demonstration ofno substantial present or potentialhazard, the Regional Administrator willconsider:

(i) The potential adverseeffects onground water, surface water, and landquality taking into account:-

(A) The physical and chemicalcharacteristics of the waste in the tanksystem, including its potential formigration.

(B) The hydrogeologicalcharacteristics of the facility andsurrounding land,

(C) The potential for health riskscaused by human exposure to wasteconstituents,

(D) The potential for damage towildlife, crops, vegetation, and physicalstructures caused by exposure to wasteconstituents, and

(E) The persistence and permanenceof the potential adverse effects;

(ii) The potential adverse effects of arelease on ground-water quality, takinginto account:

(A) The quantity and quality ofground water and the direction ofground-water flow,

(B) The proximity and withdrawalrates of ground-water users,

(C) The current and future uses ofground water in the area, and

(D) The existing quality of groundwater including other sources ofcontamination and their cumulativeimpact on the ground-water quality;

(iii) The potential adverse effects of arelease on surface water quality, takinginto account:


(B) The patterns of rainfall in theregion,

(C) The proximity of the tank systemto surface waters,

(D) The current and future uses ofsurface waters in the area and anywater quality standards established forthose surface waters, and

(E) The existing quality of surfacewater, including other sources ofcontamination and the cumulativeimpact on surface-water quality; and

(iv) The potential adverse effects of arelease on the land surrounding the tanksystem, taking into account:

(A) The patterns of rainfall in theregion, and

(B) The current and future uses of thesurrounding land.

(3) The owner or operator of a tanksystem, for which a variance fromsecondary containment had beengranted in accordance with therequirements of paragraph (g)(1) of thissection, at which a release of hazardouswaste has occurred from the primarytank system but has not migratedbeyond the zone of engineering control(as established in the variance), must:

(i) Comply with the requirements of§ 264.196, except paragraph (d), and

25475




(ii) Decontaminate or removecontaminated soil to the extentnecessary to:

(A) Enable the tank system for whichthe variance was granted to resumeoperation with the capability for thedetection of releases at least equivalentto the capability it had prior to therelease; and.

(B) Prevent the migration of hazardouswaste or hazardous constituents toground water or surface water- and

(iii) If contaminated soil cannot beremoved or decontaminated inaccordance with paragraph (g13)(ii) ofthis section, comply with therequirement of § 264.197(b).

(4) The owner or operator of a tanksystem, for which a variance fromsecondary containment had beengranted, in accordance with therequirements of paragraph (g)(1) of thissection, at which a release of hazardouswaste has occurred from the primarytank system and has migrated beyondthe zone of engineering control (asestablished in the variance), must

(i) Comply with the requirements of§ 264.196( a), (b], Cc), and (d); and

(ii) Prevent the migration of hazardouswaste or hazardous constituents toground water or surface water, ifpossible, and decontaminate or removecontaminated soil. If contaminated soilcannot be decontaminated or removedor if ground water has beencontaminated, the owner or operatormust comply with the requirements of§ 264.197(b); and

(iii) If repairing, replacing, orreinstalling the tank system, providesecondary containment in accordancewith the requirements of paragraphs (a)through (f) of this section or reapply fora variance from secondary containmentand meet the requirements for new tanksystems in §- 264.192 if the tank system isreplaced. The owner or operator mustcomply with these requirements even ifcontaminated soil can bedecontaminated or removed and groundwater or surface water has not beencontaminated.

(h) The following procedures must befollowed in order to request a varfianefrom secondary containment:

(11 The Regional Administrator mustbe notified in writing by the owner oroperator that he intends to conduct andsubmit a demonstration for a variancefrom secondary containment as allowedin paragraph (g) according to thefollowing schedule:, (i) For-existing tank systems, at least

24 months prior to the date thatsecondary containment must beprovided in accordance with paragraph(a) of this section.

(iij For new tank systems, at least 30days prior to entering into a contract forinstallation.

(2) As part of the notification, theowner or operator must also submit tothe Regional Administrator a descriptionof the steps necessary to conduct thedemonstration and a timetable forcompleting each of the steps. Thedemonstration must address each of thefactors listed in paragraph (g)(11 orparagraph (g)(2) of this section;

(3) The demonstration for a variancemust be completed within 180 days afternotifying the Regional Administrator ofan intent to conduct the demonstration;and

(4) If a variance is granted under thisparagraph, the Regional Administratorwill require the permittee to constructand operate the tank system in themanner that was demonstrated to meetthe requirements for the variance.

[i) All tank systems, until such time assecondary containment that meets therequirements of this section is provided,must comply with the following-

(1) For non-enterable undergroundtanks, a leak test that meets therequirements of § 264.191(a) or othertank integrity method, as approved orrequired by the Regional Administrator,must be conducted at least annually.

(2) For other than non-enterableunderground tanks, the owner oroperator must either (i) conduct a leaktest as in paragraph (i)(1) or (it) of thissection develop a schedule andprocedure for an assessment of theoverall condition of the tank system byan independent, qualified registeredprofessional engineer. The schedule andprocedure must be adequate to detectobvious cracks, leaks, and corrosion orerosion that may lead to cracks andleaks. The owner or operator mustremove the stored waste from the tank.if necessary, to allow the condition of allinternal tank surfaces to be assessed.The frequency of these assessmentsmust be based on the material ofconstruction of the tank and its ancillaryequipment, the age of the system, thetype of corrosion or erosion protectionused, the rate of corrosion or erosionobserved during the previous inspection,and the characteristics of the wastebeing stored or treated.

(31 For ancillary equipment, a leak testor other integrity assessment asapproved by the Regional Administratormust be conducted at least annually.

lNote.-The practices described in theAmerican Petroleum Institute (API)Publication Guide for Inspection of Refinery.Equipment. Chapter XIIl, "Atmospheric andLow-Pressure Storage Tanks," 4th edition.1981, may be used, where appliceble as

guidelines for assessing the overall conditionof the tank system.]

(4) The owner or operator mustmaintain on file at the facility a recordof the results of the assessmentsconducted in accordance withparagraphs (i)(1) through (i)(3) of thissection.

(5 If a tank system or component isfound to be leaking or unfit for use as aresult of the leak test or assessment inparagraphs (i)(1) through (i]f3) of thissection, the owner or operator mustcomply with the requirements of§ 264.196.(Information collection requirementscontained in paragraphs (cl, (d), (el, [g), (h),and (i) were approved by the. Office ofManagement and Budget under controlnumber 2050-0050.)

§ 264.194 General operating requirements.(a) Hazardous wastes or treatment

reagents must not be placed in a tanksystem if they could cause the tank, itsancillary equipment, or the containmentsystem to rupture, leak, corrode, orotherwise fail.

(b) The owner or operator must useappropriate controls and practices toprevent spills and overflows from tankor containment systems. These includeat a minimum:(1) Spill prevention controls (e.g..

check valves, dry disconnect couplings);(2) Overfill prevention controls (e.g.,

level sensing devices, high level alarms.automatic feed cutoff, or bypass to astandby tank); and

(3) Maintenance of sufficientfreeboard in uncovered tanks to preventovertopping by wave or wind action orby precipitation.

Cc) The owner or operator mustcomply with the requirements of§ 264.196 if a leak or spill occurs in. thetank system.

(Information collection requirementscontained in paragraph Cc) were approved bythe Office of Management and Budget undercontrol number 2050-0050)

§264.195 Inspections.(a) The owner or operator must

develop and follow a schedule andprocedure for inspecting overfillcontrols.

(b) The owner or operator mustinspect at least once each operating day:

(1) Aboveground portions of the tanksystem, if any, to detect corrosion orreleases of waste;

(2) Data gathered from monitoring andleak detection equipment (e.g., pressureor temperature gauges, monitoringwells) to ensure that the tank system isbeing operated according to its design:and

25476




(3) The construction materials and thearea immediately surrounding theexternally accessible portion of the tanksystem, including the secondarycontainment system (e.g., dikes) todetect erosion or signs of releases ofhazardous waste (e.g., wet spots, deadvegetation).

[Note.-Section 264.15(c) requires theowner or operator to remedy anydeterioration or malfunction he finds. Section264.196 requires the owner or* operator tonotify the Regional Administrator within 24hours of confirming a leak. Also, 40 CFR Part302 may require the owner or operator tonotify the National Response Center of arelease.]

(c) The owner or operator mustinspect cathodic protection systems, ifpresent, according to, at a minimum, thefollowing schedule to ensure that theyare functioning properly:

(1) The proper operation of thecathodic protection system must beconfirmed within six months after initialinstallation and annually thereafter; and

(2] All sources of impressed currentmust be inspected and/or tested, asappropriate, at least bimonthly (i.e.,every other month).

[Note.-The practices described in theNational Association of Corrosion Engineers(NACE) standard, "Recommended Practice(RP-02-85)--Control of External Corrosion onMetallic Buried, Partially Buried, orSubmerged Liquid Storage Systems," and theAmerican Petroleum Institute (API)Publication 1632, "Cathodic Protection ofUnderground Petroleum Storage Tanks andPiping Systems," may be used, whereapplicable, as guidelines in maintaining andinspecting cathodic protection systems.]

(d) The owner or operator mustdocument in the operating record of thefacility an inspection of those items inparagraphs (a) through (c) of thissection.(Information collection requirementscontained in paragraph (a) and (d] wereapproved by the Office of Management andBudget under control number 2050-0050)

§ 264.196 Response to leaks or spills anddisposition of leaking or unfit-for-use tanksystems.

A tank system or secondarycontainment system from which therehas been a leak or spill, or which is unfitfor use, must be removed from serviceimmediately, and the owner or operatormust satisfy the following requirements:

(a) Cessation of Use; prevent flow oraddition of wastes. The owner oroperator must immediately stop the flowof hazardous waste into the tank systemor secondary containment system andinspect the system to determine thecause .of the release.

(b) Removal of waste from tanksystem or secondary containment

system. (1) If the release was from thetank system, the owner/operator must,within 24 hours after detection of theleak or, if the owner/operatordemonstrates that it is not possible, atthe earliest practicable time, remove asmuch of the waste as is necessary toprevent further release of hazardouswaste to the environment and to allowinspection and repair of the tank systemto be performed.

(2) If the material released was to asecondary containment system, allreleased materials must be removedwithin 24 hours or in as timely a manneras is possible to prevent harm to humanhealth and the environment.

(c) Containment of visible releases tothe environment. The owner/operatormust immediately conduct a visualinspection of the release and, basedupon that inspection:

(1) Prevent further migration of theleak or spill to soils or surface water;and

(2) Remove, and properly dispose of,any visible contamination of the soil orsurface water.

[d) Notifications, reports. (1) Anyrelease to the environment, except asprovided in paragraph (d)(2) of thissection, must be reported to theRegional Administrator within 24 hoursof its detection. If the release has beenreported pursuant to 40 CFR Part 302,that report will satisfy this requirement.

(2) A leak or spill of hazardous wastethat is:

(i] Less than or equal to a quantity ofone (1) pound and

(ii) Immediately contained andcleaned-up is exempted from therequirements of this paragraph.

(3) Within 30 days of detection of arelease to the environment, a reportcontaining the following informationmust be submitted to the RegionalAdministrator:

(i] Likely route of migration of therelease;

(ii) Characteristics of the surroundingsoil (soil composition, geology,hydrogeology, climate);

(iii) Results of any monitoring orsampling conducted in connection withthe release (if available). If sampling ormonitoring data relating to the releaseare not available within 30 days, thesedata must be submitted to the RegionalAdministrator as soon as they becomeavailable.

(iv) Proximity to downgradientdrinking water, surface water, andpopulation areas; and

(v) Description of response actionstaken or planned.

(e) Provision of secondarycontainment, repair, or closure. (1)Unless the owner/operator satisfies the

requirements of paragraphs (e)(2)through (4) of this section, the tanksystem must be closed in accordancewith § 264.197.

(2) If the cause of the release was aspill that has not damaged the integrityof the system, the owner/operator mayreturn the system to service as soon asthe released waste is removed andrepairs, if necessary, are made.

(3) If the cause of the release was aleak from the primary tank system intothe secondary containment system, thesystem must be repaired prior toreturning the tank system to service.

(4) If the source of the release was aleak to the environment from acomponent of a tank system withoutsecondary containment, the owner/operator must provide the component ofthe system from which the leak occurredwith secondary containment thatsatisfies the requirements of § 264.193before it can be returned to service,unless the source of the leak is anaboveground portion of a tank systemthat can be inspected visually. If thesource is an aboveground componentthat can be inspected visually, thecomponent must be repaired and may bereturned to service without secondarycontainment as long as the requirementsof paragraph (f) of this section aresatisfied. If a component is replaced tocomply with the requirements of thissubparagraph, that component mustsatisfy the requirements for new tanksystems or components in § § 264.192and 264.193. Additionally, if a leak hasoccurred in any portion of a tank systemcomponent that is not readily accessiblefor visual inspection (e.g., the bottom ofan inground or onground tank), theentire component must be provided withsecondary containment in accordancewith § 264.193 prior to being returned touse.

(f) Certification of major-repairs. Ifthe owner/operator has repaired a tanksystem in accordance with paragraph (e)of this section, and the repair has beenextensive [e.g., installation of an internalliner; repair of a ruptured primarycontainment or secondary containmentvessel), the tank system must not bereturned to service unless the owner/operator has obtained a certification byan independent, qualified, registered,professional engineer in accordancewith § 270.11(d) that the repaired systemis capable of handling hazardous wasteswithout release for the intended life ofthe system. This certification must besubmitted to the Regional Administratorwithin seven days after returning thetank system to use.

[Note.-The Regional Administrator may,on the-basis of any information received that

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. Federal Register / Vol. 51, No. 134 / Monday, July 14, 1986 / Rules and Regulations

there is or has been a release of hazardouswaste or hazardous constituents into theenvironmenL issue an order under RCRAsections 3004(w), 3008(h), or 7003[a) requiringcorrective action or such other response asdeemed necessary to protect human health orthe environment.1

[Note.-See § 264.15(c) for the requirementsnecessary to remedy a failure. Also, 40 CFRPart 30Z may require the owner or operator tonotify the National Response Center ofcertain releases.l

(information collection requirementscontained in paragraphs (d), (e). a-d (f) wereapproved by the Office of Management andBudget under control number 2050-00501

§ 264.197 Closure and post-closure care.(a) At closure of a tank system, the

owner or operator must remove ordecontaminate all waste residues,contaminated containment systemcomponents (liners, etc.), contaminatedsoils, and structures and equipmentcontaminated with waste, and managethem as hazardous waste, unless§ 261.3(d) of this Chapter applies. Theclosure plan, closure activities, costestimates for closure, and financialresponsibility for tank systems mustmeet all of the requirements specified inSubparts G and H of this Part.

(b) If the owner or operatordemonstrates that not all contaminatedsoils carn be, practicably removed ordecontaminated as required inparagraph (a) of this section, then theowner or operator must close the tanksystem and perform post-closure care inaccordance with the closure and post-closure care requirements that apply tolandfills (§ 264.3101. In addition, for thepurposes of closure, post-closure, andfinancial responsibility, such a tanksystem is then considered to be alandfill, and the owner or operator mustmeet all of the requirements for landfillsspecified in Subparts G and H of thisPart.

(c. If an owner or operator has a tanksystem that does not have secondarycontainment that meets therequirements of 1264.193 (b) through (f)and is not exempt from the secondarycontainment requirements in accordancewith §264.193(g), then:

(1) The closure plan for the tanksystem must include both a plan forcomplying with paragraph (a) of thissection and a contingent plan forcomplying with paragraph {l) of thissection..

(2) A contingent post-closure plan forcomplying with paragraph (b) of thissection must be prepared and submittedas part of the permit application.

(al The cost estimates calculated forclosure and post-closure care mustreflect the costs of complying with thecontingent closure plan and the

contingent post-closure plan, if thosecosts are greater than the costs ofcomplying with the closure planprepared for the expected closure underparagraph (a)r of this section.

(4) Financial assurance must be basedon the cost estimates in paragraph (cJ(3)of this section.

(5) For the parposes of the contingentclosure and post-closure plans, such atank system is considered to be alandfill, and the contingent plans mustmeet all of the closure, post-dosure, andfinancial responsibility requirements forlandfills under Subparts G and H of thisPart.

(Information collection requirementscontained in paragraphs (a)-c) wereapproved by the Office of Management andBudget under control number 2050-00501

§ 264.198 Special requirements forIgnitable or reactive wastes.

(a) Ignitable or reactive waste mustnot be placed in tank systems, unless:

(1) The waste is treated,. rendered, ormixed before or immediately afterplacement in the tank system so that:

(i) The resulting waste, mixture, ordissolved material no longer meets thedefinition of ignitable or reactive wasteunder § § 261.21 or 261.23 of this Chapter,and

(ii) Seytion 264.17(b) is complied with:or

(2) The waste is stored or treated insuch a way that it is protected from anymaterial or conditions that may causethe waste to ignite or react; or

(3) The tank system is used solely foremergencies.

(b) The owner or operator of a facilitywhere ignitable or reactive waste isstored or treated in a tank must complywith the requirements for themaintenance of protective distancesbetween the waste management areaand any public ways, streets, alleys, oran adjoining property line that can bebuilt upon as required in Tables 2-1through 2-6 of the National FireProtection Association's "Flammableand Combustible Liquids Code," (1977 or1981), (incorporated by reference, see§ 260. 1).

§ 264.199 Special requirements forincompatible wastes.

(a) Incompatible wastes, orincompatible wastes and materials,must not be placed in the same tanksystem, unless § 264.17(b) is compliedwith.

(b) Hazardous waste must not beplaced in a tank system that has notbeen decontaminated and thatpreviously held an incompatible wasteor material, unless § 264.17(b) iscomplied with.

PART 265-INTERIM STATUSSTANDARDS FOR OWNERS ANDOPERATORS OF HAZARDOUS WASTETREATMENT, STORAGE, ANDDISPOSAL FACILUTIES


14. The Authority citation for Part 265continues to read as follows:

Authority. Sees. 100& 2002(a),. 3004, 3005.and 30M5 of the Solid Waste Disposal Act asamended by the Resource Conservation andRecovery Act of 1976, as amended (42 U.S.C.6905, 6912(a), 6924i 6925, and 6935).

15. The Table of Contents and theheading of Part 265, Subpart J-Tanks isrevised to read as follows:


Sec.265.190 Applicability.265.191 Assessment of existing tank

system's integrity.265.192 Design and installation of new tank

systems or components.265.193 Containment and detection of

releases.265.194 General operating requirements.265.195 Inspections.265.196 Response to leaks or spils and

disposition of leaking or unfit-for-usetank systems.

265.197 Closure and post-closure care.265.198 Special requirements for ignitable or

reactive wastes.265.199 Special requirements for

incompatible wastes.265.200 Waste analysis and trial tests.265.201 Special requirements for generators

of between 100 and 1,000 kg/mo thataccumulate hazardous waste in tanks.


§ 265.13 General waste analysis.

(bT(6) Where applicable, the methods

that will be used to meet the additionalwaste analysis requirements for specificwaste management methods asspecified in § §: 265.200, 265.225,,265.252.265.273, 265.314, 265.345, 265.375, and265.402.


§ 265.15 General Inspection requirements.

(b) *(4) The frequency of inspection may

vary for the items on the schedule.However, it should be based on the rateof possible deterioration of the

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Federal Register / Vol. 51, No. 134 / Monday, July 14, 1986 / Rules and Regulations4

equipment and the probability of anenvironmental or human health incidentif the deterioration, or malfunction, orany operator error goes undetectedbetween inspections. Areas subject tospills, such as loading and unloadingareas, must be inspected daily when inuse. At a minimum, the inspectionschedule must include the items andfrequencies called for in §§ 265.174,265.193, 265.195, 265.226, 265.347, 265.377,and 265.403.

18. Section 265.73 is amended byrevising paragraphs (b)(3) and (b)(6) toread as follows:

§ 265.73 Operating record.

(b) * *(3) Records and results of waste

analysis and trial tests performed asspecified in § § 265.13, 265.200, 265.225,265.252, 265.273, 265.314, 265.341, 265.375,and 265.402.

(6) Monitoring, testing, or analyticaldata when required by § § 265.90, 265.94,265.191, 265.193, 265.195, 265.276, 265.278,265.280(d)(1), 265.347. and 265.377; and


§ 265.110 Applicability.{b * * *

(b)**(2) Tank systems that are required

under § 265.197 to meet requirements forlandfills.

20. Section 265.140 is amended byrevising paragraph (b) to read asfollows:


(b) The requirements of § § 265.144and 265.146 apply only to owners andoperators of disposal facilities and tanksystems that are required under§ 265.197 to meet the requirements forlandfills

21. The Subpart I is revised to read as

follows:


§ 265.190 Applicability.The regulations of this Subpart apply

to owners or operators of facilities thatuse tank systems for storing or treatinghazardous waste, except as otherwiseprovided in paragraphs (a) and (b) ofthis section or in § 265.1 of this part.

(a) Tanks that are used to store ortreat hazardous waste containing no

free liquids and that are situated insidea building with an impermeable floorare exempted from the requirements of§ 265.193 of this subpart. Todemonstrate the absence or presence offree liquids in the stored/treated waste,EPA Method 9095 (Paint Filter LiquidsTest) as described in "Test Methods forEvaluating Solid Wastes, Physical/Chemical Methods" (EPA PublicationNo. SW-846) must be used.

(b) Tanks, including sumps, as definedin § 260.10, that serve as part of asecondary containment system to collector contain releases of hazardous wastesare exempted from the requirements in§ 265.193.(Information collection requirementcontained in paragraph (a) was approved bythe Office of Management and Budget undercontrol number 2050-0050.)

§ 265.191 Assessment of existing tanksystem's Integrity.

(a) For each. existing tank system thatdoes not have secondary containmentmeeting the requirements of § 265.193,the owner or operator must determinethat the tank system is not leaking or isunfit for use. Except as provided inparagraph (c) of this section, the owneror operator must obtain and keep on fileat the facility a written assessmentreviewed and certified by anindependent, qualified, registeredprofessional engineer in accordancewith § 270.11(d), that attests to the tanksystem's integrity by January 12, 1988.

(b) This assessment must determinethat the tank system is adequatelydesigned and has sufficient structuralstrength and compatibility with thewaste(s) to be stored or treated toensure that it will not collapse, rupture,or fail. At a minimum, this assessmentmust consider the following:

(1) Design standard(s), if available,according to which the tank andancillary equipment were constructed;

(2) Hazardous characteristics of thewaste(s) that have been or will behandled;

(3) Existing corrosion protectionmeasures;

(4) Documented age of the tanksystem, if available, (otherwise, anestimate of the age); and

(5) Results of a leak test, internalinspection, or other tank integrityexamination such that:

(i) For non-enterable undergroundtanks, this assessment must consist of aleak test that is capable of taking intoaccount the effects of temperaturevariations, tank end deflection, vaporpockets, and high water table effects,

(ii) For other than non-enterableunderground. tanks and for ancillaryequipment, this assessment must be

either a leak test, as described above, oran internal inspection and/or other tankintegrity examination certified by anindependent, qualified, registeredprofessional engineer in accordancewith § 270.11(d) that addresses cracks,leaks, corrosion, and erosion'.

[Note.-The practices described in theAmerican Petroleum Institute (API]Publication. Guide for Inspection of RefineryEquipment, Chapter XIII. "Atmospheric andLow-Pressure Storage Tanks," 4th edition,1981, may be used, where applicable, asguidelines in conducting the integrityexamination of an other than inn-enterdbieunderground tank system)

(c) Tank systems that store or treatmaterials that become hazardous wastessubsequent to July 14, 1986 must conductthis assessment within 12 months afterthe date that the waste becomes ahazardous waste.

(d) If, as a result of the assessmentconducted in accordance withparagraph (a) of this section, a tanksystem is found to be leaking or unfit foruse, the owner or operator must complywith the requirements of § 265.196.

(Information collection requirementscontained in paragraphs (aHd wereapproved by the Office of Management andBudget under control number 2050-0050.

§ 265.192 Design and Installation of newtank systems or components.

(a) Owners or operators of new tanksystems, or components must ensure tkatthe foundation, structural support,seams, connections, and pressurecontrols (if applicable) are adequatelydesigned and that the tank system hassufficient structural strength.compatibility with the waste(s) to bestored or treated, and corrosionprotection so that it will not collapse,rupture, or fail. The owner or operatormust obtain a written assessmentreviewed and certified by anindependent, qualified, registeredprofessional engineer in accordancewith § 270.11(df attesting that thesystem has sufficient structural integrityand is acceptable for the storing andtreating of hazardous waste. Thisassessment must include, at a minimum,the following information:

(1) Design standard(s) according towhich the tank(s) and ancillaryequipment is or will be constructed.

(2) Hazardous characteristics of thewaste(s) to be handled.

(3) For new tank systems orcomponents in which the external shellof a metal tank or any external metal.component of the tank system is or willbe in contact with the soil or with water,a determination by a corrosion expertof:

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25480 Federal Register / Vol. 51, No. 134 / Monday, July 14, 1986 / Rules and Regulations

(i) Factors affecting the potential forcorrosion, including but not limited to:

(A) Soil moisture content;(B) Soit pH;(C) Soil sulfides level;(D) Soil resistivity;(E) Structure to soil potential;(F) Influence of nearby underground

metal structures (e.g., piping);(G) Stray electric current;(H) Existing corrosion-protection

measures (e.g., coating, cathodicprotection), and

(ii) The type and degree of externalcorrosion protection that are needed toensure the integrity of the tank systemduring the use of the tank system orcomponent, consisting of one or more ofthe following:

(A) Corrosion-resistant materials ofconstruction such as special alloys,fiberglass-reinforced plastic, etc.;

(B) Corrosion-resistant coating (suchas epoxy, fiberglass, etc.) with cathodicprotection (e.g., impressed current orsacrificial anodes); and

(C) Electrical isolation devices such asinsulating joints, flanges, etc.

[Note.-The practices described in theNational Association of Corrosion Engineers(NACE) standard, "Recommended Practice(RP-02-85)-Control of External Corrosion onMetallic Buried, Partially Buried, orSubmerged Liquid Storage Systems," and theAmerican Petroleum Institute (API)Publication 1632. "Cathodic Protection ofUnderground Petroleum Storage Tanks andPiping Systems," may be used, whereapplicable, as guidelines in providingcorrosion protection for tank systems.]

(4) For underground tank systemcomponents that are likely to beaffected by vehicular traffic, adetermination of design or operationalmeasures that will protect the tanksystem against potential damage; and

(5) Design considerations to ensurethat:

(i) Tank foundations will maintain theload of a full tank;

(ii) Tank systems will be anchored toprevent flotation or dislodgement wherethe tank system is placed in a saturatedzone, or is located within a seismic faultzone; and

(iii) Tank systems will withstand theeffects of frost heave.

(b) The owner or operator of a newtank system must ensure that properhandling procedures are adhered to inorder to prevent damage to the systemduring installation. Prior to covering,enclosing, or placing a new tank systemor component in use, an independent,qualified installation inspector or anindependent, qualified, registeredprofessional engineer, either of whom istrained and experienced in the properinstallation of tank systems, must

inspect the system or component for thepresence of any of the following items:

(1) Weld breaks;(2) Punctures;(3) Scrapes of protective coatings;(4) Cracks;(5) Corrosion;(6) Other structural damage or

inadequate construction or installation.All discrepancies must be remediedbefore the tank system is covered,enclosed, or placed in use.

(c) New tank systems or componentsand piping that are placed undergroundand that are backfilled must be providedwith a backfill material that is anoncorrosive, porous, homogeneoussubstance and that is carefully installedso that the backfill is placed completelyaround the tank and compacted toensure that the tank and piping are fullyand uniformly supported.

(d) All new tanks and ancillaryequipment must be tested for tightnessprior to being covered, enclosed orplaced in use. If a tank system is foundnot to be tight, all repairs necessary toremedy the leak(s) in the system mustbe performed prior to the tank systembeing covered, enclosed, or placed in-use.

(e) Ancillary equipment must besupported and protected againstphysical damage and excessive stressdue to settlement, vibration, expansionor contraction.

[Note.-The piping system installationprocedures described in American PetroleumInstitute (API) Publication 1615 (November1979), "Installation of Underground PetroleumStorage Systems," or ANSI Standard B31.3,"Petroleum Refinery System," may be used,where applicable, as guidelines for properinstallation of piping systems.]

(f0 The owner or operator mustprovide the type and degree of corrosionprotection necessary, based on theinformation provided under paragraph(a)(3) of this section, to ensure theintegrity of the tank system during useof the tank system. The installation of acorrosion protection system that is fieldfabricated must be supervised by anindependent corrosion expert to ensureproper installation.

(g) The owner or operator must obtainand keep on file at the facility writtenstatements by those persons required tocertify the design of the tank system andsupervise the installation of the tanksystem in accordance with therequirements of paragraphs (b) through(f) of this section to attest that the tanksystem was properly designed andinstalled and that repairs, pursuant toparagraphs (b) and (d) of this sectionwere performed. These writtenstatements must also include the

certification statement as required in§ 270.11(d) of this chapter.(Information collection requirementscontained in paragraphs (a) and (g) wereapproved by the Office of Management andBudget under control number 2050-0050.)

§ 265.193 Containment and detection ofreleases.

(a) In order to prevent the release ofhazardous waste or hazardousconstituents to the environment,secondary containment that meets therequirements of this section must beprovided (except as provided inparagraphs (f) and (g) of this section):

(1) For all new tank systems orcomponents, prior to their being put intoservice;

(2) For all existing tanks used to storeor treat EPA Hazardous Waste Nos.F020, F021, F022, F023, F026, and F027,within two years after January 12, 1987;

(3) For those existing tank systems ofknown and documentable age, withintwo years after January 12, 1987, orwhen the tank systems have reached 15years of age, whichever comes later;

(4) For those existing tank system forwhich the age cannot be documented,within eight years of January 12, 1987;but if the age of the facility age isgreater than seven years, secondarycontainment must be provided by thetime the facility reaches 15 years of age,or within two years of January 12, 1987,whichever comes later; and

(5) For tank systems that store or treatmaterials that become hazardous wastessubsequent to January 12, 1987, withinthe time intervals required inparagraphs (a)(1) through (a)(4) of thissection, except that the date that amaterial becomes a hazardous wastemust be used in place of January 12,1987.

(b) Secondary containment systemsmust be:

(1) Designed, installed, and operatedto prevent any migration of wastes oraccumulated liquid out of the system tothe soil, ground water, or surface waterat any time during the use of the tanksystem; and

(2) Capable of detecting and collectingreleases and accumulated liquids untilthe collected material is removed.

(c) To meet the requirements ofparagraph (b) of this section, secondarycontainment systems must be at aminimum:

(1) Constructed of or lined withmaterials that are compatible with thewaste(s) to be placed in the tank systemand must have sufficient strength andthickness to prevent failure due topressure gradients (including static headand external hydrological forces),




physical contact with the waste towhich they are exposed, climatic.conditions, the stress of installation, andthe stress of daily operation (includingstresses from nearby vehicular traffic)-

(2) Placed on a foundation or basecapable of providing support to thesecondary containment system andresistance to pressure gradients aboveand below the system and capable ofpreventing failure due to settlement.compression, or uplift:

(3) Provided with- a leak detection.system that is designed and operated sothat it will detect the failure of either theprimary and secondary containmentstructure or any release of hazardouswaste or accumulated liquid in thesecondary containment system within 24hours, or at the earliest practicable timeif the existing detection technology orsite conditions will not allow detectionof a release within 24 hours;

(4) Sloped or otherwise designed oroperated to drain and. remove liquidsresulting from leaks, spills, orprecipitation. Spilled or leaked wasteand accumulated precipitation must beremoved from the secondarycontainment system within 24 hours, orin as timely a manner as is possible toprevent harm to human health or theenvironment, if removal of the releasedwaste or accumulated precipitationcannot be accomplished within 24 hours.

lNote.-lf the collected material is ahazardous waste under Part 261 of thischapter, it is subject to management as ahazardous waste in accordance with allapplicable requirements of Parts 262 throughm5 of this chapter If the collected material isdischarged through. a point source to waters.of the United States. it is subject to therequirements of sections 301, 304,, and 402 ofthe Clean Water Act, as amended. Ifdischarged to Publicly Owned TreatmentWorks [POTWs], it is subject to therequirements of section 307 of the ClearWater Act, as amended. If the collectedmaterial is released to the environment, itmay be subject to the reporting requirementsof 40 CFR Part 302.1

(d) Secondary containment for tanksmust include one or more of thefollowing devices:

(1) A liner (external to the tank)(2) A vault,(3) A double-walled tank; or(4) An equivalent device as approved

by the Regional Administrator.(e) In addition to the requirements of

paragraphs (b), (c), and (d) of thissection, secondary containment systemsmust satisfy the followving requirements-

(1) External liner systems must be:(i) Designed or operated to contain 100

percent of the capacity of the largesttank within its boundary-

(ii) Designed or operated to preventrun-on or infiltration of precipitation

into the secondary containment systemunless the collection system hassufficient excess capacity to, containrun-on or infiltration. Such additionalcapacity must be sufficient to containprecipitation from a 25-year, 24-hourrainfall event;

(iii) Free of cracks or gaps; and(iv) Designed and installed to

completely surround the tank and tocover all surrounding, earth likely tocome into contact with the waste ifreleased from the tank(s) (i.e, capableof preventing lateral as well. as verticalmigration of the waste).

(2) Vault systems must be:(il Designed or operated to contain 100

percent of the capacity of the largesttank within its boundary:

(ii) Designed or operated to preventrun-on or infiltration of precipitationinto the secondary containment systemunless the collection system hassufficient to contain run-on orinfiltration. Such additional capacitymust be sufficient to. containprecipitation from a 25-year, 24-hourrainfall event;

(iii) Constructed with chemical-resistant water stops in place at alljoints (if any);

(iv) Provided with an impermeableinterior coating, or lining that iscompatible; with the stored waste andthat will prevent migration of waste intothe concrete;

(v} Provided with a means' to protectagainst the formation of and ignition ofvapors within the vault, if the wastebeing stored or treated:

(AY Meets the definition, of ignitablewaste under § 262.21 of this chapter, or

(B) Meets the definition of reactivewaste under § 262.21 of this chapter andmay form an ignitable or explosivevapor; and

(vi) Provided with an exteriormoisture barrier or be otherwisedesigned or operated to preventmigration of moisture into the vault ifthe vault is subject to hydraulicpressure.

(3) Double-walled tanks must be:(i) Designed as an integral structure

(i.e., an inner tank within an outer shell)so that any release from the inner tankis contained by the outer shell;

(ii) Protected, if constructed of metal,from both, corrosion of the primary tankinterior and the external surface of theouter shell; and

(iii) Provided with a built-in,continuous leak detection systemcapable of detecting a release within 24hours or at the earliest practicable time,if the owner or operator candemonstrate to the RegionalAdministrator, and the RegionalAdministrator concurs, that the existing

leak detection, technology or siteconditions will not allow detection of arelease within 24 hours.

[Note. -The provisions outlined in theSteel Tank institute's (STI) '.Standard forDual Wall Underground Steel Storage Tank"may be used as guidelines for aspects of thedesign of underground steel double-walledtanks.I

(0,) Ancillary equipment must beprovided with full secondarycontainment (e.g.. trench, jacketing,double-walled piping) that meets therequirements of paragraphs (b) and c}Jof this section except for:

(1) Aboveground piping (exclusive offlanges, joints, valves, and connections)that are visually inspected for leaks on, adaily basis;

(2) Welded flanges, welded joints, andwelded connections that are visuallyinspected for leaks on a daily basis;,

(3) Sealless or magnetic couplingpumps that are visually inspected forleaks on a daily basis; and

(4) Pressurized aboveground pipingsystems with automatic shut-off devices(e.g., excess flow check valves, flowmetering shutdown devices, loss ofpressure actuated shut-off devices) thatare visually inspected for leaks on adaily basis.

(g) The owner or operator may obtaina variance from the requirements of thisSection if the Regional Administratorfinds, as a result of a demonstration bythe owner or operator, either

(1) That alternative design andoperating practices, together withlocation characteristics, will prevent themigration of hazardous waste orhazardous constituents into the groundwater or surface water at least aseffectively as secondary containmentduring the active life of the tank systemor (2) that in the event of a release thatdoes migrate to ground water or surfacewater, no substantial present orpotential hazard will be posed to humanhealth. or the environment. Newunderground tank systems may not. pera demonstration in accordance withparagraph (g)(2) of this section, beexempted from the secondarycontainment requirements of thissection. Application for a variance asallowed in paragraph (g) of this sectiondoes not waive compliance with therequirements of this Subpart for newtank systems.

(1) In deciding whether to grant avariance based on a demonstration ofequivalent protection of ground waterand surface water, the RegionalAdministrator will consider.

(i) The nature and quantity of thewaste;

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25482 Federal Register / Vol. 51, No. 134 / Monday, July 14, 1986 / Rules and Regulations

(ii) The proposed alternate design andoperation;

(iii) The hydrogeologic setting of thefacility, including the thickness of soilsbetween the tank system and groundwater;, and

(iv) All other factors that wouldinfluence the quality and mobility of thehazardous constituents and the potentialfor them to migrate to ground water orsurface water.

(2) In deciding whether to grant avariance, based on a demonstration ofno substantial present or potentialhazard, the Regional Administrator willconsider:

(i) The potential adverse effects onground water, surface water, and landquality taking into account:

(A) The physical and chemicalcharacteristics of the waste in the tanksystem, including its potential formigration,

(B) The hydrogeologicalcharacteristics of the facility andsurrounding land,

(C) The potential for health riskscaused by human exposure to wasteconstituents,

(D) The potential for damage towildlife, crops, vegetation, and physicalstructures caused by exposure to wasteconstituents, and

(E) The persistence and permanenceof the potential adverse effects;

(ii) The potential adverse effects of arelease on ground-water quality, takinginto account:


(B) The proximity and withdrawalrates of water in the area,

(C) The current and future uses ofground water in the area, and

(D) The existing quality of groundwater, including other sources ofcontamination and their cumulativeimpact on the ground-water quality;

(iii) The potential adverse effects of arelease on surface water quality, takinginto account:


(B) The patterns of rainfall in theregion,

(C) The proximity of the tank systemto surface waters,

(D) The current and future uses ofsurface waters in the area and anywater quality standards established forthose surface waters, and

(E) The existing quality of surfacewater, including othersources ofcontamination and the cumulative.impact on surface-water quality; and

(iv) The potential adverse effects of arelease on the land surrounding the tanksystem, taking into account:

(A) The patterns of rainfall in theregion, and

(B) The current and future uses of thesurrounding land.

(3) The owner or operator of a tanksystem, for which a variance fromsecondary containment had beengranted in accordance with therequirements of paragraph (g](1) of thissection, at which a release of hazardouswaste has occurred from the primarytank system but has not migratedbeyond the zone of engineering control(as established in the variance), must:

(i) Comply with the requirements of§ 265.196, except paragraph (d); and

(ii) Decontaminate or removecontaminated soil to the extentnecessary to:

(A) Enable the tank system, for whichthe variance was granted, to resumeoperation with the capability for thedetection of and response to releases atleast equivalent to the capability it hadprior to the release, and

(B) Prevent the migration of hazardouswaste or hazardous constituents toground water or surface water; and

(iii) If contaminated soil cannot beremoved or decontaminated inaccordance with paragraph (g)(3)(ii) ofthis section, comply with therequirements of § 264.197(b);

(4) The owner or operator of a tanksystem, for which a variance fromsecondary containment had beengranted in accordance with therequirements of paragraph (g)(1) of thissection, at which a release of hazardouswaste has occurred from the primarytank system and has migrated beyondthe zone of engineering control (asestablished in the variance), must:

(i) Comply with the requirements of§ 265,196(a), (b), (c), and (d); and

(ii) Prevent the migration of hazardouswaste or hazardous constituents toground water or-surface water, ifpossible, and decontaminate or removecontaminated soil. If contaminated soilcannot be decontaminated or removed,or if ground water has beencontaminated, the owner or operatormust comply with the requirements of§ 265.197(b);

(iii) If repairing, replacing, orreinstalling the tank system, providesecondary containment in accordancewith the requirements of paragraphs (a)through (f) of this section or reapply fora variance'from secondary containmentand meet the requirements for new tanksystems in § 265.192 if the tank system isreplaced. The owner or operator mustcomply with these requirements even ifcontaminated soil can be

decontaminated or removed, and groundwater or surface water has not beencontaminated.

(h) The following procedures must befollowed in order to request a variancefrom secondary containment:

(1) The Regional Administrator mustbe notified in writing by the owner oroperator that he intends to conduct andsubmit a demonstration for a variancefrom secondary containment as allowedin paragraph (g) of this sectiqnaccording to the following schedule:

(i) For existing tank systems, at least24 months prior to the date thatsecondary containment must beprovided in accordance with paragraph(a) of this section; and

(ii) For new tank systems, at least 30days prior to entering into a contract forinstallation of the tank system.

(2) As part of the notification, theowner or operator must also submit tothe Regional Administrator a descriptionof the steps necessary to conduct thedemonstration and a timetable forcompleting each of the steps. Thedemonstration must address each of thefactors listed in paragraph (g)(1) orparagraph (g](2) of this section.

(3) The demonstration for a variancemust be completed and submitted to theRegional Administrator within 180 daysafter notifying the RegionalAdministrator of intent to conduct thedemonstration.

(4) The Regional Administrator willinform the public, through a newspapernotice, of the availability of thedemonstration for a variance. The noticeshall be placed in a daily or weeklymajor local newspaper of generalcirculation and shall provide at least 30days from the date of the notice for thepublic to review and comment on thedemonstration for a variance. TheRegional Administrator also will hold apublic hearing, in response to a requestor at his own discretion, whenever sucha hearing might clarify one or moreissues concerning the demonstration fora variance. Public notice of the hearingwill be given at least 30 days prior to thedate of the hearing and may be given atthe same time as notice of theopportunity for the public to review andcomment on the demonstration. Thesetwo notices may be combined.

(5) The Regional Administrator willapprove or disapprove the request for avariance within 90 days of receipt of thedemonstration from the owner oroperator and will notify in writing theowner or operator and each person whosubmitted written comments orrequested notice of the variancedecision. If the demonstration for avariance is incomplete or does not




include sufficient information, the 90-day time period will begin when theRegional Administrator receives acomplete demonstration, including allinformati on necessary to make a finaldetermination. If the public commentperiod in paragraph (h)(4) of this sectionis extended, the 90-day time period willbe similarly extended.

(i) All tank systems, until such time assecondary containment meeting therequirements of this section is provided.must comply with the following:

(1) For non-enterable undergroundtanks, a leak test that meets therequirements of § 265.191(a) must beconducted at least annually;

(2) For other than non-enterableunderground tanks and for all ancillaryequipment, an annual leak test, asdescribed in paragraph (i)(1) of thissection, or an internal inspection orother tank integrity examination by anindependent, qualified, registeredprofessional engineer that addressescracks, leaks, corrosion, and erosionmust be conducted at least annually.The owner or operator must remove thestored waste from the tank, if necessary,to allow the condition of all internaltank surfaces to be assessed.

[Note.-The practices described in theAmerican Petroleum Institute (API)Publication Guide for Inspection of RefiningEquipment, Chapter XIII. "Atmospheric andLow Pressure Storage Tanks," 4th edition.1981, may be used, when applicable, asguidelines for assessing the overall conditionof the tank system.]

(3) The owner or operator mustmaintain on file at.the facility a recordof the results of the assessmentsconducted in accordance withparagraphs (i)(1) through (i)(3) of thissection.

(4) If a tank system or component isfound to be leaking or unfit-for-use as aresult of the leak test or assessment inparagraphs (i)(1) through (i)(3) of thissection, the owner or operator mustcomply with the requirements of§ 265.196.(Information collection requirementscontained in paragraphs (c)-(e) and (g)-(i)were approved by the Office of Managementand Budget under control number 2050-0050.)

§265.194 General operating requirements.(a) Hazardous wastes or treatment

reagents must not be placed in a tanksystem if they could cause the tank, itsancillary equipment, or the secondarycontainment system to rupture, leak.corrode, or otherwise fail.

(b) The owner or operator must useappropriate controls and practices toprevent spills and overflows from tankor secondary containment systems.These include at a minimum:

(1) Spill prevention controls (e.g,check valves, dry discount couplings):

(2) Overfill prevention controls (e.g,level sensing devices, high level alarms,automatic feed cutoff, or bypass to astandby tank); and

(3) Maintenance of sufficientfreeboard in uncovered tanks to preventovertopping by wave or wind action orby precipitation.

(c) The owner or operator mustcomply with the requirements of§ 265.195 if a leak-or spill occurs in thetank system.(Information collection requirementscontained in paragraphs (c) were approvedby the Office of Management and Budgetunder control number 2050--0050.)

§ 265.195 Inspections.(a) The owner or operator must

inspect, where present, at least onceeach operating day:

(1) Overfill/spill control equipment(e.g.. waste-feed cutoff systems, bypasssystems, and drainage systems) toensure that it is in good working order;

(2) The aboveground portions of thetank system, if any, to detect corrosionor releases of waste;

(3) Data gathered from monitoringequipment and leak-detectionequipment, (e.g., pressure andtemperature gauges, monitoring wells) toensure that the tank system is beingoperated according to its design; and

(4) The construction materials and thearea immediately surrounding theexternally accessible portion of the tanksystem including secondary containmentstructures (e.g., dikes) to detect erosionor signs of releases of hazardous waste(e.g., wet spots, dead vegetation);

[Note.-Section 265.15(c) requires theowner or operator to remedy anydeterioration or malfunction he finds. Section265.196 requires the owner or operator tonotify the Regional Administrator within 24hours of confirming a release. Also, 40 CFRPart 302 may require the owner or operator tonotify the National Response Center of arelease.]

(b) The owner or operator mustinspect cathodic protection systems, ifpresent, according to, at a minimum, thefollowing schedule to ensure that theyare functioning properly:

(1) The proper operation of thecathodic protection system must beconfirmed within six months after initialinstallation, and annually thereafter;and

(2) All sources of impressed currentmust be inspected and/or tested, asappropriate, at least bimonthly (i.e.,every other month).

[Note.-The practices described in theNational Association of Corrosion Engineers(NACE] standard, "Recommended Practice

(RP--02-85)-Control of External Corrosion onMetallic Buried, Partially Buried, orSubmerged Liquid Storage Systems," and theAmerican Petroleum Institute (API)Publication 1632, "Cathodic Protection ofUnderground Petroleum Storage Tanks andPiping Systems," may be used, whereapplicable, as guidelines in maintaining andinspecting cathodic protection systems.]

(c) The owner or operator mustdocument in the operating record of thefacility an inspection of those items inparagraphs (a) and (b) of this section.(Information collection requirementscontained in paragraphs (a)-(c) wereapproved by the Office of Management andBudget under control number 2050-0050.)

§ 265.196 Response to leaks or spills anddisposition of leaking or unfit-for-use tanksystems.

A tank system or secohdarycontainment system from which therehas been a leak or spill, or which is unfitfor use, must be removed from serviceimmediately, and the owner or operatormust satisfy the following requirements:

(a) Cessation of use: prevent flow oraddition of wastes. The owner oroperator must immediately stop the flowof hazardous waste into the tank systemor secondary containment system andinspect the system to determine thecause of the release.

(b) Removal of waste from tanksystem or secondary containmentsystem. (1) If the release was from thetank system, the owner or operatormust, within 24 hours after detection ofthe leak or, if the owner or operatordemonstrates that that is not possible, atthe earliest practicable time remove asmuch of the waste as is necessary toprevent further release of hazardouswaste to the environment and to allowinspection and repair of the tank systemto be performed.

(2) If the release was to a secondarycontainment system, all releasedmaterials must be removed within 24hours or in as timely a manner as ispossible to prevent harm to humanhealth and the environment.

(c) Containment of visible releases tothe environment. The owner or operatormust immediately conduct a visualinspection of the release and, basedupon that inspection:

(1) Prevent further migration of theleak or spill to soils or surface water;and

(2) Remove, and properly dispose of,any visible contamination of the soil orsurface water.

(d) Notifications, reports. (1) Anyrelease to the environment, except asprovided in paragraph (d)(2) of thissection, must be reported to theRegional Administrator within.24 hours

41:Z1tr.qg., "JtU| P

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Federal Register / Vol. 51, No. 134 / Monday, July 14, 1986 1 Rules and Regulations

of detection. If the release has beenreported pursuant to 40 CFR Part 302,that report will satisfy this requirement.

(2) A leak or spill of hazardous wastethat is:

(i) Less than orequal to a quantity ofone (1) pound, and

(ii) Immediately contained andcleaned-up is exempted from therequirements of this paragraph.

(3) Within 30 days of detection of arelease to the environment, a reportcontaining the following informationmust be submitted to the RegionalAdministrator:

(i) Likely route of migration of therelease;

(ii) Characteristics of the surroundingsoil (soil composition, geology,hydrogeology, climate);

(iii) Results of any monitoring orsampling conducted in connection withthe release, (if available). If sampling ormonitoring data relating to the releaseare not available within 30 days, thesedata must be submitted to the RegionalAdministrator as soon as they becomeavailable.;

(iv) Proximity to downgradientdrinking water, surface water, andpopulation areas; and

(v) Description of response actionstaken or planned.

(e) Provision of secondarycontainment, repair, or closure. (1)Unless the owner or operator satisfiesthe requirements of paragraphs (e) (2)through (4) of this section, the tanksystem must be closed in accordancewith § 265.197.

(2) If the cause of the release was aspill that has not damaged the integrityof the system, the owner/operator mayreturn the system to service as soon asthe released waste is removed andrepairs, if necessary, are made.

(3).If the cause of the release was aleak from the primary tank system intothe secondary containment system, thesystem must be repaired prior toreturningthe tank system to service.

(4) If the source of the release was aleak to the environment from acomponent of a tank system withoutsecondary containment, the owner/operator must provide the component ofthe system from which the leak occurredwith secondary containment thatsatisfies the requirements of § 265.193before it can be returned to service,unless the source of the leak is anaboveground portion of a tank system. Ifthe source is an abovegroundcomponent that can be inspectedvisually, the component must berepaired and may be returned to servicewithout secondary containment as longas the requirements of paragraph (f) ofthis section are satisfied. If a component

is replaced to comply with therequirements of this subparagraph, thatcomponent must satisfy therequirements for new tank systems orcomponents in § § 265.192 and 265.193.Additionally, if a leak has occurred inany portion of a tank system componentthat is not readily accessible for visualinspection (e.g., the bottom of aninground or onground tank), the entirecomponent must be provided withsecondary containment in accordancewith § 265.193 prior to'being returned touse.

(f) Certification of major repairs. Ifthe owner or operator has repaired atank system in accordance withparagraph (e) of this section, and therepair has been extensive (e.g.,installation of an internal liner; repair ofa ruptured primary containment orsecondary containment vessel), the tanksystem must not be returned to serviceunless the owner/operator has obtaineda certification by an independent,qualified, registered professionalengineer in accordance with § 270.11(d)that the repaired system is capable ofhandling hazardous wastes withoutrelease for the intended life of thesystem. This certification must besubmitted to the Regional Administratorwithin seven days after returning thetank system to use.

[Note.-The Regional Administrator may,on the basis of any information received thatthere is or has been a release of hazardouswaste or hazardous constituents into theenvironment, issue an order under RCRAsections 3004(w), 3008(h), or 7003(a) requiringcorrective action or such other response asdeemed necessary to protect human health orthe environment.)

[Note.-See § 265.15(c) for the requirementsnecessary to remedy a failure. Also, 40 CFRPart 302 requires the owner or operator tonotify the National Response Center of arelease of any "reportable quantity."](Information collection requirementscontained in paragraphs (d)-(f) wereapproved by the Office of Management andBudget under control number 2050-0050.)

§ 265.197 Closure and post-closure care.(a) At closure of a tank system, the

owner or operator must remove ordecontaminate all waste residues,contaminated containment systemcomponents (liners, etc.), contaminatedsoils, and structures and equipmentcontaminated with waste, and managethem as hazardous waste, unless§ 261.3(d) of this Chapter applies. Theclosure plan, closure activities, costestimates for closure, and financialresponsibility for tank systems mustmeet all of the requirements specified inSubparts G and H of this Part.

(b) If the owner or operatordemonstrates that not all contaminated

soils can be -practicably removed ordecontaminated as required inparagraph (a) of this section, then theowner or operator must close the tanksystem and perform post-closure care inaccordance with the closure and post-closure care requirements that apply tolandfills (§ 265.310) In addition, for thepurposes of closure, post-closure, andfinancial responsibility, such a tanksystem is then considered to be alandfill, and the owner or operator mustmeet all of the requirements for landfillsspecified in Subparts G and H of thisPart.

(c) If an owner or operator has a tanksystem which does not have secondarycontainment that meets therequirements of § 265.193(b) through (f0and which is not exempt from thesecondary containment requirements inaccordance with § 265.193(g), then,

(1) The closure plan for the tanksystem must include both a plan forcomplying with paragraph (a) of thissection and a contingent plan forcomplying with paragraph (b] of thissection.

(2) A contingent post-closure plan forcomplying with paragraph (b) of thissection must be prepared and submittedas part of the permit application.

(3) The cost estimates calculated forclosure and post-closure care mustreflect the costs of complying with thecontingent closure plan and thecontingent post-closure plan, if thesecosts are greater than the costs ofcomplying with the closure planprepared for the expected closure underparagraph (a) of this section.

(4) Financial assurance must be basedon the cost estimates inparagraph (c](3)of this section.

(5) For the purposes of the contingentclosure and post-closure plans, such atank system is considered to be alandfill, and the contingent plans mustmeet all of the closure, post-closure, andfinancial responsibility requirements forlandfills under Subparts G and H of thisPart.(Information collection requirementscontained in paragraphs (a)-(c) wereapproved by the Office of Management andBudget under control number 2050-0050.)§ 265.198 Special requirements forIgnitable or reactive wastes.

(a) Ignitable or reactive waste mustnot be placed in a tank system, unless:

(1) The waste is treated, rendered, ormixedbefore or immediately afterplacement in the tank system so that:

(i) The resulting waste, mixture, ordissolved material no longer meets thedefinition of ignitable or reactive waste

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under §§ 261.21 or 261.23 of this Chapter;and

(ii) Section 265.17(b) is complied with:or

(2) The waste is stored or treated insuch a way that it is protected from anymaterial or conditions that may causethe waste to ignite or react; or

(3) The tank system is used solely foremergencies.

(b) The owner or operator of a facilitywhere ignitable or reactive waste isstored or treated in tanks must complywith the requirements for themaintenance of protective distancesbetween the waste management areaand any public ways, streets, alleys, oran adjoining property line that can bebuilt upon as required in Tables 2-1through 2-6 of the National FireProtection Association's "Flammableand Combustible Liquids Code," (1977 or1981), (incorporated by reference, see§ 260.11).§ 265.199 Special requirements forincompatible wastes.

(a) Incompatible wastes, orincompatible waste and materials, mustnot be placed in the same tank system,unless § 265.17(b) is complied with.

(b) Hazardous waste must not beplaced in a tank system that has notbeen decontaminated and thatpreviously held an incompatible wasteor material, unless § 265.17(b) iscomplied with.

§ 265.200 Waste analysis and trial tests.

In addition to performing the wasteanalysis required by § 265.13, the owneror operator must, whenever a tanksystem is to be used to treat chemicallyor to store a hazardous waste that issubstantially different from wastepreviously treated or stored in that tanksystem; or treat chemically a hazardouswaste with a substantially differentprocess than any previously used in thattank system:

(a) Conduct waste analyses and trialtreatment or storage tests (e.g., bench-scale or pilot-plant scale tests); or

(b) Obtain written, documentedinformation on similar waste undersimilar operating conditions to showthat the proposed treatment or storagewill meet the requirements of§ 265.194(a).

[Note.-Section 265.13 requires the wasteanalysis plan to include analyses needed tocomply with §§ 265.198 and 265.199. Section265.73 requires the owner or operator to placethe results from each waste analysis and trialtest. or the documented information, in theoperating record of the facility.l

§ 265.201 Special requirements forgenerators of between 100 and 1,000 kg/mo that accumulate hazardous waste Intanks.

(a) The requirements of this sectionapply to small quantity generators ofmore than 100 kg but less than 1,000 kgof hazardous waste in a calendar month,that accumulate hazardous waste intanks for less than 180 days (or 270 daysif the generator must ship the wastegreater than 200 miles), and do notaccumulate over 6,000 kg on-site at anytime.

(b) Generators of between 100 and1,000 kg/mo hazardous waste mustcomply with the following generaloperating requirements:

(1) Treatment or storage of hazardouswaste in tanks must comply with§ 265.17(b).

(2) Hazardous wastes or treatmentreagents must not be placed in a tank ifthey could cause the tank or its innerliner to rupture, leak, corrode, orotherwise fail before the end of itsintended life.

(3) Uncovered tanks must be.operatedto ensure at least 60 centimeters (2 feet)of freeboard, unless the tank is equippedwith a containment structure (e.g., dikeor trench), a drainage control system, ora diversion structure (e.g., standby tank)with a capacity that equals or exceedsthe volume of the top 60 centimeters (2feet) of the tank.

(4) Where hazardous waste iscontinuously fed into a tank, the tankmust be equipped with a means to stopthis inflow (e.g., waste feed cutoffsystem or by-pass system to a stand-bytank).

[Note.-These systems are intended to beused in the event of a leak or overflow fromthe tank due to a system failure (e.g., amalfunction in the treatment process, a crackin the tank, etc.).]. (c) Generators of between 100 and

1,000 kg/mo accumulating hazardouswaste in tanks must inspect, wherepresent:

(1) Discharge control equipment (e.g.,waste feed cutoff systems, by-passsystems, and drainage systems) at leastonce each operating day, to ensure thatit is in good working order;

(2) Data gathered from monitoringequipment (e.g., pressure andtemperature gauges) at least once eachoperating day to ensure that the tank isbeing operated according to its design;

(3) The level of waste in the tank atleast once each operating day to ensurecompliance with § 265.192(c);

(4) The construction materials of thetank at least weekly to detect corrosionor-leaking of fixtures or seams; and

(5) The construction materials of. andthe area immediately surrounding,

discharge confinement structures (e.g.,dikes) at least weekly to detect erosionor obvious signs of leakage (e.g., wetspots or dead vegetation).

[Note.-As required by § 265.15(c), theowner or operator must remedy anydeterioration or malfunction he finds.]

(d) Generators of between 100 and1,000 kg/mo accumulating hazardouswaste in tanks must, upon closure of thefacility, remove all hazardous wastefrom tanks, discharge control equipment.and discharge confinement structures.

(Note.-At closure, as throughout theoperating period, unless the owner oroperator can demonstrate, in accordancewith § 261.3(c) or (d) of this chapter, that anysolid waste removed from his tank is not ahazardous waste, the owner or operatorbecomes a generator of hazardous waste andmust manage it in accordance with allapplicable requirements of Parts 262, 263. and265 of this chapter.]

(e) Generators of between 100 and1,000 kg/mo must comply with thefollowing special requirements forignitable or reactive waste:

(1) Ignitable or reactive waste mustnot be placed in a tank, unless:

(i) The waste is treated, rendered, ormixed before or immediately afterplacement in a tank so that (A) theresulting waste, mixture, or dissolutionof material no longer meets thedefinition of ignitable or reactive wasteunder § 261.21 or § 261.23 of thisChapter, and (B) § 265.17(b) is compliedwith; or

(ii) The waste is stored or treated insuch a way that it is protected from anymaterial or conditions that may causethe waste to ignite or react; or

(iii) The tank is used solely foremergencies.

(2) The owner or operator of a facilitywhich treats or stores ignitable orreactive waste in covered tanks mustcomply with the buffer zonerequirements for tanks contained inTables 2-1 through 2-6 of the NationalFire Protection Association's"Flammable and Combustible LiquidsCode," (1977 or 1981) (incorporated byreference, see § 260.11).

(f0 Generators of between 100 and1,000 kg/mo must comply with thefollowing special requirements forincompatible wastes:

(1) Incompatible wastes, orincompatible wastes and materials, (seeAppendix V for examples) must not beplaced in the same tank, unless§ 265.17(b) is complied with.

(2) Hazardous waste must not beplaced in an unwashed tank whichpreviously held an incompatible waste

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or material, unless § 265.17(b) iscomplied with.

PART 270-EPA ADMINISTEREDPERMIT PROGRAMS: THEHAZARDOUS WASTE PERMITPROGRAM



Authority: Secs. 1006, 2002, 3005, 3007, 3019,and 7004 of the Solid Waste Disposal Act. asamended by the Resource Conservation andRecovery Act of 1976, as amended (42 U.S.C.6905, 6912, 6925, 6927, 6939, and 6974).

23. Section 270.14 is amended byrevising paragraphs (b)(5) and (b)(13) toread as follows:

§ 270.14 Contents of Part 0: generalrequirements.* * * *

(b) ***(5) A copy of the general inspection

schedule required by § 264.15(b); includewhere applicable, as part of theinspection schedule, specificrequirements in § § 264.174, 264.193(i),264.195, 264.226, 264.254, 264.273, and264.303.

(13) A copy of the closure plan and,where applicable, the post-closure planrequired by § § 264.112, 264 118, and264.197. Include, where applicable, aspart of the plans, specific requirementsin §§ 264.178, 204.197, 264.228, 264.258,264.280, 264 310, and 264.351.

24. Section 270.16, is revised to readas follows:

§ 270.16 Specific Part B Informationrequirements for tank systems.

Except as otherwise provided in§ 264.190, owners and operators offacilities that use tanks to store or treathazardous waste must provide thefollowing additional information:

(a) A written assessment that isreviewed and certified by anindependent, qualified, registeredprofessional engineer to the structuralintegrity and suitability for handling

hazardous waste of each tank system,as required under § § 264.191 and264.192;

(b) Dimensions and capacity of eachtank;

(c) Description of feed systems, safetycutoff, bypass systems, and pressurecontrols (e.g., vents);

(d) A diagram of piping,instrumentation, and process flow foreach tank system;

(e) A description of materials andequipment used to provide externalcorrosion protection, as required under§ 264.191(c);

(f) For new tank systems, a detaileddescription of how the tank system(s)will be installed in compliance with§ 264.192 (b), (c), (d), and (e);

(g) Detailed plans and description ofhow the secondary containment systemfor each tank system is or will bedesigned, constructed, and operated tomeet the requirements of § 264.193 (a),(b), (c), (d), (e), and (f);

(h) For tank systems for which avariance from the requirements of§ 264.193 is sought (as provided by§ § 264.193(g)):

(1) Detailed plans and engineering andhydrogeologic reports, as appropriate,describing alternate design andoperating practices that will, inconjunction with location aspects,prevent the migration of any hazardouswaste or hazardous constituents into theground water or surface water duringthe life of the facility, or

(2) A detailed assessment of thesubstantial present or potential hazardsposed to human health or theenvironment should a release enter theenvironment.

(i) Description of controls andpractices to prevent spills andoverflows, as required under§ 264.194(b); and

(j) For tank systems in whichignitable, reactive, or incompatiblewastes are to be stored or treated, adescription of how operating proceduresand tank system and facility design willachieve compliance with therequirements of § § 264.198 and 264.199.

(Information collection requirementscontained in paragraphs (a)-(j) wereapproved by the Office of Management andBudget under control number 2050-0050.)

§ 270.72 [Amended].25. In § 270.72, paragraph (e) is

amended by adding the followingsentence after the last sentence:

§ 270.72 Changes during Interim status.* * *t * *

(e) * * Changes under this section donot include changes made solely for thepurpose of complying with requirementsof § 265.193 for tanks and ancillaryequipment.

PART 271-REQUIREMENTS FORAUTHORIZATION OF STATEHAZARDOUS WASTE PROGRAMS


Authority: Sec. 1006, 2002(a), and 3006 ofthe Solid Waste Disposal Act, as amended bythe Resource Conservation and Recovery Actof 1976, as amended (42 U.S.C. 6905, 6912(a),and 6926].

§ 271.1 [Amended]27. In § 271.1, paragraph (j) is

amended by adding the following entryto Table I in chronological order by dateof publication:

TABLE 1.-REGULATIONS IMPLEMENTING THEHAZARDOUS AND SOLID WASTE AMEND-MENTS OF 1984

FederalDate Title of Regulation Registe

Reference

July 14, 1986. Hazardous Waste Tank 51 FRRegulations'-260.10; [Insert262.34(a)(1); 264.110 page264.1401 264.190- number]264.199; 265.110;265.140 265.190-265.200; 270.14(b);270.16; and 270.72(e).

'These regulations implement HSWA only to the extentthat they apply to tank systems owned or operated by smallquantity generators, establish leak detection requirements forall new underground tank systems, and establish permittingstandards for underground tank systems that cannot beentered for inspection.

[FR Doc. 86-15265 Filed 7-11-86; 8:45 am]BILLING COOS esoo-s0-M

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