UNITED STATES DEPARTMENT OF THE INTERIOR

BUREAU OF OCEAN ENERGY MANAGEMENT, REGULATION AND ENFORCEMENT

Gulf of Mexico OCS Region

New Orleans, Louisiana

FINAL

SITE-SPECIFIC ENVIRONMENTAL ASSESSMENT

STRUCTURE-REMOVAL APPLICATION

ES/SR No. 10-86A, 87A

Assessment of the Environmental Impacts ofthe

Proposal to Remove Platforms A and B in

Chandeleur Area, Block 116 Lease OCS-G 10917

by HC Resources, LLC

Date Submitted: February 15, 2011

Commencement Date: Spring 2011

Prepared by:

Lisa McArdle

Environmental Protection Specialist

SUE-SPECIFIC ENVIRONMENTAL ASSESSMENT/FONSI/EIS DETERMINATION

HC Resources, LLC's applications to remove Platforms A and B in Chandeleur Area, Block 116, OCS-G 10917 using explosive severance methods have been reviewed. Our Site-Specific Environmental Assessment (SEA), ES/SR 10-86A, 87A, on the subject actions are complete and results in a Finding of No Significant Impact (FONSI). Based on the conclusions of the SEA, there is no evidence to indicate that the proposed action will significantly (40 CFR 1508.27) affect the quality of the human environment. Preparation of an environmental impact statement is not required. Mitigation is imposed to ensure environmental protection, consistent environmental policy and safety as required by the National Environmental Policy Act (NEPA), as amended; or measures needed for compliance with 40 CFR 1500.2(f) regarding the requirement for Federal agencies to avoid or minimize any possible adverse affects of their actions upon the quality of the human environment. This Finding is valid only insofar as the following conditions are imposed:

LARGE EXPLOSIVE-SEVERANCE SCENARIO Dl - MITIGATION PACKAGE: The operator is proposing explosive-severance activities that are covered under Large Blasting Category D l . Detailed pre- and post-detonation mitigation requirements can be found in Appendix A of this SEA.

PROHIBITION OF TAKING FISH INJURED/KILLED DURING EXPLOSIVE-SEVERANCE ACTIVITIES: Under the Magnuson-Stevens Fisheries Conservation and Management Act, 50 CFR 600.725 prohibits the use of explosives to take reef fish in the Exclusive Economic Zone. Consequently, those involved in removal operations must not take such stunned or killed fish on board their vessels. Should this happen, they could be charged by the National Marine Fisheries Service (NMFS) with violation of the Act.

PROGRESSIVE-TRANSPORT NOTIFICATION: In accordance with OCSLA requirements (30CFR§250.1727(g)), if at any point in your decommissioning schedule progressive-transport/"hopping" activities are required to section your jacket assembly or support material barge loading, a prior written request must be submitted and approval must be obtained from the Regional Supervisor/Field Operations. Your request to use progressive-transport must include a detailed procedural narrative and separate location plat for each "set-down" site, showing pipelines, anchor patterns for the derrick barge, and any known archaeological and/or potentially sensitive biological features. The diagram/map of the route to be taken from the initial structure location along the transport path to each site must also be submitted with your request. If the block(s) that you intend to use as "set-down" sites have not been surveyed as per NTL 2009-G39 and NTL No. 2005-G07, you may be required to conduct the necessary surveys/reporting prior to mobilizing on site and conducting any seafloor-disturbing activities.

OPERATIONS IN UNSURVEYED AREAS: Our review indicates that the structure proposed for removal is located within an area having a high potential for the location of historic shipwrecks but pre-dates the current requirement for archaeological survey. If you discover any site, structure, or object of potential archaeological significance (i.e., cannot be definitively identified as modem debris or refuse) while conducting operations, the provisions of 30 CFR 250.194(c) and NTL 2005-G07 require you to immediately halt seafloor-disturbing operations within 1,000 feet of the area of discovery and report this discovery to the Regional Supervisor of Leasing and Environment (RSLE) within 48 hours. Every reasonable effort must be taken to preserve the archaeological resource from damage until the RSLE has told you how to protect it.

PROTECTION OF POTENTIAL ARCHAEOLOGICAL RESOURCES: Our review indicates that your proposed activities are in the vicinity of the unidentified magnetic anomaly listed under separate cover, a feature that may represent a significant archaeological resource. In accordance with 30 CFR 250.194(b), you

must either (1) conduct an underwater archaeological investigation (diver and/or ROV investigations) to determine whether this feature represents an archaeological resource, or (2) ensure that all seafloor disturbing actions resulting from the proposed activities (e.g., site-clearance trawling, anchors, anchor chains, wire ropes, cables, etc.) avoid the unidentified feature by a distance greater than that listed under separate cover. If you conduct an underwater archaeological investigation, contact either Dr. Jack Irion at (504) 736-1742 or Dr. Christopher Horrell at (504) 736-2796 at least two weeks prior to performing operations to obtain the investigation methodology. If you choose to avoid the feature, include in your Post-removal Report as-built plats, at a scale of 1-in. = 1,000-ft. with DGPS accuracy, showing the position of anchors, anchor chains, wire ropes and cables deployed during the structure removal relative to the feature. Should you recover any artifacts or objects during site clearance activities you must submit digital photographs of each unidentified artifact/object with your Site Clearance Report. If you discover any object of potential archaeological significance (i.e., cannot be definitively identified as modem debris or refuse) while conducting operations, the provisions of 30 CFR 250.194(c) and NTL 2005-G07 require you to immediately halt operations and report this discovery to the Regional Supervisor of Leasing and Environment (RSLE) within 48 hours.

Section OCS Region

P a t e 7

INTRODUCTION AND BACKGROUND

The purpose of this Site-Specific Environmental Assessment (SEA) is to assess the specific impacts associated with proposed structure removal activities. This SEA implements the tiering process outhned iri 40 CFR 1502.20, which encourages agencies to tier environmental documents and eliminates repetitive discussions of the same issue. The SEA is based on a Programmatic Environmental Assessment (PEA) (USDOI, MMS 2005) which evaluates a broader spectrum of potential impacts resulting from all decommissioning operations in the Central and Western Gulf of Mexico (GOM) and the 181/189 Lease Sale Area of the Outer Continental Shelf (OCS). In addition to the analyses, a discussion of the legal and regulatory mandates to remove abandoned oil and gas structures from Federal Waters can be found in the PEA.

This SEA conforms to the Bureau of Ocean Energy Management, Regulation and Enforcement (BOEMRE) and other appropriate guidelines for preparing environmental assessments by tiering to the PEA, and by use of reference to related environmental documents. It presents site-specific data regarding the proposed structure removal activities and evaluates the potential impacts. Mitigation measures are contained in this document to lessen potential impacts. Preparation of this SEA has allowed the determination of whether a Finding of No Significant Impact (FONSI) is appropriate or whether further assessment of the proposal is necessary.

I . DESCRIPTION AND NEED FOR THE ACTION

HC Resources, LLC proposes to remove Platforms A and B in Chandeleur Area, Block 116, Lease OCS-G 10917 using explosive severance methods. The structures are located at a water depth of 116 to 121 feet, and lie approximately 35 miles from the nearest Louisiana shoreline. Operations will be conducted from an onshore support base in Venice, Louisiana. The operator will remove all casing, wiellhead equipment, and piling to a depth of at least 15 feet below the mudline. The piles and conductors will be severed using 80-200 lb. explosive charges. The maximum anchor radius employed by the lift vessel/derrick barge will be 4,500 feet. HC Resources, LLC's structure removal permit applications include additional information about the proposed activities and is incorporated herein by reference.

The proposed action is needed to allow HC Resources, LLC to comply with OCSLA regulations (30 CFR §250.1703 and §250.1725); wherein, operators are required to remove their facilities and associated seafloor obstructions from their leases within one year of lease termination or after a structure has been deemed obsolete or unusable. These regulations also require the operator to sever bottom-founded objects and their related components at least 15 feet BML (30 CFR §250.1728(a)). A discussion of the other legal and regulatory mandates to remove abandoned oil and gas structures from Federal Waters can be found in the PEA. According to the operator, the structures will be removed because there is no further production from the platforms (HC Resources, LLC, 2011).

B. ALTERNATIVES TO THE PROPOSED ACTION

The BOEMRE initially discussed various structure removal techniques in the Final Environmental Impact Statement (FEIS) for Proposed Oil and Gas Lease Sales 118 and 122 (USDOI, MMS, 1988) and in the PEA. Updated information is found in the FEIS for Gulf of Mexico OCS Oil and Gas Lease Sales: 2007-2012 (USDOI, MMS, 2007). Refer to the FEIS (USDOI, MMS, 1988 and 2007) and PEA for detailed information conceming alternative methods of structure removal. Alternatives to the proposed structure removal with mitigation originally submitted are:

A. NON-REMOVAL OF THE STRUCTURE

The alternative to the proposed structure removal as originally submitted is non-removal. Non-removal of the structure would represent a conflict with Federal legal and regulatory requirements, which mandate the timely removal of obsolete or abandoned structures within a period of one year after termination of the lease, or upon termination of a right-of-use and easement. Therefore, non-removal is not an acceptable alternative.

B. REMOVAL OF THE STRUCTURE WITH NON-EXPLOSIVE SEVERANCE METHODS ONLY

The BOEMRE discussed and analyzed decommissioning operations and various severance techniques in the PEA. Based upon this updated information, it was concluded that one of the most effective methods of severing targets both above and below the mudline was by using explosive-severance charges. Though non-explosive cutter methods are becoming more effective, they often have additional operational and logistical problems associated with their use. Primarily for this reason, HC Resources, LLC is proposing the use of explosive charges; therefore, limiting the operations to only non-explosive methods does not appear to be a feasible alternative for the removal of the subject structure.

Refer to the PEA referenced in the Introduction for detailed information conceming alternative methods of structure removal.

C. REMOVAL OF THE STRUCTURE AS PROPOSED WITH ADDED MITIGATION

Measures that HC Resources, LLC proposes to limit potential environmental effects are discussed in the structure removal application and are incorporated herein by reference. Outer Continental Shelf Operating Regulations, Notices to Lessees and Operators and other regulations and laws were identified throughout the PEA as existing mitigation for potential environmental effects associated with the proposed structure removal application. Additional information can be found in the PEA.

The following mitigative measures will also be included in BOEMRE's approval of the proposed structure removal to ensure environmental protection, consistent environmental policy, and safety as required by the National Environmental Policy Act.

LARGE EXPLOSIVE-SEVERANCE SCENARIO Dl - MITIGATION PACKAGE: The operator is proposing explosive-severance activities that are covered under Large Blasting Category D l . Detailed pre- and post-detonation mitigation requirements can be found in Appendix A.

PROHIBITION OF TAKING FISH INJURED/KILLED DURING EXPLOSIVE-SEVERANCE ACTIVITIES: Under the Magnuson-Stevens Fisheries Conservation and Management Act, 50 CFR 600.725 prohibits the use of explosives to take reef fish in the Exclusive Economic Zone. Consequently, those involved in removal operations must not take such stunned or killed fish on board their vessels. Should this happen, they could be charged by the National Marine Fisheries Service (NMFS) with violation of the Act.

PROGRESSIVE-TRANSPORT NOTIFICATION: In accordance with OCSLA requirements (30CFR§250.1727(g)), if at any point in your decommissioning schedule progressive-transport/" hopping" activities are required to section your jacket assembly or support material barge loading, a prior written request must be submitted and approval must be obtained from the Regional Supervisor/Field Operations. Your request to use progressive-transport must include a detailed procedural narrative and separate location plat for each "set-down" site, showing pipelines, anchor

patterns for the derrick barge, and any known archaeological and/or potentially sensitive biological features. The diagram/map of the route to be taken, from the initial structure location along the transport path to each site must also be submitted with your request. If the block(s) that you intend to use as "set-down" sites have not been surveyed as per NTL 2009-G39 and NTL No. 2005-G07, you may be required to conduct the necessary surveys/reporting prior to mobilizing on site and conducting any seafloor-disturbing activities.

OPERATIONS IN UNSURVEYED AREAS: Our review indicates that the structure proposed for removal is located within an area having a high potential for the location of historic shipwrecks but pre-dates the current requirement for archaeological survey. If you discover any site, structure, or object of potential archaeological significance (i.e., cannot be definitively identified as modem debris or refuse) while conducting operations, the provisions of 30 CFR 250.194(c) and NTL 2005-G07 require you to immediately halt seafloor-disturbing operations within 1,000 feet of the area of discovery and report this discovery to the Regional Supervisor of Leasing and Environment (RSLE) within 48 hours. Every reasonable effort must be taken to preserve the archaeological resource from damage until the RSLE has told you how to protect it.

PROTECTION OF POTENTIAL ARCHAEOLOGICAL RESOURCES: Our review indicates that your proposed activities are in the vicinity of the unidentified magnetic anomaly listed under separate cover, a feature that may represent a significant archaeological resource. In accordance with 30 CFR 250.194(b), you must either (1) conduct an underwater archaeological investigation (diver and/or ROV investigations) to determine whether this feature represents an archaeological resource, or (2) ensure that all seafloor disturbing actions resulting from the proposed activities (e.g., site-clearance trawling, anchors, anchor chains, wire ropes, cables, etc.) avoid the unidentified feature by a distance greater than that listed under separate cover. If you conduct an underwater archaeological investigation, contact either Dr. Jack Irion at (504) 736-1742 or Dr. Christopher Horrell at (504) 736-2796 at least two weeks prior to performing operations to obtain the investigation methodology. If you choose to avoid the feature, include in your Post-removal Report as-built plats, at a scale of 1-in. = 1,000-ft. with DGPS accuracy, showing the position of anchors, anchor chains, wire ropes and cables deployed during the structure removal relative to the feature. Should you recover any artifacts or objects during site clearance activities you must submit digital photographs of each unidentified artifact/object with your Site Clearance Report. If you discover any object of potential archaeological significance (i.e., cannot be definitively identified as modem debris or refuse) while conducting operations, the provisions of 30 CFR 250.194(c) and NTL 2005-G07 require you to immediately halt operations and report this discovery to the Regional Supervisor of Leasing and Environment (RSLE) within 48 hours.

III . ENVIRONMENTAL EFFECTS, SOCIOECONOMIC CONCERNS, AND OTHER CONSIDERATIONS.

In accordance with The National Environmental Policy Act (NEPA) of 1969, as amended (Pub. L. 91-190, 42 U.S.C. 4321-4347, January 1, 1970, as amended by Pub. L. 94-52, July 3, 1975, Pub. L. 94-83, August 9, 1975, and Pub. L. 97-258, . 4[b], Sept. 13, 1982) and the Council on Environmental Quality (CEQ) implementing regulations (40 CFR Sec. 1502.15) Affected Environment, the following potential environmental effects were identified from the proposed action. Mitigative measures are included to eliminate or reduce the potential effect from the proposed activities to a level of insignificance as described in 40 CFR Sec. 1508.27.

A. PHYSICAL ENVIRONMENT

Environmental geology, geologic hazards, meteorological conditions, physical and chemical oceanography, water quality and air quality are discussed in the PEA. The proposed structure removal activities are not in an area of sediment instability (mud flows, slumps, or slides). Other potential impacts from the proposed activities to the physical environment have been considered, but were deemed insignificant (40 CFR 1508.27) and are not discussed in this SEA.

B. BIOLOGICAL ENVIRONMENT

Coastal habitats, protected, endangered and threatened species (birds, marine mammals, and sea turtles), and sensitive marine habitats are discussed in the PEA. Based on the cumulative impact scenarios and assessments presented in the multisale EIS's and the potential effectiveness of protective NTL's and lease stipulations, it is expected that the short-term, incremental contribution of potential impacts from decommissioning activities (i.e. vessel discharges, explosive severance, explosive/nonexplosive-severance products, habitat removal/salvage, vessel anchoring, progressive transport, site-clearance trawling, and sediment redistribution) would not result in significant cumulative impact on coastal/wetlands habitat, fish resources, commercial and recreational fishing, benthic resources, and essential fish habitat of the GOM OCS.

A discussion of marine mammals occurring across the Gulf of Mexico (GOM) and an assessment of the potential impacts of structure removal activities on marine mammals can be found in the PEA. Twenty-nine species of marine mammals occur in the GOM (Davis et al., 2000). There are 28 species of cetaceans and 1 sirenian species (Jefferson et al., 1992). Five baleen whales (the northern right [Eubalaena glacialis], blue [Balaenoptera musculus], fin [Balaenoptera physalus], sei [Balaenoptera borealis], and humpback [Megaptera novaeangliae]), one toothed whale (the sperm whale [Physeter macrocephalus]), and one sirenian (the West Indian manatee [Trichechus manatus]) occur in the GOM and are listed as endangered.

Fritts et al. (1983) conducted aerial surveys across a 9,514 square-mile area of GOM waters. Results of these surveys indicate that the bottlenose dolphin is by far the most likely marine mammal to be encountered in the GOM. The BOEMRE and NMFS observers may be utilized to look for marine mammals prior to detonation of the primary charges at the removal site. If marine mammals are detected, detonation of the primary charges will be delayed until the animals are removed from the area. In spite of these precautions, a low probability exists that marine mammals could enter the blast area undetected and could be injured or killed by the underwater, subsurface detonations. Such an occurrence is considered highly unlikely and, with the indicated protective mitigation measures outlined in the Biological Opinion, the proposed structure removal activities are expected to have only a low impact on marine mammals.

A discussion of sea turtles occurring across the central and western GOM and an assessment of the potential impacts of structure removal activities on sea turtles can be found in the PEA. Five species of sea turtles (the green sea turtle [Chelonia mydas], the loggerhead [Caretta caretta], the hawksbill [Eretmochelys imbricata], the Kemp's ridley [Lepidochelys kempi], and the leatherback [Dermochelys coriacia]) are known to inhabit the waters of the GOM and the area of the proposed activities and therefore could be impacted by the operations. All sea turtles species inhabiting the GOM are listed as either endangered or threatened (Pritchard, 1997). Definitive information on the probability of encountering sea turtles at the removal site during explosive operations is scarce. NMFS and/or BOEMRE observers will be utilized to look for sea turtles prior to detonation of the primary charges. If sea turtles are detected at the structure removal site, , detonation of the primary charges will be delayed until the animals are removed from the area. The possibility exists that sea turtles could enter the blast areas undetected and could be injured or killed by the underwater, subsurface detonations. However, with

the indicated protective mitigation measures, we expect the proposed structure removal activities to have only a low impact on sea turtles. NMFS authorized a cumulative incidental take for this category action, but with all the precautions to be taken as mitigating measures, it is unlikely these proposed operations will affect any sea turtles.

NMFS concluded that this category of structure removal activities will not likely jeopardize the continued existence of any threatened or endangered species under their purview. No critical habitat has been designated in the project area. Additionally, they concluded that this type of "standard" structure removal activity may result in injury or mortality of loggerhead, Kemp's ridley, green, hawksbill, and leatherback turtles. Therefore, they established a cumulative level of incidental take and discussed various measures necessary to monitor and minimize this impact. NMFS noted that no incidental taking of marine mammals was authorized under Section 101(a)(5) of the Marine Mammal Protection Act of 1972 in connection with this category of structure removal activities.

Other potential impacts from the proposed activities to the biologic environment have been considered, but were deemed insignificant (40 CFR 1508.27) and are not discussed further in this SEA.

C. OTHER CONSIDERATIONS

A discussion of socioeconomic factors, archaeological resources, commercial and recreational fisheries, military warning areas, explosive dumping areas, navigation and shipping areas, pipelines, cables, other mineral uses, and health and human safety can be found in the PEA referenced in the Introduction. Mitigation has been applied to minimize impacts to these factors where appropriate and is discussed elsewhere in this SEA. Other environmental effects have been considered, but potential impacts from the proposed activities were deemed insignificant (40 CFR 1508.27) and are not discussed further in this SEA.

Major impact-producing factors of decommissioning activities that could affect both prehistoric and historic archaeological resources are direct physical contact from anchoring, progressive-transport (i.e., jacket-hopping), and trawling activities associated with site clearance. Blocks with a high probability for the occurrence of prehistoric and/or historic archaeological resources are listed in the CPA, EPA, and WPA EIS's. Prehistoric archaeological resources include sites, structures, and objects such as shell middens, earth middens, campsites, kill sites, tool manufacturing areas, ceremonial complexes, and earthworks. Blocks with a high probability for prehistoric archaeological resources are found landward of a line that roughly follows the 60-m bathymetric contour.

Structure removal activities with the most potential to impact archaeological resources include anchoring, jacket hopping, and trawling associated with the site clearance process. Anchoring associated with platform removal may physically impact prehistoric and/or historic archaeological resources. The removal of offshore structures through progressive-transport (or jacket-hopping) has the ability to impact prehistoric and/or historic archaeological resources along the path used to move into shallow water. The activity most likely to have the greatest impact on prehistoric and/or historic archaeological resources comes from trawling associated with the site clearance and verification process. The use of shrimp trawlers to verify seafloor clearance can seriously impact any archaeological resources encountered, particularly in lease blocks that were developed prior to the requirement of an archaeological survey and assessment.

However, conditional to archaeological review of the proposed action along with the implementation of proper avoidance mitigation, the potential impacts of the proposed action on archaeological resources are not expected to be significant.

The BOEMRE continues to consider the overall impacts of structure removals on commercial fishing to be low. The BOEMRE policy of encouraging an active rigs-to-reefs program will help to offset cumulative structure removal impacts to fisheries resources.

D. UNAVOIDABLE ADVERSE IMPACTS

A discussion of unavoidable adverse impacts can be found in the PEA. Two areas of ongoing concern have been the potential impact to protected, threatened, and/or endangered species and potential loss of habitat to the marine environment. Both topics are discussed in the PEA and previously in this document. A more recent issue of concern has surfaced regarding the impacts of explosive structure removals on reef fish stocks. Although the impacts to commercial and recreational fisheries are considered to be low, further studies information about this issue will be available in the future. Other unavoidable adverse impacts are considered to be minor.

IV. PUBLIC OPINION

A discussion of public concerns regarding structure removals can be found in the PEA. No public comments have been received regarding the proposed structure removal operations.

V. CONSULTATION AND COORDINATION

Consultation and interagency coordination efforts were undertaken during and subsequent to the preparation of the 2005 PEA. NMFS concluded that this category of structure removal activities will not likely jeopardize the continued existence of any threatened or endangered species under their purview. Additionally, they concluded that this type of "standard" structure removal activity may result in injury or mortality of loggerhead, Kemp's ridley, green, hawksbill, and leatherback turtles. Therefore, they established a cumulative level of incidental take and discussed various measures necessary to monitor and minimize this impact. As a result of these efforts, a Biological Opinion (BiOp) and Incidental Take Statement (ITS) were issued in August of 2006. In accordance with the provisions of Section 7 of the Endangered Species Act (ESA), as amended, the proposed structure removal operations are covered by the BiOp and ITS, which address the explosive-severance categories and site-clearance trawling activities analyzed in the PEA (USDOC, 2006).

A similar incidental-take rulemaking effort was conducted with NMFS under Subpart I of the Marine Mammal Protection Act (MMPA) to cover protected marine mammals that could be impacted by removal operations. The Final Rule was published on June 19, 2008 (FR, 2008). The survey mitigation prescribed under the promulgated regulations are nearly identical to those proposed/analyzed in the 2005 PEA and included as terms and conditions of the 2006 ESA BiOp and ITS. Similarly, the mitigation recommended and analyzed in this SEA was developed from the programmatic NEPA, ESA, and MMPA guidance.

VI. BIBLIOGRAPHY AND SPECIAL REFERENCES

Davis, R.W., W.E. Evans, and B. Wursig. 2000. Cetaceans, Sea Turtles and Seabirds in the Northem Gulf of Mexico: Distribution, Abundance and Habitat Associations. Volume II : Technical Report. U.S. Dept. of the Interior, Geological Survey, Biological Resources Division, USGS/BRD/CR-1999-0006 and U.S. Dept. of the Interior, Minerals Management Service, Gulf of Mexico Region, New Orleans LA. OCS Study MMS 2000-003. 346 pp.

Federal Register (FR). 2008. Taking and Importing Marine Mammals; Taking Marine Mammals Incidental to the Explosive Removal of Offshore Structures in the Gulf of Mexico; Final Rule (50 CFR Part 216, Subpart S). 73 FR 119. 34875-34894 pp.

Fritts, T.H., A.B. Irvine, R.D. Jennings, L.A. Collum, W. Hoffman, and M.A. McGehee. 1983. Turtles, Birds, and Mammals in the Northem Gulf of Mexico and Nearby Atlantic Waters. U.S. Fish and Wildlife Service, Division of Biological Services, Washington, D.C.

HC Resources, LLC 2011. Proposed OCS Platform Removal Applications: Lease OCS-G 10917, Platforms A and B, Chandeleur Area Block 116, Offshore, Louisiana.

Jefferson, T.A., S. Leatherwood, L.K.M. Shoda, and R.L. Pitman. 1992. Marine Mammals of the Gulf of Mexico: A Field Guide for Aerial and Shipboard Observers. College Station, TX: Texas A&M University Printing Center. 92 pp.

Pritchard, P.C.H. 1997. Evolution, Phylogeny, and Current Status. In: Lutz, P.L. and Musivk, J.A., eds. The Biology of Sea Turtles. Boca Raton, FL: CRC Press. Pp. 1-28.

U.S. Department of Commerce. NMFS. 2006. Biological Opinion/Incidental Take Statement Conceming Permitting Structure Removal Operations on the Gulf of Mexico Outer Continental Shelf. 132 pp. National Marine Fisheries Service, Endangered Species Division; Silver Spring, MD.

U.S. Department of the Interior. Minerals Management Service. 1988. Final Environmental Impact Statement (FEIS) for Proposed Oil and Gas Lease Sales 118 and 122 (USDOI, MMS, 1988)

U.S. Department of the Interior. Minerals Management Service. 2007. Final Environmental Impact Statement. Gulf of Mexico Oil and Gas Lease Sales: 2007-2012: Western Planning Area Sales 204, 207, 210, 215, and 218; Central Planning Area Sales 205, 506, 208, 213, 216 and 222. OCS EIS/EA MMS 2007-018. Vol. I and E. Gulf of Mexico OCS Region, New Orleans, LA.

U.S. Department of the Interior. Minerals Management Service. 2005. Programmatic Environmental Assessment. Structure-Removal Operations on the Gulf of Mexico Outer Continental Shelf. OCS EIS/EA 2005-013. Gulf of Mexico OCS Region, New Orleans, LA.

VII. PREPARER: Lisa McArdle, Environmental Protection Specialist

APPENDIX A

MITIGATION REQUIREMENTS

Mitigation Requirements

LARGE EXPLOSIVE-SEVERANCE SCENARIO D l - MITIGATION PACKAGE: The operator is proposing explosive-severance activities that are covered under Large Blasting Category D l . Detailed pre- and post-detonation mitigation requirements can be found below.

PROHIBITION OF TAKING FISH INJURED/KILLED DURING EXPLOSIVE-SEVERANCE ACTIVITIES: Under the Magnuson-Stevens Fisheries Conservation and Management Act, 50 CFR 600.725 prohibits the use of explosives to take reef fish in the Exclusive Economic Zone. Consequently, those involved in removal operations must not take such stunned or killed fish on board their vessels. Should this happen, they could be charged by the National Marine Fisheries Service (NMFS) with violation of the Act. If you have questions, contact NMFS at (727) 824-5116.

PROGRESSIVE-TRANSPORT NOTIFICATION: In accordance with OCSLA requirements (30CFR§250.1727(g)), if at any point in your decommissioning schedule progressive-transportThopping" activities are required to section your jacket assembly or support material barge loading, a prior written request must be submitted and approval must be obtained from the Regional Supervisor/Field Operations. Your request to use progressive-transport must include a detailed procedural narrative and separate location plat for each "set-down" site, showing pipehnes, anchor patterns for the derrick barge, and any known archaeological and/or potentially sensitive biological features. The diagram/map of the route to be taken from the initial structure location along the transport path to each site must also be submitted with your request. If the block(s) that you intend to use as "set-down" sites have not been surveyed as per NTL 2009-G39 and NTL NO. 2005-G07, you may be required to conduct the necessary surveys/reporting prior to mobilizing on site and conducting any seafloor-disturbing activities.

OPERATIONS IN UNSURVEYED AREAS: Our review indicates that the structure proposed for removal is located within an area having a high potential for the location of historic shipwrecks but pre-dates the current requirement for archaeological survey. If you discover any site, structure, or object of potential archaeological significance (i.e., cannot be definitively identified as modem debris or refuse) while conducting operations, the provisions of 30 CFR 250.194(c) and NTL 2005-G07 require you to immediately halt seafloor-disturbing operations within 1,000 feet of the area of discovery and report this discovery to the Regional Supervisor of Leasing and Environment (RSLE) within 48 hours. Every reasonable effort must be taken to preserve the archaeological resource from damage until the RSLE has told you how to protect it.

PROTECTION OF POTENTIAL ARCHAEOLOGICAL RESOURCES: Our review indicates that your proposed activities are in the vicinity of the unidentified magnetic anomaly listed under separate cover, a feature that may represent a significant archaeological resource. In accordance with 30 CFR 250.194(b), you must either (1) conduct an underwater archaeological investigation (diver and/or ROV investigations) to determine whether this feature represents an archaeological resource, or (2) ensure that all seafloor disturbing actions resulting from the proposed activities (e.g., site-clearance trawling, anchors, anchor chains, wire ropes, cables, etc.) avoid the unidentified feature by a distance greater than that listed under separate cover. If you conduct an underwater archaeological investigation, contact either Dr. Jack Irion at (504) 736-1742 or Dr. Christopher Horrell at (504) 736-2796 at least two weeks prior to performing operations to obtain the investigation methodology. If you choose to avoid the feature, include in your Post-removal Report as-built plats, at a scale of 1-in. = 1,000-ft. with DGPS accuracy, showing the position of anchors, anchor chains, wire ropes and cables deployed during the structure removal relative to the feature. Should you recover any artifacts or objects during site clearance activities you must submit digital photographs of each unidentified artifact/object with your Site Clearance Report. If you discover any object of potential archaeological significance (i.e., cannot be definitively identified as

A-l

modem debris or refuse) while conducting operations, the provisions of 30 CFR 250.194(c) and NTL 2005-G07 require you to immediately halt operations and report this discovery to the Regional Supervisor of Leasing and Environment (RSLE) within 48 hours.

.A-2

Large Blasting Category Dl An operator proposing shelf-based (<200 m), explosive-severance activities conducted under the

Large blasting category will be limited to 80 to 200-lb charge sizes deployed below mudline (BML) and will be required to conduct all requisite monitoring during daylight hours out to the associated impact-zone radii of 941 m (3,086 ft).

Required Observers

Generally, two NMFS observers (PROP or contracted personnel) are required to perform marine protected species (MPS) detection surveys for large-blasting, shelf scenarios D l and D3. If necessary, the PROP Coordinator will determine if additional observers are required to compensate for the complexity of severance activities and or structure configuration. In addition to meeting all reporting requirements, the NMFS observers would:

• Brief affected crew and severance contractors of the monitoring efforts and notify topsides personnel to report any sighted MPS to the observer or company representative immediately;

• Establish an active line of communication (i.e., 2-way radio, visual signals, etc.) with company and blasting personnel; and

• Devote the entire, uninterrupted survey time to MPS monitoring.

Pre-Det Monitoring

Before severance charge detonation, both NMFS observers will conduct a 120 min surface monitoring survey of the impact zone. The monitoring will be conducted from the highest vantage point available from either the decommissioning target or proximal surface vessels. Once the surface monitoring is complete (i.e., the impact zone cleared of MPS), one of the NMFS observers will transfer to a helicopter to conduct a 45 min aerial monitoring survey. As per PROP-approved guidelines, the helicopter will transverse the impact zone at low speed/altitude in a specified grid pattern. If during the aerial survey a MPS is:

• Not sighted, proceed with the detonation;

• Sighted outbound and continuously tracked clearing the impact zone, proceed with the detonation after the monitoring time is complete to avoid reentry;

• Sighted outbound and the MPS track is lost (i.e., the animal dives below the surface),

o Halt the detonation,

o Wait 30 min, and

o Reconduct the 45 min aerial monitoring survey; or

• Sighted inbound,

o Halt the detonation,

o Wait 30 min, and

o Reconduct the 45 min aerial monitoring survey.

A-3

Post-Det Monitoring

After severance charge detonation, the NMFS observer will conduct a 30 min aerial monitoring survey of the impact zone to detect for impacted MPS. If a MPS is observed shocked, injured, or killed, the operations will cease, attempts will be made to collect/resuscitate the animal, and NMFS SERO will be contacted as per the take event procedures described on page F-9 of the Programmatic EA (MMS 2005-013). If no MPS are observed to be impacted by the detonation, the NMFS observer will record all of the necessary information as per the conditions detailed in BOEMRE's permit approval letter and PROP guidelines for the preparation of a trip report.

If unforeseen conditions or events occur during a large-blasting operation that necessitates monitoring requirements which fall outside of the applicable regulations, the NMFS observer will contact the PROP coordinator and/or BOEMRE's GOM Region for additional guidance. A flowchart of the monitoring process and associated survey times for large-severance scenario Dl is below.

PRE-OET DETOMATION — POST-DET

Pre-Det . ' Pre-Det Surface Aerial Survey Survey

• Hatt detonation.

• Reconduct Aerial Survey

T Iribou'ri'd

MPS Sighted?

fOulbotincJ1'

Continue montforing

If observer loses track/ Hatt'donati on

Reconduct Aerial survey If the Mp S .Is. s igrtted.and

co rrti h uai ly trac kejf -c learln g the impact zone,

proceed to avoid reentry

Post-Det Aerial Survey

Scenario

,Pre-Det .Surface

IA]

Pre-Det Aerial

PI

Waiting Period

art y • v • t. - * v [Cl ,

\fpst-D>et ^ Aerial

[Dl Scenario

(Minutes) D1 120 45 30 30

A-4