Introduction to Industrial HygieneMODULE 12

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What is Industrial Hygiene?

Industrial hygiene is the science of anticipating, recognizing, evaluating, and controlling workplace conditions that may cause workers' injury or illness.

Key factors: Employee exposure to hazards Control for hazards to protect workers

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Steps to Protect Employees

Anticipate potential hazards Recognize potential hazards Evaluate exposure and risk Control exposure and risk (Not just for health hazards)

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Hierarchy of Controls

1. Engineering controls: Remove hazard Process change, Chemical substitution Ventilation, Shielding, Guarding Requires little or no employee action

2. Administrative controls: Manage exposure

Worker rotation, Procedures, Training Trench shoring, Controlled access areas Requires employee action

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Hierarchy of Controls

3. Personal protective equipment (PPE) Respirators, Gloves, Boots, Clothing Fall protection equipment, Hard hats Requires individual employee action Last line of defense, behind engineering

and administrative controls Addressed in 29 CFR 1910 Subpart I

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Chemical exposures in oil and gas operations

What chemicals are used in oil and gas operations?

How can employees be exposed? What toxic effects do these chemicals

have? How can employees be protected from

these effects?

Toxic and Hazardous Substances29 CFR Subpart Z

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29 CFR Subpart Z

1910.1000 Air Contaminants: Includes Z tables: worker exposure limits

for specific listed substances Employee exposure cannot exceed limits Tables Z-1, Z-2, Z-3 each have their own

requirements

PEL = Permissible Exposure Limit

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29 CFR Subpart Z

1910.1001-1096: Specific regulations for individual

substances including: asbestos (1910.1001); lead (1910.1025); bloodborne pathogens (1910.1030), and others

1910.1200 Hazard Communication

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1910.1000(a) - Table Z-1

Derived from 1968 ACGIH TLVs American Conference of Governmental

Industrial Hygienists Threshold Limit Values Levels thought to cause no significant

adverse health effects in the majority of the communityCHECK

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1910.1000(a) - Table Z-1

Lists common workplace chemicals Two types of limits:

8-hour Time Weighted Average (TWA) or Ceiling (C) limits

Employee exposure shall at no time exceed a ceiling (C) exposure limit

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1910.1000(a) - Table Z-1

8-hour Time Weighted Averages (TWA) Employee exposure shall not exceed 8-

hour TWA in any 8-hour work shift of a 40-hour work week

Calculations illustrated in (d)

Units: Parts per million (ppm) Milligrams per cubic meter (mg/m3)

Subtitles & TransitionsFOR EXAMPLE…

5 mg/M3,

Respirable fraction

15 mg/M3,

Total dust

Particulates not otherwise regulated (PNOR)

1 ppmChlorine

50 ppmCarbon monoxide

1000 ppmAcetone

Ceiling8-hr TWASubstance

Table Z-1 Examples

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1910.1000(b) - Table Z-2

Adopted from ANSI standards (American National Standards Institute)

Expanded standards developed for some of the substances found in Z-2, including: Benzene 1910.1028 Cadmium 1910.1027 Formaldehyde 1910.1048 Methylene chloride 1910.1052

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1910.1000(b) - Table Z-2

Table Z-2 expresses exposure limits as: 8-hour TWA Ceiling Peak

If a substance has both ceiling and peak limits: peak = level never to be exceeded

Exposure levels over the ceiling but under the peak must comply with margin notes in table

TWA must still not be exceeded

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1910.1000(b) - Table Z-2 Examples

10 min500 ppm300 ppm200 ppmToluene

5 min in any 3 hrs

600 ppm200 ppm100 ppmStyrene

10 min50 ppm20 ppmHydrogen sulfide

10 min50 ppm25 ppm10 ppmBenzene

NotesPeakCeiling8-hr TWA

Substance

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1910.1000(c) - Table Z-3

8-hour TWA limits for forms of silica Adopted from ACGIH TLVs

SiO2 : basic component of sand, granite

Quartz: 2nd most common mineral Quartz sand (crystalline silica) used to

fracture rock formations in wells Silica in barite, lignite, and bentonite

mud additives

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Health Effects of Silica

Silicosis Irreversible but

preventable Most commonly

associated with silica dust

Other possible effects: Lung cancer Some auto-immune

diseases

(Scanning electron micrograph by William Jones, Ph.D., compliments of OSHA)

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1910.1000(c) - Table Z-3

5 mg/m3Respirable dust

15 mg/m3Nuisance dust

30mg/m3

% Sio2 Amorphous

10mg/m3

% Sio2 + 2

Crystalline Silica(Respirable fraction)

PELSubstance

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1910.1000(d) – Computation formulae

Time Weighted Average E = (C1T1 + C2T2 + …)/total time

Total time used = 8 hours Example in § 1910.1000(d)(1)(ii) What about different work schedules?

Varies by chemical Most chemicals: Worst 8 hours of shift Lead: adjusted by hours worked Interpretation – Foulke letter, 1997

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1910.1000(d) – Computation formulae

Exposure to Chemical Mixtures Em = (C1/L1) + (C2/L2) + … + (Cn/Ln)

If Em > 1, employee is overexposed

Assumptions: Chemicals’ effects are additive Dose is proportional to C T

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1910.1000(e) – To achieve compliance

Administrative or engineering controls first wherever feasible

When those are not feasible for full compliance: protective equipment or other protective measures

Equipment or technical measures must be approved by competent industrial hygienist or qualified person

Respirators: 1910.134

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Chemical-Specific Standards

1910.1001 Asbestos 1910.1018 Inorganic Arsenic 1910.1025 Lead 1910.1026 Chromium (VI) (revised 2006) 1910.1027 Cadmium 1910.1028 Benzene

Oil and gas drilling, production, servicing exempt

1910.1029 Formaldehyde

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1910.1020 Access to employee exposure and medical records

Employees, representatives, and OSHA have right of access

Preserved for 30 years, with exceptions Employee consent for medical records OSHA access order posted if

identifiable Trade secrets Employee information

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1910.1030 Bloodborne Pathogens

Occupational exposure: Reasonably anticipated skin, eye, mucous

membrane, or parenteral contact With blood or other potentially infectious

materials (OPIM) e.g. certain body fluids, tissues

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1910.1096 Ionizing radiation

OSHA standards cover NORM and TENORM

Exposures must be kept within limits even if sources are natural

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1910.1201 Retention of DOT markings, placards and labels

Retain markings on packages received until clean enough to remove hazard

Freight container or vehicle retains placards until materials removed enough

Readily visible Non-bulk packages not to be reshipped:

Hazard Communication labels OK

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1910.1450 Hazardous chemicals in laboratories

For laboratory use only Supersedes other standards in Subpart

Z – except: PELs Prohibition of eye and skin contact

Exposure monitoring and medical surveillance for those over action levels

Protective MeasuresOther Standards and

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General Duty Clause

Recognized hazards may be cited If there is no PEL:

Consensus or proprietary standards ANSI, ACGIH, AIHA

Industry Best Practices Manufacturer Recommendations (MSDS)

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Biological Hazards

Potentially infectious material exposure Contagious diseases e.g. influenza Vector-borne diseases e.g. Malaria,

Lyme disease Fungi e.g. mold, spores Toxins e.g. endotoxin Allergens / sensitizers e.g. pollen, red

cedar

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Physical and Radiological Hazards

Heat or cold (General Duty Clause) Vibration (General Duty Clause) Noise (1910 Subpart G) Non-ionizing radiation (electromagnetic,

light) (1910 Subpart G) Ionizing radiation

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Other Standards

29 CFR 1926 Subpart D: Occupational Health and Environmental Controls Construction operations only

API RP 54 Noise rules allow for 12 hour shifts Handling drilling fluid chemicals and

additives

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Protective Measures

How are exposures to health hazards evaluated on your site?

How are they controlled?