Industrial hygiene

1. Introduction to Industrial Hygiene
MODULE 12

2. 2 ©2006 TEEX
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?

7. Toxic and Hazardous Substances
29 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
community
CHECK

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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)

13. Subtitles & Transitions
FOR EXAMPLE…
5 mg/M3,
Respirable
fraction
15 mg/M3,
Total dust
Particulates not
otherwise regulated
(PNOR)
1 ppm
Chlorine
50 ppm
Carbon monoxide
1000 ppm
Acetone
Ceiling
8-hr TWA
Substance
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 min
500 ppm
300 ppm
200 ppm
Toluene
5 min in
any 3 hrs
600 ppm
200 ppm
100 ppm
Styrene
10 min
50 ppm
20 ppm
Hydrogen
sulfide
10 min
50 ppm
25 ppm
10 ppm
Benzene
Notes
Peak
Ceiling
8-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/m3
Respirable dust
15 mg/m3
Nuisance dust
30mg/m3
% Sio2
Amorphous
10mg/m3
% Sio2 + 2
Crystalline Silica
(Respirable fraction)
PEL
Substance

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1910.1000(d) – Computation
formulae
 Time Weighted Average
 E = (C1T1 + C2T2 + …)/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

29. Protective Measures
Other 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?