1. Introduction to Industrial Hygiene
MODULE 12

2. 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

3. Steps to Protect Employees
Anticipate potential hazards
Recognize potential hazards
Evaluate exposure and risk
Control exposure and risk
(Not just for health hazards)

4. Hierarchy of Controls Engineering controls: Remove hazard
Process change, Chemical substitution
Ventilation, Shielding, Guarding
Requires little or no employee action
Administrative controls: Manage exposure
Worker rotation, Procedures, Training
Trench shoring, Controlled access areas
Requires employee action

5. Hierarchy of Controls 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

6. 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

8. 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

9. 29 CFR Subpart Z 1910.1001-1096: 1910.1200 Hazard Communication
Specific regulations for individual substances including:
asbestos ( );
lead ( );
bloodborne pathogens ( ), and others
Hazard Communication

10. CHECK 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

11. 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

12. 1910.1000(a) - Table Z-1 8-hour Time Weighted Averages (TWA) Units:
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
Table Z-1 Examples
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
Subtitles & Transitions
FOR EXAMPLE…

14. (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
Cadmium
Formaldehyde
Methylene chloride

15. 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

16. 1910.1000(b) - Table Z-2 Examples 10 min 500 ppm 300 ppm 200 ppm
Toluene
5 min in any 3 hrs
600 ppm
100 ppm
Styrene
50 ppm
20 ppm
Hydrogen sulfide
25 ppm
10 ppm
Benzene
Notes
Peak
Ceiling
8-hr TWA
Substance

17. 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

18. 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)

19. 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

20. 1910.1000(d) – Computation formulae
Time Weighted Average
E = (C1T1 + C2T2 + …)/total time
Total time used = 8 hours
Example in § (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

21. 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

22. 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:

23. Chemical-Specific Standards
Asbestos
Inorganic Arsenic
Lead
Chromium (VI) (revised 2006)
Cadmium
Benzene
Oil and gas drilling, production, servicing exempt
Formaldehyde

24. 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

25. 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

26. 1910.1096 Ionizing radiation OSHA standards cover NORM and TENORM
Exposures must be kept within limits even if sources are natural

27. 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

28. 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

30. 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)

31. 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

32. 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

33. 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

34. Protective Measures
How are exposures to health hazards evaluated on your site?
How are they controlled?