Hydrogen sulfide exposure is covered under the following OSHA standards:
Worker Exposure Limits (Enforceable)
- General Industry: 29 CFR 1910.1000 TABLE Z-2, Toxic and hazardous substances
Exposures must not exceed 20 parts per million (ppm) (ceiling) with the following exception: if no other measurable exposure occurs during the 8-hour work shift, exposures may exceed 20 ppm, but not more than 50 ppm (peak), for a single time period up to 10 minutes.
- Construction: 29 CFR 1926.55 Appendix A, Gases, vapors, fumes, dusts, and mists
Sets exposure limit of 10 ppm (15 mg/m3) time-weighted average (TWA)
- Shipyard: 29 CFR 1915.1000 Table Z, Air contaminants
Sets exposure limit of 10 ppm (15 mg/m3) TWA
29 CFR 1910.119 App A and 29 CFR 1926.64 App A, List of highly hazardous chemicals, toxics and reactives (mandatory). Hydrogen sulfide is included in these lists of toxic and reactive highly hazardous chemicals and is considered to present a potential for a catastrophic event at or above 1500 pounds.
Below are standards that include OSHA requirements for evaluating (e.g., process safety, toxic and hazardous substances) and controlling (ventilation, respiratory protection) hydrogen sulfide exposures, including in confined spaces. Industry-specific requirements (construction, shipyard, marine terminals and longshoring) follow.
General Industry (29 CFR 1910)
- 1910 Subpart G, Occupational health and environmental control
- 1910.94, Ventilation
- 1910 Subpart H, Hazardous materials
- 1910.119, Process safety management of highly hazardous chemicals.
- 1910 Subpart I, Personal protective equipment
- 1910 Subpart J, General environmental controls
- 1910.146, Permit-required confined spaces
- 1910 Subpart Z, Toxic and hazardous substances
- 1910.1000, Air contaminants
- 1910.1200, Hazard communication
- Appendix A, Health hazard criteria (mandatory)
- 1910.1450, Occupational exposure to hazardous chemicals in laboratories
- Appendix A, National Research Council recommendations concerning chemical hygiene in laboratories (non-mandatory)
Construction (29 CFR 1926)
- 1926 Subpart D, Occupational health and environmental control
- 1926.55, Gases, vapors, fumes, dusts, and mists
- Appendix A, 1970 American Conference of Governmental Industrial Hygienists' Threshold Limit Values of Airborne Contaminants
- 1926 Subpart S, Underground construction, caissons, cofferdams, and compressed air
- 1926.800, Underground construction
Shipyard Employment (29 CFR 1915)
- 1915 Subpart B – Confined and enclosed spaces and other dangerous atmospheres in shipyard employment
- 1915.12, Precautions and the order of testing before entering confined and enclosed spaces and other dangerous atmospheres
- 1915 Subpart Z, Toxic and hazardous substances
- 1915.1000, Air contaminants
Marine Terminals (29 CFR 1917)
- 1917.1, Marine terminals, scope and applicability
- 1917.73, Terminal facilities handling menhaden and similar species of fish
Safety and Health Regulations for Longshoring (29 CFR 1918)
- 1918.1, Safety and health regulations for longshoring, scope and application
- 1918.94(f), Ventilation and atmospheric conditions. Employees shall not enter the hold when the hydrogen sulfide level exceeds 20 ppm ceiling or when the oxygen content is less than 19.5 percent, except in emergencies.
Letters of Interpretation (supplementary guidance that clarifies the application of an established Agency policy or procedure)
- The appropriate method for assessing hydrogen sulfide peak exposure levels. (September 28, 1995).
- Respiratory protection requirements for sour crude oil tank gauging operations. (April 25, 1989).
- Post-emergency response and medical surveillance requirements of HAZWOPER. (August 5, 1993).
- Respiratory protection as it relates to oil fields. (April 14, 1993).
- Interpretation of OSHA requirements for personal protective equipment to be used during marine oil spill emergency response operations. (September 11, 1995).
- Order of testing for permit spaces. (July 13, 1994).
- Potentially hazardous amine absorber pressure vessels used in refinery processing. (April 11, 1986).
- Use of Bureau of Mines approved gas mask canisters. (November 15, 1985).
- HHCs as it applies to hydrochloric acid, hydrofluoric acid, hydrogen sulfide, hydrogen cyanide. (June 9, 1994).
- Interpretation of substances with high acute toxicity as used in the occupational exposures to hazardous chemicals in the laboratory standard. (July 5, 1990).
- Respirator rules as applied to open hatch gauging of sour crude oil storage tanks. (June 11, 1990).
- Interpretation of "high degree of acute toxicity" under the laboratory standard. (July 30, 1990).
- NIOSH approved respirator during the period of an employee's escape from a chemical release of phosgene. (July 1, 1997).
- Release of hazardous chemicals from gas calibration bottles. (January 3, 1994).
- OSHA's policy on classification of a wet well as a Class 1, Division 1 location. (November 5, 1979).
- Fires involving spills or releases of hazardous substances. (June 17, 1991).
- Compliance and enforcement activities affected by the PELs decision. (August 5, 1993).
- The appropriate atmospheric monitoring equipment to the wine making industry for compliance with OSHA standard 1910.146. (June 21, 1995).
Other Exposure Limits for
NIOSH Recommended Exposure Limit (REL): 10 ppm, 10-minute ceiling
Concentration considered immediately dangerous to life and health (IDLH): 100 ppm
ACGIH® recommends a threshold limit value (TLV®) of 1 ppm as an 8-hour time weighted average (TWA) and a short-term exposure limit (STEL) of 5 ppm.
There are twenty-eight OSHA-approved State Plans, operating state-wide occupational safety and health programs. State Plans are required to have standards and enforcement programs that are at least as effective as OSHA's and may have different or more stringent requirements.