Occupational Safety and Health Administration OSHA

Hydrogen Sulfide

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Hydrogen Sulfide Menu


Hydrogen sulfide exposure addressed in specific OSHA standards for general industry, shipyard employment and construction. This section highlights OSHA standards and documents related to hydrogen sulfide.

OSHA Standards
General Industry (29 CFR 1910)
Related Information
Subpart G – Occupational Health and Environmental Control 1910.94, Ventilation
Subpart H – Hazardous Materials 1910.119, Process safety management of highly hazardous chemicals
Subpart I – Personal Protective Equipment  
1910.134, Respiratory protection
Subpart J – General Environmental Controls 1910.146, Permit-required confined spaces
Subpart Z – Toxic and Hhazardous Substances 1910.1000, Air contaminants
1910.1200, Hazard communication
1910.1450, Occupational exposure to hazardous chemicals in laboratories
Maritime (29 CFR 1915, 1917, 1918)
Related Information
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
1917 Subpart A – General Provisions 1917.1, Scope and applicability
1917 Subpart D – Specialized Terminals 1917.73, Terminal facilities handling menhaden and similar species of fish  
1918 Subpart A – General Provisions 1918.1, 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.  
1918 Subpart I – General Working Conditions 1918.94, Catch of menhaden and similar species of fish  
Construction (29 CFR 1926)
Related Information
Subpart D – Occupational Health and Environmental Controls 1926.55, Gases, vapors, fumes, dusts, and mists
Subpart S – Underground Construction, Caissons, Cofferdams, and Compressed Air 1926.800, Underground construction
Additional Letters of Interpretation
(supplementary guidance that clarifies the application of an established Agency policy or procedure)

Note: The “Letters of interpretation” bullets above link to letters related to each OSHA standard. The letters in this list provide additional information that is not necessarily connected to a specific OSHA standard highlighted on this Safety and Health Topics page.

State Standards

There are 28 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.

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

Other Exposure Limits for Hydrogen Sulfide

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.

29 CFR 1910.119 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.

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