- Safety and Health Topics
- Hydrogen Sulfide
Hydrogen sulfide (also known as H2S, sewer gas, swamp gas, stink damp, and sour damp) is a colorless gas known for its pungent "rotten egg" odor at low concentrations. It is extremely flammable and highly toxic.
Hydrogen sulfide is used or produced in a number of industries, such as
- Oil and gas refining
- Pulp and paper processing
- Rayon manufacturing
Hydrogen sulfide also occurs naturally in sewers, manure pits, well water, oil and gas wells, and volcanoes. Because it is heavier than air, hydrogen sulfide can collect in low-lying and enclosed spaces, such as manholes, sewers, and underground telephone vaults. Its presence makes work in confined spaces potentially very dangerous.
The health effects of hydrogen sulfide depend on how much H2S a worker breathes and for how long. However, many effects are seen even at low concentrations. Effects range from mild, headaches or eye irritation, to very serious, unconsciousness and death.
Hydrogen sulfide exposure addressed in specific OSHA standards for General Industry, Shipyard Employment and Construction.
Provides information on the safety and health effects of hydrogen sulfide.
Hydrogen Sulfide in Workplaces
Discusses where hydrogen sulfide may be found.
Provides information on evaluating whether hydrogen sulfide gas is present and how to eliminate or control the source when possible.
Provides links and references to additional resources related to hydrogen sulfide.
Workers have the right to:
- Working conditions that do not pose a risk of serious harm.
- Receive information and training (in a language and vocabulary the worker understands) about workplace hazards, methods to prevent them, and the OSHA standards that apply to their workplace.
- Review records of work-related injuries and illnesses.
- File a complaint asking OSHA to inspect their workplace if they believe there is a serious hazard or that their employer is not following OSHA's rules. OSHA will keep all identities confidential.
- Exercise their rights under the law without retaliation, including reporting an injury or raising health and safety concerns with their employer or OSHA. If a worker has been retaliated against for using their rights, they must file a complaint with OSHA as soon as possible, but no later than 30 days.
For additional information, see OSHA's Workers page.
How to Contact OSHA
Under the Occupational Safety and Health Act of 1970, employers are responsible for providing safe and healthful workplaces for their employees. OSHA's role is to ensure these conditions for America's working men and women by setting and enforcing standards, and providing training, education and assistance. For more information, visit www.osha.gov or call OSHA at 1-800-321-OSHA (6742), TTY 1-877-889-5627.
Hydrogen sulfide is one of the leading causes of workplace gas inhalation deaths in the United States. According to the Bureau of Labor Statistics (BLS), hydrogen sulfide caused 60 worker deaths between 2001 and 2010.
Why is hydrogen sulfide so deadly?
- It is highly flammable and toxic, even at low concentrations.
- It is heavier than air and may travel along the ground.
- It can build up in low-lying areas, and in confined spaces (including enclosed, poorly ventilated areas, such as manure pits, sewers, manholes, and underground vaults).
- After a while at low or more quickly at high concentrations, you can no longer smell it to warn you it's there.
- It can quickly, almost immediately, overcome unprepared workers, including rescue workers.