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Hydrogen Sulfide


CAS No. 7783-06-4

Hydrogen sulfide (H₂S) is a colorless gas with a strong odor of rotten eggs. Exposure to hydrogen sulfide may cause irritation to the eyes and respiratory system. It can also cause apnea, coma, convulsions; dizziness, headache, weakness, irritability, insomnia; stomach upset, and if liquid: frostbite. Workers may be harmed from exposure to hydrogen sulfide. The level of exposure depends upon the dose, duration, and work being done.

Hydrogen sulfide is used in many industries. For example, it’s used to produce textiles. Some examples of workers at risk of being exposed to hydrogen sulfide include the following:

  • Factory workers in plants where rayon textiles are manufactured
  • Petroleum and natural gas workers involved in drilling and refining
  • Workers in wastewater treatment industries
  • Agricultural workers on farms with manure storage pits or landfills

NIOSH recommends that employers use Hierarchy of Controls to prevent injuries. If you work in an industry that uses hydrogen sulfide, please read chemical labels and the accompanying Safety Data Sheets for hazard information. Visit NIOSH’s page on Managing Chemical Safety in the Workplace to learn more about controlling chemical workplace exposures.

The following resources provide information about occupational exposure to hydrogen sulfide. Useful search terms for hydrogen sulfide include “hydrosulfuric acid,” “sewer gas,” and “sulfuretted hydrogen.”

NIOSH Chemical Resources

Related NIOSH Resources

Selected Publications

Number Title
01MI061, 01MI063 Two Individuals Overcome By Hydrogen Sulfide Gas While Cleaning a Farm Facility Water Well With 28% Liquid Muriatic Acid.
94MN057 Waste Hauling Service Worker Dies After He Collapsed In An Underground Manure Waste Pit.
94MN045 Farmer Asphyxiated in Manure Waste Pit.
92NJ020 Police Officer Drowns After Being Overcome by Hydrogen Sulfide While Attempting Rescue of Construction Worker
91CO074 Sanitation Worker Dies When Rescuing Co-worker From Underground Sewer Vault.
9228 Hog Farm Co-Owner and Employee Die of Hydrogen Sulfide Poisoning in Manure Pit–Minnesota.
8928 Two Maintenance Workers Die After Inhaling Hydrogen Sulfide in Manhole.
8946 Five Family Members Die After Entering Manure Waste Pit on Dairy Farm.

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