Environmental, Health and Safety Services

What are some effects of hydrogen sulfde exposure?

Hydrogen sulfide is a colorless gas with a rotten egg like odor.  It can appear naturally or as a byproduct of decomposition.  Hydrogen sulfide is considered a highly toxic gas because it reacts with enzymes in the blood stream and can inhibit cell respiration.  Although hydrogen sulfide is easily detected by sense of smell, it is a desensitizer at 100 ppm after 2-5 minutes of exposure.  Common signs and symptoms include:

  • At 100 ppm, coughing and eye irritation.
  • At 200-300 ppm, eye inflammation and respiratory tract irritation after 1 hour.
  • At 500-700 ppm, loss of consciousness, stopping or pausing of respiration, and death.
  • At 1000-2000 ppm, immediate unconsciousness and death within a few minutes.

Continuous air monitoring and ventilation are the best means of prevention.