Exposure to Hydrogen Sulfide
Hydrogen Sulfide (H2S), or sour gas, is a highly toxic, colorless gas. It is a very insidious industrial hazard for two reasons:
- unreliability of odor as a warning, and
- sudden onset of incapacitation.
Hydrogen Sulfide H2S
Hydrogen sulfide has been identified by NIOSH as a leading cause of sudden workplace death. At concentrations up to 30 parts per million (ppm), it has an odor of rotten eggs. However, at more deadly concentrations (100 ppm), hydrogen sulfide rapidly fatigues the olfactory nerves. A person may momentarily smell the gas but think little of it when the odor is no longer detectable. If exposure is sufficiently, intense, unconsciousness and respiratory failure may occur without warning symptoms. The gas is 1.2 times denser than air, and at high concentrations will tend to accumulate in low spots. Mixed with air in concentrations of 4.3-45.5%, hydrogen sulfide is explosive. It may also burn with the production of toxic sulfur dioxide.
Knowledge Check Choose the best answer for the question.
7-4. Why are higher concentrations of hydrogen sulfide more "insidious" than lower concentrations?
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