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H2S: hydrogen sulfide

H2S (Hydrogen Sulfide) is an extremely toxic gas which can be fatal. H2S gas is found in large amounts in natural gas
petroleum. Workers have an increased risk of exposure when involved in the drilling of oil and gas from sour gas regions (as well as some unknown regions), working on older wells and during acid jobs.

Effects of H2S exposure:
• At 10 PPM, the gas becomes toxic to personnel
• At 300 PPM, a person’s smell is quickly deadened
• At 500 PPM, the gas strikes the respiratory mechanism in the brain causing a person’s breathing to stop and a loss of
consciousness within approximately 15 minutes
• At 700 PPM, a rapid loss of consciousness and death can occur
• At 1000 PPM, immediate unconsciousness and death occurs

How to protect workers:
• Written safety policies and procedures should be created and implemented to address H2S hazards and controls
• Employees should be provided with training on the subject specific to their work environment
• Although H2S as an odor of rotten eggs at lower concentrations, it is odorless at higher levels
• Appoint a qualified person to test (monitor) ambient conditions for H2S before the start of work


This article is provided solely as a reference tool to be used for information purposes only. The information in this article shall not be construed or interpreted as providing legal or any other advice. The information material does not amend the provisions of any insurance policy issued by CompSource Mutual. It is not a representation that coverage does or does not exist for any particular claim or loss under any such policy. Coverage depends on the facts and circumstances involved in the claim or loss, all applicable policy provisions, and any applicable law.

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