Why is Hydrogen Sulfide listed in the Major Accident Hazard (MAH) category for Hydro Carbon operations?
H2S is identified as Major Accident Hazard (MAH) in Hydro carbon operations. Each day, many workers in the oil and Gas, petrochemical, construction, waste water, paper-pulp and other industries are exposed to hydrogen sulfide gas. Hydrogen Sulfide is a colorless, transparent gas with a characteristic of a rotten-egg odor at low concentrations and not detectable by odor at high concentrations. Hydrogen sulfide is the chemical compound with the formula H2S (chemical symbol).
It is highly flammable and toxic, even at low concentrations. HMIS (Hazardous Materials Identification System) and NFPA (National Fire Protection Association) gave H2S a flammability rating of 4, which is the highest rating. 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). 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.
H2S is very poisonous, corrosive.