| Hazards summary | Hydrogen sulfide (H2S) occurs naturally in crude petroleum, natural gas, volcanic gases, and hot springs. It can also result from bacterial breakdown of organic matter. It is also produced by human and animal wastes. Bacteria found in your mouth and gastrointestinal tract produce hydrogen sulfide from bacteria decomposing materials that contain vegetable or animal proteins. Hydrogen sulfide can also result from industrial activities, such as food processing, coke ovens, kraft paper mills, tanneries, and petroleum refineries. Hydrogen sulfide is a flammable, colorless gas with a characteristic odor of rotten eggs. It is commonly known as hydrosulfuric acid, sewer gas, and stink damp. People can smell it at low levels.CNS injury is immediate and significant after exposure to hydrogen sulfide. At high concentrations, only a few breaths can lead to immediate loss of consciousness, coma, respiratory paralysis, seizures, and death. . . . Hydrogen sulfide is a mucous membrane and respiratory tract irritantpulmonary edema, which may be immediate or delayed, can occur after exposure to high concentrations. [ATSDR Medical Management] Like cyanide, causes cellular asphyxiationAlso a mucous membrane irritantIDLH = 100 ppmPulmonary edema at 300-500 ppmRapidly fatal at 600-800 ppm[Olson, p. 271] H2S is heavier than airit displaces air in confined spaces. 80 fatalities were recorded by OSHA from 1984-94. Prevent deaths by using H2S detection equipment, air-supplied respirators, and confined space safety training. [Fuller DC, Suruda AJ. J Occup Environ Med. 200042:939-942] Possible frostbite from contact with liquid[NIOSH] The following chemicals can release H2S when spilled in water: Sulfur chloridesPhosphorus pentasulfideand Sodium, Potassium, Calcium & Zinc hydrosulfite. [ERG 2016] Measuring thiosulfate in urine allows health care providers to identify nonfatal H2S exposure, allowing life-saving prevention opportunities. Measuring thiosulfate in blood is the preferred method to confirm death from H2S exposure. [PMID 24164756] See the Process, Toxic Gas from Spilling Chemical in Water. Hydrogen sulfide is fibrogenic to the lungs in the context of an acute inhalation exposure complicated by bronchiolitis obliterans.Thiols (or mercaptans, an older term) are a group of chemical compounds with structural similarity to alcohols, e.g., ethanethiol (C2H5SH) resembles ethanol (C2H5OH). Some thiols are used as warning gases. Their strong and repulsive odor can warn users of an explosive gas that is leaking into the air. [Hawley] See Benzenethiol, n-butyl mercaptan, methanethiol, ethanethiol and other thiols in this database. The thiols with higher vapor pressures can be acutely toxic in spill accidents causing respiratory irritation, coma, and death. The thiols can, like hydrogen sulfide, produce CNS injury and respiratory paralysis. [ACGIH] See Methyl mercaptan, Benzenethiol (Phenyl mercaptan), and 2-Methyl-2-heptanethiol all classified as TIH (Toxic Inhalation Hazard). [ERG 2016]. |
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