Not all suicide victims are this considerate...
Chemical Overview
Hydrogen sulfide (HS) -- H2S -- is a colorless, flammable gas that is heavier than air and has the characteristic odor of rotten eggs at concentrations as low as 0.5 ppm. HS poisoning is rare because its odor alerts potential victims to the danger. However, concentrations greater than 100 ppm can cause olfactory fatigue and mislead individuals that the exposure risk has resolved. Toxic exposures most frequently occur in small closed spaces into which the victim enters unaware of the toxic build-up of the gas.
HS poisoning is mainly encountered within the petroleum, viscose rayon, rubber, food processing, tanning and mining industries as well as in coke ovens and kraft paper mills. In nature, HS is the produced by the organic decomposition of sulfur compounds in sewers, barns, ships’ holds, and sulfur springs. The major route of toxicity for HS is by inhalation.
At lower doses, local irritant effects predominate. At higher exposures, cellular respiration may cease as HS forms a complex bond to the iron ion in mitochondrial cytochrome oxidase, arresting aerobic metabolism in an effect similar to cyanide toxicity and affecting all organs, particularly the nervous system.
Sudden death can occur at concentrations >700 ppm. HS may also be absorbed from the gastrointestinal (GI) tract and skin, although these are rarely seen. GI absorption is typically seen in victims who ingest it after collapsing from the “knockdown” effect of an inhalation exposure.
The Occupational Safety and Health Administration (OSHA) has established an acceptable ceiling concentration of 20 ppm in the workplace, with a maximum level of 50 ppm allowed for 10 minutes if no other measurable exposure occurs. The National Institute of Occupational Safety and Health (NIOSH) recommends a maximum exposure level of 10 ppm.
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David Walker
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Mike Schlags (Captain Busy) Retd
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Bill Carlisle
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