Hydrogen sulfide (H2S) is an important cause of occupational intoxication. It acts just like cyanide, inhibiting cytochrome oxidase and causing cellular anoxia.
Sources of exposure include:
(1) sewer, manure pit
(2) gas and petroleum industry
(3) volcanoes, sulfur springs, mining
(4) rubber and chemical industry
(5) decomposing vegetable, fish or other biological material
Clinical features:
(1) smell of rotten eggs (sensitive at low levels but unreliable at higher levels due to respiratory fatigue)
(2) conjunctivitis, photophobia, keratoconjunctivitis, corneal ulceration
(3) irritation of mucous membranes (pharyngitis, rhinitis, bronchitis)
(4) chemical pneumonitis
(5) pulmonary edema and respiratory paralysis
(6) sudden loss of consciousness and coma (knockdown)
(7) convulsions
(8) sudden death
Air Concentration in Parts per Million (ppm) |
Clinical Finding |
0.1 - 0.2 ppm |
detectable odor |
50 ppm |
conjunctivitis, pharyngitis |
100 - 150 ppm |
olfactory fatigue |
250 ppm |
pulmonary edema |
> 700 ppm |
collapse, coma, sudden death |
Laboratory findings:
(1) elevated hydrogen sulfide in urine and blood
(2) elevated thiosulfate (major metabolite) in urine and blood
(3) high levels of hydrogen sulfide in an air sample
Findings at autopsy or surgery:
(1) coins or metal objects blackened
(2) tissue with smell of rotten eggs
(3) greenish discoloration to tissues
Specialty: Toxicology, Emergency Medicine, Critical Care
ICD-10: ,