Significant increases in unossified sternebrae occurred at 800 ppm CS2 and reduction of fetal body weight at 400 and 800 ppm CS2. It is also a hazard in sewage treatment and manure-containment operations, construction in wetlands, pelt processing, certain types of pulp and paper production, and any situation in which organic material decays or inorganic sulphides exist under reducing conditions. H2S dissociates into free sulphide in the circulation. Sulphide binds to many macromolecules, among them cytochrome oxidase. Other effects may include mucosal irritation, which is associated at lower concentrations with a keratoconjunctivitis called 'gas eye' and at higher concentrations with risk of pulmonary oedema.
Treatment is currently empirical, with a combination of nitrite and hyperbaric oxygen preferred.
The treatment regimen is not ideal and carries some risk. The release of H2S at a beachfront construction site led to the emergency evaluation and treatment of 37 people, with six admissions and one death. At least one victim, who underwent extensive therapy with hyperbaric oxygen, developed persistent neurological sequelae. Recommended therapy includes nitrites, hyperbaric oxygen, and supportive care, but documentation of efficacy is lacking. Because patients with chronic neurological sequelae after acute H2S exposure continue to be reported, we suggest that any survivor of H2S poisoning who presents in coma or who manifests objectively verifiable evidence of neurotoxicity on physical examination or lab testing should undergo baseline and annual neurological and neuropsychological testing for at least five years.