Exposure to Hydrogen sulfide's mechanism of toxicity is similar to that of cyanide inhibition of the cytochrome oxidase system resulting in cellular asphyxia. Manifestations of H2S toxicity may be secondary to acute or chronic exposure. H2S possesses both topical irritating effects and systemic toxicity. The irritative and inflammatory effects of H2S on mucous membranes predominate at exposures to concentrations between 100 and 500 ppm. The primary targets of H2S is the central nervous and respiratory systems.
Metabolic acidosis can occur secondary to anaerobic metabolism.
Hydrogen sulfide is also a mucous membrane and respiratory tract irritant. Low level of H2S result in irritation of the eyes, nose and throat. Moderate levels can cause headache, dizziness, vomiting, as well as cough and difficulty in breathing. High levels can cause shock, convulsions, coma and death. Injured by chronic exposure to H2S experience respiratory problems, neurological dysfunction, such as amnesia, tremor, disturbance of equilibrium, including severe fatigue, headache, and skin problems, more serious brain damage, as well as persistent ill-health following exposure.