Occupational fatality and persistent neurological sequelae after mass exposure to hydrogen sulfide

Exposure to hydrogen sulfide (H2S) has been associated with death as well as survival following coma with or without hypoxic brain damage. 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. Despite increased awareness of the potentially life-threatening consequences of exposure to H2S, significant poisoning continues to occur, even in workplaces where the hazards are well-known and can be avoided. 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. This approach could standardize and enhance our knowledge of, and ability to detect, the subtle but permanent alterations of central nervous system function that follow H2S exposure.