hydrogen sulfide poisoning, poisoning by excessive exposure to hydrogen sulfide gas, seen primarily in those who work with petroleum or petrochemicals. The gas is a potent inhibitor of cytochrome-c oxidase, and poisoning is characterized by metabolic acidosis and anoxia. Severe cases may result in coma with death from respiratory paralysis. Treatments include immediate inhalation of amyl nitrate, injections of sodium nitrate, inhalation of oxygen, administration of bronchodilators, and, in severe cases, hyperbaric oxygen therapy.