Hydrogen sulfide is a colorless, noxious gas with the distinctive smell of rotten eggs. This compound is a powerful reducing agent that is encountered in a number of industrial processes. When hydrogen sulfide is present, it exposes workers to the potentially lethal effects of the rapid hypoxemia that results from exposure to this agent. The "warning sign" is the characteristic smell of rotten eggs; this smell should alert anyone in the area that a potentially serious risk exists. The immediate removal of the victim and administration of high-flow oxygen is essential. Neurologic sequelae may require anticonvulsants and care must be exercised to observe for cardiac, hepatic, and renal insufficiency. Depending on the concentration, hydrogen sulfide can rapidly overcome a potential victim.