Methemoglobinemia following fire exposure is largely unrecognized. Fire related morbidity and mortality are customarily attributed to thermal injury, associated trauma, and carbon monoxide poisoning. More recently, cyanide poisoning has been described from the inhalation of hydrogen cyanide liberated from of burning plastics (1). Symptoms of tissue hypoxia and cyanosis resulting from methemoglobinemia may be difficult to diagnose in the presence of thermal injury, cyanide and/or carbon monoxide poisoning. Relatively low levels of methemoglobin could complicate concomitant carbon monoxide poisoning by additive or synergistic effects on oxygen binding and delivery. We report 3 cases of significant methemoglobinemia (levels of 19, 12, and 12%) in survivors of a dwelling fire and review the literature with regard to this phenomenon.