3 mg/L) in 31 cases. For victims with cyanide levels above 3 mg/L the mean carboxyhemoglobin level was 62.5%. Cyanide poisoning is infrequent in fire fatalities, and when present it is associated with significant carboxyhemoglobinemia. Cyanide can be both produced and degraded in blood and tissue, making interpretation of blood levels difficult. In survivors of fire, detoxification of cyanide can occur without specific antidotes with the use of aggressive supportive care. Specific assay and treatment for cyanide poisoning is rarely necessary in the treatment of victims of smoke and fire.