Toxicity of Cyanide in Smoke

The combination of toxic gases in smoke can be lethal to anyone trapped inside a burning building and forced to inhale this deadly mixture. Several studies have shown both carbon monoxide and cyanide, independently and in combination with each other, can be deadly to those trapped in burning buildings.

• A study conducted by the Paris Fire Brigade showed a direct relationship between blood cyanide concentration and occurrence of fire-related death, suggesting that cyanide contributed to many of the 43 fire-related deaths they studied.
• Another study of a 1991 prison fire, which killed 35 inmates in Argentina, suggests hydrogen cyanide generated by the rapid thermal decomposition of the polyurethane mattresses was the most likely cause of death for these victims. The researchers found the carboxyhemoglobin (the compound that is formed when inhaled carbon monoxide combines with hemoglobin) saturation values in the victims was considered within the nonlethal range, while the victims blood cyanide levels all exceeded the lethal range.
• Additional studies have shown that the combination of cyanide and carbon monoxide exposure in a structural and closed-space fire is frequent and potentially more dangerous than carbon monoxide alone.
• Finally, studies have shown inhaling even sublethal amounts of cyanide can be dangerous resulting in increased confusion and incapacitation. This can result in decreased time to escape, inability to escape at all, and an increase in the likelihood of burns.