Deadly Combination of Formic and Sulfuric Acid: 2 Cases of Carbon Monoxide Intoxication

Carbon monoxide (CO) poisoning is associated with high morbidity and mortality rates. Although accidental inhalation is the most common cause, suicide through CO from a mixture of formic and sulfuric acids is extremely rare and poses unique risks to first responders.

Two male individuals died in their vehicles after mixing formic and sulfuric acid to generate CO. Both cases showed characteristic cherry-red or pink livor mortis and high postmortem carboxyhemoglobin levels (73% and 85%, respectively). In both scenes, labeled acid containers and enclosed spaces were present, with 1 case noting an unusual odor.

Chemically induced CO poisoning, although rare, requires heightened awareness among first responders because of the danger of undetected exposure. Key indicators include unusual livor mortis, enclosed or taped-off spaces, chemical smells, and the presence of acid containers. Postmortem toxicology is crucial for confirming a diagnosis and understanding the cause of death.