Silent Combustion, Fatal Consequences: An Autopsy-Based Case Report of Carbon Monoxide Poisoning from a Smoldering Mattress in an Enclosed Room

Carbon monoxide (CO) is a colorless, odorless gas produced by incomplete combustion and a common cause of accidental fire-related deaths. We report a 35-year-old man who, after consuming alcohol and smoking, slept in a closed, air-conditioned room and was found unresponsive the next morning with a smoldering mattress. Autopsy showed soot around the nostrils and in the larynx, trachea and bronchi, a minor burn over the lower limbs, and cherry-red discoloration of tissues and organs. Postmortem blood showed a carboxyhemoglobin (COHb) saturation of 56%. The cause of death was opined as asphyxia due to carbon monoxide poisoning, and the manner was accidental.