Abstract: After his shift was over at 3:30 PM on January 17, 1997, a preparation cook supervisor for a restaurant apparently spent sometime in the bar and then went to the mechanical room to sleep. The 3.0-meter by 3.4-meter room was located in a corner of the basement and contained two gas water heaters. On January 19, 1997, at 12:30 AM, the employee was found dead in the mechanical room. He had died of carbon monoxide poisoning. One water heater had malfunctioned and was producing excessive carbon monoxide. The duct at the wall connection to the outside exhaust was corroded through. The fire department and gas utility measured carbon monoxide at 800 parts per million with the room closed after water heaters had been running for 20 to 30 minutes with a constant flow of water. They measured carbon monoxide at 8000 parts per million in the heater's flue gas.