This case involves a man who was exposed to carbon monoxide while living in an apartment building in a major northeastern city. At the time of the incident in question, the man had been left alone in the apartment while his girlfriend went to work. When she returned, she found her boyfriend unconscious on the kitchen floor. The man was taken to the hospital by ambulance, where he was declared dead shortly after arrival. Subsequent lab testing revealed that the man had been killed by acute carbon monoxide poisoning. The source of the carbon dioxide was believed to be a furnace that had recently been installed by an HVAC company in the building’s basement, which was directly below the couple’s apartment.