Abstract: Employees #1 through #5 were working during a holiday. One of them requested that the heat be turned up, which required the employer to change damper settings to switch from air conditioning to heating. The employer thought he smelled smoke and returned to the basement. When he saw smoke coming from the exit duct to the chimney, he shut down the system and called Nutmeg Heating, who came and fixed the problem. The employer then left the office, but returned several hours later to find fire trucks arriving at the building. He was told by the fire department that some employees had been take to the hospital suffering from carbon monoxide poisoning. Employees #1 through #3 were hospitalized; Employees #4 and #5 were treated and released. The building was immediately evacuated, and the fire department shut down all the systems in the building with any connection to the gas furnace and water heater.