Wood'nCoal wrote: Supposedly an improperly adjusted burner (yellow flame instead of blue) will produce CO.
Winter before last on the local news was a 10 or 12 unit apartment house that was evacuated because of CO from a propane boiler. Darn lucky no one was killed. The unit had just been serviced (by an out of state company, weird) and somehow the exhaust pipe was not put back in properly. It leaked around the chimney & caused the people in the units close to the chimney to get sick. A friend stopped by to visit one of the tenants and noticed they didn't look well. The visitor happened to be a trained med-tec and was familiar with CO symptoms. They called 911 & vacated. When the fire department got there they discovered it was not that one unit, there were several people in 4 or 5 units that had headaches & nausea. Lucky, very lucky that no one was killed. Since then they've started enforcing CO detectors installed by landlords.