Usually CO is produced while burning fuels like gasoline, coal, wood, charcoal, kerosene, natural gas, propane and heating oil, as well as almost any other combustible material such as tobacco, fibers and paper. There is an even greater risk of CO accumulation if your home or building is tightly sealed and not properly ventilated. While smoke inhalation from fires is a common cause of CO poisoning, cigarette smoke and vehicle exhaust are the most common sources of CO exposure.

If your home or building has an attached or tucked-under garage, air and any pollutants in the air may flow from the garage into the structure. So, if you leave a car or other combustion engine running inside the garage, or if an air intake duct is located next to a heavily traveled road or near a loading dock, CO can accumulate.

Any fuel-burning equipment or appliances, including wood stoves, fireplaces, space heaters, barbecue grills, furnaces, water heaters, boilers and ranges, have the potential to produce CO. When natural gas equipment is properly operated and maintained, it usually will not produce CO.