Burning fuels, including gas, wood, propane or charcoal, make carbon monoxide. Appliances and engines that aren't well vented can cause the gas to build up to dangerous levels. A tightly enclosed space makes the buildup worse.

CO is found in fumes produced any time you burn fuel in cars or trucks, small engines, stoves, lanterns, grills, fireplaces, gas ranges, or furnaces. CO can build up indoors and poison people and animals who breathe it. However, you can reduce your risk of CO poisoning with a few small steps.

Carbon monoxide is an odorless, tasteless, poisonous gas that forms when carbons from fuels burn incompletely. It is lighter than air and released both naturally, such as from forest fires and volcanic eruptions, and through man-made processes.

Carbon Monoxide (CO) is an invisible, odorless, colorless gas created when fuels such as gasoline, wood, coal, natural gas, propane, oil, and methane burn incompletely. In the home, heating and cooking equipment that burn fuel are possible sources of Carbon Monoxide. Vehicles or generators running in an attached garage can also produce dangerous levels of Carbon Monoxide.