Carbon monoxide (CO) is a colorless, odorless and tasteless gas. It’s made by incomplete fuel combustion usually caused by not enough oxygen. In your home, appliances that use natural gas, charcoal, wood or kerosene are at risk. Especially if they are not running properly or have been installed wrong.
Vehicle exhaust fumes from nearby garages, as well as malfunctioning fireplaces could also be a carbon monoxide source. CO is poisonous to the body and is fatal at high levels or with prolonged exposure.