Carbon monoxide (CO) is a colorless, odorless and tasteless gas. It’s made by partial fuel combustion usually caused by insufficient oxygen. In your house, appliances that need natural gas, charcoal, wood or kerosene are susceptible. Especially if they are not running accurately or have been installed improperly.
Vehicle exhaust fumes from attached garages, as well as malfunctioning fireplaces may also create carbon monoxide. CO is poisonous to the body and is lethal at high levels or with prolonged exposure.