Carbon monoxide (CO) is an invisible, odorless and tasteless gas. It’s made by incomplete fuel combustion often caused by not enough oxygen. In your residence, appliances that need natural gas, charcoal, wood or kerosene are susceptible. Especially if they are not running correctly or have been installed improperly.
Vehicle exhaust fumes from nearby garages, as well as malfunctioning fireplaces may also be a carbon monoxide source. CO is poisonous to the body and is lethal at high levels or with extended exposure.