Carbon monoxide (CO) is a colorless, odorless and tasteless gas. It’s made by partial fuel combustion frequently caused by not enough oxygen. In your home, appliances that rely on natural gas, charcoal, wood or kerosene are susceptible. Especially if they are not running correctly or have been installed incorrectly.
Vehicle exhaust fumes from attached garages, as well as fireplaces that aren’t working right could also be a carbon monoxide source. CO is poisonous to the body and is lethal at high levels or with long exposure.