Carbon monoxide (CO) is a clear, odorless and tasteless gas. It’s made by partial fuel combustion often caused by not enough oxygen. In your residence, appliances that rely on natural gas, charcoal, wood or kerosene are susceptible. Especially if they are not running accurately or have been installed wrong.
Vehicle exhaust fumes from neighboring garages, as well as fireplaces that aren’t working right could also produce carbon monoxide. CO is dangerous to the body and is deadly at heightened levels or with prolonged exposure.