Carbon monoxide (CO) is a clear, odorless and tasteless gas. It’s made by partial fuel combustion frequently caused by not enough oxygen. In your residence, appliances that consume natural gas, charcoal, wood or kerosene are at risk. Especially if they are not operating correctly or have been installed wrong.
Vehicle exhaust fumes from nearby garages, as well as poorly operating fireplaces may also create carbon monoxide. CO is dangerous to the body and is fatal at high levels or with extended exposure.