Carbon monoxide (CO) is a clear, odorless and tasteless gas. It’s produced by partial 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 properly or have been installed improperly.
Vehicle exhaust fumes from neighboring garages, as well as poorly operating fireplaces can also be a carbon monoxide source. CO is poisonous to the body and is lethal at increased levels or with long exposure.