Often called the silent killer, carbon monoxide is an invisible, odorless, colorless gas created when fuels (such as gasoline, wood, coal, natural gas, propane and oil) burn with inadequate amounts of oxygen, creating a condition known as incomplete combustion. In the case of home gas appliances, this can be caused by improper installation, poor maintenance, or other appliance misuse or failure. When incomplete combustion occurs in a home’s gas appliances, carbon monoxide is produced, and this can lead to carbon monoxide poisoning.