Carbon Monoxide
Carbon monoxide is a tasteless, odorless gas that is impossible to detect without a monitoring device. It is produced in many ways with the most common way being incomplete fuel combustion during heating and cooking. Combustion engines found in automobiles, snow blowers and lawnmowers create carbon monoxide while in use. Blocked chimneys, flues, or a damaged furnace can also allow carbon monoxide gas to enter your home. This colorless, odorless gas that is a byproduct of gas fired appliances throughout your home must be monitored for.
The most common type of carbon monoxide alarms plug into your wall outlets and have a battery backup. Interconnected combination alarms are available to integrate into your already existing smoke alarm system.
Just like smoke alarms, you should have a carbon monoxide(CO) alarm on every level of your home and within ten feet of sleeping areas, with interconnected alarms being optimal for alerting the entire household.