A carbon monoxide detector or CO detector is a device that detects the presence of the carbon monoxide (CO) in order to prevent carbon monoxide poisoning. CO is a colorless and odorless compound produced by incomplete combustion that is lethal at high concentrations. If a high concentration of CO is detected, the device sounds an alarm, giving people in the area a chance to ventilate the area or safely leave the building.
Carbon monoxide is produced from incomplete combustion. In the home CO can be formed, for example, by open flames, space heaters, water heaters, blocked chimneys or running a car inside a garage.