Honeywell - Model H450EN - Carbon Monoxide Alarm - Brochure

Carbon Monoxide (CO) is a highly poisonous gas which is released when fuels are burnt. It is invisible, has no smell and is therefore very difficult to detect with the human senses. The first warning symptoms that CO is present in the air are usually headaches and nausea. Under normal operating conditions, in a room where fuel-burning appliances are well maintained and correctly ventilated, the amount of Carbon Monoxide released into the room by the appliances is not dangerous.