Carbon monoxide (CO) is a deadly, colorless, odorless, poisonous gas.
On average, about 170 people in the United States die every year from CO produced by non-automotive consumer products.
Because CO is odorless, colorless, and otherwise undetectable to the human senses, people may not know that they are being exposed.
CO alarms always have been and still are designed to alarm before potentially life-threatening levels of CO are reached. The safety standards for CO alarms have been continually improved and currently marketed CO alarms are not as susceptible to nuisance alarms as earlier models.