carbon monoxide (CO) [L, carbo + Gk, monos, single, oxys, sharp] , a colorless, odorless, poisonous gas produced by the combustion of carbon or organic fuels in a limited oxygen supply, as in the cylinders of an internal combustion engine or an improperly set oil or gas furnace. CO binds to hemoglobin approximately 210 times stronger than oxygen, preventing the formation of oxyhemoglobin and reducing the oxygen supply to the tissues. Prolonged exposure to high levels of CO results in asphyxiation.
