The major sources of benzene exposure are tobacco smoke, automobile service stations, exhaust from motor vehicles, and industrial emissions. Vapors (or gases) from products that contain benzene, such as glues, paints, furniture wax, and detergents, can also be a source of exposure. During fires, polyurethane foams burn rapidly and produce dense smoke, toxic gases and intense heat. Carbon monoxide is most common, but smoke also contains benzene, toluene, nitrogen oxides and hydrogen cyanide.