According to the National Fire Protection Association (NFPA), fire deaths due to smoke inhalation outnumber deaths due to burns by a 2-to-1 margin if death certificates from 2002 are used, and by 3-to-1 if death certificates prior to 1999 are used. It is also estimated that smoke inhalation is the primary cause of death in 60% to 80% of burn victims each year. Firefighters certainly are not immune to the danger (according to the NFPA, 2,890 firefighters were injured from smoke inhalation in 2003), often thrusting themselves into the hazard.
By definition, inhalation injury is the aspiration of superheated gases, steam, hot liquids, or noxious products of incomplete combustion that cause thermal or chemical injury to the airways and lungs. The combustion of all natural and manmade products results in the production of various chemicals, including hydrogen cyanide, aldehydes, hydrochloric acid, and acrolein, which produce the changes in the airway and lungs that are characteristic of inhalation injury. The injury can occur above or below the vocal cords, or in both locations at once. Injuries above the vocal cords are typically caused by inhaled heat, while those below the cords are usually caused by toxins and particulate matter. Because dry heat does not easily penetrate as far as the lower respiratory tract, true thermal damage of the lungs is rare.