How fires kill

Death caused by severe burns is only one fatal danger of fire fact, only about one-fourth of home fire victims die from arms. The rest die from inhaling smoke and poisonous gases or from lack of oxygen.
Smoke and poisonous gases can kill you long before the flames reach you. A sleeping person who inhales smoke and poisonous gases may never wake up, or may pass out as soon as he or she sits up to escape. Deadly gases-among them carbon monoxide-irritate the eyes and throat making escape difficult and cause you to breathe faster, thereby increasing your intake of other poisonous gases released by fire. Breathing superheated air, on the other hand, can cause rapid and severe lung damage.
Normally, the air we breathe is 21 percent oxygen. During a fire, that level drops rapidly. If it drops below 17 percent, people breathing the air will have difficulty thinking clearly and controlling their muscles. They may become irrational and uncoordinated, making escape more difficult. When the oxygen in the air drops into the 10 to 6 percent range, breathing stops. After four to six minutes without oxygen, brain death occurs.