Smoke is made up of small particles of carbon in hot air and gases. The particles are covered with organic chemicals and smoke may also contain carbon monoxide and acids. When smoke is inhaled, the effects on breathing may be immediate or delayed, depending upon the density of smoke and its composition. Laryngeal stridor (obstruction of the LARYNX), lack of oxygen and PULMONARY OEDEMA are life-threatening symptoms that require urgent treatment. Immediate removal of the victim from the smoke is imperative, as is the administration of oxygen. The victim may require admission to an intensive-care unit.