Fire is an integral part of our everyday life, and smoke is one of its products. There have always been efforts to control fire and use it for constructive purposes, but even then, accidental fires do occur and fire continues to cause loss of lives and property.
Uncontrolled fires threaten homes, factories, and transportation systems.
The specter of fire in the air is a pilot's recurrent nightmare, carried over from the early days of fabric covered aircraft, when the time between ignition and loss of the aircraft could be measured in relatively few minutes. Modern aircraft benefit from flame retardant materials and improved fire extinguishing systems to such an extent that in-flight fires are rare occurrences. However, survivable crashes followed by fire happen, primarily from fuel spills around the downed aircraft. In the confined environment of an aircraft cabin, the presence of smoke automatically indicates the existence of an emergency situation. Extinguishment of fires obviously has first priority, but smoke inhalation should be recognized as a very real danger while this is being accomplished.