Fan death

Fan death (Korean: 선풍기 사망설) is a widely-held belief in Korea that leaving an electric fan on overnight will kill a person. However, no people are known to have been killed by this.
Supposed cause of death.
The supposed cause of death is often said to be carbon monoxide poisoning, although this is impossible because an electric motor does not create carbon monoxide. Another supposed cause is asphyxiation, which is also impossible because a fan does not remove any air from a room. Hypothermia is also said to be the cause, although it too is impossible because a fan does not lower the temperature of the body enough to cause hypothermia.