Blue ice in the context of aviation is the frozen material formed by leaks in commercial aircraft lavatory waste tanks, a mixture of human waste and liquid disinfectant that freezes at high altitude. The name comes from the blue color of the disinfectant, and is a sardonic reference to the Blue Ice line of products used for cooling ice chests and similar applications.
Airlines are not allowed to dump their waste tanks in mid-flight, and pilots have no mechanism by which to do so; however, leaks can occur. There were at least 27 documented incidents of blue ice impacts in the United States between 1979 and 2003.These incidents typically happen under airport landing paths as the mass warms sufficiently to detach from the plane during its descent. A rare incident of falling blue ice causing damage to the roof of a home was reported on October 20, 2006 in Chino, California.
On January 28, 2007 at the Timberlanes subdivision in Tampa, Florida, under the approach path to Tampa International Airport, a red Mustang automobile owned by Andres Javaze was struck by a large block of ice estimated at 50 pounds which crushed the rear of the vehicle. A neighbor named Raymond Rodriguez reported hearing a whistling or whizzing noise as the ice fell from the sky before impact and watched as it smashed the vehicle. However, the chunk of ice was not blue and is not thought to have fallen from an airplane. The incident is being investigated by the FAA.
Blue ice became known to many people from the last 2003 episode of the HBO series Six Feet Under, in which a foot-sized chunk drops on an innocent bystander. It is also the title of a 1992 film where Michael Caine's character describes the concept of blue ice,and it also describe on the tv show MANswers .