Fallout

Fallout, radioactive debris produced by the explosion of nuclear weapons. Local fallout rains down over an area up to about 50 mi (80 km) downwind of the explosion for several hours afterwards. The radiation produced by the fallout causes severe radiation sickness and possibly death to any people living within this area. More fallout rises into the lower atmosphere (the troposphere) and is washed down with rain over a wider area over the next few months. Still more rises even higher, into the stratosphere, where it may be blown around the globe for months or years before it descends to the ground. Some isotopes in fallout keep producing radiation for a long time and become absorbed by plants, animals, and human beings.

See also: Nuclear weapon; Radiation.