Fallout from nuclear weapons tests in Nevada contaminated the entire U.S.

Following a large nuclear war, enormous fires created by nuclear explosions in cities cause 150 million tons of smoke to be lofted high above cloud level, into the stratosphere. The smoke quickly spreads around the world and forms a dense smoke layer which will remain in the stratosphere for many years and act to block sunlight from reaching the surface of the Earth.

Following an India-Pakistan nuclear war, enormous fires created by nuclear explosions in cities cause 5 million tons of smoke to be lofted high above the cloud level, into the stratosphere. The smoke quickly spreads around the world and forms a dense smoke layer which will remain in the stratosphere for many years and act to block sunlight from reaching the surface of the Earth.