The nuclear threat consists of the potential for an intentional or accidental initiation of a global exchange of ionizing radiation. This includes a nuclear explosion, the subsequent radioactive fallout and the long-term effects of such an exchange on health and the environment. This issue is of special concern because of the long-range capability of current nuclear weapons, including intercontinental ballistic missiles (ICBMs) and submarine-launched ballistic missiles (SLBMs).
The world has used nuclear weapons twice in war, in the 1945 atomic bombings of Hiroshima and Nagas, which killed between 150,000 and 246,000 people. Since then, a number of nations have developed nuclear weapons and a few others may be close to possessing them. In general, the more powerful a weapon is, the larger its destructive radius and the more people it will kill or injure.
Nuclear weapons can be exploded on the ground or mounted on a missile and launched into the air to reach targets anywhere in the world. Most nations now possess a large arsenal of both short-range and long-range missiles capable of carrying nuclear warheads to their target.
A nuclear detonation will cause a sudden bright light that can blind people for a few seconds. Then, a sustained roar of sound accompanies the explosion. The explosion also releases a plume of radioactive particles called “fallout.” These are usually small, sandy-looking particles that will move quickly to the ground and cover a wide area. Fallout can contain dangerous levels of radiation that can kill you if they come into contact with your skin or if they are inhaled. There are three ways to limit your exposure: shielding, distance and time. The best way to minimize your risk is to seek shelter in a basement, underground parking garage or the center of a large modern brick or concrete building.