Radiation is energy that can travel through the air and even through some material. Earth is continually bombarded with radiation from the sun. It is what allows life to exist on Earth. Too much radiation (especially certain types of radiation) can be hazardous. If you have ever had sunburn you have been affected by too much radiation. You also get exposed to radiation if you watch television, use a microwave oven or have an x-ray. Much of the radiation we are exposed to everyday is normal and is not  harmful. Exposure to radiation from an accident at a nuclear power plant is one possible source of a radiological emergency. Safety precautions at modern nuclear power plants make that possibility extremely remote.  However, accidents are possible.  The best way to minimize exposure is to get away from the source of radiation, stay away until levels are reduced and/or shield yourself by taking shelter.

Ever since the development of the atomic bomb we have lived with the constant possibility that we will be exposed to radiation form a nuclear attack. During the cold war people were very concerned about a nuclear attack. Since 9/11 and the attention given to terrorism, the specter of a nuclear attack has once again gained attention.