Radiation exposure is discussed in detail elsewhere. Mass casualties due to radiation can result from the detonation of a nuclear device. A nuclear detonation not only creates a large burst of direct radiation but will also cause numerous blast and burn injuries and disperse radioactive material widely (termed fallout). Radioactive material can also be dispersed by packing it around a conventional explosive that is then detonated. Such a weapon is sometimes called a dirty bomb. People may also be exposed to radiation from a concealed source (for example, a container of radioactive material hidden under a subway seat). Doctors determine whether people have been exposed (irradiated), contaminated by radioactive dust and debris, or both. If contamination has occurred, doctors put people through decontamination measures.
(See also Overview of Incidents Involving Mass-Casualty Weapons.)