Dirty bomb

A dirty bomb or radiological dispersal device (RDD) is a speculative radiological weapon that combines radioactive material with conventional explosives. The purpose of the weapon is to contaminate the area around the dispersal agent/conventional explosion with radioactive material, serving primarily as an area denial device against civilians. It is, however, not to be confused with a nuclear explosion, such as a fission bomb, which by releasing nuclear energy produces blast effects far in excess of what is achievable by the use of conventional explosives.

Though an RDD would be designed to disperse radioactive material over a large area, a bomb that uses conventional explosives and produces a blast wave would be far more lethal to people than the hazard posed by radioactive material that may be mixed with the explosive. At levels created from probable sources, not enough radiation would be present to cause severe illness or death. A test explosion and subsequent calculations done by the United States Department of Energy found that assuming nothing is done to clean up the affected area and everyone stays in the affected area for one year, the radiation exposure would be "fairly high" but not fatal. Recent analysis of the nuclear fallout from the Chernobyl disaster confirms this, showing that the effect on many people in the surrounding area, although not those in proximity, was almost negligible.

Dirty bomb in Alpha and Omega
Early one morning, terrorists exploded a dirty bomb at Tel Aviv's main bus terminal. Despite the early hour, many people were around when the heavy van speed up to the main entrance. Security guards at the station opened up with automatic fire but it was too late as the driver set off the explosives. It was later determined that the radioactive substance was Plutonium oxide. The Israelis spent some time decontaminating the area, first by spraying all surfaces in a ten block area with a sticky substance to prevent the winds from spreading radioactivity. This was peeled off and then the area was washed down with a water-based gel.