Introduction

Nuclear weapons can be categorized as two types: fissile, or explosive, and radiological. Radiological weapons are the more probable choice of terrorists. These weapons emit radiation alone, which destroys individual cells. By killing fast-replicating blood-forming cells as found in bone marrow and cells that line the intestinal tract, "radiation poisoning" can cause untreated victims to dehydrate and bleed to death. Unlike chemical weapons, which degrade once they come in contact with oxygen and moisture in the air, radiological weapons can continue to inflict damage for years and maintain their lethal effect even if they are dispersed with an explosive.

In the case of a radiological incident, the onset of symptoms requires days to weeks and there typically will be no characteristic signatures. Radiological materials are not recognizable by the senses and are colorless and odorless.

Specialized equipment is required to determine the size of the effected area and if the level of radioactivity presents an immediate or long-term health hazard. Because of the delayed onset of symptoms in a radiological incident, the affected area may be greater as a result of the movement of contaminated people.

In this section, we discuss three of the more often invoked threats: dirty bombs, nuclear weapons and sabotage of a nuclear power plant.