The notion of terrorist organizations using nuclear weapons (especially very small ones, such as suitcase nukes) has been a threat in American rhetoric and culture. It is plausible that terrorists could acquire a nuclear weapon.In physics, radiation is a process in which energetic particles or energy or waves travel through a medium or space. There are two distinct types of radiation; ionizing and non-ionizing.
The term dirty bomb refers to a speculative radiological weapon which combines radioactive material with conventional explosives. Though a radiological dispersal device (RDD) would be designed to disperse radioactive material over a large area, a bomb that uses conventional explosives would likely have more immediate lethal effect than the radioactive material. At levels created from most 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 Chernobyl disaster fallout confirms this, showing that the effect on many people in the surrounding area, although not those in close proximity, was almost negligible.
Since a dirty bomb is unlikely to cause many deaths, many do not consider this to be a weapon of mass destruction. Its purpose would presumably be to create psychological, not physical, harm through ignorance, mass panic, and terror. For this reason dirty bombs are sometimes called "weapons of mass disruption".
CDC has a key role in protecting the public's health in an emergency involving the release of radiation that could harm people's health. This site provides information to help people protect themselves during and after such an event. It also provides information for professionals involved in planning for and responding to this type of emergency.