Unlike a "dirty bomb" which disperses radioactive material using conventional explosives, a nuclear attack is the use of a device that produces a nuclear explosion. A nuclear explosion is caused by an uncontrolled chain reaction that splits atomic nuclei (fission) to produce an intense wave of heat, light, air pressure, and radiation, followed by the production and release of radioactive particles. For ground blasts, these radioactive particles are drawn up into a "mushroom cloud" with dust and debris, producing fallout that can expose people at great distances to radiation.
The U.S. Department of Homeland Security and The National Academies teamed up in 2003 to produce fact sheets on chemical, biological, radiological, and nuclear attacks designed to help better prepare the media for the types of threats facing the nation.
Each fact sheet provides clear, concise information to the media and the public on the characteristics, dangers, and consequences associated with various types of attacks. Each fact sheet has been through a rigorous peer review process evaluated by independent members of the National Academies, many of whom are recognized as the nation's foremost experts in their field.