"Radiological dispersal devices (RDDs) are devices, other than a nuclear explosives device, designed to disseminate radioactive material in order to cause destruction, damage, area denial, or injury. "(1) RDDs are designed to disperse radiation and/or contamination. One design, called "dirty bombs," uses explosives to disperse radioactive contamination. A dirty bomb typically generates its immediate casualties from the direct effects of the conventional explosion (i.e., blast injuries and trauma). The main purpose of a dirty bomb is to frighten people by contaminating their environment with radioactive materials and threatening large numbers of people with exposure. Their use may also result in area denial and costly cleanup or decontamination. "(2) By scattering the radiological material, the RDD may create a large area of radiological contamination. The actual dose-rate will be dependent upon the type and quantity of radioactive material spread over the area. This may not be uniformly distributed. As an area denial weapon, an RDD can generate significant public fear and economic impact since the area affected may involve loss of use during a lengthy and costly decontamination process. The contaminated area poses a danger to individuals by external or internal radiological contamination. External contamination on individuals can usually be removed by surface cleaning, and by removing contaminated clothing. Internal contamination is much more dangerous and occurs when contaminants are ingested and/or inhaled and concentrate in tissue. This may result in prolonged, high intensity local radiation exposure". (JCS/DOD, CBRNE CM, 2006, pp. I-7 and I-8)