In this article, radiological weapons are referred to as radiological dispersal devices (RDDs). The author first discusses nuclear material, since this knowledge serves a better understanding of the construction of nuclear weapons and RDDs. Radioactive materials such as those used by industry or the medical field, if obtained in sufficient quantities, could be used in an RDD. The typical smoke detector contains some radioactive materials, although it would take an unprecedented number of them to construct an RDD. The main concern with the RDD threat would not necessarily involve death and destruction, but rather the creation of an inaccessible area due to contamination. An RDD is a conventional explosive device surrounded by radioactive materials. The technology behind these devices is no more difficult than building a pipe bomb. The radioactive material does not have to be that dangerous for the RDD to prove effective. The detonation of a RDD's conventional explosive materials does not necessarily have to cover a widespread area in order to cause great damage. The intent of the explosion is simply to disseminate radioactive materials. RDDs are an ideal weapon for terrorists. The psychological and economic impact of an RDD incident would most likely be devastating. The material used in a RDD determines the type of radiological contamination that occurs. This article discusses the primary types of radioactive contamination, radiological effects on humans, and decontamination. In discussing training for responding to such an attack, the author advises that every person who may possibly be involved in responding to a radiological incident should receive training in what needs to be done and how to do it. 4 references