"After British physicists demonstrated the technical feasibility of nuclear explosive weapons, attention quickly turned to their development throughout the remainder of the war [World War II]. In 1946, the United States conducted the Operation Crossroads nuclear weapons tests at Bikini Atoll in the Marshall Islands. The widespread contamination of ships used in these tests gave dramatic evidence of the potential of so-called radiological warfare. In 1947, the Defense Department began creating panels of experts to study the offensive and defensive aspects of what it termed 'Rad War.' This led to an active test program, including releases of radiation into the atmosphere in the 1940s and 1950s. The results of these early experiments showed that while RDDs [Radiological Dispersal Devices] were not effective as battlefield weapons, such weapons could have a significant psychological effect. Yet, for the next four decades, there was little documented interest in developing radiological weapons. Recent concerns with an RDD threat center on both state and non-state actors. According to Western press reports in January 1991, Iraq claimed to have 'secret' or 'unusual' weapons that could kill tens of thousands of its foes. U.S. intelligence concluded that it was possible for Iraq to build a functioning RDD. An unclassified CIA [Central Intelligence Agency] report stated that Iraq could have obtained radioactive material from research reactors and that it could disperse this material using a conventional explosive. The report concluded that an Iraqi RDD would not be a 'militarily significant' weapon because it could not cause widespread radiation sickness, even if used against unprepared and unprotected civilians in a city. However, the report also concluded that any Iraqi use of an RDD would have a substantial psychological impact."
Strategic Forum No.136