The June 18th arrest of two men for allegedly plotting to build a bizarre yet potentially deadly radiological device once again highlights the potential nexus of non-state actors with so-called weapons of mass destruction (WMD). However, much like this year’s troika of ricin-laced letters addressed to government facilities (including one to the CIA) and public officials (all three incidents targeted President Obama at his White House address), this most recent plot reveals the historical rarity and non-lethality of non-state actors and their behaviors with radiological weapons and agents. While the potential for catastrophe posed by terrorist use of chemical, biological, radiological, and nuclear (CBRN) weapons deserves ongoing and serious attention, recent events remind us how public apprehension is sometimes founded more in fear than reality; indeed, reactions based on fear are capable of far more disruption than the physical reality of the event itself. The role of science-based organizations such as the Federation of American Scientists is to educate the public about the real risks.
Of the CBRN threats, the nuclear threat is undoubtedly truly catastrophic because a nuclear weapon can cause massive destruction, but obtaining a nuclear weapon or the fissile material to make such a weapon is very hard to do. In comparison, radiological sources are far more common, but most of them would cause little or no harm to human health if dispersed by a radiological weapon because there is not enough radioactive material contained in the vast majority of each of these sources. And even those radiological sources containing highly radioactive materials would pose great difficulties for terrorists to use because they would hazard exposing themselves to lethal ionizing radiation. These latter issues, and others outlined below, are very relevant to the recent radiological plot.