Peter B. Lyons, Commissioner Nuclear Regulatory Commission before the Midyear Meeting of the Health Physics Society, G. William Morgan Lecture, in Scottsdale, Arizona on January 23, 2006. "The traditional focus of the regulation of radioactive sources was the protection of workers and the public from their misuse or from accidents. Security measures were also a concern, but with the principal aim of preventing petty theft or accidental loss. The events of September 11, 2001, however, changed the way in which we must think about sources. Our perspective must now encompass the possible malevolent use of radioactive materials in weapons of terror. As a result, past practices must be modified to reflect the threat environment. One of our concerns, of course, is that a high-risk radioactive source might be combined with conventional explosives and used in a radiological dispersal device (or RDD). Now as far as I know, RDDs are not part of the military arsenal of any country for the simple reason that they are not very good weapons. Our analyses verify that such devices would not cause large numbers of fatalities. However, RDDs might nonetheless meet a terrorists objectives to cause panic and potential environmental contamination that could seriously disrupt normal activities in the affected area or cause significant economic impact. Thus, we must protect the public from malevolent use of high-risk radioactive sources."
U.S. Nuclear Regulatory Commission: http://www.nrc.gov/