Securing U.S. Radioactive Sources: Although the U.S. Government has Stepped up Efforts to Prevent Acts of Radiological Terrorism, Significant Gaps in Security Remain to be Filled‪.‬

The catastrophic attacks of September 11, 2001, and the anthrax mailings that took place shortly thereafter highlighted the nation's vulnerability to unconventional forms of terrorism. One type of threat that has recently received close attention from policymakers and the news media is the potential for attacks with radiological dispersal devices (RDDs). Such weapons, which include so-called dirty bombs, are designed to spread radioactive contamination, causing panic and disruption over a wide area. The number and diversity of radioactive sources pose a serious security challenge, and the United States has yet to take all the necessary steps to strengthen controls to match the heightened terrorist threat. Most people are aware of the danger of radioactive material associated with nuclear power, but the potential sources of material for an RDD include a large class of commercial radioactive sources used in medicine, industry, and scientific research. Of the millions of sources in use worldwide, only a small fraction, if maliciously employed in an RDD, are powerful enough to cause serious harm to human health. Yet this fraction still includes tens of thousands of sources of the type and quantity useful for a potent RDD. (See the sidebar for information on the types of potentially high-risk sources within the United States.)