Scientists urge U.S. to stop using caesium-137, a dirty bomb ingredient

Published 22 February 2008

About 1,300 machines at U.S. hospitals and universities used for irradiating blood for transplant patients and other purposes contain caesium-137; individuals or groups eager to detonate a dirty bomb in a U.S. city could steal this caesium chloride and combine it with conventional explosives such as dynamite to produce a dirty bomb or radiological dispersal device

Radioactive caesium chloride used in medical and research equipment can be used as a deadly ingredient in a dirty bomb and U.S. leaders should try to curb its use, the U.S. National Research Council (NRC) said on Wednesday in a report commissioned by Congress. About 1,300 machines at U.S. hospitals and universities used for irradiating blood for transplant patients and other purposes contain caesium-137 in the form of caesium chloride stored in stainless steel capsules, said the council, which is part of the National Academy of Sciences and provides advice to U.S. policymakers on science, technology and health issues. “The presence of these sizable sources in areas that are potentially attractive targets [for attack] is a major factor making radioactive caesium chloride such a concern to the committee,” according to the report.

The fear is that individuals or groups eager to detonate a dirty bomb in a U.S. city could steal this caesium chloride and combine it with conventional explosives such as dynamite to produce a dirty bomb or radiological dispersal device. The number of caesium chloride irradiating devices appears to be rising in the United States, says the report. According to Leonard Connell at the department of energy’s Sandia National Laboratories in Albuquerque, New Mexico, a member of the panel that produced the report, there is no disposal facility for them. The report proposes that the U.S. government stops licensing new caesium chloride irradiators and discontinues their import and export. It also urges the government to create incentives for owners to decommission devices that rely on radioactive caesium chloride. The U.S. government should also promote alternatives to caesium chloride, urged the council. Possible options include less-hazardous forms of radioactive caesium, radioactive cobalt and other chemicals that cost more but work just as well in medical and research equipment, according to the council’s report.

In a statement, the NRC points out that “eight radionuclides account for more than 99% of the sealed sources that pose the highest security risks in the United States. Caesium-137 in the form of caesium chloride poses greater concern than the others because it is widely used in significant quantities and is soluble and dispersible.” A U.S. Nuclear Regulatory Commission fact sheet on dirty bombs said most types would not release enough radiation to kill people or cause severe illness and that the conventional explosive itself would be more harmful to people than the radioactive material. Such a bomb, though, could spark panic, contaminate property and require a potentially costly cleanup, the agency said.