Mexican thieves steal cobalt-60
Thieves have stolen a truck in Mexico carrying a dangerous radioactive source used in medical treatments, a material that could also provide an ingredient for a so-called "dirty bomb".
The UN nuclear agency said it had been informed by Mexican authorities that the truck, which was taking cobalt-60 from a hospital in the northern city of Tijuana to a radioactive waste-storage centre, was stolen near Mexico City on Monday.
Apart from peaceful medical and industrial uses, experts say cobalt-60 can also be used in a dirty bomb in which conventional explosives disperse radiation from a radioactive source.
The International Atomic Energy Agency, which has stepped up calls on member states to tighten security to stop nuclear and radioactive materials falling into the wrong hands, made no mention of any such risk in its statement yesterday.
The IAEA also did not give details on how much radioactive material was in the vehicle .
"At the time the truck was stolen, the [radioactive] source was properly shielded. However, the source could be extremely dangerous to a person if removed from the shielding, or if it was damaged," the IAEA said.
The IAEA has offered to assist Mexican authorities, who it said were searching for the material and had alerted the public.
Cobalt-60 - the most common radioactive isotope of cobalt, a metal - has many applications in industry and in radiotherapy in hospitals. It is also used for industrial radiography to detect structural flaws in metal parts, according to the US Environmental Protection Agency.
The EPA said exposure to gamma radiation from cobalt-60 results in increased cancer risks.
"Cobalt-60 has figured in several serious accidents, some fatal," nuclear expert Mark Hibbs of the Carnegie Endowment think-tank said. "If dispersed, cobalt-60 or other radioactive source material could cause radiation poisoning locally."
More than 100 incidents of thefts and other unauthorised activities involving nuclear and radioactive material are reported to the IAEA annually, the UN agency said earlier this year.
It is rare, however, that it makes any such incident public.
Because radioactive material is less hard to find and the device easier to manufacture, experts say a so-called "dirty bomb" is a more likely threat than a nuclear bomb in any attack by militants.
Experts describe the threat of a crude fissile nuclear bomb, which is technically difficult to manufacture and requires hard-to-obtain bomb-grade uranium or plutonium, as a "low probability, high consequence act" - unlikely but with the potential to cause large-scale harm.