A truck carrying radioactive cobalt 60 used in medical treatments that could be exploited to create a ‘dirty bomb’ has been stolen in Mexico, the IAEA has revealed.
The incident happened on 2 December at night in Tepjaco near Mexico City, while the radioactive material was on its way from a hospital in Tijuana to a radioactive waste storage centre.
Although Mexican authorities have said the material was properly shielded during transportation, it is potentially extremely dangerous if the shielding is removed or damaged.
How much radioactive material was in the truck is not known. The Mexican authorities are currently carrying out an extensive search operation and have issued a press release to alert the public.
Cobalt-60 is the most common radioactive isotope of cobalt, which is frequently used for many industrial applications – for example to detect structural flaws in metal parts. It is also regularly used in radiotherapy. However, exposure to radiation emitted by cobalt 60 could increase the risk of cancer.
"Cobalt-60 has figured in several serious accidents, some of them fatal," said nuclear expert Mark Hibbs of the Carnegie Endowment think-tank. "If dispersed, cobalt-60 or other radioactive source material could cause radiation poisoning locally."
Earlier this year, the IAEA said it receives every year more than 100 reports of incidents of thefts and other unauthorised activities involving nuclear and radioactive material. However, the agency rarely makes such information public, which makes the current case somehow outstanding.
Cobalt 60 could possibly be used to create a so called dirty bomb by mixing it with conventional explosives in order to disperse radiation over a wider area. According to experts, dirty bombs are a more likely weapon to be used by various militant groups than conventional nuclear bombs as they are rather easy to manufacture.
The IAEA considers the use of dirty bombs a high risk, though relative low consequence event, unlike threats involving much more dangerous fissile nuclear bombs, which are not only difficult to manufacture but also require high grade enriched uranium that is far more difficult to access.
At a nuclear security summit in 2012, IAEA Director General Yukiya Amano specifically singled out cobalt-60 among radioactive sources that could be used for dirty bombs.
"These materials, such as cobalt-60, could be used along with conventional explosives to make so-called dirty bombs. A dirty bomb detonated in a major city could cause mass panic, as well as serious economic and environmental consequences," Amano said, according to a copy of his speech.
The veteran Japanese diplomat has repeatedly urged member states to ratify an amendment to the Convention on the Physical Protection of Nuclear Materials to expand its coverage to include domestic use, transport and storage. It now covers only physical protection of materials in international transport.
The IAEA has offered to assist Mexican authorities.