Published online 11 September 2009 | Nature | doi:10.1038/news.2009.906

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Radioactive cobalt cleared from Lebanese lab.

Recovering 'lost' radioactive sources can reduce the risk that they will fall into terrorists' hands. Getty

The International Atomic Energy Agency (IAEA) has repatriated dozens of Russian-made, highly radioactive sources that had been languishing unused in a Lebanese research institute for more than a decade.

The effort forms part of a wider IAEA initiative to secure radioactive materials used in scientific research, medicine and industry, which could potentially be used by terrorists to make a so-called 'dirty bomb'.

IAEA officials identified possible security issues with the radioactive material at an unspecified agricultural institute in Lebanon in 2006. They were concerned to find that a cobalt-60 irradiator, originally used for a biological pest control project, had been lying dormant since 1996. The sealed unit still contained 36 individual sources with a combined activity of 3,500 Curies, making it the most powerful source of radioactivity in Lebanon.

The irradiator had previously been used to sterilize male Mediterranean fruit flies or medfly (Ceratitis capitata), with a view to controlling the medfly population and preventing crop damage by egg-laying females. But after the project ended, all the staff members who knew how to look after the radioactive equipment subsequently left the institute, leaving the cobalt-60 sources potentially insecure.

“It's a thousand-piece jigsaw puzzle and this is at best one piece.” Matthew Bunn

Harvard University

The sources were fully shielded, so there was no risk to research staff entering the room where the irradiator was stored. "We were worried about the risk of theft, either for the value of the irradiator or particularly for malicious purposes," said Robin Heard, an IAEA radioactive source specialist who oversaw the mission. If the sources had been removed from the container, direct exposure to the radioactive material could have killed someone within minutes.

Source of worry

Plans to repatriate the radioactive material were initially delayed, owing to general political instability in the region, and in particular Israel's bombing of Lebanon's airport, which prevented outgoing flights. The sources were finally moved to a secure storage facility in Russia on 30 August.

"This is a big enough set of sources to be worrisome were it to fall into terrorists' hands," says Matthew Bunn, a non-proliferation expert at Harvard University. "Lebanon is certainly a country with some fairly substantial terrorist activity."

The IAEA's repatriation mission in Lebanon was a piece of "good international housekeeping", adds John Simpson, an expert on nuclear non-proliferation at the University of Southampton's Mountbatten Centre for International Studies, the United Kingdom. "It is clearly extremely sensible that the IAEA should try to get all states to account for all radioactive sources that are within their territories."

While this operation was a success, it merely scratches the surface of a global problem, says Bunn: "It's a thousand-piece jigsaw puzzle and this is at best one piece."

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The IAEA has identified more radioactive material that it would like to remove from Lebanon, although the location and activities of these sources is not being made public. The cost of the removal programme has been met by the European Union.

IAEA officials are also working in Africa and former Soviet Union satellite states to improve the security of radioactive materials. In the Ukraine, for example, a centralized storage facility is planned to house used radioactive sources from across the country. Construction of the facility within the Chernobyl exclusion zone is expected to begin later this year. The UK government has pledged £2.1 million from its Global Threat Reduction Programme towards the scheme.