10 Drums of Nuclear Material Are Missing From Libya Site, U.N. Agency Says

More than 2.5 tons of natural uranium is missing from a site in war-torn Libya, the director general of the U.N. nuclear watchdog said on Wednesday, telling member states that the agency was searching for the material.

The uranium ore itself poses little radiation hazard, said Sinead Harvey, a spokeswoman for the U.N. watchdog, the International Atomic Energy Agency. But she said the material, contained in 10 drums, still requires safe handling and may present “a radiological risk as well as nuclear security concerns” if it were not found.

The nuclear material was discovered to be missing on Tuesday during an inspection in Libya by the U.N. watchdog, Ms. Harvey said.

The agency’s director general, Rafael Grossi, informed U.N. member states about the missing barrels the next day, the I.A.E.A. said in a statement. The agency did not say where the inspection took place, or whether the site was under the control of Libya’s government.

Independent experts on arms control agreed with the I.A.E.A assessment that the material was not necessarily an immediate danger.

“It’s uranium concentrate, often called yellowcake, which means its mostly Uranium-238 and not itself a big worry in terms of nuclear proliferation,” said Patricia Lewis, a nuclear physicist and arms control expert. “Radiation that comes out of this type of uranium is very low.”

”But what can happen, and this has been a concern for a long time, is that nonstate armed groups could pack a conventional bomb with this stuff,” said Ms. Lewis, who leads the International Security program of Chatham House, a London-based research group.

Zia Mian, a physicist and expert on nuclear proliferation at Princeton University, said that the quantity of missing material falls under a 10-ton threshold set by the I.A.E.A. The agency considers that the approximate amount of nuclear material for which the possibility of manufacturing a nuclear explosive device cannot be excluded, he said.

The I.A.E.A. described the inspection site as “declared by the State of Libya under the Additional Protocol,” referring to a 2004 agreement which granted the U.N. nuclear watchdog’s inspectors greater access to sites in the country to assess the country’s now-defunct nuclear program.

Libya’s leader in 2003, Col. Muammar Gaddafi, renounced his nuclear weapons program after the U.S. invasion of Iraq, and having already procured centrifuges that enabled the country to enrich uranium. Much of the equipment related to Libya’s nascent nuclear and ballistic missile programs was flown out of the country to a facility in Tennessee.

The last of Libya’s enriched uranium was removed from the country in 2009, according to the United Nations. But the body estimated in 2013 that some 6,400 barrels of yellowcake remained in southwestern Libya, and its inspectors have continued efforts to inspect Libyan sites.

They have faced dangerous hurdles to their work over the last decade, since Colonel Gaddafi lost control over the country in a popular revolt. The United States and its European allies launched airstrikes in support of the uprising against him in 2011, and he was killed and his government toppled that year.

In the years since, Libya has been divided by warring factions and political crises — creating many obstacles for the U.N. nuclear watchdog.

The inspection this week had originally been planned for last year, but “had to be postponed because of the security situation in the region,” according to a report by Reuters, which cited a confidential statement by the I.A.E.A. director general, Mr. Grossi. The agency did not immediately respond to a questions about that report.

Ms. Lewis, the Chatham House expert, said that U.N. inspectors “haven’t been able to keep an eye on,” nuclear material in Libya. She added that the potential threat of the material “completely depends on where it’s gone.”

“It’s either gone missing by accident, which sounds ridiculous but has happened in the past,” she said, noting the recent example of a radioactive capsule lost in the desert of Western Australia. ”Or it has been sold to a country outside the normal reporting and safeguarding mechanisms,” she added.

Another possibility was that smugglers took the material without fully understanding its value, she said, adding that this had happened at the end of the Cold War and could result with uranium on the international black market.

“There’s just too many unknowns right now,” she added.

The I.A.E.A. did not respond to a request for clarification on Thursday about whether the Libyan authorities had requested their assistance in locating the missing nuclear material. Ms. Harvey said the agency “stands ready,” at Libya’s request, “to provide the necessary assistance on this issue for the application of international nuclear safety standards and nuclear security guidance.”