DRC probes how uranium ‘leaked’ into cobalt exports

The Democratic Republic of Congo is investigating uranium contamination in cobalt exports after researchers estimated that thousands of tonnes of the radioactive metal probably left the world’s largest cobalt-producing nation over the past two decades.

The government said it would test cobalt hydroxide exported largely to China and establish a working group to assess findings published July 30 in Nature Communications and examined in a Financial Times and Lighthouse Reports collaborative investigation.

Kinshasa also plans to consult the International Atomic Energy Agency (IAEA) about arranging a technical support mission, while domestic authorities will assess potential health and environmental risks over the next 60 days and make their findings public.

The investigation comes as demand for cobalt, a key material in some lithium-ion batteries, has made the DRC’s Copperbelt central to global supply chains. Uranium occurs naturally alongside copper and cobalt ores across the region and can remain attached to cobalt minerals as they move through mining and processing.

Blind spot

Researchers from the University of Wisconsin-Madison and Princeton University estimated that between 2,000 and 5,000 tonnes of natural uranium were exported from DRC in cobalt-hydroxide shipments between 2000 and 2024, despite the country reporting no official uranium production during that period.

The study combined country-wide mineralization and geochemical data, mine-level trade records and a chemical model of cobalt processing. It also estimated another 1,000 to 4,000 tonnes of uranium may have been discarded in mine tailings, potentially exposing workers and nearby communities to chemically mobile radioactive material.

Less than 10% of the exported material appears to have been publicly declared and placed under international safeguards, according to study co-author Sébastien Philippe, a nuclear security expert and assistant professor at the University of Wisconsin-Madison.

“This quantity of undeclared uranium could be used to produce fissile material for roughly 600 to 1,500 nuclear weapons or fuel a standard light-water nuclear reactor for 10 to 25 years, so it’s quite a large amount,” Philippe said.

He stressed that the research did not show uranium was deliberately exported through the cobalt supply chain.

“Our scientific research doesn’t show this was done purposefully to get uranium out of the DRC,” Philippe said. “However, one of the things we’re concerned about is that the volumes of exported uranium we’ve quantified are beyond what is supposed to be declared to the IAEA.”

China-bound

Most cobalt shipments went to China, which the researchers said is home to about 95% of global cobalt refining capacity. Uranium contained in crude cobalt hydroxide must be removed during refining, potentially leaving it as a recoverable byproduct.

While the IAEA tracks uranium production worldwide, the DRC’s low-grade uranium-bearing cobalt exports do not require reporting when shipped for non-nuclear purposes. An IAEA expert cited in the reporting said the agency had no indication that the DRC was failing to meet its safeguards obligations.

The Congolese government also challenged parts of the study, saying its estimates were not based on direct measurements of exported material and relied instead on modelling that was not specific to individual facilities.

“These methodological limitations call for a counter-verification process, without in any way minimizing the issues raised,” the government said.

Officials said national and international laboratories would participate in the testing, alongside the DRC’s nuclear safety and nuclear energy agencies. The country also plans to install radiation detectors for trucks leaving the country.

Miners push back

Chinese mining companies operating in the DRC have rejected claims that their cobalt products contain excessive uranium.

The Union of Chinese-Capital Mining Companies in the DRC, known known by its French acronym USMCC, said Aug. 5 that an internal review found no excessive uranium levels in cobalt products mined, processed or exported by its members in southeastern DRC.

“Following an exhaustive verification conducted by the association, no cobalt product extracted, processed or exported by Chinese mining companies operating in southeastern DRC contains excessive levels of uranium,” USMCC said in a statement published on X.

The group acknowledged that cobalt hydroxide can contain very low naturally occurring traces of uranium, but said concentrations remained below levels that would make extraction technically or economically viable.

“There are no economic or technical conditions for recovering, extracting or exploiting this uranium,” it said.

Major Chinese mining companies operating in the DRC include CMOC Group, Zijin Mining and Zhejiang Huayou Cobalt.

USMCC said its members would conduct regular sampling, publish quality-control findings and continue complying with Congolese mining rules and internationally recognized testing standards.

Added pressure

The dispute adds another complication to a cobalt industry already facing pressure over supply-chain transparency, worker safety and local processing. The DRC has also prohibited exports of copper and cobalt concentrates as part of efforts to retain more value from its mineral resources.

Researchers said more systematic testing of cobalt-hydroxide shipments, radiation monitoring for workers and better accounting of uranium flows could reduce the risks. Ultimately, they argued that refining cobalt into metal inside the DRC would give authorities greater control over uranium before cobalt leaves the country.

Kinshasa says that uranium has coexisted with cobalt in Congolese ores throughout more than a century of industrial mining, and that the issue has been responsibly managed.

The DRC “remains committed to fulfilling its international non-proliferation and safeguards obligations,” it added.