A Hidden Cost of the Clean Energy Transition
Emissions from a Chinese cobalt-processing plant in central Africa sickened residents and workers as the company raced to increase production of a mineral critical to making electric-car batteries, an environmental group says. The findings, released in a 140-page report by London-based research organisation Earthwatch Congo Initiative, document sulphur dioxide plumes, heavy-metal contaminated groundwater, and a sharp rise in respiratory illness in the Lualaba Province of the Democratic Republic of Congo.
The Plant and the Operator
The facility, operated by a subsidiary of Zhejiang Huayou Cobalt — one of the world's largest cobalt refiners — was built in 2019 and dramatically expanded between 2023 and 2025 as global demand for cobalt, a key component in lithium-ion batteries used in electric vehicles, surged. Output at the plant roughly tripled over two years as automakers including Tesla, BYD, Volkswagen, and Stellantis competed for long-term supply agreements.
Earthwatch Congo's field researchers recorded sulphur dioxide concentrations 4.7 times the World Health Organisation's safe ambient air standard at monitoring stations within 2 km of the plant perimeter. Cobalt dust was found in drinking water wells at concentrations 12 times WHO limits in villages within a 5 km radius.
Health Impacts on Local Communities
Medical records obtained by the organisation from three local clinics show a 340% increase in acute respiratory illness presentations since 2023. Children under 12 account for 47% of cases. Symptoms described include persistent coughing, skin lesions consistent with heavy-metal exposure, and developmental delays in infants born to mothers who worked at or near the facility during pregnancy.
"We have been telling the company and the government for two years that people are sick," said Celestin Mwamba, a community leader from the village of Kasulo. "Nothing changes. The trucks come, the ore leaves, and our children keep coughing."
Company and Government Responses
Zhejiang Huayou Cobalt said in a statement that it "strictly adheres to all applicable environmental regulations in the DRC and invests significantly in emission control technology." The company said it would commission an independent environmental audit. The DRC's Ministry of Mines did not respond to requests for comment.
Supply Chain Implications
The report is likely to intensify scrutiny of cobalt supply chains at a time when the EU's Battery Regulation and the US Inflation Reduction Act both impose due-diligence requirements on automakers and battery manufacturers. Several European carmakers have pledged to eliminate conflict minerals from their supply chains by 2028, but enforcement mechanisms remain weak.
Cobalt prices on the London Metal Exchange were little changed on the day of the report's release, suggesting markets have not yet priced in potential supply-chain disruptions. However, analysts at Wood Mackenzie warned that regulatory action against the facility could tighten an already fragile cobalt market in which the DRC supplies roughly 70% of global output.
The Broader EV Paradox
The episode underscores a deepening paradox in the global push for electric vehicles: the clean-energy transition depends heavily on mining and processing practices in developing nations where environmental enforcement is often weak. While EV manufacturers promote zero-emission credentials, the upstream supply chain increasingly comes under fire for its environmental and human cost.
