A possible Chernobyl-scale nuclear disaster threatens the fertile Fergana valley in Central Asia as Soviet-built dams holding vast amounts of uranium mine tailings that sit above the region are unstable, studies are said to have revealed.

If the dams collapse, the spillage of the tailings would make the vicinity uninhabitable.

The dams, located in Kyrgyzstan, hold some 700,000 cubic metres (185mn gallons) of uranium mine tailings. Assessments have shown that they became unreliable following a 2017 landslide. A further landslide, or an earthquake, could pollute the river system used to irrigate Kyrgyz, Uzbek and Tajik farmlands in the Fergana valley and lead to the displacement of millions of people.

The studies of the radioactive waste disposal facilities were conducted as part of a European Commission and European Bank for Reconstruction and Development (EBRD) project to reinforce the facilities. According to a Reuters report published on April 23, they showed that the waste type involved cannot be safely contained in the currently used locations and needs to be transferred away from the banks of the Mailuu-Suu river.

"If a landslide causes the river to burst, the waste from two mine dumps will enter the water," Gulshair Abdullayeva, a manager of the Mailuu-Suu radiology lab, was cited as saying, adding: "The environmental disaster would almost be comparable with Chernobyl."

Some 16mn people live in the Fergana valley, the most densely populated area in Central Asia. Cotton, rice, grains, fruit and vegetables are among crops grown there.

Studies have highlighted how the waste in the dumps—located near the town of Mailuu-Suu, they in fact make up one of the world’s biggest uranium ore dumps—is liquid, making it more hazardous, Sebastian Hess, an engineer with German firm G.E.O.S., contracted by the Kyrgyz government, told Reuters, pointing out that the consequences of a strong earthquake might mean it flowing into the river.

"That would be a horrible catastrophe," he was reported as saying. "This water is used to irrigate fields which means agricultural produce would be contaminated."

The 2017 landslide weakened the dams' foundations and raised the river's water level, bringing it closer to the tailings, according to engineers.

An estimate prepared by Kyrgyzstan’s government and G.E.O.S. concluded that around €22-25mn would be required to transfer the waste at the two sites to a location further away from the river.