Radioactive waste dumped in Karatchaï lake

In 1951, Soviet authorities diverted highly radioactive waste from the Maïak nuclear plant to a small lake in the Ural Mountains called Karatchaï, also known as "Reservoir 9." This decision aimed to protect nearby villages that had already been contaminated by the Techa River, which had been polluted by earlier discharges from the plant.

Lake became one of the most contaminated places

The lake became one of the most contaminated places on Earth. By 1990, radiation levels near the discharge point reached about 600 röntgens per hour, a dose that could be lethal within an hour of exposure. A 1993 study found that the lake emitted the equivalent of 120 million curies of radioactivity, or 4,440,000,000,000 megabecquerels.

Lake’s surface shrank over time

The lake’s surface area shrank from 0.5 km² in 1951 to just 0.15 km² by 1993 as it began to dry up in the 1960s. This drying exposed radioactive sediments to the air, allowing wind to resuspend radionuclides and further contaminate the Techa River.

Efforts to stabilize the lake

Between 1978 and 1986, Soviet engineers submerged nearly 10,000 hollow concrete blocks in the lake to stabilize the sediments. These efforts continued until the 2000s, when a Russian federal program called "Nuclear and Radiological Safety" aimed to completely fill the lake instead of managing its overflow. The lake was finally filled and turned into a dry storage facility in November 2015, with a final layer of rock and soil covering the concrete blocks.

Contamination continued despite efforts

A Russian court found that between 2001 and 2004, approximately 30 to 40 million cubic meters of radioactive waste still reached the Techa River, contaminating it with strontium-90. The Maïak complex, now operated by Rosatom, still carries the legacy of one of the darkest chapters in global nuclear energy history. The site remains closely monitored, but its radioactive impact continues to affect the region.