In 1979, Soviet authorities conducted a peaceful nuclear explosion underground at the "Klivazh" site within the Yunkom mine.

According to a report by the minister of environmental safety Vasyl Shevchuk, flooding the mine could lead to radioactive contamination of nearby groundwater.

[5][6] OSCE observers provided information signaling that the DPR militants in control of the mine planned to flood the areas of the nuclear explosion.

The US Department of State spokesperson, Heather Nauert, expressed concern in response to this observation in a post on Twitter.

[8] In response, Ukrainian MP Oleh Nedava urged residents in Donbas not to drink tap water, and stressed the irreversibility of radioactive contamination in the local river system.