Nikolai Thibeaux-Brignolle and Georgy Yuri Krivonishchenko were employed at the secret Mayak atomic plant, some 120 kilometers south of Sverdlovsk.
Mayak atomic combine is associated with the very first in human history radioactive contamination accidents, called the Kyshtym disaster.
On September 29, 1957, the cooling systems of the tank, which stored tens of thousands of tons of dissolved nuclear waste, malfunctioned. The malfunction resulted in a powerful explosion and contamination of groundwater and land within a radius of hundreds of kilometers. As a result, and combined with the very negligent, nonchalant, and irresponsible approach of the Soviets to safety issues, the Tiecha River was contaminated, and consequently the Ob River, which flows into the Gulf of Ob on the Kara Sea. Hundreds of thousands of people living in the river basin were exposed to ionizing radiation far above standards. According to official figures, more than 200 people have died as a result of acute radiation sickness. Most likely, the number of fatalities is many times underestimated.
Information about the Kyshtym catastrophe came to light only in 1992, when Lev Ivanov, the prosecutor investigating the Dyatlov Pass incident, leaked the information to the public.