Codenamed City 40, Ozersk was the birthplace of the Soviet nuclear weapons program after the Second World War.

Ozyorsk and Richland in the US were the first two cities in the world to produce plutonium for use in Cold War atomic bombs.

[8][9] The Chelyabinsk region has been reported as being one of the most polluted places on Earth, having previously been a center of production of weapons-grade plutonium.

[10] Ozyorsk and the surrounding countryside have been heavily contaminated by industrial pollution from the Mayak plutonium plant since the late 1940s.

[citation needed] In 1957, the Mayak plant was the site of a major disaster, releasing more radioactive contamination than the meltdown at Chernobyl.

An improperly stored underground tank of high-level liquid nuclear waste exploded, contaminating thousands of square kilometres of territory, now known as the Eastern Ural Radioactive Trace (EURT).

In addition to the radioactive risks, the airborne lead and particulate soot levels in Ozyorsk (along with much of the Ural industrial region) are also very high—roughly equal to the levels encountered along busy roadsides in the era predating unleaded gasoline and catalytic converters—due to the presence of numerous lead smelters.

On Sunday September 29, 1957 at 4:22 pm, in the production association "Beacon" in Ozersk one of the containers exploded, in which high-level waste was kept.

The explosion completely destroyed a stainless steel container located in a concrete canyon 8.2 meters deep.

Immediately after the explosion at the facilities of the chemical plant, dosimetrists noted a sharp increase in the background radiation.

In the first hours after the explosion, radioactive substances were brought into the city on the wheels of cars and buses, on the clothes and shoes of industrial workers.

Slavsky wrote: "Investigating the causes of the accident on the spot, the commission believes that the main culprits of this incident are the head of the radiochemical plant and the chief engineer of this plant, who committed a gross violation of the technological regulations for the operation of storage of radioactive solutions".

An Experimental Station was created in the Urals, which played a leading role in studying the consequences of the accident and developing the necessary recommendations.

The average person living in Ozyorsk, 8 km from the Mayak Nuclear Facility, had a long term radioactive burden on their body at 17 Bq.

[15] Reports indicated that humans living in the affected area during the time that the disaster took place and their offspring have developed problems with reproductive functions, mortality, age structure, and sex deformities.