Declassified NRC Document Sheds Light on Kyshtym Nuclear Explosion

The release of a Freedom of Information Act (FOIA) document by the U.S. Nuclear Regulatory Commission (NRC) sheds light on a long-suspected nuclear accident in the Soviet Union during the late 1950s. This document, titled “Information on Nuclear Accident in U.S.S.R. in Late 1950’s” (SECY-78-305), responds to inquiries about a reported catastrophic event that has been shrouded in secrecy and speculation for decades.

The document reveals that on September 29, 1957, a significant nuclear accident occurred in the Chelyabinsk region, part of the Ural Mountains. This event, often referred to as the “Kyshtym disaster”, involved an explosion at a nuclear waste storage facility near the town of Kyshtym. The facility was part of the Mayak Production Association, a major Soviet nuclear complex involved in producing plutonium for weapons.

According to various intelligence reports cited in the document, the explosion resulted from the overheating of buried nuclear waste. The containment measures failed, leading to a release of highly radioactive materials into the environment. This incident caused widespread contamination, affecting a large area and exposing thousands of people to dangerous levels of radiation.

The NRC document includes excerpts from several declassified CIA reports. One such report from May 1958 details that “various Soviet employees and visitors to the Brussels Fair have stated, independently but consistently, that the occurrence of an accidental atomic explosion during the spring of 1958 was widely known throughout the USSR”​​. The explosion site was identified as being in the Chelyabinskaya Oblast, and while the exact number of casualties remains uncertain, it was commonly believed that several scores of individuals perished in the incident​​.

Further intelligence describes the aftermath of the explosion, with extensive radioactive contamination rendering a significant area uninhabitable. Eyewitness accounts from the time recount that “all stores in Tomensk-Uralskiy which sold milk, meat, and other foodstuffs were closed as a precaution against radiation exposure”​. New food supplies were brought in under strict controls, and the population was subjected to measures reminiscent of wartime shortages.

The NRC document also references the account of Zhores Medvedev, a Soviet biochemist and geneticist who defected to the West. Medvedev reported that the Soviet authorities had kept the disaster under wraps, not evacuating affected populations until symptoms of radiation sickness became apparent. This delay in response exacerbated the health impacts, leading to numerous deaths and chronic illnesses among the exposed population​.

Additionally, the NRC document includes details from a Soviet film, classified at the time, which showed the construction of a new city in the Ural Mountains specifically for testing a 20-megaton nuclear device. The test’s objectives included assessing the resilience of civilian infrastructure, such as a subway system, to a nuclear blast. The film depicted the obliteration of the city, with only the subway surviving, highlighting the devastating power of the explosion and its impact on both military equipment and animal life used as test subjects​​.

Despite the magnitude of the disaster, Soviet officials consistently denied any knowledge of such incidents during interactions with U.S. delegations. For instance, during meetings in the USSR, Soviet officials, including L. M. Voronin, claimed ignorance about the accident and insisted that their agencies were only involved in peaceful nuclear activities​.

The secrecy and disinformation surrounding the Kyshtym disaster are indicative of the broader context of Cold War-era nuclear accidents, where both superpowers often concealed the true extent of their nuclear mishaps to maintain strategic and political advantages. The release of these documents provides a rare glimpse into the hidden history of nuclear risks and the human cost of the nuclear arms race.

###

Document Archive

FOIA Case NRC-2021-000112 Release Package [33 Pages, 4MB]

Follow The Black Vault on Social Media: