The person responsible for providing this information was prosecutor Lev Ivanov, who was investigating the mysterious case of the Dyatlov Pass incident. Two of the participants in the tragic mountain expedition had worked at the Mayak combine, and one of them - Georgy Yuri Krivonishchenko - had participated in the cleanup of the 1957 explosion.
Ivanov was initially "encouraged" to close the investigation, and after the collapse of the USSR, he revealed information about the Mayak incident in a press interview.
CIA reports from the 1950s and 1960s indicate that U.S. services were well aware of the disaster and did not disclose this information. The reason may have been the need to observe the Soviet reaction to the disaster, which the Americans had not experienced on their territory. In addition, information about the nuclear catastrophe could have led to protests and sabotage of the nuclear enterprise within the United States.
