This is really interesting, thanks for sharing. One thing that surprised me was:
According to one veteran in a Soviet documentary of the event, "Some, the majority even, had no protective clothing, and besides it was impossible to use gas masks" [in the 115-degree Fahrenheit (46-degree Celsius) temperatures of the area].[clarification needed]
"The exercise was conducted on September 14, 1954, at 9.33 a.m"
According to one veteran in a Soviet documentary of the event, "Some, the majority even, had no protective clothing, and besides it was impossible to use gas masks" [in the 115-degree Fahrenheit (46-degree Celsius) temperatures of the area].[clarification needed]
"The exercise was conducted on September 14, 1954, at 9.33 a.m"
46C at 9:33 a.m., mid-September in 1954?
https://weatherspark.com/h/d/148893/1954/9/14/Historical-Wea...
I think the Soviet documentary quote might be talking about some entirely other event?