If you are in the mood for going down rabbit holes, try this on for size:

https://gizadeathstar.com/2019/03/more-antarctic-strangeness-from-1958/

there appeared to have been a nuclear explosion either above the ground, or below it. As the articles indicate, at first the story was denied, then more or less affirmed, and President Kennedy ordered the Antarctic treaty's provisions to allow nations with bases there to inspect each other; the inference being that the Soviets had tested some sort of nuclear bomb. According to the video narrative accompanying the shots of the newspaper articles, the explosion occurred sometime in August, 1963, only months before President Kennedy's assassination.

Nukes would be a great way of sterilizing a biolab or biological test area that had stuff get out of control. And again, something that cant exactly happen in any populated area.