From the intro:
"...yet it was thanks to these men that the worse was avoided -- a second explosion, ten times more powerful than Hiroshima, which would have wiped out half of Europe. This was kept secret [for the next 20 years] by the Soviets and the West alike. Many of these images have never been seen before..."
I didn't know that. Did you? I will see if I can dig up some broadcasts from the time -- let's see, April through November 1986. What were they telling us? No harm to human health, no doubt.
Be seeing you.