It's you that started it Glennm! You just get me searching. I know zero about nitric acid and radioactive things, or rocket boosters for that matter. However all food for thought.
Some things to note, boosters at least , don't seem to break up or make craters in the ground. I've always envisioned an explosion, that might not be the case. In the video it shows them os slight squashed tubes.
With the searching I found people sticking there fingers in nitric acid( diluted) and the skin turning orange!
There may be some merit in a nitric gas cloud. I just don't know enough about it. However, there seems to be a strong connection with rockets and the DP9. Soviet intelligence would be all over the case for sure.