Question about the end (spoiler) and the cause of shrinkage
Just before he shrinks into nothing, Scott wonders that if there were other radioactive clouds like the one he encountered on the boat, then maybe other people would shrink to the same infinitely small size as himself.
But is he forgetting that it was the interaction of the radioactive mist and the insecticide he had been sprayed with that caused him to shrink ?
Or was he thinking that the environment had become so polluted that sooner or later someone would be exposed both to insecticide and to radioactive clouds (from atomic testing, presumably), and thus undergo the same chemical reactions that caused him to shrink ?