Staying away due to radiation exposure?
Just guessing.
I really don’t have a strong opinion on the validity of this whole thing.
If there were enough radiation extant to keep rescuers more than, say, a mile away then counters would be lighting up all over the world. Anyway, it would be like Chernobyl where some number of crews would be working at zero distance, protected as well as they could be, with other lined up in vehicles at various radiuses mostly upwind. There’s no evidence of any of that. The photo looks exactly like a cloud shadow to me as others have pointed out.
Nor do I...