There were hundreds of open air nuclear weapons tests during those years. None of them were conducted around American cities although there were likely some fallout effects downwind. By contrast, those biological and chemical tests were sometimes conducted in US cities using unknowing civilians as test subjects. IMO, they were as immoral as the infamous Tuskegee Syphillis Experiment (where black men with syphillis weren't treated for 40 years so they could be monitored as the course took its cruel course) or those experiments where innocent civilians were exposed to radioactive materials to see what the effects would be.

Lest anyone try to make political hay out of these "tests", many of them spanned both Democrat and Republican administrations. I don't know if any of the presidents in office during those years knew what was going on at the time.