Atmospheric sampling is nuffink new and was part of the mil/scientific support which existed in those days, because we were all on the same side!
Go forth and read the history of the Canberra and Victor
PR/SR fleets - how else do the boffins learn about yield, distribution etc? In the late 50's don't forget, the state of knowledge was based upon analysis post Nagasaki etc. It wasn't until the 80's that further analysis suggested the error of calculation that had occurred back then, and led to instant re-assessment of ionising radiation safety levels. But it is IMHO wrong to try and blame the rules back then - the ignornace was mutual.