>>64123037
Less so than the Axis comparitively knew about atomic weapons. The Allies basically ignored its potential for weaponization in favor of "good enough" phosgene and mustard and were completely lapped by Germany in this regard. Not that it ended up mattering.

Fully protective PPE absolutely was a post war development. The closest thing to MOPP style gear was essentially just a impractically cumbersome rubber suit that was far too heavy and expensive to see field use or anything approaching mass manufacture. Chemical protection at the time consisted of a mask and maybe a plastic bag that didn't cover you entirely, and both were meant for WW1 era gas attacks.