American military leaders were aware of the dangers of radioactive particles long before #Hiroshima or #Trinity.
On #DDay there was a special unit, Operation Peppermint, that came ashore in Normandy with Geiger Counters in anticipation that the Nazis might "pepper" the beaches with uranium particles to sicken and slow the invasion.
Militarization of radioactive particles predated fission weapons.
Yes, and this book was read by Leo Szilard, who was the physicist in the 1930s who in 1935 envisioned the mechanism that would actualize such a weapon, just years before fission was observed in a lab in Germany in 1938.