5. Operation Peppermint assumed the Germans had operating nuclear reactors and radioactive weapons
For the Germans to attack using radioactive devices, they first needed the means of producing them. The devices envisioned by Alsos mission reports required operational nuclear reactors. Alsos assumed the Germans had such reactors at several suspected locations. Operation Peppermint fell under the aegis of the American Assistant Chief of Staff for Operations (G-3), Major General Harold Bull. Bull immediately made the decision, endorsed by Groves, not to inform any of the operational commanders involved in the invasion of Normandy. Operation Peppermint remained highly classified at the senior staff level and officially came under the overall Manhattan Project. It was almost entirely a logistics effort. It required obtaining necessary radiation detection equipment and training operators in their use, held ready for deployment should the need arise. Medical personnel received training in treatments for radiation poisoning.
Operation Peppermint added one more burden to the heavy load borne on Eisenhower’s shoulders as the days ticked down towards the invasion of Europe. Similar reports regarding chemical and gas attacks preceded the invasions of Sicily and Italy in 1943. Those had led to the Allies prepositioning gas weapons of their own, which in turn led to a catastrophic mustard gas incident in the harbor of Bari. An American cargo vessel sank following a German aerial attack, releasing toxic liquid mustard into the harbor. Hundreds of casualties among Allied seamen and troops resulted from exposure to the toxins. A similar nightmare presented itself to Ike as June approached. Operation Peppermint planned to detect radioactivity and possibly limit the exposure to Allied troops, but no effective military countermeasure existed. In the end, one wasn’t necessary. The Germans did not have radioactive weapons.