Question: What did the United States Army use during Operation Peppermint to prevent the Germans from  disrupting the 1944 Normandy Landings?
Sentence (from "Operation Peppermint"): Operation Peppermint was the codename given during World War II to preparations by the Manhattan Project and the European Theater of Operations United States Army (ETOUSA) to counter the danger that the Germans might disrupt the June 1944 Normandy landings with radioactive poisons.
Relevant evidence: Yes