Goose Air Base was the site of the first US nuclear weapons in Canada, when in 1950 the United States Air Force Strategic Air Command stationed 11 model 1561 Fat Man atomic bombs at the base in the summer, and flew them out in December. While returning to Davis–Monthan Air Force Base with one of the bombs on board, a USAF B-50 heavy bomber encountered engine trouble, had to drop, and conventionally detonate, the bomb over the St. Lawrence, contaminating the river with uranium-238.