Goose Air Base in Labrador 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 and Mark 4 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. In 1953, Strategic Air Command constructed ten new reinforced concrete buildings as part of a heavily secured weapon storage area located at , surrounded by two barbed wire fences and several armed guard towers. Goose Air Base Weapons Storage Area was the only weapons storage area in Canada constructed to house the Mark 4, AIM-26 Falcon, and AIR-2 Genie nuclear weapons.