In February 1950 a US Air Force B-36 crashed near the coast of northern British Columbia during a simulated nuclear attack on San Francisco.
A Mark 4 nuclear bomb, which lacked the plutonium core needed for a nuclear blast, was dropped over the ocean before the plane crashed.
12 of 17 men on board survived.
The Convair B-36 “Peacemaker” was a strategic bomber operated by the United States Air Force from 1949 to 1959.
The largest mass-produced, piston-engine aircraft ever built, the B-36 was the first bomber capable of delivering U.S. nuclear weapons over a range of 10,000 mi (16,000 km) without refuelling.
Entering service in 1948, the B-36 was the primary nuclear weapons bomber of Strategic Air Command (SAC) until it was replaced by the jet-powered Boeing B-52 Stratofortress in 1955.
In 2016 a Canadian diver apparently recovered the bomb