The S.Carolina accident was a few years earlier. From Wikipedia:
# March 11, 1958 Mars Bluff, South Carolina, USA Non-nuclear detonation of a nuclear bomb
* A USAF B-47 bomber flying from Hunter Air Force Base in Savannah, Georgia accidentally released an atomic bomb. A home was destroyed and several people injured but the bomb’s plutonium core did not explode.
Wouldn't that nearly ruin your day, having a nuclear bomb fall on your house.