DOD: On March 11, 1958 at 3:53 p.m. Eastern Standard Time, a B-47E departed Hunter Air Force Base, Georgia as number three aircraft in a flight of four en-route to an overseas base. After level off at 15,000 feet, the aircraft accidentally jettisoned an unarmed nuclear weapon which impacted in a sparsely populated area 6-1/2 miles east of Florence, South Carolina. The bomb's high explosive material exploded on impact. The detonation caused property damage and several injuries on the ground. The aircraft returned to base without further incident. No capsule of nuclear materials was aboard the B-47 or installed in the weapon.
CDI: Accounts of this widely reported accident describe the bomb falling in the garden of the home of Mr. Walter Gregg in Mars Bluff, S.C. The high explosive detonation virtually destroyed his house creating a crater 50-70 feet in diameter and 25-30 feet deep. It caused minor injuries to Mr. Gregg and five members of his family, and additionally damaged five other houses and a church. The clean-up effort required several days. Air Force personnel recovered hundreds of pieces of bomb fragments that were carried off as souvenirs by local residents. The inhabitants of Mars Bluff were examined for several months to see if they had been exposed to any radiation. Five months later the Gregg family was awarded $54,000 from the Air Force. After this accident Air Force crews were ordered to "lock in" nuclear bombs. This reduced the possibility of accidental drops but increased the hazards if the plane crashed.
Triggering a Nuclear Exchange
"The explosion of a nuclear device by accident-mechanical or human-could be a disaster for the United States, for its allies, and for its enemies. If one of these devices accidentally exploded, I would hope that both sides had sufficient means of verification and control to prevent the accident from triggering a nuclear exchange. But we cannot be certain that this would be the case."
John T. McNaughton
Assistant Secretary of Defense