[Robert McNamara] also said that a nuclear bomb came close to exploding accidentally when a B52 bomber crashed in North Carolina in 1961. He said only a single safety switch prevented the explosion of the 24- megaton bomb.
McNamara provided no other details, saying the message remains classified. But he said, "We damn near had war." He said [Alexei Kosygin] was angry that "we had turned around a carrier in the Mediterranean." McNamara did not explain how the crisis was resolved.
Turning to the nuclear incident in North Carolina, which has been reported earlier, McNamara said a B52 bomber on a training mission was carrying live bombs when it crashed. The accident occurred Jan. 24, 1961 while McNamara was at the Pentagon during the Kennedy administration.