January 17, 1966, an SAC B-52 had a mid-air collision with a KC-135
tanker while refueling over Palomares, Spain. The B-52 was carrying
four thermonuclear B28 bombs. The bomber had begun the mission at
Seymour Johnson AFB, North Carolina. The KC-135 had come from the
Moron Air Base, Spain. All four KC-135 crew members were killed, while
four of the seven B-52 crew parachuted to safety.
President Lyndon Johnson, the Department of Defense, the Atomic
Energy Commission, and the Spanish Government received news of the
nuclear accident. Nuclear safety teams were dispatched immediately.
Within hours, the 16th Air Force had located the three B28 bombs
that landed on the shore. However, the fourth bomb was missing;
it was not found for 80 days. High explosives in two bombs had detonated
on impact. Plutonium dust had spread over several hundred acres.
One reassuring fact emerged from this incident: inherent safety
features designed and built by Atomic Energy Commission contractors
ensured that no nuclear explosion occurred.