Two U.S. Air Force planes were flying off the southern coast of Spain on January 17, 1966. One, a B-52 Stratofortress carrying four B28 nuclear bombs, needed refueling. Seven crew members were aboard.
A KC-135 Stratotanker carrying 40,000 gallons of fuel was about to provide the B-52 with enough fuel to return to its base in North Carolina. Four crew members were aboard.
About 8 kilometers off the coast, not far from the village of Palomares, the two planes collided in mid-air. With its full load of fuel, the KC-135 exploded. All four crewmen were killed.
The B-52 also exploded. Three crewmen were killed and all four hydrogen bombs on board the plane plummeted to earth. One, guided by an activated parachute and nicknamed "Robert,” fell into the Mediterranean. (Follow the link to a Navy photo of the bomb resting in 2,800 feet of water.)
An eyewitness, Francisco Simo y Orts saw the bomb fall into the sea, about 75 yards from his boat. He thought he had seen “a dead man” and drew pictures of what he observed.
The other three bombs landed on Spanish soil. The parachute of one land-bound B28 bomb activated, and the bomb did not explode. The other two parachutes failed, causing the bombs to undergo non-nuclear, high explosive detonation.
One detonated bomb - “weapon #2" - landed 1.7 kilometers west of the village of Palomares. It dispersed plutonium dust-bearing clouds over uncultivated fields (“impact zone #2") on the northern edge of Palomares. The other - “weapon #3" - landed just east of Palomares. Plutonium dust-clouds from it dispersed over cultivated fields.
A total of 558 acres were contaminated with radioactivity. Fortunately, none of the 1,500 people in the village sustained injuries. Within weeks, the United States removed about 1,400 tons of contaminated soil (“Project Indalo") from Palomares and transported it for burial at the Savannah River Site in South Carolina.
But months after the mid-air collision, bomb #4 was still missing. It was somewhere off the coast of southern Spain. The U.S. Navy had to locate it and get it out of Spanish waters.
That’s where Carl Brashear and the USS Hoist entered the scene.