The Palomares hydrogen bomb incident is a military accident that occurred on January 17, 1966. A United States bomber aircraft collided with a tanker aircraft during refueling about 6 miles (10 km) over the Mediterranean sea, just off the coast of Spain. This ignited the fuel compartment of the tanker, causing it to explode, killing all four crew members on board. The bomber broke up as well, killing three crew members. Four crew members survived and parachuted to safety. The explosion was so large it was witnessed by the crew of another bomber over a mile away.
The incident became known as the Palomares hydrogen bomb incident because the bomber was carrying four hydrogen bombs, all of which fell near the fishing village of Palomares. Conventional explosives in two of the bombs detonated, contaminating two square kilometers of Spanish soil with radioactive plutonium. Another bomb hit the ground without incident, and the last bomb fell into the Mediterranean sea, prompting a 2 1/2 month long search. Obviously, the United States military did not want the hydrogen bomb to fall into the wrong hands.
The Palomares hydrogen bomb incident obviously became an international fuss soon after it happened, and the United States government worked to clean up the area of contaminated soil, excavating 1,750 tons of soil and disposing it at the Savannah River Plant in South Carolina. To show local Spaniards and the international community that the area was free from contamination, Spanish tourism minister Manuel Fraga and US ambassador Angier Biddle Duke swam on the beach off Palomares, in full view of the international media.
But putting an end to the Palomares hydrogen bomb incident required finding the last hydrogen bomb, which was not so easy. Using initial data supplied by Francisco Simó Orts, a local fisherman who saw the bomb enter the water, a mathematical technique called Bayesian search was used to search the sea floor for the bomb. The famous deep-sea oceanographic vessel Alvin was used to search the area. After 2 1/2 months of continuous searching, the bomb was retrieved and brought back to the surface. A photograph of military officials in front of the recovered bomb was subsequently released, the first time that a nuclear weapon was seen in full view of the public.
The Palomares hydrogen bomb incident now goes down in history as one of the foremost anomalous incidents involving nuclear weapons. Another is the Vela incident, when a nuclear explosion of unknown source origin near the South Atlantic Bouvet Island.
