The 1966 Palomares B-52 crash or Palomares incident occurred on 17 January 1966, when a B-52G bomber of the United States Air Force’s Strategic Air Command collided with a KC-135 tanker during mid-air refuelling at 31,000 feet (9,450 m) over the Mediterranean Sea, off the coast of Spain. The KC-135 was completely destroyed when its fuel load ignited, killing all four crew members. The B-52G broke apart, killing three of the seven crew members aboard.
Of the four Mk28-type hydrogen bombs the B-52G carried, three were found on land near the small fishing village of Palomares in the municipality of Cuevas del Almanzora, Almería, Spain. The non-nuclear explosives in two of the weapons detonated upon impact with the ground, resulting in the contamination of a 2-square-kilometer (490-acre) (0.78 square mile) area by plutonium. The fourth, which fell into the Mediterranean Sea, was recovered intact after a 2½-month-long search.