On January 17, 1966, a United States Air Force B-52G bomber collided with a KC-135 refueling tanker at 31,000 feet directly over the quiet coastal village of Palomares, Spain. The disaster resulted in the loss of seven crew members and the release of four B28 thermonuclear bombs. While none of the weapons detonated nuclear yields, the non-nuclear conventional explosives in two of the bombs exploded upon impacting the ground, detonating like dirty bombs and shattering their plutonium cores.
This scattered highly toxic, radioactive plutonium-239 and americium dust over approximately 550 acres of Spanish agricultural fields, tomato patches, and residential areas. The United States military launched a massive cleanup operation named Operation Indio, removing over 1,400 tons of contaminated soil and vegetation, which was packed into 55-gallon drums and shipped to Aiken, South Carolina, for long-term disposal. Despite these efforts, residual radiation persisted in the local ecosystem for decades.
The incident sparked severe international outrage, leading the U. S. to permanently ban overland flights carrying nuclear arms over European soil.
Decades later, soil tests revealed remaining hot spots, forcing ongoing ecological monitoring and complex diplomatic negotiations over final remediation between Spain and the United States.