A U.S. B-52 Dropped Four Nuclear Bombs on Spain. The Men Sent to Clean It Up Faced a Different Battle

Key Points:

• On January 17, 1966, a US Air Force B-52 carrying four thermonuclear weapons broke up mid-air over Southern Spain after colliding with a KC-135 tanker during aerial refueling near Palomares, resulting in three weapons falling on land and one into the Mediterranean Sea.
• Two of the weapons on land detonated their conventional explosives, releasing plutonium and prompting a large cleanup operation involving over 1,600 Air Force personnel, some of whom later reported health issues believed to be linked to radiation exposure despite official assurances of minimal risk.
• The missing fourth bomb was recovered from the Mediterranean Sea after an 11-week search by the US Navy using ships and a deep-sea submersible, with the weapon found intact and its safety switch still engaged.
• The Palomares accident occurred during Operation Chrome Dome, a program of continuous airborne nuclear alert missions, and influenced subsequent nuclear safety protocols, including the development of radiation detection instruments used in the 1968 Thule Air Base crash cleanup.
• Following the Thule accident and lessons learned from Palomares, Operation Chrome Dome was terminated in 1968, shifting US nuclear bomber alert status from airborne patrols to ground-based readiness.