The Palomares incident, also widely known as the 1966 Palomares B-52 crash, represents a pivotal and concerning event in nuclear history. This dramatic accident unfolded on 17 January 1966, amidst the heightened tensions of the Cold War. A B-52G bomber, a key asset of the United States Air Force's Strategic Air Command (SAC), was engaged in a routine mid-air refueling operation. These continuous airborne alert missions, often codenamed "Operation Chrome Dome," were a critical component of nuclear deterrence, ensuring that nuclear-armed bombers were constantly in the air, ready to strike if necessary.

During this vital procedure, at an altitude of approximately 31,000 feet (9,450 meters) over the Mediterranean Sea, just off the coast of Spain, the B-52G collided with its KC-135 Stratotanker. The KC-135, a specialized aerial refueling aircraft, was instantly destroyed as its substantial fuel load ignited, tragically claiming the lives of all four crew members aboard. The B-52G bomber suffered a catastrophic structural failure, breaking apart in the sky. Of its seven-person crew, three perished in the devastating crash.

The Nuclear Cargo and Immediate Impact

At the time of the collision, the B-52G was carrying four B28FI Mod 2 Y1 thermonuclear bombs. These were sophisticated hydrogen bombs, designed for immense destructive power, far exceeding that of atomic bombs. All four of these powerful weapons were dislodged from the aircraft and fell towards the earth's surface.

Contamination on Land

Three of the four thermonuclear bombs impacted land in the vicinity of Palomares, a small fishing village nestled within the municipality of Cuevas del Almanzora, Almería, Spain. The non-nuclear, conventional explosives within two of these weapons detonated upon impact with the ground. While these detonations did not trigger a nuclear chain reaction, they had a severe consequence: the dispersal of highly radioactive plutonium from the weapons' core. This resulted in the contamination of an estimated 0.77-square-mile (2 km²) area. Plutonium is an alpha-emitting radionuclide, extremely hazardous if inhaled or ingested due to its long half-life and potential to cause various cancers. This incident was immediately classified as a "Broken Arrow," a term used by the U.S. Department of Defense to denote an accident involving nuclear weapons that does not pose a risk of nuclear detonation but involves the unintentional launching, firing, detonating, theft, or loss of a nuclear weapon.

The Elusive Fourth Bomb

The fourth B28 thermonuclear bomb, however, plunged into the depths of the Mediterranean Sea. Its recovery became a critical and complex endeavor, initiating one of the most extensive underwater search and recovery operations in history. The search, which involved numerous U.S. Navy vessels and advanced submersibles like the DSV Alvin, lasted for two and a half months. The bomb was eventually located intact and successfully recovered from a depth of 2,850 feet (869 meters), thanks in part to crucial information provided by a local fisherman, Francisco Simó Orts.

Aftermath and Enduring Legacy

The Palomares incident triggered a massive and unprecedented cleanup effort, known as "Operation Broom." Over 1,400 tons of contaminated soil and vegetation were meticulously removed from the affected areas in Palomares. This material was subsequently shipped to the Savannah River Site in the United States for long-term storage and disposal. The cleanup was a testament to the extensive logistical challenges posed by nuclear contamination.

The accident also had significant diplomatic repercussions between the United States and Spain. To quell public fears and demonstrate the safety of the area after the initial cleanup, the then U.S. Ambassador to Spain, Angier Biddle Duke, famously took a swim in the waters off Palomares with Manuel Fraga Iribarne, Spain's Minister of Information and Tourism, on March 25, 1966. Despite these efforts, the incident left a lasting legacy of environmental monitoring, health studies among the local population, and ongoing discussions regarding remaining contamination. Subsequent agreements, such as the 2015 joint statement between Spain and the U.S., highlighted continued commitment to addressing residual issues and further remediation efforts in the area, underscoring the long-term nature of nuclear incident management.

Frequently Asked Questions About the Palomares Incident

What was the primary cause of the Palomares B-52 crash?

The accident was caused by a mid-air collision between a U.S. Air Force B-52G bomber and a KC-135 Stratotanker during a routine aerial refueling operation.

How many nuclear bombs were involved in the Palomares incident?

Four B28FI Mod 2 Y1 thermonuclear (hydrogen) bombs were aboard the B-52G at the time of the crash.

Was there a nuclear detonation at Palomares?

No, there was no nuclear detonation. However, the conventional (non-nuclear) explosives in two of the bombs detonated upon impact, dispersing radioactive plutonium and causing contamination.

What is a "Broken Arrow" incident?

A "Broken Arrow" is the U.S. Department of Defense's classification for an accident involving a nuclear weapon that does not involve a risk of nuclear detonation, but includes scenarios like accidental launching, firing, detonation of non-nuclear components, theft, or loss of a nuclear weapon.

How was the fourth bomb recovered from the sea?

The fourth bomb was recovered from the Mediterranean Sea after an extensive two-and-a-half-month search operation involving specialized deep-sea submersibles, including the DSV Alvin, and assistance from a local fisherman.

What were the long-term consequences of the Palomares incident?

The incident led to a massive cleanup effort, long-term environmental monitoring, health studies for affected populations, and ongoing diplomatic discussions between Spain and the U.S. regarding residual contamination and future remediation.