How the US dropped four nuclear bombs on Spain in 1966

In 1966, the remote Spanish village of Palomares found that the “nuclear age had fallen on them from a clear blue sky”. Two years after the terrifying accident, BBC reporter Chris Brasher went to find what happened when the US lost a hydrogen bomb.

On 7 April 1966, almost 60 years ago this week, a missing nuclear weapon for which the US military had been desperately searching for 80 days was finally found. The warhead, with an explosive power 100 times that of the bomb dropped on Hiroshima, was carefully winched from a depth of 2,850ft (869m) out of the Mediterranean Sea and delicately lowered onto the USS Petrel. Once it was on board, officers painstakingly cut into the thermonuclear device’s casing to disarm it. It was only then that everyone could breathe a sigh of relief – the last of the four hydrogen bombs that the US had accidentally dropped on Spain had been recovered.

“This was not the first accident involving nuclear weapons,” said BBC reporter Chris Brasher when he reported from the scene in 1968. “The Pentagon lists at least nine previous accidents to aircraft carrying hydrogen bombs. But this was the first accident on foreign soil, the first to involve civilians and the first to excite the attention of the world.”

This terrifying situation had come about because of a US operation code-named Chrome Dome. At the beginning of the 1960s, the US had developed a project to deter its Cold War rival, the Soviet Union, from launching a pre-emptive strike. A patrol of nuclear-armed B-52 bombers would continuously criss-cross the skies, primed to attack Moscow at a moment’s notice. But to stay airborne on these long looping routes, the planes needed to refuel while in flight.

On 17 January 1966, one such bomber was flying at a height of 31,000ft (9.5km) over the Almería region of southern Spain, and attempted a routine air-to-air refuelling with a KC-135 tanker plane. “I believe what happened was the bomber was closing at a too-high rate of closure speed and he didn’t stabilise his position,” US Maj Gen Delmar Wilson, the man in charge of dealing with the catastrophic accident, told Brasher, “with the result that they got too close and collided.”

The B-52 bomber’s impact with the refuelling plane tore it open, igniting the jet fuel the KC-135 was carrying and killing all four of the crew onboard. The ensuing explosion also killed two men in the B-52’s tail section. A third managed to eject, but died when his parachute did not open. The other four members of the bomber’s crew successfully bailed out of their burning plane before it broke apart and fell to earth, raining down both flaming aircraft fragments and its lethal thermonuclear cargo onto the remote Spanish village of Palomares.

The huge fireball was seen a mile away. Thankfully, it did not trigger a nuclear explosion. The bomber’s warheads were not armed and had built-in safeguards to prevent an unintended atomic chain reaction. But the thermonuclear devices did have explosives surrounding their plutonium cores as part of the triggering mechanism. In the event of an accident, the bombs had parachutes attached to them designed to cushion the impact on landing and prevent radioactive contamination. And indeed, one undetonated bomb did land safely in a riverbed and was recovered intact the following day. Unfortunately, two of the plummeting nuclear bombs’ parachutes failed to open.

That morning, Spanish farmer Pedro Alarcón was walking to his house with his grandchildren when one of the nuclear bombs landed in his tomato field and blew apart on impact. “We were blown flat. The children started to cry. I was paralysed with fear. A stone hit me in the stomach, I thought I’d been killed. I lay there feeling like death with the children crying,” he told the BBC in 1968.

The other hydrogen bomb also exploded when it hit the ground near a cemetery. These dual blasts created vast craters and scattered highly toxic, radioactive plutonium dust across several hundred acres. Burning aircraft debris also showered the Spanish village. “I was crying and running about,” a villager called Señora Flores told the BBC in 1968. “My little girl was crying, ‘Mama, Mama, look at our house, it is burning.’ Because of all the smoke I thought what she said must be true. There were a lot of stones and debris falling around us. I thought it would hit us. It was this terrific explosion. We thought it was the end of the world.”

Once the news that the bomber had come down with nuclear weapons aboard reached US military command, a huge operation was launched. At the time of the disaster, Capt Joe Ramirez was an US Air Force lawyer stationed in Madrid. “There were a lot of people talking, there was a lot of excitement in the conference room. Everyone kept talking about a ‘broken arrow’. I learnt then that ‘broken arrow’ was the code word for a nuclear accident,” he told BBC’s Witness History in 2011.

US military personnel were scrambled to the area by helicopter. When Capt Ramirez arrived in Palomares, he immediately saw the devastation and chaos wrought by the accident. Huge pieces of smoking wreckage were strewn all over the area – a large part of the burning B-52 bomber had landed in the school’s yard. “It’s a small village but there were people scrambling in different directions. I could see smouldering debris, I could see some fires.”

Despite the carnage, miraculously no one in the village was killed. “Nearly 100 tonnes of flaming debris had fallen on the village but not even a chicken had died,” said Brasher. A local school teacher and doctor climbed up to the fire-scarred hillside to retrieve the remains of the US airmen who had been killed. “Later still, they sorted the pieces and the limbs into five coffins, an act that was to cause a certain amount of bureaucratic difficulty when the Americans came to claim only four bodies from that hillside,” said Brasher.

Three of the B-52 crew who managed to eject landed in the Mediterranean several miles off the coast and were rescued by local fishing boats within an hour of the accident. The fourth, the B-52 radar-navigator, ejected through the plane’s explosion, which left him badly burned, and was unable to separate himself from his ejection seat. Despite this, he managed to open his parachute and was found alive near the village and taken to hospital.

However, this still left the problem of locating the plane’s deadly nuclear payload. “My main concern was to recover those bombs, that was number-one priority,” Gen Wilson told the BBC in 1968.

“The first night, the Guardia Civil [the Spanish national police force] had come to the little bar in Palomares, and that was about the only place that had electricity. And they had reported what they considered to be a bomb, so we immediately despatched some of our people to this riverbed which is not far from the centre of town, and, in fact, it was a bomb, so we placed a guard on that. And then the next morning, at first daylight, we started conducting our search, and I believe it was something in the order of 10am or 11am the following morning, we located two other bombs.”

This accounted for three of the nuclear bombs, but there was still one missing. By the next day, trucks filled with US troops had been sent from nearby bases, with the beach in Palomares becoming a base for some 700 US airmen and scientists urgently trying to contain any radioactive contamination and locate the fourth warhead.

“The first thing that you could see as the search really got underway in earnest was Air Force personnel linking up hand-by-hand and 40 or 50 people in a line. They would have designated search areas. There were some people with Geiger counters who started arriving, and so they started marking off the areas which were contaminated,” said Capt Ramirez in 2011. When US personnel registered an area contaminated with radiation, they would scrape up the first three inches of topsoil and seal it in barrels to be shipped back to the US. Some 1,400 tonnes of irradiated soil ended up being sent to a storage facility in South Carolina.

Both the US and Spain, which at the time was under the brutal rule of Francisco Franco’s military dictatorship, were keen to downplay the devastating accident. Franco was especially worried that radiation fears would hurt Spain’s tourism industry, a major source of revenue for his regime. In an effort to reassure the local population and the wider world that there was no danger, the US Ambassador to Spain, Angier Biddle Duke, would end up taking a swim in the sea off Palomares coast in front of the international press just weeks after the accident.

But despite hundreds of US personnel conducting an intensive and meticulous search of the surrounding area for a week, they still couldn’t find the fourth bomb. Then Capt Ramirez spoke to a local fisherman who had helped rescue some of the surviving airmen who had splashed down in the sea. The fisherman kept apologising to Capt Ramirez for not being able to save one of the US flyers, whom he thought he had witnessed drifting down into the depths. 

Capt Ramirez realised that the fisherman could have actually seen the missing nuclear bomb. “All the bodies had been accounted for, I knew that,” he said. The search then quickly shifted to the Mediterranean Sea, with the US Navy mobilising a flotilla of more than 30 ships, including mine-sweepers and submersibles, to scour the seabed. The exploration of miles of ocean floor was both technically complicated and a very slow process, but after weeks of exhaustive searching, a newly developed deep-diving vessel, Alvin, finally located the missing bomb in an underwater trench.

Nearly four months after it was first lost, the warhead was finally made safe and back in US hands. The next day, despite the secrecy with which the US military had surrounding its nuclear arsenal, it took the unusual step of showing the bomb to the world’s press. Ambassador Duke reasoned that unless people saw the bomb for themselves, they would never feel certain that it had actually been recovered.

Almost six decades later, the incident still casts a long shadow over the Almería region. The US clean-up operation managed to miss some areas of contamination, and the US and Spain agreed to fund yearly health-checks for Palomares residents. They also promised to monitor the soil, the water, the air and local crops. But there are still some 100 acres (40 hectares) of contaminated land in Palomares that remain fenced off. And despite Spain and the US signing a mutual agreement in 2015 to clean up the area, neither has yet complied. 

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