Very few people know that in 1966, the U.S. military accidentally dropped four atomic bombs on Spain. Through a very large cover-up and PR effort, the U.S. has managed to keep it out of most history books, newspapers and the media, reports VICE, but what happened was a very serious incident that still has consequences 50 years later.

On January 17, 1966, a US B52 bomber crashed into a refueling aircraft in Spain's airspace, causing four atomic bombs to drop. Two of them imploded in the Andalusian town of Palomares, releasing plutonium into the soil. Parachutes were released on the other two -- one landed on the ground but did not detonate and the other landed in the Mediterranean Sea, also still intact.

Author and photographer, Professor John Howard, recently released a book titled "White Sepulchres," in which he documents the effect of this tragic incident on the people of Palomares. Prof. Howard spoke to VICE about his research on the incident, the cover-up afterwards and the on-going effects it has on the Andalusian people today.

He says that when the government loses or breaks a hydrogen bomb it's referred to as a "broken arrow." "The U.S. admit to 32 of these 'broken arrows.' Eric Schlosser, an investigative journalist, estimates 100 for the 1950s alone, and for the U.S. Air Force alone, claiming that the navy and army failed to keep track," he told VICE.

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The reason hardly anyone noticed the bomb explosions at the time is because the U.S. turned all focus to the single bomb that fell into the Mediterranean. They brought in 32 ships to retrieve it and it took them 80 days. They gave the press images of the search, shifting the focus to the one bomb that went missing in the sea, instead of the three others on land.

50 years later, the exact health risks cannot be pinpointed, but it's estimated that ten kilos of plutonium were initially spilled, and just one milligram of plutonium in your lungs is almost certain to cause lung cancer. Prof. Howard told VICE "If a kilo or two is still on the ground, then anyone could inhale it on the wind. We know plutonium is in the food chain, but ingestion isn't as severe as inhalation, which they say is a guarantee of lung cancer."

There haven't been many tests on the long-term health effects either, partly because there was a mass exodus after the incident, where 1,000 people moved out of Palomares. But there is an agricultural industry here, where migrant workers farm on the land, digging in the soil and kicking up dirt everyday, meaning they are more likely than anyone else to inhale plutonium. However, if they get cancer several years from now they might not still be in Palomares and then attribution becomes difficult.

Interestingly, a very active sex industry has sprung up in the rural area surrounding Palomares in recent years. It's a sort of haven for swingers, nudists and the LGBT community, with people coming to visit from all over Spain and internationally as well. There's even a drag club with a name that translates to "Who cares?" -- something that Prof. Howard believes is a reflection on the "we're all going to die anyway" mentality.

In visiting this potentially toxic environment, Prof. Howard says he was concerned for the risk it posed to his own health, but ultimately he felt that telling this story to the world was more important.

Top Photo: The recovered hydrogen bomb displayed on the fantail of the submarine rescue ship USS Petrel (ASR-14) after it was located by DSV Alvin at a depth of 2,500 feet (760 m)