The Day We Lost the H-Bomb: Cold War, Hot Nukes, and the Worst Nuclear Weapons Disaster in History

The exact inner workings of the Mark 28 are still classified, but it is possible to make some educated guesses about what lay inside. The bomb contained a fission trigger, which was a plutonium core surrounded with reflective material (probably uranium) to contain the explosion, and high explosive to start the implosion. This “primary,” as it was called, was probably about a foot in diameter and vaguely resembled a soccer ball. Like a soccer ball, the primary had a pattern of twenty hexagons and twelve pentagons, forming a sphere. Each of these hexagons or pentagons, designed to focus explosive power inward, was called a lens. Each lens was filled with high explosive and attached to a detonator wire. When detonated simultaneously they imploded, crushing the plutonium inside into a critical mass and igniting a fission explosion.

If the high explosive didn't detonate simultaneously, the plutonium would not be evenly compressed; there would be no critical mass and no nuclear explosion. Such a precise detonation could happen only when a bomb was armed — not the case with the bombs of Palomares. This is not to say that detonating the high explosive is a good thing. Plutonium is highly radioactive, and an explosion could scatter it for miles.

The rest of the Mark 28 bomb contained a secondary fusion bomb and probably a third fission bomb to keep the fusion reaction moving. All the various sections (as well as batteries and electronics) were probably supported by a dense plastic foam. When the primary implodes, the fission emits radiation that causes a series of reactions. In a few hundred microseconds or less, the massive energy crushes a cylinder full of deuterium, sometimes called the “pencil.” Inside the pencil, a plutonium “spark plug” explodes, releasing X-rays and gamma radiation. The radiation shoots outward, reacting with the plastic foam, which swells or explodes and further crushes the deuterium in the pencil. All this complicated engineering implodes and explodes within the blink of an eye, and the result is nuclear fusion. The Mark 28 was a deadly weapon and top secret — not the type of thing the United States wanted to leave lying around southern Spain, where anybody could see it, photograph it, or pick it up and cart it away.

As the sun rose on January 18, the Air Force searchers in Palomares began to gather for the day's work. For everyone, it had been a long night.

After landing at San Javier, General Wilson had taken a small party and driven about two hours up the coast to visit Rooney, Messinger, and Wendorf in Aguilas. He spoke to them about the accident and arranged for their transportation to Torrejón. Afterward, Wilson and his men drove back to Palomares and convened at the B-52 tail section. The general took a quick look around and listened to the early reports. The charred remains of the dead airmen had been brought to Cuevas de Almanzora, the local government seat. In Cuevas, a priest had said a Mass for the men. Later in the afternoon, authorities laid the wooden caskets in the reception room of the town hall and surrounded them with burning candles. Townspeople filed by to pay their respects.

That evening, General Wilson drove to Cuevas to claim the bodies. Somehow, the townspeople and guardias civiles who had gathered the remains had determined that there were eight bodies, rather than seven, and distributed the remains into eight coffins. Wilson met with the authorities in Cuevas and explained that there had been eleven airmen on the planes and that four had survived, leaving seven deceased. After some bureaucratic struggle, the Spaniards allowed Wilson to sign for seven bodies. Late that night, a baker's delivery van — the only appropriate vehicle available — carried the remains to San Javier. From there they were flown to Torrejón for identification and then home to America.

After completing this somber duty, General Wilson and his entourage drove back to Palomares to meet with the rest of the disaster control team. Most of the team — and, it seemed, most of the villagers-had crammed into a bar in the center of town. Amid the clamor, Wilson sorted through the day's good and bad news. The good news was pretty good: searchers had found one bomb intact with no leaking radiation. There seemed to be no one hurt in the village, and certainly no widespread death and destruction. The locals seemed willing to help, and at least thirty-eight guardias civiles had already arrived to aid with searching and security.

The bad news: seven men were dead; two planes lay shattered across the Spanish countryside; there were no accurate maps of Palomares; there was no secure communication link to Torrejón; and there were still three bombs missing.