The Air Force said it couldn't happen. A declassified memo said otherwise.

January 24, 1961. Just after midnight.
Near Faro, North Carolina, outside Goldsboro.

Seymour Johnson Air Force Base ran bombers around the clock. This was the shape of the Strategic Air Command's airborne alert program, the one the crews called Chrome Dome. At any given hour, somewhere over the United States or the Atlantic, a B-52 Stratofortress loaded with thermonuclear weapons was already in the air, flying long oval patterns for hours at a stretch, so that if the order ever came, part of the strike force would already be off the ground and past the reach of a first strike. Crews flew the pattern, refueled from tankers in midair, flew it some more, and came home to sleep before doing it again a few days later. By January 1961 this had been going on for years. At Goldsboro it was simply what the base did, the way a mill town runs its shifts.

On the night of January 23 into the 24th, a B-52G took off from Seymour Johnson on a scheduled alert mission. Eight men were aboard. In the bomb bay, secured for a flight that was never supposed to end anywhere but back on that runway, were two Mark 39 thermonuclear bombs.

The mission called for a rendezvous with a tanker partway through the flight, a routine transfer of fuel from one aircraft to another at altitude, something crews did so often it barely registered as an event. During the approach to the tanker, the bomber's own crew found a problem: fuel was leaking from the right wing, faster than it should have been. Command was notified. The decision came back to abort the refueling and bring the aircraft home before the leak cost it the fuel it needed to land.

The leak did not stop on the way back. The wing kept losing fuel it could not afford to lose, and the imbalance put a strain on the airframe that the airframe had not been built to carry for long. Just after midnight, as the bomber came down toward Seymour Johnson, the right wing gave out. It separated from the aircraft in the air. The B-52 broke apart, low enough that the wreckage came down within a few miles of the base, scattering itself and its cargo across the fields and swampland outside the town.

Five of the eight men aboard reached the ground alive. The other three did not.

The two bombs came off the disintegrating aircraft the way anything unsecured comes off an airplane that has just stopped being an airplane, which is to say at random, riding whatever piece of the wreckage happened to be carrying them when the structure let go. That mattered more than it would have on almost any other kind of aircraft, because a Mark 39 sitting in a B-52's bomb bay is wired into the same electrical system that arms it for release. The airplane had just torn itself into several unrelated pieces of falling metal, and each piece still had a say in which switches got thrown on the way down.

The first bomb rode a section of wreckage that still had power running through it in something close to the sequence a real bomb release would follow. Its parachute deployed, the same canopy that was meant to slow a live weapon dropped from low altitude long enough for the releasing aircraft to get clear before detonation. The bomb drifted down under that parachute and came to rest hanging in the branches of a tree in a field near the community of Faro, a few miles outside Goldsboro. It did not go off.

The second bomb had no parachute open above it. It fell free and struck the ground at the speed of a bomb in an uncontrolled drop, in a wet field not far from the first. The impact set off the weapon's conventional high explosive, the charge whose job in an actual detonation is to compress the nuclear core to critical mass. That charge went off on its own, without anything nuclear following it, and left a crater in the soil. Pieces of the bomb, including the component that held its uranium, drove themselves down into the wet ground and stayed there.

Crews from Seymour Johnson reached both sites before the sun came up. The tree bomb came down largely in one piece, and once ordnance specialists worked through its arming sequence switch by switch, they found something that did not make it into anything handed to a reporter. Of the several independent safety devices built into the weapon specifically to prevent this kind of accident from ending in a nuclear detonation, most had already moved into or through the armed position sometime during the aircraft's breakup, the way a car's wiring can do strange things in a wreck. One device stood between that bomb and a full-yield detonation over Wayne County, North Carolina: the ready safe switch, and on this particular bomb, on this particular night, it happened to be resting in the safe position. No one on the ground had put it there on purpose. It had landed there by the mechanics of the crash itself.

At the crater, recovery did not go well. The water table in that part of North Carolina sits close to the surface, and the excavation crews trying to reach the rest of the second bomb kept hitting groundwater that refilled the hole faster than it could be pumped dry. The dig went on for weeks before it was called off, the uranium-bearing component still unrecovered, sitting somewhere below the water line. The Air Force secured a permanent easement over the property, barring anyone from digging there again, and has held that easement ever since.

What the public got, at the time and for a long while after, was a version built around reassurance. Officials confirmed a crash and confirmed there had been nuclear weapons aboard, and paired that with the position, repeated whenever the question came up, that American weapons carried enough independent safeguards that no plausible accident could result in an actual detonation. That was the line for years, told to reporters, told to Congress when it asked, told as a settled fact rather than an estimate.

Inside the weapons program, the estimate looked different. In 1969, a safety engineer at Sandia National Laboratories, the lab responsible for the non-nuclear firing and safety components of American nuclear weapons, revisited the Goldsboro accident with eight more years of analysis behind him. His name was Parker F. Jones. Writing for an internal audience that was never meant to include the public, Jones concluded that a single low-voltage switch, the kind of switch found in ordinary household equipment, had been the only thing standing between the United States and a weapon detonating on its own soil. He stated it as an engineering finding, not a scare, and moved on to his next paragraph.

That report sat classified for more than four decades. It came out in 2013, after a journalist researching the history of American nuclear weapons accidents filed a Freedom of Information Act request and got it released. Parker Jones's memo, written in 1969 for a handful of colleagues, became public record forty-four years after the crash it described, and well after Jones himself had died.

No one was ever charged over what happened outside Goldsboro. The accident board that investigated the crash traced it to the fuel leak and the structural failure that followed, a maintenance and materials finding rather than a case against any person. The Chrome Dome program continued for several more years, through further accidents at other bases and other countries, before the Air Force ended it in 1968, after a B-52 carrying nuclear weapons crashed near Thule Air Base in Greenland.

The tree bomb was recovered, disarmed, and returned to the ordinary weapons stockpile system, one more unit pending eventual disposal like any other.

The uranium-bearing piece of the second bomb was never recovered. It remains buried in the field outside Faro, underground, which the government still controls through the easement it took out in 1961. No health effects among nearby residents have ever been publicly documented.

In 2012, the state of North Carolina put up a historical marker along the highway near Eureka, not far from where the bombs came down, with a few printed lines for anyone who pulls over to read it. The switch that mattered is still rated the same way it was in Parker Jones's report.