Too Damn Close: North Carolina Nuclear Bomb ‘Could Have Detonated’

New documents show the risks of accidental nuclear explosions

Too Damn Close: North Carolina Nuclear Bomb ‘Could Have Detonated’ Too Damn Close: North Carolina Nuclear Bomb ‘Could Have Detonated’
Where would Raleigh, North Carolina, be today had a two-megaton nuclear bomb wiped it out in 1961? That almost happened—and newly-released documents show it... Too Damn Close: North Carolina Nuclear Bomb ‘Could Have Detonated’

Where would Raleigh, North Carolina, be today had a two-megaton nuclear bomb wiped it out in 1961? That almost happened—and newly-released documents show it came closer than previously thought.

The incident in question is the Goldsboro nuclear accident in North Carolina. On Jan. 24, 1961, a nuclear-armed B-52 bomber flew above the state when a fuel leak caused total loss of control.

The pilots bailed, and after descending past 10,000 feet, the bomber broke up. Its two MK.39 nuclear bombs—each with an explosive power of more than two megatons—ejected from the plane as it disintegrated. Had one of the bombs exploded, it would have destroyed Goldsboro, nearby Seymour Johnson Air Force Base and possibly taken out the city of Raleigh in the process.

According to documents from Sandia National Laboratory and obtained by journalist Eric Schlosser, the possibility of one of the bombs exploding was much greater than previously believed. These documents were detailed in Schlosser’s 2013 book Command and Control of Nuclear Weapons, and were released Monday after FOIA requests by the National Security Archives at George Washington University.

How close did those bombs come to exploding? Very, very close.

T-249 Arm/Safe Switch. Photo via the National Security Archives

Dead switch

Here’s how it happened. Each bomb carried aboard the B-52 had an arming mechanism known as the T-249 Arm/Safe Switch. This switch connected to a series of batteries and rods which powered and armed the device, and which prevented the bomb from inadvertently blowing itself up.

As the first of two bombs ejected from the disintegrating plane, the bomb activated its battery during the fall—part of the arming procedure—and deployed its parachute. The nuke hit the ground with a thud, its parachute catching in the trees. This jolted the safing pins that connected the battery to the bomb, worrying enough on its own, but the switch prevented the bomb from detonating.

“It is apparent that all components behaved in the normal manner that would be expected if the bomb were released from the aircraft with the T-249 in the safe condition,” a FOIA’d report from the Atomic Enegy Commission’s Albuquerque Operations Office concluded in February 1961.

But the second bomb never deployed a parachute. Instead, it impacted the earth at free-fall speeds, diving into the ground at a depth of 12 feet. This shook the indicator switch from safe mode … to armed mode.

“The MC-772 Arm/Safe Switch appeared to be intact when recovered from the unit, and the indicator drum indicated the switch was in the ARM position,” the report noted.

That must have been a bit shocking. But fortunately, the impact also damaged the switch’s contacts to the bomb’s high-voltage battery—meaning the battery never activated. Had those contacts not also been damaged in the fall? Boom.

“If the shock had not also damaged the switch contacts, the weapon could have detonated,” noted William Burr of the National Security Archives.

The Pentagon replaced the switch with a new mechanism after the Goldsboro incident. But it’s a stark example of the uncertainties involved with complex, dangerous weapons. A slight jolt in a different direction, and Raleigh wouldn’t be here today.

But there’s also a deeper problem. A nuclear weapon exploding on accident could lead to geopolitical miscalculation—such as senior officials mistakenly believing the country was under attack.

In addition to the incident report from Goldsboro, the National Security Archives also released a previously restricted 1987 review of nuclear safety programs. The conclusion, according to Sandia’s R. N. Brodie, was that the complexity of nuclear weapons combined with the huge number of potential “abnormal” situations means there is a “nonzero probability that it could be unintentionally detonated,” Brodie wrote.

In other words, you can make nuclear weapons safer—and you should—but you can never make them 100 percent safe.

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