A document published by The Guardian in declassified form for the first time Sept. 20th reveals that the U.S. Air Force came perilously close to detonating an atomic bomb over Goldsboro in 1961:

The accident happened when a B-52 bomber got into trouble, having embarked from Seymour Johnson Air Force base in Goldsboro for a routine flight along the East Coast. As it went into a tailspin, the hydrogen bombs it was carrying became separated. One fell into a field near Faro, North Carolina, its parachute draped in the branches of a tree; the other plummeted into a meadow off Big Daddy’s Road. Jones found that of the four safety mechanisms in the Faro bomb, designed to prevent unintended detonation, three failed to operate properly. When the bomb hit the ground, a firing signal was sent to the nuclear core of the device, and it was only that final, highly vulnerable switch that averted calamity. “The MK 39 Mod 2 bomb did not possess adequate safety for the airborne alert role in the B-52,” Jones concludes.

The Guardian – US nearly detonated atomic bomb over North Carolina — secret document

What would have happened if the fourth safety mechanism had failed? NUKEMAP 3D can provide an estimate, and it doesn’t look good.

Via Forbes:

We can take a guess courtesy of NUKEMAP 3D, a nuclear blast simulation created by science historian Alex Wellerstein. Select the location and bomb size, and the simulation will calculate and illustrate the damage using a Google Earth map. Try it yourself. Enter the location as “Goldsboro, N.C.” and set the bomb yield at 4,000 kilotons (equal to 4 megatons. NUKEMAP 3D calculates the Goldsboro bomb as a fireball incinerating everything in a radius of 1.05 miles from ground zero, a lethal radiation zone (500 rems of radiation in an instant, when no more than 100 rems over an entire year is considered safe) extending 1.84 square miles, a pressure wave of 20 pounds per square inch that would demolish concrete buildings at a distance of 2.78 miles, a 5 PSI pressure that would collapse most ordinary buildings 6.86 miles from the blast zone, and thermal radiation hot enough to start fires and cause third-degree burns 15.2 miles from the blast site. The radiation plume would stream past Delaware almost to southern New Jersey. The death toll is estimated at 60,000 (for New York City, it would be 3.8 million dead). The bomb “derived around 55% of its total yield from fission, which meant it was pretty ‘dirty’ as far as H-bombs went,” Wellerstein told me. While NUKEMAP 3D assumes the bomb would be an airburst (the preferred method of nuclear strategists who want to maximize destruction), “if it had detonated from surface contact, it would have produced significant fallout.” In that case, one shudders to think what the effects would be on U.S. agriculture.

Forbes – This Is What Happens When An H-Bomb Explodes Over North Carolina

Read the full declassified document here.