Nuclear weapons were held in a B-47 by two systems: a complicated but reliable pneumatically powered catch that could be operated by the crew and a manually inserted steel locking pin. With the locking pin in place, it was impossible to drop the weapon. With the pin out, the crew could jettison the weapon almost immediately. By regulation, the locking pin was to be out for landing and takeoff.

The Strategic Air Command (SAC) was founded in 1946 to provide a force capable of nuclear retaliation against the Soviet Union. In October 1948, Curds LeMay took over as commander. During World War II he had earned the unaffectionate title Iron Ass for what his airmen considered a fanatic devotion to training. In his bombing campaign against Germany, LeMay had developed a scheme of flying bombers in tight formations over enemy territory, thus permitting them to protect one another from enemy fighters. To improve bombing accuracy, he came up with the idea of “lead” navigation. Selected crews became highly familiar with the approach routes to specific targets, and the entire tightly grouped formation would drop its bombs when the lead plane did. LeMay’s revolutionary tactics became standard U.S. practice; but flying large bombers in tight formations for hours was not a natural act, and it took a great deal of work to develop the concentration to do it routinely.

Not surprisingly, LeMay brought the deep faith in training he developed during World War II to his new job at SAC. Virtually every aspect of the routines he devised was quantified, with points awarded for performance counting heavily in promotions. The results of particularly important activities, such as simulated combat missions like “Snow Flurry,” were relayed electrically to SAC headquarters, where senior officers, including the commander himself, reviewed them aggressively. If a mission did not go well, the local commander might receive a direct message from LeMay demanding a personal briefing on the reasons. Local

The nuclear weapon that landed on Mars Bluff was a Mark 6 30-kiloton bomb, an older fission (nonhydrogen) design considered highly reliable. It weighed 7,600 pounds, was 10 feet 8 inches long, and had a maximum diameter of 61 inches. Starting at eight o’clock on the morning of March 11, a specialized two-man loading crew took one hour and seven minutes to put the bomb into Air Force 531876A. When the loading team had trouble engaging the steel locking pin, they called the weapons release systems supervisor for assistance. He took the weight of the weapon off the plane’s bomb-shackle mechanism, put it onto a sling, and then “jiggled” the pin with a hammer until it seated. The bomb was put back on the shackle, and preflight checks continued. But neither the bomb-loading crew nor the aircrew ran the locking pin through its engage/disengage cycle with the bomb’s weight on the shackle. For the crew to receive maximum points for its unit under the ground rules, all preflight checks had to be finished by 10:30. It is difficult not to suspect that institutional pressure to gain points led to omission of this step.

After the bomb had been loaded and the preflight checks completed, the crew went to briefings on weather and operations, had lunch, and returned to the plane about 2:40. At 3:42 Captain Koehler started his engines. At 3:51, as required by regulations, co-pilot Woodruff rotated his seat to face aft and pulled the lever to disengage the locking pin from the nuclear weapon. It could now be dropped instantly in case of an emergency. At 3:53 the plane took off to join three other B-47s for a formation flight to Europe. When the B-47 reached an altitude of 5,000 feet, Woodruff again rotated his seat, this time to re-engage the locking pin. He worked the locking lever unsuccessfully for five minutes as the B-47 climbed to 15,000 feet to join the three other aircraft. At this point, the crew knew it had a problem. The pilot told the bombardier, Captain Kulka, to go into the bomb bay to try to seat the locking pin by hand. This was not a trivial decision; the bomb bay was not pressurized, so the entire plane had to be depressurized. Because the plane was at 15,000 feet, the crew had to go on oxygen. Further complicating matters, the entrance to the bomb bay was so narrow that a parachute could not be worn into it.

The task was doomed from the start; later testimony indicated Kulka had no idea where to find the locking pin in the large and complicated bomb-release mechanism. After a tense 12 minutes searching for the pin, the bombardier decided, correctly, that it must be high up in the bomb bay and invisible because of the curvature of the bomb. A short man, he jumped to pull himself up to get a look at where

In case of an unscheduled bomb drop, Air Force regulations required the crew to immediately notify its base by a special coded message. Because the procedure had never been used, the operations center at Hunter Air Force Base did not recognize the strange incoming message. As a final indignity, the pilot was reduced to radioing an open, uncoded message to the civilian tower at the Florence airport six miles west of Mars Bluff asking them to advise Hunter by telephone that aircraft 53-1876A had lost a “device.” The plane then turned back to photograph the site with its aerial camera. This was not difficult; the plume of smoke was easily visible from nearly three miles up. Because the plane could not dump fuel, it descended to the denser air at 6,000 feet, where it circled for 2 hours and 26 minutes before landing uneventfully.

The concussion from the explosion injured all five members of the Walter Gregg family (Mrs. Gregg was sewing in the front parlor, and her son, Walter Junior, was standing next to his father in the toolshed) as well as their cousin, Ella Davies. They were taken to the Florence hospital, where Ella, who had 31 stitches, was kept overnight and the others released. Although the Greggs certainly knew their problems stemmed from some sort of explosion, it was not until that evening at the hospital that Walter Gregg learned it was caused by a U.S. Air Force bomb.

The Florence Morning News knew the real cause of the problem several hours before Gregg did. The call came into the paper just before 5:00 P.M. and was taken by Thom Andersen, who would one day be the News ’s managing editor but who was then a cub sportswriter. He was the only reporter in the newsroom; the others were down the street at the courthouse attending a trial, and Anderson went there to tell his superiors about the explosion. They speculated that an external fuel tank had dropped and told him to check on it in the morning. Anderson, however, was not convinced,

Anderson quickly discovered the actual nature of the explosion, the photographer got pictures of the crater and the wreckage of the house, and the next day the Morning News had four articles on the accident, with photographs, on its front page—substantially better coverage than The New York Times was able to give the event. In addition to the thrill of covering what was certainly the biggest story in the area in a decade, Anderson was flattered to field telephone inquiries about the incident from the foreign press. Things got even better for him when he received a number of checks from those news organizations, a pleasure previously unknown to Florence cub sports reporters.

The reception of the B-47 crew back at their base was perhaps more difficult than their flight. By regulation, all crew members on missions carried loaded pistols. As the crew clambered out of the aircraft, they were met by armed air police, who relieved them of their weapons and took them to a room in the base operations center with mattresses hastily arranged on the floor. They were told they would be obliged to stay here “at least overnight”; they were not allowed to contact their families or anyone else. The fear seems to have been that they had dropped the bomb deliberately. Later that evening, General LeMay, who was by then vice chief of staff of the Air Force, called Captain Koehler directly to get a telephone briefing on what had happened. LeMay, perhaps the only operational commander in the Air Force who had actually performed maintenance on his bombers, understood Koehler’s explanation, and the crew was released.

The accident was featured prominently in the national and international press. The New York Times’s columnist Harrison Salisbury commented, and the prime minister of Great Britain reassured the House of Commons. Overall, what is surprising is that coverage essentially disappeared after three days, and despite conflicting statements from the Air Force, the press did not investigate whether radioactive material had been released into the atmosphere. This casual acceptance stands in stark contrast to the media frenzy that accompanied the accident at Three Mile Island 21 years later. As it turned out, classified Air Force radiation studies released in 1997 indicate that radiation after the Mars Bluff explosion was barely above background levels. As was the rule in peacetime, the fissionable nuclear core of the weapon was stored elsewhere in the aircraft in what was called “the birdcage.” In a war situation, the crew would have transferred the nuclear core from the birdcage to the bomb bay and inserted it into the bomb.