In the years following World War II, the intensifying Cold War drove the United States and the Soviet Union into a fierce competition to develop increasingly powerful weapons. Both nations pushed forward with rapid testing and deployment, often accepting significant risks in the process. One dramatic example occurred in 1958 in the small town of Mars Bluff, South Carolina, underscoring the very real dangers tied to this high-stakes arms race.
The United States continued developing bombs after World War II
The Second World War was a harrowing conflict. The US brought it to a close in the summer of 1945 by dropping the atomic bombs Little Boy and Fat Man on Hiroshima and Nagasaki. Nonetheless, the nation continued to advance its development of newer and more powerful nuclear weapons.
Development of the Mk 6 nuclear bomb
Modeled on the atomic bomb used at Nagasaki, the Mk 6 nuclear device was developed into multiple variants and became one of the United States’ most widely produced early atomic weapons. Built between 1951 and 1955 during the early Cold War, over a thousand Mk 6s were manufactured in different configurations and explosive yields, remaining in the U.S. nuclear arsenal until 1962.
Amid escalating tensions with the Soviet Union, U.S. Air Force crews routinely conducted training missions simulating nuclear strikes, often carrying live Mk 6 bombs under realistic conditions. These exercises carried inherent danger, and several accidents occurred during the 1950s, resulting in unintended releases of nuclear ordnance—incidents the military quietly classified as “broken arrows.”
A Mk 6 nuclear bomb is dropped on Mars Bluff, South Carolina
On March 11, 1958, a Boeing B-47 Stratojet assigned to the 375th Bombardment Squadron of the 308th Bombardment Wing departed from Hunter Army Airfield as part of Operation Snow Flurry—a drill simulating bombing runs over the U.K. and North Africa. The mission began under pressure due to a tight schedule, and complications arose during pre-flight checks when the locking mechanism on a Mk 6 nuclear bomb failed to engage properly. To secure it, airmen resorted to using a sling to force a steel pin into place.
Once in the air, the restraint system released as intended but failed to reset. While investigating the issue mid-flight, Captain Bruce Kulka—serving as navigator and bombardier—accidentally triggered the emergency release lever. The bomb fell from an altitude of approximately 15,000 to 20,000 feet. Kulka narrowly avoided being pulled from the aircraft, managing to hold on and climb back to safety.
Although the weapon lacked its plutonium core and could not produce a nuclear explosion, it still carried conventional high explosives. Upon impact in the backyard of a home in Mars Bluff, South Carolina, the blast destroyed a children’s playhouse, left a crater roughly 70 feet wide, injured members of the Gregg family, and damaged several nearby buildings. Remarkably, no fatalities occurred.
Reaction to the Mars Bluff Incident
Surprisingly, no one suffered serious injuries from the blast because the Mk 6 bomb’s nuclear core was stored separately in the B-47 aircraft. The explosion was caused only by the TNT inside the bomb. If a full-scale nuclear detonation had occurred, the destruction would have been devastating.
Military authorities arrived at the scene shortly after the incident. The Gregg family, who lost everything in the explosion, sued the Air Force and granted $54,000 in compensation. Despite their hardship, Bill Gregg remained optimistic, later telling a local newspaper, “I’ve always wanted a swimming pool, and now I’ve got a hole for one at no cost.”
Legacy of the Mars Bluff Incident
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The near-disaster became known as the “Mars Buff Incident,” and received local and international coverage. It also contributed to a change in the way the Air Force ran its training exercises going forward, especially since accidents like it were more common than the military would have liked to admit. Shortly after, the branch stopped carrying nuclear bombs during training missions.