From the late 1940s through the peak of the Cold War, the United States and the Soviet Union were locked in a fierce competition for military supremacy and technological advancement. This intense rivalry fueled regular weapons testing, sometimes with dangerous consequences. In 1958, one such experiment went awry in Mars Bluff, South Carolina, transforming the normally peaceful town into the scene of a startling Cold War mishap.
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
The Mk 6 nuclear bomb represented a more advanced iteration of the design that had been deployed over Nagasaki at the close of World War II. Produced between 1951 and 1955, the bomb underwent several updates and stayed in the U.S. arsenal until 1962. Over its production period, more than 1,000 Mk 6 bombs were built, each capable of delivering a wide range of nuclear yields.
As tensions mounted during the Cold War, the U.S. Air Force incorporated the Mk 6 into routine training operations. Yet these exercises were not without risk—occasionally resulting in serious accidents, known within the military as “broken arrow” incidents.
A Mk 6 nuclear bomb is dropped on Mars Bluff, South Carolina
On March 11, 1958, a Boeing B-47 Stratojet from the 375th Bombardment Squadron, part of the 308th Bombardment Wing, lifted off from Hunter Army Airfield in Georgia. The flight was part of Operation Snow Flurry, a training mission involving mock bombing runs with waypoints in the U.K. and North Africa. Though only a drill, the tight schedule added pressure to the crew.
Before takeoff, airmen had trouble securing a Mk 6 nuclear bomb inside the bomb bay. The locking mechanism wouldn’t engage properly, so they resorted to using a sling to force a steel pin into place. After takeoff, the bomb’s restraint system disengaged as planned—but then failed to re-engage, posing a serious risk.
Captain Bruce Kulka, the navigator and bombardier, went to inspect the issue mid-flight. During his inspection, he unintentionally pulled the emergency release lever. The bomb plummeted from an altitude of roughly 15,000 to 20,000 feet. Kulka narrowly avoided falling out of the aircraft himself, managing to grab hold and pull back to safety.
Although the bomb lacked its plutonium core—meaning it couldn’t trigger a nuclear explosion—it still contained high explosives. Upon impact in the backyard of a Mars Bluff, South Carolina home, those explosives detonated. The blast obliterated a children’s playhouse built by homeowner Bill Gregg and created a 70-foot-wide crater. Gregg’s family sustained injuries, and seven nearby structures were damaged, but miraculously, no one was killed.
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.