A classified nuclear accident from 1957 remained hidden from public knowledge for nearly 30 years, when a B-36 bomber accidentally dropped a Mark 17 hydrogen bomb near Albuquerque, New Mexico.
On May 22, 1957, while landing at Kirtland Air Force Base, First Lieutenant Robert Carp was removing a safety pin when the massive 15-megaton hydrogen bomb unexpectedly fell through the aircraft's bomb bay doors.
The incident could have been catastrophic, but fortunately the bomb's plutonium core had been removed beforehand as a safety precaution during transport. However, when the weapon struck the ground, its conventional explosives detonated, creating a 25-foot wide crater in the desert. The only reported casualty was one unfortunate cow.
At the time, the Air Force concealed the true nature of the accident, releasing a cover story about a conventional "service bomb." The reality of the nuclear weapon incident remained classified until 1986 when the official reports were finally declassified.
The accident site, located in an empty desert area known as Mesa del Sol, remains accessible to the public today though it carries no markers or identification. Small fragments of the weapon can still be found scattered around the impact zone.
By the end of 1957, the Air Force had phased out all Mark 17 bombs from its arsenal as the B-36 bomber was replaced by the B-52, and more compact hydrogen bombs became available. Today, visitors can view a Mark 17 bomb casing on display at the Museum of Nuclear History and Science in Albuquerque, just miles from where the accident occurred.
This "Broken Arrow" incident serves as a sobering reminder of the risks involved in handling nuclear weapons during the height of the Cold War era.