OTD 70 years ago, a B-29 ferrying an unarmed Mark-4 atomic bomb (no plutonium capsule) to Guam for potential use in the Korean War crashed and burned attempting an emergency landing 5 minutes after takeoff from Fairfield-Suisun AFB, CA, killing 12 crew/passengers and injuring 8. 
~20 min. after the crash, the Mark-4's 5,000 lbs. of high explosives detonated, killing 7, injuring 173, destroying all the base's fire trucks, and severely damaging a trailer park. USAF claimed the explosion—which was heard 30 miles away—was caused by conventional 500-lb. bombs.
Among those killed in the crash was highly-decorated Brigadier General Robert F. Travis, who was sitting in the cockpit that night in command pilot capacity and serving as a high-level escort for the aircraft's secret cargo. Fairfield-Suisun AFB was renamed in his honor in 1951.
This Aug. 7, 1950, New York Times report on the accident repeats the Air Force's lie the B-29 was on a training mission and makes no mention it carried an A-bomb with a variable yield of 1-31 kilotons, one of nine Pres. Truman had ordered deployed to Guam. timesmachine.nytimes.com/timesmachine/1…
In January 1958—after revelations that SAC bombers were carrying nuclear weapons in and out of the United Kingdom set off debates there—the US Air Force sought to reassure people by revealing this accident did not result in a nuclear explosion (although it provided no details).
