Shepperd said the United States had agreed in a Cold War-era treaty not to fly nuclear weapons. "It appears that what happened was this treaty agreement was violated," he said.
The warheads should have been removed from the missiles before they were attached to the B-52 bomber, according to military officials.
A military official told CNN there was no nuclear risk to public safety because the weapons were not armed. Officials believe that if the plane had crashed or the missiles somehow had fallen off the wings, the warheads would have remained inert and there would have been no nuclear detonation, though conventional explosive material in the warhead could have detonated.
Full story:
http://www.cnn.com/2007/US/09/05/loose.nukes/index.html
This one's a real doozy - someone dropped the ball. Even if there was no nuclear risk, "conventional explosive material in the warhead could have detonated."