It's serious <a href="http://www.hiisirasti.fi/index.php/terrapharmkz-c29e.pdf">terrapharm.kz</a>  One of the bombs engaged normally and was only stopped from exploding by "one simple, dynamo-technology, low voltage switch [that] stood between the United States and a major catastrophe," said Parker F Jones, a senior engineer in the Sandia national laboratories responsible for the mechanical safety of nuclear weapons cited in the previously classified documents.