Document Excerpt: On January 16, 1961 a US fighter jet sat on the tarmac prepared to defend the continental United States against a possible Soviet nuclear-armed bomber attack. As part of its arsenal, this jet carried a 1.7 kiloton nuclear tipped air-to-air missile as it waited on quick reaction alert. While many jets had sat on such quick reaction alerts before, this day was different. During a routine "engine run up," the underwing fuel tank accidentally dropped off; the resulting leaking fuel caught fire, badly scorching and blistering the nuclear warhead. This was far from the only accident involving on-alert nuclear weapons in the United States. A year before a long-range nuclear tipped cruise missile had been destroyed by fire while on alert. That time, the nuclear warhead was completely destroyed and the plutonium pit melted. Unfortunately the history of deployed US nuclear weapons has many other examples where a nuclear weapon might have detonated causing widespread destruction.