That is not true. In fact, one of the findings of the TWA 800 investigation was that the military had already identified there was a problem regarding high temperatures in the fuel tanks of its E-4B (747) aircraft. The military adjusted its procedures to minimize the potential hazard. Boeing did not pass that info to the civilian world. It may have made a difference.
Can you present the thermodynamic data showing the explosive limits -- air / fuel/temperature/pressure ?