The main problem with fire in an inside tank was in a roll over accident.The gas cap would shear off and gas would run out right where all the sparks were being generated from the cab rubbing on the pavement. Fire would come right up through the broken window into the cab. A couple of kids were burned to death near here a few years ago. Their injuries were minor but they could'nt get out fast enough. That said, I still have one truck with the tank in the cab.