Sure. But it took a hell of a lot more than a mere spark to get that boom. That’s my point.
Weren’t no spark that set off that explosion, unless you consider a warhead to be a spark.
I've cut open a bunch of UST’s that had contained jet fuel, fuel oil, diesel, gasoline etc. Gasoline is definitely the most volatile and you almost always have a combustible atmosphere in tanks that have any gas at all remaining in them. Obviously you check the atmosphere with a CGI (combustible gas indicator) before opening up both ends of the tank. Usually that's done by pumping an inert gas into the tank or flushing the tank with compressed air while cutting and of course monitoring all the while.
The heavier fuel tanks very rarely have a combustible atmosphere. They may possibly if they're hot enough inside for the fuel to flash off creating a combustible atmosphere but in my experience that was rare. I'd usually go ahead and flush the tanks just to be sure, but I always liked cutting open fuel oil, jet fuel tanks etc as opposed to gasoline.
I never believed the nonsense about a spark inside the center tank on that 747. Even if somehow an ignition source was generated inside the tank the chances of a combustible atmosphere existing are close to nonexistent.