That's true, but the tanks would be pressurized to some extent, otherwise the more volatile compounds in the fuel would boil off into the atmosphere, leaving behind a more 'sludgy' fuel mixture.
Think of the gasoline you keep on hand for your lawn mower. It's in a closed container, and after a few minutes, or hours depending on the temperatures, it has a pressure built up.
That said, I've believed it was a missle from the very beginning. I just never knew about the Gorelic involvment in the cover-up. Those people were hip deep in things during the whole eigth years.
The tanks aren't pressurized when they are empty. Nor when they are full.