Are you sure that it is pressure, and not the fuel wrecked the seal?

Like said above you could be in for a law problem.

With that said this is what I started to do.  The standard fuel tanks, little square boxes at farm stores, never held up.  Cracked and leaked all over.  We sell propane and have old tanks around.  So now I have 3 250 gal propane tanks for hauling fuel.  2 are on decks of semis,  one uses 12 volts and one I have rigged up with air pressure through the trailer air tank. Going to make the other one air pressure this winter.  One is in back of a pickup that I pull behind the strip tiller to the field.  Also have a 1000 gal anhydrous tank on running gear for a remote fill for our semis hauling chicken litter.  All are not "legal"  but have never been bothered around here.