Just to second Gravy, we used tnakers in the military on Hemmitt trucks. The fuelers have a tank close to the size of an 18-wheeler tanker, and they're 10,000 gallon tanks.
I could see maybe 15,000 for an 18 wheeler, if that.
Also, does Sentinal understand that there is a difference between burning and explosion? A tanker truck that cracks open (from wreck or turn-over or whatever) and ignites is not under pressure, and is not sprayed out everywhere due to impact force. It will typically burn, rather than explode, and the fireball isn't nearly as large.
The jet fuel from the plane was free of containers (as the fuel tanks would have disintigrated on impact at that speed) and sprayed across and over everything. It was at least partially aerosoled, plus spread over a wider area. Heck, you can test this at home (but only do so at your own risk):
Take 2 gallons of gasoline. Put one gallon in a metal bucket. Spread the other gallon out over the ground/driveway/whatever. Ignite each, and time how long it takes them to burn away. I'll garauntee you the spread out fuel will burn off much quicker.