Semi tankers typically hold 8,000-9,000 gals, not 12 million each. Something’s wrong with someone’s math.
http://en.wikipedia.org/wiki/Tank_truck
Looks like bad wording. Liberal media is kinda short on proofreaders these days. Maybe they meant that the “hundreds” (i.e. convoys) of trucks would be delivering 12 million gallons per hundreds? Not sure.