Interesting. I am not a building engineer. I sort of wonder how and where you are suppose to safely store 6,000 gallons of Diesel Fuel in a sky scraper? I would assume this would be emergency fuel for back up generators (or something like that) and the generators might well be powering the elevators (and much more), communications, lights and more in case of power failure. And given that power can go out for several days to a week for many reasons including bombs in the basement (First attack), power outages, snow storms, floods and more. You need some substantial amount of fuel. While basements are the normal spot to put equipment like that, given the first attack and flooding risks, a rooftop might seem like a better choice. This may very well be why the fuel was stored in or near the elevator, just not a good place for it anywhere.