Terral, I don't care what Christopher Bollyn said, the mans a buffoon. I've used cutting torches and they are the only things which were in that area which could have made those cuts.
Thermite burns downwards and it is VERY VERY messy.
Its also the case that number of firefighters remained at ground zero for months during the clean up so they could search for their fallen comrades.
That photo you show Terral, shows firefighters at the scene AFTER the cleanup had begun, and the dismantling of the remaining structure had begun.
There is no evidence whatsoever that thermite is even capable of making a cut like that. The Truthburn project bottled out of trying to demonstrate that at the burning man festival last year. Cuts like that cannot be done with thermite, they can however be done with oxy acetylene, and thats how those cuts were made.