Bechtel engineers, responsible for safety at Ground Zero, wrote in theJournal of the American Society of Safety Engineers: “The debris pile at Ground Zero was always tremendously hot. Thermal measurements taken by helicopter each day showed underground temperatures ranging from 400ºF to more than
2,800ºF.”
https://tobefree.wordpress.com/2014/01/07/ae-for-911-truth-high-temperatures-persistent-heat-molten-steel-at-wtc-site-contradict-official-story/