But the towers had not been built using seventeen-foot lengths of steel; the actual pieces in the floors were at least twice that length. When a thirty-five-foot length of steel, the true size used in constructing the floors, was tested in 2004, the federal investigators found that the fireproofing could not provide two hours of protection. Long before September 11, the floors in two of the world’s landmark skyscrapers had been more vulnerable to fire than was thought.
