A federal investigation of the World Trade Center disaster found that a key culprit in the buildings’ collapse was spray-on fireproofing. The planes’ impact dislodged this material from the towers’ steel columns and, unprotected from the searing heat, the columns buckled. Freedom Tower architects promise a better grade of fireproofing, but fire safety expert Glenn Corbett notes, “That’s like saying you’ll use a better grade of Dixie cup.”

Not in the plans: In Europe and Asia, builders use fire-resistant steel. Made with alloys such as molybdenum and chromium, it withstands 100