Proponents list several things. The towers came down fast and nearly straight; WTC 7 fell into its own footprint with a period of free fall. Witnesses, including firefighters in the oral histories the city released in 2005, described what sounded like explosions. Firefighter Richard Banaciski, waiting at a command post on West Street, told an FDNY interviewer in December 2001 that after 10 or 15 minutes “there was just an explosion. It seemed like on television they blow up these buildings. It seemed like it was going all the way around like a belt, all these explosions.” [1][4] Video shows puffs of dust bursting from floors below the collapse front. [2][3]
They also argue that no steel high-rise had ever collapsed from fire, and that NIST stopped its tower models at collapse initiation. [2]
Approved reader comments and ratings are shown on the interactive edition. This plain reading edition does not load them.