Joe Casaliggi, NYC firefighter: "You have two 110-story office buildings. You don't find a desk, you don't find a chair, you don't find a telephone, a computer. The biggest piece of a telephone I found was half of the keypad, and it was about this big. The building collapsed to dust."
This is very clearly a case of controlled demolition. When a building collapses due to structural failure, like when a building collapses because of an earthquake, it doesn't just disappear to dust.