Firemen evacuated the area as they prepared for the collapse of Building Seven. "We heard a Mayday for everybody to get out of the building [140 West] -- no, I'm sorry, an urgent, three urgents, and we came out of the building [before 4 p.m.]. ... We were then positioned on Vesey Street between North End and the West Side Highway because there was an imminent collapse on 7 World Trade, and it did collapse." [Brian Fitzpatrick, Firefighter (F.D.N.Y.)]
"It's blowin' boy." ... "Keep your eye on that building, it'll be coming down soon." ... "The building is about to blow up, move it back." ... "Here we are walking back. There's a building, about to blow up..."
When buildings such as WTC 7 are demolished the collapse is initiated by an explosion in the central area of the basement. This causes the building to collapse in on itself and minimizes damage to surrounding structures