Eleven construction workers were injured and three firefighters sent to the scene were slightly hurt in the collapse, which left a pile of steel, stone and wood that reached up to the third-floor window of the building at 215 Park Avenue South, they said.
The officials said in early reports 30 people had been injured, but later reduced that number.
In a scene eerily reminiscent of the search for victims of the Sept. 11 World Trade Center attack, police and fire workers sifted through the rubble looking for those trapped underneath, while search dog teams walked over the pile as the animals tried to pick up the scent of any victims beneath.
About 250 police and firefighters, some of whom worked in rescue operations at the World Trade Center, were dispatched to the scene. They were working in bucket brigades passing rubble and handing steel rods from hand to hand as they tried to clear the pile of debris.
"The amount of weight that was on the floors of the scaffolding was very heavy," New York Fire Commissioner Thomas Von Essen said.
The building's lessee, S.L. Green Leasing L.L.C. said in a statement the workers were repairing and restoring the facade of the 20-story building located near Union Square.