Video: Philadelphia buliding collapse traps one, injures 13 A four-storey building being demolished collapsed in one of the largest cities in the US, injuring 13 people and trapping one, the fire commissioner said. Rescue crews in Philadelphia were trying to free the person trapped, city Fire Commissioner Lloyd Ayers said. The injured people were taken to hospitals with minor injuries, he said. The collapse sent debris onto a corner thrift store next door. Rescuers were using buckets and bare hands to move the rubble to search for survivors. "I was standing there looking out my window, watching the men at work on the building, and the next thing I know I heard something go kaboom," Veronica Haynes said. Roofer Patrick Glynn said he had been watching workers take down the building over the past few weeks, and he said he suspected a collapse was inevitable because of the methods the workers were using to tear it down. Carlton Williams of the city's Department of Licenses and Inspections said there were no existing violations on the building, and the demolition company had proper permits for the work.