A demolition expert wondered what precautions were taken to protect the Salvation Army store, especially since it remained open. Stephen Estrin, a Florida contractor who has testified as an expert at several trials involving building collapses, also questioned whether the demolition was being done by hand or with machinery. A piece of equipment with a claw device was seen amid the debris Wednesday.
"This is an inner-city demolition of a masonry building, which would normally be done manually because of the inherent risk—predictable if certain things are not done very slowly and very carefully—of a collapse," Estrin said. "One of the problems with claw work is it sets up a vibration in the walls."
Witnesses said they heard a loud rumbling sound immediately before the collapse. More than 100 rescuers and several police dogs searched through the rubble.
"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," said Veronica Haynes, who was on the fifth floor of an apartment building across the street. "Then you saw the whole side of the wall fall down . . . onto the other building."
Bernie DiTomo was driving past the Salvation Army store in his pickup truck, on his way to an appointment, when the collapse happened.
"The next thing you know, I heard a rumble, and a building and a sign fell on my truck," he said.
He said he lay down in the seat of his cab. It was probably over in about 30 seconds, he said. There was a lot of dirt and dust, but he was able to open the door and get out, unhurt. His truck remained nearby, partially covered in debris, as he watched recovery efforts from across the street.
High school student Jordan McLaughlin said a thick cloud of dust immediately enveloped the area.
"It was hard to breathe," he said.
The accident happened on the western edge of downtown, between the city's business district and its main train terminal, 30th Street Station. The block had long been a seedy link between gleaming skyscrapers and the busy area around the station.
Maj. John Cranford, of The Salvation Army in Philadelphia, said officials were coordinating with the police and fire department and sent their own disaster response team to the site to serve survivors and first responders.
"Our No. 1 concern is for the safety of our customers and the employees who were involved," he said. "We ask for the public to pray for those involved."
Records show the collapsed building was sold in 1994 for $385,894. Marinakos, the architect, said plans tentatively called for the block to be redeveloped into retail stores and apartments.