(RNN) - Six people died when a building collapsed in Philadelphia, trapping several people.
Rescue teams freed 14 people from beneath a building that crumbled while workers were demolishing it. One of the people rescued was a woman who was trapped for several hours before walking away under her own power with no major injuries, according to the city's mayor.
At least three people, including two women, were taken to Hahnemann University Hospital. Five people were taken to Thomas Jefferson University Hospital, and five were taken to the Hospital of the University of Pennsylvania - one male and four females. Several of those people have since been released.
Fire Commissioner Lloyd Ayers said the rescued all were in stable condition with minor injuries.
Late Wednesday, a 61-year-old woman was pulled from the rubble alive. She is listed in critical condition.
Police said she was the last of the victims for which they were looking, but they emphasized early Thursday morning that the scene remains an active search-and-rescue site.
The four-story building was located in Center City at the heart of Philadelphia. It fell onto a Salvation Army store inside a two-story building located next door. Officials said a large number of people frequently shopped there.
Ayers said 125 rescue workers, 35 pieces of equipment and two search dogs were part of the rescue effort, and most of the people taken to hospitals had minor injuries. He expected the operation to continue until at least early Thursday and possibly longer.
The building located on the corner of 22nd and Market streets came down about 10:45 a.m. EST. A fire station was located a block away, allowing for a quick response time.
Center City is the busiest area in Philadelphia, home to City Hall, historic structures, hundreds of restaurants and a thriving business district.
The Philadelphia Police Department said it appeared to be "an industrial accident" in a tweet it sent out soon after the accident.
Sara Frey, who works in a building on the opposite corner of the collapse site, said it landed on the thrift shop while people were still inside.
"There used to be a XXX theater there, and they were taking it down," Frey said. "I'm still getting goose bumps. Thank God it wasn't lunchtime because this is a busy commercial area, and we've walked by there so many times. This is unreal. I drive by there every morning. There are people there on the corner every morning."
Frey said construction had been going on for a while, and workers were "taking the building apart piece by piece." She did not hear an explosion before the collapse.
Police closed off streets and cleared the area to allow access for rescue workers.
More than 279,000 people work in Center City - about 44 percent of Philadelphia's total job force - according to Center City District & Central Philadelphia Development Corporation. More than 305,000 people travel through the downtown area each day.
Center City also holds a large residential population of more than 57,000 people reported in the 2010 census.
The Salvation Army made plans to send its own disaster response team to provide support for survivors and first responders.
"At this time, we are gathering information about the details of the building collapse at 22nd and Market Street in Philadelphia today," said Maj. John Cranford of the The Salvation Army of Philadelphia. "Our no. 1 concern is for the safety of our customers and the employees who were involved. We are coordinating with the police and fire department and local authorities."
The Occupational Safety and Health Administration (OSHA) is at the scene investigating the collapse and the building's history.
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