UPDATE 10:20 a.m. Philadelphia City Councilman Mark Squilla told reporters this morning it's his understanding that careless smoking led to the blast that leveled one home and led to the collapse of two others in South Philadelphia yesterday.

Squilla told reporters that a contractor was installing a hot-water heater in the recently renovated home when the explosion occurred. The contractor was seriously burned and is listed in critical condition at Temple University Hospital.

Investigators were combing through the wreckage on the 400 block of Daly Street this morning. Preparations are being made to demolish the site, but that won't occur until investigators have the evidence they need from the scene.

Eight people were hurt Monday when a gas explosion caused three row homes in South Philadelphia to fall into pieces, city officials said. One adult suffered severe burns and is in critical condition. 

The other four adults and three children had minor injuries. They are in stable condition.

Rescue crews combed through the rubble for victims Monday. In the early afternoon, they said that the search was complete and no one was unaccounted for.

After the explosion, residents in 70 homes were immediately evacuated. As of 4 p.m., 48 houses were still evacuated.

City officials said the blast happened at 428 Daly St., an unoccupied home that was being remodeled. That building collapsed, along with the properties at 426 and 430 Daly Street.  

The city recently issued four permits for the house where the blast took place. They were for interior alterations, as well as electrical, plumbing and furnace work.

The owner of the building, according to city records, is SCK Investments, L.L.C. Company President Cathy Finney-Hughes did not respond to a request for comment. Executive Secretary Steve Finney told a reporter he had "no comment" and then immediately hung up.

SCK Investments website describes Finney as the former president of the Pennsylvania Association of Realtors and a 10-year member of the board of directors of the National Association of Realtors.

City officials declined to say whether any citizens had recently complained about 428 Daly St. to Philadelphia's 311 non-emergency line. They said a WHYY/NewsWorks.org reporter would need to file a formal Right-to-Know request in order to obtain that information.

Several city agencies are investigating the explosion, and the licenses and inspections department has started to clean up the debris. Philadelphia Mayor Michael Nutter's office said in a statement that "the situation was placed under control" at about 1 p.m.

Fourteen neighbors were taking shelter at John H. Taggart School on Monday afternoon, according to city officials. The American Red Cross is planning to keep the center open through at least dinnertime and potentially longer.

The fire department, the Office of Emergency Management and L&I are expecting to stay on the scene for the rest of Monday. 

Witness reports

Neighbors said they heard an explosion around 11 a.m. They described a frightening and confusing scene.

Ayman Sidarous said his 3-year-old daughter was playing in their backyard at the time. When the blast happened, he grabbed her and ran for his life. Now his daughter is afraid to go back in their home, he said.

Nine-year-old Michael Patrick McGraw, Jr. also lives near the property where the blast happened. He said he saw glass flying "everywhere" afterward.

"I ran into my friend's house to go check on him, seeing if he was OK. He told me his whole house was shaking," McGraw said. "My whole house was shaking. I was thrown off my couch."

Christie Scibblo, a mother of four, said she thought her house was going to fall down during the chaos. She later saw firefighters hosing down a man who had been burned.

Several neighbors, including Daniel Killian, said they could smell gas shortly before the explosion.

"I felt like I was going to throw up," he said.

After the blast, too, South Philadelphia resident Warren Bedoya said it "very gassy outside."

Another neighbor, Joseph Szymborski, jumped into action after the explosion.

"I work night shift, so I was laying down and I literally got thrown off the bed," he said. "So I just ran down the street ... and next thing you knew it, I helped pull three people out of the rubble."  

Szymborski said that one of those people suffered injuries to his skin.

"All peelin' off, burnt off,"  he said, "from his wrist to his shoulder."

Onlookers urged Szymborski to stay back from the rubble. But he didn't take their advice.

"You gotta help people out," he said. "You don't just leave them there." 

Additional reporting by Tom MacDonald, Kim Paynter and the Associated Press.