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The cause of the blast was unclear. Two neighboring homes were severely damaged and were condemned. One of those homes housed a daycare.
Fire Chief Robert Scheirer says two men were conscious when they were taken from the leveled home and to a hospital.
The men are identified as Cesar Coto, 52, and Miguel Irizarry, 41. The extent of their injuries was not clear. The two men were the only people injured in this blast.
Scheirer says he felt the blast in his office about a mile away and thought something in his building had blown up. He says it's amazing that anyone survived.
Other people a mile away also said they heard the blast. CLICK HERE to see David Henry's report.
A total of 19 people (12 adults and 7 children) have been displaced from their homes in the area of the blast. They are being helped by the Red Cross.
Investigators, including those from the Bureau of Alcohol, Tobacco and Firearms will begin sifting through the debris on Wednesday. They will be looking for any clues, including the possibility that explosives may have been in the home.
A neighbor, Bob Walko, said the brothers' elderly mother lived in the house and used a wheelchair but was not usually home in the afternoon.
Walko, 55, said he thought the explosion was a plane crash. It shook his house and knocked pictures and clocks off the walls, he said.
"It was just unbelievable. I never experienced anything like that in my life," Walko said.
Walko said he ran across the street and found one brother under a couple of boards. He removed the lumber and said the man complained of back pain. The other brother was found in the basement.
Firefighters and gas utility workers were investigating. Chris Brown, a spokesman for gas company UGI Utilities Inc., said workers could not find any elevated gas readings after the blast.
"Whether there was a leak as a result of the explosion or whether a leak caused the explosion, we have no idea at this point," Brown said.
No word on what touched off the explosion.
The Associated Press contributed to this report.