Row houses were reduced to rubble when an explosion rocked a Philadelphia neighborhood Monday, sending at least eight people to hospitals. Natural gas caused the blast, which collapsed three homes, city officials said in a statement. Witnesses told CNN affiliate KYW that they smelled gas after the blast. "I was sitting in the house and I heard a big bang," Mike McGraw told KYW. "The door slammed and the TV went out." His son, Mike McGraw Jr., said he saw the buckled buildings and watched firefighters hose down a man who had been burned. "They threw this baby out the window because the girl was on fire," he said, "and the fireman had to catch the baby."