Eric McClellan said he ran to the scene of the explosion and saw homes flat or nearly so.
"Somebody was trapped inside one of the houses, and the firefighters were trying to get to him. I don't know if he survived," he said, adding that firefighters ordered him to leave the area.
Once the flames were out, firefighters went through the rubble and damaged homes one at a time in case people had been left behind, Fire Lt. Bonnie Hensley said. They used search lights until dawn as they peered into the ruined buildings.
Along with the two people killed, seven people were taken to a hospital with injuries, Bacon said. Everyone else was accounted for, he said.
Four of the seven who were injured minor injuries, fire officials said. They did not provide details on the others or identify those killed.
An investigation was underway, said Bacon, who would not rule a gas leak in or out.
Dan Considine, a spokesman for Citizens Energy, said people usually smell gas when there is a leak, but the utility had not received any calls from people smelling gas in that area.
Dan Able, a 58-year-old state employee who lives across the street from the two homes that exploded, said his first thought was that a plane had hit his house.
The blast was "a sound I've never heard before, it was so loud," he said. His windows blew out and a bedroom ceiling collapsed on his wife, Jan. He pulled her out, and they went outside.
"Both houses across the street were on fire, basically, just rubble on fire," he said.
The Ables and about 200 other people evacuated from the neighborhood were taken to a nearby school. Some who had been sleeping arrived in their pajamas with pets they scooped up as they fled. Most eventually left to stay with relatives, friends or at hotels, but seven or eight remained through the night, sleeping on cots.