PSE&G utility got a call shortly before noon that a contractor had damaged a gas line, spokeswoman Lindsey Puliti said. Utility crews were repairing it about an hour later when the gas line ignited, injuring five PSE&G workers and two people who worked for the contractor, according to Ewing police Lt. Ron Lunetta.
The force from the explosion buckled windows in an apartment complex nearby, said resident Marsha Brown, and pictures fell from her walls.
"It felt like a bomb," she said.
She ran to the town house complex, saw a home engulfed in flames and two utility workers on the lawn with injuries that apparently included broken bones. She said she saw another worker on a sidewalk crying, being held by a woman.
At least one home was a blackened pile of rubble, and others had damage, including windows that were blown out. Debris was widely scattered, with insulation hanging in some tree branches.
"My body was shaking. I like to say I am calm, but I was shaking," said Brown, who had a day off from her job as an infant hearing screener at a hospital. "You could feel the flames, everything."
A resident of the complex, Bryan Gentry, drove home minutes after he heard an explosion and as he got closer, saw a black smoke cloud. The fire was intensely hot, he said, and he saw one person walking away from the fire who appeared to be stunned.
"It was just unreal," he said, adding that emergency crews responded "really fast."
D'Amelio said the injuries included concussions, broken bones and minor shrapnel wounds. Given the destruction, D'Amelio said he was "very pleasantly surprised" that the injuries weren't worse.
Normally during that time of day, the people in the neighborhood are at work and their kids are at school, Gentry said.
Mulvihill reported from Trenton. Associated Press writer Kevin Begos in Pittsburgh also contributed to this report.