PSE&G issued a release on the explosion saying a contractor was working on a line when it became damaged and then ignited, KYW-TV, Philadelphia, reported.
Nearby structures were reported on fire and residents were evacuated, emergency crews said.
Debris was scattered throughout the area and landed in trees and roofs of nearby homes, police said.
Witnesses said the explosion was loud and blew off doors and windows of nearby homes.
"I was getting off my couch. ... I got up, and there's was just this very loud explosion," a man identified as Matt told KYW. "Right after that, my front door -- glass door -- got shattered. And I kinda flew back ... from the explosion."
The utility dispatched crews to the scene to shut off the gas and electricity.
PSE&G said two of those injured were utility employees and that their injuries were non-life-threatening.