Police, fire and PSE&G officials rushed to the scene on Abbott Avenue in Ridgefield shortly before 11:30 a.m.
Witnesses described a noise that sounded similar to a plane crash, and many of them grabbed their kids and ran for safety before they knew what was happening.
A neighbor from three doors down said the force of the blast knocked him off his feet.
"I was in my backyard doing gardening work, and I looked over my fence, and I saw completely there was no house," he said. "It was leveled to the ground. I couldn't believe my eyes."
Video from NewsCopter7 showed a decimated scene.
WATCH: NewsCopter 7 over the blast site in Ridgefield
The explosion littered the street, sidewalk and nearby cars with debris. Neighboring homes suffered minor damage and were evacuated.
An off-duty police officer who lives a block away ran to the scene. He and another officer heard a sound in the burning rubble.
They found a survivor under a pile of wood and pulled the victim from the rear of the home, which was already collapsed.
"There was debris everywhere, and when we got to the back of the house, all of the officers were able to lift this plank of wood up where we were able to see him underneath," Ridgefield police Officer Hagop Cigercioglu said. "As I called to him, he did respond. He gave his name, and I advised him of the house that was on fire, that he needed to crawl out. And we were able to take some wood out to make a big enough hole where he crawled out. And several officers and I helped him get out of the house."
The victim has not been identified, but he is believed to have been the only person inside. He was rushed to Hackensack University Medical Center in stable condition.
BREAKING: House explosion in Ridgefield, NJ. House is leveled. Knocked 1 neighbor off his feet as he was watering garden. Another says he was lifted off his bed. Neighbors say sounded like plane crashed. Off-duty cop who lives nearby pulled resident from the rubble. 1/2 pic.twitter.com/ua0qDBuLZ3— CeFaan Kim (@CeFaanKim) June 17, 2019
"The off-duty officer and responding officers were able to pull the lone resident from the rear of the structure, while assisting officers were able to suppress around the surrounding fire," Ridgefield Police Chief Thomas Gallagher said.
While working to fight the flames that followed the explosion, firefighters faced an additional challenge.
"We had to hold off fire suppression operations due to a gas leak," Ridgefield Deputy Fire Chief David Brierty said. "Once the gas leak was taken care of by PSE&G we were able to extinguish the fire."
It was not immediately clear if the leaking gas caused the explosion. Meantime, neighbors were forced to deal with the aftermath.
"The houses that are surrounding the explosion site are all off with gas," Bergen County Executive Jim Tedesco said. "The electric...because of all the fire hoses, we can't get the trucks in. So they're going to take the electric out for a while."
Still, the level of devastation left many simply thankful the injuries were not more severe.
"This is a sad situation," Ridgefield Mayor Anthony Suarez asid. "Fortunately for the borough, it could've been a heck of a lot lot worse."
Authorities say one firefighter and two police officers suffered minor injuries fighting the blaze. The cause is under investigation.
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