Allentown, PA – A possible gas explosion left several rowhomes in Allentown engulfed in flames overnight. At least 10 homes caught on fire, officials say.

It happened on the 700 block of North Fountain Street, around 3:15 a.m. Sunday. UGI Utilities says it appears there was an explosion that led to a three-alarm fire. However, it remains unclear what sparked the explosion.

The incident caused at least one home to collapse, Allentown Fire Deputy Chief Efrain Agosto said during a press conference Sunday morning.

“When the guys got here, they found one structure pretty much completely collapsed with fire in place,” Agosto said. “From my understanding, there was nobody [inside the home that collapsed]. It was supposed to be a vacant structure. There was nobody living in that home at that time.”

“The fire afterward basically has taken up pretty much the whole block. From the sound of it about 10 homes,” Agosto said.

Neighbors reported hearing a loud explosion but it remains unclear if it was because of gas. Agosto said arriving crews did not detect any odor of natural gas.

“My daughter woke me up saying, ‘run.’ I didn’t hear anything,” resident Cindy Hewco said. “They thought it was a car accident here. I guess the house fell outside somewhere so I ran. They’re in the car right now with my dogs. I got fish in here, a hamster, a lizard which is still in the house, my purse, all our phones are still in the house. We can’t even go in there to get them. I have nothing.”

Video from a resident shows the moments after the reported explosion as residents frantically ran out of their homes and attempted to wake up neighbors. Residents can be heard yelling, “Get out! There is a fire!”

“It’s very traumatic. I was sitting there, working on some videos, right in the kitchen and I heard something that sounded like a dump truck or a garbage truck but it was all night. And I heard something like it fell out of the truck, like rubble,” McKenzie said. “So, I look out the front door and a bunch of rubble on the floor and then I see the flames come out. So, something made the whole front of the house literally collapse down and the rubble was littering the street. It’s still in the street. And now the fire is consuming the whole block. From the top down. These are older homes, they don’t have the fire insulation. So it’s very traumatic.”

At least one person was unaccounted for during the early morning hours. That person has since been located safely, Allentown police said.

One firefighter was taken to the hospital to be evaluated for a shoulder injury. That firefighter has since been released. There were no other reported injuries.

The American Red Cross says a dozen families — 44 total people — have been displaced. Eight of those families were displaced by the fire and four others have been temporarily displaced by demolition at the site.

Authorities are asking people to remain clear of the area of 9th and 10th Streets and Tilghman to Washington Streets as they continue to investigate and battle flames. As of 8 a.m., at least five homes were still burning.

As of 11 a.m., officials said crews were putting out hot spots but there was no longer an active fire.

The cause of the blaze is under investigation.