POMPTON LAKES, N.J. (AP) — A New Jersey house where smoke had been reported exploded with volunteer firefighters inside, injuring five of them and sending two to a hospital for treatment of burns, authorities said.

The Pompton Lakes Volunteer Fire Department in Passaic County said on its Facebook page that crews were dispatched at about 2:15 a.m. Saturday after a police sergeant reported smelling smoke coming from the home.

Officials said members of the department entered the home to try to find the source of the smoke and were using a thermal imaging camera when “the home literally exploded, injuring some members manning the hose line at the back of the home and partially trapping others in the basement.”

All were able to get out on their own. Two were sent to St. Barnabus Hospital where they were treated for burns and released, officials said. Three others were treated for minor injuries at the scene. Police also evacuated the lone resident who told authorities he didn’t know how the blaze started.

“I thought we were going to have six fatalities, I really did,” Pompton Lakes Fire Chief Jason Ekkers told NorthJersey.com. “They managed to climb out of the basement with compromised stairs. They all helped each other out, they came out one at a time and we were at the back door, just feeding them out.”

Officials said the blast caused part of the house to collapse and a significant fire resulted. Fire crews from several departments got the flames under control by 3:30 a.m. Saturday. A state fire marshal and Public Service Electric & Gas are investigating.

Olivia Alvarez, 17, told NorthJersey.com that she was looking out the window from her second-floor bedroom across the street when she saw smoke coming from the rear of the home and “thought it was a car or something.” A short time later, she “just saw it all explode,” she said.

“The whole house lifted off the ground, then hit the ground again. The entire house, in one piece,” she said.

Another neighbor, Shirley Jobes, told NJ Advance Media for NJ.com that she heard the blast and looked out the window to see “pieces of the roof on fire up in the air and falling back down.”