IRVINGTON, N.J. (CBSNewYork) – A three-alarm fire destroyed a home and damaged seven others early Wednesday morning in New Jersey.

Investigators still don’t know what started it.

The flames were so intense they melted parts of a fire engine at the scene.

The fire broke out around 2 a.m. on Franklin Terrace in Irvington.

“It was huge. It was a huge fire,” said neighbor Amanda Flash.

Fire officials believe the blaze started in an unoccupied house that appeared to be under construction.

When firefighters arrived, two homes were already engulfed.

“The most difficult part is it was a stubborn fire and, obviously, it had a jump on us in terms of reflex time, because it’s not common when you arrive on a fire to see it so fully involved,” Irvington Fire Chief Antonio Gary told CBS2’s Jenna DeAngelis.

The heat melted the siding on several other houses, and multiple cars were charred.

“One of the police officers told me to get everybody out the house, because the flames were so much they were melting the siding on the houses,” neighbor Christine Williams said.

Amanda Flash was at work, but her husband and three young children were sleeping inside their house next door.

“He kind of heard a noise and it was really, really hot. So what happened – he got up, he saw a fire, he grabbed our kids and ran out the house,” she said.

That saved their lives.

Several fire departments helped Irvington battle the blaze, and the Red Cross assisted two families that were displaced. One firefighter suffered a minor injury and was treated at the scene.

“The heat – it was like you were right there inside a flame. Like you were standing right outside of it. It was crazy, really crazy,” said Williams.

“It’s not a good feeling, because you never expect something like this to happen. I know the people in the house, the houses and stuff,” said Williams. “To see them not have anything, it’s just unreal. It really is.”

“Material things can easily be replaced, but my children, my husband, they can’t be replaced,” Flash added.

The arson squad was called to investigate the cause of the fire.