No residents or firefighters were injured when a four-alarm fire tore into a six-unit townhouse complex in Fort Lee Thursday afternoon, officials said.

The Fort Lee Fire Department received a call reporting smoke at 494 West St. at about 3:07 p.m. Firefighters arrived at the scene to find heavy fire in the back of the first unit, where the fire appears to have started, according to officials.

When firefighters arrived, a propane tank on a barbecue on the rear deck of the unit exploded, said Fort Lee Fire Chief Keith Sabatino.

The first townhouse—comprised of two units—sustained heavy damage in the blaze, and firefighters had to open up the roof of a third unit to make sure the fire didn’t go through.

“Units four, five and six are okay, but nobody can inhabit them because the fire is under investigation,” Sabatino said. “It was a very aggressive, hot fire, and approximately 100 firefighters were used to put out the fire.”

Fire departments from Teaneck, Leonia, Englewood Cliffs, Englewood, Fairview, Palisades Park and Edgewater covered Fort Lee’s other firehouses during the four-alarm blaze, according to Sabatino.

They were staged out of Fort Lee Firehouse No. 3, he said.

County arson investigators were called to the scene after firefighters extinguished the blaze nearly two hours after it broke out, officials said.