Authorities are investigating a fire that destroyed a Cumming business Wednesday afternoon.

According to Capt. Jason Shivers of the Forsyth County Fire Department, Benton Motorsports at 328 Dahlonega St. was engulfed in flames when firefighters arrived.

Shivers said the cause is unknown.

“It’s under investigation already,” Shivers said. “Initially, there’s nothing about it that seems suspicious, but of course we’re going to look into it thoroughly.”

The business owners were inside, he said, when they smelled smoke and evacuated the building.

No one was injured, Shivers said.

“We were able to salvage some part of the front offices,” he said, “but beyond that, it’s going to be a significant loss of the structure and its contents.”

Also, 11 vehicles were lost or damaged in the fire, he said.

Within the first 20 minutes, he said the 30 responding firefighters had the blaze under control.

The stretch of Dahlonega Street was blocked off to traffic in both directions until about 5 p.m. because the water supply line had to be stretched across the street.

Firefighters worked through heat and then thunderstorms, Shivers said.

“Everybody assumes that rain helps fire. It doesn’t,” he said. “Buildings burn from the inside out. … We’re still working on the inside of the building to ensure there’s no fire spread and nothing else that’s going to come back later as a secondary fire.”

The owner of the building, Larry Watson, stood by as he watched the crews put out the flames.

He’s leased the property for 32 years, first to a heating and air company, and more recently to a man who then subleased to Benton Motorsports.

Watson was thankful that no one was injured in the fire.

Barbra Curtiss, who rents a neighboring building for her realty business, said she was driving to her office when the fire started.

“All I saw was flames and black smoke,” Curtiss said. “[I heard] tons of explosions.”