A massive three-alarm fire destroyed a fiberglass manufacturing warehouse in far north Fort Worth on Thursday afternoon, reducing a building firefighters described as longer than a football field to rubble.

The fire broke out around 2:45 p.m. at F&F Composite in the 5800 block of Egg Farm Road, just off North Main Street.

Witnesses at the scene said employees inside the manufacturing facility heard a “pop” just before the fire started and quickly evacuated as flames spread through the building.

F&F Composite employee Vincent Ridenhour was not inside the warehouse when the fire began. After learning about the fire, he rushed to the facility and watched as firefighters battled the flames.

“I heard it started in the ceiling and by the time they noticed it, it was already too late,” Ridenhour said. “I’m glad everyone is safe. No one got hurt.”

When firefighters arrived, they initially believed people might still be trapped inside the warehouse. Those concerns were later resolved after crews confirmed everyone had safely evacuated.

The warehouse manufactures fiberglass landscaping materials and similar products. Firefighters said chemicals stored inside the building added another layer of complexity to the response.

Craig Trojacek, a spokesperson for the Fort Worth Fire Department, said the warehouse stretched “as long as or longer than a football field.”

“When you’re on the nozzle, you’re thinking about nothing but putting that fire out and making sure you can find somebody to get them out to safety,” Trojacek said.

As the fire intensified, the roof began collapsing toward the center of the structure, forcing firefighters to pull crews back and change tactics.

The extreme North Texas heat also made conditions more difficult for firefighters.

“When you’re in this gear and fighting fire, that’s very taxing on the body,” Trojacek said. “Mother Nature’s always gonna win, is what I say.”

Fire crews rotated in and out throughout the afternoon as they battled both the flames and the heat. No injuries were reported.

The cause of the fire remains under investigation.