A fire of unknown origin enveloped the old gun firing range building at 5840 Bankhead Highway in Douglasville Friday, closing down the busy U.S. Highway 78 as crews battled the raging blaze amid upper 90-degree weather.

“The range has been out of business for some time and I understand the building was under renovation,” said Wes Tallon, county communications and community relations director.

Tallon said the first alarm came in at 4:15 p.m., with first responders reaching the scene by 4:18 p.m. He said 12 engines answered the alarm.

He said no injuries were reported, but fire crews were swapped out every 10 minutes to protect against heat exhaustion.