Roughly 75 firefighters battle structure fire in Glendora

About 75 firefighters battled a structure fire that emitted thick plumes of smoke and heavy flames at a vacant building in Glendora.

The blaze was reported shortly before 9 p.m. at 1332 S. Lone Hill Ave. There, firefighters were met with a large fire on the roof of an empty structure. Due to the severity of the fire, the building's roof partially collapsed, forcing crews to respond from the outside.

Fred Fielding of the Los Angeles County Fire Department said crews do not believe the structure was under commercial use at this time. It does not appear anyone was inside the building at the time of the fire.

The cause of the blaze remains under investigation. No injuries were reported in connection with the fire.