INDIANAPOLIS – Crews responded Saturday morning to the south side after callers reported seeing heavy smoke and fire coming from an industrial building.

According to the Indianapolis Fire Department, firefighters were dispatched around 8:10 a.m. to Indianapolis Industrial Center Recycling Plant Building No. 3 at 3000 Shelby St.

The business decommissions products and recycles them, IFD said. The building owner said the business has been at the location since the 1920s.

No one was inside the building when the fire broke out. The building is about 15,000 square feet. Dispatchers received multiple calls of heavy smoke and fire coming from the building.

IFD said 28 units were dispatched, with a second alarm called just before 9 a.m. About 75 firefighters were called to the scene; IFD had the fire under control at 9:42 a.m. Crews remained on the scene for about two more hours.

Investigators believe a fifth wheel parked inside the building caught fire, although the exact cause of the fire is unknown. It could be electrical in nature, IFD said.

No one was hurt. The Indianapolis Metropolitan Police Department, Indiana Emergency Medical Services and IFD Fire Buffs were also called to scene. The Marion County Public Health Department has been requested to assess any runoff and additional health concerns.

The fire remains under investigation.