A fire inside a hopper at a large commercial warehouse prompted a brief evacuation Friday afternoon as Turlock firefighters fought to keep the fire from spreading to other areas of the structure.

The Turlock Fire Department was dispatched to the 100 block of South Walnut Road around 1 p.m. Friday to respond to a commercial fire alarm.

The first crews to arrive from Squad 32 and Truck 31 were told by employees there was a smoldering fire in an industrial bag-house filter.

A significant portion of the warehouse was filling with smoke when the firefighters entered the structure. Crews worked quickly to close several large interior roll-up doors, which prevented the smoke from spreading to other parts of the warehouse.

Crews worked in concert with on-site staff to effectively ventilate smoke from the warehouse, gain access to the hopper and ducting, deploy hoses and fully extinguish the fire. Automatic fire sprinklers inside the hopper helped to contain the fire, however, it continued to smolder in many locations and spread to the adjacent ducting.

Additional resources from neighboring agencies were requested to assist through resource sharing and mutual aid agreements.

Turlock Rural Fire District provided city coverage during the incident while AMR provided an ambulance to standby on scene.

Crews remained on-scene for approximately four hours. The cause of the fire remains under investigation.