At 2:44 a.m. Tuesday, Bay District and Hollywood emergency volunteer responded to a commercial building fire report at Shoppers Food Warehouse in California.
The call came in from the night time manager advising there was smoke in the building.
Arriving firefighters laid out hoses and investigated the source of the reported smoke and odor.
Firefighters remained on the scene until 3:25 a.m., finding nothing, they determined the smoke must have been caused by a malfunction in the ventilation system.