Firefighters say pieces of cardboard caught fire near the back of the Grocery Outlet on Blackstone and Effie. The flames then spread to inside the store.
A sprinkler-system inside the store kept the fire from growing. Fire crews were able to put the flames out quickly.
Damage to the store was minimal; the fire mostly burned cardboard in a storage section.
Firefighters are working to repair some of the water damage left behind by the sprinklers.
The cause of the fire is under investigation.