Deputy Fire Marshal Amiel Thurston said small, smoldering fires inside the building are still potentially dangerous.
Eight engines and two trucks responded to the fire, which started just after 4 p.m. at the facility at Fremont and South Grimmer boulevards, Thurston said.
He said as a precaution, the firefighters are asking people near the smoky area to stay indoors.
No injuries were reported and the cause is under investigation.
