SPRUCE PINE, N.C. -- Residents of the Spruce Pine area are being allowed to return home after a fire Saturday night at a quartz processing plant prompted evacuations.

The fire broke out just before 11 p.m. Saturday at the Unimin Corporation Quartz-Feldspar plant on Highway 226 between Spruce Pine and Ledger.

The Mitchell News Journal reported that the fire was contained by 5 a.m., but Mitchell County Emergency Management Director Eric Wiseman said the cause has still not been determined.

Emergency crews issued a mandatory evacuation for a 4-mile radius around the plant due to a potential of wind blowing hazardous chemicals into the area, and Highway 226 was closed between Spruce Pine and Bakersville from 11 p.m. to 9 a.m.

Shelters were set up at a nearby church and middle school. FOX Carolina has learned the plant was vacant at the time of the fire.

Fire departments from surrounding counties, including Mitchell, Yancey, Madison, Avery, Buncombe, McDowell, Burke and Rutherford assisted in putting out the blaze.

The Mitchell News Journal also reported that the Federal Bureau of Investigation is coming to assist in the investigation.