A three-alarm fire at a South Side zinc factory burned for more than two hours early this morning, fought by more than 100 firefighters and a hazardous materials crew.

The fire, at the Imperial Zinc Corporation, was called in at 12:39 a.m. by the factory's only on-duty employee, who reported a fire at the rear of the building, located at 1301 E. 103rd St. 

The employee reported seeing "a light haze and a flash," according to fire department spokesman Larry Langford.

The hazardous material team was called out because of corrosives materials and gas inside the factory, Langford said.

No one was injured in the blaze, which left the one-story, 1,600 square-foot warehouse with extensive damage and a  partially-collapsed roof. The fire was extinguished at 2:33 a.m.