HARRISON TOWNSHIP, Pa. -- At approximately 1:30 a.m. Saturday, a fire at a specialty metal manufacturer provoked a three-alarm response from fire departments.

Crews were on scene for three hours battling the blaze at Allegheny Ludlum.

During the clean-up, an oil-based foam that the firefighters used to extinguish the fire mixed with water that drained through the sewer.

When the contaminated water reached the treatment plant, the liquid's concentration was too thick to be filtered and oil was discharged into the Allegheny River.

Department of Environmental Protection spokesperson, Helen Humphries, said that a private company will be cleaning the river over the next two to three days.