A pumping problem at the Cranberry sewage treatment plant in Butler County on Sunday caused the release of untreated sewage into Brush Creek over a 12-hour period and killed an undetermined number of fish.

The problem was discovered yesterday morning by workers at the Brush Creek Pollution Control Facility. They reported the problem to the state Department of Environmental Protection and communities downstream on Brush Creek, which flows into Connoquenessing Creek, a tributary of the Beaver River, and then the Ohio River.

No communities draw drinking water from Brush Creek, but it is a fishing stream that contains smallmouth bass and other game fish.

Duane McKee, Cranberry director of public works, said the plant lost power about 2 p.m. Sunday, which caused pumps to malfunction and sewage to back up into the creek. He said the equipment was working properly yesterday. The plant handles about 3 million gallons a day.

The state DEP and the Fish and Boat Commission are investigating. Residents living along Brush Creek were advised not to fish, wade, swim or drink from the creek until state officials determine the extent of the discharge and damage.