HARRISBURG, PA (WKBN) – The Pennsylvania Department of Environmental Protection is warning people to not eat fish from the Shenango River in Mercer and Lawrence counties.

The department said “extremely high” levels of polychlorinated biphenyl (PCB) has been found in the water. The levels are over ten times the “no consumption” limit.

PCBs have been shown to cause cancer and negative effects on the immune system, reproductive system, nervous system, endocrine system, and other organs.

The advisory is for all fish in the river and affects the Shenango Lake Dam to the mouth of the river in New Castle.

It’s not known where the PCB is coming from.

The dangerous chemical compound could remain in the river for decades if it isn’t properly cleaned from the water.