A federal appeals court is set to hear oral arguments Thursday in a case that could determine if companies discharging runoff from industrial activities can have their state permits changed by federal courts.

The case, Ohio Valley Environmental Coalition v. Fola Coal, deals with a lawsuit by an environmental group that said mine runoff from a Fola Coal operation was making a nearby stream toxic to aquatic wildlife because it was increasing the electrical conductivity of the water. A lower court agreed in January 2015 that Fola violated its runoff permit issued by West Virginia. The case is set to be heard by the 4th Circuit Court of Appeals in Richmond, Va.