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.

However, Karen Bennett, an attorney with Clark Hill who worked on an amicus brief in the case representing seven trade organizations, said the problem with the court's decision was that the science about conductivity was discovered after Fola's permit was issued by West Virginia, a state that doesn't regulate conductivity pollution.

The permit was issued in 2009, and the Environmental Protection Agency issued a study recommending reduced limits for conductivity the following year. The EPA has issued only guidelines on the amount of conductivity, despite environmental groups' calls for a federal limit.

Conductivity pollution caused by mountaintop removal mining can cause salts and other inorganic material to enter the water and raise the salinity levels to points that can kill or severely harm aquatic life, according to the Environmental Monitor.

Bennett said Fola went through the proper permitting process for discharging runoff from the mine and environmental groups didn't fight the permit. After the permit had been approved, the EPA study was released showing stricter restrictions on pollution were needed to prevent conductivity. Environmentalists used the study to file a lawsuit.

Bennett argues that the lower court's decision amounts to an end around proper regulatory processes for changing environmental standards and that courts are making new regulations on their own.

"You have a court imposing a limit that no one knew at the time because it created this limit after the fact," she said.

The case could have wide-ranging implications for multiple industries as it introduces a level of regulatory uncertainty into the permitting process.

Bennett said the 4th Circuit Court of Appeals is a sort of beacon on environmental issues because of the amount of work it does on cases against coal mining companies. If the court upholds the lower court's decision, it in essence will give the OK to other courts to move the goalposts after a permit has been approved, Bennett said.

She said companies with permits that discharge runoff into water legally suddenly would no longer be on firm ground.

"That's a really dangerous precedent for anybody operating with a permit," she said. "It really strips all permittees of the shield that Congress intended under the Clean Water Act.

"Congress intended that once you went to the agency and you were honest about what you would be discharging and the amount that you were discharging, then you should get a permit and you're not going to find yourself in a 'gotcha moment.'"

Environmentalists argue that the court system is needed because state regulators were falling down on the job.

West Virginia regulators refused to accept the science around conductivity levels, said Vivian Stockman, a member of the Ohio Valley Environmental Coalition.

"Over and over we see our state [Department of Environmental Protection] failing to enforce standards and laws that are written to ensure mountaintop removal coal mining corporations don't get away with treating our streams like dumps," she said at the time of the lower court's decision. "Fortunately, we have the Clean Water Act, which allows citizen groups to step up and defend our water. We have no chance to build a better future if we don't have clean water."