West Virginia's House is set to vote on legislation that would allow larger pollution discharges into the state's waterways.
The proposal would authorize the Department of Environmental Protection to calculate water pollution limits for cancer-causing chemicals using an average-flow figure — called the "harmonic mean" — rather than the state's current practice of using low-flow water volume to determine allowable discharge amounts.
The change has long been sought by the West Virginia Manufacturers Association, which says it will help redevelopment of vacant industrial properties.
The West Virginia Rivers Coalition says that and another rule revision on "mixing zones" of discharges from multiple industrial sites would remove essential protections from harmful toxins in the state's drinking water.
A similar bill has been introduced in the state Senate.