Ohio River regulators have voted unanimously to allow a West Virginia company five more years to comply with new, more stringent pollution requirements.

Right now, companies that discharge into the Ohio River are allowed a mixing zone, where the pollution mixes with the river and gets diluted; monitoring is done downstream to make sure the company is in compliance. But next October, no mixing zones are allowed. The pollution coming straight out of a company’s pipe has to meet new, stricter standards for mercury, set by the Ohio River Valley Water Sanitation Commission, or ORSANCO.

But PPG Industries, a chlor-alkali plant in Natrium, West Virginia, will have five more years of using a mixing zone. The variance allows the company to discharge a monthly average of 55 nanograms of mercury per liter of water. The number is far above the new standard (12 nanograms of mercury per liter), but reduced from the company’s historic numbers (which used to top 200 nanograms of mercury per liter, but more recently have been around 70).

Thomas Easterly is an ORSANCO Commissioner and the head of Indiana’s Department of Environmental Management. He says not granting the variance for PPG would have shut the plant down, and still not improved water quality. That’s because the grounds of the plant are contaminated, and a lot of the mercury pollution is coming in groundwater runoff.

Well that’s something that we would normally worry about but in this case, it wouldn’t matter if the plant operated because the pollution’s from the ground, so we need to deal with that,” he said.

Easterly also noted that even if the plant shut down, it wouldn’t be able to meet the new, strict 12 nanograms of mercury per liter standard.

Environmental groups fought the variance, arguing that there’s already a problem with high levels of mercury in the Ohio River. Mercury bioaccumulates in fish and eating fish with high levels of mercury can be harmful to children and women in childbearing years.

As one of the conditions of the variance, ORSANCO is requiring annual fish tissue samples. The mercury standard for fish is .3 milligrams per kilogram of tissue, and if the fish downstream don’t meet that benchmark, ORSANCO commissioners can reconsider the variance.

Erica Peterson reports on energy and the environment for WFPL. She is also Enterprise Editor.