Mercury limits may rise at Oak Creek plant

DNR sets hearing on allowing more toxins

The volume of toxic mercury dumped into Lake Michigan from We Energies’ coal-fired power plants in Oak Creek has climbed over the past decade.

Why?

The company isn’t exactly sure. We Energies is required by state regulators to investigate the source of the increases in its wastewater and find ways to limit contamination that ends up in the lake.

But environmentalists are raising questions about the trend. The Wisconsin Department of Natural Resources is also concerned, although the agency has tentatively agreed to let the state’s largest utility release more mercury in its wastewater than state law currently allows.

A public hearing on We Energies’ five-year wastewater permit will be held at 1 p.m. Monday at the Oak Creek Community Center.

Mercury, a key component in coal, is a human health hazard when released in air and water. Mercury also accumulates in the tissue of fish and because of this, the DNR recommends a limit on consuming fish from Lake Michigan.

Groups like the Sierra Club of Wisconsin and the Clean Power Coalition of Southeast Wisconsin are opposing the agency’s recommendation to give the utility an exception, or variance, allowing the release of about three times more mercury than Wisconsin’s limit to protect fish and wildlife.

The state limit for wildlife is 1.3 parts per trillion. The variance requested by We Energies is a limit not to exceed 4.1 parts per trillion on any one day.

DNR records show monthly maximum figures increased from 1.2 parts per trillion between 2005 and 2008 to about 2 parts per trillion from 2012 to 2018.

“We already know that Lake Michigan has too much mercury in it and we shouldn’t be adding any more,” said Elizabeth Ward of the Sierra Club.

Both the DNR and We Energies are defending the variance.

They say excessive mercury releases aren’t expected to occur frequently, based on records showing levels spike only periodically in water that is piped to the lake.

The variance over the next five years will also require We Energies to investigate the source of mercury contamination and minimize levels from sources such as water that comes into contact with coal ash.

Also, the DNR said there are technical limitations in how much mercu-

ry can be removed by wastewater treatment systems to reach the state’s wildlife limit of 1.3 parts per trillion.

“In this case, there is no treatment that we are aware of that is even capable of reaching 1.3,” said Jason Knutson, wastewater section chief for the DNR. “So this is the best way to get the best environmental outcome.”

Liz Stueck-Mullane is vice president-environmental of WEC Energy Group, the holding company for We Energies.

“This variance will allow us enough time to manage the mercury properly,” she said. “We’re not asking for anything different than anyone else along the lake.”

The DNR has granted exceptions to other major wastewater facilities on Lake Michigan: The Jones Island treatment plant in Milwaukee and plants in Racine and Kenosha because of the technical difficulties in reducing mercury levels in treatment systems. The variances at Jones Island and Racine are higher than for We Energies.

We Energies spokesman Brendan Conway said it’s not clear why mercury levels are rising at Oak Creek. In 2015, the state Public Service Commission approved a request by the company to use more lower-priced coal from Wyoming and less from the eastern United States.

But the company has found lower levels of mercury from western coal than in eastern coal, Conway said.

Ward, of the Sierra Club, emphasized that We Energies was once able to meet the limit, and then things changed. “We don’t know why,” she said.

She said that the environmental groups want the DNR to see a faster implementation of Obama-era regulations governing coal ash disposal that they believe would limit the amount of mercury going through the utility’s wastewater system.

Those regulations are being revised by the Trump administration, and Ward said the Sierra Club sees those revisions as a delay to addressing mercury contamination.