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Ameren Missouri implementing EPA-approved treatment techniques at its Huster Substation
Cleanup efforts will continue until groundwater beneath the substation achieves the strict standards established by the EPA

St. Louis (Feb. 9, 2023) – Ameren Missouri has started implementing U.S. Environmental Protection Agency (EPA)-approved measures to contain and remove remnants of cleaning solvents used decades ago at a substation in the City of St. Charles. Treatment techniques targeting chemicals directly underneath the substation site are now underway, with completion set for the end of March, followed by a monitoring period. All work is being performed under the supervision of the EPA. Based on prior experience, a reduction in concentration levels is expected by early summer.

"Ameren Missouri remains committed to the safety of St. Charles residents. The drinking water in St. Charles remains safe. We are also committed to working cooperatively with the EPA to address groundwater impacts at and near the Huster substation," said Craig Giesmann, director of environmental services at Ameren Missouri.

Ameren Missouri's plan is informed by independent experts, including Dr. Ray Ferrara, a nationally recognized authority on water issues with more than 40 years of experience.

"Very similar methods have worked in locations across the country," Ferrara said. "It is also a timely and practical step to take."

"The EPA has repeatedly stated that our comprehensive plan is appropriate to protect the local water supply," Giesmann said.

This work is part of Ameren Missouri's ongoing cleanup efforts to successfully identify and implement technologies to reduce Huster substation on-site and potential off-site impacts.

In addition to injecting materials to destroy residual solvents, Ameren Missouri is installing subsurface barriers at strategic locations for added protection. The barriers create a chemical reaction that captures remaining suspended residuals in the groundwater before it passes out of the substation property. In addition, utilizing a series of extraction wells, an above-ground groundwater capture system permitted by the Missouri Department of Natural Resources also contains and treats on-site groundwater. Cleanup efforts will continue until groundwater beneath the substation achieves the strict standards established by the EPA. The barrier installation and treatment applications are expected to begin to work immediately and to be completed by the end of March. Monitoring will measure effectiveness.

Ameren Missouri continues to cooperate with the EPA on these additional treatment steps. These treatment techniques may also be utilized at other offsite locations.

Ameren Missouri has been providing electric and gas service for more than 100 years, and the company's electric rates are about 25% below the Midwest and national averages. Ameren Missouri's mission is to power the quality of life for its 1.2 million electric and 135,000 natural gas customers in central and eastern Missouri. The company's service area covers 64 counties and more than 500 communities, including the greater St. Louis area. For more information, visit Ameren.com/Missouri or follow us on Twitter at @AmerenMissouri or Facebook.com/AmerenMissouri.