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Managing CCRs

This ash basin at the Meramec Energy Center closed in the spring of 2018.
This ash basin at the Meramec Energy Center closed in the spring of 2018.

The Coal Combustion Residual (CCR) Rule contains technical standards for the design, operation and closure of landfills and basins located at coal-fired energy centers. Through this rule, EPA regulates CCR as solid waste under the Resource Conservation and Recovery Act (RCRA). RCRA requires that CCR facilities operate in a manner that presents "no reasonable probability of adverse effect on health or the environment." In 2016, Congress passed legislation that authorized states to develop CCR programs and adopt, as appropriate, site specific criteria. In 2018 and in recognition of this congressional action, the Missouri General Assembly passed legislation authorizing the Missouri Department of Natural Resources (MDNR) to develop and submit a state CCR program to EPA for approval.

Also in 2018, EPA proposed revisions to the CCR Rule (Phase-One Rules) to address, in part, Congress's changes to RCRA and allow state directors to use risk-based processes similar to other existing solid waste program. Both the State of Missouri and Ameren filed public comments that support EPA's proposed changes. Copies of those comments can be accessed here.

EPA finalized the first phase of these CCR-related changes in July 2018, and the final phases are expected by summer 2019. Until a state CCR program is finalized and approved by EPA, MDNR can utilize its state-level cleanup program to approve closure and corrective measures at Ameren's ash basins.

Answers to Customer Questions
Ameren has been safely operating CCR storage facilities for decades. Below are answers to some frequently asked questions from the public about the comprehensive steps Ameren has taken to manage CCRs.

What is Ameren doing to close the ash basins?
Ameren is implementing a comprehensive plan to safely and responsibly close ash basins that exceeds requirements created by the Obama Administration’s Environmental Protection Agency (EPA) in 2015. These EPA regulations require Ameren to close CCR basins and develop steps to address any impacts to groundwater in the communities where we work and live.

Basins can be closed by either placing a cover system over the top, or by excavating them by dredging out the material. The EPA has long maintained it does not have a preference on closure methods, both of which are effective in protecting the environment. The agency expects most CCR basins across the country will close via installation of a cover system. Ameren has thoroughly explored and used experts to help assist, on how to best design and close the basins and limit impacts on the communities we serve and call home. As a result of that extensive analysis, Ameren plans to close the basins by installing a cover system that exceeds regulatory requirements. Safe, responsible closure using this method is the most efficient path to achieve the groundwater protection standards set under the federal rule. Ameren Missouri's plans are summarized in the Remedy Selection Report (PDF).

What happens next?
Excess water is removed from the basins and the ash will be compacted, graded and sloped to permanently shed water. After that, an engineered capping system, far stronger than regulations require, will be constructed over the top of the basins and the riverside embankment walls armored with rock. This system will take approximately two years to construct and isolate the ash from infiltration. Precipitation will be routed to newly-constructed storm water basins. The limited groundwater impacts localized to Ameren property will diminish over time, and experts are evaluating methods to accelerate this process. Further details are available here.

Are there impacts on public health?
No. As demonstrated in numerous reports over many years, expert sampling results demonstrate that Ameren's CCR units do not impact public drinking water sources that draw from the Meramec, Mississippi and Missouri Rivers. Additional expert testing of groundwater used by drinking water wells near energy centers also show no impact.

Are CCR basins stable and safe?
Yes. Energy center personnel inspect the basins weekly and annual inspections are conducted by specially trained dam safety engineers. Because of their construction and design, the CCR basins at Ameren’s energy centers are in no danger of collapse, as has happened elsewhere. The basins have thick walls and are constructed to withstand up to an 8.0 magnitude earthquake. Even in cases of extreme flooding, as seen in the spring of 2019, the basins performed as designed.

What studies have been done?
For the past several years, Ameren has commissioned dozens of environmental studies by certified toxicologists and other experts in their fields of study. These ongoing inspections of groundwater, drinking and surface water conclude there is no risk to public health. Additional studies, posted to this website, looked at excavation and transportation issues associated with basin closure methods.

How has the community been involved in the process?
Ameren held four public meetings, one each near the four energy centers in May 2019. Attendees asked questions and left written comments. Additional comments were received via email. Ameren notified media outlets and posted information about the public meetings on this website.

More information is available under each section header at the top of this page, or in the public meeting and technical details response (PDF).

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