EPA settles with Public Service Company of Colorado for failure to meet coal ash regulations at Cherokee Generating Station

EPA settles with Public Service Company of Colorado for failure to meet coal ash regulations at Cherokee Generating Station

Settlement advances EPA's National Enforcement Priority of protecting communities from coal ash contamination

October 9, 2024

The settlement, finalized on September 30, is part of EPA's National Enforcement and Compliance Initiative, Protecting Communities from Coal Ash Contamination. This Initiative is needed given the breadth and scope of observed noncompliance with the federal coal ash regulations. Coal ash, which is produced from the burning of coal for energy, is a large industrial waste stream (by volume) and contains certain contaminants known to cause cancer and other serious health effects. Prior to 2015, the management and disposal of coal ash was not regulated at the national level; instead, it was regulated to varying degrees, if at all, by some states. Historically, coal ash was typically disposed in unlined landfills and unlined surface impoundments many of which are in contact with groundwater.

Without proper containment and management, contaminants from coal ash can pollute waterways, groundwater, drinking water and the air.The additional enforcement resources under EPA's National Enforcement and Compliance Initiative to address this issue will help protect both water sources, including drinking water, as well as the often-overburdened communities who live near these units.

"Today's settlement will protect Adams County, North Denver communities and the surrounding environment by ensuring that effective measures are implemented to address groundwater contamination at the Cherokee Station power plant," said KC Becker, EPA Region 8 Administrator. "We will continue to hold owners and operators of coal ash facilities accountable, restore the environment where damage has occurred and protect communities that have been disproportionately impacted by pollution."

PSCo converted Cherokee Station to a gas-fired plant in 2017 and removed all coal ash from the four coal ash surface impoundments at the plant in 2017 and 2018. PSCo has been conducting groundwater monitoring at the four closed impoundments and has determined that lithium has been released at levels requiring corrective action.

EPA alleges that PSCo did not meet certain requirements under EPA's coal ash program, including:

• Failure to adequately prepare annual groundwater monitoring reports;
• Failure to accurately represent background groundwater quality and use the most effective statistical methods to analyze groundwater data; and
• Failure to meet groundwater monitoring system performance standards.

The settlement requires PSCo to, among other things, develop and implement a remedy for the lithium releases from the coal ash impoundments and use EPA-approved statistical methods to continue monitoring groundwater at the other closed impoundments. In July 2024, PSCo finalized a report assessing measures that can clean up the lithium releases to groundwater. PSCo is gathering facility-specific data that will help determine which remedy will most effectively address the releases from the coal ash impoundments, and is monitoring groundwater at the fourth closed unit to ensure that action is taken if releases of contaminants are found above the levels established in EPA's coal ash program.

Read EPA's Consent Agreementand Final Order for the Cherokee Station.

In April 2015, EPA established national rules for coal ash management and disposal to address:

• Risks from disposal and discharge of coal ash, including leaking of contaminants into groundwater,
• Blowing of contaminants into the air as dust, and
• Catastrophic failure of coal ash surface impoundments.

These rules established a comprehensive set of requirements for the safe handling and disposal of coal ash from coal-fired power plants, including technical requirements for coal ash landfills and surface impoundments.

For more information on coal ash and the agency's coal ash program activities, please visit EPA's Coal Ash (CCR) website.