Hundreds of inactive coal ash disposal sites across the U.S. could become subject to federal safety regulations under a new rule proposed by the U.S. Environmental Protection Agency.

The proposal, published in the Federal Register May 18, would apply to inactive surface impoundments—ponds, landfills and other fill sites—located at coal-fired power plants that ceased operation or no longer accepted coal ash waste prior to implementation of the agency’s 2015 rule governing management of coal combustion residuals facilities. 

That rule exempts such inactive and legacy disposal sites from federal monitoring, closure and cleanup requirements—even though some have been identified as the source of groundwater contamination through leaks and structural failures. 

Following a 2018 federal appeals court ruling vacating the exemption, EPA began collecting information that led to the proposed rule change, which will apply to more than 260 disposal areas at 141 different facilities across the U.S. Nearly 30 currently regulated residuals landfills also must comply with stricter management standards. 

EPA Administrator Michael S. Regan said in a statement that the regulation will particularly benefit lower-income and minority communities that historically have been disproportionately affected by pollution from disposal sites.

“It will reflect our broader commitment to reduce pollution from the power sector in a way that ensures a reliable, affordable supply of electricity,” Regan said. EPA does not anticipate any effect on current power plant operations, as the proposal applies to legacy contamination and coal ash disposal units that are no longer in use. 

The Utility Water Act Group, a non-profit group of energy companies and trade organizations that has been critical of federal coal ash regulation and worked to loosen the 2015 coal ash site rules during the Trump administration, did not respond to ENR’s request for comment. Desmarie Waterhouse, senior vice president and general counsel for the American Public Power Association, a grouo member, noted in a statement that her organization is reviewing the proposed rule, “keeping in mind that any EPA action in this area must be cost-effective, flexible, practically/technologically achievable and conscious of market trends.”

Some groups that have advocated for stricter oversight of coal ash disposal sites feel the proposed regulation does not go far enough. Environmental non-profit Earthjustice, which has led coal ash landfill litigation efforts in several states, estimates that dozens of potentially hazardous coal disposal sites remain exempt from federal regulation. They include disposal ponds that were dry when the 2015 rule went into effect, and landfills at former coal-fired power plant sites that do not also have legacy ponds. 

“EPA must close the loophole tightly, so utilities cannot avoid cleaning up any toxic waste,” said Earthjustice Senior Counsel Lisa Evans in a statement. “It doesn’t matter when or where it’s been dumped; it needs to be dealt with.”

EPA will accept comments on the proposed rule through July 17 and expects to finalize a regulation by spring 2024.