The EPA has taken its first major action to address toxic wastewater from coal-burning power plants, denying requests from three Midwest power plants to extend the operations of leaking or otherwise dangerous coal ash storage ponds.

The EPA said Tuesday that plants in Indiana, Ohio, and Iowa will have to close coal ash ponds months or years ahead of schedule due to deficiencies in groundwater monitoring or cleanup.

Coal ash, the substance left over after burning coal to generate electricity, contains a toxic mixture of mercury, cadmium, arsenic, and other heavy metals. It has the potential to pollute waterways, poison wildlife, and cause respiratory illness in people who live near massive ponds where waste is stored.

According to the EPA, a fourth industrial site, a former coal-power plant in New York State that now burns natural gas, is ineligible for an extension and will be forced to close early. The agency stated that a separate coal-powered plant in Kentucky will be required to fix groundwater monitoring as a condition for the continued operation of its coal ash pond.

The actions are the first time the EPA has put into effect a 2015 rule aimed at reducing groundwater pollution from coal-fired power plants, which has contaminated streams, lakes, and underground aquifers.

Coal plants in the United States generate approximately 100 million tons (90 million metric tons) of ash and other waste each year. For the first time, the Obama administration regulated the storage and disposal of toxic coal ash, including the requirement to close coal-ash dumping ponds that were unstable or contaminated groundwater. In 2020, the Trump administration relaxed the Obama-era rule, allowing utilities to use less expensive technologies and take longer to comply with less stringent pollution reduction guidelines than the agency originally adopted.

The actions announced Tuesday by EPA Administrator Michael Regan will ensure that coal ash ponds meet stringent environmental and safety standards, and that industrial facility operators are held accountable.

“I’ve seen firsthand how coal ash contamination can harm people and communities,” said Regan, a former North Carolina environmental regulator who negotiated the largest toxic coal ash cleanup agreement with Duke Energy, according to state officials.

“For far too long, communities already burdened by high levels of pollution have been burdened by improper coal ash disposal,” Regan said. “Today’s actions will aid in the protection of communities and the accountability of facilities.” We look forward to collaborating with our state partners to undo the damage that has already been done.”

The EPA denied requests for extensions of coal ash permits by the Clifty Creek power plant in Madison, Indiana; the James M. Gavin plant in Cheshire, Ohio; and the Ottumwa plant in Ottumwa, Iowa, in separate letters sent Tuesday.

Greenidge Generation’s Dresden, New York, plant was ruled ineligible for an extension. The former coal plant is now powered by natural gas.

The H.L. Spurlock plant in Maysville, Ky., has received conditional approval.

The enforcement action, according to Lisa Evans, a senior attorney for the environmental group Earthjustice, “sends a strong message to industry that (compliance with the EPA rule) is not a paperwork exercise.” It is necessary for them to clean up these toxic sites.”

Data released by utilities in 2018 revealed widespread contamination at coal plants ranging from Virginia to Alaska.