In 2008, the Tennessee Valley Authority’s Kingston Fossil Plant dumped 5.4 million cubic yards, or 1 billion gallons, of coal ash slurry into the local environment.

This was the largest U.S. industrial spill to date, and it prompted the Environmental Protection Agency to gradually form the first federal regulations on coal ash, the toxic residuals left over after coal is burned to produce electricity.

These regulations, which comprise the 2015 Coal Combustion Residuals Rule, required about 500 of the nation’s unlined coal ash surface impoundments to stop receiving waste and begin closing by 2021. The Trump administration allowed utilities to request extensions, but new officials are now taking action.

Last week, the EPA announced that it was going to begin enforcing these laws while working on plans for stricter regulations.

“The coal ash rule has been on the books since 2015. But with the entry of the Trump EPA, enforcement was off the table, and there was no federal oversight of the hundreds of utilities that had to comply with the rule,” said Lisa Evans, a senior attorney at Earthjustice who specializes in hazardous waste law.

The US has produced billions of tons of coal ash, which is an umbrella term for the various forms of coal combustion waste, in the past century. This waste contains nonbiodegradable heavy metals that, when ingested or inhaled, can cause cancer, disease and death.

Most of this waste has been stored in unlined and unmonitored ponds or landfills. Basically, utilities dug giant holes and dumped coal ash in piles that can exceed several hundred feet high. (Coal ash is also recycled to make concrete, wallboard and other materials.)

Courtesy Tennessee Valley Authority

In 2018, the Tennessee Valley Authority’s Allen Fossil Plant in Memphis had arsenic at levels 350 times what’s considered safe by the EPA in nearby groundwater.

The Tennessee Valley Authority has about a dozen of these unlined pits, including seven in Tennessee. In 2018, all of the coal ash sites had pollutants at levels higher than the EPA says is safe. The Allen Fossil Plant in Memphis had arsenic levels at 350 times the EPA maximum in local groundwater, according to a 2019 report that reviewed public data of groundwater wells near coal ash sites.

This report found that contamination affected more than 90% of the roughly 250 coal ash ponds across the U.S. that were monitored.

“There is significant groundwater pollution at almost every plant, and companies have not been honest in reporting that contamination,” Evans said. “It’s essential that these coal ash ponds be closed safely and don’t leave a legacy of pollution for neighboring communities.”

However, groundwater pollution could be worse. Because groundwater moves and spreads, a few monitoring wells near coal ash sites that can be hundreds of acres across is not sufficient to determine the exact nature and extent of the pollution, according to Evans.

About 30 miles east of Nashville and adjacent to the Cumberland River, TVA’s Gallatin Fossil Plant has an unlined coal ash pit. This site had 16 pollutants, like arsenic, cobalt and mercury, above safe levels in nearby groundwater in 2018.

“Because the coal pit is unlined, all of the contaminants from that coal ash can get into the groundwater, and from the groundwater, flow out into the river,” said Amanda Garcia, the Tennessee director of the Southern Environmental Law Center.

Most coal plants are located near rivers or lakes because they need a water source. Utilities burn coal to heat water, which becomes the steam needed to run through a turbine to produce electricity.

Gallatin is especially vulnerable due to its karst terrain. The city sits atop a limestone maze of cracks and crevices that readily connect surface water and groundwater, the valuable water below the Earth’s surface.

In 2017, a federal court ordered TVA to move the coal ash at Gallatin to a dry landfill. TVA said it’s currently in the permitting process for that site and others, including the Cumberland Fossil Plant.

“TVA is working with our regulators to finalize closure plans that are specifically tailored to each of our sites,” TVA said in a statement. “The EPA has determined two equally protective methods for closing coal ash impoundments – closure in place and closure by removal.”

Courtesy Environmental Protection Agency

Coal ash can affect groundwater and surface water.

Garcia said this overdue action from EPA might help address the issue of coal ash sites that have been drained but remain in contact with groundwater, which creates a continuing source of pollution, the EPA said in its announcement earlier this month.

“TVA has been dragging its feet,” she said. “After the Kingston spill, they committed to moving to dry storage of their coal ash. To the extent that they’re leaving coal ash in contact with groundwater at different sites across the state, from our perspective, that’s not a cleanup. That’s a coverup.”

In 2015, after the federal rule passed, the Tennessee Department of Environment and Conservation issued an executive order to assess and remediate all coal ash disposal sites in Tennessee.

The order went further than the federal rule by requiring TVA to address all coal ash sites, including current and former surface water impoundments, permitted landfills and non-registered landfills — the landfills that existed before they were subject to regulation. One criticism of the 2015 federal rule is that it doesn’t address the sites that were closed earlier than the rule went into effect, and environmental groups have said that could represent as much as half of all coal ash ever produced.

TDEC said the new announcement “does not affect” their current process, since the EPA actions taken thus far were directed at utilities outside of Tennessee.

Earlier this month, the Tennessee General Assembly introduced a house bill that would define coal ash and other coal combustion residuals as hazardous waste, instead of solid waste, which is the designation for household trash.