The site of the Kingston Fossil Plant coal ash spill three years after the disaster.

This story was originally published by Mother Jones and is reproduced here as part of the Climate Desk collaboration.

The United States still relies on coal to provide 30 percent of its electricity, and a typical plant produces more than 125,000 tons of coal ash — the byproduct of burning coal — every year. For decades, power companies dumped this product, which can contain toxic metals such as arsenic and mercury, into unlined ponds that had the potential to leak and contaminate the drinking water of nearby communities.

Despite an EPA rule that requires power companies to dispose of the waste responsibly and monitor water quality near the dumping sites, coal ash continues to be a serious environmental concern. The rule regulating coal ash is weak and gives utilities the option to dump coal ash in landfills and old mines — often turning them into toxic waste sites. Many are located in and around marginalized communities without the power to fight back. Now, with an administration that’s hostile to environmental regulations in power, the coal ash problem is likely to get worse.

“These are all disasters waiting to happen,” says Frank Holleman, a senior attorney at the Southern Environmental Law Center.

The biggest disaster to date occurred in 2008 after a retaining wall surrounding the Kingston Fossil Plant collapsed, releasing more than 1 billion gallons into the Emory and Clinch rivers and the surrounding area. Mixed with the river water, the coal waste created a toxic sludge that destroyed or damaged 40 homes in a middle class, mostly white community.

The spill cleanup included trucking the spilled coal ash hundreds of miles away to Uniontown, Alabama, a predominantly black town where a large percentage of the population lives below the poverty line. Starting in 2009, the coal ash was dumped into a landfill, and local activists charged the leak with threatening community health and the surrounding environment. In 2016, the company that owns the landfill filed a $30 million defamation suit against four Uniontown activists who criticized the site. In February, the suit was settled and the company dropped their claim. Uniontown is stuck with the landfill — for now.

“A modern, lined landfill is tremendously safer than these water pits next to a river,” Holleman says. But some environmental justice advocates say that landfills are not always safe. “Any engineer will tell you,” says Lisa Evans, a senior attorney at Earthjustice, “all landfills leak.” When they leak, the toxic metals from coal ash can seep into the groundwater and contaminate drinking water sources.

In 2014, six years after the Tennessee spill, the EPA issued its final rule regulating coal combustion residuals, known as the CCR rule. Power companies would have to line their disposal sites to prevent…