Millions of tons of coal ash produced by power companies each year will come under stricter controls of new federal regulations intended to prevent disasters such as the 2008 dike failure that released a billion gallons of toxic slurry into two Tennessee rivers.

The rules announced Friday by the Environmental Protection Agency will bring hundreds of coal-ash dumps under federal regulation for the first time, requiring extensive testing and monitoring of some disposal sites and forcing others to shut down.

But the regulations stopped short of classifying coal ash as “hazardous” waste, to the bitter disappointment of many environmentalists and community groups that have battled utilities over water contamination near some dump sites.

EPA Administrator Gina McCarthy said the new rules would reduce the chances of contamination from “mismanaged” coal-ash dumps that endanger neighborhoods through spills, leaks and drifting dust.

“These strong safeguards will protect drinking water from contamination, air from coal ash dust, and our communities from structural failures,” McCarthy said in a prepared statement.

The rules would force utilities to close and clean up sites that consistently fail to meet federal safety and engineering standards or are found to be leaking contaminants. New dump sites would have to include liners and other features to prevent toxins from escaping, said Mathy Stanislaus, the EPA’s assistant administrator for the Office of Solid Waste and Emergency Response.

“Any unit that cannot come into compliance would have to close,” he said.

Coal ash is the residue from coal burning and includes powdery fly ash as well as coarser bottom ash and boiler slag. Power plants across the nation produce about 140 million tons of the waste annually, recycling some of it as an additive in cement and other construction materials and dumping the rest in dry landfills or pondlike impoundments. Coal ash, which contains significant amounts of arsenic, mercury and heavy metals, was exempted from federal waste-management regulations by Congress in the 1970s.

The EPA has been considering new regulations for coal-ash disposal since the 2008 spill near Kingston, Tenn., which flattened several houses and caused fish kills in the Clinch and Emory rivers. A smaller spill earlier this year at a Duke Energy waste pond contaminated the Dan River near Eden, N.C.

Environmental groups had pushed the EPA to classify coal ash as “hazardous” waste, a designation that would have imposed far more stringent requirements for disposal and cleanup. Even if declining to label the waste as “hazardous,” the EPA could have banned storage ponds, which have spilled or leaked in scores of documented cases in the past two decades, said Lisa Evans, a former EPA attorney and expert on hazardous-waste law.

“Continuing to place communities in harm’s way is wrong,” said Evans, who now works for Earthjustice, a public interest law firm that sued the EPA over its failure to regulate coal ash. She called the EPA’s rule “extremely disappointing.”

Other environmentalists complained that the new rules require power plants to self-monitor their waste dumps, while leaving it to states and local residents to spot problems. While the EPA’s rule-making was long overdue, “it relies too heavily on the industry to police itself, ” said Eric Schaeffer, executive director of the Environmental Integrity Project.

Industry groups generally supported the EPA’s decision. Thomas H. Adams, executive director of the American Coal Ash Association, said a “hazardous” label would have made it harder to recycle coal ash, meaning more of it would go into landfills.

The decision “puts science ahead of politics and clears the way for beneficial use of ash to begin growing again, thereby keeping ash out of landfills and disposal ponds in the first place,” he said.