MONTGOMERY, Ala. (AP) — The U.S. Environmental Protection Agency on Thursday rejected Alabama’s proposal to take over coal ash regulation, saying the state plan does not do enough to protect people and waterways.

The agency said the state’s proposal was “significantly less protective” than required by federal regulations, and that it “does not require that groundwater contamination be adequately addressed during the closure of these coal ash units.”

“EPA is laser focused on protecting people from exposure to pollution, like coal ash, that can cause cancer risks and other serious health issues,” EPA Administrator Michael S. Regan said in a news release.

Coal ash is what remains when coal is burned to generate electricity. Coal ash contains contaminants such as mercury, chromium and arsenic associated with cancer and other health problems. States can assume oversight of coal ash disposal but must meet minimum federal requirements.

Alabama Department of Environmental Management spokeswoman M. Lynn Battle wrote in an email that the agency was reviewing the 174-page document and would comment later on the decision.

The EPA warned last year that it was poised to reject Alabama’s program, citing deficiencies in Alabama’s permits for closure requirements of unlined surface impoundments, groundwater monitoring and required corrective actions.

The Southern Environmental Law Center and other groups praised the decision.

“Today marks a significant victory for every Alabamian who values clean water,” Cade Kistler of Mobile Baykeeper said in a statement. “The EPA’s final denial underscores what our communities have said all along — that leaving toxic coal ash in unlined leaking pits by our rivers is unacceptable.”