The dispute comes as the EPA prepares first-ever regulations for the disposal of coal ash in the wake of the catastrophic Tennessee Valley spill that dumped 5.4 million cubic yards of the sludge into the Emory River two years ago.

The agency is considering two proposals. The first would give the toxic residue a “hazardous” label and impose new federal regulations for construction of containment facilities. The second option, heavily favored by industry supporters, would classify the substance as “non-hazardous” and encourage facilities to recycle their coal ash into building materials like cement and drywall.

The Environmental Integrity Project, Earthjustice, and the Stockholm Environment Institute’s U.S. Center released an analysis of the EPA’s findings Wednesday claiming that the agency has exaggerated the value of coal ash recycling. The EPA stated in its report that the practice is worth $23 billion in health benefits, pollution avoidance, and lowered energy costs. The groups estimate the annual worth of coal ash recycling to be $1.15 billion while posing serious risks for the environment and human health.

“The concern we have is so loudly exaggerating the economic benefit of coal ash recycling,” said Eric Schaeffer, director of the Environmental Integrity Project, according to Bloomberg. “The noise that creates has sort of drowned out the concern over health and safety of properly disposing this kind of material.”

The groups voiced their support of the stricter program, which they say would protect communities near power plant-operated coal ash containment ponds.

They also noted in a statement Wednesday that there are as many as 50 unregulated coal ash dumps around the country similar to the one that broke down in the Tennessee Valley two years ago.

EPA spokeswoman Betsaida Alcantara said the agency would review the report along with over 400,000 public comments submitted to officials.