The Environmental Protection Agency has delayed a decision on regulating coal ash waste from power plants.
The agency said in a statement Thursday that it's extending a Dec. 31 deadline because it is "still actively clarifying and refining parts of the proposal." It did not set a new deadline.
A massive spill at the Tennessee Valley Authority's Kingston power plant last year brought attention to how coal ash produced by generating electricity is stored. Some environmental groups want the EPA to regulate it as hazardous waste.
EPA says the spill is "regarded as one of the worst environmental disasters of its kind in history."
The agency told Congress this month that pollutants remain elevated but acceptable in treated drinking water around the spill site.