The Trump administration announced Wednesday that it is relaxing rules for the disposal of spent coal used to fuel hundreds of power plants nationwide.

But environmental groups say the rollback of coal ash storage regulations established by the Obama administration in 2015 could affect drinking water near dozens of sites.

Dalal Aboulhosn, Sierra Club’s deputy legislative director for land and water, said legal action was being considered. "We are poring through the rule change see what our next steps might be," she said.

The coal industry petitioned the Trump administration for the roll back, announced by Environmental Protection Agency Acting Administrator Andrew Wheeler — a former lobbyist for the coal industry.

In this April 2018, photo provided by the Environmental Protection Agency, Andrew Wheeler poses for a photo in Washington. EPA via AP

"It's not like EPA has granted us free pass here," said James Roewer, executive director of the Utility Solid Waste Advisory Group, an industry organization that had pushed for the changes. "It just gives us additional time to operate those facilities and better synch them up" with the upcoming wastewater guidelines.

The EPA states that the relaxed rules will save affected utility companies $28 to $31 million a year in regulatory costs.

"These amendments provide states and utilities much-needed flexibility in the management of coal ash, while ensuring human health and the environment are protected," Wheeler said in a statement. "Our actions mark a significant departure from the one-size-fits-all policies of the past and save tens of millions of dollars in regulatory costs."

The EPA extended the time by 18 months that the industry can use unlined coal ash ponds and groundwater-adjacent sites for dumping. The Obama administration sought to phase out those sites by April 2019.

The unlined ponds are considered by environmentalists to be the worst offenders for polluting groundwater that sometimes is tapped for drinking.

"The Trump administration is turing a blind eye to damage done to our drinking water," said Lisa Evans, senior counsel for environmental group Earthjustice. "This is aimed at saving industry money instead of protecting the public."