WASHINGTON (Reuters) - The U.S. Environmental Protection Agency (EPA) said on Wednesday it was reconsidering part of an Obama-era rule on emissions of mercury from coal-fired plants, in the latest move by the administration to ease regulations on an industry important to President Donald Trump’s political base.

FILE PHOTO: Exhaust rises from a coal-fired power plant in Union, Kentucky, U.S., September 14, 2017. REUTERS/Brian Snyder

Under the 2011 Mercury and Air Toxic Standards, or MATS, rule, coal plants have had to reduce emissions of mercury, a pollutant that can be dangerous to pregnant women and put infants and children at risk of developmental problems.

EPA spokeswoman Molly Block said the agency has issued a draft proposal on the rule that will soon be sent to the White House’s Office of Management and Budget, beginning a review process on the plan.

Block said the interagency process typically takes 60 to 90 days, after which the EPA expects to issue a proposed rule for public comment.

The MATS rule has forced coal plants to add pollution controls to their facilities and has been a factor causing plants to shut and driving down coal use to the lowest levels in decades.

The administration has taken steps to ease regulations on coal plants including replacing former President Barack Obama’s Clean Power Plan with a weaker plan. The administration has also ended a moratorium on coal leasing on federal lands and started withdrawing the United States from the Paris Climate Agreement.

Industry challenged the MATS rule and the case went to the U.S. Supreme Court which left it intact in 2015. But it sent one issue, the justification for creating the rule, back to a lower court, which sent it to EPA to ensure it had fully considered compliance costs.

In 2016, the Obama EPA found the costs justified as the rule saved consumers on healthcare bills, a finding that industry challenged.

One of several issues the EPA is assessing is “whether and how to account for co-benefits” in the rule, apparently referring to the Obama EPA’s position on the healthcare savings, Block said.

Jeff Holmstead, who headed the EPA’s air office from 2000 to 2005, said the agency was not seeking to do away with the rule altogether because the industry had already spent billions of dollars to bring plants into compliance.

Environmentalists criticized the move.

“This is outrageous and appalling,” said Mary Anne Hitt, who fights coal plants at the Sierra Club.

“The American people are not going to stand for (a MATS) repeal just to please a few millionaire coal executives.”