The Trump administration is considering whether to repeal or revise two major Obama administration regulations limiting air pollution from large sources.

Justice Department attorneys asked the Court of Appeals for the District of Columbia Circuit late Tuesday to delay scheduled oral arguments in two separate cases involving the Environmental Protection Agency (EPA) rules.

The most major action concerns the landmark 2012 Mercury and Air Toxics Standards rule, one of the most costly Obama administration rules that has been responsible for shutting down hundreds of coal-fired power plants.

ADVERTISEMENT

The EPA is reviewing whether it supports a 2016 regulation that the Obama administration wrote to fix a problem that the Supreme Court found when it ruled in 2015 that the EPA did not follow the law in writing the mercury rule.

“In light of the recent change in Administration, EPA requests continuance of the oral argument to give the appropriate officials adequate time to fully review the supplemental finding,” the attorneys wrote, adding that the prior positions taken by the agency with respect to the supplemental finding may not necessarily reflect its ultimate conclusions after that review is complete.”

The administration did not indicate whether it is reviewing the underlying 2012 rule.

But Earthjustice, which is representing numerous organizations in the litigation to defend the rule, slammed action, saying it is an attack on the mercury standards.

“These limits on power plant pollution, which have now been in place for two years, have cut power plants’ emissions and greatly reduced the threat to kids’ health and development,” James Pew, the Earthjustice attorney on the case, said in a statement.

“Scrapping them now would bring poisons back into kids’ lungs, blood, and brains and will cause thousands of people to die — prematurely and unnecessarily — from breathing in power plants’ soot pollution.”

ADVERTISEMENT

Scott Pruitt, now the EPA’s administrator, sued to stop the rule when he was attorney general of Oklahoma, labeling it part of the Obama administration’s “war on coal.”

The Obama administration had predicted that the rule would cost $9.6 billion, produce between $37 billion and $90 billion in benefits and prevent up to 11,000 premature deaths and 130,000 asthma cases annually.

The Supreme Court’s 2015 Michigan v. EPA decision said that the agency should have completed a cost-benefit analysis before deciding whether to write the regulation, but it did not overturn the rule. It did such an analysis, but only after deciding to proceed with the rulemaking process.

The 2016 regulation simply applied the existing cost-benefit analysis to the earlier step in the process. Conservative states, business groups and the energy industry challenged it in court.

The other regulation now under Trump administration review was written in 2015 to end an exemption that let some major pollution sources like power plants exceed emissions limits during startup, shutdown or malfunction.

The Trump attorneys made a similar argument in that filing, saying that the change of administration means the EPA may not support the rule anymore.

Since the regulations have been made final, any attempt to repeal them would have to go through a standard rulemaking process that could take a year or more.

The rule on startup, shutdown and malfunction exemptions applies specifically to 36 states that allow such increases in emissions.

Pruitt also challenged that rule as Oklahoma’s attorney general.

President Trump signed an executive order last month directing various agencies, including the EPA, to work to repeal nearly all of former President Obama’s climate change agenda, and to identify and remove barriers to production and use of domestic energy.

It did not mention either of the rules subject to Tuesday’s filings specifically.

The administration has already asked that federal courts hold off on numerous cases involving Obama regulations that it is reviewing, including those regarding carbon dioxide emissions from power plants, the jurisdiction of the Clean Water Act and ozone pollution.