Despite bipartisan objection and industry pushback, the Trump administration is expected to soon weaken rules meant to limit mercury and other toxic emissions from oil and coal-fired power plants across the nation.

The EPA has already sent the Office of Management and Budget the final rule, which would repeal the Obama administration’s justification for the so-called Mercury and Air Toxics Standard or MATS, although it's not clear when it will be made public.

While the administration’s current efforts wouldn't withdraw the rule, it would change its legal basis with new calculations of costs and benefits, a move lawmakers, environmentalists, former EPA advisers and some in the energy industry warn would reverse the gains of the rule and damage public health.

“Ever since being elected to the Senate, I have worked to clean up our air. The Mercury Rule … has helped keep our air, waters and streams clean – and has been good for our state and its economy,” said Energy and Water Development Appropriations Subcommittee Chairman Lamar Alexander, R-Tenn.

The Obama administration estimated utilities would spend around $9.6 billion a year to comply with the rule, and that it would generate between $37 billion and $90 billion in public health benefits. According to the EPA’s analysis, the rule has helped cut mercury emissions by about 86 percent since 2010.