WASHINGTON (AP) — The Environmental Protection Agency on Wednesday proposed repealing rules that limit planet-warming greenhouse gas emissions from power plants fueled by coal and natural gas, an action that Administrator Lee Zeldin said would remove billions of dollars in costs for industry and help “unleash” American energy.

The EPA also proposed weakening a regulation that requires power plants to reduce emissions of mercury and other toxic pollutants that can harm brain development of young children and contribute to heart attacks and other health problems in adults.

The rollbacks are meant to fulfill Republican President Donald Trump’s repeated pledge to “unleash American energy” and make it more affordable for Americans to power their homes and operate businesses.

If approved and made final, the plans would reverse efforts by Democratic President Joe Biden’s administration to address climate change and improve conditions in areas heavily burdened by industrial pollution, mostly in low-income and majority Black or Hispanic communities.

The power plant rules are among about 30 environmental regulations that Zeldin targeted in March when he announced what he called the “most consequential day of deregulation in American history.”

Zeldin said Wednesday the new rules would help end what he called the Biden and Obama administration’s “war on so much of our U.S. domestic energy supply.”

Environmental and public health groups called the rollbacks dangerous and vowed to challenge the rules in court.