In a barrage of pronouncements on Wednesday the Trump administration said it would repeal dozens of the nation’s most significant environmental regulations, including limits on pollution from tailpipes and smokestacks, protections for wetlands, and the legal basis that allows it to regulate the greenhouse gases that are heating the planet.

But beyond that, Lee Zeldin, the administrator of the Environmental Protection Agency, reframed the purpose of the E.P.A. In a two-minute-and-18-second video posted to X, Mr. Zeldin boasted about the changes and said his agency’s mission is to “lower the cost of buying a car, heating a home and running a business.”

“From the campaign trail to Day 1 and beyond, President Trump has delivered on his promise to unleash energy dominance and lower the cost of living,” Mr. Zeldin said. “We at E.P.A. will do our part to power the great American comeback.”

Nowhere in the video did he refer to protecting the environment or public health, twin tenets that have guided the agency since its founding in 1970.

The E.P.A. has “no obligation to promote agriculture or commerce; only the critical obligation to protect and enhance the environment,” the first administrator, William D. Ruckelshaus, said as he explained its mission to the country weeks after the E.P.A. was created by President Richard M. Nixon. He said the agency would be focused on research, standards and enforcement in five areas: air pollution, water pollution, waste disposal, radiation and pesticides.

Mr. Zeldin said the E.P.A. would unwind more than two dozen protections against air and water pollution. It would overturn limits on soot from smokestacks that have been linked to respiratory problems in humans and premature deaths as well as restrictions on emissions of mercury, a neurotoxin. It would get rid of the “good neighbor rule” that requires states to address their own pollution when it’s carried by winds into neighboring states. And it would eliminate enforcement efforts that prioritize the protection of poor and minority communities.