WASHINGTON — The Obama administration took steps Wednesday to cut levels of smog-forming pollution linked to asthma, lung damage and other health problems, making good on one of President Obama’s original campaign promises while setting up a fresh confrontation with Republicans and the energy industry.

In a long-awaited announcement, the Environmental Protection Agency said it prefers a new, lower threshold for ozone pollution of 65 to 70 parts per billion, but left open the possibility it could enact an even lower standard of 60 parts per billion sought by environmental groups. The current standard is 75 parts per billion, put in place by President George W. Bush in 2008.

Meeting the stricter rules will cost industry about $3.9 billion in 2025 if the government goes with a standard of 70 parts per billion, the EPA estimated. At a level of 65 parts per billion, the EPA said, the cost grows to $15 billion. But industry groups said the cost would actually be far higher and that it would be nearly impossible for refineries and other businesses to comply.

Pushing back on those claims, EPA Administrator Gina McCarthy said lower ozone standards would actually spur more businesses, investment and jobs by making communities healthier. She said states would be given time to carefully design plans to meet the new standard over the coming decades.

“We have had a lot of recent improvement in air quality in general,” McCarthy said. “We’ve done it before, and we’re on track to do it again.”

Business groups like the National Association of Manufacturers painted the government’s move as a roadblock that threatens to jeopardize manufacturing’s comeback in the U.S. They accused the administration of moving the goal posts, since states are still working to implement the previous standard put in place in 2008.

The EPA was under a court-ordered Dec. 1 deadline to issue a new smog standard. But the proposal also fulfills a pledge Obama made during his first campaign for the White House and one of his first environmental actions as president: reversing Bush’s decision to set a limit weaker than scientists advised.