MADISON, Wis. (AP) — A year ago, federal environmental regulators told West Virginia officials that their plan to clear sulfur and smog from skies over the state’s national wilderness areas wasn’t good enough because a dozen coal plants didn’t analyze whether they needed better pollution controls.

Six months later, the Environmental Protection Agency, now firmly under President Donald Trump’s control, blessed the same plan, saying technology evaluations wouldn’t be necessary as long as visibility hit projected benchmarks.

Conservationists say the about-face in West Virginia is just one example of the Trump administration clearing the way for states to roll back pollution restrictions that have helped clear the air over beloved national parks and wilderness areas over the last 25 years.

A rule has improved visibility, but Trump’s EPA says it’s too tough

A federal regulation known as the regional haze rule requires states to come up with plans every 10 years to limit emissions and monitor air pollution in more than 150 national parks, wilderness areas, wildlife refuges and tribal reservations across 36 states.

Since the rule took effect in 1999, more than 90% of parks and wilderness areas have seen sulfur and smog emissions decline by hundreds of thousands of tons annually. The average visual range has increased from 90 miles to 120 miles (145 kilometers to 195 kilometers) in some Western parks, according to the Harvard Law School’s Environmental and Energy Law Program.

But energy producers argue the regulations have done their job and are too costly. EPA Administrator Lee Zeldin announced in March 2025 that the agency would look to roll back 31 landmark environmental regulations, including the regional haze rule, to relieve regulatory pressure on the fossil fuel industry.

The EPA is still taking public comments on how to soften the federal rule. Meanwhile, conservationists say, the agency has weakened standards for individual state plans by rejecting state proposals the agency considers too tough on polluters and signing off on weak plans the Biden administration had rejected.

“They’re blessing states that haven’t done a good enough job and they’re dramatically changing course on states like West Virginia, like California, like Hawaii, like Colorado,” said Ulla Reeves, director of the National Parks Conservation Association’s clean air program. “They’re using these reversals and those changes to achieve their agenda of letting polluting facilities stay online.”

EPA spokesperson Brigit Hirsch said in a statement that the agency is committed to following the law and can’t approve state plans that don’t follow the law.