Utah regulators were still brainstorming ideas for dealing with a nationwide ozone-pollution crackdown when, on Thursday, the U.S. Environmental Protection Agency announced plans to tighten the health standard even more.

Cheryl Heying, director of the Utah Division of Air Quality, said lowering ozone pollution will require Western states to work together on solutions. At least some ozone pollution drifts from state to state, from Los Angeles ship docks to Zion National Park and from California wildfires to the Wasatch Front, she said.

"It's important to make sure we have a healthy environment," Heying said, "but this is going to be tough to implement."

Nearly two years ago, the Bush administration announced limits on smog that were slightly stricter than ones that had been in place since 1997.

But 11 states and environmental groups sued. They charged that the Bush administration standard of 75 parts per billion did not properly take health effects into account because it ignored the recommendation of the EPA's own science panel, which suggested limits in the 60-70 ppb range.

On Thursday, Lisa Jackson, the EPA administrator under President Barack Obama, announced her agency had re-examined more than 1,700 scientific studies and public comments from the 2008 decision and is reconsidering the lower smog limit.

"EPA is stepping up to protect Americans from one of the most persistent and widespread pollutants we face," Jackson said, calling smog "a very serious health threat" that also harms the environment and economy.

"Using the best science to strengthen these standards is long overdue action that will help millions of Americans breathe easier and live healthier."

The EPA estimates the health benefits to be between $13 billion and $100 billion -- by reducing premature death, asthma, bronchitis, medical visits and missed work and school. The costs of cleaning up ozone are estimated between $19 billion and $90 billion.

National groups had a predictably broad range of opinions about the EPA's plan. The American Lung Association applauded it. The American Petroleum Institute panned it.

Two Utah organizations that weighed in before the 2008 ozone decision are also expected to participate during the 60-day comment period for the latest proposal.

Utah Moms for Clean Air previously urged EPA to adopt ozone limits close to 60 ppb. Co-founder Cherise Udell said regulators have a moral obligation to address the health effects of ozone.

"It is urgent and imperative that we have government intervention," she said. "It's unfortunate, but it's imperative [because if regulators] are not doing that, they are not doing their job."

The Utah Manufacturers Association still holds that tougher standards should only be adopted if there is proof that the health benefits will outweigh the economic burden of tougher ozone controls.

If the standards get "too oppressive," industry and the state's economy will suffer, said UMA President Tom Bingham.

"We just want to make sure," he said, "that everyone does their part."

Heying noted that it's impossible now to say how ordinary Utahns or their industries might be asked to help solve the state's problem. Until two years ago, the state met the federal ozone limits -- though barely -- and regulators had a few more years to come up with a comprehensive smog-reduction strategy.

But now as many as nine counties, from three corners of the state, have to deal with ozone, and reducing it won't be as simple as pointing a finger at smokestacks or drivers.

Based on what Western states learned during their decadelong efforts to reduce regional haze, wind spreads the West's pollution around.

As an example, Heying pointed to ozone data on national park areas. Craters of the Moon in Idaho, Mesa Verde in Colorado, Yellowstone in Wyoming and Dinosaur National Monument in Utah all have ozone levels that exceed what EPA says is healthy. And all of them can blame that pollution -- at least in part -- on Pacific ports and wildfire smoke that are beyond their control.

That makes ozone not just an issue for states, but a problem requiring regional, national and even international coordination. The group of states that worked together on haze in the West's national parks have already reorganized to tackle this issue, Heying added.

"We have to target each one of these [ozone factors] and not point fingers, she said. "We all have our sources of pollution, but it's everywhere."