EPA Moves to Cut Haze, Gets Hazed by States It's high season in the nation's national parks as millions of visitors come to see nature. If last year's visitor figures hold up - and early indications suggest they will - nine million visitors will see the Great Smoky Mountains, the most visited national park. Three other parks - Grand Canyon (more than four million visitors in 2011) Yellowstone (about three million) and Acadia (more than two million) - combined will attract roughly the same number. Yet many visitors likely to find their view of the natural landscapes softened, if not significantly obscured, by haze or smog from civilization. An amendment to the Clean Air Act passed 35 years ago was designed to ensure that when visitors get to their destinations, they are able to see the parks" vistas. For the better part of those years, there has been a tug of war between the owners of manufacturing concerns - particularly coal-fired power-plants - and the Environmental Protection Agency over how far the agency can go in requiring plants to cut down on three pollutants linked to haze: fine particles, which blur the air on their own, and sulfur dioxide and oxides of nitrogen, which break down into other smog-producing chemicals with the sun's help. The 1977 law, and a rule that followed it in 1999, are intended to protect visibility in 156 national parks and wilderness areas. The most recent survey of air quality in the parks showed that visibility was stable or improving in the vast majority of them. But it noted that if a place with bad visibility remains stable, that is not particularly good news. Now, working to avoid legal sanctions for excessive delays, the E.P.A. says it has approved 11 state cleanup plans and provisionally approved another 11 with small modifications that do not impose new requirements. It has also proposed to approve eight more state plans. In Colorado, the local power company, Xcel Energy and environmental groups like the Environmental Defense Fund worked together to produce a plan that met with the E.P.A."s approval. When that was announced, the state's congressional delegation gave an unusual bipartisan backslap to all. But the agency's proposals to toughen some of the requirements on power plants in the remaining 20 states have created a buzzsaw of opposition in places like Oklahoma, North Dakota and, most recently, Arizona. Those states are fighting back, arguing that the Obama administration should not be imposing major cleanup costs on electric generating companies when the overall economy is struggling and that the requirements could cause plant closings and eliminate jobs. Arizona's plan was partly rejected on July 3. The E.P.A. called for the installation of new high-end equipment to control the release of oxides of nitrogen from three large power plants: Cholla, Coronado and Apache. The agency said its proposal was intended to reduce nitrogen oxide emissions by 7,800 tons a year at Cholla, 4,700 tons a year at the Apache Generating Station and 4,500 tons a year at the Coronado Generating Station. "This proposal will make scenic vistas clearer while cleaning the air that Arizonans breathe," the E.P.A."s regional administrator for the Pacific Southwest, Jared Blumenfeld, said in a statement. In an e-mail, an agency spokeswoman, Enesta Jones, said the three plants "affect visibility at 18 national parks and wilderness areas, including the Grand Canyon, Mesa Verde and the Petrified Forest." Some of the plants are more than 100 miles from the parks involved, but with the right meteorological conditions in in the flat, dry landscape, a stream of smoke from the Cholla plant can be seen for many miles along Interstate 40. But Henry Darwin, director of that state's department of environmental quality, said the E.P.A."s requirements for the installation of six new pollution-control devices using selective catalytic reduction at the three plants were unnecessary. He said the resulting difference in haze at the Grand Canyon would not be discernible and that the agency's methods for drafting the requirements failed to include state officials in the process, allowing them only to comment after the fact. In an interview, he argued that the addition of the devices, which cost tens of millions of dollars apiece, would cause the cost of electricity will go up as well as the cost of water, which is moved throughout the state's elaborate plumbing system with electrical power. "I think they had a predetermined policy" of requiring the advanced technology, no matter the cost, Mr. Darwin asserted. The Navajo Generating Station on the Navajo Nation's reservation was not addressed in the recent E.P.A. ruling. Yet many expect that the agency will impose similar requirements on that plant, jeopardizing its continued operation and risking the jobs of Native Americans working there. The columnist George F. Will entered the fray last week, echoing arguments made by some Congressional Republicans in hearings that jobs are being sacrificed for imperceptible improvements in visibility. Opening a hearing last month, Representative James Lankford of Oklahoma, the chairman of a subcommittee of the House Government Oversight and Accountability Committee, said: "E.P.A. is attempting to federalize the program and imposing costs well beyond what the state had determined was necessary or justified. Ultimately, E.P.A."s proposal will costs billions of dollars for visibility improvements that are undetectable to the human eye." E. Scott Pruitt, Oklahoma's attorney general, charged in subsequent testimony that "with the backing of the Obama administration, the E.P.A. is engaging in super-legislative activity that Congress has not authorized, resulting in unchecked rule-making." Shortly thereafter, Mr. Pruitt was challenged by Robert V. Percival, who directs the environmental law program at the University of Maryland's law school. "There has not been any change in E.P.A. that has in any way cut out the public from the process," he said.