"The law on the books says we need to deal with the pollution choking our national parks," said Matt Elliott, the Pennsylvania and Delaware program manager with the National Parks Conservation Association, one of the groups that sued. "The Commonwealth and the EPA alike have turned a blind eye to their duty."
The other groups are the Sierra Club, a national advocacy organization, and the Clean Air Council, based in Philadelphia.
Haze is formed by sulfur dioxide, nitrogen oxides, and particulate matter.
Charles McPhedran, an attorney with Earthjustice, a nonprofit national environmental law organization, who represents the groups, said Pennsylvania came up with a haze plan, as required, several years ago.
Pennsylvania identified 33 sites as sources, including coal-fired power plants, cement kilns, refineries, and paper mills.
But Pennsylvania required none of them to reduce their emissions of the chemicals because they already had what the state considered "best available" technology in place, McPhedran said.
The EPA initially approved the plan, reconsidered when several groups objected, then issued a final approval on April 30.
"We believe that's flawed," McPhedran said. "These sources have impacts downwind, and EPA needs to require better controls."
The suit was filed in federal appeals court in Philadelphia.
Neither the EPA nor the state Department of Environmental Protection responded to requests for comment.
Thomas Schuster, a representative for the Sierra Club's Beyond Coal campaign, said the state's coal plants should not get a "free pass" to pollute.
Joseph O. Minott, executive director of the Clean Air Council, said the haze plan reflects an overall "attitude that Pennsylvania has about exporting its dirty air. Pennsylvania is very quick to point the finger at Ohio and West Virginia . . . for the dirty air that comes into Western Pennsylvania. But it is absolutely unwilling to recognize the air pollution that leaves Pennsylvania."
"It needs to be more responsible," he said. "It needs to step up to the plate and deal with its pollution."