Conservation groups have filed a lawsuit demanding the U.S. Environmental Protection Agency force states to get moving on their obligation to clean up the air pollution overflowing into national parks, wilderness areas and wildlife refuges.

The lawsuit was filed Tuesday against EPA administrator Stephen L. Johnson in U.S. District Court for the District of Columbia on behalf of the National Parks Conservation Association and Environmental Defense Fund.

The lawsuit said EPA’s failure deprived conservation groups of the chance to examine and challenge the adequacy of state haze plans. It added that if state plans are inadequate, EPA is supposed to give them two years to do better or impose a federal plan.

“The findings we’re asking EPA to make basically will trigger a time clock for all other regulatory actions that need to happen in order for the standards to be met,” said Jennifer Chavez, a lawyer for the public interest law firm Earthjustice representing the plaintiffs. “Regardless of what needs to be done or how long it takes, if they don’t start it will never happen.”

EPA spokesman Nicholas Butterfield said the agency was reviewing the lawsuit and had no immediate comment.

The agency has said it expects the remaining state plans to be submitted this year or next, and that should not interfere with the deadline for meeting air quality goals.

The 1977 Clean Air Act required all 50 states to submit plans to EPA by December outlining how they would reduce the pollution that obscures views and diminishes air quality at protected federal lands that include national parks, congressionally designated wilderness areas, and national wildlife refuges. EPA developed rules in 1999.

The haze comes from emissions from motor vehicles, power plants, factories, wildfires, controlled burns and windblown dust. EPA has estimated cleaning it up will cost $1 billion to $4 billion and produce benefits of $3.5 billion to $10.8 billion.

So far conservation groups have been able to identify only 13 states that submitted plans, Chavez said. They are Arkansas, Alabama, Delaware, Iowa, Kentucky, Louisiana, Mississippi, Missouri, North Carolina, South Carolina, Tennessee, West Virginia, Utah.