(The Hill) – The Environmental Protection Agency (EPA) has issued notices to 15 states for failure to submit plans for air pollution reduction, four months after a lawsuit on the matter from a coalition of environmental groups.

In the lawsuit, originally filed in April, four organizations charged that the EPA had neglected to enforce the Clean Air Act’s Regional Haze rule by failing to notify states that had missed the deadline to submit an air pollution reduction plan. Plaintiffs included the Sierra Club, the Center for Biological Diversity, the Environmental Defense Fund and the National Parks Conservation Association. 

In a series of notices last week, the agency alerted the states that they had missed the deadline, officially starting the clock on a two-year window to either submit a late plan or accept an EPA-written plan.

The EPA rule requires all states to develop a plan to reduce air pollution that has an impact on visibility in wildlife refuges or national parks. In 2017, the deadline was extended to July 2021, meaning the states hit the six-month failure-to-submit threshold on Jan. 31.  

The states receiving notices are Alabama, Illinois, Iowa, Kentucky, Louisiana, Maine, Minnesota, Mississippi, Missouri, Nebraska, New Mexico, Pennsylvania, Rhode Island, Vermont, and Virginia. 

“The air pollution that causes haze in our national parks originates from sources that are often in the middle of communities that have suffered from decades of environmental injustices. EPA Administrator Regan saw these facilities and heard from these communities during his Journey to Justice. Enforcing environmental laws, and stepping in where states have failed to step up, is an important way for Administrator Regan to keep his commitment to these communities.” 

Holly Bender, senior director for energy campaigns at Sierra Club

A Sierra Club spokesperson told The Hill the group is still evaluating its options on the future of the lawsuit.