Several environmental groups filed suit claiming that EPA approved Oklahoma’s coal ash permitting program without sufficient public participation and that a subsequent D.C. Circuit ruling vacating portions of EPA’s 2015 coal ash regulations undermined the foundation of Oklahoma’s program. Among the asserted defects of Oklahoma’s program is the claim that its coal ash permits do not expire and do not have to be amended to incorporate future changes in federal regulations and that the program would allow unlined coal ash impoundments to operate indefinitely. The complaint also alleges that the rule does not create minimum public participation guidelines for approved state programs that the plaintiffs claim are necessary under the Resource Conservation and Recovery Act.