Industry and Republicans allege the EPA has acted in cahoots with green groups on that strategy as a way to impose new regulations without letting states get involved.
Environmental groups maintain that the lawsuits are designed to hold regulators to commitments for rolling out rules.
EPA said much of the same Tuesday, adding that it was reviewing the lawsuit.
“EPA has no input or control over what parties sue the agency or what issues they focus on. Furthermore, an outside entity cannot compel EPA to take an action that it was not already required to take by law,” agency spokeswoman Alisha Johnson told The Hill.
But the states, led by Oklahoma, said they're worried about foul play. They pointed to instances in which EPA filed a “consent decree” setting regulations in motion on the same day lawsuits were filed.
The 11 states that joined Oklahoma in the lawsuit are Alabama, Arizona, Georgia, Kansas, Michigan, Nebraska, North Dakota, South Carolina, Utah, Wyoming and Texas.
The EPA had previously denied those states a Freedom of Information Act request, and also rejected a request for a waiver fee.
Sen. David Vitter (R-La.), the top Republican on the Senate Environment and Public Works Committee, said Tuesday’s lawsuit showed the EPA is biased toward liberal groups.
“Looking at FOIA fee waivers, it’s clear that EPA favors far-left environmentalist groups over conservative think tanks, but today’s lawsuit is just another example demonstrating EPA’s discrimination extends toward States, as well,” he said in a statement.
This story was updated at 5:45 p.m.