A group of physicians and environmentalists have filed a lawsuit against Maryland Gov. Larry Hogan alleging that he unlawfully blocked regulation that would have safeguarded Marylanders suffering from asthma, heart attacks and other harmful effects of ozone pollution.

Chesapeake Physicians for Social Responsibility and Sierra Club, represented by Earthjustice, filed the complaint in the Circuit Court for Anne Arundel County on June 11, naming Hogan and the Division of State Documents as defendants.

In one of his first acts as governor, Hogan withheld regulation adopted by the Maryland Department of Education on Jan. 16 that would have reduced smog-creating nitrogen oxide (NOx) emissions from coal plants. The governor issued a directive to the Division of State Documents blocking publication of the rule in the Maryland Register—a step necessary for final enactment of a law— and said it would be subjected to a comprehensive review, including a new round of public hearings.

In the lawsuit, however, plaintiffs say the nitrogen oxide regulation had already been subjected to a year-long stakeholder process, and another review could lead to a less protective standard. The complaint seeks to require the Division to publish the nitrogen oxide regulation and to prohibit Gov. Hogan from further blocking it.

“By blocking these critical public health protections, Gov. Hogan acted contrary to both public opinion and the law,” Michael Soules, Earthjustice’s lead counsel on the case, said in a statement. “The law is clear: once these safeguards were adopted, they were official and the new governor could not lawfully block them.”

Hogan’s actions caused the Maryland Department of the Environment to issue emergency regulation last month to reduce nitrogen oxide emissions for this year’s ozone season. But complainants say that is not enough.

“We’re going to hold the Governor accountable in court, because no one should have to breathe dirty air when the solutions already exist,” said Maryland Sierra Club Director Josh Tulkin. “For the sake of our health, these dirty plants need to install state-of-the-art pollution controls, repower to cleaner fuel, or retire by the end of the decade.”

To read a copy of the lawsuit, click here.