Sixteen states joined an effort this week to petition courts to review a rollback of an Obama-era regulation that capped the number of "glider" trucks, Transport Topics reported.

Glider trucks are new bodies fitted with older diesel engines that predate emissions controls. Those trucks can emit up to 43 times more carcinogenic particulate matter and 13 times more nitrogen oxides than currently allowed by law for new trucks.

Attorneys general from California, Delaware, Illinois, Maine, Maryland, Massachusetts, Minnesota, New Jersey, New Mexico, New York, North Carolina, Oregon, Pennsylvania, Vermont, Washington, and the District of Columbia asked a U.S. appeals court to consider the EPA's decision to stop enforcing a limit of 300 glider kit trucks per manufacturer.

The rollback of the glider truck rule was one of former EPA Administrator Scott Pruitt's final orders before he resigned amid multiple scandals.

The EPA hasn't yet responded to the court filing and didn't immediately respond to requests for comment.

Environmental groups such as the Sierra Club filed emergency motions earlier this month to challenge the EPA's proposed rollback and cited multiple studies that showed the harmful pollution created by the trucks.

In November 2017, Pruitt proposed reversing the rule and cited a study from Tennessee Technological University that initially stated that the older truck engines only polluted as much as new truck engines. The university eventually discredited its own study.

Pruitt then based his proposed rollback not on the study, but said that the EPA may not have the authority to regulate the trucks.

Many truckmakers including Volvo, Navistar, and Cummins oppose rolling back the regulation for glider trucks alongside health lobby groups such as the American Lung Association.