Maryland Moves to Intervene in Lawsuits Defending Truck Emissions Regulations to Reduce Air Pollution

July 11, 2023

BALTIMORE, MD (July 6, 2023) – Maryland Attorney General Anthony G. Brown has joined a coalition of Attorneys General and cities in moving to intervene in lawsuits challenging decisions by the U.S. Environmental Protection Agency (EPA) that authorize California to establish regulations that would speed the adoption of zero-emission trucks and reduce emissions from fossil fuel-powered heavy-duty vehicles.

The regulations would help the states tackle climate and air quality challenges by reducing greenhouse gases, nitrogen oxides, particulate matter, and other emissions from medium- and heavy-duty vehicles. In the latest challenges, trucking and petroleum industry groups are among those challenging EPA’s decision to grant California’s request for “waivers of preemption,” which allowed these regulations to move forward in California and opened the door for other states to adopt them as well. Pursuant to the Clean Trucks Act of 2023, the Maryland Department of the Environment is finalizing regulations, which incorporate California’s standards by reference.


“Underserved communities bear the brunt of the most severe harms caused by climate change. That’s why I will fight for every action that reduces harmful emissions on behalf of all Marylanders,” stated Attorney General Brown. “Maryland’s own motor vehicle emission standards are rooted in California’s standards, which have played a significant role in promoting clean air nationwide. By defending and upholding these standards, we are fighting for clean air, public health, and a more equitable and sustainable future for every single person in our state.”

“Maryland stands with the coalition of states to demand that emissions standards match the urgency of improving the health of our communities with a just and equitable approach for those disproportionately affected by traffic and climate change,” said Maryland Department of the Environment Secretary Serena McIlwain. “Joining these lawsuits is consistent with Governor Wes Moore’s adoption of California’s Advanced Clean Cars II regulation and the need to reduce unhealthy emissions from trucks and heavy-duty vehicles.”

Under the Clean Air Act, California may request a waiver of preemption from the EPA to enforce emission standards for new motor vehicles that is more stringent than federal standards.

The EPA will then grant waivers, provided that certain statutory criteria are satisfied. While states are precluded from setting standards that are different than federal standards, states have the choice to adopt California’s standards or relying instead on federal standards.

Maryland is among the states that adopts California standards.

Joining Attorney General Brown in filing the motion to intervene are the Attorneys General of California, Colorado, Connecticut, Delaware, the District of Columbia, Hawaii, Illinois, Maine, Massachusetts, Minnesota, New Jersey, New York, North Carolina, Oregon, Pennsylvania, Rhode Island, Vermont, and Washington, as well as the Cities of Los Angeles and New York.