Washington State

Office of the Attorney General

Attorney General

Bob Ferguson


Trump Administration attempts to block states from setting stricter vehicle emissions standards

SEATTLE — Attorney General Bob Ferguson filed a lawsuit today challenging the Trump Administration’s attempt to block Washington’s and other states’ ability to set more stringent vehicle emission standards.

“It’s time the Trump Administration stops denying the truth — climate change is real,” Ferguson said. “Our state is already witnessing the devastating effects of climate change, and adopting anti-environmental policies will only make it worse. I will not stand by while the Trump Administration’s actions put Washingtonians in danger.”

In the lawsuit, filed in the U.S. District Court for the District of Columbia, Ferguson and 23 other attorneys general assert that the National Highway Traffic Safety Administration (NHTSA) exceeded its authority and violated Congress’ intent when it issued a regulation declaring that federal law prevents states from setting more stringent vehicle emission standards. Ferguson and the states ask the court to declare that the regulation is unlawful.

The Clean Air Act sets federal standards for vehicles’ greenhouse gas emissions. The act allows California to set stricter emission standards for vehicles sold within state lines, provided the state applies for and is granted a waiver by the Environmental Protection Agency (EPA). The act also allows other states to adopt California’s standards. Washington, 11 states and the District of Columbia have adopted the stricter greenhouse gas emission standards.

This process has been in place for more than five decades — California obtained its first waiver in 1968. The EPA may deny the waiver only if it finds that the stricter standards are arbitrary and capricious, are unnecessary to meet clean air standards, or violate provisions of the Clean Air Act.

Blocking these states’ ability to set stricter greenhouse gas vehicle emission standards would prohibit them from following any standards other than those set by the federal government.

Legal arguments

NHTSA claims that the Energy Preservation and Conservation Act (EPCA), which sets fuel economy standards for vehicles nationwide, preempts California’s ability to set standards for greenhouse gas emissions from vehicles. The states assert that EPCA only governs fuel economy, not vehicles’ greenhouse gas emissions. Unlike EPCA, the Clean Air Act specifically governs greenhouse gas emissions and allows California the waiver.

In two separate cases, federal courts held that EPCA does not prevent California from setting its own greenhouse gas emission standards, nor does it prevent other states from adopting those standards.

Because the Clean Air Act governs greenhouse gas emissions, not EPCA, the states assert that the NHTSA does not have the authority to prevent California from setting greenhouse gas vehicle emission standards. They argue that NHTSA’s actions violate the federal Administrative Procedure Act, among other laws.

The states also assert that NHTSA did not assess the environmental impacts that its changes would cause, violating the National Environmental Policy Act and the Administrative Procedure Act.

Impacts to Washington

Washington and the states assert that preventing California from setting more protective vehicle emission standards will increase greenhouse gas emissions in their states, further exacerbating the impacts caused by climate change.                     

Washington experiences many negative effects of climate change, including rising ambient temperatures, a diminished and unpredictable snowpack necessary for water consumption and hydropower generation, and ocean warming and acidification, which are harmful to Washington’s shellfishery.

For example, the University of Washington Climate Impacts Group predicts that climate change will cause the sea level to rise and permanently inundate low-lying areas in the Puget Sound region, affecting approximately 4 million Washingtonians. The group also predicts that if no action is taken, climate change will lead to a 300 percent increase in the amount of land burned by wildfires in Eastern Washington.

According to the group, climate change will harm public health. All Washingtonians will likely face more frequent heat waves, more frequent and intense flooding, more wildfires and lower water supplies across the state.

Heat waves could lead to more hospitalizations due to heat stress, particularly for more vulnerable residents like children and those over the age of 65. More wildfires could lead to greater smoke exposure for Washingtonians, affecting respiratory health.

Washington enacted statutes and expended significant financial resources in reducing greenhouse gas emissions and slowing the pace of climate change.

Assistant Attorney General Emily Nelson is the lead attorney in the case for Washington.

California is leading the case. Other states joining the lawsuit include Colorado, Connecticut, Delaware, Hawaii, Illinois, Maine, Maryland, Massachusetts, Michigan, Minnesota, Nevada, New Jersey, New Mexico, New York, North Carolina, Oregon, Pennsylvania, Rhode Island, Vermont, Virginia, Wisconsin and the District of Columbia. Two cities — Los Angeles and New York City — also joined the case.



The Office of the Attorney General is the chief legal office for the state of Washington with attorneys and staff in 27 divisions across the state providing legal services to roughly 200 state agencies, boards and commissions. Visit www.atg.wa.gov to learn more.



Brionna Aho, Communications Director, (360) 753-2727; Brionna.aho@atg.wa.gov