Here’s the release from Phil Weiser’s office (Lawrence Pacheco):

Attorney General Phil Weiser today joined a multistate coalition in filing a lawsuit challenging the federal government’s final rule rolling back the national clean car standards.

“The administration’s illegal rollback rejects sound science, ignores environmental harms caused by carbon pollution, and will cost consumers more at the pump. Colorado is joining this lawsuit challenging the administration’s illegal action in order to defend our state’s fuel emission standards that are stronger than the national standards,” Weiser said. “By making more zero-emission vehicles available to Coloradans, we can address climate change and protect our air quality.”

In 2010, the EPA, states and automakers established a unified national program harmonizing improvements in fuel economy and reductions in greenhouse gas emissions from passenger cars and light trucks and then applied those standards to vehicle model years 2017-2025. The administration took its first step toward dismantling the national clean car standards in 2018, alleging that the standards were no longer appropriate or feasible despite the fact that the auto industry was on track to meet them.

On March 31, 2020, the EPA announced its final rule rolling back the clean car standards. The rule takes aim at the corporate average fuel efficiency standards, requiring automakers to make only minimal improvements to fuel economy on the order of 1.5 percent annually instead of the previously anticipated annual increase of 5 percent. The rule also diminishes the requirements to reduce vehicles’ greenhouse gas emissions, allowing hundreds of millions of metric tons of avoidable carbon emissions into our atmosphere over the next decade.

In the lawsuit filed today, the coalition argues that the final rule unlawfully violates the Clean Air Act, the Energy Policy and Conservation Act, and the Administrative Procedure Act.

Attorney General Weiser joins the attorneys general of California, Connecticut, Delaware, Hawaii, Illinois, Maine, Maryland, Massachusetts, Michigan, Minnesota, Nevada, New Jersey, New Mexico, New York, North Carolina, Oregon, Pennsylvania, Rhode Island, Vermont, Virginia, Washington, Wisconsin, and the District of Columbia. The California Air Resources Board and the Cities of Los Angeles, New York, San Francisco, and Denver also joined the coalition in filing the lawsuit.

From The Denver Post (Bruce Finley) via The Broomfield Enterprise:

Led by California, the states and major cities — including Denver — have asked federal judges to reverse Trump’s Safer Affordable Fuel Efficient Vehicle Rule, which was finalized in March and loosened requirements set under the Obama administration to make cars and light pickup trucks about 5% more efficient each year.

Trump’s rule means vehicles over the next decade would emit hundreds of millions more tons of carbon dioxide and other heat-trapping gases into the atmosphere. Instead of making cars that can cover 54 miles per gallon by 2025, automakers could make cars that cover 40 mpg by 2026.

Federal officials argue this will make new cars more affordable, encouraging more Americans to upgrade to relatively cleaner cars.

This lawsuit, filed in the U.S. Court of Appeals for the District of Columbia Circuit, contends the Trump rule violates the Clean Air Act, the Energy Policy and Conservation Act, and the Administrative Procedure Act.

“We so depend on protecting our land, air and water for our lifestyle,” Weiser said in a conference call Wednesday with attorneys general Xavier Becerra of California and Dana Nessel of Michigan.

“Climate change is not a theoretical, looming challenge. It is there today,” Weiser said, referring to “less natural snowpack than ever before” and a growing burden on future generations to deal with climate change impacts.

He cited a U.S. Supreme Court case that, more than a decade ago, established EPA power to regulate pollution that causes climate change.

“It is the job of the courts to get the EPA on track,” Weiser said.

Denver Mayor Michael Hancock, in a prepared statement, noted that vehicle emissions are a top contributor to air pollution over the city and are fueling climate change — causing harm to the public’s health and prosperity.

“If these rules are rolled back, the Trump administration will negate the progress that has happened across the country in these areas during a critical point in history,” Hancock said. “We are past due for our country taking more meaningful action, which is why Denver joined this important lawsuit.”

In 2010, EPA officials, state leaders and automakers began working to improve vehicle fuel efficiency and reduce emissions of heat-trapping gases and other pollution from passenger cars and light trucks made after 2017. Automakers have been working to meet these standards. Since 2018, Trump administration officials have been saying the standards are inappropriate and no longer feasible.

Here’s a release about a coalition that has also filed a lawsuit from Environment Colorado (Ellen Montgomery, Hannah Collazo, Mark Morgenstein):

Environment America, an affiliate of Environment Colorado, along with ten other public interest organizations, filed a lawsuit today in the U.S. Court of Appeals for the D.C. Circuit opposing the Trump administration’s action to weaken federal clean car standards. This lawsuit follows litigation that Environment America and the other public interest groups previously filed challenging part one of the action, which attempts to block California and other states from setting stronger tailpipe emissions standards.

The petition challenges a final rule issued jointly by the Environmental Protection Agency (EPA) and the Department of Transportation’s National Highway Traffic Safety Administration (NHTSA). The agencies’ action violates several federal statutes, including the Energy Policy and Conservation Act, the Clean Air Act, and the Administrative Procedure Act.

“The EPA’s own analysis shows that this will reverse climate progress. The clean car standards should protect our climate, our health and the future of our children and grandchildren,” said Hannah Collazo, State Director with Environment Colorado. “This plan is unacceptable. Not only does it fail to adequately address the climate crisis — it sets us back years when we have no time to lose.”

The previous federal clean car standards would have doubled vehicular fuel economy and would have cut global warming pollution in half for cars sold in 2025. The weakened standards could result in more than 900 million additional metric tons of global warming pollution in our atmosphere.

The other petitioners are the Center for Biological Diversity, Communities for a Better Environment, Consumer Federation of America, Conservation Law Foundation, Environmental Defense Fund, Environmental Law & Policy Center, Natural Resources Defense Council, Public Citizen, the Sierra Club, and the Union of Concerned Scientists.