The Trump Administration is back in the hot seat as a coalition of 23 states have joined forces to sue the government over its decision to lower fuel economy and emission standards.

Back in March, the Environmental Protection Agency and the National Highway Traffic Safety Administration unveiled the final version of the Safer Affordable Fuel-Efficient (SAFE) Vehicles Rule which set new corporate average fuel economy (CAFE) and CO2 emissions standards for 2021-2026 model year passenger cars and light trucks.

It called for 1.5% annual increases in CAFE and CO2 emissions standards through the 2026 model year. This is significantly lower than the 5% annual increases proposed by the Obama Administration in 2012.

Also Read: US Releases New Fuel Economy Standards, Aims For 40.4 MPG Instead Of 46.7 MPG

To put those percentages into useful numbers, the government has previously said the “projected overall industry average required fuel economy” in 2021-2026 model year vehicles would be 40.4 mpg. That’s 6.3 mpg less than standards proposed in 2012.

The massive decrease immediately sparked a firestorm, but the government claimed the lower standards would reduce the average price of a new vehicle by approximately $1,000 (£816 / €910), while also reducing regulatory costs by as much as $100 (£81.6 / €91) billion through the 2029 model year. The government also said the change would help to increase new vehicle sales by up to 2.7 million units through the 2029 model year.

The government went on to claim the lower standards would save lives as there would be approximately 3,300 less crash fatalities and 397,000 less injuries. The murky logic behind this is lower prices will allow more people to buy new vehicles, which are safer than older models, so less people will die.

Jumping back to today’s news, the lawsuit is being headed by California Attorney General Xavier Becerra who said the coalition will argue the rule violates the Clean Air Act, the Energy Policy and Conservation Act and the Administrative Procedure Act.

Becerra went on to say “The underpinnings for the Trump Administration’s so-called ‘SAFE’ rule are crumbling before the rule even hits the road. The Administration claims their new rule will save money and lives, but previously undisclosed internal documents reveal how far from the truth that is.” He went on to described the rule as a “job-killer and public health hazard” that will “increase costs to consumers and allow the emission of dangerous pollutants that directly threaten the health of our families.”

California is being joined by 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, Washington, and Wisconsin. The coalition also includes Denver, New York, San Francisco, Los Angeles and the District of Columbia as well as the California Air Resources Board and the Counties of San Francisco and Denver.

In related news, Reuters reports 12 environmental groups are also suing the government over their decision to lower fuel economy standards. That lawsuit includes the Center for Biological Diversity, Environmental Defense Fund, Sierra Club and Union of Concerned Scientists.

The Sierra Club counters the government’s claims and says the lower standards would “increase fuel costs by more than $240 billion (£195.8 / €218.1); result in 18,555 premature deaths; produce 1.5 billion metric tons of climate pollution; and contribute to one million lost work days.”