A federal judge has dismissed cases brought by two counties in Utah and Florida alleging Volkswagen's emissions fraud violated their state environmental laws.

U.S. District Judge Charles Breyer of the Northern District of California, who is overseeing the Volkswagen emissions litigation in San Francisco, found on Monday that environmental claims brought by Salt Lake County and Hillsborough County were pre-empted by the U.S. Clean Air Act. The ruling, which expanded on an Aug. 31 order from Breyer in a similar case brought by the state of Wyoming, could impact dozens of other environmental lawsuits in which at least eight states and 28 counties in Texas allege statutory damages in the billions of dollars.

“This is the type of conduct that Congress intended EPA to regulate,” Breyer wrote, adding that “if the counties were permitted to regulate this conduct, the size of the potential tampering penalties could significantly interfere with Congress' regulatory scheme.”

In fact, he noted, the potential penalties “could dwarf those paid to EPA.”

Volkswagen spokeswoman Jeannine Ginivan wrote in an email: “Volkswagen welcomes this decision and will continue to seek the swift dismissal of similar state and local environmental claims, which as affirmed twice by Judge Breyer, the federal judge overseeing the Volkswagen MDL, are preempted by federal law.”

Volkswagen was represented by Robert Giuffra of Sullivan & Cromwell.

Plaintiffs attorney Archie Grubb, who represented both counties, said that although “the impact could be persuasive,” Breyer's ruling is not binding in state courts, where most of the other government cases are pending.

“We recognize these are pretty novel issues that haven't come up before. And we think reasonable minds can disagree,” said Grubb, a principal at Beasley, Allen, Crow, Methvin, Portis & Miles in Montgomery, Alabama. “We certainly respect Judge Breyer's ruling, but we're evaluating our options figuring out if we want to move forward with an appeal or bring it to an end.”

The government cases are among a handful of lawsuits remaining after Volkswagen reached numerous settlements relating to its 2015 admission that it installed defeat devices in nearly 600,000 “clean diesel” vehicles in the United States that were designed to cheat emissions tests.

The cases are separate from a $14.7 billion agreement Volkswagen reached in 2016 to resolve consumer class actions that includes a $2.9 billion environmental mitigation fund. They're also separate from the $4.3 billion in criminal and civil penalties Volkswagen paid to the federal government.

A year ago, Volkswagen reached a $157 million settlement of environmental claims brought by 10 states, including Connecticut, Delaware, New York and Pennsylvania, which have laws similar to those of California—the only state allowed to set its own emissions standards apart from the U.S. Environmental Protection Agency.

The remaining cases involve states that don't have environmental laws similar to California's but can impose statutory penalties on automakers for tampering with the emissions of cars already on the road.

In the Wyoming case, Breyer found that the Clean Air Act still pre-empted the state's claims because Volkswagen had installed defeat devices during the manufacturing process prior to the cars going on the road. Jefferson County Circuit Court Presiding Judge Joseph Boohaker relied on that decision in granting dismissal of the state of Alabama's case against Volkswagen on Dec. 18.

The counties attempted to skirt the Wyoming decision by insisting that Volkswagen also tampered with used vehicles when it installed the defeat devices during recalls prior to 2015 to fix emissions problems.

They cited an April 11 decision by Travis County District Judge Tim Sulak who refused to dismiss claims involving recalled vehicles in a case that Harris County, Texas, brought against Volkswagen.

“We knew he was not going to reverse himself on the Wyoming issue, but we hoped he'd look at the issue with respect to cars that were recalled and then retrofitted with defeat devices and saying those were not pre-empted,” Grubb said.

Breyer saw no distinction, concluding that the EPA was best suited for handling emissions violations that spanned entire vehicle models.

“If a mechanic removes or alters a vehicle's emission control system during routine maintenance, for example, states and counties are in the best position to penalize that conduct,” he wrote. “But when the tampering at issue involves thousands of vehicles, and the changes are made through software updates instituted on a nationwide basis, EPA is in a better position to regulate that conduct, as it can rely on the tools Congress has given it to police vehicle manufacturers' compliance with emission standards before and after vehicles are put in use.”