Updated July 29, 2025 at 6:33 PM CDT
For years the Environmental Protection Agency has pushed carmakers to reduce how much vehicles contribute to climate change.
Today the EPA laid out plans to not just weaken those rules, but end them entirely.
In 2009, the agency determined that carbon dioxide and other greenhouse gases are a form of air pollution that the agency can regulate under the Clean Air Act. That's because those gases contribute to climate change, which harms human health.
That determination, called the "endangerment finding," underpins major regulations — including strict tailpipe standards for carmakers that envisioned at least half the new cars sold in the U.S. being electric or plug-in hybrids by 2030. The transportation sector is the largest source of direct greenhouse gas emissions in the United States.
President Trump campaigned against "electric vehicle mandates," and once in office, pledged to roll back such rules. Three sets of regulations that push companies to build cars that burn less gasoline — or no gas at all — were in his sights. His administration and Congress have already eliminated or weakened two of them.
Now, the EPA has published its proposal to revoke the "endangerment finding" and rewrite its tailpipe standards — meaning the third set of rules is poised to fall.
EPA Administrator Lee Zeldin announced the proposal at a truck dealership in Indiana on Tuesday, after previewing it on a conservative podcast. "We heard loud and clear the concern that EPA's GHG [greenhouse gas] emissions standards themselves, not carbon dioxide which the Finding never assessed independently, was the real threat to Americans' livelihoods," Zeldin wrote in a statement.
In the proposal, the EPA lays out multiple arguments for eliminating the standards. First, if carbon dioxide is not "air pollution" as traditionally understood, then EPA cannot regulate it. Alternatively, the agency says, even if the EPA could regulate it, there's not a good reason to do so, in part based on a report from five scientists who reject the scientific consensus on climate change.
The proposal won't immediately transform the auto market. It must now undergo public comment. If finalized, lawsuits are likely to follow. And automakers can't pivot their lineups on a dime.
Still, this proposal is a major victory for the oil companies and biofuel manufacturers who have long fought against these vehicle rules. The American Petroleum Institute welcomed the move on Tuesday, calling it "a critical step toward restoring consumer choice." It fulfills a campaign promise for President Trump, who has lambasted the regulations as increasing costs and limiting choice.
And it has horrified environmental advocates. Environmental Defense Fund president Fred Krupp wrote in a statement Tuesday, "if there are no enforced limits on pollution, you get more of it, making life more expensive and even more dangerous. The stakes could not be higher for Americans." Environmental advocacy group Moms Clean Air Force called the rollback "a shameful, reckless, and immoral move."
Three clean car standards – all of them being reversed
Vehicles in the U.S. have long been covered by three overlapping sets of efficiency and pollution rules.
The EPA regulates vehicle emissions through tailpipe standards. They govern how much pollution a vehicle can release while it's operating.
The Department of Transportation regulates fuel economy, or how many miles per gallon a car gets. Those rules are known as the CAFE standards, short for Corporate Average Fuel Economy, and are administered by the National Highway Traffic Safety Administration, or NHTSA. They require that the average fuel efficiency of new cars brought to market — across all the vehicles offered by a manufacturer — must meet a certain bar. That bar gets higher every year.
And because it was the first state to regulate vehicle emissions, well ahead of federal regulations, California has long been able to set its own rules that are tougher than the national standards. These include pollution standards and a rule mandating how many zero-emission vehicles carmakers must sell in the state. Other states can choose to follow California's rules, which wind up having a major influence on the auto market.
Over the past few decades, the combination of these three kinds of rules has pushed automakers to build cars that are significantly more fuel efficient and pollute less.
The Trump administration has taken major steps to roll back all three.
First, the administration asked Congress to revoke the EPA waiver that allows California to set the state's zero-emission vehicle mandate. That was an unprecedented move, and in May, Congress did as requested.
The federal CAFE standards, meanwhile, are still in place — for now. But the Department of Transportation is currently reviewing those rules, after stating that it costs automakers too much to comply with them, and that they drive up prices for consumers. Rewriting the rules "will lower vehicle costs and ensure the American people can purchase the cars they want," Transportation Secretary Sean Duffy wrote in a statement in June. (The regulations do increase the cost of cars, but consumer groups have repeatedly found they save drivers far more in fuel over the life of the car than they create in upfront costs.)
In the meantime, Congress has defanged the CAFE standards by removing the fines for carmakers who fail to meet them. That change, passed in the mega tax and spending bill that President Trump recently signed into law, could save hundreds of millions of dollars for automakers like General Motors and Stellantis that have chosen to make less efficient vehicles and pay the resulting penalties. And it removes the incentive for other automakers to comply; they face no consequences if they don't.
That leaves the EPA's tailpipe standards.
Under the EPA's proposal, tailpipe rules about pollution that directly harms human health, such as particulates, would remain in place; so would requirements for labels about fuel economy. But all the regulations related to cutting greenhouse gas emissions from cars would be removed.
Public comments and lawsuits
While the rollback of the California waiver and the elimination of CAFE fees have both been signed into law, the EPA's change is just a proposal. There will be a comment period, when companies, organizations and members of the general public can tell the agency what they think, and the EPA is required to take those comments into consideration before it finalizes any changes.
Public comments will be accepted through September 21, while a public hearing will be held in August.
The deregulatory push is also being challenged in court — and will almost certainly face more lawsuits.
California has sued over the revocation of its EPA waiver.
States and environmental groups have also asked the federal courts to review some of NHTSA's changes to the CAFE standards.
The Environmental Defense Fund has repeatedly sued the Trump administration over changes that weaken environmental protections. Asked whether this latest change is likely to prompt litigation, Vickie Patton, the group's chief counsel, paused for a moment.
"This would be one of the most damaging actions, really, ever taken in the history of the Environmental Protection Agency, if they move forward with an effort to just walk away from protecting the American people from some of the most dangerous pollution in our lives," she said, pointing to the ongoing effects of heat waves and fires made worse by climate change, in addition to smog and soot from vehicles. "It is EPA's responsibility to carry out the law and ensure that the American people are protected from harmful tailpipe pollution."
Uncertainty for automakers
Rolling back vehicle standards has long been a priority for the oil and biofuels industries, with focus on the issue intensifying as the rules grew stricter. In a statement last fall, the American Petroleum Institute called the standards an "intrusive government mandate," while the American Farm Bureau said it would "pull the rug out from underneath farmers" growing crops for renewable fuels.
The auto industry's position has been more nuanced, with the major automaker trade group the Alliance for Automotive Innovation stepping up a few years ago to defend the EPA's right to set strict standards — but also frequently pointing out that it would be far easier and more efficient to have one set of standards instead of three.
Recently, as EV demand grew more slowly than expected — now expected to be made worse by the administration's elimination of consumer EV tax credits — traditional automakers had been vocally warning that the Biden-era standards are unfeasible.
On Tuesday John Bozzella, the president of the Alliance for Automotive Innovation, issued a statement saying the group is "reviewing" the proposal "to understand what it means for U.S. vehicle emissions rules going forward." He added that "there's no question the vehicle emissions regulations finalized under the previous administration aren't achievable and should be revised to reflect current market conditions."
The trade group representing auto dealers, generally more skeptical of EVs than manufacturers, said that the existing rules would raise the cost of cars and trucks and that dealers "share the administration's concerns regarding vehicle affordability and customer choice."
Ford, in a statement emailed to NPR, said that it appreciated the work to address the "imbalance" between the current regulations and the market, adding: "America needs a single, stable standard to foster business planning."
Having a "stable" rule is a key concern for companies. While many automakers would welcome an easing of the rules, the flip-flopping between administrations and the drawn-out lawsuits create enormous uncertainty for them, even as companies have to make decisions about their product lineups five years or more into the future.
As for consumers, Beia Spiller, an economist and a fellow at Resources for the Future, a nonpartisan think tank, points out that drivers like having more efficient cars. "People would prefer to have a vehicle that costs them less to operate," she says. But, she says, research shows that new car buyers focus more on up-front prices (especially now, when those prices are so high) and under-value their future fuel savings.
That means market forces alone won't push cars to get clean as fast as regulations. So the rollback, in addition to increasing emissions, would also increase long-term fuel costs for drivers.
But, she says, it also wouldn't send the market into an immediate U-turn toward gas guzzlers. Automakers have made major investments in cleaner car technologies. Some of those investments might be reversed, and just written off as lost money; others might be carried forward. Even as EV sales flag, she says, hybrids, in particular, are likely to stay strong.
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