EPA proposes easing vehicle greenhouse gas regulations for automakers

EPA moves to drop greenhouse gas oversight

On August 21, 2025, the Environmental Protection Agency (EPA) proposed ending its regulation of greenhouse gases from new cars, trucks, SUVs, and commercial vehicles. The plan would cancel the 2009 Endangerment Finding, which labeled greenhouse gases as pollutants under the Clean Air Act and a danger to public health.

The proposal would remove rules requiring automakers to measure, report, or meet greenhouse gas standards if approved. Automakers would still need to regulate other pollutants, not carbon dioxide, methane, nitrous oxide, or hydrofluorocarbons.

Clean Air Act foundation for past rulings

Section 202(a) of the Clean Air Act directs the EPA to regulate emissions from new motor vehicles if they endanger public health or welfare. Until 2008, the EPA claimed it lacked authority to regulate greenhouse gases.

That changed when the Supreme Court, siding with Massachusetts and 18 other states, ruled the EPA did have authority. This led to the 2009 Endangerment Finding, where the administrator classified six greenhouse gases as pollutants under Section 202(a).

Trump order prompted agency’s review in 2025

On Jan. 20, 2025, President Trump signed Executive Order 14154 (Unleashing American Energy), directing agencies to reconsider energy-sector regulations, including those affecting vehicle emissions.

After Senate confirmation, new EPA administrator Lee Zeldin began reviewing the 2009 Endangerment Finding in line with the order.

Following this review, the EPA proposed rescinding greenhouse gas regulations. Virtual public hearings were held Aug. 19–22, 2025; the public comment period runs through Sept. 22, 2025.

EPA cites cost and industry jobs as reasons

The EPA says greenhouse gas regulations increase vehicle costs for businesses and consumers. It argues that higher truck costs raise the price of goods shipped across the country.

The agency also claims removing these rules will help “revitalize the American auto industry,” create jobs, and make it cheaper to build vehicles in the United States. Critics note that the EPA did not explain how this would work, as most automakers already spend money on research to meet global standards.

Smog checks remain required despite changes

The proposal would not end all emissions checks. The 2009 Endangerment Finding only covered greenhouse gases like carbon dioxide and methane. Other Clean Air Act sections still require the EPA to regulate pollutants such as carbon monoxide, nitrogen oxides, and particulate matter.

The EPA stated it is not reopening or changing emission standards for these pollutants or the National Highway Traffic Safety Administration’s fuel economy rules. However, the One Big Beautiful Bill Act, signed July 4, 2025, dropped penalties for violating fuel economy rules.

No past or present federal EV sales mandate

A federal mandate has never required automakers to sell electric vehicles (EVs). Regulations set under the Biden administration focused on raising fuel economy standards but did not specify how automakers must meet them.

Some officials and analysts described the standards as a de facto EV mandate because traditional engines might not meet them. California had its rule requiring all vehicles sold in 2035 to be zero-emission, but Congress rescinded its waiver, a move now being challenged in court.

Automakers may keep V-8 engines temporarily

The EPA proposal could extend the life of V-8 engines and other combustion models, as U.S. rules would no longer require stricter efficiency. Automakers could continue building existing engines without new costs.

Still, carmakers plan vehicles years ahead and must meet global standards abroad. Industry experts note the U.S. policy could shift again if Democrats win in 2026 or 2028. For now, some automakers may add larger engines to models for profit, but most will keep investing in hybrids and EVs.

EPA’s legal argument relies on reinterpretation

The EPA’s central claim is that regulating greenhouse gases under the Clean Air Act is unnecessary. It cites past Supreme Court rulings to argue its authority is limited to local or regional pollution.

Courts have already upheld the 2009 Endangerment Finding, and the Supreme Court declined to overturn those rulings. Section 202(a) gives the EPA authority to regulate pollutants that are judged harmful to health. Legal experts note that the EPA’s new stance depends on a narrow interpretation of the law and recent court shifts.

Agency questions climate science consensus

The EPA argues that scientific findings have changed since 2009, suggesting that climate data should be reevaluated. However, studies show agreement on human-caused climate change has grown stronger. A 2009 American Geophysical Union journal study found that 80% of climate scientists supported human-caused climate change.

By 2021, a study in Environmental Research Letters reviewed over 88,000 papers and found 99.9% agreement. The EPA also points to higher foreign emissions, but data show the U.S. remains the second-largest overall polluter and largest per capita.

EPA acknowledges harm but disputes severity

While pushing deregulation, the EPA admitted climate change is real and caused by humans, but claimed its effects are less severe than predicted. This contradicts its own case. Research shows that warming trends closely followed predictions from ExxonMobil scientists in 1977.

By arguing that the harm is overstated, the EPA confirmed that greenhouse gases affect public health, which meets the standard for regulation under Section 202(a). Its proposal also suggests reducing emissions may not fully solve the problem, a claim critics reject.

EPA offers multiple contradictory arguments

In supporting deregulation, the EPA accuses the 2009 administrator of misinterpreting science. It also claims that breaking up the analysis into parts affected the outcome, even though each part reached the same conclusion.

The agency argues that regulation is unnecessary because no perfect technology can remove all vehicle emissions. It also states that reducing greenhouse gases to zero would not impact climate change significantly. Critics note that the Clean Air Act does not require the total elimination of emissions; it only requires reductions.

MotorTrend tested 817 vehicles since 2012

MotorTrend, with U.K.-based Emissions Analytics, began real-world testing in 2012 to measure fuel economy and emissions. By May 2021, they had tested 817 vehicles using EQUA procedures similar to EPA methods. No vehicles showed Volkswagen-style cheating.

Gasoline cars averaged 0.023 g/mile of nitrogen oxides, less than half the legal 0.050 g/mile limit. Light- and medium-duty diesels from the last five years averaged 0.036 g/mile. Gas and diesel vehicles measured far below the 1.7 g/mile limit for carbon monoxide.

Carbon dioxide emissions remain a major issue

Testing showed that while pollutants like carbon monoxide improved, carbon dioxide emissions did not drop between 2012 and 2021. Hybrids with meaningful electric support reduced CO2 output because higher fuel economy lowers emissions.

Hybrid models boosted efficiency by 48%, cutting CO2 by about one-third. Diesel vehicles improved mpg by 25%, while compact, midsize, and large sedans made even bigger gains. Still, U.S. vehicles emit about 388 g/mile of CO2, leading to nearly 1.2 billion tons annually from light-duty vehicles.

SUV efficiency rises but total emissions stay high

SUVs, popular in the U.S., sit midrange in efficiency. Small gasoline SUVs averaged 24.1 mpg, while standard ones managed only 19.8 mpg. Over time, SUVs improved faster than the market average.

Testing showed SUV efficiency increased 0.7 mpg annually, compared to 0.2 mpg for the broader market. With about 300 million vehicles on U.S. roads, total CO2 emissions remain incredibly high despite improvements. MotorTrend calculated that over 11 billion tons had been released since the Real MPG program began.

Battery electric vehicles show high efficiency

Emissions Analytics tested seven battery electric vehicles on the same EQUA route. On average, they delivered 3.0 miles per kilowatt-hour, equal to 101 mpg-equivalent, four times higher than combustion vehicles’ 25.6 mpg.

The Hyundai Ioniq EV led at 4.5 miles/kWh, followed by the Chevrolet Bolt at 3.7. The least efficient were the Audi E-Tron at 2.1 and the Porsche Taycan at 2.2. Tesla’s Model S and Model 3 measured 3.0 and 3.1. The best EVs were twice as efficient as the worst.

Several well-known car models are returning with electric versions, giving a modern twist to classics. Check the details in popular models for getting an electric reboot.

EVs lower lifetime emissions but not zero

Battery electric vehicles emit no tailpipe CO2, but making large batteries produces significant emissions. A 36-kWh battery built for 130,000 miles of use equals about 80 g/mile of CO2. For comparison, combustion engines generate about 45 g/mile in production.

Adding grid electricity use, EVs average 150 g/mile—61% lower than gasoline cars and 37% lower than hybrids. If powered by a zero-CO2 grid, lifetime emissions could drop to 81 g/mile. Experts note that grid cleaning and EV manufacturing are vital for further progress.

The nationwide EV charging network is speeding up thanks to NEVI’s new fast-track rules. Read more about how the EV charging rollout accelerates under new NEVI fast-track rules.

What do you think about the EPA’s proposal—good for automakers or risky for the environment? Share your thoughts.

Read More From This Brand:

• Electrify America expands EV fast-charging network
• Chevy revives a classic muscle car in EV‑crossover form
• Are gas trucks gaining ground as EV adoption slows?

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This slideshow was made with AI assistance and human editing.