Following the 2007 landmark Supreme Court case Massachusetts v. EPA, the United States Environmental Protection Agency (EPA) has regulated greenhouse gas (GHG) emissions from motor vehicles under the Clean Air Act. These emissions standards were significantly loosened in the last year of the Trump Administration. In 2021 the Biden Administration reversed the Trump-era rollbacks and instituted the strictest-ever vehicle GHG emissions standards in a move aimed at preventing 3.1 billion tons of carbon dioxide emissions by 2050.
In 2022, Texas, along with several other states and industry groups representing fuel manufacturers (together, Petitioners), challenged EPA’s new emissions standards in court. Texas Attorney General Ken Paxton has openly stated that the purpose of this litigation is to protect the fossil fuel industry, and the only representatives of the automotive industry in the case have entered to defend EPA’s new standards. However, Petitioners have argued that the new standards exceed EPA’s authority, were adopted in an arbitrary or capricious manner, and are otherwise barred by an expansive reading of the developing “major questions doctrine” because they may have nebulous effects on national security and electric grid reliability.
On March 2, the Sabin Center filed a brief in Texas v. EPA on behalf of the National League of Cities (NLC) and the U.S. Conference of Mayors (USCOM). The brief emphasized the threat that U.S. municipalities face from climate change, the special role that federal vehicle emissions regulations play in protecting municipal public health, and the threat that Petitioners’ radical interpretation of the major questions doctrine poses to the day-to-day operations of state and local governments.
The brief is available here. This blog post summarizes the history of federal vehicle emissions regulations, the arguments made by Petitioners in Texas v. EPA, and the response of NLC and USCOM in support of EPA’s new emissions standards.
I. Vehicle Emissions Regulation Under the Clean Air Act
A. History of the Clean Air Act
Vehicle emissions regulations in the United States have their origins in the Clean Air Act of 1963 (1963 CAA), which authorized the then Secretary of Health, Education, and Welfare to conduct research into vehicle exhaust pollution and propose legislation “to regulate the discharge of pollutants from automotive exhausts.” In its legislative findings, which remain in air quality statutes today, Congress justified air pollution regulation because “the growth of the amount and complexity of air pollution brought about by urbanization, industrial development, and the increasing use of motor vehicles, has resulted in mounting dangers to the public health and welfare.”
The research authorized by the 1963 CAA and the resulting recommendations culminated in the Clean Air Act of 1970 (1970 CAA), which set a regulatory agenda for the newly-formed EPA that included the first federally mandated vehicle emissions standards. Among many other statutory and regulatory pollution controls, the 1970 CAA required EPA to establish and periodically revise:
“standards applicable to the emission of any air pollutant from any class of new motor vehicles or new motor vehicle engines, which in [the EPA Administrator’s] judgment cause, or contribute to, or is likely to cause or contribute to, air pollution reasonably anticipated to endanger the public health or welfare.”
While the Clean Air Act (CAA) has been amended multiple times since 1970, this basic requirement has remained untouched. For the last 53 years, EPA has consistently set tailpipe emissions standards for new vehicle models under this regulatory program.
B. Massachusetts v. EPA Spurs Regulation of GHGs
In 1999, a group of private organizations filed a rulemaking petition asking EPA to regulate GHG emissions from vehicles under the CAA on the grounds that global warming caused by these GHGs endangered the public health and welfare. After soliciting public comments, EPA denied the petition, claiming that “the CAA does not authorize regulation to address global climate change,” that regulation of GHG emissions would impermissibly usurp fuel efficiency standards promulgated by the Department of Transportation, and that such regulation was unnecessary because then-President George W. Bush had already “established a comprehensive global climate change policy.”
The petitioners, joined by intervenor States and local governments, appealed this determination, and in Massachusetts v. EPA, 549 U.S. 497 (2007), the Supreme Court reversed EPA’s denial. The Court held that GHG emissions fit within the CAA’s definition of “air pollutant,” so “EPA can avoid taking further action only if it determines that greenhouse gases do not contribute to climate change or if it provides some reasonable explanation as to why it cannot or will not exercise its discretion to determine whether they do.”
In response to the Supreme Court’s decision in Massachusetts, EPA issued its “Endangerment Finding” in 2009, which concluded that “six greenhouse gases … taken in combination endanger both the public health and the public welfare of current and future generations.” Since then, EPA has consistently regulated GHG emissions from motor vehicles, although the scope of EPA’s GHG emissions regulations has been the subject of a political tug-of-war. The Obama Administration set the first vehicle GHG emissions standards in 2010 for vehicles manufactured in model years 2012 through 2016, and set revised standards in 2012 for model years 2017 through 2025. These standards required each automobile manufacturer to reduce the average emissions from its vehicle fleet by approximately 5% per year between 2012 and 2025. In 2020, the Trump Administration promulgated a new rule for model years 2021 through 2026 that reduced the required emissions reduction to only 1.5% per year.
In December 2021, the Biden Administration finalized its own motor vehicle emissions rule, which largely restored the Obama Administration’s standards between model years 2022 and 2026. Accounting for the significant deployment of “zero-emission” electric vehicles, the Biden Administration then set the most stringent motor vehicle GHG emission standards ever by lowering the emissions standard by more than 10% between model years 2025 and 2026.
II. Red-State AGs and Fossil Fuel Industry Groups Challenge the New Standards
In February 2022, Texas, along with fourteen other states and several industry groups representing fuel manufacturers, petitioned the D.C. Circuit to overturn the new regulations. Their briefs, which were filed in November, argued that EPA’s adoption of the standards was arbitrary and capricious and violated the major questions doctrine (among other things).
Petitioners’ primary claim is that the revised standards exceed the scope of EPA’s authority. In a somewhat perplexing argument, Petitioners claim that EPA lacks the statutory authority to base vehicle emissions standards on per-manufacturer fleetwide averages, rather than limiting the emissions of each vehicle, even though EPA has applied this approach since 1983. Petitioners also claim that, as the rule only regulates “tailpipe” GHG emissions, which electric vehicles do not produce, EPA is arbitrarily and capriciously failing to regulate the full lifecycle emissions of EVs. Petitioners argue that EPA is using its tailpipe emissions standards to require significant electrification of the transportation sector, exceeding its authority under the CAA and undercutting active political debate about electric vehicle policy.
Petitioners also argue that the potential economic and political ramifications of the standards are so great that EPA’s rule violates the so-called “major questions doctrine,” a relatively new and quickly evolving concept in administrative law. This doctrine was recently and prominently applied by the Supreme Court in West Virginia v. EPA, 142 S. Ct. 2587 (2022), which held that federal agencies must have “clear Congressional authorization” to adopt regulations that constitute an “unprecedented” or “transformative” use of their statutory authority. Petitioners claim that the new standards will increase electric vehicle use, which might increase both energy usage and demand for foreign minerals and manufacturing capacity. Petitioners argue that these hypothetical effects could have significant impacts on electric grid reliability and national security and so would represent an unprecedented expansion of EPA’s authority under the CAA.
In response, EPA argued, among other things, that the standards were well-within its statutory authority, that an incremental increase of an existing regulatory threshold did not trigger the major questions doctrine, and that the challengers, who are not regulated by the new standards, lack standing to bring this challenge.
III. National League of Cities and U.S. Conference of Mayors Weigh In, with the Sabin Center’s Support
On March 2, 2023, the Sabin Center filed an amicus brief in support of the Biden Administration’s new emissions standards on behalf of NLC and USCOM. While the EPA’s response brief addressed the Petitioners’ many doctrinal arguments at length, NLC and USCOM’s amicus brief highlighted the perspective of local governments on tailpipe emissions and vehicle electrification.
A. Cities Have Been at the Forefront of Climate Change
The brief by NLC and USCOM describes the ways in which cities are impacted by climate change, along with the many actions that local governments are taking to mitigate and adapt to climate change. More frequent and severe heat waves pose unique challenges for cities, in part due to the urban heat island effect, which can cause faster and increased warming in urban areas. Heat waves can also cause costly infrastructure damage in cities and exacerbate air pollution. Likewise, rising sea levels, hurricanes, and more frequent flooding is already causing billions of dollars of damage for municipalities, while threatening to displace millions of people in the United States by 2100.
Cities across the country are taking action to mitigate climate change and adapt to its effects. More than 180 local governments nationwide have committed to 100% clean energy, and many more have set ambitious renewable energy goals that fall short of a complete transition. Last year, local governments in the U.S. entered into more than 70 contracts to procure renewable energy, totaling more than 13,000 megawatts. And in 2022 alone, U.S. cities reported 847 separate climate adaptation actions. In many of the states challenging EPA’s emissions regulations, local governments are leading the fight against climate change.
The brief also highlighted the public health and environmental justice concerns that tailpipe emissions raise in cities. The ozone precursors and particulate matter that vehicles emit, in addition to GHGs, can contribute to a wide range of health problems, including childhood asthma, respiratory impairment, and cardiovascular disease. While many cities are taking steps to support electrification of the transportation sector, strict federal emissions regulations play a key role in reducing urban air pollution. Federal action is particularly crucial for low-income communities and communities of color, whose residents are more likely to live, work, or attend school near major roadways.
B. Petitioners’ Argument that the New Standards are Arbitrary and Capricious Ignores the Municipal History and Purpose of Vehicle Emissions Standards
The brief also responds to Petitioners’ argument that EPA was arbitrary and capricious in regulating only tailpipe emissions because this ignores the emissions from mining and power generation related to EV operations.
EPA’s practice of regulating tailpipe, rather than lifecycle, emissions under 42 U.S.C. § 7521(a) (the primary CAA section addressing motor vehicle emissions) was developed to address the unique regulatory challenge of concentrated motor vehicle emissions in urban environments. Emissions from vehicles cross jurisdictional borders. Community vehicular pollution levels reflect the aggregated emissions of the local vehicle fleet, and vehicle emissions are often concentrated in roadside or urban communities.
These unique characteristics of mobile emissions have shaped EPA’s emissions standards for the last 60 years. In a 1985 rulemaking, for example, EPA established a new regulatory category for “urban buses” because they are used primarily in cities and “make a significant and disproportionate contribution to overall urban particulate loading.” Congress endorsed EPA’s decision in the 1990 CAA amendments, which enshrined lower tailpipe emissions thresholds for urban buses. Although the Texas v. EPA Petitioners argue that EPA irrationally distinguishes “tailpipe” emissions from “lifecycle” emissions, Congress’s quick action on the urban bus standards makes clear that, for the purposes of the CAA, emissions are not created equal—mobile sources require carefully tailored regulation to mitigate concentrated urban emissions.
This regulatory focus is justified because tailpipe emissions pose unique public health harms to urban communities that municipalities struggle to abate on their own. Municipalities, sometimes in cooperation with their states, have significant authority to protect their residents from stationary emissions sources using legal tools like land use authority. However, they have little power to address tailpipe pollution because the CAA largely preempts local tailpipe emissions controls. As a result, while local governments have become “aggressively” involved in some areas of environmental regulation, they cannot protect themselves from vehicle tailpipe emissions in the same way. Instead, cities rely on EPA to regulate these emissions.
C. Petitioners’ Proposed Expansion of the Major Questions Doctrine Fundamentally Misunderstands How State Governance Works
Finally, the brief responds to Petitioners’ arguments that the Biden Administration’s new emissions standards are impermissible under the major questions doctrine because increasing the number of electric vehicles in the market might impact electric grid stability by increasing consumer electricity demands. Petitioners claimed that this would improperly infringe on areas of state and local governance, but this argument is completely unmoored from the reality of local governance. The American electrical grid is shaped by regulation at the federal, state, and local levels, which must constantly adapt to changing technologies and market consumption patterns. In fact, cities across the country are already planning their infrastructure around a future dominated by electric vehicles. EPA’s revised standards simply acknowledge the future that cities across the country are already preparing for.
Viewed in this light, the impact of EPA’s tailpipe emission standards on vehicle electrification is seen for what it is: a mundane effect of ordinary regulation. In practice, federal regulations nearly always overlap with and influence important areas of state and local policy. Federal regulation in one area often affects state and local regulation in another—national rules have local effects, and local regulators must respond to them—but that alone does not make them unlawful. EPA’s tailpipe regulations represent routine, Congressionally-mandated updates to regulatory thresholds and methodologies. If virtually any regulatory effort of this type may be undone by a court based on its secondary effects, local governments will be unable to build policy around federal programs.
IV. Conclusion
Since the earliest days of the CAA, federal vehicle emissions regulations have worked to protect American municipalities from motor vehicle air pollutants that threaten the public health and welfare. Since Massachusetts v. EPA, these regulated air pollutants have included greenhouse gasses that contribute to climate change—a growing threat to the health and welfare of cities and their residents across the United States. The Sabin Center is proud to support NLC and USCOM in defending EPA’s new vehicle emissions standards.
The full text of the Sabin Center’s brief is available here.
Martin Lockman is the Climate Law Fellow at the Sabin Center for Climate Change Law
