On Tuesday July 29, the U.S. Environmental Protection Agency
("EPA") announced a proposed rule to repeal its 2009 finding that greenhouse gas
("GHG") emissions from new motor vehicles contribute to
pollution and endanger public health and welfare (the
"Endangerment Finding"). EPA Administrator Lee Zeldin stated that should the repeal be finalized, it
would be "the largest deregulatory action in the history of
the United States." Zeldin also announced additional plans to
repeal "all greenhouse gas emissions that followed on light,
medium, and heavy-duty vehicles." EPA included a draft regulatory impact analysis for the
proposed rule.
What is the Endangerment Finding?
The Endangerment Finding has roots in CAA Section 202(a), which requires EPA to regulate
air pollutants if it finds that they "cause, or contribute to,
air pollution which may reasonably be anticipated to endanger
public health or welfare." 42 U.S.C. § 7521(a). In 2007,
the Supreme Court held in Massachusetts v. EPA that EPA has
authority to regulate GHG emissions as air pollutants under the
CAA. It also held that EPA was required to either determine
endangerment or provide a reasonable explanation for the absence of
such determination.
In 2009, EPA published its finding that six GHGs directly threaten
public health and welfare, and that combined GHGs from new motor
vehicles contribute to pollution that consequently threatens public
health and welfare. The GHGs identified were carbon dioxide,
methane, nitrous oxide, hydrofluorocarbons, perfluorocarbons, and
sulfur hexafluoride.
Analyzing EPA's Justifications and Potential Challenges
Facing the Proposed Rule
EPA put forward several theories to justify its proposed repeal of
the Endangerment Finding. One theory presented in the proposed rule
suggested that the Clean Air Act ("CAA") can no longer be
read to authorize the regulation of GHG emissions "based on
global climate change concerns" and instead should be read to
only authorize the regulation of air pollution that contributes to
endangerment of health and welfare through local or regional
exposure. Opponents will likely argue that the CAA imposes a
mandatory duty on EPA to regulate air pollutants, including GHGs
under Mass v. EPA, if they cause or contribute to air
pollution and endanger health, regardless of whether it is local,
regional, or global exposure.
EPA cites key Supreme Court decisions to support its rulemaking and
new interpretation of the CAA, including the landmark 2024 decision
in Loper Bright Enterprises v. Raimondo. However, Loper
Bright would seem to weaken the case for the proposed rule, rather
than strengthening it. If Chevron remained good law, EPA could
argue that the new interpretation of the Clean Air Act is plausible
and deserves deference. Under Loper Bright, EPA must demonstrate
that its new interpretation is the best reading of the statutory
language. That may be an uphill battle, particularly in light of
the Court's holding in Massachusetts v. EPA. In short,
Loper Bright likely increases the threshold EPA needs to
meet to repeal the Endangerment Finding as the Supreme Court has
spoken on its interpretation of ambiguous text in the CAA.
Further, EPA's reliance on three cases pertaining to specific
regulatory proposals is arguably also misplaced. Those cases are
(1) the 2022 West Virginia v. EPA, which found that
attempts to regulate GHG emissions from power plants were beyond
the authority Congress granted under the CAA; (2) the 2015
Michigan v. EPA, which found an EPA rule that limited
mercury and other toxic emissions from power plans improper for not
first considering compliance costs; and (3) the 2014 Utility
Air Regulatory Group v. EPA, which scaled back EPA regulations
of GHGs from stationary sources. Each of these cases addressed EPA
power to take specific regulatory actions, not its general
authority or obligation regulate GHGs.
Environmental groups are likely going to bring challenges to this
move. Opponents of the repeal could argue that the change in agency
position lacks a scientific and legal basis and so is
arbitrary and capricious. This argument is bolstered by courts
upholding the Endangerment Finding in several legal
challenges—including in the D.C. Court of Appeals' 2012
ruling in Coalition for Responsible Regulation, Inc. v.
EPA, which upheld EPA authority to regulate air pollution
under the CAA. Moreover, the Supreme Court denied cert to challenges to
EPA's use of the Endangerment Finding as recently as December
2023.
Notably, the 2022 Inflation Reduction Act amended the CAA to include language expressly
defining GHGs as pollutants subject to CAA regulation. Opponents of
the repeal may argue that the amendment reflects the type of clear
congressional intent that Loper Bright calls for. However,
these definitions are section-specific, and it will likely be
debated whether such definitions are controlling for purposes of
CAA Section 202(a) overall, particularly as the Supreme Court has
previously held "air pollutant" may have different
meanings in different sections of the CAA. See Utility Air
Regulatory Group v. EPA, 573 U.S. 302, 320 (2014).
Nonetheless, the statutory codification of GHGs as pollutants seems
to present a significant obstacle to EPA's proposed rule.
Impact of Repeal
Rescinding the Endangerment Finding would remove the legal basis
for EPA's existing GHG emissions regulations. This could lead
to the elimination of a number of sector-based regulations and
subsequent findings which rely on the endangerment finding as a
legal basis. For example, it could impact rules on light-duty passenger and commercial vehicles, large commercial aircraft, and fossil fuel-fired electric generating units,
among others.
EPA's proposed repeal stands in contradiction to last week's advisory opinion from the
International Court of Justice ("ICJ"). The ICJ held that failure by sovereign states to
reduce emissions could be an internationally wrongful act and found
that treaties including the 2015 Paris Agreement are legally
binding.
The elimination of the Endangerment Finding could also reinvigorate
nuisance suits brought by states against
emitters of GHGs. In the 2011 decision in American Electric Power Company v.
Connecticut, the Supreme Court ruled that, because the CAA
delegates the management of carbon dioxide and other GHG emissions
to the EPA, states were pre-empted in their suits brought
under federal nuisance law. Such preemption would stand even if the
EPA did not implement such regulations, so long as the CAA
authorizes such regulations.
However, the proposed rule suggests that the EPA "no longer
believes that [it has] the statutory authority and record basis
required" to implement GHG emission standards for light-duty,
medium-duty, and heavy-duty vehicles and engines under CAA Section
202(a). In future litigation, such a finding may undermine the
justification for preemption relied upon in American Electric
Power Co., re-opening the door for nuisance suits.
EPA has announced that a virtual public hearing shall be held on
August 19 and 20, 2025, with an additional session on August 21 if
necessary. Written comments on the proposal may be
submitted through September 15, 2025.
June Wang, a summer associate, participated in co-authoring
this blog post.
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