On February 12, 2026, the U.S. Environmental Protection Agency (EPA) issued the final rule rescinding the agency’s 2009 Endangerment Finding for greenhouse gases (GHGs). The 2009 Endangerment Finding concluded that GHGs endanger public health and welfare under the Clean Air Act and was the triggering action that gave EPA the authority to regulate GHG emissions on mobile and stationary sources. Without it, the legal basis for GHG regulation under the Clean Air Act is in serious jeopardy.
This final rule also repealed all GHG emission standards for light-duty, medium-duty, and heavy-duty vehicles and engines. The immediate effect of this action is that engine and vehicle manufacturers will no longer have any future obligations for the measurement, control, and reporting of GHG emissions for any highway engine and vehicle, including model years manufactured prior to this final rule.
Some may forget that the federal government has been regulating fuel efficiency in automobiles for 50 years and this authority is not affected by this latest EPA action. Even absent EPA’s 2009 Endangerment Finding, the federal government will continue to regulate automobile fuel economy, just not through the Clean Air Act. Fuel economy standards are set under the Energy Policy and Conservation Act (EPCA). EPCA was enacted in 1975 in response to the oil crisis and is implemented by the U.S. Department of Transportation.
EPA’s Repeal of the Endangerment Finding – The End of the Beginning?
The final rule to rescind the 2009 Endangerment Finding is expected to face litigation, so the long-term regulatory consequences are highly uncertain. Because the final rule is expected to be challenged, regulated stationary sources should continue to monitor litigation developments and assess potential impacts to operations and planning. One specific item worth tracking is whether the D.C. Circuit will stay the repeal during litigation because that may slow EPA down from taking additional measures to undo other GHG regulations while the litigation is pending.
In regard to the expected litigation, many of the “experts” that are cited in mainstream news articles consistently take the position as in a recent CBS News article:
“Legal experts note the 2009 endangerment finding is supported by long-standing science and years of federal court rulings. The Supreme Court has affirmed that greenhouse gases are air pollutants subject to Clean Air Act regulation.”
The outcome of any litigation on complicated environmental issues is uncertain, and these experts may ultimately be proven correct. But they appear to be missing some relevant facts that could undermine their assumptions. First, the 2009 Endangerment Finding was never reviewed by the Supreme Court. So, there are not any previous Supreme Court decisions on that subject. Second, while many of EPA’s GHG rules have survived previous court challenges, not all of them have prevailed. Notably, the original Clean Power Plan was invalidated in West Virginia v. EPA (2022). EPA’s GHG Tailoring Rule was mostly invalidated in Utility Air Regulatory Group v. EPA (2014), and, finally, EPA’s administrative authority was significantly impacted by Supreme Court cases in the cases West Virginia and in Loper Bright Enterprises v. Raimondo (2024). In West Virginia, the Supreme Court held that EPA may not adopt expansive, system wide regulatory programs absent a clear delegation of authority from Congress. In Loper Bright Enterprises, the Supreme Court constrained EPA’s ability to rely on broad interpretations of statutory authority. Each of these cases would seem to be relevant to situations where EPA attempts to implement broad or novel regulatory programs that extend beyond clearly delegated statutory authority, which is the case for all the GHG regulatory programs EPA has implemented since the 2009 Endangerment Finding.
Regulation of Greenhouse Gases under the Clean Air Act
Last year, Trinity addressed the proposed rule to rescind the 2009 Endangerment Finding in an article. Another Trinity article looked back at the history of GHG regulation under the Clean Air Act and how the 2009 Endangerment Finding led to the regulation of GHGs at stationary sources. Now that seven months have passed since the original proposal to rescind the 2009 Endangerment Finding, it is worth looking at what else has transpired with respect to GHG regulation at stationary sources and what we need to be on the lookout for in the near future.
Even though the 2009 Endangerment Finding has been rescinded, the existing greenhouse-gas regulatory system for stationary sources does not immediately disappear. However, one could look at it as a game of dominoes and once the first domino (2009 Endangerment Finding) falls, the fall of the rest may be inevitable.
Several states have GHG stationary source regulations that are independent of the federal government. These regulations are not impacted by EPA’s final action to rescind the 2009 Endangerment Finding and regulated sources must continue to comply with these regulations even if EPA’s action survives legal challenge. However, Georgia, like most states, does not have any GHG stationary source regulations that are independent of the federal government. So, in Georgia, we simply need to track what happens at the federal level.
Here are the significant GHG regulations for stationary sources to monitor:
- Clean Power Plan 2.0. This refers to EPA’s GHG standards for new and existing fossil-fuel-fired power plants issued under Clean Air Act §111 finalized on April 25, 2024. On June 17, 2025, EPA issued a proposed rule to repeal all GHG emissions standards for fossil fuel-fired power plants, specifically 40 CFR 60 Subparts TTTT, TTTTa and UUUUb. The comment period ended on August 7, 2025, but there have been no updates regarding this final rule at the time of writing of this article.
- Mandatory GHG Reporting Program. This refers to EPA’s rule in 40 CFR 98 that requires large emitters and fuel or industrial gas suppliers to calculate and submit annual GHG data to EPA if emissions exceed 25,000 metric tons CO2-equivalent per year across listed source categories. On September 16, 2025, EPA issued a proposed rule to remove program obligations for most source categories. If finalized as proposed, no industries would need to submit reports with 2025 data. EPA is also proposing to extend the normal March 31, 2026, reporting deadline until June 10, 2026. This extension, if finalized before March 31, 2026, would allow EPA time to issue a final rule prior to the regulatory deadline for reporting year 2025.
- Prevention of Significant Deterioration (PSD) Regulations. Under the PSD program, GHGs are regulated as a “regulated New Source Review (NSR) pollutant.” GHG regulation is not triggered solely by GHG emissions; a source must first subject to PSD for another regulated pollutant and then GHGs are subject to PSD if CO2-equivalent emissions exceed 75,000 tons per year. If the repeal of the 2009 Endangerment Finding survives, GHGs may no longer be a “regulated NSR pollutant” and PSD may no longer be applicable to GHGs. Another complication is the status of the New Source Performance Standard (NSPS) regulations for GHGs and if they provide an independent mechanism for GHGs being subject to regulation. Expect significant permitting confusion under this scenario until EPA and state guidance provide clarity.
What Should Stationary Sources Subject to GHG Regulations Do?
This GHG regulatory uncertainty is far from over. In the near term, regulated sources should track the applicability of the March 31, 2026, deadline for the Mandatory GHG Reporting Program. In the longer term, as these issues continue to evolve, affected permittees will need to track both the EPA regulatory decisions as well as litigation developments to ensure they are prepared to adapt to this rapidly changing regulatory environment.
Air permittees looking for assistance with upcoming permit applications or guidance in navigating these fast moving changes, please contact Katherine Katsourides, Southeast Manager. Learn more about Trinity’s services on the new Georgia state webpage.
