Fifth Circuit Review – Reviewed: A Grain of Procedure for the EPA
Another EPA rule met its demise in the Fifth Circuit this week. The case is Texas Corn Producers v. EPA—which presented a very technical dispute over how the government calculates vehicle fuel efficiency, but the substance of the rule did not play that big a role in the decision. This decision focused almost exclusively on the procedure.
Let’s back up.
For nearly 50 years, federal law has required carmakers to make vehicles more fuel efficient. These rules are enforced through Corporate Average Fuel Economy (CAFE) standards, which are calculated in part through controlled fuel economy testing. Because the gasoline used in these tests has changed—most notably shifting from pure gasoline to ethanol-blended fuels (like E10)—the EPA adjusts test results using something called the “R factor.” Think of it as a correction coefficient to ensure apples-to-apples comparisons over time.
In 2020, the EPA proposed a new version of that adjustment, called the “Ra factor.” After conducting internal tests on 11 vehicles from model years 2013–2016, the agency proposed setting the Ra factor at 0.81. Industry groups cried foul.
Their concern was that a lower Ra factor would artificially increase fuel economy standards. That increase would force automakers to build more efficient vehicles, which would in turn reduce gasoline consumption. Corn and sorghum producers, who supply ethanol, and fuel trade groups saw a direct hit to their bottom lines, so they submitted comments criticizing the EPA’s math, methodology, and assumptions. They warned that the agency’s data sample was far too small, relied on outdated vehicle models, and ignored larger, more representative datasets already available.
The EPA finalized its rule in 2024 despite their concerns. It explained in two paragraphs why it thought those concerns were invalid. The corn producers thought that explanation was insufficient, so it challenged the agency’s decision under the Administrative Procedures Act (“APA”).
In a sweeping opinion, the Fifth Circuit sided with the petitioners and vacated the Ra factor. Writing for the court, Judge Smith explained that the APA requires agencies to consider all relevant data, respond to significant public comments, and explain why they chose one course of action over another. The two paragraphs provided by the EPA had done none of that, the court concluded.
Much of the decision was about standing. Judge Smith spent pages explaining why the economic harms feared by fuel and agriculture groups weren’t speculative. In fact, the court emphasized, reducing gasoline use was the entire point of the CAFE program. If the EPA inflated the standards through a faulty Ra factor, harm was not just likely—it was inevitable.
In the end, Texas Corn Producers v. EPA is about more than fuel economy. It will likely increase the burden on agencies to provide specific, well-supported comments during the rulemaking process.
Damonta D. Morgan is an attorney with Forman Watkins & Krutz, LLP in Jackson, MS.