Many speculated on just how much Loper Bright Enterprises v. Raimondo (Loper Bright) would affect agency rulemaking challenges. Well, the D.C. Circuit is showing that that effect may be milder than expected. Huntsman Petrochemical, the American Chemistry Council, and the Louisiana Chemical Association (Petitioners) tested how a post-Chevron world could look under judicial review of agency decisions. In a unanimous decision on August 13, 2024, the court upheld EPA’s tighter emission standards of Miscellaneous Organic Chemical Manufacturing facilities under the Administrative Procedures Act (APA).

Miscellaneous Organic Chemical Manufacturing Facilities manufacture a variety of products such as antifreeze, plastics, adhesives, and other common products found in everyday life. Under section 7412 of the Clean Air Act, EPA is required to tighten emissions standards if it determines that certain emissions pose an unacceptable risk to public health. After finding that living next to these facilities could increase an individual’s risk of cancer from exposure to ethylene oxide that is more than four times what EPA generally considers acceptable risk – EPA tightened emission standards. Challenges were filed.

Petitioners challenged EPA’s risk conclusions, citing deficiencies in EPA’s data selection and modeling choices. During the notice and comment period, Petitioners offered their preferred model and other studies to consider. Notably, Texas’s Environmental Agency’s own model estimated a cancer risk about 3,000 times lower than EPA’s model. EPA ultimately rejected Petitioner’s model and finalized the rule.

In upholding the regulations, the court didn’t even cite Loper Bright or Chevron. The court turned to the APA’s arbitrary and capricious standard and asked whether the agency’s action is reasonable and could be reasonably explained. The answer to those questions was a unanimous, yes, and more importantly, the court afforded the agency an “extreme degree of deference.” Referencing past case law, extreme deference is appropriate during EPA’s evaluation of scientific data within its area of expertise. The court observed that they are no statisticians and if EPA hasn’t departed from a rational course, then judges cannot conclude their model was arbitrary and capricious. The court referenced this extreme degree of deference three separate times and didn’t cite Loper Bright or Chevron once. When asked how a post-Chevron world affects agency rulemaking challenges, the answer may now be case specific as judges may still be inclined to defer, extreme or not, recognizing their own scientific short-comings relative to agency experts.