On June 25, 2018, the NAM moved to intervene in this permitting reform case involving a streamlined and commonsense approach to Clean Air Act permits for facility expansions or modifications. Environmental groups originally sued to challenge a guidance document from the U.S. Environmental Protection Agency (EPA) that simplifies CAA permitting under the New Source Review program for facilities that expand or modify their operations--the Project Emissions Accounting rule. The NAM's motion to intervene asked the court to allow the NAM to become a co-defendant in the case alongside the EPA to help defend this sensible policy. On July 13, 2018, the court held the case in abeyance pending the completion of an EPA rulemaking to implement the terms of the guidance document. The abeyance endured for 7 years, through the Biden administration's 2024 proposal to undo the rule before its finalization. In July 2025, the Trump 2.0 EPA withdrew this proposal, and environmental groups sued to challenge the withdrawal.
The D.C. Circuit subsequently consolidated each of the challenges regarding the PEA rule and reactivated the case in the fall of 2025.
The NAM and its fellow industry intervenors followed our primary brief in defense of the rule on February 5, 2026, arguing that the rule strikes the proper balance of promoting both "national air resources and the productive capacity of the population." The rule ensures that when major projects that significantly increase actual emissions are undertaken at industrial facilities, emission controls can be designed into the project at that time. It sensibly requires that all effects of a project--emissions increases and decreases--must be considered.
Happily, following oral argument, on July 28, 2026, the court ruled unanimously in our favor, writing that the rule "brings the two steps [of the NSR analysis] into greater harmony by discarding a framework that required a gross calculation at Step One and a net calculation at Step Two in favor of a framework that requires a net calculation at both steps." This decision should make it much harder for a future EPA to take a different or more burdensome approach to NSR review.