Page:Alliance for Hippocratic Medicine v. U.S. Food and Drug Administration (5th Cir. Apr. 12, 2023).pdf/28

 In a series of rulemakings between 2002 and 2006, EPA substantially weakened the requirement that sources maintain and follow an SSM plan in order to benefit from the SSM exemption. It removed the requirement that a source’s Title V permit incorporate its SSM plan; it stopped making SSM plans publicly available; and it ultimately retracted the requirement that sources implement their SSM plans during SSM periods. Id. at 1023.

The Sierra Club filed suit in 2007. But the Sierra Club did not challenge the changes to the SSM plan requirements that EPA had adopted in its 2002, 2003, and 2006 rulemakings. Instead, it challenged the legality of the SSM exemption itself. Id. at 1024. EPA had adopted that exception in 1994 and had not considered rescinding it in any of its rulemakings during the 2000s. Rather, those rulemakings had treated the SSM exemption as a given—in fact, they had strengthened it by weakening the SSM plan requirements. See id. at 1022–23.

The D.C. Circuit nonetheless held that the Sierra Club’s challenge to the SSM exemption was timely. Even though EPA had not expressly reopened its decision to create a SSM exemption, it had constructively reopened that decision “by stripping out virtually all of the SSM plan requirements that it created to contain that exemption.” Id. at 1025 (quotation omitted). Because EPA had allegedly abandoned these “necessary safeguards” limiting the SSM exemption, its rulemakings had “changed the calculus for petitioners in seeking judicial review and thereby constructively reopened consideration of the exemption.” Id. at 1025–26 (quotation omitted).

Sierra Club thus establishes that an agency can constructively reopen a decision if it removes essential safeguards that had previously limited or contained the impact of that decision. In making this determination, the D.C. Circuit looks to the extent to which the agency has “alter[ed] th[e] regulatory