Sierra Club v. Environmental Protection Agency, 705 F.3d 458

EPA issued PM2.5 PSD rule establishing SILs and SMC; Sierra Club petitions for review.
EPA conceded SILs flawed and sought vacatur/remand of SIL provisions but kept some.
Sierra Club challenges EPA authority to promulgate SILs; UARG urges upholding or partial remand.
Court accepts EPA concession, vacates/remands SIL provisions and holds EPA exceeded authority on SMC; petition granted as to SMC.
Court emphasizes §165(e)(2) preconstruction monitoring rigidity and rejects EPA de minimis authority to exempt monitoring.

Issue	Plaintiff's Argument	Defendant's Argument	Held
Authority to promulgate PM2.5 SILs.	Sierra Club argued EPA lacked de minimis authority.	EPA asserted some SIL provisions could be lawful but needed remand.	SIL provisions vacated/remanded; §51.165(b)(2) retained.
Authority to promulgate PM2.5 SMCs.	SMC exemptions improperly bypass preconstruction monitoring.	EPA had de minimis authority to exempt monitoring.	SMC provisions vacated; EPA exceeded authority.
Timeliness of challenge to SMC under §307(b)(1).	Sierra Club timely challenged new PM2.5 rules.	Challenge barred by §307(b)(1) due to prior actions.	Challenge not time-barred; merits considered.

Alabama Power Co. v. Costle, 636 F.2d 323 (D.C. Cir. 1980) (de minimis authority; statutory mandates must be honored)
Ohio v. EPA, 838 F.2d 1325 (D.C. Cir. 1988) (renewed challenge may be allowed after new promulgation)
Public Citizen v. Young, 831 F.2d 1108 (D.C. Cir. 1987) (limits on agency's implied authority; rigidity of statute)
Fertilizer Institute v. EPA, 935 F.2d 1303 (D.C. Cir. 1991) (equitable leave-in-place versus vacatur for procedural defects)
Medical Waste Institute v. EPA, 645 F.3d 420 (D.C. Cir. 2011) (timeliness of challenges when new regulation creates renewed scrutiny)
Energy Recovery Council v. EPA, 645 F.3d 420 (D.C. Cir. 2011) (same decision context on review timing)