21 F.4th 815
D.C. Cir.2021Background
- EPA promulgated the 2018 Implementation Rule implementing the 2015 ozone NAAQS; petitioners challenged four provisions of that Rule.
- Key statutory framework: Clean Air Act Subpart 2 sets classification, offset ratios, milestone (reasonable further progress) requirements measured from a baseline year, triennial emissions inventories, and contingency-measure rules for ozone and its precursors (VOCs and NOx).
- The four challenged provisions: (1) interprecursor trading for offsets (VOC ↔ NOx), (2) an implementation‑based method (percent‑implementation) to show milestone compliance instead of actual emissions data, (3) allowing two alternative baseline years for reasonable further progress, and (4) permitting already‑implemented measures to count as contingency measures.
- Procedural posture: consolidated petitions for review; earlier challenges to related 2015 Rule issues were largely resolved in South Coast II, but the interprecursor trading issue was left unresolved and incorporated into the 2018 Rule.
- Decision: the D.C. Circuit vacated three provisions (interprecursor trading; implementation‑based milestone demonstrations; use of already‑implemented contingency measures) and upheld the provision allowing states to choose between two alternative baseline years.
Issues
| Issue | Plaintiff's Argument | Defendant's Argument | Held |
|---|---|---|---|
| Interprecursor trading for offsets (VOC ↔ NOx) | Statute requires offsets in the same pollutant ("such air pollutant" = VOC or NOx); interprecursor trading violates plain text | EPA says general definition of "air pollutant" and §7602(g) allow treating ozone (and its precursors interchangeably) and thus permit trading | Vacated: Court found "such air pollutant" unambiguously refers to the specified precursor (VOCs/NOx), prohibiting interprecursor trading |
| Milestone compliance demonstration: implementation‑based method | Implementation method lets states avoid showing actual emissions reductions; statute requires reductions measured from "actual" baseline emissions | EPA argues §7511a(g)(1) gives rulemaking discretion to specify form/manner; practical timing and data‑generation burdens justify implementation option | Vacated: Court held statutory text (baseline = actual emissions; credits only for actually occurred reductions) makes implementation‑based method unreasonable |
| Alternative baseline years for reasonable further progress | (Petitioners) EPA lacks statutory basis to let states choose between two baseline year options | EPA ties default year to triennial inventory cycle and alternative to designation year; both grounded in statute and practical realities | Upheld: Court found both options reasonably grounded in statutory text and permissible for EPA to offer a choice |
| Contingency measures: allowing already‑implemented measures | Already‑implemented measures cannot serve as contingency measures because statute requires measures "to be undertaken if" and "to take effect upon" failure | EPA contends Congress was silent and courts have split; other circuits have upheld EPA in some contexts | Vacated: Court held statutory language is unambiguous—contingency measures must be prospective and not already in effect |
Key Cases Cited
- Chevron U.S.A., Inc. v. Natural Resources Defense Council, Inc., 467 U.S. 837 (1984) (agency deference two‑step framework)
- Whitman v. American Trucking Ass'ns, Inc., 531 U.S. 457 (2001) (Subpart 2 constrains EPA discretion)
- Motor Vehicle Mfrs. Ass'n v. State Farm Mut. Auto. Ins. Co., 463 U.S. 29 (1983) (agency must provide reasoned explanation for rulemaking)
- South Coast Air Quality Mgmt. Dist. v. EPA, 472 F.3d 882 (D.C. Cir. 2006) (Subpart 2 and ozone precursor regulation context)
- South Coast Air Quality Mgmt. Dist. v. EPA, 882 F.3d 1138 (D.C. Cir. 2018) (prior challenge to 2015 implementation rule)
- Natural Resources Defense Council v. EPA, 777 F.3d 456 (D.C. Cir. 2014) (NAAQS implementation framework)
- Clean Air Council v. Pruitt, 862 F.3d 1 (D.C. Cir. 2017) (interpretation of "such air pollutant")
- Bahr v. EPA, 836 F.3d 1218 (9th Cir. 2016) (contingency measures must be prospective)
- Louisiana Envtl. Action Network v. EPA, 382 F.3d 575 (5th Cir. 2004) (upholding EPA interpretation on contingency measures in specific SIP)
- Culbertson v. Berryhill, 139 S. Ct. 517 (2019) (meaning of adjectival "such")