## Facts

- EPA issued a final rule regulating emissions from snowmobiles and other nonroad engines under Clean Air Act (CAA) § 213.
- The rule set standards for snowmobile emissions of carbon monoxide (CO), hydrocarbons (HC), and oxides of nitrogen (NOx).
- For CO, EPA proceeded under CAA § 213(a)(3), which requires standards reflecting the “greatest degree of emission reduction achievable,” considering cost and related factors, after a triggering contribution finding.
- For HC and NOx, EPA relied on CAA § 213(a)(4), which authorizes EPA to set standards it “deems appropriate” for certain emissions based on technology and cost considerations.
- EPA projected compliance would require substantial use of advanced engine technologies (including direct-injection two-stroke and four-stroke designs) and estimated that by 2012 about 70% of new snowmobiles would use such technologies; EPA concluded broader adoption by 2012 was not feasible due to manufacturer resource constraints and required investment across diverse models.
- Environmental organizations petitioned for review, arguing the standards were unlawfully weak under § 213’s technology-forcing mandate.
- The snowmobile manufacturers’ association petitioned for review, arguing EPA exceeded its authority and acted unreasonably in setting the standards.

## Issues

1. Whether EPA lawfully applied CAA § 213(a)(3) to set CO standards reflecting the “greatest degree of emission reduction achievable,” considering technology availability, cost, and lead time.
2. Whether EPA permissibly relied on CAA § 213(a)(4) to regulate HC and NOx from snowmobiles, given § 213(a)(4)’s reference to “emissions not referred to in” § 213(a)(2).
3. Whether EPA’s technology, cost, and timing determinations were adequately explained and supported under arbitrary-and-capricious review.
4. Whether industry petitioners showed EPA lacked statutory authority or imposed standards that were unlawful or irrational.

## Decision

- The court denied the consolidated petitions for review and largely upheld EPA’s snowmobile emissions standards.
- The court rejected environmental petitioners’ claim that § 213(a)(3) required stricter standards than EPA adopted, holding EPA reasonably concluded more stringent requirements were not achievable within the relevant timeframe given record-supported constraints.
- The court upheld EPA’s use of § 213(a)(4) for HC and NOx as a permissible interpretation of the statutory scheme.
- The court rejected the manufacturers’ challenges, holding EPA acted within its statutory authority and provided a reasoned basis for its feasibility and cost judgments.
- Applying deferential review, the court concluded EPA examined the relevant data and provided a satisfactory explanation for its choices.

## Legal Principles

- Under CAA § 213(a)(3), “greatest degree of emission reduction achievable” is tied to technology that will be available within the compliance period and permits consideration of cost, lead time, safety, and energy factors; it does not require a purely theoretical maximum.
- EPA may project technology penetration and decline to require full adoption by a given deadline when the agency reasonably explains feasibility limits grounded in engineering, investment, and product-line constraints.
- EPA’s interpretation of CAA § 213(a)(4) may receive Chevron deference where the statutory text and structure allow a permissible reading that authorizes regulation of additional pollutants based on findings distinct from the § 213(a)(2) trigger.
- Under arbitrary-and-capricious review, courts sustain emissions standards when the agency evaluates relevant technical and economic considerations and articulates a rational connection between the record and the standards selected.
- A regulated industry challenge fails absent a showing that EPA’s statutory interpretation is unlawful or that the agency’s technical and cost determinations lack a rational basis.

## Conclusion

The D.C. Circuit upheld EPA’s snowmobile emissions rule, holding that EPA reasonably interpreted CAA § 213 and adequately supported its technology-forcing standards with record-based feasibility and cost explanations, warranting deference under Chevron and arbitrary-and-capricious review.


Bluewater Network v. EPA, 370 F.3d 1 (D.C. Cir. 2004)