744 F.3d 1334
D.C. Cir.2013Background
- EPA revised the primary and secondary ozone NAAQS in 2008, lowering the 8‑hour primary standard from an effective 0.084 ppm (commonly cited 0.08) to 0.075 ppm and set the secondary standard identical to the new primary standard.
- EPA relied on new clinical (controlled human exposure), epidemiological, and risk/exposure assessment evidence developed since the 1997 review, and on CASAC advice; CASAC unanimously recommended a primary range of 0.060–0.070 ppm and urged a seasonal cumulative form for the secondary standard.
- Multiple petitioners challenged the 2008 rule: states and environmental/public‑health groups argued the standards were too lax; Mississippi and industry groups argued the standards were overly stringent and attacked EPA’s science and procedures.
- The D.C. Circuit reviews NAAQS under an arbitrary‑and‑capricious standard with substantial deference to EPA’s scientific and policy judgments, but requires EPA to explain departures from CASAC and to specify the level “requisite” to protect public welfare for secondary NAAQS.
- The court denied challenges to the primary standard (0.075 ppm), concluding EPA reasonably weighed the evidence, built an adequate margin of safety, and adequately explained departures from CASAC given CASAC’s imprecision about the basis of its recommendation.
- The court granted petitioners’ challenge to the secondary standard and remanded because EPA failed to specify what level of air quality is ‘‘requisite to protect the public welfare’’ and relied improperly on a comparison to a single seasonal level (21 ppm‑hours) without determining or explaining that level as requisite.
Issues
| Issue | Plaintiff's Argument | Defendant's Argument | Held |
|---|---|---|---|
| Whether EPA reasonably revised the primary NAAQS to 0.075 ppm (Mississippi/industry challenge) | EPA lacked sufficient new evidence and misused studies; must compare 2008 and 1997 risk assessments; violated Information Quality Act and Clean Air Act procedures | EPA reasonably relied on new clinical, epidemiological, and risk evidence; not bound to prior NAAQS; IQA and peer‑review claims do not nullify rational action | Denied. Court held EPA rationally explained the record, was not bound to 1997 decisions, and acted within its discretion. |
| Whether EPA’s primary NAAQS is too lax (states, NGOs) — adequacy of considering evidence below 0.075 ppm | EPA ignored or undervalued controlled human exposure, epidemiology, and risk assessments showing adverse effects below 0.075 ppm; margin of safety inadequate | EPA considered the full record, reasonably found uncertainty below 0.075 ppm, and balanced uncertainty against policy and margin‑of‑safety considerations | Denied. Court held EPA reasonably weighed evidence and built an adequate margin of safety; deference to EPA’s policy judgment appropriate. |
| Whether EPA adequately explained departure from CASAC (primary standard) | EPA failed to justify departing from CASAC’s unanimous 0.060–0.070 ppm recommendation | EPA explained scientific uncertainties at lower levels and treated CASAC’s recommendation as a mix of science and policy; CASAC did not specify whether 0.070 ppm rested on definitive scientific findings | Denied. Court held EPA’s explanation adequate because CASAC did not clearly ground its range in a definitive scientific finding that EPA had to rebut. |
| Whether the secondary NAAQS (welfare/vegetation) lawfully may be identical to the primary standard | EPA unlawfully adopted identical secondary standard without specifying a level "requisite" to protect welfare; failed to follow American Farm Bureau guidance | EPA compared revised primary to seasonal alternatives and found significant overlap; argued it identified target protection via focus on 21 ppm‑hours | Granted in part. Court remanded the secondary NAAQS: EPA failed to specify the requisite welfare protection level and improperly relied on a single comparison to 21 ppm‑hours without showing that level was requisite. |
Key Cases Cited
- American Trucking Ass’ns v. EPA, 283 F.3d 355 (D.C. Cir. 2002) (describing NAAQS review framework and deference to EPA)
- Whitman v. American Trucking Ass’ns, 531 U.S. 457 (2001) (statutory meaning of "requisite" and limits on cost consideration)
- Lead Indus. Ass’n v. EPA, 647 F.2d 1130 (D.C. Cir. 1980) (deference to agency margin‑of‑safety policy judgments)
- Motor Vehicle Mfrs. Ass’n v. State Farm, 463 U.S. 29 (1983) (arbitrary and capricious review standard)
- American Farm Bureau Fed’n v. EPA, 559 F.3d 512 (D.C. Cir. 2009) (agency must determine and explain what level is "requisite" for secondary welfare NAAQS)
- Ethyl Corp. v. EPA, 541 F.2d 1 (D.C. Cir. 1976) (weight‑of‑evidence approach in agency decisionmaking)
- Coalition for Responsible Regulation, Inc. v. EPA, 684 F.3d 102 (D.C. Cir. 2012) (substantial‑evidence review of EPA scientific judgments)