The Ninth Circuit Court of Appeals has ordered EPA to re-examine a California plan for meeting air quality standards for ozone under the Clean Air Act (CAA). Ass’n of Irritated Residents v. EPA, No. 09-71383 (9th Cir. 2/2/11). Petitioners challenged EPA’s partial approval of California’s State Implementation Plan (SIP), arguing that the agency (i) failed to require the state to submit a plan that meets the federal ozone pollution standard, (ii) unlawfully approved an unenforceable commitment to adopt pesticide regulations, and (iii) approved a plan that did not include requirements to reduce emissions from increased vehicular traffic in Los Angeles.

Agreeing with petitioners, the court ruled that EPA’s partial approval of the state SIP was “arbitrary and capricious” and remanded the matter to the agency. Specifically, the court held that EPA knew that the state plan was inadequate in part because vehicular traffic had increased, yet failed to compel the state to update its plan to meet the standards. The court also ruled that EPA should have required the state to submit transportation-control measures, such as improved public transit, high-occupancy lanes and programs for bicycle storage facilities, to offset the expected 30 percent increase in vehicular traffic. The court also said that EPA failed to force the state to meet the CAA’s pesticide standards.