Bahr et al v. McCarthy

On July 29, 2014 the Center filed a Petition for Review challenging EPA's approval of a revision to the Arizona State Implementation Plan under the Clean Air Act (CAA).  Because the Phoenix metropolitan nonattainment area failed to attain the National Ambient Air Quality Standard (NAAQS) for PM-10 by December 31, 2006, pursuant to section 189(d) of the CAA the state was required to submit “plan revisions which provide for attainment of the PM-10 air quality standard and, from the date of such submission until attainment, for an annual reduction in PM-10 or PM-10 precursor emissions within the area of not less than 5 percent of the amount of such emissions as reported in the most recent inventory prepared for such area." Arizona initially submitted a 5% plan in 2007, but withdrew it in January 2011 when EPA proposed disapproving it.  The state then submitted a substitute plan in May 2012, which EPA has now approved.  

Although Petitioners have raised several issues with the Plan, the most significant issue is the state’s reliance upon the exceptional events rule to demonstrate “attainment.”  According to the monitors, the area continues to violate the NAAQS, particularly during the monsoon season.  Consequently, the state has sought to have those violations excluded as “exceptional events.”  An exceptional event is defined as “an event that affects air quality; is not reasonably controllable or preventable; is an event caused by human activity that is unlikely to recur at a particular location or a natural event.” In the case of the 5% plan, the state can only demonstrate “attainment” if 127 exceedances that occurred over 25 days are excluded from the data as “exceptional events.”  If these exceedances were not excluded, 14 of the 16 monitoring sites that reported exceedances would be violating the standard by a significant measure. We believe EPA's concurrence in excluding these data is an abuse of discretion.

We filed our opening brief on October 17, 2014.  Our Reply Brief was filed in February 2015.  The Ninth Circuit heard oral argument on the Petition on June 17, 2016.  You can watch the oral argument here.  

On September 12, 2016, the Ninth Circuit published its decision granting our petition in part and denying it in part.  Although the court rejected our argument regarding the exceptional events, it did agree with a separate argument that we advanced that EPA's practice of allowing states to use already implemented control measures to satisfy the Act's requirement of "contingency measures" to be implemented when the state failed to meet an applicable deadline or milestone was contrary to the plain language of the statute.  EPA and the state have filed a Petition for Reconsideration and Consideration en Banc of that portion of the court's ruling.