Ninth Circuit finds EPA’s approval of State Implementation Plan dealing with ozone in San Joaquin Valley was arbitrary and capricious by relying on old data

Sierra Club v. U.S. E.P.A.
(9th Cir. 2012)
Jan. 20, 2012
2012 DJDAR 844
10-71457

Environmental organizations challenged the federal EPA’s approval in 2010 of California’s proposed 2004 state implementation plan (SIP) for the San Joaquin Valley’s nonattainment area for the one-hour ozone National Ambient Air Quality Standard, where the degree of danger to human health from ozone was considered extreme.

While California can regulate stationary sources of emissions, it must get first get EPA approval before setting standards from mobile sources such as vehicles.

The Ninth Circuit Court of Appeal had original jurisdiction under the Clean Air Act (CAA) to hear the case. The Court agreed with plaintiffs that the EPA had acted arbitrarily and capriciously by approving the SIP knowing that the emissions inventory upon which it relied were outdated and inaccurate. The CAA requires nonattainment plans to “include a comprehensive, accurate and current inventory of actual emissions from all sources of relevant pollutant or pollutants in such area.” The state based the 2004 SIP on data from 2002.┬áBy the time the EPA considered the SIP in 2010, new data from a newer computer modeling tool had become available. Rather than use this data, the EPA relied upon an internal guidance memo that suggested it could use data that was current as of the time the SIP was submitted to the EPA. The Court found the memo (Seitz memo) even questioned reliance on greatly outdated data after much time had elapse.

Another Circuit Court of Appeal had previously approved EPA reliance on the Seitz memo where the EPA ignored new data that became available one year before EPA approval of a SIP. The reasoning was that an agency might not be able to work efficiently if it were forced to stop everything and consider every new piece of information. But here, the EPA had new data for three years before approval. The Court held the EPA could not ignore evidence that showed a nonattainment plan was inadequate while relying on insignificantly outdated data.

The EPA also argued it could ignore the 2007 8-hour ozone emissions data because they were not relevant to the 2004 1-hour data. The Court was unpersuaded and noted the 2007 data showed significantly different and higher NOx emissions which can lead to harmful ground-level ozone. That underscored that the 2004 SIP may have been significantly flawed.

Finally, the Court concluded that EPA’s own failure to address substantively the disparities between the 2007 and 2004 emissions inventories prevented the Court from determining if there were any merit to EPA’s argument. The EPA’s failure to explain its choice of certain data over other data made its approval of the SIP arbitrary and capricious.

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