TELEPHONE: (760) 4K2-4606 EL CENTRO,CA 92243-2850 150 SOUTH NINTH STREET FAX: (760, 353-9904

March 3, 2010

Jared Blumenfeld Regional Administrator U.S. Environmental Protection Agency (EPA), Region IX 75 Hawthorne Street San Francisco, CA 94105-39001

SUBJECT: Response to the December 22, 2009 letterfrom the U.S. Envi"onmental Protection Agency regarding the California Air Resources Board's Imperial County's Exceptional Events Request

Dear Mr. Blumenfeld:
The California Air Resources Board (ARB) submitted documentation ofthree exceptional events (September 2,2006, April 12, 2007 and June 5,2007) in May 2009 to the U.:3. Environmental Protection Agency (EPA). In a December 22, 2009 letter (EPA Events Letter) from Laura Yoshii, Acting Regional Director of EPA Region IX to James Goldstene, ARB Executive Officer, EPA refused to concurwith ARB's requestto flag these exceedences as**exc~ptional** events. We have reviewed the EPA Events Letter and are greatly troubled by EPA's nterpretation ofthe Exceptional Event Rule (EER) and the technical information availablefor the:;e days, both of which we believe are plainly inconsistent with existing regulations and guidarlce on exceptional event determinations. The implications of EPA's refusal to flag these data, if it is allowed to stand, arefar-reaching and could adversely impact airquality planning and pDlicy in Imperial County and throughoutthe southwestern United States. Our concerns and objections are presented in more detail in Attachment

### A. The key issues are summarized briefly below:

• We do not agree with EPA's interpretation ofthe Exceptional Event Rule (EER) orthe conclusion thatthe flagged natural events somehow do not merit EP,L\'s concurrence because ofits desireto see certain control measures on anthropogenic sources improved. As discussed herein, EPA's objections that dust controls were insufficient or inadequate on the eventdays is tantamountto a conclusion thatthe E'vents were reasonably controllable or preventable. That conclusion is completel)' unsupported by the available evidence. EPA has provided no evidence to refute the critical conclusion legally required underthe EER

- thatthe exceptional 

### events (Le., the combination ofthe high winds, the unusual levels ofdust entrainmentfrom**nonanthropo~lenic** and anthropogenic sources, and the resulting exceedences atthe Imperial County monitors) were not reasonably controllable or preventable.

• In the EPA Events Letter, EPAtakes the position thatthe requiremen1 for an exceptional eventto be "not reasonably controllable or preventable" inherently implies "a requirementthatthe state demonstratethat anthropogenic sources contributing to the exceedance caused by the event were reasonably controlled." This interpretation ofthe EER appears to be inconsistentwith the language of40 CFR §50.1 U), which defines an "exceptional event" as one caused by a natural event or**non-recurrin~** human activity and which is 

### itself"not reasonably controllable or preventable." Undmthe legaldefinition, it is irrelevantwhat controls are in place on the day ofan otherwise qualifying event ifit can be shown that such controls would not have reduced emissions enough to prevent an exceedance anyway.

• We also disagree with EPA's position thatthe EERjustifies the use of BestAvailable Control Measures (BACM) as the "appropriate

... level ofcontrol in evaluating whether reasonable controls are in place" in determining whether an event 

### ma:1 qualify as exceptional underthe EER. This interpretation is unsupported by the language ofthe EER and inconsistentwith the intent ofthe EER. The purpose ofthe I=ER is to protect states from suffering the consequences of reclassification to a more**sl~rious** designation as a result of"exceptional" events forwhich the normal planning and regulatory process established by the CM is not appropriate. EPA's analysis ofexceptic,nal events should not depend on elements ofthe normal planning process, including the area's particular attainment status. In otherwords, the standardsfor determining an e:cceptional event in a serious nonattainment area should be no differentthan determining one in a moderate area or in an attainment area.

• We also object to EPA's incomplete and misleading characterization clffugitive dust controls in Imperial County. In the EPA Events letter, EPA implies thct dust controls are not adequate because ofconcerns aboutfallowed lands and OHV-related contributions. On the contrary:


## >­ Farm lands produce significantly less emissions, taken as awl10le or on a peracre basis, compared to remote desert lands in the County**dUI~** in partto ICAPCD's adoption of Rule 806, which requires a host ofconservation management practices to prevent, reduce and mitigate PM emissions from agricultural sources.' Rule 806 was adopted in November2005, years before the 2009 PM 10 SIp2 was developed and adopted. That rule was modeled on the San Joaquin Valley Air Pollution Control District's Rule 4550, which was approved by EPA on May 26, 2004.3 EPA makes no mention of Rule 806 when discussing the County's agricultural controls.


## >­ Imperial County has been paving unpaved roads at great eXpE!nSe and despite hard economic times and record unemployment in the County it began meeting its rule commitment starting in 2006. Despite thefactthat EPA has worked with ARB and ICAPCD lorover a decade, including on the development of rules and BACM Technical Analysis beginning in 2004 and analysis ofthe exceptional events beginning in 200E, EPA never raised concerns about OHV-related contributions until afterthe Exceptional Events documents were submitted by ARB in May 2009 and afterthe draft PM 10 SIP was released in July 2009.4 The draft PM 10 SIP was revised to adclress those concerns. In any event, there is no basis for EPA's conclusion that OHV controls

1 See Table 3.1 and Figure III.B.4 ofthe 2009 Imperial County PMlO SIP.
2 Imperial County 2009 PMlO SIP, Final Draft, August 2009
3 69 FR 30035, May26, 2004

4 In addition, EPA did not raise these concernswhile working with ARB and ICAPCD for over ayearand a halfon the Exceptional Events documentation orwhile working with ARB and ICAPCD for overtwoyears on the development of the PMlO SIP, orduring the 30-day public comment period on the Exceptional Events documellts (during which there were NO public comments submitted), or beforethe draft PMlO SIP was released.

-2­somehowwould have prevented any ofthe exceedences attributable tothe exceptional event days.

• EPA has misinterpreted technical information submitted by ARB and ICAPCD, which appears to have led to EPA's erroneous conclusions related to causality. ARB and ICAPCD carefully documented PM transportto show howsuch transp,)rt affected the September 2006Westmorland and Calexico exceedances (see Secticns 2.1.1 and 2.1.2 ofAttachmentA). As discussed further in the attachment, EPA's interlxetation ofthe September2006 exceedences is incorrect, and was not based on a sound technical understanding ofthe events associated with those exceedences.

• EPA's decision making regarding the level ofevidence/documentation necessary to establish causality is not correct and is not consistent with the EER.

).> First, EPA's letter appears to set an impossible and legally unsupported standard for the evidence required to supportthe causality requirement ,)f an exceptional event determination (Le., to show a clear causal relationship bHtween the exceedances and a qualifying event). EPA demands ever more detail about the exact sources ofdust and wind transport as part ofthe exceptj,)nal events showing, yet has not clearly specified what level ofdetail (if an'() would be sufficient to convince EPAthatthe exceptional events beyond the District's reasonable control were responsible for the measured exceedances.

).> Also, ratherthan considering the cumulative weight ofthe evidence showing that unpreventable exceptional events caused the exceedances at issue, EPA has chosen to evaluate each piece of supporting data separately a1d conclude that each separate piece alonedoes not support a causal relationship for the event. EPA has not considered the implications ofthis novel and troul)ling position regarding causality on SIP determinations and other regulato!) processes.
).> For reasons that are detailed in AttachmentA, we believe that the level ofdata, analyses, and documentationthat would be required to meet EPA's apparent proofthresholds (Le., to satisfy the causality and "but-for" requ rements ofthe EER) here would exceed even the requirements for SIP planning itself. That is clearly inconsistentwith the intent ofthe EER. The EER requires the weight of evidence to be taken as awhole, and rejecting flagged data is tantamountto a determinationthat "the exceedances were caused by recurrin£ anthropogenic sources" (see 72 FR 13574). EPA cannot reject ARB's documentation ofthe exceptional events without producing such proofsufficient to overcomethe great weight ofthe evidence to the contrary.
Based on the weight ofavailable evidence and the established EER requirements and guidance, the events described in the ARB submittal clearly were exceptional eventsthat themselves were not reasonably controllable or preventable, and which direc11y led to the measured exceedances. EPA has not demonstrated (and cannot demonstra':e) that these exceedances were caused by anthropogenic sources and thus somehow apl=ropriate for consideration in normal SIP planning.
Thus, we strongly urge EPAto reconsider its decision and concurwith ARB's request to flag these exceedences as exceptional events, consistent with the intent and language ofthe EER. Failure to reverse this decision will not only result in a decision unsupported by the law orthe

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### data, but also would create troubling precedentfor both future exceptional eve'nt documentations and related SIP planning in the southwestern United States. Both results would be unacceptable, and could subject EPAto a challenge or other action. 

# Sl:Qh

Brad pOiriez 

## l

# s.n
Air Pollution Control Officer, ICAPCD

cc: ICAPCD Board of Directors Gina McCarthy, Assistant AdministratorforAirAnd Radiation, EPA Headquarters Deborah Jordan, Air Division Director, EPA Region IX James Goldstene, Executive Officer, ARB

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