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 letter from 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 of three 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 concur with ARB's request to flag these exceedences as exc~ptional events. 

We have reviewed the EPA Events Letter and are greatly troubled by EPA's nterpretation of the 

Exceptional Event Rule (EER) and the technical information available for 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, are far-reaching and could adversely impact air quality planning and pDlicy in Imperial 

County and throughout the 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 of the Exceptional Event Rule (EER) or the 

conclusion that the flagged natural events somehow do not merit EP,L\'s concurrence 

because of its desire to see certain control measures on anthropogenic sources 

improved. As discussed herein, EPA's objections that dust controls were insufficient or 

inadequate on the event days is tantamount to a conclusion that the 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 under the EER - that the exceptional events (Le., the combination of the 

high winds, the unusual levels of dust entrainment from nonanthropo~lenic and 

anthropogenic sources, and the resulting exceedences at the Imperial County monitors) 

were not reasonably controllable or preventable. 

•	 In the EPA Events Letter, EPA takes the position that the requiremen1 for an exceptional 

event to be "not reasonably controllable or preventable" inherently implies "a 

requirement that the state demonstrate that anthropogenic sources contributing to the 

exceedance caused by the event were reasonably controlled." This interpretation of the 

EER appears to be inconsistent with the language of 40 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." Undm the legal 
definition, it is irrelevant what controls are in place on the day of an otherwise qualifying 

event if it can be shown that such controls would not have reduced emissions enough to 

prevent an exceedance anyway. 

•	 We also disagree with EPA's position that the EER justifies the use of Best Available 

Control Measures (BACM) as the "appropriate... level of control in evaluating whether 

reasonable controls are in place" in determining whether an event ma:1 qualify as 

exceptional under the EER. This interpretation is unsupported by the language of the 

EER and inconsistent with the intent of the EER. The purpose of the I=ER is to protect 

states from suffering the consequences of reclassification to a more sl~rious designation 

as a result of "exceptional" events for which the normal planning and regulatory process 

established by the CM is not appropriate. EPA's analysis of exceptic,nal events should 

not depend on elements of the normal planning process, including the area's particular 

attainment status. In other words, the standards for determining an e:cceptional event in 

a serious nonattainment area should be no different than determining one in a moderate 

area or in an attainment area. 

•	 We also object to EPA's incomplete and misleading characterization clf fugitive dust 

controls in Imperial County. In the EPA Events letter, EPA implies thct dust controls are 

not adequate because of concerns about fallowed lands and OHV-related contributions. 

On the contrary: 

>­ Farm lands produce significantly less emissions, taken as a wl10le or on a peracre basis, compared to remote desert lands in the County dUI~ in part to 

ICAPCD's adoption of Rule 806, which requires a host of conservation 

management practices to prevent, reduce and mitigate PM emissions from 

agricultural sources.' Rule 806 was adopted in November 2005, 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 the fact that EPA has worked with ARB and ICAPCD lor over a decade, 

including on the development of rules and BACM Technical Analysis beginning in 

2004 and analysis of the exceptional events beginning in 200E, EPA never raised 

concerns about OHV-related contributions until after the Exceptional Events 

documents were submitted by ARB in May 2009 and after the 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 of the 2009 Imperial County PMlO SIP. 

2 Imperial County 2009 PMlO SIP, Final Draft, August 2009 

3 69 FR 30035, May 26, 2004 

4 In addition, EPA did not raise these concerns while working with ARB and ICAPCD for over a year and a half on the 

Exceptional Events documentation or while working with ARB and ICAPCD for over two years on the development of 

the PMlO SIP, or during the 30-day public comment period on the Exceptional Events documellts (during which there 

were NO public comments submitted), or before the draft PMlO SIP was released. 

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somehow would have prevented any of the exceedences attributable to the 

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 transport to show how such transp,)rt affected the 

September 2006 Westmorland and Calexico exceedances (see Secticns 2.1.1 and 2.1.2 

of Attachment A). As discussed further in the attachment, EPA's interlxetation of the 

September 2006 exceedences is incorrect, and was not based on a sound technical 

understanding of the events associated with those exceedences. 

•	 EPA's decision making regarding the level of evidence/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 support the 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 of dust and wind transport as part of the exceptj,)nal events 

showing, yet has not clearly specified what level of detail (if an'() would be 

sufficient to convince EPA that the exceptional events beyond the District's 

reasonable control were responsible for the measured exceedances. 

).>	 Also, rather than considering the cumulative weight of the evidence showing that 

unpreventable exceptional events caused the exceedances at issue, EPA has 

chosen to evaluate each piece of supporting data separately a 1d conclude that 

each separate piece alone does not support a causal relations hip for the event. 

EPA has not considered the implications of this novel and troul)ling position 

regarding causality on SIP determinations and other regulato!) processes. 

).>	 For reasons that are detailed in Attachment A, we believe that the level of data, 

analyses, and documentation that would be required to meet EPA's apparent 

proof thresholds (Le., to satisfy the causality and "but-for" requ rements of the 

EER) here would exceed even the requirements for SIP planning itself. That is 

clearly inconsistent with the intent of the EER. The EER requires the weight of 

evidence to be taken as a whole, and rejecting flagged data is tantamount to a 

determination that "the exceedances were caused by recurrin£ anthropogenic 

sources" (see 72 FR 13574). EPA cannot reject ARB's documentation of the 

exceptional events without producing such proof sufficient to overcome the great 

weight of the evidence to the contrary. 

Based on the weight of available evidence and the established EER requirements and 

guidance, the events described in the ARB submittal clearly were exceptional events that 

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 EPA to reconsider its decision and concur with ARB's request to flag 

these exceedences as exceptional events, consistent with the intent and language of the EER. 

Failure to reverse this decision will not only result in a decision unsupported by the law or the 

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data, but also would create troubling precedent for both future exceptional eve'nt 

documentations and related SIP planning in the southwestern United States. Both results would 

be unacceptable, and could subject EPA to 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 Administrator for Air And Radiation, EPA Headquarters 

Deborah Jordan, Air Division Director, EPA Region IX 

James Goldstene, Executive Officer, ARB 

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