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SECR£TAR¥ STATE Q 0 AWARl> DEPARTMEN OF N TURAL RESOURCES
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89 /(1 NGS H lGHWAY**P>lQ~F:** 1302 I 7 9·g000**OOVI!.~** 0 LAWARE J 990 I FAIl: 130Z 739-6.242
December 9, 2010

Mr. ShawnM. Garvin (3RAOO) Regional Administrator, Region III U.S. Environmental Protection Agency 1650 Arch Street Philadelphia, PA 19103-2029

Thepurpose ofthis letter is to inform you that the Department ofNatural Resources and Environmental Control (the Department) intends to submit a formal supplementthe State Implementation Plan (SIP) revision submitted to EPA on September 17, 2009. That SIP revision was submitted to satisfy the requirements of Section 11O(a)(l) and 110(a)(2) oftheClean AirAct (the Act) pursuantto the National Ambient Air Quality Standards (NAAQS) for Fine Particles (PM2.S) promulgated by the United States Environmental Protection Agency (EPA) on October 17,2006 (71 FR 61224). These requirements are commonly referred to as Section 110 infrastructure requirements. The supplement consists ofa technical analysis in support ofthe Department's September 17,2009 submittal'sprovisions to address the infrastructure SIP requirements ofSection 110(a)(2)(D)(i)(I) for interstate transport. I am submitting that supplementaltechnical analysis today and requesting that EPA process itin parallel withthe September 17, 2009 SIP submission while the Department completes the public participation procedures necessary to submit the technical analysis as a formal supplement to our SIP revision request.

Under the Act, States are required to submit SIP revisions to satisfy Section 110(a)(I) and Il0(a)(2) by no later than three years from the date EPA promulgates a
new or revised NAAQS or face fIndings offailure to submit. Therefore, the September 17,2009 SIP submission made by the Departmentwas timely. However, on September 25, 2009, EPA issued a guidance document entitled, "Guidance on SIP Elements Required Under Sections 11O(a)(l) and (2) for the 2006 24-HourFine Particle (PM2S) National Ambient Air Quality Standards (NAAQS)," which provided guidance on addressingthe "infrastructure" elements for SIPsrequired under Sections 11O(a)(1) and 110(a)(2) ofthe Act for the 2006 24-hour PM2 5 NAAQS. According to this guidance document, any state's SIP submission to address the infrastructure element related toLetter to Shawn M. Garvin December 9, 20I0 Page 2

interstatetransport found at 110(a)(2)(D)(i)(I) must be supported by an "adequate technical analysis." This guidance document further states that it is EPA's intention complete arule to address interstate transport in the eastern portion ofthe continental United States (the Transport Rule). This rule would replace the vacated CleanAir Interstate Transport Rule (CAIR) and would assist states with obligations to address interstate transport that significantly contributes to nonattainment in another state.

However, states could not wait for EPA's SIP guidance orthe CAIRreplacement rule without facing findings offailure to submit for not meetingthe October 17,2009 due date for submittal ofthe 110(a)1) and 110(a)(2) infrastructure SIP elements pursuant to EPA's October 17, 2006 promulgation ofthe 24-hourNAAQS for PM25. Therefore, Delaware made a timely SIP submission in whichthe Department cited to its own SIPapproved regulations to reduce PM 2.5 precursor emissions ofsulfur dioxide (S02)and nitrogen oxides (NOx) from electric generating units, industrial boilers, and peaking units to address the interstate transport requirements of 110(a)(2)(D)(i)(I). Our September 17, 2009 SIP submittal did not include the technical analysis called for in EPA's September 25, 2009 guidancedocument.

Since the time ofour September 17, 2009 SIP submittal, EPA proposed the Transport Rule (August 2,2010). In thatproposal, EPA concludedthat the State of Delaware was to be included amongthe states covered by the Transport Rule. On October 1,2010, the Department submitted timely comments to EPA'srulemaking docket for proposedTransport Rule including extensive technical data and information
to support ourcontention that Delaware should notbe included in the Transport Rule. The comments, data and information submitted by the Department on the proposed Transport Rule address EPA's September25,2009 guidance for a technical analysis to demonstrate that the enforceable reductions in precursor emissions ofPM 25 required by the Delaware SIP satisfy 110(a)(2)(D)(i)(I).

Therefore, the Department is using the comments, data, and information we submitted onthe Transport Rule as the technical analysis in support ofour September 17,2009 SIP revision to comply with EPA's September 25, 2009 guidance document. Enclosed please find the technical analysis we intend to make available for public
comment and hearing pursuant to the requirements IIO(a)(l) and 110(a)(2) for SIP revisions and a pre-publication copy thepublic notice and announcement ofhearing. Upon completion ofthe Act's requiredpublic participationprocedures, the Department will formally submit this technical analysis as a supplement to its September 17,2010 SIP submission to satisfy 110(a)(2)(D)(i)(I) for interstate transport along withthe associated administrative materials requiredby 40 CFRPart 51 Appendix 

### v. In the interim, the Department requests that EPA consider and parallel process thetechnical analysis enclosed withthis letter in any proposed rulemaking on its September 17, 2009 SIP submission while we complete the required public participationprocedures in order
to submit that technical analysis as aformal and official supplement to that SIP submission. The Departmentintends to submit the technical analysis as aformal supplement to the September 17, 2009 SIP submission immediatelyupon completion ofLetter to ShawnM. Garvin December 9,2010 Page 3

public participationprocedures and well before such time as EPA would be prepared to take final action on that SIP.

Thank you for your consideration ofthe above recommendations. Ifyou have any questions concerning this submittal orwould like to discuss it further, please contact Mr. Ali Mirzakhalili, the Director ofour Division ofAir Quality, at (302)739-9402.

lin P. O'Mara Secretary

Enclosures