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December 9, 2010 

Mr. Shawn M. Garvin (3RAOO) 

Regional Administrator, Region III 

U.S. Environmental Protection Agency 

1650 Arch Street 

Philadelphia, PA 19103-2029 

The purpose of this letter is to inform you that the Department of Natural 

Resources and Environmental Control (the Department) intends to submit a formal 

supplement the State Implementation Plan (SIP) revision submitted to EPA on 

September 17, 2009. That SIP revision was submitted to satisfy the requirements of 

Section 11 O(a)(l) and 11 0(a)(2) ofthe Clean Air Act (the Act) pursuant to 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 of a technical analysis in support ofthe 

Department's September 17,2009 submittal's provisions to address the infrastructure 

SIP requirements of Section 11 0(a)(2)(D)(i)(I) for interstate transport. I am submitting 

that supplemental technical analysis today and requesting that EPA process it in parallel 

with the 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 of failure to submit. Therefore, the September 

17,2009 SIP submission made by the Department was timely. However, on September 

25, 2009, EPA issued a guidance document entitled, "Guidance on SIP Elements 

Required Under Sections 11 O(a)(l) and (2) for the 2006 24-Hour Fine Particle (PM2S) 

National Ambient Air Quality Standards (NAAQS)," which provided guidance on 

addressing the "infrastructure" elements for SIPs required under Sections 11 O(a)( 1) and 

110(a)(2) of the 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 to 
Letter to Shawn M. Garvin 

December 9, 20 I0 

Page 2 

interstate transport found at 11 0(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 a rule to address interstate transport in the eastern portion of the continental 

United States (the Transport Rule). This rule would replace the vacated Clean Air 

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 or the CAIR replacement 

rule without facing findings of failure to submit for not meeting the October 17,2009 

due date for submittal of the 110(a)1) and 110(a)(2) infrastructure SIP elements pursuant 

to EPA's October 17, 2006 promulgation of the 24-hour NAAQS for PM25. Therefore, 

Delaware made a timely SIP submission in which the Department cited to its own SIPapproved regulations to reduce PM 2.5 precursor emissions of sulfur dioxide (S02) and 

nitrogen oxides (NOx) from electric generating units, industrial boilers, and peaking 

units to address the interstate transport requirements of 11 0(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 guidance document. 

Since the time of our September 17, 2009 SIP submittal, EPA proposed the 

Transport Rule (August 2,2010). In that proposal, EPA concluded that the State of 

Delaware was to be included among the states covered by the Transport Rule. On 

October 1,2010, the Department submitted timely comments to EPA's rulemaking 

docket for proposed Transport Rule including extensive technical data and information 

to support our contention that Delaware should not be included in the Transport Rule. 

The comments, data and information submitted by the Department on the proposed 

Transport Rule address EPA's September 25,2009 guidance for a technical analysis to 

demonstrate that the enforceable reductions in precursor emissions of PM 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 on the Transport Rule as the technical analysis in support of our 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 the public notice and announcement of hearing. 

Upon completion of the Act's required public participation procedures, the Department 

will formally submit this technical analysis as a supplement to its September 17,2010 

SIP submission to satisfy 11 0(a)(2)(D)(i)(I) for interstate transport along with the 

associated administrative materials required by 40 CFR Part 51 Appendix v. In the 

interim, the Department requests that EPA consider and parallel process the technical 

analysis enclosed with this letter in any proposed rulemaking on its September 17, 2009 

SIP submission while we complete the required public participation procedures in order 

to submit that technical analysis as a formal and official supplement to that SIP 

submission. The Department intends to submit the technical analysis as a formal 

supplement to the September 17, 2009 SIP submission immediately upon completion of 
Letter to Shawn M. Garvin 

December 9,2010 

Page 3 

public participation procedures and well before such time as EPA would be prepared to 

take final action on that SIP. 

Thank you for your consideration of the above recommendations. If you have 

any questions concerning this submittal or would like to discuss it further, please contact 

Mr. Ali Mirzakhalili, the Director of our Division of Air Quality, at (302)739-9402. 

lin P. O'Mara 

Secretary 

Enclosures