Stuart Spencer, Chief Air Division UNITED STATES ENVIRONMENTAL PROTE CTION AGENCY REG ION6 1445 ROSS AVENUE , SUITE 1200 DALLAS TX 75202-2733

October 20, 2015

Arkansas Department of Environmental Quality 5301 Northshore Drive North Little Rock, AR 72118-5317

Dear Mr. Spencer:

Thank you for the recommendations regarding the attainment status of selected areas in Arkansas under the 2010 sulfur dioxide (S02) national ambient air quality standard (NAAQS) that your agency sent to us on September 11, 2015. As you know, we are subject to a March 2, 2015, court order directing us to promulgate S02 designations for these areas under section 107 of the Clean Air Act by July 2, 2016. Specifically, we are required to promulgate designations for these areas because they contain sources meeting the S02 emissions criteria identified in the consent decree. The information you provided on September 11 , 2015, will greatly help us meet this duty, and ensure protection of public health in Arkansas.

In addition to the information you have provided, we have recently received modeling and related information from the Sierra Club that is relevant to a subset of the areas to be addressed by July 2, 2016. In your state, we have received information pertinent to the area near to the following power plants: White Bluff Steam E lectric Station and Independence Steam Electric Station. We are enclosing a compact disc that contains this informatio n. Please let us know if you have any questions about the information we hav e received or if you need any additional information.

I am writing to solicit your review of the information that Sierra Club has provided, so that the EPA can base its designation decisions on the best available information. The Clean Air Act provides for d esignat i on s to be d evel oped through a partnership of state agencies and th e EPA, however we also believe it is important to consider significant and relevant information that members of the public provide to us. Consistent with the structure of the Clean Air Act, we believe that the best first step in address ing this informati on would be for your agency to provide its review of this information. Since the Sierra Club's recommendation differs from your recommendation, we would welcome your commentary generally on the informa tion as well as your detailed review of the elements of Sierra Club's analysis. To the extent practicable, we would appreciate quantitative comparisons of data used in Sierra Club's analysis compared to the data used in your analysis, to he lp us evaluate the elements of the two analyses.

We would appreciate your review of Sierra Club's information by November 17, 2015. Your timely
rev iew would prov ide us valuable assistance in our review of your designation recommendations and de vel opment of our intended designations, which we are aiming to complete by the end of January 2016. We will then pub lish notice of our intended des ignat ions for public comment, and, as required by the I n t

ernet Address (U RL) • h ttp://www

.epa. g ov/reg i on6 Recyc l ed/Recyc l able • P ri nt ed wi t h V egetabl e O i l Based I nks on 100% Postcon sum er, Process C h l o rin e Fr ee Recycled P aperClean Air Act, promulgat e final designations no soo ner th an 120 days a ft er giv in g you notice of th e m. Please contact me or James E. Grady of my staff at 2 14-665-6745 or at grady.james @ epa.gov if you have any questions about this request.

En closure: cd Sincerely,

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# )~**re~·** Guy D on aldso n Chief Air Planning Section