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TAUNA M. SZYMANSKI

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FILE NO: 31531.4600 05 July 10, 2013

Vi a Electronic Mail

Ms. Gina McCarthy

Assistant Administrator for Air and Radiation U.S. Environmental Protection Agency 1200 Pennsylvania Avenue, NW

Mail Code 6101A Washington, D.C. 20460

Email: mccarthy.gina@epa.gov

Re: Request for Extension of Commen t Period on the Proposed Rule Regarding “Implementation of the 2008 National Ambient Air Quality Standards for Ozone: State Implementation Plan Requirements”

Dear Assistant Administrator McCarthy:

On June 6, 2013, the U.S. Environmental Protection Agen cy (“EPA”) published in the Federal Register its proposed “Implementation of the 2008 National Ambient Air Quality Standards for Ozone: State Implementation Plan Requirements” (“Proposed Rule”), and requested that comments on the Proposed Rule be filed by August 5, 2013. 78 Fed. Reg. 34,178. We are writing on behalf of the Utility Air Regulatory Group (“UARG”) to request a 30

- day extension of this comment period, to September 4,

2013. 1

The Proposed Rule is lengthy, detailed and complex, with multiple pro posals and

alternatives listed for consideration and comment. There are at least two dozen discrete topics relating to the Proposed Rule and the implementation of the 2008 ozone National Ambient Air Quality Standards on which EPA requests comment. Each o f

1 UARG is a voluntary, ad hoc , not

- for

- profit association of electric generating companies and organizations and national trade associations. UARG’s purpose is to participate on beha lf of its members collectively in EPA’s rulemakings and other Clean Air Act administrative proceedings that affect the interests of electric generators and in litigation arising from those proceedings.Assistant Administrator Gina Mc Carthy July 10, 2013 Page 2

these topics requires careful consideration, analysis, and the development of substantive responses. The voluminous number of diverse topics on which EPA specifically requests comment merits additional time to prepare responses.

In addition to the many legal and policy aspects of the Proposed Rule requiring consideration and response, EPA requests comment on aspects of the Proposed Rule that necessitate technical and scientific analysis and input. For instance, several aspects of the Proposed Rule invo lve modeling and model performance issues. Furthermore, EPA’s complicated proposal to substitute NOx reductions for VOC reductions in certain circumstances has potential ramifications that merit analysis by technical experts.

UARG is consulting with mo delers and scientists with the goal of providing EPA with

detailed , informed comments on this highly technical Proposed Rule. EPA specifically requests comment on these technical issues, and adequate collaboration

with outside consultants and scientist s takes more time than the time typically required to develop comments on legal and policy issues alone. For these reasons, UARG believes that extending the public comment period in this case would further the Agency’s goal of creating a robust and delibe rative record in this rulemaking.

In consideration of these factors, UARG respectfully requests that EPA extend the comment period on the Proposed Rule t o September 4, 2013.

We appreciate your consideration of this request and look forward to your pr ompt

response. Thank you for your attention to this matter.

Sincerely,

Tauna M. Szymanski Lucinda Minton Langworthy

cc: Dr. Karl Pepple, OAQPS, pepple.karl@epa.gov Butch Stackhouse, OAQPS, stackhouse.bu tch@epa.gov

EPA Docket EPA

- HQ

- OAR

- 2010

- 0885 (via electronic submission)