UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGTON , D

. C

. 20460

The Honorable Robert Martineau Commissioner 

## MAR 2 02015

Tennessee Department of Environment and Conservation 3 12 Ro sa L. Parks Avenue William R. Snodgrass Tennessee Tower Nashville, Tennessee 37243 Dear Mr. Martineau: OFFIC E O F AIR AND RAD IAT IO N

I am writing to update you on the status ofthe U.S. Environmental Protection Agency's progress in implementing the primary National Ambient Air Quality Standard (NAAQS ) for sulfur dioxide (S02) set in 20 I0 at 75 parts per billion (ppb) as a 1-hour average. In July 2013 , the EPA identified areas in 16 states as nonattainment and expressed the intent to address designations for the remainder of the country in separate future actions. On March 2, 2015, the U .S

. Di str ict Court for the Northern District of Ca lifornia accepted as an enforceable order an agreement between the EPA and Sierra Club and Natural Re sources Defense Council to resolve litigation concerning the deadline for completing the designations. The court's order directs the EPA to complete designations in three additional rounds : the first round by July 2, 2016, the second round by December 31, 2017, and the final round by December 31, 2020. The EPA will complete these de signa tions by designating areas as either nonattainment, unclassifiable/attainment, or unclassifiable

. In the first round of designations, the EPA will designate two groups of areas: 1) areas that have newly monitored vio lations of the 2010 S02 standard, and 2) areas that contain any stationary source that according to the EPA's Air Markets Database either emitted more than 16,000 tons of S02 in 2012 or emitted more than 2,600 tons of S02 and had an emission rate of at least 0.45 lbs S02/mmbtu in 2012 and that has not been announced (as of March 2, 2015) for retirement. In the enclosure to this letter, the EPA provides the schedule we intend to follow to meet the July 2, 2016, deadline

. The EPA has identified the following electric power plant source in your state as meeting the criteria established in the court's order:

Internet Add ress (U RL) • htt p :// www.epa
.gov Recyc led/ R ecycl abl e • Pri n ted w ith Vege table Oil Based I n ks on 100% Postconsumer, Process Chlo ri n e F ree Recyc led Pape r2012 S02 2012 S02 State County Fac ility Name Emi ssio ns Emissions Rate (to ns) (lb/mmbtu) TN Sumner TV A: Gallatin Foss il Plant 21,732 0.623 The E PA wi ll use the most recent available information when making designation and boundary decisions fo r the indicated area . If you wou l d like to submit an updated recommendation and supporting informatio n for the EPA to consider for the affected area in your state, we request that you do so by September 18, 2015. The EPA has updated its March 24, 2011, designation guidance for the 201 0 S02 sta ndard to support analysis of designations and boundaries for these next r ounds of designations. The updated guidance can be found on the EPA's webs ite at http://epa.gov/airquality/sul[urdioxide/guidance.html. The EPA has also provided two technical assistance documents that provide advice on th e use of modeling and monitor i ng data when determining if an area i s mee t ing or not meeting the 2010 S02 standard. These documents can be found on the E PA' s website at http :IIepa. gov/airquality/sul{urdioxide/implement. html.

The court's order directs the EPA to complete the second round of area designations by December 31, 2017. These designations would address areas where states have not installed and begun operating a new S02 monitoring network meeting the EPA's specifications referenced in our proposed rule titled, "Data Requirements Rule for the 1-hour S02 primary NAAQS" . This rule , which was propos e d in the Federal Register on May 13,2014, would direct s tate and tribal

air agencies to provide data to characterize current air quality in areas with large sources of S02 if such areas do not have sufficient air quality monitoring in place to identify maximum S02 concentrations. The data collected as a result of th is proposed rule would be used in the designations process. Lastly, the court's order directs the E PA to designate all remaining areas by December 31, 2020. The EPA will provide states with additional information on th e designations process associated with these later dead l ine s at a later date. We look forward to continued dialogue with you and your staff as we work together to implement the 2010 S02 standard and achieve its i ntended public health protection. For additional inf o rmation regarding designations for the 2010 S02 standard, please visit our website at www.epa.gov/so2designations. Should you ha ve a n y questions, please do not hesitate to call me or Scott Ma t hias of my staff at 919-541-5310 and mathias.scott@epa.gov . Sincerely,**~-rG /~L--**  Janet G. McCabe Acting Assistant Administrator Enclosure cc: Heather McTee r

EPA Region 4 AdministratorENCLOSURE TIMELINE FOR 2010 PRIMARY S02 NAAQS DESIGNATION PRO CESS FOR AREAS ASSOCIATED WITH JULY 2 , 2016, COURT-ORDERED DEADLINE* Milestone Date** Court Order March 2, 2015 States may submit updated recommendations No later than September 18 ,2015 and s upporting information for area designations to the EPA The EPA notifies states concerning any o/a January 22,2016, but absolutely no later intended modifications to their than 120 days prior to final designations, 

### i.e., recommendations ( 120-day letters) March 2, 2016 The EPA publishes public notice of state o/a February 3, 2016 recommendations and the EPA's intended modifi cations and initiates 30

-day public comment period End of 30-day public comment period of a March 4, 2016 States provide addi ti onal information to o /a April 8, 20 16 demonstrate why an EPA modification is inappropriate The EPA promulgates final S02 area No later than July 2 , 2016 designation s (no later than 16 months from Court Order)

.. * The court ' s order directs the EPA to promulgate additional rounds ofdesignatiOns by December 31, 2017 , and by December 31 , 2020. ** o/a = on or about