UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGTON, D.C. 20460

The Honorable Craig Butler Director Oh io Environmental Protection Agency 50 West Town Street, Suite 700 Co lumbus, Ohio 43215
Dea r Mr. Butler: 

## MAR 2 02015

OFF I CE OF AIR AND RADIATION

I am writing to update you on the status of the U.S. Environmental Protection Agency's progress in implementi ng the primary National Ambient Air Quality S tandard (NAAQS) for sulfur dioxide (S02) set in 2010 at 75 parts per bill ion (ppb) as a 1-hour average. In July 2013, the EPA identified areas in 16 states as nonattainment and expressed the intent to address des ignations for the remainder of the country in separate future actions.
On March 2, 2015, the U

. S

. District Court for the Northern District of California accepted as an enforceable order an agreement between the EPA and Sierra Club and Natura l Resources Defense Council to resolve litigation concerning the deadline for completing the designations. The court's ord er directs the EPA to complete designations in three additional rounds : the fi r st round by Jul y 2 , 2016, the second round by December 31, 2017, and the final roun d by December 31, 2020. The EPA will complete these designations by designating areas as either nonattainment, un classifia ble/a ttainment, or unclassiiiable.
In the first round of designations, the EPA will designate two groups of areas: 1) areas that have newly monitored v iolations 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 802 in 2012 or emitted more than 2,600 tons of802 and had an emi ssion rate of at least 0.45 lbs 802/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.
T he EPA has identified the fo ll owing electric power p lant sources in your state as meeting the criteria established in the cour t 's order:
2012 802 20 12 S02 State County Facility Name Emissions Emiss ion s Rate (tons) (lb/mmbtu) General James M Gavin OH Gallia Power Plant 31,269 0.360 W HZimmer OH Clermont Generating Station 11,975 0.525

Internet Address (U RL) • http :// www

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. gov Recycled/Recyclable • Printed with Vegetable Oil Based I nks on 100% Postconsumer, Process Chlorine Free Recycled PaperThe EPA will use t he most recent ava il able inf ormation when making designation and boundary decisions for the indicated areas. If you would like to submit an updated recommendation and supporting information for the E PA to cons id er for the affec t ed areas in your state, we request that you do so by Septembe r 18, 2015. The E PA has updated its March 24, 2011, designation gu id ance for the 2010 S02 standard to support analys i s of designations and boundaries for these nex t rounds of designations. T he updated guidance can be found on the EPA ' s website at http :// epa.gov/airquality / sulfurdioxide l guidance.html. T he E PA has also provided two technical assistance documents that provide advice on the use of modeling and monitoring data when determin in g i f an area is meeting or not meeting the 2010 S02 standard. These documents can be found on the EPA's website at http :// epa.gov/airquality l sulfurdioxidelimplement.html. The court's order directs the EPA to complete the second round of area designat i ons by December 31 ,

20 1 7 . These des i gnations wou ld address a r eas where states have not insta ll ed and begun operating a n ew S02 monitoring network meeting the EPA's specifications referenced in our proposed rule t itl ed, "Data Requ i rements Rule for the 1- h our S02 primary NAAQS". This rule , which was proposed in the Federal Register on May 13 , 2014 , wou l d direct state and triba l ai r agencies t o provide data t o characterize cu r rent air quality i n areas with large sources of S02 if such areas do not have sufficient air quality moni t oring in place to identify maximum S02 concentrations. The data collected as a result of this proposed rule wou ld be used in the des i gnations process . L ast! y, the cour t 's or d er directs the EPA to des i gnate all remaining areas by December 3 1 , 2020 . The EPA w ill provide states with additional infom1ation on the designations process associated with these l ater deadlines at a later date. We look forward to continued dia l ogue w i th you and your staff as we work together to implement the 2010 S02 s t andard and achieve its intended public health protection. For additional inf o rmat ion regarding designations for the 20 I 0 S02 standard, please v i sit our webs i te at www.epa.gov/so2designations . Shou ld you have any questions, please do not hesitate to call me or Scott Mathias of my staff at 919-541-5310 and mathias . scott@epa.gov. Sincerely, Janet G. McCabe Acting Assistant Administ r ator Enclosure cc: Susan Hedman

EPA Region 5 Adm ini stratorENCLOSURE
TIMELINE FOR 20 10 PRIMARY S02 NAAQS DES IGNATION PRO CESS FOR AREA S ASSOCIATED WITH JULY 2, 2016, COU RT-ORDERED D EA DLINE* Milestone Date** Court Order March 2, 20 1 5 Sta tes may submit updated recommendations No later than September 18 , 2015 and supporting info rmation for area design ations to the E PA The EPA notifies states concerning any o/a January 22 , 2016, but absolutely no la ter intended modificati ons to the ir than 1 20 days prior to fmal designations, 

### i.e ., r eco mmendation s ( 1 20-day letters) March 2, 20 16 T he EPA publishe s public n otice of state o /aFebru ary 3, 20 16 recommendations and th e EPA ' s intended modifications and initiates 30-day public comment period End of 30-day public co mment period o/a March 4, 2016 States provide additiona l information to o/a April 8 , 20 1 6 demonstrate why an EPA mod ifica tion is inappropriat e The EPA promulgates final S02 area No late r than July 2, 2 016 des ignations (no later than I 6 months from Court Order)



### .. * The court's order directs the EPA to promulgate additional round s of designatiOns by December 31 , 20 17 , and by December 31 , 2020. 

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