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

The Honorable R. Bruce Scott Commissioner 

## MAR 2 02015

Kentucky Department for Environmental Protection 300 Fair Oaks Lane Frankfort, Kentucky 4060 1
Dear Mr. Scott : OFFICE OF AIR AND RADIATION

I am writing to update you on the status ofthe U.S. Environmental Protection Agency's progress in implementing the primary National Ambient A ir Quality Sta ndard (NAAQS) for sulfur dioxide (S02) set in 2010 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. District Court for the Northern District of California accepted as an enforceable order an agreement between the EPA and Sierra Club and Natural Resources Defense Council to resolve litigation concerning the dead line for completing the designations. The court's order directs the EPA to complete designations in three additional rounds: the first round by July 2 , 20 16, the second round by December 31, 2017, and the final round by December 31, 2020. The EPA will complete these designations by designating areas as either nonattainment, unclass ifiable/attainment, or unclassifiable.
In the first round of designations, the EPA will designate two groups of areas: 1) areas that have newly monitored violations 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 ofS02 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, 20 15) 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 sources in your state as meeting the criteria established in the court's order : 2012 S02 20 12 so2 State County Facility Name Emissions Emissions Rate (tons) (lb/mmbtu) KY Ohio D B Wilson Generating Station 7,387 0.452 

### KY Pu laski JohnS. Cooper Power Station 

### 7,428 1.075

Internet Address (URL) • h ttp ://www

. epa

.gov Recycled/Recyclable • Printed with Vegetable Oil Based I nks on 100% Postconsumer, Process Chlorine Free Recycled PaperThe EPA will use th e most recent available information when making designation and boundary decisions for the indicat ed areas. If you would like to s ubm i t u pdated recommenda t ions and supporti ng in formation for the EPA to consider for the affected areas in your state, we request that you do so by September 18,2015 . In addition, the EPA has identified the following electric power plant sources in the neighboring states of Illinois, Indiana, and Ohio that a l so meet the criteria estab lish ed in the court's order, and may potentially be impacting your state: 2012 so2 2012 so2 State County Facility Name Emissions Emissions Rate (tons) (lb/mmbtu) IL Mas sac Joppa Steam Coal Power Plant 16,991 0.475 IN Posey A B Brown Generating Station 7,091 0.521 IN Jefferson C li fty Creek Power Plant 52,839 1.767 OH Clermont W H Zimmer Generating Station 11,975 0.525 You may wish to discuss the designation for these areas with representatives of Illinois, Indiana, and Ohio, and provide your own designation recommendation for the potentially affected areas in your state. Again, please provide any i nformation you wou l d li ke us to consider by Septembe r 18, 2015 . The EPA has updated i ts March 24,2011, designation guidance for the 2010 S02 standard to suppo rt analysis of designations and boundaries for these next rounds of designations. The updated guidance can be found on the EPA's website at http :IIepa . govlairqualitvlsul(urdioxide/guidance. html. The EPA has also provided two techn ica l assistance documents that provide advice on the use of modeling and monitoring data w hen determining if an area is meeting or not meeting the 20 I 0 S02 standard. These documents can be found on the EPA's website at http :/ /epa.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 des i gnations would address areas where states hav e not insta ll ed and begun operating a new S02 monitoring network meeting the EPA's s pecifica tions referenced in our proposed rule titled , "Data Requirements Rule for the 1- hour S02 primary NAAQS". This rule, which was proposed in the Federal Register on May 1 3, 2014, would direct state and triba l air agencies to provide data to characterize

current air quality in areas with la rge sources of S02 if such areas do not have sufficie n t air quality monitoring in place to id en t ify maximum S02 concentrations. The data collected as a result of this

proposed rule would be used i n the designations process. Lastly, the court's order directs the EPA to designate all remaining areas by December 31, 2020 . The EPA will provide states with additional information on the designations process associated wit h these l ater deadlines at a later date.We look forward to continued dialogue with you and your staff as we work together to implement the 2010 

### SOz standard and achieve its intended public health protection. For additional information regarding designations for the 2010 

## so2 standard , please visit our website at www.epa.gov /

so2designations. Should 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 Administrator Enclosure

cc: Heather McTeer EPA Region 4 Administrator

### ENCLOSURE TIMELINE FOR 2010 PRIMARY S02 NAAQS DESIGNATION PROCESS FOR AREAS ASSOCIATED WITH JULY 2, 2016 , COU RT

-ORDERED DEADLINE* Milestone Date** Court Order March 2 , 20 15 States may submit updated recommendations No later than September 18 , 2015 and supporting information for area designations to the EPA The EPA notifies states concerning any o/a January 22 , 20 1 6 , but absolutely no later intended modifications to their than 120 days prior to final designations, i.e ., recommendation s ( 120-day letters) March 2 , 20 1 6 T he EPA publi shes pub lic notice of state o/a February 3 , 20 16 recommendations and the EPA's intended modifications and initiates 30-day public comment period End of 30

-day public comment period o/a March 4 , 2016 States provide additiona! information to o/a April 8 , 2016 demonstrate why an EPA modification is inappropriate T he EPA promulgates fina l S02 area No later than July 2 , 20 1 6 des ignation s (no later than 16 months from Court Order)



### .. *The court's order directs the EPA to promulgate addttlonal rounds of destgnahons by December 31 , 2017 , and by December 31 , 2020.
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