UNITED STATES ENVIRONMENTAL PROTECTION AGENC Y WASHINGTON, D.C. 20460

The Honorable Sara Parker Pauley Director 

## MAR 2 02015

Missouri Department of Natural Resources Lewis and Clark State Office Building 1101 Riverside Drive Jetierson City, Missouri 65102-0176
Dear Ms

. Pauley : OFFICE OF AIR AND RADIATI ON

I am writing to update you on the status of the U.S

. Environmenta l Protection Agency's progress in implementing the primary National Ambient Air Quality Standard (NAAQS) for sulfur dioxide (S02 ) set in 2010 at 7 5 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 addre ss designations for the remainder of the cou ntry in separate future actions.
On March 2, 20 1 5, the U.S. District Court for the Northern District of Cali fornia accepted as an enforceable order an agreement between the EPA and Sierra Club and Natural Resources Defense Counci l to reso lve li tigation 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, 2016 , th e second round by December 31 , 2017 , and the final round by December 31, 2020

. The EPA will complete th ese designations by designating areas as either nonattainment, unclassifiable/attainment, or unclassifiabl e
. In the first round ofdesignations, 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 of S02 in 2012 or emitted more than 2 , 600 ton s 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 fo ll ow to meet the July 2 , 2016 , deadline.
The EPA has identified the fo ll owing area in your state as one that may have a newly recorded violation of the 20 l 0 so2 standard based on preliminary air quality monitoring data collected between 2012 and 2014:
State County Air Quality Systems Monitor Location 2012 -2014 Preliminary Monitor Identification S02 Design Value Number (ppb) MO Iron 29-093-0034 347 Power Lane 76 Bixby, MO 65439

Internet Address (UR L) • http :// www.epa

. gov Recycled/Recyclable • Printed with Vegetable Oil Based Inks on 100% Postconsumer

. Process Chlo ri ne Free Recycl ed PaperThe EPA has also identified the following electric power plant sources in your state as meeting the criteria in the court's order: 2012 so2 20 12 S02 Emissions Rate State County Facility Name Emissions (lb/MMBtu) (tons) MO J ackson Sib l ey Generating Station 6,095 0.550 MO Scott Sikeston Power Station 5,243 0.620 MO Fr anklin Labadie Power Plant 42 ,235 0.571 The EPA will use the most recent available information when making de signation and boundary decisions for the indicated areas. I f you would like to submit updated recommend at ions and s upporting information for the EPA to consider for the affected areas in your state , we requ es t that you do so by

September 18 , 20 15. In addition , the EPA has identified the following electric power plant sources in th e neighboring states of Illinois , Kansas, and Nebraska that also meet the criteria established in the court's order, and may potentially be impacting your state: 2012 S02 20 12 S02 Emissions State County Facility Name Emissions Rate (lb/MMBtu) (tons) IL Mad i son Wood River Power Station 6,756 0.476 KS Linn La Cygne Generating Station 16,235 0 . 356 KS Wyandotte Nearman Creek Pow er Station 4,612 0.636 NE Otoe Ne braska City Station 16,766 0.354 You may wish to discuss the designation for these areas with representatives of Illinois, Kansas, and Nebraska, and provide your own designation recommendations for th e potentially affected areas in your state . Again , please provide any informat ion you would like us to consider by September 18, 2015. The EPA has updated its March 24, 2011, designation guidance for the 2010 S02 standard to support analysis of designations a nd boundaries for these next rounds of designations. The updated guidance can be found on the EPA 's website at http ://epa .gov /airqualitylsulfurdioxidelguidance. html. The EPA has also provided two technical assistance documents that provide advice on the use of modeling and monitoring data when determining if an a rea is meeting or not meeting the 2010 S02 standard. These documents can be fo und on the E PA's website at http: // epa.gov/airquality/su?furdioxide / implement . html. The court's order directs the EPA to complete the second round of area designations by December 31 , 2017. These designations would a ddress areas where s tate s 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". Thi s rule, which was proposed in the Federal Register o n May 13, 2014 , would direct state and triba l air agencies to provide data to characterize

current air quality in areas with lar ge sources of S02 if s uch areas do not have sufficient air qualitymonitoring in place to identify maximum S02 concentrations. The data collected as a result of this proposed rule would be used in the designation s process. Lastly, the court's order directs the EPA to designate all remaining areas by December 31, 2020. The EPA will pro vide states with additional information on the designations process associated with these later deadline s at a later date.
We look forward to continued dialogue with you and your staff as we work toge ther to implement the 20 I0 S02 standard and ach ieve its intended public health protection. For additional information regarding designations for the 20 l 0 so2 standard, please visit our website at www.epa.gov /

so2designations. Should you have any questions, please do not hes itate t o call me or Scott Math ias of my staff at 919-541-5310 and mathias.scoll@ epa.gov. Sincerely,

J anet G. McCabe Acting Assistant Administ rator
Enclosure

cc: Mark Hague EPA Region 7 Acting AdministratorENCLOSURE
TIMELfNE FOR 20 I0 PRIMARY S(h NAAQS DESIGNATION PROCESS FOR AREAS ASSOCIATED WITH JULY 2, 2016, COURT-ORDERED D EADLINE* 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 notifi es states concerning any o /a J anu ary 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, 20 16 The EPA pub li shes pub lic notice of state o/a February 3, 2016 recommendation s and the EPA's intended modification s and initiat es 30-day public comment period End of 30 -day public comment period o/a March 4, 2016 States provide additional information to o /a April 8 , 2016 demonstrate why an EPA modification is inappropriate The EPA promulgates final 

### S02 area No later than Jul y 2 , 2016 de signations (no later than 16 months from Court Order) * The court 's order directs the EPA to promulgate additional round s ofdesignatiOns by December 3 1 , 2017 , and by December 31 , 2020. 

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