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

The Hono rable Becky Keogh Directo r 

## MAR 2 

## tl 2015

Ark ansas Department o f Enviro nmental Qualit y 530 I No rthshore D rive North L itt le Rock , Arkansas 72 1 18-53 17
Dear M s
. Keo g h: OFFICE OF AIR AND RADIATION

I am writing to update you on the statu s of the U.S. Environmental Protect io n Agency's progress in implementing the primary National Amb ient A ir Quality Sta ndard (NAAQS) for su l fur dioxide (S 0 2 ) set i n 20 I 0 at 75 p arts per bi lli on (ppb) 

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- hour average. In Jul y 2013, the EP A id e ntified areas in 16 states as nonattainm e nt and ex pr essed the intent to address de s ignations for the r e m ai nder of the country in separate future actions.
On March 2, 2015 , the U.S. D is trict Court for th e Northern District o f Ca lifornia accepted as an e nforceable o rder a n ag reeme nt b etwee n the EPA and Siena Club and Natural Resou rces Def ense Cou ncil to re so lve liti gation conce rnin g the deadline for comp le tin g the de s ig nations. The court's order directs the E PA to com pl ete des ignations in three addit ional rounds: the fi rst round by J ul y 2, 2016, the second round by D ecember 3 1 , 2017, and the final round by December 3 1 , 2020. The EPA w ill comp l ete these designation s by desig natin g areas as e ither nonattainment , unclassifiable/ attainment , or unclassi fiable.
In the firs t round of de s i g nat ion s, the EP A w ill d es ig n ate two g roups of areas: 1) areas that have ne w ly monitored v iolations of the 20 1 0 S02 standard , and 2) area s that contain any stati o nary source that acco rd ing to the EPA's A ir Markets Database ei th er em itt ed more than 16 , 000 to ns of S02 in 2012 or em itted more than 2,600 ton s of S02 and had an emission rate of at least 0.45 lb s S 0 2 /mmbtu in 20 12 and that has not been announced ( as of March 2 , 20 15 ) for ret irement. In th e enclosure to this letter, the E PA provides the sched u le we intend to follow to meet the July 2 , 2016 , deadline.
T he EP A has ide nti fied t he fo ll owi ng electric power plant so urces in yo ur state as meeting the criteria estab li s hed in the court 's o r der:
2012 S0 2 2012 so2 S ta te County Facility Name Emi ss ion s Emi ss ions Rate (to ns) (lb/ mmbtu ) AR Independenc e Independence Power Pl ant 32 , 974 0.586 AR J efferson White Blu ff Power Plant 

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Internet Address (URL) • http ://www

. epa

. gov Recycled/Recyclable • Pri nted with Vegetab l e Oil Based Inks on 100% Postconsumer

. Process Chlorine Free Recyc led PaperThe EPA will use the most recent available information when making designation and boundary decisions for the indicated areas. If you would like to submit an updated recommendat i on and supporting informat i o n for the EPA to co n s i der for the affected areas in your state, we r e q uest that you do so by September 1 8, 2015 . The EPA has updated its March 24 , 20 1 1, designation guidance for the 2010 S0 2 standard t o support analysis of designations and boundaries for these next rounds of designations. The updated guidance can be found on the EPA ' s web s ite at hap :// epa.go v l airqualit v l sul{urdioxid e / guidance . html. T he EPA ha s also provided two technical assistance documents that provide advice on the use of modeling and monitoring data when determin i ng if an area is meeting or not meet i ng the 20 I 0 S02 standard. These documents can be found on the EPA's webs i te at http :/ / epa.gov/airqualit yl sul(urdioxidelimplement.html. The court's orde r d i rects the EPA to c om plete the second ro u nd o f area des i g n ations b y D ecembe r 31 , 2017. These designations wou l d address areas where states have not ins t alled and begu n operat i ng a new S0 2 mon i toring network meeting the EPA's specifications referenced in our proposed rule ti t led , "Data

R e quirements Rule for the 1-hour S02 primary NAAQS " . This ru l e , which wa s proposed in the F e d e r a l R eg ister on May 13 , 2014 , would di r ect state and triba l air agencies to provide data to characterize current a i r quality in area s with large sources of S0 2 if s uch areas do not have s ufficient air quality monitoring in place to identify maximum S0 2 concentrations. The data collected as a result of this

proposed rule would be used in the designa ti ons process. Lastly, t he cou r t's order directs t he EPA to designate all rema i ni n g a r eas by Dece mb e r 3 1 , 2020. The EP A w ill provide states wi t h a d d it ional i nformatio n o n t h e d esignat i o n s p r ocess associated w i th t h ese l a ter d ea dlin es at a l ater date. We look forwa r d to continued dialogu e with you and your staff as we work together to implement the 2010 S0 2 standard and achieve its intended public health protection. For additional information r eg arding designations for the 20 1 0 S0 2 standard , please visit our website at www.epa . gov / so2d e si g nation s . Should you have any questions, please do not h es ita t e to call me or Sc o tt

Mathias of my staff at 919-541-5310 and mathia s. scoll @ epa.gov. S i ncerely, Janet G. McCabe Acting A s sis t ant Admin i strator Enclosure cc: Ron C urr y E P A R eg i o n 6 Ad m i n istratorENCLOS URE


### TfMELINE FOR 2010 PRIMARY S02 NAA QS DESIGNATION PRO CESS FOR AREAS ASSOCIATED W ITH JU LY 2 , 20 16 , COUR T -ORDERED DEADLINE* Milestone Date** 

### Court Order March 2 , 20 I 5 State s may s ubmit updated recommendation s No later than September 18, 2015 and supporting inform atio n for area designation s to the EPA The EPA notifies states co ncerning any o /a Janua ry 22, 2016 , but abso lutely no later intended mod ifications to the ir than 120 days prior to final designations , i.e. , 

### recomme ndations (120-day letters) March 2 , 2016 The EPA publishes publi c notice of state o/a February 3 , 20 16 rec ommendations and the EPA 's intended modificati ons and i nitiate s 3 0-day public comment p eriod End of 30-day public commen t period o/a March 4 , 20 16 States provide additional information to o/a April 8 , 20 16 demonstrate why an EPA modification is inappropriate The EPA promulgate s fin a l S02 area No later than Ju ly 2 , 20 16 de s ignations (no later than 16 mo nths from Court Order)

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### * The court 's order directs the EPA to promulgate addttlonal rounds of dest g natwns by December 3 1 ,20 17 , and by December 31 , 2020.
** o/a = on or about