UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON, D.C. 20460 

The Honorable Robert Martineau 

Commissioner 

MAR 2 0 2015 

Tennessee Department of Environment and Conservation 

3 12 Rosa L. Parks A venue 

William R. Snodgrass Tennessee Tower 

Nashville, Tennessee 37243 

Dear Mr. Martineau: 

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 Air Quality Standard (NAAQS) for sulfur 

dioxide (S02) set in 20 I 0 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 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 designations 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 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 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 Address (URL) • http://www.epa.gov 

Recyc led/Recyclable • Printed with Vegetable Oil Based Inks on 100% Postconsumer, Process Chlorine Free Recycled Paper 
2012 S02 2012 S02 

State County Facility Name Emissions Emissions Rate 

(tons) (lb/mmbtu) 

TN Sumner TV A: Gallatin Fossil Plant 21,732 0.623 

The EPA will use the most recent available information when making designation and boundary 

decisions for the indicated area. If you would like to submit an updated recommendation and 

supporting information 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 standard to 

support analysis of designations and boundaries for these next rounds of designations. The 

updated guidance can be found on the EPA's website at 

http://epa.gov/airquality/sul[urdioxide/guidance.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 area is meeting or not meeting the 2010 S02 standard. These documents can be 

found on the EPA'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 proposed in the Federal Register on May 13,2014, would direct state 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 this proposed rule would be used in 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 with these later deadlines 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 intended public health protection. For 

additional information regarding designations for the 2010 S02 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, 

~-rG /~L--

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, COURT-ORDERED DEADLINE* 

Milestone Date** 

Court Order March 2, 2015 

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 22,2016, 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 

modifications and initiates 30-day public 

comment period 

End of 30-day public comment period of 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 July 2, 2016 

designations (no later than 16 months from 

Court Order) .. * The court's order directs the EPA to promulgate additional rounds of designatiOns by 

December 31, 2017, and by December 31 , 2020. 

** o/a = on or about