State of Wisconsin 

DEPARTMENT OF NATURAL RESOURCES 

September 16, 2015 

Regional Administrator Susan Hedman 

U.S. Environmental Agency- Region V 

77 West Jackson Boulevard 

Mail Code: R-19J 

Chicago, IL 60604-3507 

Scott Walker, Governor 

Cathy Stepp, Secretary 

Telephone 608-266-2621 

Toll Free 1-888-936-7463 

TTY Access via relay - 711 

SUBJECT: Updated Wisconsin Designation Recommendations for the 2010 1-Hour Sulfur Dioxide (S02) 

National Ambient Air Quality Standard (NAAQS) 

Dear Regional Administrator Hedman: 

This letter addresses two groups of areas identified in Janet McCabe's March 20, 2015 letter to Secretary Stepp 

regarding future rounds of area designations for the 2010 1-hour S02 NAAQS. In the letter, and based on 

preliminary data, EPA identified one source (Columbia Energy Center) and one monitor (Green Bay East High in 

Brown County) in Wisconsin as meeting the criteria established in a March 2, 2015 court order. 

The following recommendations and supporting information for EPA to consider when making final 

determinations associated with this first round of designations include: 

• The Columbia Energy Center no longer meets the criteria established by the court order and is not subject 

to the designations timeline established in that order. 

• Modeling conducted by the department and application of the five factors described in EPA's S02 area 

designations guidance indicate that EPA should designate the county in which Columbia Energy Center is 

located (Columbia County) as attainment for the 2010 1-hour S02 NAAQS. 

Additionally, future intentions regarding the Brown County S02 monitor at Green Bay East High School are 

addressed in this letter. 

Columbia Energy Center and Columbia County 

In the March 20, 2015 McCabe letter, EPA proposed that Columbia Energy Center met the criteria established in 

the March 2, 2015 court order. Specifically, EPA's data showed that Columbia Energy Center exceeded a 

threshold of 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. 

Since 2012, several changes affecting S02 emissions from the Columbia Energy Center have occurred. On June 

18, 2013, the facility entered into consent decree 13-cv-266 with EPA and the Sierra Club, which required the 

installation and operation of pollution control equipment and practices that would achieve significant reductions 

of S02, NOx and PM emissions. The consent decree specified that by January 1, 2015, the Columbia Energy 

Center had to continuously operate dry flue gas desulfurization (DFGD) so that units 1 and 2 could achieve and 

maintain a 30-day rolling average emission rate for S02 of no greater than 0.075lbs/MmBtu. The consent decree 

further specified an annual S02 limit of3,286 tons starting in 2015. 

On September 10, 2015, WDNR revised the facility's construction permit (14-POY -17 4-R1, enclosed) to include 

limitations, conditions and other requirements contained in the consent decree, which make the S02 limitations 

and conditions permanent and federally enforceable. Since the facility is currently complying with a permanent 

and enforceable S02 limit below 16,000 tons, and otherwise does not meets the criteria as specified in the March 
2, 2015 court order, the Columbia Energy Center is no longer subject to the July 2, 2016 round of area 

designations established by that order. 

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Based on a technical analysis, including dispersion modeling, completed by the department and provided as an 

enclosure to this letter, and considering subsequent guidance on S02 NAAQS implementation released by EPA, 

WDNR recommends that EPA designate the county in which Columbia Energy Center is located (Columbia 

County) as attainment for the 2010 1-hour S02 NAAQS. EPA's March 20, 2015 S02 area designations guidance 

describes five factors to consider when determining the appropriate attainment boundary when designating areas 

for the S02 NAAQS. WDNR has fully addressed these criteria in support of its recommendation, as follows: 

1. Dispersion modeling results. WDNR modeled Columbia Energy Center's new limits using a dispersion 

modeling protocol based on EPA's December 2013 S02 NAAQS Designations Modeling Technical 

Assistance Document (TAD) and developed collaboratively with the facility and EPA Region 5. The 

results of the modeling (enclosed) show that the Columbia Energy Center will not violate the S02 

NAAQS when complying with its new permanent and enforceable S02 limit. 

2. Emissions-related data. As described in the enclosed analysis, the dispersion modeling conducted for 

Columbia Energy Center included and considered all stationary sources of S02 located within Columbia 

County. 

3. Meteorology. As described in the enclosed analysis, WDNR's modeling included meteorology 

appropriate to the area as described in EPA's Designations Modeling TAD. 

4. Geography and topography. WDNR considered geography and topography when considering both the 

sources to include in the modeling and where to place modeling receptors, taking into account specifically 

the Baraboo Hills area of the county. This is described further in the enclosed analysis. 

5. Jurisdictional boundaries. EPA's S02 area designations guidance describes how county boundaries may 

be appropriate for defining attainment areas in the absence of any other relevant information that would 

help define a more specific boundary around the S02 source in question. WDNR has appropriately 

considered all S02 emissions sources in the county in the enclosed analysis, and the results support 

designating all of Columbia County as attainment. 

Based on the five factor analysis, a designation of attainment for Columbia County, Wisconsin for the 2010 1-

hour S02 NAAQS is supported. WDNR recommends that the EPA designate Columbia County as attainment at 

the earliest possible date, but no later than July 2, 2016. 

Brown County 

The March 20 letter also identified the Green Bay East High air quality monitor (55-009-0005) in Brown County 

as violating the 2010 1-hour S02 NAAQS based on preliminary 2012-2014 data and therefore potentially subject 

to the designations schedule established in the court order. EPA's S02 area designations guidance describes the 

consideration of certified 2015 S02 monitoring data for fmal determinations on designation recommendations. 

WDNR will evaluate the monitor's certified data once the 2015 monitoring season has concluded. If the resulting 

2013-2015 monitored design value does not show a violation of the NAAQS, WDNR intends to recommend that 

EPA designate Brown County, Wisconsin as attainment at the earliest possible date, but no later than July 2, 

2016. 

Further, on April8, 2013, the department recommended that EPA designate forty Wisconsin counties as 

attainment for 2010 1-hour S02 NAAQS, including Brown County. As WDNR conveyed at the time, Brown 

County's monitored design value was below the NAAQS, as had been the case for several years. WDNR believes 
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EPA should have already designated Brown County as attainment based on that information, and requests EPA 

act expediently on any further attainment recommendation WDNR may make for this county in 2016. 

Thank you for considering this information and Wisconsin's recommendations. If you have any questions or 

require additional information, please contact Gail Good, acting Air Director, at Gail.Good@wisconsin.gov or 

608-266-1058. 

Sincerely, 

Bart Sponseller 

Deputy Division Administrator 

Environmental Management Division 

Enclosures 

cc: Cathy Stepp, Secretary 

Mike Bruhn, Assistant Deputy Secretary 

Pat Stevens, Administrator, Environmental Management Division 

Gail Good, Acting Air Director