Enclosure 

EPA Response to Petition for Reconsideration from 

Gas Processors Association and Texas Pipeline Association 

On July 20, 2012, the Gas Processors Association and Texas Pipeline Association petitioned the EPA to 

reconsider the final area designation for Wise County in the Dallas-Fort Worth (DFW) area. For the 

reasons discussed below, the EPA is denying the Petition. For the sake of clarity, we have organized this 

response according to the structure of the July 20, 2012 petition. 

I. Emissions Trends and Inventories 

Issue: The Petition states that the EPA should consider more fully emissions trends and inventories. The 

Petitioner also claims that a new study by Texas Commission on Environmental Quality (TCEQ) 

indicates that volatile organic compounds (VOC) emissions from condensate storage tanks are likely 

much lower than reflected in the emissions estimates that the EPA used. 

Response: This issue was raised during the comment period, and we responded to these comments in 

our Response to Comment (RTC). Thus it is not an appropriate basis for reconsideration. We did not 

look at future trends, such as future reductions that may result from new air regulations, in this 

designation process because that is not an appropriate consideration under the Clean Air Act. See RTC 

at page 58 (“[w]e agree that we did not consider the impact of new air regulations. The implementation 

of new and existing regulations should result in lower ozone precursor emissions in the future; however, 

for purposes of designating areas, we consider whether such areas are “currently contributing” (i.e., 

current activities) to violations of the 2008 ozone National Ambient Air Quality Standards (NAAQS) 

and do not assess or predict future source emissions”). Our evaluation found that Wise County is 

currently contributing to violations of the 2008 ozone NAAQS. 

To clarify, we do consider past trends such as growth rates and patterns.1

 As an example, we state in the 

final DFW Technical Support Document (TSD) that “[r]apid growth in population or vehicle miles 

traveled (VMT) in a county on the urban perimeter signifies increasing integration with the core urban 

area, and indicates that it may be appropriate to include such perimeter area(s) as part of the 

nonattainment area” See TSD page 9. This information is helpful in the five factor analysis to determine 

if an area is contributing to a violation. 

With regards to condensate emissions, we considered the most recent data available at the time that we 

issued the designations. We considered potential overestimation of emissions from condensate storage 

tanks in Texas in the context of concerns raised by Matagorda County officials in March/April 2012. At 

that time, TCEQ indicated to the EPA they were conducting a further study that would be available in 

draft form in Fall 2012.2

 In October 2012, TCEQ provided the EPA with a report on condensate tank 

emission estimates but that report has not yet been finalized. This new technical information is not an 

appropriate basis for reconsideration. As noted by the Court in Catawba v. EPA, 571 F.3d 20 at 23, 

“Congress imposed deadlines on the EPA and thus clearly envisioned an end to the designation process.” 

We do not agree that information that was not available in time for the EPA to consider while complying 

 

1 See “Factors EPA Plans to Consider in Determining Nonattainment Boundaries in Designations for the 2008 Ozone 

NAAQS”, Attachment 2 to the December 4, 2008, EPA memorandum “Area Designations for the 2008 Revised Ozone 

National Ambient Air Quality Standards” from Robert J. Meyers, Principal Deputy Assistant Administrator to Regional 

Administrators, Regions I-X.

2

 Final HGB TSD, pages 6-7. 
with the procedural requirements of the Clean Air Act (Act or CAA) provides an appropriate basis for 

reconsidering the designations. It is important that states are able to rely on the completed designations 

and to move forward with the planning now required for the area. 

Finally, we note, as discussed in the TSD, the DFW area is nitrogen oxide (NOx) limited; thus we 

believe it is unlikely that changes in the VOC inventory would affect EPA’s determination that that 

Wise County emissions contribute to nonattainment. 

II. Adequacy of Record 

Issue: The Petitioner states that generally Wise County is indistinguishable from Hood County, which 

was excluded from the nonattainment area, and that the rationale for excluding Hood County should also 

apply to Wise County. 

Response: As documented in the final DFW TSD, Wise County is distinguishable from Hood County in 

several ways. The 2008 Emissions Inventory (EI) with revisions submitted by Texas in October 2011 

shows that Wise County has approximately twice the amount of NOx and VOC emissions. Wise 

County’s emissions are 11,911 tpy NOx and 17,609 tpy VOC. Hood County’s emissions are 5,515 tpy 

NOx and 8,739 tons per year (tpy) VOC. TSD at 7. Additionally, Hood County is further from violating 

monitors than Wise County (figure 1, page 3). We also summarized the EPA’s evaluation of the Source 

Apportionment Modeling (SAM) that indicated significant differences between contributions to ozone 

from Hood and Wise County in terms of both the maximum impact at a violating monitor (2008-2010 

Design Value (DV)) and the number days with impacts greater than 0.75 ppb (parts per billion). See

TSD at pages 6 – 14 and RTC pages 51 - 61. 

III. Response To Comments 

Issue: Petitioner claims that the EPA did not respond to all significant comments, particularly the 

detailed examples of inconsistencies provided by them in their comment letter dated February 2, 2012. 

Response: While we did not provide responses to certain comments raised during the comment period, 

and as referenced in your Petition, we do not believe this supports reconsideration. As provided below, 

as to the technical concerns raised, our record supports and fully explains our decision. Furthermore, 

certain of these concerns did not address whether the EPA’s five factor analysis for the identified areas 

resulted in disparate treatment, but instead made comparisons between counties in other nonattainment 

areas and the three Texas Counties (Wise, Hood, and Matagorda Counties) only with regard to one or 

two factors out of the five factors the EPA analyzed. Comparing counties from different areas based 

only on one or two of the factors from the five-factor analyses is not sufficient to support a disparate 

treatment argument. See Catawba County, North Carolina v. EPA, 571 F.3d 20 (D.C. Cir. 2009) 

(“petitioners seize upon discrete data points and ignore the very nature of the nine-factor test, which is 

designed to analyze a wide variety of data on a ‘case-by-case basis.’”) 

We also note that unlike most other rulemaking actions under the CAA, Congress did not provide a 

participatory role for parties other than the states and tribes. For designations, section 107(d) of the CAA 

sets forth a detailed and specific process between the EPA and the states. This provision provides: (i) 

that Governors of states make the initial recommendations to the EPA for designations and boundaries; 

and (ii) that the EPA provide the states with 120 days notice of any intended modifications to the state 

recommendation prior to finalizing the designation. The 120 day notification process is for the purpose 

of providing “such State with an opportunity to demonstrate why any proposed modification is 
inappropriate.” The CAA does not expressly provide a role for any other entity (including local 

governments) and, moreover, expressly waives the notice and public comment process of the 

Administrative Procedure Act for initial designations for new or revised NAAQS. Although no public 

comment period is required, the EPA opted to provide such a comment period for the 2012 ozone 

designations. 

Specific issues raised by the Petitioner are identified below. We note that a number of the comments 

raised issues about the differences between the way Wise, Matagorda and Hood Counties were treated. 

In the final designations, the EPA designated Hood and Matagorda Counties as attainment and the 

present Petition raises issues solely with regard to Wise County. Thus, we summarize the issues and 

present our responses below only with regard to Wise County. 

Issue: Petitioner claims that there is no correlation between increased Barnett Shale exploration and 

production and increased ozone. The data illustrate that even with increased production, ozone design 

values are generally down. 

Response: This comment was raised during the comment period. While we did not specifically respond 

to this comment for the DFW area, the comment was considered by the EPA. Thus it is not appropriate 

for reconsideration. The central issue is whether emissions from Wise County contribute to ozone 

violations in nearby areas. As the record indicates, monitors in the Dallas CSA are violating the ozone 

standard and the EPA is required to designate areas as nonattainment if they violate the standard or 

contribute to a violation in a nearby area. As discussed in the RTC and TSD, some of the highest days 

during the 2006-2010 period included transport of Wise County emissions (including any Barnett Shalerelated emissions) to some of the highest ozone exceedances at the Eagle Mountain Lake and Keller 

monitors, which are two of the DFW area’s monitors with the highest ozone levels. The TCEQ’s SAM 

also shows that emissions from Wise County (which would include Barnett Shale-related emissions) are 

transported to the violating monitors and that the amount of contribution could be as high as 50% of the 

total impact on certain days with high ozone levels.3

 

Design values and design value trends are a product of a number of variables, not simply the emissions 

of one or more types of emissions sources, which is why we perform a five-factor analysis in 

determining whether an area contributes to a violation of the standard in a nearby area. Decreases in 

design values over time can occur due to many variables, including decreases in ozone precursor 

emissions (such as in the DFW Nonattainment area due to federal measures and measures implemented 

by TCEQ in past ozone attainment demonstration SIPs). The fact that the design value is lower (i.e., that 

ozone has not “increased”) does not preclude a determination that emissions from Wise County 

contribute to exceedances at violating monitors in the DFW CSA. 

Issue: Petitioner claims that TCEQ has demonstrated through complex modeling that it is NOx, not manmade VOCs that drive ozone formation in the DFW area and the DFW nonattainment area (NAA) is 

generally NOx limited. Emissions from the Barnett Shale are primarily VOCs and further the VOC 

species emitted by oil and gas industry are primarily straight alkanes, and not the highly reactive alkenes 

that are linked to ozone formation. 

Response: As discussed in a previous response, we recognize in the TSD and RTC that the DFW Area is 

NOx limited and that reductions in man-made VOC emissions only have small effects on ozone levels in 

 

3 See the TCEQ source apportionment modeling files, including the Excel Spreadsheet that was placed in the record during 

the final action. (Hood-Wise_DVf_Contribution_wPies.xls)
the DFW area. We also recognized that VOC emissions from Barnett Shale activities are predominantly 

in the form of VOCs that have low reactivity, but would not classify them as non-reactive.4

 However, 

contrary to the Petitioner’s assertion, and as documented in our emissions analysis in the preliminary 

and final TSDs and in TCEQ’s SAM, oil and gas production activity in Wise County does result in 

significant NOx emissions. It is primarily these NOx emissions that supported our determination that 

Wise County emissions contribute to ozone formation in the DFW area. 

Issue: Petitioner claims that wind rose charts demonstrate that, on a yearly basis, the winds rarely blow 

into the DFW area from Wise County. The TCEQ’s findings based on the HYSPLIT model with their 

endpoint analysis, demonstrate that “at most 2.87% of the trajectory endpoints from Wise County impact 

violating monitors.” 

Response: Our response below on the HYSPLIT section of this enclosure address the concern about the 

trajectory endpoints, and also discuss why HYSPLIT modeling can be a more useful tool than 

annualized wind patterns especially in an area like DFW that experiences light wind speeds and winds 

from variable directions. While the percentage of days when the wind carried air from Wise County was 

relatively low overall, our analysis indicated that the days when the air did come from Wise County, the 

downwind monitors had some of the highest ozone readings during the time period evaluated. 

Issue: Petitioner claims that other EPA Regions have declined nonattainment designations based simply 

on prevailing winds. For example, TSDs from various Regions make generalized references to 

prevailing wind patterns, 30-year wind history, wind roses showing yearly average wind direction, and 

references to “predominant” wind direction. 

Response: These comments did not address whether the EPA’s five factor analysis for the identified 

areas resulted in disparate treatment, but instead focused only on meteorology. Therefore, this does not 

warrant reconsideration on this issue. As we have explained earlier, the designation process involves a 

five factor analysis conducted for each individual area. We cannot look at just one or two factors in 

isolation to conclude there has been disparate or inconsistent treatment. Many of the specific issues 

raised by the Petitioner, and discussed below, focus on only one or two factors, without a full 

comparison of how the five factors were applied. EPA will not repeat this full explanation in each 

instance, but it applies throughout this response. 

Issue: Petitioner’s comments include a list of 13 counties in other areas of the country that were 

designated as attainment/unclassifiable. Petitioners claim that these counties are upwind of 

nonattainment counties and violating monitors over 20% of the time. Petitioner asserts that Wise, 

Hood, and Matagorda Counties would not be included in a nonattainment area if another EPA region 

had made the decision. 

Response: Petitioner’s comments identify only the percentage of time a county is upwind and they do 

not address how this information, when considered as part of a more comprehensive five factor 

analysis suggests that EPA treated Wise County in a manner inconsistent with the way we treated 

other areas. Therefore, this does not warrant reconsideration on this issue. 

Issue: The Petitioner indicates that the EPA Region 6 incorrectly and conclusively relied on HYSPLIT 

modeling and used it in a selective manner, while another Region correctly disregarded HYSPLIT 

modeling (e.g., EPA Region 3 in the TSD for the Pittsburgh area) and based meteorological 

 

4 DFW Final TSD, pages 6-8; Houston Final TSD, pages 5-7; RTC pages 52-56.
analyses on general historical wind patterns. The Petitioner further indicates that the EPA failed to 

provide record support adequately justifying its conclusion that HYSPLIT modeling is a proper basis for 

a nonattainment designation in Wise County. The Petitioner indicated that the EPA Region 6 conducted 

a ‘nit-picking’ analysis by focusing on only the days with violations with HYSPLIT instead of using 

general wind patterns as have been used in other preliminary TSDs. The Petitioner listed preliminary 

TSDs for the areas that did not use HYSPLIT to indicate disparate treatment of wind patterns by Region 

6 in Texas. 

Response: We refer generally to our responses addressing the use of the HYSPLIT modeling for the 

DFW area. Wise County was not treated disparately by the EPA’s use of HYSPLIT modeling results. 

HYSPLIT was used in 16 areas where it was either submitted to the EPA or the EPA performed the 

modeling because we believed it could provide additional insight into the factors that contribute to 

nonattainment. 5 For example, we explained in our TSD that HYSPLIT modeling is particularly useful 

for areas, such as Dallas, where wind speeds can be light and wind direction variable. 

Each of our designations decisions were based on a five-factor analysis of the unique circumstances 

relevant to each area. The level of detail for meteorological analysis can vary area-to-area. For example, 

in cases where counties did not have significant emissions compared to other counties in a specific area 

a more general meteorological approach may have been sufficient. 

With regard to the claim that Region 3 disregarded HYSPLIT modeling, this is an incorrect 

characterization. In the preliminary TSD for Pennsylvania, the EPA stated that: 

“Further analysis of backward trajectories could prove helpful in resolving the affect of 

meteorology on this area. Pennsylvania’s March 2009 ozone recommendation did contain some 

NOAA HYSPLIT model backward trajectory information, but not for monitors in the Pittsburgh 

area. The supplied information for a monitor in eastern Pennsylvania indicated that HYSPLIT 

24-hour period back trajectories were highly variable based upon the episode in question. 

Therefore, this information was not useful in determining the impact of meteorology on the 

Pittsburgh-New Castle CSA.”6 

EPA only determined that a HYSPLIT run in eastern Pennsylvania was not useful for evaluating the 

Pittsburgh area, which is located in the western portion of the state. Subsequently, as part of the analysis 

for the final designation decision, the EPA Region 3 used the HYSPLIT model to further understand the 

meteorological transport conditions within the region around Pittsburgh and other areas of 

Pennsylvania.7

 

 

5

 The EPA considered HYSPLIT analyses in the following 16 areas for the 2008 ozone designation process: AllentownBethlehem-Easton, PA; Baltimore, MD; Baton Rouge, LA; Charlotte-Rock Hill, NC-SC; Chicago-Naperville, IL-IN-WI; 

Dallas-Fort Worth, TX; Denver-Boulder-Greeley-Ft Collins-Loveland, CO; Houston-Galveston-Brazoria, TX; Knoxville, 

TN; Lancaster, PA; Memphis, TN-MS-AR; Philadelphia-Wilmington-Atlantic City, PA-NJ-MD-DE; Pittsburgh-Beaver 

Valley, PA; Reading, PA; San Luis Obispo (Eastern San Luis Obispo), CA; and Washington, DC-MD-VA. The TSDs for 

ozone designation decisions for each of these areas can be found in the public docket and on the EPA’s ozone designations 

website. Docket No. EPA-HQ-OAR-2008-0476 and http://epa.gov/ozonedesignations/2008standards/tsd.htm.

6

 Pennsylvania Preliminary TSD “Pennsylvania Area Designations for the 2008 Ozone National Ambient Air Quality 

Standards,” December 2011, page 41 (Docket ID No. EPA-HQ-OAR-2008-0476-0237). We note that Pittsburgh is in 

Western Pennsylvania and the March 2009 HYSPLIT analysis included in Pennsylvania’s 2009 recommendation was for an 

ozone episode in Eastern Pennsylvania.

7

 Pennsylvania Final TSD “Pennsylvania Area Designations for the 2008 Ozone National Ambient Air Quality Standards,” 

April 2012, pages 10-13, 24-28, 41-45, and 73-79 (Docket ID No. EPA-HQ-OAR-2008-0476-0632). 
Issue: Petitioner claims that the EPA Region 6 incorrectly and inconsistently applied HYSPLIT to 

justify a nonattainment designation for Wise County. The Petitioner further claims that HYSPLIT 

cannot establish a causal connection between winds in one area and ozone formation in another. 

Response: We agree that HYSPLIT modeling has limits and that its primary use is in showing where air 

has traveled before reaching a certain location at a given time, thus giving an indication of what 

pollution sources may have contributed to the monitored pollution level. As noted throughout the 

designation process, however, the EPA analyzes meteorology, including HYSPLIT where available, as 

one component of the meteorology factor in the five-factor analysis. The EPA indicated in the 

preliminary and Final TSDs for the DFW area that the combination of back trajectories and the close 

proximity of large emissions of ozone precursors to the monitor supported its decision to include Wise 

County. TCEQ’s SAM modeling, which is based on a wide array of information, including meteorology 

and emissions, further confirmed that Wise County emissions yield increased ozone levels at monitors in 

DFW.8

Issue: Petitioner claims that EPA Region 6’s approach to performing HYSPLIT analyses was 

inconsistent. Specifically, Petitioner claims that Region 6’s use of HYSPLIT was inconsistent with 

other regions, as detailed below:

Response: We do note that some of the HYSPLIT analyses were conducted at different times, and the 

EPA used some slightly different approaches for the different HYSPLIT analyses. For example, we 

varied start time for the back trajectories dependent upon when the 8-hour exceedances occurred at the 

monitor being evaluated. To obtain additional insight, we also separated HYSPLIT runs for several 

different hours for some of the monitors that make up the 8-hour exceedance period since the 

exceedance period is made up of 8 consecutive 1-hour ozone readings. We noted our methodologies for 

conducting the HYSPLIT analyses in the TSD and in the individual electronic HYSPLIT output files. 

The meteorological data on which EPA based its HYSPLIT model analysis was available to the public.9 

On December 20, 2011 (76 FR 78872), the EPA published a notice in the Federal Register inviting 

public comment from interested parties other than states and tribes on the letters sent to states with the 

intended designations. The notice provided that any comments should be received on or before 

January 19, 2012, but in response to requests from several parties, including Wise County, the EPA 

extended the public comment period to February 3, 2012. (See 77 FR 2678, January 19, 2012). TPA 

requested a copy of the HYSPLIT data from the EPA on January 17, 2012. The EPA provided a copy of 

the meteorological and ambient monitoring data on January 19 – 24, 2012, and also posted copies of the 

data to the rulemaking docket. 

County 1 - Issue: (Lebanon County, PA) Petitioner claims that Lebanon County was considered as 

part of the Berks County (Reading) Pennsylvania area but was designated attainment even though the 

winds blew from Lebanon County into Berks County 40 percent of the time during the summer, 

which was far more often than prevailing winds blew from Wise County to the violating monitors in 

the DFW area. TPA recognized that Lebanon County had somewhat lower emissions than Wise 

County. 

 

8 Page 13 of TCEQ attachment to Governor Perry’s comment letter dated February 29, 2012. Source apportionment 

modeling files provided by TCEQ to EPA demonstrate that Wise County NOx emission impacts at other DFW monitors 

including Eagle Mountain Lake and Keller monitors is what makes up almost all of the ozone level changes due to Wise 

County emissions. Electronic files are available in the electronic record for the Final designation. (EPA Document ID: EPAHQ-OAR-2008-0476-0633) 

9 The meteorological data on which EPA based its HYSPLIT model analysis was accessible to the public at the NCAR FTP 

site at ftp://arlftp.arlhq.noaa.gov/pub/archives/edas40/.
County 1 - Response: (Lebanon County, PA) The Petitioner only discusses aspects of two factors, 

meteorology and emissions, and did not address how the EPA’s five factor analysis resulted in disparate 

treatment of Wise County. As to the emission factor, the comment recognizes that emissions in Lebanon 

County were low and relies solely on the meteorology factor to suggest that Wise County was treated 

differently than Lebanon County. With regard to the meteorology, we note two things. First, the 40% of 

the time for wind direction from Lebanon County is a summertime predominant wind analysis and not 

specific to days on which the violating monitor was experiencing ozone exceedances. Second, based on 

comments received, the EPA more closely examined the meteorology using HYSPLIT and the analysis 

results were included for this area in the Final PA TSD. The EPA concluded that air flow was primarily 

from the Southerly direction, rather than from the Westerly direction where Lebanon County is located, 

at times when the monitor was recording ozone exceedances. 

County 2 - Issue: (Lawrence County, PA) Petitioner summarized information from the EPA Region 

3’s preliminary TSD that Lawrence County had 8,960 tpy NOx and 3,814 tpy VOC and is located to 

the west and northwest of violating monitors in the Pittsburgh area. Although Region 3 noted that 

winds in the area had strong westerly components, Lawrence County was designated attainment. 

County 2 - Response: (Lawrence County, PA) Petitioner only discusses aspects of two factors, 

meteorology and emissions. This is not sufficient to demonstrate how the EPA’s five factor analysis 

resulted in disparate treatment of Wise County. 

County 3 - Issue: (Kent County, DE) Petitioner summarized information from the EPA Region 3’s 

preliminary TSD that winds during ozone season come predominantly from the southwest. The 

comment also noted that Kent County's ozone design value was 74 ppb; that its NOx and VOC tpy 

figures were 7,667 and 5,381, respectively; that its VMT was 1,565,000; and that its population growth 

was +28 percent; and that the EPA was proposing to designate the county attainment/unclassifiable 

because it is "unlikely to contribute to downwind violations during most of the ozone season." The 

comment concluded that the facts supporting nonattainment designation of Kent County were 

significantly stronger than those supporting the nonattainment designation of Wise County. 

Nonetheless, Region 3 concluded that Kent County should be proposed to be designated 

unclassifiable/attainment. The comment concluded that there is no doubt that under the Region 6 

method of analysis, Kent County would have been designated nonattainment. 

County 3 - Response: Petitioner examined aspects of three of the factors: meteorology based on general 

wind patterns during the ozone season, emissions/emission related data and air quality monitoring data. 

As an initial matter, we note the circumstances regarding Kent County raised complex issues that are 

not relevant for the DFW area. There are only three counties in Delaware. The northernmost county, 

New Castle, is part of the Philadelphia-Camden-Vineland, PA-NJ-MD-DE CSA. Delaware TSD at page 

4. The middle county, Kent is the Dover, DE metropolitan statistical area and the southern county, 

Sussex, is the Seaford micropolitan statistical area. See Delaware TSD at page 18. All three Delaware 

Counties were designated nonattainment as part of the Philadelphia area for the 1997 ozone NAAQS. 

Thus, for purposes of our analysis, we evaluated all counties within the CSA and the two additional 

Delaware Counties that are outside the CSA but were included as part of the Philadelphia nonattainment 

area for the 1997 ozone NAAQS. In addition, we also evaluated several counties in New Jersey that are 

also outside the CSA but that were included as part of the designated nonattainment area for the 1997 

ozone NAAQS. See Delaware TSD at pages 6 & 18. 
The five-factor analysis for the counties being considered for inclusion in one nonattainment area will 

always be different than a five-factor analysis for the counties being considered for inclusion in another 

area. This is because the facts vary significantly among the areas. For example, the number of counties 

being considered can vary from one to more than 40. Additionally, the geographic extent of an area 

under consideration can vary greatly as well, with some CSAs being as large as 100 or more miles from 

north to south or east to west or both and some being significantly smaller. For that reason, it is difficult 

to draw direct comparisons between two counties in different CSAs with regard to one factor, such as 

absolute emissions. As noted above, one distinguishing factor between Kent County and Wise County is 

that Kent County is not part of the Philadelphia CSA while Wise County is part of the DFW CSA. We 

also identify some differences between Kent County and Wise County below with regard to two of the 

factors raised in the comment. We emphasize, however, that we do not consider this information 

conclusive outside the five factor analysis. We present it simply to rebut the comment suggesting that 

two areas are similar. We evaluated both Wise and Kent Counties based on whether their emissions 

were contributing to a nearby violation of a monitor, not on whether there was a monitor violating the 

standard in the county. We note that the distance to the closest violating monitor is 20 miles for Kent 

County and 0.5 miles for Wise County. See final DFW TSD at page 3 and final Delaware TSD at page 

4. 

With regard to meteorology, based on comments on the adequacy of general surface wind roses, the 

EPA conducted HYSPLIT analysis to further examine meteorology. The more detailed HYSPLIT 

analysis indicated a wider range of wind directions for transport to exceedances in the PhiladelphiaWilmington-Atlantic City PA-NJ-DE-MD nonattainment area. The HYSPLIT analysis also showed that 

the winds are mostly from the south to northwest directions, with the strongest direction being from the 

southwest during monitored ozone exceedances from 2007-2011. See Delaware TSD at pages 13-17. 

With regard to emissions, out of the 19 counties evaluated in the Philadelphia area, Kent County ranked 

14 for NOx and 17 for VOCs. Kent County ranks 14 out of 19 in VMT. While Kent County did have the 

highest growth rate of the counties considered, it has a relatively small population base and it had a low 

proportion of commuters from the county to the Philadelphia area. In comparison, Wise County’s total 

emissions of NOx and VOC are 11,911 tpy and 17,609 tpy, respectively. Wise County ranks 6 out of 19 

counties in the Dallas CSA for NOx emissions and 4 out of 19 for VOC emissions. Population and VMT 

rankings are similar between Wise County and Kent County. See final DFW TSD, pages 6-14. 

County 4 - Issue: (Roane County, TN) Petitioner summarized information from the EPA Region 4’s 

preliminary TSD that Roane County had emissions of 10,711 tpy NOx and 3,006 tpy VOC and was 

predominately upwind of nearby violating monitors. 

County 4 - Response: (Roane County, TN) Petitioner only examined aspects of two factors, 

meteorology and emissions. This is not sufficient to demonstrate how the EPA’s five factor analysis 

resulted in disparate treatment of Wise County. 

County 5 - Issue: (Pointe Coupee Parish, LA) Petitioner also claimed disparate treatment with regard 

to Pointe Coupee Parish, which was considered for inclusion in the Baton Rouge nonattainment area. 

TPA notes that Pointe Coupee Parish's NOx and VOC emissions tpy figures were 15,733 and 2,560 

respectively and that its NOx emissions are higher than those for Wise County. Petitioner also notes that 

Pointe Coupee Parish's population density was roughly equivalent with that of Wise County. Petitioner 

points out that Region 6 stated that "for the five-year 2006-2010 time period only 5 percent of all days 

with ozone concentrations greater than 75 ppb at the LSU site had wind back trajectories that went back 

through Pointe Coupee Parish." The EPA Region 6 proposed a nonattainment determination for Wise 
County even though the winds blew across Wise County toward violating monitors far less often than 

the "only 5 percent" figure upon which Region 6 based its proposed attainment/unclassifiable 

designation for Pointe Coupee Parish in Louisiana. 

County 5 - Response: (Pointe Coupee Parish, LA) Petitioner examined aspects of three factors, 

meteorology, air quality and emissions. In the Final Louisiana TSD, we indicated that the Big Cajun 

Power Plant (which we noted in our preliminary TSD is already controlled) emitted 12,119 tpy in 

2008 and the rest of the Parish’s emissions of man-made NOx were only 3,614 tpy. Furthermore, we 

indicated that for the 5 years of back trajectories for ozone exceedances at the LSU monitor only two 

back trajectories passed over Pointe Coupee Parish. Of the two back trajectories, one of the back 

trajectories barely went through the southwest corner of Pointe Coupee Parish on the opposite corner 

of the Parish from the Big Cajun Power plant in the northeast portion of the Parish. Therefore, it is 

unlikely that emissions from the main point source in Pointe Coupee Parish contributed to the 

violating monitor for this ozone exceedance, leaving only one back trajectory in 5 years that indicates 

potential contribution. In comparison, 7 trajectories in 5 years for the Eagle Mountain Lake monitor in 

DFW passed through areas with emissions in Wise County, and five of these days were the highest 

monitored ozone days that helped set the monitor’s DV. We note in the RTC (page 56) that we 

weighed the combination of emissions and distance to a violating monitor in our evaluation comparing 

Hood and Wise and put more weight on contribution from Wise County due to Wise County’s larger 

emissions and closer proximity to a violating monitor. Similarly, the distance to the only Baton Rouge 

area violating monitor (2008-2010 DV of 78 ppb) is approximately 18 miles for Pointe Coupee Parish

(26 miles from Big Cajun) in comparison to Wise County’s distance of 0.5 miles to the Eagle Mountain 

Lake monitor (2008-2010 DV of 85 ppb). 

County 6 - Issue: (Dutchess, Putnam, Orange, and Ulster Counties, NY) Petitioner compared Wise 

County with Dutchess, Putnam, Orange and Ulster Counties, which are in the New York – New Jersey 

– Long Island, NY-NJ-CT nonattainment area. Petitioner pointed out that the EPA Region 2’s 

preliminary TSD indicated that Dutchess County was upwind 23 percent during the summer; Putnam 

County 24 percent; Ulster County 29 percent; and Orange County 25 percent. 

County 6 - Response: Petitioner only examined meteorology and did not address how the EPA’s five 

factor analysis resulted in disparate treatment of Wise County. 

County 7-Issue: (Stafford County, VA) Petitioner also cited Stafford County Virginia, which the EPA 

evaluated for inclusion as part of the Washington, DC-MD-VA nonattainment area. Specifically, 

Petitioner pointed to the EPA Region 3’s preliminary TSD for Maryland that indicated Stafford County 

is upwind 22 percent of the time and that Stafford County should be designated 

attainment/unclassifiable. 

County 7 - Response: Petitioner generally discussed aspects of only two factors – meteorology and 

emissions, and did not address how the EPA’s five factor analysis resulted in disparate treatment of 

Wise County. 

County 8 - Issue: (Cattaraugus Reservation – Seneca Nation) Petitioner cites meteorological and 

emissions data from the EPA Region 2’s preliminary TSD that indicates that the Cattaraugus 

Reservation could have a small impact on the Jamestown, NY nonattainment area. However, the EPA 

proposed that the Reservation should be designated attainment/unclassifiable.
County 8 - Response: (Cattaraugus Reservation – Seneca Nation) In determining whether a county 

should be included as part of the designated nonattainment area, we look at whether the county 

contributes to nonattainment in the area. Our analysis looks at whether the area’s contribution is at a 

level to have a significant effect on ambient ozone levels. See Catawba v. EPA at 39 (recognizing that 

“contribute” under section 107(d) is ambiguous and does not necessarily mean any level of 

contribution.) In looking at our 5 factors, we note that in the Jamestown Area TSD that there were no 

known permitted sources on the Reservation and that the population was sparse. We also noted that 

the Reservation is downwind of Jamestown and transport to the nonattainment area is likely to be low 

or nonexistent. Based on our full analysis of all of the factors, we concluded that tribal lands are not 

contributing to the nonattainment area. Jamestown TSD at 4, 9, 12.

County 9 - Issue: (Sussex County, DE; Berks County, PA; Calvert, Fredrick, Montgomery, Prince 

George’s and Loudon Counties, Washington DC-MD-VA) Petitioner summarized information from 

several of the EPA Region 3’s preliminary TSDs regarding counties that the EPA proposed to 

designate as nonattainment and claimed that they show disparate treatment for Wise County.10

County 9 - Response: The issue for each of these counties was not whether the area should be 

designated as nonattainment but rather in which nonattainment area the county should be included. 

We note that each of these counties is located in the northeast U.S. corridor where nonattainment 

areas frequently adjoin, and the associated CSA and CBSA can include 40 or more counties. Our 

consideration of which nonattainment area a county should be affiliated raises different issues than the 

issue of whether an area should be designated nonattainment based on contribution. For example, the 

jurisdictional factor often plays a more significant role in these cases and, in the absence of a fivefactor analysis supporting a contrary conclusion, we generally will defer to the state's 

recommendation as to which of the two nonattainment areas should include the county. See e.g., 

Pennsylvania Department of Environmental Protection v. EPA, 429 F.3d 1125, 1129 (D.C. Cir. 2005). 

Our decisions for these counties do not show disparate treatment for Wise. 

County 10 - Issue: (Dauphin and York Counties, PA) Petitioner generally referred to discussion of the 

EPA’s meteorology factor in the EPA Region 3’s preliminary TSD. The EPA proposed to designate 

these counties attainment/unclassifiable even though meteorology indicates that Lebanon and Dauphin 

may contribute to violations in Lancaster.

County 10 - Response: (Dauphin and York Counties, PA) Petitioner only discussed one factor, 

meteorology, and did not address how the EPA’s five factor analysis resulted in disparate treatment of 

Wise County. 

County 11 - Issue: (Dorchester, Wicomico, and Worcester Counties, MD) Petitioner generally referred 

to the EPA’s emissions and meteorology factors discussion in the EPA Region 3’s preliminary TSD.

The EPA proposed to designate three Maryland counties attainment/unclassifiable even though 

emissions from these counties would contribute little to violations in downwind Sussex County, 

Delaware.

 

10 These counties are: (1) Sussex County, Delaware, which was designated as a single county nonattainment area and not 

included as part of the Philadelphia nonattainment area; (2) Berks County, Pennsylvania, which was designated as a single 

county nonattainment area and not included as part of the Philadelphia nonattainment area; and (3) Calvert, Fredrick, 

Montgomery, Prince George’s and Loudon Counties which were included in the Washington DC-MD-VA nonattainment 

area and not the Baltimore nonattainment area.
County 11 - Response: (Dorchester, Wicomico, and Worcester Counties, MD) After a review of the 

EPA’s five factors, the EPA concluded in the Final TSD “[a]lthough emissions from those counties 

might contribute to violations in downwind Sussex County, Delaware, the emissions levels from those 

counties are so low that little actual contribution is expected.” The EPA determined after weighing all 

five factors that these counties do not in fact contribute to ozone at a violating monitor.

County 12 - Issue: (Carroll and Hall Counties, GA) Petitioner generally discussed distances separating 

emissions sources from the violating monitors. The EPA Region 4’s preliminary TSD proposed a 

designation of attainment/unclassifiable for these counties because their distance from violating 

monitors limited their impact on such violating monitors.

County 12 - Response: Petitioner only discussed one aspect relating to ambient air and distance to a 

violating monitor, and thus did not address how the EPA’s five factor analysis resulted in disparate 

treatment of Wise County. 

Issue: Petitioner (on page 20 of their comment letter) indicated that TCEQ has already determined, in a 

study done in connection with the East Texas Combustion rule, that the imposition of controls on 

sources in six counties, including Wise and Hood, would have such a negligible effect on conditions 

in the DFW nonattainment area; therefore, the Combustion rule was not justified. Modeling 

sensitivity runs were conducted by TCEQ in connection with the East Texas Combustion rule in 

order to assess the potential benefit of including six counties, including Wise and Hood, in the rule. 

According to TCEQ, "[t]hese sensitivity runs indicate that the Dallas-Fort Worth eight-hour ozone 

nonattainment area would only benefit approximately 0.05 ppb reduction in ozone from including 

these six counties under the rule." See 32 Texas Register 3303 (June 8, 2007). 

Response: Section 107(d) of the CAA requires the EPA to designate as nonattainment any area that does 

not meet the air quality standard or that contributes to a violation of the air quality standard in a nearby 

area. Based on our analysis of contribution in the DFW TSD, we determined that Wise County 

contributed to monitored violations of the 2008 ozone NAAQS and included Wise County in the ozone 

nonattainment area. We further note here, that in evaluating whether an area is contributing to a current 

violation of the ozone NAAQS, we do not evaluate how the implementation of individual, specific 

measures, or the failure to implement such measures, might affect ozone levels within the area. The 

issue of which measures are appropriate for reducing ozone levels in an area violating the standard will 

be addressed by the states during the post-designation attainment planning process. 

We also note that the modeling the Petitioner cites was in relation to an older ozone standard (85 ppb 

versus the current 75 ppb) and is comprised of an older meteorological episode with fewer days. 

Additionally, the emission estimates in the modeling do not account for the growth in emissions due to 

the Oil and Gas developments in north Texas since 2005/6. The modeling Petitioner discussed is older 

modeling that was for an older limited number of days episode (10 days) that did not have as many 

meteorological regimes as the more recent SAM modeling provided by TCEQ (with over 30 days) to the 

EPA as part of their comments for the designations of the 2007 8-hour standard. The older modeling 

only was conducted for evaluations of potential controls to help the DFW area attain the 1997 8-hour 

standard (85 ppb) and the conclusions would likely be different if the analysis was done for the current 

75 ppb standard. The modeling and associated emission inventory cited by the Petitioner did not include 

revised emissions reflecting the growth of oil and gas emissions in Wise County and other North Texas 

counties since 2005/6. Since that time, these counties have seen increased emissions due to oil and gas 

field developments. 
IV. Analysis of HYSPLIT and Potential Impact of Wise County Emissions 

 

Issue: The Petitioner claims that the EPA’s HYSPLIT analysis was not conclusive and given undue 

weight. Specifically, the Petition claims that the HYSPLIT modeling gives only an indication of possible 

contribution to downwind nonattainment. Further, Petitioner claims that the EPA should provide greater 

clarity as to how HYSPLIT is applied and what weight HYSPLIT results are given in making the Wise 

County designation decision. 

Response: Petitioner raised the HYSPLIT issue during the comment period and the EPA responded to 

those comments. See RTC pages 59, 60. Therefore, reconsideration is not appropriate. Our record fully 

supports our decision. The EPA’s record explains that HYSPLIT is a useful tool for determining areas 

where air originates or passes through on the way to a monitored ozone exceedance. As we stated in the 

RTC, “[i]n terms of identifying potential local and regional source-receptor patterns, HYPLIT wind 

trajectory or other modeling based tools are excellent tools for determining the frequencies for which 

areas potentially contribute to high ozone levels and are preferred over more basic assessments of wind 

speed and direction at a given point locations (e.g., wind roses, or pollution roses). The basic 

assessments, such as wind roses, are potentially misleading in cases where wind speeds are light and the 

wind direction is variable. . .”11 The light and variable meteorological regime is one of the classic 

meteorological types that results in high ozone in the DFW area. 

We conducted HYSPLIT analysis for several monitors in DFW for purposes of both the Preliminary 

TSD (December 2011) and the Final TSD (April 2012). In the Final TSD, we noted that “[t]he 

HYSPLIT model yields an estimate of the path an air mass has traveled before reaching a monitor at a 

specific location and time. Specifically, the model provides the centerline of the probable path. By 

knowing where an air mass has traveled before reaching a monitor where an exceedance has occurred, 

one can consider what potential areas and emission sources could have contributed to the exceedance.” 

In the Final TSD at page 14, we stated, “[w]e focused on the Keller and Eagle Mountain Lake monitors 

in Tarrant County and the Parker County monitor because the Keller and Eagle Mountain Lake monitors 

have recorded some of the highest ozone levels in the region, and inclusion of the Parker County 

monitor provided a good cross-section of the monitors in the western DFW area that experienced 

exceedances in the 2006-2010 period.” The EPA included trajectory plot maps for the Keller and Eagle 

Mountain Lake monitors in both the Preliminary and Final TSDs and also made the individual back 

trajectory files available for review during the comment period. Analysis of the plots in the TSDs 

indicates that 3 trajectory ‘centerlines’ directly traversed Wise County for the Keller monitor, and at 

least 7 trajectory ‘centerlines’ traversed Wise County for the Eagle Mountain Lake monitor. In addition, 

some other back trajectories that did not directly traverse Wise County had centerlines near enough to 

Wise County to suggest a path of upwind influence involving Wise County emissions. Accordingly, we 

concluded that there are a number of days (not just two) with back trajectories that suggest influence 

from Wise County emissions. 

 

As provided in the Final DFW TSD, a review of the individual trajectory files shows that several of the 

days that trajectories passed through Wise County were also days that made up the 1st to 4th highest 

monitored values, which are the values used in establishing the design value at the Eagle Mountain Lake 

and Keller monitors during the periods evaluated. In fact, five of the seven back trajectories that 

traversed Wise County occurred on days that contributed the Eagle Mountain Lake Design value 

 

11 See page 59 of the RTC. 
calculation.12 The individual trajectory files were included in the supporting materials for the EPA’s 

intended and final designations. 

V. Source Apportionment Modeling (SAM) and Opportunity for Public Comment: 

Issue: The Petitioner claims that the EPA did not provide opportunity for public comments on the use of 

TCEQ’s SAM modeling. Specifically, the Petition claims that the EPA did not present any source 

apportionment modeling in its proposed designation decision, yet relied on such modeling in making the 

final designation decision for Wise County. 

Response: While we agree that our analysis of the state’s SAM modeling was not available for comment 

at the time of proposal, we do not believe this issue warrants reconsideration. First, in response to the 

EPA’s 120-day letter notifying it of the intended designations, the state submitted, among other things, 

the SAM data and results. Our evaluation of the SAM was in response to such submittal and was 

consistent with the process established by Congress in section 107(d) of the Act. For initial area 

designations for a new or revised NAAQS, section 107(d)(1) of the CAA sets forth a detailed and 

specific process between the EPA and the states. This provision provides: (i) that Governors of states 

make the initial recommendations to the EPA for designations and boundaries; and (ii) that the EPA 

provide the states with 120 days notice of any intended modifications to the state recommendation prior 

to finalizing the designation. The 120-day notification process is for the purpose of providing “such state 

with an opportunity to demonstrate why any proposed modification is inappropriate.” The CAA does not 

expressly provide a role for any other entity and, moreover, expressly waives the notice and public 

comment process of the Administrative Procedure Act for initial designations for new or revised 

NAAQS. See CAA section 107(d)(2)(B). Although no public comment period is required, the EPA 

opted to provide such a comment period for the ozone designations for the 2008 ozone NAAQS. We 

appropriately followed the process specifically contemplated by the Act. The EPA’s response to 

TCEQ’s SAM is detailed in the EPA’s final TSD. See Final DFW TSD at 15-20. 

Second, and as a general matter, agencies are not required to provide an additional opportunity for 

public comment on material supporting a final rule, such as responses to comments or on information 

supporting a response to a comment. Such an approach would result in an unworkable endless 

rulemaking process. See Catawba, 571 F.3d at 50-51 (In rejecting a claim by New York that it should 

have been allowed additional input into the EPA’s decision to rely on a different monitor for evaluating 

contribution for the final designation than it did for the intended designation the court noted that such an 

ongoing exchange with the states is inconsistent with the CAA and that “Congress imposed deadlines on 

EPA and thus clearly envisioned an end to the designation process.”) See also International Fabricare 

Institute v. EPA, 972 F.2d 384, 399 (D.C. Cir. 1992) (notice and comment is not intended to result in 

“interminable back-and-forth”) and Community Nutrition Institute v. Block, 749 F.2d 50, 58 (D.C. Cir. 

1984) (agency is not required to provide additional opportunity to comment on its response to 

comments). 

 

12 We note that all this data is available in the record. For the Eagle Mountain Lake Monitor, the following days were the 1st

thru 4th High values that set the monitor’s DV. Highlighted in BOLD are the days that EPA’s HYSPLIT analysis indicates 

potential contribution from Wise County emissions. 2006 (6/14 – 107 ppb, 6/9 – 106 ppb, 6/28 – 98 ppb, 7/18 – 98 ppb); 

2007 (8/14 – 121 ppb, 8/15 – 101 ppb, 10/04 – 86 ppb, 9/22 – 84 ppb, 7/25 – 84 ppb); 2008 (8/04 – 98 ppb, 6/18 – 92 ppb, 

6/23 – 86 ppb, 6/19 – 85 ppb); 2009 (6/25 – 100 ppb, 6/5 – 92 ppb, 6/26 – 92 ppb, 8/26 – 91 ppb, 7/2 – 91 ppb); 2010 (6/4 – 

94 ppb, 8/27 – 91 ppb, 8/28 – 83 ppb, 5/29 – 81 ppb). When there was a tie for the fourth high value we looked at trajectories 

for both days.
Issue: The Petitioner claims that as part of the final rule the EPA used a new 1% standard in analyzing 

the source apportionment modeling (SAM), and it did not offer a rational basis for its use or opportunity 

for comment. Furthermore, the Petition claims that EPA was inconsistent in our use of the 1% standard 

and specifically raises concerns with the EPA’s review and conclusions of SAM analysis for three 

counties in the Chicago area. 

Response: The EPA considered SAM in its decision making only in areas where it was provided by 

states or others during the public process. Since the SAM was provided during the comment period, as 

discussed above, our evaluation consequently could not be available for public comment. 

SAM results were available for the EPA consideration in the designation process for only three areas, 

Dallas, Houston and Chicago, because those were the only areas where it was developed and submitted 

by states or other entities. The EPA does not have specific guidance on how to evaluate the impact of 

emissions from a county on a nearby violating monitor in the context of a designation decision. 

Moreover, in the few instances where SAM was submitted for our consideration, the form and type of 

the information varied between areas. The EPA evaluated each submission of SAM on a case-by-case 

basis, carefully evaluating a number of issues including how the modeling was conducted, model 

performance, and available data from the analysis in order to determine how to appropriately evaluate 

the results. 

For the SAM submitted for Dallas and Houston, we considered other recent modeling work that could 

serve as a guide. Our basis for identifying days with a non-trivial impacts is discussed on page 17 of the 

TSD where we explained, “Often in attainment demonstration modeling, controlling of sources is 

evaluated and results in only a few tenths of a ppb change, therefore we used a 1% of the standard cut 

point for the days where we would consider Hood or Wise County’s emissions to be significant.” We 

also note that modeling from TCEQ in a 2007 8-hour Ozone Attainment Demonstration for DFW 

included multiple analyses of individual control strategies and the resultant impacts on monitors in DFW 

area, where Texas had chosen controls that provided changes of a few tenths of a ppb. 13 In addition, we 

also note that the EPA concluded in the recent Cross State Air Pollution Rule, that a “one percent of the 

NAAQS” impact result in the source apportionment modeling was appropriate to determine if a state’s 

emissions significantly impacted a downwind state’s nonattainment or maintenance area. 14 Thus we 

believe it was reasonable to examine the frequency of a modeled impact of 0.75 ppb, or one percent of 

the 2008 ozone standard, as a metric to identify days with a nontrivial impact.15 

In addition, the number of days exceeding the one percent (0.75 ppb) cut point is only one of the metrics 

evaluated from the SAM results. In the DFW Final TSD and in supporting files, we discussed all of the 

metrics used in our assessment of the SAM results, and the unique factors that we weighed in our 

analysis of SAM results for DFW. Using the detailed daily information available to the EPA for 

analyzing SAM for the DFW and Houston areas designations, we evaluated the average impact, 

maximum impact, as well as the number of modeled days exceeding 0.75 and 0.70 ppm where the Wise 

County impact was above 0.75 ppb. These other model output metrics also help explain the impact of 

Wise County. For example, on some specific modeled days the impact of Wise County was much larger 

than 0.5 ppb and as much as 5 ppb at the Eagle Mountain Lake Monitor which is one of the monitors in 

 

13 See the sensitivity runs in TCEQ’s 2007 DFW 1997 8-hour ozone Attainment Demonstration SIP - APPENDIX D: DFW 

Future Case (2009) Sensitivity Tests.

14 See Cross State Air Pollution Rule and the Technical Support Document for the rule(Docket ID: EPA-HQ-OAR-2009-

0491 at www.regulations.gov)

15 TSD page 17, TCEQ’s 2007 DFW 1997 8-hour ozone Attainment Demonstration SIP – Appendix D: DFW Future Case 

(2009) Sensitivity Tests.
DFW that sets the DV for the DFW nonattainment area. 16 Also, it is important to remember that the 

SAM results were only piece of information that we considered in our five factor analysis that resulted 

in our determination that Wise County contributes to nonattainment in the DFW area. 

Our decision to use 1 % of the NAAQS or 0.75 ppb, as a cut point to identify days with a non-trivial 

impact is supported by our record and a count of such days is only one of the metrics we evaluated from 

the SAM results. As stated in our TSD, the 2008 Emissions Inventory for Wise County shows that Wise 

County’s nitrogen oxide emissions of 11,911 tpy are the 6th highest of the 19-county DFW Combined 

Statistical Area (CSA) and the County’s volatile organic compound emissions of 17,609 tpy are the 

fourth highest of the 19 counties. See TSD pages 6-7. The TSD demonstrates that there are six ozone 

monitors violating the standard in the two counties adjacent to Wise County (TSD Figure 1, page 3) and 

notes that Wise County is less than 1⁄2 mile from a violating monitor with a design value of 0.085 parts 

per million (TSD 2008 to 2010 data, pages 5 and 23). We also evaluated meteorological transport 

patterns during exceedances using NOAA’s HYSPLIT model. These patterns indicate that emissions 

from Wise County are transported to the DFW ozone monitors violating the standard based on 2008-

2010 data, and we conclude that the Wise County emissions are large enough that they can contribute to 

ozone exceedances on certain days. See TSD pages 14-17, 19, 20, and 23. 

Finally, the Region 6 evaluation of SAM was not inconsistent with actions taken by other Regional 

offices. Again, our record supports our decision on this issue. The EPA considered SAM for the 

Houston area in the same way we considered it for Dallas because the SAM submitted for both areas 

was similar in how it was performed and the type of information provided. The only other area for 

which the EPA had SAM results was for the Chicago area. The SAM submitted for the Chicago area 

was sufficiently different that direct comparisons to the DFW area analysis are not generally 

appropriate. In the Chicago area SAM, the EPA was provided the average modeled impact levels on 

estimated exceedances for an entire ozone season. Emphasis on the average modeled impact is more 

appropriate when a full ozone season of model results is available. A full season of modeling results was 

not available for the DFW area. Indiana had provided SAM modeling that evaluated the impact of three 

Indiana counties on a monitor in the greater Chicago area. The reported impacts from two Counties 

(Lake and Porter) were about 2 ppb and 4 ppb. The SAM result for the third Indiana County (Jasper) 

indicated less than 0.5 ppb impact. In evaluating this result, the EPA was aware that the modeling did 

not reflect reductions that had been achieved at a large power plant in Jasper County, reducing the Jasper 

County total emissions of NOx by more than 50%.17 Based on the analysis of all the factors, including 

the SAM and additional emission reductions, the EPA decided to include Lake and Porter counties, and 

not to include Jasper County, Indiana within the nonattainment area. As with the contribution level 

evaluated for Wise County, the contribution levels discussed in the Region 5 Chicago Final TSD do not 

represent a bright line criterion for inclusion or exclusion of a county. Moreover, the inclusion of two 

counties with an average contribution of 2 and 4 ppb and exclusion of a county with 0.5 ppb in the 

Chicago area is not inconsistent with inclusion of Wise County based in part on a count of days with 

greater than 0.75 ppb contribution in the Dallas area. As noted above, however, for both the Chicago 

and Dallas areas, this consideration was simply one element of one of the five factors the EPA 

considered in determining whether to include counties as part of the designated nonattainment area. 

 

16 TSD page 20 17 Region 5 TSD, Original 2008 NOx emissions quantified as 19,788 tons/year and value was footnoted as “... updated 

emissions data were provided for Jasper County showing 2011 NOx emission levels of 9,791 tons.”
VI. Concern About Treatment of the Oil and Gas Industry 

Issue: The Petitioner claims that the designation of Wise County should be reconsidered because of a 

perceived bias by former Regional Administrator Dr. Armendariz against the oil and gas industry that 

may have played an undue role in the designation process. 

Response: The EPA’s final designation decision for the DFW area was based on the EPA’s evaluation of 

the data and technical information, extensive and thoughtful consideration of input from TCEQ and 

other interested parties. The EPA’s national Office of Air and Radiation works closely with technical 

staff in EPA’s regional offices to ensure that decisions are based on the factual record and are consistent 

across the country. As demonstrated in the TSD accompanying the EPA’s intended designations issued 

in December, 2011 and the TSD accompanying the final designation on April 30, 2012, the EPA 

performed a thorough assessment of information relevant to five designations-related factors in 

determining which areas should be included as part of the DFW nonattainment area. The final decision 

was made by Administrator Lisa Jackson based on the record before the EPA. We further note that there 

are other Texas counties where oil and gas production and activity occur that were initially considered 

for inclusion into a nonattainment area, but were ultimately not included. For example Hood County, 

Texas and Matagorda County, Texas were considered and proposed for inclusion in their respective 

areas. However, following a review of comments from Texas and from public commenters and upon 

further evaluation of all available data relevant to their contribution to ozone violations, we determined 

those counties should not be included as part of a nonattainment area. Our record details those decisions.