SIDLEY AUSTIN LLP

1501 K STREET, N.W.

WASHINGTON, D.C. 20005

(202) 736 8000

(202) 736 8711 FAX

BEIJING

BRUSSELS

CHICAGO

DALLAS

FRANKFURT

GENEVA

HONG KONG

HOUSTON

LONDON

LOS ANGELES

NEW YORK

PALO ALTO

SAN FRANCISCO

SHANGHAI

SINGAPORE

SYDNEY

TOKYO

WASHINGTON, D.C.

twebster@sidley.com

(202) 736 8138 FOUNDED 1866

Sidley Austin LLP is a limited liability partnership practicing in affiliation with other Sidley Austin partnerships.

July 20, 2012

VIA FEDERAL EXPRESS AND ELECTRONIC MAIL

Administrator Lisa P. Jackson

Environmental Protection Agency

Room 3000, Ariel Rios Building

1200 Pennsylvania Ave, NW

Washington, DC 20460

(jackson.lisa@epa.gov)

Acting Regional Administrator Samuel Coleman

EPA Region 6 

1445 Ross Avenue, Suite 1200

Dallas, Texas 75202

(coleman.sam@epa.gov)

Kevin McLean

Associate General Counsel for the Air and Radiation Law Office (Acting)

Office of General Counsel (Mail Code 2344A)

Environmental Protection Agency

1200 Pennsylvania Ave NW

Washington, DC 20460

(mclean.kevin@epamail.epa.gov)

RE: Request for Partial Reconsideration and Stay of EPA’s Final Rule titled “Air 

Quality Designations for the 2008 Ozone National Ambient Air Quality Standards,” 

77 Fed. Reg. 30,088 (May 21, 2012) (Docket No. EPA–HQ–OAR–2008–0476), as it 

applies to Wise County, Texas

Dear Administrator Jackson, Regional Administrator Coleman and Associate General Counsel 

McLean:

I am writing on behalf of Devon Energy Corporation (“Devon”) to respectfully request 

that the U.S. Environmental Protection Agency (“EPA”) grant partial reconsideration and 

immediately stay the effective date and implementation of EPA’s Final Rule titled “Air Quality 

Designations for the 2008 Ozone National Ambient Air Quality Standards,” 77 Fed. Reg. 30,088 

(May 21, 2012) (the “Rule”) as it applies to Wise County, Texas. 
2

As discussed below, EPA should reconsider the designation of Wise County as being in 

nonattainment with the 2008 8-hour ozone National Ambient Air Quality Standard (“NAAQS”). 

The Agency’s final decision is not supported by sound science, does not have a rational basis in 

the record, relies on methodologies that are a departure from and not a logical outgrowth of the 

proposal, and is otherwise arbitrary. In brief, reconsideration is warranted for the following 

reasons:

• At the outset, we urge the Agency to reconsider the Wise County, Texas, 

nonattainment designation anew now that EPA has made fundamental changes to 

the leadership of Region 6, which had primary responsibility for the designation 

recommendation. The record demonstrates that former EPA Region 6 

Administrator Dr. Al Armendariz was the decision maker who recommended 

designating Wise County as being in nonattainment. As the Agency is aware, Dr. 

Armendariz resigned just one day prior to EPA Headquarters adopting his 

recommendation in the final Rule. We do not intend this document to be a 

rehashing of the controversy surrounding Dr. Armendariz’s departure. However, 

based on information that became available after the comment period closed, 

along with his publications from before he became Regional Administrator, we 

have serious concerns that Dr. Armendariz did not bring the spirit of pure 

objectivity and lack of bias that is the sought-after hallmark of good government 

and defensible agency action. Given the direct involvement of Dr. Armendariz in 

this decision, his public positions regarding oil and gas development in the 

Barnett Shale generally and in Wise County in particular, and the fact that Dr. 

Armendariz’s views regarding the treatment of the oil and gas industry were not 

fully disclosed during the comment period, we urge EPA to reconsider and stay 

the Wise County decision so that the Agency can make a decision free from any 

shadow of bias. Should EPA grant reconsideration, Devon commits to support 

EPA’s and the Region’s efforts on reconsideration as a key stakeholder in any 

public comment period and in assisting the Agency in its analysis in any other 

appropriate manner. 

• Against the Region 6 decision making environment background that existed as the 

Wise County matter was being considered, there are very significant additional 

reasons that EPA must grant reconsideration here. First, EPA in the final Rule 

for the first time supported its decision in part with a faulty re-analysis of 

modeling submitted by TCEQ. This newly-released, and flawed, analysis relies 

on a heretofore undisclosed 1% standard for what the Region considers to be a 

contribution to ambient air quality, a standard which the Agency does not use in 

other Regions. In the only other Region where EPA arguably comes close to 

using a similar methodology, that Region applies a significantly distinct standard 

that sets a threshold for contributions up to two and a half times higher than EPA 

applied for Wise County. Additionally, in calculating and applying this standard, 

EPA relies on modeling that is inconsistent with its past practice and guidance 

documents. This disparate treatment leads to an arbitrary decision for Wise 

County that would have been different in any other EPA Region, and EPA’s new 

faulty analysis—which was not part of the proposed rule and public comment 

process—warrants reconsideration.
3

• Second, EPA Region 6, in a departure from other EPA Regions, relied 

inappropriately on a model known as HYSPLIT to justify the ozone 

nonattainment designation for Wise County. However, as other EPA Regions 

have recognized, HYSPLIT cannot establish a causal connection between winds 

in one area and ozone formation in another—a critical link in the decision on 

whether an area is contributing to nonattainment. In numerous separate instances 

involving other EPA Regions in this same decision document, other Regions 

relied on prevailing wind patterns instead of the HYSPLIT model. This disparate 

treatment leads to an arbitrary decision for Wise County that would have been 

different had Wise County been in a Region that used the prevailing wind 

approach.

• Third, even applying the HYSPLIT model, EPA’s decision is arbitrary. The 

HYSPLIT model found only two days in four years of data when wind from Wise 

County entered the Dallas/Fort Worth (“DFW”) nonattainment area on high ozone 

days. On one of those days, the wind originated in a portion of the DFW 

nonattainment area and briefly looped through Wise County and re-entered the 

DFW nonattainment area. Thus, there is no rational and objective basis—even 

based on EPA’s faulty modeling—to support the Wise County determination. 

Correlating those two days to the 83 NAAQS exceedance days that EPA modeled 

further demonstrates that Wise County does not contribute to nonattainment. 

Every one of the days that EPA modeled is represented by a line on the following 

chart from EPA, with the two days where modeling suggests that wind may have 

blown from Wise County represented in red. The remaining spaghetti bowl of 

blue lines are all of the days when the modeling concluded that wind did not blow 

from Wise County. Given the wind pattern in the area that is demonstrated by the 

HYSPLIT modeling, it was arbitrary and capricious to conclude that Wise County 

is contributing to nonattainment in an area where the wind from Wise County 

almost never blows.
4

• Finally, since the comment period on the Rule closed, TCEQ has determined that 

it needs to correct an important emission factor underpinning the emissions 

inventory that EPA relied upon for Wise County, the factor for emissions of 

volatile organic compounds (“VOCs”) from condensate storage tanks at oil and 

gas operations. The pending correction is likely to result in a significantly lower 

estimate of emissions from Wise County, further undermining the basis for listing 

Wise County as being in nonattainment. Devon urges EPA at this time to 

reconsider and stay the determination, which would allow not only for the 

promise of unbiased decision making, but the opportunity to consider fully and 

fairly this corrected data before finalizing such a critical decision.

We respectfully do not make this request for reconsideration lightly, but urge the Agency 

to reconsider and stay its decision as to Wise County for the reasons articulated below, and 

because of the significant adverse impact the decision will have in the area in the interim. 

Headquartered in Oklahoma City, Devon is a leading independent oil and gas exploration and

production company, and the largest producer in the Barnett Shale area. Many of Devon’s 

production and midstream assets are located in Wise County, including gathering, transmission 

and a gas processing plant with a current capacity of 650 million cubic feet of natural gas per 

day, currently undergoing an expansion to 790 million cubic feet per day. Devon’s operations are 

focused onshore in the United States and Canada. While we fully share and support the EPA’s 

effort toward improved environmental quality in nonattainment areas, EPA’s decision to include 

Wise County in the DFW nonattainment area is not justified and unfortunately will lead only to 

severe economic harms with minimal environmental benefits. 

Devon estimates that the incorporation of Wise County into the DFW nonattainment area 

would impose significant compliance costs. Based on existing nonattainment rules for the DFW 

region, Devon’s capital cost of compliance in the first year of a nonattainment regulatory 

program is estimated to be $18MM. These costs are from engine modifications, additional 

control equipment and increased rental cost for leased compression to limit emissions from 

Devon’s compression fleet to 0.5 g NOx/hp-hr.

This nonattainment designation also puts Devon’s exploration and production (E&P) 

business at significant risk in future years. Since there are few ozone precursor source types in 

Wise County, it is reasonable to expect that E&P minor source facilities would be included in an 

emission offset program in the event that Reasonable Further Progress toward ozone attainment 

cannot be demonstrated (as was the case in this region in 2011). A limited supply of offsets is 

available to support oil and gas development in Wise County because of the multiple state and 

federal air quality regulations that are already in effect. To date, Devon has identified 

approximately 1000 future drilling sites in Wise County. For every well that wouldn’t be drilled 

because of offset limitations, lost net revenue is estimated to be approximately $17.2 million for 

each well not drilled. If Devon, for example, did not drill 25% of the remaining Wise County 

wells, the resultant decrease in revenue is estimated to be $4.3 billion. In addition, for each well 

not drilled in Wise County, an additional $2.95MM that Devon typically spends for outside 

services and supplies in Wise County would be lost.

This nonattainment designation is also likely to harm development of Barnett Shale, 

which currently provides an important source of natural gas to fuel industry and create jobs. 
5

Through Devon’s pioneering effort, the Barnett Shale has emerged as the largest natural gas field 

in Texas. The north Texas play has potential to remain one of the country’s most vital energy 

resources for many years to come. However, this potential is threatened by the designation of 

Wise County as being in nonattainment. 

President Obama has recognized that natural gas fosters a multitude of benefits and 

should play an increasingly important part of our energy future, stating in an Executive Order 

that:

[Natural gas] production creates jobs and provides economic benefits to 

the entire domestic production supply chain, as well as to chemical and 

other manufacturers, who benefit from lower feedstock and energy costs. 

By helping to power our transportation system, greater use of natural gas 

can also reduce our dependence on oil. And with appropriate safeguards, 

natural gas can provide a cleaner source of energy than other fossil fuels.1

In addition, EPA has already signaled the importance natural gas is likely to play in the future of 

energy production in the United States through its proposed New Source Performance Standards 

for greenhouse gas emissions from electric generating units, which if promulgated would compel 

the use of natural gas at most if not all new facilities. See Standards of Performance for 

Greenhouse Gas Emissions for New Stationary Sources: Electric Utility Generating Units, 

Docket ID No. EPA –HQ–OAR–2011–0660; FRL–9654–7, 77 Fed. Reg. 22,392 (Apr. 13, 

2012). EPA should not take unwarranted actions that threaten development of this important 

resource. 

The unnecessary impacts on jobs and the local and regional economies come at a time 

when the nation is working hard toward economic recovery and the promotion of gas as a critical 

and environmentally favorable alternative to coal. Unfortunately, EPA’s decision regarding 

Wise County is likely to have a long lasting adverse impact given that when a county is 

identified as nonattainment, it has the potential to remain that way until the air quality of the 

entire nonattainment area returns to attainment, even if attainment is achieved earlier in that 

county. The growth in the DFW area may make achieving attainment for the entire area difficult 

and could even result in increasingly stringent emission control requirements for the area, further 

impeding economic activity. Here, there is no rational reason to impose such burdens on Wise 

County.

For all of these reasons, Devon urges EPA to reconsider the Rule and stay the 

effectiveness of the Rule as to Wise County pending reconsideration. 

 1 Executive Order, Supporting Safe and Responsible Development of Unconventional Domestic Natural Gas 

Resources (Apr. 13, 2012).
6

I.

Section 307(d)(7)(B) of the Act provides for EPA’s reconsideration of a Clean Air Act 

(“CAA”) rule upon objection by a petitioner. See 42 U.S.C. § 7607(d)(7)(B). EPA must grant 

reconsideration when the petitioner: 

Standards for reconsideration and stay

[C]an demonstrate to the Administrator that it was impracticable to 

raise [an] objection [during the period for public comment] or if 

the grounds for such objection arose after the period for public 

comment ... and if such objection is of central relevance to the 

outcome of the rule.

Id. In such a situation, reconsideration is mandatory, as the CAA commands that EPA “shall

convene a proceeding for reconsideration of the rule and provide the same procedural rights as 

would have been afforded had the information been available at the time the rule was proposed.” 

Id. (emphasis added). Further, EPA is authorized to stay the effectiveness of rules promulgated 

under the CAA. See id. In addition, general principles of administrative law permit an interested 

party to apply to EPA for relief from a rule at any time for any relevant reason.

This Petition satisfies the standard for reconsideration for several reasons. First, as 

described below, the full scope of Dr. Armendariz’s views and predisposition against oil and gas 

development—views which he clearly indicated he adopted into his official capacity as the chief 

federal environmental regulatory official for the EPA region that includes Texas—were not made 

public during the comment period; news reports detailing certain comments of relevance to this 

decision emerged in the week before Administrator Jackson signed the final Rule. 

In addition, EPA included new—and flawed—modeling work as part of its final technical 

support document that was not made available during the comment period and that became the 

basis for critical conclusions on which EPA relied in supporting the nonattainment determination 

of Wise County. As part of that modeling, EPA—for the first time in the final Rule—also 

published and relied on a novel standard for what the Agency apparently considers 

“contribution” to ambient air quality for Wise County only.2

Finally, there is a new recognition by TCEQ that a crucial emission factor upon which 

EPA relied in the Wise County determination needs to be corrected, and the likely outcome of 

 That standard was not identified in 

the proposed rule and thus was not a possible topic for comment, nor does it appear to have been 

applied in any other EPA region. Commenters such as Devon thus could not have commented 

on this standard. In fact, by the standards applied in other EPA regions, Wise County would not 

have been listed in nonattainment. Thus, it was inappropriate and arbitrary for EPA in the final 

Rule to apply a disparate standard in Region 6 which purported to capture Wise County where 

other regions would not, and Devon was entitled to the opportunity to comment on such 

disparate treatment. Because the methodology EPA utilized in the final Rule was not a logical 

outgrowth of the proposal, and for the reasons stated below, EPA must grant reconsideration.

 2 See EPA, Dallas-Fort Worth, Texas Final Area Designations for the 2008 Ozone National Ambient Air Quality 

Standards at 17-20 (“Final DFW TSD”) (modeling to determine “the number of days an impact was over 1% (0.75 

ppb) on a modeled exceedance of the 75 ppb standard and also model exceedances greater than 70 ppb”).
7

that correction will be a significant reduction in estimated Wise County VOC emissions. Based 

on the Final DFW TSD, it is clear that EPA placed significant weight on the total estimated 

amount of VOC emissions in Wise County associated with Barnett Shale oil and gas production 

in making the nonattainment determination. Had the total estimated amount more accurately 

reflected actual VOC emissions from such operations, EPA may have concluded differently. This 

issue could not have been developed further during the comment period because TCEQ had not 

yet commenced working on a revised VOC emissions factor. Reconsideration is therefore 

necessary and an accompanying stay is warranted until TCEQ can complete and submit the 

revised VOC emissions factor, and EPA can consider it. See 42 U.S.C. § 7607(d)(7)(B). 

In addition to the fundamental logical outgrowth flaws, EPA did not adequately justify or 

explain why it promulgated the specific regulations that it included in the final Rules, as it is 

required to do. See CAA § 307(d)(6)(A) (“The promulgated rule shall be accompanied by . . . 

(ii) an explanation of the reasons for any major changes in the promulgated rule from the 

proposed rule.”); see also Motor Vehicle Mfrs. Ass’n v. State Farm Mut. Auto. Ins. Co., 463 U.S. 

29, 43 (1983) (an agency must “articulate a satisfactory explanation for its action including a 

rational connection between the facts found and the choice made.” (internal quotation omitted)). 

Further, the CAA requires EPA to provide “a response to each of the significant comments, 

criticisms, and new data submitted in written or oral presentations during the comment period.”

See CAA § 307(d)(6)(B). EPA’s failures to provide adequate justification and explanations 

further justify reconsideration. 

Pending reconsideration, the Administrator should stay the application of the Rule. 

Under the APA, “[w]hen an agency finds that justice so requires, it may postpone the effective 

date of action taken by it, pending judicial review.” 5 U.S.C. § 705. EPA has applied this 

standard to Clean Air Act cases.3

When an agency finds that justice so requires, it may postpone the 

effective date of action taken by it, pending judicial review. On 

such conditions as may be required and to the extent necessary to 

prevent irreparable injury, the reviewing court . . . may issue all 

necessary and appropriate process to postpone the effective date of 

an agency action or to preserve status or rights pending conclusion 

of the review proceedings.

 The standard for such an administrative stay is significantly 

different from the standard for a stay used by the courts because it does not require a 

demonstration of irreparable harm. This is clear from the text of the APA:

Thus, the APA deliberately contrasts what is required for an administrative stay—“justice so 

requires”—and a judicial stay—“conditions as may be required” and “irreparable harm.” 

Similarly, CAA Section 307(d)(7)(B) authorizes an administrative stay, but does not premise that 

stay on a finding of irreparable injury. Such differences must be given effect,4

 3 See, e.g., Ohio: Approval and Promulgation of Implementation Plans, 46 Fed. Reg. 8,581, 8,582 n.1 (Jan. 27, 

1981).

so there is no 

4 “[W]here Congress includes particular language in one section of a statute but omits it in another section of the 

same Act, it is generally presumed that Congress acts intentionally and purposely in the disparate inclusion or 
8

irreparable harm requirement for an administrative stay. Given the potential impact of these 

regulations on Devon and the surrounding economy that depends on the development of the 

Barnett Shale, “justice so requires” that EPA stay the Rules and take other necessary and 

appropriate steps to defer the compliance deadlines and other provisions of the Rules until the 

outcome of the reconsideration process. Even were a petitioner required to meet the factors for a 

judicial stay, Devon would do so here. As discussed below in Section III, Devon will be 

irreparably harmed if the Rule goes into effect and those harms will spread to others in Wise 

County and Texas. By comparison, there will be essentially no environmental impact if EPA 

stays the Rule while it conducts reconsideration. 

II.

A.

Grounds for Reconsideration 

It is only with significant regret and reluctance that Devon is compelled to urge EPA to 

reconsider the Wise County designation to remove the shadow of bias and lack of objectivity 

currently cast on the Agency’s final decision. After the close of the comment period for EPA’s 

re-designation of Wise County, Texas, and just days before Administrator Jackson signed the 

Rule, the public learned for the first time that then EPA Region 6 Administrator Armendariz, 

who had leadership and delegated responsibility for the re-designation, had made incendiary 

statements demonstrating bias in his regulatory approach against the Texas oil and gas industry. 

In particular, the media widely reported a video of Dr. Armendariz from 2010, in which he 

indicated his view that EPA should “crucify” oil and gas companies. Speaking to a group in 

Dish, Texas, Dr. Armendariz indicated that he would enforce the Clean Air Act against oil and 

gas companies “like how the Romans used to conquer little villages in the Mediterranean.” Mike 

Sorahan, Inhofe to Investigate EPA’s Handling of Drilling Complaints, Greenwire (Apr. 25, 

2012).

EPA Should Decide the Attainment Status of Wise County Free from Any 

Shadow of Bias

5

These comments were made prior to his determination to change the attainment status of 

regarding Wise County, but were not disclosed to the public until after the comment period 

closed. Indeed, approximately a year after these inflammatory comments, but well before they 

became public, Dr. Armendariz personally notified the Governor of Texas that EPA would be 

taking the rare and extraordinary step of overruling the Governor’s recommendations on air 

quality designations for ozone. In particular, Dr. Armendariz indicated that EPA intended to 

designate Wise County as nonattainment. See Letter from Al Armendariz to Governor Rick 

Perry (Dec. 9, 2011). Wise County has a relatively small population compared to most counties 

within the DFW nonattainment area, but it does have substantial oil and gas production as part of 

the development of the Barnett Shale, and this oil and gas production has increased in recent 

 He explained that the Romans would “go into a little Turkish town somewhere, they’d 

find the first five guys they saw and they would crucify them. And then you know that town was 

really easy to manage for the next few years.” Id. Dr. Armendariz noted that EPA would “hit” 

oil and gas companies “as hard you can and you make examples out of them.” Id. 

 exclusion.” Russello v. United States, 464 U.S. 16, 23 (1983) (quotation marks and citation omitted; alteration in 

original).

5 Available at www.eenews.net/eenewspm/print/2012/04/25/2.
9

years. The presence of this oil and gas production appears to be a significant factor in EPA’s 

decision to designate Wise County in nonattainment, as EPA emphasized the emissions from oil 

and gas production in Wise County in its Final DFW TSD supporting the designation of Wise 

County as nonattainment. See id. at 23.6

Furthermore, Dr. Armendariz has an extensive history of focus on and views related to 

the development of oil and gas production in the Barnett Shale. Indeed, Dr. Armendariz 

addressed these issues in a controversial report he authored in 2009 before joining EPA, which 

focused specifically on the emissions from oil and gas production in the Barnett Shale Area. See 

Al Armendariz, Emissions from Natural Gas Production in the Barnett Shale Area and 

Opportunities for Cost-Effective Improvements 3-4 (Jan. 26, 2009) (“Armendariz Report”) 

(addressing the emissions from oil and gas production in Wise County, among others). TCEQ 

and others have criticized the report as being based on non-comparable data and exaggerating the 

relative significance of the emissions from the Barnett Shale with regard to ozone formation in 

the Dallas-Fort Worth area.

 

7

During the comment period on EPA’s re-designation, no interested party had a basis to 

appreciate the hostility toward the oil and gas industry that Dr. Armendariz’s 2010 comments 

demonstrated and which he brought to his role as the chief federal environmental regulator in 

Texas. Only in April 2012 did interested parties learn of these views through media reports. As 

reported by the media, this newly discovered and extreme hostility toward oil and gas companies 

spurred Congress to investigate the handling of the oil and gas industry by Dr. Armendariz and 

EPA. See Sorahan, infra. 

In the end, amid these strong allegations of bias in conducting his official duties, Dr. 

Armendariz resigned on April 29, 2012. See Mike Soraghan, Embattled appointee resigns over 

‘crucify’ comment, Greenwire (Apr. 30, 2012).8

 Only one day after Dr. Armendariz’s 

resignation, Administrator Jackson signed the Final Rule. 77 Fed. Reg. at 30,095 (noting 

Administrator Jackson’s April 30, 2012 signature). Dr. Armendariz recently joined the Sierra 

Club in June in the midst of a continuing investigation by Congress. See Emily Foxhall, Former 

EPA Official Al Armendariz Joining Sierra Club, The Texas Tribune (June 29, 2012)9

; see also

Jeremy P. Jacobs, Hill GOP pounces on report that Armendariz visited Sierra Club, Greenwire 

(June 8, 2012).10

 6 The final rule promulgated by EPA does not contain any detailed discussion of the basis for its designation of Wise 

County, Texas, as being in nonattainment with the 2008 8-hour ozone NAAQS. Instead, the technical support 

documents for each area appears to serve as the decision document for that area, combined with further explanations 

in EPA’s Response to Significant Comments, Docket No. EPA-HQ-OAR-2008-0476 (Apr. 2012) (“RTC”).

 

7 See TCEQ, Analysis of Emissions from Natural Gas Production in the Barnett Shale (2009), available at 

http://www.bseec.org/sites/all/pdf/airquality/17.pdf. 

8 Available at www.eenews.net/Greenwire/print/2012/04/30/1.

9 Available at http://www.texastribune.org/texas-environmental-news/environmental-problems-andpolicies/armendariz-joins-sierra-club/.

10 Available at http://www.eenews.net/EEDaily/2012/06/08/archive/6?terms=armendariz.
10

To be clear, Devon does not raise these points to further a political debate or extend an 

ongoing controversy for the Agency. At the same time, there can be no doubt that Dr. 

Armendariz’s comments and actions, which were not apparent at the time of the comment 

period, raise fundamental issues regarding the objectivity of his recommendation on the 

nonattainment determination that must be fully considered by the Agency. Reconsideration of 

EPA’s re-designation of Wise County as nonattainment is warranted because Dr. Armendariz’s 

acknowledged bias against the oil and gas industry—which led to his resignation just days before 

the Administrator adopted his recommendation—has tainted this determination for the entire 

Agency. “Decisionmakers violate the Due Process Clause and must be disqualified when they 

act with an ‘unalterably closed mind’ and are ‘unwilling or unable’ to rationally consider 

arguments.” Air Transp. Ass’n of Am. v. Nat’l Mediation Bd., 663 F.3d 476, 487 (D.C. Cir. 

2011). Dr. Armendariz’s extraordinary comments about his approach to regulating oil and gas 

companies go beyond just personal views, but reveal a fundamental view as a regulator that 

indicates a closed mind and an inability to rationally consider the designation of Wise County, 

which involves the two areas that Dr. Armendariz explicitly criticized: growth of the oil and gas 

industry and the Barnett Shale. Indeed, the Final DFW TSD supporting EPA’s Rule specifically 

notes the “high growth in [area] emissions is due in large part to growth in emissions from 

Barnett Shale gas production,” id. at 23, and Dr. Armendariz in 2009 had already concluded that 

Wise County was one of the largest oil and gas producing county in the Barnett Shale area. 

Armendariz Report at 3. Dr. Armendariz’s open hostility toward the oil and gas industry shows 

that he was “incapable of giving fair consideration to the” proper designation of Wise County. 

Lead Indus. Ass’n v. EPA, 647 F.2d 1130, 1179 (D.C. Cir. 1980). His prior views on oil and gas 

production in the Barnett Shale in combination with his hostility toward oil and gas companies 

appears to have infected his views on whether to designate Wise County as nonattainment. 

This hostility toward oil and gas development in the Barnett Shale, and in Wise County in 

particular, is only affirmed by the puzzling lack of sound basis for listing Wise County in 

nonattainment and the disparate treatment by Region 6 compared to other regions. As 

demonstrated by comments and as discussed below, there was no rational basis for listing Wise 

County in nonattainment. The wind direction, the air modeling and the rest of the record all 

point to the conclusion that Wise County should not be listed in nonattainment. 11

Dr. Armendariz’s open and notorious hostility to the oil and gas industry cannot be 

dismissed as a mere discussion of policy, see Ass’n of Nat’l Advertisers, Inc. v. FTC, 627 F.2d 

 Yet, under Dr. 

Armendariz’s leadership, Region 6 led EPA to decide to list Wise County in nonattainment. The 

only demonstrable factors that distinguish Wise County from other similarly situated areas that 

were not designated as nonattainment are the oil and gas development in the county and Dr. 

Armendariz’s longstanding concerns regarding such industry which predated his EPA tenure and 

explicitly continued into this particular rulemaking.

 11 Importantly, the very same flaws that plagued Dr. Armendariz’s Report plague his recommendation to designate 

Wise County as nonattaintment—namely, they both rely on erroneous conclusions about the direction the wind

blows and the possible impact of this area on smog in the Dallas-Fort Worth area. See Methodology of Barnett 

Shale Emissions Study Raises Concerns: Unrelated Data, Improper Assumptions Dramatically Overstate Findings. 

Contrary to the findings of the report and Rule, the wind from Wise County blows away from the DFW area almost 

all of the time. This further raises a shadow of bias that brought Dr. Armendariz’s personal views into the official 

decision making process here.
11

1151, 1171 (D.C. Cir. 1979), nor can it be considered advocacy on an open legal question, 

Gersman v. Grp. Health Ass’n, 931 F.2d 1565 (D.C. Cir. 1991). Rather, it regrettably reveals a 

deep-seated animosity and a “single-minded commitment” toward disparate treatment of a 

particular industry that is prominent in Wise County. Lead Indus., 647 F.2d at 1179. Now that 

EPA has taken action to replace Dr. Armendariz, we urge the Agency to take similar necessary 

action regarding a decision that is clearly cast in doubt as a result of his key involvement and the 

apparent injection of his personal bias into the official recommendation and decision. EPA 

should reconsider and stay the determination, and should it proceed through a further notice and 

comment process, Devon commits to assist the Agency in participating and providing 

information to make a decision that upholds the Agency’s principles of “scientific integrity, rule 

of law and transparency,” as described by Administrator Jackson on her first day leading the 

Agency.12 As President Obama’s January 2011 executive order makes clear, our regulations 

“must be based on the best available science,” not personal bias, and “must take into account 

benefits and costs, both quantitative and qualitative.”13

B.

 

In designating Wise County to be in nonattainment, EPA relies upon section 107(d) of 

the Clean Air Act, pursuant to which EPA says it “must designate an area ‘nonattainment’ if it is 

violating the 2008 ozone NAAQS or if it is contributing to a violation of the 2008 ozone 

NAAQS in a nearby area.” Final DFW TSD at 1. Since Wise County does not contain any 

ozone monitoring sites, it necessarily is not violating the 2008 ozone NAAQS and would 

otherwise be “attainment/unclassifiable.” Thus, EPA was required to demonstrate that emissions 

from Wise County contributed to a violation of the 2008 ozone NAAQS in a nearby area in order 

to include it within the DFW ozone nonattainment area (“NAA”). 

EPA Justified the Final Designation of Wise County as in Nonattainment 

Based on New, Flawed, and Inadequate Modeling

In the Final DFW TSD, EPA presents technical arguments using a five factor analysis 

and concludes that Wise County should be included in the DFW ozone NAA. However, EPA 

utterly fails to demonstrate that Wise County is violating or contributing to a violation of the 

2008 ozone NAAQS in the DFW NAA. 

EPA used two approaches in an attempt to link emissions from Wise County to a 

violation of the 2008 ozone NAAQS in a nearby area: (1) ozone source apportionment modeling 

performed by TCEQ where EPA analyzed the ozone contribution of Wise County emissions to 

daily maximum 8-hour ozone concentrations at monitoring sites on high ozone days; and (2) 

HYSPLIT back trajectories to the locations of monitoring sites on days that exceed the 2008 

ozone NAAQS during 2006-2010.14

 12 Administrator Lisa P. Jackson, Opening Memo to EPA Employees (Jan. 23, 2009), available at 

 Neither model demonstrates that Wise County is 

http://blog.epa.gov/administrator/2009/01/26/opening-memo-to-epa-employees/. 

13 Executive Order, Improving Regulation and Regulatory Review (Regulatory Review Order) (Jan 18, 2011), 

available at http://www.whitehouse.gov/the-press-office/2011/01/18/improving-regulation-and-regulatory-reviewexecutive-order. 

14 EPA focused on the Wise County contributions to ozone concentrations at three monitoring sites, the Keller 

(“KELC”) and Eagle Mountain Lake (“EMTL”) monitors in Tarrant County and a monitor in Parker County. The 

2008-2010 8-hour ozone Design Values at KELC and EMTL were 0.086 and 0.085 ppm, respectively, so they 
12

contributing to a violation of the 2008 ozone NAAQS such that the county should be listed as 

being in nonattainment. 

1. EPA’s newly released, and flawed, analysis of TCEQ’s ozone source 

apportionment modeling does not demonstrate that Wise County is 

contributing to violations of the 2008 ozone NAAQS

In order to support its conclusion that Wise County should be listed as being in 

nonattainment, EPA for the first time in the final Rule deconstructed and reanalyzed source 

apportionment modeling provided to EPA by TCEQ. See Final DFW TSD at 15-20. TCEQ 

submitted the ozone source apportionment modeling and indicated that its modeling 

demonstrated that Wise County should not be listed in nonattainment. However, EPA in the 

final Rule relied heavily on its own re-analysis of TCEQ’s modeling in order to reach its decision 

to list Wise County in nonattainment. In its “Conclusion” section of the Final DFW TSD, EPA 

added a conclusion to the Wise County discussion that is based completely on this analysis. Id. 

at 23 (“Source apportionment modeling for a portion of an ozone season indicates that emissions 

from Wise County can contribute to observed violations in the DFW nonattainment area.”). 

EPA’s analysis is both faulty and not a logical outgrowth of the proposal, requiring that the 

public have an opportunity to comment on such analysis prior to EPA’s incorporation of such 

analysis into a final Rule.

As background, the following is a brief summary of EPA’s analysis:

• EPA analyzed TCEQ’s ozone source apportionment modeling that used the 

CAMx model and its Anthropogenic Precursor Culpability Assessment (“APCA”) 

ozone source apportionment tool to estimate the ozone contributions due to Wise 

County at ozone monitoring sites on days the modeled concentrations exceeded 

the ozone NAAQS (ozone > 75 ppb). 

• EPA also looked at the CAMx/APCA contributions of emissions from Wise 

County emissions when ozone was greater than 70 ppb, based on EPA’s concern 

that the model under predicts the observed maximum ozone concentrations. 

• In addition to looking at Wise County’s maximum and average contribution on 

high ozone days, EPA also determined the number of days the Wise County 

ozone contributions exceeded 1 percent of the NAAQS (0.75 ppb). 

• EPA found 6 monitor-days when CAMx/APCA Wise County ozone source 

apportionment exceeded the 0.75 ppb threshold during modeled exceedance 

conditions with no one monitor having more than one day. 

 violated the 8-hour ozone NAAQS. However, the 2008-2010 8-hour ozone Design Value for the Parker County 

monitor was 0.075 ppm, which is within the 8-hour ozone NAAQS. Thus, as EPA recognized, Wise County’s 

contribution to ozone at the Parker County monitoring site is unimportant in this exercise since it is not violating the 

March 2008 ozone NAAQS.
13

There are several fundamental flaws and legal deficiencies with EPA’s approach in the 

final Rule, as discussed below. 

a. Because commenters did not have an opportunity to review 

and critique this flawed analysis, which EPA relied upon for its 

conclusion, EPA should grant reconsideration 

As a fundamental matter, EPA’s new analysis of TCEQ’s modeling was not made 

available for comment. It was only made available as part of the Final DFW TSD. It was 

therefore impracticable for Devon to raise objections to the modeling work and the standard for 

“contribution” during the public comment period. Given the significant problems with EPA’s 

analysis highlighted below, and the potential that further errors will be discovered as the work is 

examined, reconsideration is absolutely necessary. See 42 U.S.C. § 7607(d)(7)(B). 

EPA’s inclusion of significant new issues in support of the final Rule is arbitrary and 

capricious because the new analysis is not a “logical outgrowth” of the Agency’s proposed rule. 

Envtl. Integrity Project v. EPA, 425 F.3d 992, 996 (D.C. Cir. 2005) (stating that “[t]he test is 

whether a new round of notice and comment would provide the first opportunity for interested 

parties to offer comments that could persuade the agency to modify its rule”). A “final rule is a 

‘logical outgrowth’ of a proposed rule only if interested parties should have anticipated that the 

change was possible, and thus reasonably should have filed their comments on the subject during 

the notice-and-comment period.” Id. (citations omitted). This rule exists because the public 

“must be able to trust an agency’s representations about which particular aspects of its proposal 

are up for consideration.” Id. at 998. Because EPA relied on an entirely new—and flawed—

basis for listing Wise County in nonattainment, which commenters were not able to review or 

critique, EPA must grant reconsideration and stay implementation of the Rule. As the following 

discussion demonstrates, there are important flaws in EPA’s new analysis and it does not follow 

the Agency’s past practice or guidance. 

a. The modeling assumed significantly higher emissions from 

Wise County than EPA has since recognized exist

EPA’s analysis of the TCEQ modeling failed to recognize an important limitation of the 

original TCEQ work. As TCEQ highlighted when describing its modeling, “TCEQ did not use 

the updated oil and gas sector pneumatic emissions submitted October 2011 to the EPA for the 

Periodic Emissions Inventory in this modeling and source apportionment analysis, therefore, the 

VOC emissions from this source category are likely overestimated in the modeling.”15

As EPA recognized, the updated oil and gas sector pneumatic emissions reflect better 

data than what EPA had used to support the proposal. RTC at 55-56. Further that data reflects 

significantly reduced emissions from Wise County. The revised emission inventory for Wise 

County is 25% lower—reducing the VOC emissions in Wise County by 6,048 tpy, from 23,657 

tpy to 17,609 tpy. 

 

 15 Comments submitted by Mark Vickery, Executive Director, TCEQ at 10 (EPA–OAR–HQ–2008–0476-0296).
14

Despite the fact that EPA accepted the fact that VOC emissions from Wise County are 

likely at least 25% lower than those used in the TCEQ modeling, the Agency failed to use that 

information. Given that EPA obtained the modeling files from TCEQ and redid some of the 

analysis for its own purposes (Final DFW TSD at 15-20), it clearly had the capability to utilize 

the newer VOC data. It’s failure to do so was arbitrary and capricious. Thus, the Agency should 

reconsider its reliance on modeling results that likely overstate the impact of Wise County. 

b. EPA’s analysis establishes a new, and heretofore undisclosed, 

1% standard for what the Region considers to be contribution 

In reanalyzing the TCEQ modeling, EPA in the final Rule for the first time established a 

threshold for what the Region considered significant enough to warrant concluding that a county 

is contributing to a violation. Specifically, EPA “used a 1% of the standard cut point for days 

where [the Agency] would consider ... Wise County’s impact to be significant.” Final DFW 

TSD at 17. Thus, EPA looked for the “number of days an impact was over 1% (0.75 ppb) on a 

modeled exceedance.” Id.

EPA had not proposed or used this 1% standard before for the DFW nonattainment area. 

EPA in the final Rule simply selected that standard from out of thin air and did not offer a 

rational basis for its use. Such an unjustified selection is arbitrary and capricious and warrants 

reconsideration. Further, other EPA regions have not applied such a 1% standard. As the D.C. 

Circuit has held, EPA cannot adopt arbitrary approaches across its regions, but must apply 

consistent standards across the Agency. “[The] County’s nonattainment designation is troubling 

because of the apparent inconsistency in EPA‘s approach to designations in different EPA 

regions.” Catawba County v. EPA, 571 F.3d 20, 51-52 (D.C. Cir. 2009). 

c. EPA’s reliance on the 1% standard is inconsistent with its 

conclusions for the Chicago area

Even more troubling than the fact that EPA did not disclose or use the 1% standard 

elsewhere, is the fact that the 1% standard (0.75 ppb) is much lower than the levels that EPA 

applied to other counties. EPA said it considers 2-4 ppb ozone contributions to be levels 

warranting designation as nonattainment for two counties that EPA concluded were contributing 

to nonattainment in the Chicago area (Lake and Porter counties).16

In fact, it appears that if Wise County were in the Chicago area, for example, it would not 

have been listed as being in nonattainment. EPA concluded that Jasper County, which EPA 

determined to be contributing 0.5 ppb should not be considered to be contributing to 

nonattainment. The primary driver for the decision not to list Jasper County is that EPA did not 

 Those levels are 267% to 

533% higher than the 0.75 ppb level that EPA points to for the DFW area. 

 16 EPA, Chicago-Naperville, Illinois-Indiana-Wisconsin Area Designation for the 2008 Ozone National Ambient Air 

Quality Standards at 18 (“In keeping with EPA’s ozone contribution levels used to select states that should be 

covered in regional emission control programs, 2 ppb to 4 ppb ozone concentration contributions are considered to 

be significant ozone contributions.”).
15

consider a 0.5 ppb contribution significant enough to warrant listing.17 At that level, EPA 

“concluded that emissions from Jasper County do not meaningfully contribute to the high ozone 

concentrations at the Zion monitor.”18

d. EPA’s calculations for the 1% standard are flawed and do not 

represent contributions to NAAQS violations

By comparison, EPA calculated a maximum Wise County 

contribution of 0.86 ppb to the Eagle Mountain Monitor. That contribution is far more consistent 

with the 0.5 ppb contribution from Jasper County (not listed in nonattainment) than it is for the 

2-4 ppb contributions from Lake and Porter counties (listed as in nonattainment). As the D.C. 

Circuit has made clear, “[s]uch inconsistent treatment is the hallmark of arbitrary agency action.” 

Catawba County, 571 F.3d at 51-52. Regardless of whether EPA set a benchmark at 0.5 ppb, 

0.75 ppb, or 2-4 ppb, EPA was obligated to make this information available for notice and 

comment. EPA has not done so. Every one of those potential standards was first raised in 

EPA’s final technical support documents. Given the centrality of the issue—and the fact that 

EPA did not take this approach in any other region—reconsideration is warranted. See 42 U.S.C. 

§ 7607(d)(7)(B). 

A central flaw in EPA’s analysis is that it confuses exceedances of the NAAQS with 

violations of the NAAQS. An exceedance of the 2008 ozone NAAQS is when ozone exceeds 

the 75 ppb standard. A violation of the 2008 ozone NAAQS occurs when an observed 8-hour 

ozone Design Value is above 0.075 ppm (i.e., 76 ppb or higher). The 8-hour ozone Design 

Value is defined as the three-year average of the fourth highest daily maximum 8-hour ozone 

concentration at a monitor.19

Rather than focusing on determining whether Wise County is contributing to violations of 

the NAAQS, EPA’s analysis of TCEQ’s modeling focused on daily contributions to ozone 

exceedances. As EPA explained, it “determined the number of days an impact was over 1% 

(0.75 ppb) on a modeled exceedance of the 75 ppb standard and also model exceedances greater 

 The determination of nonattainment areas for the 2008 ozone 

NAAQS was based on ozone Design Values using measured air quality from the 2008-2010 

three year period. Thus, to show Wise County contributes to a violation of the 2008 ozone 

NAAQS then its contributions to 8-hour ozone Design Values needs to be evaluated at monitors 

where the 8-hour ozone Design Values are above the ozone NAAQS, which was not done in 

EPA’s DFW ozone NAA determination.

 17 EPA, Chicago-Naperville, Illinois-Indiana-Wisconsin Area Designation for the 2008 Ozone National Ambient Air 

Quality Standards at 21 (“Jasper County contributes 0.5 ppb to the Zion monitor. .... It is concluded that emissions 

from Jasper County do not meaningfully contribute to the high ozone concentrations at the Zion monitor.”). See also

EPA, Addendum to Responses to Significant Comments on the State and Tribal Designation Recommendations for 

the 2008 Ozone National Ambient Air Quality Standards (NAAQS) for Section 3.2.5.1. Chicago-Naperville, IL-INWI area at 10-11 (“[T]he ozone contribution potential of Jasper County, Indiana is relatively small, on the order of 

0.0005 ppm (0.5 ppb) or less, supporting the exclusion of Jasper County from the Chicago-Naperville, IL-IN-WI 

ozone nonattainment area for the 2008 ozone NAAQS.”)

18 EPA, Chicago-Naperville, Illinois-Indiana-Wisconsin Area Designation for the 2008 Ozone National Ambient Air 

Quality Standards at 21 (“Jasper County contributes 0.5 ppb to the Zion monitor. .... It is concluded that emissions 

from Jasper County do not meaningfully contribute to the high ozone concentrations at the Zion monitor.”).

19 http://www.epa.gov/air/criteria.html. 
16

than 70 ppb.” Final DFW TSD at 17. EPA then looked at how many times Wise County had an 

impact of more than 0.75 ppb on DFW. Id. at 18. This analysis does not provide an answer to 

EPA’s question of whether Wise County “is contributing to a violation of the 2008 ozone 

NAAQS in a nearby area.” Id. at 1. In fact, as discussed Section II.B.2, the exceedance days that 

EPA identified where wind from Wise County may have reached the Eagle Mountain monitor 

are ones where the exceedance was modest. They are not the days that were used to determine 

whether there was a violation. 

e. EPA’s approach of focusing on exceedances rather than 

violations is inconsistent with past Agency practice. 

For the Cross State Air Pollution Rule (CSAPR20

Unlike for CSAPR, which examined impacts on the 8-hour ozone Design Values that 

define whether an area is violating the ozone NAAQS, for the DFW nonattainment area 

determination, EPA looked at modeled exceedance days. This distinction matters because of the 

form of the ozone NAAQS—in which a monitoring site is allowed to have exceedances of the 

NAAQS without causing a violation—and the need for EPA to demonstrate that Wise County 

contributes to a violation of the ozone NAAQS in a nearby area. As discussed below, the 

distinction also matters in this case because the Wise County contribution to the 8-hour ozone 

Design Value is far lower than the Wise County’s contribution to a few individual exceedances. 

) EPA had a similar issue to address, 

which was how to determine when an upwind state has a significant contribution to downwind 

ozone nonattainment. For CSAPR, EPA calculated the contribution of a state’s anthropogenic 

emissions to 8-hour ozone Design Values using the same CAMx/APCA ozone source 

apportionment tool as used in the DFW nonattainment area determination. If a state’s 

contribution to a downwind state’s 8-hour ozone Design Value that violated the NAAQS 

exceeded 1 percent of the NAAQS (0.75 ppb), then the state was determined to have a significant 

contribution and was subject to the ozone seasonal NOx control requirements of CSAPR. 

EPA’s methodology is also inconsistent with past Agency practice because it is focused 

on absolute, rather than relative, results. The values that EPA reported in tables 13 and 14 of the 

Final DFW TSD are absolute results from the model and these are the results that EPA based its 

conclusions on. By comparison, when the TCEQ staff analyzed their CAMx/APCA source 

apportionment modeling results for Wise County, they used the model in a relative sense to scale 

the observed ozone Design Values. TCEQ calculated projected 2012 8-hour ozone Design 

Values with and without the CAMx/APCA contribution of emissions from Wise County at each 

monitoring site in the DFW area. 

TCEQ’s approach is the one recommended in EPA’s modeling guidance for how to 

project ozone Design Values (EPA, 200721

 20

). EPA modeling guidance recommends that the 

model be used in a relative, rather than absolute, sense (EPA, 2007, p. 18) to scale the observed 

ozone Design Values to obtain a projected ozone Design Value. EPA states that using the model 

in a relative sense is more reliable than using the absolute model results since it anchors the 

http://www.epa.gov/airtransport/. 

21 http://www.epa.gov/ttn/scram/guidance/guide/final-03-pm-rh-guidance.pdf. 
17

future ozone projections to the observations (reality) and reduces the uncertainty in the 

calculations. 

TCEQ’s approach is also consistent with the approach used by EPA for CSAPR. In 

CSAPR, EPA estimated projected 2012 ozone Design Values due to all sources and then with a 

state’s ozone contribution removed. The difference was the state’s ozone contributions to the 8-

hour ozone Design Value with the contribution determined to be significant if it was greater than 

or equal to 1 percent of the 1997 ozone NAAQS (0.85 ppb or higher). However, when tasked 

with a similar exercise for Wise County, EPA decided to not follow its own modeling guidance 

and previous procedures developed for CSAPR and they performed a completely different 

analysis that examines daily contributions to ozone exceedances, which does not show a 

contribution to a violation of the NAAQS. 

Given that EPA’s approach is inconsistent with its own guidance and past practice, 

whereas TCEQ’s approach is consistent with both, EPA should grant reconsideration and rely on 

TCEQ’s results.22 TCEQ originally reported its contributions to the 2012 future design value as 

percentages (TCEQ Comments, Table 3), showing that Wise County only contributed roughly 

half a percent (0.53%) to the Eagle Mountain Lake monitor (M. Vickery, 201223

TCEQ’s results, as reported in parts per billion, demonstrate that the county should not be 

listed in nonattainment. Using projected 2012 8-hour ozone Design Values of 78.06 and 76.05 

ppb from the DFW ozone SIP for the Eagle Mountain Lake (“EMTL”) and Keller (“KELC”) 

monitors, respectively, we find that Wise County contributes 0.41 and 0.008 ppb to the projected 

2012 8-hour ozone Design Values at the two monitoring sites. See Table 1 below.

). That result 

alone demonstrates that Wise County’s contribution is not sufficient to list the county in 

nonattainment, a conclusion which is reinforced when the contribution is estimated in parts per 

billion.

The 0.41 ppb contribution from Wise County is far below any threshold that EPA has 

previously used. It is well below the 0.75 ppb threshold referenced by EPA in the Final DFW 

TSD. It is similarly below the same 0.85 ppb threshold used in CSAPR. Further, it is well below 

the 2-4 ppb threshold that EPA used in the Chicago technical support document. Finally, it is 

even below the 0.5 ppb threshold for Jasper County that EPA, a level at which EPA determined 

emissions “do not meaningfully contribute to the high ozone concentrations at the [nearby] 

monitor.24

 22 Since EPA should have used the model in a relative, rather than an absolute, sense, EPA’s concern about TCEQ 

having used the average of the predicted ozone levels in the grid cells around the monitor, rather than the maximum, 

should make very little difference. The relative difference between the maximum levels should not be significantly 

different than the difference between the average levels. 

Thus, Wise County does not contribute significantly to a violation of the 2008 ozone 

NAAQS in a nearby area.

23 Technical Analysis Support Documentation by the Texas Commission on Environmental Quality (TCEQ) 

Regarding U.S. Environmental Protection Agency (EPA) Responses to State and tribal 2008 Ozone Designation 

Recommendations (with cover letter from Mark. Vickery, Executive Director, TCEQ, January 11, 2012).

24 EPA, Chicago-Naperville, Illinois-Indiana-Wisconsin Area Designation for the 2008 Ozone National Ambient Air 

Quality Standards at 21.
18

Table 1. Wise and Hood Counties contributions to projected 2012 8-hour ozone Design Values 

using TCEQ’s CAMx/APCA ozone source apportionment modeling results.

Source Region EMTL

DV Contribution

KELC

DV Contribution

 Hood County 0.08% 1 0.01%

 Wise County 0.53% 1 0.01%

 DFW+Other 76.52% 1 78.04%

 IC/BC 22.86% 1 21.93%

APCA DVF 100% 1 100%

DFW SIP 2012 DVF 78.06 ppb 2 76.45 ppb

 Hood County 0.06 ppb 0.008 ppb

 Wise County 0.41 ppb 0.008 ppb

 DFW+Other 59.73 ppb 45.66 ppb

 IC/BC 17.84 ppb 16.77 ppb

1. Technical Analysis Support Documentation by the Texas Commission on Environmental Quality (TCEQ) 

Regarding U.S. Environmental Protection Agency (EPA) Responses to State and tribal 2008 Ozone Designation 

Recommendations (M. Vickery, TCEQ, January 11, 2012).

2. DFW Ozone SIP Table 6-4 page C-126 

(http://www.tceq.texas.gov/assets/public/implementation/air/sip/dfw/ad_2011/AppC_CAMx_ado.pdf).

2. EPA’s HYSPLIT modeling supports the conclusion that Wise County 

is not contributing to a violation of the 2008 ozone NAAQS

EPA fundamentally erred in both applying the HYSPLIT model and relying on results 

which demonstrate the precise contrary of EPA’s conclusion: that Wise County is not

contributing to a violation of the 2008 ozone NAAQS. First, HYSPLIT modeling provides no 

information regarding the actual formation or transport of ozone, so it is a tool of limited, if any, 

usefulness for determining ozone contribution. Second, EPA’s HYSPLIT modeling results show 

that it is only in the rarest of instances that wind from Wise County actually reaches a monitor 

exceeding the NAAQS threshold. Thus, there was—and remains—no basis for EPA to conclude 

that Wise County is contributing to violations of the 2008 ozone NAAQS.

At the outset, HYSPLIT is fundamentally incapable of providing any kind of assessment 

of the ozone contribution due to emissions from Wise County. EPA used the HYSPLIT model 

to perform 24-hour back trajectory analysis from the locations of the KELC and EMTL 

monitoring sites on every observed ozone exceedance day (i.e., ozone ≥ 0.076 ppm) from the 

five year period of 2006-2010. As run by EPA, the HYSPLIT model follows the path of a 

particle or parcel of air starting above an ozone monitoring site backwards in time over 24-hours. 

The particle or parcel path does not account for dispersion or chemical transformation that is 

necessary to estimate ozone concentrations. It therefore cannot be used to determine causation, 

i.e., that any particular “particle” or “parcel” of ozone contributed to nonattainment in a 

downwind receptor. It just provides an ambiguous and uncertain indication of the general areas 

that were upwind of a monitoring site on days with ozone exceedances. Put differently, the 

HYSPLIT modeling just shows where the wind may be blowing from and provides no 

information regarding whether that wind is carrying ozone or any ozone precursors. 
19

EPA notes in the DFW ozone NAA determination that the ozone exceedance day 

HYSPLIT back trajectories indicate that air transported from Wise County reaches the area of 

the EMTL monitor. However, the actual data presented by EPA indicate otherwise. The figure 

below is based on Figure 5a from EPA’s DFW ozone NAA determination document. Figure 5a 

indicates ozone air parcels that arrived at the EMTL monitor during ozone exceedance 

conditions originated to the east to southeast of the EMTL monitor in the opposite direction of 

Wise County. Of the 83 back trajectories, only one appears to pass through Wise County. A 

second path blows from the area exceeding the NAAQS threshold, briefly passes over Wise 

County and then loops back and returns to the exceeding area. Rather than suggesting that Wise 

County contributes to violations of the 2008 8-hour ozone NAAQS at the EMTL monitoring, 

EPA’s Figure 5a indicates that the wind may have blown over Wise County once in five years 

when there was an exceedance, but all other exceedances occurred when winds were blowing in 

the opposite direction from Wise County. Given that, the best interpretation of EPA’s HYSPLIT 

modeling results is that Wise County is not contributing to a violation of the NAAQS. 

Finally, the two days in which the HYSPLIT modeling indicates that wind passing over 

Wise County may have reached the monitor are days with minimal exceedances of the standard, 

not days that are used to calculate the violations of the ozone NAAQS. Table 2 lists the 

observed daily maximum 8-hour ozone concentrations at the EMTL monitoring site for the 83 

days during 2006-2010 that exceeded the March 2008 ozone NAAQS. These are the days that 

EPA calculated HYSPLIT back trajectories as shown in Figure 5a of their DFW final NAA 

designations. The highest four daily maximum 8-hour ozone concentrations are highlighted in 

solid yellow. These top four exceedance days of each year are used to calculate the 8-hour ozone 

Design Value for the EMTL monitoring site that is used to determine whether the EMTL 

monitoring site violates the March 2008 ozone NAAQS. The three days that are identified as 

potentially representing the two back trajectories that intercept any part of Wise County (9/01/06, 
20

7/31/08 and 9/29/08)25

Table 2. Days during 2006-2008 that exceed the March 2008 ozone NAAQS at the EMTL 

monitoring site used in EPA’s HYSPLIT back trajectory analysis with days used in the calculation 

of the 8-hour ozone Design Values highlighted in solid yellow and days with back trajectories that 

potentially

are highlighted with diagonal shading in Table 2 and tend to be on the 

lower end of the concentration distribution. Table 2 shows that not only is it a rare occurrence 

that a back trajectory from the EMTL monitor on an exceedance day would intersect with Wise 

County, but when such an unusual event does occur, it occurs on an exceedance day that is so 

low that it is not used in the calculation of the EMTL ozone Design Value that determines 

whether the monitor is violating the ozone NAAQS.

26

2006

intersected with Wise County highlighted with diagonal shading.

Date

8-Hour

Ozone

2007

Date

8-Hour

Ozone

2008

Date

8-Hour

Ozone

2009

Date

8-Hour

Ozone

2010

Date

8-Hour

Ozone

20060614 107 20070814 121 20080804 98 20090625 100 20100604 94

20060609 106 20070815 101 20080618 92 20090605 92 20100827 91

20060628 98 20071004 86 20080623 86 20090626 92 20100828 83

20060718 98 20070725 84 20080619 85 20090826 92 20100529 81

20060612 95 20070922 84 20080722 81 20090702 91 20100917 81

20060618 92 20070812 81 20080808 80 20090813 89 20100826 80

20060719 92 20070920 80 20080826 80 20090806 84 20100811 78

20060630 88 20070921 80 20080907 80 20090627 82

20060818 88 20070923 79 20080701 79 20090707 82

20060720 87 20071012 79 20080814 78 20090903 80

20060821 87 20070724 78 20080928 78 20090520 79

20060615 86 20070827 78 20080731 77 20090521 77

20060629 85 20080920 77 20090717 77

20060707 85 20080929 77 20090823 77

20060603 84 20080927 76 20090906 77

20060608 84 20090519 76

20060721 84 20090701 76

20060831 83 20090822 76

20060613 82

20060708 82

20060914 82

20060901 81

20060907 81

20060724 80

20060908 80

20060701 78

20060819 78

20060610 77

20061008 77

20060605 76

 25 As discussed in Texas Pipeline Association’s comments at 33, it was not possible to identify which of two days 

correlated to one of the back trajectories passing over Wise County. Thus, the two possible days are included in this 

analysis. The result is that three days are examined above, whereas there were actually only two relevant back 

trajectories. 

26 As discussed in the previous footnote, three days are examined above, whereas there were actually only two 

relevant back trajectories. 
21

C.

Devon believes that the condensate storage tank VOC emissions rate that is reflected in 

the tons per year of VOCs attributed to Wise County in the Rule is artificially high and that EPA 

also must grant reconsideration in order to take a close look at the appropriate emissions factor to 

use for such emissions. The relatively high rate of estimated VOC emissions from Wise County 

compared to its population is one of the factors that EPA appeared to have cited to in making its 

final decision to list the county in nonattainment. Since the comment period on the Rule closed,

TCEQ has concluded that the emission factor should be corrected and has initiated a study to do 

exactly that. A corrected emission factor is likely to result in a significantly lower estimate for 

emissions from Wise County. This serves to further undermine the basis for listing Wise County 

as being in nonattainment. 

EPA must reconsider the Rule because new data demonstrates emissions 

from condensate storage tanks are likely much lower than reflected in the 

emissions estimates that EPA used

TCEQ’s new study is intended to develop updated county- and region-specific emission 

factors for estimating condensate storage tank emissions for each of the regions in Texas. These 

emissions are currently estimated using an emission factor from a 2006 Texas Environmental 

Research Consortium study entitled: “VOC Emissions from Oil and Condensate Storage Tanks,” 

also known as the HARC study.27

It is important to ensure that the emission factor for condensate storage tank emissions is 

correct because these tanks may be one of the biggest sources of VOC emissions from an oil and 

gas production sites. Flash emissions occur when produced liquid (crude oil or condensate) is 

exposed to pressure drops or temperature increases during transfer from pressurized production 

separators or similar sources into storage tanks at atmospheric pressure.

 TCEQ used this emission factor to develop county-level area 

source VOC emissions estimates from condensate tanks at upstream oil and gas operations, 

including an estimate for Wise County. In turn, EPA relied on TCEQ’s emissions estimate from 

Wise County as part of its basis for concluding that the county should be listed as being in 

nonattainment. Final DFW TSD at 6-9. 

28

There is strong reason to believe that the current estimate of flash emissions at oil and gas 

sites from the condensate tanks—the estimate relied upon by EPA—significantly overestimates 

emissions. Devon has concerns about the conditions and duration of testing that underlie the 

HARC study, as well as other flaws. In particular, there are significant statistical outliers in the 

dataset that was used to establish the HARC study emission factor. The removal of the two most 

egregious of those outliers would result in a reduction by half of the emission factor. Based on 

Devon’s on-the-ground experience and internal data, the likely emission factor should be much 

After examining those 

emissions, the HARC Study concluded that average VOC emission factor for condensate storage 

tanks is 33.3 pounds of VOC per barrel of liquid hydrocarbon produced (lb/bbl). 

 27 http://files.harc.edu/Projects/AirQuality/Projects/H051C/H051CFinalReport.pdf. 

28 http://www.tceq.state.tx.us/permitting/air/announcements/nsr_announce_9_30_09.html. 
22

lower than the HARC study results.29

Given the significant oil and gas production in Wise County, a reduction of the storage 

tank emission estimate should result in a significant reduction in the overall emission estimate 

for the county. As Table 3 indicates, over 80% of the estimated emissions from Wise County are 

from condensate production. Further, of all the nonattainment counties, Wise County’s total 

VOC emissions are the most influenced by emissions from condensate production. Therefore, a 

downward adjustment in the HARC emission factor would have the most significance for Wise 

County.

 Thus, Devon expects that TCEQ’s ongoing study will 

confirm a much lower estimate than the HARC study result. 

Table 3

County EPA 

TSD 

VOC

(tons)

% of tons VOC 

from 

Condensate 

(total)

2008 

Condensate

(Bbls)

Rockwall 2,047 0% 0

Kaufman 3,510 0% 0

Dallas 63,473 0% 0

Collin 14,503 0% 0

Tarrant 49,021 2% 57,008

Johnson 10,163 10% 59,214

Denton 24,932 31% 458,617

Parker 11,708 54% 380,805

Wise 17,609 84% 891,857

Now that TCEQ has recognized that the emission estimate is flawed and initiated a study 

to correct that emission estimate, EPA should reconsider whether to list Wise County as being in 

nonattainment. See Catawba County, 571 F.3d at 44-45 ( “EPA has an obligation to deal with 

newly acquired evidence in some reasonable fashion.”) (citation omitted). This new information 

indicates that Wise County’s actual emissions are likely much lower than the information EPA 

relied upon to issue the Rule. Devon understands that TCEQ intends to complete the study by 

the end of August. Thus, this should not delay the needed reconsideration by EPA. 

D.

EPA did not adequately justify or explain why it promulgated the specific regulations that 

it included in the final Rules, as it is required to do. See CAA § 307(d)(6)(A). The CAA requires 

EPA to provide “a response to each of the significant comments, criticisms, and new data 

submitted in written or oral presentations during the comment period.” See id. § 307(d)(6)(B). 

EPA’s responses on a number of issues raised by commenters were cursory at best and 

EPA failed to adequately respond to key comments

 29 Letter from Environ regarding Review and Analysis of HARC H51C Condensate Production VOC Emission 

Factor (May 16, 2011), attached as Attachment 1. 
23

nonexistent at worst. For example, EPA’s response to the complaint that EPA’s designation of 

Wise County is “inconsistent, and therefore arbitrary and capricious, when compared to the 

standards and methods of analysis that were applied in other States by other EPA Regional 

Offices” is to claim that the commenter “failed to point to any specific concerns to support its 

claim.” RTC at 58-59. Similarly, EPA claims a “fail[ure] to point to any specific circumstances 

that [a commenter] believes results in an inconsistency and therefore EPA cannot more specifically 

address the commenter’s concerns.” Id. at 61. EPA’s claims of lack of specificity somehow 

ignores the pages and pages of detailed specific examples of inconsistent treatment provided by 

the Texas Pipeline Association and others. See e.g., Texas Pipeline Association comments at 6-

11, 14-20. That information clearly demonstrates multiple specific examples of inconsistent 

treatment between EPA Regions. The following subsection also indentifies comments that EPA 

failed to respond to. 

E.

Devon and other commenters submitted many other reasons why EPA’s proposal to list 

Wise County as being in nonattainment is not warranted and not supported by the record. EPA 

failed to respond to some of these important comments. These reasons include: 

The comments already submitted amply demonstrate that Wise County 

should not be listed in nonattainment

• There is no correlation between increased Barnett Shale exploration and 

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

production, Design Values are generally down.30

• TCEQ has demonstrated through complex modeling that it is NOx, not man-made 

VOC that drives ozone formation in the DFW region. Their modeling concludes 

that elimination of 75% of man-made VOCs does little to reduce ozone 

concentration. Emissions from the Barnett Shale development are primarily 

VOCs, and further, the species of VOCs emitted by the oil and gas industry are 

straight chain alkanes and not the highly reactive VOC species (e.g. branched 

alkenes) that are linked to ozone formation.

 It does not appear that EPA 

ever responded to this comment. 

31

• The wind rose charts demonstrate that, on a yearly basis, the winds rarely blow 

into the DFW area from Wise County. TCEQ’s findings, demonstrate that “at 

most 2.87% of the trajectory endpoints from Wise County impact violating 

monitors.”

 It does not appear that EPA ever 

responded to these comments. See e.g., RTC at 55-56 (noting the comment, but 

offering no response). 

32

 30 See Texas Pipeline Association Comments at 28-29. 

31 See Devon comments at 4. 

32 Comments submitted by Mark Vickery, Executive Director, TCEQ (EPA–OAR–HQ–2008–0476-0296).
24

• Other EPA Regions have declined nonattainment designations based simply on 

prevailing winds. TSDs from various Regions continuously make generalized 

references to prevailing wind patterns, 30-year wind history, wind roses showing 

yearly average wind direction, and references to “predominant” wind direction. 33

Devon incorporates the prior comments of the Texas Pipeline Association, TCEQ and 

Devon, including but not limited to the comments summarized above, into these comments as 

part of the justification for why EPA should grant reconsideration and issue a stay. 

III.

A.

Grounds for stay

Pending reconsideration, the Administrator should stay the Rule as it applies to Wise 

County. Both the APA and CAA Section 307(d)(7)(B) authorize an administrative stay during 

reconsideration. Given the potential multi-million dollar impact of these regulations on industry 

in Wise County and the significance of the issues addressed above, justice and basic principles of 

good government require that EPA stay the Rules. 

A stay is warranted pursuant to both Section 307 of the CAA and Section 705 

of the APA 

EPA has broad authority and discretion to stay the effectiveness of rules promulgated 

under the CAA under both Section 307 of the CAA and Section 705 of the APA. The criteria 

that EPA must apply are significantly less stringent than the criteria generally used by the courts, 

for example, because a demonstration of irreparable harm is not mandatory:34

• First, CAA Section 307(d)(7)(B) provides that EPA may grant a stay if the Agency has 

decided to reconsider a rule. See 42 U.S.C. § 7607(d)(7)(B).35

• Second, “when justice so requires,” EPA may stay the effective date of a CAA rule 

pending judicial review, under Section 705 of the APA, 5 U.S.C. § 705.

 No other criteria or 

conditions are imposed on the Agency’s authority to issue a stay. 

36

 33 See Texas Pipeline Association comments at 8-10. 

 See, e.g., 

34 Nothing in the CAA requires a showing of irreparable harm in order to justify an administrative stay; instead, all 

that is required are proper grounds for reconsideration. The APA deliberately contrasts what is required for an 

administrative stay (“justice so requires”) and a judicial stay (“conditions as may be required” and “irreparable 

harm”). 5 U.S.C. § 705. Such differences must be given effect, and therefore there is no irreparable harm 

requirement for an administrative stay under the APA either.

35 CAA § 7607(d)(7)(B) provides, in relevant part:

If the person raising an objection can demonstrate to the Administrator that it was impracticable to raise 

such objection within such time or if the grounds for such objection arose after the period for public 

comment (but within the time specified for judicial review) and if such objection is of central relevance to 

the outcome of the rule, the Administrator shall convene a proceeding for reconsideration of the rule and 

provide the same procedural rights as would have been afforded had the information been available at the 

time the rule was proposed. ... The effectiveness of the rule may be stayed during such reconsideration, 

however, by the Administrator or the court for a period not to exceed three months.
25

Final Rule, Amendments of Final Rule To Postpone Requirements, 61 Fed. Reg. 28,508 

(June 5, 1996). 

Thus, the only express condition imposed on EPA’s authority to grant a stay under CAA 

§ 307 is that the Agency must have decided to reconsider the rule. APA § 705 is similarly broad, 

authorizing EPA to issue a stay: (1) if judicial review is pending; and (2) when “justice so 

requires.”37

A stay under § 307 is clearly warranted. As discussed above, the CAA Section 

307(d)(7)(B) standard for reconsideration is met, and it therefore follows that the standard for a 

stay under the CAA has similarly been met. In order to avoid the significant economic and 

social impacts—not just to Devon, but to the region and other impacts related to natural gas 

development in the county—of a rule that is arbitrary and should be reconsidered, justice 

requires that EPA grant the stay. 

 Of course, EPA also has the fundamental obligation to engage in reasoned decision 

making and must not make arbitrary and capricious determinations. All of these criteria leave 

EPA with considerable authority to stay the rules – especially under the current circumstances.

EPA’s authority to issue a stay under APA Section 705 is even broader than Section 307 

in two respects. First, 5 U.S.C. § 705 allows EPA to grant a stay “[r]egardless of whether [the 

stay request] meet[s] the requirements of Section 307(d)(7)(B).” See Ohio: Approval and 

Promulgation of Implementation Plans, 46 Fed. Reg. at 8,582 n.1. Second, EPA’s stay authority 

is not limited to three months. Furthermore, nothing in the CAA has abrogated EPA’s authority 

under § 705 of the APA. See, e.g., CAA § 7607(d)(1) (specifying sections of the APA that do 

not apply to CAA rulemaking, but not including APA § 705). EPA has regularly used this 

authority to “postpone”38

 36 APA § 705 reads: 

 the effective date of a rule indefinitely. See, e.g., Reconsideration of 

the Prevention of Significant Deterioration and Nonattainment New Source Review (NSR): 

Aggregation, 75 Fed. Reg. 27,643 (May 18, 2010); Final Rule, Amendments of Final Rule To 

Postpone Requirements, 61 Fed. Reg. 28,508 (June 5, 1996) (staying rules to prevent facilities 

from incurring “compliance expenditures . . . which may prove unnecessary in light of the 

projected amendments”); Hazardous Waste Management System: Identification and Listing of 

Hazardous Waste; Burning of Hazardous Waste In Boilers and Industrial Furnaces, 56 Fed. Reg. 

43,874 (Sept. 5, 1991).

When an agency finds that justice so requires, it may postpone the effective date of action taken by it, 

pending judicial review. On such conditions as may be required and to the extent necessary to prevent 

irreparable injury, the reviewing court, including the court to which a case may be taken on appeal from or 

on application for certiorari or other writ to a reviewing court, may issue all necessary and appropriate 

process to postpone the effective date of an agency action or to preserve status or rights pending conclusion 

of the review proceedings.

37 Devon intends to file a petition for review and anticipates that other petitions for review will likely be filed.

38 EPA can utilize the authority of APA § 705 either before, or after, the rules at issue have become effective. The 

plain meaning of the term “postpone” encompasses rules that are already in effect, just as a baseball game may be 

postponed after it has begun. 
26

B.

While a stay is warranted under the standards established by both the CAA and APA, it 

would be justified even under the more stringent standard employed by the courts. Courts 

typically consider four factors in determining whether to grant a judicial stay: “(1) whether the 

stay applicant has made a strong showing that he is likely to succeed on the merits; (2) whether 

the applicant will be irreparably injured absent a stay; (3) whether issuance of the stay will 

substantially injure the other parties interested in the proceeding; and (4) where the public 

interest lies.” Nken v. Holder, 129 S. Ct. 1749, 1761 (2009). These factors must be balanced 

against one another, such that “[a] stay may be granted with either a high probability of success 

and some injury, or vice versa.” Cuomo v. US Nuclear Reg. Comm’n, 772 F.2d 972, 974 (D.C. 

Cir. 1985). All four factors are amply satisfied in this case.

Even under the more stringent judicial standard, a stay is warranted

Failure to grant a stay will irreparably harm Devon. As discussed above, the 

incorporation of Wise County into the DFW nonattainment area would require Devon to make 

engine modifications, add additional control equipment and pay increased rental cost for leased 

compression to limit emissions from Devon’s compression fleet to 0.5 g NOx/hp-hr. Devon 

estimates that this would impose a compliance cost in excess of $18 million in the first year 

alone.39

The nonattainment designation would also put Devon’s E&P business at significant risk 

in future years. The lost net revenue on an enterprise wide basis could approach $17.2 million 

for every well that Devon would be prevented from drilling because of the regulations addressing 

the designation. For each well not drilled, Devon would not invest $2.95MM to support jobs and 

communities in Wise County. If Devon, for example, did not drill 25% of the remaining Wise 

County wells, the resultant decrease in revenue is estimated to be $4.3 billion. 

There are no offsetting harms to third-parties or the public interest from the narrow stay 

sought by Devon. To the contrary, these factors strongly favor a stay. There will be no harm to 

others, as Wise County is not contributing to violations of the NAAQS, as discussed above. 

Thus, staying the Rule as it applies to Wise County while EPA reconsiders the Rule will have 

little, if any, discernable environmental impact. By comparison, absent a stay, the harm to others 

beyond Devon will be significant. For every dollar of impact to Devon and other parties 

regulated under the rule, there will be a spillover impact to economic activity, taxes and jobs in 

the local region and the state. A recent study estimated the “2011 total effect of Barnett Shale 

activity to include $11.1 billion in annual output and 100,268 jobs in the region,” with the 

“majority of the stimulus com[ing] from exploration and drilling, pipeline development.”40

 39 Unrecoverable economic loss can amount to irreparable harm. See Thunder Basin Coal Co. v. Reich, 510 U.S. 

200, 220-21 (1994) (Scalia, J., concurring) (“[C]omplying with a regulation later held invalid almost always 

produces the irreparable harm of nonrecoverable compliance costs.”); Armour & Co. v. Freeman, 304 F.2d 404, 406 

(D.C. Cir. 1962) (“loss of profits which could never be recaptured” is irreparable harm).

The 

multiplier of this impact is significant, with “cumulative economic benefits during the 2001-2011 

40 The Perryman Group, A Decade of Drilling: The Impact of the Barnett Shale on Business Activity in the 

Surrounding Region and Texas: An Assessment of the First Decade of Extensive Development (Aug. 2011) 

(available at http://www.fortworthchamber.com/BarnettShaleStudy11.pdf). The report notes that Wise County is one 

of the primary areas of activity.
27

period include[ing] $65.4 billion in output (gross product) and 596,648 person-years of 

employment in the region.”41 Further, the state would lose significant tax revenue, impacting 

publicly provided services. Finally, as President Obama has recognized, there is a strong public 

interest in natural gas production, as it provides “jobs and ... economic benefits to the entire 

domestic production supply chain, as well as to chemical and other manufacturers, who benefit 

from lower feedstock and energy costs” and it “reduce[s] our dependence on oil,” as well as 

“provid[ing] a cleaner source of energy than other fossil fuels.”42

IV.

Any action that reduces the 

development of this important resource will harm jobs, the local and regional economies and the 

promotion of gas as a critical and environmentally favorable alternative to coal. The balance of 

harms and public interest, thus, clearly favor granting a stay. 

For the foregoing reasons, the Administrator must convene a proceeding for 

reconsideration of the Rule and stay the Rule pending reconsideration.

Conclusion

Respectfully submitted,

Timothy K. Webster

_______________________

SIDLEY AUSTIN, LLP

1501 K Street, N.W.

Washington, D.C. 20005

(202) 736-8000 (phone)

(202) 736-8711 (facsimile)

Counsel to

Devon Energy Corporation 

Attachment 1 - Letter from Environ regarding Review and Analysis of HARC H51C Condensate 

Production VOC Emission Factor (May 16, 2011). 

 41 Id. at 4. 

42 Executive Order, Supporting Safe and Responsible Development of Unconventional Domestic Natural Gas 

Resources (Apr. 13, 2012).
28

Attachment 1
May 16, 2011 

Mr. Grover Campbell 

Manager Regulatory Affairs – Air Regulations 

Chesapeake Energy Corporation 

Oklahoma City, OK 73154-0496 

Re: Review and Analysis of HARC H51C Condensate Production VOC Emission Factor 

Dear Mr. Campbell: 

As requested by Chesapeake Energy Corporation (“Chesapeake”), ENVIRON has performed a 

technical review of the October 31, 2006, report prepared by URS Corporation (“URS”) entitled 

“VOC Emissions From Oil and Condensate Storage Tanks” (hereafter referred to as the “HARC 

H51C Report”).1

 Following is a summary of ENVIRON’s review specifically related to the 

derivation of the 33.3 lb VOC/bbl emission factor. 

As presented within the HARC H51C Report, average VOC emission factors were derived from 

emission tests conducted on 21 tank batteries.2

 Figure 1 shows the relationship between the 

estimated VOC emission factor and production rate for these 22 sites.3

 As shown, 9 test sites 

had condensate production of less than 5 bbl/day.4

Derived tank battery-specific VOC emission factors ranged from 0.7 lb/bbl to 215.1 lb/bbl. 

Figure 1 presents the relationship between condensate production and estimated VOC emission 

factor for the 21 condensate storage tank batteries used by URS in the derivation of the VOC 

emissions as a function of condensate production emission factor. 

For this data set, the mean VOC emission factor was 33.3 lb/bbl with a standard deviation of 

53.3 lb/bbl.5

 As can be seen from Figure 1, there are two sites with much higher VOC emission 

factors compared to the other sites. These two sites are denoted with red diamonds. The 

emission factors and condensate production rates for these two sites are: 

• 215.1 lb/bbl at a production rate of 1 bbl/day, and 

• 145.1 lb/bbl at a production rate of 2 bbl/day. 

 

1 http://files.harc.edu/Projects/AirQuality/Projects/H051C/H051CFinalReport.pdf

2

 Results from testing conducted at a 22nd site, Tank Battery 26 with a derived emission factor of 1,218 

lb/bbl, was discarded from the analysis with the reason given that the vent gas flow rate measurement 

was taken during non- representative conditions. Per the HARC H-51C Report, for Tank Battery 26, 97 

percent of the measured vent gas was released during the first 8 hours of the 24-hour sampling period. 

The report attributed this condition to fracking at an adjacent well. 

3

 Detailed HARC H-51C data is presented in Attachment A of this review. 

4

 Based on our review of the report, it is our understanding that production rates were not measured 

during testing. Rather, URS requested and obtained production estimates from operators at a later date. 

5

 The standard deviation, which is the variation around the mean, is approximately 1.6 times the mean for 

this data set, indicating high variability in the data. When the standard deviation exceeds the mean, it can 

imply that the data set is either too small to accurately determine the true mean value and/or there may 

not be a strong relationship between the two variables considered. Caution should be exercised when 

using a mean value derived from this data set. 
Mr. Grover Campbell - 2 - May 16, 2011 

Chesapeake Energy 

Figure 1. VOC Emission Factor as a Function of Condensate Production, 

Excluding Tank Battery 26 

(Derived from HARC H51C Report) 

To put these values into context: 

• Condensate production of 1 bbl/day is equal to approximately 22.4 teaspoons per minute 

of condensate production. In other words, a fast drip. 

• A production rate of 5 bbl/day is equal to about 18.7 fluid ounces per minute. At that 

rate, on average, it would take about 39 seconds to fill a 12 ounce soft drink can. 

• A typical condensate storage tank is 12 feet in diameter with a cross-sectional area of 

approximately 113 ft2

. Adding 5 barrels to a tank of this size will raise the liquid level in 

the tank approximately 3 inches. 

• Assuming a condensate specific gravity of 0.70, a barrel of condensate weighs 

approximately 245 lbs. An emission rate of 215.1 lb/bbl means that, on a mass basis, 

nearly as much VOC is being emitted as is being collected and recovered. Note that 

VOC already excludes emissions of methane and ethane. 

Based on ENVIRON’s experiences in managing tank testing programs as well as observations 

provided by natural gas liquids producers, making accurate measurements of condensate 

production at very low production levels is problematic. 

Presented as Figure 2 is a “box-and-whisker” plot of the 21 data points used in deriving the 33.3 

lb/bbl VOC emission factor. The box-and-whisker plot is a useful way of depicting observations 

graphically and also to identify outliers. The lower and upper limits of the central gray box 

represent the 25th and 75th percentiles, also known as the lower and upper quartiles of the data. 

The thin white band within the gray box is the median of the data. The red diamond is the mean 

of the data. The ‘whiskers’ (short horizontal end cap lines) represents the lower and the upper 

extreme quartiles. The red circles represent data points that are at least 3 times the difference 

between the upper and lower quartiles (also called the intra-quartile range) above (or below) the 

median. Statistically, these red circles are “outside outliers.” “Inside outliers are data points that 

0

50

100

150

200

250

300

0 20 40 60 80 100 120 140 160

VOC Emission Factor (lb/bbl)

Condensate Production (bbl/day)

Condensate Production, 5 bbl/day

Emission Factor, 145.1 lb VOC/bbl

Emission Factor, 215.1 lb VOC/bbl
Mr. Grover Campbell - 3 - May 16, 2011 

Chesapeake Energy 

are more than 1.5 times but less than 3.0 times the inter-quartile range above (or below) the 

median. 

Figure 2. Box-and-Whisker Plot for All Data Points Used in 

Deriving 33.3 lb/bbl Emission Factor 

(Derived from HARC H51C Report)

The two red circles in Figure 2 representing 215.1 lb VOC/bbl and 145.1 lb VOC/bbl emission 

factors for Tank Batteries 25 and 17, respectively, are outside outliers and, most likely, should 

be excluded from the analysis. 

If the outside outliers identified in Figure 2 are excluded from the data set, the average VOC 

emission factor is 17.9 lb/bbl with a standard deviation of 19.5 lb /bbl. By excluding these two 

outliers, the standard deviation becomes smaller relative to the mean: 1.1 times the mean 

versus 1.6 times the mean when these two data points are not excluded. Therefore, the data 

shows better agreement when these two data points are excluded. 

As noted, it is difficult to obtain accurate measurements of condensate production at low levels. 

If 5 bbl/day is used as the threshold for making reasonably accurate measurements of 

condensate production, then eight of the sites used in deriving the 33.3 lb/bbl emission factor 

should be excluded from the analysis. Figure 3 presents the relationship between VOC 

emission factor and condensate production for the 13 sites with measured production rates 

greater than or equal to 5 bbl/day. 

The mean VOC emission factor for this data set is 13.8 lb VOC/bbl with a standard deviation of 

18.3 lb VOC/bbl (1.3 times the mean). While showing less variability than the data set 

presented in Figure 1, the data shown in Figure 3 does demonstrate variability due to the three 

points shown as red diamonds. 

0

50

100

150

200

250

VOC Emission Factor (lb/bbl)

Outliers
Mr. Grover Campbell - 4 - May 16, 2011 

Chesapeake Energy 

Figure 3. VOC Emission Factor as a Function of Condensate Production, 

Tank Batteries with Production ≥ 5 bbl/day 

(Derived from HARC H51C Report) 

Figure 4 is a box-and-whisker plot for derived VOC emission factors for 13 tank battery sites 

with condensate production greater than or equal to 5 bbl/day. As explained earlier in this 

summary, the box-and-whisker plot is a useful way of identifying outliers. The red circle in 

Figure 4 is an outside outlier. This represents the derived VOC emission factor for Tank Battery 

32. The red stars in Figure 4 are inside outliers. The two stars represent the derived VOC 

emission factors for Tank Batteries 20 and 29. 

Figure 4. Box-and-Whisker Plot for Derived VOC Emission Factors, 

Tank Batteries with Production ≥ 5 bbl/day 

(Derived from HARC H51C Report)

0

10

20

30

40

50

60

70

0 20 40 60 80 100 120 140 160

VOC Emission Factor (lb/bbl)

Condensate Production (bbl/day)
Mr. Grover Campbell - 5 - May 16, 2011 

Chesapeake Energy 

If the one site identified as an outside outlier in Figure 4 is excluded from the data set, the 

average VOC emission factor is 9.6 lb/bbl with a standard deviation of 11.0 lb /bbl. By excluding 

this one data point, the standard deviation becomes smaller relative to the mean: 1.1 times the 

mean versus 1.3 times the mean when this data point is not excluded. Therefore, the data 

shows better agreement when this data point is excluded. 

If, in addition to the one outside outlier, the two inside outliers are excluded from the analysis, 

the average VOC emission factor is 5.1 lb/bbl with a standard deviation of 3.5 lb /bbl. By 

excluding these three points, the standard deviation becomes smaller relative to the mean: 0.7 

times the mean versus 1.1 times the mean when just the outside outlier is excluded. 

Note that, in this statistical analysis, the lowest derived emission factors – Tank Batteries 4 and 

5 at 0.78 and 0.67 lb VOC/bbl, respectively – are not outliers. Thus, it is would not be 

appropriate to exclude them from the analysis. 

A standard deviation lower than the mean indicates that the data are closely grouped around 

the mean. Assuming a “normal” distribution, 68% of the tank battery sites would have a VOC 

emission factor within one standard deviation of the mean and 95% of the tank battery sites 

would have a VOC emission factor within two standard deviations of the mean. Only the last 

data set considered exhibits a “normal” distribution.6

Table 1 presents a statistical analysis of various datasets presented in this review. 

Table 1. VOC Emission Factors – Statistical Analysis 

Dataset 

No. 

Number of Tank 

Battery Sites 

Condensate 

Production 

(bbl/day) 

Mean VOC 

Emission Factor 

(lb VOC/bbl) 

Standard 

Deviation 

(lb VOC/bbl)

1ba 21 All 33.3 53.3 

1cb 19 All 17.9 19.5 

3a 13 ≥ 5 13.8 18.3 

3bc 12 ≥ 5 9.6 11.0 

3bd 10 ≥ 5 5.1 3.5 a Original HARC H51C data set. 

b

 Original data set excluding the two outside outliers. 

c

 Condensate production ≥ 5 bbl/day, excluding the one outside outlier. d Condensate production ≥ 5 bbl/day, excluding the one outside and two inside outliers. 

For comparative purposes, the Colorado Department of Public Health and Environment 

(“CDPHE”) recommends VOC emission factors that range from 3.0 lb VOC/bbl to 13.7 lb 

VOC/bbl, for condensate storage tanks, depending on the location of the facility.7,8 

 

 

6

 This data set consists of 10 tank batteries: 2, 3, 4, 5, 6, 15, 18, 23, 28 and 30. 

7 http://www.cdphe.state.co.us/ap/sbap/SBAPoilgastankguidance.pdf

8

 CDPHE recommends that these emissions factors should only be used if the total uncontrolled VOC 

emissions due to condensate tanks at the site are less than 80 tons per year. CDPHE recommends sitespecific sampling and analysis to estimate emissions for sites having uncontrolled VOC emissions greater 

than 80 tons per year. 
Mr. Grover Campbell - 6 - May 16, 2011 

Chesapeake Energy 

It should be noted that of the 21 tank batteries used in deriving the 33.3 lb VOC/bbl emission 

factor, 10 of the sites were operating at a separator discharge pressure of approximately 200 

pounds per square inch (“psi”), one was operating at a discharge pressure of approximately 121 

psi, and the remaining 10 sites were all operating at pressures of less than 50 psi. Instead of 

deriving a single emission factor, in ENVIRON’s opinion, it may have been more appropriate to 

derive two emission factors: one for “high pressure” separation and one for “low pressure” 

separation. 

Using the 3b dataset (condensate production ≥ 5 bbl/day, excluding the one outside and two 

inside outliers), derived emission factors for “high pressure” separators (operating at 

approximately 200 psi or greater) and “low pressure” separators (operating at less than 50 psi) 

are as follows. 

• “High Pressure” Separators: 

- Data points = 3 

- Mean VOC Emission Factor = 16.6 lb/bbl 

- Standard Deviation = 12.2 lb/bbl 

• “Low Pressure” Separators: 

- Data points = 7 

- Mean VOC Emission Factor = 4.0 lb/bbl 

- Standard Deviation = 2.5 lb/bbl 

While these data subsets most likely have an insufficient number of test data points to 

accurately derive emission factors (especially for the high pressure separator subset), it is 

interesting to note that these subsets show better data correlation than do any of the larger 

datasets. For the low pressure separator data subset, the standard deviation is 0.6 times the 

mean. As previously noted, for the 3b dataset as a whole, the standard deviation is 0.7 times 

the mean. 

 

Please let us know if you have any questions. 

Best Regards, 

Steven H. Ramsey, P.E., BCEE Shagun Bhat, PhD 

Principal Consultant Senior Associate 
Attachment A: 

HARC H51C Report Site Data 
Tank 

Battery County Area

Separator 

Discharge 

Pressure (psi)

API 

Gravity

Condensate 

Production 

(bbl/day)

Der

Emiss

(

2 Montgomery Houston-Galveston-Brazoria 41 42 105 3 Montgomery Houston-Galveston-Brazoria 38 41 87 4 Montgomery Houston-Galveston-Brazoria 34 40 120 5 Montgomery Houston-Galveston-Brazoria 46 43 100 6 Montgomery Houston-Galveston-Brazoria 33 39 130 

13 Denton Dallas-Fort Worth ~200 61 2 14 Denton Dallas-Fort Worth ~200 59 4 15 Denton Dallas-Fort Worth ~200 61 5 16 Denton Dallas-Fort Worth ~200 61 2 17 Denton Dallas-Fort Worth ~200 58 2 18 Denton Dallas-Fort Worth ~200 58 10 19 Denton Dallas-Fort Worth ~200 58 2 20 Denton Dallas-Fort Worth ~200 59 10 23 Parker Dallas-Fort Worth 39 48 27 24 Parker Dallas-Fort Worth 36 41 1 25 Denton Dallas-Fort Worth ~200 58 1 227 Denton Dallas-Fort Worth ~200 59 2 28 Brazoria Houston-Galveston-Brazoria 38 46 30 29 Brazoria Houston-Galveston-Brazoria 41 42 61 30 Brazoria Houston-Galveston-Brazoria 36 42 15 32 Galveston Houston-Galveston-Brazoria 121 48 142 

(Derived from HARC H-51C Report)

Attachment A

Tank Battery Sites