BEFORE THE UNITED STATES

ENVIRONMENTAL PROTECTION AGENCY

TREASURE STATE RESOURCE 

INDUSTRY ASSOCIATION

and

YELLOWSTONE COUNTY, A 

POLITICAL SUBDIVISION OF 

THE STATE OF MONTANA

Petitioners,

In the Matter of: Air Quality 

Designations for the 2010 Sulfur 

Dioxide (SO2) Primary National 

Ambient Air Quality Standard

78 Fed. Reg. 47,191 (Aug. 5, 2013)

EPA Docket #: EPA–HQ–OAR–

2012–0233

PETITION FOR RECONSIDERATION OR REPEAL OF A PORTION OF 

THE FINAL RULE AND REQUEST FOR AN ADMINISTRATIVE STAY 

PENDING AGENCY PROCEEDINGS

William W. Mercer

Emily C. Schilling

Marie Bradshaw Durrant

HOLLAND & HART, LLP

222 South Main, Suite 2200

Salt Lake City, UT 84101

wwmercer@hollandhart.com

ecschilling@hollandhart.com

mbdurrant@hollandhart.com

Counsel for the Treasure State 

Resource Industry Association

Daniel L. Schwarz

YELLOWSTONE COUNTY 

ATTORNEY’S OFFICE

217 N. 27th Street, Room 207

P.O. Box 35025

Billings, MT 59107-5025

Yellowstone County Chief Civil 

Deputy County Attorney
i

TABLE OF CONTENTS

Introduction .....................................................................................................................................1

Factual Background.........................................................................................................................2

Argument.........................................................................................................................................4

I. This Petition is Based on New Information that is of Central Relevance to 

the Outcome of the Rule..........................................................................................4

II. Newly Available Air Quality Data for Yellowstone County Clearly 

Demonstrate Attainment for Yellowstone County. .................................................6

a. The most recent block of three-year monitoring data after the 

effective date of the SO2 NAAQS demonstrate design values well 

below 75 ppb. ..............................................................................................6

b. The New Data underscore the arbitrary nature of EPA’s conclusion 

that 2010 data are representative of the air quality in Yellowstone 

County. ........................................................................................................8

III. The Nonattainment Process Is Unnecessary to Achieve the 2010 SO2

NAAQS or Protect Public Health............................................................................9

IV. The New Data Further Call into Question the Pre-Effective Date Data 

from the Coburn Road Monitor.............................................................................12

a. The 1996 MDEQ QAPP was inadequate and inappropriate to 

ensure the collection of reliable, high-quality measurements for the 

more stringent 2010 SO2 NAAQS.............................................................14

b. The Coburn Road monitor did not meet strict quality assurance 

requirements for the 2009-2011 data set. ..................................................17

c. The New Data were collected after the operating range for the 

Coburn Road monitor was adjusted to more reliably collect data 

for the 2010 SO2 NAAQS. ........................................................................21

d. Similarly, the New Data were collected after the 2010 SO2

NAAQS was in effect, allowing for more appropriate attention to 

outliers and transient monitoring malfunctions for the 75 ppb 

standard......................................................................................................22

e. The New Data provide additional evidence that 2010 data do not 

represent the air quality in Yellowstone County. ......................................23

V. The New Data Were Gathered with the 2010 SO2 NAAQS Appropriately

In Effect. ................................................................................................................25

VI. EPA Should Stay the Yellowstone County Portion of the Rule............................28

VII. Conclusion.............................................................................................................31
1

INTRODUCTION

On August 5, 2013, the Environmental Protection Agency (EPA) issued the final rule 

titled “Air Quality Designations for the 2010 Sulfur Dioxide (SO2) Primary National Ambient 

Air Quality Standard,” (National Nonattainment Designations or Rule),1 which designated as 

nonattainment a portion of Yellowstone County, Montana (Yellowstone SO2 Designation). 

Treasure State Resource Industry Association (TSRIA), a Montana trade association whose 

mission is to promote and advocate for responsible natural resource development and reasonable 

environmental regulation in Montana,2and Yellowstone County, MT, a political subdivision of 

the State of Montana (together, Petitioners), submit this petition to EPA pursuant to section 

307(d)(7)(B) of the Clean Air Act (CAA)3and section 553(e) of the Administrative Procedure 

Act (APA) (the Petition).4 The Petition focuses narrowly on the Yellowstone SO2 Designation 

and requests that EPA (1) reconsider and repeal the Yellowstone SO2 Designation based on new 

data demonstrating that no portion of Yellowstone County should have been designated 

nonattainment for the 2010 SO2 NAAQS; and (2) stay the Yellowstone SO2 Designation pending 

completion of EPA’s administrative proceedings.5 This petition incorporates by reference, and 

supplements, the petition for reconsideration submitted to EPA by Montana Sulphur & Chemical 

Company (MSCC) on October 4, 2013.6

 

1

78 Fed. Reg. 47,191 (Aug. 5, 2013).

2 TSRIA’s member companies in Yellowstone County include PPL Montana, LLC, which owns and operates the 

J.E. Corette coal-fired power plant, as well as Phillips 66 and ExxonMobil, which own and operate petroleum 

refineries, Yellowstone Energy Limited Partnership, which owns and operates a petroleum coke-fired power plant, 

and Montana Sulphur & Chemical Company, which owns and operates a gas processing and fertilizer plant.

3

42 U.S.C. § 7607(d)(7)(B).

4

5 U.S.C. § 553(e).

5 TSRIA also has filed a petition for review of EPA’s Yellowstone SO2 Designation in the U.S. Court of Appeals for 

the District of Columbia Circuit, which was consolidated with other petitions for review as Sierra Club v. EPA (D.C. 

Cir. No. 13-1262, 13-1263, 13-1264).

6 MSCC, Petition for Reconsideration: Air Quality Designations for the 2010 Sulfur Dioxide (SO2) Primary 

National Ambient Air Quality Standard, Yellowstone County, Montana (Oct. 4, 2013), EPA-HQ-OAR-2012-0233-

0356.
2

FACTUAL BACKGROUND 

On June 22, 2010, EPA promulgated a primary SO2 NAAQS of a one-hour SO2

concentration of 75 ppb, based on the three-year average of the 99th percentile (or annual fourth 

highest) one-hour daily maximum concentrations (2010 SO2 NAAQS).7 The secondary SO2

standard of a three-hour concentration of 500 ppb remained in place and provides the closest 

comparable federal standard to the new 75 ppb standard for purposes of measuring ambient SO2

concentrations over short averaging times. Pursuant to Section 107(d) of the CAA, no later than 

one year from promulgation of a new standard, states are required to submit initial designations 

of all areas of the state to EPA as either attainment, nonattainment, or unclassifiable.8 On May

27, 2011, the state of Montana (State) timely submitted its initial designations to EPA, including 

a designation of unclassifiable for the entirety of Yellowstone County.9 

In August 2012, EPA exercised its conditional authority under the CAA to extend by one 

year the final promulgation of initial area designations for the 2010 SO2 NAAQS on grounds the 

Agency had “insufficient information to promulgate the designations.”10 EPA published notice 

of its proposed designations on February 15, 2013, and requested comment on those 

designations.11 EPA proposed to designate as nonattainment 30 areas where available 

monitoring data from 2009 through 2011 indicated violations of the one-hour SO2 NAAQS.12 

 

7 EPA, Primary National Ambient Air Quality Standard for Sulfur Dioxide, 75 Fed. Reg. 35520 (June 22, 2010). 

8

42 U.S.C. § 7407(d)(1)(A). 

9 Montana State-Wide Sulfur Dioxide (S02) NAAQS Designations, Letter from Richard H. Opper, Director MDEQ 

on behalf of Governor Brian Schweitzer to EPA Region 8 (May 27, 2011).

10 42 U.S.C. § 7407(d)(1)(B)(i). EPA, Extension of Deadline for Promulgating Designations for the 2010 Primary 

Sulfur Dioxide National.

Ambient Air Quality Standard, 77 Fed. Reg. 46,295 (Aug. 3, 2012); 

11 EPA, EPA Responses to State and Tribal 2010 Sulfur Dioxide Designation Recommendations: Notice of

Availability and Public Comment Period, 78 Fed. Reg. 11,124 (Feb. 15, 2013).

12 Id. at 11,126. 
3

One of those areas was the entirety of Yellowstone County, Montana.13 EPA stated that it was 

not prepared to designate the remainder of the country, or seek related comment thereon, and 

would “address those areas in a subsequent round or multiple rounds of responses and 

designations.”14 

A coalition of interested parties, including TSRIA, submitted comments to EPA opposing 

the Yellowstone County designation on grounds that: (1) EPA relied on non-representative data 

that do not accurately portray the air quality in Yellowstone County; (2) EPA used data that do 

not strictly comply with EPA regulatory requirements; and (3) EPA relied on air quality data 

obtained before the new SO2 NAAQS became effective (TSRIA Comments).15 The State also 

submitted comments reasserting that the entirety of Yellowstone County should be designated 

unclassifiable and that the SO2 monitoring data collected in the Billings area during 2010 should 

not be used to designate Yellowstone County as nonattainment.16 The statutory deadline of June 

22, 201317 for EPA to promulgate all initial designations passed without EPA action.18 On 

August 5, 2013, EPA published the Rule, which designates as nonattainment a portion of 

Yellowstone County surrounding PPL Montana’s J.E. Corette coal-fired power plant (Corette).19 

 

13 EPA excluded areas of Indian country associated with the Crow reservation from the proposed Yellowstone 

County nonattainment area. Jim Martin, EPA Region 8 Administrator letter to Steve Bullock, Governor of 

Montana, regarding EPA’s proposed designation of Yellowstone County as nonattainment, Ref: 8P-AR (Feb. 6, 

2013), Docket EPA-HQ-OAR-2012-0233-0198.

14 78 Fed. Reg. at 11,124.

15 See Comments from Montana Petroleum Association, Treasure State Resource Industry Association, and Billings 

Laurel Air Quality Technical Committee to EPA (Apr. 8, 2013), Docket EPA-HQ-OAR-2012-0233-0285.

16 Steve Bullock, Governor of Montana, Letter to EPA Region 8 Regarding EPA’s Proposed Montana Sulfur 

Dioxide (S02) NAAQS Designations, April 3, 2013. Under threat of EPA’s proposed county-wide designation, and 

registering due protest, the State also submitted an alternative five-factor analysis in case EPA again rejected its 

proposed unclassifiable designation.

17 See CAA § 107(d)(1)(B)(i); 42 U.S.C. § 7407(d)(1)(B)(i) (“the Administrator shall promulgate the designations of 

all areas . . . in no case later than 2 years from the date of promulgation of the new or revised national ambient air 

quality standard. Such period may be extended for up to one year in the event the Administrator has insufficient 

information to promulgate the designations.”).

18 Because EPA did not act by this deadline, technically the area should have retained the unclassifiable designation 

made by the State.

19 78 Fed. Reg. at 47,202.
4

The majority of the United States, however, remained undesignated; EPA stated that it was “not 

yet prepared to issue designations” and would address these designations in “separate future 

actions . . .”20

ARGUMENT

I. This Petition is Based on New Information that is of Central Relevance to the 

Outcome of the Rule.

Petitioners request that EPA reconsider and repeal the Yellowstone SO2 Designation 

based on new information that became available after the close of the public comment period, is 

of central relevance to the outcome of the Rule, and supports a repeal of the Designation.21 

Specifically, Yellowstone County, Montana, presents a unique case, and the new data 

demonstrate that it should not have been included in the National Nonattainment Designations 

for the following reasons: (1) the air quality in Yellowstone County does not exceed the 2010 

SO2 NAAQS; (2) sufficient permanent and enforceable controls are in place to assure continued 

attainment, making the requirements for a nonattainment State Implementation Plan (SIP) and a 

redesignation process unnecessary; (3) EPA’s design value alleging exceedance of the 2010 SO2

NAAQS falls within the measurement margin of error and was based on unrepresentative and 

unreliable data; and (4) by relying on data gathered after the effective date of the 2010 SO2

NAAQS Rule, EPA can avoid problems associated with retroactive application of the Rule. 

These new data and information, set forth in greater detail below, arose after the close of the 

public comment period and before the deadline for judicial review and therefore appropriately 

form the basis for reconsideration under section 307(d)(7)(B) of the CAA and a proceeding to 

repeal the Yellowstone Designation under section 553(e) of the APA. 

 

20 Id. at 47,193.

21 42 U.S.C. § 7607(d)(7)(B). See also 5 U.S.C. § 553(e). 
5

Pursuant to section 307(d)(7)(B) of the CAA, reconsideration is appropriate where it was 

“impracticable to raise” a particular objection within the comment period, 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 . . . .”22 

The statute does not specify a deadline by which such a petition must be submitted, as long as 

the grounds for the objection arose (1) after the conclusion of the public comment period, but (2) 

within the 60-day period specified for judicial review.23 In this case, the Petition is based on 

monitoring data and related information that are central to the outcome of the Yellowstone SO2

Designation and occurred after the close of the public comment period but prior to the October 4, 

2013 deadline for judicial review of the Rule. 

Furthermore, EPA has a duty to respond to this Petition pursuant to general principles of 

administrative law. As set forth in Oljato, “the public’s right to petition the Administrator . . . 

and the Administrator’s duty to respond substantively to such requests exist completely

independently of Section 307 . . .”24 Section 553(e) of the APA requires an agency to provide 

“an interested person the right to petition for the issuance, amendment, or repeal of a rule.”25 

When presented with a petition under section 553(e) of the APA, “an agency is required to at 

least definitely respond . . .”26 This petition raises substantive new data and information that 

form compelling grounds for repeal of the Yellowstone SO2 Designation.

The Clean Air Act directs the Administrator to base NAAQS designations on the State’s 

initial designation as well as “air quality data, planning and control considerations, or any other 

 

22 42 U.S.C. § 7607(d)(7)(B).

23 Id. See also Oljato Chapter of the Navajo Tribe v. Train, 515 F.2d 654, 660 (D.C. Cir. 1975) (“new information” 

that comes to light in the period after the end of the comment period may “dictate a revision or modification of any 

promulgated standard or regulation established under the act.”) (citing S. Rep. No. 91-1196, 91st Cong., 2d Sess., 

41-42 (1970)). 

24 Oljato v. Train, 515 F.2d at 667. 

25 5 U.S.C. § 553(e). 

26 Friends of the Earth v. EPA, 934 F. Supp.2d 40, 54 (D.D.C. 2013) (citations omitted). 
6

air quality-related considerations the Administrator deems appropriate . . . .”27 The information 

outlined below provides EPA with compelling air quality data, planning and control 

considerations, and other air quality-related considerations to reconsider and repeal the 

Yellowstone SO2 Designation.

II. Newly Available Air Quality Data for Yellowstone County Clearly Demonstrate 

Attainment for Yellowstone County.

The results of monitoring gathered after the effective date of the Rule verify that the air 

quality in Yellowstone County complies with the 2010 SO2 NAAQS (New Data).28 These air 

quality data demonstrate attainment pursuant to CAA § 107(d)(1)(A)(ii) and demonstrate that 

EPA’s Yellowstone SO2 Designation was in error and should be reconsidered and repealed. 

EPA therefore should provide the same procedural rights and consideration of the New Data as 

would have been granted had the information been available at the time the rule was proposed 

and initiate administrative proceedings to reconsider and repeal the Yellowstone SO2

Designation.29

a. The most recent block of three-year monitoring data after the effective date 

of the SO2 NAAQS demonstrate design values well below 75 ppb.

The New Data provide the first three-year block of monitoring data since August 23, 

2010, the effective date of the 2010 SO2 NAAQS.30 This full three-year data set, on which 

Petitioners base this Petition, was not complete until after the close of the comment period on 

 

27 See CAA § 107(d)(3)(A); 42 U.S.C. § 7407(d)(3)(A). While this sub-section of the CAA pertains to 

redesignation, these considerations apply equally to promulgation of initial designations under Section (d)(1)(A) and 

(B), which require that an area “meets the national primary . . . ambient air quality standard for the pollutant” and 

allows the Administrator discretion as “necessary” and as long as it is not “inappropriate.” CAA § 107(d)(1)(B)(ii); 

42 U.S.C. § 7407(d)(1)(B)(ii).

28 The new results will be validated early next year. EPA has traditionally used full calendar years of validated data 

for comparison with the NAAQS. Validation will verify the significance of the New Data and can only decrease the 

final concentration values by eliminating invalid high readings. No increase in the magnitude of the readings is 

possible with validation.

29 42 U.S.C. § 7607(d)(7)(B); 5 U.S.C. § 553(e).

30 See 75 Fed. Reg. 35520, 35520. 
7

April 8, 2013, and therefore Petitioners could not raise the data during the comment period.31 

The first three-year block of New Data after the effective date (September 1, 2010 through 

August 31, 2012) was gathered prior to the October 4, 2013 deadline for judicial review and 

demonstrates attainment of the 2010 SO2 NAAQS.32 The chart below illustrates the latest data 

available from the Montana Department of Environmental Quality (MDEQ), with the 99th 

percentile value for 2013 based on data through November 3, 2013.33 Petitioners plan to submit 

monthly data updates to EPA as they become available through the end of the 2013 calendar 

year, including final validated data.

 

31 See EPA, EPA Responses to State and Tribal 2010 Sulfur Dioxide Designation Recommendations: Notice of 

Availability and Public Comment Period, 78 Fed. Reg. 17,915, 17,916 (Mar. 25, 2013).

32 Data was obtained from EPA, Air Data, available at www.epa.gov/airdata. 

33 Data after September 30, 2013, were obtained from an MDEQ email from Stephen Coe to James Parker regarding 

Coburn Info (Nov. 6, 2013) (included in Attachment A).
8

In addition to demonstrating attainment, the New Data confirm State and stakeholder 

assertions that the 2009-2011 data that EPA relied on to make the nonattainment designation 

were unreliable, nonrepresentative, and not in accordance with the law.34 In addition, the New 

Data verify the State’s conclusion that the air quality in Yellowstone County complies with the 

2010 SO2 NAAQS and a nonattainment designation is unnecessary. Expert analysis of these 

data, performed by consultants for TSRIA,35 establishes that Yellowstone County is attaining the 

2010 SO2 NAAQS and provides further evidence that a nonattainment designation was 

improperly applied to Yellowstone County. 

A more detailed presentation of the monitoring results and associated analyses are 

included as Attachment A. The New Data provide EPA with compelling and lawful grounds to 

reconsider and repeal the Yellowstone SO2 Designation.

b. The New Data underscore the arbitrary nature of EPA’s conclusion that 

2010 data are representative of the air quality in Yellowstone County.

In addition, the New Data are of central relevance to the outcome of the Rule because 

they provide further evidence that EPA’s reliance on 2010 data to make the Yellowstone SO2

Designation resulted in the erroneous designation of a portion of Yellowstone County as 

nonattainment. 

In the Technical Support Document (TSD), EPA reached the flawed and unreasonable 

conclusion that “the 2009 and 2011 emissions appear to be below past emissions levels, while 

2010 data appear more representative of emissions.”36 EPA reached this conclusion by

comparing 2010 emissions to 2008 emissions (which reflect a time period prior to 

implementation of federally enforceable controls discussed in the State and TSRIA Comments) 

 

34 See, e.g., TSRIA Comments, Docket EPA-HQ-OAR-2012-0233-0285. 

35 Bison Engineering, Inc. provided the analyses in Attachments A and B.

36 EPA, Technical Support Document: Montana Area Designations for the 2010 SO2 Primary National Ambient Air 

Quality Standard, July 25, 2013, at 10.
9

and ignoring 2012 data presented by the State and other commenters, even though EPA 

acknowledged possessing and analyzing 2012 data.37 EPA also failed to consider 2010 in 

isolation from surrounding years, as requested by the State and industry, and chose instead to 

consider only consecutive three-year averages, which extend the unrepresentative effects of 2010 

from 2008 through 2011.38 In essence, EPA’s TSD and Response to Comments (RTC) ignore 

the State’s request to take account of additional data showing that 2010 data do not represent the 

air quality of Yellowstone County based on faulty reasoning and incomplete comparisons. 

Rather than using unrepresentative data, EPA should evaluate Yellowstone County’s 

designation based on the New Data, which are more current, representative, and reliable, and 

appropriately reflect air quality during a time period after the effective date of the 2010 SO2

NAAQS.

III. The Nonattainment Process Is Unnecessary to Achieve the 2010 SO2 NAAQS or 

Protect Public Health.

The New Data confirm that the requirements for a nonattainment area in Yellowstone 

County are unnecessary to protect public health. Furthermore, an unnecessary nonattainment 

designation would waste valuable time and divert essential personnel resources of MEDQ and 

EPA, entail superfluous and expensive control technologies for industry in Yellowstone County, 

and subject sources within Yellowstone County to costly and overly predictive modeling 

requirements.39 Even taking into consideration the provisions outlined in EPA’s recently

released draft “Clean Data” policy,

40 the processes to demonstrate attainment as well as the 

 

37 See, e.g., EPA, Responses to Significant Comments on the State and Tribal Designation Recommendations for the 

2010 Sulfur Dioxide National Ambient Air Quality Standards, July 2013, Docket No. EPA-HQ-OAR-2012-0233, at 

52-53. 

38 See, e.g., EPA TSD at 8-9.

39 See, e.g., Dana Wood and Doug Blewitt, Are EPA Regulatory Models Capable of Providing Accurate Estimates 

of Future Air Quality? at 6, presented at EPA 10th Conference on Air Quality Modeling (Mar. 13-15, 2012), 

available at http://www.epa.gov/ttn/scram/10thmodconfpres.htm (last visited Nov. 25, 2013).

40 See EPA, Draft Guidance for 1-Hour SO2 Nonattainment Area SIP Submissions, at 45-52 (Oct. 28, 2013).
10

requirements for redesignation and maintenance plans involve the same concerns of “overregulation,” costs, and modeling. These planning and control considerations are relevant to 

EPA’s designation process, as set forth in Section 107(d)(3)(A) of the CAA, and weigh in favor 

of a finding that the Yellowstone SO2 Designation should be reconsidered and repealed. 

Based on the Yellowstone SO2 Designation, MDEQ is now required to develop a 

nonattainment SIP and may be required to develop costly and controversial modeling before the 

nonattainment sanction can be removed.41 As EPA itself recognizes, “There are serious political, 

economic and health consequences of making . . . decision errors [for a NAAQS designation].”42 

The New Data provide further evidence of the documented downward trend of SO2 emissions 

and concentrations over the past several years and the effectiveness of the numerous enforceable 

controls that are having, and will continue to have, a substantial effect on SO2 levels in 

Yellowstone County. As argued extensively in the State’s initial designation and subsequent 

comments, a nonattainment designation is “inappropriate” and “not necessary.”43 

The NAAQS are designed with an adequate margin of safety to protect public health.44 

The concept of a nonattainment area, and the stringent requirements tied to a nonattainment 

designation, are only intended to address the public health concerns for an area “that does not 

meet . . . the national primary . . . ambient air quality standard for the pollutant.”45 If an area is 

in compliance with the NAAQS, as Yellowstone County is, control requirements designed to 

 

41 See id.

42 EPA, Quality Assurance Handbook for Air Pollution Measurement Systems, Vol. II (Ambient Air Quality 

Monitoring Program) § 3.0, EPA-454/B-08-003 (Dec. 2008) (hereinafter “EPA QA Handbook”).

43 See, e.g., Montana State-Wide Sulfur Dioxide (S02) NAAQS Designations, Letter from Richard H. Opper, 

Director MDEQ on behalf of Governor Brian Schweitzer to EPA Region 8, at 24-25, May 27, 2011; see also Steve 

Bullock, Governor of Montana, Letter to EPA Region 8 regarding EPA’s Proposed Montana Sulfur Dioxide (S02) 

NAAQS Designations, April 3, 2013.

44 See, e.g., 42 U.S.C. § 7409(b)(1); Whitman v. Am. Trucking Associations, 531 U.S. 457, 476 (2001).

45 CAA § 107(d)(1)(A)(i); 42 U.S.C. § 107(d)(1)(A)(i).
11

surpass the NAAQS “would be both costly and unnecessary.”46 Requiring MDEQ to develop a 

nonattainment SIP and reduce Yellowstone County’s SO2 emissions, create on-going 

maintenance plans, and apply for redesignation (which may require expensive and controversial 

modeling) are meaningless yet costly procedural hurdles for an area already attaining the 

NAAQS. 

Moreover, existing and future planning and control considerations support the 

reconsideration and repeal of the Yellowstone SO2 Designation.47 SO2 emissions have declined 

dramatically in Yellowstone County over the past three decades.48 The control requirements 

already in place for SO2 emission sources in Yellowstone County, as well as several required 

future federal controls that will be implemented over the next several years, ensure that the air 

quality in Yellowstone County will only continue to improve.49 As the New Data demonstrate, 

Yellowstone County is already achieving the 2010 SO2 NAAQS with the emission controls 

currently in place, providing far more certainty for public health than other areas of the U.S. 

where EPA has postponed designations with no reliable basis for assessing attainment.

EPA identified Corette as the “key contributor” to past high readings at the Coburn Road 

monitor.50 However, PPL has demonstrated its commitment to SO2 reductions in the future. 

PPL has announced that it will mothball Corette in 2015,51 and any reopening is contingent upon 

 

46 Sierra Club v. U.S. E.P.A., 99 F.3d 1551, 1556 (10th Cir. 1996).

47 42 U.S.C. § 7407(d)(3)(A).

48 See TSRIA Comments at 2, Docket EPA-HQ-OAR-2012-0233-0285.

49 See State Initial Designation at 19-24 for a full treatment of existing and projected future control requirements that 

will continue to bring down SO2 emissions in Yellowstone County; see also TSRIA Comments at 4-8.

50 See EPA, Technical Support Document: Montana Area Designations For the 2010 SO2 Primary National 

Ambient Air Quality Standard, July 25, 2013, at 13-14.

51

 See, e.g., PPL Montana News, 

http://www.pplmontana.com/news/archived+news/2013/September/PPL+Montana+reaches+agreement+to+sell+hyd

roelectric+facilities.htm?WBCMODE=Pre (last visited Nov. 21, 2013).
12

compliance with the federal Mercury and Air Toxic Standard (MATS)52 and may decrease SO2

emissions by a further 10%.53 PPL also entered into a consent decree with MDEQ in 2013 to 

reduce SO2 emissions by 60%.54 The consent decree was finalized just after the close of public 

comments for the Yellowstone SO2 Designation but before promulgation of the Rule. The 

consent decree becomes effective upon designation of Yellowstone County as unclassifiable for 

the 2010 SO2 NAAQS and based on Corette’s continued operation as an “electric utility steam 

generating unit” as defined under 40 C.F.R. § 63.10042 on or after the MATS compliance 

deadline of April 16, 2015.55 Thus, if Yellowstone County is ultimately designated 

unclassifiable, the Corette plant will contribute further SO2 reductions for an area already 

achieving the 2010 SO2 NAAQS. 

The combination of demonstrated attainment and the promise of further dramatic future 

SO2 reductions highlight the futility of the Yellowstone SO2 Designation. Because no health 

protections are gained by the nonattainment designation—which introduces real and substantial 

economic harm—reconsideration and repeal of the Yellowstone SO2 Designation is in the public 

interest. 

IV. The New Data Further Call into Question the Pre-Effective Date Data from the 

Coburn Road Monitor.

The New Data also are of central relevance to the outcome of the Rule because they

confirm stakeholder concerns about the quality and reliability of pre-effective date data from the 

Coburn Road monitor. EPA relied on data from a monitor that did not meet EPA’s high 

 

52 EPA, National Emission Standards for Hazardous Air Pollutants From Coal- and Oil-Fired Electric Utility Steam 

Generating Units and Standards of Performance for Fossil-Fuel-Fired Electric Utility, Industrial-CommercialInstitutional, and Small Industrial-Commercial-Institutional Steam Generating Units77 Fed. Reg. 9304 (Feb. 16, 

2012).

53 See TSRIA Comments at 8.

54 Montana v. PPL Montana, No. DV 12-1546 (Mont. 13th Jud. Dist. May 31, 2013) (consent decree). 

55 Id.
13

standards for comparison with the NAAQS.56 EPA also failed to respond to comments 

documenting that the monitoring organization did not strictly comply with its own and EPA’s 

quality assurance requirements during this period.57 

Because Yellowstone County is in a unique situation, even minor deviations and quality

lapses call the data into question and could impact the designation outcome. The quality and 

technical accuracy of the Coburn Road monitor before the Rule’s effective date did not meet 

public and stakeholder expectations to ensure the monitoring results accurately reflect the 

ambient air quality in Yellowstone County.

58

 EPA’s design value (79 ppb) for the Yellowstone 

SO2 Designation is only 4 ppb above the 2010 SO2 NAAQS, meaning the difference between 

attainment and nonattainment falls within the uncertainty range of the Coburn Road monitor.59 

Because the magnitude of the Coburn Road monitor’s alleged exceedance of the 2010 SO2

NAAQS falls within the margin of error for the monitor—meaning the difference between 

attainment/unclassifiable and nonattainment is within the margin of error—strict compliance 

with quality control and monitoring standards becomes even more important to ensure 

reasonable public and stakeholder confidence in the final designation. Thus, EPA should 

reconsider and repeal the nonattainment designation, taking into account the New Data and 

 

56 See, e.g., 40 C.F.R. §§ 50, 53, and 58 (outlining EPA monitoring requirements); Lisa Jackson, EPA 

Administrator, EPA Response to Petition for Reconsideration from Earthjustice, Dec. 14, 2012, available at 

http://www.epa.gov/airquality/ozonepollution/designations/2008standards/petition/respEarthJustice.pdf (hereinafter 

EPA WEG Response) (rejecting a request to use monitoring data to make a nonattainment designation because the 

monitors did not meet EPA regulatory standards); EPA, Draft Technical Support Document: Iowa Area 

Designations for the 2010 SO2 Primary National Ambient Air Quality Standard, at 3 (detailing how data collected 

while the “regulatory” monitor was experiencing calibration problems cannot be used for nonattainment designation 

purposes), available at http://www.epa.gov/so2designations/region7r.html (last accessed Nov. 21, 2013); General 

Motors Corp. v. Costle, 631 F.2d 466, 468 (6th Cir. 1980) (upholding EPA’s rejection of third party monitoring data 

because of inadequate quality assurance).

57 See Attachment to Comments from Montana Chemical & Sulphur Company at 14-25 (May 13, 2013), Docket 

EPA-HQ-OAR-2012-0233-0298; TSRIA Comments at 13-16, Docket EPA-HQ-OAR-2012-0233-0285.

58 40 C.F.R. § 58, App. A § 2.1.

59 The margin of error for the Coburn Road monitor has been calculated to range from -10 ppb to +7 ppb. See 

Attachment to Comments from Montana Chemical & Sulphur Company at 22 (May 13, 2013), Docket EPA-HQOAR-2012-0233-0298; TSRIA Comments, at 18, n. 56 (citing Billings Laurel Air Quality Technical Committee 

(BLAQTC), SO2 Designation: Analysis and Recommendation For Billings/Laurel, Montana, April 5, 2011, at 22).
14

giving adequate consideration to the impact of existing and future emission controls on 

continued attainment of the SO2 NAAQS. The New Data provide assurance that public health 

will not be jeopardized while EPA completes a designation based on more reliable data that is 

representative of air quality in Yellowstone County. 

a. The 1996 MDEQ QAPP60 was inadequate and inappropriate to ensure the 

collection of reliable, high-quality measurements for the more stringent 2010 

SO2 NAAQS.

The 1996 MDEQ Quality Assurance Project Plan (1996 QAPP), the governing Statelevel document for the Coburn Road monitor when the 2009-2011 data were collected, was not 

sufficient to meet EPA’s requirements for “regulatory” monitors for the 2010 SO2 NAAQS. The 

QAPP requirements themselves – even if precisely adhered to – were developed for the 500 ppb 

3-hour standard. Draft QAPP updates were prepared in 2005 and 2009, but were never issued as 

formal documents. The more recent draft quality requirements do not differ greatly from the 

1996 QAPP, as discussed in Attachment B. In the EPA RTC, EPA did not address TSRIA 

arguments that the 1996 QAPP governing Coburn Road was inadequate for determining 

nonattainment of the 2010 SO2 NAAQS.61 Although EPA provided audit levels for the Coburn 

Road monitor in the RTC, EPA did not respond to the specific deficiencies identified in the 

QAPP.

EPA claims that the Coburn Road monitor meets the necessary requirements to be a

“regulatory” monitor that can measure compliance with the 2010 SO2 NAAQS: 

Montana DEQ has an approved Quality Management Program and 

EPA routinely conducts Technical Systems Audits of Montana’s 

monitoring program. The State has provided all the necessary 

information to show that the data that has been reported, including 

 

60 MDEQ, Quality Assurance Project Plan: Montana Ambient Air Monitoring Program (Nov. 1, 1996).

61 See EPA RTC, at 49-50, Docket No. EPA-HQ-OAR-2012-0233.
15

the data it decided to invalidate, follows the guidelines specified 

above.62

And yet, EPA also defines monitors that do not have an adequate QAPP as “non-regulatory”: 

Since the Rayonier monitoring data was not collected using an 

EPA approved Quality Assurance Project Plan, the data do not 

meet the quality assurance requirements of 40 CFR Part 58.63

EPA appears to assume that, once approved by EPA, a QAPP is adequate to make a monitor 

“regulatory” regardless of its contents or the monitoring organization’s compliance with the 

QAPP. However, this does not satisfy EPA’s own regulations. The QAPP “must”:

ensure that the monitoring results:

(a) Meet a well-defined need, use, or purpose;

(b) Provide data of adequate quality for the intended monitoring objectives;

(c) Satisfy stakeholder expectations;

(d) Comply with applicable standards specifications;

(e) Comply with statutory (and other) requirements of society; and

(f) Reflect consideration of cost and economics.64

The MDEQ QAPP in place when the Coburn Road data were gathered was approved by

EPA in 1996.65 Draft updates were prepared in 2005 and 2009, but neither was ever finalized 

and issued as a formal, EPA-approved document.66 Therefore the 1996 QAPP was legally in 

effect when the 2009-2011 data were gathered by the Coburn Road monitor. At the federal level, 

the December 2008 version of EPA’s Quality Assurance Handbook (EPA QA Handbook)67 was 

in effect at the time the 2009-2011 Coburn Road data were collected. Obviously the 1996 QAPP 

 

62Id. at 44.

63 Id. at 18; see also id. at 34-36 (rejecting results from the Valero monitor because it does not meet Part 58 

standards), 50 (explaining that ozone monitors from the Uinta Basin in Utah lacked an adequate QAPP and thus 

could not be considered “regulatory” monitors). See also EPA WEG Response.

64 40 C.F.R § 58, App. A, § 2.1.

65 MDEQ confirms that “[t]he 2013 QAPP [currently under review] is the first revision since the issuance of the 

Montana QAPP in 1996.” MDEQ, Montana Ambient Air Monitoring Program Quality Assurance Project Plan, Vol. 

1: Continuous Monitor, Filter-Based Sampler, and Meteorological Sensor Requirements for Monitoring Ambient 

Air § 4.4, April 15, 2013.

66 MDEQ, Quality Assurance Project Plan, Montana Ambient Air Monitoring Program, Draft, Vol. 1, April 2005 

(MDEQ QAPP 2005); MDEQ, Montana Ambient Air Monitoring Program, Quality Assurance Project Plan, Volume 

1, Draft, March 2009 (MDEQ QAPP 2009).

67 EPA, Quality Assurance Handbook for Air Pollution Measurement Systems, Vol. II (Ambient Air Quality 

Monitoring Program), EPA-454/B-08-003, December, 2008.
16

did not contain updated information reflecting either the December 2008 EPA QA Handbook 

requirements or the 2010 SO2 NAAQS.

The 1996 QAPP utilized by MDEQ for the Coburn Road monitor does not meet EPA’s 

requirements in relation to measuring the 2010 SO2 NAAQS. The 1996 QAPP contains 

standards, suggested range levels, and monitoring guidance specific to the less stringent 500 ppb 

measurement goal.68 The 1996 QAPP obviously does not address the new 75 ppb standard. 

However, the 1996 QAPP, despite its flaws and irrelevance to the 75 ppb standard, does contain 

definitive data collection requirements. As discussed in sub-section IV.b below, these definitive 

requirements were not consistently complied with by MDEQ. It is arbitrary and capricious for 

EPA to justify using data from the Coburn Road monitor while rejecting other monitors, such as 

the Rayonier monitor, based on the assumption that the 1996 QAPP provided better quality 

assurance for the Coburn Road monitor. While an outdated QAPP may be sufficient when 

readings do not surpass a standard (given the fact that quality assurance only serves to invalidate 

high readings rather than to add missed high readings), in a close call such as the Yellowstone 

SO2 Designation, an outdated QAPP is unacceptable. The 1996 QAPP is not sufficient to make 

the Coburn Road monitor “regulatory” for purposes of a nonattainment designation for the 2010 

SO2 NAAQS of 75 ppb. 

EPA itself emphasizes that the QAPP should include standard procedures and monitoring 

methods:

The QAPP is a formal document describing, in sufficient detail, the 

quality system that must be implemented to ensure that the results 

of work performed will satisfy the stated objectives.69

 

68 See, e.g., MDEQ QAPP § 12.2.1 (outlining audit range levels); § 9.5.4 (zero/span/precision check levels); § 15.3 

(operational control limits).

69 40 C.F.R. Part 58, App. A § 2.1.2; see also EPA WEG Response § III.
17

The 1996 QAPP, like other “non-regulatory” QAPPs, is insufficient to meet the standards 

outlined in Part 58 in relation to the 2010 SO2 NAAQS.70

b. The Coburn Road monitor did not meet strict quality assurance 

requirements for the 2009-2011 data set.

In addition to the inadequacies of the MDEQ QAPP, the Coburn Road Monitor was not 

operated in strict accordance with the QAPP and failed to meet quality assurance requirements 

for the 2009-2011 data. In addition, corrective action was not taken as required to address 

certain monitoring deficiencies. EPA failed to address concerns about MDEQ quality assurance 

practices documented in comments submitted to EPA.71 EPA requires both adherence to the 

QAPP and corrective action when monitoring deficiencies are identified before data may be used 

for a NAAQS designation.72 The MDEQ QAPP requires both immediate corrective action and 

reports to document that action.73 The MDEQ QAPP identifies minimum data quality

requirements for all ambient monitoring conducted by MDEQ. The State requirements must be 

at least as stringent as federal requirements.74

As noted above, the 1996 MDEQ QAPP – even if strictly observed – did not address 

compliance with the 2010 SO2 NAAQS. A third-party examination of Coburn Road data 

disclosed numerous instances of non-compliance with the 1996 QAPP requirements.75 In 

support of this petition, the Coburn Road data was examined in depth with an emphasis on data 

quality indicators associated with the fifteen high (≥ 75 ppb) SO2 readings observed from 2009 –

 

70 See EPA WEG Response § III (“The QAPP prepared for the nonregulatory Uinta Basin monitors . . . are not 

complete enough to allow the EPA to determine that the data are appropriate for determining that a violation of the 

NAAQS has occurred for designations purposes.”).

71 See, e.g., Attachment to Comments from Montana Chemical & Sulphur Company at 14-25 (May 13, 2013), 

Docket EPA-HQ-OAR-2012-0233-0298; TSRIA Comments, at 13-16, Docket EPA-HQ-OAR-2012-0233-0285.

72 40 C.F.R. § 58, App. A § 1.2; see also 40 C.F.R. § 58, App. C, §§ 1.0 and 2.1; EPA, QA Handbook §§ 1.3.2 and 

10.0. 

73 See, e.g., MDEQ QAPP §§ 4.0(B), 15.2 and 15.3(A).

74 40 C.F.R. § 58, App. A § 1 (outlining federal requirements as “minimum quality system requirements” and 

encouraging states “to develop and maintain quality systems more extensive than the required minimums.”).

75 See, e.g., Attachment to Comments from Montana Chemical & Sulphur Company at 14-25 (May 13, 2013), 

Docket EPA-HQ-OAR-2012-0233-0298.
18

2011.76 Nine of these readings occurred in 2010 alone and constitute the entire justification for 

the Yellowstone SO2 Designation.

While numerous factors affect data quality, the expert evaluation presented here focuses 

on quantitative, numerical indicators that can be easily compared to unambiguous requirements 

and performance specifications given in the 1996 MDEQ QAPP and EPA guidance documents 

relied on by MDEQ to guide data collection activities. Three primary data quality assurance 

activities were analyzed, representing the foundation of any regulatory ambient data collection 

program:

1. Performance Checks, often referred to as zero/span/precision (ZSP) checks. They

involve challenging the SO2 analyzer with zero air and two non-zero known gas 

concentrations and evaluating the instrument’s response. If one or more responses fall 

outside prescribed limits, immediate corrective action is required to bring analyzer 

responses back to within designated acceptable limits. These checks must be performed 

successfully once every two weeks.77

2. Multipoint Calibrations, which involve adjusting the analyzer response to obtain 

accurate responses to clean (or “zero”) air, plus at least four known gas concentrations 

in specified ranges. The QAPP requires these calibrations once every 90 days at a 

minimum.78

3. Quality Assurance Audits are independent checks of instrument performance by a 

person not involved in operation of the analyzer, using separate calibration standards. 

They are similar to multipoint calibrations, except that no adjustments are made. The 

 

76 See Attachment B with analysis from Bison Engineering, Inc.

77 MDEQ QAPP 1996 §§ 9.8.4 (A) and 15.3(B); see also EPA QA Handbook, SO2 Validation Template, App. D at 

9.

78 MDEQ QAPP 1996 § 9.8.7.
19

analyzer is challenged at a “zero” concentration, plus at least three known gas 

concentrations in specified ranges. If any result exceeds specific performance limits, 

immediate investigation into the causes and subsequent corrective action are required.79

Table 1 summarizes and briefly describes the eight data quality issues identified among 

the fifteen high SO2 readings occurring from 2009 – 2011. A more in-depth discussion of the 

data quality evaluation, including specific references for each evaluation criterion, is presented in 

Attachment B to this document. For each high reading shown in the leftmost column, an “X” is 

used to identify each data quality lapse associated with that reading. Each “X” indicates that a 

particular data quality indicator (one or both activities bracketing the high reading) did not 

comply with one or more specific QAPP requirements. For example, on July 8, 2010 the “X” in 

the column labeled “Performance Check Results” indicates that one or both of the surrounding 

performance checks (which were conducted on June 28 and July 12, as shown in Attachment B) 

produced results exceeding a control limit or warning limit, and that no subsequent corrective 

action was taken (which should have occurred, per the QAPP80). Similarly, the “X” in the 

column labeled “Calibration Gas Ranges” indicates that one or both of the calibrations 

(conducted on April 15 and August 23) did not include all four of the non-zero gas concentration 

ranges prescribed by the QAPP. When such quality assurance lapses occur at an industry

continuous emission monitor, an enforcement action may result, including fines and invalidation 

or substitution of the data.81 Attachment B provides specific information regarding the exact 

results constituting non-compliance with the QAPP.

 

79 MDEQ QAPP 1996 § 12.2.1(B)

80 MDEQ QAPP 1996 §§ 4.0(B), 15.2 and 15.3(A).

81 See, e.g., Montana v. PPL Montana, No. DV 12-1546 (Mont. 13th Jud. Dist. May 31, 2013) (consent decree), 

(asserting that a failure to ensure the appropriate reviews of the QAPP jeopardized data meant to demonstrate 

compliance with SO2 emission limits).
20

TABLE 1 – SUMMARY OF COBURN ROAD DATA QUALITY ISSUES DURING HIGH 

(≥ 75 ppb) SO2 READINGS82

Date

SO2

Conc.

(ppb)

Perform.

Check

Interval 

(1)

Perform.

Check

Results 

(2)

Calibrat.

Interval 

(3)

Calibrat.

Gas

Ranges 

(4)

Calibrat.

Results 

(5)

Audit

Gas

Ranges 

(6)

Audit

Results 

(7)

Audit

Gas

Cylinder 

(8)

2009

Feb 5 83 X X

Sep 22 107 X X

Sep 25 83 X X

2010

Feb 10 91 X X

July 8 111 X X X X X

July 9 92 X X X X X

Sep 26 78 X

Sep 28 83 X

Oct 2 75 X

Oct 3 87 X

Oct 22 89 X X

Dec 24 101 X

2011

Sep 5 142 X X

Sep 11 113 X X

Oct 30 85 X X

Key to Data Quality Issues Associated with Reading in Question

(1) Performance checks not conducted at required 2-week interval

(2) Performance check result(s) exceeding warning limit or control limit, with no subsequent 

corrective action

(3) Calibrations not performed at required 90-day interval

(4) Calibration not performed at required number of non-zero concentrations

(5) Calibration results exceeded acceptance limit, with no subsequent corrective action

(6) Performance audit not conducted at required gas concentrations

(7) Performance audit result exceeded acceptance limit, with no subsequent corrective action

(8) Audit gas cylinder certification was expired at time of audit 

From Table 1 and supporting information presented in Attachment B, it is evident that 

each of the fifteen daily maximum SO2 readings at or above 75 ppb has at least one data quality

non-conformance issue associated with it. In general, at least one of the following occurred:

1. At least one of the data quality assurance activities occurring before or after the high 

reading produced results exceeding QAPP-specified limits, with no subsequent 

corrective action; 

 

82 The information in Table 1 is the result of Bison Engineering’s review and analysis of ambient and quality 

assurance data from MDEQ, obtained from various comments and appendices in MDEQ’s general records. 
21

2. At least one of the quality assurance activities was not performed as specified in the 

QAPP; or

3. At least one of the quality assurance activities was not performed at the frequency

specified by the QAPP.

The MDEQ QAPP contains very specific minimum requirements, frequencies and acceptance 

ranges for each quality assurance activity. Because the data are the sole basis for the 

Yellowstone SO2 Designation and fall within the margin of error, and because the Designation 

has such sweeping, long-term impacts, it is reasonable to demand that the data quality assurance 

strictly comply with QAPP specifications.

c. The New Data were collected after the operating range for the Coburn Road 

monitor was adjusted to more reliably collect data for the 2010 SO2 NAAQS.

The New Data were all gathered after the operating range of the Coburn Road monitor 

was adjusted from a setting intended to measure the old 3-hour 500 ppb standard to one more 

appropriate for the 2010 SO2 1-hour 75 ppb standard. The range settings in place on the Coburn 

Road monitor were not appropriately configured for the 2010 SO2 NAAQS until mid-August 

2010. The inappropriate operating range introduced a higher potential for precision problems for 

measurements at or near the 2010 SO2 NAAQS for the 2009-2011 data, particularly data 

gathered prior to the August 2010 adjustment. As documented in the TSRIA Comments and 

Attachment B, the higher span range introduced significant concern about the accuracy of the 

2009-2011 data.83 The New Data are not subject to these same concerns.

 

83 See TSRIA Comments at 14-16.
22

d. Similarly, the New Data were collected after the 2010 SO2 NAAQS was in 

effect, allowing for more appropriate attention to outliers and transient 

monitoring malfunctions for the 75 ppb standard.

Concerns about outlier data, as expressed in the TSRIA Comments,84 are considerably 

lessened for the New Data. EPA regulations appropriately require monitoring organizations to 

ensure monitors “[m]eet a well-defined need, use, or purpose” and “[s]atisfy stakeholder 

expectations.”85 Stakeholders expressed considerable concerns about how outliers from the 75 

ppb standard could be properly addressed before the standard was even in place.86 The New 

Data were collected after the 75 ppb standard was in place, when readings above 75 ppb would 

attract appropriate attention, allowing more timely and thorough analysis. 

With the tight margins for the Yellowstone SO2 Designation, even one mistaken high 

concentration outlier could lead to a faulty nonattainment designation if unnoticed and 

uncorrected. Several cases of transient problems were detected by MDEQ itself before 2011. 

However, the QAPP guidance in place at the Coburn Road monitor through 2010 were not 

designed to routinely detect, identify, and correct possible outlier events in relation to the 2010 

SO2 NAAQS of 75 ppb. Thus invalid data around 75 ppb, such as high concentration outliers, 

would likely go unnoticed and appear valid in the record because the QAPP and standard 

practices did not require specific checks for readings near the 75 ppb level. Situational 

occurrences that might contribute to outliers, such as someone burning weeds nearby, would be 

nearly impossible to identify years after the fact. EPA failed to address stakeholder concerns 

about outlier data in the EPA RTC.87

 

84 See id. at 15-16; see also MDEQ 2005 QAPP, Vol. 1, § 21.2.

85 40 C.F.R. § 58, App. A § 2.1(a) and (c).

86 See TSRIA Comments at 15-16.

87 EPA RTC, at 50, Docket No. EPA-HQ-OAR-2012-0233.
23

e. The New Data provide additional evidence that 2010 data do not represent 

the air quality in Yellowstone County.

The 99th percentile daily maximum 2010 value of 91 ppb at Coburn Road is the only 

value that pulls EPA’s 2009-2011 design value above the 2010 SO2 NAAQS. The New Data 

further support the State’s conclusions that the extreme 2010 readings from the Coburn Road 

monitor do not represent the air quality in Yellowstone County. The higher 2010 readings from 

Coburn Road are inconsistent with both 1) readings from the Coburn Road monitor in adjacent 

years, and 2) maximum readings from surrounding monitors during 2010. The 1996 QAPP 

identifies several techniques for screening air quality and meteorological data, including 

“Comparison with Existing Spatial or Temporal Fields:” 

Screening data by comparison with fields of similar or related data 

is commonly done when large amounts of data are taken and when 

assumptions of the spatial continuity of the meteorological or 

pollutant variable are physically reasonable. Fields of data in time, 

rather than space, are also used to check data points.88

The 2010 maximum daily concentration data from the Coburn Road monitor differ 

substantially from data in preceding and subsequent years. As reported above, the most recently

available data from the Coburn Road monitor through November 3, 2013, clearly demonstrate 

attainment of the 2010 SO2 NAAQS. This supports the downward trend asserted by the State 

and illustrated in the chart below. The 99th percentile SO2 readings from 2010 differ 

significantly from the surrounding years, which show compliance with the 2010 SO2 NAAQS. 

SO2 emissions have declined dramatically since 2008, in part due to federally enforceable 

controls that have and will continue to be implemented.89

 

88 1996 QAPP § 15.4(B)(3).

89 See State Initial Designation at 19-24 for a full treatment of existing and projected future control requirements that 

will continue to bring down SO2 emissions in Yellowstone County; see also TSRIA Comments at 4-8.
24

Yellowstone County is a highly monitored area and has several air quality monitors in the 

same general area as the Coburn Road monitor. As shown in the chart below, the Coburn Road 

monitor is the only monitor in Yellowstone County with averaged 1-hour peak readings for 2010 

even slightly above the 2010 SO2 NAAQS. Coburn Road is generally recognized as the “high 

concentration” monitor for Yellowstone County based on years of past results and empirical 

evidence.90 It is a source-oriented monitor placed near stack-height for nearby upwind sources. 

Other monitors presently operating in the county are also source-oriented.

 

90 See, e.g., A Summary of Historical Ambient SO2 Monitoring in the Billings Area, a report prepared for BillingsLaurel Air Quality Technical Committee (BLAQTC) by Bison Engineering, Inc. (Feb. 9, 2013).
25

A qualified third-party inspection questioned use of the 2010 data from the Coburn Road 

monitor as the sole basis for the Yellowstone SO2 Designation: 

The Coburn readings for 2010 climbed inexplicably in the same 

year as other monitors continued to decline. This occurs under the 

same emissions and climatic conditions. All other monitors in the 

county show unequivocal compliance with the standard. This 

unexpected behavior at only one monitor is unexplained by

emissions or meteorology, and therefore begs further study before 

a reasonable determination (other than unclassifiable) can be 

made.91

The New Data are more representative of the air quality in Yellowstone County and confirm that 

the 2010 data should not form the basis for the Yellowstone SO2 Designation.

V. The New Data Were Gathered with the 2010 SO2 NAAQS Appropriately In Effect.

Finally, the New Data were gathered after the effective date of the 2010 SO2 NAAQS and 

therefore do not suffer from the same defects as 2009-2011 data set, the use of which result in 

retroactive application of the standard. 

 

91 Billings Laurel Air Quality Technical Committee. SO2 Designation: Analysis and Recommendation for 

Billings/Laurel, Montana, April 5, 2011, at 3. 

78

70

50

67

63 62

0

10

20

30

40

50

60

70

80

90

Coburn Rd Johnson Lane Brickyard Lockwood

(2008-2010)

Laurel Pines Hills

(2008-3Q10)

S

O2 P

P

B

Billings Area SO2 Monitors 3-yr Average Design Value 2010-2012
26

EPA has decided not to make 2010 SO2 NAAQS designations for any areas other than 

nonattainment areas at this time.92 Because of the unique nature of Yellowstone County, with a 

design value that falls within the margin of error for the monitor and comparable temporal and 

spatial data showing attainment, EPA’s identified need for more time to make effective and 

accurate 2010 SO2 NAAQS designations93 should apply equally to Yellowstone County. 

Instead, EPA relies on data from before the 2010 SO2 NAAQS was even effective and gives no 

weight to information provided by the State and industry that the 2009-2011 data, especially

2010, are not adequately reliable and do not represent the air quality in Yellowstone County. 

EPA should reconsider and repeal the Yellowstone SO2 Designation and allow Yellowstone 

County time to assemble appropriate data, just as it has for other potentially unclassifiable areas 

under the Next Steps plan. This approach would avoid the problems of retroactive application of 

the 2010 SO2 NAAQS as described in the TSRIA Comments and others.94 Again, EPA’s draft 

Clean Data policy

95 will not ameliorate the harms of a nonattainment designation. Merely 

allowing the State to demonstrate attainment using 2011-2013 data will not undo the damage 

caused by an erroneous nonattainment designation.

In the EPA RTC, EPA simultaneously claims that it must apply the 2010 SO2 NAAQS 

retroactively in order to meet required deadlines and that because actual control requirements 

will not be determined until the State develops a SIP, the rule does not operate retroactively.

96

 

This is similar to a defense EPA initially raised against charges of retroactive rulemaking when it 

 

92 EPA, Air Quality Designations for the 2010 Sulfur Dioxide (SO2) Primary National Ambient Air Quality 

Standard, 78 Fed. Reg. 47,191 (Aug. 5, 2013).

93 EPA, Next Steps for Area Designations and Implementation of the Sulfur Dioxide National Ambient Air Quality 

Standard, at 4-5 (Feb. 6, 2013) (proposing additional time to gather the necessary data to make subsequent 

designations for areas not designated nonattainment).

94 TSRIA Comments at 16-17, Docket EPA-HQ-OAR-2012-0233-0285; MSCC Comments at 39-41, Docket EPAHQ-OAR-2012-0233-0286.

95 See EPA, Draft Guidance for 1-Hour SO2 Nonattainment Area SIP Submissions (Oct. 28, 2013).

96 EPA, RTC, at 49-50, July 2013, Docket No. EPA-HQ-OAR-2012-0233.
27

retroactively applied a fuel additive standard under the Energy Independence and Security Act 

(EISA). However, EPA abandoned this argument and relied instead upon explicit language in 

the EISA that allowed EPA to apply the new fuel additive standards to portions of the year 

before the standard was issued to obtain an “annual average” outcome “regardless of the date of 

promulgation.”97 While the EISA explicitly allowed a form of retroactive application, there is no 

such language in the CAA regarding a NAAQS designation. 

In contrast, when retroactive application of a standard is contemplated in other parts of 

the CAA, it is explicitly set forth in the statute. For example, the CAA explicitly requires 

retroactive application of a New Source Performance Standard (NSPS) to all new sources 

constructed, reconstructed, or modified after the publication date of the proposed rule rather than 

the final rule.98 In the case of the NAAQS, however, the CAA anticipates that conclusive 

designations may not be possible or appropriate before a deadline and provides the unclassifiable 

designation as a means to avoid retroactive application of the standard. The CAA requires EPA 

to designate as unclassifiable “any area that cannot be classified on the basis of available 

information as meeting or not meeting the national primary or secondary ambient air quality

standard for the pollutant.”99 

EPA has used the unclassifiable designation for other NAAQS designations where either 

no ambient air quality data or data of questionable quality existed. Such situations often coincide 

with a substantial change to the NAAQS which requires re-configuration of the monitoring 

network or other regulatory changes that can take multiple years to implement. In its 2012 

initial designations for the NO2 NAAQS, for example, EPA designated the entire country as 

“unclassifiable/attainment” in anticipation of the deployment of a near-roadway monitoring 

 

97 National Petrochemical & Refiners Assoc. v. EPA, 630 F.3d 145, 158-59 (D.C. Cir. 2010).

98 See 42 U.S.C. § 7411(a)(2).

99 42 U.S.C. 7407(d)(1)(a)(iii).
28

network, concluding that “EPA anticipates that sufficient data to conduct redesignations would 

be available after 2015.”100 Rather than using unreliable and unrepresentative data gathered 

before the effective date of the standard to impose an unnecessary regulatory burden on 

Yellowstone County, EPA should use a similar approach to previous rulemakings and await 

complete, representative, and more accurate SO2 monitoring results.

The New Data, along with the margin of safety in the standard itself, provide added 

assurance that the public health will not be jeopardized if EPA repeals the Yellowstone County

SO2 Designation. Yellowstone County is achieving and will continue to achieve the 2010 SO2

NAAQS. Yellowstone County should not be subject to nonattainment requirements based on 

retroactive application of the standard, which will cause serious economic harm to the entire 

State and industry stakeholders in Yellowstone County. Thus, EPA should reconsider and repeal 

the Yellowstone SO2 Designation and either (1) designate Yellowstone County as attainment 

based on the New Data, (2) accept the State’s designation of Yellowstone County as 

unclassifiable, or, (3) at a minimum, group Yellowstone County with other areas that will be 

initially designated in the future based on more complete and reliable data. 

VI. EPA Should Stay the Yellowstone County Portion of the Rule

EPA should stay the Yellowstone SO2 Designation pursuant to section 307(d)(7)(B) of 

the CAA and section 705 of the APA to avoid the unnecessary development of a nonattainment 

SIP and alleviate the attendant costs and regulatory burdens on both the State and other affected 

parties.101 

 

100 77 Fed. Reg. 9532, 9535 (Feb. 17, 2012).

101 EPA regularly issues partial stays of final rules and therefore can stay only the Yellowstone SO2 Designation, as 

opposed to the entire Rule. See e.g. 77 Fed. Reg. 45967 (Aug. 2, 2012) (partial stay of NESHAP provisions).
29

Section 307(d)(7)(B) of the CAA limits a stay of a rule’s effectiveness to a three month 

period pending reconsideration.102 The limited stay provisions recognize the tight deadlines 

imposed by the CAA and the fact that a pending petition for reconsideration does not 

circumscribe a party’s ability to simultaneously seek judicial review.103 EPA, however, has 

supplemental authority under the APA to “postpone the effective date” of a rule, pending judicial 

review, where “justice so requires . . .”104 The authority granted EPA pursuant to section 705 of 

the APA is in addition to its statutory authority under CAA § 307(d)(7)(B) and is not otherwise 

limited by the more specific provisions of the CAA.105 In this case, the demands of justice and 

fairness require EPA to stay the Yellowstone SO2 Designation until such time as EPA repeals the 

Designation or judicial review is complete.

The four-part test employed by EPA when assessing whether to grant a stay under APA § 

705 weighs (1) the likelihood of success on the merits; (2) the possibility of irreparable harm to 

the petitioner; (3) harm to other parties; and (4) the ultimate public interest.106 The D.C. Circuit 

has summarized this test as follows:

(1) Has the petitioner made a strong showing that it is likely to 

prevail on the merits of its appeal? Without such a substantial 

indication of probable success, there would be no justification for 

the court’s intrusion into the ordinary processes of administration 

and judicial review. (2) Has the petitioner shown that without such 

relief, it will be irreparably injured? . . . (3) Would the issuance of 

 

102 42 U.S.C. § 7607(d)(7)(B); NRDC v Reilly, 976 F.2d 36, 41 (D.C. Cir. 1992) (“EPA had no authority to stay the 

effectiveness of a promulgated standard except for a the single, three-month period authorized by section 

307(d)(7)(B) of the CAA”).

103 42 U.S.C. § 7607(d)(7)(B).

104 5 U.S.C. § 705.

105 Sierra Club v. Jackson, 833 F. Supp. 2d 11, 25 (D.D.C. 2012) (“Without clearer evidence of congressional intent 

that that suggested by Sierra Club, the Court is unwilling to infer a congressional policy that would deprive both an 

agency and the federal courts of their traditional authority to stay rules pending judicial review as codified in Section 

705 of the APA.”).

106 Id. at 31-32 (finding that EPA must apply the four-part injunctive relief test when weighing a stay under APA § 

705). See also 76 Fed. Reg. 28,318, 28,326 (May 17, 2011) (applying four-factor test).
30

a stay substantially harm other parties interested in the 

proceedings? . . . (4) Where lies the public interest?107

In this case, the consideration of these factors works in favor of a stay of the Yellowstone SO2

Designation. 

First, as discussed at length in this petition, the October 4, 2013, petition filed by MSCC, 

and comments on the proposed Rule submitted by the State, TSRIA and the Montana Petroleum 

Association, MSCC, PPL Montana, and others, the Yellowstone SO2 Designation is based on 

non-representative data that fail to meet EPA regulatory requirements, and the area is, in fact, 

meeting the NAAQS. In light of these deficiencies and the arbitrary nature of EPA’s decisionmaking, Petitioners are likely to prevail on the merits of an appeal. Moreover, TSRIA members, 

Yellowstone County residents and businesses, and numerous other affected parties, including the 

State, will be irreparably harmed by the costly and fruitless processes of developing a 

nonattainment SIP and seeking redesignation for an area already in attainment with the SO2

NAAQS.108 Finally, public health will not be placed in jeopardy and thus the public interest 

weighs in favor of a stay.

EPA’s issuance of the National Designations triggers deadline clocks for the State to 

undertake the complex, time-intensive, and costly process of developing a nonattainment SIP for 

the 2010 SO2 NAAQS by 2015.109 Part D of the CAA enumerates requirements specific to 

nonattainment areas that States must include in their SIPs, including requirements for (1) 

comprehensive inventories of all sources; (2) adoption of “reasonably available control 

technology”; (3) provisions assuring reasonable further progress towards attainment; and (4) 

comprehensive revisions to permitting programs for the construction and operation of new and 

 

107 Washington Metropolitan Transit Comm’n v. Holiday Tours, Inc., 559 F.2d 841, 843 (D.C. Cir. 1977) (citations 

omitted).

108 See supra Section III.

109 42 U.S.C. § 7410.
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modified sources within the nonattainment area.110 Both the State and industry stakeholders will 

be irreparably harmed by the commitment of resources to design and implement the 

nonattainment SIP. Placing this process on hold during the pendency of an agency

reconsideration process would avoid unnecessary allocation of resources by the State and 

affected parties to a process that ultimately is unnecessary. 

Finally, as set forth in Section III of this petition, public health will not be harmed by a 

stay of the Yellowstone SO2 Designation. Indeed, the New Data that form the basis of this 

petition demonstrate that Yellowstone County has achieved the 2010 SO2 NAAQS with existing 

controls—and the planned mothballing of PPL Corette, the largest SO2 emitter in the county, will 

lead to further reductions in the near future. Where the NAAQS is already being achieved, the 

complex and time-intensive process of developing a nonattainment SIP and the concomitant 

costs that will be shouldered by industry stakeholders in Yellowstone County confirm that a stay

is in the public interest. 

VII. Conclusion

Based on the foregoing air quality data, planning and control considerations, and other air 

quality-related considerations, Petitioners respectfully request that EPA reconsider and repeal the 

Yellowstone SO2 Designation. Attached to this petition as Attachments A and B are technical 

documents that provide additional information about the New Data as well as details of quality

assurance requirements and practices for the Coburn Road monitor. Petitioners also request an 

opportunity to discuss these matters with EPA and to address any questions or concerns.

 

110 Id. § 7502(c)(1)-(9).