....................

Office of the President and Vice President

Post Office Box 7440 / Window Rock, AZ / 86515 / Telephone: (928) 871-7000 / Fax: (928) 871-4025

Dr. Anita Lee (Air-3)

U.S. Environmental Protection Agency Region IX

75 Hawthorne Street

San Francisco, CA 94105 

Re: Advanced Notice of Proposed Rulemaking: Assessment of Anticipated Visibility 

Improvements at Surrounding Class I Areas and Cost Effectiveness of Best Available 

Retrofit Technology of Four Corners Power Plant and Navajo Generating Station, 74 FR 

44313; Docket No. EPA-OAR-2009-0598

Dear Dr. Lee:

The Navajo Nation takes this opportunity to comment on the above-referenced 

Advanced Notice of Proposed Rulemaking (“ANPR”). The ANPR is an initial step by the United 

States Environmental Protection Agency (“USEPA”) in a rulemaking that will determine Best 

Available Retrofit Technology (“BART”) to limit the emissions of oxides of nitrogen (“NOx”) and 

particulate matter (“PM”) from two coal-fired electric power plants located on the Navajo 

Reservation – the Navajo Generating Station (“NGS”) and the Four Corners Power Plant 

(“FCPP”) (collectively “Plants”)1. For reasons set forth more fully below, the Nation supports a 

phased approach to emissions reductions for the Plants and has concluded that combustion 

controls - low Nox burners (“LNB”) and separated over fire air technology (“SOFA”), and not

selective catalytic reduction (“SCR”), are BART for both Plants at this time.

INTRODUCTION

No entity has a greater interest in NGS and FCPP than the Navajo Nation. Accordingly, 

before addressing the specific issues raised in the ANPR, the Nation believes it is important to 

lay out in broad strokes the interests of the Nation implicated by this rulemaking. NGS and 

FCPP are located on Navajo lands pursuant to lease agreements with the Navajo Nation. The 

Plants provide hundreds of skilled jobs on the Navajo Reservation, where unemployment 

 

1

For ease of reference these Comments will use FCPP and NGS to refer to both the Plants and their operators, 

Arizona Public Service and Salt River Project, respectively.
Dr. Anita Lee

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approaches fifty percent. The Nation’s most valuable saleable natural resource is its coal 

reserves, and the Plants were located to take advantage of and provide a market for Navajo 

coal. The income these two Plants provide to the Nation, both directly and indirectly, 

contributes substantially to the Nation’s economic viability and thus, ultimately, to its 

sustainability as an independent sovereign. 

The Navajo Reservation, or Diné’tah, is the homeland of the Navajo people. It is a place 

of great scenic beauty and grand scenic vistas. The Nation’s tribal parks and innumerable 

natural and archaeological treasures draw thousands of visitors each year. The Navajo people 

care deeply about their homeland and do not lightly accede to its degradation. In developing 

these comments, the Nation has balanced the environmental impacts of the Plants, the 

potential for improved visibility offered by the emission control alternatives, and the economic 

impacts that may result from the imposition of the different control technologies. The Regional 

Haze Rule requires that USEPA weigh all of these interests as well.

CAA/REGIONAL HAZE RULE REGULATORY FRAMEWORK

The Regional Haze Rule, and Section 169A of the Clean Air Act (“CAA”) from which the 

Rule was derived, have as their goal the restoration of visibility in mandatory class I Federal 

areas (“Class I Areas”), including national parks and monuments, to pristine conditions by 

2064.2 This goal is to be accomplished in incremental steps, described in the CAA and the Rule 

as “reasonable progress.”3 The Rule establishes a series of review periods in which reasonable 

progress is measured. The current rulemaking is the first review period for NGS and FCPP for 

NOx and PM.

One of the ways in which USEPA proposes to accomplish reasonable progress is to 

reduce emissions from large stationary sources like NGS and FCPP through the requirement of 

BART. The Act establishes, and the Rule reiterates, a five factor test for determining BART for 

such sources:

[T]he State [or in this instance USEPA] shall take into consideration the costs of 

compliance, the energy and nonair quality environmental impacts of compliance, any 

existing pollution control technology in use at the source, the remaining useful life of 

 

2

42 USC § 7491(a); 40 CFR § 51.308.

3

Id. at § 7491(a)(4); 40 CFR § 51.308(d)(1).
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the source, and the degree of improvement in visibility which may reasonably be 

anticipated to result from the use of such technology.

4

USEPA has issued Guidelines for BART Determinations Under the Regional Haze Rule5

(“BART Guidelines”) to aid in construction of the Rule. The BART Guidelines, which are 

mandatory for coal-fired plants like NGS and FCPP, that generate more than 750 Mw of power, 

establish presumptive limits for emissions of NOx. The preamble to the Federal Register Notice 

publishing the BART Guidelines explains that these limits, which apply to all three units at NGS 

and units 3, 4 and 5 at FCPP, “are based on current combustion control technology.”6 The 

preamble reflects USEPA’s rationale in selecting presumptive limits based on current 

combustion controls:

Based on our analysis of emissions from power plants, we believe that applying these 

highly cost-effective controls at the large power plants covered by the guidelines would 

result in significant improvements in visibility and help to ensure reasonable progress 

toward the national visibility goal.7

The ANPR focuses primarily on two control technologies that are “current combustion 

controls,” LNB and SOFA, and on SCR, a post-combustion control technology. The ANPR fails to 

adequately explain why USEPA is considering deviating from the presumptive limits and 

presumptive BART control technologies identified in the BART Guidelines.

While the Regional Haze Rule was created to protect scenic values in federal Class I 

Areas, it offers no comparable protections against visibility impacts of emissions on the Nation’s 

lands.8 To protect these and other environmental interests, the Nation has established its own 

environmental protection agency (“NNEPA”) to monitor and regulate activities affecting the 

environment on the Reservation, and NNEPA has been instrumental in the development of 

these comments. NNEPA is still in the process of developing its regulatory programs and 

capacities, however, and has not applied for “treatment as a state” or program approval for a 

visibility program.

9

 USEPA therefore is currently the sole regulatory authority determining 

 

4

Id. at § 7491(g)(2); § 51.308(e)(1)(ii)(A).

5

40 C.F.R. Part 51, Appendix Y (“BART Guidelines”); see 42 U.S.C. § 7491(b)(1).

6

40 CFR Part 51: Regional Haze Regulations and Guidelines for Best Available Retrofit Technology (BART) 

Determinations; Final Rule (“FR Notice”), 70 FR 39104, 39134 (July 6, 2005). 

7

Id. 

8

The Nation could seek to protect its lands by petitioning USEPA to have the Navajo Nation designated as a class I 

area. 42 U.S.C. § 7474(a) and (c).

9

See 42 U.S.C. § 7601(d) (CAA “treatment as a state” provision), 40 C.F.R. §§ 49.3, 49.4(e). 
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BART for the Plants, pursuant to the CAA generally and the Tribal Authority Rule.

10

 In doing so, 

however, USEPA not only has its usual obligation to solicit comments on its proposed

regulation, but also has a trust obligation, as a federal agency, to consult with the Nation as an 

affected Indian tribe. Under these circumstances, USEPA must do more than simply receive 

and respond to the Nation’s comments; it must give substantial deference to the Nation’s views 

regarding BART for stationary sources on the Nation’s lands.

COMMENTS SOLICITED BY THE ANPR

The Nation is aware that the ANPR is less comprehensive than a proposed rule and does 

not propose the installation of any particular control technology as BART for the Plants. 

Instead, as the Nation understands the purpose of the ANPR, USEPA seeks comments on two of 

the five factors that make up the BART test so that it may be fully informed before it issues a 

proposed rule. The ANPR solicits comments on data relied upon by the Plants and reviewed, 

and in some instances modified, by USEPA on these two factors. The first factor is the cost of 

installing the various control options (Factor 1). The second factor is the degree of visibility 

improvement that can be anticipated with installation of the various emissions control options 

(Factor 5), and USEPA seeks comments on the models employed and the inputs used. In the 

ANPR, USEPA provides that comments may also be submitted on the remaining three factors of 

the BART analysis. Further, USEPA indicates that comments addressing the Agency’s 

obligations under Executive Order 13175, Consultation and Coordination with Indian Tribal 

Governments (“EO 13175”)11 are also welcome.

Because of the importance to the Nation of economic issues that may be considered 

under the BART Guidelines, and that are further implicated by EO 13175, which is one tangible 

manifestation of the federal government’s trust relationship to Indian tribes, the Nation’s

comments begin with a discussion of the potential economic harm to the Nation should USEPA 

require the installation of control technologies that exceed the requirements of the Regional 

Haze Rule and that are excessively costly.

I. AFFORDABILITY OF CONTROLS, ENERGY IMPACTS (FACTOR 2) AND EO 13175

The Nation is aware of at least three authorities for considering the economic impacts of 

any proposed emission control technology. There are two distinct provisions in the BART 

 

10 40 C.F.R. § 49.11.

11 65 FR 67249 (Nov. 6, 2000).
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Guidelines that address economic impacts. In addition, USEPA’s federal trust responsibility to 

Indian tribes must inform any action taken by USEPA that has the potential for serious 

economic harm. Both Plants have raised the specter of Plant closure should USEPA require 

controls so costly that they cannot be reasonably amortized over the remaining life of the 

Plants. One need only look to the recent shut down of the Mohave Generating Station to 

realize that this is no idle threat. The Mohave closure had significant impacts on the Nation, 

even though that plant was not located on Navajo lands. Closure of Mohave was directly 

responsible for the shutdown of the Black Mesa Mine, which mined coal owned jointly by the 

Nation and the Hopi Tribe, and resulted in the loss of jobs for tribal members and royalty 

revenue for the Nation. The loss of one or both of the Plants as a consequence of this 

rulemaking would cause the Nation far greater harm.

 The BART Guidelines anticipate the situation presented here, where requiring a 

particular control technology has the potential to affect not just the profitability, but indeed the 

continued viability, of NGS and FCPP. In Section IV(E)(3), the BART Guidelines address how 

economics are factored into the BART determination once each of the five legislatively 

mandated factors have been evaluated:

In selecting a “best” alternative, should I consider the affordability of controls?

1. Even if the control technology is cost effective, there may be cases where the 

installation of controls would affect the viability of continued plant operations.

2. There may be unusual circumstances that justify taking into consideration the 

conditions of the plant and the economic effects of requiring the use of a given 

control technology. These effects would include effects on product prices, the 

market share, and profitability of the source. Where there are such unusual 

circumstances that are judged to affect plant operations, you may take into 

consideration the conditions of the plant and the economic effects of requiring the 

use of a control technology. Where these effects are judged to have a severe impact 

on plant operations you may consider them in the selection process, but you may 

wish to provide an economic analysis that demonstrates, in sufficient detail for 

public review, the specific economic effects, parameters, and reasoning.

The Nation is not prepared to concede that SCR technology is “cost effective,” and the cost 

analyses performed by the Plants support a contrary conclusion. We await further analysis by 

USEPA of the costs of compliance. However, should USEPA conclude that SCRs are cost 

effective, the provisions of the BART Guidelines quoted above clearly allow for consideration of 

economic concerns when an emission control technology option has the potential to have 

serious deleterious economic consequences. 
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A second provision in the BART Guidelines lays out the process for performing an energy 

cost assessment as part of the analysis of the energy and non-air quality environmental impacts 

factor (Factor 2). Section IV(D)(h)(5) provides that “the energy impacts analysis may consider 

whether there are relative differences between alternatives regarding the use of locally or 

regionally available coal, and whether a given alternative would result in significant economic 

disruption or unemployment (emphasis added).” As discussed below, loss of one or both of the 

Plants would likely result in the closure of the mine that supplies its coal.

Finally, as an agency of the federal government, USEPA has a responsibility to carry out 

the trust responsibility of the United States to Indian tribes. EO 13175 requires federal agencies 

to consult with Indian tribes on federal actions with tribal implications. “Policies that have 

tribal implications,” are defined to include the promulgation of regulations “that have 

substantial direct effects on one or more Indian tribes.”

12

 USEPA is clearly required by EO 

13175 to consult with the Nation and other affected tribes on the instant rulemaking to 

determine BART for NGS and FCPP. Section 5(a) of the EO, describes the consultation 

requirement: “*e+ach agency shall have an accountable process to ensure meaningful and 

timely input by tribal officials in the development of regulatory policies that have tribal 

implications.” Section 5(d) continues: “each agency should explore and, where appropriate, 

use consensual mechanisms for developing regulations, including negotiated rulemaking.” 

USEPA’s obligation to solicit comments on any proposed action is distinct from but related to its 

trust obligation, as a federal agency, to consult with affected Indian tribes.13 It is the Nation’s 

position that USEPA, as part of this consultative process, must do more than simply listen and 

respond to the Nation’s comments. To the extent that the Nation recommends a particular 

action, in this instance, the selection of a particular control technology as BART for power 

plants located on the Nation’s lands, USEPA must give substantial weight to that

recommendation as part of its decision-making process.

USEPA must consult with the Navajo Nation and must consider the potential economic 

impacts of its actions when making its BART determination. In reliance on the authorities cited 

above, the Nation presents as part of its comments on the ANPR a discussion of its economic 

interests at stake in this rulemaking. 

 

12 EO 13175, § 1(a).

13 Id. § 9(a).
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ECONOMIC INTERESTS OF THE NAVAJO NATION

The 2005-2006 Comprehensive Economic Development Strategy of the Navajo Nation14

(“Strategy Report”), summarizes Navajo Nation economic data including budget figures, 

primary sources of revenue, major employers, and employment figures. FCPP and NGS are 

listed among the largest employers within the Nation. During the period covered by the 

Strategy Report, FCPP employed 586 people, 72% of whom were members of the Nation, with 

an annual payroll of $41 million.15 Employment at NGS included 512 permanent employees, 

69% of whom were Native American. The Plant employed approximately 300 additional 

seasonal employees, with 93% being Native American. NGS had a total annual payroll of $47 

million.16 

The Plants are linked inextricably with the coal mines that supply them and the 

economic benefits indirectly attributable to the Plants include mine employment, payroll and 

royalty revenue for the Nation. FCPP burns approximately 10 million tons of coal annually from 

the BHP Navajo Mine.17 Revenues to the Nation in the form of royalties and taxes paid by the 

Navajo Mine are approximately $45.9 million.18 The Navajo Mine is also a major employer on 

the Navajo Nation, with 357 employees, 87% of whom are Navajo tribal members. Salary and 

benefits paid by the Navajo Mine exceeded $41 million in 2004.19 The Peabody Kayenta Mine 

delivers approximately 8.3 million tons of coal to NGS.20 The Kayenta Mine employs 

approximately 400 workers, a large percentage of whom are Native American, with a payroll of 

$44.4 million.21 

In an economy where unemployment has hovered just below 50% for years,22 the 

hundreds of skilled jobs provided by the Plants and the Mines are critical to the Nation’s fiscal 

well-being. Given that the number of people employed within the Nation has remained 

 

14 Available at http://www.navajobusiness.com/pdf/CEDS/CEDS%202005%20-%2006%20Final.pdf

15 Strategy Report at 28.

16 Id.

17 Id. at 28. 

18 BHB Billiton New Mexico Coal Operations: Calendar Year 2008, available at 

www.whitehouse.gov/omb.asset.aspx?Assetld=2072.

19 Strategy Report at 29. 

20 Id. at 31.

21 Id. 

22Id. at 14.
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essentially constant at about 30,000,

23 together the permanent Plant and Mine employees 

make up about 6% percent of the total Navajo Nation workforce. In 2008, cumulative revenues 

from the Plants and the Mines that supply them totaled approximately $93.9 million, 

accounting for about 55% of the Nation’s General Funds Budget of $172 million.24 

There is one additional concern unique to NGS. NGS is owned in part by the United 

States acting through the Bureau of Reclamation (“BOR”). Energy generated by NGS and 

attributed to BOR’s ownership share is used in multiple ways to subsidize the Central Arizona 

Project (“CAP”), which delivers Colorado River water for domestic, municipal, industrial and 

agricultural uses throughout central and southern Arizona. Pursuant to the Arizona Water 

Settlements Act of 2004, P.L. 108-451, revenues generated by the sale of power exceeding that 

needed to deliver CAP water may be used to fund the costs of Indian water rights settlements 

in Arizona. The Nation is currently engaged in negotiations to settle its water rights claims in 

the Lower Colorado River Basin, and will look to these funds should it reach a settlement of 

these water rights claims in the state. Further, any settlement of the Nation’s water rights 

claims in Arizona would likely also involve delivery of CAP water, and the Nation has an interest 

in keeping energy rates for delivery of CAP water at an economical level.25 Requiring emissions 

controls more extensive, and more costly, than those required to comply with the Regional 

Haze Rule, has the potential to seriously undermine the financial stability of NGS, and threaten 

the BOR revenue stream upon which both existing and future Indian water rights settlement in 

Arizona depend.

The Strategy Report provides the following commentary on the impacts of the closure of 

the Mohave Generating Station on the Navajo Nation:

Because of EPA regulations, the Mohave Generating Station near Laughlin, Nevada, 

closed its operations. As the power plant was the sole buyer of coal from Black Mesa 

Mine, it had to close its operation on January 1, 2006. Closure of this mine will 

definitely have very adverse economic impact [sic] not only on the 160 or so people laid 

off from the mine, but also on the Navajo Nation coffers.

The Nation has already suffered the ripple effects of one USEPA rulemaking that, 

through the imposition of financially untenable emissions controls, resulted in the closure of 

 

23 Id.

24 General Funds are those generated from sources internal to the Nation, as opposed to external sources, 

principally federal and state grants.

25 The Nation’s water rights settlement in New Mexico, ratified by Congress in P.L. 111-11, includes provisions for 

the delivery of CAP water through the Navajo Gallup Water Supply Project to the Nation’s capitol in Window Rock.
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the Mohave Generating Station, and as a consequence, the closure of the Black Mesa Mine. If 

either NGS or FCPP were to close as the result of the imposition of cost-prohibitive emission 

controls, the mine supplying coal to the Plant would also close. Revenue and job losses of that 

magnitude would be cataclysmic. The ripples would grow exponentially and their impact on 

the Nation would be more akin to a tsunami. USEPA must factor the economic impacts of any 

proposed action into its BART analysis.

 

II. BART FACTORS ADDRESSED BY THE ANPR

In response to the ANPR’s request for comments, the Nation takes this opportunity to 

express its serious concerns about both the methods used by USEPA to challenge the cost 

estimates of the Plants and inputs proposed to be used by USEPA to determine the degree of 

visibility improvement associated with the emission control technologies under consideration. 

FACTUAL BACKGROUND/REGULATORY CONTEXT

The Navajo Nation acknowledges that FCPP and NGS emit significant amounts of 

pollutants that the CAA seeks to control. Plants like NGS and FCPP are the focus of BART 

proceedings precisely because they are large and aging. EPA recites that FCPP is the largest 

emitter of NOx and NGS the fourth largest in the United States. However, these rankings are 

based on gross emissions measured in tons per year. A more meaningful ranking is achieved 

when emissions are considered in the context of the size of the Plants and the energy 

produced, measured in pounds per MMBtu. Using the same database relied upon by USEPA,

26

but taking into account the size of the Plants, NGS, for example, ranks number 167 out of 1,199 

coal and natural gas plants, and drops below the top 10% of polluters. When compared to only 

coal-fired power plants, it ranks number 156 out of 414, or in the 38th percentile.27

Further, coal-fired power plants are relatively small contributors to regional haze in the 

surrounding Class I Areas. The Grand Canyon Visibility Transport Commission (“GCVTC”) 

studied the numerous sources of regional haze, including both man-made (stationary sources, 

mobile sources, area sources, dust from dirt roads and prescribed forest burns) and naturally 

occurring sources (Rayleigh scattering, smoke from wildfires, wind-blown dust and volcano 

eruptions). The Western Regional Air Partnership (“WRAP”), successor to the GCVTC, concluded 

that visibility impairment caused by PM and attributable to all stationary sources is probably 

 

26 EPA “Clean Air Markets – Data and Maps”, available at http://camddataandmaps.epa.gov/gdm/

27 These calculations were performed by NGS at the Nation’s request.
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less than 2%, and that stationary source NOx emissions probably cause between 2 and 5 

percent of the visibility impairment on the Colorado Plateau.28

Finally, it is important to note that western states, in implementing the Regional Haze 

Rule, have largely rejected SCR technology due to its cost. For example, the Colorado State 

Legislature banned the consideration of SCR technology as BART for the control of NOx

emissions, even when presumptive emission limits established in the BART Guidelines would 

not be met.29

· 

The Nation recites these facts in support of its position that the BART component of the 

CAA and Regional Haze Rule was meant to provide for a measured response to emissions from 

aging power plants. Requiring the most expensive controls is inconsistent with the law and 

regulations governing the BART process, especially when, as discussed below, the incremental 

improvement attributable to such controls has not been analyzed. Further, requiring two 

power plants over which USEPA has exclusive jurisdiction to bear a greater regulatory burden 

than similarly situated plants regulated by the states is contrary to the purposes of the Act, the 

Regional Haze Rule, and to the economic interests of the Navajo Nation. 

COST OF COMPLIANCE (Factor 1)

The cost analysis for the emission control options being considered as BART for the 

Plants is the most critical of the five factors used to determine BART. Only with accurate cost 

projections can USEPA determine the cost effectiveness of any control technology. The 

disparity between the projected costs presented by the Plants and by USEPA, with the 

assistance of the National Park Service (“NPS”), demonstrates the mischief that can be 

accomplished if the cost numbers relied upon are not substantiated to the greatest possible 

extent. The Nation is not fully satisfied with the cost analysis performed by the Plants or 

USEPA. The Nation’s concerns regarding the cost estimates submitted by the Plants stem 

 

28 See Stationary Source Nox and PM Emissions in the WRAP Region: An Initial Assessment of Emissions, Controls, 

and Air Quality Impacts, Final Report of the WRAP Market Trading Forum (October 1, 2003), available at: 

www.wrapair.org/forums/mtf/nox-pm.html.

295 CCR 1001-5, Reg. 3, Part E § IV(B) (“Electric Generating Units and Fossil Fuel Boilers do not need to consider 

post combustion controls for NOx purposes in the BART analysis and the Division may not require post 

combustion controls for NOx purposes for Electric Generating Units and Fossil Fuel Boilers (emphasis added.); See 

also, WRAP BART Status (December 12, 2009), available at: 

http://www.wrapair.org/forums/ssjf/documents/bart/2009-12_BART_Status_Document.pdf. The state of Oregon 

is taking a phased approach to PGE’s Boardman Plant, a 600 Mw facility. Initially Boardman will be required to 

install LNB and SOFA technology. In a second phase, Boardman will be required to install SCR technology in 2017. 

Id.
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primarily from the lack of transparency in the cost projections. While the Nation understands 

that the Plants’ cost projections are premised in part on proprietary information, failure to fully 

document projected costs makes it difficult for the Nation to independently assess the cost 

analyses prepared by the Plants. The concerns that Nation has with USEPA’s cost analysis are 

set forth below. The Nation urges USEPA to retain an independent industry expert to analyze 

the costs associated with the retrofit control technologies being considered as BART for NGS 

and FCPP. 

USEPA and NPS rely heavily on the EPA Air Pollution Control Cost Manual (6th Ed. 

2001)30(“Manual”) in their cost analyses, consequently, the Nation’s comments on the cost of 

compliance analysis begin with an examination of the Manual. The latest version of the Manual 

was released in 2001. As the Memorandum accompanying the release of the Manual 

acknowledges, the latest revision contains “updated pricing information to at least 1990.”31 

Section 4.2 of the Manual, setting forth a cost-estimating methodology for SCR systems is 

presented in “1998 dollars.”32 In meetings between the Nation and representatives of NGS 

and FCPP, both Plant operators expressed dismay at the reliance on such a clearly outdated 

source. The Nation shares this concern. Further, the Nation is of the opinion that the experts

used by the Plants to develop their cost estimates likely have access to information about the 

design of the Plants and costs associated with retrofitting the Plants that is unavailable to 

USEPA/NPS, and that more accurately portrays the real world costs to be incurred by the Plants 

to install emission controls. 

A second concern is that USEPA/NPS are not applying the Manual in a manner 

consistent with the BART Guidelines, which provide:

The basis for equipment cost estimates also should be documented either with data 

supplied by an equipment vendor (i.e. budget estimates or bids) or by a referenced 

source (such as the [Manual]). In order to maintain and improve consistency, cost 

estimates should be based on the [Manual], where possible. The [Manual] addresses 

most control technologies in sufficient detail for a BART analysis. The cost analysis 

should also take into account any site-specific design or other conditions identified 

above that affect the cost of a particular BART technology option.33

 

30 Formerly the OAQPS [EPA Office of Air Quality Planning and Standards] Control Cost Manual.

31 See Memorandum from Daniel Mussatti (Nov. 1, 2001) available at: http://epa.gov/ttn/catc/products.html. 

32 Manual, Section 4.2, NOx Post-Combustion at 2-40. Further, the Manual explains that the “costs and estimating 

methodology in this Manual are directed toward the ‘study’ estimate with a nominal accuracy of ± 30% percent.” 

Id. at 2-3.

33 BART Guidelines at Section IV(D)(4)(a)(5).
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Clearly, the BART Guidelines anticipate both that sources other than the Manual may be used 

to establish costs, and that factors not fully addressed in the Manual, such as site-specific 

features, may be included in a cost of compliance analysis. In fact, USEPA confirmed this 

interpretation of the Manual in the preamble to the Federal Register notice published with the 

Guidelines:

We believe that the Control Cost Manual provides a good reference tool for cost 

calculations, but if there are elements or sources that are not addressed by the Control 

Cost Manual or there are additional cost methods that could be used, we believe that 

these could serve as useful supplemental information.34

USEPA disallowed, and NPS excluded, costs that appear to fall within the purview of this 

provision of the Guidelines. 

The Nation has the following specific concerns about the revisions to the Plants’ cost 

analyses:

1) USEPA should accept the annual to capital cost ratios employed by each Plant. The 

ANPR does not offer adequate justification for USEPA’s decision to use a cost ratio 

derived from other entities in neighboring states. After meeting with 

representatives of the Plants, the Nation is satisfied that the different ratios adopted 

by NGS and FCPP reflect differences in the Plants’ business structures and should be 

retained unless USEPA provides additional support for its decision.

2) Similarly, USEPA does not offer adequate justification for the proposal to install a 

half SCR on NGS Unit 2. Without further technical review, the Nation is not 

convinced that a half SCR is a realistic option for NGS.

3) Finally, the Regional Haze Rule requires not only a determination of cost 

effectiveness, but also a consideration of incremental cost-effectiveness between 

the control technologies considered.35 Given the great differences in costs projected 

by the Plants between combustion controls and SCRs, an incremental cost analysis 

should be performed. The preamble in the Federal Register notice publishing the 

revised Regional Haze Rule and BART Guidelines make this clear:

 

34 FR Notice at 39127. 

35 BART Guidelines, Section IV(D)(4)(b) and (e).
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[T]he guidelines continue to include both average and incremental costs. We 

continue to believe that both average and incremental costs provide information 

useful for making control determinations. However, we believe that these 

techniques should not be misused. For example, a source may be faced with a 

choice between two available control devices, control A and control B, where 

control B achieves slightly greater emission reductions. The average cost (total 

annual cost/total annual emission reductions) for each may be deemed to be 

reasonable. However the incremental cost (total annual costA-B/total annual 

emission reductionsA-B) of the additional emission reductions to be achieved by 

control B may be very great. In such an instance, it may be inappropriate to 

choose control B, based on its high incremental costs, even though its average 

cost may be considered reasonable.36

The failure to include an incremental cost analysis in the ANPR may have been a result 

of the limited scope of the ANPR, and may not reflect a decision that an incremental 

analysis is not required. The Nation includes a discussion of incremental costs because 

of the importance an incremental cost effectiveness analysis is likely to have in the final 

BART determination.

VISIBILITY IMPROVEMENT (FACTOR 5)

The BART Guidelines provide that a source/state would be well served to seek approval 

from USEPA prior to engaging in modeling to determine visibility improvement.37 The Nation 

has been informed that the operators of both NGS and FCPP not only sought, but secured 

USEPA approval, for their modeling protocols. Nevertheless, in the ANPR, USEPA/NPS have 

recalculated projected visibility improvement after changing important inputs to the models. 

The Nation has concerns both about the process used by USEPA in the rulemaking to date and 

about the following changes to inputs USEPA proposes for use in the CALPUFF visibility impact 

model:

1. Ammonia Background Levels. Ammonia is a precursor to particulate ammonium 

sulfate and ammonium nitrate, particles that degrade visibility and are referred to as 

secondary PM. There is very little available data on ammonia background levels at 

 

36FR Notice at 39127.

37 “In developing your modeling protocol, you may want to consult with EPA and your regional planning 

organization (RPO). Upfront consultation will ensure that key technical issues are addressed before you conduct 

your modeling.” BART Guidelines, Section III(A)(3). 
Dr. Anita Lee

Docket No. EPA-R09-OAR-2009-0598

March 1, 2010

P a g e | 14

Four Corners Class I Areas, the exception being Mesa Verde. In conducting visibility 

improvement analyses, the Plants relied on ammonia background levels previously 

accepted by USEPA for the Four Corners region. USEPA proposes to substitute 

inputs in the CALPUFF model with inputs derived by back-calculating background 

ammonia from concentrations measured by the Interagency Monitoring of 

Protected Visual Environments (“IMPROVE”) monitoring network covering Class I 

Areas. USEPA does not adequately justify the use of this back-calculation method 

for deriving background ammonia levels. NGS proposed to install, and now has 

installed, monitors capable of recording background ammonia levels. While USEPA 

discouraged NGS from monitoring for background ammonia, the Nation supports 

the use of recorded data where possible and urges USEPA to make use of such data 

as it becomes available.

2. HCl and HF Emissions. The Plants both assumed that H2SO4 was the only contributor 

to condensable organic PM. NPS proposed that HCl and HF be added to this 

category of pollutants. USEPA took a different route, and included HCl and HF as 

modeling inputs to determine PM fine. The ANPR does not adequately justify the 

addition of these compounds as modeling inputs.

3. SO4 condensable inorganic PM (H2SO4). EPA and both the Plants relied on the H2SO4

calculation methodology provided by the Electric Power Research Institute (EPRI, 

2008). However, there is a large discrepancy in the penetration factor USEPA and 

the Plants each assumed. Both Plants argue that the penetration factor used by 

USEPA is recommended for utilities burning low-sulfur eastern bituminous coal, and 

the penetration factor the Plants relied on is appropriate for the coal burned and 

conditions existing at the Plants. In March of 2009, USEPA requested NGS to 

perform H2SO4 emissions testing. Again, the Nation encourages USEPA to use 

recorded data where available. The inputs should be reviewed and the modeling 

results revised as necessary.

CONCLUSION

The Nation is of the opinion that a phased approach to emissions controls at the Plants, 

beginning with combustion controls, is fully consistent with both the CAA and the Regional 

Haze Rule. Comments submitted to USEPA to date express considerable disagreement about 

the interpretation of the data relied upon by both the Plants and USEPA. Many questions about 

the projected degree of visibility improvement turn on the models used and the inputs chosen 
Dr. Anita Lee

Docket No. EPA-R09-OAR-2009-0598

March 1, 2010

P a g e | 15

to reach these projections. Installing LNB and SOFA as a first step in a phased approach to BART 

for the Plants would:

1) Be consistent with the presumptive BART limits established in the BART Guidelines;

2) Result in a more clearly fact driven process, by allowing all interested parties to 

review recorded, not simply modeled, results at the next review phase. 

3) Aid in the resolution of disputes over the costs to install the emission control options 

under consideration by providing the opportunity to review the actual costs incurred 

by the Plants to install LNB and SOFA, which NGS is already in the process of 

installing;

4) Provide a reasonable timeframe in which to resolve outstanding lease and right of 

way issues that affect the productive life of the Plants (Factor 4). 

The Nation faces conflicting concerns as it considers the question of what level of 

emissions controls should be determined to be BART for the Plants. The Nation reached the 

position expressed in these comments only after carefully weighing these interests. While the 

Regional Haze Rule also entails a balancing of interests, the ANPR fails to consider the 

significant economic interests it implicates. We recognize that the ANPR is but a first step in 

this rulemaking process and that USEPA will offer its view of what constitutes BART for the 

Plants when the Proposed Rule is published. However, USEPA must consider the array of 

economic impacts any proposed regulatory action may have, not only on the Navajo Nation but 

on other tribes as well, and the weighing of those interests must be clearly reflected in the 

Proposed Rule. 

The Nation appreciates the efforts that USEPA has taken thus far to comply with its trust 

obligation to consult with the Nation on matters that have the potential to affect the Nation’s 

resources, including informing the Nation in advance of the publication of the ANPR. We look 

forward to a continued dialogue as USEPA moves forward with this rulemaking process.

THE NAVAJO NATION

/s/ signed on original

Joe Shirley, Jr.

President