Vol. 81 Tuesday, 

No. 128 July 5, 2016 

Part IV 

Environmental Protection Agency 

40 CFR Part 52 

Approval, Disapproval and Promulgation of Air Quality Implementation 

Plans; Partial Approval and Partial Disapproval of Air Quality 

Implementation Plans and Federal Implementation Plan; Utah; Revisions To 

Regional Haze State Implementation Plan; Federal Implementation Plan for 

Regional Haze; Final Rule 


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43894 Federal Register / Vol. 81, No. 128 / Tuesday, July 5, 2016 / Rules and Regulations 

ENVIRONMENTAL PROTECTION 

AGENCY 

40 CFR Part 52 

[EPA–R08–OAR–2015–0463; FRL–9947–42– 

Region 8] 

Approval, Disapproval and 

Promulgation of Air Quality 

Implementation Plans; Partial Approval 

and Partial Disapproval of Air Quality 

Implementation Plans and Federal 

Implementation Plan; Utah; Revisions 

to Regional Haze State Implementation 

Plan; Federal Implementation Plan for 

Regional Haze 

AGENCY: Environmental Protection 

Agency (EPA). 

ACTION: Final rule. 

SUMMARY: The Environmental Protection 

Agency (EPA) is partially approving and 

partially disapproving a State 

Implementation Plan (SIP) revision 

submitted by the State of Utah on June 

4, 2015 to implement the regional haze 

program pursuant to section 169A of the 

Clean Air Act (CAA or Act). The State’s 

SIP revisions would establish an 

alternative to best available retrofit 

technology (BART) controls that would 

otherwise be required to control 

nitrogen oxides (NOX) at PacifiCorp’s 

Hunter and Huntington power plants. 

The June 2015 SIP revision also 

includes BART determinations for 

particulate matter with an aerodynamic 

diameter of less than 10 micrometers 

(PM10) at these power plants and 

provisions for making the NOX and 

PM10 BART emission limits federally 

enforceable. The CAA requires states to 

prevent any future and remedy any 

existing man-made impairment of 

visibility in national parks and 

wilderness areas designated as Class I 

areas. Air emissions from the four 

electric generating units (EGUs) at the 

two plants affected by this action cause 

or contribute to visibility impairment at 

nine Class I areas including Grand 

Canyon, Arches, Black Canyon, Bryce 

Canyon, Canyonlands, Capitol Reef, 

Mesa Verde and Zion National Parks 

and Flat Tops Wilderness Area. The 

EPA is finalizing the option in our 

January 14, 2016 co-proposal to partially 

approve and partially disapprove the 

June 2015 SIP revision and is 

promulgating a Federal Implementation 

Plan (FIP) to address the deficiencies 

identified in our proposed partial 

disapproval of Utah’s regional haze SIP. 

The EPA is not taking any final action 

on a related October 20, 2015 SIP 

revision. The State retains its authority 

to submit a revised state plan consistent 

with CAA and Regional Haze Rule 

(RHR) requirements. An approvable SIP 

submission will result in the 

modification or withdrawal of the FIP. 

DATES: This final rule is effective August 

4, 2016. 

ADDRESSES: EPA has established a 

docket for this action under Docket ID 

No. EPA–R08–OAR–2015–0463. All 

documents in the docket are listed on 

the www.regulations.gov Web site. 

Publicly available docket materials are 

available either electronically through 

www.regulations.gov, or in hard copy at 

the Air Program, Environmental 

Protection Agency (EPA), Region 8, 

1595 Wynkoop Street, Denver, Colorado 

80202–1129. EPA requests that if, at all 

possible, you contact the individual 

listed in the FOR FURTHER INFORMATION

CONTACT section to view the hard copy 

of the docket. You may view the hard 

copy of the docket Monday through 

Friday, 8 a.m. to 4 p.m., excluding 

federal holidays. 

FOR FURTHER INFORMATION CONTACT: Gail 

Fallon, Air Program, EPA, Region 8, 

Mailcode 8P–AR, 1595 Wynkoop Street, 

Denver, Colorado, 80202–1129, (303) 

312–6281, Fallon.Gail@epa.gov. 

SUPPLEMENTARY INFORMATION: 

Table of Contents 

I. Introduction 

A. Our Co-Proposals 

1. Summary of Proposed Full Approval of 

the SIP 

2. Summary of Proposed Partial Approval 

and Partial Disapproval of the SIP and 

Proposal of a FIP 

B. Summary of the Basis for Our Final 

Decision 

1. NOX BART 

a. Regulatory Framework for BART 

Alternatives 

b. Utah’s ‘‘Greater Reasonable Progress 

Than BART’’ Metrics 

c. EPA’s Evaluation of Utah’s ‘‘Greater 

Reasonable Progress than BART’’ 

Analysis 

i. Annual Emissions Comparison of All 

Visibility-Impairing Pollutants 

ii. Improvement in Number of Days with 

Significant Visibility Impairment 

iii. 98th Percentile Modeling Impact (dv) 

iv. Annual Average Modeling Impact (dv) 

v. 90th Percentile Modeling Impact (dv) 

vi. Timing of the Emissions Reductions 

vii. Monitoring Data at the Class I Areas 

(IMPROVE Network) 

viii. Energy and Non-Air Quality Benefits 

ix. Cost 

x. EPA’s Evaluation of the State’s 

Conclusions 

d. Remaining BART Alternative Criteria 

e. Monitoring, Recordkeeping and 

Reporting for Utah’s BART Alternative 

f. Basis for Our NOX BART Determinations 

and FIP 

2. PM10 BART 

3. Enforceable Commitment SIP 

II. Summary and Analysis of Major Issues 

Raised by Commenters 

A. General Comments 

B. EPA Authority and State Discretion 

C. Reasonableness Standard 

D. Compliance With 40 CFR 51.308 

E. Overarching Comments on BART 

Alternative Demonstration 

F. Cost of Controls 

G. Comparison With Other Regional Haze 

Actions 

H. CALPUFF Modeling 

I. Consideration of Existing Controls 

J. PM10 BART 

K. Environmental Justice 

III. Final Action 

A. Final Partial Approval 

B. Final Partial Disapproval and Federal 

Implementation Plan 

C. No Action 

IV. Incorporation by Reference 

V. Statutory and Executive Order Reviews 

A. Executive Order 12866: Regulatory 

Planning and Review and Executive 

Order 13563: Improving Regulation and 

Regulatory Review 

B. Paperwork Reduction Act 

C. Regulatory Flexibility Act 

D. Unfunded Mandates Reform Act 

(UMRA) 

E. Executive Order 13132: Federalism 

F. Executive Order 13175: Consultation 

and Coordination With Indian Tribal 

Governments 

G. Executive Order 13045: Protection of 

Children From Environmental Health 

Risks and Safety Risks 

H. Executive Order 13211: Actions 

Concerning Regulations That 

Significantly Affect Energy Supply, 

Distribution, or Use 

I. National Technology Transfer and 

Advancement Act 

J. Executive Order 12898: Federal Actions 

To Address Environmental Justice in 

Minority Populations and Low-Income 

Populations 

K. Congressional Review Act 

L. Judicial Review 

I. Introduction 

The purpose of federal and state 

regional haze plans is to achieve the 

national goal, declared by Congress, of 

restoring and protecting visibility at 156 

federal Class I areas across the United 

States, most of which are national parks 

and wilderness areas with scenic vistas 

enjoyed by the American public. The 

national goal, as described in CAA 

section 169A, is the prevention of any 

future, and the remedying of any 

existing, impairment of visibility in 

mandatory Class I federal areas where 

such impairment results from manmade air pollution. States are required 

to submit SIPs that, among other things, 

ensure reasonable progress toward the 

national goal of remedying 

anthropogenic visibility impairment in 

federal Class I areas. Arizona, Colorado, 

and Utah have a wealth of such areas 

that are impacted by the Hunter and 

Huntington power plants, including 

Grand Canyon, Arches, Black Canyon, 


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1Annual average NOX emissions in tons per year 

for each of the four BART units for the period 2001– 

2003 were as follows: Hunter Unit 1 [6,380 tons/ 

yr], Hunter Unit 2 [6,092 tons/yr], Huntington Unit 

1 [5,944 tons/yr], Huntington Unit 2 [5,816 tons/yr]. 

2Refer to Tables 6 and 7 for visibility impacts. 

3 81 FR 2004 (Jan. 14, 2016). 

4For purposes of comparing the proposed BART 

Alternative to BART, Utah used most stringent NOX

control technology to represent BART, which is 

referred to as the BART Benchmark. 

5 81 FR 2004, 2012–2020 (Jan. 14, 2016). 

6Additionally, as discussed later in section I.B.3, 

at this time we not taking action on the State’s 

October 20, 2015 enforceable commitment SIP 

submittal. 

Bryce Canyon, Canyonlands, Capitol 

Reef, Mesa Verde and Zion National 

Parks and Flat Tops Wilderness Area. 

The four units at the two power plants 

that are subject to the CAA BART 

requirements are large sources of NOX,1

and the NOX emissions from these 

plants affect visibility 2 at some of the 

countries’ most beloved Class I areas 

that are visited by millions of 

Americans. The CAA requires that such 

sources install and operate controls to 

limit visibility impairing pollutants; in 

this instance there are very costeffective controls available for these 

units, which will operate for many years 

into the future. 

We proposed action on Utah’s June 4, 

2015 and October 20, 2015 regional haze 

SIP submittals addressing NOX and 

PM10 BART requirements on January 14, 

2016.3 The EPA conducted a public 

hearing for our proposed action in Salt 

Lake City, Utah on January 26, 2016. 

Our public comment period closed on 

March 14, 2016. 

In this action, we are partially 

approving and partially disapproving 

the SIP submittal submitted by Utah on 

June 4, 2015, and taking no action on 

the State’s October 20, 2015 SIP 

submittal. These submittals include 

actions intended to satisfy the State’s 

obligations for the regional haze 

program’s first planning period, 

including the obligation to submit a SIP 

containing emission limitations 

representing BART for NOX and PM for 

each of the four subject-to-BART 

sources of visibility-impairing 

emissions. We are also promulgating a 

FIP to address the deficiencies we have 

identified in the portions of the SIP 

submittal that we are disapproving. 

Utah’s SIP submittal was to address 

the BART requirements for NOX in part 

through reliance on a BART alternative 

program under 40 CFR 51.308(e)(2), 

which allows a state to implement such 

a BART alternative when the clear 

weight of the evidence demonstrates 

that it achieves greater reasonable 

progress than BART.4 Specifically, 

rather than installing and operating 

BART controls for its four subject-toBART electric generating units (EGUs), 

Utah’s SIP submittal relied on an 

alternative program, which included the 

following: (1) The installation of 

upgraded combustion controls between 

2006 and 2014 at the four BART units 

plus an additional EGU at PacifiCorp’s 

Hunter plant; and (2) the shutdown of 

the Carbon plant, a non-BART source, to 

meet the BART requirements for 

emissions of NOX. To meet its PM BART 

requirements, Utah’s SIP submittal 

included the most stringent control 

technology at each of the four subjectto-BART EGUs. We provided a detailed 

explanation of the contents of Utah’s 

June and October 2015 submittals along 

with an overview of earlier Utah 

regional haze submittals and EPA’s 

actions on these earlier submittals in 

sections IV and III.E, respectively, of our 

proposed rule.5

EPA takes very seriously a decision to 

disapprove any state plan. Our intention 

is to approve a state’s exercise of 

discretion if it can be supported. 

However, to approve a state plan EPA 

must be able to find that the plan is 

consistent with the requirements of the 

CAA and EPA’s regulations. Although 

these are largely fact-based decisions, 

we focus strongly on consistently 

applying the regional haze requirements 

across this national program. After 

carefully considering the comments on 

our proposal, we determined that there 

is only one permissible outcome. 

Therefore, for the reasons described in 

our proposal and in this action, we find 

that the State’s NOX BART Alternative 

for the power plants is not consistent 

with the applicable statutory and 

regulatory requirements. As a result, 

EPA has determined that final 

disapproval is the only path that is 

consistent with the Act. 

Although we are promulgating a 

federal plan, the State retains its 

authority to submit a revised state plan 

consistent with CAA and Regional Haze 

Rule requirements. If we determine that 

the SIP revision is approvable, 

regardless of whether or not its terms 

match those of our final FIP, we would 

propose to approve such a SIP revision. 

An approvable SIP submission will 

result in the modification or withdrawal 

of the FIP.6

A. Our Co-Proposals 

When we reviewed the Utah regional 

haze SIP, we noted that some of the 

metrics the State included in its weightof-evidence analysis presented to 

support the NOX BART Alternative 

appear to support a conclusion that the 

BART Alternative achieves greater 

reasonable progress than BART (i.e., 

selective catalytic reduction (SCR) 

technology at the four BART units at 

Hunter and Huntington). However, we 

also noted that several other metrics in 

the State’s analyses did not appear to 

support a conclusion that the BART 

Alternative achieves greater reasonable 

progress. The collection of information 

before EPA at the time of proposal 

presented a close call for us to decide 

whether to approve or disapprove the 

State’s BART Alternative. Therefore, to 

allow all interested parties an 

opportunity to comment on either 

approach, we proposed and solicited 

comment on two possible conclusions 

and courses of action: (1) The State’s 

submittal for NOX BART meets the test 

under 40 CFR 51.308(e)(2)(i)(E) and we 

approve the BART Alternative; or (2) the 

State’s submittal falls short of meeting 

this test and we disapprove the BART 

Alternative and promulgate a FIP for 

NOX BART. We requested comment on 

all aspects of each proposal. 

1. Summary of Proposed Full Approval 

of the SIP 

In one option of our co-proposal, we 

proposed to approve the following 

aspects of the State’s June 4, 2015 SIP 

submittal: 

• NOX BART Alternative, including: 

NOX emission reductions from Hunter 

Units 1, 2, and 3; Huntington Units 1 

and 2; and Carbon Units 1 and 2; and 

sulfur dioxide (SO2) and PM10 emission 

reductions from Carbon Units 1 and 2. 

• BART determinations and emission 

limits for PM10 at Hunter Units 1 and 2 

and Huntington Units 1 and 2. 

• Monitoring, recordkeeping, and 

reporting requirements for units subject 

to the BART Alternative and the PM10

emission limits. 

We also proposed to approve these 

elements of the State’s October 20, 2015 

SIP submittal: 

• Enforceable commitments to revise 

SIP Section XX.D.3.c and State rule 

R307–150 by March 2018 to clarify 

emission inventory requirements for 

tracking compliance with the SO2

milestone and properly accounting for 

the SO2 emission reductions due to the 

closure of the Carbon plant. 

2. Summary of Proposed Partial 

Approval and Partial Disapproval of the 

SIP and Proposal of a FIP 

In the other option of our co-proposal, 

we proposed to approve these elements 

of the State’s June 4, 2015 SIP submittal: 

• BART determinations and emission 

limits for PM10 at Hunter Units 1 and 2 

and Huntington Units 1 and 2. 


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7 81 FR 2004, 2007, Jan. 14, 2016. 

8 Id. 

9 40 CFR 51.308(e)(2)(i)(E). 

10 71 FR 60622 (‘‘In showing that an alternative 

program is better than BART and when there is 

confidence that the difference in visibility impacts 

between BART and the alternative scenarios are 

expected to be large enough, a weight of evidence 

comparison may be warranted in making the 

comparison.’’ (emphasis added)). 

11This section of the State’s SIP submittal 

presents the BART Alternative rule regulatory 

requirements, including EPA’s description that the 

clear weight of evidence standard uses information 

to inform a decision while recognizing the relative 

strengths and weaknesses of that information. The 

Utah SIP Section XX that was submitted to EPA, 

was adopted by the Air Quality Board on June 3, 

2015, and included the proposed provisions to 

address the NOX BART requirements. Footnote 4 in 

that Section of the SIP referenced the State’s greater 

reasonable progress demonstration. The document 

referenced in the footnote was titled ‘‘Staff Review 

2008 PM BART Determination and Recommended 

Alternative to BART for NOX, Utah Division of Air 

Quality, May 13, 2015’’ (‘‘Utah Staff Review 

Report’’ at 11). 

12 71 FR 60612, 60622 (Oct. 13, 2006). As we 

explained in adding to our final RHR the ‘‘clear 

weight of the evidence’’ standard, ‘‘ ‘[w]eight of 

evidence’ demonstrations attempt to make use of all 

available information and data which can inform a 

decision while recognizing the relative strengths 

and weaknesses of that information in arriving at 

the soundest decision possible. Factors which can 

be used in a weight of evidence determination in 

this context may include, but not be limited to, 

future projected emissions levels under the program 

as compared to under BART, future projected 

visibility conditions under the two scenarios, the 

geographic distribution of sources likely to reduce 

or increase emissions under the program as 

compared to BART sources, monitoring data and 

emissions inventories, and sensitivity analyses of 

any models used. This array of information and 

other relevant data may be of sufficient quality to 

inform the comparison of visibility impacts 

between BART and the alternative program. In 

showing that an alternative program is better than 

BART and when there is confidence that the 

difference in visibility impacts between BART and 

the alternative scenarios are expected to be large 

enough, a weight of evidence comparison may be 

warranted in making the comparison. The EPA will 

carefully consider the evidence before us in 

evaluating any [state implementation plans] 

submitted by States employing such an approach.’’ 

Id. 

• Monitoring, recordkeeping, and 

reporting requirements for units subject 

to the PM10 emission limits. 

We proposed to disapprove these 

aspects of the State’s June 4, 2015 SIP 

submittal: 

• NOX BART Alternative, including 

NOX emission reductions from Hunter 

Units 1, 2, and 3; Huntington Units 1 

and 2; and Carbon Units 1 and 2; and 

SO2 and PM10 emission reductions from 

Carbon Units 1 and 2. 

We proposed to disapprove the State’s 

October 20, 2015 SIP submittal. 

We proposed promulgation of a FIP to 

address the deficiencies in the Utah 

regional haze SIPs that were identified 

in the proposed action. The proposed 

FIP included the following elements: 

• NOX BART determinations and 

emission limits for Hunter Units 1 and 

2 and Huntington Units 1 and 2. 

• Monitoring, recordkeeping, and 

reporting requirements for NOX at 

Hunter Units 1 and 2, and Huntington 

Units 1 and 2. 

B. Summary of the Basis for Our Final 

Decision 

Based upon comments we received on 

our proposed action and our evaluation 

of both the State’s submittals and those 

comments, in this final action we are 

partially approving and partially 

disapproving Utah’s regional haze SIP 

submitted on June 4, 2015, and we are 

taking no action on Utah’s regional haze 

SIP submitted on October 20, 2015. We 

are promulgating a FIP to address the 

deficiencies we have identified in the 

portions of the SIP that we are 

disapproving. Later we present a 

summary of the major points of our final 

decision regarding the Utah regional 

haze SIP submittal that we are acting on 

today in which we summarize which 

parts of the Utah regional haze SIP 

submittal we are approving and 

disapproving and which parts are cured 

by our FIP. 

1. NOX BART 

As discussed in depth elsewhere in 

this document and in our separate 

Response to Comment (RTC) document, 

we considered the record before us and 

comments on both of our co-proposals, 

and have determined that the evidence 

does not clearly demonstrate that Utah’s 

BART Alternative makes greater 

reasonable progress than BART; that is, 

we have determined that the State’s 

Alternative is not clearly better than 

BART. Therefore, we are disapproving 

the BART Alternative contained in 

Utah’s June 4, 2015 submittal and 

promulgating a FIP to satisfy the 

regional haze program’s NOX BART 

requirements. 

In our co-proposal, to ensure our final 

decision was based on the best and most 

currently available data and 

information, we asked if interested 

parties had additional information in a 

number of areas, including: (1) Analysis 

related to the modeled visibility benefits 

of the BART Alternative compared to 

BART; and (2) other BART alternatives 

or BART control technology options 

related to what we proposed and that 

could be finalized as our FIP. We also 

asked if interested parties had 

additional information or comments on 

the proposed timeline of compliance.7

We explained that any supplemental 

information we received could lead us 

to adopt final SIP and/or FIP regulations 

that differ somewhat from the coproposals presented in our proposed 

rule regarding the BART Alternative, 

BART control technology option or 

emission limits, or impact other 

proposed regulatory provisions.8 We did 

not receive any modeling analysis 

related to the benefits of the BART 

Alternative compared to BART or any 

suggestions for consideration of other 

BART alternatives or BART control 

technology options. However, we did 

receive extensive comments on our two 

possible evaluations of Utah’s BART 

Alternative. As a result of these 

comments, we have revised some of the 

aspects of our evaluations of the State’s 

BART Alternative metrics. Based on the 

revisions to our evaluations of the 

State’s metrics, we have reassessed our 

co-proposed actions on the State’s 

BART Alternative and determined that 

it does not demonstrate greater 

reasonable progress than BART. We 

provide our reassessment of the State’s 

weight-of-evidence metrics in this 

section, and provide additional detail in 

our RTC document. 

a. Regulatory Framework for BART 

Alternatives 

To demonstrate that a BART 

alternative measure achieves greater 

reasonable progress than the BART 

requirements, EPA evaluates a SIP 

submittal to determine whether it 

demonstrates that the alternative will 

achieve greater reasonable progress 

toward natural visibility conditions than 

BART under 40 CFR 51.308(e)(3) or 

otherwise based on the clear weight of 

evidence.9 The BART Alternative rule 

requires that the alternative program 

must ‘‘clearly’’ be better than BART, 

which we have explained is ‘‘when 

there is confidence that the difference in 

visibility impacts between BART and 

the alternative scenarios are expected to 

be large enough’’ 10 to ensure that that 

the alternative is, in fact, better. 

Therefore, as part of our evaluation of 

Utah’s SIP we evaluated whether the 

differences in visibility impacts between 

BART and the State’s BART Alternative 

are ‘‘large enough’’ to satisfy the clear 

weight-of-evidence requirement. The 

State of Utah opted to develop its SIP 

under the clear weight-of-evidence 

standard, and provided its analysis in 

the ‘‘Greater Reasonable Progress than 

BART’’ section of the SIP submittal.11

As explained in our BART Alternative 

rule, the clear weight-of-evidence test 

follows these steps: 12

(1) Use information and data that can 

inform the decision. Collect information 

that can be used to assess whether the 

proposed alternative measure will 

achieve greater reasonable progress than 

BART. The information is used to 


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13We also referred to the BART Guidelines as 

authority in our proposal. 

14The BART Guidelines are mandatory in this 

action regarding both the State’s determinations of 

the BART Benchmark pursuant to 40 CFR 

51.308(e)(2)(i)(C) and EPA’s BART determinations 

in the FIP pursuant to 40 CFR 51.308(e)(1)(ii)(B). 

15 71 FR 60612, October 13, 2006. 

16Utah Staff Review Report at 12. 

17 Id. at 27 and Utah’s SIP, Section XX, Regional 

Haze (June 3, 2015) (‘‘2015 SIP’’). 

18Utah Staff Review Report at pp. 13–29. 

19As discussed in this section, Utah did not 

assign a weight to each metric. 

20 71 FR 60612, 60622. 

21See Utah Staff Review Report at p. 27 (listing 

factors the State suggested to support the BART 

Alternative in the ‘‘Summary of Weight of 

Evidence’’ section). 

22As discussed elsewhere, EPA disagrees with 

the State’s evaluation of the 98th percentile metric. 

23 40 CFR 51.308(e)(2)(i)(E). 

24Utah Staff Review Report at 11 (the BART 

alternative regulatory provisions and EPA’s 

description of the weight-of-evidence standard, 

including that a demonstration recognize the 

strengths and weaknesses of the information in 

arriving at the soundest decision possible, citing 71 

FR 60612, 60622). 

evaluate whether the visibility 

improvements at the Class I areas will 

be better under the alternative than 

under BART. Such information may 

include, but is not limited to, future 

projected emissions levels under the 

BART alternative as compared to under 

the BART benchmark; future projected 

visibility conditions under the two 

scenarios; the geographic distribution of 

sources likely to reduce or increase 

emissions under the program as 

compared to BART sources; monitoring 

data and emissions inventories; and 

sensitivity analyses of any models used. 

(2) Recognize the relative strengths 

and weaknesses of the information. 

Evaluate the information and recognize 

the relative strengths and weaknesses of 

the metrics used. This process involves 

assigning weights to each piece of 

information that indicate the degree to 

which it supports a finding that the 

alternative program will achieve greater 

visibility benefits. Such a weighing 

system might find that: (i) The 

information clearly shows the 

alternative will achieve greater 

reasonable progress than BART; (ii) the 

information supports the alternative in 

some way, but not clearly; or (iii) the 

information does not support the 

alternative. 

(3) Carefully consider all the 

information to reach a conclusion. 

Collectively consider the weights 

assigned to the individual pieces of 

information and consider the total 

weight of all the information to 

determine whether the proposed BART 

alternative will clearly provide for 

greater reasonable progress than BART 

at the impacted Class I areas. 

Additionally, in this document, we 

occasionally point to the BART 

Guidelines for authority on the analysis 

of BART alternatives (e.g., consideration 

of 98th percentile CALPUFF 

modeling).13 We acknowledge that the 

BART Guidelines are not mandatory for 

the evaluation of BART alternatives and 

the Guidelines do not directly address 

this subject.14 However, our rules at 40 

CFR 51.309 and the preamble for the 

provisions governing alternatives to 

source-specific BART determinations 15

do not provide guidance on visibility 

modeling. We rely on the BART 

Guidelines here and in other actions 

involving BART alternatives because 

they provide a reasonable and 

consistent approach regarding visibility 

modeling, as well as other aspects of a 

BART alternative, conducted as part of 

a weight-of-evidence analysis. 

b. Utah’s ‘‘Greater Reasonable Progress 

Than BART’’ Metrics 

The State collected and evaluated 

information ‘‘from a number of different 

metrics . . . to compare the two 

scenarios.’’ 16 These nine metrics 

included: (1) Annual emissions of 

visibility-impairing pollutants; (2) 

improvement in the number of days 

with significant visibility impairment 

derived from CALPUFF modeling 

results; (3) 98th percentile modeling 

impact (deciview [dv]) results derived 

from CALPUFF modeling; (4) annual 

average impact (dv) derived from 

CALPUFF modeling results; (5) 90th 

percentile impact (dv) results derived 

from CALPUFF modeling; (6) timing of 

emissions reductions; (7) results from 

IMPROVE monitoring data; (8) energy 

and non-air quality benefits; and (9) 

costs. The State considered the 

information from these metrics and 

concluded that the weight-of-evidence 

shows that its alternative program will 

provide greater reasonable progress than 

BART.17

c. EPA’s Evaluation of Utah’s ‘‘Greater 

Reasonable Progress Than BART’’ 

Analysis 

We evaluated the information for each 

of the nine metrics in the State’s SIP 

submittal,18 as well as additional 

information submitted by commenters. 

As part of this evaluation, we assessed 

the relevance and strength of each 

metric, that is, we assigned each metric 

a weight.19 After determining if, and the 

extent to which, the information the 

State relied upon was ‘‘of sufficient 

quality to inform the comparison of 

visibility impacts between BART and 

the alternative program,’’ 20 we assessed 

the metrics collectively to determine 

whether the relevant evidence, 

considered as a whole, clearly 

demonstrated that the alternative 

program achieves greater visibility 

benefits. 

Our initial review considered whether 

each of the nine metrics met the 

threshold regulatory requirement that 

information considered in a weight-ofevidence analysis be relevant to an 

assessment of visibility impacts. We 

find the State included two metrics, (1) 

energy and non-air quality impacts and 

(2) cost, that are inconsistent with the 

greater reasonable progress analysis in 

the RHR because the metrics do not 

evaluate visibility benefits at the nine 

Class I areas impacted by the State’s 

sources. Therefore, as discussed in 

detail later in sections I.B.1.c.viii and 

I.B.1.c.ix, we did not give this 

information any weight in our 

evaluation of whether the State has 

demonstrated that its BART Alternative 

achieves greater reasonable progress 

than BART. 

Additionally, the State included 

information on the aggregate annual 

emissions of all three visibilityimpairing pollutants emitted by the 

sources. However, in this particular 

instance the aggregate emissions data do 

not provide information on the likely 

visibility impacts of the State’s 

alternative program as compared to 

BART. Therefore, as discussed in detail 

later in section I.B.1.c.i, we found that 

this information was inconclusive and 

does not weigh either in favor of or 

against the BART Alternative. 

Next, we evaluated how the State 

recognized the strengths and weakness 

of the remaining six metrics. The State 

placed each metric in one of two 

categories: The information from the 

metric supported the BART Alternative, 

or it did not. The State determined that 

five of the metrics supported the BART 

Alternative 21 and one metric, the 98th 

percentile CALPUFF modeling results, 

did not support the BART Alternative.22

However, contrary to the requirement to 

weigh the evidence,23 which Utah’s SIP 

acknowledged is part of the weight-ofevidence standard,24 the SIP submittal 

did not assess the relative strengths and 

weaknesses of the metrics; that is, it did 

not explain the weight that the State 

assigned to each of the metrics it found 

supported the BART Alternative. In 

evaluating the SIP submittal, we 

assessed the relative strengths and 

weakness of each of the State’s metrics 

to determine whether it was reasonable 

for the State simply to categorize the 

metrics into the two categories (the 

metric supported the BART Alternative 

or did not support the Alternative). In 


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25The State’s Comment letter suggested the 

‘‘weight’’ for several of the metrics. 26 2015 SIP at 25, and Utah Staff Review Report 

at 27. 27EPA derived the following emissions 

reductions for the BART Alternative from the Utah 

Staff Review Report at 10, by subtracting the total 

annual emissions for the BART Alternative from the 

total annual emissions for the BART Benchmark for 

each of the visibility-pairing pollutants: SO2 8,005 

tpy, PM10 573 tpy, and NOX¥5,721 tpy (NOX is 

negative because NOX emissions increase under the 

BART Alternative). This information is also 

provided in Table 4 of our proposed rule. (81 FR 

2004, 2016.) 

28 81 FR 2004, 2029. 

29EPA unintentionally created some confusion 

with regard to this metric in our proposed rule by 

expressing this information as the total number of 

days with visibility impairment greater than 1.0 and 

0.5 dv in Tables 7 and 8, 81 FR 2004, 2017, based 

on modeling results presented in SIP TSD Ch. 6, 

Summary of Visibility Modeling. The State did not 

highlight these particular modeling results in this 

manner in its Utah Staff Review Report; rather, the 

State expressed this metric only as the average 

number of days per year over the three years 

modeled. We considered these modeling results, 

and as discussed in our RTC document, find that 

the results marginally support the Alternative. 

30See Utah Staff Review Report, pp. 19–22, and 

Ch. 6, Summary of Visibility Modeling, and 2015 

SIP at 25. 

31Utah Staff Review Report at 24. 

32 Id. at 25. 

33See id. at 27 (‘‘Summary of Weight of 

Evidence’’ section does not include 98th percentile 

modeling impact results). 

addition to information in the submittal, 

we considered suggestions on the 

amount of ‘‘weight’’ that should be 

given to each of the metrics that were 

provided by commenters on our 

proposal, including the State.25 As a 

result of our evaluation, we find that the 

State’s assessment of the metrics was 

inadequate because it did not recognize 

the relative strengths and weaknesses of 

the metrics on an individual basis. We 

also find that a proper recognition of the 

relative strengths and weaknesses, 

including the consideration that some 

metrics are more meaningful than 

others, shows that the BART Alternative 

does not achieve greater reasonable 

progress than BART. 

We evaluated each of the State’s nine 

metrics and included: (1) An assessment 

of whether we agree as a factual matter 

with the State’s conclusion; and (2) the 

weight we would give to each metric. 

Our evaluation below includes the two 

metrics that we find contain information 

that is not relevant, and the one to 

which we did not assign any weight. 

i. Annual Emissions Comparison of All 

Visibility-Impairing Pollutants 

The State’s regional haze SIP 

submittal determined that the combined 

emissions of three key visibilityimpairing pollutants will be lower 

under the BART Alternative scenario 

and that this supported the weight-ofevidence determination that the BART 

Alternative will provide greater 

reasonable progress than BART.26 27 We 

proposed to find that, since Utah’s 

BART Alternative provides greater 

emission reductions for two pollutants 

(SO2 and PM10), but that NOX emissions 

would be greater under the BART 

Alternative, it is not appropriate to 

combine all three pollutants in the 

annual emissions comparison test to 

support the BART Alternative. 

Therefore, we further proposed to find 

that the annual emissions comparison of 

all three pollutants does not show that 

the BART Alternative is better than the 

BART Benchmark.28

As a result of the comments received 

on our co-proposal, we have further 

assessed the State’s evidence for this 

metric and while we have clarified our 

assessment, we have not changed our 

overall proposed findings. Although 

emissions of two visibility-impairing 

pollutants are less under the BART 

Alternative, emissions of one of the 

pollutants would be greater. Due to 

differences in visibility impacts and 

complex interactions between 

pollutants, it is not possible to discern 

the overall visibility impacts of the 

aggregate emission reductions in this 

case without modeling; as discussed 

elsewhere, we disagree with comments 

to the contrary. Therefore, while we 

consider that aggregate emission 

reductions is a relevant concept because 

it relates to visibility impacts, in this 

particular case we continue to find that 

it is not appropriate to combine all three 

pollutants in the annual emission 

comparison test. We thus find that this 

metric is inconclusive and does not 

weigh either in favor of or against the 

BART Alternative. 

ii. Improvement in Number of Days 

With Significant Visibility Impairment 

In its regional haze SIP submittal, 

Utah provided modeling results 

comparing the number of days with 

significant visibility impairment relative 

to natural visibility under the BART 

Alternative scenario to the number of 

days under the BART Benchmark. The 

State presented this information for two 

different thresholds of visibility 

impairment: 1.0 dv of impairment 

compared to natural visibility, and 0.5 

dv of impairment. The State determined 

that the BART Alternative leads to an 

average of six fewer days per year with 

a visibility impact greater than 1.0 dv 

per year and 58 fewer days per year 

with a visibility impact greater than 0.5 

dv at the nine Class I areas.29 Utah also 

provided information in its submittal 

regarding the number of days with 

visibility improvement relative to 

baseline visibility (visibility conditions 

in 2001–2003) using a range of deciview 

thresholds (0.5 to 5.0 dv improvement 

compared to baseline visibility 

conditions).30

In EPA’s review, we considered this 

metric in our evaluation of the State’s 

weight-of-evidence analysis because the 

improvement in the number of days 

with significant visibility impairment 

relates to assessing the frequency and 

duration of visibility impacts. It is 

relevant to look at the results for the 

Class I areas individually because 

visibility impacts are location specific. 

The results for the average number of 

days with impacts over 1.0 dv show that 

seven of the nine Class I areas had the 

same result or were within one day of 

having the same result under both the 

BART Alternative and Benchmark. In 

the context of an entire year, a 

difference of one day is not particularly 

significant. Therefore, we find that the 

results from the average number of days 

with visibility impacts over the 1.0 dv 

threshold do not show the BART 

Alternative is better. We observe that 

the results for the average number of 

days with impacts over 0.5 dv show that 

the BART Alternative is better at five of 

nine Class I areas, and at four Class I 

areas the Alternative results in the same 

number of days with impacts greater 

than 0.5 dv as the Benchmark or is 

within two days of the same result 

(favoring the BART Alternative at each 

of the four where there is a two-day 

difference). Therefore, we find that the 

results from the 0.5 dv threshold show 

that the BART Alternative is marginally 

better. 

iii. 98th Percentile Modeling Impact 

(dv) 

In its regional haze SIP, the State 

determined that while the 98th 

percentile modeling impact showed 

greater reasonable progress under the 

BART Benchmark,31 several 

considerations led to the State’s 

conclusion that this metric does not give 

a complete picture of the visibility 

improvements that will be seen by 

visitors to Class I areas.32 Therefore, the 

State’s summary of the weight-ofevidence did not include the results 

from the 98th percentile modeling 

impact.33 We assessed the State’s 

evidence for this metric and proposed to 

find that on the whole, when using this 

method, the results from the BART 

Benchmark are slightly better on average 

across all years and nine Class I areas 


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34 81 FR 2004, 2030. 

35See 81 FR 2004, 2021; 40 CFR part 51, 

appendix Y, section IV.D.5; 70 FR 39104, 39129 

(July 6, 2005). See, e.g., 78 FR 79344 (Dec. 30, 2012) 

(proposed rule, FIP for Tesoro Refining and Intalco 

Refinery BART Alternatives); 79 FR 33438 (June 11, 

2014) (final rule, FIP for Tesoro Refining and 

Intalco Refinery BART Alternatives); 79 FR 56322, 

56328 (Sept. 19, 2014) (proposed approval of 

Arizona Apache BART Alternative); 80 FR 19220 

(Apr. 10, 2015) (final approval of Arizona Apache 

BART Alternative). We provide examples of use of 

the 98th modeling results for BART determinations 

in the RTC. 

36Utah Staff Review Report at 23. 

37 81 FR 2004, 2030. 

38 40 CFR part 51, appendix Y, section IV.D.5; 70 

FR 39104, 39129 (July 6, 2005). We provide 

examples of use of this information for BART 

determinations in the RTC. 

39See, e.g., 78 FR 79344, 79355 (Dec. 30, 2013) 

(proposed rule, FIP for Tesoro Refining and Intalco 

Refinery BART Alternatives in Washington), 79 FR 

56322, 56328 (Sept. 19, 2014) (proposed approval 

of Arizona Apache BART Alternative). 

40Utah Staff Review Report at 23–24, and 2015 

SIP at 25. 

41 81 FR 2004, 2030. 

42 In our North Dakota final action we explained 

that EPA addressed the appropriate interpretation 

of CALPUFF modeling results in the BART 

Guidelines within the context of subject-to-BART 

modeling and we rejected the use of the 90th 

percentile because it would be inconsistent with the 

Act. We explained that the use of the 90th 

percentile value would effectively allow visibility 

effects that are predicted to occur at the level of the 

threshold (or higher) on 36 or 37 days a year. 70 

FR 39121. 

(0.14 dv average difference). Also, this 

metric shows greater visibility 

improvement at five of nine Class I areas 

for the BART Benchmark. We proposed 

to find, consistent with the State’s 

evaluation, that this metric favors the 

BART Benchmark and does not show 

that the BART Alternative is better.34

As a result of the comments received 

on our co-proposal, we have further 

assessed the State’s evidence for this 

metric and while we have clarified our 

assessment, we have not changed our 

overall proposed finding. We 

considered this metric in our evaluation 

of the State’s weight-of-evidence 

analysis because the 98th percentile 

modeling results relate to assessing 

visibility impacts. We have considered 

all information, and consistent with the 

Agency’s approach to assessing 

visibility benefits in both BART 

determinations and other 

determinations of ‘‘greater reasonable 

progress’’ using the CALPUFF model, 

have given most weight to the visibility 

impacts based on the 98th percentile air 

quality modeling results.35

iv. Annual Average Modeling Impact 

(dv) 

The State’s regional haze SIP 

submittal stated that the average 

deciview impact metric shows the 

benefit from the BART Alternative will 

be achieved day in and day out in the 

Class I areas.36 This metric shows 

greater average visibility improvement 

at five of nine Class I areas for the BART 

Alternative. 

We assessed the State’s evidence for 

this metric and proposed to find that the 

BART Alternative is only marginally 

better than the BART Benchmark based 

on the difference in overall averages 

between the two scenarios of 0.009 dv 

and that it shows less or equal visibility 

improvement than BART at four of the 

nine Class I areas. Therefore, we 

proposed to find that the information 

from the annual average metric does not 

support a conclusion that the BART 

Alternative achieves greater reasonable 

progress than the BART Benchmark.37

As a result of the comments received 

on our co-proposal, we have further 

assessed the State’s evidence for this 

metric and we have clarified our 

assessment and finding about the State’s 

evaluation. We considered this metric in 

our evaluation of the State’s weight-ofevidence analysis because the annual 

average modeling results relate to 

assessing visibility impacts. 

Importantly, we find that the annual 

average metric is less relevant than the 

98th percentile because it does not 

provide information on visibility 

benefits on the days most impacted by 

the sources, which has been the focus of 

prior BART determinations 38 and other 

determinations of ‘‘greater reasonable 

progress’’ that relied on CALPUFF 

modeling.39 Averaging the modeling 

results over an entire year dilutes the 

emission controls’ (and BART 

Alternative emission reductions) 

potential visibility benefits and is 

inconsistent with the basis of the 

CALPUFF modeling approach used by 

the State. Additionally, the annual 

average visibility impact metric does not 

show greater visibility improvements 

than the Alternative at four of the nine 

affected Class I areas, and the average 

difference between BART and the 

Alternative across all nine of these areas 

is relatively small (0.009 dv). For these 

reasons, we find that the annual average 

impact metric in Utah’s weight-ofevidence analysis only marginally 

supports the BART Alternative. 

v. 90th Percentile Modeling Impact (dv) 

The State’s regional haze SIP 

submittal determined that the CALPUFF 

modeling results from the 90th 

percentile deciview impact show that 

the BART Alternative will provide 

greater improvement.40 We assessed the 

State’s evidence for this metric and 

proposed to find that although there was 

greater visibility improvement at seven 

of nine Class I areas for the BART 

Alternative, it was questionable if the 

BART Alternative was better based on 

the difference in the two scenarios of 

0.006 dv. We therefore proposed to find 

that it is questionable whether the 90th 

percentile supports a conclusion that 

the BART Alternative achieves greater 

reasonable progress.41

As the result of the comments 

received on our co-proposal, we have 

further assessed the State’s evidence for 

this metric and have clarified our 

assessment and finding. EPA has never 

used the CALPUFF 90th percentile 

results in other RH decisions, and we 

disapproved the use of the 90th 

percentile results for subject-to-BART 

modeling.42 Here, though, we find it is 

appropriate to consider the CALPUFF 

90th percentile results in evaluating the 

State’s weight-of-evidence analysis 

because this metric provides some 

additional information about visibility 

benefits. However, we note that the 90th 

percentile metric excludes more than a 

month’s worth of visibility data, which 

significantly dilutes the overall 

visibility results achieved from potential 

control options, and is therefore less 

relevant than the 98th percentile. 

Furthermore, while the 98th percentile 

day reflects visibility benefits on the 

days on which the sources have the 

largest impacts, the State has not 

indicated that the 90th percentile day 

has any particular significance other 

than to provide an additional metric to 

consider. We also acknowledge that the 

difference between BART and the BART 

Alternative using the 90th percentile is 

relatively small (0.006 dv). 

Additionally, we disagree with 

commenters that suggested the 90th 

percentile metric is similar to the 20% 

worst day metric; the 90th percentile 

relates to a single value, the 110th 

highest impact day across three years for 

the scenario considered (i.e., BART 

Alternative or BART Benchmark), 

whereas the 20% worst days metric 

describes visibility impacts from all 

sources on the average of the 20% worst 

visibility days. Therefore, while we 

considered the results from the 90th 

percentile to evaluate the State’s weightof-evidence analysis, we placed a very 

small amount of weight on this metric, 

and therefore find that this metric only 

marginally supports the BART 

Alternative. 

vi. Timing of the Emissions Reductions 

The State’s regional haze SIP 

submittal included statements in the 

greater reasonable progress than BART 

analysis that the NOX reductions from 

Huntington Units 1 and 2 and Hunter 


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43Utah Staff Review Report at 11, 27 (‘‘The NOX

reductions at Huntington 1 and 2 and Hunter 2 and 

3 occurred between 2006 and 2011, earlier than was 

required by the rule, providing an early and ongoing visibility improvement’’ and offering in 

footnote 14 that ‘‘[the] U.S. Circuit Court of Appeals 

for the 10th Circuit explicitly acknowledged that 

the consideration of early reductions was proper as 

part of a qualitative or clear weight of evidence 

approach to determining greater reasonable 

progress.’’ (citing WildEarth Guardians v. EPA, 770 

F.3d 919, 938 (10th Cir. 2014)). EPA agrees that it 

is appropriate to consider the timing of emission 

reductions for the Utah BART Alternative. 

44 81 FR 2004, 2030. 

45Utah Staff Review Report at 11. 

46 Id. at 27. 

47 Id. at 27. 

48 Id. at 12–19. 

49Canyonlands was the most impacted Class I 

area in the State’s BART Alternative modeling that 

assessed the visibility impacts from all three power 

plants (i.e., Hunter, Huntington, and Carbon), as 

well as most impacted in EPA’s modeling assessing 

the visibility impacts for the BART Benchmark for 

Hunter and Huntington. 

50See spreadsheet entitled, EPA Analysis of 2013 

and 2014 IMPROVE Monitoring Data for 

Canyonlands, in the docket. More detailed 

information regarding this analysis is available in 

section II.E of this document and in our RTC 

document. 

51Utah Staff Review Report at 27. 

52 40 CFR 51.308(d)(1), (e)(2)(i)(E). 

Units 2 and 3 occurred earlier than was 

required by the rule, providing 

corresponding early and ongoing 

visibility improvement under the 

Alternative as compared to the BART 

Benchmark, citing to WildEarth 

Guardians v. EPA. 770 F.3d 919, 938 

(10th Cir. 2014).43

The State further asserted that the 

timing of emission reductions provided 

support for the weight-of-evidence 

determination that the BART 

Alternative will provide greater 

reasonable progress than BART. We 

assessed the State’s evidence for this 

metric and recognized that the 

reductions from the BART Alternative 

would occur before the BART 

Benchmark because the controls at the 

Hunter and Huntington facilities have 

been achieving significant NOX

reductions since the time of their 

installation between 2006 and 2014.44

As a result of the comments received 

on our co-proposal, we have further 

assessed the State’s evidence for this 

metric. We considered the State’s early 

emission reduction statement in our 

evaluation of the State’s weight-ofevidence analysis because the 

reductions relate to assessing visibility 

impacts. We note that the State’s 

weight-of-evidence analysis presents 

and considers only the early timing of 

emission reductions from the Hunter 

and Huntington units at which controls 

were installed before 2014.45

We find that the timing of emissions 

reductions metric, which considers the 

early reductions from Hunter Units 2 

and 3 and Huntington Units 1 and 2, 

supports a finding that the BART 

Alternative is better than BART. 

vii. Monitoring Data at the Class I Areas 

(IMPROVE Network) 

The State’s regional haze SIP 

submittal determined that the BART 

Alternative provides greater reductions 

of SO2 46 and that SO2 is the most 

significant anthropogenic pollutant 

affecting Class I Areas that impacts 

visibility year-round, including 

throughout the high visitation seasons at 

the National Parks in spring, summer, 

and fall.47 The State thus concluded, 

working from assumptions regarding 

sulfate and nitrate formation based on 

historical trend data,48 that the BART 

Alternative will provide greater 

reasonable progress than BART. 

We assessed the State’s evidence for 

this metric and proposed to concur with 

one of the State’s findings. We proposed 

to find that visibility benefits associated 

with NOX reductions are much more 

likely to occur in the winter months 

because this is when aerosol 

thermodynamics favors nitrate 

formation, while SO2 emissions 

reductions should provide visibility 

benefits in all seasons. We also 

proposed to find that, as concluded by 

the Grand Canyon Visibility Transport 

Commission (GCVTC), and supported 

by the IMPROVE monitoring data 

presented by Utah, anthropogenic 

visibility impairment on the Colorado 

Plateau is dominated by sulfates. 

Therefore, we proposed to concur with 

Utah’s statement that sulfate is the 

largest contributor to visibility 

impairment at the affected Class I areas. 

We proposed to disagree with the 

State’s findings related to park 

visitation. While we explained that the 

BART Guidelines do mention visitation 

as something that can inform a control 

decision, EPA proposed to place little 

weight on the State’s correlation of 

emissions reductions and park visitation 

because nothing in the CAA suggests 

that visitors during busy time periods 

are entitled to experience better 

visibility than visitors during off-peak 

periods. 

As the result of the comments 

received on our co-proposal, we have 

further assessed the State’s evidence for 

this metric and while we have clarified 

our assessment, our overall findings 

remain the same. We considered this 

metric in our evaluation of the State’s 

weight-of-evidence analysis because the 

monitoring data relate to assessing 

visibility impacts. We conducted an 

analysis of 2013 and 2014 IMPROVE 

monitoring data for Canyonlands, the 

most impacted Class I area,49

considering seasonal averages and the 

20% best and worst days.50 Our analysis 

confirms that sulfate is a large 

contributor to light extinction year 

round and that nitrate contributions are 

highest in the winter season. 

Nonetheless, overall nitrate extinction at 

the affected areas is significant, 

particularly on the 20% worst days. We 

have taken the strength of the modeling 

results for winter months into 

consideration; however, contrary to the 

State’s and other’s suggestions that 

visibility improvements during seasons 

of peak Class I area visitation should 

carry more weight, we evaluate the 

visibility impacts for an entire year, 

regardless of the season. Therefore, we 

decided to place little weight on this 

metric and find that the monitoring data 

analysis metric in Utah’s weight-ofevidence analysis only marginally 

shows the BART Alternative is better 

than the BART Benchmark. 

viii. Energy and Non-Air Quality 

Benefits 

The State’s regional haze SIP 

submittal indicated in its weight-ofevidence assessment that the BART 

Alternative would avoid the energy 

penalty associated with operating the 

SCR units, i.e., the controls assumed 

under the BART Benchmark. The State 

also cited non-air quality benefits of its 

Alternative, including lower fly ash 

production and reduced water usage 

associated with the shutdown of 

Carbon. However, the State’s ‘‘Summary 

of the Weight of Evidence,’’ which 

presented a summary and short 

evaluation of each of the metrics, did 

not reference this assessment.51

We assessed the State’s evidence for 

this metric and proposed to find that 

because the benefits do not have direct 

bearing on whether the BART 

Alternative achieves greater reasonable 

progress, it is not material to our action 

whether we agree or disagree with 

Utah’s assessment that the Alternative 

would reduce energy and non-air 

quality impacts relative to BART. 

As a result of the comments received 

on our co-proposal, we have further 

assessed the State’s evidence for this 

metric; however, we have decided not to 

alter our proposed finding. The purpose 

of a weight-of-evidence analysis is to 

determine whether a BART Alternative 

would achieve greater reasonable 

progress, which is measured in terms of 

visibility improvement.52 Thus, only 

metrics that are indicative of 

improvements in visibility are relevant 

in a weight-of-evidence analysis. Energy 


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53Utah Staff Review Report at 27. 

54 40 CFR 51.308(d)(1), (e)(2)(i)(E). 

55We also note that, consistent with our 

statements in the BART Guidelines, the capital cost 

of controls would not be a relevant consideration 

because it does not take into account the degree of 

visibility improvement associated with those 

controls. 40 CFR part 51, appendix Y, section 

IV.D.4.g. Therefore, even if we did consider cost as 

relevant in a weight-of-evidence analysis, which we 

do not, the capital cost of controls would not be the 

appropriate metric. 

56See, e.g., 78 FR 79344 (Dec. 30, 2012) (proposed 

rule, FIP for Tesoro Refining and Intalco Refinery 

BART Alternatives); 79 FR 33438 (June 11, 2014) 

(final rule, FIP for Tesoro Refining and Intalco 

Refinery BART Alternatives); 79 FR 56322, 56328 

(Sept. 19, 2014) (proposed approval of Arizona 

Apache BART Alternative); 80 FR 19220 (Apr. 10, 

2015) (final approval of Arizona Apache BART 

Alternative). 

and non-air quality impacts do not 

provide relevant information on the 

relative visibility benefit of a BART 

Alternative as compared to BART. We, 

therefore, did not assign this metric any 

weight in our evaluation of the State’s 

weight-of-evidence conclusion. 

ix. Cost 

The State’s regional haze SIP 

indicated in its weight-of-evidence 

assessment that, although the State had 

not officially determined the cost of 

BART, it is clear that the BART 

Alternative would have significant 

capital cost savings to PacifiCorp and its 

customers. The submittal noted that the 

Carbon Plant has already been closed 

and the cost to ratepayers of replacing 

the power generated by that facility 

have already occurred. However, the 

State’s ‘‘Summary of the Weight of 

Evidence,’’ which presented a summary 

and short evaluation of each of the 

metrics, did not reference the cost 

comparison.53

We assessed the State’s evidence for 

this metric and proposed to find that 

because the described cost difference 

does not have a direct bearing on 

whether the BART Alternative achieves 

greater reasonable progress, it is not 

material to our action whether we agree 

or disagree with Utah’s conclusion that 

the BART Alternative would have a 

lower cost impact to PacifiCorp than the 

BART Benchmark (i.e., costs provided 

by PacifiCorp in its BART analyses of 

August 5, 2014, SIP TSD Chapter 2). 

As a result of the comments received 

on our co-proposal, we have further 

assessed the State’s evidence for this 

metric; however, we have decided not to 

alter our proposed finding. The purpose 

of a weight-of-evidence analysis is to 

determine whether a BART Alternative 

would achieve greater reasonable 

progress, which is measured in terms of 

visibility improvement.54 The difference 

in the capital costs between BART and 

the BART Alternative does not provide 

information relevant to the scenarios’ 

relative visibility benefits.55 We 

therefore did not assign this metric any 

weight in our evaluation of the State’s 

weight-of-evidence conclusion. 

x. EPA’s Evaluation of the State’s 

Conclusions 

The State’s regional haze SIP 

submittal suggested that eight of the 

nine metrics considered by Utah 

support the BART Alternative, finding 

that one metric, the 98th percentile 

CALPUFF modeling metric did not 

support its BART Alternative. As 

explained earlier in this section, 

evidence in the SIP and from 

commenters demonstrates that four of 

these metrics have documented 

weaknesses and only marginally 

support the BART Alternative: 

Improvement in the number of days 

with significant visibility impairment 

predicted by modeling (analyzed using 

different thresholds); the annual average 

visibility impacts predicted by 

modeling; monitoring data trends 

collected at the Class I areas; and the 

90th percentile impacts predicted by 

modeling. Additionally, while the 

timing of emission reductions metric 

does favor the State’s BART Alternative, 

the emission reductions at issue are 

only a portion of the overall emission 

reductions claimed under the 

Alternative. The timing of these 

emission reductions does not alter our 

conclusion that, on balance, the 

Alternative has not been shown to result 

in greater visibility benefits than would 

BART. Finally, we did not assign any 

weight to three metrics in our 

evaluation of the State’s weight-ofevidence analysis because we 

determined that the metrics for energy 

and non-air quality and cost 

considerations are not related to 

visibility and have no bearing on 

whether the BART Alternative achieves 

greater reasonable progress than the 

BART Benchmark, and that information 

from the annual emissions comparison 

of all visibility-impairing pollutants 

metric was inconclusive. 

When we weighed the State’s metrics 

(excluding the energy and non-air 

quality and cost metrics) that evaluate 

visibility collectively, considering the 

strengths and weaknesses of each metric 

and the magnitude of the differences in 

visibility benefit between BART and the 

Alternative, we find that it was not 

reasonable for the State to determine 

that the clear weight of the evidence 

favors the BART Alternative for the 

following reasons. We find that the 

State’s characterization of the 98th 

percentile modeling results, the one 

metric that did not support its BART 

Alternative, was contrary to EPA’s 

established interpretation of and 

reliance on that metric. The 98th 

percentile CALPUFF modeling metric 

takes into account peak visibility 

impacts and carries the most weight. 

The 98th percentile visibility impact is 

a key metric recommended by the BART 

Guidelines and EPA has relied on this 

metric in evaluating prior regional haze 

actions that have included BART 

alternatives.56 Furthermore, two factors 

which marginally support the BART 

Alternative (annual average modeled 

impact and 90th percentile modeled 

impact) are given little weight because 

they are considered to be less relevant 

metrics and show very small differences 

between the BART Alternative and the 

BART Benchmark, while another factor 

which marginally supports the BART 

Alternative (results from IMPROVE 

monitoring data) is also given little 

weight because of the need to consider 

visibility impacts during all times of the 

year, not just during peak visitation 

periods. Another factor which 

marginally supports the BART 

Alternative (improvement in number of 

days with significant visibility 

impairment) is given little weight 

because even though the BART 

Alternative is favored using a 0.5 dv 

threshold, the 1.0 dv threshold does not 

show that the BART Alternative is 

better. In addition, although a portion of 

the emission reductions under the 

Alternative were achieved prior to 2014, 

this does not diminish our fundamental 

finding that the quantity of reductions 

available under the Alternative would 

not result in greater visibility 

improvements than the emission 

reductions under BART. Therefore, the 

visibility metrics that favor the BART 

Alternative neither individually nor 

collectively clearly demonstrate that the 

BART Alternative will achieve greater 

reasonable progress at the nine Class I 

areas when weighed against visibility 

benefits predicted by the 98th percentile 

modeling results under BART. 

In summary, we have relied on the 

standards contained in the RHR and the 

authority that Congress granted us to 

review SIPs to determine whether the 

State’s SIP submittal complies with the 

minimum statutory and regulatory 

requirements. In determining SIP 

adequacy, we must exercise our 

judgment and expertise regarding 

complex technical issues, and it is 

entirely appropriate that we do so. 

Courts have recognized this necessity 

and deferred to our exercise of 


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57See, e.g., Connecticut Fund for the Env’t., Inc. 

v. EPA, 696 F.2d 169 (2d Cir. 1982); Michigan Dep’t. 

of Envtl. Quality v. Browner, 230 F.3d 181 (6th Cir. 

2000); Montana Sulphur & Chem. Co. v. EPA, 2012 

U.S. App. LEXIS 1056 (9th Cir. Jan. 19, 2012). 

58 71 FR 60612, 60621 (Oct. 13, 2006). 

59The State’s assessment of the overall weight of 

evidence states only that ‘‘[t]he weight of evidence 

shows that the alternative will provide greater 

reasonable progress than BART.’’ Utah Staff Review 

Report at 27. 

60We are disapproving SIP Sections IX.H.21, 

subsection (c), IX.H.22, subsections:.a.iii–iii., b.ii. 

and c. We are also disapproving SIP Section XX,D 

subsections: 6.a. (the provisions in the ‘‘Regional 

Haze Rule BART Requirements’’ that cover the NOX

alternative measure); 6.c. (‘‘BART for NOX, ’’ 

including footnote 4 that references the State’s 

Analysis in a separate document); 6.d. (the 

provisions in the ‘‘BART Summary’’ that cover NOX

and SO2 emissions, including the references to use 

of approval orders and permitted limits to establish 

the emission limits, the statement that ‘‘the four 

EGUs also met the presumptive emission rates for 

both NOX and SO2 established in Appendix Y 

independently of the alternative programs’’, and 

references in Table 5 to ‘‘Permitted’’ (and the NOX

and SO2 limits in that column), ‘‘Hunter 3’’, all 

provisions in the ‘‘Presumptive BART Rates’’ 

column NOX and SO2 emissions); 6.e. (the 

provisions in ‘‘Schedule for Installation of 

Controls’’ as the dates refer to emissions for sources 

that are in the proposed BART Alternative; and the 

discussion immediately following Table 6 that 

presents information about the emission limits also 

appearing in State-issued permits). Additional 

discussion appears in our RTC document. 

61 81 FR at 2021, 2025–26, 2027–28, 2032 

62As explained later, our co-proposal proposed to 

approve or conditionally approve the remainder of 

the monitoring, recordkeeping and reporting 

requirements associated with Utah’s PM10 BART 

determinations. 

63However, we note that we are proposing 

conditional approval of the following regulations in 

Section IX.H.21(e), as discussed in section I.B.2. 

discretion when reviewing SIPs.57 We 

thus review a state’s SIP submittal with 

the understanding that the state’s 

discretion in developing an alternative 

measure ‘‘is subject to the condition that 

it must be reasonably exercised and that 

its decision is supported by adequate 

documents of its analysis.’’ 58 In the 

present circumstance—as discussed in 

more detail in the proposed action and 

this final action—EPA was not able to 

find that the weight-of-evidence 

analysis satisfied the relevant regulatory 

requirements. Specifically, we find: 

(1) The State’s assessment of the 

metrics it found to support its BART 

Alternative was inadequate because it 

did not evaluate the relative strengths 

and weaknesses of the visibility metrics 

on an individual basis; 

(2) The State did not consider the 

98th percentile CALPUFF modeling 

metric, which did not support its BART 

Alternative, in a manner consistent with 

EPA’s established interpretation of and 

reliance on that metric; 

(3) The State’s assessment of the 

metric that considered aggregate annual 

emissions of visibility-impairing 

pollutants was contrary to EPA’s 

established interpretation of and 

reliance on that metric; 

(4) The State’s assessment relied on 

two metrics that are not consistent with 

the ‘‘greater reasonable progress’’ 

analysis because they are not related to 

visibility (energy and non-air quality 

and cost considerations); 

(5) The State did not satisfy the 

requirement that it assess the collective 

weight of its evidence in a reasonable 

and adequately supported manner; and 

(6) The SIP submittal lacked an 

explanation of why the information 

from all the metrics demonstrated that 

the difference in visibility impacts 

between BART and the Alternative was 

large enough to ‘‘clearly’’ demonstrate 

that the BART Alternative would 

achieve greater reasonable progress than 

BART.59

Based on this evaluation, we find that, 

on balance, the evidence does not show 

that the Alternative clearly achieves 

greater visibility benefits than BART. 

Thus, the State has not satisfied the 

regulatory requirement in 40 CFR 

51.308(e)(2) that a state’s submittal of a 

BART alternative include a 

‘‘determination . . . based on the clear 

weight of evidence that the . . . 

alternative measure achieve greater 

reasonable progress than would be 

achieved through the installation and 

operation of BART at the covered 

sources.’’ Therefore, we are 

disapproving the State’s NOX BART 

Alternative contained in its June 4, 2015 

SIP submittal, including the NOX

emission limits for Hunter Units 1, 2, 

and 3; and the NOX emission limits for 

Huntington Units 1 and 2; and the 

requirements for permanent closure of 

Carbon Units 1 and 2.60

d. Remaining BART Alternative Criteria 

The RHR establishes a number of 

additional regulatory criteria to be 

included in any demonstration that an 

alternative will provide for greater 

reasonable progress than BART. These 

criteria are set out at 40 CFR 

51.308(e)(2)(i)(A)–(D) and (e)(2)(iii)–(v). 

In both co-proposals, we proposed to 

find that Utah’s SIP submittal 

addressing the BART Alternative met 

these requirements.61 We received 

adverse and supportive comments on 

our proposed finding that the State had 

met these remaining requirements. We 

respond to these comments in our RTC 

document. 

Having carefully considered the 

comments received, we have concluded 

that the State’s SIP submittal generally 

met most of these requirements, as 

explained in our RTC document. As a 

result, our partial disapproval of the 

State’s SIP submittal is based on our 

assessment that Utah failed to 

demonstrate based on the weight of 

evidence that the BART Alternative 

would provide for greater reasonable 

progress and not on any deficiencies in 

the state’s demonstration that it had met 

the additional regulatory criteria in 40 

CFR 51.308(e)(2). 

e. Monitoring, Recordkeeping and 

Reporting for Utah’s BART Alternative 

Section IV.B.3 of Utah’s June 2015 

regional haze SIP included enforceable 

measures and monitoring, 

recordkeeping and reporting 

requirements for the Utah BART 

Alternative and the State’s PM10 BART 

determinations. In our co-proposal we 

proposed to disapprove (in other words, 

to not make federally enforceable as part 

of the SIP) the monitoring, 

recordkeeping and reporting 

requirements located in SIP Sections 

IX.H.22 associated with the BART 

Alternative. This includes SIP Section 

IX.H.22, subsections a.ii, a.iii, b.ii, and 

c.i.62

While we did not receive any 

comments on this element of Utah’s 

regional haze SIP submittal in our coproposal, the monitoring, 

recordkeeping, and reporting provisions 

in the submittal are linked directly to 

the emission limitations under the 

Alternative, which we are 

disapproving.63 Our partial disapproval 

of the State’s SIP submittal is based on 

our assessment that Utah failed to 

demonstrate based on the weight of 

evidence that the BART Alternative 

would provide for greater reasonable 

progress and not on any deficiencies in 

the State’s demonstration that it had met 

the monitoring, recordkeeping, and 

reporting requirements under the RHR. 

f. Basis for Our NOX BART 

Determinations and FIP 

Based upon comments we received on 

our proposed FIP, we revised our 

analysis of the cost of installing and 

operating NOX BART controls at the 

four subject-to-BART EGUs. In 

particular, and as discussed at length in 

our RTC document, we revised the costs 

in response to comments from 

PacifiCorp that we incorrectly redesigned the SCR reactors. Having 

carefully considered the comments 

received, we concluded it was 

unnecessary to revise our analysis of 

visibility improvement or the other 

statutory BART factors. Our proposed 

action contains a full description of the 

five step BART analysis, the five BART 

factors, and our proposed BART 

determination. Because we have revised 


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our cost analysis, we provide updated 

tables containing the results of the cost 

analyses, including the summary tables 

that also show the visibility 

improvements associated with the 

controls under consideration (which we 

did not revise). Following these tables, 

we provide our final BART 

determination. Because the Hunter and 

Huntington BART units are similar, our 

reasoning for the final BART 

determination applies to all four units. 

Table 1 shows the NOX BART control 

technologies, associated cost, emission 

reductions, and the BART emission 

limitation for each source that is subject 

to the FIP. The costs in Table 1 reflect 

EPA’s revised cost analysis. Please note 

that the cost-effectiveness values for 

SCR with low-NOX burners and 

separated overfire air (SCR + LNB/

SOFA) were computed using an 

assumed emission rate of 0.05 lb/

MMBtu on an annual basis, but for 

compliance purposes the NOX emission 

limit for each unit is 0.07 lb/MMBtu, 30- 

day rolling average. 

TABLE 1—EMISSION LIMITS, COSTS, AND COST EFFECTIVENESS FOR LNBS/SOFA WITH SCR FOR THE SOURCES

SUBJECT TO THE FIP 

Source Technology * 

NOX Emission 

limit—lb/

MMBtu 

(30-day rolling 

average) 

Total capital 

cost 

($) 

Total 

annualized 

cost 

($) 

Average costeffectiveness 

($/ton) 

Hunter Unit 1 ........................................................................ SCR + LNB/

SOFA 

0.07 $130.6M $14.8M $2,697 

Hunter Unit 2 ........................................................................ SCR + LNB/

SOFA 

0.07 128.5M 14.5M 2,774 

Huntington Unit 1 ................................................................. SCR + LNB/

SOFA 

0.07 128.3M 14.6M 2,871 

Huntington Unit 2 ................................................................. SCR + LNB/

SOFA 

0.07 130.0M 14.7M 2,928 

* The technology listed is the technology evaluated as BART, but sources can choose to use another technology or combination of technologies to meet established limits. 

Tables 2 and 3 provide summaries of 

EPA’s NOX BART analysis of all feasible 

control options for Hunter Units 1 and 

2, including the costs of compliance and 

visibility impacts. Please refer to our 

discussion in section I.B.1.f in regard to 

how we selected BART from among 

these control options. 

TABLE 2—SUMMARY OF EPA’S HUNTER UNIT 1 NOX BART IMPACTS ANALYSIS

Control option 

Annual 

emission 

rate 

(lb/MMBtu) 

Emission 

reduction 

(tpy) 

Total annual costs 

(million$) 

Average 

cost effectiveness 

($/ton) 

Incremental cost effectiveness 

($/ton) 

Visibility impacts * 

Improvement 

(dv) 

Days > 0.5 

dv 

Days > 1.0 

dv 

LNB with SOFA ............................ 0.21 3,042 $1.2M $382 ...................................................... 0.846 330 (29) 218 (22) 

LNB with SOFA and SNCR .......... 0.16 3,735 3.8M 1,016 3,796 ............................................ 1.041 322 (37) 202 (38) 

LNB with SOFA and SCR ............ 0.05 5,500 14.8M 2,697 6,255 (compared to LNB with 

SOFA and SNCR) 5,561 (compared to LNB with SOFA).

1.545 311 (48) 188 (52) 

* At the most impacted Class I area, Canyonlands National Park. The improvement in days over 0.5 and 1.0 dv provided by the control option relative to the baseline is presented in parentheses. See Table H.9. Air Quality Modeling Protocol: Utah Regional Haze Federal Implementation Plan, US EPA Region 8 (Nov. 2015); 

Docket Id. EPA–R08–OAR–2015–0463–0012. 

TABLE 3—SUMMARY OF EPA’S HUNTER UNIT 2 NOX BART IMPACTS ANALYSIS

Control option 

Annual 

emission 

rate 

(lb/MMBtu) 

Emission 

reduction 

(tpy) 

Total annual costs 

(million$) 

Average 

cost effectiveness 

($/ton) 

Incremental cost effectiveness 

($/ton) 

Visibility impacts * 

Improvement 

(dv) 

Days > 0.5 

dv 

Days > 1.0 

dv 

LNB with SOFA ............................ 0.20 2,902 $0.9M $298 ...................................................... 0.658 336 (23) 221 (19) 

LNB with SOFA and SNCR .......... 0.16 3,562 3.5M 968 3,913 ............................................ 0.822 331 (28) 218 (22) 

LNB with SOFA and SCR ............ 0.05 5,230 14.5M 2,774 6,632 (compared to LNB with 

SOFA and SNCR) 5,861 (compared to LNB with SOFA).

1.250 317 (42) 198 (42) 

* At the most impacted Class I area, Canyonlands National Park. The improvement in days over 0.5 and 1.0 dv provided by the control option relative to the baseline is presented in parentheses. See Table H.10. Air Quality Modeling Protocol: Utah Regional Haze Federal Implementation Plan, US EPA Region 8 (Nov. 2015); 

Docket Id. EPA–R08–OAR–2015–0463–0012. 

Tables 4 and 5 provide summaries of 

EPA’s NOX BART analysis of all feasible 

control options for Huntington Units 1 

and 2, including the costs of compliance 

and visibility impacts. 


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64As discussed in our proposal action, in the 

context of reasonable progress determinations, a 

comparison with another reasonable progress 

determination has been upheld by the Ninth Circuit 

Court of Appeals as a rational explanation for that 

determination. Nat’l Parks Conserv. Ass’n v. U.S. 

EPA, 788 F.3d 1134, 1148–49 (9th Cir. 2014). 

65 79 FR 5032, 5047 (Jan. 30, 2014). 

66As explained in our proposal, the BART 

Guidelines require consideration of the visibility 

improvement from the use of BART controls 

applied to the collection of emissions units that 

make up the BART source. Although this requires 

consideration of the visibility improvement from 

BART applied to the subject-to-BART source as a 

whole, states (and EPA) may also include the 

visibility benefits on a per unit basis as well in their 

evaluation of the BART factors. In this action we 

have considered both the per-unit visibility benefits 

as well as the source-wide visibility benefits. The 

source-wide visibility benefits of our selected BART 

control, SCR + LNB/SOFA, at all nine impacted 

Class I areas are presented and discussed later. 

TABLE 4—SUMMARY OF EPA’S HUNTINGTON UNIT 1 NOX BART IMPACTS ANALYSIS

Control option 

Annual 

emission 

rate 

(lb/MMBtu) 

Emission 

reduction 

(tpy) 

Total annual costs 

(million$) 

Average 

cost effectiveness 

($/ton) 

Incremental cost effectiveness 

($/ton) 

Visibility impacts * 

Improvement 

(dv) 

Days > 0.5 

dv 

Days > 1.0 

dv 

LNB with SOFA ............................ 0.22 2,440 $0.8M $332 ...................................................... 0.851 249 (28) 153 (22) 

LNB with SOFA and SNCR .......... 0.17 3,185 3.5M 1098 3,609 ............................................ 1.113 244 (33) 143 (32) 

LNB with SOFA and SCR ............ 0.05 5,092 14.6M 2,871 5,830 (compared to LNB with 

SOFA and SNCR) 5,206 (compared to LNB with SOFA).

1.881 210 (67) 117 (58) 

* At the most impacted Class I area, Canyonlands National Park. The improvement in days over 0.5 and 1.0 dv provided by the control option relative to the baseline is presented in parentheses. See Table H.11. Air Quality Modeling Protocol: Utah Regional Haze Federal Implementation Plan, US EPA Region 8 (Nov. 2015); 

Docket Id. EPA–R08–OAR–2015–0463–0012. 

TABLE 5—SUMMARY OF EPA’S HUNTINGTON UNIT 2 NOX BART IMPACTS ANALYSIS

Control option 

Annual 

emission 

rate 

(lb/MMBtu) 

Emission 

reduction 

(tpy) 

Total annual costs 

(million$) 

Average 

cost effectiveness 

($/ton) 

Incremental cost effectiveness 

($/ton) 

Visibility impacts * 

Improvement 

(dv) 

Days > 0.5 

dv 

Days > 1.0 

dv 

LNB with SOFA ............................ 0.21 2,576 $0.9M $365 ...................................................... 0.776 254 (23) 153 (22) 

LNB with SOFA and SNCR .......... 0.17 3,264 3.5M 1,075 3,730 ............................................ 1.016 244 (33) 149 (26) 

LNB with SOFA and SCR ............ 0.05 5,023 14.7M 2,928 6,368 (compared to LNB with 

SOFA and SNCR) 5,626 (compared to LNB with SOFA).

1.657 220 (57) 126 (49) 

* At the most impacted Class I area, Canyonlands National Park. The improvement in days over 0.5 and 1.0 dv provided by the control option relative to the baseline is presented in parentheses. See Table H.12. Air Quality Modeling Protocol: Utah Regional Haze Federal Implementation Plan, US EPA Region 8 (Nov. 2015); 

Docket Id. EPA–R08–OAR–2015–0463–0012. 

In our final BART determinations, we 

have taken into consideration all five of 

the statutory factors required by the 

CAA: Costs of compliance, energy and 

non-air quality environmental impacts 

of compliance, any existing pollution 

control technology in use at the source, 

remaining useful life of the source, and 

degree of improvement in visibility 

which may reasonably be anticipated to 

result from the use of such technology. 

We received some comments on our 

proposed consideration of remaining 

useful life and energy and non-air 

quality environmental impacts. 

However, we have not changed our 

evaluation from the proposal of the 

energy and non-air quality 

environmental impacts of compliance 

and the remaining useful lives of the 

sources. We find that the remaining 

useful life of the Hunter and Huntington 

units of at least twenty years is 

considerable and does not require us to 

revise our amortization period for the 

costs of controls. We also find that the 

energy and non-air quality 

environmental impacts of the various 

control options do not significantly 

favor one option over another. Please 

see the proposal action and our RTC 

document for details. 

We also received comments on our 

proposed consideration of existing 

pollution control technology in use at 

the source, in this case LNB/SOFA at all 

four BART units. For reasons explained 

later in the preamble and in our RTC 

document, we continue to use a baseline 

period for emissions (2001–2003) that 

predates the installation of LNB/SOFA 

at the four BART units. We have 

considered the existing LNB/SOFA in 

several other ways. First, we considered 

them in selecting the control options to 

analyze for BART. Second, we 

considered them in determining the 

impacts of the control options, both by 

taking the LNB/SOFA into account in 

determining the proper NOX rates for 

the post-combustion control options 

(selective non-catalytic reduction 

(SNCR) and SCR), and in computing the 

incremental cost-effectiveness values in 

the tables earlier. We also consider the 

existing LNB/SOFA in our discussion of 

incremental visibility benefits later. As 

explained later in the preamble and in 

our RTC document, this is a reasonable 

approach and consistent with other 

actions. 

We now discuss the remaining 

factors, the costs of compliance and the 

degree of visibility improvement, and 

how we are weighing them in 

determining BART. At this point in 

time, EPA and the states have made a 

number of BART determinations for 

large coal-fired EGUs. EPA is taking into 

account the BART decisions made in 

other states to help frame our 

assessment of the cost and visibility 

benefits of control options in this 

action.64 Specifically, we have 

compared the average cost-effectiveness, 

incremental cost-effectiveness, visibility 

improvement, and incremental visibility 

improvement for the selected BART 

controls, SCR + LNB/SOFA, with BART 

determinations for coal-fired EGUs 

where the EPA and states have based 

those determinations on the same or 

similar metrics. 

The most comparable determination 

is in EPA’s final action on Wyoming’s 

regional haze SIP, in which EPA 

promulgated a FIP for three units at 

Laramie River Station and determined 

NOX BART to be SCR + LNB/SOFA for 

the three units.65 On a per-unit basis, 

the visibility improvement at the most 

impacted Class I area from this control 

option ranged from 0.52 to 0.57 dv, and 

across all three units the sum of the 

improvement was 1.62 dv.66 Thus, 

applying this control option to all three 

units of Laramie River Station was 

estimated to have a visibility benefit 


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67 77 FR 18069 (Mar. 26, 2012) (proposal); 77 FR 

76871 (Dec. 31, 2012) (final). 

68Colorado Department of Health and 

Environment, Air Pollution Control Division, 

Technical Review Document, Renewal/

Modification of Operating Permit 96OPRO132, 

Public Service Company—Hayden Station, 

Colorado, at 2 (2007–2008). 

69We respond later in this action and in our RTC 

document about comments that this comparison 

should not be used because the baseline for Hayden 

included the existing controls. 

about the same as applying the same 

control option to just one of the Hunter 

and Huntington BART units (the 

visibility benefits in today’s action at 

the most impacted Class I area range 

from 1.25 dv at Hunter Unit 2 to 1.881 

dv at Huntington Unit 1). The visibility 

benefits of SCR + LNB/SOFA at Hunter 

or Huntington as a whole (2.948 dv for 

Hunter, 3.848 dv for Huntington) are 

significantly greater than at Laramie 

River Station. 

The average cost-effectiveness for SCR 

+ LNB/SOFA at Laramie River Station 

ranged from $4,375/ton to $4,461/ton, 

considerably higher than the 

corresponding values of $2,697/ton to 

$2,928/ton for the Hunter and 

Huntington BART units. The 

incremental cost-effectiveness for SCR + 

LNB/SOFA at Laramie River Station as 

compared to SNCR + LNB/SOFA ranged 

from $5,449 to $5,871/ton, which is 

generally in line with the corresponding 

values for the Hunter and Huntington 

BART units, $5,830/ton to $6,632/ton. 

Finally, the incremental visibility 

improvement for SCR + LNB/SOFA at 

the most impacted Class I area as 

compared to SNCR + LNB/SOFA for 

Laramie River Station was significant 

(0.25 dv to 0.29 dv), but is even more 

so for the Hunter and Huntington BART 

units (0.428 dv at Hunter Unit 2 to 0.748 

dv at Huntington Unit 1). Thus, the 

selection of SCR + LNB/SOFA at the 

Hunter and Huntington BART units is 

very much in line with the selection of 

SCR + LNB/SOFA at Laramie River 

Station. This is particularly true given 

that Laramie River Station impacts four 

Class I areas, while the Hunter and 

Huntington BART units impact nine 

Class I areas. 

In the same Wyoming action, our 

BART determinations for Dave Johnston 

Units 3 and 4 also provide a useful 

comparison. At Unit 3, we selected SCR 

+ LNB/OFA as BART based on an 

assumed 20-year remaining useful life. 

Under that assumption, the average 

cost-effectiveness and incremental costeffectiveness (as compared to SNCR + 

LNB/OFA) were $2,635/ton and $7,583/ 

ton, respectively. We found these costs 

reasonable in light of a 0.51 dv 

improvement and a 0.12 dv incremental 

improvement at the most impacted 

Class I area. The average costeffectiveness of SCR + LNB/SOFA at the 

Hunter and Huntington BART units, 

$2,697/ton to $2,928/ton, is comparable, 

while the incremental cost-effectiveness 

of SCR + LNB/SOFA at the Hunter and 

Huntington BART units, $5,830/ton to 

$6,830/ton, is less than at Dave Johnston 

Unit 3. On the other hand, the visibility 

benefit and incremental visibility 

benefit of SCR + LNB/SOFA at the 

Hunter and Huntington BART units is 

considerably higher than that at Dave 

Johnston Unit 3, and the Hunter and 

Huntington BART units impact nine 

Class I areas as compared to five for 

Dave Johnston Unit 3. Thus, the 

selection of SCR + LNB/SOFA for the 

Hunter and Huntington BART units is 

very much in line with our BART 

determination for Dave Johnston Unit 3 

(assuming a remaining useful life of 20 

years). 

In the Wyoming action, at the request 

of PacifiCorp we also analyzed an 

alternative compliance scenario for 

Dave Johnston Unit 3 that assumed a 

shutdown in 2027 and correspondingly 

a 9-year remaining useful life. As 

explained in the BART Guidelines, for 

BART units with a relatively short 

remaining useful life—in other words, 

less than the time period used for 

amortizing costs, which in this case was 

20 years—the shorter time period can be 

used to amortize costs instead. 

Effectively, this increases the costeffectiveness values; in the case of Dave 

Johnston Unit 3, the average and 

incremental cost-effectiveness of SCR + 

LNB/OFA increased to $3,742/ton and 

$11,781/ton, respectively. Considering 

these values against the visibility 

benefits, we found that the incremental 

cost-effectiveness of SCR + LNB/OFA in 

this instance was not reasonable. Of 

course, for the Hunter and Huntington 

BART units the incremental costeffectiveness is much lower than this 

scenario and in line with the previous 

scenario assuming a 20-year remaining 

useful life, for which we selected SCR 

+ LNB/OFA as BART. Similarly, for 

Dave Johnston Unit 4, as for the 9-year 

remaining useful life scenario for Unit 3, 

we rejected SCR + LNB/OFA due to a 

high incremental cost-effectiveness of 

$13,312. This is again consistent with 

our determination here, given the much 

lower incremental cost-effectiveness 

numbers for SCR + LNB/SOFA at the 

Hunter and Huntington BART units. 

There are other BART determinations 

in which SCR has been selected as 

BART (either alone or in conjunction 

with LNB and SOFA) based on similar 

metrics, although those determinations 

may not have explicitly discussed 

incremental cost-effectiveness and 

incremental visibility benefits on a perunit basis. First, the State of Colorado 

selected, and the EPA approved, SCR as 

NOX BART for Public Service 

Company’s Hayden Station, Units 1 and 

2.67 Hayden Units 1 and 2 were 

equipped with first generation LNB and 

over-fire air (OFA) installed in 1999 as 

the result of a consent decree to address 

other CAA requirements.68 In its BART 

determination, Colorado considered 

these existing controls as given and 

included them in the baseline 

emissions, which is consistent with our 

approach here: Colorado included the 

Hayden combustion controls in the 

baseline because they were not installed 

for a proposed BART determination but 

for other CAA purposes. In contrast, we 

do not include the combustion controls 

at Hunter and Huntington because they 

were installed pursuant to a proposed 

BART determination.69

Colorado analyzed as feasible controls 

upgraded LNB, SNCR, and SCR. Based 

on an average cost-effectiveness of 

$3,385/ton and $4,064/ton, incremental 

cost-effectiveness (as compared with 

SNCR + the existing LNB/OFA) of 

$5,326/ton and $7,331/ton, and 

visibility improvement of 1.12 dv and 

0.85 dv at the most impacted Class I 

area, respectively, Colorado selected 

SCR (added to the existing LNB/OFA) as 

BART for Units 1 and 2. The average 

cost-effectiveness of SCR + LNB/SOFA 

at the Hunter and Huntington BART 

units, $2,697/ton to $2,928/ton, 

compares favorably with the average 

cost-effectiveness of SCR at the Hayden 

units, and the incremental costeffectiveness of SCR + LNB/SOFA at the 

Hunter and Huntington BART units, 

$5,830/ton to $6,632/ton, is generally in 

line with the incremental costeffectiveness of SCR at the Hayden 

units. The visibility improvement from 

SCR + LNB/SOFA at the most impacted 

Class I area for the Hunter and 

Huntington BART units, from 1.25 dv to 

1.881 dv, compares favorably with the 

Hayden units. While Colorado appears 

to have not considered the incremental 

visibility benefits, these are also 

favorable for our selection of SCR + 

LNB/SOFA: 0.428 dv to 0.768 at the 

Hunter and Huntington units, as 

compared to 0.37 dv and 0.43 dv at 

Hayden Units 1 and 2, respectively. We 

also note that Hayden Station impacts 

eleven Class I areas, slightly more than 

Hunter and Huntington; however for six 

of those areas the impacts from Hayden 

Station are less than the impacts from 

Hunter and Huntington at the least 


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70See BART CALPUFF Class I Federal Area 

Individual Source Attribution Visibility Impairment 

Modeling Analysis for Public Service Company of 

Colorado Hayden Station Units 1 and 2, Colorado 

Department of Public Health, at 48 (Nov. 1, 2005). 71 77 FR 42834 (July 20, 2012) (proposal); 77 FR 

72512, 72514–15 (Dec. 5, 2012) (final). 

72 In response to a comment about the use of this 

baseline, EPA explained that the three Cholla units 

had installed LNB/OFA and switched to a new 

source of coal with a much higher potential for NOX

emissions. Thus, the LNB/OFA had not been 

installed pursuant to a proposed state BART 

determination; instead they appear to have been 

installed to accommodate the use of the new coal. 

This is again distinguishable from the situation for 

Hunter and Huntington. 

73As explained later and in our RTC document, 

we reject the comparisons to BART determinations 

in Montana, Florida, and Nebraska. 

impacted Class I area, Zion National 

Park.70

Another comparable determination 

can be found in EPA’s FIP for Arizona 

Public Service’s Cholla Power Plant, 

Units 2, 3, and 4, in which EPA 

determined that NOX BART was SCR for 

all three units.71 Similar to Colorado’s 

determination for Hayden, EPA 

included the existing controls, LNB and 

OFA, in the baseline for the three 

units.72 EPA estimated average costeffectiveness values for SCR (as added 

to the existing LNB/OFA) of $3,114/ton, 

$3,472/ton, and $3,395/ton; and 

incremental cost-effectiveness values (as 

compared to SNCR + LNB/OFA) of 

$3,257/ton, $3,811/ton, and $3,661/ton, 

respectively, for Units 2, 3, and 4. EPA’s 

modeling showed a source-wide 

visibility improvement for SCR of 1.34 

dv at the most impacted Class I area. In 

comparison, the source-wide visibility 

improvements at the most impacted 

Class I area for Hunter and Huntington 

from SCR + LNB/SOFA are much larger: 

2.948 dv and 3.848 dv, respectively. 

While the average cost-effectiveness 

values at Cholla are somewhat higher 

than those for the Hunter and 

Huntington BART units, the 

incremental cost-effectiveness of SCR at 

the Hunter and Huntington BART units 

is considerably higher, at $5,830/ton to 

$6,632/ton. Despite that disparity in 

incremental cost-effectiveness, this 

comparison still supports selection of 

SCR + LNB/SOFA for the Hunter and 

Huntington BART units, given the much 

greater magnitude of the visibility 

benefits and the fact that our other 

comparisons show the incremental costeffectiveness of SCR + LNB/SOFA is 

still reasonable. Finally, Cholla Power 

Plant does impact somewhat more Class 

I areas, thirteen as opposed to nine for 

Hunter and Huntington; however, were 

we to sum the baseline impacts of 

Hunter and Huntington, they would be 

greater than those for Cholla. 

Based on these comparisons to 

Laramie River Station, Hayden Station, 

Dave Johnston Units 3 and 4, and Cholla 

Power Plant Units 2, 3, and 4, the 

selection of LNB and SOFA with SCR as 

BART for the Hunter and Huntington 

BART units is fully justified.73 For these 

four units, LNB and SOFA with SCR is 

very cost-effective, at $2,697/ton to 

$2,928/ton on an average basis 

(counting the costs and emission 

reductions from the combination of the 

three control technology elements), and 

at $5,830/ton to $6,632/ton on an 

incremental basis compared to LNB 

with SOFA and SNCR. Compared to 

LNB with SOFA, the incremental cost 

effectiveness of LNB and SOFA with 

SCR ranges from $5,206/ton to $5,861/ 

ton, which is in line with the 

incremental cost effectiveness that 

supported the selection of LNB with 

SOFA and SCR for Laramie River 

Station. For the Hunter and Huntington 

BART units, LNB and SOFA with SCR 

provides substantial visibility benefits at 

several Class I areas that are similar in 

magnitude to those from Laramie River 

Station. For example, the visibility 

improvement from that control option 

installed on a single unit is 1.342 dv at 

Arches National Park, 1.545 dv at 

Canyonlands National Park, and 1.113 

at Capitol Reef National Park. These 

comparisons show that costs are 

justified in light of the substantial 

visibility benefits, both total and 

incremental. In addition, for each unit, 

SCR + LNB/SOFA provides a significant 

improvement in the number of days 

over 0.5 dv as compared to the baseline 

(ranging from 42 days improvement at 

Hunter Unit 2 to 67 days improvement 

at Huntington Unit 1). 

As mentioned earlier, the BART 

Guidelines require consideration of the 

visibility improvement from the use of 

BART controls applied to the collection 

of emissions units that make up the 

BART source. Tables 6 and 7 summarize 

the source-wide visibility improvements 

from the installation of SCR + LNB/

SOFA at both BART units at Hunter and 

both BART units at Huntington, as well 

as the visibility improvements from the 

installation of SCR + LNB/SOFA at the 

other impacted Class I areas. 

TABLE 6—SUMMARY OF SOURCE-WIDE VISIBILITY IMPACTS AND IMPROVEMENTS FOR HUNTER

Class I area 

Baseline visibility impacts BART (SCR + LNB/SOFA) Impacts 

(Improvements over baseline shown in parentheses) 

Impacts 

(dv) Days > 0.5 dv Days > 1.0 dv Impacts 

(dv) Days > 0.5 dv Days > 1.0 dv 

Arches National Park (NP) ...................... 4.601 293 170 1.981 (2.62) 158 (135) 71 (99) 

Black Canyon NP ..................................... 1.097 68 22 0.481 (0.616) 14 (54) 1 (21) 

Bryce Canyon NP .................................... 1.833 42 22 0.811 (1.022) 20 (22) 6 (16) 

Canyonlands NP ...................................... 5.356 359 240 2.408 (2.948) 223 (136) 111 (129) 

Capitol Reef NP ....................................... 4.606 175 118 2.171 (2.435) 114 (61) 55 (63) 

Flat Tops Wilderness ............................... 1.281 77 31 0.537 (0.744) 22 (55) 1 (30) 

Grand Canyon NP ................................... 1.891 49 32 0.730 (1.161) 25 (24) 9 (23) 

Mesa Verde NP ....................................... 1.327 82 32 0.514 (0.813) 21 (61) 4 (28) 

Zion NP .................................................... 0.963 29 14 0.369 (0.594) 10 (19) 4 (10) 

Note: The baseline impacts are the combined impacts from all three units at Hunter, while the BART source is comprised of only units 1 and 

2. EPA’s evaluation of visibility under BART relies only on the visibility benefits associated with controls on the two BART units. 


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74Emission limits such as BART are required to 

be met on a continuous basis. See 70 FR 39104, 

39172 (July 6, 2005) (stating that emissions limits 

including BART are to be met on a ‘‘continuous 

basis’’ in the BART Guidelines, section V); 42 

U.S.C. 7602(k) (noting that emission limits are to be 

on ‘‘a continuous basis’’). 

75As discussed elsewhere, while we are 

approving the PM10 emission limits in SIP Section 

IX, Part H.21, we are not approving into the SIP the 

‘‘approval orders’’ (i.e., State-issued permits) that 

are referenced in SIP Section XX.D.6.d at 25 and 

29). 

76Letter from Department of Environmental 

Quality, State of Utah to EPA, DAQP–120–15 (Dec. 

10, 2015). 

TABLE 7—SUMMARY OF SOURCE-WIDE VISIBILITY IMPACTS AND IMPROVEMENTS FOR HUNTINGTON

Class I area 

Baseline visibility impacts BART (SCR + LNB/SOFA) impacts 

(improvements shown in parentheses) 

Impacts (dv) Days > 0.5 dv Days > 1.0 dv Impacts (dv) Days > 0.5 dv Days > 1.0 dv 

Arches NP ................................................ 3.887 237 146 0.848 (3.039) 67 (170) 18 (128) 

Black Canyon NP ..................................... 0.773 45 16 0.196 (0.577) 1 (44) 0 (16) 

Bryce Canyon NP .................................... 1.221 36 19 0.326 (0.895) 4 (32) 0 (19) 

Canyonlands NP ...................................... 5.130 277 175 1.282 (3.848) 89 (188) 31 (144) 

Capitol Reef NP ....................................... 3.389 131 91 0.986 (2.403) 42 (89) 9 (82) 

Flat Tops Wilderness ............................... 0.926 64 17 0.216 (0.710) 2 (62) 0 (17) 

Grand Canyon NP ................................... 1.107 40 19 0.190 (0.806) 4 (36) 0 (19) 

Mesa Verde NP ....................................... 1.115 63 22 0.261 (0.854) 0 (63) 0 (22) 

Zion NP .................................................... 0.820 21 11 0.211 (0.609) 3 (18) 0 (11) 

As can be seen from these tables, the 

baseline visibility impacts in dv at all 

nine Class I areas are large: Even at the 

least impacted Class I area, Zion 

National Park, Hunter and Huntington 

are each above the 0.5 dv threshold for 

contributing to visibility impairment. 

For Hunter, at the three most impacted 

Class I national park areas, Arches, 

Canyonlands and Capitol Reef, the 

baseline visibility impacts range from 

4.601 dv to 5.356 dv. At these three 

Class I areas, the number of days with 

impacts over 0.5 dv and 1.0 dv range 

from 175 to 359, and from 118 to 240, 

respectively. The visibility benefits of 

BART (SCR + LNB/SOFA) at the three 

Class I areas are correspondingly large, 

ranging from 2.435 dv to 2.948 dv. The 

improvement in the number of days 

over 0.5 dv and 1.0 dv at these three 

Class I areas are large as well, ranging 

from an improvement of 61 to 136 days 

in the number of days over 0.5 dv and 

63 to 129 days in the number of days 

over 1.0 dv. Even at the least impacted 

Class I area, Zion National Park, the 

visibility benefits of BART are 

significant, 0.594 dv, and 19 and 10 

days in the number of days over 0.5 dv 

and 1.0 dv, respectively. Consideration 

of these source-wide visibility benefits 

confirms that SCR + LNB/SOFA at 

Hunter is fully justified in light of its 

reasonable costs. 

For Huntington, at the three most 

impacted Class I national park areas, 

Arches, Canyonlands and Capitol Reef, 

the baseline visibility impacts range 

from 3.389 dv to 5.130 dv. At these 

three Class I areas, the number of days 

with impacts over 0.5 dv and 1.0 dv 

range from 131 to 271, and from 91 to 

175, respectively. The visibility benefits 

of BART (SCR + LNB/SOFA) at the three 

Class I areas are correspondingly large, 

ranging from 2.063 dv to 3.538 dv. The 

improvement in the number of days 

with impacts from Huntington over 0.5 

dv and 1.0 dv at these three Class I areas 

are similar to those of Hunter. 

Huntington has 89 fewer days with 

impacts over 0.5 dv at Capitol Reef, 170 

fewer days with such impacts at 

Archers, and 188 fewer days at 

Canyonlands. The number of days 

Huntington has impacts over 1.0 dv at 

these areas falls by 82 to 144 days. Even 

at the least impacted Class I area, Zion 

National Park, the visibility benefits of 

BART are significant. BART is projected 

to result in a 0.609 dv improvement at 

Zion the number of days with impacts 

over 0.5 dv and 1.0 dv fall by 18 and 

11 days, respectively. Consideration of 

these source-wide visibility benefits 

confirms that SCR + LNB/SOFA at 

Huntington, as at Hunter, is fully 

justified in light of its reasonable costs. 

Accordingly, for the Hunter and 

Huntington BART units, we find that 

BART for NOX is SCR + LNB/SOFA, 

represented by an emission limitation of 

0.07 lb/MMBtu (30-day rolling average). 

The BART emission limitation of 0.07 

lb/MMBtu allows for a sufficient margin 

of compliance for a 30-day rolling 

average limit that would apply at all 

times, including startup, shutdown, and 

malfunction.74 We are also finalizing 

our proposed monitoring, 

recordkeeping, and reporting 

requirements in our regulatory text for 

40 CFR 52.2336; these requirements will 

ensure that the BART emission 

limitation is enforceable. 

Under 40 CFR 51.308(e)(1)(iv), ‘‘each 

source subject to BART [is] required to 

install and operate BART as 

expeditiously as practicable, but in no 

event later than five years after approval 

of the implementation plan revision.’’ In 

light of the considerable effort involved 

to retrofit SCR, we determine that five 

years is as expeditiously as practicable. 

Therefore, the compliance deadline for 

the BART requirements will be five 

years from the date our final FIP 

becomes effective. 

2. PM10 BART 

We are finalizing our proposed 

approval of Utah’s PM10 BART 

determinations for Hunter Units 1 and 

2 and Huntington Units 1 and 2. We 

have determined that Utah’s PM10 BART 

determinations, emission limitations, 

and associated monitoring, 

recordkeeping and reporting for Hunter 

Units 1 and 2 and Huntington Units 1 

and 2 meet the requirements of 40 CFR 

51.309(d)(4)(vii) and the linked BART 

requirements in 40 CFR 51.308(e)(1).75

We are approving SIP Section IX, Part 

H.21 subsections a through d and f 

(related to applicability, definitions, 

recordkeeping, and stack testing), and 

conditionally approving Subsection e 

(emission limitations shall apply at all 

times). We are approving SIP Section IX, 

Part H.22 subsections a.i and b.i. We 

considered and rejected comments on 

the validity of the State’s BART analyses 

for PM10 and the State’s emission 

limitation of 0.015 lb/MMBtu on a 30- 

day rolling basis for the Hunter and 

Huntington BART units. For PM10

reporting, we are finalizing our 

proposed conditional approval of this 

element in accordance with CAA 

section 110(k)(4), based on Utah’s 

commitment to submit specific 

measures to address the reporting 

requirement.76 Utah’s letter commits to 

adopt and submit rule language that 

would require sources to report any 

deviation from the requirements of the 

regional haze SIP provisions, which 

would include the PM10 emission 

limitations. The specific language is 


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77See Memorandum from John Calcagni to EPA 

Regional Directors. ‘‘Processing of State 

Implementation Plan (SIP) Submittals’’ (July 1992), 

available at http://www3.epa.gov/ttn/oarpg/t1/

memoranda/siproc.pdf. 

78On May 19, 2015, PacifiCorp submitted late 

comments. These comments are included in the 

docket for this action and we address them in our 

RTC document. 

79Examples include: (1) The public hearing on 

FIP proposal on May 1, 2012 at the Lewis and Clark 

Library in Helena, MT; (2) the public hearing on FIP 

proposal on July 27, 2013 at the Laramie County 

Library in Cheyenne, WY; and (3) the public 

hearing on FIP proposal on October 13–14, 2011 at 

the North Dakota Department of Health Training 

Center in Bismarck, ND. 

detailed in Utah’s commitment letter. 

We did not receive any adverse 

comments on our conditional approval 

of the recordkeeping requirements for 

the PM10 emission limitations. 

Pursuant to CAA section 110(k)(4), 

the State has one year from the date of 

this action to adopt and submit the 

necessary SIP revisions for SIP Section 

IX.H.21.e. If the State does not meet its 

commitment within the one year period, 

the conditional approval is treated as a 

disapproval. EPA finds that the 

necessary SIP revisions meet EPA’s 

criteria for conditional approvals,77 as 

the revisions appear to involve a limited 

amount of technical work, are 

anticipated to be non-controversial, and 

can reasonably be accomplished within 

the length of time for the State’s 

adoption process. 

3. Enforceable Commitment SIP 

We are taking no action on Utah’s 

enforceable commitment SIP, submitted 

on October 20, 2015. In its enforceable 

commitment SIP submittal, the State 

resolved to address double counting 

certain emissions reductions from the 

Carbon power plant closure under both 

the Utah BART Alternative and the SO2

backstop trading program under 40 CFR 

51.309. As we explained in our 

proposal, we interpret our authority to 

enable us to approve enforceable 

commitment SIPs under section 

110(a)(2)(A) of the Act and other 

applicable sections as relevant (for our 

NOX BART action, this is section 169A). 

However, since we are not approving 

the State’s NOX BART Alternative SIP 

submittal, which included emissions 

reductions from the Carbon power 

plant, there is no need for the elements 

of the enforceable commitment SIP. 

Additionally, because we are not taking 

action on the enforceable commitment 

SIP package submitted on October 20, 

2015 we are not responding to 

comments on that SIP in this action. 

II. Summary and Analysis of Major 

Issues Raised by Commenters 

We received both written and oral 

comments at the public hearings we 

held in Salt Lake City. We also received 

comments by the Internet and mail. The 

full text of comments received from 

these commenters is included in the 

publicly posted docket associated with 

this action at www.regulations.gov. Our 

RTC document, which is also included 

in the docket associated with this 

action, provides detailed responses to 

all significant comments received. In 

total, we received approximately 4,900 

pages of significant comments. Later we 

provide a summary of the more 

significant comments received and a 

summary of our responses to them. Our 

RTC document is organized similarly to 

the structure presented in this section 

(e.g., Cost of Controls, BART Alternative 

CALPUFF Modeling, etc.). Therefore, if 

additional information is desired 

concerning how we addressed a 

particular comment, the reader should 

refer to the appropriate section in our 

RTC document. 

PacifiCorp, conservation 

organizations (HEAL Utah, National 

Parks Conservation Association, and 

Sierra Club) and the National Parks 

Service (NPS) submitted detailed 

comments that include new cost and 

visibility modeling information.78

Several government, tourism and 

industry organizations also submitted 

comments. Many general comments 

were made at the public hearing. We 

received approximately 400 comments 

through email and the 

www.regulations.gov Web site. We also 

received approximately 70,000 mass 

mailer comments from private citizens. 

A. General Comments 

Comment: Several commenters 

expressed concern over the 

accommodations provided at the public 

hearing. Several commented on the 

large number of attendees, and how this 

made it difficult for them to make their 

comments as well as hear those who 

were speaking. Commenters noted that 

many attendees were intimidated by the 

size of the hearing and by some of the 

other attendees, and suggested that 

many attendees left the hearing without 

commenting on the issues. There was 

concern that these departures may have 

led to an imbalance in opinions 

presented. Some commenters noted that 

some of the attendees at the hearing 

were not being cordial with the others 

and were unkind to those who 

expressed different opinions. Several 

commenters made requests for 

additional hearings, suggesting that 

additional hearings be located closer to 

the affected Class I areas and at 

locations that could accommodate a 

larger number of attendees. 

Response: Several commenters 

expressed their dissatisfaction with 

EPA’s public hearing arrangements. As 

required by section 307(d)(5) of the CAA 

the EPA provided an opportunity for the 

public to submit written comments and 

voice concerns at the public hearing. In 

arranging the logistics for the public 

hearing, EPA’s intent was to provide an 

opportunity for all members of the 

public to voice their opinions about the 

proposed rulemaking. The Salt Lake 

City library was chosen as the public 

hearing site because: (1) The library had 

reasonable accommodations to hold 

approximately 100 attendees; (2) the 

library was centrally located, and would 

be convenient for many members of the 

public to access; and (3) the library did 

not require a fee. The size of the venue 

was consistent with other hearings the 

EPA has conducted across the 

country.79 Based on these 

considerations, the EPA had no reason 

to believe the venue could not 

accommodate the anticipated level of 

public participation or that it would not 

fulfill the purposes of and the Act’s 

requirements for the hearing. 

While the number of individuals 

attending the public hearing exceeded 

what we anticipated, we made 

adjustments throughout the day to 

accommodate the large numbers. For 

example, the library staff worked with 

us and set up broadcast speakers in the 

hallway so that those in the hallway 

could hear what was said during the 

hearing. The EPA could not allow the 

meeting room used for the public 

hearing to exceed its capacity limit in 

order to comply with the library’s 

policies to comply with the fire code 

occupancy requirements. In response to 

the unkind statements made by some 

participants, the Hearing Officer 

reminded the crowd that the purpose of 

the meeting was to allow people to 

testify comfortably without being 

intimidated, and that people causing 

distractions would be asked to leave. In 

fact, some attendees who were causing 

distractions were asked to leave. 

Additionally, even though the turnout 

was larger than expected, EPA 

scheduled the opportunity for the 

public to speak based on their arrival 

time (with those arriving first, first 

allowed to speak); and the EPA 

accommodated all the potential 

speakers at the end of the scheduled 

hearing time, by extending the hearing 

until everyone who was present at that 

time and wanted to speak had done so. 

As a result the hearing was extended by 

approximately 20 minutes. 


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80 81 FR 2004 (Jan. 14, 2016). 

81 64 FR 35714, 35739 (July 1, 1999). 

82 Id. (emphasis added). 

83 81 FR 2004, 2006 (Jan. 6, 2016) (citing 71 FR 

60612, 60621 (Oct. 13, 2006)). 

84 42 U.S.C. 7491(a)(1). 

85H.R. Rep. No. 95–294, at 137 (1977). 

The EPA determined that additional 

hearings were unnecessary, because the 

written comment period continued for 

approximately seven weeks after the 

public hearing, allowing for additional 

comments to be submitted. As 

explained in the proposed rule,80 in 

addition to the public hearing, the EPA 

accepted written comments provided 

those comments were received on or 

before March 14, 2016. Therefore, while 

some of the members of the public may 

have left before they had an opportunity 

to speak at the hearing, they still had the 

opportunity to submit their comments 

either online or via mail to EPA for 

approximately seven weeks after the 

public hearing, as demonstrated in 81 

FR 2004. The EPA gives just as much 

consideration to comments we receive 

in writing as we do to those we receive 

at public hearings. 

B. EPA Authority and State Discretion 

Comment: The State of Utah 

commented that EPA should approve its 

BART Alternative because it meets all of 

the current requirements of the CAA 

and the RHR found at 40 CFR 51.300 

through 51.309. EPA is obligated to 

approve a SIP that meets all of the 

applicable requirements of the CAA. See 

42 U.S.C. 7410(k)(3) (‘‘In the case of any 

submittal on which the Administrator is 

required to act under paragraph (2), the 

Administrator shall approve such 

submittal as a whole if it meets all of the 

applicable requirements of this 

chapter.’’). The Section 308 regulation 

grants states full discretion as to 

whether to adopt the BART Alternative. 

In the current proposed rule, EPA also 

acknowledges a state’s discretion in 

approving alternative measures: Finally, 

in . . . responding to concerns 

regarding ‘‘impermissibly vague’’ 

language in § 51.308(e)(3) that would 

allow a State to ‘‘approve alternative 

measure that are less protective than 

BART,’’ we explained that ‘‘[t]he State’s 

discretion in this area is subject to the 

condition that it must be reasonably 

exercised and that its decision be 

supported by adequate documentation 

of its analyses.’’ 81 FR 2004, 2012 

(quoting 71 FR 60612, 60621 (Oct. 13, 

2006)). Therefore, the alternative 

measure is within the state’s discretion, 

as long as it is adequately supported. 

Response: We agree that states have 

discretion to adopt BART alternatives; 

however, as the commenter explains, 

the state’s discretion is subject to a 

number of requirements, including that 

it be reasonably exercised and 

adequately supported and that the 

state’s Alternative clearly provides 

greater reasonable progress than BART. 

The CAA requires that states submit 

SIPs that contain such measures as may 

be necessary to make reasonable 

progress toward achieving natural 

visibility conditions, including the 

BART requirements. As EPA explained 

when promulgating the regional haze 

regulations, ‘‘[t]he overarching 

requirement of the visibility protection 

provisions of section 169A is to make 

reasonable progress toward the national 

goal of eliminating visibility 

impairment. If greater reasonable 

progress can be made through an 

approach that does not require source 

specific application of BART, EPA 

believes that approach would comport 

with this statutory goal.’’ 81 States have 

the opportunity to adopt alternative 

measures in lieu of BART where the 

agency reasonably concludes that more 

reasonable progress will thereby be 

attained toward the national visibility 

goal.82 We explained these requirements 

in our co-proposal as follows: ‘‘[a]s 

described in our 2006 revisions to the 

RHR, concerning BART alternatives, 

‘[t]he State’s discretion in this area is 

subject to the condition that it must be 

reasonably exercised and that its 

decisions be supported by adequate 

documentation of its analyses.’ ’’83

While states have discretion to decide 

whether to adopt a BART alternative in 

a SIP, such discretion does not extend 

to the authority to adopt SIPs that will 

not ensure reasonable progress toward 

the national visibility goal of preventing 

any future and remedying of any 

existing visibility impairment in Class I 

areas. Such an interpretation is also 

inconsistent with the legislative history, 

which stresses the importance of the 

‘‘national goal’’ 84 of clear air quality in 

Class I areas and ‘‘preventing 

impairment of visibility,’’ noting that 

‘‘the millions of Americans who travel 

thousands of miles each year to visit 

Yosemite or the Grand Canyon or the 

North Cascades will find little 

enjoyment if . . . upon reaching the 

Grand Canyon it is difficult if not 

impossible to see across the great 

chasm.’’ 85

Thus, we do not agree that Congress 

assigned states full discretion in 

developing SIPs, because it is not clear 

how EPA’s limited role under such a 

scenario would assure attainment of the 

national goal or imposition of the [better 

than] BART requirements where a 

state’s BART alternative demonstration 

does not demonstrate that the 

alternative achieves greater reasonable 

progress. In view of the statutory 

requirements, it is logical that EPA 

would evaluate the reasonableness of 

the State’s BART Alternative analysis in 

light of the purpose of the regional haze 

program. 

As detailed in the sections in our coproposal and based on our evaluation 

and findings as detailed in Section I.B.1 

of this document and in our RTC 

document, we determined that, on 

balance, the evidence does not show 

that the Alternative clearly achieves 

greater visibility benefits than BART. 

Because the State’s BART Alternative is 

not approvable, we are obligated to 

disapprove it, develop BART analyses, 

and then arrive at our own BART 

determinations for the four EGUs that 

are subject-to-BART. 

Furthermore, this is a SIP review 

action, and we believe that EPA is not 

only authorized, but required to exercise 

independent technical judgment in 

evaluating the adequacy of the State’s 

regional haze SIP, including its BART 

Alternative analyses, just as EPA must 

exercise such judgment in evaluating 

other SIPs. In evaluating other SIPs, 

EPA is constantly exercising judgment 

about SIP adequacy, not just to meet and 

maintain the NAAQS, but also to meet 

other requirements that do not have a 

numeric value. In this case, Congress 

did not establish a specific numeric 

value by which to measure visibility 

improvement; instead, it established a 

reasonable progress standard and 

required that EPA assure that such 

progress be achieved via 

implementation, inter alia, of the Act’s 

BART requirement. Here, we are 

exercising judgment within the 

parameters laid out in the CAA and our 

regulations. 

Our evaluation of the State’s BART 

Alternative is presented in section I.B.1 

and in our RTC document. 

Comment: The State commented that 

EPA mistakenly imposes additional 

inapplicable requirements in its 

evaluation of Utah’s regional haze SIP. 

Greater reasonable progress under 

Section 308(e)(2) can be demonstrated 

using either one of two methods: (1) 

Greater emission reductions than under 

BART (Section 308(e)(3)); or (2) the 

weight-of-evidence test, consisting of a 

number of requirements that the state 

weighs to conclude which option 

achieves greater reasonable progress 

(section 308(e)(2)). See 40 CFR 

51.308(e)(2) and (3). The state has 

discretion to choose one method over 

the other. See WildEarth Guardians v. 

E.P.A., 770 F.3d 919, 935–37 (10th Cir. 


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86 81 FR 2004, 2028 (‘‘Therefore, we propose to 

disapprove Section XX.D.6.c. of the Utah SIP under 

the test in 40 CFR 51.308(e)(3).’’). 

87EPA’s interpretation of the requirement under 

40 CFR 51.308(e)(3) that the alternative measure 

‘‘results in greater emission reductions’’ has been 

that the emission reduction comparisons are 

pollutant specific. We have applied this 

interpretation in evaluating BART alternatives and 

we have not looked at a total emissions profile that 

combines emissions of multiple pollutants to 

determine whether a BART benchmark or a BART 

alternative is ‘‘better,’’ except where every visibility 

impairing pollutant is reduced by a greater amount 

under the BART alternative. See 79 FR 9318, 9335 

(Feb. 18, 2014) (proposed approval of Arizona 

BART Alternative for Sundt Unit 4); 79 FR 52420 

(Sept. 3, 2014) (final approval of Arizona BART 

Alternative for Sundt Unit 4); 77 FR 18052, 18073– 

75 (Mar. 26, 2012) (proposed approval of Colorado 

BART Alternative, no modeling required where the 

40 CFR 51.308(e)(3) test was met); 77 FR 76871 

(Dec. 31, 2012) (final approval of Colorado BART 

Alternative). EPA has not relied on a total emissions 

profile that combines emissions of multiple 

pollutants together to determine that either BART 

or a BART alternative is ‘‘better,’’ because visibility 

modeling is the most appropriate method to assess 

the overall improvements in visibility impacts from 

control scenarios where reductions of multiple 

pollutants are considered, except where every 

visibility impairing pollutant is reduced by a greater 

amount under the alternative. As we have 

explained, ‘‘[e]ach of the five pollutants which 

cause or contribute to visibility impairment has a 

different impact on light extinction for a given 

particle mass, making it therefore extremely 

difficult to judge the equivalence of interpollutant 

trades in a manner that would be technically 

credible, yet convenient to implement in the 

timeframe needed for transactions to be efficient. 

This analysis is further complicated by the fact that 

the visibility impact that each pollutant can have 

varies with humidity, so that control of different 

pollutants can have markedly different effects on 

visibility in different geographic areas and at 

different times of the year.’’ See 64 FR 35714, 

35743(July 1, 1999). As other Agency actions on 

BART alternatives have explained, modeling 

assesses ‘‘both pollutants’ chemical aerosol 

formation mechanisms and impacts on visibility,’’ 

(see 78 FR 79344, 79355; Dec. 30, 2013) which 

allows evaluation of the ‘‘relative visibility impacts 

from the atmospheric formation of visibility 

impairing aerosols of sulfate and nitrate.’’ See 79 FR 

33438, 33440 (June 11, 2014). 

88EPA is well aware that the Utah SIP, as it has 

been implemented over time, became binding state 

law in regard to the Utah BART Units and 

ultimately the other units covered by the BART 

Alternative. This makes it particularly egregious 

that, even though EPA knew that PacifiCorp was 

required to expend hundreds of millions of dollars 

to fully implement the BART Alternative under 

state law, EPA said nothing about its intention to 

issue a competing co-proposal until after PacifiCorp 

had completed all of the emission reductions 

required under the Utah SIP. See Letter from Carl 

Daly to Bryce Bird, Re. EPA Region 8 Comments on 

Utah’s February 2015 Draft Regional Haze SIP 

Revision, at 1 (May 1, 2015) (commenting on the 

then-proposed Utah SIP including the BART 

Alternative). This secretive approach by EPA also 

caught the Utah Division of Air Quality off guard 

as explained in their oral comments during the 

January 26, 2016 hearing: ‘‘Throughout the SIP 

development process, we worked as regulatory 

partners, closely and extensively with EPA staff to 

ensure that Utah’s Alternative to BART SIP revision 

met all the requirements of the Clean Air Act and 

was approvable by EPA. The EPA should approve 

the option that Utah developed while in close 

consultation with EPA and not the option that Utah 

was not even aware was being prepared or under 

consideration until it was proposed in the Federal 

Register.’’ 

89See CAA sections 169A and 110(k)(3). 

2014). The Tenth Circuit characterized 

the former approach as ‘‘quantitative’’ 

and the latter as ‘‘qualitative,’’ 

ultimately ruling that EPA can properly 

rely on qualitative factors in applying 

the ‘‘weight-of-evidence test.’’ See id. at 

934–35 (EPA’s choice of qualitative 

standard was ‘‘permissible under the 

EPA’s interpretation of its 

regulations.’’). 

Utah submitted its BART Alternative 

under Section 308(e)(2), purposefully 

electing to make its determination that 

the alternative program achieves greater 

reasonable progress under the ‘‘weightof-evidence’’ test. EPA analyzed Utah’s 

BART Alternative in both co-proposals 

under the section 308(e)(3) ‘‘greater 

emissions reductions test’’ in addition 

to the ‘‘weight-of-evidence’’ analysis. 

See 81 FR 2004, 2021, 2028. EPA 

proposed that Utah’s BART Alternative 

does not result in greater emission 

reductions because ‘‘the total NOX

emissions are greater under the BART 

Alternative than the BART Benchmark,’’ 

even though ‘‘in the aggregate there are 

fewer SO2 and PM10 emissions for the 

BART Alternative . . . .’’ Id. at 2028. 

EPA erroneously imposed Section 

308(e)(3) requirements on Utah’s BART 

Alternative in addition to the Section 

308(e)(2) weight-of-evidence test. EPA 

must withdraw its analysis of Utah’s 

BART Alternative under the greater 

emissions reductions test because, as 

Utah clearly explained, the State never 

intended its data to satisfy this test. 

Response: We agree in part and 

disagree in part with this comment. In 

developing a BART Alternative SIP, we 

agree that a state has the discretion to 

choose between the ‘‘greater emission 

reduction’’ test (section 308(e)(3)) and 

the ‘‘weight-of-evidence’’ test (section 

308(e)(2)). Utah’s comments clarify that 

they elected the weight-of-evidence test, 

and so we clarify and modify our 

evaluation of the State’s SIP submittal. 

We therefore clarify that we are not 

disapproving the SIP under the 

elements of the section 308(e)(3) test as 

we had proposed.86

The State’s submittal, however, 

asserted that the BART Alternative is 

better than BART based in part on the 

metric that compared annual emissions 

of the three visibility impairing 

pollutants in the aggregate. There is no 

requirement in section 308(e)(2) for the 

State to compare annual emissions of 

visibility pollutants in the aggregate. 

Rather, as we explained in our proposal, 

we have addressed this issue under 

section 308(e)(3); our interpretation 

under that provision also applies under 

section 308(e)(2). Specifically, if under 

section 308(e)(2) a state compares 

annual emissions of visibility in the 

aggregate to determine whether a BART 

alternative ‘‘results in greater emission 

reductions,’’ we examine whether each 

of the visibility causing pollutants is 

less under the alternative. For the 

reasons explained in our proposal and 

in section I.B.1.c.i of this document, we 

have not approved a BART alternative 

where one or more of the specific 

pollutants under the BART alternative is 

greater than it would be under the 

BART benchmark.87

Therefore, as we did in our proposal, 

it is reasonable to apply our 

interpretation of the section 308(e)(3) 

‘‘greater emission reductions’’ element 

under section 308(e)(2) as well, because 

the same concerns regarding the 

relationship between reductions of 

multiple pollutants and visibility 

improvements are also relevant in the 

weight-of-evidence context. 

Comment: PacifiCorp asserted that 

EPA is not empowered under the CAA 

to require compliance with both the SIP 

proposal and the FIP proposal. As a 

practical matter, that is precisely what 

EPA proposes to do to the extent it 

approves the FIP proposal. This is 

because PacifiCorp already has 

implemented the SIP proposal as 

required by Utah law. If EPA were to 

select the FIP proposal, it would do so 

knowing 88 that PacifiCorp would be 

required to implement both the SIP 

proposal and the FIP proposal. Nothing 

in CAA or regional haze rules allows 

EPA to require such a result when the 

proposed action itself states that EPA 

‘‘intends to finalize only one proposal.’’ 

See 81 FR 2004, 2006. 

For all of the reasons stated earlier, 

EPA should approve the Utah SIP as 

stated in the SIP proposal, and should 

reject the FIP proposal. What EPA 

cannot do, and indeed is not 

empowered under the CAA to require, 

is compliance with both the SIP 

proposal and the FIP proposal. 

Response: We disagree with this 

comment. As explained elsewhere, the 

CAA requires that states submit SIPs 

that contain such measures as may be 

necessary to make reasonable progress 

toward achieving natural visibility 

conditions, including the BART 

requirements. EPA is acting under its 

authority pursuant to the CAA in 

disapproving portions of the SIP 

submittal and promulgating the FIP. We 

have the duty to ensure that regional 

haze SIP submittals meet the 

requirements of the Act and the RHR.89

While states have the opportunity to 

adopt alternative measures in lieu of 


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90Rebuttal Testimony of Cathy S. Woolums, at 26. 

(June 30, 2011). (Available in the docket at https:// 

www.regulations.gov/#!documentDetail;D=EPAR08-OAR-2015-0463-0167). 

91Utah’s Effective rule explains that ‘‘[w]hile 

Utah has chosen to meet the NOX BART 

requirement through alternative measures . . . the 

enforceable emission limits for both NOX and SO2

established in the approval orders and in the SIP 

for the four EGUs also met the presumptive 

emission rates for both NOX and SO2 established in 

Appendix Y independently of the alternative 

program.’’ Effective Rule at page E–12, Section XX, 

p. 168 (adopted by the Board on June 3, 2015), 

available in the docket at https://

www.regulations.gov/#!documentDetail;D=EPAR08-OAR-2015-0463-0002. The presumptive 

emission limits in the BART Guidelines are 

rebuttable. The presumptive emission limits apply 

to power plants with a total generating capacity of 

750 MW or greater insofar as these sources are 

required to adopt emission limits at least as 

stringent as the presumptive limits, unless after 

considering the five statutory factors, the State 

determines that the presumptive emission limits are 

not appropriate. 

92Congress required EPA to promulgate 

regulations to assure ‘‘reasonable progress’’ toward 

meeting the national goal and compliance with 

section 169A. The regulations require the 

submission of regional haze SIPs for states with 

Class I areas within their borders and states whose 

emissions ‘‘may reasonably be anticipated to cause 

or contribute to any impairment of visibility’’ in a 

Class I area outside their borders. 42 U.S.C. 

7491(b)(2), 7491(e)(2). All SIPs must include 

‘‘enforceable emission limitations and other control 

measures, means, or techniques . . . as well as 

schedules and timetables for compliance, as may be 

necessary or appropriate to meet the applicable 

requirements of [the Act].’’ CAA section 

110(a)(2)(A). Regional haze SIPs must include 

emission limits, compliance schedules, and other 

measures ‘‘as may be necessary to make reasonable 

progress toward meeting the national goal.’’ 42 

U.S.C. 7491(b)(2). 

93Letter from Carl Daly to Bryce Bird, Re. EPA 

Region 8 Comments on Utah’s February 2015 Draft 

Regional Haze SIP Revision, at 1 (May 1, 2015). 

(Available in the docket at https://

www.regulations.gov/#!documentDetail;D=EPAR08-OAR-2015-0463-0160). 

94As explained below [referring to PacifiCorp’s 

comment document], EPA is simply wrong in 

concluding that Utah used two separate approaches 

to demonstrate greater reasonable progress. 

Therefore, EPA’s stated basis for imposing the 

Reasonableness Standard does not support EPA’s 

effort to do so. 

BART, their discretion in this area is 

subject to the condition that it must be 

reasonably exercised and that their 

decisions be supported by adequate 

documentation of its analyses. 

Therefore, we do not agree that we are 

prohibited from identifying deficiencies 

in the Utah SIP submittal after the State 

rulemaking process is complete, and the 

commenter cites nothing in the Act to 

the contrary. While a state may adopt 

regulations that are effective as a matter 

of state law before EPA goes through its 

rulemaking process to evaluate the 

proposed SIP elements, those state rules 

are not federally enforceable because 

any SIP submittal ‘‘shall not be treated 

as meeting the requirements of this 

chapter until the Administrator 

approves the entire plan revision as 

complying with the applicable 

requirements.’’ 42 U.S.C. 7410(k)(3). 

The State’s and EPA’s roles in this 

process were understood in PacifiCorp 

statements. For example, in response to 

a question provided during rebuttal 

testimony that asked whether the 

regional haze rules are final, the 

Company explained that the 2011 Utah 

and Wyoming SIP submittals ‘‘are final 

insofar as state action is considered’’ 

and recognized that ‘‘these submittals 

have not yet been approved by the 

Environmental Protection Agency.’’ 90

The commenter suggests that 

measures in Utah’s SIP submittal 

became ‘‘binding state law in regard to 

the Utah BART Units’’ and ‘‘the other 

units covered by the BART Alternative’’ 

prior to EPA’s final action. The 

commenter merely suggests there are 

state law provisions but does not 

provide citations to any state law 

specific provisions.91 It appears, 

however, that the commenter may be 

referring to measures established 

pursuant to the State’s permit process. 

If this is, indeed, what the commenter 

is referring to, both the CAA and our 

regulations require that emission limits 

be established pursuant to a BART or 

BART alternative determination, and be 

contained in an EPA-approved SIP.92

The fact that Utah chose to use its 

permit process to establish emission 

limits for its BART sources before EPA 

completed its review of the State’s SIP 

submittal has no bearing on EPA’s 

authority and obligation to conduct this 

review and to approve or, if necessary, 

disapprove the State’s submittal. 

Finally, EPA’s comment letter on the 

State’s proposed SIP clearly explained 

that ‘‘we will only come to a final 

conclusion regarding the regional haze 

program for Utah when we take action 

on the program through our own public 

notice-and-comment rulemaking.’’ 93

Our letter further explained to the State 

that, ‘‘we are working towards meeting 

our legal obligations that have resulted 

from our January 2013 partial 

disapproval action for Utah’s May 2011 

regional haze SIP.’’ EPA comment 

letters are intended to help improve any 

SIP revision that is under development, 

but they do not constitute agency action 

on that SIP revision or constitute any 

assurance of positive action on that 

revision upon submission and review. 

Instead and always, EPA has to formally 

discharge its responsibilities to review 

any SIP submittal. Moreover, the CAA 

does not require EPA to participate in 

state proceedings related to a state’s SIP 

submission, nor does it preclude EPA 

from carrying out its statutory duty to 

disapprove an inadequate SIP if EPA 

does not voice concerns during state 

proceedings. The CAA requires EPA to 

issue a FIP when states have not met 

their obligations under the CAA. 

Therefore, EPA is promulgating this FIP 

to fill the regulatory gap created by the 

partial disapproval of Utah’s SIP 

submittals. Despite the existence of a 

FIP, the State retains its authority to 

submit future regional haze SIPs 

consistent with CAA and RHR 

requirements; we do not discount the 

possibility of a future, approvable SIP 

submission that results in the 

modification or withdrawal of the FIP. 

C. Reasonableness Standard 

Comment: One commenter asserted 

that EPA arbitrarily and capriciously 

applies two inappropriate standards to 

the Utah SIP proposal. The commenter 

stated that, in an attempt to replace 

Utah’s determination with its own, EPA 

imposes a ‘‘Reasonableness Standard’’ 

without concluding the Utah SIP 

contains data or methodological flaws— 

the limited circumstances under which 

courts have upheld use of this 

standard—and also imposes a 

‘‘Complexity of Evaluation’’ standard 

which finds no support in the CAA or 

applicable regulations. 

The commenter also asserted that EPA 

is prohibited from imposing additional 

requirements upon its approval/

disapproval of a SIP that do not qualify 

as ‘‘applicable requirements.’’ EPA is 

not correct in its attempt in the 

proposed action to impose additional 

requirements on its evaluation of the 

BART Alternative and Utah SIP that are 

different than the applicable BART 

alternative requirements. 

1. Reasonableness Standard –EPA 

asserts that Utah ‘‘has several options 

for making the greater reasonable 

progress determination [and it] elected 

to use two separate approaches.’’ 94 See 

81 FR at 2006. EPA further states that 

it will evaluate both of those approaches 

in deciding whether to approve the Utah 

SIP. EPA then makes the blanket 

assertion that ‘‘the State’s discretion in 

this area is subject to the condition that 

it must be reasonably exercised and that 

its decisions be supported by adequate 

documentation of its analysis.’’ 

(‘‘Reasonableness Standard.’’) See 81 FR 

at 2006. Although the use of words like 

‘‘reasonable’’ and ‘‘adequate’’ have 

common sense appeal in the abstract, 

EPA may not apply this standard in a 

way that allows EPA to discard the 

state’s discretion and instead impose 

EPA’s own will. 

In addition, the present circumstances 

regarding the SIP proposal are far 

different than those circumstances in 


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95See generally 81 FR 2004, 2021–26. 

96This is not to say that EPA lacks any role in 

reviewing and approving the Utah SIP. Indeed, the 

latest court to weigh in on EPA’s review authority 

makes clear that ‘‘Congress intended that EPA, not 

the states alone, ultimately ensure that state 

determinations as to regional haze comply with the 

[Clean Air] Act. . ..’’ Arizona ex rel. Darwin v. 

EPA, Nos. 13–70366, 13–70410, 2016 U.S. App. 

LEXIS 3196, at *19–20 (9th Cir. Feb. 24, 2016). 

Although PacifiCorp agrees that EPA has a role to 

play in making sure the Utah SIP complies with the 

CAA and applicable requirements, it also notes that 

EPA must do so in a way that does not undermine 

the role of states like Utah to which ‘‘Section 169A 

[of the CAA] gives. . .substantial responsibility in 

determining appropriate BART [and BART 

Alternative] controls.’’ The court goes on to make 

clear that ‘‘EPA may not disapprove reasonable 

state determinations that comply with the relevant 

statutory and regulatory requirements.’’ Id. at *22. 

Such is the case with the Utah SIP. 

97EPA attempts to further support this contrived 

‘‘complexity’’ requirement by repeatedly stating 

that such a requirement exists, as if repetition alone 

somehow can bring an imaginary requirement into 

existence (i.e., ‘‘In light of the variety of metrics 

Utah used, this is a complicated analysis. . . ;’’ 

‘‘The complexity of our evaluation leads us to 

propose and solicit comments on two conclusions 

and two courses of action . . . ;’’ ‘‘Given the 

complexities in evaluating these co-proposals, EPA 

wants to ensure that our final decision is based on 

the best and most currently available data and 

information, and is taken with the fullest possible 

consideration of public input.’’) See 81 FR 2004, 

2006. 

98The Tenth Circuit Court of Appeals, which 

considered whether EPA’s approval of a BART 

Alternative for SO2 emissions was appropriate, did 

not conclude that EPA’s analysis of the alternative 

program was, by its nature, more complicated than 

a BART analysis. See generally WildEarth 

Guardians v. EPA, 770 F.3d 919 (10th Cir. 2014). 

99EPA further attempts to justify its rationale for 

considering the FIP proposal by asserting, as 

explained in footnote 3, the need to ‘‘ensure that 

our final decision is based on the best and most 

currently available data and information, and is 

taken with the fullest possible consideration of 

public input.’’ EPA already is charged with 

ensuring that any final decision is based on the best 

current data and information available. See 71 FR 

60612, 60622 (Oct. 13, 2006) (final rule on revisions 

to provisions governing alternative source-specific 

BART determinations); see also 5 U.S.C. 706(2). 

EPA already is required to make a decision based 

on the fullest possible consideration of public 

input. See 5 U.S.C. 553(c). Re-stating these 

fundamental principles does not allow EPA to 

bootstrap itself into also considering a competing 

coproposal (the FIP proposal) when the SIP 

proposal already meets all Applicable BART 

Alternative Requirements as EPA itself has 

proposed to conclude. Arizona ex rel. Darwin at *22 

(stating that ‘‘EPA may not second-guess reasoned, 

legally compliant state decisions’’) (internal 

citations and quotations omitted). 

100 81 FR 2004, 2006 (Jan. 14, 2016) (emphasis 

added). 

which courts have upheld EPA’s use of 

a similar Reasonableness Standard in 

other regional haze settings. For 

example, in North Dakota v. EPA, 730 

F.3d 750, 760 (8th Cir. 2013), the court 

allowed EPA’s use of the 

Reasonableness Standard under those 

circumstances where the state’s BART 

determination contained ‘‘data flaws 

that led to an overestimated costs of 

compliance.’’ Also, Oklahoma v. EPA, 

723 F. 3d 1201, 1212 (10th Cir. 2013) 

reached a similar conclusion based on 

‘‘methodological flaws.’’ 

In the case of the SIP proposal, 

however, EPA proposes to approve the 

BART Alternative based on compliance 

with the applicable BART alternative 

requirements 95 and without also 

concluding that the BART Alternative 

contains ‘‘data flaws’’ or 

‘‘methodological flaws.’’ Therefore, the 

factual bases for allowing EPA to apply 

a Reasonableness Standard do not exist 

in regard to the BART Alternative and 

EPA should not attempt to apply such 

a standard here—particularly as a basis 

for rejecting the BART Alternative.96

2. Complexity of Evaluation 

Standard—EPA also is wrong in its 

attempt to count among applicable 

requirements the unsupported 

conclusion that the ‘‘complexity of our 

evaluation’’ somehow necessitates EPA 

soliciting comments not only on the SIP 

proposal, but also on the competing FIP 

proposal. See 81 FR 2006.97 Even taking 

at face value the assertion that analyzing 

the Utah SIP is ‘‘complicated,’’ that 

alone does not require EPA to evaluate 

the Utah SIP differently than any other 

regional haze SIP, nor does it justify 

EPA in presenting dueling coproposals.98 In other words, EPA has 

simply conjured up this new 

‘‘complexity’’ requirement 99 out of thin 

air in an attempt to support its offering 

of the competing FIP proposal. EPA is 

acting arbitrarily and without legal 

authority by seeking comment on the 

FIP proposal based on what EPA calls 

the ‘‘complexity of our evaluation’’ and 

for this reason EPA should withdraw 

the FIP proposal and approve the SIP 

proposal as proposed. 

Response: We disagree with most of 

these comments. First, we disagree that 

we have used a ‘‘reasonableness 

standard’’ in a manner that is 

inconsistent with our prior actions or as 

a way to limit the State’s discretion. As 

discussed elsewhere, EPA has a duty to 

review Utah’s regional haze SIP, 

including its BART Alternative, for 

compliance with the applicable 

requirements of the CAA and the RHR. 

Based on our review of the SIP, we 

proposed to determine that certain 

elements of Utah’s regional haze SIP 

met the applicable requirements, and 

we proposed to approve those elements. 

However, for the reasons explained in 

detail in our proposed action and 

elsewhere in this document, we have 

concluded that, with regard to other 

elements, the State did not exercise its 

discretion in a reasonable manner, i.e., 

in a manner consistent with the 

requirements and goals of the CAA and 

RHR. Based on these findings, we are 

required to partially disapprove Utah’s 

regional haze SIP submittal. 

As discussed in detail elsewhere, the 

CAA provides EPA with the authority to 

review and reject an inadequate regional 

haze SIP submittal. Oklahoma v. EPA, 

723 F.3d 1201, 1207–08 (10th Cir. 2013) 

(EPA may not approve a submittal that 

does not adhere to applicable statutory 

and regulatory requirements). Contrary 

to the commenter’s assertions, our 

analysis and decision here is entirely 

consistent with the North Dakota and 

Oklahoma decisions. The RHR requires 

a state to demonstrate that its BART 

alternative achieves greater reasonable 

progress than BART, 40 CFR 

51.308(e)(2), and Utah chose to make 

this demonstration using a weight-ofevidence analysis. In our review, EPA 

found a number of flaws in this 

analysis. Based on this evaluation and 

findings as detailed in Section I.B.1 of 

this document and in our RTC 

document, we determined that, on 

balance, the evidence does not show 

that the Alternative clearly achieves 

greater visibility benefits than BART. 

Second, we disagree with the 

assertions regarding creation of a new 

complexity standard. The commenter 

misunderstands and misconstrues our 

proposed action. We did not create a 

new complexity standard, rather we 

explained that we were considering 

complex information and that it was a 

close call for EPA to decide whether the 

evidence presented by the State clearly 

demonstrated that the BART Alternative 

would achieve greater reasonable 

progress than BART (the complexity of 

our evaluation leads us to propose and 

solicit comment on two conclusions and 

courses of action because several of the 

metrics appear to support the State’s 

analyses, while others do not appear to 

support the Alternative).100 Contrary to 

the commenter’s assertions, we merely 

explained that the information in the 

State’s SIP submittal was complex; we 

did not create a new standard by which 

to evaluate SIP submittals. Our 

proposed action clearly explained that 

some metrics appeared to support 

approval, while others metrics appeared 

to support a disapproval. 

Therefore, given that EPA’s evaluation 

of the information before us presented a 

close call, and in order to provide a fair 

and meaningful process for all members 

of the public, we used the co-proposal 

approach. This approach provided an 

opportunity for the public to comment 

on both potential courses of action, i.e., 

approval or disapproval of the State’s 

BART Alternative. Recognizing the 


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101Our proposal evaluated the State’s use of the 

information from the metrics and identified 

weaknesses and flaws, for example: (1) The State’s 

characterization of the 98th percentile modeling 

results that did not support its BART Alternative, 

was inconsistent with EPA’s interpretation of and 

reliance on that metric; (2) the comparison of the 

results from the total annual emissions reductions 

was inconsistent with how we have interpreted our 

regulations; (3) the results from the modeling for the 

number of days the Alternative provided significant 

visibility impairment showed mixed results, with 

some results favoring the Alternative, while other 

results did not support the Alternative; (4) the 

annual average metric only marginally supported 

the Alternative, and showed less or equal visibility 

at four of nine Class I areas; and (5) the energy and 

non-air quality and cost metrics do not have a direct 

bearing on whether the Alternative achieves greater 

reasonable progress. 

102Our RTC document provides details on the 

additional weaknesses and uncertainties that 

commenters brought to our attention. 

103 ‘‘As explained in our proposed rulemaking for 

section 51.309(d)(4)(viii), we explained that the 

provision ‘is intended to clarify that if EPA 

determines that the SO2 emission reductions 

milestones and backstop trading program submitted 

in the section 51.309 SIP makes greater reasonable 

progress than BART for SO2, this will not constitute 

a determination that BART for PM or NOX is 

satisfied for any sources which would otherwise be 

subject to BART for those pollutants’ (emphasis 

added). 70 FR 44169 (Aug. 1, 2005). EPA does not 

interpret this rule to mean that there are different 

BART requirements for section 308 and 309 

regional haze SIPs. EPA’s rulemaking made no 

finding that BART determinations conducted for a 

state submitting a SIP under section 51.309 should 

be conducted any differently than a state submitting 

a FIP under only section 308. The use of the word 

‘necessary’ in section 51.309(d)(4)(viii) was to 

explain that some states may have BART NOX

emission limitations, while others may not. As 

already explained elsewhere in proposal and our 

response to other comments, Wyoming did not 

conduct a proper evaluation of the five statutory 

factors, as required by 40 CFR 51.308(e)(1)(ii)(A) 

and section 169A(g) of the CAA. 

EPA also disagrees with the commenter’s 

assertion that a BART submission is discretionary. 

40 CFR 51.309(d)(4)(viii) is clear in that the 

implementation plan ‘must’ contain BART 

requirements. The proposed rulemaking explained 

that the provision that provides that ‘[a]ny such 

BART provisions may be submitted pursuant to 

either Section 51.308(e)(1) or 51.308(e)(2),’ was 

included to ‘allow States the flexibility to address 

these BART provisions either on a source-by-source 

basis under Section 51.308(e)(1), or through an 

alternative strategy under Section 51.308(e)(2).’ 70 

FR 44169 (Aug. 1, 2005). 

Moreover, EPA’s proposal made clear that ‘[i]n 

limited circumstances, it may be possible for a State 

to demonstrate that an alternative program which 

controls only emissions from SO2 could achieve 

greater visibility improvement than application of 

source-specific BART controls on emissions of SO2,

NOX and/or PM. We nevertheless believe that such 

a showing will be quite difficult to make in most 

geographic areas, given that controls on SO2

emissions alone in most cases will result in 

increased formation of ammonium nitrate particles.’ 

70 FR 44169 (Aug. 1, 2005). Wyoming’s RH SIP 

does not include a demonstration that the backstop 

SO[2] trading program under Section 51.309 

achieves greater visibility improvement than 

application of source-specific PM BART controls. 

Therefore, Wyoming’s Section 51.309 SIP does not 

provide the adequate level of visibility 

improvement to meet the BART requirements 

With respect to the relationship of BART and 

requirements for reasonable progress under 40 CFR 

51.308, EPA interprets the reasonable progress 

requirements to apply to BART sources. As 

explained in our guidance, due to the similarity of 

the BART and reasonable progress factors, states 

may reasonably rely on their BART determinations 

to show reasonable progress for those sources for 

the first planning period. However, BART is an 

independent requirement of the statute and the 

RHR. We have disapproved certain BART 

determinations by Wyoming not due to a failure to 

make reasonable progress, but due to a failure to 

consider the BART factors appropriately.’’ 79 FR 

5032, 5098, 5099 (Jan. 30, 2014). 

information before the Agency was 

possibly susceptible to both 

interpretations, our two proposed 

conclusions and courses of action were 

as follows: ‘‘(1) The State’s submittal 

meets the test above and we approve the 

BART Alternative; or (2) the State’s 

submittal falls short of meeting this test 

and we disapprove the BART 

Alternative and promulgate a FIP for 

NOX BART.’’ 

We exercised our rulemaking 

discretion and structured the action 

using the co-proposal approach so that 

our action would enable all interested 

parties to have the opportunity to 

provide meaningful and timely 

comment on either or both approaches. 

In structuring the action in this way, the 

interested public had notice of the 

proposals under consideration and 

whether they had interests at stake. This 

balanced approach was fair in that it 

provided all interested parties with the 

options EPA contemplated in taking 

final action, as well as providing an 

opportunity to comment on the full 

range of potential actions. The 

commenter cites to no CAA provision 

that restricts EPA’s authority to present 

co-proposals. EPA often provides 

alternative approaches for final Agency 

action in our SIP rulemaking proposals, 

as we did here. Additionally, even 

assuming that EPA’s proposed action on 

the Utah regional haze SIPs articulated 

new ‘‘complexity’’ grounds for 

evaluating a regional haze SIP, the 

proposed action provided the public 

with the opportunity to comment. As 

evidenced by the commenter’s 

submission, the commenter had the 

opportunity to provide input on this 

purported new standard to evaluating 

the Utah regional haze SIP and to 

identify any concerns associated with 

the statements at issue. Therefore, even 

if we had created a new complexity 

standard, which we did not, it would 

have been properly proposed and 

applied in this instance. 

As explained above, the EPA proposal 

identified several weaknesses and flaws 

in the State’s SIP submittal in the 

proposed rulemaking,101 and as 

explained in this final action, other 

commenters have made us aware of 

additional weaknesses and uncertainties 

in the SIP submittal.102 Therefore, EPA 

is finalizing our co-proposal to 

disapprove the BART Alternative and 

promulgate a FIP for NOX BART, which 

this commenter recognizes EPA has a 

role and authority to do. 

Furthermore, as explained elsewhere, 

we appreciate and clarify in this final 

action that the State did not intend to 

have its BART Alternative evaluated 

under both the 40 CFR 51.308(e)(2) and 

section 308(e)(3) tests. We, therefore, 

based our final action on our evaluation 

of the State’s submittal under 

§ 51.308(e)(2)’s weight-of-evidence test. 

Finally, regarding the commenter’s 

cross-reference to comments dated 

August 26, 2013, we explained in our 

final action in the Wyoming regional 

haze rulemaking that we disagreed with 

the comments in that context and we 

continue to disagree here.103

D. Compliance With 40 CFR 51.308 

Comment: Two commenters noted 

that EPA’s FIP proposal is unnecessary 

because EPA already found Utah is 

making the required ‘‘reasonable 

progress.’’ The goal of the RH program 

is to make ‘‘reasonable progress’’ 

towards the statute’s national visibility 

goal. Accordingly, EPA promulgated 

regulations ‘‘to assure . . . reasonable 

progress toward meeting’’ the national 

visibility goal, section 7491(b)(2), and 

mandated that EPA’s regulations 

contain ‘‘such emission limits, 

schedules of compliance and other 

measures as may be necessary’’ to assure 

such progress towards meeting that goal, 

‘‘including’’ a requirement that states 

make BART determinations. Id. As EPA 

has stated, ‘‘BART is one component of 

long term strategies to make reasonable 

progress.’’ Regional Haze Regulations 

and Guidelines, 70 FR 39137. 

Because BART’s purpose is to make 

reasonable progress, EPA adopted 

regulations exempting states from 

making BART determinations if they 

can show that other measures for large 

stationary sources will achieve greater 

reasonable progress. 40 CFR 51.308(e)(2) 

(2012). EPA defended those regulations 

in court by arguing that BART is one of 

a number of ‘‘emission limits, schedules 

of compliance and other measures’’ that 

‘‘must’’ be included in a SIP ‘‘‘as may 

be necessary to make reasonable 

progress toward national visibility 

goals.’ ’’ Ctr. for Energy and Econ. Dev. 

v. EPA, 398 F.3d 653, 659–60 (D.C. Cir. 

2005) (confirming BART is but one 

measure for achieving ‘‘reasonable 

progress’’); Cent. Arizona Water 

Conservation Dist. v. EPA, 990 F.2d 

1531, 1534 (9th Cir. 1993) (same). If an 

alternative can better achieve those 


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43914 Federal Register / Vol. 81, No. 128 / Tuesday, July 5, 2016 / Rules and Regulations 

104 70 FR 44154, 44169 (Aug. 1, 2005) (emphasis 

added). 105 71 FR 60612, 60626 (Oct. 13, 2006). 106 79 FR 5032, 5099 (Jan. 30, 2014) (final partial 

approval/partial disapproval of Wyoming regional 

haze SIP submission). 

107 Id. 

108 77 FR 74355, 74357 (Dec. 14, 2012). 

109 398 F.3d 653 (D.C. Cir. 2005). 

110 291 F.3d 1 (D.C. Cir. 2002). 

goals, EPA has stated that BART would 

not be ‘‘necessary to make reasonable 

progress.’’ Id. The court agreed with 

EPA’s analysis, although it overturned 

EPA on other grounds. Id. As the court 

said, ‘‘the focus of the Clean Air Act was 

to achieve ‘actual progress and 

improvement in visibility,’ 42 U.S.C. 

7492(b), not to anoint BART the 

mandatory vehicle of choice.’’ Id. at 660. 

As EPA recognizes, in some 

circumstances no BART controls may be 

necessary to make reasonable progress. 

It follows that in other circumstances, 

depending on a state’s reasonableprogress goals and expected non-BART 

emission reductions, BART controls of 

varying stringency may be necessary. 

Consistent with this goal, EPA has 

approved Utah’s ‘‘reasonable progress’’ 

determination for its RH SIP in its 

entirety. See ‘‘Approval, Disapproval 

and Promulgation of State 

Implementation Plans; State of Utah; 

Regional Haze Rule Requirements for 

Mandatory Class I Areas Under 40 CFR 

51.309,’’ published at 77 FR 74355, 

74367–68 (Dec. 14, 2012). EPA found 

that ‘‘the State met all reasonable 

progress requirements for the Class I 

areas,’’ including by implication any 

required NOX BART limits. In fact, EPA 

stated that Utah’s 2008 RH SIP, 

including BART controls identified in 

that 2008 RH SIP, would result in ‘‘a 

significant decrease in stationary source 

NOX and SO2 emissions.’’ Id. EPA 

further found that the NOX BART 

controls adopted by Utah for the Hunter 

and Huntington EGUs at issue would 

decrease NOX emissions by ‘‘6,200 tons 

[annually] between 2002 and 2018.’’ Id. 

Therefore, EPA acknowledged that 

Utah’s NOX BART limits and controls 

are all that are required to achieve 

‘‘reasonable progress,’’ and no further 

NOX BART requirements should be 

imposed by EPA through its FIP 

proposal. 

Thus, EPA cannot validly judge a 

state’s BART determination outside of 

its reasonable progress context. Owasso 

Indep. Sch. Dist. No. I–011 v. Falvo, 534 

U.S. 426, 434 (2002) (‘‘the words of a 

statute must be read in their context and 

with a view to their place in the overall 

statutory scheme.’’). 

Response: EPA disagrees with these 

comments. The commenters appear to 

be asserting that, since EPA approved 

Utah’s 2011 SIP submission as meeting 

the reasonable progress requirements of 

40 CFR 51.309 with regard to SO2, no 

further controls are necessary to meet 

the RHR’s requirements for NOX and 

PM. However, this assertion ignores our 

statements in the BART Alternatives 

rulemaking that an EPA determination 

that a backstop trading program satisfies 

a state’s reasonable progress obligations 

for SO2 under 40 CFR 51.309 does not 

satisfy that state’s obligation to address 

NOX and PM requirements under 40 

CFR 51.308(e)(1) or (2). In this 

rulemaking, EPA proposed amendments 

to the stationary source NOX and PM 

provisions within § 51.309 precisely in 

order to ‘‘clarify that if EPA determines 

that the SO2 emission reductions 

milestones and backstop trading 

program in the § 51.309 SIPs makes 

greater reasonable progress than BART 

for SO2, this will not constitute a 

determination that BART for PM or NOX

is satisfied for any sources which would 

otherwise be subject to BART for those 

pollutants.’’ 104 The final rulemaking 

reinforced that a reasonable progress 

determination for SO2 under § 51.309’s 

backstop trading program does not 

satisfy the emission reductions 

requirements for non-SO2 pollutants.105

We also took this position in another 

recent regional haze action, in which we 

found that the state’s approved SO2

alternative under § 51.309 did ‘‘not 

provide the adequate level of visibility 

improvement to meet the [non-SO2] 

BART requirements.’’ 106 We then 

reiterated that ‘‘BART is an independent 

requirement of the statute and the 

RHR.’’ 107 Our statements in both the 

national and regional contexts make it 

clear that a reasonable progress 

determination for an SO2 backstop 

trading program under § 51.309 does not 

relieve a state of its obligation to satisfy 

NOX and PM BART. EPA thus can judge 

a state’s BART determination outside 

the reasonable progress context, as they 

are independent requirements. 

The commenters’ claim that EPA’s 

approval of Utah’s § 51.309 program in 

our December 2012 final action means 

that the State met its reasonable 

progress requirements ‘‘in its entirety’’ 

is thus clearly incorrect. In that action 

we determined that the State met the 

requirements of § 51.309 and therefore 

satisfied its reasonable progress 

obligation with regard to the particular 

pollutants covered in the State’s 

alternative, i.e., SO2. This determination 

has no bearing on the State’s 

independent NOX and PM obligations. 

To comply with the RHR, the state must 

still address any BART obligations for 

pollutants not included in the BART 

alternative analysis and therefore not 

covered by the ‘‘better than BART’’ 

determination. 

EPA similarly disagrees that it 

acknowledged that the NOX controls in 

Utah’s 2011 SIP submission are all that 

are required to achieve reasonable 

progress and that EPA should therefore 

not require further NOX BART 

requirements. As explained earlier, 

EPA’s determination that Utah’s 2011 

submission satisfied reasonable progress 

requirements does not constitute 

implicit evaluation and action on Utah’s 

NOX and PM SIP submittal as meeting 

the BART requirements. Furthermore, 

the commenter overlooks EPA’s explicit 

disapproval of Utah’s NOX and PM 

BART determinations in our December 

2012 partial approval/disapproval.108

EPA’s disapproval of Utah’s NOX and 

PM control determinations necessarily 

precludes finding that these same 

controls are all that are required to 

satisfy the RHR’s requirements. EPA is 

thus required to promulgate a NOX

BART FIP, which we are now doing. 

Commenters also take EPA’s statements 

regarding the quantity of anticipated 

NOX reductions from Utah’s rejected 

BART determination out of context. 

These statements were offered as 

reasons why Utah satisfied the RHR’s 

requirement to address impacts on Class 

I areas in other states by achieving 

previously agreed upon emission 

reductions, which is a separate 

consideration from whether the State 

has satisfied its independent NOX and 

PM BART obligations. 

EPA also disagrees that the statements 

in the cited cases have any bearing on 

this action. In Center for Energy and 

Economic Development v. EPA 

(CEED),109 the issue was whether EPA’s 

BART alternative provisions in § 51.309 

were consistent with CAA section 

169A(b)(2) given that they used a 

methodology for establishing the BART 

benchmark that the D.C. Circuit had 

previously vacated in American Corn 

Growers Ass’n v. EPA.110 As part of its 

challenge to EPA’s BART alternative 

provisions, CEED argued that section 

169A(b)(2) requires all states’ SIPs to 

include BART, meaning EPA could not 

allow BART alternatives in place of 

source-specific BART. EPA argued that 

section 169A(b)(2) allows either BART 

or an alternative to BART submitted 

pursuant to § 51.309 if that alternative 

would achieve greater reasonable 

progress than BART, i.e., if the 

alternative is ‘‘better than BART.’’ The 

statements the commenter cites express 

EPA’s view on the narrow issue of 

whether and when we may allow states 

to substitute an SO2 trading program for 


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Federal Register / Vol. 81, No. 128 / Tuesday, July 5, 2016 / Rules and Regulations 43915 

111 40 CFR 51.308(e)(2)(i)(E). 

112 71 FR 60612, 60621 (Oct. 13, 2006). 113 Id. at 60622. 

114See Memorandum from Lydia Wegman and 

Peter Tsirigotis, 2002 Base Year Emission Inventory 

SIP Planning: 8-hr Ozone, PM2.5, and Regional Haze 

Programs (November 18, 2002). 

115The preamble to the RHR provides for 

inclusion of BART and non-BART sources in a 

BART alternative. 64 FR 35714, 35743 (July 1, 

1999). 

116 40 CFR 51.308(e)(2)(E)(v) (containing 

requirements for a state to demonstrate that a 

trading program prevent any significant, potential 

shifting within the state of production and 

emissions from the sources in the program to 

sources outside the program). 

117 Id. 

118Utah Staff Review Report at 27. 

source-specific BART under § 51.309. 

Because these statements address only 

the relationship between BART and 

BART alternatives for SO2 under 

§ 51.309; they have no bearing on 

whether we believe a state’s submission 

of an SO2 trading program satisfies its 

independent obligation to address NOX

and PM, as these obligations were not at 

issue in this case. 

In our December 14, 2012 action we 

approved Utah’s BART Alternative for 

SO2 under 40 CFR 51.309, finding that 

it achieved greater reasonable progress 

than SO2 BART. As explained earlier, 

this determination has no bearing on 

Utah’s outstanding NOX and PM BART 

obligations. We, therefore, disagree that 

today’s action to address these 

obligations is unnecessary. 

Comment: Several commenters 

asserted that Utah’s BART Alternative 

does not achieve greater reasonable 

progress based on the ‘‘clear weight-ofevidence.’’ Utah’s Regional Haze SIP 

also must be rejected under 40 CFR 

51.308(e)(2)(i)(E) because it does not 

achieve ‘‘greater reasonable progress’’ 

based on the ‘‘clear weight-ofevidence.’’ 111

At the outset, Utah’s proposed 

reliance on the ‘‘clear weight-ofevidence’’ test is improper. In 

promulgating regulations allowing for 

the test, 40 CFR 51.308(e)(2)(i)(E), 

offered the following example of when 

the test might be appropriate: ‘‘(1) The 

alternative program achieves emissions 

reductions that are within the range 

believed achievable from source-bysource BART at affected sources, (2) the 

program imposes a firm cap on 

emissions that represents meaningful 

reductions from current levels and, in 

contrast to BART, would prevent 

emissions growth from new sources, 

and (3) the State is unable to perform a 

sufficiently robust assessment of the 

programs using the two pronged 

visibility test due to technical or data 

limitations.’’ 112 None of those 

conditions are met here. Most 

importantly, Utah’s BART Alternative 

does not drive any meaningful 

reductions from ‘‘current levels’’ and 

does not prevent emissions growth from 

new sources, and Utah is not hindered 

by any technical or data limitations 

preventing a sufficiently robust 

visibility assessment. EPA further noted 

that ‘‘a weight-of-evidence comparison 

may be warranted’’ ‘‘when there is 

confidence that the difference in 

visibility impacts between BART and 

the alternative scenarios are expected to 

be large enough.’’ 113 Here, as EPA 

correctly observed, even Utah’s flawed 

modeling demonstrated the superiority 

of BART using the most relevant 

visibility metric and only minimal 

benefits of the BART Alternative 

compared with BART using other 

metrics. 

Several commenters also raised 

concerns regarding emission shifting 

from the power plants covered by the 

SIP to existing sources that are not 

included in this SIP. They suggested 

that due to the nature of the electrical 

generation market, with the adjustments 

to the overall system to add capacity 

elsewhere to accommodate the Carbon 

power plant shutdown (and perhaps 

also to accommodate the emission limit 

reductions at the Hunter and 

Huntington power plants), those shifts 

in capacity could result in increases in 

emissions at power plants outside the 

BART Alternative. The commenters 

further suggested that if those emission 

increases had been considered in the 

State’s weight-of-evidence analysis, the 

BART Alternative may not provide 

greater reasonable progress than BART 

if the emission reductions assessment 

under the Alternative are not permanent 

and were to shift to other power plants. 

As an example, one of the commenters 

provided an analysis for a Utah power 

plant (not covered by the BART 

Alternative) that based on its proximity 

to the nine Class I areas analyzed under 

the BART Alternative, if emission 

increases were to occur at that plant the 

increases could impact visibility 

impairment at the Class I areas. Other 

commenters expressed concern that the 

lost capacity from the BART Alternative 

sources could shift to new sources, and 

explained that the emissions from new 

sources are not evaluated in the State’s 

weight-of-evidence analysis. One 

commenter suggested that this 

Alternative appears to be more like a 

‘‘trading’’ program and that other 

regulations apply. One commenter 

expressed concern that a non-BART 

source is included in the BART 

Alternative, and further, that not all the 

sources in the State that are part of this 

source category are included. 

Response: We agree in part and 

disagree in part with these comments. 

First, as explained elsewhere, we agree 

with the commenter that the State’s 

analysis for the BART Alternative does 

not show that the Alternative clearly 

achieves greater visibility benefits than 

BART. Second, the four examples cited 

by the commenter from our RHR 

preamble were examples, rather than an 

exclusive list of circumstances under 

which a state may use a weight-ofevidence analysis. Therefore, the State 

was not required to fall into one of these 

categories in order to select the weightof-evidence approach to support its 

BART Alternative. Third, we disagree 

that emission reductions must occur 

from current levels, because, consistent 

with the RHR, the baseline date for 

regional haze SIPs is 2002.114

Next we respond to the commenters’ 

concerns about potential shifting of 

production and emissions from the 

sources in the BART Alternative to 

sources outside the BART Alternative. 

We acknowledge that the State’s BART 

Alternative has the following 

characteristics: (1) It includes all the 

BART sources in the State; (2) it 

accounts for emission reductions from a 

non-BART source; and (3) it includes 

some, but not all, sources in the source 

category within the State. The RHR 

provides that BART alternative 

programs may include non-BART 

sources.115 We disagree with 

commenters that suggested the RHR 

trading requirements apply to the Utah 

BART Alternative.116 The RHR trading 

provisions apply to SIPs that establish a 

cap on total emissions from sources that 

are subject to the BART program, and 

further require the owners and operators 

of the sources to hold allowances to 

purchase, sell, and transfer allowances. 

Utah’s SIP contains rate-based emission 

limits on the sources that are subject to 

the BART Alternative and therefore 

does not include a cap on emissions or 

trading provisions. Therefore, the Utah 

SIP does not contain the elements of a 

trading program as described in the 

RHR, which include provisions to 

prevent significant emission shifting.117

Although the State’s SIP explained 

that the Carbon power plant had already 

closed and electricity generated from 

the Carbon power plant has been 

replaced (and the associated costs 

already have been absorbed by Utah rate 

payers and those in other states served 

by PacifiCorp),118 the SIP submittal 

neither identified what electrical 

generating facilities increased capacity 


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43916 Federal Register / Vol. 81, No. 128 / Tuesday, July 5, 2016 / Rules and Regulations 

119The Application of Rocky Mountain Power for 

Approval of a General Rate Increase, No. 20000– 

446–ER–14, Wyoming Public Service Commission, 

(Jan. 23, 2015) (Findings of Fact, Conclusions of 

Law, Decision and Order Nunc Pro Tunc) 

(Available in docket at https://www.regulations.gov/ 

#!documentDetail;D=EPA-R08-OAR-2015-0463- 

0167). An order from the Idaho Public Commission 

also discussed the impacts from Carbon’s retirement 

on the transmission system and noted that ‘‘[t]he 

Company states that retiring Carbon may pose a 

complication with potential transmission system 

impacts.’’ See The Application of PacifiCorp DBD 

DBA Rocky Mountain Power, Case No. PAC–E–12– 

08, Order No. 32701, at 1, Idaho Public Utilities 

Commission (Dec. 27, 2012) (Available in the 

docket at https://www.regulations.gov/

#!documentDetail;D=EPA-R08-OAR-2015-0463- 

0167). 

120Utah’s BART Alternative has the 

characteristics of an ‘‘open market’’ program where 

some, but not all, sources in a source category are 

covered by the SIP measure. EPA Guidance, 

‘‘Improving Air Quality with Economic Incentive 

Programs,’’ at 48, 96, 112–118, EPA–452/R–01–001 

(Jan. 2001), available at https://www3.epa.gov/ttn/

caaa/t1/memoranda/eipfin.pdf); 77 FR 11928 (Feb. 

28, 2012); 77 FR 46952 (Aug. 7, 2012). 

121Letter from Carl Daly to Bryce Bird, Re. EPA 

Region 8 Comments on Utah’s February 2015 Draft 

Regional Haze SIP Revision, at 1 (May 1, 2015). 

(Available in the docket at https://

www.regulations.gov/#!documentDetail;D=EPAR08-OAR-2015-0463-0160). 

122 Id. 

123Utah Staff Review Report at 17, Exhibit 15. 

Winter months in this context are December, 

January, and February. 

124 81 FR 2004, 2023 (EPA says that based on a 

computational model, ‘‘We propose to find that 

visibility benefits associated with NOX reductions 

are much more likely to occur in the winter months 

because this is when aerosol thermodynamics 

favors nitrate formation’’). 

125 Id. 

126See EPA spreadsheet entitled, Canyonlands 

IMPROVE Monitoring Data for 2013 and 2014 

(Available in the in the docket). 

to accommodate the Carbon shut down, 

nor did it provide an analysis of 

whether the capacity replacement 

resulted in increases in visibility 

impairing pollutants. Furthermore, in 

addition to seeking and receiving 

authorization to recover costs associated 

with retirement of the Carbon plant, the 

Company also received authorization 

from state utility commissions to 

recover additional costs, including 

‘‘installation of equipment necessary to 

ensure voltage stability, along with 

various communications upgrades and 

protection and control equipment.’’ 119

It is unclear whether the activities 

associated with these additional costs 

resulted in capacity and emissions 

shifting and increased visibility 

impairment at the affected Class I areas. 

Therefore, while the record before us 

indicates that capacity has shifted, it is 

unclear how the shift was 

accommodated, and whether there are 

any emission increases and associated 

visibility impairment.120

It is therefore unclear whether the 

shift in capacity as a result of the 

Carbon plant retirement results in 

increased emissions and visibility 

impairment at the affected Class I areas. 

Because the record lacks information on 

these questions, we agree with the 

commenters that there is additional 

uncertainty as to whether the BART 

Alternative is better than BART. 

E. Overarching Comments on BART 

Alternative Demonstration 

Comment: The State of Utah 

commented that EPA should approve 

the option that Utah developed in close 

consultation with EPA and not the 

option that Utah was not even aware 

was being prepared or under 

consideration until it was signed by the 

Regional Administrator. Utah worked 

closely and in good faith with the EPA 

and the FLMs to evaluate and 

implement the appropriate controls for 

improving visibility. Up to the point of 

the current proposal, the EPA has 

indicated to Utah that the alternative to 

BART approach and analysis were 

acceptable. During the RH SIP 

development process, Utah and EPA 

worked as regulatory partners—Utah 

working closely and extensively with 

EPA’s staff to ensure that Utah’s BART 

Alternative was approvable. EPA’s 

concurrence with Utah’s RH SIP 

proposal is also supported by EPA’s 

comments submitted during the state 

rulemaking public comment period on 

the current revision of the Utah’s RH 

SIP. EPA did not point to any 

substantive flaws in Utah’s RH SIP, but 

only requested minor clarifications and 

revisions in its 3-page comment letter. 

Response: While we agree that EPA 

worked in close consultation with Utah 

on the BART Alternative within the 

limitations of what the State and 

PacifiCorp were willing to offer in the 

plan, EPA is not required to approve the 

option developed by Utah. As stated 

elsewhere in this document, EPA’s 

comment letter on the State’s proposed 

SIP explicitly explained the following: 

‘‘[p]lease note that we will only come to 

a final conclusion regarding the regional 

haze program for Utah when we take 

action on the program through our own 

public notice-and-comment 

rulemaking.’’ 121 Our May 1, 2015 letter 

further explained to the State that, ‘‘[i]n 

addition, we wish to inform you that we 

are working towards meeting our legal 

obligations that have resulted from our 

January 2013 partial disapproval action 

for Utah’s May 2011 regional haze 

SIP.’’ 122 EPA’s assistance to states and 

our comment letters are intended to be 

helpful to the improvement of any SIP 

revision that is under development, but 

they do not constitute agency action on 

that SIP revision or constitute any 

assurance of positive action on that 

revision upon submission and review. 

Additionally, the State’s efforts to 

involve the FLMs did not adequately 

meet the requirements for FLM 

consultation in developing plan 

revisions. The State could have satisfied 

the consultation requirements by 

providing more time for FLM review so 

that the FLMs would have received the 

full number of 60 days for their review. 

However, in developing the coproposals, consulting with the FLMs, 

and by taking this final action, EPA has 

considered the FLMs’ concerns. 

Comment: Several commenters 

asserted that both Utah and EPA imply 

that nitrate formation in non-winter 

months is not significant,123 or that NOX

reductions will not meaningfully reduce 

nitrates in non-winter months.124 Both 

are untrue. Based on IMPROVE data, 

light extinction attributable to 

ammonium nitrate in non-winter 

months is roughly 20% of that 

attributable to ammonium sulfate. 

Despite the preferential formation of 

ammonium sulfate year round and 

higher ammonium nitrate formation in 

winter months, it is clear that significant 

levels of ammonium nitrate also form in 

non-winter months, and that these are 

likely to be lowered by reductions in 

NOX emissions. Furthermore, while 

EPA notes that wintertime conditions 

favor nitrate formation (versus nonwinter),125 this is accounted for in 

modeling and cannot be used to 

discount those results. 

Response: We partially agree with the 

comment. While EPA did not suggest 

that nitrate in non-winter months is not 

significant, IMPROVE monitoring data 

do show that nitrate light extinction is 

highest in winter and substantially 

smaller in the other seasons. For 

example, in 2014, the most recent year 

of IMPROVE data available at the 

Canyonlands monitor, nitrate 

contributed an average of 31% of total 

light extinction in December to February 

compared to an average of 5% of total 

light extinction from March to 

November. In 2013, nitrate contributed 

an average of 45% of total light 

extinction in December to February 

compared to an average of 7.5% of total 

light extinction from March to 

November. By contrast, sulfate light 

extinction is relatively constant across 

the four seasons.126

Nonetheless, overall nitrate extinction 

at the affected areas is significant, 

particularly on the 20% worst days. For 

example, at Canyonlands on the 20% 

worst days, nitrate contributed 33% and 

17% of total extinction in 2013 and 


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127Both Utah and EPA CALPUFF modeling 

results can be viewed in or obtained from the EPA 

Region 8 offices by contacting the individual listed 

in the FOR FURTHER INFORMATION CONTACT section of 

this document. 

128Andover Technology Partners, Cost of NOX

BART Controls on Utah EGUs to: EC/R Inc. (May 

13, 2016). Andover Technology Partners is a 

subcontractor to EC/R Incorporated. 

129 77 FR 42834 (July 20, 2012) (proposal); 77 FR 

72512, 72514–15 (Dec. 5, 2012) (final). 

130 77 FR 18069 (Mar. 26, 2012) (proposal); 77 FR 

76871 (Dec. 31, 2012) (final). 

131 79 FR 5032, 5099 (Jan. 30, 2014) (final partial 

approval/partial disapproval of Wyoming regional 

haze SIP submission). 

132See also our response to comments on existing 

controls and the baseline, in which we look at the 

cost and visibility benefits at Hunter and 

Huntington of SCR apart from the LNB/SOFA, to 

Continued 

2014, respectively. Given the focus of 

the reasonable progress provisions of 

the RHR on the 20% worst days, we 

consider the monitoring data for these 

days to be more informative than 

seasonal trends in monitoring data. 

We also agree with the commenter 

that the modeling performed by Utah 

and EPA accounts for the fact that 

wintertime conditions favor nitrate 

formation (versus non-winter). In 

particular, the CALPUFF modeling 

performed by Utah and EPA both show 

that, while there will be some benefits 

from NOX controls outside of the winter 

season, the largest benefits in nitrate 

reductions occur in winter months.127

We have taken the strength of the 

modeling results for winter months into 

consideration; however, contrary to 

suggestions that visibility improvements 

during seasons of peak Class I area 

visitation should carry more weight, we 

have evaluated the visibility impacts 

throughout the entire year, regardless of 

the season and have given the most 

weight to those times when the sources 

in question have the largest impacts. In 

particular, as explained elsewhere in 

this document and our RTC document, 

we have given greater weight to the 98th 

percentile CALPUFF metric, which 

captures these highest impact days. 

F. Cost of Controls 

Comment: Several commenters 

submitted comments regarding the costs 

to install SCR at the Hunter and 

Huntington BART EGUs. PacifiCorp 

submitted a technical report developed 

by its consultant, Sargent & Lundy, 

which criticized numerous aspects of 

EPA’s cost analysis developed by our 

contractor, Andover Technology 

Partners (ATP), including catalyst 

volume, SCR design, project and process 

contingency costs, and others. The 

conservation organizations’ consultant 

reviewed PacifiCorp’s cost analyses 

from 2012 and 2014 and provided 

comments about the validity of 

PacifiCorp’s analyses. The National Park 

Service supported EPA’s cost estimates 

in the proposed rule and indicated the 

estimates show that both the combined 

cost of LNB and SOFA plus SCR (SCR 

+ LNB/SOFA) and the incremental cost 

of adding SCR to LNB/SOFA are costeffective and represent BART. The 

conservation organizations also 

supported EPA’s cost estimates in the 

proposed rule. 

Response: EPA has provided a revised 

cost analysis to support our final 

rulemaking. We again used Andover 

Technology Partners (ATP) for 

conducting the analysis. We have 

carefully reviewed the analysis and 

determined that it appropriately 

estimates the costs to install SCR at 

Hunter and Huntington. Of particular 

note is that in our revised cost analysis, 

EPA has accepted both the catalyst 

volume and SCR design suggested by 

Sargent & Lundy. However, we continue 

to reject process and project 

contingency costs and other costs that 

are double counted, not permissible 

under the CCM, or are otherwise not 

justified. The final Andover report and 

spreadsheet provide further details 

regarding how each of these costs was 

addressed in the revised analysis 

supporting this rulemaking.128 Also, in 

our RTC document, we have addressed 

the specific comments concerning the 

capital costs that Sargent & Lundy 

alleges that Andover incorrectly 

excluded from its analysis, as well as all 

other comments regarding our cost 

estimates. 

We concur with the National Park 

Service’s and conservation 

organizations’ supportive comments 

regarding the cost effectiveness of SNCR 

and SCR. In addition, the revised cost 

effectiveness estimates that we prepared 

to support this final rule, when 

considered along with the other five 

BART factors, continue to support 

selection of SCR + LNB/SOFA as BART. 

The conservation organizations’ 

comments pertain to the costs that 

PacifiCorp submitted to the Utah 

Department of Air Quality, and which 

Utah included in its SIP submittal to 

EPA. However, EPA developed separate 

costs to support our FIP, and has 

updated those costs in support of our 

final action. Our RTC document 

contains additional detail concerning 

our consideration of these comments. 

G. Comparison With Other Regional 

Haze Actions 

Comment: Two commenters agreed 

with the comparisons we provided in 

our proposed rule to other BART 

determinations that EPA used to 

support our proposed FIP. One 

commenter disagreed with the 

comparisons. These comparisons 

included Cholla,129 Hayden,130 and 

Laramie River Station.131 The 

commenter who disagreed asserted that 

different methodologies were involved 

in all three cases and that EPA failed to 

provide comparisons to other actions 

that did not support the FIP. The 

commenter provided additional 

examples from EPA actions in Florida, 

Montana, and Nebraska that they 

asserted do not support EPA’s Utah FIP 

decision. 

Response: We continue to find that 

the Cholla, Hayden and Laramie River 

Station comparisons are among the best 

to use considering the specifics of our 

Utah action. The commenter who 

disagreed with these comparisons did 

not show that it would make a 

significant difference to use precisely 

the same methodology in each of the 

determinations that EPA chose to rely 

on. Furthermore, we disagree that the 

methodology involved in the BART 

analyses necessarily must be precisely 

the same for each BART determination 

in order to use the determinations for 

comparison purposes. For example, a 

state may choose to use a slightly 

different methodology to analyze the 

BART factors and select BART, which is 

acceptable so long as the methodology 

is reasonable and consistent with the 

statute, RHR, and BART Guidelines. For 

details, please see the RTC document. 

We also disagree that the cited BART 

determinations in Montana, Florida, and 

Nebraska are useful comparisons or 

show that our BART determination here 

is unreasonable. First, with respect to 

the Florida action, the cited NOX BART 

determination at FPL’s Manatee Plant 

involved two 800 MW oil and naturalgas fired steam turbines. 77 FR 73369, 

73377 (Dec. 10, 2012) (proposal). As the 

two units were equipped with FGR, 

overfire air systems, staged combustion, 

LNB, and reburn, SCR was the only 

available additional control option 

identified. The total annualized cost of 

SCR at the two units would be $31 

million, from which the state computed 

a dollar-per-deciview cost of $66 

million/dv. Id. at 73377. Using these 

figures, the total (i.e. source wide) 

visibility improvements at the most 

impacted Class I area, Chassahowitzka 

NWA, would be 0.47 dv, which is 

considerably below the source-wide 

visibility improvement for SCR + LNB/ 

SOFA at Hunter and Huntington of 

2.948 dv and 3.848 dv, respectively.132


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show that even if we agreed with this commenter 

that the baseline should reflect the installation of 

LNB/SOFA—which we do not—the selection of 

SCR as BART would still be reasonable. The 

numbers used there also compare favorably with 

Manatee. 

133The same commenter notes that the Wyoming 

and Arizona BART determinations we used for 

comparison purposes are currently under litigation; 

however the commenter fails to note that the 

Montana BART determination they propose for 

comparison was actually litigated and vacated. 

With respect to the pending litigation over the 

Wyoming and Arizona BART determinations, there 

are other BART determinations such as Colorado’s 

Hayden Station that are comparable, support our 

selection of SCR + LNB/SOFA, and are not under 

litigation. 

134 70 FR 39122 (Jul. 6, 2005) (emphasis added). 

135 ‘‘Most important, the simplified chemistry in 

the model tends to magnify the actual visibility 

effects of that source. Because of these features and 

the uncertainties associated with the model, we 

believe it is appropriate to use the 98th percentile— 

a more robust approach that does not give undue 

weight to the extreme tail of the distribution.’’ 70 

FR 39104, 39121 (Jul. 6, 2005). 

136 70 FR 39123 (Jul. 6, 2005). 

137Comparison of Single-Source Air Quality 

Assessment Techniques for Ozone, PM2.5, other 

Criteria Pollutants and AQRVs, ENVIRON, 

September 2012. 

In addition, the Manatee Plant impacted 

only one other Class I area, Everglades 

NP, at nearly twice the distance of 

Chassahowitzka NWA. In comparison, 

Hunter and Huntington significantly 

impact nine Class I areas. Furthermore, 

the Manatee Plant received a permit to 

increase natural gas utilization from 

5,670 MMBtu/hr to 8,650 MMBtu/hr, 

which would displace the use of oil and 

provide additional NOX reductions. All 

of these must be considered when 

examining the state’s conclusion that 

SCR would not be cost-effective for 

these units, which was primarily based 

on the dollar-per-deciview cost of $66 

million/dv and not on the raw costeffectiveness number of $3,776/ton. 

While we are not basing our BART 

determinations on the dollar-perdeciview metric, for purposes of 

comparison to Manatee, the dollar-perdeciview cost for Hunter and 

Huntington would be considerably less 

than at Manatee, about $23.7 million/dv 

and $15.8 million/dv, respectively, at 

the most impacted Class I area, and as 

mentioned earlier Hunter and 

Huntington impact many more Class I 

areas than Manatee. 

With respect to the Montana action, 

EPA stated for PPL Colstrip Units 1 and 

2, ‘‘we estimated the incremental cost 

effectiveness of SCR + SOFA (over 

SNCR + SOFA) to [be] $5,770/ton and 

$5,887/ton, respectively. Given these 

costs, we continue to find that SCR + 

SOFA is not justified by the visibility 

improvement that would be provided.’’ 

77 FR 57864, 57889 (Sept. 18, 2012) 

(emphasis added). The commenter 

omits the emphasized language. The 

visibility improvements for the various 

NOX control options for Colstrip Units 

1 and 2 can be seen in our proposal 

action and in general are much lower 

than those for Hunter and Huntington. 

See 77 FR 23988, 24026–27, 24034–35 

(Apr. 20, 2012). In particular, at Colstrip 

Unit 1, the visibility improvements from 

SCR + SOFA at the five impacted Class 

I areas (which is less than the nine 

impacted by Hunter and Huntington) 

ranged from 0.081 to 0.404 dv. At 

Colstrip Unit 2, the visibility 

improvements from SCR + SOFA at the 

same class I areas ranged from 0.091 dv 

to 0.423 dv. These values are all much 

less than for the Hunter and Huntington 

BART units. In any case, our NOX BART 

determinations for Colstrip Units 1 and 

2 were vacated by the Ninth Circuit 

Court of Appeals. Nat’l Parks Conserv. 

Ass’n v. U.S. EPA, 788 F.3d 1134 (9th 

Cir. 2014).133 Finally, commenter’s 

citation to the Nebraska proposal is fully 

addressed by our response to a similar 

comment on our Wyoming regional haze 

action. 79 FR 5032, 5178 (Jan. 30, 2014). 

Please refer to our RTC document for 

additional discussion of our 

comparisons to other BART 

determinations. 

H. CALPUFF Modeling 

Comment: We received many 

comments related to both EPA’s 

modeling for the FIP and Utah’s 

modeling for the BART Alternative. In 

particular, PacifiCorp and its consultant 

asserted that EPA failed to account for 

the margin of error in the CALPUFF 

model and other material limitations of 

CALPUFF. PacifiCorp also asserted that 

we should have used CALPUFF version 

6.42 in our FIP analysis instead of 

version 5.8.4. We partially respond to 

these comments here. Our full responses 

are contained in our RTC document. 

Response: We do not agree with the 

commenter’s criticism of the use of 

CALPUFF. In promulgating the 2005 

BART Guidelines, we responded to 

comments concerning the limitations 

and appropriateness of using CALPUFF. 

In 2005 we explained that CALPUFF is 

the only EPA-approved model for use in 

estimating single source pollutant 

concentrations resulting from the long 

range transport of primary pollutants. In 

addition, it can also be used for other 

purposes such as visibility assessments 

to account for the chemical 

transformations of SO2 and NOX. As 

explained earlier, simulating the effect 

of precursor pollutant emissions on 

PM2.5 concentrations requires air quality 

modeling that not only addresses 

transport and diffusion, but also 

chemical transformations. CALPUFF 

incorporates algorithms for predicting 

both. At a minimum, CALPUFF can be 

used to estimate the relative impacts of 

BART-eligible sources. We are confident 

that CALPUFF distinguishes, 

comparatively, the relative contributions 

from sources such that the differences in 

source configurations, sizes, emission 

rates, and visibility impacts are wellreflected in the model results.134

EPA also recognized the uncertainty 

in the CALPUFF modeling results when 

EPA made the decision (in the final 

BART Guidelines) to recommend that 

states use the 98th percentile visibility 

impairment rather than the highest daily 

impact value. We made the decision to 

consider the 98th percentile primarily 

because the chemistry modules in the 

CALPUFF model are simplified and 

likely to provide conservative (higher) 

results for peak impacts. Since 

CALPUFF’s simplified chemistry could 

lead to model over predictions, EPA 

recommended the use of the 98th 

percentile to avoid giving undue weight 

to the extreme tail of the distribution.135

Therefore, in recognizing some of the 

limitations of the CALPUFF model, we 

determined that use of the maximum 

modeled impact may be overly 

conservative and recommended the use 

of the 98th percentile value. While 

recognizing the limitations of the 

CALPUFF model in the BART 

Guidelines preamble, EPA concluded 

that, for the specific purposes of the 

RHR’s BART provisions, CALPUFF is 

sufficiently reliable to inform the 

decision making process.136

It is further worth noting that the 

CALPUFF model can both predict 

higher and lower visibility impacts 

compared to a photochemical grid 

model. For example, the 2012 ENVIRON 

report on Comparison of Single-Source 

Air Quality Assessment Techniques for 

Ozone, PM2.5, other criteria pollutants 

and AQRVs found that CALPUFF’s 

predictions of the highest 24-hr nitrate 

and sulfate concentrations were lower 

than those predicted by the CAMx 

photochemical grid model in some areas 

within the modeling domain.137 Thus, 

while there is some uncertainty in the 

absolute visibility impacts and benefits 

due to the model and some of the 

simplifications and assumptions used in 

the BART Guidelines modeling 

approach, the relative level of impact 

has been a reliable assessment of the 

degree of visibility impacts and benefit 

from controls. Any uncertainties in 

meteorological conditions that govern 

the transport and diffusion of pollutants 

are less important in comparing impacts 

between two control scenarios, since the 


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138 80 FR 45340, 45350 (July 29, 2015). 139 Id. 

same effects will be included in both the 

base and the control scenario model 

simulations. 

We also do not agree with the 

commenter’s calculation of a ‘‘margin of 

error’’ for CALPUFF. The notion of a 

calculated ‘‘margin of error’’ is not part 

of any modeling guidance and has no 

legal or regulatory basis or applicability 

here. In addition, the commenter’s 

suggestion that a 2012 report titled 

‘‘Documentation of the Evaluation of 

CALPUFF and Other Long Range 

Transport Models Using Tracer Field 

Experiment Data’’, EPA–454/R–12–003 

(ENVIRON Report) establishes a 

standard ‘‘margin of error’’ for 

CALPUFF is unfounded. The ENVIRON 

Report illustrated how well various 

types of modeling systems are able to 

capture regional transport. It does not 

provide any information about the 

accuracy of any models for predicting 

secondary PM2.5 or visibility, nor does it 

indicate that the quantitative 

performance results provided are a 

presumptive globally applicable 

‘‘margin of error.’’ Rather, these results 

are simply a way to compare various 

modeling systems in terms of 

performance for skill in long range 

transport. Thus, we do not agree that the 

ENVIRON Report provides a 

presumptive margin of error that can be 

applied to the modeling results in 

Utah’s SIP or EPA’s FIP. 

With regard to Utah’s use of 

CALPUFF in its SIP revision 

specifically, we note that the State was 

not required to use CALPUFF for 

purposes of its BART Alternative 

Demonstration under 40 CFR 

51.308(e)(2)(i). Utah or PacifiCorp could 

have used other EPA-approved models 

with more advanced chemistry and 

dispersion techniques to support the 

BART Alternative demonstration but 

chose not to do so. 

With regard to our use of CALPUFF 

for purposes of the FIP modeling, as 

explained in more detail in our RTC 

document, the legal deadline for 

challenging EPA’s recommendation to 

use CALPUFF in BART analyses has 

passed. Furthermore, although the EPA 

proposed revisions to 40 CFR part 51, 

appendix W, Guideline on Air Quality 

Models (‘‘Guideline’’) in 2015, these 

proposed changes to the Guideline do 

not affect our recommendation in the 

2005 BART Guidelines to use CALPUFF 

in the BART determination process.138

Rather, as explained in the preamble to 

the proposed Guideline revisions, we 

consider it appropriate to continue 

using CALPUFF for BART 

determinations, given that the vast 

majority of BART determinations have 

been made using CALPUFF.139

In particular, for our FIP modeling, 

we used the current EPA-approved 

version of CALPUFF (Version 5.8.4, 

Level 130731). We disagree with the 

commenters that a new CALPUFF 

version should be used for the BART 

determinations. We relied on version 

5.8 of CALPUFF because it is the 

version approved by EPA through a 

public notice-and-comment rulemaking, 

in accordance with the Guidelines (40 

CFR part 51, appendix W, section 

6.2.1.e). Later versions of CALPUFF are 

not approved by EPA for regulatory 

purposes, and we do not agree that the 

changes made to this most recent 

version of CALPUFF were simple model 

updates to address bugs. A full 

evaluation of a new model such as 

CALPUFF version 6.4 is needed before 

it should be used for regulatory 

purposes as errors that are not 

immediately apparent can be introduced 

along with new model features. 

In response to comments, EPA 

performed additional modeling analysis 

to assess the combined benefit of SCR 

when applied to each of the two BART 

units at the Hunter facility. We did the 

same for the Huntington facility. These 

modeling results are shown in Tables 6 

and 7 earlier in this document. 

Otherwise, we did not receive any 

comments that convinced us to alter our 

CALPUFF modeling analysis, and the 

comments we received do not justify a 

change in our BART determinations or 

our evaluation of the State’s BART 

Alternative. We discuss these and other 

modeling comments in detail in our 

RTC document. 

I. Consideration of Existing Controls 

Comment: Several commenters 

asserted that EPA did not properly take 

into account the existing pollution 

control technology in use at the Hunter 

and Huntington BART units, as required 

by CAA section 169A(g)(2) and the 

BART Guidelines. Two of these 

commenters alleged that EPA was 

required to consider updated 

combustion controls, which were 

installed to comply with Utah’s regional 

haze SIP. The commenters said EPA 

improperly used 2001–2003 emissions 

data to establish the baseline emissions 

for the Utah BART Units and that this 

is neither realistic nor provides the 

anticipated emissions as required by the 

BART Guidelines. The commenters 

asserted that had EPA relied on more 

recent emissions data, which reflect the 

NOX reductions achieved by some of 

these newly installed controls, the costeffectiveness values for SCR would have 

been higher, while the visibility 

improvement associated with SCR 

would have been lower. 

Commenters pointed to an 8th Circuit 

court decision on EPA’s final action on 

the North Dakota regional haze SIP 

where the Court found that EPA had 

failed to properly consider the existing 

pollution control technology at the Coal 

Creek Station. Commenters also asserted 

that in other EPA regional haze actions, 

EPA had adjusted baseline emissions to 

account for recently installed controls, 

such as EPA’s final actions on the 

Arizona and Colorado regional haze 

SIPs, and settlement agreement with 

EPA Region 8 for the Deseret Bonanza 

plant. This commenter argued that 

because EPA had adjusted baseline 

emissions for some Arizona and 

Colorado EGUs to account for controls 

recently installed to satisfy consent 

decrees obligations or CAA 

requirements unrelated to regional haze, 

EPA was required to do so for Utah’s 

EGUs as well. 

Two final commenters submitted 

supportive comments regarding the 

need for using a standard baseline 

period to provide for greater national 

consistency. One of these commenters 

noted examples where EPA has 

evaluated NOX BART based on a 

baseline period from before the 

installation of the pollution controls, for 

the Navajo regional haze plan and the 

Wyoming regional haze plan. 

Response: We disagree with 

comments that EPA failed to consider or 

unreasonably considered the existing 

pollution control technology at the 

Hunter and Huntington BART units. 

One of the statutory factors EPA is to 

consider for BART is ‘‘any existing 

pollution control technology in use at 

the source.’’ 42 U.S.C. 7491(g)(2). The 

CAA and the BART Guidelines do not 

specify how states or EPA must ‘‘take 

into consideration’’ this factor. Nor did 

the Eighth Circuit Court of Appeals 

specify how existing controls must be 

taken into account; instead it only 

examined the meaning of the word 

‘‘any,’’ holding that EPA misinterpreted 

the term. North Dakota v. U.S. EPA, 730 

F.3d 750, 762–64 (8th Cir. 2013). The 

Court did not examine the meaning of 

the phrase ‘‘take into consideration.’’ 

See id. As the statute is silent on how 

to take into consideration existing 

controls, under Chevron U.S.A. v. 

NRDC, 467 U.S. 837, 843–44 (1984), this 

silence creates a gap for EPA to fill. As 

next summarized and detailed in our 

RTC document, we are reasonably 

considering existing controls in several 

ways. 


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140See Western Regional Air Partnership 

Regional Haze Rule Reasonable Progress Summary 

Report, Air Resource Specialist, Inc., State and 

Class I Area Summaries, Appendix p. 6–29, Table 

6.13–19 (June 28, 2013). Available in the docket and 

at http://www.wrapair2.org/RHRPR.aspx. 

141 77 FR 9450 (Feb. 16, 2012) (codified at 40 CFR 

60.42Da). 

First, the BART Guidelines state that 

existing pollution control technology in 

use at the source affects the availability 

of control options and their impacts. 40 

CFR part 51, appendix Y, at IV.A. The 

Guidelines go on to explain that ‘‘[f]or 

emission units subject to a BART 

review, there will often be control 

measures or devices already in place. 

For such emission units, it is important 

to include control options that involve 

improvements to existing controls and 

not to limit the control options only to 

those measures that involve a complete 

replacement of control devices.’’ 40 CFR 

part 51, appendix Y, at IV.D.1.6. We 

have followed this recommendation. We 

find that the existing combustion 

controls, LNB/SOFA, cannot be 

reasonably upgraded, and we are not 

considering a control option that 

involves their complete replacement. 

The post-combustion control options, 

SNCR and SCR, by their nature can 

operate independently of combustion 

controls and without changes to the 

combustion controls, another way in 

which we considered the existing 

controls when evaluating SNCR and 

SCR. 

Consistent with the Guidelines’ 

statement that existing pollution control 

equipment in use at the source affects 

the impacts of the control options, we 

used the sources’ current NOX emission 

rates when we evaluated the size, 

design, and reagent/catalyst cost of 

SNCR and SCR. For example, in the case 

of Hunter Unit 1, we did not use the 

baseline emission rate of 0.40 lb/

MMBtu, but rather the current emission 

rate of 0.21 lb/MMBtu that 

appropriately reflects the installation of 

LNB/SOFA. Due to the lower NOX

emission rate, the size of the SNCR and 

SCR systems and the amount of reagent/ 

catalyst necessary to operate them are 

lower than if we had simply assumed 

the baseline emission rate. This is a 

reasonable way in which to consider 

existing pollution control technology. 

As discussed in our Wyoming action 

and in additional detail in our RTC 

document for this action, baseline 

emissions should be ‘‘a realistic 

depiction of anticipated annual 

emissions’’ before the installation of 

BART. 40 CFR part 51, appendix Y, at 

IV.D.4.d. Because the LNB/OFA were 

installed pursuant to Utah’s proposed 

BART determination, we used the 

period 2001–2003, prior to the 

installation of LNB/OFA at the Hunter 

and Huntington BART units, for 

baseline emissions, which in turn we 

used to evaluate the cost-effectiveness 

and visibility of control options. As a 

result, the existing LNB/OFA were not 

included in the baseline. According to 

the commenter, this skewed EPA’s 

analysis. 

We disagree. Because we have also 

considered the existing controls in our 

final BART determination by examining 

the cost-effectiveness and visibility 

benefit of SNCR and SCR relative to the 

existing LNB/SOFA as well as in 

tandem with LNB/SOFA, we have 

avoided any possibility that exclusion of 

the LNB/OFA from the baseline could 

result in an unreasonable BART 

selection. The cost-effectiveness values 

of SCR and SNCR relative to the existing 

LNB/SOFA are presented in the per-unit 

tables for Hunter and Huntington 

(Tables 2–5) under ‘‘Incremental costeffectiveness.’’ In other words, the costeffectiveness value for SCR alone 

(assuming the existing LNB/SOFA) is 

essentially the same as the incremental 

cost-effectiveness of SCR + LNB/SOFA 

as compared to LNB/SOFA that is 

presented in the tables. As can be seen, 

the incremental cost-effectiveness 

values of SCR + LNB/SOFA relative to 

LNB/SOFA are, for all four units, 

somewhat lower than the incremental 

cost-effectiveness of SCR relative to 

SNCR. As explained in the section 

giving the rationale for our final action, 

we find the incremental costeffectiveness of SCR to be reasonable 

relative to SNCR; therefore it is also 

reasonable relative to the existing LNB/ 

SOFA. 

Another way to make the same point 

is to, for the sake of argument, accept 

(which we do not) commenter’s position 

that the baseline should reflect the LNB/ 

SOFA. In that case, the values in the 

tables for the incremental costeffectiveness of SCR + LNB/SOFA 

relative to LNB/SOFA can serve as a 

proxy for the average cost-effectiveness 

of SCR (assuming LNB/SOFA in the 

baseline). As shown by our 

comparisons, the incremental costeffectiveness of SCR + LNB/SOFA is 

generally reasonable given the visibility 

benefits. This in turn shows that, even 

accepting for the sake of argument that 

LNB/SOFA should be reflected in the 

baseline, the average cost-effectiveness 

of SCR remains reasonable. Similar 

considerations apply to the incremental 

visibility benefits of SCR + LNB/SOFA 

relative to LNB/SOFA, which can be 

used as a proxy for the visibility benefits 

of SCR alone assuming that LNB/SOFA 

are reflected in the baseline. As shown 

by our comparisons, the incremental 

visibility benefits of SCR + LNB/SOFA 

relative to SNCR + LNB/SOFA are 

substantial and justify the costs of SCR. 

Since the incremental visibility benefits 

of SCR + LNB/SOFA relative to LNB/

SOFA are necessarily larger than the 

incremental benefits relative to SNCR + 

LNB/SOFA, the incremental visibility 

benefits of SCR + LNB/SOFA relative to 

LNB/SOFA will also justify the costs of 

SCR. This in turn shows that even if we 

accepted the commenter’s position— 

which we do not—the visibility benefits 

of SCR would justify its selection. For 

our detailed responses, please see our 

RTC document. 

Finally, we acknowledge the 

supportive comments from two 

commenters on this issue and agree 

with many of the points that were made, 

for reasons explained elsewhere in this 

document and in our RTC document. 

J. PM10 BART 

Comment: We received several minor 

comments on Utah’s PM10 BART 

determinations. One commenter in 

particular asserted that Utah 

underestimated the control effectiveness 

of baghouses, which should be able to 

achieve a limit of 0.010 lb/MMBtu or 

even lower. 

Response: EPA agrees that baghouses 

have very high PM control efficiency 

capabilities. However, due to the low 

contribution of direct PM emissions 

from point sources such as Hunter Units 

1 and 2 and Huntington Units 1 and 

2 140 to visibility impairment and, 

consequently, the low anticipated 

visibility benefits from small PM 

reductions, lowering the emission limit 

to 0.010 is unlikely to result in any 

meaningful visibility improvement. We 

agree with Utah that the existing PM10

emission limit adopted for these sources 

in Section IX, Part H.22 of Utah’s SIP 

satisfies BART for these units. We are 

finalizing our approval of Utah’s PM10

BART determination at Hunter Units 1 

and 2 and Huntington Units 1 and 2. We 

find that an emission limit of 0.015 lb/ 

MMBtu represents what can be 

continuously achieved with a properly 

operated baghouse on these units. The 

fabric filters (i.e., baghouses) at Hunter 

and Huntington are all new since they 

were installed after 2008. Recent PSD 

BACT limits for coal-fired EGUs with 

new baghouses have typically ranged 

from 0.01 to 0.015 lb/MMBtu using 

Method 5. 

In addition, we note that the latest 

revision to the EGU New Source 

Performance Standards (NSPS) requires 

modified units to meet a PM limit of 

0.015 lb/MMBtu.141 Also, the EGU 

MATS rule set a PM emissions standard 


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142 40 CFR part 51, appendix Y, section IV.C. 

While the Supreme Court reversed the D.C. Circuit’s 

judgment on the MATS rule, the Supreme Court did 

so based on EPA’s approach to the ‘‘appropriate and 

necessary’’ finding, not EPA’s determination of 

MACT for EGUs. Michigan v. EPA, 135 S. Ct. 2699 

(2015). 

143As necessary for our approval, we are filling 

gaps in the 2015 Utah regional haze RH SIP 

submittals with the following already-approved 

sections from the 2011 Utah RH SIP: Section 

XX.B.8, Figures 1 and 2, Affected Class I Areas, pp. 

8–9; Section XX.D.6.b, Table 3, BART-Eligible 

Sources in Utah, p. 21; Section. XX.D.6.c, Sources 

Subject to BART, pp. 21–23. 

of 0.03 lb/MMBtu as MACT for existing 

EGUs, and the BART Guidelines 

provide that, ‘‘unless there are new 

technologies subsequent to the MACT 

standards which would lead to costeffective increases in the level of 

control, you may rely on the MACT 

standards for purposes of BART.’’ 142

Therefore, we are finalizing our 

proposed approval of Utah’s BART 

determination for PM10 at Hunter Units 

1 and 2 and Huntington Units 1 and 2. 

K. Environmental Justice 

Comment: One commenter requested 

that EPA’s FIP address any 

disproportionately high and adverse 

human health, economic, and 

environmental impacts on minority and 

low-income communities in Utah due to 

the regional haze plan. The commenter 

noted that this may be accomplished 

consistent with federal Executive Order 

12898, which establishes environmental 

justice policy. The commenter also 

noted that societal costs such as general 

public health costs associated with poor 

air quality should be considered in the 

environmental justice analysis. 

Response: In making a final 

determination in this case, EPA 

considered Executive Order 12898, 

which establishes federal executive 

policy on environmental justice. This 

Executive Order directs federal 

agencies, to the greatest extent 

practicable and permitted by law, to 

make environmental justice part of their 

mission by identifying and addressing, 

as appropriate, disproportionately high 

and adverse human health or 

environmental effects of their programs, 

policies, and activities on minority 

populations and low-income 

populations in the United States. EPA 

has determined that this final rule will 

not have disproportionately high and 

adverse human health or environmental 

effects on minority or low-income 

populations. The installation of SCR at 

the two facilities will ensure greater 

emissions reductions of NOX resulting 

in overall increases in the level of 

environmental protection for all affected 

populations. 

EPA disagrees with the comment that 

societal costs such as general public 

health costs associated with poor air 

quality should be considered in the 

environmental justice analysis for this 

action. As addressed elsewhere in our 

RTC document, neither section 169A of 

the CAA, nor the BART Guidelines, 

require the BART analysis to include or 

quantify benefits to health, as health 

impacts are appropriately addressed 

under other CAA programs. Moreover, 

an analysis of societal costs is unlikely 

to alter the impact relating to 

environmental justice concerns because 

the final rule will result in greater 

protection for all affected populations as 

a result of the installation of the most 

stringent control technology available 

for NOX. 

III. Final Action 

For the reasons discussed more fully 

in sections I and II and detailed in our 

proposal and its accompanying 

supporting materials, in this action, we 

are partially approving and partially 

disapproving revisions to the Utah SIP 

submitted by the State of Utah on June 

4, 2015. We are taking no action on the 

Utah SIP submittal of October 20, 2015. 

Section 110(k)(3) of the Act addresses 

the situation in which an entire 

submittal, or a separable portion of a 

submittal, meets all applicable 

requirements of the Act. In the case 

where a separable portion of the 

submittal meets all the applicable 

requirements, partial approval may be 

used to approve that part of the 

submittal and disapprove the 

remainder. Since the portions of the 

regional haze SIP submittal we are 

approving are separable from the 

portions we are disapproving as 

explained earlier, each approved PM10

BART determination for a particular 

pollutant for a given source will have an 

enforceable date of five years from the 

date of EPA’s approval. 

Under section 110(k)(4) of the Act, 

EPA may approve a submittal based on 

a commitment of the State to adopt 

specific enforceable measures no later 

than one year after the date of approval 

of the submittal. We are conditionally 

approving the State’s recordkeeping 

requirements for the PM BART emission 

limitations based on Utah’s commitment 

to adopt and submit certain measures to 

address the deficiencies in the 

recordkeeping requirements. If the State 

fails to adopt and submit these measures 

within one year of this action, our 

conditional approval will be treated as 

a disapproval. 

Under section 110(c)(1)(B) of the Act, 

within two years of disapproving a 

required submittal in whole or in part, 

EPA must promulgate a FIP to address 

the deficiencies, unless the State 

corrects the deficiencies through a 

submittal and EPA approves the 

submittal before we promulgate a FIP. 

As a result of our prior disapproval of 

Utah’s PM and NOX BART submittals in 

2012, there was a pending obligation for 

EPA to promulgate a FIP for PM and 

NOX BART. In this action, we are 

promulgating a FIP for NOX BART. 

Because we are approving Utah’s 

revised PM BART submittal, which 

corrects the previous deficiencies in the 

original PM BART submittal, there is no 

longer an obligation for EPA to 

promulgate a FIP for PM BART. Thus, 

EPA has discharged its FIP obligations 

with respect to PM and NOX BART for 

the State of Utah. 

A. Final Partial Approval 

1. We are approving these elements of 

the State’s SIP submittals, which rely on 

elements from prior approvals: 143

• BART determinations and emission 

limits for PM10 at Hunter Units 1 and 2 

and Huntington Units 1 and 2. 

• Monitoring, recordkeeping, and 

reporting requirements for units subject 

to the PM10 emission limits, including 

conditional approval of the 

recordkeeping requirements for the 

PM10 emission limits. 

B. Final Partial Disapproval and Federal 

Implementation Plan 

1. We are disapproving these aspects 

of the State’s June 4, 2015 SIP submittal: 

• NOX BART Alternative that 

includes NOX, and SO2 emission 

reductions from Hunter Units 1 through 

3, Huntington 1 and 2, and Carbon Units 

1 and 2, and PM10 emission reductions 

from Carbon Units 1 and 2. 

• Monitoring, recordkeeping and 

reporting requirements for units subject 

to the BART Alternative. 

2. We are promulgating a FIP to 

address the deficiencies in the Utah 

regional haze SIP. The FIP includes the 

following elements: 

• NOX BART determinations and 

limits for Hunter Units 1 and 2, 

Huntington Units 1 and 2. 

• Monitoring, recordkeeping, and 

reporting requirements applicable to 

Hunter Units 1 and 2, and Huntington 

Units 1 and 2. 

C. No Action 

1. We are taking no action on the 

State’s October 20, 2015 SIP submittal 

which includes the following: 

• The enforceable commitments to 

revise, at a minimum, SIP Section 

XX.D.3.c and State rule R307–150 by 

March 2018. 


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144 44 U.S.C. 3501 et seq. 

145Andover Technology Partners, Cost of NOX

BART Controls on Utah EGUs, to EC/R, Inc. (May 

13, 2016). Andover Technology Partners is a 

subcontractor to EC/R Incorporated. 

IV. Incorporation by Reference 

In this rule, the EPA is finalizing 

regulatory text that includes 

incorporation by reference. In 

accordance with requirements of 1 CFR 

51.5, the EPA is finalizing the 

incorporation by reference of the Utah 

Administrative Code discussed in 

section III, Final Action of this 

preamble. The EPA has made, and will 

continue to make, these documents 

generally available electronically 

through www.regulations.gov and/or in 

hard copy at the appropriate EPA office 

(see the ADDRESSES section of this 

preamble for more information). 

V. Statutory and Executive Order 

Reviews 

A. Executive Order 12866: Regulatory 

Planning and Review and Executive 

Order 13563: Improving Regulation and 

Regulatory Review 

This action is exempt from review by 

the Office of Management and Budget 

(OMB) because this final rule applies to 

only two facilities containing four BART 

units. It is therefore not a rule of general 

applicability. 

B. Paperwork Reduction Act 

This action does not impose an 

information collection burden under the 

provisions of the Paperwork Reduction 

Act (PRA).144 Because this final rule 

applies to just two facilities, the PRA 

does not apply. 

C. Regulatory Flexibility Act 

I certify that this action will not have 

a significant economic impact on a 

substantial number of small entities 

under the RFA. This action will not 

impose any requirements on small 

entities. 

EPA is partially disapproving the 

State’s SIP submittal and promulgating 

a FIP that consists of imposing federal 

controls to meet the BART requirement 

for emissions on four specific BART 

units at two facilities in Utah. The net 

result of this action is that EPA is 

requiring direct emission controls on 

selected units at only two sources, and 

those sources are large electric 

generating plants that are not owned by 

small entities, and therefore the owners 

are not a small entities under the RFA. 

D. Unfunded Mandates Reform Act 

(UMRA) 

This action does not contain an 

unfunded mandate of $100 million or 

more as described in UMRA, 2 U.S.C. 

1531–1538, and does not significantly or 

uniquely affect small governments. 

EPA has determined that Title II of 

the UMRA does not apply to this rule. 

In 2 U.S.C. 1502(1) all terms in Title II 

of UMRA have the meanings set forth in 

2 U.S.C. 658, which further provides 

that the terms ‘‘regulation’’ and ‘‘rule’’ 

have the meanings set forth in 5 U.S.C. 

601(2). Under 5 U.S.C. 601(2), ‘‘the term 

‘rule’ does not include a rule of 

particular applicability relating to . . . 

facilities.’’ Because this rule is a rule of 

particular applicability relating to all 

four BART units at the Hunter and 

Huntington plants, EPA has determined 

that it is not a ‘‘rule’’ for the purposes 

of Title II of the UMRA. The private 

sector expenditures that result from 

promulgating a FIP include BART 

controls for all four units at the Hunter 

and Huntington plants are $58.6 

million 145 per year. Additionally, we do 

not foresee significant costs (if any) for 

state and local governments. Thus, 

because the annual expenditures 

associated with promulgating a FIP are 

less than the threshold of $100 million 

in any one year, this final rule is not 

subject to the requirements of sections 

202 or 205 of UMRA. This final rule is 

also not subject to the requirements of 

section 203 of UMRA because it 

contains no regulatory requirements that 

might significantly or uniquely affect 

small governments. 

E. Executive Order 13132: Federalism 

This action does not have federalism 

implications. It will not have substantial 

direct effects on the states, on the 

relationship between the national 

government and the states, or on the 

distribution of power and 

responsibilities among the various 

levels of government. 

F. Executive Order 13175: Consultation 

and Coordination With Indian Tribal 

Governments 

This action does not have tribal 

implications as specified in Executive 

Order 13175. It will not have substantial 

direct effects on tribal governments. 

Thus, Executive Order 13175 does not 

apply to this action. 

G. Executive Order 13045: Protection of 

Children From Environmental Health 

Risks and Safety Risks 

The EPA interprets Executive Order 

13045 as applying only to those 

regulatory actions that concern 

environmental health or safety risks that 

the EPA has reason to believe may 

disproportionately affect children, per 

the definition of ‘‘covered regulatory 

action’’ in section 2–202 of the 

Executive Order. This action is not 

subject to Executive Order 13045 

because the EPA does not believe the 

environmental health or safety risks 

addressed by this action present a 

disproportionate risk to children. 

Moreover, ‘‘regulation’’ or ‘‘rule,’’ is 

defined in Executive Order 12866 as ‘‘an 

agency statement of general 

applicability and future effect.’’ E.O. 

12866 does not define ‘‘statement of 

general applicability,’’ but this term 

commonly refers to statements that 

apply to groups or classes, as opposed 

to statements, which apply only to 

named entities. The FIP therefore is not 

a rule of general applicability because 

its requirements apply and are tailored 

to only the Hunter and Huntington 

plants, which are individually 

identified facilities. Thus, it is not a 

‘‘rule’’ or ‘‘regulation’’ within the 

meaning of E.O. 12866. However, as this 

action will limit emissions of NOX, it 

will have a beneficial effect on 

children’s health by reducing air 

pollution. 

H. Executive Order 13211: Actions 

Concerning Regulations That 

Significantly Affect Energy Supply, 

Distribution, or Use 

This action is not subject to Executive 

Order 13211, because it is not a 

significant regulatory action under 

Executive Order 12866. 

I. National Technology Transfer and 

Advancement Act 

This rulemaking does not involve 

technical standards. 

J. Executive Order 12898: Federal 

Actions To Address Environmental 

Justice in Minority Populations and 

Low-Income Populations 

The EPA believes that this action does 

not have disproportionately high and 

adverse human health or environmental 

effects on minority populations, lowincome populations and/or indigenous 

peoples, as specified in Executive Order 

12898 (59 FR 7629, February 16, 1994). 

The documentation for this decision 

is contained within the docket in a 

document entitled ‘‘Environmental 

Justice Analysis, November 2015.’’ This 

final rule will result in overall emission 

reductions for NOX, and PM10 and 

therefore an increase in the level of 

environmental protection for all affected 

populations. 

K. Congressional Review Act 

This action is not subject to the CRA 

because this is a rule of particular 

applicability. Additionally, this action 


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Federal Register / Vol. 81, No. 128 / Tuesday, July 5, 2016 / Rules and Regulations 43923 

is not a ‘‘major rule’’ as defined by 5 

U.S.C. 804(2). 

L. Judicial Review 

Under section 307(b)(1) of the CAA, 

petitions for judicial review of this 

action must be filed in the United States 

Court of Appeals for the appropriate 

circuit by September 6, 2016. Pursuant 

to CAA section 307(d)(1)(B), this action 

is subject to the requirements of CAA 

section 307(d) as it promulgates a FIP 

under CAA section 110(c). Filing a 

petition for reconsideration by the 

Administrator of this final rule does not 

affect the finality of this action for the 

purposes of judicial review nor does it 

extend the time within which a petition 

for judicial review may be filed, and 

shall not postpone the effectiveness of 

such rule or action. This action may not 

be challenged later in proceedings to 

enforce its requirements. See CAA 

section 307(b)(2). 

Authority: 42 U.S.C. 7401 et seq. 

List of Subjects in 40 CFR Part 52 

Environmental protection, Air 

pollution control, Incorporation by 

reference, Intergovernmental relations, 

Nitrogen dioxide, Particulate matter, 

Sulfur oxides. 

Dated: June 1, 2016. 

Gina McCarthy, 

Administrator. 

40 CFR part 52 is amended as follows: 

PART 52—APPROVAL AND 

PROMULGATION OF 

IMPLEMENTATION PLANS 

■ 1. The authority citation for part 52 

continues to read as follows: 

Authority: 42 U.S.C. 7401 et seq. 

Subpart TT—Utah 

■ 2. Section 52.2320 is amended by: 

■ a. In the table in paragraph (c), under 

the heading ‘‘R307–110. General 

Requirements: State Implementation 

Plan’’ revising the entry ‘‘R307–110– 

17.’’ 

■ b. In the table in paragraph (e), under 

the heading ‘‘XVII. Visibility 

Protection’’ adding in numerical order 

the entry ‘‘Section XX.D.6. Best 

Available Retrofit Technology (BART) 

Assessment for NOX and PM’’. 

The revision and addition read as 

follows: 

§ 52.2320 Identification of plan. 

* * * * * 

(c) * * * 

Rule No. Rule title State effective 

date 

Final rule citation, 

date Comments 

*******

R307–110. General Requirements: State Implementation Plan 

*******

R307–110– 

17.

Section IX. Control Measures for Area and 

Point Sources, Part H, Emissions Limits.

6/4/2015 [Insert Federal Register citation] 7/5/

2016.

Except for Section IX.H.21.e. which is conditionally approved through one year 

from [Insert date of publication in the 

Federal Register], IX.H.21.g., Sections 

of IX.H.21 that reference and apply to 

the source specific emission limitations 

disapproved in Section IX.H.22, and 

Sections IX.H.22.a.ii-iii, IX.H.22.b.ii, and 

IX.H.22.c. 

*******

* * * * * (e) * * * 

Rule title State effective 

date Final rule citation, date Comments 

*******

XVII. Visibility Protection 


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Rule title State effective 

date Final rule citation, date Comments 

*******

Section XX.D.6. Best Available Retrofit Technology (BART) Assessment for NOX and PM.6/4/2015 [Insert Federal Register 

citation] 7/5/2016.

Except for XX.D.6.a the phrase ‘‘and BART for 

NOX through alternative measures under 40 

CFR 51.308(e)(2)’’; XX.D.6.c; XX.D.6.d the 

phrase ‘‘NOX and’’ in the first sentence, the 

entire last sentence in the introductory paragraph, all SO2 and NOX provisions and the 

word ‘‘Permitted’’ in the ‘‘Utah Permitted Limits’’ column in Table 5, ‘‘Hunter 3’’ and the 

Hunter limits, and all provisions in the ‘‘Presumptive BART Rates’’ column in Table 5; 

XX.D.6.e the phrase ‘‘, and pursuant to 

51.308(e)(2)(E)(3) all alternative measures 

must take place within the first planning period’’, the rows beginning with ‘‘Hunter 3’’, 

‘‘Carbon 1’’ and ‘‘Carbon 2’’ in Table 6, and 

the entire paragraph immediately following 

Table 6. 

*******

■ 3. Section 52.2336 is added to read as 

follows: 

§ 52.2336 Federal implementation plan for 

regional haze. 

(a) Applicability. (1) This section 

applies to each owner and operator of 

the following emissions units in the 

State of Utah: 

(i) PacifiCorp Hunter Plant Units 1 

and 2; and 

(ii) PacifiCorp Huntington Plant Units 

1 and 2. 

(2) [Reserved] 

(b) Definitions. Terms not defined in 

this paragraph (b) shall have the 

meaning given them in the Clean Air 

Act or EPA’s regulations implementing 

the Clean Air Act. For purposes of this 

section: 

(1) BART means Best Available 

Retrofit Technology. 

(2) BART unit means any unit subject 

to a Regional Haze emission limit in 

Table 1 of this section. 

(3) Continuous emission monitoring 

system or CEMS means the equipment 

required by this section to sample, 

analyze, measure, and provide, by 

means of readings recorded at least once 

every 15 minutes (using an automated 

data acquisition and handling system 

(DAHS)), a permanent record of NOX

emissions, diluent, or stack gas 

volumetric flow rate. 

(4) FIP means Federal Implementation 

Plan. 

(5) The term lb/MMBtu means pounds 

per million British thermal units of heat 

input to the fuel-burning unit. 

(6) NOX means nitrogen oxides. 

(7) Operating day means a 24-hour 

period between 12 midnight and the 

following midnight during which any 

fuel is combusted at any time in the 

BART unit. It is not necessary for fuel 

to be combusted for the entire 24-hour 

period. 

(8) The owner/operator means any 

person who owns or who operates, 

controls, or supervises a unit identified 

in paragraph (a) of this section. 

(9) Unit means any of the units 

identified in paragraph (a) of this 

section. 

(c) Emission limitations. (1) The 

owners/operators of emission units 

subject to this section shall not emit, or 

cause to be emitted, NOX in excess of 

the following limitations: 

TABLE 1 TO § 52.2336—EMISSION

LIMITATIONS FOR BART UNITS

Source name/BART unit 

NOX Emission 

limitation—lb/

MMBtu 

(30-day rolling 

average) 

PacifiCorp Hunter Plant/Unit 

1 1 ...................................... 0.07 

PacifiCorp Hunter Plant/Unit 

2 1 ...................................... 0.07 

PacifiCorp Huntington Plant/

Unit 1 1 .............................. 0.07 

PacifiCorp Huntington Plant/

Unit 2 1 .............................. 0.07 

1The owners and operators of PacifiCorp 

Hunter Units 1 and 2 and Huntington Units 1 

and 2, shall comply with the NOX emission 

limit for BART of 0.07 lb/MMBtu and other requirements of this section by August 4, 2021. 

(2) These emission limitations shall 

apply at all times, including startups, 

shutdowns, emergencies, and 

malfunctions. 

(d) Compliance date. (1) The owners 

and operators of PacifiCorp Hunter 

Units 1 and 2 shall comply with the 

NOX emission limitation of 0.07 lb/

MMBtu and other requirements of this 

section by August 4, 2021. The owners 

and operators of PacifiCorp Huntington 

Units 1 and 2 shall comply with the 

NOX emission limitation of 0.07 lb/

MMBtu and other requirements of this 

section by August 4, 2021. 

(2) [Reserved] 

(e) Compliance determinations for 

NOX. (1) For all BART units: 

(i) CEMS. At all times after the earliest 

compliance date specified in paragraph 

(d) of this section, the owner/operator of 

each unit shall maintain, calibrate, and 

operate a CEMS, in full compliance with 

the requirements found at 40 CFR part 

75, to accurately measure NOX, diluent, 

and stack gas volumetric flow rate from 

each unit. The CEMS shall be used to 

determine compliance with the 

emission limitations in paragraph (c) of 

this section for each unit. 

(ii) Method. (A) For any hour in 

which fuel is combusted in a unit, the 

owner/operator of each unit shall 

calculate the hourly average NOX

emission rate in lb/MMBtu at the CEMS 

in accordance with the requirements of 

40 CFR part 75. At the end of each 

operating day, the owner/operator shall 

calculate and record a new 30-day 

rolling average emission rate in lb/

MMBtu from the arithmetic average of 

all valid hourly emission rates from the 

CEMS for the current operating day and 

the previous 29 successive operating 

days. 

(B) An hourly average NOX emission 

rate in lb/MMBtu is valid only if the 

minimum number of data points, as 

specified in 40 CFR part 75, is acquired 

by both the pollutant concentration 


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Federal Register / Vol. 81, No. 128 / Tuesday, July 5, 2016 / Rules and Regulations 43925 

monitor (NOX) and the diluent monitor 

(O2 or CO2). 

(C) Data reported to meet the 

requirements of this section shall not 

include data substituted using the 

missing data substitution procedures of 

subpart D of 40 CFR part 75, nor shall 

the data have been bias adjusted 

according to the procedures of 40 CFR 

part 75. 

(2) [Reserved] 

(f) Recordkeeping. The owner/

operator shall maintain the following 

records for at least five years: 

(1) All CEMS data, including the date, 

place, and time of sampling or 

measurement; parameters sampled or 

measured; and results. 

(2) Records of quality assurance and 

quality control activities for emissions 

measuring systems including, but not 

limited to, any records required by 40 

CFR part 75. 

(3) Records of all major maintenance 

activities conducted on emission units, 

air pollution control equipment, and 

CEMS. 

(4) Any other CEMS records required 

by 40 CFR part 75. 

(g) Reporting. All reports under this 

section shall be submitted to the 

Director, Office of Enforcement, 

Compliance and Environmental Justice, 

U.S. Environmental Protection Agency, 

Region 8, Mail Code 8ENF–AT, 1595 

Wynkoop Street, Denver, Colorado 

80202–1129. 

(1) The owner/operator of each unit 

shall submit quarterly excess emissions 

reports for NOX BART units no later 

than the 30th day following the end of 

each calendar quarter. Excess emissions 

means emissions that exceed the 

emissions limits specified in paragraph 

(c) of this section. The reports shall 

include the magnitude, date(s), and 

duration of each period of excess 

emissions, specific identification of 

each period of excess emissions that 

occurs during startups, shutdowns, and 

malfunctions of the unit, the nature and 

cause of any malfunction (if known), 

and the corrective action taken or 

preventative measures adopted. 

(2) The owner/operator of each unit 

shall submit quarterly CEMS 

performance reports, to include dates 

and duration of each period during 

which the CEMS was inoperative 

(except for zero and span adjustments 

and calibration checks), reason(s) why 

the CEMS was inoperative and steps 

taken to prevent recurrence, and any 

CEMS repairs or adjustments. The 

owner/operator of each unit shall also 

submit results of any CEMS 

performance tests required by 40 CFR 

part 75. 

(3) When no excess emissions have 

occurred or the CEMS has not been 

inoperative, repaired, or adjusted during 

the reporting period, such information 

shall be stated in the quarterly reports 

required by paragraphs (g)(1) and (2) of 

this section. 

(h) Notifications. (1) The owner/

operator shall promptly submit 

notification of commencement of 

construction of any equipment which is 

being constructed to comply with the 

NOX emission limits in paragraph (c) of 

this section. 

(2) The owner/operator shall 

promptly submit semi-annual progress 

reports on construction of any such 

equipment. 

(3) The owner/operator shall 

promptly submit notification of initial 

startup of any such equipment. 

(i) Equipment operation. At all times, 

the owner/operator shall maintain each 

unit, including associated air pollution 

control equipment, in a manner 

consistent with good air pollution 

control practices for minimizing 

emissions. 

(j) Credible evidence. Nothing in this 

section shall preclude the use, including 

the exclusive use, of any credible 

evidence or information, relevant to 

whether a source would have been in 

compliance with requirements of this 

section if the appropriate performance 

or compliance test procedures or 

method had been performed. 

[FR Doc. 2016–14645 Filed 7–1–16; 8:45 am] 

BILLING CODE 6560–50–P 


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