Federal Register / Vol. 89, No. 226 / Friday, November 22, 2024 / Rules and Regulations 92573 

annually and rates each agency’s 

responsiveness to small business. If you 

wish to comment on actions by 

employees of the Coast Guard, call 1– 

888–REG–FAIR (1–888–734–3247). The 

Coast Guard will not retaliate against 

small entities that question or complain 

about this rule or any policy or action 

of the Coast Guard. 

C. Collection of Information 

This rule will not call for a new 

collection of information under the 

Paperwork Reduction Act of 1995 (44 

U.S.C. 3501–3520). 

D. Federalism and Indian Tribal 

Governments 

A rule has implications for federalism 

under Executive Order 13132, 

Federalism, if it has a substantial, direct 

effect 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. We have 

analyzed this rule under that order and 

have determined that it is consistent 

with the fundamental federalism 

principles and preemption requirements 

described in Executive Order 13132. 

Also, this rule does not have tribal 

implications under Executive Order 

13175, Consultation and Coordination 

with Indian Tribal Governments, 

because it does not have a substantial 

direct effect on one or more Indian 

tribes, on the relationship between the 

Federal Government and Indian tribes, 

or on the distribution of power and 

responsibilities between the Federal 

Government and Indian tribes. If you 

believe this rule has implications for 

federalism or Indian tribes, please 

contact the person listed in the FOR

FURTHER INFORMATION CONTACT section 

above. 

E. Unfunded Mandates Reform Act 

The Unfunded Mandates Reform Act 

of 1995 (2 U.S.C. 1531–1538) requires 

Federal agencies to assess the effects of 

their discretionary regulatory actions. In 

particular, the Act addresses actions 

that may result in the expenditure by a 

State, local, or tribal government, in the 

aggregate, or by the private sector of 

$100,000,000 (adjusted for inflation) or 

more in any one year. Though this rule 

will not result in such an expenditure, 

we do discuss the effects of this rule 

elsewhere in this preamble. 

F. Environment 

We have analyzed this rule under 

Department of Homeland Security 

Directive 023–01 and Environmental 

Planning COMDTINST 5090.1 (series), 

which guide the Coast Guard in 

complying with the National 

Environmental Policy Act of 1969 (42 

U.S.C. 4321–4370f) and have 

determined that this action is one of a 

category of actions that do not 

individually or cumulatively have a 

significant effect on the human 

environment. This rule involves 

establishment of two temporary safety 

zones for navigable waters in the Gulf of 

Mexico and South Bay. The safety zones 

are needed to protect personnel, vessels, 

and the marine environment from 

potential hazards created by rocket 

launching activity that may include free 

falling debris and/or descending 

vehicles or vehicle components under 

various means of control. It is 

categorically excluded from further 

review under paragraph L60(c), in 

Appendix A, Table 1 of DHS Instruction 

Manual 023–01–001–01, Rev. 1. A 

Record of Environmental Consideration 

is available for viewing in the docket. 

For instructions on how to locate it, see 

the ADDRESSES section above. 

G. Protest Activities 

The Coast Guard respects the First 

Amendment rights of protesters. 

Protesters are asked to contact the 

person listed in the FOR FURTHER

INFORMATION CONTACT section to 

coordinate protest activities so that your 

message can be received without 

jeopardizing the safety or security of 

people, places, or vessels. 

List of Subjects in 33 CFR Part 165 

Harbors, Marine safety, Navigation 

(water), Reporting and recordkeeping 

requirements, Security measures, 

Waterways. 

For the reasons discussed in the 

preamble, the Coast Guard amends 33 

CFR part 165 as follows: 

PART 165–REGULATED NAVIGATION 

AREAS AND LIMITED ACCESS AREAS 

■ 1. The authority citation for part 165 

continues to read as follows: 

Authority: 46 U.S.C. 70034, 70051, 70124; 

33 CFR 1.05–1, 6.04–1, 6.04–6, and 160.5; 

Department of Homeland Security Delegation 

No. 00170.1, Revision No. 01.3. 

■ 2. Add § 165.T08–1021 to read as 

follows: 

§ 165.T08–1021 Safety Zones; Gulf of 

Mexico and South Bay, Boca Chica Beach, 

TX. 

(a) Location. The following areas are 

safety zones: Safety Zone A consists of 

all navigable waters of the Gulf of 

Mexico, from the surface to bottom, 

encompassed by a line connecting the 

following points beginning at Point 1: 

26°2′36′′ N 097°9′8′′ W, thence to Point 

2: 26°3′0′′ N 097°7′10′′ W, thence to 

Point 3: 26°7′0′′ N 097°57′0′′ W, thence 

to Point 4: 26°6′54′′ N 096°55′46′′ W, 

thence following the 12NM line to 

United States of America/Mexico 

Maritime Boundary Line, thence 

following the United States of America/ 

Mexico Maritime Boundary Line to 

Point 5: 25°57′24.2′′ N 097°8′49′′ W, 

thence following the coast to Point 1. 

Safety Zone B consists of all navigable 

waters of South Bay, from the surface to 

bottom, encompassed by a line 

connecting the following points 

beginning at Point 6: 26°2′45′′ N 

097°11′6.3′′ W, thence to Point 7: 

26°2′45′′ N 097°10′53.4′′ W, thence 

following the coastline to Point 6. These 

coordinates are based on World 

Geodetic System (WGS) 84. 

(b) Enforcement period. This section 

will be subject to enforcement from 2 

p.m. to 6 p.m. each day from November 

18, 2024, through November 22, 2024, 

and November 25, 2024, and from 11 

a.m. to 3 p.m. each day from November 

23, 2024, through November 24, 2025. 

(c) Regulations. (1) In accordance with 

the general regulations in § 165.23, entry 

into the temporary safety zones is 

prohibited unless authorized by the 

Captain of the Port, Sector Corpus 

Christi (COTP) or a designated 

representative. They may be contacted 

on Channel 16 VHF–FM (156.8 MHz) or 

by telephone at 361–939–0450. 

(2) If permission is granted, all 

persons and vessels shall comply with 

the instructions of the COTP or 

designated representative. 

(d) Information broadcasts. The COTP 

or a designated representative will 

inform the public of the enforcement 

times and date for the safety zone 

through Broadcast Notices to Mariners 

and Safety Marine Information 

Broadcasts. 

Dated: November 17, 2024. 

T.H. Bertheau, 

Captain, U.S. Coast Guard, Captain of the 

Port, Sector Corpus Christi. 

[FR Doc. 2024–27454 Filed 11–20–24; 8:45 am] 

BILLING CODE 9110–04–P 

ENVIRONMENTAL PROTECTION 

AGENCY 

40 CFR Part 52 

[EPA–R04–OAR–2022–0786; FRL–10405– 

02–R4] 

Air Plan Partial Approval and Partial 

Disapproval; North Carolina; Second 

Period Regional Haze Plan 

AGENCY: Environmental Protection 

Agency (EPA). 


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1 In a letter dated August 15, 2022, EPA found 

that North Carolina’s Haze Plan meets the 

completeness criteria outlined in 40 CFR part 51, 

appendix V. A completeness determination does 

not constitute a finding on the merits of the 

submission or whether it meets the relevant criteria 

for SIP approval. The August 15, 2022, letter is 

included in the docket for this rulemaking. 

2The Commitment Letter is in the docket for this 

rulemaking. 

3Under CAA section 110(k)(4), EPA may 

conditionally approve a SIP revision based on a 

commitment from a state to adopt specific 

enforceable measures by a date certain, but not later 

than one year from the date of conditional approval 

of the plan revision. In its Commitment Letter, the 

State committed to submit a SIP revision containing 

specific enforceable measures no later than one year 

from the effective date of a final conditional 

approval action. Because EPA is not finalizing the 

proposed conditional approval, North Carolina is 

not required to submit that SIP revision. 

4North Carolina’s Haze Plan was not submitted 

to address a requirement of part D, title I of the 

CAA, and is not required in response to a finding 

of substantial inadequacy as described in CAA 

section 110(k)(5) (SIP Call), so the partial 

disapproval will not trigger any offset or highway 

sanctions clocks. See CAA section 179(a). 

ACTION: Final rule. 

SUMMARY: The Environmental Protection 

Agency (EPA) is approving in part and 

disapproving in part a regional haze 

State Implementation Plan (SIP) 

revision submitted by the North 

Carolina Department of Environmental 

Quality, Division of Air Quality (DAQ), 

dated April 4, 2022 (‘‘Haze Plan’’ or 

‘‘2022 Plan’’) under the Clean Air Act 

(CAA or Act) and EPA’s Regional Haze 

Rule (RHR) for the regional haze 

program’s second planning period. 

North Carolina’s 2022 SIP submission 

was submitted to address the 

requirement that states must 

periodically revise their long-term 

strategies for making reasonable 

progress toward the national goal of 

preventing any future, and remedying 

any existing, anthropogenic impairment 

of visibility, including regional haze, in 

mandatory Class I Federal areas 

(hereinafter referred to as ‘‘Class I 

areas’’). The SIP submission also 

addresses other applicable requirements 

for the second planning period of the 

regional haze program. EPA is taking 

this action pursuant to sections 110 and 

169A of the Act. 

DATES: This rule is effective December 

23, 2024. 

ADDRESSES: EPA has established a 

docket for this action under Docket 

Identification No. EPA–R04–OAR– 

2022–0786. All documents in the docket 

are listed on the regulations.gov 

website. Although listed in the index, 

some information may not be publicly 

available, i.e., Confidential Business 

Information or other information whose 

disclosure is restricted by statute. 

Certain other material, such as 

copyrighted material, is not placed on 

the internet and will be publicly 

available only in hard copy form. 

Publicly available docket materials are 

available either electronically through 

www.regulations.gov or in hard copy at 

the Air Regulatory Management Section, 

Air Planning and Implementation 

Branch, Air and Radiation Division, 

U.S. Environmental Protection Agency, 

Region 4, 61 Forsyth Street SW, Atlanta, 

Georgia 30303–8960. EPA requests that, 

if at all possible, you contact the person 

listed in the FOR FURTHER INFORMATION

CONTACT section to schedule your 

inspection. The Regional Office’s 

official hours of business are Monday 

through Friday 8:30 a.m. to 4:30 p.m., 

excluding Federal holidays. 

FOR FURTHER INFORMATION CONTACT: 

Michele Notarianni, Multi-Air Pollutant 

Coordination Section, Air Planning and 

Implementation Branch, Air and 

Radiation Division, U.S. Environmental 

Protection Agency, Region 4, 61 Forsyth 

Street SW, Atlanta, Georgia 30303–8960. 

Ms. Notarianni can be reached via 

telephone at (404) 562–9031 or 

electronic mail at notarianni.michele@

epa.gov. 

SUPPLEMENTARY INFORMATION: 

I. Background 

On April 4, 2022, the North Carolina 

DAQ submitted a revision to its SIP to 

address regional haze for the second 

planning period. DAQ made this SIP 

submission to satisfy the requirements 

of the CAA’s regional haze program 

pursuant to CAA sections 169A and 

169B and 40 Code of Federal 

Regulations (CFR) 51.308.1

Subsequently, North Carolina submitted 

a letter, dated July 30, 2024 

(Commitment Letter), requesting partial 

conditional approval of its Haze Plan 

and committing to submit a SIP revision 

containing specific enforceable 

measures no later than one year from 

the effective date of a final conditional 

approval action.2 Through a notice of 

proposed rulemaking published on 

August 20, 2024, (89 FR 67341) 

(hereinafter referred to as the NPRM), 

EPA proposed to approve in part and 

conditionally approve in part North 

Carolina’s April 4, 2022, SIP submission 

addressing the regional haze 

requirements for the second planning 

period contained in the CAA and 40 

CFR 51.308. Comments on the NPRM 

were due on or before September 19, 

2024. EPA received four sets of relevant 

comments on the NPRM. 

After reviewing the entirety of the 

record including comments submitted, 

EPA is now taking final action to 

approve in part and disapprove in part 

North Carolina’s Haze Plan. 

Specifically, EPA is approving the 

portions of the Haze Plan addressing the 

requirements of 40 CFR 51.308(f)(1), 

(f)(4) through (6), and (g)(1) through (5). 

EPA is disapproving the portions of the 

Haze Plan addressing the requirements 

of 40 CFR 51.308(f)(2) and (3) and (i)(2) 

through (4) due to the inadequate record 

associated with the four-factor analysis 

(FFA) for Domtar Paper, LLC (Domtar) 

located in Plymouth, North Carolina, as 

described in more detail in section II. 

EPA is not finalizing its previously 

proposed conditional approval.3

Therefore, the issues identified as part 

of the proposed conditional approval 

and in the Commitment Letter are now 

subsumed under the broader partial 

disapproval. 

Disapproving a SIP submission 

establishes a two-year deadline for EPA 

to promulgate a Federal Implementation 

Plan (FIP) to address the relevant 

requirements under CAA section 110(c), 

unless EPA approves a subsequent SIP 

submission that meets these 

requirements.4 Therefore, EPA will be 

obligated under CAA section 110(c)(1) 

to promulgate a FIP within two years 

after the effective date of this partial 

disapproval, unless the State submits, 

and EPA approves, a SIP revision that 

satisfies the requirements of 40 CFR 

51.308(f)(2) and (3) and (i)(2) through 

(4). 

This final action represents a logical 

outgrowth of the proposal, following 

EPA’s proposed partial approval and 

partial conditional approval, and receipt 

of public comments. EPA specifically 

solicited comments on the adequacy of 

DAQ’s analyses, including the FFAs, 

determination of controls necessary for 

reasonable progress, and the adequacy 

of the submitted permit conditions, 

including associated monitoring, 

recordkeeping, and reporting, and 

whether the State met the requirements 

of 40 CFR 51.308(f)(2)(i) through (iv). 

See 89 FR 67358. Through this 

solicitation of comment, the public was 

on notice that EPA was specifically 

interested in the public’s perspective on 

its conclusions and may ultimately 

change its conclusions. A logical 

outgrowth of a proposal is to refrain 

from taking the proposed step. See Am. 

Iron & Steel Inst. v. EPA, 886 F.2d 390, 

400 (D.C. Cir. 1989). For action on SIP 

submittals, EPA is required to act, so the 

Agency may not refrain from acting. As 

such, it is reasonable to view a 

disapproval as a logical outgrowth of a 

proposed approval (or proposed 

conditional approval) if comments 


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5Exhibit 11 of the Conservation Groups’ 

comments contains the May 12, 2021, letter 

regarding the VISTAS regional haze modeling for 

the second planning period. 6The amount of progress that is ‘‘reasonable 

progress’’ is based on applying the four statutory 

factors in CAA section 169A(g)(1) in an evaluation 

of potential control options for sources of visibility 

impairing pollutants, which is referred to as a 

‘‘four-factor analysis.’’ 

7Areas statutorily designated as mandatory 

Federal Class I areas consist of national parks 

exceeding 6,000 acres, wilderness areas and 

national memorial parks exceeding 5,000 acres, and 

all international parks that were in existence on 

August 7, 1977. CAA section 162(a). There are 156 

mandatory Class I areas. The list of areas to which 

the requirements of the visibility protection 

program apply is in 40 CFR part 81, subpart D. 

8 ‘‘Modeling Guidance for Demonstrating Air 

Quality Goals for Ozone, PM2.5 and Regional Haze,’’ 

EPA 454/R–18–009, November 29, 2018, available 

at: https://www.epa.gov/sites/default/files/2020-10/ 

documents/o3-pm-rh-modeling_guidance-2018.pdf. 

9The April 3, 2018, Quality Assurance Project 

Plan for the VISTAS II Regional Haze Project is 

located in appendix A–1 of the Haze Plan. 

10North Carolina has five Class I areas, two of 

which are shared with Tennessee: Great Smoky 

Mountains (North Carolina/Tennessee); Linville 

Gorge; Swanquarter; Shining Rock National 

Wilderness Area (Shining Rock); and Joyce KilmerSlickrock National Wilderness Area (Joyce Kilmer) 

(North Carolina/Tennessee). Joyce Kilmer relies on 

data from the Great Smoky Mountains IMPROVE 

monitoring site (GRSM1) because it does not have 

an IMPROVE monitor and the Shining Rock 

IMPROVE monitor did not have valid data in 2011 

so model performance could not be evaluated. 

11See 2018 Modeling Guidance at p. 69 (‘‘Further, 

even with a single performance test, it is not 

appropriate to assign ‘‘bright line’’ criteria that 

distinguish between adequate and inadequate 

model performance.’’). 

cause EPA to change its proposed 

conclusions. Consistent with CAA 

section 110(k)(3), EPA may approve in 

part portions of the SIP submittal if 

those portions meet all applicable 

requirements. 

II. Response to Comments 

In response to the NPRM, EPA 

received comment letters from the 

National Parks Conservation 

Association (NPCA), Sierra Club, the 

Coalition to Protect America’s National 

Parks, Center for Biological Diversity, 

and Southern Environmental Law 

Center (collectively referred to as the 

‘‘Conservation Groups’’); U.S. National 

Park Service (NPS); and 7 Directions of 

Service, Blue Ridge Outdoors Magazine, 

Center for Biological Diversity, 

CleanAIRE NC, Coalition to Protect 

America’s National Parks, Dogwood 

Alliance, Forest Keeper, Friends of Big 

Ivy, I Heart Pisgah, Mountain True, 

NPCA, North Carolina Black Alliance, 

and Toxic Free North Carolina 

(collectively referred to as the 

‘‘Organizations’’). Additionally, EPA 

received comments from two members 

of the public. One set of comments from 

a member of the public is not relevant 

to this action, and the other set of 

comments is addressed below. All 

comments received are available in the 

docket for this action. A summary of the 

significant comments received from 

these commenters and EPA’s responses 

to these comments is below. 

Comment 1: The Conservation Groups 

contend that EPA’s proposal to approve 

North Carolina’s reliance on the 

Visibility Improvement State and Tribal 

Association of the Southeast’s 

(VISTAS’) visibility modeling is 

arbitrary and capricious because the 

Agency ignored significant flaws in this 

modeling. They state that they informed 

VISTAS and EPA of significant errors in 

the visibility modeling through a 2021 

letter,5 EPA did not acknowledge these 

errors in the NPRM, and these errors 

affected the source selection process for 

all of the VISTAS states. Consequently, 

they assert that North Carolina 

improperly excluded major sources of 

haze-forming pollution from FFAs.6

These alleged errors are addressed in 

comments 1.a through 1.c below. 

Comment 1.a: The Conservation 

Groups contend that the VISTAS 

modeling significantly underpredicted 

the contribution of sulfates to visibility 

impairment at Class I areas on the 20 

percent most impaired days and that 

this underprediction was largest during 

the summer months when visibility 

impairment is most problematic.7 They 

also assert that these errors resulted in 

the modeling not meeting VISTAS’ 

model performance goals and modeling 

acceptance criteria for a number of Class 

I areas. They further assert that although 

North Carolina claims that it corrected 

for this underprediction through the use 

of relative response factors (RRFs), 

neither North Carolina nor EPA assessed 

whether use of RRFs adequately 

corrected for errors in the modeling. 

Response 1.a: EPA disagrees that 

there are significant flaws in North 

Carolina’s 2028 visibility modeling that 

resulted in excluding major sources of 

haze-forming pollution from evaluation 

via FFAs for the second planning 

period. As the Conservation Groups 

state, North Carolina relied upon the 

photochemical visibility modeling 

performed by VISTAS to project the 

impact of the State’s 2028 sulfur dioxide 

(SO2) and nitrogen oxides (NOX) 

emissions on visibility in both in-state 

and out-of-state Class I areas. VISTAS 

performed the modeling in accordance 

with the principles described within 

EPA’s ‘‘Modeling Guidance for 

Demonstrating Air Quality Goals for 

Ozone, PM2.5 and Regional Haze’’ (2018 

Modeling Guidance).8 In 2018, EPA 

approved 9 the Quality Assurance 

Project Plan prepared by VISTAS for 

performing the modeling and also 

reviewed and provided comments on 

the VISTAS Modeling Protocol. EPA 

also reviewed the VISTAS final 

modeling reports and data relied upon 

by North Carolina, and they appear 

reasonable. 

Regarding sulfate predictions, figure 

6–7 in North Carolina’s Haze Plan 

shows the results of the normalized 

mean bias and normalized mean error 

statistical model performance tests for 

sulfates across the VISTAS region. 

Figure 6–7 does show that the modeled 

sulfate levels are biased low, with some 

values falling outside of the model 

performance criteria. However, as 

discussed below, these biases are not 

uncommon in photochemical modeling 

analyses and can be addressed with 

additional analyses. Table 6–10 in the 

Haze Plan summarizes the sulfate model 

performance criteria for multiple 

statistical tests, and figures 6–32 

through 6–55 in the Haze Plan 

graphically depict model performance at 

the Great Smoky Mountains National 

Park (Great Smoky Mountains) (North 

Carolina/Tennessee); Linville Gorge 

National Wilderness Area (Linville 

Gorge); and Swanquarter National 

Wilderness Area (Swanquarter) which 

are three of the five Class I areas in 

North Carolina.10

Model bias and error, either high or 

low, is not uncommon in photochemical 

modeling analyses due to uncertainties 

in model inputs and the scientific 

model formulation, and the fact that all 

air quality models are simplified 

approximations of the complex 

phenomena of atmospheric chemistry, 

fate, and transport of pollutants. Section 

6.0 of EPA’s 2018 Modeling Guidance 

discusses uncertainties that may affect 

model results and states that following 

the recommendations in the Guidance 

should help mitigate the uncertainty as 

much as possible. North Carolina 

acknowledges in the Haze Plan that 

model performance is biased low on the 

20 percent most impaired days and 

provided an explanation of why this 

modeling was nonetheless appropriate 

for its regulatory determinations in the 

Haze Plan (which references the 2018 

Modeling Guidance in several 

instances). The 2018 Modeling 

Guidance states that it is not appropriate 

to use a ‘‘bright-line test’’ for 

distinguishing between adequate and 

inadequate photochemical model 

performance for a single performance 

test statistic.11 EPA’s 2018 Modeling 

Guidance instead recommends using a 

‘‘weight of evidence’’ approach for 


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12See id. (‘‘[T]he EPA recommends that a ‘‘weight 

of evidence’’ approach be used to determine 

whether a particular modeling application is valid 

for assessing the future attainment status of an 

area.’’). 

13See id. at p. 103. 

14 IMPROVE visibility monitoring data is 

available at: https://vista.cira.colostate.edu/ 

Improve/. 

15See ‘‘Timeline’’ for the VISTAS II Regional 

Haze Project at: https://www.metro4-sesarm.org/ 

content/vistas-regional-haze-project-intro. 

16See ‘‘Technical Support Document for EPA’s 

Updated 2028 Regional Haze Modeling’’ at: https:// 

www.epa.gov/visibility/technical-supportdocument-epas-updated-2028-regional-hazemodeling. 

17For more information on the NEI, see: https:// 

www.epa.gov/air-emissions-inventories/nationalemissions-inventory-nei. 

18See Haze Plan at p. 24 (‘‘The year 2011 was 

selected as the modeling base year because the 

VISTAS 2028 emissions inventory is based on the 

2011 Version 6 EPA modeling platform, which at 

the commencement of the VISTAS second round of 

planning for regional haze was the most current, 

complete modeling platform available. For the 

analyses in this SIP, this period consists of those 

years surrounding 2011 (i.e., 2009–2013).’’). See 

also Haze Plan, p. 49 (‘‘Calendar year 2011 satisfies 

the criteria in EPA’s modeling guidance episode 

selection discussion and is consistent with the base 

year modeling platform. In addition, the 2011/2028 

modeling platform was the most recent available 

platform when VISTAS started its modeling work. 

EPA’s 2016-based platform became available at a 

later date after VISTAS had already invested a 

considerable amount of time and money into the 

modeling analysis. Using the 2016-based platform 

was not feasible from a monetary perspective, nor 

could such work be done in a timely manner.’’). 

19See the January 29, 2018, email from EPA 

(Richard Wayland) regarding use of a 2011 base 

year by VISTAS for regional haze in the docket for 

this rulemaking. 

evaluating model performance 

holistically.12

As discussed in section 5.2(d) of 

EPA’s ‘‘Guideline on Air Quality 

Models’’ contained in 40 CFR part 51, 

appendix W, there are no specific levels 

of any model performance metric that 

indicate acceptable model performance. 

The decision regarding acceptability is 

heavily influenced by professional 

judgment of the reviewing authority, 

which is EPA in this case. Based upon 

the overall performance of the model for 

all pollutants affecting visibility, 

considered holistically, North Carolina’s 

conclusions that the modeling is 

acceptable for use in the regional haze 

SIP analyses appear reasonable, and 

North Carolina provided a reasonable 

explanation of the model bias. 

Just as importantly, North Carolina’s 

steps to correct for this model bias 

appear reasonable. The Haze Plan 

explains that the model is applied in a 

relative sense through the calculation of 

RRFs following the procedures in 2018 

Modeling Guidance for calculating 2028 

future year visibility impacts, which 

mitigates concerns about the low bias in 

the sulfate model predictions. As 

described in EPA’s 2018 Modeling 

Guidance, RRFs are ‘‘the fractional 

change in air quality concentrations that 

is simulated due to emissions changes 

between a base and a future year 

emissions scenario.’’ 13

Applying the model in a relative 

sense using the RRFs is an important 

tool in mitigating the impacts of the 

sulfate modeling underpredictions in 

the 2011 baseline year on the model 

projections for the 2028 future year. 

Section 4.1 of the 2018 Modeling 

Guidance provides a detailed 

explanation of why EPA recommends 

photochemical modeling be applied in a 

relative sense and explains that 

problems posed by model bias are 

expected to be reduced when using the 

relative approach. Section 7.2.6.1 of 

North Carolina’s Haze Plan explains the 

calculation of 2028 visibility estimates 

using the RRF approaches contained in 

EPA’s 2018 Modeling Guidance. Using 

the RRF approach with an average of 

five years of Interagency Monitoring of 

Protected Visual Environments 

(IMPROVE) 14 data on the 20 percent 

most impaired days and 20 percent 

clearest days along with the relative 

percent modeled change in all of the 

particulate matter (PM) species between 

2011 and 2028 reduces the influence of 

the low bias in sulfate-modeled (and 

other PM species) values in the 2011 

baseline year. The 2028 visibility 

impairment projection is derived 

primarily from the five-year average of 

actual IMPROVE monitoring data in 

2009–2013 that was then scaled in a 

relative sense by the modeling results. If 

the model was being applied in an 

absolute sense, the low bias in the 

sulfate modeled values would have a 

larger impact on the 2028 visibility 

projections. For these reasons, North 

Carolina’s use of the VISTAS model 

results to inform source selection 

appears reasonable due to the use of 

RRFs to minimize the impacts of model 

bias. 

Comment 1.b: The Conservation 

Groups state that VISTAS relied on an 

‘‘outdated’’ 2011 baseline year for its 

2028 future year emissions projections 

and assumed that electric generating 

units (EGUs) would operate in the exact 

same manner in 2028 as they did in 

2011. Thus, they assert that the model 

assumptions and results are incorrect 

because EGUs are likely to have 

different load utilization in 2028 than in 

2011. 

Response 1.b: North Carolina’s use of 

a 2011 base emissions inventory year to 

project emissions out to 2028 (the end 

of the second planning period) appears 

reasonable in this instance. Although it 

is always preferable to use the most 

recent information available for 

modeling, the 2011 baseline year 

inventory used by VISTAS was the 

latest region-wide inventory available at 

the time that North Carolina’s SIP 

submittal was being developed during 

the VISTAS technical work, which took 

place from December 2017 to February 

26, 2021.15 In EPA’s experience, 

coordination among states such as those 

in the VISTAS region takes time, and 

the modeling involved is timeconsuming, highly technical, and 

resource intensive. The modeling 

generally requires hundreds of hours of 

time to gather the model input data (e.g., 

emissions, meteorology, land-use, etc.), 

prepare modeling protocols, perform the 

modeling, and analyze the results. The 

computational resources to run 

photochemical models are also very 

large. ‘‘Mainframe’’ clusters of a large 

number of computer processors are 

required to run the models, and even 

using these powerful computers, it takes 

weeks of computer run-time for a fullyear model simulation. Additionally, 

EPA’s newer 2016-based modeling 

platform only became available in 

September 2019, after VISTAS had 

already invested a considerable amount 

of time and money into the regional 

haze modeling analysis.16 EPA develops 

the National Emissions Inventory (NEI) 

suitable for use in such models every 

three years.17 By design, the regional 

haze program requires states to spend 

significant time in the planning phase, 

and this generally necessitates the use of 

a baseline year that is substantially 

earlier than the date the state submits its 

SIP to EPA. 

In addition, there is no RHR 

requirement regarding the baseline year 

for regional photochemical modeling 

(nor is photochemical modeling 

required). At the time VISTAS began 

their regional haze modeling, EPA did 

not have a more recent baseline 

emissions inventory year available for 

state use in the second period regional 

haze plans. Furthermore, North Carolina 

explains the use of this particular 

baseline year and states that the 2011 

emissions inventory was the most 

recently available quality assured 

statewide emissions inventory when the 

VISTAS project began.18 Moreover, 

prior to using this data, the State 

discussed the selection of this baseline 

year emissions inventory and received 

confirmation from EPA to use this 

emissions inventory.19

The 2011 emissions inventory was 

used to estimate emissions of visibility 

impairing pollutants in 2028. VISTAS 

applied reductions expected from 


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20See 40 CFR 51.308(f)(2)(i). 

21Both of these approaches (AoI and PSAT) are 

example methods in EPA’s August 20, 2019, 

guidance titled: ‘‘Guidance on Regional Haze State 

Implementation Plans for the Second 

Implementation Period’’ (‘‘2019 Guidance’’) which 

is available at: https://www.epa.gov/sites/default/ 

files/2019-08/documents/8-20-2019_-_regional_

haze_guidance_final_guidance.pdf. See subsection 

‘‘b) Estimating baseline visibility impacts for source 

selection’’ on pages 12–15 of the 2019 Guidance. 

Photochemical modeling (zero-out and/or source 

apportionment is listed as item 4 on page 13 of the 

2019 Guidance. VISTAS’ AoI analyses involve 

items 1–3 on p. 13 of the 2019 Guidance. 

Federal and state regulations on the 

visibility impairing pollutants NOX, PM, 

and SO2. North Carolina’s 2028 

emissions projections are based on the 

State’s technical analysis of the 

anticipated emissions rates and level of 

activity for EGUs, other point sources, 

non-point sources, on-road sources, and 

off-road sources based on their 

emissions in the 2011 base year, 

considering growth and additional 

emissions controls to be in place by 

2028. In addition, the VISTAS 

emissions inventory for 2028 accounts 

for post-2011 emission reductions from 

promulgated Federal, state, local, and 

site-specific control programs. North 

Carolina’s modeling of the EGUs and 

non-EGUs for the growth factors appears 

reasonable. The 2011 baseline year to 

2028 future year emissions projections 

were modeled to account for projected 

changes in emissions over the second 

planning period. 

Although North Carolina used the 

2011 year as its emissions inventory 

base year, North Carolina also examined 

more recent emission inventory 

information for SO2 and NOX for the 

years 2017, 2018, and 2019 and 

compared these emissions to the 2028 

emission projections that were used for 

modeling purposes in section 7.7.3 and 

tables 7–41 and 7–42 of its Haze Plan. 

This appears compliant with 40 CFR 

51.308(f)(2)(iii) and is another backstop 

that helps to ensure that the State 

adequately considered more recent 

emissions inventory information. The 

technical information provided in the 

docket documents the projected 2028 

emissions inventory in the Haze Plan. 

Given the aforementioned reasons, the 

use of the 2011 baseline year by VISTAS 

(and thus North Carolina) appears 

reasonable. 

Comment 1.c: The Conservation 

Groups state that VISTAS used 

‘‘outdated’’ monitoring data for its 2028 

future year projections that did not 

reflect an observed shift in nitrate 

contribution to visibility impairment in 

the southeastern United States in the 

recent past. They therefore contend that 

this resulted in the exclusion of major 

NOX sources from the modeling results. 

Response 1.c: Regarding the 

Conservation Groups’ claims that the 

2009–2013 modeling base period did 

not reflect more recent changes in 

nitrate contributions, EPA discussed its 

views on this issue in detail in the 

NPRM. Nitrates are also discussed in 

response 3, below. EPA agrees that 

during the 2009–2013 timeframe, nitrate 

impacts have become more significant 

on some of the 20 percent most 

impaired days, especially taking into 

account the significant decrease in SO2

emissions and acknowledged this in the 

NPRM. However, North Carolina’s focus 

on SO2 emitting sources during this 

period appears reasonable because 

sulfates remain the dominant visibility 

impairing pollutant at the Class I areas 

affected by North Carolina. 

For the reasons discussed in 

responses 1.a through 1.c, the VISTAS 

modeling appears adequate for North 

Carolina’s use in selecting sources for a 

FFA for the second planning period. 

However, the requirement to consider 

the four factors in establishing the longterm strategy (LTS) at 40 CFR 

51.308(f)(2) and CAA section 169A(g)(1) 

encompasses the selection of sources for 

further analysis, and as discussed above, 

EPA is disapproving the portions of the 

Haze Plan addressing 40 CFR 

51.308(f)(2) due to the inadequate 

record associated with the Domtar FFA. 

Comment 2: The Conservation Groups 

claim the errors in the VISTAS 

modeling discussed in comment 1 above 

were carried forward into the source 

selection process for VISTAS states, 

including North Carolina, and that those 

errors caused VISTAS, and the states 

that relied on the VISTAS process, to 

improperly exclude sources from FFAs. 

In addition to the impact of the 

modeling errors, they state that North 

Carolina used VISTAS’ unreasonable 

source screening process using Area of 

Influence (AoI) and Particulate Matter 

Source Apportionment Technology 

(PSAT) analyses and unreasonably high 

source selection thresholds. They 

therefore contend that EPA’s proposal to 

approve the State’s source selection 

method is arbitrary and capricious. The 

Conservation Groups’ specific 

comments on this topic are addressed in 

comments 2.a through 2.g, below. 

Comment 2.a: The Conservation 

Groups claim that the State employed 

unreasonably high source selection 

thresholds for AoI, which were too 

restrictive and resulted in the 

identification of only five North 

Carolina sources at that step. They 

assert that by using a percentage source 

selection threshold, the calculated 

threshold in absolute visibility impact 

terms was higher for Class I areas with 

the most severe visibility impairment. 

The Conservation Groups contend that 

fewer sources were identified at the AoI 

step for Class I areas with the worst 

visibility impairment. They also state 

that for the areas with the worst 

visibility impairment, more sources 

should be selected to make progress 

toward the natural visibility goal. In 

addition, they assert that neither North 

Carolina nor EPA provide justification 

for a three percent threshold at the AoI 

step, making its use arbitrary. 

Response 2.a: EPA disagrees with this 

comment. As explained in the NPRM, 

the RHR does not require states to 

consider controls for all sources, all 

source categories, or any or all sources 

in a particular source category. See 89 

FR 67346. Nor does the RHR expressly 

specify criteria for minimum source 

selection thresholds. 

These flexibilities, however, are not 

unbounded. The RHR requires that 

‘‘[t]he State should consider evaluating 

major and minor stationary sources or 

groups of sources, mobile sources, and 

area sources. The State must include in 

its implementation plan a description of 

the criteria it used to determine which 

sources or groups of sources it evaluated 

and how the four factors were taken into 

consideration in selecting the measures 

for inclusion in its long-term 

strategy.’’ 20 In addition, the technical 

basis for source selection must also be 

documented, as required by 40 CFR 

51.308(f)(2)(iii), and North Carolina 

discussed the criteria it used to 

determine which sources or groups of 

sources were evaluated by the State, 

including the use of AoI analysis, 

photochemical modeling (e.g., PSAT), 

and associated source selection 

thresholds for AoI and PSAT tagging in 

its Haze Plan. North Carolina 

documented its use of these approaches 

in extensive detail within section 7.5 of 

the Haze Plan and appendices D–1 and 

D–2 of the Haze Plan (relating to AoI 

analysis) and section 7.6 of the Haze 

Plan and appendices E–1a, E–1b, E–2a, 

E–2b, E–2c, E–2d, E–2e, E–2f, E–3, E–4, 

E–5, E–6, E–7a, E–7b, and E–8 of the 

Haze Plan (relating to PSAT modeling). 

North Carolina’s source selection 

methodology—including the use of an 

AoI threshold of greater than or equal to 

three percent for sulfate and nitrate 

combined at any North Carolina Class I 

area for all sources within and outside 

of the State for follow-up PSAT tagging, 

and a one percent PSAT threshold on a 

pollutant-by-pollutant basis for source 

selection—appears reasonable and is 

documented in the Haze Plan. A 

specific approach is not required by the 

RHR.21


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22North Carolina selected sources for PSAT 

modeling based on the combined impact of sulfate 

plus nitrate. Sulfates and nitrates were modeled 

together in the PSAT modeling with the other PM 

species that impact visibility (e.g., direct PM, 

organic carbon, elemental carbon, etc.). There were 

no sources with a sulfate impact below the PSAT 

threshold(s), but a sulfate plus nitrate impact above 

the threshold(s). 

23On December 1, 2023, DAQ issued Air Quality 

Permit No. 04291T51 authorizing modifications to 

the Domtar facility, which is available at: https:// 

edocs.deq.nc.gov/AirQuality/ 

DocView.aspx?id=457541

&dbid=0&repo=AirQuality&searchid=c271acf8- 

6535-4306-8cfb-9a0caa2b3d97. Because these 

authorized permit modifications are subsequent to 

the North Carolina SIP submission, North Carolina 

did not consider the modification to determine 

reasonable progress in the second planning period. 

24These percentages were calculated by dividing 

the ‘‘NC’’ column by the ‘‘2028 Sulfate + Nitrate 

Impairment’’ column and multiplying by 100. 

25See Haze Plan at p. 227. 

The results of this methodology also 

appear reasonable. North Carolina 

selected for further analysis the three 

sources with the largest visibility 

impacts (accounting for both SO2/sulfate 

and NOX/nitrate 22) at North Carolina 

and nearby Class I areas. On the whole, 

SO2 emissions from the three in-state 

sources selected by North Carolina for 

FFAs—Blue Ridge Paper Products— 

Canton Mill (BRPP); Domtar; 23 and PCS 

Phosphate Inc.—Aurora (PCS)—are 

projected to impact visibility at Class I 

areas above North Carolina’s one 

percent PSAT threshold. 

Most anthropogenic impacts to 

visibility at the North Carolina Class I 

areas come from outside of North 

Carolina and, in fact, they primarily 

come from outside of the VISTAS states. 

This is also illustrated in table 7–14 of 

the Haze Plan, which provides the 

contributions from 2028 SO2 and NOX

emissions to visibility impairment from 

all source sectors for the 20 percent 

most impaired days in units of inverse 

megameters (Mm¥1). The entries in 

table 1, below, taken from table 7–14 of 

the Haze Plan, show the contributions 

made from North Carolina, all other 

VISTAS states, and other Regional 

Planning Organizations (RPOs) to North 

Carolina’s Class I areas. 

TABLE 1—CONTRIBUTIONS OF 2028 SO2 AND NOX EMISSIONS FROM ALL SOURCE SECTORS TO VISIBILITY IMPAIRMENT

FOR THE 20 PERCENT MOST IMPAIRED DAYS FOR CLASS I AREAS IN NORTH CAROLINA

[Mm¥1] * 

Class I area 

Sulfate + nitrate visibility impairment (Mm¥1) 

2028 total 

impairment 

(all species) 

2028 sulfate 

+ nitrate 

impairment 

NC 

All other 

VISTAS 

states 

CENRAP 

region ** 

LADCO 

region ** 

MANE-VU 

region ** 

Boundary + 

all other 

regions 

within 

VISTAS 

modeling 

domain 

Great Smoky Mountains ............................. 45.75 24.17 0.89 9.77 1.87 3.74 1.57 6.33 

Joyce Kilmer ................................................ 45.12 22.48 0.43 5.62 2.96 6.84 0.82 5.81 

Linville Gorge .............................................. 42.52 19.47 0.95 4.19 2.55 5.54 1.15 5.09 

Shining Rock ............................................... 42.09 19.20 1.13 3.97 2.80 5.11 0.75 5.44 

Swanquarter ................................................ 46.39 21.14 1.83 3.87 0.72 4.19 3.23 7.30 

* As noted in North Carolina’s Haze Plan, the columns to the right of ‘‘Projected 2028 Impairment on 20% Most Impaired Days’’ do not add up to the values in the 

‘‘Projected 2028 Impairment on 20% Most Impaired Days’’ column due to international emissions and boundary emissions. 

** ‘‘CENRAP’’ refers to Central Regional Air Planning Association (which is associated with the Central States Air Resource Agencies (CENSARA)); ‘‘LADCO’’ refers to Lake Michigan Air Directors Consortium; ‘‘MANE-VU’’ refers to Mid-Atlantic/Northeast Visibility Union; ‘‘WRAP’’ refers to Western Regional Air Partnership. See 

also: https://www.epa.gov/visibility/visibility-regional-planning-organizations. 

Table 1 illustrates that North 

Carolina’s in-state emissions account for 

a relatively small fraction of total sulfate 

plus nitrate visibility impairment at 

North Carolina’s Class I areas which is 

as follows: approximately 3.68 percent 

for Great Smoky Mountains; 1.91 

percent for Joyce Kilmer; 4.88 percent 

for Linville Gorge; 5.89 percent for 

Shining Rock; and 8.66 percent for 

Swanquarter.24

The RHR affords North Carolina 

flexibility in its choice of both AoI and 

PSAT thresholds. North Carolina’s 

source selection methodology appears 

reasonable, and therefore, North 

Carolina’s choice of the three largest 

impacting sources in the State using its 

AoI and PSAT criteria appears adequate. 

Comment 2.b: The Conservation 

Groups state that VISTAS considered 

sulfate and nitrate separately in the 

PSAT model analyses, which the 

Conservation Groups allege does not 

align with how these pollutants actually 

function in the atmosphere, where 

sulfate and nitrate act in combination, 

along with other precursors, to 

contribute to visibility impairment. As a 

result, they argue that VISTAS likely 

underestimated the overall visibility 

impact of individual sources in its 

PSAT analysis. 

Response 2.b: EPA disagrees with this 

comment. In the AoI screening analysis, 

VISTAS used the combined sulfate plus 

nitrate values to select sources to tag for 

the refined PSAT source apportionment 

modeling analyses. Section 7.5.5 of the 

Haze Plan explains how North Carolina 

used the results of the AoI analysis to 

select sources for further evaluation 

with PSAT. This section shows that 

facilities contributing greater than or 

equal to three percent for sulfate and 

nitrate combined at any North Carolina 

Class I area for all sources within and 

outside of the State were selected for 

PSAT tagging. See tables 7–20 through 

7–24 for the specific sources with 

sulfate plus nitrate values greater than 

North Carolina’s AoI source selection 

threshold. 

Also, contrary to the Conservation 

Groups’ assertion, sulfates and nitrates 

were modeled together in the PSAT 

modeling with the other PM species that 

impact visibility (e.g., direct PM, 

organic carbon, elemental carbon, etc.). 

Section 7.6.2 of the Haze Plan 

summarizes the results of the PSAT 

modeling. This section states that: ‘‘The 

adjusted PSAT results were used to 

calculate the percent contribution of 

each tagged facility to the total sulfate 

and nitrate point source (EGU + nonEGU) contribution at each Class I 

area.’’ 25 Tables 7–31 through 7–35 

contain the specific PSAT results for 

each of North Carolina’s Class I areas. It 

is true that North Carolina considered 

the PSAT modeled results for sulfate 

and nitrate separately to compare 

against its selected one percent 

threshold. However, no additional 

sources would have been identified by 

using a combined sulfate plus nitrate 

metric. For these reasons, North 

Carolina’s approach appears reasonable. 


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26See table 2 of the 2024 Kordzi Report in Exhibit 

1 of the Conservation Groups’ comment letter. 

27 ‘‘Clarification on the Development of Modeled 

Emission Rates for Precursors (MERPs) as a Tier 1 

Demonstration Tool for Ozone and PM2.5 under the 

PSD Permitting Program,’’ April 30, 2024, 

Memorandum from Tyler Fox to Regional Office 

Modeling Contacts is available at: https://

www.epa.gov/sites/default/files/2020-09/ 

documents/epa-454_r-19-003.pdf. 

28See https://www.epa.gov/cmaq for further 

information on CMAQ. 

29Memorandum from Richard A. Wayland to 

Regional Air Division Directors, ‘‘Availability of 

Modeling Data and Associated Technical Support 

Document for EPA’s Updated 2028 Visibility Air 

Quality Modeling,’’ September 19, 2019, available 

at: https://www.epa.gov/visibility/technicalsupport-document-epas-updated-2028-regionalhaze-modeling. 

30 ‘‘Documentation for EPA’s Power Sector 

Modeling Platform v6 Using the Integrated Planning 

Model,’’ November 2018, available at: https://

www.epa.gov/power-sector-modeling/ 

documentation-epas-power-sector-modelingplatform-v6-november-2018-reference. 

31EPA’s regulations define ‘‘Federal Land 

Manager’’ as ‘‘the Secretary of the department with 

authority over the Federal Class I area (or the 

Secretary’s designee) or, with respect to RooseveltCampobello International Park, the Chairman of the 

Continued 

Comment 2.c: The Conservation 

Groups state that VISTAS used an 

outdated 2028 emissions projection to 

‘‘tag’’ sources. They note that although 

VISTAS documented that the initial 

2028 emission inventory projections 

were updated for the final modeling, the 

associated PSAT modeling did not use 

the final 2028 inventory. They state that 

VISTAS scaled predicted sulfate and 

nitrate to the corresponding changes in 

SO2 and NOX emissions using a linear 

relationship between SO2 and NOX

emissions and sulfate and nitrate 

concentrations. They argue ample 

evidence shows that there is a nonlinear relationship between emissions 

and sulfate/nitrate concentrations. 

Moreover, the Conservation Groups 

contend that North Carolina 

significantly underestimated future 

2028 emissions for multiple sources, 

pointing to a comparison of North 

Carolina’s 2028 future emission 

projections against recent actual 

emissions for five Duke Energy EGUs as 

an example: Duke Energy Carolinas 

(DEC)—Belews Creek Steam Station 

(DEC—Belews Creek), DEC—Cliffside 

Steam Station (DEC—Cliffside), DEC— 

Marshall Steam Station (DEC— 

Marshall), Duke Energy Progress, LLC 

(DEP)—Mayo Electric Generating Plant 

(DEP—Mayo), and DEP—Roxboro Steam 

Electric Plant (DEP—Roxboro).26

They argue that this comparison 

shows that the State severely 

underestimated future emissions for 

these facilities and note that nothing in 

the Haze Plan indicates that there have 

been federally enforceable changes to 

these Duke Energy EGUs’ operating 

parameters that would justify such large 

differences between recent actual 

emissions and future year 2028 

projections. 

Response 2.c: Regarding the 

Conservation Groups’ claim that 

VISTAS used an outdated 2028 

emissions projection to select sources 

for the PSAT modeling and that the 

linear scaling used to adjust the PSAT 

results for the updated 2028 emissions 

inventory introduced errors into the 

modeling, EPA acknowledges that 

VISTAS used the original 2028 

emissions inventory to perform the 

PSAT modeling and that the original 

PSAT results were linearly scaled to 

reflect the updated 2028 emissions. 

Although linear scaling introduces some 

uncertainty to the final PSAT results, 

EPA agrees that adjusting the results to 

account for VISTAS’ updated 2028 

emissions inventory using linear scaling 

is a better approach than relying on the 

original PSAT modeling. Linear scaling 

of photochemical modeling results to 

account for changes in emissions is an 

accepted practice by EPA. An example 

is provided by EPA’s Modeled Emission 

Rates for Precursors (MERPs) for 

evaluating secondary particulate matter 

of 2.5 micrometers or less in diameter 

(PM2.5) impacts in Prevention of 

Significant Deterioration (PSD) 

modeling analyses.27 This guidance 

recommends an approach where the 

PM2.5 impacts are estimated using an 

archived national-scale photochemical 

modeling analysis, performed using 

Comprehensive Air Quality Model with 

Extensions (CAMx) and Community 

Multiscale Air Quality Modeling 

(CMAQ) 28 photochemical models, that 

uses hypothetical emissions sources, 

and then linearly scaling the 

photochemical modeling results using 

the ratio of the PSD project-specific 

source emissions to the modeled 

emissions from the hypothetical source 

(see Equation 1 on page 3 of the April 

30, 2024, MERPs memorandum). This 

approach is widely used and accepted 

by state air quality agencies and EPA to 

account for secondarily formed PM2.5

resulting from precursor emissions (SO2

and NOX) for PSD modeling analyses. 

Since the MERPs analyses use linear 

scaling with CAMx and for the same 

PM2.5 precursors (SO2 and NOX) as 

VISTAS used for their regional haze 

modeling, this example clearly shows 

that linear scaling of PM precursor 

emissions is an accepted practice. 

Regarding the Conservation Groups’ 

assertion that ‘‘[n]othing in the SIP 

Revision indicates that there have been 

federally enforceable changes to the 

Duke Energy EGUs’ operating 

parameters that would justify such large 

differences between recent actual 

emissions and future year 2028 

projections,’’ as explained in response 

4.f, under the RHR, sources that do not 

meet a state’s reasonable source 

selection criteria (such as these five 

Duke Energy EGUs) are not selected for 

a FFA and are therefore not required to 

have emission limits and supporting 

conditions adopted into the LTS in the 

SIP to support reasonable progress for 

the planning period. 

With respect to the 2028 emissions 

projections for the Duke Energy EGUs, 

North Carolina appears to have used the 

best assumptions available at the time of 

SIP development to project the 2011 

base year emissions out to 2028 for the 

five Duke Energy EGUs discussed in this 

response. The State compared 2017, 

2018, and 2019 actual SO2 and NOX

emissions to 2028 projected emissions 

in tables 7–41 and 7–42 of their Haze 

Plan. The methodology used to make 

the 2028 projections is discussed in 

appendix B–3 of North Carolina’s Haze 

Plan. Table 9 in appendix B–3 provides 

a comparison of the different projection 

methodologies used by North Carolina 

including a comparison to the 2028 

emissions projections performed 

separately by EPA for its 2028 Regional 

Haze Modeling.29 The total of North 

Carolina’s 2028 projected SO2 emissions 

for the five Duke Energy EGUs in table 

9 of appendix B–3 used for its 

reasonable progress and PSAT modeling 

(VISTAS 2028elv5 inventory) is 8,732 

tons per year (tpy), which is 

approximately eight percent less than 

the 9,456 tpy of emissions projected by 

EPA for 2028 for these five sources. 

EPA’s 2028 emissions for EGUs were 

projected from the more recent 2016 

base-year emissions inventory using the 

Integrated Planning Model.30 While 

North Carolina’s 2028 projection 

emissions are much less than the recent 

actual emissions in 2017–2019, North 

Carolina’s and EPA’s projected 2028 

projections are similar. Therefore, North 

Carolina’s 2028 emissions projections 

appear reasonable for the reasonable 

progress and PSAT modeling analyses. 

Comment 2.d: The Conservation 

Groups note that North Carolina relied 

on the PSAT modeling results for its 

multiple in-state sources that are located 

less than 50 kilometers (km) from a 

Class I area and claim that PSAT 

modeling has been shown to be 

unreliable for sources that are within a 

short distance from a Class I area, 

referencing Federal Land Manager 

(FLM) 31 guidance that addresses 


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Roosevelt-Campobello International Park 

Commission.’’ See 40 CFR 51.301. The U.S. 

National Park Service (NPS), U.S. Fish and Wildlife 

Service (FWS), and U.S. Forest Service (USFS) are 

collectively referred to as the ‘‘Federal Land 

Managers’’ or ‘‘FLMs’’ throughout this notice. 

32The Plume Visibility Model ‘‘PLUVUE’’ is used 

for estimating visual range reduction and 

atmospheric discoloration caused by plumes 

resulting from the emissions of particles, nitrogen 

oxides, and sulfur oxides from a single source. See 

‘‘PLUVUE II’’ at: https://www.epa.gov/scram/airquality-dispersion-modeling-alternative-models. 

The User’s Guide is available at: https://

gaftp.epa.gov/Air/aqmg/SCRAM/models/other/ 

pluvueii/PluvueUG.pdf. 

33See section 7.5 of the Haze Plan for additional 

detail. 

regional grid models. According to the 

Conservation Groups, this guidance 

shows that regional grid models are not 

preferred for sources located close to 

Class I areas and that the grid size used 

by VISTAS is too small to produce 

accurate results for those sources. 

Response 2.d: The Conservation 

Groups state that PSAT modeling has 

been shown to be unreliable for sources 

located less than 50 km from a Class I 

area, which caused North Carolina to 

inappropriately screen out sources 

which should have undergone an FFA. 

However, they do not provide any 

specific model performance information 

demonstrating that the CAMx model nor 

the PSAT source apportionment tool 

have poor model performance for 

evaluating visibility impacts from 

sources located within 50 km of any of 

the Class I areas located in North 

Carolina. 

Instead, the Conservation Groups 

provide qualitative arguments to 

support their assertion. They assert that 

the FLMs’ Air Quality Related Values 

Work Group (FLAG) Guidance indicates 

that photochemical grid models are not 

the preferred model for evaluating 

visibility impacts from sources less than 

50 km from Class I areas and reference 

the use of direct plume impact models. 

However, they are inappropriately citing 

the FLAG guidance and 

recommendations, which is not 

intended to apply to photochemical grid 

modeling or outside of the permitting 

context. The FLAG reference to direct 

plume models (e.g., Plume Visibility 

Model) 32 is only for evaluating 

visibility impacts under the New Source 

Review (NSR)/PSD (NSR/PSD) 

permitting regulations and is not 

applicable to regional haze analyses. 

EPA’s regional haze regulations and 

guidance do not require evaluations of 

direct plume impacts separate from the 

photochemical modeling analyses used 

for regional haze visibility analyses. 

Therefore, the argument is not relevant 

for the visibility analyses for regional 

haze. 

The Conservation Groups also assert 

that since the horizontal grid size used 

in the VISTAS CAMx modeling was 12 

km, it is insufficient to resolve the 

details of emissions plumes from 

facilities within 50 km of a Class I area 

and that the model performance 

degrades substantially at the close-in 

distances. The general statement from 

the Conservation Groups is that model 

performance substantially degrades 

within 50 km is not supported by any 

specific evidence in the comments. 

Therefore, North Carolina’s CAMx 

PSAT modeling appears reasonable for 

selecting sources for reasonable progress 

analyses. 

The Conservation Groups separately 

contend that North Carolina’s 

correlation analysis of the sulfate AoI 

versus PSAT presented in section 7.6.3 

of the Haze Plan is flawed. They point 

out the scatter in the AoI/PSAT ratio 

data for distances less than 100 km in 

figure 7–77 of the Haze Plan and argue 

this makes the State’s correlation 

conclusions invalid. They also refer to 

the scatter in the sulfate fractional bias 

values in figure 7–78 in the Haze Plan 

and argue the AoI versus PSAT 

correlation is invalid. EPA disagrees. 

While there is more scatter between the 

data points less than 100 km from the 

Class I area, there is clearly a trend that 

the AoI values are much larger than the 

PSAT values within 100 km compared 

to the ratios for further distances. There 

is logic to this result due to the way the 

AoI metric is calculated using the 

Extinction Weighted Residence Times 

(EWRT) multiplied by the Emissions (Q) 

divided Distance (d) (EWRTxQ/d). The 

EWRT is calculated using the frequency 

that winds (represented by Hybrid 

Single-Particle Lagrangian Integrated 

Trajectory (HYSPLIT) back trajectories) 

pass over a specific geographic area 

(represented by a modeling grid cell) on 

the path to the Class I area.33 For 

sources located less than 100 km from 

a Class I area, there is likely to be a 

higher frequency of the HYSPLIT back 

trajectories passing over the 12 km grid 

cell containing the source, thus the 

EWRT and AoI value will be larger. The 

CAMx PSAT modeling is a more refined 

photochemical modeling approach that 

calculates the atmospheric fate and 

transport of the PM precursors and their 

chemical reactions to form visibility 

impairing pollutants (e.g., ammonium 

sulfate). Therefore, compared to the AoI 

screening process, the refined PSAT 

technique is less likely to overestimate 

the visibility impacts for sources located 

within 100 km of the Class I area. 

Regarding the scatter of the data 

resulting in the AoI to PSAT fractional 

bias correlation, EPA acknowledges that 

there is scatter in the data which is 

reflected in the 0.72 coefficient of 

determination (R2) value shown in 

figure 7–78 in the Haze Plan. However, 

this level of correlation is not 

uncommon in these types of modeling 

data analyses, and the results are 

reasonable. For these reasons, North 

Carolina’s correlation approach appears 

valid. 

The photochemical modeling 

employed by VISTAS and North 

Carolina is the most refined 

methodology available for evaluating 

regional haze visibility impacts. 

Moreover, North Carolina’s AoI 

screening process identified sources 

located within 50 km of its Class I areas, 

including the BRPP facility located 

approximately 17 km from Swanquarter 

that met the PSAT source selection 

criteria and underwent an FFA to 

evaluate reasonable progress. As 

discussed above, North Carolina 

demonstrated in section 7.6.3 of the 

Haze Plan that the AoI screening 

technique tends to overestimate 

visibility impacts for sources located 

within 100 km of a Class I area. Based 

upon this AoI overestimation, in section 

7.7.3 of the Haze Plan, North Carolina 

explains why some sources located less 

than 100 km from its Class I areas were 

not tagged for PSAT modeling and thus 

were not selected for FFAs. North 

Carolina’s justification regarding why 

the other sources within 100 km were 

not selected for FFAs appears 

reasonable. 

Comment 2.e: The Conservation 

Groups claim that North Carolina did 

not justify its application of the one 

percent PSAT threshold and that North 

Carolina’s use of this threshold at the 

PSAT step biased the process against 

heavily polluted Class I areas. They note 

that NPS’ comments on the draft SIP 

revision explain that reliance on the 

percent-based threshold required source 

impacts to be 80 times larger for the 

most visually impaired Class I areas 

versus the least visually impaired Class 

I areas in order to be selected for an 

FFA. They also argue that PSAT tagging 

was unnecessary because the AoI step 

already identified the sources that 

contributed to impairment at Class I 

areas. 

Response 2.e: EPA disagrees with the 

Conservation Groups’ assertion that 

North Carolina did not justify its 

application of the one percent PSAT 

threshold. Section 7.7.1 of the Haze Plan 

explains the State’s rationale for using a 

one percent PSAT threshold to select 

sources for a reasonable progress 

evaluation. Using a percentage-based 

threshold enabled the State to identify 


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Federal Register / Vol. 89, No. 226 / Friday, November 22, 2024 / Rules and Regulations 92581 

34See 40 CFR 51.308(f)(2)(i), (iii); see also 

sections 2 and 2.1 of 2021 Clarifications Memo. 

35EPA’s 2019 Guidance at pp. 12–14 describes 

components of North Carolina’s AoI approach, 

including Q/d, trajectory analyses, residence time 

analyses, and source apportionment photochemical 

modeling (e.g., CAMx PSAT). 

36See, e.g., 77 FR 11858, 11869 (February 28, 

2012) for a description of North Carolina’s AoI 

approach in the first planning period. On May 24, 

2016, EPA fully approved North Carolina’s first 

period regional haze plan, effective June 23, 2016. 

See 81 FR 32652. 

37See 2019 Guidance at 9. 

38See 2019 Guidance at 13. 

the sources that contribute the largest 

amount of impact on visibility at the 

Class I areas. While it is true that using 

a one percent PSAT threshold identifies 

sources which contribute larger 

visibility impacts at the most visually 

impaired Class I areas than at the least 

visually impaired Class I areas, North 

Carolina’s targeting of sources with the 

largest visibility contributions to each 

Class I area regardless of magnitude of 

visibility impairment at a Class I area 

appears reasonable. Use of a percentagebased threshold produced a relative 

ranking of visibility impairment to 

allow the State to focus on the sources 

contributing to the largest amount of 

visibility impact at each individual 

Class I area, which has the potential to 

reduce visibility impacts the most. 

Regardless of whether a relative or 

absolute threshold is used, the number 

of sources selected depends on the 

chosen value of the threshold. North 

Carolina’s source contribution 

threshold, which identified the largest 

sources to evaluate emissions measures 

using an FFA, appears reasonable. 

Regarding the Conservation Groups’ 

assertion that the PSAT tagging process 

was unnecessary, as the AoI step 

already identified the sources that 

contributed to impairment at Class I 

areas, EPA disagrees with the premise of 

this comment. The standard is not 

whether the approach is necessary or 

required, but rather, whether the 

approach is reasonable and is 

reasonably explained.34 The two-step 

process of screening with the AoI 

analysis and then applying the more 

refined PSAT source apportionment 

modeling to sources that met the initial 

AoI screening criteria is a sound 

technical approach for identifying 

sources to evaluate for reasonable 

progress. Elements of North Carolina’s 

AoI approach are discussed in EPA’s 

2019 Guidance as a viable method to 

assess source’s visibility impacts to 

Class I areas.35 North Carolina, along 

with many of the VISTAS states, also 

relied upon the AoI initial screening 

approach in its first planning period 

haze plan.36 VISTAS used the AoI 

analysis as an initial screening step 

because it is a much simpler and less 

resource intensive approach than using 

PSAT tagging to model hundreds to 

thousands of potential sources. The AoI 

screening approach identified a smaller 

subset of sources that could undergo 

refined analysis using PSAT modeling. 

The two-step process of the screening 

AoI analysis along with using the more 

refined PSAT source apportionment 

modeling appears valid and reasonable. 

Also, as discussed above, states have 

discretion under the RHR regarding 

choice of source selection methodology. 

Comment 2.f: The Conservation 

Groups contend that EPA did not 

address the ‘‘significant flaws’’ in the 

VISTAS modeling and source selection 

process and that EPA concluded that 

North Carolina’s selection of three instate sources was reasonable because it 

enabled the identification of sources 

with the largest visibility impacts. They 

argue that this is contrary to EPA’s 

guidance which states that a source 

selection threshold that captures only a 

small portion of a state’s contribution to 

visibility impairment in Class I areas is 

more likely to be unreasonable and 

contrary to the CAA which does not 

authorize states or EPA to select only 

the largest contributors to visibility 

impairment. They assert that North 

Carolina should have used a different 

selection method with a lower 

threshold, such as a ‘‘Q/d’’ (emissions 

(Q) divided by distance to a Class I area 

(d)) with a threshold of five or lower, to 

capture the largest portion of in-state 

sources. 

Response 2.f: EPA disagrees with the 

assertion that North Carolina’s selection 

of the three largest sources contributing 

to visibility impairment at Class I areas 

is contrary to EPA’s guidance. The 

PSAT modeling performed by VISTAS 

found that the three sources selected by 

North Carolina for FFAs have the largest 

contribution to visibility impairment of 

any point sources in the State. As 

discussed in response 2.a., the PSAT 

modeling results show that the total 

cumulative contribution to visibility 

impairment on the 20 percent most 

impaired days at North Carolina’s Class 

I areas from all SO2 and NOX emitting 

sources in the State are relatively small, 

ranging from 1.91 percent for Joyce 

Kilmer to 8.66 percent for Swanquarter. 

Given state discretion in selecting 

sources to evaluate for emissions 

controls, and since the SO2 and NOX

emissions from all point sources in 

North Carolina contribute a relatively 

small amount to the visibility 

impairment at its Class I areas, the 

State’s selection of the three largest 

source contributors to visibility 

impairment appears reasonable. 

Regarding the Conservation Groups’ 

claim that the State should have 

adopted a different selection method 

(such as Q/d) with a lower threshold to 

select more sources in North Carolina 

being selected, as discussed above, a 

state is not required to evaluate all 

sources of emissions in each planning 

period. Instead, a state may reasonably 

select a set of sources for an analysis of 

control measures. Selecting a set of 

sources for analysis of control measures 

in each planning period is also 

consistent with the RHR, which sets up 

an iterative planning process and 

anticipates that a state may not need to 

analyze control measures for all its 

sources in a given SIP revision.37

Moreover, use of Q/d (which simply 

involves dividing the quantity of 

emissions by the distance to a Class I 

area) does not consider transport 

direction/pathway, dispersion and 

photochemical processes, or the 

particular days that have the most 

anthropogenic impairment due to all 

sources.38 Therefore, compared to 

photochemical modeling, using a simple 

Q/d technique, as the Conservation 

Groups suggest, would have resulted in 

a less accurate quantification of 

visibility impacts on Class I areas. As 

discussed in detail above, North 

Carolina’s reliance on VISTAS modeling 

and the State’s source selection 

methodology were well documented 

and appear reasonable. 

Comment 2.g: The Conservation 

Groups state that EPA asserts North 

Carolina’s source selection method is 

reasonable because: (1) SO2 and NOX

emissions have decreased since the first 

planning period and are projected to 

continue decreasing, (2) visibility 

conditions at in-state Class I areas are 

projected to improve and have 

improved since the baseline period, and 

(3) North Carolina sources do not 

contribute to any Class I areas above 

their respective Uniform Rate of 

Progress (URP). They argue that 

projected visibility improvement at 

North Carolina’s Class I areas and the 

fact that those areas are below their 

respective URPs are not a valid basis to 

approve the State’s flawed selection 

method. They cite to EPA guidance 

stating that the URP is not a safe harbor 

and that states cannot avoid requiring 

sources to install reasonable controls 

merely because there have been 

emissions reductions owing to ongoing 

air pollution controls since the first 

planning period or because visibility is 

projected to improve at Class I areas. 


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92582 Federal Register / Vol. 89, No. 226 / Friday, November 22, 2024 / Rules and Regulations 

39 ‘‘Clarifications Regarding Regional Haze State 

Implementation Plans for the Second 

Implementation Period.’’ https://www.epa.gov/ 

system/files/documents/2021-07/clarificationsregarding-regional-haze-state-implementationplans-for-the-second-implementation-period.pdf. 

EPA Office of Air Quality Planning and Standards, 

Research Triangle Park (July 8, 2021). 

40North Carolina considered SO2 for FFAs 

conducted in the first planning period. 

Response 2.g: EPA agrees that the 

URP is not a ‘‘safe harbor’’ to avoid 

requiring additional reasonable progress 

measures. However, factual information 

that all of the North Carolina and nearby 

Class I areas are below the URP was 

provided because being below the URP 

is relevant to whether a state needs to 

perform a ‘‘robust demonstration’’ based 

on the requirements in 40 CFR 

51.308(f)(3)(ii)(A) and (B). Therefore, a 

comparison of the URP to projected 

visibility impairment in 2028 is needed 

to inform that requirement. 

Additionally, other information about 

measured progress towards natural 

conditions can be relevant in evaluating 

the source selection process. For 

example, significant improvements in 

visibility at impacted Class I areas since 

the beginning of the second planning 

period (starting in 2018) is relevant to 

whether a state is making progress 

towards natural conditions and may 

provide information that could 

influence the selection of sources to be 

analyzed for emissions controls in the 

second planning period. Regardless of 

the visibility information listed in the 

proposed rule, EPA independently 

evaluated North Carolina’s SIP 

documentation and came to the 

conclusion that North Carolina’s source 

selection methodology and thresholds 

for this second planning period appear 

reasonable for the reasons stated earlier 

in this response. 

For the reasons discussed in 

responses 2.a through 2.g, North 

Carolina’s source selection methodology 

appears reasonable. However, the 

requirement to consider the four factors 

in establishing the LTS at 40 CFR 

51.308(f)(2) and CAA section 169A(g)(1) 

encompasses the selection of sources for 

further analysis, and as discussed above, 

EPA is disapproving the portions of the 

Haze Plan addressing 40 CFR 

51.308(f)(2) due to the inadequate 

record associated with the Domtar FFA. 

Comment 3: The Conservation Groups 

assert that EPA incorrectly endorses 

North Carolina’s decision to exclude 

consideration of NOX controls in any 

FFAs. They contend that VISTAS’ 

modeling did not accurately reflect the 

shift in the 20 percent most impaired 

days and the corresponding increase in 

the contribution of nitrate to visibility 

impairment at Southeastern Class I 

areas. They state that nitrate 

concentrations are higher on winter 

days, nitrate contributes to a substantial 

portion of light extinction at Great 

Smoky Mountains and Joyce Kilmer, 

and nitrate is the biggest contributor to 

light extinction on multiple 20 percent 

most impaired days for these areas. 

They also note EPA’s general 

expectation that states will, at a 

minimum, consider both SO2 and NOX

in this planning period, and assert that 

there are multiple sources of significant 

NOX emissions that North Carolina 

should have analyzed for NOX controls. 

Response 3: EPA disagrees with this 

comment. The RHR does not prescribe 

which visibility impairing pollutants 

must be evaluated in the FFAs. EPA’s 

2019 Guidance on page 11 states: 

‘‘When selecting sources for analysis of 

control measures, a state may focus on 

the PM species that dominate visibility 

impairment at the Class I areas affected 

by emissions from the state and then 

select only sources with emissions of 

those dominant pollutants and their 

precursors.’’ On July 8, 2021, EPA 

issued a memorandum containing 

‘‘Clarifications Regarding Regional Haze 

State Implementation Plans for the 

Second Implementation Period’’ (‘‘2021 

Clarifications Memo’’).39 Section 2.2 of 

EPA’s 2021 Clarifications Memo 

recommends that states which do not 

evaluate SO2 and NOX in both source 

selection and control evaluations show 

why such consideration of these 

pollutants would be unreasonable, 

especially if the state considered both of 

these pollutants in the first planning 

period.40

North Carolina appears to have 

followed these recommended 

approaches here. North Carolina 

considered both SO2 emissions (via 

sulfates visibility impacts) and NOX

emissions (via nitrates visibility 

impacts) in the source selection process. 

As part of the Haze Plan, DAQ 

presented the results of PSAT modeling 

conducted by VISTAS to estimate the 

projected impact of statewide SO2 and 

NOX emissions across all emissions 

sectors in 2028 on total light extinction 

for the 20 percent most impaired days 

in all Class I areas in the VISTAS 

modeling domain. The result of this 

process was that while sources were 

selected for SO2 control analysis 

determinations, no sources in North 

Carolina met the State’s nitrate source 

selection thresholds, and therefore, 

North Carolina did not select any 

sources for a NOX emissions control 

evaluation. Contrary to the Conservation 

Groups’ assertion that North Carolina 

made a ‘‘decision’’ not to consider NOX

controls in any FFA, it was North 

Carolina’s application of its source 

selection process in combination with 

data and modeling showing that SO2

and not NOX is the dominant visibility 

impairing pollutant that resulted in 

North Carolina only selecting sources 

for SO2 emissions control analyses and 

not NOX emissions control analyses. 

Additionally, in order to better 

understand the trends in PM species 

contributions to visibility impairment, 

North Carolina examined more recent 

IMPROVE monitoring data. More recent 

IMPROVE monitoring data shows that 

ammonium sulfate remains the 

dominant visibility impairing pollutant 

at North Carolina’s Class I areas as 

discussed in section 2.5.2 of the Haze 

Plan (particularly figures 2–7 through 2– 

10 for the 2009–2013 period) and in 

section 2.6.2 (particularly figures 2–13 

through 2–16 for the 2014–2018 period). 

The 2015–2019 IMPROVE monitoring 

data (the most recent data available at 

the time) cited within the Haze Plan 

(figures 10–1, 10–2, and 10–3) identifies 

the relative contributions of PM species 

contributing to the total visibility 

impairment at the North Carolina Class 

I areas, which are shown in table 2, 

below. In spite of increased nitrate 

contributions on the 20 percent most 

impaired days (as the Conservation 

Groups note, often on winter days), as 

indicated in that table, ammonium 

nitrate contributions to regional haze at 

the State’s Class I areas remain 

relatively low at 8 to 17 percent of the 

total visibility impairment as compared 

to ammonium sulfate at 50 to 58 

percent. 


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Federal Register / Vol. 89, No. 226 / Friday, November 22, 2024 / Rules and Regulations 92583 

41See Haze Plan, section 2 (particularly figures 2– 

13 through 2–18), section 7 (particularly figures 7– 

25 through 7–31), and section 10 (particularly 

figures 10–1 through 10–7); 89 FR 67353–54. 

42The Conservation Groups’ letter identifies five 

Duke Energy EGUs on pages iv and 46 and 

identifies four Duke Energy EGUs in the Table of 

Contents on page v and in sections III.D.1.i–iv of the 

letter. The five Duke Energy EGUs listed on pages 

iv and 46 that the Conservation Groups recommend 

to be evaluated for emissions controls are: DEC— 

Belews Creek, DEC—Cliffside, DEC—Marshall, 

DEP—Roxboro, and DEP—Mayo. Sections III.D.1.i– 

iv do not include recommendations regarding 

improved control efficiencies specific to DEP-Mayo. 

43The Conservation Groups provide the following 

information for these four Duke Energy EGUs: 

DEC—Belews Creek contributes to up to 2.01 

percent of the sulfate plus nitrate impairment at 

Linville Gorge and up to 1.56 percent of the sulfate 

plus nitrate impairment at Shining Rock; DEC— 

Cliffside contributes to up to 1.85 percent of the 

sulfate plus nitrate impairment at Shining Rock and 

2.49 percent at Linville Gorge; DEC—Marshall 

contributes to up to 6.73 percent of the sulfate plus 

nitrate impairment at Linville Gorge and up to 2.68 

percent of the sulfate plus nitrate impairment at 

Shining Rock; and DEP—Roxboro contributes to up 

to 2.23 percent of the sulfate plus nitrate 

impairment at Swanquarter. 

TABLE 2—2015–2019 SPECIATED IMPROVE MONITORING DATA FOR NORTH CAROLINA’S CLASS I AREAS

Ammonium 

sulfate 

(%) 

Ammonium 

nitrate 

(%) 

Organic 

carbon 

(%) 

Coarse 

mass 

(%) 

Elemental 

carbon 

(%) 

Fine 

sea salt 

(%) 

Fine 

soils 

(%) 

Great Smoky Mountains .................................. 54 17 17 5 6 1 1 

Joyce Kilmer .................................................... 54 17 17 5 6 1 1 

Linville Gorge ................................................... 57 8 22 5 7 0 1 

Shining Rock .................................................... 58 10 19 5 5 1 1 

Swanquarter ..................................................... 50 17 17 7 5 3 1 

Additionally, in figure 10–7 of the 

Haze Plan, North Carolina provides a 

comparison of the sulfate and nitrate 

five-year averages for the 2009–2013 

and 2015–2019 periods for all the Class 

I areas in the VISTAS region. North 

Carolina’s conclusion that although 

nitrate contributions have increased for 

some Class I areas, sulfate remains the 

dominant visibility impairing species 

through 2019, appears reasonable. 

Furthermore, in tables 7–20 through 

7–24 of the Haze Plan, the State 

provided a calculation of the sulfate and 

nitrate EWRT used in the AoI analysis 

for Great Smoky Mountains, Joyce 

Kilmer, Linville Gorge, Shining Rock, 

and Swanquarter for the 20 percent 

most impaired days, demonstrating that 

the sulfate EWRT are significantly 

higher than the nitrate EWRT. This 

further supports the importance of 

focusing on SO2 emissions reductions 

for this planning period. The State’s 

rationale for focusing on SO2 controls in 

the FFAs is summarized in North 

Carolina’s SIP submittal and the 

NPRM.41

With respect to the Conservation 

Groups’ assertion that nitrate is the 

biggest contributor to light extinction on 

multiple of the 20 percent of most 

impaired days for these North Carolina 

Class I areas during the 2014–2018 

period (especially on winter days), as 

described above, the average nitrate 

contribution across the 20 percent most 

impaired days is still relatively small. 

Thus, while nitrate impairment may be 

relatively high on a particular day, the 

data that states are required to use for 

regional haze as specified in 40 CFR 

51.301 and 40 CFR 51.308(f)(1) shows 

ammonium nitrate only contributes 8 to 

17 percent of the total visibility 

impairment (during the 2015–2019 

period). 

North Carolina’s justification for not 

evaluating sources selected for SO2

emission control analyses for a separate 

NOX emission control analysis appears 

reasonable for this planning period. The 

trends in PM species’ contributions to 

visibility impairment will continue to 

be evaluated in future planning periods. 

If the data warrants consideration of 

NOX controls in future planning 

periods, EPA expects that North 

Carolina will address potential NOX

controls in future regional haze SIP 

revisions. However, the requirement to 

consider the four factors in establishing 

the LTS at 40 CFR 51.308(f)(2) and CAA 

section 169A(g)(1) encompasses 

decisions regarding the visibility 

impairing pollutants evaluated in the 

FFAs, and as discussed above, EPA is 

disapproving the portions of the Haze 

Plan addressing 40 CFR 51.308(f)(2) due 

to the inadequate record associated with 

the Domtar FFA. 

Comment 4: The Conservation Groups 

assert that, to correct errors in the 

source selection method, EPA must 

require North Carolina to assess 

additional EGU sources identified by 

NPS and NPCA with emissions that 

likely contribute to visibility 

impairment at Class I areas. The 

Conservation Groups argue that the 

State arbitrarily refused to consider costeffective control efficiency 

improvements at each Duke Energy EGU 

and identify specific concerns for DEC— 

Belews Creek, DEC—Cliffside, DEC— 

Marshall, and DEP—Roxboro.42 They 

contend that EPA must disapprove the 

State’s reliance on unenforceable 

emission reductions to avoid 

conducting FFAs at these EGUs, and 

that EPA must disapprove the State’s 

refusal to conduct FFAs for sources that 

the State’s analysis shows are 

reasonably anticipated to contribute to 

visibility impairment. These specific 

arguments are addressed in comments 

4.a through 4.g, below. 

Comment 4.a: The Conservation 

Groups contend that states must 

consider recent actual and projected 

emission rates to determine if a source 

could reasonably attain a lower rate 

with existing measures. For DEC— 

Belews Creek, DEC—Cliffside, DEC— 

Marshall, and DEP—Roxboro, the 

Conservation Groups assert errors in 

North Carolina’s analysis of potential 

emission reductions for NOX and SO2

and that, in each instance, EPA must 

disapprove the State’s analysis, conduct 

its own FFA, and require cost effective 

control upgrades in a FIP.43 The alleged 

errors for these four facilities are 

addressed in comments 4.b through 4.e, 

below. 

Response 4.a: As explained in 

response 2.a and in the NPRM (89 FR 

67346), the RHR does not require states 

to select and consider controls for all 

sources, all source categories, or any or 

all sources in a particular source 

category. Nor does the RHR expressly 

specify criteria for minimum source 

selection thresholds. States have 

discretion to choose reasonable source 

selection criteria, and sources that meet 

the state’s criteria are selected for an 

evaluation of potential control options 

for specific visibility impairing 

pollutants by applying the four statutory 

factors in CAA section 169A(g)(1), 

which is referred to as an FFA. 

The Conservation Groups contend 

that DEC—Marshall exceeded the AoI 

threshold set by North Carolina, but 

EPA notes that no Duke Energy EGU 

exceeded the State’s PSAT threshold at 

any Class I area. Therefore, North 

Carolina did not evaluate any Duke 

Energy EGU for potential emissions 


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92584 Federal Register / Vol. 89, No. 226 / Friday, November 22, 2024 / Rules and Regulations 

44Table 7–29 of the Haze Plan lists facilities that 

met North Carolina’s AoI threshold and thus were 

selected by the State for PSAT tagging. Tables 7– 

30 through 7–35 provide PSAT results for the North 

Carolina Class I areas. 

45See 2019 Guidance at p. 19 (‘‘For example, it 

may be difficult to show reasonableness of a 

threshold set so high that an uncontrolled or lightly 

controlled source that is one of the largest 

contributors to anthropogenic light extinction at a 

Class I area is excluded.’’). 

46See Haze Plan at p. 251. 

47Between the years 2017–2022, the calculated 

annual FGD SO2 control efficiencies for DEP—Mayo 

Unit 1A were between 96.3 and 97.9 percent. 

48The MATS rule is located at 40 CFR part 63, 

subpart UUUUU. 

49See North Carolina Duke Energy scrubber 

efficiency data file that is included in the docket for 

this action. See also 89 FR 67359; 2019 Guidance 

at 23. 

50Between 2017 to 2022, the yearly average FGD 

SO2 control efficiencies for Unit 1 ranged from 94.7 

to 96.2 percent, Unit 2 ranged from 93.8 to 96.1 

percent, Unit 3 ranged from 95.2 to 97.1 percent, 

and Unit 4 ranged from 96.7 to 97.9 percent. See 

North Carolina Duke Energy scrubber efficiency 

data file that is included in the docket for this 

action. 

controls. This approach is consistent 

with the State’s source selection results 

summarized in tables 7–30 through 7– 

35,44 and North Carolina’s decision not 

to assess Duke Energy EGUs for control 

efficiency improvements because they 

did not meet the State’s source selection 

criteria appears reasonable. 

As described in the 2019 Guidance,45

North Carolina completed an additional 

reasonableness check on their source 

selection process by examining the 

unselected sources to see if there were 

any ‘‘uncontrolled or lightly controlled 

facilities that were large contributors to 

anthropogenic light extinction,’’ and 

found none.46 In the NPRM (89 FR 

67359), EPA documented an analysis 

that further examined the Duke Energy 

sources to verify North Carolina’s claim 

that there were no uncontrolled or 

lightly controlled sources that were not 

selected. EPA evaluated the existing SO2

controls at DEC—Belews Creek, DEC— 

Cliffside, DEC—Marshall, DEP—Mayo, 

and DEP—Roxboro. EPA analyzed 

whether these EGUs are well controlled 

for SO2 and whether any cost-effective 

new emissions reduction measures for 

SO2 would have likely resulted from a 

FFA had these sources met the State’s 

source selection criteria.47 Based on that 

analysis, it appears reasonable to 

assume that a FFA would likely result 

in the conclusion that no further SO2

emissions controls are needed for these 

sources. All of these EGUs are subject to 

the Mercury and Air Toxics Standards 

(MATS) rule 48 alternative SO2 emission 

limit of 0.2 pound (lb)/million British 

thermal units (MMBtu) and are 

equipped with wet flue gas 

desulfurization (WFGD) that routinely 

achieve a high SO2 control effectiveness 

(approximately 93.8–99.2 percent).49

EPA did not evaluate NOX controls for 

these EGUs because North Carolina’s 

conclusion that ammonium sulfate 

continues to be the dominant visibility 

impairing pollutant at North Carolina’s 

Class I areas appears reasonable. See 

section IV.C.2.a of the NPRM and 

response 3. 

Comment 4.b: The Conservation 

Groups argue that North Carolina’s 

analysis of potential emission 

reductions for DEC—Marshall suffer 

from the following errors regarding SO2: 

(1) the wet scrubbers are operated 

erratically; (2) the units have the ability 

to continuously operate well below 0.10 

lb/MMBtu for SO2; (3) ‘‘EPA has 

concluded that underperforming wet 

scrubbers should be evaluated at 98 

percent control (with a floor of 0.04 lb/ 

MMBtu), and 95 percent control (with a 

floor of 0.06 lb/MMBtu) for dry 

scrubbers;’’ (4) ‘‘even lower limits can 

be achieved;’’ and (5) ‘‘Without any 

capital upgrade cost (and likely minimal 

operating and maintenance costs) the 

DEC-Marshall units are likely quite 

capable of much better SO2 and NOX

removal efficiencies that could likely be 

achieved with cost-effective upgrades.’’ 

They also argue that North Carolina’s 

analysis of potential NOX emission 

reductions suffer from the following 

errors: (1) ‘‘Units 1, 2, and 4 are 

equipped with selective non-catalytic 

reduction (SNCR) systems that have 

achieved lower NOX emission levels of 

approximately 0.20 lb/MMBtu, ‘with 

some months significantly below that 

level;’ ’’ (2) the selective catalytic 

reduction (SCR) system for Unit 3 is 

‘‘operated very erratically, but has 

demonstrated the ability from 2010– 

2011 to consistently operate below 0.05 

lbs/MMBtu;’’ and (3) ‘‘Without any 

capital upgrade cost (and likely minimal 

operating and maintenance costs) the 

DEC—Marshall units are quite capable 

of much better NOX removal efficiencies 

with likely cost-effective upgrades. 

Response 4.b: Regarding potential 

NOX control upgrades at DEC— 

Marshall, North Carolina’s decision to 

focus on SO2 emission controls in the 

second planning period appears 

reasonable given the documented 

dominance of sulfate contributions to 

visibility impairment at North 

Carolina’s Class I areas. See section 

IV.C.2.a of the NPRM and response 3. 

Thus, it appears reasonable to conclude 

that even if DEC—Marshall had met the 

State’s source selection criteria, no NOX

emissions control analyses would be 

necessary for reasonable progress during 

this planning period. Additionally, 

North Carolina did not select this 

facility, and therefore, no FFA 

information is available. However, 

EPA’s analysis confirms that the units 

are not uncontrolled or lightly 

controlled, are subject to the MATS rule 

alternative SO2 emission limit of 0.2 lb/ 

MMBtu, and are equipped with WFGD 

that routinely achieve a high SO2

control effectiveness (approximately 

93.8 to 97.9 percent).50

Comment 4.c: The Conservation 

Groups argue that North Carolina’s 

analysis of potential emission 

reductions at DEC—Belews Creek suffer 

from the following errors regarding SO2: 

(1) the wet scrubbers ‘‘are 

underperforming, with emission rates, 

at times, spiking above 0.30 lb/MMBtu;’’ 

(2) the scrubbers ‘‘have demonstrated 

the capability to consistently control 

SO2 to 0.05 lbs/MMBtu or better on a 

monthly average basis for both units;’’ 

(3) ‘‘[s]imply increasing the amount of 

reagent used would be very costeffective, require little or no capital 

investments, and would likely achieve 

much lower emissions;’’ and (4) the 

‘‘assumption that SO2 emissions will be 

reduced from 4,946 to 1,385 tons 

annually is not supported in the record, 

and not based on any enforceable 

requirement.’’ They also argue that 

North Carolina’s analysis of potential 

emission reductions suffer from the 

following errors regarding NOX: (1) the 

‘‘2028 NOX emission projections for 

Belews Creek are significantly less than 

the facility has emitted in recent years, 

yet there are no enforceable emission 

limitations in the SIP Revision that 

would ensure those 2028 estimates;’’ (2) 

the ‘‘SCR systems perform erratically, 

with emissions above 0.40 lb/MMBtu at 

times;’’ (3) ‘‘Belews Creek could likely 

achieve NOX emission rates of 0.05 lbs/ 

MMBtu or better on a consistent basis 

with better catalyst and absorber 

management;’’ and (4) ‘‘[s]imple 

upgrades to the SCR system would 

likely be cost-effective.’’ 

Response 4.c: Regarding potential 

NOX control upgrades at DEC—Belews 

Creek, North Carolina’s decision to 

focus on SO2 emission controls in the 

second planning period appears 

reasonable given the documented 

dominance of sulfate contributions to 

visibility impairment at North 

Carolina’s Class I areas. See section 

IV.C.2.a of the NPRM and response 3. 

Thus, it appears reasonable to conclude 

that even if DEC—Belews Creek had met 

the State’s source selection criteria, no 

NOX emissions control analyses would 

be warranted. 

Regarding the original and revised 

2028 SO2 emissions projections of 4,946 

tpy and 1,385 tpy, respectively, for 


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51See https://www.epa.gov/air-emissionsinventories/eastern-regional-technical-advisorycommittee-ertac-electricity. 

52Between 2017 to 2022, the yearly average FGD 

SO2 control efficiencies for Unit 1 ranged from 94.1 

to 96.5 percent and Unit 2 ranged from 95.0 to 96.2 

percent. See North Carolina Duke Energy scrubber 

efficiency data file that is included in the docket for 

this action. 

53Between 2017 to 2022, the yearly average FGD 

SO2 control efficiencies for Unit 1 ranged from 95.9 

to 97.1 percent, Unit 2 ranged from 94.3 to 96.6 

percent, Unit 3A ranged from 98.2 to 98.8 percent, 

and Unit 4A ranged from 97.1 to 98.3 percent. See 

North Carolina Duke Energy scrubber efficiency 

data file that is included in the docket for this 

action. 

54Between 2017 to 2022, the yearly average FGD 

SO2 control efficiencies for Unit 5 ranged from 96.2 

to 98.6 percent and Unit 6 ranged from 98.0 to 99.2 

Continued 

DEC—Belews Creek listed in table 7–41 

of the Haze Plan, as explained in 

responses 1 and 2.c, North Carolina 

used the best assumptions available at 

the time of SIP development to project 

the 2011 base year emissions out to 

2028 for sources in the State, including 

DEC—Belews Creek. North Carolina did 

document its 2028 point source 

emissions projection methodology in 

appendix B–3 of the Haze Plan. Table 9 

in appendix B–3 shows that the 1,385 

tpy 2028 projected SO2 value in table 7– 

41 of the plan is from a blend of two 

versions (2.7 and 16.0) of the Eastern 

Regional Technical Advisory Committee 

(ERTAC) EGU Emissions Projection 

Tool 51 that was used to create the 

VISTAS 2028elv5 emissions inventory. 

As stated in response 2.c, North 

Carolina’s and EPA’s projected 2028 

emissions projections, summarized in 

appendix B–3 of the Haze Plan, are 

similar. Therefore, North Carolina’s 

2028 SO2 emissions projections for 

DEC—Belews Creek appear to be 

reasonable estimates. 

Additionally, North Carolina did not 

select this facility, and therefore, no 

FFA information is available. However, 

EPA’s analysis confirms that the units 

are not uncontrolled or lightly 

controlled, are subject to the MATS rule 

alternative SO2 emission limit of 0.2 lb/ 

MMBtu, and are equipped with WFGD 

that routinely achieve a high SO2

control effectiveness (approximately 

94.1 to 96.5 percent).52

Comment 4.d: The Conservation 

Groups argue that North Carolina’s 

analysis of potential emission 

reductions for DEP—Roxboro suffer 

from the following errors regarding SO2: 

(1) the ‘‘projections for 2028 SO2 are not 

based on historical data, but instead rely 

on unenforceable, predicted emission 

reductions, from 6,665 in 2020, to 2,258 

tons in 2028;’’ (2) the wet scrubbers ‘‘are 

underperforming with emissions as high 

as 0.35 lb/MMBtu;’’ (3) the scrubbers 

‘‘have ‘demonstrated the capability to 

consistently control SO2 to 

approximately 0.075 lb/MMBtu or better 

on a monthly average;’ ’’ and (4) there 

are ‘‘likely very cost-effective scrubber 

upgrades available.’’ They also argue 

that North Carolina’s analysis of 

potential emission reductions suffer 

from the following errors regarding 

NOX: (1) the ‘‘projections for 2028 NOX

emissions are not based on historical 

data, but instead rely on unenforceable, 

predicted emission reductions;’’ (2) the 

‘‘SCR systems perform erratically, with 

emissions sometimes spiking to nearly 

0.5 lb/MMBtu, which is far worse than 

the rates commonly achievable and 

required of well-functioning SCR 

systems;’’ (3) the ‘‘SCR systems have ‘all 

have demonstrated the ability to 

continuously operate at approximately 

0.10 lbs/MMBtu;’ ’’ and (4) there are 

‘‘likely very cost-effective control 

upgrades available.’’ 

Response 4.d: Regarding potential 

NOX control upgrades and SCR 

performance at DEP—Roxboro, North 

Carolina’s decision to focus on SO2

emission controls in the second 

planning period appears reasonable 

given the documented dominance of 

sulfate contributions to visibility 

impairment at North Carolina’s Class I 

areas. See section IV.C.2.a of the NPRM 

and response 3. Thus, it appears 

reasonable to conclude that even if 

DEP—Roxboro had met the State’s 

source selection criteria, no NOX

emissions control analyses would be 

warranted. 

Regarding the original and revised 

2028 SO2 emissions projections of 6,665 

tpy and 2,258 tpy, respectively, for 

DEP—Roxboro listed in table 7–41 of 

the Haze Plan, as explained in responses 

1 and 2.c, North Carolina used the best 

assumptions available at the time of SIP 

development to project the 2011 base 

year emissions out to 2028 for sources 

in the State, including DEP—Roxboro. 

North Carolina did document its 2028 

point source emissions projection 

methodology in appendix B–3 of the 

Haze Plan. Table 9 in appendix B–3 

shows a 2028 projection of 6,666 tpy 

SO2 for DEP—Roxboro is derived from 

ERTAC2.7 (2011 base year) whereas the 

VISTAS 2028 elv5 uses a 2,258 tpy SO2

2028 emissions projection. As stated in 

response 2.c, North Carolina’s and 

EPA’s projected 2028 emissions 

projections, summarized in appendix B– 

3 of the Haze Plan, are similar. 

Therefore, North Carolina’s 2028 SO2

emissions projections for DEP—Roxboro 

appear to be reasonable estimates. 

Additionally, North Carolina did not 

select this facility, and therefore, no 

FFA information is available. However, 

EPA’s analysis confirms that the units 

are not uncontrolled or lightly 

controlled, are subject to the MATS rule 

alternative SO2 emission limit of 0.2 lb/ 

MMBtu, and are equipped with WFGD 

that routinely achieve a high SO2

control effectiveness (approximately 

94.3 to 98.8 percent).53

Comment 4.e: The Conservation 

Groups argue that North Carolina’s 

analysis of potential emission 

reductions from DEC—Cliffside suffer 

from the following errors regarding SO2: 

(1) the ‘‘scrubber performance is erratic, 

with SO2 spikes at Unit 5 periodically 

exceeding 0.35 lb/MMBtu;’’ (2) 

‘‘Nevertheless, each of the scrubbers 

have demonstrated an ability to 

consistently achieve SO2 emissions of 

0.04 lb/MMBtu;’’ and (3) ‘‘ ‘[V]ery costeffective controls are available for these 

units for likely just the increase in 

reagent,’ yet the State failed to even 

consider such upgrades.’’ They also 

argue that North Carolina’s analysis of 

potential emission reductions suffer 

from the following errors regarding 

NOX: (1) the ‘‘SCR systems are similarly 

irregular, with spikes at Unit 5 

exceeding 0.30 lb/MMBtu NOX;’’ (2) the 

‘‘SCR systems have demonstrated an 

ability to consistently achieve NOX

emissions of 0.05 lb/MMBtu;’’ and (3) 

‘‘Cost-effective improvements, such as 

optimizing the catalyst controls would 

likely be very cost-effective, but the 

State failed to even run such cost 

calculation.’’ 

Response 4.e: Regarding potential 

NOX control upgrades and SCR 

performance at DEC—Cliffside, North 

Carolina’s decision to focus on SO2

emission controls in the second 

planning period appears reasonable 

given the documented dominance of 

sulfate contributions to visibility 

impairment at North Carolina’s Class I 

areas. See section IV.C.2.a of the NPRM 

and response 3. Thus, it appears 

reasonable to conclude that even if 

DEC—Cliffside had met the State’s 

source selection criteria, no NOX

emissions control analyses would be 

warranted. Additionally, North Carolina 

did not select this facility, and therefore, 

no FFA information is available. 

However, EPA’s analysis confirms that 

the units are not uncontrolled or lightly 

controlled, are subject to the MATS rule 

alternative SO2 emission limit of 0.2 lb/ 

MMBtu, and are equipped with WFGD 

that routinely achieve a high SO2

control effectiveness (96.2 to 99.2 

percent).54


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percent. See North Carolina Duke Energy scrubber 

efficiency data file that is included in the docket for 

this action. 

55See 2019 Guidance at p. 17 (‘‘Generally, we 

recommend that states use estimates of 2028 

emissions (resolved by day and hour, as 

appropriate) to estimate visibility impacts (or 

related surrogates) when selecting sources, rather 

than values of recent year emissions.’’). 

56 ‘‘The long-term strategy must include the 

enforceable emissions limitations, compliance 

schedules, and other measures that are necessary to 

make reasonable progress, as determined pursuant 

to (f)(2)(i) through (iv).’’ See 40 CFR 51.308(f)(2). 

Measures necessary to make reasonable progress 

must be incorporated into the SIP and LTS. The 

CAA also requires that States incorporate these 

measures into their SIPs. See 42 U.S.C. 7491(b)(2), 

(b)(2)(B). The State may also elect to include 

additional measures that address regional haze, 

beyond those identified as necessary to make 

reasonable progress, to strengthen the SIP. 

57See section 7.7.3.2, ‘‘Facilities Not Selected for 

PSAT Modeling,’’ of the Haze Plan. 

Comment 4.f: The Conservation 

Groups assert that EPA must disapprove 

North Carolina’s reliance on 

unenforceable, hypothetical emission 

reductions for the Duke Energy EGUs to 

avoid conducting control analyses, to 

demonstrate reasonable progress, and to 

achieve the State’s reasonable progress 

goals (RPGs). They note that the CAA 

and RHR require the Haze Plan to 

include enforceable limitations and 

other control measures to meet the RPGs 

for each Class I area and that EPA has 

made it clear that, to the extent that a 

state declines to evaluate pollution 

controls to reduce haze for any source 

based on that source’s planned decline 

in utilization or reductions in 

emissions, it must incorporate those 

operating parameters or assumptions as 

enforceable limitations into the SIP. 

The Conservation Groups disagree 

with North Carolina’s statement that the 

‘‘obligation to make reductions 

permanent and enforceable does not 

extend to any control or emissions 

reduction determination outside of the 

reasonable progress/four-factor 

analysis.’’ The Conservation Groups 

state that the requirement to ensure that 

emission reductions are enforceable 

stems from the CAA and the RHR itself 

and quote the 2021 Clarification Memo 

for the proposition that existing and 

‘‘on-the-way’’ measures must be 

included in the SIP if they are necessary 

for reasonable progress. The 

Conservation Groups also contend that 

neither the State, EPA, nor the public 

can verify that reasonable progress will 

be made if the State’s assumed pollution 

reductions to achieve reasonable 

progress are not enforceable. 

Response 4.f: EPA disagrees with the 

Conservation Groups assertion that 

North Carolina’s analysis 

inappropriately relied on unenforceable 

emission reductions to avoid 

conducting control analyses for the 

DEC—Belews Creek, DEC—Cliffside, 

DEC—Marshall, DEP—Roxboro, and 

DEP—Mayo. North Carolina followed 

the recommendations in the 2019 

Guidance to select sources based on 

2028 emissions projections.55 As 

explained in the NPRM, the State 

(through VISTAS) developed a 2011 

statewide base year emissions inventory 

which was used to project emissions out 

to 2028, the end of the second planning 

period. See 89 FR 67356. The accuracy 

of the 2028 emissions projections for 

these five Duke Energy EGUs is 

discussed in response 2.c. North 

Carolina relied on sophisticated PSAT 

modeling to identify visibility impacts 

of the State’s AoI sources to any Class 

I areas, and no Duke Energy EGU met 

the State’s PSAT threshold for sulfate or 

nitrate. Because none of these Duke 

Energy EGUs met the State’s source 

selection criteria, North Carolina’s 

decision to not consider whether control 

measures at these sources are necessary 

for reasonable progress appears 

reasonable. With respect to arguments 

that the RPGs must be developed based 

on enforceable measures, the RPGs 

reflect a state’s best estimate of visibility 

conditions in the Class I area at the end 

of planning period (e.g., 2028 for the 

second planning period). Under the 

RHR, RPGs should account for all 

measures included in a state’s LTS, 

other states’ LTSs, as well as the 

implementation of other CAA 

requirements, including non-SIP based 

requirements. The measures underlying 

the RPGs—except for the LTS measures 

found necessary for reasonable 

progress—are not required to be adopted 

into the SIP. 

Regarding the statement that ‘‘[t]he 

RHR provides that the measures 

necessary to the State’s long-term 

strategy for ensuring reasonable progress 

and its reasonable progress goals must 

be ‘as a result of [ ] enforceable 

emissions limitations . . .’ ’’ EPA 

agrees.56 As explained in the NPRM (89 

FR 67347), 40 CFR 51.308(f)(2)(i) 

requires states to determine the 

emission reduction measures for sources 

that are necessary to make reasonable 

progress by considering the four factors. 

Pursuant to 40 CFR 51.308(f)(2), 

measures that are determined necessary 

to make reasonable progress toward the 

national visibility goal must be included 

in a state’s LTS and in its SIP. As noted 

above, however, the Duke Energy EGUs 

did not meet the State’s source selection 

criteria, and therefore, North Carolina’s 

decision to not to evaluate them for 

controls appears reasonable. 

Regarding the Conservation Groups’ 

references to the 2021 Clarification 

Memo regarding in-place and on-theway measures, these references relate to 

measures necessary for reasonable 

progress. They do not apply to the Duke 

Energy EGUs because these units did 

not meet the State’s source selection 

criteria, and therefore, they do not have 

measures necessary for reasonable 

progress. As a result, no measures must 

be adopted into the SIP for these EGUs. 

North Carolina provided a summary 

in table 7–43 of the SO2 and NOX

controls, operating status, and 

applicable Federal rules for Duke 

Energy facilities with coal units.57 There 

is no indication in the Haze Plan that 

the State is relying upon these existing 

measures listed in table 7–43 as existing 

effective controls pursuant to the 2019 

Guidance at pages 22–25. In fact, North 

Carolina states on page 254 of its Haze 

Plan that ‘‘Based on current controlled 

and projected 2028 emissions, the 

NCDAQ concluded that it was not 

necessary to request that the facilities 

complete a reasonable progress/fourfactor analysis to demonstrate progress 

toward achieving the modeled 2028 

RPGs discussed in Section 8 of this 

SIP.’’ 

Comment 4.g: The Conservation 

Groups contend that North Carolina 

arbitrarily and unlawfully refused to 

conduct FFAs for the Duke Energy EGUs 

despite their undisputed contribution to 

visibility impairment in numerous Class 

I areas. They provide the following 

arguments to support this contention. 

First, the text of the CAA and the RHR 

require the State to evaluate the four 

statutory factors for any source 

reasonably anticipated to cause or 

contribute to any visibility impairment 

at any Class I area. The Conservation 

Groups state that North Carolina 

improperly rewrites the statute and 

regulation to require consideration of 

the four factors only when a source 

‘‘significantly contributes’’ to visibility 

impairment. Second, the structure of the 

CAA makes clear the requirement to 

implement emission reductions to 

ensure reasonable progress is not 

contingent on whether a source 

significantly contributes to visibility 

impairment. They note that Congress 

expressly uses the modifier 

‘‘significant’’ in numerous sections of 

the CAA and argue that the modifier is 

conspicuously absent from CAA section 

169A. Third, the purpose of the CAA’s 

visibility provisions to reduce and 

ultimately eliminate ‘‘any impairment of 

visibility’’ makes clear that Congress 

‘‘intended for the term ‘contributes’ as 

used in 7491(b)(2) to encompass smaller 


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58See 2019 Guidance at 10. 

59See id. at 19. 

60See 40 CFR 51.102, 51.103, and 40 CFR part 51, 

appendix V, 2.1. 

impacts than would be required to 

regulate only those sources that 

contribute ‘significantly.’ ’’ They claim 

that North Carolina ‘‘effectively rewrites 

those provisions of the Act and requires 

only the evaluation of emissions that it 

deems significant or large enough.’’ The 

Conservation Groups acknowledge that 

there is no bright line test for assessing 

contribution under the RHR, but state 

that EPA has ‘‘made clear that a state’s 

reasonable progress analysis must 

consider a meaningful set of sources and 

controls that impact visibility’’ and that 

if a state fails to do so, EPA must 

disapprove the SIP revision and issue a 

FIP. 

Response 4.g: EPA agrees that CAA 

section 169A and the RHR do not use 

the phrases ‘‘significant contribution’’ or 

‘‘significantly contribute’’ when 

discussing the four factors. The CAA 

and RHR do not explicitly list factors 

that a state must or may not consider 

when selecting the sources for which it 

will determine what control measures 

are necessary to make reasonable 

progress.58 The appropriate threshold 

for selecting sources may reasonably 

differ across states and Class I areas due 

to varying circumstances. In setting a 

threshold, a state may consider the 

number of emissions sources affecting 

the Class I areas at issue, the magnitude 

of the individual sources’ impacts, and 

the amount of anthropogenic visibility 

impairment at the Class I areas.59 As 

discussed in response 2.a, North 

Carolina considered the magnitude of 

the individual sources’ impacts at Class 

I areas using AoI screening and PSAT 

modeling which appears to be a 

reasonable approach to identifying 

sources in the State that are reasonably 

anticipated to cause or contribute to 

visibility impairment in any Class I area. 

Comment 5: The Conservation Groups 

assert that EPA must disapprove North 

Carolina’s SIP revision because the 

public was not given the opportunity to 

comment on VISTAS modeling and 

other work products when they were 

being developed. Instead, they contend 

that North Carolina presented the 

VISTAS work products in its draft SIP 

as final products that are not subject to 

change, regardless of public input. The 

Conservation Groups also assert that a 

state must make its regional haze SIP 

and the associated technical work 

products from the RPOs that support the 

SIP available for public notice and 

comment. Additionally, they contend 

that when RPOs, like VISTAS, receive 

funding from EPA to develop work 

products that states rely on when 

developing their regional haze SIPs, 

EPA must use its grant oversight 

authority to ensure the RPOs’ work 

products comply with all statutory and 

regulatory requirements. 

Response 5: EPA agrees that technical 

information supporting North Carolina’s 

regional haze plan should be available 

for public review and comment but 

disagrees that the public was not given 

an opportunity to comment on relevant 

VISTAS work products relied upon by 

North Carolina for the Haze Plan. On 

August 30, 2021, the State opened the 

public comment period on its proposed 

Haze Plan through October 15, 2021, 

and on October 6, 2021, it held a public 

hearing on the Haze Plan. This proposed 

Haze Plan included VISTAS work 

products (located in appendices A–E) 

that the State relied upon in developing 

its plan. 

North Carolina exceeded the 

minimum public notice and comment 

requirements for SIP revisions which 

are set forth in 40 CFR part 51.60 The 

CAA does not require states to engage in 

public notice and comment while they 

are developing modeling and other 

technical work products for use in 

preparing SIP revisions. 

Furthermore, the RHR allows states to 

rely on technical analyses developed by 

RPOs when that analysis is approved by 

all state participants, does not require 

RPOs to provide notice and comment 

for its work products, and does not 

require states to provide notice and 

comment during the technical 

development of their regional haze SIPs. 

See 40 CFR 51.308(f)(2)(iii). The RHR 

does require states to document the 

technical basis, including modeling, 

monitoring, cost, engineering, and 

emissions information, on which the 

State relied to determine the emission 

reduction measures that are necessary to 

make reasonable progress in each Class 

I area it affects. See id. As discussed 

above, the Haze Plan includes the 

VISTAS work products relied upon by 

the State. 

EPA also disagrees with the comment 

that North Carolina ‘‘communicated in 

its Haze Plan that the VISTAS products 

on which the State relied for source 

selection and in setting its reasonable 

progress goals were complete and done’’ 

and presented the VISTAS work 

products as ‘‘final products that would 

not be changed, regardless of any public 

input.’’ The Conservation Groups did 

not cite to any such express language in 

the Haze Plan. To the extent that North 

Carolina relied on the VISTAS’ work 

products to satisfy regional haze 

requirements, those work products were 

subject to public notice and comment at 

the state level; EPA evaluated the 

relevant aspects of the VISTAS work 

products as they relate to the review of 

the State’s Haze Plan; they were subject 

to notice and comment as part of EPA’s 

proposed rulemaking, and EPA would 

not fully approve a SIP revision that it 

determined does not meet regional haze 

requirements due to flawed work 

products. 

With respect to the comment 

concerning grant obligations and ‘‘grant 

oversight authority,’’ EPA has not 

directly provided any grant money to 

VISTAS for the second planning period. 

Regardless, EPA disagrees with the 

Conservation Groups’ comments 

regarding the VISTAS work products for 

the reasons discussed in this notice of 

final rulemaking. 

Comment 6: The Conservation Groups 

assert that EPA shirks its duty to review 

North Carolina’s source-specific FFAs. 

They state that EPA proposes to ‘‘rubber 

stamp’’ the SIP submission without 

engaging in any meaningful and 

independent analysis of North 

Carolina’s FFAs to ensure they comply 

with the CAA and the RHR. Moreover, 

they assert that ‘‘[d]espite EPA’s stated 

expectations for this planning period, 

North Carolina does not require any of 

the sources to adopt additional control 

measures to make reasonable progress’’ 

and that EPA accepts North Carolina’s 

decision to ignore ‘‘readily available, 

feasible, and cost-effective controls’’ 

which violates the CAA and RHR. The 

Conservation Groups’ specific 

comments on the FFAs for Domtar, PCS, 

and BRPP are addressed in comments 7 

through 9, below. 

Response 6: For various reasons, EPA 

disagrees with the Conservation Groups’ 

contentions. EPA’s partial approval and 

partial disapproval of the Haze Plan is 

a proper exercise of EPA’s authority 

under the CAA. Congress crafted the 

CAA to provide for states to take the 

lead in developing implementation 

plans, but balanced that decision by 

requiring EPA to review the plans to 

determine whether a SIP meets the 

requirements of the CAA. When 

reviewing SIPs, EPA must consider not 

only whether the state considered the 

appropriate factors in making decisions, 

but also whether it acted reasonably in 

doing so. In undertaking such a review, 

EPA does not usurp the state’s authority 

but ensures that such authority is 

reasonably exercised. 

Contrary to the comment that the 

Agency ‘‘shirks’’ its CAA obligations, 

EPA has performed its duties with 

diligence and integrity. EPA carefully 

evaluated the Haze Plan and the 


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61The CCM is available at: https://www.epa.gov/ 

economic-and-cost-analysis-air-pollutionregulations/cost-reports-and-guidance-air-pollution. 

62The Conservation Groups erred in reporting the 

2020 NEI SO2 emissions for Domtar at p. 28 of their 

comment letter. According to the 2020 NEI, the 

facility emitted 1,054 tons for Domtar, not 1,504 

tons. The 2020 NEI is located at: https://

www.epa.gov/air-emissions-inventories/2020- 

national-emissions-inventory-nei-data. 63See 2019 Guidance at 31. 

associated record and engaged in a 

thorough analysis of each control 

option, including each of the underlying 

cost assumptions used in the 

calculations. EPA independently 

evaluated each FFA, including costs, 

and compared each FFA’s control 

determination against EPA’s ‘‘Air 

Pollution Control Cost Manual’’ 

(CCM).61 After carefully considering the 

submitted comments and the entirety of 

the record, EPA is now shifting from its 

initial proposal of a partial approval and 

partial conditional approval to a partial 

approval and partial disapproval. At 

proposal, EPA specifically solicited 

comment on the adequacy of North 

Carolina’s analyses, including the FFAs 

and determination of controls necessary 

for reasonable progress, and whether the 

State met the requirements of 40 CFR 

51.308(f)(2)(i) through (iv). See 89 FR 

67358. The partial disapproval 

represents a logical outgrowth of EPA’s 

proposal which specifically solicited 

comments on these determinations and 

conclusions and reflects EPA’s receipt 

and consideration of public comments. 

EPA responds to the Conservation 

Groups’ specific comments on the FFAs 

for Domtar, PCS, and BRPP in responses 

7 through 9, below. 

Comment 7: The Conservation Groups 

provided several comments on the 

Domtar FFA.62 These comments are 

summarized in comments 7.a through 

7.c below. 

Comment 7.a: The Conservation 

Groups argue that EPA cannot approve 

North Carolina’s flawed FFA for Domtar 

and must require the installation of 

reasonable and cost-effective controls 

via a FIP. They contend that North 

Carolina ‘‘baldly rejected wet scrubber 

controls as not cost-effective’’ at a cost 

of $3,660/ton SO2 removed for the No. 

2 Hog Fuel Boiler (HFB2) and that EPA 

did not provide any rationale to support 

approval of the State’s determination. 

They also contend that EPA does not 

acknowledge multiple errors in North 

Carolina’s FFA of wet scrubber controls 

for HFB2, summarized as follows. 

Control Efficiency—The Conservation 

Groups state that North Carolina 

underestimated the control efficiency 

that a wet scrubber can achieve. They 

note that modern wet scrubbers can 

achieve at least 98 percent control 

efficiency, the vendor providing the wet 

scrubber quote states that its scrubbers 

can achieve up to 99 percent control, 

and the FFA does not explain these 

discrepancies with the 95 percent 

control efficiency assumed by North 

Carolina. 

Costs—The Conservation Groups 

assert that North Carolina overestimated 

the cost of a wet scrubber by including 

unjustified or undocumented costs. 

They allege that the State unreasonably 

accepted the use of an inflated 1.3 

retrofit factor, which Domtar attributed 

to ‘‘unanticipated delays for installing a 

wet scrubber.’’ However, they contend 

that there is no indication in the FFA 

that retrofitting HFB2 with a wet 

scrubber is unusual and the delays are 

already considered in the contingency 

fee. The Conservation Groups also argue 

that the State, without adequate 

explanation or documentation, included 

sales tax although pollution control 

equipment is tax exempt, increased the 

quoted freight and construction 

management charges, and included a 

new induced fan at a cost of $3,000,000. 

Cost Effectiveness—The Conservation 

Groups assert that, after correcting for 

the control analysis errors, the cost 

effectiveness values are $2,968/ton 

without a new induced fan and $3,244/ 

ton with a fan. They contend that these 

cost-effectiveness values and the 

$3,660/ton value are below the cost 

threshold established by other states, 

claiming that Colorado, Nevada, and 

New Mexico used a threshold of 

$10,000/ton of pollution reduced. While 

acknowledging the CAA does not 

require the State to use a bright line 

rule, they contend that the law requires 

states to explain why it has exercised it 

discretion in a given matter. The 

Conservation Groups argue that North 

Carolina must establish a threshold, or 

explain and justify some other objective 

measure, for determining costeffectiveness that is in line with other 

states’ chosen measures and apply that 

threshold consistently across its FFAs. 

They also note that EPA proposed to 

disapprove other second planning 

period SIPs where the states ‘‘applied 

arbitrary cost-effectiveness threshold or 

rejected controls that were reasonable 

and cost-effective.’’ 

Visibility Impact—The Conservation 

Groups argue that North Carolina and 

EPA disingenuously suggested that the 

State did not utilize visibility impact 

when rejecting wet scrubber controls for 

Domtar. They contend that North 

Carolina improperly considered 

visibility as a fifth factor in its decision 

to reject reasonable and cost-effective 

controls, which they state is contrary to 

EPA’s previous assertions and Congress’ 

express exclusion of visibility impact as 

one of the four statutory reasonable 

progress factors. Therefore, the 

Conservation Groups argue that North 

Carolina’s consideration of visibility 

impacts violates the CAA and the RHR 

and note that EPA has proposed to 

disapprove second planning period SIPs 

where states improperly relied of the 

lack of visibility benefit to reject 

reasonable controls. 

Response 7a: EPA agrees in part and 

disagrees in part with the assertion that 

North Carolina did not provide an 

adequate rationale to support the State’s 

determination that wet scrubber 

controls at HFB2 are not cost-effective. 

As described in more detail below, EPA 

disagrees with certain characterizations 

by the Conservation Groups about the 

rejected controls and cost analysis. At 

proposal, EPA specifically solicited 

comment on the adequacy of DAQ’s 

analyses, including the FFAs and 

determination of controls necessary for 

reasonable progress, and whether the 

State met the requirements of 40 CFR 

51.308(f)(2)(i) through (iv). See 89 FR 

67358. After further consideration of the 

analyses, as well as the comments 

received, EPA agrees that overall, North 

Carolina did not provide an adequate 

rationale to explain why the wet 

scrubber controls were not costeffective, and therefore, not included in 

the LTS as being necessary for 

reasonable progress. EPA’s evaluation of 

the State’s FFA, and explanation for 

why the justification is inadequate, is 

provided below. Due to the inadequate 

record substantiating the FFA 

conclusion regarding HFB2, together 

with the concerns discussed in response 

7.b regarding the lack of enforceable 

measures in the record for HFB1, EPA 

is disapproving the portions of the Haze 

Plan addressing 40 CFR 51.308(f)(2) and 

(3) and (i)(2) through (4). 

EPA’s first basis for disapproval of 

North Carolina’s LTS is the inadequate 

justification that the wet scrubber 

controls are not cost-effective for HFB2. 

There is no requirement in the CAA or 

the RHR for states to establish bright 

line cost effectiveness thresholds when 

evaluating control costs in FFAs. The 

CAA and the RHR require states to 

evaluate the costs of compliance, and 

EPA’s 2019 Guidance recommends that 

states follow the recommendations in 

EPA’s CCM to facilitate apples-to-apples 

comparisons of different controls 

options for the same source, and 

comparisons across different sources.63

As described in section 7.8 and 

appendix I of the Haze Plan, the State 

did not set a specific cost per ton 


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Federal Register / Vol. 89, No. 226 / Friday, November 22, 2024 / Rules and Regulations 92589 

64EPA’s RACT/BACT/LAER Clearinghouse is 

available at: https://www.epa.gov/catc/ractbactlaerclearinghouse-rblc-basic-information. 

65See page 1–21, section 5, Chapter 1 of the CCM. 

66The wet scrubber quote from LDX Solutions to 

Domtar is included at pp. 48–53 (pdf numbering) 

in appendix G–2 of the Haze Plan. 

67See table 1.1 on page 1–3, section 5, Chapter 

1 of the CCM. 

68See CCM section 5, Chapter 1, page 1–16: 

https://www.epa.gov/sites/default/files/2021-05/ 

documents/wet_and_dry_scrubbers_section_5_

chapter_1_control_cost_manual_7th_edition.pdf 

(‘‘An RF of 1 should be used to estimate costs for 

a project of average difficulty. For retrofits that are 

more complicated than average, a retrofit factor of 

greater than 1 can be used to estimate capital costs 

provided the reasons for using a higher retrofit 

factor are appropriate and fully documented. 

Similarly, new construction and retrofits of existing 

plants that are less complicated should use an RF 

less than 1. Each project should be evaluated to 

determine the appropriate value for RF.’’) 

threshold for the cost of compliance 

factor, but rather analyzed each facility 

using the information in EPA’s CCM 

and 2019 Guidance to determine 

whether a given control measure is costeffective. North Carolina determined the 

cost-effectiveness value for a wet 

scrubber on HFB2 to be $3,660/ton SO2, 

which is somewhat higher than the 

values calculated by the Conservation 

Groups ($3,244/ton with a new 

induction fan and $2,968/ton without a 

new induction fan). As explained 

below, regardless of the range of costs 

presented by both the State and the 

Conservation Groups, EPA finds that 

North Carolina did not adequately 

justify why a wet scrubber emissions 

control in that cost range was not 

necessary for reasonable progress. 

North Carolina states in appendix I 

that HFB2 is a unique set-up. It 

combusts fuels such as, lignin, natural 

gas, biomass fuel (including paper cores 

and bleached and unbleached pulp 

stock), No. 2 fuel oil, used oil, sludge, 

gases collected in the High-Volume 

Low-Concentration (HVLC) system, 

Low-Volume High-Concentration gases, 

and stripper off gases, and it is used as 

a control device for several process gas 

streams at the facility. The State 

reviewed the RACT/BACT/LAER 

Clearinghouse 64 and did not identify 

devices similar to HFB2 to which the 

cost effectiveness of a wet scrubber 

could be compared. Therefore, as 

explained in section 7.8.3.1 of the Haze 

Plan, it requested that EPA adopt the 

existing measures into the SIP as 

required by CAA section 169A(b)(2) and 

40 CFR 51.208(f)(2). Given the lack of 

other hog fuel boilers with similar 

controls, and the cost of compliance and 

the other statutory factors, North 

Carolina determined the control to not 

be necessary for reasonable progress. 

For several reasons, including 

consideration of the comments received 

after proposal, EPA ultimately does not 

find North Carolina’s justification for 

rejecting the controls compelling. First, 

although it may be accurate that most if 

not all hog fuel boilers in the country do 

not have wet scrubbers installed, 

Domtar and the State submitted a 

complete cost analysis and a vendor 

quote to install a wet scrubber on HFB2. 

It appears that it is possible to install a 

wet scrubber on the particular unit (and 

achieve at least a 95 percent SO2

reduction), and neither Domtar nor the 

State argued otherwise. Unless a wet 

scrubber cannot be installed on HFB2, 

the lack of a similar scrubber in the 

RACT/BACT/LAER Clearinghouse is not 

a relevant reason for rejecting the 

control. Second, although EPA has not 

established a bright line costeffectiveness threshold and all regional 

haze FFAs and SIP decisions will be 

evaluated on a SIP-by-SIP basis, EPA 

notes that it has found or proposed to 

find, based on its state-specific 

evaluation of other SIPs, that at least 

one other state did not adequately 

justify its determination to not adopt 

controls as part of its FFA at costeffectiveness values higher than the 

value North Carolina considered for 

Domtar. See, e.g., Air Plan Partial 

Approval and Partial Disapproval; Utah; 

Regional Haze State Implementation 

Plan for the Second Implementation 

Period; Air Plan Disapproval; Utah; 

Interstate Transport of Air Pollution for 

the 2015 8-Hour Ozone National 

Ambient Air Quality Standards; 

proposed rule, 89 FR 67208 (August 19, 

2024). It is up to each state to 

adequately justify particular cost 

decisions on a SIP-by-SIP basis, and in 

this case, EPA believes that North 

Carolina did not provide adequate 

information in the record for rejecting 

this particular emissions control. Due to 

this inadequate record, it was not 

reasonable for the State to conclude that 

a wet scrubber at HFB2 is not necessary 

for reasonable progress. 

EPA acknowledges the Conservation 

Groups’ assertions that the cost 

effectiveness values for HFB2 are below 

the thresholds used by other states 

during the second planning period, such 

as Colorado, Nevada, and New Mexico 

which elected to set cost effectiveness 

thresholds of $10,000/ton of pollutant 

removed. However, North Carolina was 

not required by the CAA or RHR to 

adopt a similar bright-line cost 

effectiveness threshold when evaluating 

control costs in FFAs, and the relatively 

high thresholds of up to $10,000/ton set 

by Colorado, Nevada, and New Mexico, 

do not automatically compel other states 

to follow suit. Each state has discretion 

to set (or not set) a reasonable cost 

threshold and provide a justification for 

FFA outcomes. 

While EPA agrees with the 

Conservation Groups’ overall 

conclusion that North Carolina did not 

adequately justify the cost control 

decisions, EPA does not necessarily 

agree with all of their specific 

contentions. For example, EPA 

disagrees with the argument that North 

Carolina underestimated the scrubber 

control efficiency at HFB2. The control 

efficiency of a wet scrubber is 

dependent upon a number of variables, 

including the type and design of the wet 

scrubber system used, the absorbing 

and/or reacting solution or slurry used, 

packed bed height, sump fluid and 

makeup water balance, scrubber pH, 

and the concentration of SO2 in the inlet 

waste gas flow.65 Domtar justified the 

use of 95 percent control efficiency by 

citing to a wet scrubber estimate from a 

vendor stating that the scrubber system 

has been designed to achieve a 95 

percent collection of SO2 emissions.66

The vendor’s estimate for Domtar is 

tailored based on the facility’s 

specifications using Domtar’s emission 

test reports and assumptions from 

similar applications. EPA agrees with 

the State that the 95 percent control 

efficiency used in the FFA is reasonable 

given the vendor’s estimate based on 

facility-specific information, the typical 

SO2 removal efficiency range for wet 

scrubbers (90 to 98 percent),67 and the 

fuel types burned in HFB2. 

The Conservation Groups included 

numerous comments on specific 

elements of the cost calculations for the 

wet scrubber at HFB2. Since EPA is 

partially disapproving the LTS with 

respect to the emissions control 

decisions at Domtar, it is not necessary 

to weigh-in on all of the specific 

deficiencies. However, there are some 

specific issues where information 

provided here may help when reevaluating the need for controls in a 

potential SIP revision. 

EPA’s CCM cannot properly account 

for all uncertainties, and thus, provides 

that a ‘‘retrofit factor’’ can be applied. 

The CCM states that it is typical for the 

retrofit factor of a wet scrubber to be 

between 0.7 and 1.3, depending on the 

level of difficulty. In any SIP revision, 

a retrofit factor greater than 1.0 should 

be adequately documented with a 

detailed justification to explain why it 

is appropriate to inflate the costs above 

those with an average retrofit 

difficulty.68 Based on the information 

provided, EPA is not able to adequately 

discern whether a 1.3 retrofit factor in 


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92590 Federal Register / Vol. 89, No. 226 / Friday, November 22, 2024 / Rules and Regulations 

69 Information regarding North Carolina’s Sales 

and Use Tax Exemption is available at: https://

edpnc.com/incentives/pollution-abatement-andrecycling/#:∼:text=Pollution%20abatement

%20equipment%20for%20

manufacturing,from%20sales

%20and%20use%20tax. 

70The CCM allows for vendor quotes to be 

incorporated into the cost analysis. See page 1–1, 

section 5, Chapter 1 of EPA‘s CCM. 

the cost analysis for the wet scrubber for 

HFB2 is inflated. 

EPA disagrees with the Conservation 

Groups’ statement that the costs of the 

‘‘unanticipated delays’’ are included in 

the contingency costs. Domtar only 

included the costs of ‘‘unanticipated 

delays’’ in the retrofit costs. These 

retrofit costs address the unexpected 

magnitude of anticipated cost elements; 

the cost of unexpected delays; the cost 

of re-engineering and re-fabrication; the 

cost of correcting design errors; the cost 

that reflect additional difficulty 

associated with installing auxiliary 

equipment; additional insulation and 

painting of piping and ductwork; costs 

associated with engineering or 

supervision during installation; and 

unanticipated delays that cause 

production cost. The contingency costs 

include other unforeseen costs such as 

the cost difference from a change in 

bank interest rate from the historically 

low 3.25 percent that was used at the 

time the Haze Plan was submitted as 

well as accounting for the cost 

difference for assuming a higher end of 

the range equipment life. The 

contingency costs also take into account 

that any capital investment dollars in 

controls that are deemed reasonable 

under regional haze would be taking 

investment dollars away from mill 

projects that would have a return on 

investments. The retrofit costs are 

completely separate from the 

contingency costs, and therefore, EPA 

disagrees that any unanticipated delay 

costs in Domtar’s FFA are being double 

counted. 

EPA agrees with the Conservation 

Groups that a sales tax charge should 

not have been included in the cost 

analysis for the wet scrubber due to 

North Carolina’s Sales and Use Tax 

Exemption for pollution abatement 

equipment (for air or stream) for 

manufacturing.69 However, removing 

the sales tax from the cost analysis for 

the wet scrubber accounts for 

approximately one percent of the total 

direct cost, which would not 

appreciably change the overall cost/ton 

identified by the FFA. 

EPA disagrees with the contention 

that North Carolina increased the 

quoted amounts for the freight charge 

and construction management without 

explanation. As explained in appendix 

I of the Haze Plan, North Carolina’s 

approval of Domtar’s decision to use the 

CCM’s methodology, instead of the 

vendor quote for the calculation of the 

freight cost, is reasonable because the 

quote was not detailed and was an 

estimate that did not consider the exact 

physical specifications and parameters 

of the plant. Furthermore, EPA disagrees 

that the construction cost was doublecounted in the overall calculated $/ton 

based on EPA’s review of Domtar’s FFA 

calculations because they are using the 

$344,196 cost, as calculated using the 

methodologies from the CCM, instead of 

the $125,000 vendor quote. 

EPA also disagrees that a $3,000,000 

new induced fan was included in the 

FFA without any documentation or 

explanation. In section 7.8.1.2 of the 

Haze Plan, North Carolina notes that an 

additional fan power would be required 

to overcome the additional pressure 

drop through the wet scrubber. 

Specifically, in appendix I, North 

Carolina notes that Domtar monitored 

the existing fan at the facility during 

startup and commissioning of the new 

electrostatic precipitator (ESP) and 

found it to be sufficient to accommodate 

the ESP but without excess capacity. 

Therefore, a new induction fan is 

needed to operate a wet scrubber as well 

as the ESP and Domtar notes that the 

$3,000,000 was a quote that it had 

received for a new induction fan. EPA 

notes that North Carolina has included 

appropriate justification for the need for 

a new induction fan in appendix G–2 

and appendix I of the Haze Plan and 

also finds that the $3,000,000 cost 

estimate was developed using 

reasonable cost assumptions and with 

adequate justification.70

EPA also disagrees with the 

Conservation Groups’ assertion that 

North Carolina relied on visibility 

considerations to reject the wet scrubber 

at HFB2. This is clear from statements 

in the Haze Plan and the NPRM. The 

Haze Plan states that North Carolina 

‘‘evaluated the SO2 emission reductions 

and associated improvements in 

visibility at the Swanquarter Wilderness 

Area associated with the wet scrubber 

control option for the No. 2 Hog Fuel 

Boiler. This information is included 

solely as supplementary information 

and is not relied upon by the State for 

its conclusions as noted in Section 

7.8.2.2.’’ Appendix I of the Haze Plan 

explains in section 3.1.2 that EPA 

requested clarification in section 7.8.1.2 

that the visibility benefits modeling for 

the wet scrubber option related to the 

Domtar HFB2 FFA is supplementary 

information and is not being relied upon 

by the State for its conclusions as noted 

in section 7.8.2.2. North Carolina 

responded that the ‘‘last paragraph of 

7.8.1.2 of the SIP was revised to explain 

that the information is included solely 

as supplementary information and that 

North Carolina did not rely upon the 

information to support its conclusions 

documented in section 7.8.2.2 of the 

SIP. This clarification was also added to 

section 7.8.1.1 of the SIP for BRPP and 

section 7.8.1.3 of the SIP for PCS 

Phosphate.’’ Furthermore, the NPRM 

states that North Carolina did not rely 

on the supplemental visibility 

information for the Domtar FFA analysis 

and conclusions and limits its 

evaluation to the four factors. See 89 FR 

67355 n.69, 67359–61. 

Comment 7.b: According to the 

Conservation Groups, EPA must require 

North Carolina’s SIP to include 

enforceable fuel restrictions for the No. 

1 Hog Fuel Boiler (HFB1). They state 

that EPA proposed to approve North 

Carolina’s exclusion of HFB1 from a 

FFA because it is equipped to only burn 

natural gas and biomass with No. 2 fuel 

oil, which is projected to emit 12 tpy of 

SO2 in 2028 (representing one percent of 

Domtar’s total SO2 emissions). However, 

they contend that EPA and North 

Carolina ignore that Domtar’s permit 

authorizes HFB1 to burn HVLC gases 

and No. 2 fuel oil. While acknowledging 

the facility’s assertion that it intends to 

keep the HVLC supply line 

disconnected indefinitely, the 

Conservation Groups state that there are 

no provisions in the SIP preventing the 

facility from reconnecting the supply 

line and burning high sulfur content 

fuel or requiring the facility to operate 

the unit ‘‘infrequently.’’ Citing EPA’s 

2019 Guidance, they state that if a SIP 

lacks the necessary provisions to make 

reasonable progress, the state is required 

to adopt emissions limits as part of its 

LTS for incorporation into the 

regulatory portion of the SIP. Therefore, 

they assert that EPA, in a FIP, must 

make the fuel use restrictions 

enforceable or perform an FFA based on 

any fuels that HFB1 could burn in the 

future. 

Response 7.b: Concerns regarding the 

lack of enforceable fuel restrictions for 

Domtar’s HFB1 form the second basis 

for disapproval of North Carolina’s LTS. 

North Carolina exempted HFB1 from 

FFA review based on the revised 2028 

SO2 emissions projection of 12 tpy SO2

(comprising 1.2 percent of Domtar’s 

total 2028 projected SO2 emissions) and 

evaluated HFB2 via a FFA based on 

2028 projected emissions of 1,010 tpy 

SO2 (comprising 98.8 percent of 

Domtar’s total 2028 projected SO2


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Federal Register / Vol. 89, No. 226 / Friday, November 22, 2024 / Rules and Regulations 92591 

71See ‘‘Projected 2028 Emissions, Revised (tons)’’ 

in table 7–55 of the Haze Plan for the 2028 

projected SO2 emissions used in the percent 

calculations. As discussed in responses 2 and 4.f, 

the State’s use of 2028 projected emissions appears 

reasonable. 

72See EPA’s Emissions Inventory System (EIS) 

Gateway available at: https://www.epa.gov/airemissions-inventories/emissions-inventory-systemeis-gateway. The 2023 annual emissions data for 

HFB1 will not be available until 2025. 

73See Haze Plan at p. 276. See table 7–56 of the 

Haze Plan at p. 277 for HFB1 SO2 emissions from 

2015 through 2020 and appendix G–2 at p.12/280 

pdf for HFB1 SO2 emissions from 2016–2018 and 

p.71/280 pdf for HFB1 SO2 emissions from 2018– 

2020. 

74 In section 10.4.1 ‘‘Exclusion of NOX from FourFactor Analysis’’ of the Haze Plan, North Carolina 

responded to FLM comments on this subject. 75See 89 FR 67358. 

emissions).71 HFB1 did not operate in 

2020, 2021, and 2022, and as the 

Conservation Groups note, the HVLC 

supply line is disconnected 

indefinitely.72 EPA acknowledges that 

performing a control analysis on an 

emissions unit with very low annual 

emissions, such as 12 tpy, would not 

likely yield any cost-effective controls 

because the low amount of SO2 removed 

would result in a higher cost per ton 

calculated for each control evaluated. 

However, the information submitted in 

the Haze Plan documents higher SO2

emissions from HFB1 in 2015, 2016, 

2017, 2018, and 2019, and notes that 

there are no state or federally 

enforceable fuel restrictions on HFB1.73

Based on the comments received and 

the information in the submitted SIP, 

EPA is concerned that the SIP 

submission does not include 

enforceable fuel restrictions for HFB1 at 

Domtar. See Comm. for a Better Arvin v. 

EPA, 786 F.3d 1169, 1175–77 (9th Cir. 

2015). This concern regarding the lack 

of enforceable measures in the record 

for HFB1, together with the inadequate 

record substantiating the FFA 

conclusion regarding HFB2, collectively 

form the basis for EPA’s disapproval of 

the portions of the Haze Plan addressing 

40 CFR 51.308(f)(2) and (3) and (i)(2) 

through (4). 

Comment 7.c: The Conservation 

Groups assert that EPA’s proposal to 

endorse North Carolina’s decision to not 

conduct analyses of NOX controls for 

Domtar was arbitrary and capricious, 

identify three boilers (No. 5 Recovery 

Boiler, HFB1, and HFB2) as significant 

sources of NOX emissions, and state that 

North Carolina failed to respond to its 

state-level comments related to NOX

control at the facility. Therefore, they 

contend that EPA must assess NOX

controls at the No. 5 Recovery Boiler, 

HFB1, and HFB2 and require the facility 

to install reasonable and cost-effective 

controls. 

Response 7.c: For the reasons 

provided in response 3, EPA disagrees 

that the Agency’s proposal to not 

require NOX FFA control evaluations of 

Domtar is arbitrary and capricious. As 

discussed therein and in the NPRM, 

North Carolina’s decision to focus on 

SO2 controls in this planning period 

appears reasonable given, among other 

things, IMPROVE monitoring data from 

the 2015–2019 five-year period showing 

that ammonium sulfate is the dominant 

visibility impairing pollutant 

contributing to regional haze at the 

Class I areas in the State. 

EPA also disagrees that North 

Carolina failed to respond to the 

comments regarding a NOX control 

evaluation of Domtar. The State 

provided responses to public comments 

regarding the August 30, 2021, proposed 

Haze Plan in appendix I of the final 

plan. North Carolina’s responses to 

public comments on nitrate and NOX

are included in section 3.4.3 

(‘‘Exclusion of NOX/Nitrate/PM’’) of 

appendix I, pages 37–38, where the 

State explains why it did not evaluate 

NOX controls during this planning 

period.74

Comment 8: The Conservation Groups 

note that North Carolina relied on PCS’ 

current title V permit limits for 

reasonable progress, which limits SO2

emissions from Sulfur Acid Plants 

(SAPs) 5, 6, and 7 to 2.5, 2.5, and 1.75 

pounds (lbs) per ton of sulfuric acid 

produced, respectively, on a 365-day 

rolling average. They also note that 

facility upgrades have lowered actual 

SO2 emissions from SAPs 5, 6 and 7 to 

1.1, 1.2, and 1.2 lbs per ton of sulfuric 

acid produced. 

The Conservation Groups contend 

that the State did not analyze lowering 

the SO2 emission limits or imposing 

work practice standards that are 

reflective of the actual emissions due to 

the plant upgrades; quote the statement 

in EPA’s 2021 Clarification Memo that 

‘‘[a] limit that is significantly higher 

than the emission rate a source is 

actually achieving does not keep the 

source from increasing its rate in the 

future;’’ and contend that if a control 

can achieve lower emissions rate, the 

State must assess it as part of an FFA. 

They disagree with North Carolina’s 

interpretation that the quoted statement 

is only applicable to situations where 

current measures are not necessary to 

make reasonable progress, noting that 

the quote is located in a section of the 

2021 Clarification Memo titled 

‘‘Determining When Existing Measures 

are Necessary for Reasonable Progress.’’ 

The Conservation Groups also state that 

North Carolina relied on the upgrades 

and actual emissions rates in 

determining that no additional controls 

are available for the purpose of 

addressing the existing visibility 

impairment attributable to 

anthropogenic sources at Swanquarter. 

They argue that the plant upgrades 

resulting in the actual lower emissions 

rates are existing measures and that the 

actual emission rates must form the 

basis for the lower emission limits for 

the plant, disagreeing with North 

Carolina’s statement that there is no 

need to impose lower arbitrary limits 

and no basis on which a lower limit 

could be set that guarantees compliance. 

The Conservation Groups contend that 

EPA must disapprove North Carolina’s 

control determinations for PCS because 

the State did not consider reasonable 

and highly cost-effective controls for the 

facility, and that the Agency must 

prepare a FIP that analyzes and requires 

lower emission limits that are reflective 

of actual emissions. 

Response 8: EPA acknowledges the 

comments related to the PCS FFA. 

However, because EPA is partially 

disapproving the portions of the Haze 

Plan addressing 40 CFR 51.308(f)(2), it 

is not necessary to address the 

Conservation Groups’ concerns 

regarding the PCS FFA at this time. At 

proposal, EPA solicited comments on, 

among other things, ‘‘the adequacy of 

the permit conditions, including 

associated monitoring, recordkeeping, 

and reporting, and whether the State has 

met the requirements of 40 CFR 

51.308(f)(2)(i) through (iv).’’ 75 The 

decision to disapprove the portions of 

the Haze Plan addressing 40 CFR 

51.308(f)(2) is a logical outgrowth of the 

proposal; EPA has given further 

consideration to the question of the 

adequacy of these provisions, the 

comments received, and the totality of 

the analyses that constitute the LTS and 

RPGs. As discussed above, EPA will be 

obligated under CAA section 110(c)(1) 

to promulgate a FIP within two years 

after the effective date of this partial 

disapproval, unless the state submits, 

and the EPA approves, a SIP revision 

that satisfies the requirements of 40 CFR 

51.308(f)(2) and (3) and (i)(2) through (4) 

before EPA promulgates the FIP. The 

public will have the opportunity to 

comment on, among other things, 

whether the proposed FIP or the 

proposed SIP action satisfies the FFA 

requirements of 40 CFR 51.308(f)(2). 

Comment 9: The Conservation Groups 

contend that the State’s and EPA’s 

analyses of BRPP are no longer relevant 

since, according to EPA’s Enforcement 

and Compliance History Online 

database, the facility is permanently 


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92592 Federal Register / Vol. 89, No. 226 / Friday, November 22, 2024 / Rules and Regulations 

76The September 18, 2024, letter requesting 

permit termination is in the docket for this 

rulemaking. 

77The September 24, 2024, permit recission letter 

is in the docket for this rulemaking. 

78See 40 CFR 51.308; 64 FR 35714 (July 1, 1999); 

and 82 FR 3078 (January 10, 2017). 

79See 2019 Guidance at pp. 46–48. 

80See 2021 Clarifications Memo at p. 6. 

closed as of June 2023. Therefore, they 

assert that EPA’s final SIP action must 

include coordinating and acting in 

accordance with the Comprehensive 

Environmental, Response, 

Compensation, and Liability Act 

(CERCLA) Superfund efforts for the site, 

along with ensuring all existing air 

permits for the facility are revoked. 

Response 9: EPA agrees that North 

Carolina’s FFA analysis and the 

Agency’s evaluation of BRPP in the 

NPRM are no longer relevant. On 

September 18, 2024, BRPP requested the 

termination of its title V permit for the 

BRPP Canton Mill, Air Quality Permit 

No. 08961T32, with Facility ID 4400159, 

effective immediately.76 This letter 

states that none of the sources in the 

BRPP title V permit have been operating 

since June 2023. On September 23, 

2024, DAQ sent a letter rescinding the 

permit effective on the date of the 

letter.77 Regarding CERCLA, the CAA 

does not require regional haze SIPs to 

provide for coordination and 

consistency with Superfund efforts. 

Comment 10: The Conservation 

Groups assert that EPA cannot approve 

North Carolina’s SIP revision because it 

does not include practically enforceable 

emissions limitations and because this 

deficiency is not cured in the 

Commitment Letter supporting the 

conditional approval. They also assert 

that EPA must disapprove the SIP 

revision because the Commitment Letter 

does not identify specific enforceable 

measures as required under CAA 

section 110(k)(4) and only contains 

mere promises to adopt unspecified and 

sometimes unenforceable monitoring, 

recordkeeping, and reporting measures 

to correct the deficiencies in the SIP 

revision and because EPA ignores 

additional practical enforceability issues 

in the permit provisions identified for 

incorporation into the SIP. 

Response 10: It is unnecessary to 

respond to the Conservation Groups’ 

comments regarding the sufficiency of 

the Commitment Letter or the 

practicable enforceability of the permit 

terms identified for incorporation into 

the SIP because EPA is shifting from its 

initial proposal of a partial approval and 

partial conditional approval to a partial 

approval and partial disapproval. This 

action does not incorporate any permit 

conditions into the SIP because the 

partial disapproval includes the LTS, 

and the Commitment Letter is now 

moot. EPA’s decision to disapprove the 

portions of the Haze Plan addressing 40 

CFR 51.308(f)(2) is a logical outgrowth 

of the initial proposal and EPA’s 

consideration of the comments received. 

As discussed above, EPA will be 

obligated under CAA section 110(c)(1) 

to promulgate a FIP within two years 

after the effective date of this partial 

disapproval, unless the State submits, 

and EPA approves, a SIP revision that 

satisfies the requirements of 40 CFR 

51.308(f)(2) and (3) and (i)(2) through (4) 

before EPA promulgates the FIP. Any 

emission limitations identified for 

incorporation into the SIP in such a SIP 

revision (or into a FIP in the case of an 

eventual FIP) must be legally and 

practicably enforceable, and EPA 

encourages the State to consider the 

Conservation Groups’ comments if the 

State opts to develop a SIP revision. 

Comment 11: The Conservation 

Groups contend that EPA’s proposal to 

conditionally approve North Carolina’s 

RPGs violates the CAA and RHR. They 

assert that North Carolina impermissibly 

reversed the ‘‘long-standing’’ SIP 

planning sequence by setting its RPGs 

before conducting FFAs or finalizing its 

LTS. They argue that since the RPGs are 

based on VISTAS’ modeling conducted 

in 2020, before the State identified the 

controls necessary for reasonable 

progress based on the four statutory 

factors and proposed its LTS, the RPGs 

do not meet the RHR requirement that 

they must be based on enforceable SIP 

measures. They also assert that the State 

and EPA ignored the 2019 Guidance 

explaining that a state must adjust its 

RPGs if it conducted modeling for RPGs 

before making final LTS determinations. 

The Conservation Groups maintain that 

EPA ignores that the State’s RPGs do not 

reflect the visibility improvements that 

the LTS controls will achieve, must 

disapprove the RPGs, and must require 

the State to adjust them to reflect 

enforceable limitations in the SIP. 

Response 11: EPA agrees with 

disapproving North Carolina’s RPGs but 

differs on the reason for disapproval. 

EPA reiterates that the process for 

establishing RPGs for each Class I area 

is prescribed in the RHR amendments 

and discussed in related guidance.78 79 80

The RHR requires states with Class I 

areas to establish RPGs that reflect the 

visibility conditions projected to be 

achieved by the end of the second 

planning period as a result of the 

‘‘enforceable emission limitations, 

compliance schedules, and other 

measures required under the long-term 

strategy.’’ See 40 CFR 51.308(f)(3). As 

previously explained, EPA is 

disapproving the portions of the Haze 

Plan addressing 40 CFR 51.308(f)(2). 

Therefore, because the requirements in 

40 CFR51.308(f)(3) are dependent upon 

40 CFR 51.308(f)(2), EPA is 

disapproving the RPGs because they 

reflect a deficient LTS. 

The sequencing of the development of 

the RPGs is inconsequential here 

because EPA has determined that the 

State’s LTS is deficient. Therefore, 

because the Haze Plan does not include 

an approvable LTS, and compliance 

with 40 CFR 51.308(f)(3) is dependent 

on compliance with 40 CFR 51.308(f)(2), 

EPA is disapproving the RPGs, and the 

State should re-evaluate them as part of 

its potential SIP revision. 

Comment 12: The Conservation 

Groups assert that EPA’s proposal to 

approve North Carolina’s interstate 

consultations is arbitrary and 

capricious, and violates the CAA and 

RHR. They contend that EPA did not 

conduct an independent analysis of the 

State’s consultation process to 

determine whether it satisfies the 

regulatory requirements. Additionally, 

they argue that State’s consultations 

were ‘‘incomplete, inadequately 

documented, and failed to provide for 

coordinated emissions management 

strategies with other states.’’ 

The Conservation Groups maintain 

that the VISTAS modeling was flawed 

and the source selection process was 

unreasonable, both of which were relied 

on by North Carolina to identify sources 

from other states that contribute to 

visibility impairment in its five Class I 

areas. They cite NPCA’s analysis using 

the 2020 NEI and the 2023 Clean Air 

Markets Program Data (CAMPD) to show 

that there are 169 sources with Q/d 

greater than or equal to five, spanning 

19 different states, that likely contribute 

to visibility impairment at North 

Carolina’s Class I areas. They note that 

North Carolina did not request 

consultation with some of the states or 

regarding some sources that were 

identified by the NPCA, including 

consulting with Kentucky on Ghent 

Station that they contend is likely 

contributing to visibility impairment at 

Great Smoky Mountains with a Q/d of 

40.36, and Louisiana, which has nine 

sources that they contend likely 

contribute to visibility impairment in 

North Carolina’s Class I areas. 

Regarding the adequacy of 

documentation of consultations, the 

Conservation Groups point to North 

Carolina’s statement in its SIP revision 

that appendix F–1 contains the 

consultation letters from North Carolina 

to each VISTAS state, along with the 


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81The 16 sources are: Entergy Arkansas Inc– 

Independence Plant in Arkansas; Plant Bowen in 

Georgia; Gibson and Indiana Michigan Power DBA 

AEP Rockport in Indiana; Tennessee Valley 

Authority (TVA)–Shawnee in Kentucky; New 

Madrid Power Plant-Marston in Missouri; Cardinal 

Power Plant–Cardinal Operating Company 

(Cardinal Power Plant); Duke Energy Ohio—Wm. H. 

Zimmer Station (Duke–Zimmer); and General James 

M. Gavin Power Plant (Gavin Power Plant) in Ohio; 

Homer City Gen LP/Center and Genon NE Mgmt 

Co/Keystone Station in Pennsylvania; Eastman and 

TVA–Cumberland in Tennessee; Jewell Coke 

Company LLP in Virginia; and Allegheny–Harrison 

and Monongahela–Pleasants Power Station in West 

Virginia. North Carolina requested FFAs of nonVISTAS sources through VISTAS. 

82Appendix F–3d of the Haze Plan includes the 

June 22, 2020, letter from North Carolina, through 

VISTAS, requesting a FFA of the Gavin Plan and 

a October 29, 2020, letter of response from Ohio. 

The 2020 Ohio letter states that the Gavin Plant 

operates two coal-fired boilers (B003 and B004) 

which have FGDs that operate year-round with a 95 

percent control efficiency. Ohio requested an SO2

FFA from the Gavin Plant, and Ohio stated in its 

letter that the plant was considered effectively 

controlled for NOX with a SCR system with 90 

percent control efficiency. 

responses. However, the Conservation 

Groups found that appendix F–1 only 

contains North Carolina’s letters. 

Instead of providing the responses it 

received (only from Tennessee and West 

Virginia), the State provides only 

summaries of the responses. 

Furthermore, while North Carolina 

requested consultations with Kentucky, 

Georgia, and Virginia, the responses 

were not documented, including 

whether those states shared their FFAs 

for the identified sources, whether there 

were agreements or disagreements 

between the parties, or whether 

disagreements were reconciled. 

Next, the Conservation Groups assert 

that North Carolina ‘‘effectively 

conducted an ‘agree to do nothing’ 

consultation process,’’ which violates 

the CAA and RHR requirement to 

engage in substantive consultation to 

develop coordinated strategies that 

reduce emissions with other states in 

order to make reasonable progress 

during the second planning period. 

They note that only one (Eastman 

Chemical Company in Tennessee) out of 

the 16 sources that the State requested 

consultation was required to install new 

emission controls. The Conservation 

Groups argue that North Carolina 

acquiesced to other states’ 

determinations for their respective 

sources. For example, they state that 

based on the VISTAS modeling and 

source selection process North Carolina 

relied on, the General James M. Gavin 

Power Plant (Gavin Plant) in Ohio is the 

biggest contributor to visibility 

impairment in Great Smoky Mountains, 

Joyce Kilmer, and Shining Rock, the 

second biggest contributor at Linville 

Gorge, and the fourth biggest contributor 

at Swanquarter. Nonetheless, they state 

that North Carolina decided it was 

satisfied with Ohio’s determination that 

the Gavin Plant would not be required 

to install new emission controls. 

Response 12: In response to the 

Conservation Groups’ comments that 

the VISTAS modeling was flawed, 

North Carolina’s source selection 

process was unreasonable, and the State 

should have requested consultation 

based on NPCA’s Q/d analysis, see 

responses 1 and 2. 

EPA disagrees with the contention 

that EPA’s review of North Carolina’s 

interstate consultation process was a 

box checking exercise. EPA 

independently reviewed all of the 

consultation documentation provided 

by North Carolina within its Haze Plan. 

EPA also disagrees with the comment 

that North Carolina conducted a ‘‘donothing’’ approach to consultation, 

which violates CAA and RHR 

requirements to engage in substantive 

consultation to develop ‘‘coordinated 

emission reduction strategies’’ with 

other states. 40 CFR 51.308(f)(2) requires 

a state to consult with those states that 

have emissions that are reasonably 

anticipated to contribute to visibility 

impairment in the mandatory Class I 

area. The State appears to have 

reasonably complied with 40 CFR 

51.308(f)(2)(ii) by consulting with 10 

other states and requesting FFAs for 16 

facilities located within those states 

with visibility impacts to North 

Carolina’s Class I areas exceeding the 

State’s sulfate PSAT threshold at one or 

more of North Carolina’s Class I areas.81

Further, EPA disagrees with the 

Conservation Groups’ assertion that 

North Carolina acquiesced to other 

states’ determinations for their 

respective sources. For example, North 

Carolina assessed and agreed with 

Ohio’s response on the Gavin Plant, and 

therefore, no further action is required 

under the RHR’s consultation 

provisions.82 40 CFR 51.308(f)(2)(ii) 

does not require further action when a 

state agrees with another state’s 

determination that no emission 

reductions are necessary to make 

reasonable progress. 

Moreover, EPA disagrees with the 

Conservation Groups’ contention that 

North Carolina did not adequately 

document its consultation process 

within its Haze Plan. Although the RHR 

requires a state to demonstrate that it 

has included in its implementation plan 

all measures agreed to during interstate 

consultations or a regional planning 

process, or measures that will provide 

equivalent visibility improvement, and 

to describe any actions taken in the 

event states disagree with one another 

on the emission reduction measures 

necessary to achieve reasonable progress 

in Class I areas, the RHR does not 

prescribe a specific type of 

documentation to demonstrate that the 

interstate consultation requirements of 

40 CFR 51.308(f)(2)(ii) have been met. 

North Carolina documented its 

correspondence in appendix F–1 with 

the states listed in table 10–2 and 

summarized responses from those states 

in section 10.1.1 of the Haze Plan. 

Therefore, it appears that the State 

reasonably satisfied the RHR’s 

documentation requirements. However, 

the interstate consultation requirement 

at 40 CFR 51.308(f)(2)(ii) is a part of 40 

CFR 51.308(f)(2), which is subject to the 

partial disapproval. To the extent that 

the Domtar facility contributes to 

visibility impairment at out-of-state 

Class I areas, EPA recognizes that the 

State (or EPA in the case of an eventual 

FIP), may need to reconsider the 

interstate consultation element under 40 

CFR 51.308(f)(2)(ii). To the extent that 

the Conservation Groups have concerns 

about facilities outside of North 

Carolina, including the Gavin Plant in 

Ohio and Ghent Station in Kentucky, 

any public comments related to out-ofstate sources should be provided during 

the public comment periods regarding 

those states’ haze plans. North Carolina 

lacks authority to regulate these out-ofstate sources, and therefore, EPA cannot 

require other states to implement 

control measures through action on 

North Carolina’s Haze Plan. 

Comment 13: The Conservation 

Groups maintain that EPA blindly 

proposes to approve the State’s 

consultation with the FLMs by not 

conducting an independent review or 

analysis. They note that North Carolina 

provided the FLMs an opportunity to 

consult on the draft SIP revision, but 

argue that the State failed to engage in 

meaningful consultation with the FLMs 

and largely ignored and failed to 

adequately respond to the FLMs’ 

comments. For these reasons, they argue 

EPA’s proposal to approve the State’s 

FLM consultation process is arbitrary 

and capricious and violates the CAA 

and RHR. 

The Conservation Groups argue that 

North Carolina treated the FLM 

consultation process as a ‘‘box checking 

exercise’’ by providing terse and 

inadequate responses to FLMs’ 

recommendations. The Conservation 

Groups contend that North Carolina did 

not incorporate FLM suggestions that 

North Carolina should conduct FFAs of 

NOX controls for the State’s major 

sources due to inaccurate modeling 

results; the source screening process 

used ‘‘unreasonably high thresholds;’’ 


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83The Conservation Groups say ‘‘higher 

thresholds’’ on page 46 of their comments, but EPA 

believes that this is an error because the context of 

the statement indicates that they intended to say 

‘‘lower thresholds.’’ 

84Section 3.2 of appendix I addresses NPS 

comments received during the State comment 

period on the proposed Haze Plan. Section 10.4 of 

the Haze Plan addresses FLM comments received 

prior to the State comment period on a draft plan, 

including section 10.4.2 related to source selection 

and section 10.4.3 related to evaluation of NOX

controls for the Duke Energy EGUs. 

85See section 10.4.1 of the Haze Plan at pp. 320– 

335. 

86FWS and USFS representatives were also 

invited to attend the May 14 and 25, 2021, North 

Carolina-NPS consultation meeting. See section 

10.4 of the Haze Plan. 

87See response 15. 

lower thresholds 83 would have led to 

identification of additional facilities; 

and the State should conduct FFAs of 

NOX controls for the Duke Energy EGUs. 

The Conservation Groups contend 

that since North Carolina’s source 

selection, source-specific analyses, LTS, 

and RPGs violate the CAA and RHR, the 

State’s FLM consultations were based 

on a SIP revision that did not meet the 

statutory and regulatory requirements. 

They argue that EPA must issue a FIP 

that corrects the errors in the SIP 

revision and consult with the FLMs 

anew, meaningfully considering, 

incorporating, and responding to FLM 

recommendations. 

Response 13: The FLMs play 

important roles in addressing visibility 

at Class I areas, and 40 CFR 51.308(i)(3) 

requires states to include a description 

of how they address any comments 

provided by the FLMs during the 

opportunity for consultation. However, 

neither the CAA nor the RHR require a 

state to agree with the FLM 

recommendations, nor do they specify 

the degree of consideration that must be 

given to those comments. Rather, 40 

CFR 51.308(i)(3) requires a state to 

‘‘include a description of how it 

addressed any comments provided by 

the Federal Land Managers’’ within its 

haze plan. 

North Carolina appears to have 

reasonably complied with this 

requirement by documenting how it 

addressed the FLMs’ comments 

contained in appendix H and appendix 

I in both section 10.4 of the Haze Plan 

and in section 3.2 of appendix I of its 

Haze Plan.84 For example, North 

Carolina provides an in-depth rationale 

(approximately 15 pages) for why it 

disagrees with NPS’ comment 

recommending inclusion of NOX in the 

FFAs in section 10.4.1 of the Haze 

Plan.85 Further, FLM consultation must 

take place at least 60 days prior to the 

state public comment period on any 

haze plan or plan revision pursuant to 

40 CFR 51.308(i)(2). North Carolina 

initiated consultation with the FLMs on 

April 5, 2021, which was 147 days 

before the opening of the State’s public 

comment period on August 30, 2021. In 

addition, North Carolina met with NPS 

upon request on May 14 and May 25, 

2021, to discuss NPS’ feedback in more 

detail.86

EPA recognizes that North Carolina 

appears to have reasonably followed all 

of processes required for FLM 

consultation consistent with 40 CFR 

51.308(i). However, EPA is disapproving 

North Carolina’s FLM consultation 

under 40 CFR 51.308(i)(2) through (4) 

because compliance with that 

requirement is dependent on fulfilling 

the substantive requirements of 40 CFR 

51.308(f)(2) (LTS). For reasons 

discussed elsewhere in this notice, EPA 

is disapproving the portions of the Haze 

Plan addressing 40 CFR 51.308(f)(2) and 

(3). When EPA disapproves an LTS, the 

state (in the case of a SIP revision) or 

EPA (in the case of a FIP) must 

redevelop an LTS that complies with 

the statutory and regulatory 

requirements and provide meaningful 

consultation on the substance of the 

LTS created to replace the substantively 

disapproved one. Even though it 

appears North Carolina reasonably 

consulted with the FLMs to develop the 

LTS, because the LTS is disapproved, 

the consultation component must also 

be disapproved. Therefore, the State (for 

a SIP revision) or EPA (for a FIP) must 

again consult with the FLMs on a 

revised LTS in order to develop an 

approvable LTS. 

Regarding the merits of the FLM 

comments summarized by the 

Conservation Groups and repeated by 

the NPS in its comments on this 

rulemaking, see responses 17 and 18. 

Regarding a FIP, as discussed above, 

EPA will be obligated under CAA 

section 110(c)(1) to promulgate a FIP 

within two years after the effective date 

of this partial disapproval, unless the 

State submits, and EPA approves, a SIP 

revision that satisfies the requirements 

of 40 CFR 51.308(f)(2) and (3) and (i)(2) 

through (4) before EPA promulgates the 

FIP.87

Comment 14: The Conservation 

Groups assert that EPA should not rely 

on North Carolina’s environmental 

justice (EJ) analysis due to deficiencies 

and that the Agency should conduct an 

independent analysis. The Conservation 

Groups contend that North Carolina 

failed to respond to their and other 

commenters’ EJ concerns raised during 

the State’s public hearing. They also 

maintain that North Carolina’s EJ 

analysis is inadequate because it does 

not consider the communities 

surrounding the facilities but instead 

focuses on the communities 

surrounding the Class I areas and that 

they are not aware of any other state that 

employed this approach. They state that 

out of the 400-page SIP revision (not 

including appendices), North Carolina’s 

efforts only include two pages 

discussing public participation plans, 

three pages of maps, and less than one 

page in its response to comments. The 

Conservation Groups assert that the SIP 

revision is ‘‘entirely void of any analysis 

of how it would benefit North Carolinaidentified communities of concern for 

environmental justice.’’ 

The Conservation Groups argue that 

EPA’s proposal fails to recognize the 

unreasonable approach that the State 

used to identify the geographic areas for 

consideration in the EJScreen Reports, 

an approach they describe as unique, 

and that they are not aware of any other 

state that employed this approach. They 

also assert that EPA’s final action must 

provide clarification to the states that 

impacts local to the sources should be 

considered because North Carolina’s 

analysis failed to consider the impacts 

of SO2 and NOX on communities near 

the emission sources. They argue that 

North Carolina’s SIP revision does not 

contain any analysis on how it would 

benefit the identified communities with 

EJ concerns, except in the State’s 

assertion about the visibility 

improvement in its Class I areas through 

reductions in SO2 and NOX have 

reduced impacts on the public, 

including vulnerable communities. 

The Conservation Groups state that 

the pollutants that contribute to 

visibility impairment in Class I areas 

can also cause significant public health 

impacts in the area surrounding the 

source, particularly communities of 

color and low-income communities. 

They argue that EPA’s final action 

should consider and independently 

analyze the impacts the sources have on 

communities across the State, 

particularly in communities that are 

disproportionately burdened by 

environmental pollution and explain 

how a strong regional haze plan will 

address those adverse impacts. 

Based on the Executive Orders (E.O.s) 

in place since 1994, they maintain that 

EPA is required to incorporate EJ as 

‘‘part of its mission by identifying and 

addressing . . . disproportionately high 

and adverse human health or 

environmental effects of its program, 

policies, and activities,’’ which they 

argue to be applicable to regional haze 

SIP actions’ impacts on minority 

populations and low-income 


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88The ‘‘Executive Order on Revitalizing Our 

Nation’s Commitment to Environmental Justice for 

All’’ is available at: https://www.whitehouse.gov/ 

briefing-room/presidential-actions/2023/04/21/ 

executive-order-on-revitalizing-our-nationscommitment-to-environmental-justice-for-all/. 

89See ‘‘EPA Legal Tools to Advance 

Environmental Justice’’, May 2022, available at: 

https://www.epa.gov/system/files/documents/2022- 

05/EJ%20Legal%20Tools%20

May%202022%20FINAL.pdf at pp. 35–36. 90See 89 FR 47481. 

populations. Additionally, they argue 

the directive to incorporate EJ into all of 

the Agency’s actions was reaffirmed by 

the Biden Administration through backto-back E.O.s directed to Federal 

agencies, including EPA, and again in 

2023 when the Administration issued 

the ‘‘Executive Order on Revitalizing 

Our Nation’s Commitment to 

Environmental Justice for All.’’ 88

The Conservation Groups maintain 

that EPA has the resources, including 

EJScreen, to provide a robust analysis of 

the EJ impacts of North Carolina’s SIP 

revision. Using the EJScreen toolkit, 

their analysis shows five facilities 

(DEC—Belews Creek; DEC—Cliffside, 

DEC—Marshall, Domtar, and PCS) are 

surrounded by communities that have 

EJ indicators in the high percentiles. 

Response 14: EPA disagrees with this 

comment but acknowledges the 

EJScreen information provided by the 

Conservation Groups. The regional haze 

statutory provisions do not explicitly 

address considerations of EJ and neither 

do the regional haze regulatory 

requirements of the second planning 

period in 40 CFR 51.308(f), (g), and (i). 

However, the lack of explicit direction 

does not preclude the State from 

addressing EJ in its SIP submission. As 

explained in ‘‘EPA Legal Tools to 

Advance Environmental Justice,’’ 89 the 

CAA provides states with the discretion 

to consider EJ in developing rules and 

measures related to regional haze. While 

a state may consider EJ under the 

reasonable progress factors, neither the 

statute nor the regulation requires states 

to conduct an EJ analysis for EPA to 

approve a SIP submission. The 2021 

Clarifications Memo states in section 

5.6: ‘‘EPA encourages states to consider 

whether there may be equity and 

environmental justice impacts when 

developing their regional haze strategies 

for the second planning period. . . . 

States have discretion to consider 

environmental justice in determining 

the measures that are necessary to make 

reasonable progress and formulating 

their long-term strategies, as long as 

such consideration is reasonable and 

not contrary to the regional haze 

requirements.’’ 

In this instance, North Carolina 

elected to consider EJ under the 

reasonable progress factors in section 

10.6 and appendix F–5 of the Haze Plan. 

The State ran EJScreen for four of its 

five Class I areas (excluding the Great 

Smoky Mountains due to its size), and 

based on the results of the EJScreen, it 

outlined a five-step outreach plan in 

section 10.6 to ensure the opportunity 

for meaningful community involvement 

during the state-level comment period 

for the Haze Plan. In appendix I of the 

Haze Plan, in response to an EJ 

comment received during the public 

comment period, the State notes that 

EPA’s 2021 Clarifications Memo 

encourages states to consider EJ and 

encourages states to consider whether 

there may be equity and EJ impacts 

when developing their regional haze 

strategies for the second planning 

period while noting that states have 

discretion to consider EJ in determining 

the measures that are necessary to make 

reasonable progress and formulating 

LTS, as long as such consideration is 

reasonable and not contrary to the 

regional haze requirements. North 

Carolina explains in its response that at 

the time of the issuance of the memo, 

the State had mostly completed the 

proposed plan for public comment 

which was issued on August 30, 2021. 

The response also states that North 

Carolina’s EJ analysis and additional 

outreach was an adequate response 

given the short amount of time between 

when EPA issued its July 8, 2021, 

guidance and when regional haze SIPs 

were due to EPA on July 31, 2021. 

As discussed above, the CAA and 

RHR neither prohibit nor require an 

evaluation of EJ with a regional haze 

SIP. EPA has evaluated North Carolina’s 

SIP submission against the statutory and 

regulatory regional haze requirements 

and determined that it satisfies those 

minimum requirements. For these 

reasons, the State is not required to 

address the Conservation Groups’ 

alleged EJ inadequacies in its SIP 

revision, and EPA is not required to 

conduct an independent EJ analysis. 

Comment 15: The Conservation 

Groups assert that EPA must disapprove 

North Carolina’s SIP revision and issue 

a regional haze FIP for the State for the 

reasons discussed in the comments 

summarized in comments 1 through 14, 

above. They also contend that the 

Agency should issue a regional FIP 

covering the Region 4 states because 

‘‘multiple states in Region 4 have 

developed second planning period SIPs 

that violate’’ the CAA and RHR, 

pointing to reliance on ‘‘invalid VISTAS 

modeling and source selection process,’’ 

and must disapprove Georgia’s SIP 

revision. The Conservation Groups also 

contend that EPA must act swiftly to 

issue a FIP because North Carolina’s 

Haze Plan for the second planning is 

years behind schedule. 

Response 15: EPA has responded to 

the Conservation Groups’ rationale for 

disapproval and a FIP in responses 1 

through 14. As discussed above, the 

Agency is approving in part and 

disapproving in part North Carolina’s 

Haze Plan. Therefore, EPA will be 

obligated under CAA section 110(c)(1) 

to promulgate a FIP within two years 

after the effective date of this partial 

disapproval, unless the State submits, 

and EPA approves, a SIP revision that 

satisfies the requirements of 40 CFR 

51.308(f)(2) and (3) and (i)(2) through (4) 

before EPA promulgates the FIP. The 

Conservation Groups’ comments 

regarding a regional FIP are beyond the 

scope of this rulemaking because this 

rulemaking relates solely to North 

Carolina’s Haze Plan and EPA has not 

proposed action on all of the regional 

haze SIPs submitted by other states in 

Region 4. Regarding Georgia’s regional 

haze plan, EPA proposed to approve 

that SIP revision in a separate 

rulemaking on June 3, 2024, and the 

Agency will take final action through 

that separate rulemaking.90

Comment 16: NPS states that North 

Carolina’s SIP process missed a key 

CAA section 169A(d) consultation 

requirement because the State’s public 

notice of its regional haze SIP did not 

include a summary of the FLMs’ 

conclusions and recommendations. NPS 

asserts that this statutory requirement 

ensures public transparency in the SIP 

development process by requiring states 

to alert the public that the FLMs provide 

comments and to provide a short 

summary of the recommendations in the 

notice to ease the burden of locating and 

interpreting these comments in the draft 

SIP revisions. Therefore, NPS 

recommends that EPA acknowledge and 

address this procedural error when 

taking final action on North Carolina’s 

SIP. 

Response 16: Section 169A(d) of the 

CAA requires states to include a 

summary of the conclusions and 

recommendations of the FLMs in the 

notice to the public. This section sets 

the expectation as to what states must 

share with the public regarding the 

FLMs’ comments. North Carolina’s 

August 30, 2021, proposed haze plan 

subject to public notice contained the 

FLMs’ conclusions and 

recommendations in appendix H, which 

is sufficient because it provides the 

entirety of the FLMs’ conclusions and 

recommendations, rather than a stategenerated summary. However, because 

EPA is disapproving the portions of the 


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91The five Duke Energy EGUs identified by NPS 

are DEC—Belews Creek, DEC—Cliffside, DEC— 

Marshall, DEP—Roxboro, and DEP—Mayo. 

Haze Plan addressing 40 CFR 

51.308(f)(2) and (3), North Carolina (for 

a SIP revision) or EPA (for a FIP) must 

again satisfy the requirements of CAA 

section 169A(d). 

Comment 17: NPS disagrees with 

EPA’s proposal to approve the source 

and pollutant selection portion of the 

LTS. NPS states that North Carolina 

unreasonably applied the AoI and PSAT 

results to exclude significant sources 

and pollutants from analysis, that it has 

raised these concerns with the State 

since May 2021, and that neither North 

Carolina nor EPA substantively 

addressed these concerns. 

Source Selection Approach—NPS 

argues that North Carolina’s source 

selection thresholds are ‘‘excessively 

high’’ and are ‘‘flawed and 

counterproductive’’ to remedying 

existing visibility impairment. 

According to NPS, the VISTAS source 

selection approach, relying on a 

percent-of-total-impact threshold for 

selecting each facility, results in an 

individual facility needing to have a 

greater impact on visibility to be 

selected for more impaired Class I areas 

than with less impaired ones. NPS states 

that the AoI percent-of-total-impact 

threshold for selecting a facility is 74 

times higher for Mammoth Cave 

National Park (Mammoth Cave) and 19 

times higher for Great Smoky Mountains 

when compared to Everglades National 

Park, the least impacted NPS Class I 

area in the region. NPS argues that this 

approach resulted in the selection of 

very few sources for FFAs in a region 

experiencing significant visibility 

impairment and states that no North 

Carolina source was selected for impacts 

to Great Smoky Mountains or other NPS 

Class I areas. NPS also argues that it is 

difficult to assess reasonable progress if 

few sources are brought forward for 

FFAs. NPS asserts that neither EPA nor 

North Carolina substantively addressed 

this issue or described how the source 

selection thresholds are consistent with 

the need to demonstrate reasonable 

progress. 

Pollutant Selection Approach—NPS 

asserts that North Carolina used an 

outdated 2011 modeling platform to 

draw conclusions about which 

pollutants are responsible for visibility 

impairment. NPS states that recent 

monitoring data shows that the 

ammonium nitrate contribution on the 

20 percent most-impaired days has 

increased since 2011 and is now a 

significant component of visibility 

impairment in Mammoth Cave and 

Shenandoah National Park 

(Shenandoah). While NPS agrees that 

sulfate is the dominant contributor to 

visibility impairment in those areas, it 

notes that nitrate contributions have 

more than doubled in recent years and 

are also significant. NPS encourages 

EPA to consider the 2021 Clarification 

Memo’s direction on pollutant selection 

in assessing North Carolina’s approach 

and recommends the evaluation of 

North Carolina’s sources for 

opportunities to reduce NOX emissions. 

Response 17: See response 1 regarding 

the 2011 base year and response 2 

regarding North Carolina’s source 

selection approach. See response 3 

regarding nitrate contributions at the 

North Carolina Class I areas and 

pollutant selection. Additionally, there 

is no evidence provided by NPS that 

Mammoth Cave or Shenandoah are 

affected by emissions from within North 

Carolina (in particular, NOX emissions 

which may impact nitrate). Therefore, 

contributions to nitrate at those Class I 

areas are not relevant to North 

Carolina’s Haze Plan. 

Comment 18: NPS notes that North 

Carolina did not conduct FFAs of NOX

and SO2 emissions at five Duke Energy 

EGUs identified by NPS for such an 

evaluation, instead concluding that SO2

emissions from these EGUs are 

effectively controlled without any 

substantive analysis.91 NPS asserts that 

EPA’s proposed determination that 

FFAs are not necessary for these EGUs 

and that they are effectively controlled 

for SO2 is flawed and inconsistent with 

EPA guidance because it: (1) does not 

consider the full suite of EPA guidance 

on effective controls, (2) relied on 

flawed assumptions to estimate SO2

control efficiencies, and (3) did not 

assess NOX emissions. NPS 

recommends that EPA require FFAs for 

SO2 and NOX at these EGUs which 

should consider whether scrubber 

upgrades or optimizations are cost 

effective. 

EPA Guidance—NPS maintains that 

EPA narrowly viewed the Agency’s 

guidance in relying heavily on two 

effective control examples in the 2019 

Guidance—(1) EGUs with add-on flue 

gas desulfurization (FGD) that meet the 

0.2 lb/MMBtu MATS SO2 limit for coalfired EGUs, and (2) EGUs that installed 

FGD during the first implementation 

period that operates year-round with an 

effectiveness of at least 90 percent. NPS 

states that EPA did not consider 

additional guidance that ‘‘caveats how 

‘off-ramps’ to source selection should be 

used,’’ pointing to section 2.3 of the 

2021 Clarifications Memo. NPS states 

that, with respect to MATS, the 

guidance recommends that states should 

also consider control equipment past 

performance in their reasonable 

progress determinations and 

recommends reasonable actions to 

ensure controls are maintained and 

operated to achieve optimal 

performance. NPS states that the Duke 

Energy EGUs have operated at lower 

emission rates in the past and that its 

evaluation of SO2 and NOX emissions 

information in the CAMPD 

demonstrates that SO2 and NOX

emissions generally increased in recent 

years, suggesting that the controls at 

these facilities may not be operating to 

maintain optimum performance or 

achievable emission rates. 

NPS also argues that FGD installed 

after 2007 should meet a control 

effectiveness of 95 percent or higher, 

pointing to a ‘‘caveat’’ in the 2019 

Guidance regarding the 90 percent 

control efficiency ‘‘off-ramp’’ that EPA 

cites in its proposal to approve. This 

‘‘caveat’’ states that EPA expects any 

FGD system installed to meet CAA 

requirements since 2007 would have an 

effectiveness of 95 percent or higher. 

NPS also points to EPA’s January 4, 

2017, Texas Best Available Retrofit 

Technology (BART) FIP in which it 

contends that EPA set a 95 percent SO2

control benchmark for deciding if a 

scrubber should be evaluated for 

upgrades or replacement. 

SO2 Control Assumptions—NPS states 

that EPA’s evaluation of SO2 removal 

efficiency at the Duke Energy EGUs 

relied on assumptions that may slightly 

overestimate scrubber efficiency. NPS 

maintains that the equation used by 

EPA to estimate uncontrolled emissions 

overestimated these emissions and the 

resulting control efficiencies. NPS 

recommends using AP–42 emission 

factors for bituminous coal, and other 

fuels, to estimate the uncontrolled 

emissions. Using the AP–42 factor for 

bituminous coal, NPS estimates that 

scrubber performance is periodically 

lower than 95 percent for DEC— 

Cliffside Unit 5, DEC—Belews Creek 

Units 1 and 2, DEP—Roxboro Units 2 

and 4A, and DEC—Marshall Units 1 and 

2 and is periodically lower than 90 

percent for units at DEP—Roxboro, 

DEC—Belews Creek, and DEC— 

Cliffside. NPS recommends reviewing 

permit limits to ensure that optimum 

scrubber performance is consistently 

achieved and to prevent backsliding. 

NOX Emissions—NPS recommends 

that EPA and North Carolina evaluate 

the NOX controls at the Duke EGUs. 

According to the NPS, replacing existing 

SNCR systems with modern SCR 

systems at DEC—Marshall (Units 1, 2, 

and 4) would be cost effective at 

$4,000–$6,000/ton and would reduce 


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92See 2019 Guidance at p. 19 (‘‘For example, it 

may be difficult to show reasonableness of a 

threshold set so high that an uncontrolled or lightly 

controlled source that is one of the largest 

contributors to anthropogenic light extinction at a 

Class I area is excluded.’’). 

93See North Carolina Duke Energy scrubber 

efficiency data file that is included in the docket for 

this action. 

94AP–42, Compilation of Air Pollutant Emissions 

Factors from Stationary Sources’’ is available at: 

https://www.epa.gov/air-emissions-factors-andquantification/ap-42-compilation-air-emissionsfactors-stationary-sources. 

95See id. at p. 24, footnote 53 (‘‘While a 90 

percent control effectiveness is used in this 

example, we expect that any FGD system installed 

to meet CAA requirements since 2007 would have 

an effectiveness of 95 percent or higher.’’). 

96See 40 CFR part 51, appendix Y—‘‘Guidelines 

for BART Determinations Under the Regional Haze 

Rule’’ (BART Guidelines). 

97See BART Guidelines at section IV.E.4 (‘‘You 

must require 750 MW power plants to meet specific 

control levels for SO2 of either 95 percent control 

or 0.15 lbs/MMBtu, for each EGU greater than 200 

MW that is currently uncontrolled unless you 

determine that an alternative control level is 

justified based on a careful consideration of the 

statutory factors.’’). 

NOX emissions by up to 5,700 tpy. 

Additionally, NPS found that 

performance of the SCR for Duke 

Energy’s EGUs have deteriorated in 

recent years. NPS recommends 

analyzing past performance as a 

potential control option for the Duke 

EGUs with SCR. 

Response 18: EPA Guidance—See 

response 4 regarding evaluation of these 

Duke Energy sources via a SO2 FFA. 

Regarding the NPS comments that the 

SO2 and NOX emissions at these Duke 

Energy EGUs have generally increased 

in recent years, which suggests that the 

controls at these facilities may not be 

operating to maintain optimum 

performance or achievable emission 

rates, North Carolina did not select 

DEC—Belews Creek, DEC—Cliffside, 

DEC—Marshall, DEP—Mayo, or DEP— 

Roxboro for an FFA because the 

visibility impacts from these sources 

were below North Carolina’s source 

selection thresholds. Because these 

sources were not selected for an FFA, 

North Carolina’s decision not to 

evaluate them for controls appears 

reasonable. 

EPA clarifies that North Carolina and 

EPA are not relying on section 2.3 

(‘‘Sources that are Not Selected Based 

on Existing Effective Controls’’) of the 

2021 Clarifications Memo and 2019 

Guidance (pp. 22–25) for DEC—Belews 

Creek, DEC—Cliffside, DEC—Marshall, 

DEP—Mayo, or DEP—Roxboro. Section 

2.3 of the 2021 Memo is applicable to 

sources that met the source selection 

criteria set by the State under the RHR 

and, instead of a FFA, the State 

provided a showing that the source has 

existing, effective controls such that a 

FFA is unlikely to result in new 

additional controls. None of these five 

Duke Energy EGUs met North Carolina’s 

source selection criteria for a FFA (i.e., 

none met or exceeded the PSAT sulfate 

or nitrate thresholds). However, in the 

NPRM (89 FR 67359), EPA evaluated 

these Duke Energy EGUs to evaluate the 

reasonableness of North Carolina’s 

source selection thresholds.92 EPA 

documented an analysis that further 

examined the Duke Energy sources to 

verify North Carolina’s claim that there 

were no uncontrolled or lightly 

controlled sources in North Carolina 

that were not selected. Regarding 

scrubber control efficiencies, in the 

NPRM (89 FR 67359), EPA provided 

data from 2017–2021 indicating that 

existing WFGD systems at the five Duke 

Energy facilities routinely achieve 92 to 

98 percent SO2 removal efficiencies. In 

this rulemaking action, EPA also 

considered data from 2022 and found 

that the Duke Energy emissions units 

have annual average scrubber removal 

efficiencies ranging between 93.8–99.2 

percent with all units having a six year 

average (2017–2022) SO2 removal 

efficiency of greater than 95 percent.93

Therefore, it appears reasonable to 

assume that an FFA would likely result 

in the conclusion that no further SO2

emissions controls (including WFGD 

upgrades) are necessary. See 89 FR 

67359. 

Regarding EPA’s potential 

overestimate of scrubber efficiency, EPA 

agrees that using the AP–42 equation 

assumption for bituminous coal 

(uncontrolled) combustion would 

slightly reduce the calculated scrubber 

efficiencies.94 However, such a small 

change in efficiency is negligible here. 

Adjusting EPA’s scrubber efficiency 

calculations would change the annual 

average efficiencies from 93.8–99.2 

percent to 93.5–99.2 percent and the 

six-year average efficiencies would still 

all be greater than 95 percent. 

Regarding NPS’ statement that FGDs 

installed after 2007 should meet a 

control effectiveness of 95 percent or 

higher,95 this is a general 

recommendation from EPA’s 2019 

Guidance that applies to states that are 

providing demonstrations that selected 

sources already have effective emission 

control technology in place and is not 

intended to be a ‘‘bright-line’’ 

recommendation. EPA disagrees that 

EPA’s January 4, 2017, Texas BART FIP 

sets a 95 percent SO2 control benchmark 

for deciding if a scrubber should be 

evaluated for upgrades or replacement. 

First, there is nothing in the RHR that 

establishes such a requirement. Second, 

the Duke Energy sources were not 

selected, and therefore, no control 

analysis was required for the second 

planning period. Additionally, the 

analysis in the first planning period 

Texas BART FIP is not relevant to the 

current situation for the North Carolina 

second planning period SIP. The Texas 

FIP examined EGU sources following 

the EPA’s first planning period BART 

Guidelines,96 which is not relevant here. 

The BART Guidelines established 

presumptive scrubber efficiencies and 

emissions rates 97 that are not a 

requirement for the second planning 

period. Also, the Texas BART FIP 

analyzed sources that either did not 

have scrubbers or were operating old 

inefficient scrubbers that only achieved 

60–80 percent SO2 efficiency. In 

addition, the Texas coal burning EGU 

sources also differed in the type of coal 

burned. All of the North Carolina EGUs 

burn bituminous coal, whereas all of the 

Texas EGUs burn low-sulfur 

subbituminous coal or lignite. 

SO2 Control Assumptions—Regarding 

NPS’ recommendations to review permit 

limits to ensure that optimum scrubber 

performance is consistently achieved 

and to prevent backsliding, as explained 

earlier, because these sources were not 

selected for an FFA, North Carolina’s 

decision not to evaluate them for 

controls appears reasonable. 

NOX Emissions—With respect to the 

recommendation that EPA require NOX

FFAs for these five Duke Energy EGUs, 

see response 3. 

Comment 19: The Organizations 

contend that the Haze Plan fails to 

reduce pollution and falls short on the 

State’s obligation to improve air quality 

for protected parks, wilderness areas, 

and communities. Additionally, they 

state that they are disappointed that 

EPA has proposed to approve this 

highly flawed and problematic plan. 

Specifically, they contend that the 

State’s plan relied on a flawed modeling 

system prepared by VISTAS. They 

contend that VISTAS modeling used 

decade-old data, does not accurately 

represent nor include NOX emissions 

contributing to haze pollution, and does 

not include many of the biggest 

polluting facilities in the state that are 

exacerbating haze pollution. 

The Organizations also contend that 

North Carolina used unreasonably high 

source selection thresholds that 

excluded Duke Energy’s coal-fired 

power plants from a full review for 

control analyses or requirements. The 

Organizations state that these Duke 

facilities are some of the biggest haze 

polluters in the State. 

The Organizations state that EPA 

shirked its duty to review North 


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98The Commenter did not define the term ‘‘soot.’’ 

EPA assumes the Commenter is referring to 

particulate matter. 

99 In table 2, the directly emitted PM species are 

coarse mass, elemental carbon, fine sea salt and fine 

soils. 

100EPA Legal Tools to Advance Environmental 

Justice (May 2022) is available at: https://

www.epa.gov/system/files/documents/2022-05/ 

EJ%20Legal%20Tools%20

May%202022%20FINAL.pdf; 2021 Clarifications 

Memo at p. 16. 

101EPA’s EJScreen tool is available at: https://

www.epa.gov/ejscreen. 

Carolina’s FFA; deferred to North 

Carolina’s highly deficient EJ analysis; 

and proposed an action that is 

inconsistent with EPA’s proposed 

disapprovals in whole or part of haze 

plans from other states such as Arizona, 

Missouri, North Dakota, Wyoming, and 

Utah. They urge EPA to issue either a 

FIP for North Carolina or a FIP for all 

states in Region 4, given that all Region 

4 states relied on VISTAS modeling that 

they contend is invalid for source 

selection. 

Response 19: Regarding the 

Organizations’ assertions related to 

VISTAS modeling, see response 1. 

Regarding the Organizations’ comments 

concerning source selection thresholds, 

see response 2. Regarding the 

Organizations’ arguments related to the 

North Carolina Duke Energy power 

plants, see response 4. Regarding the 

Organization’s comments that EPA 

neglected its duty to review the FFAs, 

see response 6. Regarding the 

Organizations’ comments about EJ, see 

response 14. Regarding the 

Organizations’ comments about a FIP, 

see response 15. 

The Organizations’ comment 

regarding rulemaking consistency is 

unclear with respect to the specific 

alleged inconsistencies between this 

action and the cited proposed actions. 

Therefore, EPA is unable to respond to 

this comment other than to note that 

EPA is now shifting from its initial 

proposal of a partial approval and 

partial conditional approval to a partial 

approval and partial disapproval. 

Comment 20: EPA received one set of 

relevant comments from a member of 

the public (hereinafter referred to as the 

‘‘Commenter’’). The Commenter states 

the national parks and forests in the 

Southern Appalachia region experience 

some of the worst air pollution in the 

country and notes that air pollution 

poses a threat to human health (e.g., 

heart attacks, heart failure, cancer, and 

respiratory diseases), especially in 

marginalized communities. The 

Commenter maintains that the RHR 

requires states to develop a plan to 

reduce anthropogenic air pollution that 

affects Class I areas, that local 

economies of communities surrounding 

Class I areas are dependent on tourism 

to these areas and contends that park 

visitation drops by eight percent when 

air quality is poor. 

The Commenter asserts that the Haze 

Plan misses opportunities to reduce 

emissions and many industrial 

pollution sources will remain 

unchecked, and that it will continue to 

allow up to 53,000 tons of haze-causing 

pollutants (SO2 and NOX) to be emitted. 

The Commenter contends that the State 

excluded ‘‘the largest and dirtiest 

sources of air pollution,’’ coal-burning 

power plants, from its plan and that the 

State also excluded two harmful air 

pollutants, soot and NOX, from 

consideration. 

The Commenter refers to EPA’s 

proposed approval as a ‘‘rubber-stamp’’ 

of North Carolina’s ‘‘do-nothing regional 

haze plan.’’ The Commenter maintains 

that North Carolina’s plan is ‘‘weak’’ 

because it is based on flawed modeling 

from VISTAS and that EPA ‘‘shirked its 

duty’’ to review the State’s sourcespecific FFAs; ‘‘incorrectly’’ allowed the 

State to exclude NOX controls in its 

FFAs; supported the State’s exclusion of 

Duke Energy’s five coal-burning power 

plants from any control analyses or 

requirements; and deferred to the State’s 

‘‘highly deficient’’ EJ analysis. The 

Commenter asserts that a weak air 

quality plan in North Carolina will 

continue to place the disproportionate 

environmental burden on black and 

low-income communities. 

Response 20: Regarding the 

Commenter’s assertions that the 

modeling from VISTAS is flawed, see 

response 1. With respect to the concern 

regarding the exclusion of NOX and 

soot 98 controls, see response 3.99

Regarding the statement that North 

Carolina excluded ‘‘Duke Energy’s five 

coal-burning power plants’’ from any 

control analyses or requirements, it is 

unclear which Duke Energy power 

plants are being referenced, however, 

should those five power plants be 

referring to DEC—Belews Creek, DEC— 

Cliffside, DEC—Marshall, DEP—Mayo, 

and DEP—Roxboro, see response 4. 

Regarding the statements that EPA 

‘‘shirked its duty’’ to review the State’s 

source-specific FFAs and that North 

Carolina’s plan is a ‘‘do-nothing regional 

haze plan,’’ see response 6. With respect 

to the EJ comments, see response 14. 

Regarding ‘‘53,000 tons of haze-causing 

pollutants (SO2 and NOX),’’ the 

Commenter did not identify the source 

of data for this figure, and thus, EPA is 

unable to respond to this aspect of the 

comment. 

III. EJ Considerations 

As explained in EPA Legal Tools to 

Advance Environmental Justice and the 

2021 Clarifications Memo, CAA section 

169A and the RHR provide states with 

the discretion to consider EJ in 

developing rules and measures related 

to regional haze.100 In this instance, 

DAQ exercised this discretion. In 

reviewing DAQ’s analysis, EPA defers to 

North Carolina’s reasonable exercise of 

its discretion in considering EJ in this 

way. The information associated with 

DAQ’s analysis is included in the NPRM 

for informational purposes only; it does 

not form any part of the basis of EPA’s 

action. 

DAQ describes North Carolina’s EJ 

Program for regional haze in section 

10.6 of the 2022 Plan which includes 

outreach plans to provide an 

opportunity for meaningful involvement 

of all people regardless of race, color, 

national origin, or income during the 

comment period of this regional haze 

plan for North Carolina. DAQ ran 

EJScreen,101 an EJ mapping and 

screening tool that provided a nationally 

consistent dataset and approach for 

combining various environmental and 

demographic indicators, around the 

North Carolina Class I areas except for 

Great Smoky Mountains because the 

area is too large to perform the EJScreen 

analysis. Based on the EJScreen results, 

which are included in appendix F–5 of 

the Haze Plan, DAQ implemented its 

outreach plan, including conducting 

specific outreach during the comment 

period on the August 30, 2021, 

proposed haze plan to communities 

within potentially underserved block 

groups that overlap or are within one 

mile of the North Carolina Class I areas. 

DAQ also provided project information 

and updates to the Eastern Band of the 

Cherokee Nation. Section IV of the 

technical support document provides a 

more detailed summary of how North 

Carolina opted to consider EJ in 

development of the 2022 Plan. While 

EPA commends North Carolina’s 

consideration of EJ when developing its 

SIP revision, the EJ analyses submitted 

by DAQ were considered but were not 

the basis for EPA’s action. 

IV. Final Action 

EPA is approving in part and 

disapproving in part North Carolina’s 

April 4, 2022, SIP submission 

addressing the regional haze 

requirements for the second planning 

period contained in 40 CFR 51.308(f). 

Specifically, EPA is approving the 

portions of the Haze Plan addressing the 

requirements of 40 CFR 51.308(f)(1), 

(f)(4) through (6), and (g)(1) through (5). 


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EPA is disapproving the portions of the 

Haze Plan addressing the requirements 

of 40 CFR 51.308(f)(2) and (3) and (i)(2) 

through (4). Thus, EPA will be obligated 

under CAA section 110(c)(1) to 

promulgate a FIP within two years after 

the effective date of this partial 

disapproval, unless the State submits, 

and EPA approves, a SIP revision that 

satisfies the requirements of 40 CFR 

51.308(f)(2) and (3) and (i)(2) through (4) 

before EPA promulgates the FIP. 

V. Statutory and Executive Order 

Reviews 

Under the CAA, the Administrator is 

required to approve a SIP submission 

that complies with the provisions of the 

Act and applicable Federal regulations. 

See 42 U.S.C. 7410(k); 40 CFR 52.02(a). 

Thus, in reviewing SIP submissions, 

EPA’s role is to review state choices, 

and approve those choices if they meet 

the minimum criteria of the Act. 

Accordingly, this final action partially 

approves and partially disapproves a 

SIP submission as meeting or not 

meeting Federal requirements, 

respectively, and does not impose 

additional requirements beyond those 

imposed by state law. 

Additional information about these 

statutes and Executive Orders can be 

found at https://www.epa.gov/lawsregulations/laws-and-executive-orders. 

A. Executive Order 12866: Regulatory 

Planning and Review and Executive 

Order 14094: Modernizing Regulatory 

Review 

This action is not a significant 

regulatory action as defined in 

Executive Order 12866, as amended by 

Executive Order 14094, and was 

therefore not subject to a requirement 

for Executive Order 12866 review. 

B. Paperwork Reduction Act (PRA) 

This action does not impose an 

information collection burden under the 

PRA because it does not contain any 

information collection activities. 

C. Regulatory Flexibility Act (RFA) 

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 because it merely partially 

approves and partially disapproves a 

SIP submission as meeting or not 

meeting Federal requirements, 

respectively. 

D. Unfunded Mandates Reform Act 

(UMRA) 

This action does not contain an 

unfunded mandate as described in 

UMRA, 2 U.S.C. 1531–1538, and does 

not significantly or uniquely affect small 

governments. The action imposes no 

enforceable duty on any state, local or 

Tribal governments or the private sector. 

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, because the SIP is not 

approved to apply on any Indian 

reservation land or in any other area 

where EPA or an Indian Tribe has 

demonstrated that a Tribe has 

jurisdiction and will not impose 

substantial direct costs on Tribal 

governments or preempt Tribal law. 

Thus, Executive Order 13175 does not 

apply to this action. 

G. Executive Order 13045: Protection of 

Children From Environmental Health 

Risks and Safety Risks 

EPA interprets Executive Order 13045 

as applying only to those regulatory 

actions that concern environmental 

health or safety risks that EPA has 

reason to believe may 

disproportionately affect children, per 

the definition of ‘‘covered regulatory 

action’’ in section 2–202 of the 

Executive Order. Therefore, this action 

is not subject to Executive Order 13045 

because it merely partially approves and 

partially disapproves a SIP submission 

as meeting or not meeting Federal 

requirements, respectively. 

Furthermore, EPA’s Policy on 

Children’s Health does not apply to this 

action. 

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 (NTTAA) 

This rulemaking does not involve 

technical standards. 

J. Executive Order 12898 and Executive 

Order 14096: Federal Actions To 

Address Environmental Justice in 

Minority Populations and Low-Income 

Populations and Revitalizing Our 

Nation’s Commitment to Environmental 

Justice for All 

Executive Order 12898 (Federal 

Actions to Address Environmental 

Justice in Minority Populations and 

Low-Income Populations, 59 FR 7629, 

February 16, 1994) directs Federal 

agencies to identify and address 

‘‘disproportionately high and adverse 

human health or environmental effects’’ 

of their actions on communities with EJ 

concerns to the greatest extent 

practicable and permitted by law. 

Executive Order 14096 (Revitalizing Our 

Nation’s Commitment to Environmental 

Justice for All, 88 FR 25251, April 26, 

2023) builds on and supplements E.O. 

12898 and defines EJ as among other 

things, the just treatment and 

meaningful involvement of all people 

regardless of income, race, color, 

national origin, or Tribal affiliation, or 

disability in agency decision-making 

and other Federal activities that affect 

human health and the environment. 

DAQ evaluated EJ considerations as 

part of its SIP submittal even though the 

CAA and applicable implementing 

regulations neither prohibit nor require 

an evaluation. EPA’s evaluation of 

DAQ’s EJ considerations are described 

above in the section titled, ‘‘EJ 

Considerations.’’ The analysis was done 

for the purpose of providing additional 

context and information about this 

rulemaking to the public, not as a basis 

of the action. EPA is finalizing action 

under the CAA on bases independent of 

North Carolina’s evaluation of EJ. Due to 

the nature of the action being taken 

here, this action is expected to have a 

neutral to positive impact on the air 

quality of the affected area. In addition, 

there is no information in the record 

upon which this decision is based that 

is inconsistent with the stated goal of 

Executive Order 12898/14096 of 

achieving EJ for communities with EJ 

concerns. 

K. Congressional Review Act (CRA) 

This action is subject to the CRA, and 

EPA will submit a rule report to each 

House of the Congress and to the 

Comptroller General of the United 

States. This action is not a ‘‘major rule’’ 

as defined by 5 U.S.C. 804(2). 

L. Petitions for 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 


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circuit by January 21, 2025. Filing a 

petition for reconsideration by the 

Administrator of this final rule does not 

affect the finality of this rule 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 section 

307(b)(2) of the CAA). 

List of Subjects in 40 CFR Part 52 

Environmental protection, Air 

pollution control, Incorporation by 

reference, Nitrogen dioxide, Particulate 

matter, Sulfur oxides. 

Dated: November 14, 2024. 

Cesar Zapata, 

Acting Regional Administrator, Region 4. 

For the reasons stated in the 

preamble, EPA amends 40 CFR part 52 

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 II—North Carolina 

■ 2. In § 52.1770, amend the table in 

paragraph (e) by adding an entry for 

‘‘Regional Haze Plan—Second Planning 

Period’’ at the end of the table to read 

as follows: 

§ 52.1770 Identification of plan. 

(e) * * * 

EPA-APPROVED NORTH CAROLINA NON-REGULATORY PROVISIONS

Provision State effective 

date 

EPA approval 

date 

Federal Register 

citation Explanation 

*******

Regional Haze 

Plan—Second 

Planning Period.

4/4/2022 11/22/2024 [Insert first page of 

Federal Register 

citation].

Approval of the portions of the Haze Plan addressing the requirements of 40 CFR 51.308(f)(1), (f)(4)–(6), and (g)(1)–(5). 

Disapproval of the portions of the Haze Plan addressing the 

requirements of 40 CFR 51.308(f)(2), (f)(3), and (i)(2)–(4). 

■ 3. Section 52.1776 is added to read as 

follows: 

§ 52.1776 Visibility protection. 

(a) Disapproval. On April 4, 2022, the 

North Carolina Department of 

Environmental Quality, Division of Air 

Quality submitted a revision to its SIP 

to address regional haze for the second 

planning period. The portions of this 

SIP revision addressing the 

requirements of 40 CFR 51.308(f)(2) and 

(3) and (i)(2) through (4) are 

disapproved. 

(b) [Reserved] 

[FR Doc. 2024–26980 Filed 11–21–24; 8:45 am] 

BILLING CODE 6560–50–P 

ENVIRONMENTAL PROTECTION 

AGENCY 

40 CFR Part 52 

[EPA–R05–OAR–2024–0184; FRL–11968– 

02–R5] 

Air Plan Approval; Wisconsin; 

Nitrogen Oxide Emissions Control 

Requirements 

AGENCY: Environmental Protection 

Agency (EPA). 

ACTION: Final rule. 

SUMMARY: The Environmental Protection 

Agency (EPA) is approving Wisconsin’s 

additions and amendments to chapters 

NR 400, NR 428, and NR 484 of the 

Wisconsin Administrative Code (Wis. 

Adm. Code). These changes clarify 

existing requirements and ensure clear 

and consistent implementation of 

Wisconsin’s control requirements for 

emissions of nitrogen oxide (NOX). EPA 

proposed to approve this action on July 

17, 2024, and received no comments. 

DATES: This final rule is effective on 

December 23, 2024. 

ADDRESSES: EPA has established a 

docket for this action under Docket ID 

No. EPA–R05–OAR–2024–0184. All 

documents in the docket are listed on 

the https://www.regulations.gov 

website. Although listed in the index, 

some information is not publicly 

available, i.e., Confidential Business 

Information (CBI), Proprietary Business 

Information (PBI), or other information 

whose disclosure is restricted by statute. 

Certain other material, such as 

copyrighted material, is not placed on 

the internet and will be publicly 

available only in hard copy form. 

Publicly available docket materials are 

available either through https://

www.regulations.gov or at the 

Environmental Protection Agency, 

Region 5, Air and Radiation Division, 77 

West Jackson Boulevard, Chicago, 

Illinois 60604. This facility is open from 

8:30 a.m. to 4:30 p.m., Monday through 

Friday, excluding Federal holidays. We 

recommend that you telephone Katie 

Mullen, at (312) 353–3490 before 

visiting the Region 5 office. 

FOR FURTHER INFORMATION CONTACT: 

Katie Mullen, Air and Radiation 

Division (AR 18J), Air and Radiation 

Division (AR18J), Environmental 

Protection Agency, Region 5, 77 West 

Jackson Boulevard, Chicago, Illinois 

60604, (312) 353–3490, 

mullen.kathleen@epa.gov. 

SUPPLEMENTARY INFORMATION: 

Throughout this document whenever 

‘‘we,’’ ‘‘us,’’ or ‘‘our’’ is used, we mean 

EPA. 

I. Background Information 

Wisconsin’s April 10, 2024, submittal 

requested that EPA approve revisions to 

NOX control requirements in chapters 

NR 400, NR 428, and NR 484 of the Wis. 

Adm. Code. Wisconsin’s proposed 

revisions clarify emission limits for 

units using more than one type of fuel, 

incorporate procedures for approving a 

site-specific emission limit alternative 

to ensure that limits are achievable in 

practice, revise and clarify existing 

compliance and monitoring 

requirements, clarify an applicability 

exception, update cross references, and 

include definitions. On July 17, 2024 

(89 FR 58097), EPA proposed to approve 

revisions to NOX control requirements 

in chapters NR 400, NR 428, and NR 484 

of the Wis. Adm. Code. Specifically, 

EPA proposed to approve Wisconsin 

rule(s) 400.03(4)(mf), 428.02(7i), 

428.02(7p), 428.02(7u), 428.02(7w), 

428.04(2)(i), 428.04(4)(c), 428.05(2)(b), 

428.05(2)(f), 428.05(3)(f), 428.05(5)(c), 

428.055, 428.07(1)(a)2, 

428.08(2)(e)(title), 428.08(2)(f)(title), 

428.08(2)(g), 428.08(3), 428.21(3)(d), 

428.22(1), 428.22(3), 428.24(1)(c), and 

484.04 Table 2 Row (15m), effective 


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