Proposed Rule2026-22063
Air Plan Approval and Air Quality Designation; TN; Attainment Plan and Redesignation of the Sullivan County Nonattainment Area for the 2010 1-Hour Primary SO2 NAAQS
Primary source
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Published
October 29, 2026
Issuing agencies
Environmental Protection Agency
Abstract
The U.S. Environmental Protection Agency (EPA or Agency) is proposing to approve the State of Tennessee's attainment plan for the Sullivan County Nonattainment Area (Sullivan County Area or Area) for the 2010 Sulfur Dioxide (SO<INF>2</INF>) National Ambient Air Quality Standards (NAAQS). Additionally, the EPA is proposing to determine that the Area has attained the 2010 SO<INF>2</INF> NAAQS and to approve Tennessee's maintenance plan for continued attainment. With these approvals, the EPA is proposing to approve Tennessee's comprehensive source-specific SO<INF>2</INF> permitted limits for two facilities in the Area, other control measures, and provisions for Reasonably Available Control Measures (RACM) and Reasonably Available Control Technology (RACT), reasonable further progress (RFP), a modeling demonstration of SO<INF>2</INF> attainment and maintenance, and to approve Tennessee's request to redesignate the Area from nonattainment to attainment of the 2010 SO<INF>2</INF> NAAQS. The EPA is taking these actions in accordance with the Clean Air Act (CAA or Act).
Full Text
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<title>Federal Register, Volume 91 Issue 208 (Thursday, October 29, 2026)</title>
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[Federal Register Volume 91, Number 208 (Thursday, October 29, 2026)]
[Proposed Rules]
[Pages 68067-68091]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2026-22063]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 52 and 81
[EPA-R04-OAR-2026-0034; FRL-13499-01-R4]
Air Plan Approval and Air Quality Designation; TN; Attainment
Plan and Redesignation of the Sullivan County Nonattainment Area for
the 2010 1-Hour Primary SO2 NAAQS
AGENCY: U.S. Environmental Protection Agency (EPA).
ACTION: Proposed rule.
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SUMMARY: The U.S. Environmental Protection Agency (EPA or Agency) is
proposing to approve the State of Tennessee's attainment plan for the
Sullivan County Nonattainment Area (Sullivan County Area or Area) for
the 2010 Sulfur Dioxide (SO<INF>2</INF>) National Ambient Air Quality
Standards (NAAQS). Additionally, the EPA is proposing to determine that
the Area has attained the 2010 SO<INF>2</INF> NAAQS and to approve
Tennessee's maintenance plan for continued attainment. With these
approvals, the EPA is proposing to approve Tennessee's comprehensive
source-specific SO<INF>2</INF> permitted limits for two facilities in
the Area, other control measures, and provisions for Reasonably
Available Control Measures (RACM) and Reasonably Available Control
Technology (RACT), reasonable further progress (RFP), a modeling
demonstration of SO<INF>2</INF> attainment and maintenance, and to
approve Tennessee's request to redesignate the Area from nonattainment
to attainment of the 2010 SO<INF>2</INF> NAAQS. The EPA is taking these
actions in accordance with the Clean Air Act (CAA or Act).
DATES: Comments must be received on or before November 30, 2026.
ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R04-
OAR-2026-0034 at <a href="http://regulations.gov">regulations.gov</a>. Follow the online instructions for
submitting comments. Once submitted, comments cannot be edited or
removed from Regulations.gov. The EPA may publish any comment received
to its public docket. Do not submit electronically any information you
consider to be Confidential Business Information (CBI) or other
information whose disclosure is restricted by statute. Multimedia
submissions (audio, video, etc.) must be accompanied by a written
comment. The written comment is considered the official comment and
should include discussion of all points you wish to make. The EPA will
generally not consider comments or comment contents located outside of
the primary submission (i.e., on the web, cloud, or other file sharing
system). For additional submission methods, the full EPA public comment
policy, information about CBI or multimedia submissions, and general
guidance on making effective comments, please visit <a href="https://www.epa.gov/dockets/commenting-epa-dockets">https://www.epa.gov/dockets/commenting-epa-dockets</a>.
FOR FURTHER INFORMATION CONTACT: Pearlene Williams-Miles, 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. The
telephone number is (404) 562-9144. Ms. Williams-Miles can also be
reached via electronic mail at <a href="/cdn-cgi/l/email-protection#13647a7f7f7a727e607e7a7f76603d637672617f767d76537663723d747c65"><span class="__cf_email__" data-cfemail="3a4d535656535b57495753565f49144a5f5b48565f545f7a5f4a5b145d554c">[email protected]</span></a>.
SUPPLEMENTARY INFORMATION: The EPA uses multiple abbreviations and
terms in this NPRM. While this list may not be exhaustive, for ease of
reading and for reference purposes, the EPA defines the following terms
and acronyms here:
AQS--Air Quality System
BART--Best Available Retrofit Technology
CAA--Clean Air Act
CBI--Confidential Business Information
CEMS--Continuous Emission Monitoring Systems
CEV--Critical Emission Value
CFR--Code of Federal Regulations
DSI--Dry Sorbent Injection
DV--Design Value
EPA--Environmental Protection Agency
FFA--Finding of Failure to Attain
FFS--Finding of Failure to Submit
FR--Federal Register
HWI--Hazardous Waste Incinerator
LTA--Longer Term Average
MMBtu--Million British Thermal Units
MOVES--EPA's Motor Vehicle Emission Simulator
MRR--Monitoring, Recordkeeping, and Reporting
NAAQS--National Ambient Air Quality Standard
NEI--National Emissions Inventory
NNSR--Nonattainment New Source Review
NPRM--Notice of Proposed Rulemaking
ppb--Parts per billion
ppm--Parts per million
PES--Permitted Emission Source
PSD--Prevention of Significant Deterioration
PTE--Potential to Emit
RACM--Reasonably Available Control Measures
RACT--Reasonably Available Control Technology
RFP--Reasonable Further Progress
SIP--State Implementation Plan
SO<INF>2</INF>--Sulfur Dioxide
TDEC--Tennessee Department of Environment and Conservation
TSD--Technical Support Document
Table of Contents
I. Executive Summary
A. What action is the EPA taking?
B. What is the legal authority and what are the requirements?
II. Background
III. Nonattainment Planning and Redesignation
A. Requirements for SO<INF>2</INF> Nonattainment Areas
B. Criteria for Redesignation
IV. Tennessee's Submissions
V. The EPA's Analysis of Tennessee's Submissions
A. Source-Specific SO<INF>2</INF> Emission Limits and Other
Control Measures
B. Nonattainment Planning Requirements
C. Redesignation Criteria
D. Public Notice and Anti-Backsliding
VI. Incorporation by Reference
VII. Statutory and Executive Order Reviews
I. Executive Summary
A. What action is the EPA taking?
The Environmental Protection Agency (EPA, or Agency) is proposing
to approve Tennessee's remaining required State Implementation Plan
(SIP) elements which provide for attainment
[[Page 68068]]
of the 2010 1-hour sulfur dioxide (SO<INF>2</INF>) National Ambient Air
Quality Standards (NAAQS). Specifically, the EPA is proposing to
approve the following elements of the Tennessee Department of
Environment and Conservation (TDEC)'s February 9, 2023, nonattainment
SIP submission: (1) Reasonably Available Control Technology (RACT) and
Reasonably Available Control Measures (RACM) determination; (2)
reasonable further progress (RFP); (3) the attainment demonstration;
(4) permanent and enforceable emission limits and other control
measures that provide for attainment of the NAAQS; \1\ and (5)
contingency measures.
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\1\ Where noted, the emission limits and control measures that
are also submitted in the June 18, 2025, submission include updates
to the emission limits or associated monitoring, recordkeeping, or
reporting, and the most up-to-date source-specific permit terms are
being proposed to be incorporated into the SIP.
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The EPA is also proposing to take the following actions addressing
the TDEC's June 18, 2025, redesignation request and SIP submission,\2\
as supplemented on January 27, 2026, and May 20, 2026, and clarified on
August 20, 2026: (1) to approve Tennessee's plan for maintaining the
2010 SO<INF>2</INF> NAAQS (maintenance plan) in the Sullivan County,
Tennessee, SO<INF>2</INF> nonattainment area (or Area), including
provisions for RACM and RACT, source-specific SO<INF>2</INF> permitted
limits, other control measures and associated monitoring,
recordkeeping, and reporting (MRR) parameters for two facilities in the
Area--Eastman Chemical (Eastman) and Primester; \3\ (2) to determine
that the Sullivan County Area has attained the 2010 SO<INF>2</INF>
NAAQS as a result of compliance with permitted limits and control
measures for Eastman and Primester; and (3) to redesignate the Sullivan
County Area to attainment for the 2010 SO<INF>2</INF> NAAQS. These
proposed actions are summarized below and are described in greater
detail throughout this Notice of Proposed Rulemaking (NPRM).
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\2\ TDEC's submission providing the redesignation request and
maintenance plan is dated June 11, 2025, under a cover letter dated
June 17, 2025. The EPA received the final package on June 18, 2025,
thus this submission is identified as TDEC's June 18, 2025,
submission throughout this proposed rulemaking.
\3\ Primester is a nearby cellulose manufacturing facility in
the Sullivan County Area southwest of Eastman. Primester operates
under the parent company, Cerdia.
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The EPA is proposing to approve Tennessee's maintenance plan for
the Sullivan County Area as meeting the requirements of section 175A of
the Act and incorporate it into the SIP. The maintenance plan is
designed to keep the Sullivan County Area in attainment of the 2010
SO<INF>2</INF> NAAQS through 2037. The June 18, 2025, submission also
includes source-specific SO<INF>2</INF> permitted limits for Eastman
and Primester, other control measures, and provisions for RACM and RACT
which are being proposed for approval and incorporation into the SIP.
The EPA is also proposing to determine that the Sullivan County
Area has met the requirements for redesignation under CAA section
107(d)(3)(E). Accordingly, the Agency is proposing to approve
Tennessee's request to change the legal designation of Sullivan County
as found at title 40 of the Code of Federal Regulations (CFR) part 81,
from nonattainment to attainment for the 2010 SO<INF>2</INF> NAAQS.
B. What is the legal authority and what are the requirements?
CAA section 110 includes relevant statutory provisions for SIP
requirements, which States develop and submit for EPA approval. Under
CAA section 110(k)(3), the EPA shall approve a SIP submission, in whole
or in part, if the submission meets all applicable requirements of the
CAA. CAA section 172 sets forth the general requirements for
nonattainment plans. CAA section 172(c) contains nine requirements for
nonattainment plan provisions.
CAA section 107(d)(3)(D) establishes the process for
redesignations. Under that provision, the EPA must approve or deny a
State's redesignation request and may redesignate a nonattainment area
to attainment only after determining that the five criteria set forth
in CAA section 107(d)(3)(E) have been satisfied. CAA section 175A(a)
requires each State submits a request under CAA section 107(d) for
redesignation of a nonattainment area to attainment to submit a SIP
revision providing for maintenance of the relevant NAAQS for at least
10 years after redesignation. Pursuant to CAA section 107(d)(3)(E)(iv),
the EPA cannot redesignate a nonattainment area to attainment unless it
has fully approved a maintenance plan for the area as meeting the
requirements of CAA section 175A.
II. Background
Under CAA section 109, the EPA has established primary and
secondary NAAQS for certain air pollutants (referred to as ``criteria
pollutants'') and conducts periodic reviews of the NAAQS to determine
whether they should be revised or whether new NAAQS should be
established. The primary NAAQS represent ambient air quality standards,
the attainment and maintenance of which the EPA has determined are
requisite to protect the public health with an adequate margin of
safety. The secondary NAAQS represent ambient air quality standards,
the attainment and maintenance of which the EPA has determined are
requisite to protect the public welfare from any known or anticipated
adverse effects associated with the presence of such air pollutant in
the ambient air.
Under the CAA, the EPA must establish NAAQS for criteria
pollutants, including SO<INF>2</INF>. SO<INF>2</INF> is released into
the atmosphere primarily through the burning of fossil fuels for power
generation and certain industrial processes. On June 22, 2010, the EPA
promulgated the revised primary SO<INF>2</INF> NAAQS, establishing a
new 1-hour primary standard of 75 parts per billion (ppb).\4\ Under the
EPA's regulations at 40 CFR part 50, the 2010 SO<INF>2</INF> NAAQS is
met at a monitoring site when the design value \5\ is less than or
equal to 75 ppb (based on the rounding convention in 40 CFR part 50,
appendix T).\6\ Ambient air quality monitoring data for the three-year
period must meet a data completeness requirement. A year meets data
completeness requirements when all four quarters are complete, and a
quarter is complete when at least 75 percent of the sampling days in
the quarter have complete data. A sampling day has complete data if 75
percent of the hourly concentration values, including State-flagged
data affected by exceptional events that have been approved for
exclusion by the Administrator, are reported.\7\
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\4\ See 75 FR 35520 (June 22, 2010).
\5\ For the 2010 SO<INF>2</INF> NAAQS, the design value is
calculated as the three-year average of the annual 99th percentile
of daily maximum 1-hour average concentrations of SO<INF>2</INF>.
\6\ See 40 CFR 50.17(b).
\7\ See 40 CFR part 50, Appendix T, section 3.1(b).
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Upon promulgation of a new or revised NAAQS, CAA section 107(d)
requires the EPA to designate as nonattainment any area that does not
meet (or that contributes to ambient air quality in a nearby area that
does not meet) the NAAQS.\8\ Effective October 4, 2013, the EPA
designated the Sullivan County Area as nonattainment based on a 2009
through 2011 three-year design value of 196 ppb from an air quality
SO<INF>2</INF> monitor operating at the time of
designation.<SUP>9 10</SUP>
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\8\ See CAA section 107(d)(1)(A)(i).
\9\ See 78 FR 47191 (Aug. 5, 2013).
\10\ Air Quality System (AQS) Site ID: 47-163-0007.
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The Sullivan County Area is comprised of a circle with a three-
kilometer (km) radius having its center at coordinates 36.5186 N;
82.5350 W, at
[[Page 68069]]
the B-253 powerhouse at Eastman in Kingsport, Tennessee, which
encompasses the SO<INF>2</INF> monitor that was operating at the time
of designation.\11\ Eastman produces organic acids, aldehydes, esters,
polymers, cellulose esters, specialty plastics, and acetate fibers, and
is the primary SO<INF>2</INF>-emitting point source located within the
Sullivan County Area. The facility also generates process steam and
electricity for most of its operations, including hazardous waste
combustion and wastewater treatment. Eastman SO<INF>2</INF> emission
sources include three powerhouses and one incinerator complex as
defined below, and several smaller emitters:
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\11\ For exact descriptions of the Sullivan County Area, refer
to 40 CFR 81.343.
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<bullet> Powerhouse B-83 consists of seven coal-fired boilers,
denoted as B-18-B-24, which provide steam for facility operations.
<bullet> Powerhouse B-253 consists of five coal-fired boilers, B-
25-B-29, which provide steam for facility operations.
<bullet> Powerhouse B-325 consists of two coal-fired boilers, B-30
and B-31, which provide steam for facility operations.
<bullet> Incinerator Complex B-248 consists of three hazardous
waste incinerators (HWIs): one liquid chemical waste incinerator, B-
248-2 (Vent A), and two rotary kilns that can burn solid or liquid
chemical waste, B-248-1 (Vents D and E).
The other SO<INF>2</INF> source within the nonattainment area is
Primester. The Primester facility consists of one main SO<INF>2</INF>
emitter--a cellulose scrap recovery process B-441-2 (Vent C).
On March 18, 2016, the EPA published a finding of failure to submit
(FFS) a complete SIP pursuant to CAA section 110(k)(1)(B)because
Tennessee had failed to submit the SO<INF>2</INF> nonattainment SIP by
the submission deadline of April 4, 2015.\12\ Tennessee was required to
address the Sullivan County Area's nonattainment area planning
obligations by this deadline to demonstrate it would attain the NAAQS
no later than the October 4, 2018, statutory attainment date.\13\ This
finding initiated a deadline of October 18, 2017, under CAA section
179(a), for the imposition of offset and highway funding sanctions
unless Tennessee submitted a complete SIP and the EPA deemed it
complete by that date. Additionally, under CAA section 110(c), the
finding triggered a requirement that the EPA promulgate a Federal
Implementation Plan within two years of the finding's effective date
(i.e., April 18, 2018) unless Tennessee submitted, and the EPA
approved, the required SIP submission by that date. On May 12, 2017,
Tennessee submitted a nonattainment SIP with a modeled attainment
demonstration (first nonattainment SIP).\14\ On October 10, 2017, the
EPA determined that Tennessee's May 12, 2017, nonattainment SIP was
complete pursuant to 40 CFR part 51, appendix V; thus, the CAA section
179(a) sanctions were not imposed.
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\12\ See 81 FR 14736 (Mar. 18, 2016).
\13\ See Id. The FFS, effective April 18, 2016, found that 16
nonattainment areas in 11 States, which included Sullivan County,
Tennessee, had failed to submit the required SO<INF>2</INF>
nonattainment SIPs.
\14\ Tennessee's May 12, 2017, nonattainment SIP was submitted
with a cover letter dated May 11, 2017. In Tennessee's redesignation
request, TDEC refers to this nonattainment SIP with the May 11,
2017, date.
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The EPA proposed to approve Tennessee's May 12, 2017, nonattainment
SIP for the Sullivan County Area on June 29, 2018, and received adverse
comments.<SUP>15 16</SUP> Subsequently, in 2019, ambient monitors in
the Area recorded exceedances of the 2010 SO<INF>2</INF>, and in
response, Eastman developed and implemented operational changes as
necessary to prevent future monitored violations.
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\15\ See 83 FR 30609 (June 29, 2018).
\16\ The EPA finalized only the portions of the attainment plan
that consisted of the emissions inventory and nonattainment new
source review requirements of 172(c)(3) and (5), respectively, for
which the Agency did not receive adverse comments in the June 29,
2018, NPRM. Tennessee withdrew the remaining portions of the May 12,
2017, attainment demonstration from EPA consideration on April 29,
2025, in a letter dated April 28, 2025, thus the EPA has no further
obligation to act on the May 12, 2017, attainment demonstration.
This letter is included in the docket for this action.
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The EPA was subsequently sued by the Center for Biological
Diversity, the Center for Environmental Health, and the Sierra Club
\17\ for not determining whether the Sullivan County Area attained the
2010 SO<INF>2</INF> standard by the October 4, 2018, statutory
attainment date.\18\ On June 25, 2021, the EPA entered into a consent
decree requiring the Agency to finalize by March 31, 2022, a
determination as to whether the Sullivan County Area had attained the
1-hour SO<INF>2</INF> standard by the October 4, 2018, attainment date.
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\17\ Center for Biological Diversity et al. v. Regan; Case No.
3:20-cv-05436-EMC (N.D. Cal.).
\18\ Under CAA section 179(c), within six months of the
attainment date, the EPA is required to determine based on the
area's air quality as of the attainment date, whether an area
attained by the attainment date. If the EPA determines that an area
failed to attain by the attainment date, the Agency is required to
publish the determination in the Federal Register pursuant to CAA
section 179(c)(2).
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For the Area to have attained the 2010 SO<INF>2</INF> NAAQS by the
October 4, 2018, attainment date, the 1-hour SO<INF>2</INF> design
value needed to be equal to or less than 75 ppb for the 1-hour standard
based upon an available quality-assured and certified air quality
monitoring data from January 2015 through December 2017 at each
eligible monitoring site. On April 5, 2022, the EPA finalized a finding
of failure to attain (FFA) for the Sullivan County Area, effective May
5, 2022, in which the Agency determined that the Area did not attain
the 1-hour SO<INF>2</INF> standard by October 4, 2018.\19\
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\19\ See 87 FR 19645 (Apr. 5, 2022).
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The EPA's FFA triggered a requirement pursuant to CAA section
179(d) for Tennessee to submit to the EPA a revised nonattainment SIP
for the Sullivan County Area, within one year of the FFA publication in
the Federal Register (i.e., by April 5, 2023), that provided for
attainment of the 2010 SO<INF>2</INF> standard as expeditiously as
practicable but no later than five years from the FFA's Federal
Register publication date (i.e., April 5, 2027).
In response to the EPA's April 5, 2022, FFA, TDEC submitted a
revised nonattainment SIP (second nonattainment SIP) on February 9,
2023, which provided for modeled attainment of the 2010 SO<INF>2</INF>
NAAQS based on enforceable control measures for the three coal-fired
boilers at Eastman established in SIP operating permit No. 080222.
Additionally, the February 9, 2023, nonattainment SIP included existing
SO<INF>2</INF> emission limits for other Eastman sources and Primester
as measures to be adopted into the SIP.
On June 18, 2025, TDEC submitted a request to the EPA to
redesignate the Sullivan County Area from nonattainment to attainment,
with an accompanying SIP revision consisting of a maintenance plan for
the Area. The submission also included source-specific SO<INF>2</INF>
permitted limits for two facilities in the Area, other control
measures, and provisions for RACM and RACT that are being proposed for
approval and incorporation into the SIP. Tennessee supplemented the
June 18, 2025, submission on January 27, 2026 and May 20, 2026,
providing corrections and clarifications to portions of the SIP
narrative and attachments and further clarified its submission via
email on August 20, 2026. The EPA is proposing to approve elements of
Tennessee's February 9, 2023, second nonattainment SIP and Tennessee's
June 18, 2025, submission, as supplemented on January 27, 2026 and May
20, 2026, and clarified on August 20, 2026, as discussed in further
detail below.
[[Page 68070]]
III. Nonattainment Planning and Redesignation
A. Requirements for SO2 Nonattainment Areas
All States must submit SIPs or SIP revisions to show they have the
basic air quality management program components in place to implement a
new or revised NAAQS, as specified in CAA section 110(a)(1). These
plans are called ``infrastructure SIPs.'' For areas designated
nonattainment for a specific NAAQS, States must also submit
``nonattainment plans'' that outline strategies and emissions control
measures and demonstrate how the area will improve in air quality as
well as attain and maintain the NAAQS.\20\
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\20\ See CAA section 172(c).
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Under CAA sections 110(a)(1) and (2), States are required to submit
``infrastructure SIPs'' to ensure that they have the basic air quality
management program components in place to provide for implementation,
maintenance, and enforcement of the NAAQS, including the 2010 1-hour
SO<INF>2</INF> NAAQS. The EPA approved Tennessee's infrastructure SIP
for the 2010 1-hour SO<INF>2</INF> NAAQS.\21\ For the 2010 1-hour
SO<INF>2</INF> NAAQS, Tennessee's infrastructure SIP addressed CAA
sections 110(a)(2)(A) through (H) and (J) through (M), except
110(a)(2)(C) to the extent that subsection refers to a permit program
as required in part D, title I of the CAA, i.e., nonattainment new
source review (NNSR). CAA sections 110(a)(2)(I) and (K), which
specifically address the nonattainment plan provisions, are addressed
in section V.B of this NPRM.
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\21\ See 81 FR 85410 (Nov. 28, 2016), 83 FR 48237 (Sept. 24,
2018), and 88 FR 53800 (Aug. 9, 2023).
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CAA section 110(l) contains two main provisions applicable to SIPs,
including nonattainment plans. First, CAA section 110(l) requires that
each SIP revision submitted by a State must be adopted by a State after
reasonable notice and public hearing. Second, under CAA section 110(l),
the EPA may not approve a SIP if it would interfere with any applicable
requirement concerning NAAQS attainment, reasonable further progress
toward attainment, or any other applicable requirement of the CAA. For
the reasons discussed in section V.D of this NPRM, the EPA is proposing
that Tennessee has met these requirements.
Nonattainment plans must meet the applicable requirements of the
CAA, specifically CAA title I, section 110 and part D. To address plan
requirements for nonattainment areas, there are two elements of CAA
section 110(a)(2) pertaining to part D in title I of the CAA that are
outside the scope of infrastructure SIPs. The first is CAA section
110(a)(2)(C) to the extent it refers to NNSR under part D of title I of
the CAA, and the second is CAA section 110(a)(2)(I) in its
entirety.\22\ For the first of these two elements, the EPA approved
Tennessee's SIP revisions comprising the State's rules for NNSR most
recently on July 30, 2012.\23\ For the second of these two elements,
the EPA's ``SIP Lean Toolkit for Collaboration Between EPA and Air
Agencies,'' December 6, 2019 (2019 SIP Lean Toolkit) \24\ identifies
CAA sections 172, 191, and 192 as the applicable planning requirements
specific to SO<INF>2</INF> nonattainment areas.
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\22\ See Guidance on Infrastructure State Implementation Plan
(SIP) Elements under Clean Air Act Sections 110(a)(1) and 110(a)(2);
EPA, Sep. 13, 2013, can be found at <a href="https://www.epa.gov/sites/default/files/2015-12/documents/guidance_on_infrastructure_sip_elements_multipollutant_final_sept_2013.pdf">https://www.epa.gov/sites/default/files/2015-12/documents/guidance_on_infrastructure_sip_elements_multipollutant_final_sept_2013.pdf</a> at p. 4, available in the docket for this action.
\23\ See 77 FR 44481 (July 30, 2012).
\24\ <a href="https://www.epa.gov/sites/default/files/2019-12/documents/sip_lean_toolkit_for_collaboration_between_epa_and_air_agencies.pdf">https://www.epa.gov/sites/default/files/2019-12/documents/sip_lean_toolkit_for_collaboration_between_epa_and_air_agencies.pdf</a>
at pp. 22-23.
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In areas designated as nonattainment for a particular NAAQS, CAA
section 172 includes nonattainment plan provisions that require States
to submit SIPs that demonstrate the affected area will attain the
relevant NAAQS as expeditiously as practicable, but no later than the
applicable statutory attainment date. To support such an attainment
demonstration for SO<INF>2</INF> nonattainment plans, the EPA's 2019
SIP Lean Toolkit specifies the applicable provisions of the CAA as
sections 172(a)(2), (b), (c)(1) through (c)(6), and (c)(9). As
discussed in section V.B of this NPRM, the EPA is proposing to find
that Tennessee's 2023 second nonattainment plan meets each of these
applicable provisions of CAA section 172.
CAA section 191(a) directs States to submit SIPs to the EPA for
areas designated as nonattainment with respect to the primary NAAQS for
sulfur oxides, nitrogen dioxide, or lead within 18 months of the
effective date of the designation. As noted above, on March 18, 2016,
the EPA determined that Tennessee failed to submit a complete SIP
within 18 months of the effective designation of the Sullivan County
Area to nonattainment. TDEC initially submitted a May 12, 2017,
attainment SIP following the FFS. CAA section 192(a) requires that SIPs
for nonattainment areas must provide for attainment of the relevant
NAAQS as expeditiously as practicable, but no later than five years
from the effective date of the nonattainment designation. However, on
April 5, 2022, the EPA determined that the State failed to attain by
the applicable attainment date, triggering a requirement under CAA
section 179(d) to submit a SIP revision by April 5, 2023 including
``such additional measures as the Administrator may reasonably
prescribe, including all measures that can be feasibly implemented in
the area in light of technological achievability, costs, and any nonair
quality and other air quality-related health and environmental
impacts'' and which would provide for attainment by April 5, 2027.\25\
As discussed in section V.B of this NPRM, Tennessee's 2023 second
nonattainment SIP includes an attainment demonstration for the Sullivan
County Nonattainment Area that demonstrated attainment of the 2010 1-
hour SO<INF>2</INF> NAAQS as expeditiously as practicable, by the date
of the June 18, 2025, redesignation request and maintenance plan, and
in less than five years from the Apri 5, 2022, publication date.
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\25\ The EPA did not prescribe additional measures under CAA
section 179(d)(2) at the time of the finding.
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B. Criteria for Redesignation
The CAA provides the requirements for redesignating a nonattainment
area to attainment. Specifically, CAA section 107(d)(3)(E) allows for
redesignation provided that: (1) the Administrator determines that the
area has attained the applicable NAAQS; (2) the Administrator has fully
approved the applicable implementation plan for the area under CAA
section 110(k); (3) the Administrator determines that the improvement
in air quality is due to permanent and enforceable reductions in
emissions resulting from implementation of the applicable SIP and
applicable Federal air pollutant control regulations, and other
permanent and enforceable reductions; (4) the Administrator has fully
approved a maintenance plan for the area as meeting the requirements of
CAA section 175A; and (5) the State containing such an area has met all
requirements applicable to the area for the purposes of redesignation
under CAA section 110 and part D.
IV. Tennessee's Submissions
Tennessee's February 9, 2023, second nonattainment SIP includes:
(1) RACT and RACM determinations; (2) reasonable further progress
(RFP); (3) a base year nonattainment inventory; (4) a projected
attainment year inventory; (5) the attainment demonstration; (6)
permanent and enforceable emission limits and other control measures
that provide for attainment of the NAAQS;
[[Page 68071]]
and (7) contingency measures. Tennessee's June 18, 2025, submission
includes a request for the EPA to redesignate the Sullivan County Area
to attainment for the 2010 SO<INF>2</INF> NAAQS and to approve the
associated SIP revision containing a maintenance plan for the Area. The
submission also requests that the EPA adopt into the SIP source-
specific SO<INF>2</INF> permit limits, other control measures, and
associated MRR compliance parameters for Eastman and Primester, as well
as RACT and RACM provisions for the Area.\26\
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\26\ See section V.A below.
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As noted previously, on January 27, 2026 and May 20, 2026, TDEC
transmitted to the EPA supplements to the June 18, 2025, submission
that make corrections and clarifications to portions of the SIP
narrative and attachments, including to SIP operating permit No. 082237
in Attachment J1 of the June 18, 2025, submission and further clarified
its submission in an email on August 20, 2026.
The January 27, 2026, supplement revises the Description of
Monitoring Protocol (Monitoring Protocol) for Eastman B-248 HWIs at
Appendix 5 of SIP operating permit No. 082237 to establish a
practicably enforceable process to obtain monitoring values and
demonstrate compliance with the modeled SO<INF>2</INF> emission limit.
The revised Monitoring Protocol was established in Appendix 1 of a new
SIP operating permit No. 083740 that TDEC issued on January 14,
2026.\27\ See section V.A.5 below for additional discussion of the
parametric monitoring changes established in SIP operating permit No.
083740 for Eastman's HWI.\28\
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\27\ See the January 27, 2026, supplement in the docket for this
NPRM.
\28\ Parametric monitoring is a common method to ensure
continuous compliance with an emissions limit in lieu of continuous
direct sampling/monitoring of the subject pollutant, in this case
SO<INF>2</INF>. This is a common regulatory approach used in various
federal regulations such as the Maximum Achievable Control
Technology and New Source Performance Standards. In parametric
monitoring, certain performance parameters that are critical to the
proper operation of the emission control device are continuously
monitored. These parameters can include scrubber recirculation flow,
pH, and pressure drop. The compliance parameter minimum levels are
typically established during emission source testing to ensure
operating at those parameter levels meets the underlying emission
control requirement.
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On May 20, 2026, Tennessee submitted a second supplement correcting
portions of the State's 2025 redesignation request and maintenance plan
narrative, attachments, and SIP operating permit No. 082237.\29\ The
following discussion summarizes the corrections and clarifications to
TDEC's SIP narrative and attachments.
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\29\ See SIP permit #083740 in TDEC's January 27, 2026,
supplement in the docket for this NPRM.
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The May 20, 2026, supplement adds a detailed discussion and Table
4: SO<INF>2</INF> Emissions from Batch Chemical Manufacturing (MSOP-25,
Permitted Emission Source (PES) OC-BATCH) in Section 2.2 (Air Quality
Modeling) of the redesignation request and maintenance plan submission
that explains the State's rationale to consider Eastman's batch
specialty chemical operations as an intermittent emissions source and
exclude it from the redesignation SIP modeling analysis.
The supplement narrative includes Table 2, which provides changes
to Table 2-7 (Summary of Model Results) of the redesignation request
and maintenance plan submission and lists the maximum modeled
concentration for each air dispersion model run. The original Table 2-7
in the June 18, 2025, submission did not fully summarize the results of
all the model runs performed by Tennessee. The supplement replaces
Table 2-7 with a comprehensive list of all modeling run results in
Table 2: Summary of Model Results (Updated Version of Table 2-7 of the
June 18, 2025, submission) and Table 3: Description of Critical Model
Runs. Table 2 also includes the latitude, longitude, and distance to
the nearest monitor for all of Tennessee's model runs.
The supplement provides a longer term averaging (LTA) discussion
for the B-351 coal-gasification flare, including a summary of the
actual flare emissions for 2019 through 2021 listed in Table 1. The new
discussion explains the State's procedures and rationale for
calculating the 30-day rolling average 14.6 pounds per hour (lb/hr)
SO<INF>2</INF> emission limit that TDEC requested the EPA adopt into
the SIP as a permanent control measure in the June 18, 2025, submission
(see section 4.0). Attachment D of the supplement includes a revised
spreadsheet of hourly flare emissions data that shows the frequency
over the critical emission value (16.28 lb/hr) for calendar years 2019
and 2020.
Table 4-4 of the June 18, 2025, submission and TDEC's August 20,
2026, email clarify the list of the specific emission limits Tennessee
requests that the EPA adopt into the SIP as permanent emission
reduction measures. The supplement corrects the numerical
SO<INF>2</INF> emission limit for the B-351 coal gasification flare
from 16.28 lb/hr to 14.6 lb/hr in section 4 of the narrative. The
revised Table 4-4 in Attachment C of the supplement replaces the
original Table 4-4 in the June 18, 2025, submission.\30\ TDEC also
replaces the numerical limit in SIP permit No. 082237 (see discussion
below).
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\30\ See a redline version of Table 4-4 in Attachment C of
TDEC's May 20, 2026, supplement.
---------------------------------------------------------------------------
The supplement also corrects an entry in the June 18, 2025,
submission for Table 4-3 (Calculation of 30-Day Rolling Average
Emission Limit, Coal Gasification Flare). Although Table 4-3 was
referenced in the narrative table of contents during the drafting
process, the flare discussion was moved to Attachment I prior to public
participation and Board approval. As a result, Table 4-3 was missing
from the June 18, 2025, submission, and the supplement includes this
Table as Table 11-2 of Attachment II: Modeling of Flare Actual
Emissions.
The supplement also revises the contingency measure trigger
language in section 6 of the June 18, 2025, submission narrative to add
the phrase ``any calendar year'' before the phrase ``during the
maintenance period'' to clarify a full system audit is required if a
monitor in the maintenance area records four exceedances in any
calendar year within the maintenance period. The supplement also
corrects the citation to CAA section 172(c)(9) by replacing it with a
citation to section 175A in section 6 of the narrative.
The following discussion summarizes corrections and clarifications
to SIP operating permit No. 082237 (Amendment #1) in TDEC's May 20,
2026, supplement to the June 18, 2025, submission. The revisions to the
contingency measure language including the CAA section 175A citation in
section 6.0 of the narrative discussed above is also updated in the SIP
permit contingency measure at Condition G4. Condition S3-1 is revised
to add the 14.6 lb/hr numerical SO<INF>2</INF> emission limit for the
B-351 coal gasification flare at new subparagraph B (see section V.A.6
of this NPRM) and clarify that Conditions S3-1 A and C, along with
Compliance Method B, are not requested for incorporation into the SIP.
Appendix 3 of the permit is revised to clarify the Monitoring Protocol
and compliance method to calculate the SO<INF>2</INF> emissions for the
B-351 coal gasification flare. Finally, the supplement clarifies that
SIP permit No. 083740 supersedes the revised permit No. 082237 for the
B-248 HWIs.
V. The EPA's Analysis of Tennessee's Submissions
In accordance with the CAA, the EPA is proposing to approve
elements of Tennessee's February 9, 2023, second
[[Page 68072]]
nonattainment SIP. The EPA is also proposing to approve Tennessee's
June 18, 2025, submission, as supplemented on January 27, 2026, and May
20, 2026, and as clarified on August 20, 2026, for the 2010
SO<INF>2</INF> NAAQS. In this section of the NPRM, the EPA analyzes the
source-specific SO<INF>2</INF> emission limits, other control measures,
and MRR compliance parameters the State requested that the EPA approve
into the SIP from the February 9, 2023, submission and June 18, 2025,
submission, as supplemented, and the consistency of the June 18, 2025,
submission, as supplemented, with the five redesignation criteria
provided under CAA section 107(d)(3)(E) (section V.C).
A. Source-Specific SO2 Emission Limits and Other Control Measures
TDEC's February 9, 2023, submission requests that the EPA
incorporate measures into the SIP that provide for attainment, thereby
making them permanent and enforceable. TDEC's June 18, 2025, submission
requests that the EPA redesignate the Sullivan County Area from
nonattainment to attainment based, in part, on the implementation of
new enforceable SO<INF>2</INF> emission reducing control measures and
existing limits for the primary SO<INF>2</INF> sources in the Area. The
June 18, 2025, submission also resubmits the SO<INF>2</INF> emission
reducing control measures and existing emission limits from the
February 9, 2023, submission, in some cases with updated emission
limits or revised associated MRR. Additionally, some of these control
measures and limits are already incorporated into Tennessee's SIP.\31\
For the remaining control measures and limits relied upon for
demonstrating attainment and meeting the nonattainment SIP
requirements, Tennessee's February 9, 2023, submission requests that
the EPA make these enforceable SO<INF>2</INF> emission limits, other
control measures, and MRR compliance parameters permanent via
incorporation into the SIP for Eastman's coal-fired boilers and other
significant SO<INF>2</INF>-emitting sources at Eastman established in
SIP operating permit No. 080222 and prevention of significant
deterioration (PSD) permits Nos. 955272F and 966859F, and for the
nearby source, Primester, in title V operating permit No. 574994.
Tennessee's June 18, 2025, submission requests that the EPA incorporate
the SO<INF>2</INF> emission limits, other control measures, and MRR
compliance parameters into the SIP for Eastman's coal-fired boilers and
other significant SO<INF>2</INF> emitting sources at Eastman that have
significantly reduced SO<INF>2</INF> emissions in the Sullivan County
Area, resulting in monitored and modeled attainment of the 2010
SO<INF>2</INF> standard, as well as existing emission limits for other
process emission sources at Eastman and for the nearby source,
Primester. Specifically, the June 18, 2025, submission, as
supplemented, requests that the EPA incorporate emission limits and
control measures and associated MRR for: Eastman's SIP operating permit
No. 082237 (Amendment #1), which supersedes SIP operating permit No.
080222; Eastman's SIP operating permit No. 083740, which supersedes SIP
operating permit No. 082237 for specific emission units; Eastman's PSD
construction permits Nos. 955272F and 966859F; and Primester's title V
operating permit No. 574994.\32\
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\31\ See Table 1A, below, for a list of permanent and
enforceable control measures incorporated into the SIP.
\32\ See Table 1B, below, for a list of control measures
proposed to be incorporated into the SIP.
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As discussed above in section II, Eastman is the primary
SO<INF>2</INF> emitting point source located within the Sullivan County
Area. The enforceable control measures are responsible for reducing
SO<INF>2</INF> emissions at Eastman by approximately 85 percent and a
significant decrease in ambient SO<INF>2</INF> monitored concentrations
within the Area to support the State's request to redesignate the area
based on permanent and enforceable measures. Additionally, the
SO<INF>2</INF> emissions from Primester were assessed for any potential
contribution to monitored and modeled violations of the 1-hour
standard.
Section 4 of the February 9, 2023, submission and Section 4 of the
June 18, 2025, submission discuss the enforceable control measures
implemented at Eastman's coal-fired boilers, HWIs, coal gasification
flares, and other existing emitting sources, and at Primester. Table 4-
4 in the submission lists the specific numerical SO<INF>2</INF>
emission limits and/or qualitative control measures; the enforceable
permits authorizing the measures and the associated conditions for each
permit and source emission unit; and the MRR compliance parameters for
sources at Eastman and Primester for incorporation into the
SIP.<SUP>33 34</SUP> As discussed in this section of the NPRM, the EPA
incorporated some of these permit conditions into the SIP after June
18, 2025.
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\33\ A copy of each enforceable permit initially requested for
incorporation into the SIP in the February 9, 2023, submission is
provided in Attachment I of that submission.
\34\ A copy of each enforceable permit is provided in Attachment
J of the June 18, 2025, submission, Attachment A of the January 27,
2026, supplement, Attachments A and B of the May 20, 2026,
supplement, or Attachment I of the February 9, 2023, submission
included in the docket of this NPRM.
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On January 27, 2026, Tennessee provided a supplement to the June
18, 2025, submission. This supplement contains operating permit No.
083740, which supersedes operating permit No. 082237 in the June 18,
2025, submission only for Eastman's HWIs B-248-1 and 248-2 and modifies
the Monitoring Protocol and compliance methodology for these units at
Appendix 1 of the permit. On May 20, 2026, Tennessee submitted an
additional supplement to the June 18, 2025, submission. This supplement
contains modifications to the contingency measure trigger language and
CAA citation in the June 18, 2025, submission narrative and contains
operating permit No. 082237 (Amendment #1), which modifies the
contingency measure provision at Condition G4, corrects the numerical
emission limit for the B-351-5 coal gasification flares at Condition
S3-1, and updates the Monitoring Protocol in Appendix 3 to clarify the
frequency of emission calculations.
Tennessee's June 18, 2025, submission relies on emission reduction
control measures and enforceable emission limits for primary
SO<INF>2</INF> emitting sources at Eastman (B-253, B-83, B-325, and B-
248 and other process units discussed below) and nearby sources. The
submission includes modeling that demonstrates the Sullivan County Area
has attained and will maintain the SO<INF>2</INF> NAAQS through
compliance with these multi-unit permit limits and control measures.
The modeling demonstration included in the June 18, 2025, submission is
the same modeling included in the February 9, 2023, nonattainment SIP
submission. Additionally, the June 18, 2025, submission includes
operating permit No. 082237, which includes emission limits, other
control measures, and compliance parameters for the Eastman primary
SO<INF>2</INF> sources first established in SIP operating permit No.
080222 (issued March 1, 2023) included in Tennessee's February 9, 2023,
nonattainment SIP submission for the Sullivan County Area.\35\
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\35\ SIP operating permit No. 080222 establishes SO<INF>2</INF>
control measures and MRR parameters to demonstrate modeled
attainment of the Sullivan County Area by the 2027 attainment date.
See below.
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On December 11, 2025, the EPA approved the State's February 23,
2022, regional haze SIP for the second planning period and incorporated
into Tennessee's SIP certain conditions from SIP operating permit No.
080222 and title V operating permit No. 576501
[[Page 68073]]
submitted with Tennessee's February 9, 2023, nonattainment SIP
submission.<SUP>36 37 38</SUP> Specifically, the EPA approved the
following SO<INF>2</INF> control measures and compliance parameters for
Eastman's coal-fired boilers B-83 and B-325 from SIP operating permit
No. 080222 and title V operating permit No. 576501:
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\36\ See 90 FR 57367 (Dec. 11, 2025).
\37\ On December 20, 2024, Tennessee submitted a letter to EPA
asking the Agency to incorporate certain existing SO<INF>2</INF>
control measures from the permit for Eastman coal-fired Boilers 21,
22, 30 and 31 with the February 23, 2022, regional haze SIP to
generally strengthen Tennessee's SIP as part of the Agency's
approval of the regional haze SIP. See Document ID EPA-R04-OAR-2019-
0308-0070 at <a href="http://www.regulations.gov">www.regulations.gov</a>.
\38\ Tennessee's February 9, 2023, nonattainment SIP operating
permit No. 080222 and the June 18, 2025, submission operating permit
082237, establish identical enforceable SO<INF>2</INF> control
measures for Eastman sources, except in the case of the B-351-5 coal
gasification flare as mentioned below. Thus, the numerical
SO<INF>2</INF> emission limits, control measures, and MRR for
Eastman's coal-fired boilers at Powerhouses B-83 and B-325
established in operating permit 082237 are permanent and enforceable
through the approval of certain permit conditions from SIP operating
permit No. 080222 with the February 23, 2022, regional haze SIP. See
90 FR 57367 (Dec. 11, 2025).
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<bullet> From permit No. 080222: the portion of Condition 1
containing the 30-day rolling average SO<INF>2</INF> emission limit of
1,248 lb/hr for Eastman Boilers 18 through 24, 30, and 31; all of
Condition 2; the portion of Condition 3 containing compliance
parameters for the 1,248 lb/hr SO<INF>2</INF> limit; and Attachment A.
<bullet> From permit No. 576501: all of Conditions E3-8 and E3-9,
which include the 317 lb/hr and 293 lb/hr individual SO<INF>2</INF>
limits applicable to Boilers 30 and 31, respectively, at B-325;
Condition E3-20; and Attachment 3.\39\
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\39\ See 90 FR 57367 (Dec. 11, 2025).
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These control measures, emission limits, and compliance parameters
were established and/or incorporated into enforceable permits governed
by Tennessee's federally enforceable permit regulations.\40\ Below is a
summary of the federally enforceable permits for emission sources at
Eastman and Primester that establish control measures responsible for
improvement in air quality in the Sullivan County Area and support
Tennessee's 2025 request to redesignate the area to attainment.
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\40\ See Tennessee Air Pollution Control Regulations (TAPCR)
Chapter 1200-03-09 as SIP-approved at <a href="https://www.epa.gov/air-quality-implementation-plans/tennessee-air-pollution-control-regulations-chapter-1200-3-9">https://www.epa.gov/air-quality-implementation-plans/tennessee-air-pollution-control-regulations-chapter-1200-3-9</a>.
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<bullet> Eastman SIP operating permit No. 080222 \41\--Issued March
1, 2023, this permit established enforceable SO<INF>2</INF> emission
limits (Condition 1), control measures (Conditions 2 and 4), and MRR
parameters (Condition 3) for Eastman SO<INF>2</INF> emission sources B-
83, B-235, B-248, B-334-1, B-351-5, and B-55-1, effective September 1,
2023. This permit was submitted with Tennessee's February 9, 2023,
nonattainment SIP for the Sullivan County Area to demonstrate that the
Area would attain the 2010 SO<INF>2</INF> standard by the April 5,
2027, attainment date based on modeling of the Eastman enforceable
emission limits and control measures. As mentioned above, on December
11, 2025,\42\ the EPA incorporated into the Tennessee SIP portions of
permit No. 080222 relating to those enforceable SO<INF>2</INF> limits
and MRR parameters at the same time that it approved the State's
regional haze SIP for the second planning period. See Table 1A, below,
for the list of permit conditions previously incorporated into the SIP.
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\41\ A copy of SIP operating permit No. 080222 is included in
the docket for this NPRM.
\42\ See 90 FR 57367 (Dec. 11, 2025) and Docket ID: EPA-R04-OAR-
2019-0308.
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<bullet> Eastman title V operating permit 576501 \43\--Issued May
15, 2020, this permit requires Eastman to operate the two coal-fired
boilers at B-325 (Boilers B-30 and B-31), in accordance with the
individual emission limits and monitoring requirements established in
Conditions E3-8 and E3-9. This title V permit incorporates the
individual SO<INF>2</INF> emission limits from Eastman PSD permit
955272F.\44\ As mentioned above, on December 11, 2025,\45\ the EPA
incorporated into the Tennessee SIP portions of permit No. 080222 at
the same time that it approved the State's regional haze SIP for the
second planning period. See Table 1A, below, for the list of permit
conditions incorporated into the SIP.
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\43\ A copy of title V operating permit No. 576501 was submitted
as part of Tennessee's December 20, 2024, supplemental letter, and
is included in the docket for this NPRM. See supra Footnote 39.
\44\ The EPA is not proposing to approve into the SIP the
remaining SO<INF>2</INF> emission limits for Eastman units
established in Eastman SIP Operating Permit No. 080222 as these
limits and MRR parameters are included in Eastman SIP Operating
Permit No. 082237 submitted with TDEC's June 18, 2025,
redesignation, which supersedes SIP Operating Permit No. 080222.
\45\ See 90 FR 57367 (Dec. 11, 2025) and Docket ID: EPA-R04-OAR-
2019-0308.
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<bullet> Eastman SIP operating permit No. 082237 \46\--Issued June
11, 2025, and submitted with Tennessee's June 18, 2025, submission,
this permit adds periodic reporting requirements but contains the same
SO<INF>2</INF> emission limits, control measures, and monitoring
requirements from SIP operating permit No. 080222 for boilers at B-83,
B-325, B-55, B-351, B-334 and B-248, effective September 1, 2023,
except for the coal gasification flare B-351-5. This permit also
establishes general permit conditions for recordkeeping and contingency
measures at Condition G2 and G4 and separate recordkeeping and
reporting conditions for all Eastman boilers. This permit was submitted
to support Tennessee's redesignation of the Sullivan County Area from
nonattainment to attainment based on modeling that included these,
among other, enforceable control measures and an attaining three-year
design value for the period 2020-2022. A modification to SIP operating
permit No. 082237,\47\ referred to as 082237 (Amendment #1), was issued
May 13, 2026, and submitted with Tennessee's May 20, 2026, supplement
which corrects administrative errors and clarifies conditions for
portions of the June 11, 2025, permit. Specifically, the modification
corrects the SO<INF>2</INF> emission limit for the B-351-5 coal
gasification flare from 16.28 lb/hr to 14.6 lb/hr at Condition S3-1 and
updates the flare's Monitoring Protocol and compliance method at
Appendix 3 to clarify that Eastman's Distributed Control System
calculates the flare SO<INF>2</INF> emissions automatically each hour.
This permit also corrects the primary trigger language and a CAA
citation for the enforceable contingency measures at Condition G4.
Finally, the supplement clarifies that the Monitoring Protocol for the
B-248 HWIs at Condition S5-1 and Appendix 5 is superseded by the SIP
permit No. 083740 (issued and effective January 14, 2026, and submitted
with the January 27, 2026, supplement). Amendments to SIP permit No.
082237 became effective May 13, 2026, through SIP permit No. 082237
(Amendment #1). See Table 1B, below, for the list of permit conditions
proposed for incorporation into the SIP.
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\46\ A copy of SIP operating permit No. 082337 is included in
Attachment J1 of Tennessee's June 18, 2025, submission, which is
included in the docket for this NPRM.
\47\ The supplement SIP permit replaces the original permit No.
082237 issued June 11, 2025, and submitted with the June 18, 2025,
redesignation request SIP submission.
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<bullet> Eastman SIP operating permit No. 083740--Issued January
14, 2026, and submitted with Tennessee's January 27, 2026, supplement,
this permit supersedes No. 082237 only for Eastman's HWIs B-248-1 and
248-2's Monitoring Protocol and compliance methodology at Appendix 1 of
permit 083740 (corresponding to Appendix 5 of permit 082237). The
SO<INF>2</INF> emission limits and reporting requirements for B-248-1
and 248-2 at Conditions S5-1 and S6-1, respectively, are unchanged from
permit No. 082237 except to
[[Page 68074]]
reference Appendix 1 for the updated Monitoring Protocol. These
modifications became effective January 14, 2026. See Table 1B, below,
for the list of permit conditions proposed for incorporation into the
SIP.
<bullet> Eastman PSD Construction permit No. 966859F--Issued June
5, 2013, and submitted as part of Tennessee's June 18, 2025,
submission, this permit authorized Eastman to repower the five B-253
coal-fired boilers to natural gas. Condition 6 of this permit states
that on and after the startup date of each modified boiler in the B-253
fuel-burning installation, only natural gas shall be used as fuel.
Tennessee's June 18, 2025, submission requests that the EPA incorporate
Condition 6 into the SIP. See Table 1B, below.
<bullet> Primester title V operating permit No. 574994--Issued
January 1, 2020, and submitted as part of Tennessee's June 18, 2025,
submission, this permit includes the SO<INF>2</INF> emission limit and
compliance requirements for Primester's Vent C--Cellulose Scrap
Recovery Process, B-441-2 at Condition E5-1. The cellulose scrap
recovery process is subject to an SO<INF>2</INF> limit of 1,000 parts
per million, 0.10 percent by volume, dry basis (one hour average), and
0.25 lbs/hr (three-hour average). Tennessee's June 18, 2025, submission
requests that the EPA incorporate Condition E5-1 into the SIP. See
Table 1B, below.
The SO<INF>2</INF> emission limits, other control measures, and
compliance parameters for Eastman's B-83 and B-325 coal-fired boilers
that are already incorporated into the SIP are listed in Table 1A,
below. As mentioned above, the EPA incorporated these conditions from
SIP operating permit No. 080222 and operating permit No. 576501.\48\
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\48\ See 90 FR 57367 (Dec. 11, 2025).
Table 1A--Permanent and Enforceable SO2 Control Measures for Eastman Emission Sources Already Approved in the
Tennessee SIP
----------------------------------------------------------------------------------------------------------------
SO2 emission limit
Eastman emission source or control Permit Condition
measure
----------------------------------------------------------------------------------------------------------------
B-83, Boilers B-18 through B-24 1,248 lb/hr; 30- SIP Operating 1, 3, Attachment A.
and B-325, Boilers B-30 and B- day rolling Permit No. 080222.
31. average.
B-83, Boilers B-23 and B-24.... Operation of Dry SIP Operating 2.
Sorbent Injection Permit No. 080222.
System.
B-325, Boiler B-30............. 317 lb/hr; 30- Operating Permit E3-8, E3-20, Attachment 3.
calendar day No. 576501.
rolling average.
B-325, Boiler B-31............. 293 lb/hr; 30- Operating Permit E3-9, E3-20, Attachment 3.
calendar day No. 576501.
rolling average.
----------------------------------------------------------------------------------------------------------------
Summarized below are brief descriptions of each emission source in
Table 1A. Further discussion for these SO<INF>2</INF> emission limits,
other control measures, and compliance parameters may be found in
section 4.0 of the June 18, 2025, submission.
1. B-325 Powerhouse (Boilers B-30 and B-31) Individual limits:
Eastman's B-325 powerhouse serves two coal-fired boilers--Boilers B-30
and B-31--that vent to a single stack. These boilers have a nominal
heat input capacity of 780 Million British Thermal Units/hour (MMBtu/
hr) (B-30) and 880 MMBtu/hr (B-31) and provide steam for facility
operations. SO<INF>2</INF> emissions from these boilers are controlled
by a spray dryer absorber \49\ (SDA) for each boiler. Boiler B-30 is
equipped with an electrostatic precipitator, and B-31 is equipped with
a fabric filter to capture the dry, solid waste byproduct from the SDA
chemical reaction. The boilers have individual SO<INF>2</INF> emission
limits of 317 lbs/hr (B-30) and 293 lbs/hr (B-31) based on a 30-
calendar day rolling average established in Conditions E3-8 and E3-9 of
title V operating permit No. 576501.\50\
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\49\ SDA is an air pollution control system that uses a mist of
alkaline slurry such as lime sprayed into hot flue gas to remove
acid gases such as SO<INF>2</INF>, hydrochloric acid and
particulates, creating dry, solid byproducts that are then captured
by a baghouse or filter. This semi-dry process cools the gas,
captures pollutants efficiently, and produces easily manageable
solid waste.
\50\ B-325 individual limits were initially authorized in PSD
construction permit No. 955272F, Condition 4 on April 8, 2002, and
incorporated by reference into the title V permit 576501.
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2. B-83 Powerhouse Boilers B-23 and B-24 DSI System: Eastman's B-83
includes coal fired boilers B-23 and B-24, which provide steam and
electricity for the facility and vent to stack C. In 2019, Eastman
installed a portable Dry Sorbent Injection (DSI) system \51\ on Boilers
B-23 and B-24 at the B-83 powerhouse in response to SO<INF>2</INF>
exceedances at monitors in the Sullivan County Area. This control
measure was installed to further reduce SO<INF>2</INF> emissions to
address these monitored violations and ensure attainment of the
standard. This installation occurred after the natural gas repowering
and start-up of the last B-253 boiler--Boiler B-26--on October 4, 2018.
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\51\ DSI is a cost-effective air pollution control technology
that injects powdered alkaline sorbents (like hydrated lime or
Trona) into a flue gas stream to neutralize and remove acid gases
(SO<INF>2</INF>, hydrochloric acid, sulfur trioxide) and heavy
metals (mercury) before they exit smokestacks, using devices like
bag filters or electrostatic precipitators to capture the reacted
pollutants.
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At that time, Eastman selected the portable DSI emission control
because the B-253 boilers were well-controlled, Boilers B-18 through B-
24 at the B-83 powerhouse were uncontrolled for SO<INF>2</INF>, and
because B-23 and B-24 are high pressure baseload boilers that are
operated preferentially over Boilers B-18 through B-22, which are
smaller and operate at a lower pressure. Eastman subsequently installed
and began operation of a permanent DSI system at B-23 and B-24 in
November 2021, designed to reduce SO<INF>2</INF> emissions from the B-
83 boilers as required to maintain and assure compliance with the B-83
and B-325 combined 30-day rolling average 1,248 lb/hr SO<INF>2</INF>
emission limit established at Condition 1 of SIP permit No. 080222. The
permanent DSI system was designed based on a nominal operating
efficiency of 60 percent using sodium bicarbonate as the sorbent.
Operation of the permanent DSI was made enforceable and effective on
March 1, 2023, through SIP operating permit No. 080222, Condition
2.\52\
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\52\ Authorization to operate the DSI system effective March 1,
2023, for B-83, B-23 and B-24 is also established in SIP permit No.
082237, Condition S1-2. See Attachment J1 of Tennessee's on June 18,
2025, submission.
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3. B-83 Powerhouse (Boilers B-18 through B-24) and B-325 Powerhouse
(Boilers B-30 and B-31) Combined SO<INF>2</INF> Emission Limit: TDEC
used air dispersion modeling to establish a 1,248 lb/hr emission limit
for all seven coal-fired boilers at B-83 (B-18 through B-24) and the
two coal-fired boilers at B-325 (B-30 and B-31). The modeled values
were converted to a single 30-day rolling average emission limit
[[Page 68075]]
(combined total for all nine boilers) based on the EPA's longer term
average policy established in the SO<INF>2</INF> Nonattainment Area
Guidance.\53\ For details on how Tennessee established the 30-day,
combined SO<INF>2</INF> emission limit, see section V.C.1.b below and
the EPA's Longer Term Average (LTA) Emission Limits Technical Support
Document (TSD) (LTA TSD).\54\ For reasons discussed in section V.C.1.b,
below, and the EPA's LTA TSD, the EPA proposes to determine that
appropriately set LTA limits provide a reasonable basis by which permit
limits may provide for attainment of the 2010 SO<INF>2</INF> NAAQS. The
combined limit and MRR compliance parameters were authorized in SIP
operating permit No. 080222,\55\ Conditions 1 and 3 and Attachment A.
Condition 1 provides a table of affected Eastman emission sources and
the SO<INF>2</INF> emission limits including the 1,248 lb/hr combined
limit for B-83 and B-325. Condition 3 establishes the compliance
parameters in Attachment A of which were incorporated by reference as
enforceable conditions.\56\
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\53\ See Guidance for 1-Hour SO<INF>2</INF> Nonattainment Area
SIP Submissions; EPA, April 23, 2014, (SO<INF>2</INF> Nonattainment
Area Guidance), which can be found at <a href="https://www.epa.gov/so2-pollution/guidance-1-hour-sulfur-dioxide-so2-nonattainment-area-state-implementation-plans-sip">https://www.epa.gov/so2-pollution/guidance-1-hour-sulfur-dioxide-so2-nonattainment-area-state-implementation-plans-sip</a> (2014) at pp. 22-39 and Appendices B,
C, and D, available in the docket for this action.
\54\ The EPA's LTA TSD is included in the docket for this NPRM.
\55\ SIP operating permit No. 080222 is a federally enforceable
State operating permit issued on March 1, 2023, by TDEC establishing
enforceable SO<INF>2</INF> emission limits and control measures for
Eastman as part of Tennessee's February 23, 2023, nonattainment SIP
for the Sullivan County Area. The permit is included in the docket
for this NPRM.
\56\ The combined SO<INF>2</INF> emission limit for B-83 and B-
325 is established in SIP operating permit No. 082237, which is
included in Tennessee's June 18, 2025, submission.
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The coal-fired boilers at B-83 and B-325 are equipped with
SO<INF>2</INF> Continuous Emission Monitoring Systems (CEMS), but
emissions from the larger boilers (B-23, 24, 30, and 31) are calculated
differently than the older B-83, B-18 through B-22 boilers. Boilers 23,
24, 30, and 31 are subject to the Nitrogen Oxide SIP Call ozone season
program pursuant to 40 CFR part 75 and, therefore, are required to
install and operate in-stack flow monitors. Thus, hourly SO<INF>2</INF>
emissions from these four boilers are calculated based on the
SO<INF>2</INF> CEMS data and flow monitoring.\57\
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\57\ The B-325 individual boilers are equipped with
SO<INF>2</INF> CEMS and flow monitoring system (operated and
maintained in accordance with 40 CFR part 60 appendix B Performance
Specification 6 or 40 CFR part 75 appendix A) with an automated data
acquisition and handling system for measuring and recording
SO<INF>2</INF> concentration (in parts per million), volumetric gas
flow (in standard cubic feet per hour), and SO<INF>2</INF> mass
emissions (in lb/hr) discharged to the atmosphere. Compliance with
the individual limits is determined by calculating hourly
SO<INF>2</INF> emissions from the CEMS data and flow monitoring
established in Condition E3-20, Attachment 3 of the SIP operating
permit.
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Boilers B-18 through B-22, however, are not equipped with flow
monitors, thus SO<INF>2</INF> emissions are calculated in lb/MMBtu
using CEMS data and calculated heat input (from the energy rise of
steam across the boilers) in accordance with 40 CFR 60 appendix A,
Method 19. All 30-day rolling averages must be calculated as specified
in 40 CFR part 63, subpart UUUUU at 63.10021(b), Equation 8) (which is
presented as Equation 4-1 in the June 18, 2025, submission), which
utilizes the hourly emissions rate for a given hour (combined total
emissions for all boilers) and the number of hourly emissions rate
values collected over 30 boiler operating days.\58\ Attachment A of SIP
operating permit No. 080222 requires each CEMS to be fully operational
for at least 95 percent of the operational time of the monitored boiler
during any calendar quarter, and missing data must be addressed by
substituting the higher value of: (1) the last valid hourly emission
rate before, or (2) the first valid hourly emission rate after, the
period of missing data.
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\58\ Boiler operating day means a 24-hour period that begins at
midnight and ends the following midnight during which any fuel is
combusted at any time in any of the boilers. It is not necessary for
the fuel to be combusted the entire 24-hour period.
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For the reasons noted above and as discussed further in the LTA
TSD, the EPA is proposing to find that the 30-day rolling average
combined SO<INF>2</INF> emission limit for the coal-fired boilers at B-
83 (B-18 through B-24) and B-325 (B-30 and B-31) is comparably
stringent to a 1-hour limit and provides for modeled attainment of the
SO<INF>2</INF> standard in the Sullivan County Area. As mentioned
above, the combined 30-day rolling average 1,248 lb/hr SO<INF>2</INF>
emission limit for B-83 and B-325 and the DSI control operations at B-
83, Boilers B-23 and B-24, established in SIP operating permit No.
080222 and the B-325 individual 317 lb/hr and 293 lb/hr SO<INF>2</INF>
limits for Boilers B-30 and B-31, respectively, established at
Conditions E3-8 and E3-9 of title V operating permit No. 576501 were
made permanent through incorporation into the Tennessee SIP on December
11, 2025.\59\
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\59\ See 90 FR 57367 (Dec. 11, 2025).
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The EPA is proposing to incorporate into the SIP the remaining
SO<INF>2</INF> emission limits and other control measures requested for
approval in the State's June 18, 2025, submission that were not made
permanent in the EPA's December 11, 2025, action. Tennessee requests
that the EPA approve into Tennessee's SIP the remaining SO<INF>2</INF>
control measures from SIP operating permit No. 082237, which are
modified in Tennessee's January 27, 2026, SIP operating permit No.
083740 and May 20, 2026, SIP operating permit No. 082237--(Amendment
#1).\60\ These remaining SO<INF>2</INF> control measures apply to the
following Eastman emission sources: B-253 coal-fired units, B-248
hazardous waste incinerators, B-351-5 coal gasification flare, B-334
tail gas incinerator, and B-55-1 organic acids and anhydrides
manufacturing, and Primester B-441 cellulose recovery scrap process.
Table 1B, below, lists the enforceable SO<INF>2</INF> emission limits,
other control measures, and compliance parameters for these remaining
emission sources.\61\
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\60\ Conditions from SIP operating permit No. 083740 and SIP
operating permit No. 082237 (Amendment #1) will be incorporated into
the SIP. These permits contain the most up-to-date version of all of
the requirements included in SIP operating permit 082237.
\61\ See the May 20, 2026, supplement, Attachment C version of
Table 4-4 and Attachment J of Tennessee's June 18, 2025, submission.
Table 1B--Sullivan County Area Enforceable SO2 Control Measures Proposed for Incorporation Into the Tennessee
SIP
----------------------------------------------------------------------------------------------------------------
SO2 emission limit
Emission source or other control Permit Condition(s)
measure
----------------------------------------------------------------------------------------------------------------
Eastman B-253-1; Boilers B-25 Only natural gas PSD Construction 6.
through B-29. shall be used as Permit 966859F.
fuel.
Eastman B-334-1; Incinerator 21.8 lb/hr; 24- SIP Operating * S2-1 and S2-2, Appendix 2.
for Acid Gas Removal and hour block Permit 082237
Sulfur Recovery Plant. average. (Amendment #1 ).
[[Page 68076]]
Eastman B-55-1................. 6.74 lb/hr........ SIP Operating * S4-1 and S4-2.
Permit 082237
(Amendment #1).
Eastman B-248-1; Solid/Liquid 15.2 lb/hr; 30-day SIP Operating * S5-1 and S5-2, Appendix 1.
Chemical Waste Incinerators. average, combined Permit 083740 **.
limit for both
rotary kilns.
Eastman B-248-2; Liquid 2.0 lb/hr; 30-day SIP Operating * S6-1 and S6-2, Appendix 1.
Chemical Waste. average. Permit 083740 **.
Eastman B-351-5; Coal 14.6 lb/hr; 30-day SIP Operating *** S3-1(B), S3-2, S3-3, Appendix 3.
Gasification Cold and Warm rolling average. Permit 082237
Flares. (Amendment #1).
Primester, B-441-2, Vent C..... 1,000 ppm by Title V Operating E5-1.
volume (dry Permit 574994.
basis), 1-hour
average and 0.25
pounds per hour,
3-hour average.
----------------------------------------------------------------------------------------------------------------
* For Eastman SIP operating permits Nos. 082237 (Amendment #1) and 083740, Conditions S2-1, S3-1(B), S4-1, S5-1,
and S6-1 represent the numerical SO2 emission limit/averaging time or control measure and compliance
monitoring; Conditions S2-2, S3-2, S4-2, S5-2, and S6-2 represent the recordkeeping and reporting compliance
requirements. TDEC also requests that general permit conditions G2, G3, and G4 be adopted into the SIP for
both permits Nos. 082237 (Amendment #1) and 083740.
** Permit No. 083740 modifies the parametric monitoring for Eastman B-248-1 and 248-2 HWI and supersedes permit
No. 082237 effective January 14, 2026.
*** Permit No. 082237 (Amendment #1) effective May 13, 2026, corrects the 16.28 lb/hr limit to 14.6 lb/hr and
clarifies the frequency by which SO2 emissions for the B-351 coal gasification flare are automatically
calculated. The permit also updates Condition G4 contingency measures.
A brief description of each emission source in Table 1B is
summarized below. For a more detailed discussion of each SO<INF>2</INF>
emitting unit at Eastman and Primester addressed in Table 1B, please
see section 4.0 of the June 18, 2025, submission including the updated
Table 4-4 submitted with TDEC's May 20, 2026, supplement.
4. B-253 (Boilers B-25 through B-29): From 2014 to 2018, Eastman
converted Boilers B-25 through B-29 from coal-fired boilers to natural
gas-fired boilers. The EPA approved this conversion as an alternative
to best available retrofit technology (BART) for SO<INF>2</INF> for the
B-253 Powerhouse during the first regional haze planning period.\62\
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\62\ TDEC's original April 4, 2008, regional haze SIP identified
the B-253 Powerhouse as a BART-eligible unit. Tennessee subsequently
amended its regional haze SIP (on May 14, 2012, and May 25, 2012) to
establish BART requirements for Eastman including an alternative
BART option to repower (convert coal-fired boilers to natural gas)
Boilers 25-29 by December 31, 2018. Tennessee adopted requirements
on May 9, 2012, to establish BART for B-253, Boilers B-25 through B-
29 during the first regional haze implementation period. See 77 FR
24392 (Apr. 24, 2012) and 77 FR 70689 (Nov. 27, 2012). The BART
alternative became federally enforceable through the issuance of
BART permit No. 066116H (Condition 4(f)) on May 9, 2012, and amended
on May 22, 2012, which changed the conversion completion date to
align with the 1-hour SO<INF>2</INF> NAAQS compliance deadline of
October 4, 2018.
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Condition 6 of PSD permit No. 966859F established a natural gas
fuel restriction for all five B-253-boilers once repowering was
installed and operational.\63\ Compliance with the fuel usage
restriction is based on the design and construction of the boilers,
which include natural gas feed lines and burners that physically
restrict the source's ability to burn other fuels. The start-up date
for the first repowered boiler was April 23, 2014, and the start-up
date for the last repowered boiler was October 4, 2018. Tennessee's
February 9, 2023, and June 18, 2025, submissions request that the EPA
incorporate into the SIP the natural gas fuel usage restriction at
Condition 6 of PSD permit No. 966859F for Boilers B-25 through B-29.
The EPA is proposing to approve this fuel restriction to support
Tennessee's redesignation request showing that attainment of the 2010
SO<INF>2</INF> standard in the Sullivan County Area is due to permanent
and enforceable SO<INF>2</INF> control measures.
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\63\ All five B-253 boilers were converted to natural gas from
2014 to 2018. See Table 4-1 in Tennessee's February 9, 2023,
submission and Table 4-2 in Tennessee's June 18, 2025, submission
for specific natural gas commercial operation for each boiler.
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5. Solid/Liquid Chemical Waste Incinerators (PES B-248-1: Vents D
and E) and Liquid Chemical Waste Incinerator (PES B-248-2: Vent A): The
B-248 incinerator complex consists of three HWIs, one liquid chemical
waste incinerator (B-248-2, Vent A), and two rotary kilns that can burn
solid or liquid chemical waste (B-248-1, Vents D and E). These units
incinerate solid and liquid waste from other processes at Eastman and
are subject to enforceable SO<INF>2</INF> emission limits of 15.2 lb/hr
(B-248-1) and 2.0 lb/hr (B-248-2). SO<INF>2</INF> emissions from these
units are continuously controlled by wet scrubbers (Croll-Reynolds
Clean Air Technologies multi-rod scrubber for each emission point).
These emission limits were first made enforceable through SIP operating
permit No. 080222 submitted with the February 9, 2023, submission. This
permit was superseded by SIP operating permit No. 082237 submitted with
the June 18, 2025, submission, and again superseded by operating permit
No. 083740 submitted with the January 27, 2026, supplement.\64\
Conditions S5-1 and S5-2 establish the 15.2 lb/hr combined
SO<INF>2</INF> limit for the B-248-1 chemical waste incinerators rotary
kilns. Conditions S6-1 and S6-2 establish the 2.0 lb/hr SO<INF>2</INF>
emission limit for B-248-2 liquid chemical waste incinerators.
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\64\ See TDEC's August 25, 2026, email to the EPA Regional
Administrator Kevin McOmber in the docket for this action.
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These two incinerators are not equipped with CEMS. In lieu of CEMS,
compliance with the SO<INF>2</INF> emission limits is based on
continuous calculations of SO<INF>2</INF> emissions using parametric
monitoring of the sulfur feed rate and the pH of the rod scrubber
underflow. Computer simulations using Aspen Plus, a commercially
available software package, were conducted to establish the pH of the
rod scrubber underflow at varying sulfur loading conditions, and the
correlation curve for the highest sulfur feed modeled was used to
develop the relationship between pH and removal efficiency. All removal
efficiencies were determined using the minimum liquid to gas flow rate
ratio (L/G ratio) determined during the most recent Comprehensive
Performance Test (CPT), as required by 40 CFR part 63, subpart EEE, for
each unit.
[[Page 68077]]
Appendix 1 to permit No. 083740 includes the parametric monitoring
requirements for units PES B-248-1 and PES B-248-2. This includes the
continuous monitoring of rod scrubber underflow pH via a pH sensor and
transmitter installed in either the rod scrubber underflow line or the
sump pump. The L/G ratio is calculated from two directly measured
parameters: the stack gas flow rate (which is measured in the ductwork
between the final control device, the wet electrostatic precipitator,
and the induced draft fan located at the stack inlet) and the scrubbing
liquid flow rate (which is measured by liquid flow meters located
between each heat exchanger and the rod scrubber spray). If the L/G
ratio drops below the minimum value set by the most recent CPT, the
SO<INF>2</INF> removal efficiency shall be assumed to be zero for the
purposes of estimating emissions and determining compliance. See
``Description of Monitoring Protocol,'' in Appendix 1 of permit No.
083740 in the January 27, 2026, supplement.
TDEC issued permit No. 083740 on January 14, 2026, to update the
Monitoring Protocol for the hazardous waste incinerators. The
parametric Monitoring Protocol requires Eastman to base the parametric
relationship on the most recently modeled simulations determining the
correlation between the scrubber pH and SO<INF>2</INF> removal
efficiency for the multi-rod scrubbers. If a comprehensive performance
test is conducted in accordance with 40 CFR part 63, subpart EEE after
May 1, 2025, the results of that test may be used to determine the
SO<INF>2</INF> removal rate until a change in the sulfur feed rate
makes the test result unrepresentative of current conditions or until a
subsequent modeled simulation is performed. Additionally, the
Monitoring Protocol requires that when the L/G ratio drops below the
minimum value set by the most recent comprehensive performance test,
then the SO<INF>2</INF> removal efficiency shall be assumed to be zero.
Items 2 and 5 in the Description of Monitoring Protocol section
establish the process for determining the parametric values which are
used to calculate SO<INF>2</INF> emissions. Outlining the applicable
methodology will ensure that the most accurate data is used to
determine SO<INF>2</INF> emissions without delay. If a change to the
method used to set the minimum L/G ratio or pH/SO<INF>2</INF> removal
efficiency correlation curve or to the method used to calculate
SO<INF>2</INF> emissions from the hazardous waste incinerators is
required, TDEC must submit a SIP revision to the EPA for consideration.
Additionally, any changes to the underlying SO<INF>2</INF> emission
rate cannot occur without the EPA approval of a SIP revision. The
Monitoring Protocol does not include operational limits that would be
updated such that it would impact compliance with the modeled
SO<INF>2</INF> limit.
While SO<INF>2</INF> removal efficiencies may be established
through performance testing, SO<INF>2</INF> emissions from the
hazardous waste incinerators are minimal and expected to remain low
because of the sale of Eastman's resin business, and therefore, Eastman
is unlikely to have sulfur feed in sufficient quantity to provide valid
test results.
Tennessee's June 18, 2025, submission requests that the EPA approve
as a permanent and enforceable control measure into the SIP the
SO<INF>2</INF> emission limits for B-248-1 and B-248-2 established in
SIP operating permit No. 082237, Conditions S5-1, S5-2, S6-1 and S6-2,
respectively.\65\ The EPA is proposing to adopt into the Tennessee SIP,
SO<INF>2</INF> emission limits for B-248-1 and B-248-2 as permanent and
enforceable control measures. Additionally, the EPA is proposing to
approve the Monitoring Protocol in Appendix 1 used to calculate
SO<INF>2</INF> emissions and determine compliance with B-248 emission
limits through SIP operating permit No. 083740 submitted as part of
Tennessee's January 27, 2026, supplement.
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\65\ As discussed above, operating permit No. 083740 supersedes
operating permit No. 082237 for the HWIs.
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6. Coal Gasification Cold and Warm Flares (B-351-5): These flares
are subject to a combined 14.6 lb/hr, 30-day rolling average
SO<INF>2</INF> emission limit. Tennessee used air dispersion modeling
to establish this emission limit based on the EPA's LTA policy in the
SO<INF>2</INF> Nonattainment Area Guidance. For details on how
Tennessee established the 30-day, combined SO<INF>2</INF> emission
limit, see section V.C.1.b below and the EPA's LTA TSD. Initially, TDEC
established a 16.28 lb/hr emission limit in SIP operating permit No.
080222, included with the February 9, 2023, submission. The updated
emission limit is enforceable through SIP operating permit No. 082237
(Amendment #1) \66\ as issued on May 13, 2026.\67\
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\66\ The B-351 emission limit included in SIP operating permit
No. 0822337 is incorrect. Tennessee corrected the permit limit from
16.28 lb/hr to 14.6 lb/hr in its May 20, 2026, supplement.
\67\ Tennessee's May 20, 2026, supplement notes that the
inclusion of the 16.28 lb/hr limit in the final permit for 082237
was an error, leading to the need to issue 082237 (Amendment #1).
Tennessee clarifies in its August 20, 2026, letter to the EPA
Regional Administrator Kevin McOmber that with the submission of the
May 20, 2026, supplement, the State is not asking for the EPA to
take action on the 16.28 lb/hr limit, and that it is included in
permit 082237 (Amendment #1) for informational purposes only. Both
emission limits apply to the flare, and only the 14.6 lb/hr limit is
requested for incorporation into the SIP.
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The cold and warm flares are each equipped with three High Energy
Ignition/High Btu flare pilots. These flares have ``flame on'' and
temperature indicators to ensure reliable combustion. In lieu of CEMS,
compliance with the SO<INF>2</INF> emission limit is based on
parametric monitoring of the control valve position and control valve
upstream pressure. Eastman is required to continuously track the
control valve opening position and upstream pressure each hour (at
least once every 15 minutes). These parameters are used to calculate
the volumetric flow rate of the gas stream routed to the flares. The
known plant gas stream composition is also used to calculate the sulfur
content of the gas stream routed to the flares (assuming a total
conversion of sulfur to SO<INF>2</INF> when calculating emissions).
Tennessee's June 18, 2025, submission requests the EPA incorporate into
the SIP as a permanent and enforceable control measure the enforceable
SO<INF>2</INF> emission limit for B-351-5 established in the May 13,
2026, version of SIP operating permit No. 082237 (Amendment #1),
Condition S3-1(B) along with compliance method (A) (including Appendix
3 which contains the Monitoring Protocol), and the recordkeeping and
reporting requirements at Condition S3-2.
7. Incinerator for Acid Gas Removal and Sulfur Recovery Plant (or
Tail Gas B-334-1): Eastman's tail gas incinerator oxidizes residual
sulfur compounds such as hydrogen sulfide (H<INF>2</INF>S) left over
from the combustion of the gas stream. The emission unit is subject to
an SO<INF>2</INF> emission limit of 21.8 lb/hr (24-hour block average),
first made enforceable through SIP operating permit No. 080222
submitted with the February 9, 2023, submission and subsequently
included in SIP operating permit No. 082237 (Amendment #1) at Condition
S2-1 and the Monitoring Protocol and periodic reporting requirements at
Appendix 2 and Condition S2-2, submitted in the June 25, 2025,
submission, as amended in the May 20, 2026, supplement. The tail gas
incinerator is equipped with a direct flame afterburner. Compliance
with the SO<INF>2</INF> emission limit is based on continuous (at least
once every 15 minutes) parametric monitoring of the H<INF>2</INF>S and
gas flow rate of the tail gas to calculate the emission rate in lb/hr
for a 24-hour block average. The EPA is proposing to incorporate into
the SIP as a permanent and enforceable control measure the
SO<INF>2</INF> emission limit for B-
[[Page 68078]]
334-1 established in SIP operating permit No. 082237 (Amendment #1) at
Condition S2-1, the periodic reporting requirements at Condition S2-2,
and the Monitoring Protocol at Appendix 2.
8. B-55-1, Organic Acids & Anhydrides Manufacturing, Vents B, C, E,
I, and K: Tennessee has established a 6.74 lb/hr SO<INF>2</INF>
emission limit for B-55-1 effective March 8, 2026, at Condition S4-1 of
SIP operating permit No. 082237 (Amendment #1), with associated
reporting requirements at Condition S4-2. To assess the need for
temporary SO<INF>2</INF> emission controls on the batch reactors and/or
sludge handling belt to meet this limit under maximum operating
conditions, Eastman was required to conduct an initial performance test
to determine the amount of SO<INF>2</INF> emitted from this source no
later than June 6, 2026, in accordance with the methods and procedures
specified in 40 CFR part 60 appendix A. As Vent E was not in service at
the issuance date of Permit 082237 or 082237 (Amendment #1), condition
S4-1 requires an initial performance test be conducted no later than
180 days following any restart of the associated process.
On October 10, 2025, TDEC accepted the test reports for B-55-1 Vent
K, with testing done June 02, 2025, and B-55-1 Vents C and I, with
testing done May 08 through June 09, 2025. On April 1, 2026, TDEC
accepted the test report for B-55-1 Vent B summarizing testing
completed February 20 through 23, 2026. The EPA is proposing to
incorporate into the SIP as a permanent and enforceable control measure
the SO<INF>2</INF> emission limit for B-55-1 established in SIP
operating permit No. 082237 (Amendment #1) Conditions S4-1 and the
periodic reporting requirements at Condition S4-2.
9. Primester (B-441-2: Vent C)--Cellulose Scrap Recovery Process:
This source rejects dope from various points in the acetylation
operation to recover cellulose sludge for reuse at the plant. Emissions
are controlled by a scrubber using a water solution with caustic added.
The cellulose scrap recovery process is subject to SO<INF>2</INF>
limits of 1,000 parts per million, 0.10 percent by volume, dry basis
(one hour average) and 0.25 lbs/hr (three-hour average).
In lieu of CEMS, compliance with the SO<INF>2</INF> emission limits
is based on parametric monitoring of the scrubber flow rate and
scrubber underflow pH. Per Condition E5-1 of title V permit No. 574994,
the scrubber flow rate and pH shall be continuously monitored and
recorded. Primester is required to maintain a minimum scrubber flow
rate and a minimum scrubber pH, for which both minimum parametric
values are included in the compliance method of condition E5-1 of title
V permit No. 574994, to assure compliance with the SO<INF>2</INF>
limits. Any updates to these minimum parametric values would require
the EPA approval of a SIP revision. The EPA is proposing to incorporate
into the SIP Condition E5-1 of title V operating permit No. 574994 as a
permanent and enforceable measure.
B. Nonattainment Planning Requirements
1. Clean Air Act Requirements
Subpart 1 of part D, comprised of CAA sections 171-179B, sets forth
the basic nonattainment requirements applicable to all nonattainment
areas. CAA Section 172(c) sets forth the basic requirements of
attainment plans for nonattainment areas that are required to submit
them pursuant to CAA section 172(b). All areas that were designated
nonattainment for the 2010 1-hour SO<INF>2</INF> NAAQS were designated
under CAA subpart 1 in accordance with the deadlines in subpart 5. A
thorough discussion of the requirements contained in CAA section 172(c)
can be found in the General Preamble for Implementation of Title I.\68\
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\68\ See CAA section 107(d)(3)(E)(iv).
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CAA section 172 requires States with nonattainment areas to submit
plans providing for timely attainment and meeting a variety of other
requirements. Tennessee has satisfied the part D obligation to submit
attainment planning requirements for the Sullivan County Area through
the State's May 12, 2017, and February 9, 2023, nonattainment SIP
submissions and resubmission of RACM/RACT in the June 18, 2025,
redesignation request and maintenance plan submission. See section II
of this NPRM. The February 9, 2023, nonattainment SIP included a
modeled demonstration of attainment for the 2010 SO<INF>2</INF> NAAQS
by the April 5, 2027, attainment date. The EPA addresses how Tennessee
satisfied each CAA section 172(c) element below.
CAA Sections 172(a)(2), 192(a), and 179(d)--Attainment Dates for
Nonattainment Areas: For a nonattainment area, CAA section 172(a)(2)
establishes that the attainment date shall be the date by which
attainment can be achieved as expeditiously as practicable, but no
later than five years from the date the area was designated
nonattainment, unless the Administrator determines an extension of up
to 10 years is appropriate. CAA section 192(a) requires that SIPs for
nonattainment areas must provide for attainment of the relevant NAAQS
as expeditiously as practicable, but no later than five years from the
effective date of the nonattainment designation. The effective date of
the designation of the Sullivan County Area to nonattainment was
October 4, 2013,\69\ and five years from that date was October 4, 2018.
As detailed in section II of this NPRM, Tennessee initially submitted
its first nonattainment SIP on October 12, 2017, which included a
modeled attainment demonstration. Subsequently, on April 5, 2022, the
EPA published a FFA determining that the State failed to attain by the
applicable attainment date, triggering a requirement under CAA section
179(d) for Tennessee to submit to the EPA a revised nonattainment SIP
for the Sullivan County Area within one year of the publication of the
FFA Federal Register (i.e., April 5, 2023), which provides for
attainment of the 2010 SO<INF>2</INF> standard as expeditiously as
practicable, but no later than five years from the FFA's Federal
Register publication date (i.e., April 5, 2027).
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\69\ See 78 FR 47191 (Aug. 5, 2013).
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The EPA previously determined that the State did not meet its
obligation to provide for attainment within five years of the
nonattainment designation. The EPA proposes to find that TDEC met its
obligation to provide its revised nonattainment planning SIP through
the February 9, 2023, second nonattainment SIP and that the State
appropriately developed its modeled attainment demonstration, as
discussed in section V.C.1.b. The EPA is also proposing that the
nonattainment SIP ensured attainment of the 2010 SO<INF>2</INF> NAAQS
as expeditiously as practicable and earlier than the April 5, 2027,
date as evidenced by TDEC submitting its redesignation request and
maintenance plan by June 18, 2025, with the same modeling demonstration
used for attainment supporting its maintenance demonstration. In
section V.C.1.a of this NPRM, the EPA also examines the actual
monitored SO<INF>2</INF> concentrations in Table 2, below, and notes
that with 2020-2022 design values, all monitors in the Area were in
attainment and have remained in attainment through 2023-2025. Moreover,
Table 3, below, shows that the annual 99th percentile daily maximum 1-
hour SO<INF>2</INF> concentration has remained below the standard at
all four monitors since 2022. If there are no air quality monitors
located in the affected area, or there are air quality monitors located
in the area but analyses show that none of the monitors are in the area
of maximum concentration, then air
[[Page 68079]]
quality dispersion modeling will generally be needed to estimate
SO<INF>2</INF> concentrations in the area. The monitoring information,
taken together with the air quality modeling, ensures that the area
attained by the submission of the State's June 18, 2025, redesignation
request and maintenance plan, slightly more than two years after
publication of the FFA and over 21 months ahead of the CAA section
179(d) attainment date.
CAA Sections 172(b), 191(a), and 179(d)--Schedule for Plan
Submission: Under CAA section 172(b) and consistent with CAA section
191(a), the Administrator required Tennessee to submit a SIP revision
for the Sullivan County Nonattainment Area within 18 months of the
October 4, 2013, effective date of the nonattainment redesignation. As
noted in section II of this NPRM, on March 18, 2016, the EPA published
a FFS pursuant to CAA section 110(k)(1)(B), finding that Tennessee had
failed to submit the SO<INF>2</INF> nonattainment SIP by the submission
deadline of April 4, 2015.\70\ TDEC submitted its first nonattainment
plan on May 12, 2017. Subsequently, with the publication of the FFA on
April 5, 2022, the Administrator required Tennessee to submit a SIP
revision within one year of the publication (i.e., April 5, 2023),
pursuant to CAA section 179(d). The EPA proposes to find that TDEC met
this requirement by submitting its SIP revision on February 9, 2023,
which was sooner than one year from when the FFA published.
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\70\ See 81 FR 14736.
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CAA Section 172(c)(1)--Subpart 1 RACM/RACT Requirements: Subpart 1
requires that each attainment plan ``provide for the implementation of
all reasonably available control measures as expeditiously as
practicable (including such reductions in emissions from the existing
sources in the area as may be obtained through the adoption, at a
minimum, of reasonably available control technology) and shall provide
for attainment of the national primary ambient air quality standards.''
\71\ The EPA has consistently interpreted this provision to require
only implementation of potential RACM that could advance
attainment.\72\ Thus, when an area is already attaining the standard,
no additional RACM measures are required. The EPA's interpretation that
Subpart 1 requires only the implementation of RACM measures that would
advance attainment was upheld by the United States Court of Appeals for
the Fifth Circuit \73\ and by the United States Court of Appeals for
the D.C. Circuit.\74\ In its June 18, 2025, submission, Tennessee
determined that no additional control measures are necessary in the
Sullivan County Area to satisfy the CAA section 172(c)(1) RACM
requirement beyond those measures that provide for attainment of the 1-
hour SO<INF>2</INF> NAAQS.
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\71\ See CAA section 172(c)(1).
\72\ See NRDC v. EPA, 571 F.3d 1245 (D.C. Cir. 2009); Sierra
Club v. EPA, 294 F.3d 155 (D.C. Cir. 2002).
\73\ Sierra Club v. EPA, 314 F.3d 735, 743-745 (5th Cir. 2002).
\74\ Sierra Club v. EPA, 294 F.3d 155, 162-163 (D.C. Cir. 2002);
NRDC v. EPA, 571 F.3d 1245, 1252 (D.C. Cir. 2009).
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The EPA is proposing to determine that Tennessee's Subpart 1 RACM
determination is approvable on the basis that no additional reasonably
available controls would have advanced the April 5, 2027, statutory
attainment date. Tennessee's plan for attaining the 1-hour
SO<INF>2</INF> NAAQS in the Sullivan County Area is based on several
measures, as mentioned above, including repowering the B-253 boilers
from coal to natural gas operation, which was completed October 4,
2018, as an alternative to SO<INF>2</INF> BART for Eastman. The BART
alternative became federally enforceable with the issuance of BART
permit 066116H on May 9, 2012. Condition 4(f) of permit 066116H
requires the repowering of B-253 to be completed no later than the
compliance deadline for the 1-hour SO<INF>2</INF> NAAQS.
As discussed above, the EPA is proposing to incorporate into the
SIP Condition 6 of PSD construction permit 966859F, which states that
on and after the startup date of each modified boiler in the B-253
fuel-burning installation, only natural gas shall be used as fuel.
Also, Tennessee evaluated B-325 Boiler 31 and determined that the SDA/
fabric filter baghouse combination already in place constitutes RACT,
and therefore, that no further analysis is required. Tennessee
considered a range of measures to reduce SO<INF>2</INF> emissions for
the remaining B-83 and B-325 boilers including switching to low-sulfur
coal, upgrading or adding new control equipment, converting existing
coal-fired boilers to natural gas, and replacing existing coal-fired
boilers with natural gas boilers. Tennessee determined that these other
measures are not reasonable for a variety reasons, including
infeasibility and cost, and that they were not needed to attain the
NAAQS and would not advance the attainment date.\75\ In addition,
Tennessee evaluated other operations at Eastman as well as additional
sources within and adjacent to the Area and determined that no
additional controls were required as RACT.
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\75\ See Section 5 of Tennessee's February 9, 2023, submission
and Section 4 of Tennessee's submission for additional details on
the measures analyzed.
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Tennessee has determined that existing emission limits also
constitute RACT, and the EPA proposes to concur with the State's RACT
analysis, initially submitted in the February 9, 2023, submission and
subsequently included in the June 18, 2025, submission. Based on air
dispersion modeling of the repowering of Eastman's powerhouse,\76\ the
installation of add-on controls for Eastman's B-83 boilers B-23 and B-
24, the adoption of a combined emission limit for Eastman's B-83 and B-
325 powerhouses, and the adoption of existing emission limits into the
SIP for other SO<INF>2</INF> emitting sources at Eastman and Primester,
Tennessee determined that no additional measures are necessary for
attainment and no potential measures which, if considered collectively,
would advance the April 5, 2027, attainment year by one year or
more.\77\ The EPA notes that the Area first started monitoring
attainment of the 2010 SO<INF>2</INF> NAAQS with a 2018-2020 design
value and continues to attain the standard. Therefore, the EPA proposes
to approve Tennessee's determination that the State has satisfied its
RACM obligations under CAA section 172(c)(1).
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\76\ See section V.C.1.b of this NPRM for discussion of the air
dispersion modeling.
\77\ Reviewing courts have upheld EPA's interpretation of RACM
as encompassing only those measures necessary to advance attainment.
See Sierra Club v. EPA, 314 F.3d 735, 743-745 (5th Cir. 2002);
Sierra Club v. EPA, 294 F.3d 155, 162-163 (D.C. Cir. 2002); NRDC v.
EPA, 571 F.3d 1245, 1252 (D.C. Cir. 2009).
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CAA Section 172(c)(2)--RFP: CAA section 172(c)(2) states that
nonattainment plans must require RFP. RFP is defined in CAA section
171(1) as ``such annual incremental reductions in emissions of the
relevant air pollutant as are required by part D or may reasonably be
required by EPA for the purpose of ensuring attainment of the
applicable NAAQS by the applicable attainment date.''
In the SO<INF>2</INF> Nonattainment Area Guidance, the EPA notes
that the definition at CAA section 171(1) is ``most appropriate for
pollutants that are emitted by numerous and diverse sources, where the
relationship between any individual source and the overall air quality
is not explicitly quantified, and where the emission reductions
necessary to attain the NAAQS are inventory-wide.'' \78\ The Guidance
[[Page 68080]]
explains that ``the definition is generally less pertinent to
pollutants like SO<INF>2</INF> that usually have a limited number of
sources affecting areas of air quality which are relatively well
defined, and emissions control measures for such sources result in
swift and dramatic improvement in air quality.'' \79\ As a result, the
Guidance goes on to note that in the 1992 General Preamble, the EPA
explained that RFP for SO<INF>2</INF> is best construed as ``adherence
to an ambitious compliance schedule.'' \80\
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\78\ See SO<INF>2</INF> Nonattainment Area Guidance at p. 40.
The document is available in the docket for this action.
\79\ Id. at 40.
\80\ See 57 FR 13498, 13547 (Apr. 16, 1992).
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While the EPA expects that RFP for SO<INF>2</INF> nonattainment
areas should yield significant emission reductions under an ambitious
compliance schedule, the Sullivan County Area has already achieved
significant permanent and enforceable reductions in SO<INF>2</INF>
emissions, such as the reduction of SO<INF>2</INF> emissions from 2011
to 2022 from coal-fired boilers at Eastman from 21,859 tons to 3,334
tons.\81\ These reductions have led to sustained monitored ambient
SO<INF>2</INF> concentrations below the 2010 1-hour SO<INF>2</INF>
NAAQS substantially earlier than the applicable attainment date, as
demonstrated in Table 2. As stated above, TDEC determined, and the EPA
agrees, that no RACM exists that would advance the attainment date for
the Area. With the emission reductions already achieved resulting in
sustained ambient SO<INF>2</INF> concentrations below the 2010 1-hour
SO<INF>2</INF> NAAQS, the EPA is proposing to find that RFP has already
been made and that Tennessee's second nonattainment SIP has met the RFP
provisions of CAA section 172(c)(2).
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\81\ See Table 5 in this NPRM.
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CAA Section 172(c)(3)--Emissions Inventory: CAA section 172(c)(3)
requires nonattainment plans to include a comprehensive, accurate, and
current inventory of actual emissions from all sources of the relevant
pollutant or pollutants in the nonattainment area. As noted in section
II of this NPRM, the EPA approved Tennessee's 2011 base year emission
inventory for the Sullivan County Area March 1, 2021,\82\ as satisfying
the requirements of CAA section 172(c)(3).\83\
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\82\ Id.
\83\ Tennessee also included a base year inventory of 2017 to
support its February 9, 2023, second nonattainment SIP.
---------------------------------------------------------------------------
CAA Section 172(c)(4) and 172(c)(5)--Identification and
Quantification of Emissions and Nonattainment New Source Review
Permits: CAA section 172(c)(4) requires the identification and
quantification of allowable emissions for major new and modified
stationary sources to be allowed in an area, and CAA section 172(c)(5)
requires source permits for the construction and operation of new and
modified major stationary sources anywhere in the nonattainment area.
Tennessee currently has a SIP-approved part D NNSR permitting program
in place in Chapter 1200-03-09 of the Tennessee Air Pollution Control
Regulations (TAPCR). As mentioned above, on March 1, 2021, the EPA
determined that Tennessee's SIP-approved NNSR program satisfies the
requirements of section 172(c)(5) of the CAA for the Sullivan County
Area.\84\
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\84\ See 86 FR 11873 (Mar. 1, 2021).
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Furthermore, Tennessee's air quality modeling, submitted initially
in the February 9, 2023, second nonattainment plan and resubmitted in
the June 18, 2025, submittal, accounts for known expected growth within
the Area that consists of the construction and startup of three new
natural gas boilers (0.64 tons per year, each) and a methanolysis plant
(0.43 tons per year), each of which is modeled at their potential to
emit (PTE). Tennessee has met CAA section 172(c)(4) and 172(c)(5)
requirements. The EPA is further proposing that the use of the future
PTE for the natural gas boilers and the methanolysis plant's natural
gas-fired furnace in the modeling also meets CAA section 172(c)(4).
CAA Section 172(c)(6)--Other Measures: CAA section 172(c)(6)
requires each nonattainment plan to include enforceable emission
limitations and other control measures, means, or techniques, as well
as schedules and timetables for compliance as necessary to provide for
attainment by the applicable attainment date. The requirements under
CAA section 172(c)(6) for nonattainment plans are similar to those
under CAA section 110(a)(2)(A) for infrastructure SIPs, which the EPA
previously approved for Tennessee.\85\ However, in the EPA's action
approving Tennessee's infrastructure SIP as satisfying CAA section
110(a)(2)(A) for the 2010 1-hour SO<INF>2</INF> NAAQS, the EPA
explained that for nonattainment plans, ``Emissions limitations and
other control measures, whether on coal-fired EGUs or other
SO<INF>2</INF> sources, that may be needed to attain and maintain the
NAAQS in areas designated nonattainment for that NAAQS are due on a
different schedule from the section 110 infrastructure SIP submission.
A state, like Tennessee, may reference pre-existing SIP emission limits
or other rules contained in part D plans for previous NAAQS in an
infrastructure SIP submission for purposes of section 110(a)(2)(A).''
\86\ In its February 9, 2023, second nonattainment plan, TDEC notes
that compliance dates for control measures in the attainment
demonstration must be as expeditious as practicable, and attainment
plans should require sources to comply with the requirements of the
attainment strategy at least one calendar year before the attainment
date. SIPs should be able to provide at least one calendar year of air
quality monitoring data before the attainment deadline to demonstrate
that the plan is providing for attainment. To account for its control
measures that were put in place expeditiously, Tennessee provided the
permits for selected controls that were determined necessary to bring
the area into attainment. Tennessee, in its February 9, 2023, second
nonattainment plan, determined that there were no additional control
measures that would advance the attainment date. Additionally, as
discussed below, Tennessee's February 9, 2023, submission contains
contingency measures that would be enacted within specified timeframes
in the event ambient air monitoring exceeds SO<INF>2</INF> levels to
ensure attainment of the 2010 1-hour SO<INF>2</INF> NAAQS by the
applicable attainment date. Furthermore, Tennessee has demonstrated in
its redesignation request and maintenance plan that the Area has
attained well in advance of the 2027 attainment date. Therefore, the
EPA is proposing to find that Tennessee's February 9, 2023, SIP
submittal has met the requirements of 172(c)(6).
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\85\ See 81 FR 85410 (Nov. 28, 2016).
\86\ See id. at 85415.
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CAA Section 172(c)(9)--Contingency Measures: CAA section 172(c)(9)
requires that nonattainment plans contain contingency measures that
take effect without further action by the State or the EPA if the
nonattainment area fails to meet RFP or attain the NAAQS by the
applicable attainment date. Although CAA section 172(c)(9) requires
plans to contain contingency measures that take effect if a
nonattainment area fails to make RFP, the EPA notes that the Sullivan
County Area has already demonstrated RFP with the emission reductions
achieved at Eastman, which are submitted for the SIP to be permanent
and enforceable, including fuel conversion of B-253 boilers 25-29, the
installation of the permanent DSI controls on B-83 for boilers 23 and
24, the adoption of a combined emission limit for boiler houses B-83
and B-325, individual emission limits for boilers 30 and 31, and
updates to emission limits for HWIs, flares, and the sulfur recovery
[[Page 68081]]
plant incinerator, and the emission limits included for the nearby
source of Primester. These required controls are proposed for
incorporation into the SIP via conditions in SIP operating permit No.
080222 (superseded in part by SIP operating permit No. 082237
(Amendment #1)) and SIP operating permit No. 083740, PSD permit No.
955272F for Eastman, and title V operating permit No. 574994 for
Primester. As described above, the EPA is proposing to find that RFP
has already been made and that Tennessee's February 9, 2023, SIP
submission has therefore met CAA section 172(c)(2).
Furthermore, although CAA section 172(c)(9) requires plans to
contain contingency measures that take effect if a nonattainment area
fails to meet the NAAQS, the EPA notes that the Sullivan County Area
has already demonstrated attainment with the permanent and enforceable
emission reductions achieved at Eastman and emission limits included
for the nearby source of Primester. As to the contingency measures
required to take effect under CAA section 172(c)(9) if a nonattainment
area fails to attain the NAAQS by the applicable attainment date,
Tennessee's February 9, 2023 SIP submission contains contingency
measures consistent with the 2014 SO<INF>2</INF> Guidance for 1-hour
SO<INF>2</INF> Nonattainment Area SIP Submissions.\87\ These
contingency measures would be triggered upon notification by Tennessee
that either: (1) a reference monitor for the area has registered four
validated daily maximum one-hour ambient SO<INF>2</INF> concentrations
in excess of the standard during calendar years 2024, 2025, 2026, or
2027; or (2) that a monitored SO<INF>2</INF> violation based on the
design value occurred during or after calendar year 2028.
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\87\ The SO<INF>2</INF> Nonattainment Area Guidance explains
that ``Since SO<INF>2</INF> control measures are by definition based
on what is directly and quantifiably necessary to attain the
SO<INF>2</INF> NAAQS, it would be unlikely for an area to implement
the necessary emission controls yet fail to attain the NAAQS.
Therefore, for SO<INF>2</INF> programs, the EPA has explained that
`contingency measures' can mean that the air agency has a
comprehensive program to identify sources of violations of the
SO<INF>2</INF> NAAQS and to undertake an `aggressive' follow-up for
compliance and enforcement . . . .''
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Upon activation of a trigger, Tennessee will notify Eastman that a
reference monitor has registered four validated daily maximum 1-hour
ambient SO<INF>2</INF> concentrations in excess of the standard during
a calendar year. Eastman would then be required, without any further
action from Tennessee or the EPA, to undertake a full system audit of
all SO<INF>2</INF>-emitting emissions units. Then, within 30 days of
the notification, Eastman must submit a written system audit report to
Tennessee. The system audit report must include certain information
identified in the submittal, including, but not limited to, recommended
provisional SO<INF>2</INF> emission control strategies for each
affected unit and evidence that these control strategies have been
deployed, as appropriate. Once Tennessee receives the system audit
report, it will immediately begin a 30-day evaluation period to
diagnose the cause of the monitored exceedance, followed by another 30-
day period during which Tennessee will consult with Eastman to develop
and implement operational changes as necessary to prevent future
violations of the standard. Examples of changes may include fuel
switching to reduce or eliminate the use of sulfur-containing fuels or
physical or operational reduction of production capacity. Finally, if a
permit modification is deemed necessary by TDEC, Tennessee would issue
a final permit within the State's statutory timeframes required by
TAPCR 1200-03-09. Any new emission limit required by such a permit
would be submitted to the EPA as a SIP revision. If an emission source
is found to be noncompliant with a SIP emission limit, the Technical
Secretary of Tennessee will determine if additional limits are
necessary to meet the requirements of CAA section 172(c)(9).
The EPA is proposing to find that Tennessee's contingency measures
in the February 9, 2023, SIP revision satisfy the applicable
requirements of CAA section 172(c)(9) because the contingency measures
outlined above constitute a comprehensive program to identify sources
of violations of the SO<INF>2</INF> NAAQS that includes requirements of
follow-up for compliance and enforcement, and therefore, the State will
be able to address a failure to make RFP or to attain the NAAQS.
2. Attainment Demonstration
To demonstrate future attainment of the NAAQS by predicting the
effect of air emissions on ambient air quality, States may be required,
under CAA section 110(a)(2)(K), to include air quality modeling and the
associated data in a SIP submittal.
To demonstrate that Tennessee's control strategy will provide for
timely attainment of the 2010 1-hour SO<INF>2</INF> NAAQS as
expeditiously as practicable, but no later than the April 5, 2027,
attainment date, TDEC's attainment demonstration included a modeling
analysis, which followed the procedures in the EPA's Guideline on Air
Quality Models in 40 CFR part 51, Appendix W. TDEC included an
atmospheric dispersion modeling analysis using AERMOD that accounted
for all source-specific SIP revisions for units at Eastman and
Primester, as well as modeled PTE of any smaller units at Eastman and
nearby sources not within the nonattainment area that were not included
as source-specific SIP revisions. As discussed in more detail in
section V.C.1.b of this NPRM and the Sullivan County SO<INF>2</INF>
Modeling TSD, the model predicted a maximum three-year average 99th
percentile of daily maximum 1-hour average SO<INF>2</INF> concentration
for the Sullivan County Nonattainment Area of 74.82 ppb, a value below
75 ppb, that demonstrates the 2010 SO<INF>2</INF> NAAQS will be
attained by April 5, 2027. Based on results of the modeling and TDEC's
approach, the EPA proposes to find that Tennessee's attainment
demonstration satisfies the requirements under CAA section 110(a)(2)(K)
by performing appropriate air quality modeling and providing the
associated data.
3. The EPA's Proposed Approval of Tennessee's 2023 Sullivan County
SO<INF>2</INF> Nonattainment SIP
Based on the EPA's review and evaluation of the information in
sections V.A, V.B, and V.C of this NPRM, the EPA is proposing to find
that Tennessee's February 9, 2023, second nonattainment SIP for the
2010 SO<INF>2</INF> NAAQS satisfies the applicable requirements of CAA
sections 110(a)(2)(D)(i)(I), 110(a)(2)(I), 110(a)(2)(K), and 110(l). As
discussed above in section II, the EPA issued an FFA since the Sullivan
County Area did not attain the relevant NAAQS within five years of the
October 4, 2013, nonattainment designation. Once the CAA sections 191
and 192 deadlines were missed, this triggered a new CAA section 179(d)
deadline to submit a nonattainment SIP by April 5, 2023, in lieu of the
CAA section 191 and 192 requirements, and established an attainment
date of April 5, 2027. The EPA has determined that Tennessee has
satisfied the CAA requirements, and thus, has fully addressed the
nonattainment plan provisions for the Sullivan County Nonattainment
Area.
C. Redesignation Criteria
The five redesignation criteria under CAA section 107(d)(3)(E),
identified in section III, above, are discussed in greater detail for
the Sullivan County Area in the following paragraphs.
[[Page 68082]]
1. Criterion (1)--The Sullivan County Area Has Attained the
SO<INF>2</INF> NAAQS
For redesignating a nonattainment area to attainment, the CAA
requires the EPA to determine that the area has attained the applicable
NAAQS.\88\ There are generally two components needed to support an
attainment determination for the 2010 SO<INF>2</INF> NAAQS, which
should be considered interdependently. The first component relies on
air quality monitoring data. For SO<INF>2</INF>, any available
monitoring data would need to indicate that all monitors in the
affected area are meeting the standard as stated in 40 CFR 50.17 using
data analysis procedures specified in 40 CFR part 50, Appendix T. The
second component relies on air quality modeling data. If there are no
air quality monitors located in the affected area, or there are air
quality monitors located in the area but analyses show that none of the
monitors are in the area of maximum concentration, then air quality
dispersion modeling will generally be needed to estimate SO<INF>2</INF>
concentrations in the area. Such dispersion modeling should be
conducted to estimate SO<INF>2</INF> concentrations throughout the
nonattainment area using actual emissions and meteorological
information for the most recent three calendar years.\89\
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\88\ See CAA section 107(d)(3)(E)(i).
\89\ In its June 18, 2025, submission, Tennessee provides an
analysis of the existing monitoring network and states that
Tennessee believes that the Andrew Johnson site (AQS ID: 47-163-
6003) is most representative of the maximum impact in the Area
(Section 2.2 of the June 18, 2025, submission). However, the State
does not rely on only air quality monitoring to show that the Area
has attained. Instead, TDEC provides an air quality modeling
analysis--with modeled potential to emit (PTE) in lieu of actual
emissions--to both confirm that the Area has attained and to show
that the Area will continue to maintain the NAAQS.
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However, the EPA may also make determinations of attainment based
on the modeling for the affected area, eliminating the need for
separate actuals-based modeling to support a redesignation request.
Furthermore, the EPA's SO<INF>2</INF> Nonattainment Area Guidance
states that ``An approvable attainment demonstration would be an air
quality modeling analysis that demonstrates that the emission limits in
the plan will suffice to provide for timely attainment of the affected
standard. In cases where the necessary emission limits have not
previously been made a part of the SIP, or have not otherwise become
federally enforceable, the plan needs to include the necessary
enforceable limits in adopted form suitable for incorporation into the
SIP in order for it to be approved by the EPA.'' \90\ Thus, a
demonstration that the control strategy in the SIP has been fully
implemented (compliance records demonstrating that the control measures
have been implemented as required by the approved SIP) would also be
relevant for making the determination. As noted above, TDEC provides
emissions data to demonstrate compliance with the SO<INF>2</INF> permit
limits in its final SIP submission.
---------------------------------------------------------------------------
\90\ See SO<INF>2</INF> Nonattainment Area Guidance at p. 9,
available in the docket for this action.
---------------------------------------------------------------------------
a. Monitoring Data
A SO<INF>2</INF> monitoring site is considered as attaining the
2010 1-hour SO<INF>2</INF> NAAQS if it meets the NAAQS as determined in
accordance with 40 CFR 50.17 and appendix T of part 50, based on three
complete, consecutive calendar years of quality-assured air quality
monitoring data. Specifically, to attain the SO<INF>2</INF> NAAQS at
each monitoring site, the 3-year average of the annual 99th percentile
(fourth highest value) of daily maximum 1-hour average concentrations
measured at each monitor within an area must be less than or equal to
75 ppb. The data must be collected and quality-assured in accordance
with 40 CFR part 58 and recorded in the EPA Air Quality System (AQS).
The monitors should have remained at the same location for the duration
of the monitoring period required for demonstrating attainment.
Tennessee currently operates four ambient SO<INF>2</INF> monitors
in the Area, as shown in Tables 2 and 3, below. As shown in Table 2,
the design values at the Ross N. Robinson and Skyland Dr. monitors have
generally decreased since 2019, and the design values at the Andrew
Johnson School and Happy Hill monitors, which began operation later,
have generally decreased since 2021. The quality-assured, complete, and
certified 2023-2025 design values are below the 2010 1-hour
SO<INF>2</INF> standard of 75 ppb at all four monitoring sites. As
shown in Table 3, since 2022, the annual 99th percentile daily maximum
1-hour SO<INF>2</INF> concentration has remained below the standard at
all four monitors. The significant decrease in monitored ambient
SO<INF>2</INF> concentrations is due to the implementation of the
measures at Eastman discussed in section V.A and V.C.3.
Table 2--1-Hour SO2 Three-Year Design Values (ppb) for the Sullivan County Nonattainment Area for 2017-2019 to 2023-2025
--------------------------------------------------------------------------------------------------------------------------------------------------------
Site name AQS ID 2017-2019 2018-2020 2019-2021 2020-2022 2021-2023 2022-2024 2023-2025
--------------------------------------------------------------------------------------------------------------------------------------------------------
Ross N. Robinson............................... 47-163-6001 79 63 49 41 38 38 41
Skyland Dr..................................... 47-163-6002 55 38 27 27 27 29 26
Andrew Johnson School.......................... 47-163-6003 *ND *ND 87 71 67 57 57
Happy Hill..................................... 47-163-6004 *ND *ND 53 51 52 49 49
--------------------------------------------------------------------------------------------------------------------------------------------------------
*ND: No data available. The Andrew Johnson School monitor began operation on January 1, 2019, and the Happy Hill monitor began operation on October 10,
2018. As a result, both monitors did not have complete three-year design values until 2019-2021.
Table 3--Annual 99th Percentile Daily Maximum 1-Hour SO2 Monitored Concentrations (ppb) for the Sullivan County Nonattainment Area for 2017-2025
--------------------------------------------------------------------------------------------------------------------------------------------------------
Site name AQS ID 2017 2018 2019 2020 2021 2022 2023 2024 2025
--------------------------------------------------------------------------------------------------------------------------------------------------------
Ross N. Robinson................................ 47-163-6001 92 86 59 45 42 36 37 40 45
Skyland Dr...................................... 47-163-6002 78 57 30 27 24 29 28 30 21
Andrew Johnson School........................... 47-163-6003 *ND *ND 104 73 84 55 61 56 54
Happy Hill...................................... 47-163-6004 *ND *ND 52 46 61 45 51 50 45
--------------------------------------------------------------------------------------------------------------------------------------------------------
*ND: No data available. The Andrew Johnson School monitor began operation on January 1, 2019, and the Happy Hill monitor began operation on October 10,
2018.
[[Page 68083]]
Preliminary monitoring data from the Sullivan County SO<INF>2</INF>
monitors for 2026 indicates that all four monitors continue to meet the
standard.\91\ The EPA is proposing to determine that the Sullivan
County Area has attained the 2010 1-hour SO<INF>2</INF> NAAQS based on
the modeling analysis discussed below, as well as the quality-assured,
complete, and certified ambient air monitoring data for the 2023-2025
design value period where monitoring values are below the applicable
NAAQS.
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\91\ Preliminary 2026 air monitoring data is available at
<a href="https://www.epa.gov/outdoor-air-quality-data">https://www.epa.gov/outdoor-air-quality-data</a>.
---------------------------------------------------------------------------
Tennessee has committed in its June 18, 2025, SIP revision to
continue operation of an ambient SO<INF>2</INF> monitoring network in
the Area in accordance with the air monitoring regulations in 40 CFR
part 58 to continue to verify the Area meets the SO<INF>2</INF> NAAQS.
Any future changes to the State and Local Air Monitoring Stations
network in the Sullivan County Area will be submitted to the EPA for
approval in Tennessee's annual ambient air monitoring network plan, as
required by 40 CFR 58.10.
b. Modeling Analysis
As discussed above, Tennessee's February 9, 2023, submission
contains a modeling analysis to demonstrate that the Area has attained
the 2010 SO<INF>2</INF> NAAQS as a result of compliance with the new
and existing SO<INF>2</INF> emissions limits for sources at Eastman and
Primester. This modeling analysis is resubmitted in the June 18, 2025,
submission. When the EPA designated the Sullivan County Area as a
nonattainment area for the 2010 SO<INF>2</INF> NAAQS, the Agency
determined that Eastman was the primary cause of the 2010
SO<INF>2</INF> NAAQS violations in the Sullivan County Area. Details
regarding the modeling analysis are summarized in the following
paragraphs. A more detailed discussion of TDEC's modeling can be found
in the EPA's Sullivan County SO<INF>2</INF> Modeling TSD, which is
included in the docket for this NPRM.
TDEC's modeling analysis was developed in accordance with the EPA's
Guideline on Air Quality Models (Modeling Guideline) \92\ and the
Modeling Guidance provided in appendix A of the EPA's SO<INF>2</INF>
Nonattainment Area Guidance. The modeling was performed using the EPA's
preferred air dispersion modeling system--the American Meteorological
Society/Environmental Protection Agency Regulatory Model (AERMOD)--
consisting of the AERMOD (version 22112) air dispersion model \93\ and
multiple data input preprocessors as described below.
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\92\ See 40 CFR part 51 Appendix W. For additional information
on the November 29, 2024, final Appendix W revision rule, see
<a href="https://www.epa.gov/scram/2024-appendix-w-final-rule">https://www.epa.gov/scram/2024-appendix-w-final-rule</a>.
\93\ AERMOD version 22112 was the current version available at
the time the modeling was performed by TDEC in 2023.
---------------------------------------------------------------------------
TDEC used regulatory default options in the AERMOD modeling. Based
upon an evaluation of the land use within three kilometers of Eastman,
more than 50 percent of the land use is classified under urban land use
categories rather than rural land use categories. Therefore, urban
dispersion coefficients were used in the modeling. Due to the larger
amount of heat released from Eastman, although the facility is located
in a city with a population of about 50,000, a surrogate population
value of 200,000 was calculated by Eastman for use with the urban
option in AERMOD as the ``effective population.'' Additional details
about the procedures used for the urban option are provided in the
EPA's Sullivan County SO<INF>2</INF> Modeling TSD.
AERMET and AERMINUTE are data pre-processors for the EPA's AERMOD
air quality dispersion model, generating meteorological observations
and wind data information, respectively. AERMET (version 22112) and
AERMINUTE (version 15272) were used to process one year (April 2012-
March 2013) of site-specific meteorological data \94\ (wind speed and
direction, temperature, and turbulence parameters), collected at a 100-
meter tower equipped with a Sound Detection and Ranging (SODAR) wind
profiler system specifically installed near Eastman for this modeling
analysis. Additional meteorology inputs needed for AERMOD that were not
collected at the site-specific meteorology station (e.g., cloud cover
data) were obtained from the Bristol/Johnson/Kingsport, Tri-Cities
Regional Airport (KTRI) National Weather Service (NWS) automated
surface observing system (ASOS) station (WBAN No. 13877), in
combination with twice daily upper-air meteorological soundings from
the Nashville, Tennessee NWS station (WBAN No. 13897). The Tri-Cities
Regional Airport is located approximately 8.5 miles east/southeast of
Eastman, and the Nashville Airport is located approximately 200 miles
west of Kingsport, but it has mean mixing heights comparable to the
Kingsport area. The pre-processor AERSURFACE (version 20060) was used
to process 2011 National Land Cover Database (NLCD) data to derive the
albedo, Bowen ratio, and surface roughness surface characteristics
needed for AERMET.
---------------------------------------------------------------------------
\94\ As discussed in Section 8.4.2.e of the EPA's Guideline on
Air Quality Models in 40 CFR part 51, Appendix W, if at least 1-year
of site-specific meteorology data is available, it is preferred for
use in air quality modeling analyses. Prior to the data being
collected by Eastman in 2012-2013, Eastman and TDEC consulted with
the EPA about using a partial year in 2012 and partial year in 2013
to meet the 1-year of site-specific data requirement. The EPA
concurred that it was not necessary for the 1-year of data to
correspond to a single calendar-year (January-December). The April
2012-March 2013 site-specific data continues to be the best
available wind, temperature and turbulence data for the modeling
analysis because data for these parameters from the nearby Tri-
Cities Regional Airport NWS site is located outside the river valley
where Eastman is located, so the parameters measured at the airport
are not representative of the conditions at the facility location.
---------------------------------------------------------------------------
The pre-processor AERMAP (version 18081) was used to generate
terrain inputs for the receptors, based on a digital elevation mapping
database from the National Elevation Dataset developed by the U.S.
Geological Survey. Model receptors were placed at 50-meter intervals
along the fence-line, public access roads, and riverbanks as well as in
a 100-meter grid throughout the remainder of the three-km non-
attainment area (excluding the area inside the Eastman fence-line
because access is controlled by fences, gates, and other restrictions
to limit public access and is therefore not considered to be ambient
air).
TDEC's modeling analysis is based upon permitted allowable
emissions limits for the primary SO<INF>2</INF> emissions sources at
Eastman \95\ and the other nearby sources that are included in the
modeling.\96\ Smaller SO<INF>2</INF> emissions sources at Eastman,
which will not have emissions limits incorporated into the SIP, were
modeled at maximum uncontrolled hourly emissions rates. One batch
chemical manufacturing source at Eastman was excluded from the modeling
analysis based upon the intermittent nature of its operation.
Additional details about this intermittent source are provided in
Tennessee's May 20, 2026, supplement to the redesignation request SIP
submittal and the EPA's Sullivan County SO<INF>2</INF> Modeling TSD.
The allowable emissions limits for the B-83 and B-325 coal-fired
boilers, B-248 liquid and solid hazardous waste incinerator, and B-351
Coal Gasification
[[Page 68084]]
Flares are 30-day average SO<INF>2</INF> emissions limits. The modeling
analysis must be based upon the maximum allowable 1-hour SO<INF>2</INF>
emissions. Therefore, TDEC used the procedures contained in EPA's
SO<INF>2</INF> Nonattainment Area Guidance to determine the short-term
1-hour critical emission value (CEV) for each of these sources based on
modeling and then established comparably stringent LTA permit limits.
As described in the SO<INF>2</INF> Nonattainment Area Guidance, the CEV
is the maximum modeled emission rate that results in attainment and can
be used as a reference point for setting the longer term emission
rates. Modeling multiple sources of emissions together to determine the
worst-case attainment scenario will result in a CEV associated with
each source.
---------------------------------------------------------------------------
\95\ The primary SO<INF>2</INF> emissions sources at Eastman are
B-83 and B-325 Coal-Fired Boilers, B-253 Natural Gas Boilers, B-248
Solid and Liquid hazardous waste incinerators, B-334 Incinerator for
Acid Gas Removal and Sulfur Recovery Plan, B-351 Coal Gasification
Flares, B-55 Organic Acids and Anhydrides Manufacturing Vents, and
Primester B-441 Vent C Cellulose. The emissions limits that will be
incorporated in the SIP are provided in Table 4-4 of TDEC's June 18,
2025, submission.
\96\ The nearby sources include Primester, Domtar, and Cardinal
Glass.
---------------------------------------------------------------------------
As discussed in the LTA TSD, TDEC derived longer term emission
limits from modeled CEVs for three sets of emission sources. For the
coal-fired boilers (B-83 and B-325), Tennessee established a new
single, combined emission limit of 1,248 lb/hr of SO<INF>2</INF>
emissions on a 30-day rolling average. TDEC derived this limit from the
CEV of 1,600 lb/hr and an adjustment factor of 0.78. An adjustment
factor is the ratio that accounts for the variability of the hourly
emissions for a source. For the hazardous waste incinerators (B-248-1
and B-248-2), Tennessee established separate CEVs for each of the
incinerators at 20 lb/hr and 10 lb/hr, respectively. After determining
the CEVs for each incinerator, Tennessee followed the SO<INF>2</INF>
Nonattainment Area Guidance to establish comparably stringent 30-day
rolling average emission limits for each incinerator at 15.2 lb/hr
(adjustment factor of 0.76) and 2.0 lb/hr (adjustment factor of 0.2),
respectively. For the Coal Gasification Flares (B-351-5), Tennessee
established a longer term emission limit of 14.6 lb/hr on a 30-day
rolling average. This emission limit was derived from the CEV of 16.28
lb/hr of SO<INF>2</INF> emissions. Additional details about the process
for determining the CEVs and 30-day average permit limits are contained
in the EPA's Sullivan County SO<INF>2</INF> Modeling TSD and LTA TSD.
The Building Profile Input Program for Plume Rise Model
Enhancements (BPIPPRM) (version 04274) preprocessor was used to
generate direction-specific building downwash parameters for input into
AERMOD. The stack heights used in the modeling meet the Good
Engineering Practice stack height criteria specified in 40 CFR 51.118.
Twenty-four buildings/structures were processed for the four primary
boiler stacks at Eastman (B-83 Boilers B-18-22, B-83 Boilers B-23-24,
B-325, and B-253). TDEC's modeling also evaluated the potential
building downwash effects from these same twenty-four buildings/
structures for smaller emissions sources at Eastman, and the Primster,
Domtar and Cardinal Glass facilities. The BPIPPRM results indicated
that these buildings influenced modeled concentrations for a total of
31 modeled Eastman sources and the Primester source. Building downwash
was not found to influence concentrations from the other nearby sources
included in the modeling analysis (Domtar and Cardinal Glass) because
of their distance from the nonattainment area (1 km and 23 km,
respectively).
TDEC evaluated other large sources of SO<INF>2</INF> emissions
within 50 km of the nonattainment area and determined that three
additional facilities--Primester, Domtar, and Cardinal Glass--could
potentially impact modeled SO<INF>2</INF> concentrations in the
nonattainment area based upon the magnitude of their emissions and/or
their distance from the nonattainment area. Primester has a relatively
small amount of SO<INF>2</INF> emissions (1.1 tons/year) but is located
in the nonattainment area and adjacent to Eastman. Domtar (6.95 tons/
year in 2022) and Cardinal Glass (421.58 tons/year in 2022) are located
outside the nonattainment area.
To account for SO<INF>2</INF> impacts from other emissions sources
not directly included in the AERMOD modeling analysis, TDEC used
background SO<INF>2</INF> concentrations obtained from monitoring data
collected at the Mammoth Cave National Park ambient SO<INF>2</INF>
monitor near Bowling Green, Kentucky (AQS ID: 21-061-0501). TDEC used
data from 2019-2021 to calculate hourly varying ``season-by-hour-of-
day'' background concentrations for input into AERMOD.\97\ Additional
details about the process for determining the background concentrations
are included in the EPA's Sullivan County SO<INF>2</INF> Modeling TSD.
The Mammoth Cave monitor is approximately 320 km from Eastman, and TDEC
determined that it is representative of the Area based upon the
similarity of terrain and mix of sources similar to those in the
Sullivan County Area.
---------------------------------------------------------------------------
\97\ The 2019-2021 data was the most-recent three-year dataset
available at the time the modeling was performed by TDEC in 2023.
---------------------------------------------------------------------------
Table 4 shows that the maximum modeled 99th percentile daily 1-hour
SO<INF>2</INF> concentration using the one year of representative site-
specific meteorological data (April 2012-March 2013) is less than or
equal to the 2010 SO<INF>2</INF> NAAQS of 75 ppb based on the 1-hour
CEV emission rates for the sources with LTA limits and permitted
allowable or maximum uncontrolled emissions for the other sources
included in the modeling.
Table 4--Maximum Modeled 99th Percentile Daily Maximum 1-Hour SO2 Impacts in the Sullivan County Area
----------------------------------------------------------------------------------------------------------------
Maximum predicted
Averaging time impact Background Total SO2 NAAQS
----------------------------------------------------------------------------------------------------------------
1-hour.......................... 74.82 ppb......... Included in the 74.82 ppb......... 75 ppb.
modeling.
----------------------------------------------------------------------------------------------------------------
The final modeling resulted in a highest predicted 99th percentile
daily maximum 1-hour concentration of 74.82 ppb with no modeled
violations of the 2010 SO<INF>2</INF> NAAQS in ambient air locations in
the Sullivan County Area. Additional details about the modeling are
provided in the EPA's Sullivan County SO<INF>2</INF> Modeling TSD.
Additionally, the modeled demonstration described above is consistent
with CAA requirements, the EPA's Modeling Guideline at 40 CFR part 51,
Appendix W, and the SO<INF>2</INF> Nonattainment Area Guidance.
Therefore, the EPA proposes to determine that the air quality modeling
and related information contained in TDEC's February 9, 2023, and June
18, 2025, submission demonstrates that the Sullivan County Area has
attained the 2010 SO<INF>2</INF> NAAQS as a result of compliance with
the permit limits at Eastman and Primester.
[[Page 68085]]
2. Criterion (2)--EPA Has Fully Approved the Applicable Implementation
Plan Under CAA Section 110(k); and Criterion (5)--Tennessee Has Met All
Applicable Requirements Under Title I of the CAA Section 110 and Part
D.
For redesignating a nonattainment area to attainment, the CAA
requires the EPA to determine that the State has met all applicable
requirements under section 110 and part D of title I of the CAA in
accordance with CAA section 107(d)(3)(E)(v) and that the State has a
fully approved SIP under CAA section 110(k) for the area in accordance
with CAA section 107(d)(3)(E)(ii). As discussed further in the
following subsections of this NPRM, the EPA has already approved SIP
revisions addressing certain applicable requirements under CAA section
110 and part D and is proposing to approve other revisions addressing
the remaining applicable requirements for the Sullivan County Area.\98
99\ In today's proposed action, the EPA is proposing to approve these
outstanding elements and is proposing to find that, if the Agency
finalizes approval of the outstanding CAA part D elements, the June 18,
2025, redesignation request satisfies CAA sections 107(d)(3)(E)(ii) and
(v).
---------------------------------------------------------------------------
\98\ The remaining applicable elements are sections 172(c)(1)
(RACM/RACT), 172(c)(2) (RFP), 172(c)(4) (identification and
quantification requirements), 172(c)(6) (requirement to include
other control measures as may be necessary or appropriate to provide
for attainment of such standard by the applicable attainment date),
and 172(c)(9) (contingency measures).
\99\ The EPA may rely on prior SIP approvals in approving a
redesignation request, see Wall v. EPA, 265 F.3d 426 (6th Cir.
2001), plus any additional measures that may need to be approved in
conjunction with a redesignation action.
---------------------------------------------------------------------------
a. General SIP Requirements
General SIP elements and requirements are delineated in section
110(a)(2) of title I, part A of the CAA. These requirements include,
but are not limited to, the following: submission of a SIP that has
been adopted by the State after reasonable public notice and hearing;
provisions for establishment and operation of appropriate procedures
needed to monitor ambient air quality; implementation of a source
permit program; provisions for the implementation of part C
requirements (PSD); provisions for the implementation of part D
requirements (NNSR); provisions for air pollution modeling; and
provisions for public and local agency participation in planning and
emission control rule development.
CAA section 110(a)(2)(D) requires that SIPs contain certain
measures to prevent sources in a State from significantly contributing
to air quality problems in another State. To implement this provision,
the EPA has required certain States to establish programs to address
the interstate transport of air pollutants. CAA section 110(a)(2)(D)
requirements for a State are not linked with a particular nonattainment
area's designation and classification in that State. The transport SIP
submission requirements, where applicable, continue to apply to a State
regardless of the designation of any one area in the State. As a
result, the EPA maintains that the CAA's interstate transport
requirements should be construed to be applicable for purposes of
redesignation.
In addition, the other CAA section 110(a)(2) elements that are
neither connected with nonattainment plan submissions nor linked with
an area's attainment status are not applicable requirements for purpose
of redesignation. The area will still be subject to these requirements
after the area is redesignated. CAA section 110 and part D requirements
which are linked with a particular area's designation and
classification are the relevant measures to evaluate in reviewing a
redesignation request. This approach is consistent with the EPA's
existing policy on applicability (i.e., for redesignations) of
conformity and oxygenated fuels requirements, as well as with CAA
section 184 ozone transport requirements.\100\ However, the EPA has
approved Tennessee's SIP revisions related to the CAA section 110
requirements for the 2010 SO<INF>2</INF> NAAQS, including the
interstate transport elements at CAA section 110(a)(2)(D)(i)(I).\101\
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\100\ See 61 FR 53174 (Oct. 10, 1996), 62 FR 24826 (May 7,
1997), 61 FR 20458 (May 7, 1996), and 60 FR 62748 (Dec. 7, 1995);
see also 65 FR 37890 (June 19, 2000) and 66 FR 50399 (Oct. 19,
2001).
\101\ The EPA approved Tennessee's section 110 infrastructure
SIP with respect to the 2010 1-hour SO<INF>2</INF> NAAQS. See 81 FR
85410 (Nov. 28, 2016), 83 FR 48237 (Sept. 24, 2018), and 88 FR 53800
(Aug. 9, 2023).
---------------------------------------------------------------------------
b. Title I, Part D, Applicable SIP Requirements
As discussed in section V.B. of this NPRM, the EPA is proposing to
fully approve Tennessee's February 9, 2023, second SO<INF>2</INF>
nonattainment SIP submission under CAA section 110(k) as satisfying all
the applicable requirements of title 1 under CAA sections
110(a)(2)(D)(i)(I), 110(a)(2)(I), 110(a)(2)(K), 110(l), 172, and 179.
3. Criterion (3)--The Air Quality Improvement in the Sullivan County
Area Is Due to Permanent and Enforceable Emission Reductions
As discussed above, the CAA requires the EPA to determine that the
air quality improvement in the area is due to permanent and enforceable
reductions in emissions resulting from implementation of the SIP,
applicable Federal air pollution control regulations, and other
permanent and enforceable reductions \102\ to redesignate a
nonattainment area to attainment. As discussed in section V.A of this
NPRM, the EPA proposes to determine that the reduction in monitored
SO<INF>2</INF> concentrations and the modeled attainment in the
Sullivan County Area are due to emission reductions resulting from
compliance with the control measures at Eastman that are identified for
incorporation into the SIP and those that are already incorporated into
the SIP as of December 11, 2025. The EPA is proposing to approve the
measures from TDEC's February 9, 2023, second nonattainment plan and
June 18, 2025, redesignation request, as supplemented on January 27,
2026, and May 20, 2026, as discussed in section V.A of this NPRM.
Tennessee's June 18, 2025, submission also identifies SIP-approved
State measures, some of which implement Federal requirements, that have
been implemented to date. Those measures specifically regulate coal-
fired boilers and hazardous waste incinerators.
---------------------------------------------------------------------------
\102\ See CAA section 107(d)(3)(E)(iii).
---------------------------------------------------------------------------
The control measures identified for incorporation into the SIP have
resulted in significant reductions in SO<INF>2</INF> emissions at
several Eastman emission sources. Tennessee's June 18, 2025, submission
assesses the SO<INF>2</INF> emission reductions achieved in the Area
resulting from implementation and compliance with control measures. The
submission shows that the improvement in air quality is attributed to
the control measures that the EPA is proposing to make permanent and
enforceable in the SIP and those that are already incorporated into the
SIP as of December 11, 2025. Table 5, below, shows the change in actual
SO<INF>2</INF>
[[Page 68086]]
emissions for Eastman's coal-fired boilers at Powerhouses B-253, B-83,
and B-325 between 2011 and 2022 \103\ based on the implementation of
the control measures discussed in section V.A. The largest point
sources of SO<INF>2</INF> in the Sullivan County Area are from
Eastman's coal-fired boilers which cumulatively account for over 99
percent of the SO<INF>2</INF> emissions in the Area. Overall,
SO<INF>2</INF> emissions from Eastman's coal-fired boilers decreased by
84.8 percent between 2011 and 2022.
---------------------------------------------------------------------------
\103\ See Table 4-1 in Tennessee's June 18, 2025, submission.
The 2011 actual emissions represent the base year inventory for the
Eastman coal-fired boilers before Sullivan County was designated
nonattainment for the SO<INF>2</INF> NAAQS. Calendar year 2011
represents one of three calendar years for 2009 through 2011 that
informed the EPA's SO<INF>2</INF> nonattainment designations in
2013. As discussed above, the EPA approved the 2011 base year
inventory for the Area pursuant to CAA section 172(c)(3). Calendar
year 2017 accounts for the level of SO<INF>2</INF> emissions at
Eastman coal-fired units that reflect the partial implementation of
the Area's control strategy with the completion of repowering three
of five B-253 to natural gas. Calendar year 2022 emissions represent
full implementation of the Area's control strategy (i.e., complete
repowering of all five B-253 boilers to natural gas and the
installation of DSI for B-83 boilers and 23 and 24).
Table 5--Eastman Actual Emissions From Coal-Fired Boilers and Hazardous Waste Incinerators
----------------------------------------------------------------------------------------------------------------
SO2 emissions (tons) Total
------------------------------ emissions Percent change
Source type Description reduced (tons) [2011-2022]
2011 2017 2022 [2011-2022]
----------------------------------------------------------------------------------------------------------------
Coal-Fired Boiler............. B-83, Boilers B- 5,686 4,447 2,227 3,459 -60.83
18 through B-24.
B-253, Boilers B- 14,897 4,779 7.34 14,890 -99.95
25 through B-29.
B-325, Boilers B- 1,276 1,340 1,100 176 -13.79
30 through B-31.
---------------------------------------------------------------
Totals....... 21,859 10,566 3,334 18,524 -84.75
----------------------------------------------------------------------------------------------------------------
Hazardous Waste Incinerators * B-248-1......... 20 40 3.44 16.56 -82.80
B-248-2......... 20 20 0.46 19.54 -97.70
---------------------------------------------------------------
Totals....... 40 60 3.90 36.10 -90.25
----------------------------------------------------------------------------------------------------------------
* According to TDEC, the decrease in emissions from Eastman's incinerators were primarily the result of the sale
of Eastman's adhesive resins business (the source of sulfur-containing waste in the incinerator feed) in 2022,
and the emissions limits will ensure that SO2 emissions from the incinerators do not interfere with the
attainment or maintenance of the SO2 NAAQS in the future.
4. Criterion (4)--The Sullivan County Area Has a Fully Approved
Maintenance Plan Pursuant to CAA Section 175A
For redesignating a nonattainment area to attainment, the CAA
requires the EPA to determine that the area has a fully approved
maintenance plan pursuant to CAA section 175A.\104\ In conjunction with
its request to redesignate the Sullivan County Area to attainment for
the 2010 1-hour SO<INF>2</INF> NAAQS, Tennessee submitted a SIP
revision to provide for the maintenance of the 2010 SO<INF>2</INF>
standard for at least 10 years after the effective date of
redesignation to attainment. The EPA proposes to find that this
maintenance plan meets the requirements for approval under CAA section
175A for the reasons discussed below.
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\104\ See CAA section 107(d)(3)(E)(iv).
---------------------------------------------------------------------------
CAA section 175A sets forth the elements of a maintenance plan for
areas seeking redesignation from nonattainment to attainment. Pursuant
to CAA section 175A, the plan must demonstrate continued attainment of
the applicable NAAQS for at least 10 years after the Administrator
approves a redesignation to attainment. Eight years after the
redesignation, the State must submit a revised maintenance plan
demonstrating that attainment will continue to be maintained for the 10
years following the initial 10-year period. To address the possibility
of future NAAQS violations, the maintenance plan must contain
contingency measures as the EPA deems necessary to assure prompt
correction of any future 2010 1-hour SO<INF>2</INF> violations. The
Calcagni Memorandum \105\ provides further guidance on the content of a
maintenance plan, explaining that a maintenance plan should address
five requirements: the attainment emissions inventory; maintenance
demonstration; monitoring plan; verification of continued attainment;
and a contingency plan. As discussed more fully below, the EPA proposes
to find that Tennessee's maintenance plan includes all the necessary
components and is thus proposing to approve it as a revision to the
Tennessee SIP.
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\105\ ``Procedures for Processing Requests to Redesignate Areas
to Attainment,'' Memorandum from John Calcagni, Director, Air
Quality Management Division, September 4, 1992 (hereinafter referred
to as the ``Calcagni Memorandum''), available at <a href="https://www.epa.gov/ground-level-ozone-pollution/procedures-processing-requests-redesignate-areas-attainment">https://www.epa.gov/ground-level-ozone-pollution/procedures-processing-requests-redesignate-areas-attainment</a>.
---------------------------------------------------------------------------
a. Attainment Emissions Inventory
As discussed in section V.C.1 of this NPRM, the Sullivan County
Area demonstrated attainment of the 2010 1-hour SO<INF>2</INF> standard
based on a combination of air quality monitoring and dispersion
modeling.
Currently, the Area has an attaining design value for the 2010
SO<INF>2</INF> standard based on quality-assured monitoring data for
the three-year period from 2023-2025.\106\ Tennessee selected 2022 as
the base year (i.e., attainment emissions inventory year), which is one
of the years in a three-year design value where Sullivan County
monitored attainment of the SO<INF>2</INF> standard.\107\ The
attainment inventory identifies a level of emissions in the Area that
is sufficient to attain the 2010 SO<INF>2</INF> NAAQS. Consistent with
CAA section 175A, Tennessee selected 2037 as the projected or future
maintenance year. Tennessee relied on several emission data sources to
develop the 2022 base
[[Page 68087]]
year including the 2016v1 \108\ and 2016v2 \109\ Emissions Modeling
Platforms (EMP); the 2017 and 2020 National Emissions Inventories
(NEI); \110\ and the EPA's Motor Vehicle Emissions Simulator (MOVES)
model (version 3.0.3).\111\
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\106\ Final air quality design values for all criteria
pollutants, including SO<INF>2</INF>, are available at <a href="https://www.epa.gov/air-trends/air-quality-design-values">https://www.epa.gov/air-trends/air-quality-design-values</a>. These design
values are calculated in accordance with 40 CFR part 50.
\107\ All Eastman boiler add-on controls (i.e., repowering of B-
253 Boilers 25 through 29 from coal to natural gas operation and
installation of dry sorbent injection on B-83 Boilers 23 and 24) and
new combined boiler SO<INF>2</INF> emission limit were implemented
by 2022. Overall, boiler emissions decreased by 84.7% between 2011
and 2022 as a result of Eastman's control strategy. Following
implementation of the control strategy, no exceedances of the NAAQS
were measured at the four ambient air monitors in the Area for the
first time in 2022. See Table 4 above and section 4.0 of TDEC's 2015
redesignation SIP submission.
\108\ The 2016v1 inventory is available online at <a href="https://www.epa.gov/air-emissions-modeling/2016v1-platform">https://www.epa.gov/air-emissions-modeling/2016v1-platform</a>. The CSV file
containing the area source inventory
(2016fh_proj_from_2014NEIv2_NONPOINT_final_20180119_08aug2019_nf_v1.c
sv) is available at <a href="https://gaftp.epa.gov/Air/emismod/2016/v1/2016emissions/2016fh_inventory_nonpoint_27sep2019.zip">https://gaftp.epa.gov/Air/emismod/2016/v1/2016emissions/2016fh_inventory_nonpoint_27sep2019.zip</a>.
\109\ The 2016v2 inventory is available online at <a href="https://www.epa.gov/air-emissions-modeling/2016v2-platform">https://www.epa.gov/air-emissions-modeling/2016v2-platform</a>. The CSV file
containing the area source inventory
(MYR_nonpt_constant_2017NEI_NONPOINT_20200415_28sep2020_v1.csv) is
available at <a href="https://gaftp.epa.gov/Air/emismod/2016/v2/2016emissions/2016fj_nonpoint_inventoryt_15sep2021.zip">https://gaftp.epa.gov/Air/emismod/2016/v2/2016emissions/2016fj_nonpoint_inventoryt_15sep2021.zip</a>.
\110\ See <a href="https://www.epa.gov/air-emissions-modeling/2022v1-emissions-modeling-platform">https://www.epa.gov/air-emissions-modeling/2022v1-emissions-modeling-platform</a>.
\111\ See <a href="https://www.epa.gov/moves/moves3-update-log#MOVES3.0.3">https://www.epa.gov/moves/moves3-update-log#MOVES3.0.3</a>.
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Tennessee developed the 2022 attainment inventory by first
generating a baseline emissions inventory for the Area starting with
the actual emissions submitted annually to the NEI for 2022. With the
exception of the point source category, TDEC apportioned the Area's
county-level attainment and future year emissions in the Sullivan
County Area using the 9.3 percentage ratio derived from the 2010 Census
Bureau Population data for the entire Sullivan County to the estimated
population of the Area.\112\ Table 6, below, summarizes the 2022
attainment and 2037 projected emission inventory for the Area which is
composed of five source categories: point, area (or non-point), on-road
mobile, non-road mobile, and locomotive/rail emissions.\113\ TDEC used
emission data sets and information used by the EPA to develop the
2016v1 and 2016v2 emissions inventories to project attainment year
emissions for 2022. For most source classification codes, Tennessee
calculated a growth factor as the difference between 2026 and 2016
emissions, based on the equation below:
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\112\ Tennessee derived the percentage by using a population-
weighted allocation of emissions of the entire county compared to
the nonattainment area. See Figure B-1 and Table B-4 in Tennessee's
June 18, 2025, submission.
\113\ The non-road category in this inventory excludes
locomotive and rail emissions; thus, Tennessee provided these
emissions as a separate source category. See Table 5-9 in
Tennessee's June 18, 2025, submission.
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Growth Factor = (2026 emissions-2016 emissions)/10.
For each year between 2017 and 2022, TDEC calculated emissions for
all source categories except point sources by adding the growth factor
to the base year (2016) and to each subsequent year. For on-road and
non-road sources, Tennessee obtained 2022 and 2037 mobile source
emissions by interpolation for 2022 and extrapolation for 2037 of the
existing data assuming a constant rate of year-over-year change (i.e.,
assuming emissions decrease by a constant percentage of the previous
year's emissions rather than a constant tonnage).\114\ A summary of
Tennessee's 2022 attainment and 2037 projected emission inventory for
all five source categories is provided in Table 6, below. A
comprehensive description of how Tennessee developed these inventories
is discussed in the State's June 18, 2025, submission with supporting
documentation located in Attachments A, B, C, and D.
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\114\ This method assumes that the rate of change for
SO<INF>2</INF> emissions is logarithmic rather than linear, so
mobile source emissions approach a minimum value over time without
reaching zero. See Figure 5-3 in Tennessee's June 18, 2025,
submission. Using the 2017 base year as an initial condition and
2027 as a checkpoint, the year-over-year change was numerically
determined so that the projected 2027 emissions matched the value of
the 2027 MOVES output. Using a year-over-year change of 13.25%,
mobile source emissions for each year between 2018 and 2037 were
determined in accordance with Equation 5-1 in Tennessee's June 18,
2025, submission.
Table 6--Summary of 2022 and 2037 Emissions Inventories by Source Category
----------------------------------------------------------------------------------------------------------------
2022 SO2 emissions Projected 2037 SO2 emissions
Source category (tons) (tons)
----------------------------------------------------------------------------------------------------------------
Point................................................... 3,368.1 7,338.1
Area.................................................... 4.22 3.42
On-road Mobile.......................................... 0.84 0.10
Non-road Mobile (Excluding Locomotive/Rail)............. 0.089 0.036
Locomotive/Rail......................................... 0.0039 0.0069
-------------------------------------------------------
Total Emissions..................................... 3,373 \115\ 7,342
----------------------------------------------------------------------------------------------------------------
i. Point Source Emissions: For point source emissions, Tennessee
relied on the annual emissions submitted to NEI for 2022. There are
only two point sources located in the Sullivan County Area--Eastman and
Primester. Eastman is the largest point source, and the 2022 actual
emissions for the facility are summarized in Attachment A of
Tennessee's June 18, 2025, submission. Eastman's coal-fired boilers
were responsible for nearly all SO<INF>2</INF> emissions from the
facility (approximately 98-99 percent), as indicated in Table 5-1 of
Tennessee's June 18, 2025, submission. Eastman's SO<INF>2</INF>
emissions have declined substantially following implementation of the
control strategy based on the completion of coal-fired to natural gas
conversion of all five B-253 boilers (Boilers 25-29), the installation
of a permanent DSI controls at Boilers B-23 and B-24 of Eastman's
oldest coal-fired B-83 powerhouse, and a combined 30-day rolling
SO<INF>2</INF> emission limit for Eastman's B-83 and B-325 powerhouses.
See section V.A.3 of this NPRM. The other SO<INF>2</INF> point source
in the Area, Primester, operates a cellulose acetate manufacturing
process southwest of Eastman. This facility includes one SO<INF>2</INF>
emission source, the Cellulose Scrap Recovery Process, which is
controlled by a wet scrubber. Primester is not subject to the annual or
triennial air emissions reporting requirements pursuant to 40 CFR part
51, subpart A. Thus, actual emissions from this source were assumed to
be equivalent to the emission limit of 0.25 lb/hr (1.1 tons/year) that
EPA is proposing to incorporate into the SIP.
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\115\ The point source inventory, which comprises the vast
majority of the SO<INF>2</INF> emissions for the Area, includes
potential to emit rather than projected actual emissions in 2037 for
Eastman and Primester, the Area's point sources. The State is
relying on air quality modeling to demonstrate ongoing maintenance.
See section V.B.4.b--Maintenance Demonstration below for a detailed
explanation why the Area's 2037 total projected SO<INF>2</INF>
emissions is greater than the 2022 attainment year inventory. See
also section 5.2.1.1 in Tennessee's June 18, 2025, submission.
---------------------------------------------------------------------------
In Tennessee's June 18, 2025, submission, TDEC also assessed
historical actual SO<INF>2</INF> emissions for large SO<INF>2</INF>
emitting sources at Eastman. For the 2011 first base year inventory
from Tennessee's May 11, 2017, nonattainment SIP, TDEC reported 21,859
tons of actual SO<INF>2</INF> emissions for the Area from emission
units B-253, B-
[[Page 68088]]
83, and B-325, during which time no enforceable control measures were
installed or operational and the Area was not attaining the
SO<INF>2</INF> NAAQS. The 2017 second base year inventory from
Tennessee's February 9, 2023, attainment demonstration reflected the
partial natural gas conversion at B-253 for Boilers B-30 and B-31 from
2014 to 2017 resulting in incremental emission reductions when
comparing the years 2011 and 2017. Table 7, below, provides the
historic emissions data (i.e., actuals and percentage of allowable
emissions). This table shows historic emission rates from the base year
(2011) used to determine the original design value for designation
(that the EPA approved in 2021), an interim year (2017) that reflects
partial implementation of the control strategy to repower all five of
Eastman's B-253 boilers from coal to natural gas operation (by the end
of 2017, Eastman had implemented this strategy at three of the
boilers), and a final year (2022) showing full implementation of the
control strategy to repower all five B-253 boilers from coal to natural
gas operation and install dry sorbent injection on B-83 boilers 23 and
24.
Table 7--Historic SO2 Emissions for Eastman
--------------------------------------------------------------------------------------------------------------------------------------------------------
2011 Annual actual 2017 Annual actual 2022 Annual actual
Unit SO2 emissions (tons) SO2 emissions (tons) SO2 emissions (tons) Percent change,
2011-2022
--------------------------------------------------------------------------------------------------------------------------------------------------------
B-253-1............................................................ 14,897 4,779 7.37 99.95
B-83-1............................................................. 5,686 4,447 2,227 60.83
B-325-1............................................................ 1,276 1,340 1,100 13.79
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Totals......................................................... 21,859 10,566 3,334 84.75
--------------------------------------------------------------------------------------------------------------------------------------------------------
To estimate point source emissions for 2037, the vast majority of
which would be from Eastman, TDEC conservatively estimated allowable
emissions and projected growth at the plant in terms of potential to
emit--not projected actual emissions.
ii. Area Source Emissions: TDEC projected area source attainment
year emissions for 2022 using emission data sets and information the
EPA used to develop the 2016v1 and 2016v2 EMP. For most source
classification codes, Tennessee calculated a growth factor as the
difference between 2026 and 2016 emissions. For each year between 2017
and 2022, TDEC calculated future year emissions by adding the growth
factor to the base year (2016) and to each subsequent year. TDEC used
the final 2022 emissions for the attainment year emission inventory.
TDEC apportioned county-level emissions to the Area using the 9.3
percent ratio of the 2010 census population data for the entire
Sullivan County to the Area population. TDEC projected 4.22 tons of
SO<INF>2</INF> emissions for the year 2022 and 3.42 tons of
SO<INF>2</INF> emissions for the year 2037 attributable to area
sources.
iii. On-Road Emissions: TDEC estimated on-road mobile source
SO<INF>2</INF> emissions sources in the Sullivan County Area using
locally gathered information on vehicle population and miles driven in
the Area, as well as several other inputs, combined with MOVES
modeling. On-road mobile sources include emissions from motorized
vehicles that are normally operated on public roadways such as
passenger cars, motorcycles, minivans, sport-utility vehicles, light-
duty trucks, heavy-duty trucks, and buses. Tennessee obtained 2022 and
2037 mobile source emissions by interpolation for 2022 and
extrapolation for 2037 of the existing data assuming a constant rate of
year-over-year change (i.e., assuming emissions decrease by a constant
percentage of the previous year's emissions rather than a constant
tonnage).\116\ On-road mobile source emissions are included in
Attachment C of Tennessee's June 18, 2025, submission. TDEC projected
0.84 tons of SO<INF>2</INF> emissions for the year 2022 and 0.10 tons
of SO<INF>2</INF> emissions for the year 2037 attributable to on-road
mobile sources.
---------------------------------------------------------------------------
\116\ See supra Footnote 116.
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iv. Non-Road Emissions (Excluding Locomotive and Rail Emissions):
TDEC projected nonroad mobile sources (excluding locomotive and rail
emissions) for 2022 and 2037. Tennessee's non-road source category
included emissions from aircraft, commercial marine, and rail. For the
year 2022, TDEC used emission data sets and information the EPA used to
develop the 2016v1 \117\ and 2016v2 \118\ EMP emission inventories. For
each source classification code, Tennessee obtained 2022 and 2037
mobile source emissions by interpolation (for 2022) and extrapolation
(for 2037) of the existing data by assuming a constant rate of year-
over-year change (i.e., by assuming emissions increase or decrease by a
constant percentage of the previous year's emissions rather than a
constant tonnage).\119\ TDEC projected 0.089 tons of SO<INF>2</INF>
emissions for the year 2022 and 0.036 tons of SO<INF>2</INF> emissions
for the year 2037 attributable to non-road mobile sources (excluding
locomotive and rail emissions).
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\117\ The 2016v1 inventory is available online at <a href="https://www.epa.gov/air-emissions-modeling/2016v1-platform">https://www.epa.gov/air-emissions-modeling/2016v1-platform</a>. The CSV file
containing the nonroad inventory
(2016version1_nonroad_from_MOVES2014b_forAQ_aggSCC_03sep2019_nf_v3.cs
v) is available at <a href="https://gaftp.epa.gov/Air/emismod/2016/v1/2016emissions/2016fh_inventory_nonroad_27sep2019_contents.txt">https://gaftp.epa.gov/Air/emismod/2016/v1/2016emissions/2016fh_inventory_nonroad_27sep2019_contents.txt</a>.
\118\ The 2016v2 inventory is available online at <a href="https://www.epa.gov/air-emissions-modeling/2016v2-platform">https://www.epa.gov/air-emissions-modeling/2016v2-platform</a>. The CSV file
containing the nonroad inventory
(2016fj_v2platform_nonroad_from_MOVES_aggSCC_27apr2021_nf_v1.csv) is
available at <a href="https://gaftp.epa.gov/Air/emismod/2016/v2/2016emissions/2016fj_nonroad_inventory_27may2021.zip">https://gaftp.epa.gov/Air/emismod/2016/v2/2016emissions/2016fj_nonroad_inventory_27may2021.zip</a>.
\119\ This method assumes that the rate of change is logarithmic
rather than linear, so mobile source emissions approach a minimum
value over time without reaching zero. Using the 2016 base year as
an initial condition and 2026 as a checkpoint, the year-over-year
change was numerically determined so that the projected 2026
emissions matched the EPA's 2026 inventory.
---------------------------------------------------------------------------
v. Locomotive & Rail Emissions: TDEC projected locomotive and rail
SO<INF>2</INF> emissions for 2022 and 2037. Base-year emissions from
locomotives were taken from the EPA's 2020 NEI, and locomotive
emissions were counted as point, non-point, and non-road mobile
sources. The 2020 NEI for Tennessee indicates that railyard emissions
were reported as non-point emissions (SCC 2285002006, Line Haul
Locomotives: Class I Operations) and as non-road mobile source
emissions (SCC 2285002015, Railway Maintenance). The 2020 locomotive
emissions were projected to 2022 and 2037 from the 2020 base year by
assuming a 50 percent increase in emissions per decade. The 50 percent
adjustment was based on a review of other non-road categories and
determining the highest calculated emissions increase for all non-road
categories (45 percent for several types of compressed natural gas-
burning equipment). TDEC projected 0.0039 tons
[[Page 68089]]
of SO<INF>2</INF> emissions for the year 2022 and 0.0069 tons of
SO<INF>2</INF> emissions for the year 2037 attributable to locomotive
and rail sources.
b. Maintenance Demonstration
Maintenance of the 2010 1-hour SO<INF>2</INF> standard is
demonstrated either by showing that future emissions will not exceed
the level of the attainment emissions inventory year or by modeling to
show that the future mix of sources and emission rates will not cause a
violation of the NAAQS. As discussed in the SO<INF>2</INF>
Nonattainment Area Guidance, an EPA-approved demonstration of
attainment that relies on air quality dispersion modeling using maximum
allowable emissions during the 10-year maintenance period, such as
Tennessee's modeling, can generally be expected to demonstrate that the
standard will be maintained for the requisite 10 years and beyond
without regard to any changes in operations of the pertinent sources
that do not involve increases in maximum allowable emissions.\120\
---------------------------------------------------------------------------
\120\ See SO<INF>2</INF> Nonattainment Area Guidance at p. 67.
---------------------------------------------------------------------------
Tennessee elected to demonstrate maintenance of the 2010 standard
through 2037 based on the same air dispersion modeling used to show
that the Area has attained 2010 1-hour SO<INF>2</INF> standard in
accordance with CAA section 107(d)(3)(E)(i).\121\ This modeling
demonstrates continued maintenance through 2037 because it accounts for
expected growth at Eastman during the 10-year maintenance period (i.e.,
the construction and startup of three new natural gas-fired boilers and
the methanolysis plant) and conservatively assumes that the remaining
coal-fired boilers (B-83 and B-325 powerhouses) continuously operate at
their maximum allowable hourly emission rate for the entire year.\122\
These boilers are instead included at their PTE in the 2037 inventory
and in the modeling demonstration as if they will continue operating
throughout the maintenance period to conservatively account for their
continued operation through 2028. The EPA is proposing to find that the
Sullivan County Area will continue to maintain the 2010 1-hour
SO<INF>2</INF> standard through year 2037 because the relevant sources
are required to comply with permit limits that are either already
incorporated in the SIP or through this NPRM are being proposed for
incorporation into the SIP, and for which air quality modeling shows
the Area will maintain the standard.
---------------------------------------------------------------------------
\121\ Tennessee's June 18, 2025, submission includes inventories
for 2022 and 2037. Although the 2037 inventory is higher than the
2022 inventory, the 2037 inventory reflects attainment because the
2037 point source inventory is based on emissions used in the
attainment modeling. As discussed in section V.C.4.a. above, the
2022 attainment inventory is based on actual SO<INF>2</INF>
emissions from the EPA's 2022 NEI for point sources. See section
V.B.4.a above for a summary of TDEC's development of both
inventories.
\122\ The EPA also notes that TDEC conservatively included
boilers, which have since shutdown, in the modeling demonstration.
See 90 FR 57367 (Dec. 11, 2025).
---------------------------------------------------------------------------
c. Monitoring Network
Tennessee operates four SO<INF>2</INF> monitors in the Sullivan
County Area: Ross N. Robinson (AQS: 47-163-6001), Skyland Drive (AQS:
47-163-6002), Andrew Johnson Elementary School (AQS: 47-163-6003), and
Happy Hill (AQS: 47-163-6004). See Table 3 in section V.C.1.a above.
Tennessee has committed to continue operation of an ambient
SO<INF>2</INF> monitoring network in the Area in accordance with the
air monitoring regulations in 40 CFR part 58. Should changes to the
existing network become necessary in the future, including a petition
to discontinue the operation of any monitor, TDEC will consult with the
EPA prior to any modifications to ensure the necessary regulatory steps
and guidelines are met. If the EPA approves a petition to discontinue
the use of one or more monitors, Tennessee commits to resume monitoring
at any point should additional monitoring be required pursuant to 40
CFR part 58, appendix D, section 4.4. The EPA approved Tennessee's most
recent 2025 ambient air monitoring network plan on October 10,
2025.\123\
---------------------------------------------------------------------------
\123\ A copy of the EPA's letter approving the 2025 Tennessee
ambient air monitoring network plan can be found in the docket for
this NPRM.
---------------------------------------------------------------------------
d. Verification of Continued Attainment
Tennessee, through TDEC, has the legal authority to enforce and
implement all measures necessary to attain and maintain the NAAQS
pursuant to the Tennessee Air Quality Act (TCA 68-201) and TAPCR 1200-
03 and 0400-30.\124\ Tennessee also has the authority to implement the
specific control measures required to maintain the NAAQS pursuant to
the requirements established in all relevant enforceable permits,
including any supplemental updates, identified in section V.A. These
control measures and associated MRR established in the permits, will
ensure continued maintenance of the 2010 SO<INF>2</INF> NAAQS.
Tennessee's maintenance plan provides that TDEC will track the
continued attainment and maintenance of the NAAQS through air quality
monitoring as required by 40 CFR part 58 and through the implementation
and enforcement of the SIP and its control measures.
---------------------------------------------------------------------------
\124\ On June 11, 2025, the Board signed Board Order 25-012
finding that the Sullivan County Area attained the 2010
SO<INF>2</INF> NAAQS and approving the June 18, 2025, submission to
the EPA seeking redesignation of the Area. See Attachment N in the
June 18, 2025, submission.
---------------------------------------------------------------------------
e. Contingency Plan
CAA section 175A requires that a maintenance plan includes such
contingency measures as the EPA deems necessary to assure that the
State will promptly correct a violation of the NAAQS that occurs after
redesignation. The maintenance plan identifies the contingency measures
to be adopted, a schedule and a procedure for adoption and
implementation, and a time limit for action by a State. In cases where
attainment revolves around compliance of a single source or a small set
of sources with emissions limits shown to provide for attainment, the
EPA interprets ``contingency measures'' to mean that the State agency
has a comprehensive program to identify sources of violations of the
SO<INF>2</INF> NAAQS and to undertake aggressive follow-up for
compliance and enforcement, including expedited procedures for
establishing enforceable consent agreement pending the adoption of
revised SIPs.\125\ A State also identifies specific indicators to be
used to determine when the contingency measures need to be implemented.
The maintenance plan must include a requirement that a State will
implement all measures with respect to control of the pollutant that
were contained in the SIP before redesignation of the area to
attainment in accordance with CAA section 175A(d). The contingency plan
included in the maintenance plan contains triggers to determine when
contingency measures are needed and what kind of measures should be
used.
---------------------------------------------------------------------------
\125\ See SO<INF>2</INF> Nonattainment Area Guidance at p.69 and
General Preamble for the Implementation of Title I of the Clean Air
Act Amendments of 1990 57 FR 13498 (Apr. 16, 1992). TDEC has an
active compliance and enforcement program to address violations and
will continue to operate this program to identify sources of
violations of the SO<INF>2</INF> NAAQS and to undertake an
aggressive follow-up for compliance and enforcement, including
expedited procedures for establishing enforceable consent agreements
pending the adoption of revised SIPs. TDEC commits to adopt and
expeditiously implement necessary corrective actions in the event of
a violation.
---------------------------------------------------------------------------
Tennessee's maintenance plan provides a primary trigger and
contingency measures upon activation of that trigger. This language
provides that upon notification by the Tennessee Technical Secretary to
the permittee that a reference monitor in the Area has registered four
validated ambient SO<INF>2</INF>
[[Page 68090]]
concentrations in excess of the 2010 1-hour SO<INF>2</INF> NAAQS for
any calendar year \126\ during any maintenance period approved pursuant
to CAA section 175A (a) and (b), the permittee shall undertake a full
system audit of all emissions units subject to control under this plan.
The permittee must submit a written system audit report within 30 days
of the notification. The system audit report must detail the operating
parameters of all emissions units, including smaller modeled emission
units, for four 10-day periods up to and including the date upon which
the reference monitor registered each exceedance, together with
recommended provisional SO<INF>2</INF> emission control strategies for
each affected unit and evidence that these control strategies have been
deployed, as appropriate.
---------------------------------------------------------------------------
\126\ Tennessee's May 20, 2026, supplement modifies the
contingency measure primary trigger language in section 6.0 of the
redesignation SIP narrative (and Condition G4 of SIP operating
permit No. 082237 (Amendment #1)) adding the phrase ``any calendar
year'' before the phrase ``during the maintenance period'' to
clarify that Eastman is required to conduct a full system audit
should a monitor in the maintenance area record four exceedances in
any calendar year within the maintenance period. See Tennessee's May
20, 2026, SIP supplement narrative including Attachments A and B,
which is included in the docket for this NPRM.
---------------------------------------------------------------------------
Upon consultation with the Technical Secretary, the permittee shall
develop and implement operational changes as necessary to prevent
future monitored violations of the standard. These changes may include
fuel switching, physical or operational reduction of production
capacity, or other changes as appropriate. If a permit modification is
deemed necessary, any changes to existing permit conditions shall
follow the applicable procedures of TAPCR 1200-03-09. If an emission
source is found to be noncompliant with a SIP emission limit, the
Technical Secretary will, in addition to conducting enforcement
proceedings to bring the source into compliance with its SIP limit,
determine whether additional limits must be added to the SIP in
accordance with CAA section 175A.\127\
---------------------------------------------------------------------------
\127\ Tennessee's May 20, 2026, supplement modifies the
contingency measure primary trigger language in section 6.0 of the
redesignation SIP narrative (and Condition G4 of SIP operating
permit No. 082237 (Amendment #1)) replacing ``172(c)(9)'' with
``175(A)'' for the maintenance plan citation in the SIP narrative
and Condition G4 of permit No. 082237 (Amendment #1). See
Tennessee's May 20, 2026, SIP supplement narrative including
Attachments A and B, which is in the docket for this NPRM.
---------------------------------------------------------------------------
In addition to the primary trigger described above, Tennessee has a
comprehensive program to identify sources of violations of the
SO<INF>2</INF> NAAQS and will undertake an aggressive follow-up for
compliance and enforcement, including expedited procedures for
establishing enforceable consent agreements pending the adoption of
revised SIPs.\128\
---------------------------------------------------------------------------
\128\ See Section 6.0 Maintenance Plan Requirements in the June
18, 2025, submission.
---------------------------------------------------------------------------
A trigger-level response will consist of a study to determine
whether emissions from sources within the nonattainment area (or nearby
sources located outside of the nonattainment area, as appropriate) are
increasing or indicate a trend toward higher SO<INF>2</INF>
concentrations. The study would evaluate whether the trend, if any, is
likely to continue and any control measures necessary to reverse the
trend, taking into consideration ease and timing for implementation, as
well as economic and social considerations. If new control measures are
already promulgated and scheduled to be implemented at the Federal or
State level, and if those measures are determined to be sufficient to
address any increase in peak SO<INF>2</INF> concentrations, additional
local measures may be unnecessary. Tennessee will submit to the EPA an
analysis to assess whether the proposed measures are adequate to
reverse the increase in SO<INF>2</INF> concentrations and to maintain
the NAAQS within the Area. If additional controls are necessary,
Tennessee will implement the appropriate contingency measures needed to
assure future attainment of the SO<INF>2</INF> NAAQS. Contingency
measures would be adopted and implemented as expeditiously as possible,
but no later than 24 months after the triggering event. The proposed
schedule for these actions would be as follows:
<bullet> Six months to identify appropriate contingency measures,
including identification of emission sources and appropriate control
technologies;
<bullet> Between three and six months to initiate a stakeholder
process; and
<bullet> Between nine and twelve months to implement the
contingency measures. This step would include the time required to
draft rules or SIP amendments, complete the rulemaking process, and
submit the final plans to the EPA.
If a longer schedule is required to implement specific contingency
measures, then, upon selection of the appropriate measures, Tennessee
will notify the EPA of the proposed schedule and will provide
sufficient information to the EPA to demonstrate that the proposed
measures are a prompt correction of the triggering event. The selection
of emission control measures will be based on cost-effectiveness,
emission reduction potential, economic and social considerations, or
other factors that the State deems to be appropriate. Selected emission
control measures will be subject to public review, and Tennessee will
seek public input prior to selecting new emission control measures.
D. Public Notice and Anti-Backsliding
CAA section 110(l) requires that each SIP revision submitted by a
State must be adopted by a State af
[…truncated; see source link]Indexed from Federal Register on October 29, 2026.
This is legal information, not legal advice. Laws vary by jurisdiction and change frequently. Always verify current law with official sources and consult a licensed attorney in your jurisdiction for advice on your specific situation.