Proposed Rule2026-01324
Air Plan Approval; Montana; Revisions to Western Sugar Stipulation
Primary source
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Published
January 23, 2026
Issuing agencies
Environmental Protection Agency
Abstract
The Environmental Protection Agency (EPA) is proposing to approve revisions to the Montana State Implementation Plan (SIP). These revisions specifically address sulfur dioxide (SO<INF>2</INF>) emission limits and associated requirements related to the Western Sugar Cooperative facility in Billings, Montana. The EPA is taking this action pursuant to the Clean Air Act (CAA).
Full Text
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<title>Federal Register, Volume 91 Issue 15 (Friday, January 23, 2026)</title>
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[Federal Register Volume 91, Number 15 (Friday, January 23, 2026)]
[Proposed Rules]
[Pages 2892-2894]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2026-01324]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 52
[EPA-R08-OAR-2025-2070; FRL-13177-01-R8]
Air Plan Approval; Montana; Revisions to Western Sugar
Stipulation
AGENCY: Environmental Protection Agency (EPA).
ACTION: Proposed rule.
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SUMMARY: The Environmental Protection Agency (EPA) is proposing to
approve revisions to the Montana State Implementation Plan (SIP). These
revisions specifically address sulfur dioxide (SO<INF>2</INF>) emission
limits and associated requirements related to the Western Sugar
Cooperative facility in Billings, Montana. The EPA is taking this
action pursuant to the Clean Air Act (CAA).
DATES: Written comments must be received on or before February 23,
2026.
ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R08-
OAR-2025-2070, to the Federal Rulemaking Portal: <a href="https://www.regulations.gov">https://www.regulations.gov</a>. Follow the online instructions for submitting
comments. Once submitted, comments cannot be edited or removed from
<a href="https://www.regulations.gov">https://www.regulations.gov</a>. 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>.
Docket: All documents in the docket are listed in the <a href="https://www.regulations.gov">https://www.regulations.gov</a> index. Although listed in the index, some
information is not publicly available, e.g., CBI or other information
whose disclosure is restricted by statute. Certain other material, such
as copyrighted material, will be publicly available only in hard copy.
Publicly available docket materials are available electronically in
<a href="https://www.regulations.gov">https://www.regulations.gov</a>. Please email or call the person listed in
the FOR FURTHER INFORMATION CONTACT section if you need to make
alternative arrangements for access to the docket.
FOR FURTHER INFORMATION CONTACT: Adam Clark, Air and Radiation
Division, EPA, Region 8, Mailcode 8ARD-IO, 1595 Wynkoop Street, Denver,
Colorado 80202-1129, telephone number: (303) 312-7104, email address:
<a href="/cdn-cgi/l/email-protection#c1a2ada0b3aaefa0a5a0ac81a4b1a0efa6aeb7"><span class="__cf_email__" data-cfemail="07646b66756c296663666a4762776629606871">[email protected]</span></a>.
SUPPLEMENTARY INFORMATION: Throughout this document wherever ``we,''
``us,'' or ``our'' is used, we mean the EPA.
I. Background
On March 3, 1978 (43 FR 8962), the Laurel, Montana area was
designated as nonattainment for the 1971 primary annual and 24-hour
SO<INF>2</INF> national ambient air quality standards (NAAQS). See 40
CFR 81.327. The nonattainment area consists of an area with a two-
kilometer radius around the CHS Laurel Refinery. This designation was
based on monitored and modeled violations of the SO<INF>2</INF> NAAQS.
The EPA reaffirmed this nonattainment designation on September 11, 1978
(43 FR 40412). The 1990 CAA Amendments, enacted November 15, 1990,
again reaffirmed the nonattainment designation of Laurel with respect
to the 1971 primary SO<INF>2</INF> NAAQS. Since the Laurel
nonattainment area had a fully approved CAA title I part D plan, the
State was not required to submit a revised plan for the area under the
1990 CAA Amendments (see sections 191 and 192 of the CAA). On March 3,
1978 (43 FR 8962), those areas in the State that were meeting the 1971
SO<INF>2</INF> NAAQS, including Billings, were designated as
attainment.
The CAA requires states to submit to the EPA a SIP to assure that
the NAAQS are attained and maintained. Air quality modeling completed
in 1991 and 1993 for the Billings/Laurel area predicted that the
SO<INF>2</INF> NAAQS were not being attained, including outside of the
existing nonattainment area in Laurel and in Billings.\1\ As a result,
the EPA (pursuant to sections 110(a)(2)(H) and 110(k)(5) of the CAA)
sent a letter to the Governor of Montana, dated March 4, 1993,\2\
finding the SIP was substantially inadequate to attain or maintain the
SO<INF>2</INF> NAAQS (known as a ``SIP Call'') and requested the State
of Montana revise its previously approved SIP for the Billings/Laurel
area. In the request letter, we declared that the SIP Call would become
final agency action when we made a final determination regarding the
State of Montana's response to the SIP Call. In response, the State
submitted revisions to the SIP on September 6, 1995, August 27, 1996,
April 2, 1997, July 29, 1998, and May 4, 2000.
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\1\ As stated in the EPA's proposed federal implementation plan
(FIP), ``Laurel is located within the Yellowstone Valley
approximately 15 miles southwest of Billings. . . . Although Laurel
and Billings are 15 miles apart, the industries in Billings have
some impact on the air quality in Laurel and the industry in Laurel
has some impact on the air quality in Billings.'' 79 FR 39260-39261,
July 12, 2006.
\2\ The EPA published this letter in the Federal Register on
August 4, 1993 (58 FR 41430).
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The EPA made a final determination regarding the SIP Call when we
partially and limitedly approved and partially and limitedly
disapproved the Billings/Laurel SO<INF>2</INF> SIP revisions submitted
by the State in response to the request letter (67 FR 22168, 22173, May
2, 2002). Among the revisions that the EPA approved into the Montana
SIP with this 2002 final action was the June 12, 1998 Board Order
issued by the Montana Board of Environmental Review adopting and
incorporating the Stipulation of the Montana Department of
Environmental Quality (MDEQ) and the Western Sugar Cooperative,
including the Stipulation (hereon ``Western Sugar Stipulation'') and
Exhibit A, ``Emission Limitations and Conditions,'' to the Western
Sugar Stipulation (hereon ``Exhibit A''), and attachments to Exhibit
A.\3\
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\3\ 67 FR 22240, May 2, 2002.
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The SO<INF>2</INF> requirements in Exhibit A of the Western Sugar
Stipulation included establishing; (1) emission limits and monitoring
and reporting requirements for the boiler house stack and pulp dryer
stacks; (2) a facility-wide 190-day campaign limit, and; (3)
requirements to modify the boiler house stack and remove fuel oil
capability for the Erie City and Cleaver Brooks boilers. Although it
was not a requirement of the Western Sugar Stipulation, by 2000 the
facility had also removed the capacity to use fuel oil as a source of
combustion for the pulp dryers, replacing it with natural gas. As a
result of these changes,
[[Page 2893]]
average annual SO<INF>2</INF> emissions at Western Sugar decreased by
about 74%.\4\ On September 25, 2025, Montana submitted a SIP revision
that revises Exhibit A.
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\4\ See the spreadsheet ``Historic Emissions Data--Western
Sugar,'' in the docket for this action. The baseline (385 tons/year)
is the average annual SO<INF>2</INF> emissions from 1990-1995, as
the facility was required to remove fuel oil capability at the Erie
City and Cleaver Brooks Boilers in 1996, per the Western Sugar
Stipulation at Exhibit A, section 3(B)(2). Annual SO<INF>2</INF>
emissions from 2000 (when fuel oil had been fully replaced by
natural gas at the pulp dryer units) to 2023 averaged 99 tons/year.
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II. The EPA's Analysis of the Proposed SIP Revision
Montana's September 25, 2025 submission requested that the EPA
approve revisions to Exhibit A. Montana's proposed revisions include;
(1) removal of the continuous emission monitor and flow rate monitor
requirements on the boiler house stack; (2) replacement of the 190-day
annual campaign limit with a heat input limit; (3) removal of the
SO<INF>2</INF> emission limits and monitoring and reporting
requirements (MRR) for the pulp dryer units and the addition of a
requirement to burn natural gas, and; (4) the removal of ``facility
modifications'' requirements, which have already been completed. The
EPA's analysis of these revisions is provided below.
A. Removing Continuous Emissions Monitoring Requirements
This revision removes the requirements of section 6 of Exhibit A to
operate and maintain a continuous emission monitor and continuous stack
flow rate monitor to measure SO<INF>2</INF> concentrations from the
boiler house stack. In their September 25, 2025 submission, MDEQ
included 2011-2023 continuous emission monitoring data showing that
none of the three SO<INF>2</INF> emission limits in section 3(A)(1)(a)
of Exhibit A have been approached during that period.\5\ The submission
also includes a calculation demonstrating that, even under the most
conservative assumptions, the SO<INF>2</INF> emission limits at the
boiler house stack could not be exceeded.\6\ Western Sugar will
continue to perform an annual source test to demonstrate ongoing
compliance with the SO<INF>2</INF> emission limits at Exhibit A,
section 3(A)(1)(a). The EPA is proposing to find that these revisions
are approvable because the annual source test is sufficient to
demonstrate ongoing compliance with the boiler house stack
SO<INF>2</INF> emission limits.
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\5\ September 25, 2025 submission at pdf page 9. The maximum
recorded values during this 13-year period were below 70% of the 3-
hour SO<INF>2</INF> limit, below 60% of the 24-hour SO<INF>2</INF>
limit, and below 25% of the annual SO<INF>2</INF> limit,
respectively. Exhibit A, section 3(A)(1)(a) contains 3-hour, 24-hour
and annual SO<INF>2</INF> emission limits for the boiler house
stack.
\6\ Id. at pdf pages 8-10. The demonstration shows that at the
maximum sulfur content and maximum fuel throughput, the boiler house
stack would still meet the limits in Exhibit A, section 3(A)(1)(a),
before considering SO<INF>2</INF> reductions from the wet scrubbers.
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B. Replacing the Campaign Limit With a Heat Input Limit
This revision replaces the 190-day limit on the duration of each
operating season, previously located at section 3(C) of Exhibit A, with
an annual heat input limit on the boiler house stack of 2,237,760
MMBtu/year that was developed to correlate with the annual
SO<INF>2</INF> limit at section 3(A)(1)(a)(iii).\7\ MDEQ's submission
demonstrated that the heat input limit is protective of the annual
SO<INF>2</INF> limit for this stack.\8\ Therefore, the EPA is proposing
to approve this revision.
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\7\ Id. at pdf page 8.
\8\ Id.
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C. Removing the Emission Limits and MRR for the Pulp Dryer Units
This revision removes the SO<INF>2</INF> emission limits for the
east dryer stack and west dryer stack in section 3(A)(1) of Exhibit A,
as well as the fuel oil flowmeter, daily fuel oil and beet sulfur
analysis requirements for these units in sections 4 and 5 of Exhibit A.
All of these requirements have been replaced by the Exhibit A, section
3(A)(1)(d) requirement that only natural gas shall be used for fuel in
the pulp dryers. By 2000, Western Sugar had decommissioned and removed
the fuel oil system from the facility so that the pulp dryers no longer
had the capability to combust fuel oil.\9\ Since 2000, the pulp dryers
have since operated solely on natural gas, which emits very little
SO<INF>2</INF>.\10\ As a result, the annual maximum combined emissions
from the two pulp dryer stacks since the fuel oil system was removed is
0.027 tons/SO<INF>2</INF>, while the combined annual limit for the two
stacks in the Western Sugar Stipulation (at Exhibit A, section
3(A)(1)(b)(iii)) is 74.34 tons/SO<INF>2</INF>.\11\ Because these
emission limits and associated MRR were based on the operation of these
units using fuel oil, and because the Western Sugar Stipulation was
revised to require only natural gas be used for fuel at these units,
the EPA is proposing to find that these revisions are approvable.
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\9\ Id. at pdf page 10.
\10\ See EPA's ``AP-42: Compilation of Air Emissions Factors
from Stationary Sources'' at Chapter 1.4, in the docket for this
action, or at <a href="https://www.epa.gov/sites/default/files/2020-09/documents/1.4_natural_gas_combustion.pdf">https://www.epa.gov/sites/default/files/2020-09/documents/1.4_natural_gas_combustion.pdf</a>.
\11\ See the spreadsheet titled ``Historic Emissions Data--
Western Sugar,'' in the docket for this action. The other
SO<INF>2</INF> limits in Exhibit A, section 3(A)(1)(b) for the
combined East and West Dryer Stacks (combined) are 88.5 pounds (3-
hour) and 708 pounds (calendar day).
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D. Removing the Facility Modifications Requirements
This revision removes section 3(B) of Exhibit A, ``Facility
Modifications,'' which required the modification of the boiler house
stack and the removal of the fuel oil guns from the Erie City and
Clever Brooks boilers, such that these two boilers could only operate
using natural gas following the modification. The EPA is proposing to
approve this revision, as these modifications were completed as of
October 1, 1996.
III. Consideration of Section 110(l) of the CAA
Under section 110(l) of the CAA, the EPA cannot approve a SIP
revision if the revision would interfere with any applicable
requirement concerning attainment and reasonable further progress
toward attainment of the NAAQS, or any other applicable requirement of
the Act. To ``interfere'' means to hamper, frustrate, hinder, or impede
any applicable CAA provision.\12\ Therefore, the EPA's approval of a
SIP revision would be consistent with section 110(l) so long as
``emissions in the air are not increased,'' and ``status quo air
quality'' is preserved. The appropriate analysis under section 110(l)
is not standardized and is determined on a case-by-case basis given the
nature of the SIP revision.\13\ To demonstrate noninterference where
the EPA anticipates that a SIP revision may result in increased
emissions, a state may either substitute equivalent or greater emission
reductions in order to preserve status quo air quality or submit an air
quality analysis showing that the SIP revision will not interfere with
any applicable requirements.\14\ In addition, section 110(l) requires
that each revision to an implementation plan submitted by a state be
adopted by the state after reasonable notice and public hearing. In
evaluating Montana's submitted SIP revision, the EPA considered whether
[[Page 2894]]
approval of the revision would result in interference under CAA section
110(l).
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\12\ Bryan A. Garner, Garner's Dictionary of Legal Usage 570 (3d
ed. 2011); see also Merriam-Webster's Collegiate Dictionary 652
(11th ed. 2005) (``to interpose in a way that hinders or impedes'').
\13\ Ky. Res. Council, Inc. v. EPA, 467 F.3d 986, 991 (6th Cir.
2006); see also Indiana v. EPA, 796 F.3d 803, 806 (7th Cir. 2015);
Ala. Env't Council v. EPA, 711 F.3d 1277, 1292-93 (11th Cir. 2013);
Galveston-Houston Ass'n for Smog Prevention v. EPA, 289 F. App'x
745, 754 (5th Cir. 2008).
\14\ See Ky. Res. Council, Inc. v. EPA, 467 F.3d at 995.
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The EPA reviewed air quality design values for the Billings/Laurel
area, which demonstrate that it currently meets the more stringent 2010
primary SO<INF>2</INF> NAAQS and 2024 secondary SO<INF>2</INF> NAAQS by
a significant margin.\15\ There are no operational changes included in
the revisions that could meaningfully increase SO<INF>2</INF> emissions
at the Western Sugar facility, which is among the lower emitting
SO<INF>2</INF> sources in the Billings/Laurel area.\16\ Montana's
submittal provides adequate evidence that the provisions were adopted
after reasonable public notice and hearings. Based on these
considerations, the EPA has concluded that the September 25, 2025 SIP
revision we are proposing to approve with this action does not
interfere with any applicable requirements of the Act and that the CAA
section 110(l) requirements are satisfied.
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\15\ <a href="https://www.epa.gov/air-trends/air-quality-design-values">https://www.epa.gov/air-trends/air-quality-design-values</a>.
As this demonstrates, the maximum design value for Yellowstone
County for the most recent 2022-2024 design value period was 22 ppb
for the 1-hour NAAQS of 75 ppb, and 1 ppb for the annual NAAQS of 10
ppb.
\16\ September 25, 2025 submission at pdf page 7, Figure 1. See
also ``Historic Emissions Data--Western Sugar,'' in the docket for
this action, which shows that Western Sugar emits roughly 2% of the
total SO<INF>2</INF> emissions in Yellowstone County annually.
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IV. Proposed Action
The EPA is proposing to approve Montana's September 25, 2025
revisions to Exhibit A of the Western Sugar Stipulation into the
Montana SIP. The EPA is taking this action pursuant to the CAA.
V. Incorporation by Reference
In this document, the EPA is proposing to include regulatory text
in an EPA final rule that includes incorporation by reference. In
accordance with requirements of 1 CFR 51.5, the EPA is proposing to
incorporate by reference ``Western Sugar June 12, 1998 Exhibit A.
Emission Limitations and Other Conditions.'' The EPA has made, and will
continue to make, these materials generally available through <a href="https://www.regulations.gov">https://www.regulations.gov</a> and at the EPA Region 8 Office (please contact the
person identified in the FOR FURTHER INFORMATION CONTACT section of
this preamble for more information).
VI. Statutory and Executive Order Reviews
Under the CAA, the Administrator is required to approve a SIP
submission that complies with the provisions of the CAA and applicable
Federal regulations. 42 U.S.C. 7410(k); 40 CFR 52.02(a). Thus, in
reviewing SIP submissions, the EPA's role is to approve state choices,
provided that they meet the criteria of the CAA. Accordingly, this
action merely proposes to approve state law as meeting Federal
requirements and does not impose additional requirements beyond those
imposed by state law. For that reason, this action:
<bullet> Is not a significant regulatory action subject to review
by the Office of Management and Budget under Executive Order 12866 (58
FR 51735, October 4, 1993) and 13563 (76 FR 3821, 2011);
<bullet> Is not subject to Executive Order 14192 (90 FR 9065,
February 6, 2025) because SIP actions are exempt from review under
Executive Order 12866;
<bullet> Does not impose an information collection burden under the
provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
<bullet> Is certified as not having a significant economic impact
on a substantial number of small entities under the Regulatory
Flexibility Act (5 U.S.C. 601 et seq.);
<bullet> Does not contain any unfunded mandate or significantly or
uniquely affect small governments, as described in the Unfunded
Mandates Reform Act of 1995 (Pub. L. 104-4);
<bullet> Does not have federalism implications as specified in
Executive Order 13132 (64 FR 43255, August 10, 1999);
<bullet> Is not subject to Executive Order 13045 (62 FR 19885,
April 23, 1997) because it approves a state program;
<bullet> Is not a significant regulatory action subject to
Executive Order 13211 (66 FR 28355, May 22, 2001); and
<bullet> Is not subject to requirements of section 12(d) of the
National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272
note) because application of those requirements would be inconsistent
with the CAA.
In addition, the SIP is not approved to apply on any Indian
reservation land or in any other area where EPA or an Indian Tribe has
demonstrated that a Tribe has jurisdiction. In those areas of Indian
country, the rule does not have Tribal implications and will not impose
substantial direct costs on Tribal governments or preempt Tribal law as
specified by Executive Order 13175 (65 FR 67249, November 9, 2000).
List of Subjects in 40 CFR Part 52
Environmental protection, Air pollution control, Carbon monoxide,
Incorporation by reference, Intergovernmental relations, Lead, Nitrogen
dioxide, Ozone, Particulate matter, Reporting and recordkeeping
requirements, Sulfur oxides, Volatile organic compounds.
Authority: 42 U.S.C. 7401 et seq.
Dated: January 14, 2026.
Cyrus M. Western,
Regional Administrator, Region 8.
[FR Doc. 2026-01324 Filed 1-22-26; 8:45 am]
BILLING CODE 6560-50-P
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