[Federal Register Volume 90, Number 116 (Wednesday, June 18, 2025)]
[Proposed Rules]
[Pages 25960-25968]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2025-11263]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 52
[EPA-R08-OAR-2025-0233; FRL-12746-03-R8]
Air Plan Approval; Colorado; Serious Attainment Plan RACT
Requirements for the 2008 8-Hour Ozone National Ambient Air Quality
Standards for the Denver Metro/North Front Range Nonattainment Area
AGENCY: Environmental Protection Agency (EPA).
ACTION: Proposed rule.
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SUMMARY: The Environmental Protection Agency (EPA) is proposing to
approve state implementation plan (SIP) submittals under the Clean Air
Act (CAA) that address Reasonably Available Control Technology (RACT)
requirements for the 2008 ozone National Ambient Air Quality Standards
(NAAQS) for the Denver Metro/North Front Range (DMNFR) ozone
nonattainment area. The requirements at issue relate to the area's
previous Serious nonattainment classification. The EPA is proposing
approval of the RACT SIP submittals, proposing to find that the State
has met the applicable CAA requirements for Serious area RACT, and
proposing that the State has addressed EPA's prior disapproval
concerning specific RACT determinations. In this issue of the Federal
Register the EPA is concurrently making an interim final determination
to defer application of CAA sanctions associated with the prior
disapproval. The EPA is taking this action pursuant to the CAA.
DATES: Written comments must be received on or before July 18, 2025.
ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R08-
OAR-2025-0233, to the Federal
[[Page 25961]]
Rulemaking Portal: https://www.regulations.gov. Follow the online
instructions for submitting comments. Once submitted, comments cannot
be edited or removed from https://www.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 https://www.epa.gov/dockets/commenting-epa-dockets.
Docket: All documents in the docket are listed in the https://www.regulations.gov 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
https://www.regulations.gov. 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: Matthew Lang, Air and Radiation
Division, EPA, Region 8, Mailcode 8ARD-IO, 1595 Wynkoop Street, Denver,
Colorado 80202-1129, telephone number: (303) 312-6709, email address:
[email protected].
SUPPLEMENTARY INFORMATION: In this document ``we,'' ``us,'' and ``our''
refer to the EPA.
Table of Contents
I. What action is the EPA proposing to take?
II. Background
A. 2008 8-Hour Ozone NAAQS Nonattainment Area
B. The EPA's December 8, 2023 Final Rule
III. RACT Requirements
IV. Summary of State's SIP Submittals
A. Revisions to Regulation 7, Part E and Reorganization into
Regulation 26
B. RACT Demonstration
1. Landfill/Biogas Fired RICE
2. Process Heaters
3. Cold Rolling Mill
V. Procedural Requirements
VI. The EPA's Evaluation of Colorado's SIP Submittals
A. Revisions to Regulation 7, Part E and Reorganization into
Regulation 26
B. RACT Demonstration
1. Landfill/Biogas Fired RICE
2. Process Heaters
3. Cold Rolling Mill
4. Conclusion
VII. Proposed Action
VIII. Consideration of Section 110(l) of the CAA
IX. Incorporation by Reference
X. Statutory and Executive Order Reviews
I. What action is the EPA proposing to take?
As explained below, the EPA is proposing to approve Colorado SIP
revisions stemming from four submittals related to Serious ozone
nonattainment area RACT requirements for the DMNFR area. These
submittals also include organizational SIP revisions affecting the
submitted regulations, including the relocation of existing portions of
Colorado's Regulation Number 7 (``Reg. 7'') into new standalone
regulations. The four submittals that are the subject of this action
are described below.
First, on June 26, 2023, Colorado submitted SIP revisions related
to the Moderate and Severe nonattainment requirements for the 2015 and
2008 ozone NAAQS, respectively, which included revisions to Reg. 7.\1\
The June 26, 2023 revisions to Reg. 7 do not specifically address
Serious ozone nonattainment area RACT requirements. Because the June
2023 submittal included revisions to Reg. 7, parts A and E that were
further revised by the subsequent three submittals by Colorado
described below (that are specific to Serious ozone nonattainment area
RACT requirements), the EPA is acting on all these revisions
collectively. Second, on May 23, 2024, Colorado submitted revisions to
Reg. 7 that separate out Part E of that state regulation into a new
Regulation 26 (``Reg. 26'').\2\ Third, on May 30, 2024, Colorado
submitted revisions to Reg. 26 concerning landfill/biogas fired
Reciprocating Internal Combustion Engines (RICE), as well as other
revisions related to Moderate and Severe ozone nonattainment
requirements for the 2015 and 2008 ozone NAAQS, respectively.\3\
Fourth, on April 2, 2025, Colorado submitted SIP revisions to address
outstanding RACT requirements for Serious ozone nonattainment areas
under the 2008 ozone NAAQS, which includes associated revisions to
Reg.7 and Reg. 26.\4\
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\1\ June 2023 SIP Submittal, Document Set 1 of 7, ``Submittal
Letter to EPA_Ozone SIP.'' The letter is dated June 22, 2023, but
the SIP was submitted to EPA on June 26, 2023.The portion of the
June 2023 SIP Submittal concerning Moderate ozone nonattainment
requirements was determined to be complete by EPA on September 7,
2023. The remainder of the submittal was deemed complete by
operation of law on December 22, 2023.
\2\ May 23, 2024 SIP Submittal, ``Submittal Letter to EPA_Regs
7, 24, 25, 26_signed.'' The letter is dated May 21, 2024, but the
SIP was submitted to EPA on May 23, 2024. The May 23, 2024 SIP
Submittal was deemed complete by operation of law on November 23,
2024.
\3\ May 30, 2024 SIP Submittal, ``Submittal Letter to EPA_Ozone
SIP, Regs 7, 26, AQS_signed.'' The letter is dated May 21, 2024, but
the SIP was submitted to EPA on May 30, 2024. The May 30, 2024 SIP
Submittal was deemed complete by operation of law on November 30,
2024.
\4\ April 2025 SIP Submittal, Document Set 1 of 2, ``Signed
Submittal Letter to EPA.''
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The EPA had previously finalized disapprovals with respect to SIP
revisions related to RACT requirements for refinery fuel process
heaters, a cold rolling mill, and landfill/biogas fired RICE.\5\ In
this action, and as detailed in this preamble, we are proposing to
approve the portions of the June 26, 2023, May 23, 2024, May 30, 2024,
and April 2, 2025 submittals related to the previously disapproved
state RACT regulations.
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\5\ Final Rule, Air Plan Disapproval; Colorado; RACT Elements
for the 2008 8-Hour Ozone Standard for the Denver Metro/North Front
Range Nonattainment Area; 88 FR 85511 (Dec. 8, 2023).
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The EPA is proposing to approve the May 30, 2024 revisions
establishing a revised RACT emission limitation for landfill/biogas
fired RICE. The EPA is acting on this change as a superseding revision
in recognizing that Colorado's intent is for the landfill/biogas fired
RICE regulatory provision, that was previously disapproved by the EPA,
to now be incorporated into the SIP with subsequent changes that were
made to address the disapproval. Therefore, the EPA is proposing to
approve all of Reg. 26, Part B, section II.A.4.f., including the
revised emission limitation, into the SIP. The EPA is also proposing to
approve the April 2, 2025 revisions with respect to the RACT
determinations for refinery fuel process heaters and a cold rolling
mill. We are also proposing approval of organizational SIP revisions
from the June 26, 2023 and May 23, 2024 submittals to Reg. 7 and Reg.
26 that are unrelated to the substance of Colorado's RACT
determinations, but which facilitate efficient reorganization of Reg.
7, Part E into Reg. 26 and/or that are clerical or clarifying in
nature. The portions of the four SIP submittals that the EPA is
proposing approval of in this action are summarized in table 1 of this
preamble. The remaining revisions from the June 26, 2023, May 23, 2024,
May 30, 2024 and April 2, 2025 submittals will be addressed in future
rulemakings.
[[Page 25962]]
If the EPA finalizes this rulemaking as proposed, Colorado will
have corrected the deficiencies identified in the EPA's December 8,
2023 disapproval with respect to the Serious area RACT requirement for
the 2008 ozone NAAQS. Consistent with applicable regulations,\6\ the
EPA is concurrently making an interim final determination, which also
appears in this issue of the Federal Register, to defer application of
the CAA emission offset sanction for permitting of new or modified
major sources as well as highway sanctions associated with the December
8, 2023 disapproval. The deferral is based on this proposal to approve
SIP revisions from Colorado to resolve the RACT requirement
deficiencies that were the basis for the December 8, 2023 disapproval.
If the EPA does not finalize this approval as proposed and instead
disapproves or proposes to disapprove these SIP revisions, then the
offset sanction under CAA section 179(b)(2) for permitting new or
modified major sources would apply in the DMNFR area on the later of:
(1) the date the EPA issues such a proposed or final disapproval; or
(2) July 8, 2025 (i.e., 18 months from the effective date of the
finding that started the original sanctions clock).\7\ Subsequently,
highway sanctions under section 179(b)(1) would apply in the DMNFR area
six months after the date the offset sanction is applied.\8\
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\6\ 40 CFR 52.31(d)(2)(i).
\7\ See id. In this case, the finding that started the original
sanctions clock was the disapproval issued on December 8, 2023,
which was effective on January 8, 2024.
\8\ See id.
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The basis for our proposed action is discussed in more detail
below. The State's submittals, including technical information that we
are relying on, is in the docket, available at https://www.regulations.gov, Docket ID No. EPA-R08-OAR-2025-0233.
II. Background
A. 2008 8-Hour Ozone NAAQS Nonattainment Area
On March 12, 2008, the EPA revised both the primary and secondary
NAAQS for ozone to a level of 0.075 parts per million (ppm) (based on
the annual fourth-highest daily maximum 8-hour average concentration,
averaged over 3 years).\9\ The 2008 ozone NAAQS retains the same
general form and averaging time as the 0.08 ppm NAAQS set in 1997, but
is set at a more protective level. Specifically, the 2008 8-hour ozone
NAAQS is met when the 3-year average of the annual fourth-highest daily
maximum 8-hour average ambient air quality ozone concentrations is less
than or equal to 0.075 ppm.\10\ Effective July 20, 2012, the EPA
designated any area as nonattainment that was violating the 2008 8-hour
ozone NAAQS based on the three most recent years (2008-2010) of air
monitoring data.\11\
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\9\ Final rule, National Ambient Air Quality Standards for
Ozone, 73 FR 16436 (March 27, 2008). The EPA has since further
strengthened the ozone NAAQS, but the 2008 8-hour standard remains
in effect. See Final Rule, National Ambient Air Quality Standards
for Ozone, 80 FR 65292 (Oct. 26, 2015).
\10\ 40 CFR 50.15(b).
\11\ Final rule, Air Quality Designations for the 2008 Ozone
National Ambient Air Quality Standards, 77 FR 30088 (May 21, 2012).
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Ozone nonattainment areas are classified based on the severity of
their ambient ozone levels, as determined using the area's design
value. The design value is the 3-year average of the annual fourth-
highest daily maximum 8-hour average ozone concentration at a
monitoring site.\12\ In our July 20, 2012 action, the EPA designated
the DMNFR area as nonattainment and classified the area as
Marginal.\13\ The DMNFR area did not attain the 2008 8-hour ozone NAAQS
by the applicable Marginal area attainment deadline, and accordingly
was reclassified as Moderate.\14\ After not attaining the 2008 ozone
NAAQS for subsequent attainment dates, the area was reclassified to
Serious, and then to Severe nonattainment status.\15\
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\12\ 40 CFR part 50, appendix I.
\13\ Final rule, Air Quality Designations for the 2008 Ozone
National Ambient Air Quality Standards, 77 FR 30088 (May 21, 2012)
at 30110. The nonattainment area includes Adams, Arapahoe, Boulder,
Broomfield, Denver, Douglas and Jefferson Counties, and portions of
Larimer and Weld Counties. See 40 CFR 81.306.
\14\ Final rule, Determinations of Attainment by the Attainment
Date, Extensions of the Attainment Date, and Reclassification of
Several Areas for the 2008 Ozone National Ambient Air Quality
Standards, 81 FR 26697 (May 4, 2016).
\15\ Final rule, Finding of Failure to Attain and
Reclassification of Denver Area for the 2008 Ozone National Ambient
Air Quality Standard, 84 FR 70897 (Dec. 26, 2019) (Moderate to
Serious); Final rule, Determinations of Attainment by the Attainment
Date, Extensions of the Attainment Date, and Reclassification of
Areas Classified as Serious for the 2008 Ozone National Ambient Air
Quality Standards, 87 FR 60926 (Oct. 7, 2022) (Serious to Severe);
see 40 CFR 81.306.
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B. The EPA's December 8, 2023 Final Rule
Although the area is currently classified as Severe nonattainment
for the 2008 ozone NAAQS, the present action pertains only to
outstanding requirements from the prior Serious nonattainment
classification. Among the requirements for Serious nonattainment areas,
states must submit SIP provisions to impose RACT-level emission
limitations on relevant emission sources in the nonattainment area. As
described above, on December 8, 2023, the EPA disapproved Colorado's
RACT determinations for refinery fuel process heaters, landfill/biogas
fired RICE, and a cold rolling mill. The EPA has taken action to
approve or conditionally approve other SIP revisions related to Serious
ozone nonattainment requirements.\16\
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\16\ See 88 FR 29827, 88 FR 76676, and 88 FR 85511.
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III. RACT Requirements
CAA sections 172(c)(1) and 182(b)(2) require states to include
provisions in the SIP providing for the implementation of RACT in areas
classified as Moderate nonattainment or higher for an ozone NAAQS. The
EPA has defined RACT as ``[t]he lowest emission limitation that a
particular source is capable of meeting by the application of control
technology that is reasonably available considering technological and
economic feasibility.'' \17\ For a given category of sources, or
emission units, RACT may be determined to be work practices, rather
than the application of add-on controls and/or numerical emission
limitations.\18\ The RACT requirement applies to sources of volatile
organic compound (VOC) emissions that are covered by an EPA Control
Techniques Guideline (CTG), as well as to all major stationary sources
of VOC or nitrogen oxides (NOX) emissions within a
nonattainment area.\19\ For nonattainment areas classified as Moderate,
Serious, or Severe under an ozone NAAQS, a major stationary source that
is subject to RACT is one that emits, or has the potential to emit,
100, 50, or 25 tpy or more, respectively, of VOCs or
NOX.\20\ Therefore, under the DMNFR area's Serious
nonattainment classification for the 2008 ozone NAAQS, Colorado was
required to submit SIP revisions providing for the implementation of
RACT at stationary sources subject to an EPA CTG and at major
stationary sources emitting 50 tpy or more of VOC or NOX.
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\17\ See ``Guidance for Determining Acceptability of SIP
Regulations in Non-Attainment Areas'' (Dec. 9, 1976) at p.2,
available at https://www3.epa.gov/ttn/naaqs/aqmguide/collection/cp2/19761209_strelow_ract.pdf, and 44 FR 53761, at 53762, footnote 2
(Sep. 17, 1979).
\18\ See ``Approval Options for Generic RACT Rules Submitted to
Meet the non-CTG VOC RACT Requirement and Certain NOX
RACT Requirements'' (Nov. 7, 1996), available at https://www.epa.gov/sites/production/files/2016-08/documents/shavermemogenericract_7nov1996.pdf.
\19\ See CAA section 182(b)(2).
\20\ See CAA sections 182(b), 182(c), 182(d), 182(f)(1), and
302(j).
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[[Page 25963]]
IV. Summary of State's SIP Submittals
A. Revisions to Regulation 7, Part E and Reorganization Into Regulation
26
Due to the adoption of new rules, revisions, and reorganization on
the part of the State, part of this action includes proposing to
approve the addition of regulatory provisions that are related to the
State's RACT determinations. Specifically, the State of Colorado
submitted formal SIP revisions on June 26, 2023, May 23, 2024, May 30,
2024, and April 2, 2025, which included revisions to Reg. 7 and 26.
In the June 26, 2023 submittal, among other revisions, reference
dates to the Code of Federal Regulations (CFR) concerning EPA's
National Emission Standards for Hazardous Air Pollutants, New Source
Performance Standards (NSPS), and test methods were updated in Reg. 7,
Part E, sections I.D.4.a.(i)(B), II.A.4.b.(ii), II.A.5.b.(i)(A)(2)-(3),
II.A.5.b.(i)(B)(1)-(2), II.A.5.b.(ii)(A), II.A.6.c.(ii),
II.A.7.f.(iii), and V.A.6.b.; and compliance dates were moved into the
SIP at Reg. 7, Part E, section II.A.4. for natural gas-fired and
refinery fuel-fired process heaters subject to applicable emission
limitations.\21\ Several other revisions that are clerical or
clarifying in nature were included in the June 26, 2023 submittal. Of
relevance to this proposed action, this includes revisions to Reg. 7,
Part E, sections II.A.4.a.(vii), II.A.5.a.(i), II.A.5.b.(ii)(B)(1)-(2),
II.A.5.b.(ii)(B)(6)-(7), II.A.5.b.(ii)(D)-(E), II.A.6.a.(i)-(ii), and
II.A.6.b.(viii)(F)-(G). The revisions described above are not specific
to the RACT determinations at issue in this rulemaking concerning
landfill/biogas RICE, refinery fuel process heaters, and the cold
rolling mill. However, the EPA is proposing to approve them here to
concurrently propose action on revisions from the subsequent May 23,
2024, May 30, 2024, and April 2, 2025 submittals that reorganize and
further revise the regulatory provisions.
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\21\ June 2023 SIP Submittal, Document Set 5 of 7, ``Reg Lang &
SBAP Adopted_R7'' at 82-119. The EPA is not proposing action here on
the addition to Reg. 7, Part E, section II.A.4. from the June 26,
2023 SIP submittal that concerns the May 1, 2024 compliance date for
equipment specified under sections II.A.1.d.-e. The EPA is not yet
acting on the revisions to sections II.A.1.d.-e. from the June 26,
2023 SIP submittal and will therefore propose action on the
associated revision to section II.A.4. concurrently with the
revisions to sections II.A.1.d.-e. in a future action.
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In the State's May 23, 2024 submittal, Reg. 7 was retitled from
``Control of Ozone via Ozone Precursors and Control of Hydrocarbons via
Oil and Gas Emissions (Emissions of Volatile Organic Compounds (VOC) &
Nitrogen Oxides (NOX))'' to ``Control of Emissions from Oil
and Gas Emissions Operations.'' As a result, Reg. 7, Part E was removed
from Reg. 7 and was relocated to the newly established Reg. 26,
``Control of Emissions from Engines and Major Stationary Sources.''
\22\ The State's intent for this revision was to narrow Reg. 7 to be
primarily focused on oil and gas emission controls, which necessitated
the relocation of provisions in Part E to a new standalone regulation.
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\22\ May 23, 2024 SIP Submittal, ``Adopted Language_R7'' at 241-
292, ``Adopted Language_R26.''
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After the reorganization of Reg. 7, Part E into Reg. 26, Colorado
adopted revisions to Reg. 26 parts A and B and submitted the revisions
to the EPA on May 30, 2024. The May 30, 2024 submittal includes
revisions to Reg. 26, Part B, sections II.A.4.f. and II.A.5.b.(ii)(E)
establishing an emission limitation and performance testing/portable
analyzer monitoring requirements for landfill or biogas fired RICE; and
to Reg. 26, Part B, sections II.A.7.h. and II.A.8.b.(i) relating to
recordkeeping and reporting for semi-annual portable analyzer
monitoring.\23\ Several other revisions that are clerical or clarifying
in nature were included in the May 30, 2024 submittal. Of relevance to
this proposed action, this includes revisions to Reg. 26, Part A,
section I.C. as well as Reg. 26, Part B, sections I.C.1.,
II.A.5.b.(ii)(F) and V.A.1.a.
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\23\ May 30, 2024 SIP Submittal, ``Adopted Language_R26.''
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Colorado submitted further revisions on April 2, 2025. This
submittal makes the following revisions to Reg. 26, Part B: establishes
compliance dates for process heaters subject to emission limitations,
including for refinery fuel process heaters for which Colorado adopted
regulatory revisions to implement RACT at section II.A.4.; establishes
emission limitations for refinery fuel process heaters to meet RACT, at
sections II.A.4.g.(iv)-(v); sets forth requirements for determining
compliance with applicable emission limitations for refinery fuel
process heaters, at section II.A.5.a.(iii); requires operation of a
NOX continuous emission monitoring system (CEMS) for
refinery fuel process heaters subject to emission limits to demonstrate
compliance with those limits, at section II.A.5.b.(i)(A); removed a
reference to refinery fuel process heaters at section
II.A.5.b.(ii)(B)(1) since no units that are not already equipped with
CEMS are subject to NOX emission limits that would prompt
performance testing; and establishes standards and work practice
requirements for the cold rolling mill as RACT at section IX.\24\ Other
clerical or clarifying revisions are documented in the April 2, 2025
SIP submittal, including to Reg. 26, Part B, section II.A.4.g.(i).
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\24\ April 2025 SIP Submittal, ``Reg Language Adopted R26
(redline).''
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Several additional revisions are included in Colorado's June 26,
2023, May 23, 2024, May 30, 2024, and April 2, 2025 SIP submittals, but
the EPA is not proposing action on them in this rulemaking. We will
address the remaining revisions from the four submittals in future
rulemakings.
B. RACT Demonstration
As noted previously, the revisions to Reg. 26 that are included in
Colorado's May 30, 2024 and April 2, 2025 SIP submittals were made, in
part, to implement RACT for landfill/biogas fired RICE, refinery fuel
process heaters, and a cold rolling mill. Colorado submitted these SIP
revisions to address the EPA's December 8, 2023 disapproval of the
State's RACT determinations for these categories. The State also
included a narrative discussion and analysis, including relevant
technical information, to support its RACT determinations (``2024 RACT
Demonstration'').\25\
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\25\ April 2025 SIP Submittal, Document Set 1 of 2, Technical
Support Documents at 2-36 (``2024 RACT Demonstration''). Subsequent
citations to the 2024 RACT Demonstration use the page numbers within
that document; so, for example, ``2024 RACT Demonstration at 1''
refers to the 5th page of the Technical Support Documents file.
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1. Landfill/Biogas Fired RICE
Colorado previously adopted as RACT, and EPA previously
disapproved, the numerical NOX emission limitation of 2.0
grams of NOX per horsepower-hour (g/hp-hr) from EPA's NSPS
at 40 CFR part 60, subpart JJJJ for landfill/digester gas fired engines
greater than 500 hp. This applied to units at major stationary sources
emitting 50 tons per year of NOX or more, and the emission
limitation was based on the emissions profiles of potentially subject
sources at the time of the State's rule development in 2020. Due to
certain engines being removed from service following rule development
in 2020, Colorado has adopted a revised emission limitation of 1.5 g/
hp-hr. Colorado's May 30, 2024 submittal determines that this emission
limitation is more representative of the engines that are currently in
use, and that the limitation, along with periodic performance testing
requirements,
[[Page 25964]]
implements RACT for impacted engines.\26\
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\26\ May 30, 2024 SIP Submittal, ``Adopted Language_R26'' at 29-
30.
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2. Process Heaters
Colorado's 2024 RACT Demonstration for refinery fuel process
heaters applies to heaters at the Suncor refinery, which is within the
DMNFR nonattainment area. The State individually evaluated 23 process
heaters with the potential to emit NOX of at least 5 tons
per year.\27\ The RACT Demonstration evaluates the technological and
economic feasibility of NOX control technologies including:
(1) combustion controls like low NOX burners (LNB) and
ultra-low NOX burners (ULNB); (2) post-combustion controls
like selective catalytic reduction (SCR) and selective non-catalytic
reduction (SNCR); and (3) work practices, like good combustion
practices and combustion process adjustments.\28\ As to all 23 heaters,
Colorado determined that SNCR was not RACT for these sources because it
was not technologically feasible. Colorado determined that SNCR would
not be an appropriate control because of the insufficient residence
times (the duration of the interaction between reagents and exhaust
gases) associated with unit design, and because the exhaust
temperatures for the heaters would not be conducive to effective SNCR
operation.\29\ For 13 units, the 2024 RACT Demonstration states that
burner retrofits are not technologically feasible for unit-specific
reasons, including the potential for flame length constraints, flame
impingement, and coking of burner tubes.\30\ These 13 units include the
heaters with the designations H-31, H-32, H-10, H-11, H-20, H-27, H-28,
H-29, H-30, H-201, H-401, H-402, and H-403. For those units where
burner retrofits were deemed technologically feasible, Colorado
evaluated the cost effectiveness of burner retrofits, finding that it
ranged from $51,000-$669,000 per ton of NOX removed.\31\
Therefore, Colorado determined that burner retrofits for the process
heaters with the following designations were not economically feasible
for implementation as RACT: H-17, H-19, H-22, H-1716, H-1717, H-2410,
H-101, and H-103. Concerning SCR post-combustion emission control,
Colorado's analysis presumes that SCR is technologically feasible for
all units, and instead focuses on the cost effectiveness of
retrofitting units with SCR. The State found that this cost
effectiveness ranges from $31,000-$586,000 per ton of NOX
removed. For all 23 units, Colorado determined that these costs make
SCR retrofits not economically feasible for RACT purposes.
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\27\ 2024 RACT Demonstration at 5.
\28\ Id. at 19.
\29\ Id. at 21-22.
\30\ Id. at 22-26.
\31\ Id. at 29-30.
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Considering the technological or economic infeasibility of
additional NOX control technologies, Colorado's 2024 RACT
Demonstration establishes RACT on a unit-by-unit basis based on current
operational characteristics.\32\ For two process heaters (H-1716 and H-
2410) that currently operate CEMS, the State determined that a
NOX emission limit of 40 parts per million by volume dry
(ppmvd) at 0% oxygen on a 30-day rolling average constitutes RACT.
Colorado's regulatory revisions included with the April 2, 2025 SIP
submittal require these units to continue operating the units' CEMS to
determine compliance with the established emission limit. For units
that already use LNB or ULNB, Colorado determined RACT to consist of
continued operation of the already installed NOX control
technology. Finally, for units not subject to a numerical emission
limitation, including those that are equipped with LNB/ULNB, Colorado
determined RACT to include semi-annual combustion process adjustment
requirements. These requirements include inspection of process heater
components like burners and combustion controls, and replacing/making
adjustments as appropriate.
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\32\ Id. at table 9.
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3. Cold Rolling Mill
Colorado's 2024 RACT Demonstration evaluates a range of emission
control requirements for VOC emissions produced by the cold rolling
mill. This analysis and resulting RACT determination apply to the
rolling mill at Golden Aluminum, an aluminum manufacturing facility in
the DMNFR nonattainment area. VOC emissions from the cold rolling mill
result from volatilization of mineral oil applied as a coolant/
lubricant during the milling process that thins aluminum sheets to a
specified thickness. The cold rolling mill at the facility currently
controls emissions by using low-volatility mineral oil; coolant spray
volume and temperature control with excess spray collection using hoods
and catch basins; and a purifier for control of particulate matter
emissions.\33\ The 2024 RACT Demonstration evaluates the feasibility of
additional VOC control technologies, including thermal oxidizers,
condensers, adsorbers, absorbers, and alternative lubricants. It also
estimates the cost effectiveness of controlling VOC emissions from the
cold rolling mill, both including and excluding costs from lost
production associated with the retrofits.\34\ The State arrived at this
list of potential emission controls for evaluation after reviewing
various resources like EPA's Menu of Control Measures (MCM),\35\ CTGs/
Alternative Control Techniques (ACTs),\36\ and the RACT BACT (best
available control technology) LAER (lowest achievable emission rate)
Clearinghouse (RBLC).\37\ Colorado determined the cost effectiveness of
these emission controls as the following: a thermal oxidizer, which can
reduce VOCs by more than 95%, would cost $23,520-$39,796 per ton of VOC
removed; a condenser, to provide for collection of VOCs through change
of phase, would cost $30,713-$48,637 per ton of VOC removed; a carbon
adsorber, which traps VOC on a carbon surface, would cost $128,271-
$148,551 per ton of VOC removed; and absorption, which involves
entraining VOCs within a liquid, would cost $27,211-$74,045 per ton of
VOC removed.
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\33\ 2024 RACT Demonstration at 4-5.
\34\ Id. at 12-14.
\35\ Available at https://www.epa.gov/sites/default/files/2016-02/documents/menuofcontrolmeasures.pdf.
\36\ Available at https://www.epa.gov/ground-level-ozone-pollution/control-techniques-guidelines-and-alternative-control-techniques.
\37\ Available at https://cfpub.epa.gov/rblc/index.cfm?action=Search.BasicSearch&lang=en.
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Colorado's 2024 RACT Demonstration further considers whether an
alternative, lower volatility lubricant could be utilized. The State
determined that due to a need to ensure food-grade quality of materials
produced, and because the lubricant currently in use has a relatively
high boiling point and low vapor pressure, selection of a substitute
lubricant would not be appropriate as RACT for the cold rolling
mill.\38\ Given the technological constraints on process materials and
the anticipated high costs of retrofitting the facility with additional
air pollution control equipment, Colorado's 2024 RACT Demonstration
determines that RACT for the cold rolling mill is use of the existing
low-volatility lubricant, existing temperature control requirements,
and good operational practices like controlling application rates and
preventing spills.
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\38\ 2024 RACT Demonstration at 10.
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V. Procedural Requirements
The CAA requires that states meet certain procedural requirements
before submitting a SIP revision to the EPA,
[[Page 25965]]
including the requirement that states adopt SIP revisions after
reasonable notice and public hearing.\39\ Colorado adopted the June 26,
2023 submittal following a September 17, 2022 notice of rulemaking in
the Denver Post and a December 13-16, 2022 rulemaking hearing.\40\
Colorado adopted the May 23, 2024 submittal following a January 21,
2023 notice of rulemaking in the Denver Post and an April 20, 2023
rulemaking hearing.\41\ The State adopted the May 30, 2024 submittal
following a September 30, 2023 notice of rulemaking in the Denver Post
and a December 12, 2023 rulemaking hearing.\42\ Colorado adopted the
April 2, 2025 submittal following an August 17, 2024 notice of
rulemaking in the Denver Post and a December 18-20, 2024 rulemaking
hearing.\43\
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\39\ CAA section 110(a)(2), 42 U.S.C. 7410(a)(2).
\40\ June 2023 SIP Submittal, Document Set 1 of 7, ``Denver Post
Legal Ad.''
\41\ May 23, 2024 SIP Submittal, ``Denver Post Legal Ad.''
\42\ May 30, 2024 SIP Submittal, ``Denver Post Legal Ad.''
\43\ April 2025 SIP Submittal, Document Set 1 of 2, ``Denver
Post Legal Ad.''
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VI. The EPA's Evaluation of Colorado's SIP Submittals
A. Revisions to Regulation 7, Part E and Reorganization Into Regulation
26
As discussed in section IV.A. above, and in addition to several
clerical revisions to Reg. 7, Part E, Colorado's June 26, 2023
submittal updated various reference dates to the CFR and incorporated
compliance dates into the SIP for process heaters subject to emission
limitations. While these revisions do not directly relate to the RACT
determinations evaluated in subsequent sections, the EPA is proposing
to approve them because they are relevant to subsequent submittals that
directly implement RACT requirements and/or will, if approved,
facilitate efficient relocation of regulatory provisions through
Colorado's reorganization of Reg. 7.
The EPA is also proposing to approve revisions from Colorado's May
23, 2024 SIP submittal relocating Reg. 7, Part E to Reg. 26. These
organizational revisions also are not specific to the RACT
determinations evaluated in subsequent sections, but the EPA is
proposing to approve them because subsequent regulatory revisions that
Colorado includes in the May 30, 2024 and April 2, 2025 SIP submittals,
which do relate to RACT, concern the newly established Reg. 26.
The EPA is proposing approval of the revisions to Reg. 26, parts A
and B that were included in the May 30, 2024 and April 2, 2025 SIP
submittals. Since the revisions to Reg. 26, Part A, section I.C. and to
Reg. 26, Part B, sections I.C.1., II.A.5.b.(ii)(F), and V.A.1.a. are
clerical in nature, the EPA is proposing to approve them. The May 30,
2024 revisions to Reg. 26, Part B, sections II.A.4.f. and
II.A.5.b.(ii)(E) implement Colorado's RACT determination for landfill/
biogas fired RICE. The EPA's evaluation of these revisions, including
their sufficiency in meeting RACT, is included below.
The EPA is also proposing approval of the regulatory revisions in
Colorado's April 2, 2025 submittal to Reg. 26, Part B. We are proposing
approval of the revisions to Reg. 26, Part B, section II.A.4.g.(i)
because the revision is clerical in nature. The April 2, 2025 revisions
to Reg. 26, Part B, sections II.A.4., II.A.4.g.(iv)-(v),
II.A.5.a.(iii), II.A.5.b.(i)(A), II.A.5.b.(ii)(B)(1), and IX. implement
Colorado's RACT determinations for either refinery fuel process heaters
or the cold rolling mill. These revisions are addressed in the EPA's
RACT evaluation below for the respective equipment.
Given that the revisions the EPA is evaluating span multiple SIP
submittals from Colorado, we have included table 1, detailing the
revisions from each submittal that we are proposing to approve. The
revisions in each submittal that we are not proposing action on here
will be addressed in later rulemakings. The EPA has previously proposed
approval of certain revisions from these submittals in our May 8, 2025
proposed rule at 90 FR 19447.
Table 1--Summary of EPA's Proposed Approval of Revisions to Reg. 7 and
26
------------------------------------------------------------------------
Revisions included in the EPA's proposed
Submittal approval
------------------------------------------------------------------------
June 26, 2023................. Reg. 7, Part E, sections I.D.4.a.(i)(B),
II, II.A.4, II.A.4.a.(vii),
II.A.4.b.(ii), II.A.5.a.(i),
II.A.5.b.(i)(A)(2)-(3),
II.A.5.b.(i)(B)(1)-(2),
II.A.5.b.(ii)(A), II.A.5.b.(ii)(B)(1)-
(2), II.A.5.b.(ii)(B)(6)-(7),
II.A.5.b.(ii)(D)-(E), II.A.6.a.(i)-
(ii), II.A.6.b.(viii)(F)-(G),
II.A.6.c.(ii), II.A.7.f.(iii), V.A.6.b.
May 23, 2024.................. Removal of Reg. 7, Part E; Relocation of
provisions to Reg. 26 parts A and B.
May 30, 2024.................. Reg. 26, Part A, section I.C, Reg. 26;
Part B, sections I.C.1., II.A.4.f,
II.A.5.b.(ii)(E)-(F), II.A.7.h,
II.A.8.b.(i), V.A.1.a.
April 2, 2025................. Reg. 26, Part B, sections II.A.4.,
II.A.4.g.(i), II.A.4.g.(iv)-(v),
II.A.5.a.(iii), II.A.5.b.(i)(A),
II.A.5.b.(ii)(B)(1), IX.
------------------------------------------------------------------------
Note: At this time, the EPA is not proposing action on any of the
revisions included in the June 26, 2023, May 23, 2024, May 30, 2024,
and April 2, 2025 submittals besides those identified in table 1.
Additionally, those sections marked as ``state-only'' in Colorado's
SIP submittals are not included for incorporation into the SIP.
Therefore, the EPA is not proposing action on these sections, and any
such sections which were relocated from Reg. 7 to Reg. 26 will
continue to be ``state-only.''
B. RACT Demonstration
1. Landfill/Biogas Fired RICE
The EPA's December 8, 2023 disapproval of Colorado's RACT
determination for landfill and biogas fired RICE found that the engines
subject to the selected emission limitation of 2.0 g NOX/hp-
hr could in practice, and were currently achieving lower emissions.\44\
Additionally, the EPA also found that emissions testing/monitoring
requirements to determine compliance with the emission limitation may
have been inadvertently excluded from the revised regulation.
Colorado's May 30, 2024 SIP submittal includes regulatory revisions
that establish an emission limitation of 1.5 g NOX/hp-hr at
Reg. 26, Part B, section II.A.4.f.; initial and periodic testing
requirements for landfill and biogas fired RICE at Reg. 26, Part B,
section II.A.5.b.(ii)(E); and associated recordkeeping and reporting
requirements at Reg. 26, Part B, sections II.A.7.h. and II.A.8.b.(i).
This emission limitation can be achieved by the impacted engines as
currently operated and is more stringent than that established in EPA's
NSPS for landfill/digester gas burning engines at 40 CFR part 60,
subpart JJJJ.\45\ Colorado previously evaluated the cost effectiveness
of adopting add-on emission control requirements for landfill/biogas
RICE. The State
[[Page 25966]]
determined that SCR was not economically feasible for implementation as
RACT since cost effectiveness ranged from $27,149-$99,741 per ton of
NOX removed.\46\ The EPA agrees with Colorado's conclusion
concerning the viability of the identified emission controls as RACT
for the affected engines. Additionally, owners of these engines must
perform combustion process adjustments, which require inspection of
engine components and replacement as necessary. Therefore, the EPA is
proposing to find that Colorado's revised RACT determination for
landfill and biogas fired RICE appropriately addresses the EPA's prior
disapproval, and that the RACT determination and associated regulatory
revisions to Reg. 26, Part B, sections II.A.4.f., II.A.5.b.(ii)(E),
II.A.7.h., and II.A.8.b.(i) are approvable.
---------------------------------------------------------------------------
\44\ See 88 FR 54975, 54979 (proposed rule; explaining that RACT
analyses showed that the subject facilities were meeting a lower
emission limit); 88 FR at 85511 (finalizing proposed disapproval).
\45\ 40 CFR part 60, subpart JJJJ, table 1.
\46\ See 2008 Serious RACT TSD, available within the docket.
---------------------------------------------------------------------------
2. Process Heaters
The EPA's prior disapproval of Colorado's categorical RACT
determination for refinery fuel process heaters found that the emission
limit of 0.1 lb NOX per million British Thermal Units
(mmBTU) that the State adopted was not sufficiently supported given the
lack of test data for several units.\47\ The EPA is now proposing to
approve revised determinations since we find that Colorado
appropriately established RACT on a case-by-case basis for refinery
fuel process heaters. The State made the unit-specific determinations
following consideration and subsequent exclusion of LNB/ULNB and SCR
retrofits on either the basis of technological or economic
infeasibility.\48\
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\47\ See 88 FR 54975, 54980-54981.
\48\ 2024 RACT Demonstration at 26-27, 29-30, and 32.
---------------------------------------------------------------------------
The EPA has previously explained that RACT may ``vary from source
to source due to source configuration, retrofit feasibility, operation
procedures, raw materials, and other technical or economic
characteristics of an individual source or group of sources.'' \49\
Colorado's 2024 RACT Demonstration details how the unit-specific
configuration of certain process heaters makes burner retrofit
technologically infeasible. Among other design challenges, flame length
constraints, flame impingement, and coking of burner tubes, are
identified as affecting the technological feasibility of burner
retrofit. The EPA has previously acknowledged the difficulty that
extended flame lengths, and in particular the potential for flame
impingement, present for certain process heater LNB/ULNB retrofit
applications.\50\ The EPA reviewed these acknowledgments and has found
them to still be relevant in the context of this SIP action. In
consideration of the unit-specific analyses included in Colorado's
April 2, 2025 submittal, including the evaluations provided by burner
vendors, the EPA is proposing that the aforementioned design challenges
are relevant to those process heaters that are identified in Colorado's
RACT demonstration as being poor candidates for burner retrofit.
Therefore, the EPA is proposing to find that Colorado reasonably
excluded burner retrofits as RACT for the following 13 process heaters
on the basis of technological infeasibility: H-31, H-32, H-10, H-11, H-
20, H-27, H-28, H-29, H-30, H-201, H-401, H-402, and H-403.
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\49\ See ``Guidance for Determining Acceptability of SIP
Regulations in Non-Attainment Areas,'' memorandum from Roger
Strelow, Assistant Administrator for Air and Waste Management, to
Regional Administrators, at 2 (Dec. 9, 1976).
\50\ ``Alternative Control Techniques Document--NOX
Emissions from Process Heaters (Revised),'' EPA-453/R-93-034,
September 1993 at 5-13, 5-14, and 5-23.
---------------------------------------------------------------------------
After determining the units for which burner retrofit may be
technologically feasible, the State calculated cost effectiveness at
$51,000-$669,000 per ton of NOX removed. While the CAA does
not establish a bright line figure for determining the reasonableness
of emission controls as RACT, even the most cost-effective potential
burner retrofit presented in Colorado's 2024 RACT Demonstration for
these sources, at $51,000 per ton of NOX removed, is not
economically reasonable for purposes of RACT, based on EPA's historic
approach to RACT. Concerning retrofitting units with SCR systems, the
calculated cost effectiveness ranged from $25,000-$586,000 per ton of
NOX removed. Like the economic feasibility of burner
retrofit, the EPA does not consider even the most cost-effective SCR
retrofit in Colorado's analysis at $25,000 per ton of NOX
removed to be cost effective for purposes of establishing RACT.
Colorado's 2024 RACT Demonstration estimated the costs for SCR and
burner retrofit in a manner consistent with procedures from the EPA Air
Pollution Control Cost Manual.\51\ The analysis determined the upfront
capital investment of retrofit and annualized this cost by assuming a
20-year equipment life and a 5.5% interest rate. The estimated cost
effectiveness of various control options was then calculated by summing
this value with the direct annual costs of operating the equipment as
well as associated annual administrative costs and dividing the total
dollar amount by the amount of NOX removed in tons.
Therefore, the EPA is concurring with Colorado's rejection of burner
retrofits for the following process heaters for purposes of RACT on the
basis of economic infeasibility: H-17, H-22, H-1716, H-1717, H-2410, H-
101, and H-103. The EPA also agrees with Colorado's assessment that SCR
retrofit is not appropriate for adoption as RACT for all process
heaters included in the State's analysis on the basis of economic
infeasibility.
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\51\ Available at https://www.epa.gov/economic-and-cost-analysis-air-pollution-regulations/cost-reports-and-guidance-air-pollution.
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Due to the technological and/or economic infeasibility of
retrofitting affected units, the EPA is proposing to approve Colorado's
determination that continued operation of refinery fuel process
heaters, as currently configured, represents RACT. In particular, we
are proposing to approve the following requirements as meeting RACT:
(1) semi-annual combustion process adjustments that will contribute to
proper operation and functionality of process heaters and individual
components; (2) use of LNB or ULNB as currently in use on heaters H-31,
H-37, H-2101, H-1716, H-1717, H-201, H-101, H-401, H-402, H-403, and H-
103 that will ensure continued emission reduction associated with these
burners; and (3) a numerical NOX emission limit for heaters
H-1716 and H-2410 that will ensure emissions are not in excess of 40
ppmvd. We note that in reviewing EPA's RBLC, there are several recent
entries with NOX emission limits for similar equipment used
in petroleum refining. Listed emission limitations established for
purposes of BACT \52\ range from 20 to 80 ppmv depending on emission
controls that are in use and supports Colorado's selected RACT emission
limit for heaters H-1716 and H-2410. The EPA is also proposing to
approve the April 2, 2025 revisions to Reg. 26, Part B, sections
II.A.4., II.A.4.g.(iv)-(v), II.A.5.a.(iii), II.A.5.b.(i)(A),
II.A.5.b.(ii)(B)(1) that implement the RACT determinations for refinery
fuel process heaters evaluated in this section, and which are described
in greater detail in section IV.A. of this preamble.
---------------------------------------------------------------------------
\52\ BACT emission limitations are required on major new or
modified major sources in areas that are in attainment of a NAAQS
and are generally more stringent than those required for purposes of
RACT for similar sources.
---------------------------------------------------------------------------
3. Cold Rolling Mill
Concerning the prior disapproval of the RACT SIP revisions for the
[[Page 25967]]
identified cold rolling mill in the DMNFR nonattainment area, the EPA
determined that the State had not provided a unit-specific analysis
justifying its selection as RACT. The EPA is now proposing to approve
Colorado's revised RACT determination, which includes a full analysis
of potential emission controls in consideration of EPA resources like
the MCM, CTGs, ACTs, and RBLC.
The EPA is proposing to find that Colorado reasonably excluded
installation of additional air pollution control equipment as RACT,
including regenerative thermal oxidizers, refrigerated condensers,
carbon adsorber, and heavy oil scrubbers, on the basis of economic
infeasibility. As described previously, the CAA does not establish a
specific threshold to determine the economic reasonableness of a
control technology for implementation of RACT. However, the cost
estimates in the 2024 RACT Demonstration for installation of a thermal
oxidizer, a condenser, a carbon adsorber and heavy-oil scrubber show
that addition of these controls would not be cost-effective.\53\ When
considering even the more conservative cost estimates in the 2024 RACT
Demonstration, which exclude estimated costs associated with lost
production during retrofit, the most cost-effective control technology
is thermal oxidation, at $23,520 per ton of VOC removed, which the EPA
does not consider as reasonable for implementation as RACT.
Furthermore, the EPA is proposing to find that Colorado reasonably
determined that requiring a lower volatility lubricant does not
constitute RACT because, unlike potential alternative lubricants, the
characteristics of the lubricant currently in use at the facility are
known to be well-suited to specific process conditions and to the
production of food-grade quality materials. These operational
requirements would prevent the impacted facility from readily adopting
an alternative lubricant for purposes of RACT. That is, using an
alternative rolling lubricant is not a technologically viable option
for this facility because the lubricant currently in use already has
characteristics that would minimize volatilization including a low
vapor pressure and high boiling point. An alternative lubricant would
require testing under the process conditions at the facility to ensure
specification requirements are met, such as production of food-grade
materials.
---------------------------------------------------------------------------
\53\ 2024 RACT Demonstration at 12-14.
---------------------------------------------------------------------------
Accordingly, because of the economic infeasibility of installing
additional air pollution control equipment and the technological
infeasibility of using an alternative lubricant, the EPA is proposing
to approve Colorado's determination that continued operation of the
cold rolling mill as currently configured represents RACT. The EPA is
proposing the addition of the following operational practices into the
SIP, which function to limit emissions to the level determined to
represent RACT-level control: (1) use of existing low volatility
rolling lubricant, (2) temperature control of lubricant to minimize
volatilization, and (3) good operational practices as described in
section IV.B.3. of this preamble. The EPA is also proposing to approve
the April 2, 2025 addition of Reg. 26, Part B, section IX. that
implements the RACT determination evaluated in this section for the
cold rolling mill as well as associated recordkeeping and reporting
requirements.
4. Conclusion
Based on the RACT determinations, associated regulatory revisions,
and supporting analyses submitted by Colorado, the EPA proposes to
determine that Colorado's SIP revisions fulfill the RACT requirement
for landfill/biogas fired RICE, refinery fuel process heaters, and the
cold rolling mill for the Serious nonattainment plan for the DMNFR area
for the 2008 ozone NAAQS. Final approval of the RACT determinations for
these three categories of sources would cure the EPA's prior
disapproval of the State's March 22, 2021 submittal intended to meet
the RACT requirement for the 2008 ozone NAAQS for the DMNFR Serious
nonattainment area.
VII. Proposed Action
The EPA is proposing to approve SIP revisions submitted by the
State of Colorado to address the RACT requirement for the Serious
nonattainment plan for the DMNFR area for purposes of the 2008 Ozone
NAAQS. The EPA is proposing this action based on our determination that
Colorado's RACT determinations for landfill/biogas fired RICE, refinery
fuel process heaters, and the cold rolling mill meet the requirements
of CAA section 172(c)(1) and 182(b)(2). The EPA is also proposing to
approve revisions to Colorado Reg. 7 and 26 related to the RACT
requirement, as summarized in section IV.A. of this proposed
rulemaking.
In this same issue of the Federal Register, we are also issuing an
interim final determination, effective on publication, to defer the
imposition of sanctions. Specifically, the determination will defer
application of the offset sanction for permitting of new or modified
major sources and highway sanctions for which clocks were triggered by
the EPA's December 8, 2023 disapproval of SIP revisions submitted to
address the RACT requirement for the 2008 ozone NAAQS for the DMNFR
Serious classification nonattainment area.\54\ The determination to
defer sanctions is based upon our proposed approval action detailed in
this document, with respect to the SIP submittals addressing the RACT
SIP requirement. Please see the interim final determination for further
information concerning sanctions and the basis for issuing the interim
final determination.
---------------------------------------------------------------------------
\54\ See 40 CFR 52.31(d)(2)(ii).
---------------------------------------------------------------------------
The EPA is soliciting public comments on the proposed action and
our rationale for the proposed action. We will accept comments from the
public on this proposal for the next 30 days and will consider comments
before taking final action.
VIII. 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. 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. The Colorado SIP provisions that
the EPA is proposing to approve in this action do not interfere with
any applicable requirements of the Act. Thus, the EPA is proposing to
find that the approval of portions of the State's June 26, 2024, May
23, 2023, May 30, 2024, and April 2, 2025 SIP submittals as described
in this notice of proposed rulemaking is consistent with section
110(l). Therefore, the EPA proposes to determine the CAA section 110(l)
requirements are satisfied.
IX. 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 Colorado Air Quality Control Commission Reg.
26 pertaining to the ``Control of Emissions from Engines and Major
Stationary
[[Page 25968]]
Sources'' and Reg. 7 pertaining to the ``Control of Ozone via Ozone
Precursors and Control of Hydrocarbons via Oil and Gas Emissions
(Emissions of Volatile Organic Compounds (VOC) & Nitrogen Oxides
(NOX))'' (as specified in sections IV.A. and VI.A. above).
The EPA has made, and will continue to make, these materials generally
available through https://www.regulations.gov 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).
X. 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, EPA's role is to approve state choices,
provided that they meet the criteria of the CAA.Accordingly, this
action merely approves state law as meeting Federal requirements and
does not impose additional requirements beyond those imposed by state
law.For that reason, this action:
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);
Is not subject to Executive Order 14192 (90 FR 9065,
February 6, 2025), because SIP actions are exempt from review under
Executive Order 12866;
Does not impose an information collection burden under the
provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
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.);
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);
Does not have federalism implications as specified in
Executive Order 13132 (64 FR 43255, August 10, 1999);
Is not subject to Executive Order 13045 (62 FR 19885,
April 23, 1997), because it approves a state program;
Is not a significant regulatory action subject to
Executive Order 13211 (66 FR 28355, May 22, 2001); and
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 the EPA or an Indian Tribe
has demonstrated that a Tribe has jurisdiction. The proposed 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,
Greenhouse gases, 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: June 2, 2025.
Cyrus M. Western,
Regional Administrator, Region 8.
[FR Doc. 2025-11263 Filed 6-17-25; 8:45 am]
BILLING CODE 6560-50-P