`[Federal Register Volume 90, Number 5 (Wednesday, January 8, 2025)]
[Proposed Rules]
[Pages 1600-1634]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-30648]



[[Page 1599]]

Vol. 90

Wednesday,

No. 5

January 8, 2025

Part II





Environmental Protection Agency





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40 CFR Part 52





Air Plan Approval; AK, Fairbanks North Star Borough; 2006 24-Hour PM2.5 
Serious Area and 189(d) Plan; Proposed Rule

  Federal Register / Vol. 90, No. 5 / Wednesday, January 8, 2025 / 
Proposed Rules  

[[Page 1600]]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R10-OAR-2024-0595; FRL-12391-02-R10]


Air Plan Approval; AK, Fairbanks North Star Borough; 2006 24-Hour 
PM2.5 Serious Area and 189(d) Plan

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: The Environmental Protection Agency (EPA) is proposing to 
approve the state implementation plan (SIP) revisions submitted by the 
State of Alaska (Alaska or the State) on December 4, 2024, to address 
Clean Air Act requirements for the 2006 24-hour fine particulate matter 
(PM2.5) national ambient air quality standards in the 
Fairbanks North Star Borough Serious PM2.5 nonattainment 
area. Alaska's submission includes SIP revisions to meet nonattainment 
planning requirements for emissions inventories, modeling and sulfur 
dioxide precursor demonstration for major stationary sources, control 
measures, attainment projections and progress to attainment and 
associated motor vehicle emissions budgets, and contingency measures. 
The EPA is also starting the adequacy process for the budgets.

DATES: Comments. Written comments must be received on or before 
February 7, 2025.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R10-
OAR-2024-0595, at https://www.regulations.gov. 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 the disclosure of which 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.

FOR FURTHER INFORMATION CONTACT: Matthew Jentgen, EPA Region 10, 1200 
Sixth Avenue, Suite 155, Seattle, WA 98101, (206) 553-0340, 
[email protected].

SUPPLEMENTARY INFORMATION: Throughout this document wherever ``we,'' 
``us,'' or ``our'' is used, it is intended to refer to the EPA.

Table of Contents

I. Background
II. Review of the SIP Revisions to the Fairbanks Serious Plan and 
Fairbanks 189(d) Plan
    A. Emissions Inventory
    B. Pollutants Addressed
    C. Control Strategy
    D. Attainment Demonstration and Modeling
    E. Reasonable Further Progress
    F. Quantitative Milestones
    G. Contingency Measures
    H. Motor Vehicle Emission Budgets for Transportation Conformity
III. Summary of Proposed Action
    A. Proposed Approval
    B. Adequacy Process
IV. Interim Final Determination and Deferral of Sanctions
V. Incorporation by Reference
VI. Statutory and Executive Order Reviews

I. Background

    In 2009, the EPA designated a portion of the Fairbanks North Star 
Borough as ``nonattainment'' for the 2006 24-hour PM2.5 
National Ambient Air Quality Standards (NAAQS), which is set at the 
level of 35 micrograms per cubic meter ([mu]g/m\3\) (Fairbanks 
PM2.5 Nonattainment Area) (74 FR 58688, November 13, 
2009).\1\ Effective July 2, 2014, the EPA classified the area as 
``Moderate'' (79 FR 31566, June 2, 2014). Subsequently, Alaska 
submitted, and the EPA approved, a plan to meet the Moderate 
nonattainment area requirements (82 FR 42457, September 8, 2017) 
(Fairbanks Moderate Plan).
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    \1\ See 40 CFR 81.302.
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    On May 10, 2017, the EPA determined that the Fairbanks 
PM2.5 Nonattainment Area failed to attain the 2006 24-hour 
PM2.5 NAAQS in the area by the outermost statutory Moderate 
area attainment date of December 31, 2015 (82 FR 21711). The outermost 
attainment date is the latest date by which an area can attain the 
NAAQS per statute. As a result, the Fairbanks PM2.5 
Nonattainment Area was reclassified as a ``Serious'' nonattainment area 
by operation of law.
    Upon reclassification as a Serious PM2.5 nonattainment 
area, the State was required to submit a Serious area attainment plan 
satisfying the requirements of Clean Air Act (CAA or Act) sections 172, 
189(b), and 189(c) and 40 CFR 51.1003(b). In accordance with CAA 
section 188(c)(2), the outermost attainment date for a Serious area is 
no later than the end of the tenth calendar year following designation 
(i.e., December 31, 2019).
    Alaska submitted a plan to address the Serious PM2.5 
nonattainment area requirements on December 13, 2019 (Fairbanks Serious 
Plan).\2\ Along with the required planning elements, the Fairbanks 
Serious Plan included more stringent performance and operating 
requirements for residential and commercial heating devices, new 
regulations for wood sellers, and some requirements for stationary 
sources in the nonattainment area. The Fairbanks Serious Plan is 
comprised of revisions to Title 18, Chapter 50, of the Alaska 
Administrative Code (18 AAC 50) and the State Air Quality Control Plan, 
adopted and incorporated by reference into State law at 18 AAC 
50.030(a).\3\ On January 9, 2020, in accordance with CAA section 
110(k)(1)(B), the EPA determined that the Fairbanks Serious Plan was 
administratively and technically complete (85 FR 7760, February 11, 
2020).
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    \2\ We note that Alaska submitted a SIP revision on October 25, 
2018, to address the preconstruction permitting new source review 
(NSR) requirements for the Fairbanks Serious nonattainment area, 
among other things. The EPA approved the submission as meeting the 
nonattainment NSR requirements for the Fairbanks Serious Plan on 
August 29, 2019 (84 FR 45419).
    \3\ We note that 18 AAC 50.030(a) is not submitted, rather 
Alaska submits the adopted provisions separately for EPA approval.
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    Within the Fairbanks Serious Plan, the State sought an extension of 
the otherwise applicable attainment date through CAA section 188(e). On 
September 2, 2020, the EPA determined that the area failed to attain by 
the Serious area attainment date and denied the State's Serious area 
attainment date extension request (85 FR 54509). As a result, Alaska 
was required to submit a revised SIP submission to meet both the 
Serious area attainment plan requirements and the additional 
requirements set forth in CAA section 189(d) by December 31, 2020.\4\ 
Alaska submitted the revised plan on December 15, 2020 (Fairbanks 
189(d) Plan). The Fairbanks 189(d) Plan updated a number of chapters of 
the narrative portion of the State Air Quality Control Plan, adopted 
and incorporated by reference into State law at 18 AAC 50.030(a).
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    \4\ 40 CFR 51.1003(c).
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    On September 24, 2021, the EPA approved the 2013 base year 
emissions inventory and the PM2.5 precursor

[[Page 1601]]

demonstration elements of the Fairbanks Serious Plan as meeting the 
Serious area planning requirements (86 FR 52997). In the same action, 
the EPA approved other plan components as SIP strengthening, including: 
(1) the updated Fairbanks Emergency Episode Plan \5\ that the State 
adopted on November 18, 2020, and submitted on December 15, 2020; and 
(2) the regulatory control measures included in the SIP submissions on 
October 25, 2018, and November 28, 2018 (in addition to the December 
13, 2019, submission).\6\ The EPA did not determine as part of the 
September 24, 2021, approval whether these SIP strengthening components 
met specific nonattainment plan requirements, including control 
strategy requirements in CAA section 189 and 40 CFR 51.1010 or the 
contingency measure requirements in CAA section 172(c)(9) and 40 CFR 
51.1014.
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    \5\ State Air Quality Control Plan, Vol. II, section III.D.7.12 
(i.e., Alaska's planning chapter related to air quality forecasting 
and curtailment levels).
    \6\ For a description of the specific control measures addressed 
across the State's SIP submissions, see 86 FR 52997, September 24, 
2021.
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    Finally, on December 5, 2023, the EPA acted on the remaining 
elements required for a Serious nonattainment area that failed to 
attain by the Serious area attainment date. Table 1 of this preamble 
provides a summary of the December 5, 2023, final rule approving in 
part and disapproving in part the Fairbanks Serious Plan and Fairbanks 
189(d) Plan.\7\
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    \7\ 88 FR 84626, December 5, 2023.

       Table 1--Summary of the EPA's December 5, 2023, Final Rule
------------------------------------------------------------------------
   Description of CAA planning
           requirement                 Approval           Disapproval
------------------------------------------------------------------------
Base year emissions inventory     Approval of the
 for Serious areas subject to      2013 base year
 CAA section 189(b) * (CAA         emissions
 section 172(c)(3); \8\ 40 CFR     inventory.
 51.1008(b)(1)).
Base year emissions inventory     Approval of the
 for areas subject to CAA          2019 base year
 section 189(d) (CAA section       emissions
 172(c)(3); 40 CFR                 inventory.
 51.1008(c)(1)).
Attainment projected emissions    ..................  Disapproval.
 inventory (CAA section
 172(c)(1); \9\ 40 CFR
 51.1008(c)(2)).
Serious area nonattainment plan   Partial approval    Disapproval of the
 control strategy that ensures     of the control      control strategy
 that best available control       strategy as         BACM and BACT
 measures (BACM), including best   meeting BACM and    requirements (CAA
 available control technologies    BACT requirements   section
 (BACT), for the control of        under CAA section   189(b)(1)(B) \13\
 direct PM2.5 and PM2.5            189(b)(1)(B) \11\   and 40 CFR
 precursors are implemented in     and 40 CFR          51.1010(a)) for
 the nonattainment area (CAA       51.1010(a) for      the following
 section 189(b)(1)(B); \10\ 40     the solid fuel      emissions source
 CFR 51.1010(a)).                  home heating        categories: (1)
                                   device source       Requirements for
                                   category and        wood sellers; (2)
                                   residential and     Coal-fired
                                   commercial fuel     heating devices;
                                   oil combustion      (3) Coffee
                                   source category;    roasters; (4)
                                  Partial approval     Weatherization
                                   of the control      and energy
                                   strategy approved   efficiency
                                   as meeting BACM     measures; (5)
                                   and BACT            Mobile source
                                   requirements        category
                                   under CAA section   (disapproving for
                                   189(b)(1)(B) \12\   lack of vehicle
                                   and 40 CFR          anti-idling
                                   51.1010(a) for      requirements);
                                   the charbroiler,   Disapproval of the
                                   used oil burner,    control strategy
                                   and mobile source   BACM and BACT
                                   categories          requirements (CAA
                                   (except for         section
                                   rejection of        189(b)(1)(B) \14\
                                   vehicle anti-       and 40 CFR
                                   idling              51.1010(a)) for
                                   requirements);.     PM2.5 and sulfur
                                  Approval of          dioxide (SO2) for
                                   specific            the Doyon-Fort
                                   regulations under   Wainwright
                                   18 AAC 50.075       Central Heating
                                   through 077         and Power Plant,
                                   (except the         University of
                                   requirements for    Alaska Fairbanks
                                   dry wood sellers    Campus Power
                                   under 18 AAC        Plant, Zehnder
                                   50.076(k)), and     Power Plant, and
                                   Fairbanks           North Pole Power
                                   Emergency Episode   Plant.
                                   Plan (except the
                                   contingency
                                   measure portion);.
                                  Partial approval
                                   as meeting
                                   applicable
                                   control strategy
                                   BACM and BACT
                                   requirements (CAA
                                   section
                                   189(b)(1)(B) and
                                   40 CFR
                                   51.1010(a)) for
                                   ammonia (NH3) for
                                   the Chena Power
                                   Plant, Doyon-Fort
                                   Wainwright
                                   Central Heating
                                   and Power Plant,
                                   University of
                                   Alaska Fairbanks
                                   Campus Power
                                   Plant, Zehnder
                                   Power Plant, and
                                   North Pole Power
                                   Plant;
                                  Partial approval
                                   of Alaska's PM2.5
                                   and NH3 BACT
                                   determinations
                                   for the Doyon-
                                   Fort Wainwright
                                   Central Heating
                                   and Power Plant;
                                   PM2.5 and NH3
                                   BACT
                                   determination for
                                   the University of
                                   Alaska Fairbanks
                                   Campus Power
                                   Plant, except for
                                   the three small
                                   diesel fired
                                   engines (EUs 23,
                                   26, and 27);
                                   PM2.5 and NH3
                                   BACT
                                   determinations
                                   for the Zehnder
                                   Power Plant;
                                   PM2.5 and NH3
                                   BACT
                                   determinations
                                   for the North
                                   Pole Power Plant.
Additional measures (beyond       ..................  Disapproval.
 those already adopted in
 previous nonattainment plan SIP
 submissions for the area as
 RACM/RACT, BACM/BACT, and Most
 Stringent Measures (MSM) \15\
 (if applicable)) that provide
 for attainment of the NAAQS as
 expeditiously as practicable
 and, from the date of such
 submission until attainment,
 demonstrate that the plan will
 at a minimum achieve an annual
 five percent reduction in
 emissions of direct PM2.5 or
 any PM2.5 plan precursor. (CAA
 section 189(d); \16\ 40 CFR
 51.1010(c)).
Attainment demonstration and      ..................  Disapproval.
 modeling (CAA sections
 188(c)(2) and 189(b)(1)(A);
 \17\ 40 CFR 51.1003(c) and
 51.1011).
Reasonable further progress       ..................  Disapproval.
 (RFP) provisions (CAA section
 172(c)(2); \18\ 40 CFR 51.1012).
Quantitative milestones (CAA      ..................  Disapproval.
 section 189(c); \19\ 40 CFR
 51.1013).

[[Page 1602]]

 
Motor vehicle emission budgets    ..................  Disapproval.
 (CAA section 176, 40 CFR
 51.1003(d) and 93.118).
An adequate evaluation by the     Approval of the
 state of sources of all four      State's
 PM2.5 precursors for              comprehensive
 regulation, and implementation    PM2.5 precursor
 of controls on all such           demonstrations
 precursors, unless the state      for NOX and VOC
 provides a demonstration          emissions.
 establishing that it is either
 not necessary to regulate a
 particular precursor in the
 nonattainment area at issue in
 order to attain by the
 attainment date, or that
 emissions of the precursor do
 not make a significant
 contribution to PM2.5 levels
 that exceed the standard.* (CAA
 section 189(e); \20\ 40 CFR
 51.1006).
Contingency measures applicable   ..................  Disapproval of the
 to Serious areas subject to CAA                       contingency
 section 189(b) (CAA section                           measures
 172(c)(9); \21\ 40 CFR 51.1014).                      requirements of
                                                       CAA section
                                                       172(c)(9) \22\
                                                       and 40 CFR
                                                       51.1014
                                                       applicable to
                                                       Serious areas
                                                       subject to CAA
                                                       sections 189(b)
                                                       and 189(d).
Contingency measures applicable   ..................  The EPA finalized
 to Serious areas subject to CAA                       a limited
 section 189(d) (CAA section                           disapproval of
 172(c)(9); 40 CFR 51.1014).                           the Fairbanks
                                                       189(d) Plan
                                                       contingency
                                                       measure because
                                                       the contingency
                                                       measure did not
                                                       fully meet the
                                                       contingency
                                                       measure
                                                       requirements of
                                                       CAA section
                                                       172(c)(9) and 40
                                                       CFR 51.1014 but
                                                       otherwise
                                                       strengthened the
                                                       SIP.\23\
Nonattainment new source review   Approval..........
 provisions (CAA sections
 172(c)(5), 189(b)(3), 189(d),
 and 189(e), and 40 CFR 51.165,
 40 CFR 51.1003(b)(1)(viii), and
 40 CFR 51.1003(c)(1)(viii) \24\.
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* The EPA finalized approval of this requirement on September 24, 2021
  (86 FR 52997).

    On December 4, 2024, Alaska made a SIP submission (Fairbanks 
Revised 189(d) Plan) intended to address the nonattainment requirements 
that were disapproved as part of the EPA's December 5, 2023, final 
rule. CAA sections 110(a)(1) and (2) and 110(l) require each state to 
provide reasonable public notice and opportunity for public hearing 
prior to the adoption and submission of a SIP or SIP revision to the 
EPA. To meet this requirement, every SIP submission must include 
evidence that the state provided adequate public notice and an 
opportunity for a public hearing consistent with the EPA's implementing 
regulations in 40 CFR 51.102.
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    \8\ 42 U.S.C. 7502(c)(3).
    \9\ 42 U.S.C. 7502(c)(1).
    \10\ 42 U.S.C. 7513a(b)(1)(B).
    \11\ 42 U.S.C. 7513a(b)(1)(B).
    \12\ Id.
    \13\ 42 U.S.C. 7513a(b)(1)(B).
    \14\ 42 U.S.C. 7513a(b)(1)(B).
    \15\ MSM is applicable if the EPA has previously granted an 
extension of the attainment date under CAA section 188(e) for the 
nonattainment area and NAAQS at issue. The EPA denied Alaska's 
request to extend the Serious area attainment date for the Fairbanks 
PM2.5 Nonattainment Area.
    \16\ 42 U.S.C. 7513a(d).
    \17\ 42 U.S.C. 7513(c)(2) and 7513a(b)(1)(A).
    \18\ 42 U.S.C. 7502(c)(2).
    \19\ 42 U.S.C. 7513a(c).
    \20\ 42 U.S.C. 7513a(e).
    \21\ 42 U.S.C. 7502(c)(9).
    \22\ 42 U.S.C. 7502(c)(9).
    \23\ The EPA finalized a limited approval of the Fairbanks 
Emergency Episode Plan, State Air Quality Control Plan, Vol. II, 
section III.D.7.12, as SIP-strengthening on September 24, 2021. 86 
FR 52997, September 24, 2021, at pp. 52997, 53004.
    \24\ 42 U.S.C. 7502(c)(5), 7513a(b)(3), 7513a(d), and 7513a(e).
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    On March 11, 2024, Alaska notified the public of the opportunity to 
review and comment on proposed regulatory changes related to the 
Fairbanks nonattainment area and announced two formal public hearings 
on April 10, 2024. The public comment period closed on May 10, 2024. 
Later, on August 26, 2024, Alaska opened a public comment period to 
solicit public review of amendments to numerous SIP sections and 
appendices and to notify the public of two hearings scheduled on 
September 26, 2024. On September 20 and 23, 2024, Alaska opened comment 
periods for the public to review each proposed permit revision to 
implement the State's proposed regulatory changes. The comment periods 
closed on October 22 and 25, 2024, respectively. The SIP submission 
includes evidence of the public notices and copies of written and oral 
comments received, with the State's associated responses. Therefore, we 
find that the submission meets the procedural requirements for public 
notice and hearing in CAA sections 110(a) and 110(l) and 40 CFR 51.102.
    CAA section 110(k)(1)(B) requires the EPA to determine whether a 
SIP submission is complete within 60 days of receipt. This section also 
provides that any plan that the EPA has not affirmatively determined to 
be complete or incomplete will become complete by operation of law six 
months after the date of submission. The EPA reviewed the submission 
and finds it complete based on the EPA's SIP completeness criteria in 
40 CFR part 51, appendix V.\25\
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    \25\ See ``SIP Submittal Checklist for the Fairbanks North Star 
Borough PM2.5 Nonattainment Area--2024 SIP revision,'' 
EPA Region 10, Air and Radiation Division, included in the docket 
for this action.
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    Section II of this document summarizes the EPA's review of Alaska's 
SIP submission against the relevant CAA requirements. The EPA's 
technical analysis is detailed in technical support documents in the 
docket for this action.

II. Review of the SIP Revisions to the Fairbanks Serious Plan and 
Fairbanks 189(d) Plan

A. Emissions Inventory

1. Statutory and Regulatory Requirements
    CAA section 172(c)(3) requires that states submit a comprehensive, 
accurate, and current inventory of actual emissions from all sources of 
the relevant pollutant or pollutants in the nonattainment area as part 
of a nonattainment plan for such area. On August 24, 2016, the EPA 
finalized regulations implementing SIP requirements for states with 
areas designated as nonattainment for the PM2.5 NAAQS.\26\ 
This rule is codified at 40 CFR part 51, subpart Z and is referred to 
herein as the PM2.5 SIP Requirements Rule. The 
PM2.5 SIP Requirements Rule at 40 CFR 51.1008 contains the 
requirements for emissions

[[Page 1603]]

inventories.\27\ The EPA has also issued additional guidance concerning 
emissions inventories for PM2.5 nonattainment areas.\28\ In 
accordance with 40 CFR 51.1008, the attainment plan must include a base 
year emissions inventory and attainment projected emissions inventory.
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    \26\ Fine Particulate Matter National Ambient Air Quality 
Standards: State Implementation Plan Requirements, 81 FR 58010, 
August 24, 2016, at p. 58149.
    \27\ 81 FR 58010, August 24, 2016, at pp. 58078-58079.
    \28\ ``Emissions Inventory Guidance for Implementation of Ozone 
and Particulate Matter National Ambient Air Quality Standards 
(NAAQS) and Regional Haze Regulations,'' EPA, May 2017 (``Emissions 
Inventory Guidance''), available at: https://www.epa.gov/air-emissions-inventories/air-emissions-inventory-guidance-implementation-ozone-and-particulate.
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    The base year emissions inventory for a Serious PM2.5 
nonattainment area must be one of the three years for which the EPA 
used monitored data to reclassify the area to Serious, or another 
technically appropriate year justified by the state in its Serious area 
nonattainment plan SIP submission.\29\ Similarly, the base year 
emissions inventory for a nonattainment area subject to CAA section 
189(d) must be one of the three years for which monitored data were 
used by the EPA to determine the area failed to attain the 
PM2.5 NAAQS by the applicable Serious area attainment date, 
or another technically appropriate year justified by the state in its 
Serious area nonattainment plan SIP submission.\30\ The base year 
emissions inventory should provide a state's best estimate of actual 
emissions from all sources, i.e., all emissions that contribute to the 
formation of PM2.5. The emissions must be either annual 
total emissions, average-season day emissions, or both, as appropriate 
for the relevant annual versus 24-hour PM2.5 NAAQS. The 
state must include a rationale for providing annual or seasonal 
emissions inventories, and justification for the period used for any 
seasonal emissions calculations.\31\
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    \29\ 40 CFR 51.1008(b)(1).
    \30\ 40 CFR 51.1008(c)(1).
    \31\ 40 CFR 51.1008.
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    According to 40 CFR 51.1008, the Fairbanks Revised 189(d) Plan must 
include an attainment projected inventory for the nonattainment area. 
The year of the projected inventory shall be the most expeditious year 
for which projected emissions show modeled PM2.5 
concentrations below the level of the NAAQS. The emissions values shall 
be projected emissions of the same sources included in the base year 
inventory for the nonattainment area (i.e., those only within the 
nonattainment area) and any new sources. The state shall include in 
this inventory projected emissions growth and contraction from both 
controls and other causes during the relevant period. The temporal 
period of emissions shall be the same temporal period (annual, average-
season-day, or both) as the base year inventory for the nonattainment 
area. The same sources reported as point sources in the base year 
inventory for the nonattainment area shall be included as point sources 
in the attainment projected inventory for the nonattainment area. 
Stationary nonpoint and mobile source projected emissions shall be 
provided using the same detail (e.g., state, county, and process codes) 
as the base year inventory for the nonattainment area. The same detail 
of the emissions included shall be consistent with the level of detail 
and data elements as in the base year inventory for the nonattainment 
area (i.e., as required by 40 CFR part 51, subpart A). Consistent with 
the base year inventory for the nonattainment area, the inventory shall 
include direct PM2.5 emissions, separately reported 
PM2.5 filterable and condensable emissions, and emissions of 
the scientific PM2.5 precursors, including precursors that 
are not significant PM2.5 plan precursors pursuant to a 
precursor demonstration under 40 CFR 51.1006.
    A state's SIP submission must include documentation explaining how 
it calculated emissions data for the inventory and be consistent with 
the data elements required by 40 CFR part 51, subpart A.\32\ In 
estimating mobile source emissions, a state must use the latest 
emissions models and planning assumptions available at the time the SIP 
is developed.\33\ States are also required to use the EPA's 
``Compilation of Air Pollutant Emission Factors'' (``AP-42'') road dust 
method for calculating re-entrained road dust emissions from paved 
roads.34 35
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    \32\ 40 CFR 51.1008(c); (a)(1)(v); 81 FR 58010, August 24, 2016, 
at pp. 58027-29.
    \33\ See CAA section 172(c)(3).
    \34\ The EPA released an update to AP-42 in January 2011 that 
revised the equation for estimating paved road dust emissions based 
on an updated data regression that included new emissions tests 
results. 76 FR 6328 (February 4, 2011).
    \35\ AP-42 has been published since 1972 as the primary source 
of the EPA's emission factor information. https://www.epa.gov/air-emissionsfactors-and-quantification/ap-42-compilation-airemissions-factors. It contains emission factors and process information for 
more than 200 air pollution source categories. A source category is 
a specific industry sector or group of similar emitting sources. The 
emission factors have been developed and compiled from source test 
data, material balance studies, and engineering estimates.
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2. Summary of the EPA's Prior Rulemaking Regarding the Emissions 
Inventory
    On December 5, 2023, the EPA finalized approval of the base year 
emissions inventory, but the EPA finalized disapproval of the projected 
attainment year emissions inventory. The EPA stated that, due to the 
insufficient control strategy, the attainment projected emissions 
inventory did not necessarily take into consideration all required 
emissions reductions.
3. Summary of the State's Submission Regarding the Emissions Inventory
    Based on the EPA's approval of the initial Fairbanks 189(d) Plan's 
base year emissions inventory, Alaska retained State Air Quality 
Control Plan, Vol. II, section III.D.7.6.2. However, Alaska has since 
updated the modeling platform and included a 2020 base year emissions 
inventory in the Fairbanks Revised 189(d) Plan. The modeling platform 
includes key elements such as the meteorological modeling, air quality 
modeling, and model emissions inventories. The base year planning 
emissions inventory for direct PM2.5 and PM2.5 
precursors (nitrogen oxides (NOX), SO2, volatile 
organic compounds (VOC), and ammonia (NH3)) and the 
documentation for the inventory for the Fairbanks PM2.5 
Nonattainment Area are located in the updated Fairbanks Emissions 
Inventory section.\36\
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    \36\ State Air Quality Control Plan, Vol. II, section 
III.D.7.6.9.
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    For projecting attainment, the 2020 base year emissions inventory 
incorporates the ambient monitoring data used to establish the baseline 
design value. Alaska stated that the 2020 base year emissions inventory 
accounts for emissions reductions from control measures adopted and 
implemented through December 31, 2019. Projected control measure-driven 
emissions reductions are then applied to evaluate the appropriate 
attainment date. Alaska also noted that, for planning purposes, the 
base year emissions inventory represents a baseline of nonattainment 
area emissions to demonstrate five percent per year emissions 
reductions.
    Alaska stated that the Fairbanks Revised 189(d) Plan includes an 
entirely new photochemical modeling platform and, for the emissions 
inventory, features a new, more current winter 2019-2020 modeling 
episode. Episodic emissions for the 2020 base year inventory were based 
on activity collected to represent this 74-day 2019-2020 period.

[[Page 1604]]

    For point sources, day- and hour-specific fuel use for the new 
2019-2020 modeling episode were obtained by Alaska from each of the 
point source facilities within the nonattainment area. Alaska noted 
that unlike the base year emissions inventories from earlier versions 
of the nonattainment plan, which projected episodic emissions from 2008 
to 2013 and 2019, respectively, Alaska stated that the 2020 base year 
point source emissions inventory was based on the actual data during 
the modeling episodes.
    Alaska stated that, for space heating area sources, space heating 
energy usage estimates for the 2020 base year emissions inventory were 
based on a comprehensive new Fairbanks Home Heating survey, conducted 
in the spring of 2023. Respondents were asked to provide information on 
fuel usage by device in their household for the most recent two 
calendar years (2021 and 2022) as well as the six-month winter period 
between October 2022 and March 2023. Data from this 2023 survey were 
used to replace projected space heating emissions developed under 
previous SIP revisions using earlier 2011-2015 surveys. Alaska noted 
that decreases in the fraction of wood devices used in the 
nonattainment area and the amount of wood use per device from the 
survey respondents tracked well with downward trajectories of wood use 
expected from existing and on-going control programs such as the 
Fairbanks North Star Borough's (FNSB) Wood Stove Change Out Program and 
the Alaska DEC's Solid Fuel-Burning Appliance Curtailment Program. 
Alaska stated that survey results were then back-casted to calendar 
year 2020 to provide a more realistic estimate of wood-fired heating 
use for the 2020 base year emissions inventory.\37\
---------------------------------------------------------------------------

    \37\ For a description of the ``back-cast'' method, see 
Kotchenruther, Robert. (November 21, 2024). Technical support 
document for Alaska Department of Environmental Conservation's 
amendments to: State Air Quality Control Plan, Emission Inventory 
Data (version August 19, 2024). U.S. Environmental Protection 
Agency, Region 10, Laboratory Services and Applied Science Division, 
EPA-R10-OAR-2024-0595, section 1.5.
---------------------------------------------------------------------------

    For on-road and non-road mobile sources, Alaska noted that the 
previous base year emissions inventories included on-road vehicle 
populations and age distributions based on 2014 and 2018 department of 
motor vehicle (DMV) registration data, respectively. For the Fairbanks 
Revised 189(d) Plan, 2020 DMV registration data were used to align with 
the 2020 base year emissions inventory year. For on-road mobile 
sources, these 2020 DMV data were used to develop vehicle population, 
age distribution, and fuel type/technology inputs to the MOVES3 vehicle 
emissions model. For aircraft activity specifically, a recent 
adjustment to aircraft activity in the initial Fairbanks 189(d) Plan 
was made to reflect lower aircraft activity during the winter months. 
Otherwise, the estimates of aircraft activity in the Fairbanks Revised 
189(d) Plan were unchanged. Table 2 of this preamble includes a summary 
of the base year emissions inventory.

                    Table 2--2020 Base Year Episode Average Daily Emissions by Source Sector
----------------------------------------------------------------------------------------------------------------
                                                               2020 base year emissions inventory (tons/day)
                      Source sector                       ------------------------------------------------------
                                                             PM2.5       NOX        SO2        VOC        NH3
----------------------------------------------------------------------------------------------------------------
Point Sources............................................       0.58      13.54       6.63       0.04      0.888
Area, Space Heating......................................       1.97       2.17       3.61       6.66      0.109
Area, Space Heat, Wood...................................       1.89       0.23       0.04       6.55      0.067
Area, Space Heat, Oil....................................       0.06       1.72       3.54       0.10      0.003
Area, Space Heat, Coal...................................       0.00       0.00       0.00       0.00       0.00
Area, Space Heat, Other..................................       0.02       0.22       0.02       0.01      0.039
Area, Other..............................................       0.11       0.36       0.03       2.21      0.047
Mobile, On-Road..........................................       0.07       1.18      0.000       1.42      0.040
Mobile, Aircraft.........................................       0.12       0.43       5.44       0.15      0.000
Mobile, Non-Road excluding aircraft......................       0.09       0.29       0.00       2.64     0.0001
                                                          ------------------------------------------------------
    Totals...............................................       2.95      17.96      15.71      13.04      0.285
----------------------------------------------------------------------------------------------------------------
Source: State Air Quality Control Plan, Vol. II, section III.D.7.6, Table 7.6-9.

    Alaska noted for PM2.5 overall, the 2020 base year 
emissions in the Fairbanks Revised 189(d) Plan are nine percent lower 
than the 2019 base year emissions inventory in the initial Fairbanks 
189(d) Plan, with differences coming from space heating and mobile 
sources that are likely the result of on-going emissions controls.\38\
---------------------------------------------------------------------------

    \38\ For more details of the 2019 base year emissions inventory, 
see 88 FR 1454, January 10, 2023, at p. 1460.
---------------------------------------------------------------------------

    Alaska stated that NOX and SO2 emissions in 
the Fairbanks Revised 189(d) Plan are 17 and nine percent higher 
respectively than in the initial Fairbanks 189(d) Plan. Alaska asserted 
that these emissions increases are largely driven by changes in the 
Point (and Other Area) source emissions, since the new 74-day 2019-2020 
modeling episode was based on actual emissions. In addition, the 
increases in NOX and SO2 emissions for the Other 
Area source sector under the Fairbanks Revised 189(d) Plan are due to 
moving stationary source emissions from Eielson AFB to this sector. 
Under the previous base year emissions inventories, stationary source 
emissions from Eielson were contained in the Point source portion of 
the inventory.
    The reductions in VOC emissions in the Fairbanks Revised 189(d) 
Plan are due to mobile source sector reductions in the MOVES3 model. 
The initial Fairbanks 189(d) Plan inventory was based on an earlier 
version of MOVES that reflected higher VOC emission factors. In 
addition, Alaska stated that VOC reductions in the Space Heating sector 
are likely the result of differences in the mix of wood use by device 
between the two inventories. The Fairbanks Revised 189(d) Plan 
inventory reflects higher usage fractions of certified and pellet-based 
wood burning devices based on data from new 2023 Home Heating survey, 
and these devices have lower VOC emission factors.
    Finally, Alaska noted that the difference in overall NH3 
emissions between the two base year inventories is very modest (one 
percent lower under

[[Page 1605]]

the Fairbanks Revised 189(d) base year emissions inventory). These 
source sector-specific variations mirror the adjustments made to 
PM2.5, SO2, NOX, and VOC emissions 
discussed earlier in this section II.A of this preamble.
    Building from Alaska's new 2020 base year emissions inventory, 
Alaska developed its attainment projections. As a first step, Alaska 
constructed a 2027 baseline emissions inventory that reflected 
projected activity growth factors, previously implemented control 
measures, and other adjustments to point sources and wood usage.\39\
---------------------------------------------------------------------------

    \39\ State Air Quality Control Plan, Vol. II, section III.D.7.6, 
Table 7.6-11.
---------------------------------------------------------------------------

    As a second step, Alaska developed the 2027 projected attainment 
emissions inventory by adjusting the 2027 baseline inventory to account 
for projected emissions reductions from the control strategy included 
in the Fairbanks Revised 189(d) Plan. For a complete list of measures 
included in Alaska's control strategy, see Table 4 in section II.D of 
this preamble below. Notably, as part of the control strategy, the Wood 
Stove Change Out Program and the Oil-To-Gas Conversion Program are 
managed by the local Fairbanks North Star Borough. Direct 
PM2.5 reductions from these programs in 2020 through 2026 
totaled over 1.3 tons per episode day. The State of Alaska manages the 
Solid Fuel-Burning Appliance Curtailment Program as well as seven other 
control measures for which emissions benefits were quantified and 
incorporated into the 2027 attainment projected inventory. Notably, the 
State recently increased the stringency of the curtailment program by 
lowering the alert stages to 20 [mu]g/m\3\ and 30 [mu]g/m\3\, 
respectively. Alaska also utilized funding from the 2019-2020 Targeted 
Airshed Grant (TAG) to purchase three dynamic message highway signs and 
an infrared camera and to expand staffing to increase compliance. For 
details of these projected emissions reductions, see the spreadsheet 
calculations in the State Air Quality Control Plan, Vol. III, Appendix 
III.D.7.6.
    Alaska concluded that, after considering the emissions reductions 
from these control measures, the Fairbanks PM2.5 
Nonattainment Area could demonstrate attainment by 2027, based on the 
2027 attainment year emissions inventory, as summarized in Table 3 of 
this preamble.

        Table 3--2027 Projected Attainment Emissions Inventory, Average Daily Emissions by Source Sector
----------------------------------------------------------------------------------------------------------------
                                                            2027 Projected attainment emissions inventory (tons/
                                                                                    day)
                      Source sector                       ------------------------------------------------------
                                                             PM2.5       NOX        SO2        VOC        NH3
----------------------------------------------------------------------------------------------------------------
Point Sources............................................       0.62      14.60       7.15       0.04      0.095
Area, Space Heating......................................       0.74       2.34       1.98       8.01      0.124
Area, Space Heat, Wood...................................       0.70       0.28       0.04       7.90      0.081
Area, Space Heat, Oil....................................       0.02       1.83       1.91       0.10      0.004
Area, Space Heat, Coal...................................       0.00       0.00       0.00       0.00       0.00
Area, Space Heat, Other..................................       0.02       0.22       0.02       0.01      0.039
Area, Other..............................................       0.13       0.40       0.03       2.33      0.051
Mobile, On-Road..........................................       0.05       0.65       0.00       1.08      0.038
Mobile, Aircraft.........................................       0.12       0.45       5.70       0.17      0.000
Mobile, Nonroad excluding aircraft.......................       0.08       0.32       0.00       2.22      0.002
                                                          ------------------------------------------------------
    Totals...............................................       1.74      18.75      14.86      13.85      0.310
----------------------------------------------------------------------------------------------------------------
Source: State Air Quality Control Plan, Vol. II, section III.D.7.6, Table 7.6-19.

    Alaska observed that the 2027 projected attainment emissions 
inventory provides reductions in total PM2.5 and 
SO2 emissions within the nonattainment area of 41 percent 
and five percent respectively. Within the space heating sector, which 
has a proportionally higher impact on ambient PM2.5, Alaska 
noted that the 2027 projected attainment emissions inventory reductions 
were 63 percent and 45 percent for direct PM2.5 and 
SO2, respectively.
4. EPA Evaluation and Proposed Action Regarding the Emissions Inventory
a. 2020 Base Year Emissions Inventory
    The EPA proposes to approve the 2020 base year emissions inventory 
as meeting the requirements of CAA section 172(c)(3) and 40 CFR 
51.1008. The EPA is proposing to determine that Alaska has justified 
that 2020 is a technically appropriate inventory year consistent with 
40 CFR 51.1008(c)(1). The base year emissions inventory includes actual 
emissions of all sources within the nonattainment area. The EPA 
proposes to determine that a seasonal episode daily average inventory 
is appropriate for the Fairbanks PM2.5 Nonattainment Area 
because the area experiences episodic elevated concentrations of 
PM2.5 during wintertime cold weather events. The emissions 
inventory includes direct PM2.5 emissions, separately 
reported as filterable and condensable emissions, as well as all 
scientific PM2.5 precursors (SO2, NOX, 
VOC, and NH3). Alaska reported emissions for point sources 
according to the point source emissions thresholds of the Air Emissions 
Reporting Rule in 40 CFR part 51, subpart A. Finally, the emissions 
inventory is consistent with the detail and data elements required by 
40 CFR part 51, subpart A. For the EPA's full evaluation, see the EPA's 
technical evaluation of Alaska's emissions inventory included in the 
docket for this action.\40\
---------------------------------------------------------------------------

    \40\ Kotchenruther, Robert. (November 21, 2024). Technical 
support document for Alaska Department of Environmental 
Conservation's amendments to: State Air Quality Control Plan, 
Emission Inventory Data (version August 19, 2024). U.S. 
Environmental Protection Agency, Region 10, Laboratory Services and 
Applied Science Division, EPA-R10-OAR-2024-0595.
---------------------------------------------------------------------------

b. 2027 Projected Attainment Emissions Inventory
    The EPA proposes to approve the 2027 projected attainment emissions 
inventory as meeting the requirements of CAA section 172(c)(3) and 40 
CFR 51.1008. The EPA is proposing to determine that 2027 is the most 
expeditious year for which projected emissions show modeled 
PM2.5 concentrations below the level of the NAAQS. As 
discussed in section II.D of this preamble, Alaska included a model 
output for 2026 that resulted in emissions levels exceeding the 2006 
24-

[[Page 1606]]

hour PM2.5 NAAQS. The attainment projected inventory 
includes the sources in the base year emissions inventory and accounts 
for growth and contraction from both controls and other causes. 
Consistent with the base year emissions inventory, the attainment 
projected emissions inventory is based on episode average daily 
emissions. The attainment projected emissions inventory includes direct 
PM2.5 emissions, separately reported as filterable and 
condensable emissions, as well as all scientific precursors. The 
attainment projected emissions inventory includes the same level of 
emissions detail for the same point sources and for mobile sources 
reported in the base year emissions inventory. For the EPA's full 
evaluation, see the EPA's technical evaluation of Alaska's emissions 
inventory, included in the docket for this action.\41\
---------------------------------------------------------------------------

    \41\ Kotchenruther, Robert. (November 21, 2024). Technical 
support document for Alaska Department of Environmental 
Conservation's amendments to: State Air Quality Control Plan, 
Emission Inventory Data (version August 19, 2024). U.S. 
Environmental Protection Agency, Region 10, Laboratory Services and 
Applied Science Division, EPA-R10-OAR-2024-0595.
---------------------------------------------------------------------------

B. Pollutants Addressed

1. Statutory and Regulatory Requirements Regarding the Pollutants 
Addressed
    Under subpart 4 of part D, title I of the CAA and the 
PM2.5 SIP Requirements Rule, each state containing a 
PM2.5 nonattainment area must evaluate all PM2.5 
precursors for regulation unless, for any given PM2.5 
precursor, the state demonstrates to the Administrator's satisfaction 
that such precursor does not contribute significantly to 
PM2.5 levels that exceed the NAAQS in the nonattainment 
area.\42\ The provisions of subpart 4 do not define the term 
``precursor'' for purposes of PM2.5, nor do they explicitly 
require the control of any specifically identified PM2.5 
precursor. The statutory definition of ``air pollutant,'' however, 
provides that the term ``includes any precursors to the formation of 
any air pollutant, to the extent the Administrator has identified such 
precursor or precursors for the particular purpose for which the term 
`air pollutant' is used.'' \43\ The EPA has identified SO2, 
NOX, VOCs, and NH3 as precursors to the formation 
of PM2.5.\44\ Accordingly, the attainment plan requirements 
of part D, title I of the CAA and the PM2.5 SIP Requirements 
Rule apply to emissions of all four precursors and direct 
PM2.5 from all types of stationary, area, and mobile 
sources, except as otherwise provided in CAA section 189(e).,
---------------------------------------------------------------------------

    \42\ 40 CFR 51.1006, 51.1010; See 81 FR 58010, August 24, 2016, 
at pp. 58017-58020.
    \43\ CAA section 302(g).
    \44\ 81 FR 58010, August 24, 2016, at p. 58015.
---------------------------------------------------------------------------

    As noted in the EPA's Final Policy Assessment for the 
reconsideration of the PM2.5 NAAQS, secondary particulate 
matter is formed in the atmosphere by photochemical oxidation reactions 
of both inorganic and organic gas-phase precursors. Precursor gases 
include SO2, NOX, NH3, and VOC gases 
of anthropogenic or natural origin. Anthropogenic SO2 and 
NOX are the predominant precursor gases in the formation of 
secondary PM2.5 sulfate and nitrate, and NH3 is 
the gas-phase precursor for PM2.5 ammonium. PM2.5 
ammonium formation is enhanced by particle acidity resulting from 
sulfuric acid and nitric acid condensation onto particles. Atmospheric 
oxidation of VOCs, both anthropogenic and biogenic, is an important 
source of organic aerosols, particularly in summer. The semi-volatile 
and nonvolatile products of VOC oxidation reactions can condense onto 
existing particles or can form new particles.\45\
---------------------------------------------------------------------------

    \45\ ``Policy Assessment for the Reconsideration of the National 
Ambient Air Quality Standards for Particulate Matter'' (EPA/452/R-
22-004), EPA, May 2022), p. 2-10.
---------------------------------------------------------------------------

    According to the State, total wintertime PM2.5 
concentrations in the Fairbanks PM2.5 Nonattainment Area are 
a function of both primary PM2.5 emissions and secondary 
PM2.5 formed from precursors (see State Air Quality Control 
Plan, Vol. II, section III.D.7.8.1).
    CAA section 189(e) requires that the control requirements for major 
stationary sources of direct PM10 \46\ and PM2.5 
\47\ also apply to major stationary sources of PM10 and 
PM2.5 precursors, except where the Administrator determines 
that such sources do not contribute significantly to PM10 or 
PM2.5 levels that exceed the standard in the area. CAA 
section 189(e) contains the only express exception to the control 
requirements under subpart 4 (e.g., requirements for reasonably 
available control measures (RACM) and reasonably available control 
technology (RACT), BACM and BACT, Most Stringent Measures (MSM), and 
New Source Review (NSR) for sources of direct PM2.5 and 
PM2.5 precursor emissions). Although CAA section 189(e) 
explicitly addresses only major stationary sources, the EPA interprets 
this provision as authorizing it also to determine, under appropriate 
circumstances, that regulation of specific PM10 or 
PM2.5 precursors from other source categories in a given 
nonattainment area is not necessary.\48\ For example, under the EPA's 
longstanding interpretation of the control requirements that apply to 
stationary, area, and mobile sources of PM10 precursors in 
the nonattainment area under CAA section 172(c)(1) and subpart 4,\49\ a 
state may demonstrate in a SIP submission that control of a certain 
precursor pollutant is not necessary in light of its insignificant 
contribution to ambient PM10 or PM2.5 levels in 
the nonattainment area.\50\
---------------------------------------------------------------------------

    \46\ The requirements for attainment plans for the 2006 24-hour 
PM2.5 NAAQS include the general nonattainment area 
planning requirements in CAA section 172 of title I, part D, subpart 
1 and the additional planning requirements specific to particulate 
matter in CAA sections 188 and 189 of title I, part D, subpart 4. 81 
FR 58010, August 24, 2016, at pp. 58012-58014.
    \47\ The general attainment plan requirements of subpart 1, part 
D, of title I of the CAA in addition to the specific requirements in 
subpart 4, part D, of Title I of the CAA apply to both 
PM10 and PM2.5. See 81 FR 58010, August 24, 
2016, at pp. 58013.
    \48\ 81 FR 58010, August 24, 2016, at pp. 58018-58019.
    \49\ State Implementation Plan; General Preamble for the 
Implementation of Title I of the Clean Air Act Amendments of 1990 
(``General Preamble''), 57 FR 13498, April 16, 1992, at pp. 13539-
42.
    \50\ 40 CFR 51.1006. See also 81 FR 58010, 58033. Courts have 
upheld this approach to the requirements of subpart 4 for 
PM10. See, e.g., Assoc. of Irritated Residents v. EPA, et 
al., 423 F.3d 989 (9th Cir. 2005).
---------------------------------------------------------------------------

    Under the PM2.5 SIP Requirements Rule, a state may elect 
to submit to the EPA a ``comprehensive precursor demonstration'' for a 
specific nonattainment area to show that emissions of a particular 
precursor from all existing sources located in the nonattainment area 
do not contribute significantly to PM2.5 levels that exceed 
the NAAQS at issue in the nonattainment area.\51\ If the EPA determines 
that the contribution of the precursor to PM2.5 levels in 
the area is not significant and approves the demonstration, then the 
state is not required to control emissions of the relevant precursor 
from existing sources in the attainment plan.\52\
---------------------------------------------------------------------------

    \51\ 40 CFR 51.1006(a)(1).
    \52\ 40 CFR 51.1006(a)(1).
---------------------------------------------------------------------------

    Relatedly, under the PM2.5 SIP Requirements Rule, a 
state may submit to the EPA a ``major stationary source precursor 
demonstration'' for a specific nonattainment area that shows that 
emissions of a particular precursor from all existing major stationary 
sources located in the nonattainment area do not contribute 
significantly to PM2.5 levels that exceed the standard in 
the area.\53\ If the EPA approves a major stationary source precursor 
demonstration, then the state is not required to control emissions of 
the relevant precursor from existing major stationary sources in the 
current attainment plan.\54\
---------------------------------------------------------------------------

    \53\ 40 CFR 51.1006(a)(2).
    \54\ 40 CFR 51.1006(a)(2)(iii).

---------------------------------------------------------------------------

[[Page 1607]]

    In addition, in May 2019, the EPA issued the ``PM2.5 
Precursor Demonstration Guidance'' (``PM2.5 Precursor 
Guidance''), which provides recommendations to states for analyzing 
nonattainment area PM2.5 emissions and developing such 
optional precursor demonstrations, consistent with the PM2.5 
SIP Requirements Rule.\55\
---------------------------------------------------------------------------

    \55\ ``PM2.5 Precursor Demonstration Guidance,'' EPA-
454/R-19-004, May 2019, including Memo dated May 30, 2019, from 
Scott Mathias, Acting Director, Air Quality Policy Division and 
Richard Wayland, Director, Air Quality Assessment Division, Office 
of Air Quality Planning and Standards (OAQPS), EPA to Regional Air 
Division Directors, Regions 1-10, EPA.
---------------------------------------------------------------------------

    The EPA evaluated the Fairbanks Revised 189(d) Plan in accordance 
with the presumption embodied within subpart 4 that the State must 
address all PM2.5 precursors in the evaluation and 
implementation of potential control measures, unless the State 
adequately demonstrates that emissions of a particular precursor or 
precursors do not contribute significantly to ambient PM2.5 
levels that exceed the PM2.5 NAAQS in the nonattainment 
area. In reviewing any determination by the state to exclude a 
PM2.5 precursor from the required evaluation of potential 
control measures, we consider both the magnitude of the precursor's 
contribution to ambient PM2.5 concentrations in the 
nonattainment area and the sensitivity of ambient PM2.5 
concentrations in the area to reductions in emissions of that 
precursor.\56\
---------------------------------------------------------------------------

    \56\ 40 CFR 51.1006(a)(1)(i) and (ii).
---------------------------------------------------------------------------

2. Summary of the EPA's Prior Rulemaking Regarding the Pollutants 
Addressed
    On December 5, 2023, the EPA finalized approval of Alaska's 
precursor demonstration that NOX and VOCs are not 
significant precursors to PM2.5 formation in the Fairbanks 
PM2.5 Nonattainment Area.\57\
---------------------------------------------------------------------------

    \57\ 88 FR 84626, December 5, 2023, at p. 84675.
---------------------------------------------------------------------------

3. Summary of the State's Submission Regarding the Pollutants Addressed
    In the Fairbanks Revised 189(d) Plan, in accordance with 40 CFR 
51.1006(a)(2), Alaska included a demonstration that SO2 
emissions from major stationary sources do not significantly contribute 
to PM2.5 formation in the Fairbanks PM2.5 
Nonattainment Area. As discussed in the State Air Quality Control Plan, 
Vol. II, section III.D.7.8.15, Alaska stated that it utilized a new 
model platform that accurately simulated the formation of precursors 
into PM2.5 in the Fairbanks environment. The new model 
platform also demonstrated marked improvement in the simulation of 
sulfate formation from SO2 emissions as compared to prior 
platforms used by Alaska. Using the new model platform, Alaska 
performed a concentration-based contribution analysis using air quality 
modeling with ``zero-out'' model runs. Alaska's analysis showed that 
major stationary sources contributed 0.21 [mu]g/m\3\ PM2.5 
at regulatory monitoring sites in Fairbanks including the North Pole 
monitor (Hurst Road), which is below the 1.5 [mu]g/m\3\ 
PM2.5 threshold included in the EPA's guidance.\58\
---------------------------------------------------------------------------

    \58\ See State Air Quality Control Plan, Vol. II., section 
III.D.7.8.15, Table 7.8.18-1.
---------------------------------------------------------------------------

    According to Alaska, the updated analysis of precursor impacts on 
PM2.5 utilized a photochemical grid model (PGM) that 
accounted for the non-linear secondary effects of precursor gases. PGMs 
account for the atmospheric chemistry, transport, and deposition of 
pollutants using local emissions and meteorological data. The zero-out 
approach compared a baseline model run with a model run where a 
precursor's emissions are set to zero to determine the influence of 
that precursor on PM2.5 formation.
    Alaska noted that a concentration-based analysis was completed that 
excluded all sources of SO2. The monitored filter sulfate 
and the concentrations from the 5-year design value showed total 
sulfate from all sectors was 5.9 [mu]g/m\3\ or 21 percent of the 
PM2.5 at an air quality monitor located in the City of 
Fairbanks (NCore) and 5.9 [mu]g/m\3\ or nine percent of the 
PM2.5 at the North Pole air quality monitor (Hurst Road). 
When accounting for all emissions sources, SO2 remained a 
significant precursor to PM2.5 formation in the Fairbanks 
PM2.5 Nonattainment Area.
    After completing the first step, the major stationary source sector 
SO2 precursor model runs were then performed based on the 
emissions for the 2020 base year and a model run that excluded 
SO2 emissions. The difference in sulfate for a model 
simulation using base year emissions and a second model simulation with 
major stationary-source SO2 emissions set to zero was 
compared with the 1.5 ug/m\3\ threshold. Alaska stated that this 
concentration-based modeling demonstrated the insignificance of 
SO2 from major stationary sources when compared with the 1.5 
[mu]g/m\3\ threshold in the EPA's guidance, and therefore, a 
sensitivity-based contribution analysis was not needed, in accordance 
with 40 CFR 51.1006(a)(2)(ii).
4. The EPA's Evaluation and Proposed Action Regarding the Pollutants 
Addressed
    The EPA evaluated the State's precursor demonstration included in 
the Fairbanks Revised 189(d) Plan. The EPA proposes to determine that 
Alaska's submission meets the requirements of 40 CFR 51.1006(a)(2) and 
is consistent with the EPA guidance.\59\ Regarding the State's 
analytical approach, the EPA proposes to find that the State used 
appropriate methods and data to evaluate PM2.5 formation in 
the Fairbanks PM2.5 Nonattainment Area from precursor 
emissions. Consistent with 40 CFR 51.1006(a)(2), Alaska's submission 
includes a concentration-based contribution analysis. The 
concentration-based analysis shows that the SO2 emissions 
from major stationary sources do not significantly contribute to 
PM2.5 formation in the Fairbanks PM2.5 
Nonattainment Area. Specifically, Alaska's analysis shows that 
SO2 emissions from major stationary sources contribute 0.21 
[mu]g/m\3\ of PM2.5 at the North Pole Hurst Road air quality 
monitor--far below the 1.5 [mu]g/m\3\ threshold included in the EPA 
guidance. For the EPA's full evaluation, see EPA's Technical Support 
Document.\60\ Therefore, the EPA proposes to approve Alaska's precursor 
demonstration submitted as part of the Fairbanks Revised 189(d) Plan as 
demonstrating that the contribution of SO2 from existing 
major stationary sources to PM2.5 levels in the Fairbanks 
PM2.5 Nonattainment Area is not significant in accordance 
with 40 CFR 51.1006(a)(2)(i). If the EPA finalizes approval as 
proposed, Alaska will not be required to control SO2 
emissions from existing major stationary sources in the Fairbanks 
PM2.5 Nonattainment Area, pursuant to CAA section 189 and 40 
CFR 51.1010. For purposes of the Fairbanks Revised 189(d) Plan, the 
PM2.5 plan precursors are: NH3 and SO2 
for all sources except for major stationary sources.
---------------------------------------------------------------------------

    \59\ ``PM2.5 Precursor Demonstration Guidance,'' EPA-
454/R-19-004, May 2019, including Memo dated May 30, 2019, from 
Scott Mathias, Acting Director, Air Quality Policy Division and 
Richard Wayland, Director, Air Quality Assessment Division, Office 
of Air Quality Planning and Standards (OAQPS), EPA to Regional Air 
Division Directors, Regions 1-10, EPA.
    \60\ Briggs, Nicole. (December 2, 2024). Review of Attainment 
Demonstration Modeling and SO2 Precursor Demonstration in the 2024 
State Implementation Plan Submission for the Fairbanks 24-hour PM2.5 
Nonattainment Area. U.S. Environmental Protection Agency, Region 10, 
Laboratory Services and Applied Science Division, EPA-R10-OAR-2024-
0595.
---------------------------------------------------------------------------

    Consistent with its past actions, if finalized, the EPA's approval 
of Alaska's

[[Page 1608]]

precursor demonstration would not extend to nonattainment NSR 
requirements for the area. Alaska previously determined that it was 
appropriate to regulate NOX, SO2, VOCs, and 
NH3 as precursors to PM2.5 with respect to 
nonattainment NSR and submitted rule changes to that effect on October 
25, 2018. The EPA approved the submitted revised program as meeting 
nonattainment NSR requirements triggered upon reclassification of the 
Fairbanks PM2.5 Nonattainment Area to Serious (84 FR 45419, 
August 29, 2019).

C. Control Strategy

1. Statutory and Regulatory Requirements Regarding the Control Strategy
    CAA section 189(b) and 40 CFR 51.1010(a) contain the control 
measure requirements for Serious areas. CAA section 189(d) and 40 CFR 
51.1010(c) contain the control measure requirements for Serious areas 
that fail to attain.
    Pursuant to CAA section 189(b) and 40 CFR 51.1010(a), the state 
must identify, adopt, and implement best available control measures, 
including best available control technologies, on sources of direct 
PM2.5 emissions and sources of emissions of PM2.5 
plan precursors located in any Serious PM2.5 nonattainment 
area or portion thereof located within the state. This level of control 
stringency is commonly called ``BACM'' and ``BACT.'' The regulation at 
40 CFR 51.1010(a) specifies the requirements states must meet to 
identify potential control measures and in determining the measures 
states must include in the control strategy as BACM or BACT for the 
nonattainment area:
    The state must identify all sources of direct PM2.5 
emissions and sources of emissions of PM2.5 precursors in 
the nonattainment area, in accordance with the emissions inventory 
requirements in 40 CFR 51.1008(b).
    The state must identify all potential control measures to reduce 
emissions from all sources of direct PM2.5 emissions and 
sources of emissions of PM2.5 plan precursors in the 
nonattainment area. The state must survey other NAAQS nonattainment 
areas in the U.S. and identify any measures for direct PM2.5 
and PM2.5 plan precursors not previously identified by the 
state during the development of the Moderate area or Serious area 
attainment plan for the area.
    The state must identify, adopt, and implement the best available 
control measures for each emission source. However, the state may 
demonstrate that any measure identified under 40 CFR 51.1010(a)(2) is 
not technologically or economically feasible to implement in whole or 
in part by the end of the tenth calendar year following the effective 
date of designation of the area and may eliminate such whole or partial 
measure from further consideration. Overall, economic feasibility is a 
less significant factor in the BACM and BACT determination process.\61\ 
There are considerations for technological feasibility of a potential 
control measure, where a state may consider factors including but not 
limited to a source's processes and operating procedures, raw 
materials, physical plant layout, and potential environmental impacts 
such as increased water pollution, waste disposal, and energy 
requirements.\62\ There are also considerations for economic 
feasibility of a potential control measure where a state may consider 
capital costs, operating and maintenance costs, and cost effectiveness 
of the measure.\63\ In assessing whether a control measure or 
technology is BACM or BACT, the state must consider emissions reduction 
measures with higher costs per ton compared to the economic feasibility 
criteria applied in their RACM or RACT analysis.\64\ With respect to 
determining BACT pursuant to CAA section 189(b), the EPA expects that 
states use the top-down BACT analysis process used in the Prevention of 
Significant Deterioration (PSD) Program.\65\
---------------------------------------------------------------------------

    \61\ Id.
    \62\ 40 CFR 51.1010(a)(3)(i); 81 FR 58010, August 24, 2016, at 
p. 58084.
    \63\ 40 CFR 51.1010(a)(3)(ii); 81 FR 58010, August 24, 2016, at 
p. 58085.
    \64\ 81 FR 58010, August 24, 2016, at p. 58085.
    \65\ Id. at p. 58080 (``Consistent with past policy, BACT 
determinations for PM2.5 NAAQS implementation are to 
follow the same process and criteria that are applied to the BACT 
determination process for the PSD program.'').
---------------------------------------------------------------------------

    Pursuant to CAA section 189(b), a state with a Serious 
nonattainment area must include provisions to assure the implementation 
of BACM and BACT-level controls on sources of direct PM2.5 
and PM2.5 plan precursors no later than 4 years after the 
date the area is classified (or reclassified) as a Serious area.
    In the preamble to the final PM2.5 SIP Requirements 
Rule, the EPA recommended the following the 5-Step BACM/BACT selection 
process that states should follow to satisfy the analytical and 
substantive requirements of 40 CFR 51.1010(a) and CAA section 189(b): 
\66\
---------------------------------------------------------------------------

    \66\ Id. at pp. 58084-85.
---------------------------------------------------------------------------

    Step 1: Develop a comprehensive inventory of sources and source 
categories of directly emitted PM2.5 and PM2.5 
precursors.
    Step 2: Identify potential control measures for all such sources.
    Step 3: Determine whether an available control measure or 
technology is technologically feasible.
    Step 4: Determine whether an available control measure or 
technology is economically feasible.
    Step 5: Determine the earliest date by which a control measure or 
technology can be implemented in whole or in part in the area.
    The EPA interprets CAA section 189(b) to require the state to 
determine what is BACM or BACT for a particular source or source 
category.\67\ The EPA's longstanding interpretation of the CAA is that 
BACM and BACT determinations are to be generally independent of 
attainment for purposes of implementing the PM2.5 NAAQS.\68\ 
The EPA interprets the CAA requirement to impose BACM/BACT level 
control as requiring more emphasis on what controls are the best for 
the relevant source and whether those controls are feasible rather than 
on the attainment needs of the area.\69\ States also may not decline to 
evaluate, or to control as necessary, sources or source categories on 
the basis that they are de minimis.\70\
---------------------------------------------------------------------------

    \67\ Id. at p. 58081.
    \68\ State Implementation Plans for Serious PM-10 Nonattainment 
Areas, and Attainment Date Waivers for PM-10 Nonattainment Areas 
Generally; Addendum to the General Preamble for the Implementation 
of Title I of the Clean Air Act Amendments of 1990 (``Addendum to 
the General Preamble''), 59 FR 41998, at p. 42011 (August 16, 1994); 
81 FR 58010, August 24, 2016, at p. 58081.
    \69\ Id.
    \70\ Id. at p. 58082.
---------------------------------------------------------------------------

    Subsequently, for a state with a Serious PM2.5 
nonattainment area that has failed to attain by the applicable 
attainment date, the state must submit a revised attainment plan with a 
control strategy that demonstrates that each year the area will achieve 
at least a five percent reduction in emissions of direct 
PM2.5 or a five percent reduction in emissions of a 
PM2.5 plan precursor based on the most recent emissions 
inventory for the area; and that the area will attain the standard as 
expeditiously as practicable consistent with the attainment date 
requirements under 40 CFR 51.1004(a)(3).\71\ The regulation at 40 CFR 
51.1010(c) specifies the following process the state must follow in 
determining which measures must be included in the control strategy:
---------------------------------------------------------------------------

    \71\ CAA section 189(d), 42 U.S.C. 7513a(d), and 40 CFR 
51.1010(c).
---------------------------------------------------------------------------

    The state shall identify all sources of direct PM2.5 
emissions and sources of

[[Page 1609]]

emissions of PM2.5 precursors in the nonattainment area in 
accordance with the emissions inventory requirements in 40 CFR 
51.1008(b).
    The state shall identify all potential control measures to reduce 
emissions from all sources of direct PM2.5 emissions and 
sources of emissions of PM2.5 plan precursors in the 
nonattainment area. For the sources and source categories represented 
in the emissions inventory for the nonattainment area, the state shall 
identify the most stringent measures (MSM) for reducing direct 
PM2.5 and PM2.5 plan precursors adopted into any 
SIP or used in practice to control emissions in any state, as 
applicable.
    The state shall also reconsider and reassess any measures 
previously rejected by the state during the development of any Moderate 
area or Serious area attainment plan control strategy for the area. 
Similar to the requirements for Serious area plans, the state may make 
a demonstration for a 189(d) plan that a measure is not technologically 
or economically feasible to implement in whole or in part within 5 
years or such longer period as the EPA may determine is appropriate 
after the EPA's determination that the area failed to attain by the 
Serious area attainment date and may eliminate such whole or partial 
measure from further consideration. There are considerations for 
technological feasibility of a potential control measure, as described 
under 40 CFR 51.1010(c)(3)(i), where a state may consider factors 
including but not limited to a source's processes and operating 
procedures, raw materials, physical plant layout, and potential 
environmental impacts such as increased water pollution, waste 
disposal, and energy requirements. There are also considerations for 
economic feasibility of a potential control measure, under 40 CFR 
51.1010(c)(3)(ii), where a state may consider capital costs, operating 
and maintenance costs, and cost effectiveness of the measure. Unless 
the state has demonstrated that the measure is not technologically or 
economically feasible, the state shall adopt and implement all 
potential control measures identified.
    Finally, control measures adopted as part of the state's control 
strategy must be permanent, enforceable as a practical matter, and 
quantifiable.\72\ In order to be enforceable as a practical matter, the 
state must adopt into the SIP not only the control measure or emissions 
limit itself but also appropriate monitoring, recordkeeping, and 
reporting requirements to ensure compliance with the control 
measure.\73\ Without appropriate monitoring, recordkeeping, and 
reporting requirements, violations of the control measure could go 
undetected.\74\
---------------------------------------------------------------------------

    \72\ Control measures must be incorporated by reference into the 
regulatory portion of the SIP (52.70(c) and (d)) with appropriate 
monitoring and reporting requirements. See CAA section 110(a)(2)(A); 
42 U.S.C. 7410(a)(2)(A); 81 FR 58010, August 24, 2016, at pp. 58046-
47; 57 FR 13498, April 16, 1992, at pp.13567-68.
    \73\ 81 FR 58010, August 24, 2016, at pp. 58046-47; 57 FR 13498, 
April 16, 1992, at pp. 13567-68; 67 FR 22168, May 2, 2002, at p. 
22170; 80 FR 33840, June 12, 2015, at pp. 33843, 33865; Montana 
Sulphur & Chemical Co. v. EPA, 666 F.3d 1174, at pp. 1189-1190 (9th 
Cir. 2012).
    \74\ 67 FR 22168, May 2, 2022, at p. 22170; Montana Sulphur & 
Chemical Co. v. EPA, 666 F.3d 1174, at pp. 1189-1190 (9th Cir. 
2012).
---------------------------------------------------------------------------

2. Summary of the EPA's Prior Rulemaking Regarding the Control Strategy
    On December 5, 2023, the EPA finalized an approval in part and 
disapproval in part of the BACM requirements for the Fairbanks 
PM2.5 Nonattainment Area. The EPA's action for each 
emissions source category is described in the following paragraphs.
a. Alaska's Identification and Adoption of BACM for Home Heating and 
Other Area Sources
i. Solid Fuel-Burning
    The EPA approved in part and disapproved in part Alaska's analysis 
and adoption of control measures for this source category as meeting 
the BACM requirements for PM2.5 and SO2 
emissions.\75\ The EPA approved Alaska's analysis that found no 
NH3-specific emissions controls for this source category. 
The EPA also previously approved as SIP strengthening and federally 
enforceable many of the control measures submitted as part of the 
Fairbanks Serious Plan and prior SIP submissions in 2018 as part of a 
separate action (86 FR 52997, September 24, 2021).
---------------------------------------------------------------------------

    \75\ 88 FR 84626, December 5, 2023, at p. 84674.
---------------------------------------------------------------------------

    Alaska identified a number of solid fuel-burning control measures 
that have been adopted by other states and local authorities to 
identify the full range of potential BACM/BACT measures for this source 
category. This analysis took into account technical and economic 
feasibility and other considerations included in the PM2.5 
SIP Requirements Rule.
    Alaska's two-stage Solid Fuel-Burning Appliance Curtailment 
Program, included in the Fairbanks Emergency Episode Plan, adopts air 
quality thresholds that are at least as stringent as comparable 
curtailment programs in Idaho, Utah, and California. Alaska accounted 
for the differences in natural gas availability, seasonal climate 
conditions, and wood stove change-out incentives in establishing the 
two-stage thresholds at 20 [micro]g/m\3\ (Stage 1) and 30 [micro]g/m\3\ 
(Stage 2), respectively. Alaska also had an advisory level set at 15 
[micro]g/m\3\ as part of the curtailment program. Alaska placed further 
limitations on the ``No Other Adequate Source of Heat'' (NOASH) waiver 
(available to households as a temporary waiver from certain curtailment 
requirements), limiting applicability to those that have economic needs 
based on objective criteria and limiting the number of years NOASH 
waivers are available. Therefore, the EPA approved the Solid Fuel-
Burning Appliance Curtailment Program and associated updates to the 
NOASH waivers and temporary exemption as BACM for the solid-fuel 
burning source category (i.e., Alaska state regulations 18 AAC 50.075 
(e)(3), (f)(2)) for PM2.5 and SO2 emissions.\76\
---------------------------------------------------------------------------

    \76\ 88 FR 84626, December 5, 2023, at pp. 84699, 84673-84675.
---------------------------------------------------------------------------

    Alaska identified and evaluated as BACM the heating device 
performance standards adopted previously by Missoula County, Montana. 
Alaska adopted a regulation modeled after the rule in Missoula County. 
Under 18 AAC 50.077(c), Alaska's regulations require that wood stoves 
meet emissions standards that are more stringent than the EPA's New 
Source Performance Standards (NSPS) requirement for residential wood 
heaters at 40 CFR part 60 and also include one-hour testing 
requirements to ensure only the lowest-emitting wood stoves are allowed 
to be sold and installed in the nonattainment area. The EPA approved 
these measures as BACM for the solid-fuel burning source category 
(i.e., 18 AAC 50.077 (a-j)) for PM2.5 and SO2 
emissions.\77\
---------------------------------------------------------------------------

    \77\ Id.
---------------------------------------------------------------------------

    Alaska's regulation 18 AAC 50.075(f), applicable to the Fairbanks 
PM2.5 Nonattainment Area, prohibits the operation of a solid 
fuel-fired heating device emissions when visible emissions exceed 20 
percent opacity for more than six minutes in any one hour, except 
during the first 15 minutes after initial firing of the device, when 
the opacity limit must be less than 50 percent. The rule also prohibits 
visible emissions from crossing property lines. These opacity limits 
provide a visual indicator for the proper operation of a solid-fuel 
heating device. The EPA approved this measure as BACM.\78\
---------------------------------------------------------------------------

    \78\ Id.
---------------------------------------------------------------------------

    The EPA approved as BACM the additional removal or render 
inoperable

[[Page 1610]]

restrictions placed on non-certified EPA wood stoves, non-pellet 
outdoor hydronic heaters, coal-fired heating devices, and EPA-certified 
wood stoves greater than 25 years-old meet BACM requirements for 
PM2.5 and SO2 emissions.\79\ These devices are to 
be removed or rendered inoperable by December 31, 2024, or if a 
building or residence with such a device is sold prior to that date (or 
if a wood-fired heating device is 25 years old prior to that date). 
These include Alaska state regulations 18 AAC 50.077 (l-m). The EPA 
approved the other solid-fuel burning regulations adopted by Alaska, 
including device registration under 18 AAC 50.077(h) and dry wood 
requirements for wood sellers 18 AAC 50.076, which are at least as 
stringent as similar regulations adopted by other states and local 
authorities, and therefore represent BACM for PM2.5 and 
SO2 emissions for the solid-fuel burning source 
category.\80\ These include Alaska state regulations 18 AAC 50.076 (d-
e), (g), (j-l).
---------------------------------------------------------------------------

    \79\ Id.
    \80\ Id.
---------------------------------------------------------------------------

    However, the EPA partially disapproved as BACM Alaska's measures 
regarding dry wood seller requirements and coal-fired heating 
devices.\81\ The EPA recommended Alaska revise 18 AAC 50.076(k)(3) to 
require a specific frequency wood sellers are required to measure the 
moisture content of the seller's wood stock. Likewise, the EPA also 
recommended Alaska revise the regulations at 18 AAC 50.079(d), (e) and 
(f) to remove (or revise to BACM and BACT-level stringency) the testing 
exemption in (d), remove or properly bound the waiver provision in (e), 
and add requirements to verify compliance with the requirement for the 
owner and operator to render the device inoperative.
---------------------------------------------------------------------------

    \81\ 88 FR 84626, December 5, 2023, at pp. 84670, 84675-76.
---------------------------------------------------------------------------

ii. Residential and Commercial Fuel Oil Combustion
    Alaska adopted the regulation at 18 AAC 50.078(b) that imposed a 
limit of 1,000 parts per million sulfur (diesel no. 1) for residential 
and commercial heating. This was a switch from diesel no. 2 
(approximately 2,000 parts per million sulfur) to diesel no. 1. Alaska 
also evaluated the potential for adopting ULSD for fuel oil combustion, 
but the State determined that this measure is economically infeasible. 
The EPA approved 18 AAC 50.078(b) as meeting the SO2 BACM 
and BACT requirements for the space heating area source category.\82\
---------------------------------------------------------------------------

    \82\ 88 FR 84626, December 5, 2023, at p. 84674-75.
---------------------------------------------------------------------------

iii. Small Commercial Area Sources
    The EPA approved Alaska's determination that there were no 
incinerators in the nonattainment area. Therefore, Alaska need not 
identify, adopt, or implement controls for the incinerator source 
category. The EPA also approved Alaska's BACM infeasibility 
demonstrations for add-on control for charbroilers and restrictions on 
used oil burners. By extension, the EPA approved 18 AAC 50.055 as BACM/
BACT for the charbroiler source category.\83\
---------------------------------------------------------------------------

    \83\ Id.
---------------------------------------------------------------------------

    However, the EPA disapproved Alaska's BACM requirements for coffee 
roasters. The EPA cited a number of deficiencies with Alaska's adopted 
control measure for coffee roasters at 18 AAC 50.078(d).\84\
---------------------------------------------------------------------------

    \84\ 88 FR 84626, December 5, 2023, at p. 84676; See also 81 FR 
58010, August 24, 2016, at p. 58047.
---------------------------------------------------------------------------

iv. Weatherization and Energy Efficiency
    The EPA disapproved Alaska's BACM analysis with respect to 
potential energy efficiency and weatherization measures. The State 
provided a number of reasons for declining to adopt and implement any 
such measures, each of which the EPA rejected as bases to not adopt 
weatherization and energy efficiency measures.\85\
---------------------------------------------------------------------------

    \85\ 88 FR 84626, December 5, 2023, at pp. 84641, 84676; See 
also 81 FR 58010, August 24, 2016, at p. p. 58085.
---------------------------------------------------------------------------

v. Emissions From Mobile Sources
    The EPA approved Alaska's rejection of the CARB vehicle standards 
as economically infeasible. The EPA likewise finalized approval of 
Alaska's rejection of school bus retrofits, road paving, and controls 
on road sanding and salting as technologically infeasible. The EPA 
approved Alaska's rejection of a motor vehicle inspection and 
maintenance (I/M) program. The EPA approved Alaska's determination that 
no NH3-specific emissions controls exist for this source 
category.\86\
---------------------------------------------------------------------------

    \86\ 88 FR 84626, December 5, 2023, at p 84675-76.
---------------------------------------------------------------------------

    The EPA approved Alaska's rejection of other transportation 
measures as either technologically infeasible (HOV lanes) or 
economically infeasible (traffic flow improvements, diesel retrofit 
projects, and ridesharing programs).\87\
---------------------------------------------------------------------------

    \87\ Id.
---------------------------------------------------------------------------

    However, the EPA approved in part and disapproved in part Alaska's 
rejection of vehicle idling restrictions and other transportation 
measures.\88\ Specifically, the EPA approved Alaska's rejection of 
vehicle idling restrictions for heavy-duty diesel vehicles as 
economically infeasible. However, the EPA disapproved Alaska's 
rejection of vehicle idling restrictions for light-duty vehicles at 
schools and commercial establishments. The EPA determined that Alaska 
had not demonstrated that vehicle anti-idling restrictions for light-
duty passenger vehicles are infeasible.
---------------------------------------------------------------------------

    \88\ Id.
---------------------------------------------------------------------------

b. Alaska's Identification and Adoption of BACT for Major Stationary 
Sources
    In its December 5, 2023, action, the EPA partially approved and 
partially disapproved the Fairbanks Serious Plan as meeting the BACM 
and BACT requirements for major stationary sources.
i. Chena Power Plant
    The EPA partially approved and partially disapproved Alaska's BACM/
BACT evaluation for the Chena Power Plant. The EPA partially 
disapproved the BACT determination because Alaska did not identify, 
adopt, and implement BACT for PM2.5 and SO2. The 
EPA approved Alaska's BACT analysis for NH3 emissions 
controls for the Chena Power Plant.\89\
---------------------------------------------------------------------------

    \89\ 88 FR 84626, December 5, 2023, at pp. 84670-71, 84675-76.
---------------------------------------------------------------------------

ii. Doyon-Fort Wainwright Central Heating and Power Plant
    The EPA partially approved and partially disapproved Alaska's BACM/
BACT determinations for PM2.5 controls for each of the 
emission sources at Doyon-Fort Wainwright Central Heating and Power 
Plant. The EPA partially approved the BACT determinations because 
Alaska's BACT findings for PM2.5 (embodied in State Air 
Quality Control Plan, Vol. II, section III.D.7.7, Tables 7.7-11 and 
7.7-13 and section III.D.7.7.8.3.4) were consistent with CAA section 
189(b) and 40 CFR 51.1010(a). The EPA partially disapproved the BACT 
determinations because the Fairbanks Serious Plan and initial Fairbanks 
189(d) Plan lacked provisions necessary to ensure the BACT 
determinations for PM2.5 are enforceable as a practical 
matter as required by CAA sections 110(a)(2)(A) and 172(c)(7).\90\
---------------------------------------------------------------------------

    \90\ Id.
---------------------------------------------------------------------------

    On September 25, 2023, Alaska withdrew its SO2 BACT 
determinations for Doyon-Fort Wainwright Central Heating and Power 
Plant. Therefore, the EPA finalized disapproval of Alaska's 
SO2 BACT determinations because the

[[Page 1611]]

Fairbanks Serious Plan and initial Fairbanks 189(d) Plan did not 
identify, adopt, and implement BACT for SO2 at the Doyon-
Fort Wainwright Central Heating and Power Plant. The EPA approved 
Alaska's analysis that found no NH3-specific emissions 
controls for the sources at this facility.\91\
---------------------------------------------------------------------------

    \91\ Id.
---------------------------------------------------------------------------

iii. University of Alaska Fairbanks Campus Power Plant
    The EPA disapproved Alaska's BACM/BACT determination for 
PM2.5 controls for the Small Diesel-Fired Engines (EU IDs 
23, 26, and 27). The EPA partially approved and partially disapproved 
the Alaska's BACT determinations for PM2.5 controls for the 
remaining emission units. The EPA partially approved the 
PM2.5 BACT determinations because Alaska's BACT 
determinations embodied in State Air Quality Control Plan, Vol. II, 
section III.D.7.7, Table 7.7-16 and section III.D.7.7.8.6 were 
consistent with CAA section 189(b) and 40 CFR 51.1010(a). The EPA 
partially disapproved Alaska's BACT determinations because the 
Fairbanks Serious Plan and initial Fairbanks 189(d) Plan lacked 
provisions necessary to ensure the BACT determinations are enforceable 
as a practical matter as required by CAA sections 110(a)(2)(A) and 
172(c)(7).\92\
---------------------------------------------------------------------------

    \92\ Id. at p. 84657
---------------------------------------------------------------------------

    On September 25, 2023, Alaska withdrew its SO2 BACT 
determinations for the Fairbanks Campus Power Plant. Therefore, the EPA 
disapproved Alaska's SO2 BACT determinations because the 
Fairbanks Serious Plan and initial Fairbanks 189(d) Plan did not 
identify, adopt, and implement BACT for SO2 at the Fairbanks 
Campus Power Plant. The EPA approved Alaska's analysis that found no 
NH3-specific emissions controls for the sources at this 
facility.\93\
---------------------------------------------------------------------------

    \93\ Id. at pp. 84670-71, 84675-76.
---------------------------------------------------------------------------

iv. Zehnder Power Plant
    The EPA partially approved and partially disapproved Alaska's BACM/
BACT provisions for PM2.5 controls for all emission units at 
the Zehnder Power Plant. The EPA partially approved the 
PM2.5 BACT determination because Alaska's BACT 
determinations embodied in the State Air Quality Control Plan, Vol. II, 
section III.D.7.7, Table 7.7-14 and Appendix III.D.7.7.8.4 are 
consistent with CAA section 189(b) and 40 CFR 51.1010(a). The EPA 
partially disapproved Alaska's PM2.5 BACT determinations 
because the Fairbanks Serious Plan and initial Fairbanks 189(d) Plan 
lacked provisions necessary to ensure the PM2.5 BACT 
determinations are enforceable as a practical matter as required by CAA 
sections 110(a)(2)(A) and 172(c)(7).\94\
---------------------------------------------------------------------------

    \94\ Id.
---------------------------------------------------------------------------

    On September 25, 2023, Alaska withdrew its SO2 BACT 
determinations for the Zehnder Power Plant. Therefore, the EPA 
partially disapproved the SO2 BACT determinations because 
Fairbanks Serious Plan and initial Fairbanks 189(d) Plan did not 
identify, adopt, and implement BACT for SO2 at the Zehnder 
Power Plant. The EPA approved Alaska's analysis that found no 
NH3-specific emissions controls for the sources at this 
facility.\95\
---------------------------------------------------------------------------

    \95\ Id.
---------------------------------------------------------------------------

v. North Pole Power Plant
    The EPA partially approved and partially disapproved Alaska's BACM/
BACT provisions for PM2.5 controls for all emission units at 
the North Pole Power Plant. The EPA partially approved Alaska's 
PM2.5 BACT determinations because these findings embodied in 
State Air Quality Control Plan, Vol. II, section III.D.7.7, Table 7.7-
14 and Appendix III.D.7.7.8.5 are consistent with CAA section 189(b) 
and 40 CFR 51.1010(a). The EPA partially disapproved Alaska's 
PM2.5 BACT determinations because the Fairbanks Serious Plan 
and initial Fairbanks 189(d) Plan lacked provisions necessary to ensure 
the BACT determinations are enforceable as a practical matter as 
required by CAA sections 110(a)(2)(A) and 172(c)(7).\96\
---------------------------------------------------------------------------

    \96\ Id.
---------------------------------------------------------------------------

    On September 25, 2023, Alaska withdrew its SO2 BACT 
determinations for the North Pole Power Plant. Therefore, the EPA 
partially disapproved Alaska's SO2 BACT determinations 
because the Fairbanks Serious Plan and initial Fairbanks 189(d) Plan 
did not identify, adopt, and implement BACT for SO2 at the 
North Pole Power Plant. The EPA approved Alaska's analysis that found 
no NH3-specific emissions controls for the sources at this 
facility.
c. NH3 Emissions Controls
    With respect to NH3 controls, for residential and 
commercial area sources, the EPA approved certain measures as meeting 
the BACM/BACT requirement for NH3 emissions. In other cases, 
the EPA approved Alaska's BACM/BACT analysis that concluded there are 
no NH3-specific controls for the emission source categories 
contributing to PM2.5 formation in the Fairbanks 
PM2.5 Nonattainment Area, but that there are likely to be 
NH3 emissions co-benefits of measures designed to reduce 
emissions of direct PM2.5.\97\
---------------------------------------------------------------------------

    \97\ Id.
---------------------------------------------------------------------------

3. Summary of the State's Submission and the EPA's Evaluation and 
Proposed Action Regarding the Control Strategy
a. Updates to the Identification and Adoption of BACM
    Below is a summary of the regulations and SIP revisions adopted as 
part of the Fairbanks Revised 189(d) Plan, organized by source 
category, responding to EPA's December 5, 2023, disapproval.\98\
---------------------------------------------------------------------------

    \98\ State Air Quality Control Plan, Vol. II, section 
III.D.7.7.13.
---------------------------------------------------------------------------

i. Solid-Fuel Burning
    Alaska revised the dry wood seller measure, adopted as regulation 
18 AAC 50.076(k)(3), by setting a frequency at monthly intervals to 
measure the moisture content. Alaska also revised regulation 18 AAC 
50.076(k)(1) by improving the labeling to indicate ``dry wood.''
    Regarding the EPA's disapproval of coal-fired heating device 
requirements, Alaska revised 18 AAC 50.079 by lowering the emissions 
threshold to test out of the mandatory removal requirements in 18 AAC 
50.079(d) from 18 grams per hour to 0.10 pounds per million British 
thermal units (Btu) which is equivalent to the pellet hydronic heater 
limit in 18 AAC 50.077. Alaska amended 18 AAC 50.079(d) to require a 
testing protocol be approved by the department prior to any test 
attempting to exempt a coal device from the mandatory removal 
requirement. Alaska revised 18 AAC 50.079(e) limit the duration of the 
waiver to one calendar year.
    The EPA previously approved 18 AAC 50.079(f), which requires the 
owner of a coal-fired heating device to render it inoperable not later 
than December 31, 2024. As a consequence of Alaska's revisions to 18 
AAC 50.079(f), the latest an individual with a coal-fired heating 
device could remove that device is December 31, 2025--provided the 
individual meets the eligibility requirements in 18 AAC 50.079(e). 
Alaska stated that 18 AAC 50.079(f) is revised for clarity by adding 
section (3), which requires coal-fired heating devices to be rendered 
inoperable after the expiration of a waiver granted under subsection 
(e) of 18 AAC 50.079. Alaska stated that newly adopted section 18 AAC 
50.079(h) requires documentation on the removal and rendering of the 
device inoperable and submitting an affidavit that the coal stove will 
not be

[[Page 1612]]

reinstalled in the Fairbanks PM2.5 Nonattainment Area.
    Based on these updates, the EPA proposes to approve the submitted 
revisions to 18 AAC 50.076 and 18 AAC 50.079 as meeting the 
requirements of CAA sections 110(a)(2)(A), 172(c)(7), and 189(b) and 40 
CFR 51.1010(a). Accordingly, the EPA proposes to determine that the 
Fairbanks Revised 189(d) Plan rectifies the disapproved portions of the 
Fairbanks Serious Plan and initial Fairbanks 189(d) Plan for the solid 
fuel-burning source category.
ii. Residential and Commercial Fuel Oil Combustion
    In the EPA's December 5, 2023, rule, the EPA approved as BACM 
Alaska's regulation under 18 AAC 50.078(b) that imposes a limit of 
1,000 parts per million sulfur content in fuel limit (diesel no. 1) for 
residential and commercial heating.\99\ This was a switch from diesel 
no. 2 (approximately 2,000 parts per million sulfur content in fuel 
limit) to diesel no. 1. The EPA agreed with Alaska's demonstration that 
further strengthening this requirement to 15 parts per million sulfur 
(i.e., Ultra-low sulfur diesel) was economically infeasible.
---------------------------------------------------------------------------

    \99\ 88 FR 84626, December 5, 2023, at pp. 84669, 84674.
---------------------------------------------------------------------------

iii. Small Commercial Area Sources
    Alaska revised its regulations for coffee roasters, under 18 AAC 
50.078(d). These updated regulations clarify the specific emission 
limit required for this source category and ensures the limit is 
enforceable as a practical matter. The EPA proposes to approve the 
submitted revisions to 18 AAC 50.078(d) as meeting the requirements of 
CAA section 110(a)(2), 172(c)(7), and 189(b) and 40 CFR 51.1010(a) for 
this source category. Accordingly, the EPA proposes to determine that 
the Fairbanks Revised 189(d) Plan rectifies the disapproved portions of 
the Fairbanks Serious Plan and initial Fairbanks 189(d) Plan for coffee 
roasters.
iv. Energy Efficiency and Weatherization
    To address the EPA's disapproval, Alaska reviewed weatherization 
and energy efficiency measures adopted by other jurisdictions. Based on 
this review, Alaska adopted a weatherization and energy efficiency 
measure at 18 AAC 50.081. The measure mandates that a building owner 
have an energy rating completed on the building before listing it for 
sale. The rule requires that the seller provide the energy rating 
report to the buyer. Alaska also committed to a robust advertising and 
education program that includes best practices to improve efficiency in 
an arctic environment and available economic and practical mechanisms 
that can assist homeowners in improving both efficiency and regulatory 
compliance. Alaska asserted that these components will improve the 
compliance rate for other control measures, including the solid fuel-
fired heating device curtailment program and the requirement to remove 
older, uncertified heating appliances. Alaska noted that any 
improvements identified by the energy rater will be voluntary.
    Alaska evaluated adopting building energy efficiency codes or 
mandatory weatherization requirements and dismissed them as 
technologically infeasible. According to Alaska, there is a lack of 
technical expertise and resources to implement (lack of energy auditors 
and training resources), enforce, and ensure code compliance. Alaska 
further contended that the earliest date Alaska can implement building 
codes exceeded not only the statutory requirement for the 
implementation of BACM by December 31, 2024, but also beyond the 2027 
attainment date identified in the Fairbanks Revised 189(d) Plan.
    The EPA proposes to approve the submitted revisions to 18 AAC 
50.081 as meeting the requirements of CAA sections 110(a)(2), 
172(c)(7), and 189(b) and 40 CFR 51.1010(a) with respect to 
weatherization and energy efficiency. Accordingly, the EPA proposes to 
determine that the Fairbanks Revised 189(d) Plan rectifies the 
disapproved portions of the Fairbanks Serious Plan and initial 
Fairbanks 189(d) Plan for weatherization and energy efficiency.
v. Emissions From Mobile Sources
    The EPA previously approved as part of Fairbanks Moderate Plan, a 
requirement that businesses with 275 or more parking spaces provide 
power to electrical outlets at temperatures of 20 degrees Fahrenheit or 
lower for engine block heaters.\100\ In addition, Alaska continues to 
install new plug-ins throughout the Fairbanks PM2.5 
Nonattainment Area.\101\
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    \100\ 82 FR 42457, September 8, 2017; State Air Quality Control 
Plan, Vol. III, Appendix III.D.5.7, adopted December 24, 2014, at p. 
43; State Air Quality Control Plan, Vol. III, Appendix III.D.5.12, 
adopted December 24, 2014, at p. 43.
    \101\ There are nearly 10,000 plug-ins available in the 
nonattainment area. See State Air Quality Control Plan, Appendix 
III.D.7.7 (adopted November 19, 2019), at p. 17.
---------------------------------------------------------------------------

    As part of the Fairbanks Revised 189(d) Plan, Alaska re-evaluated 
anti-idling for light-duty vehicles as a potential control measure. 
Alaska provided additional analysis demonstrating that such a measure 
is technologically and economically infeasible in the Fairbanks 
PM2.5 Nonattainment Area. In particular, Alaska noted that 
other jurisdictions that implement this measure include a temperature 
threshold, below which restrictions do not apply. These temperature cut 
offs range from 40 degrees Fahrenheit to 10 degrees Fahrenheit. These 
thresholds are intended to protect human health and safety.
    Accordingly, Alaska evaluated implementing idling restrictions 
during the winter months of October through March at temperatures above 
21 degrees Fahrenheit. Given that episodic emissions contributing to 
PM2.5 concentrations occur at sub-zero temperatures, 
Alaska's evaluation indicates that the measure would not achieve any 
emissions reductions.
    The EPA notes that in order to achieve emissions reductions in the 
extreme Fairbanks environment, Alaska would have to prohibit idling 
regardless of ambient temperature, which presents unacceptable risks to 
human health. In light of these concerns, rather than regulate the 
vehicle users, Alaska requires owners of parking areas to provide 
electricity for engine-block heaters. Alaska and the EPA have 
previously determined that expanding plug-in availability is 
economically infeasible.\102\ Therefore, the EPA proposes to approve 
Alaska's current plug-in program as meeting BACM and BACT requirements 
for light-duty vehicles.
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    \102\ 88 FR 84626, December 5, 2023, at pp. 84649, 84652 
(determining that anti-idling restrictions on heavy-duty vehicles 
had a cost effectiveness of over $400,000 per ton of SO2 
reduced).
---------------------------------------------------------------------------

    Accordingly, the EPA proposes to determine that Alaska has 
rectified the EPA's December 5, 2023, disapproval of the Fairbanks 
Serious Plan and initial Fairbanks 189(d) Plan with respect to control 
strategy requirements for mobile sources.
b. Alaska's Identification and Adoption of BACT for Major Stationary 
Sources
    Alaska submitted revisions to its BACM/BACT determinations for the 
five major stationary sources in the Fairbanks PM2.5 
Nonattainment Area, as described in the following paragraphs.\103\ 
Alaska also submitted permits for each of the five major

[[Page 1613]]

stationary sources that adopt and implement BACT for direct 
PM2.5.
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    \103\ State Air Quality Control Plan Vol. II, Appendix III.D.7.7 
(adopted November 5, 2024).
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i. Chena Power Plant
    Chena Power Plant is an existing stationary source owned and 
operated by Aurora Energy, LLC, which consists of four existing coal-
fired boilers: three 76 million British Thermal Units (MMBtu) per hour 
overfeed traveling grate stoker type boilers and one 269 MMBtu per hour 
spreader-stoker type boiler that burn coal to produce steam for heating 
and power (497 MMBtu per hour combined). The source also includes a 
coal preparation plant, coal stockpile, ash vacuum pump exhaust, and 
truck bay ash loadout.
    Alaska revised its State Air Quality Control Plan to include its 
BACT determinations for PM2.5 and SO2 for each of 
the emission units at the Chena Power Plant.\104\ We note that Alaska 
removed its BACT evaluation and determinations for NOX 
because the EPA approved a comprehensive NOX precursor 
demonstration. Alaska also submitted conditions from Air Quality 
Control Minor Permit AQ0315MSS02 Revision 1 for the Aurora Energy, 
LLC--Chena Power Plant (Aurora Permit). The Aurora Permit conditions 
include enforceable PM2.5 BACT emissions limitations for the 
emission units at the Chena Power Plant comprised of numerical 
emissions limits and work practice standards and associated monitoring, 
recordkeeping and reporting requirements. The permits are included in 
the docket for this action.\105\
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    \104\ See State Air Quality Control Plan, Vol. III, Appendix 
III.D.7.7-164. Note, Alaska's prior SIP submissions only evaluated 
BACT for the coal-fired boilers.
    \105\ See State Air Quality Control Plan, Vol. III, Appendix 
III.D.7.7-187.
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    The EPA previously reviewed Alaska's BACM/BACT evaluation for the 
Chena Power Plant.\106\ Alaska has since clarified that 
PM2.5 BACT for the coal-fired boilers is operating and 
maintaining fabric filters (full steam baghouse) during operation.\107\ 
Thus, in this action, the EPA is proposing to approve Alaska's 
PM2.5 BACT determinations for the Chena Power Plant, the 
submitted revisions to State Air Quality Control Plan, Vol. III, 
Appendix III.D.7.7, related to direct PM2.5 emissions and 
the submitted Aurora Permit conditions \108\ as satisfying CAA section 
189(b) and 40 CFR 51.1010.
---------------------------------------------------------------------------

    \106\ See Hedgpeth and Sorrels. (August 24, 2022). Review of 
Best Available Control Technology analyses submitted for the Aurora 
Energy, LLC Chena Power Plant as part of the Fairbanks PM2.5 
Nonattainment SIP. U.S. Environmental Protection Agency, Region 10, 
Laboratory Services and Applied Science Division, EPA-R10-OAR-2022-
0115.
    \107\ See State Air Quality Control Plan, Vol. III, Appendix 
III.D.7.7-173.
    \108\ See section III.A of this preamble for the specific permit 
conditions proposed for approval.
---------------------------------------------------------------------------

    The EPA is not proposing to take action on Alaska's SO2 
BACT determinations in State Air Quality Control Plan, Vol. III, 
Appendix III.D.7.7, at this time. As discussed in the preceding 
paragraphs, the EPA is proposing to approve Alaska's SO2 
precursor demonstration for major stationary sources. If approved, 
Alaska will not be required to identify, adopt, or implement 
SO2 BACT for the Chena Power Plant. If the EPA does not 
finalize approval of the SO2 precursor demonstration, then 
the EPA will propose action on Alaska's SO2 BACT 
determinations in a separate, future action.
ii. Doyon-Fort Wainwright Central Heating and Power Plant
    Fort Wainwright is an existing U.S. Army installation. Emission 
units located within the military installation include units such as 
boilers and generators that are owned and operated by the U.S. Army 
Garrison Alaska (referred to as FWA). The Central Heating and Power 
Plant (CHPP), also located within the installation footprint, is owned 
and operated by Doyon Utilities, LLC (DU), the regional Alaska Native 
corporation for Interior Alaska. The two entities, DU and FWA, comprise 
a single stationary source operating under two permits.
    The CHPP is comprised of six spreader-stoker type coal-fired 
boilers, each rated at 230 MMBtu per hour, that burn coal to produce 
steam for stationary source-wide heating and power. In addition to the 
CHPP, the source contains emission units comprised of small and large 
emergency engines, fire pumps, and generators, diesel-fired boilers, 
and material handling equipment. Alaska's BACM/BACT analysis in the 
Fairbanks Serious Plan for the stationary source evaluated potential 
controls to reduce NOX, PM2.5, and SO2 
emissions from each of these emissions units at the stationary 
source.\109\
---------------------------------------------------------------------------

    \109\ Alaska evaluated potential NOX controls for 
each emission unit, but because Alaska determined and the EPA 
approved that NOX emissions are not significant for 
PM2.5 formation in the Fairbanks PM2.5 
Nonattainment Area, Alaska does not plan to require implementation 
of BACT for NOX. See 88 FR 84626, December 5, 2023. Thus, 
EPA is not discussing Alaska's BACT analysis for NOX 
here.
---------------------------------------------------------------------------

    As part of the Fairbanks Revised 189(d) Plan, Alaska revised its 
Air Quality Control Plan sections related to the Doyon-Fort Wainwright 
CHPP to reflect new engines powering lift pumps and generators, correct 
typographical errors, improve clarity, and to include updated 
SO2 BACT determinations.\110\ With respect to the new 
engines, all are EPA-certified engines ranging in size from 74 
horsepower to 324 horsepower. Alaska updated its PM2.5 BACT 
determinations for these new engines. Alaska removed its BACT 
evaluation and determinations for NOX because the EPA 
approved a comprehensive NOX precursor demonstration.
---------------------------------------------------------------------------

    \110\ See State Air Quality Control Plan, Vol. III, Appendix 
III.D.7.7-202.
---------------------------------------------------------------------------

    Alaska also submitted conditions from two Air Quality Control Minor 
Permits: AQ0236MSS03 Revision 2 (U.S. Army Garrison--USAG Alaska Fort 
Wainwright) and AQ1121MSS04 Revision 1 (Doyon Utilities, LLC--Fort 
Wainwright) (collectively referred to as the Fort Wainwright Permits). 
The Fort Wainwright Permits include enforceable PM2.5 BACT 
emissions limitations for the emission units at Fort Wainwright 
comprised of numerical emissions limits and work practice standards and 
associated monitoring, recordkeeping and reporting requirements. The 
permits are included in the docket for this action.\111\
---------------------------------------------------------------------------

    \111\ See State Air Quality Control Plan, Vol. III, Appendix 
III.D.7.7-248.
---------------------------------------------------------------------------

    The EPA previously reviewed Alaska's BACM/BACT evaluation for the 
Doyon-Fort Wainwright Central Heating and Power Plant.\112\ In addition 
to the submitted conditions discussed in this section x.x.ii of this 
preamble, Alaska's updated BACT determination clarified the maintenance 
and testing requirements for the diesel-fired boilers and added 
enclosed conveying system requirements.\113\ The EPA previously 
approved Alaska's BACT determinations for older pump engines and 
generator engines. Alaska updated its BACT determinations and 
associated permit limits to reflect grams per hour emission limits 
appropriate to the size and model year of the engine. Alaska also 
imposed limits on the hours of operations of these engines. Thus, in 
this action, the EPA is proposing to approve Alaska's updated 
PM2.5 BACT determinations for the emissions units

[[Page 1614]]

at Doyon-Fort Wainwright CHPP,\114\ the submitted revisions to State 
Air Quality Control Plan, Vol. III, Appendix III.D.7.7 related to 
direct PM2.5 emissions from the Doyon-Fort Wainwright 
CHPP,\115\ and the submitted conditions from the Fort Wainwright 
Permits \116\ as satisfying CAA section 189(b) and 40 CFR 51.1010.
---------------------------------------------------------------------------

    \112\ See Hedgpeth, Z. (August 24, 2022). Review of Best 
Available Control Technology analyses submitted for Fort Wainwright-
US Army Garrison Alaska (FWA) and Doyon Utilities, LLC (DU) as part 
of the Fairbanks PM2.5 Nonattainment SIP. U.S. Environmental 
Protection Agency, Region 10, Laboratory Services and Applied 
Science Division, EPA-R10-OAR-2022-0115.
    \113\ See State Air Quality Control Plan, Vol. III, Appendix 
III.D.7.7-217; State Air Quality Control Plan, Vol. III, Appendix 
III.D.7.7-225.
    \114\ Industrial coal-fired boilers; diesel-fired boilers; 
diesel-fired engines, fire pumps, and generators; and material 
handling equipment.
    \115\ The EPA is not proposing to approve the NOX 
related emissions limits as meeting BACT for NOX. For 
some emission units, Alaska imposed NOX emissions limits 
as surrogates for direct PM2.5 emissions.
    \116\ See section III.A of this preamble for the specific permit 
conditions proposed to be approved.
---------------------------------------------------------------------------

    The EPA is not proposing to take action on Alaska's SO2 
BACT determinations in State Air Quality Control Plan, Vol. III, 
Appendix III.D.7.7 at this time for the same reasons discussed in the 
preceding paragraphs regarding the Chena Power Plant. If the EPA does 
not finalize approval of the SO2 precursor demonstration, 
then the EPA will propose action on Alaska's SO2 BACT 
determinations in a separate, future action.
iii. University of Alaska Fairbanks Campus Power Plant
    The Fairbanks Campus Power Plant is an existing stationary source 
owned and operated by the University of Alaska Fairbanks, which 
consists of two coal-fired boilers installed in 1962 that were later 
replaced by a circulating fluidized bed (CFB) dual fuel-fired boiler 
(coal and biomass) rated at 295.6 MMBtu per hour. Other emission units 
at the source include a backup diesel generator, diesel-fired boilers, 
engines, and a coal handling system for the new dual-fuel fired boiler.
    In the Fairbanks Revised 189(d) Plan, Alaska updated its Air 
Quality Control Plan regarding the Fairbanks Campus Power Plant to 
reflect permanently removed emission units, add new diesel boilers and 
engines, update the PM2.5 BACT determinations for small 
diesel-fired boilers and large and small engines, correct typographical 
errors, and improve clarity.\117\ Alaska also added updated 
SO2 BACT determinations for the Fairbanks Campus Power 
Plant.
---------------------------------------------------------------------------

    \117\ See State Air Quality Control Plan, Vol. III, Appendix 
III.D.7.7-356.
---------------------------------------------------------------------------

    With respect to the small diesel-fired boilers (EUs 17 through 22), 
Alaska updated its BACT determination for PM2.5 to consist 
of a partial limit on hours of operation, an emission limit of 0.016 
lb/MMBtu,\118\ compliance with 40 CFR part 63, subpart JJJJJJ, and work 
practice standards. Alaska evaluated whether installation of a scrubber 
was feasible for these boilers and determined that it was economically 
infeasible.\119\ Alaska noted that taking into consideration the 
enforceable limit on operation, the combined potential to emit of 
PM2.5 for the six boilers is two tons per year.
---------------------------------------------------------------------------

    \118\ Alaska noted that it previously selected a 0.012 lb/MMBtu 
limit erroneously. This limit is associated with industrial boilers 
while the boilers at the Fairbanks Campus Power Plant are commercial 
boilers.
    \119\ State Air Quality Control Plan, Vol. III, Appendix 
III.D.7.7-369.
---------------------------------------------------------------------------

    With respect to large diesel fired engines (EUs 8 and 35) and small 
diesel fired engines (EUs 24, 26, 27, 29, and 34), \120\ Alaska 
reevaluated the feasibility of add-on PM2.5 controls, namely 
a diesel particulate filter (DPF).\121\ EUs 24, 29, and 34 are limited 
to 100 hours per year of non-emergency operation, so additional BACT 
controls were not evaluated for these units. Alaska determined that a 
DPF is not technologically feasible for EU 8 due to an unacceptable 
increase in back pressure. Alaska determined that DPFs were 
technologically feasible for the other engines, but Alaska determined 
that the high cost per unit of emissions reductions rendered them 
economically infeasible. Updating the cost-effectiveness analysis to 
reflect comments from the EPA's Technical Support Document,\122\ Alaska 
determined that the cost-effectiveness ranged from over $17,000 at EU 
26 to over $20,000 per ton of PM2.5 reduced at EU 27. Alaska 
stated that EU 35 has potential PM2.5 emissions of 0.03 tons 
per year, which is an order of magnitude lower than the two other 
diesel engines, EUs 26 and 27. Therefore, Alaska did not perform a cost 
analysis for installing and operating a DPF on EU 35 as it would have 
an even higher cost per ton estimate than EUs 26 and 27. Furthermore, 
Alaska noted that EU 35 is limited to 100 hours per calendar year of 
non-emergency operation and required to combust ULSD under the existing 
Federal NSPS Subpart IIII requirements.\123\
---------------------------------------------------------------------------

    \120\ In comments, the University of Alaska Fairbanks clarified 
that EU 23 has been permanently removed from service and are no 
longer permitted EUs at the facility. See Comments on Proposed 
Rule--Air Plan Partial Approval and Partial Disapproval; AK, 
Fairbanks North Star Borough; 2006 24-Hour PM2.5 Serious 
Area and 189(d) Plan, at p. 9, Docket ID No. EPA-R10-OAR-2022-0115.
    \121\ State Air Quality Control Plan, Vol. III, Appendix 
III.D.7.7-372.
    \122\ See Hedgpeth and Sorrels. (August 24, 2022). Review of 
Best Available Control Technology analyses submitted for the 
University of Alaska, Fairbanks as part of the Fairbanks PM2.5 
Nonattainment SIP, p.15. U.S. Environmental Protection Agency, 
Region 10, Laboratory Services and Applied Science Division, EPA-
R10-OAR-2022-0115.
    \123\ State Air Quality Control Plan, Vol. III, Appendix 
III.D.7.7-374.
---------------------------------------------------------------------------

    Alaska removed its BACT evaluation and determinations for 
NOX because the EPA approved a comprehensive NOX 
precursor demonstration.\124\
---------------------------------------------------------------------------

    \124\ 88 FR 84626, December 5, 2023.
---------------------------------------------------------------------------

    Alaska also submitted conditions from Air Quality Control Minor 
Permit AQ0316MSS08 Revision 1 (University of Alaska Fairbanks (UAF)--
University of Alaska Fairbanks Campus) (UAF Permit). The UAF Permit 
conditions include enforceable PM2.5 BACT emissions 
limitations comprised of numerical emissions limits and work practice 
standards with associated monitoring, recordkeeping, and reporting. The 
permits are included in the docket for this action.\125\
---------------------------------------------------------------------------

    \125\ See State Air Quality Control Plan, Vol. III, Appendix 
III.D.7.7-414.
---------------------------------------------------------------------------

    The EPA previously reviewed Alaska's BACT evaluation for the 
Fairbanks Campus Power Plant.\126\ In this action, the EPA is proposing 
to approve Alaska's updated PM2.5 BACT determinations for 
the small diesel-fired boilers (EUs 17 through 22), large diesel-fired 
engines (EUs 8 and 35), and small diesel-fired engines (EUs 24, 26, 27, 
29, and 34) at the Fairbanks Campus Power Plant. The EPA previously 
approved Alaska's PM2.5 BACT determinations for EUs 8, 17-
19, 24, and 29. Alaska's updates are consistent with these past 
approvals. With respect to EUs 26, 27, and 35, the EPA proposes to 
approve Alaska's economic infeasibility demonstrations for DPFs. The 
EPA is proposing to approve Alaska's PM2.5 BACT emissions 
limits for small diesel-fired boilers (EUs 17 through 22), large 
diesel-fired engines (EUs 8 and 35), and small diesel-fired engines 
(EUs 24, 26, 27, 29, and 34) at the Fairbanks Campus Power Plant, which 
consist of numerical emissions limits, limits on operation, fuel 
requirements, and work practice standards.
---------------------------------------------------------------------------

    \126\ See Hedgpeth and Sorrels. (August 24, 2022). Review of 
Best Available Control Technology analyses submitted for the 
University of Alaska, Fairbanks as part of the Fairbanks PM2.5 
Nonattainment SIP. U.S. Environmental Protection Agency, Region 10, 
Laboratory Services and Applied Science Division, EPA-R10-OAR-2022-
0115.
---------------------------------------------------------------------------

    Therefore, the EPA proposes to approve the submitted revisions to 
State Air Quality Control Plan, Vol. III, Appendix III.D.7.7 related to 
direct PM2.5 emissions and NOX emissions \127\ 
from the Fairbanks Campus Power Plant

[[Page 1615]]

and the submitted conditions from the UAF Permit \128\ as satisfying 
CAA section 189(b) and 40 CFR 51.1010.
---------------------------------------------------------------------------

    \127\ The EPA is not proposing to approve the NOX 
related emissions limits as meeting BACT for NOX. For 
some emission units, Alaska imposed NOX emissions limits 
as surrogates for direct PM2.5 emissions.
    \128\ See section III.A of this preamble for the specific permit 
conditions proposed to be approved.
---------------------------------------------------------------------------

    The EPA is not proposing to take action on Alaska's SO2 
BACT determinations in State Air Quality Control Plan, Vol. III, 
Appendix III.D.7.7 at this time for the same reasons discussed in the 
preceding paragraphs regarding the Chena Power Plant. If the EPA does 
not finalize approval of the SO2 precursor demonstration, 
then the EPA will propose action on Alaska's SO2 BACT 
determinations in a separate, future action.
iv. Zehnder Facility
    The Zehnder Facility (Zehnder) is an electric generating facility 
that combusts distillate fuel in combustion turbines to provide power 
to the Golden Valley Electric Association (GVEA) grid. The power plant 
contains two fuel oil-fired simple cycle gas combustion turbines (each 
unit rated at 268 MMBtu per hour) and two diesel-fired generators 
(electro-motive diesels) used for emergency power and to serve as black 
start engines for the GVEA generation system. The primary fuel is 
stored in two 50,000 gallon above-ground storage tanks. Turbine startup 
fuel and electro-motive diesels primary fuel is stored in a 12,000 
gallon above ground storage tank.
    In the Fairbanks Revised 189(d) Plan, Alaska revised its Air 
Quality Control Plan for the Zehnder Facility to correct errors and 
improve clarity.\129\ Alaska also submitted conditions from Air Quality 
Control Minor Permit AQ0109MSS01 Revision 1 (Golden Valley Electric 
Association--Zehnder Facility) (Zehnder Permit). The Zehnder Permit 
contains enforceable PM2.5 BACT emissions limitations for 
the emission units at the Zehnder Facility comprised of numerical 
emissions limits and work practice standards with associated 
monitoring, recordkeeping, and reporting. The permits are included in 
the docket for this action.\130\
---------------------------------------------------------------------------

    \129\ State Air Quality Control Plan, Vol. III, Appendix 
III.D.7.7-316.
    \130\ See State Air Quality Control Plan, Vol. III, Appendix 
III.D.7.7-342.
---------------------------------------------------------------------------

    Similar to the small diesel-fired boilers (EUs 17 through 22) at 
the Fairbanks Campus Power Plant discussed in the preceding paragraphs 
of section II.C of this preamble, Alaska imposed, in the Fairbanks 
Serious Plan and Fairbanks 189(d) Plan, an erroneous emissions limit on 
the small diesel fired boilers at the Zehnder Facility. The revised Air 
Quality Control Plan and associated conditions in the Zehnder Permit 
reflect the corrected limit.\131\
---------------------------------------------------------------------------

    \131\ State Air Quality Control Plan, Vol. III, Appendix 
III.D.7.7-327.
---------------------------------------------------------------------------

    The EPA previously reviewed Alaska's BACT evaluation for the 
Zehnder Facility.\132\ In EPA's prior analysis, the EPA agreed with 
Alaska's BACT determinations for PM2.5. For the turbines, no 
technologically feasible add-on control options exist to reduce 
PM2.5 emissions. For the emergency generators, the EPA 
agreed that the limits on annual hours of operation of 100 hours per 
year or less will result in add-on control equipment such as DPF being 
cost prohibitive. Further, the EPA stated that similar to the turbines, 
no technologically feasible add-on control options exist to reduce 
PM2.5 emissions from the small diesel and propane fired 
boilers.\133\
---------------------------------------------------------------------------

    \132\ See Hedgpeth, Z. (August 24, 2022). Review of Best 
Available Control Technology analyses submitted for the Golden 
Valley Electric Association (GVEA) Zehnder and North Pole Power 
Plants as part of the Fairbanks PM2.5 Nonattainment SIP. U.S. 
Environmental Protection Agency, Region 10, Laboratory Services and 
Applied Science Division, EPA-R10-OAR-2022-0115.
    \133\ Id. at p. 11.
---------------------------------------------------------------------------

    Thus, in this action, the EPA proposes to approve the submitted 
revisions to State Air Quality Control Plan, Vol. III, Appendix 
III.D.7.7 related to direct PM2.5 emissions and 
NOX \134\ emissions from Zehnder and the submitted Zehnder 
Permit conditions as satisfying CAA section 189(b) and 40 CFR 51.1010.
---------------------------------------------------------------------------

    \134\ The EPA is not proposing to approve the NOX 
related emissions limits as meeting BACT for NOX. For 
some emission units, Alaska imposed NOX emissions limits 
as surrogates for direct PM2.5 emissions.
---------------------------------------------------------------------------

    The EPA is not proposing to take action on Alaska's SO2 
BACT determinations in State Air Quality Control Plan, Vol. III, 
Appendix III.D.7.7 at this time for the same reasons discussed in the 
preceding paragraphs regarding the Chena Power Plant. If the EPA does 
not finalize approval of the SO2 precursor demonstration, 
then the EPA will propose action on Alaska's SO2 BACT 
determinations in a separate, future action.
v. North Pole Power Plant
    The North Pole Power Plant is an electric generating facility that 
combusts distillate fuel in combustion turbines to provide power to the 
Golden Valley Electric Association (GVEA) grid. The power plant 
contains two fuel oil-fired simple cycle gas combustion turbines (each 
unit rated at 672 MMBtu per hour), two fuel oil-fired combined cycle 
gas combustion turbines (each unit rated at 455 MMBtu per hour), one 
fuel oil-fired emergency generator, and two propane-fired boilers.
    In the Fairbanks Revised 189(d) Plan, Alaska revised its Air 
Quality Control Plan for the North Pole Power Plant to correct errors 
and improve clarity.\135\ Alaska also submitted conditions from Air 
Quality Control Minor Permit AQ0110MSS01 Revision 1 (Golden Valley 
Electric Association--North Pole Power Plant) (NPPP Permit). The NPPP 
Permit conditions include enforceable PM2.5 BACT emissions 
limitations for the emission units at the North Pole Power Plant 
comprised of numerical emissions limits and work practice standards 
with associated monitoring, recordkeeping, and reporting. The permits 
are included in the docket for this action.\136\
---------------------------------------------------------------------------

    \135\ State Air Quality Control Plan, Vol. III, Appendix 
III.D.7.7-267.
    \136\ See State Air Quality Control Plan, Vol. III, Appendix 
III.D.7.7-300.
---------------------------------------------------------------------------

    The EPA previously reviewed Alaska's BACT evaluation for the North 
Pole Power Plant.\137\ Similar to the Zehnder facility discussion in 
the preceding paragraphs in this section II.C, the EPA agreed with 
Alaska that no additional PM2.5 BACT controls are feasible 
for emissions units at the North Pole Power Plant.\138\ Thus, in this 
action, the EPA proposes to approve the submitted revisions to State 
Air Quality Control Plan, Vol. III, Appendix III.D.7.7 related to 
direct PM2.5 emissions and NOX \139\ emissions 
from the North Pole Power Plant and the submitted NPPP Permit 
conditions \140\ as satisfying CAA section 189(b) and 40 CFR 51.1010.
---------------------------------------------------------------------------

    \137\ See Hedgpeth, Z. (August 24, 2022). Review of Best 
Available Control Technology analyses submitted for the Golden 
Valley Electric Association (GVEA) Zehnder and North Pole Power 
Plants as part of the Fairbanks PM2.5 Nonattainment SIP. U.S. 
Environmental Protection Agency, Region 10, Laboratory Services and 
Applied Science Division, EPA-R10-OAR-2022-0115.
    \138\ Id. at p. 11.
    \139\ The EPA is not proposing to approve the NOX 
related emissions limits as meeting BACT for NOX. For 
some emission units, Alaska imposed NOX emissions limits 
as surrogates for direct PM2.5 emissions.
    \140\ See section III.A of this preamble for the specific permit 
conditions proposed to be approved.
---------------------------------------------------------------------------

    The EPA is not proposing to take action on Alaska's SO2 
BACT determinations in State Air Quality Control Plan, Vol. III, 
Appendix III.D.7.7 at this time for the same reasons discussed in the 
preceding paragraphs regarding the Chena Power Plant. If the EPA does 
not finalize approval of the SO2 precursor demonstration, 
then the EPA will propose action on Alaska's SO2 BACT 
determinations separately.

[[Page 1616]]

c. Alaska's Identification and Adoption of Additional Measures and 
Demonstration of Five Percent Reduction in Emissions Pursuant to CAA 
Section 189(d)
    The Fairbanks Revised 189(d) Plan retained the identification of 
all sources of direct PM2.5 emissions and PM2.5 
plan precursors, identification of all potential controls to reduce 
direct PM2.5 emissions and PM2.5 plan precursors, 
and reevaluation of previously rejected control measures included in 
the initial Fairbanks 189(d) Plan, as well as identification of the 
MSMs adopted into any SIP or used in practice to control emissions in 
any state.
    As part of its reevaluation of control measures, Alaska provided 
additional information for many of the control measures considered in 
the BACM analysis. The Fairbanks Revised 189(d) Plan includes 
additional consideration of banning installation of solid-fuel devices 
in new construction, limiting heating oil to ultra-low sulfur diesel, 
dry wood requirements, emissions controls for small area sources, 
mobile sources, and MSMs.\141\
---------------------------------------------------------------------------

    \141\ State Air Quality Control Plan, Vol. II, section 
III.D.7.7.12 (adopted November 5, 2024).
---------------------------------------------------------------------------

    Alaska identified a burn-down period as part of other 
jurisdictions' solid fuel-fired heating device curtailment program. 
Accordingly, Alaska adopted a burn down period of three hours for 
solid-fuel heating devices that begins upon the effective date and time 
of a curtailment announcement. In addition, Alaska added specific 
requirements to document economic hardship as part of a NOASH 
curtailment program waiver for solid-fuel devices.
    Regarding the requirement to demonstrate five percent annual 
reductions, Alaska included in the Fairbanks Revised 189(d) Plan a 
control strategy analysis that demonstrates annual reductions of 
PM2.5 are greater than five percent through 2027, Alaska's 
projected attainment year.\142\ Alaska noted that the State can 
demonstrate either five percent annual reductions in emissions of 
direct PM2.5 or a five percent annual reductions in 
emissions of a PM2.5 plan precursor. Alaska elected to 
demonstrate five percent annual reductions in direct PM2.5 
emissions. Thus, the EPA is proposing to approve the control strategy 
included in the Fairbanks Revised 189(d) Plan as meeting the 
requirements of CAA section 189(d) and 40 CFR 51.1010(c).
---------------------------------------------------------------------------

    \142\ State Air Quality Control Plan, Vol. II, section 
III.D.7.9.2.3, Table 7.9-9.
---------------------------------------------------------------------------

D. Attainment Demonstration and Modeling

1. Statutory and Regulatory Requirements Regarding the Attainment 
Demonstration and Modeling
    Pursuant to CAA sections 188(c) and 189(b) and 40 CFR 51.1003(b) 
and 51.1011(b), for nonattainment areas reclassified as Serious, the 
state must submit an attainment demonstration as part of the Serious 
Plan that meets the requirements of 40 CFR 51.1011. Similarly, pursuant 
to 40 CFR 51.1003(c), for Serious areas subject to CAA section 189(d) 
for failing to attain by the Serious area attainment date, the state 
must submit an attainment demonstration as part of the 189(d) plan that 
meets the requirements of 40 CFR 51.1011. On September 2, 2020, the EPA 
determined that the Fairbanks PM2.5 Nonattainment Area 
failed to attain the 2006 24-hour PM2.5 NAAQS by the 
December 31, 2019, Serious area attainment date. Therefore, the EPA is 
proposing to evaluate any previously unmet Serious area planning 
obligations based on the current, applicable attainment date 
appropriate under CAA section 189(d) and not the original Serious area 
attainment date.\143\ In accordance with CAA section 172(a)(2)(A) and 
40 CFR 51.1004(a)(3), the projected attainment date for Serious 
nonattainment areas subject to CAA section 189(d) shall be as 
expeditious as practicable, but no later than five years following the 
effective date of the EPA's finding that the area failed to attain by 
the original Serious area attainment date, except that the 
Administrator may extend the attainment date to the extent the 
Administrator deems appropriate, for a period no greater than 10 years 
from the effective date of the EPA's determination that the area failed 
to attain, considering the severity of nonattainment and the 
availability and feasibility of pollution control measures. In 
accordance with 40 CFR 51.1011, the attainment demonstration must meet 
four requirements:
---------------------------------------------------------------------------

    \143\ The term ``applicable attainment date'' is defined at 40 
CFR 51.1000 to mean: ``the latest statutory date by which an area is 
required to attain a particular PM2.5 NAAQS, unless EPA 
has approved an attainment plan for the area to attain such NAAQS, 
in which case the applicable attainment date is the date approved 
under such attainment plan. If EPA grants an extension of an 
approved attainment date, then the applicable attainment date for 
the area shall be the extended date.''
---------------------------------------------------------------------------

    a. Identify the projected attainment date for the Serious 
nonattainment area that is as expeditious as practicable;
    b. Meet the requirements of 40 CFR part 51, appendix W and include 
inventory data, modeling results, and emissions reduction analyses on 
which the state has based its projected attainment date;
    c. The base year for the emissions inventories shall be one of the 
3 years used for designations or another technically appropriate 
inventory year if justified by the state in the plan submission; and
    d. The control strategies modeled as part of a Serious area 
attainment demonstration shall be consistent with the control 
strategies required pursuant to 40 CFR 51.1003 and 51.1010 (including 
the specific requirements in 40 CFR 51.1010(c)) for Serious areas that 
fail to attain.
    Further, in accordance with 40 CFR 51.1011(b)(5), the attainment 
plan must provide for implementation of all control measures needed for 
attainment as expeditiously as practicable. Additionally, all control 
measures must be implemented no later than the beginning of the year 
containing the applicable attainment date, notwithstanding the BACM 
implementation deadline requirements in 40 CFR 51.1010.\144\
---------------------------------------------------------------------------

    \144\ 40 CFR 51.1011(b)(5).
---------------------------------------------------------------------------

2. Summary of the EPA's Prior Rulemaking Regarding Attainment 
Demonstration and Modeling
    The EPA disapproved Alaska's attainment demonstration in the 
initial Fairbanks 189(d) Plan because it did not fully meet CAA 
requirements.\145\ As part of the attainment demonstration, the state 
must identify the projected attainment date that is as expeditious as 
practicable. Alaska did not adopt and implement all available control 
measures. The correct identification of the most expeditious attainment 
date requires an evaluation based upon expeditious implementation of 
the required emissions controls. Therefore, the EPA could not assess 
whether Alaska identified the expeditious attainment date for modeling 
purposes.
---------------------------------------------------------------------------

    \145\ 88 FR 84626, December 5, 2023, at p. 84676.
---------------------------------------------------------------------------

3. Summary of the State's Submission Regarding Attainment Demonstration 
and Modeling
    The State included an updated attainment demonstration in the 
Fairbanks Revised 189(d) Plan.\146\ In the plan, Alaska asserted that 
calendar year 2027 reflects attainment ``as expeditiously as 
practicable,'' based on air quality improvements from the base year to 
attainment year, as measured by the quantified emissions reductions

[[Page 1617]]

associated with the implementation of control measures.\147\
---------------------------------------------------------------------------

    \146\ State Air Quality Plan, Vol. II, section III.D.7.9 
(adopted November 5, 2024).
    \147\ State Air Quality Plan, Vol. II, section III.D.7.9.
---------------------------------------------------------------------------

    Alaska noted that for attainment modeling, five-year design values 
are generally recommended. For the earlier Fairbanks Serious Plan, the 
base year modeling design value was 131.6 [mu]g/m\3\. However, the 
latest five-year (2017-2021) design value is 64.9 [mu]g/m\3\ at the 
North Pole air quality monitor (Hurst Road), the area of expected 
highest PM2.5 concentrations in the Fairbanks 
PM2.5 Nonattainment Area. As part of updating its attainment 
analysis, Alaska identified this five-year design value of 64.9 [mu]g/
m\3\ as the base year modeling design value for the Fairbanks Revised 
189(d) Plan.
    Building on the 2020 base year emissions inventory, Alaska 
developed a series of future year emissions inventories for each 
calendar year from 2020 through 2029. Alaska noted that each of these 
future year inventories accounted for growth in source activity over 
time (e.g., increases in residential heating emissions resulting from 
forecasted housing growth). The emissions inventory also accounted for 
emissions reductions associated with both on-going state and local 
control programs (such as the Wood Stove Change Out and Solid Fuel-
Burning Appliance Curtailment programs), along with other control 
measures included in the SIP that were adopted since the area was 
classified as a Serious area.
    Alaska stated that source activity growth rates used to project the 
2020 base year inventory emissions in calendar years 2021 through 2029 
were generally based on the 2020-2024 and 2024-2035 annualized growth 
rates by source sector included in the Fairbanks Revised 189(d) 
Plan.\148\ However, Alaska noted that the source activity growth rate 
for space heating was capped after model year 2027, and claimed this is 
due to the difficulty in reliably forecasting long-term energy prices 
and the likely peak in energy costs in 2024. Alaska also stated that 
the effects of the Federal mobile source and fuel control programs in 
projecting mobile source emissions from 2021 through 2029 were 
accounted for using the EPA's MOVES3 vehicle emissions model.
---------------------------------------------------------------------------

    \148\ State Air Quality Plan, Vol. II, section III.D.7.6, Table 
7.6-10.
---------------------------------------------------------------------------

    Alaska included a list of the state and local control measures for 
which emissions benefits were quantified and included in the attainment 
date analysis.\149\ Further, Alaska included a phase-in forecast for 
each control measure for 2020-2027 inventory years. See Table 4 of this 
preamble for a summary of these control measures:
---------------------------------------------------------------------------

    \149\ State Air Quality Plan, Vol. II, section III.D.7.9, Table 
7.9-1.

                             Table 4--Alaska Control Measures and Phase-In Schedule
----------------------------------------------------------------------------------------------------------------
                                   Percent compliance      2027 Projected emissions (tons per
                               --------------------------             episodic day)
        Control measure                          2027    --------------------------------------      Details
                                 2020 Base    Attainment
                                    year         year           PM2.5               SO2
----------------------------------------------------------------------------------------------------------------
Fairbanks Wood Stove Change           2,791        5,628  1.09.............  0.11.............  Based on funding
 Out Program.                                                                                    from the 2016,
                                                                                                 2017, 2018,
                                                                                                 2019-2020,
                                                                                                 2021, and 2022
                                                                                                 Targeted
                                                                                                 Airshed Grants.
Solid Fuel-Burning Appliance            30%          38%  Stage 1: 0.02;     Stage 1:--0.000;   In winter 2022-
 Curtailment Program.                                      Stage 2: 0.12.     Stage 2:--0.02.    2023, Alaska
                                                                                                 conducted an
                                                                                                 observational
                                                                                                 field study
                                                                                                 from which
                                                                                                 compliance was
                                                                                                 estimated to be
                                                                                                 38.1%.
Shift to diesel no. 1 fuel oil          n/a          50%  0.02.............  1.73.............  This measure
                                                                                                 required a one-
                                                                                                 time shift from
                                                                                                 the current mix
                                                                                                 of diesel no. 2
                                                                                                 and diesel no.
                                                                                                 1 heating oil
                                                                                                 refined and
                                                                                                 sold in the
                                                                                                 nonattainment
                                                                                                 area by
                                                                                                 September 2022.
Requires commercially sold              n/a          50%  0.06.............  Less than 0.01...  Requires
 wood to be dry before sale.                                                                     commercially
                                                                                                 sold wood after
                                                                                                 October 1,
                                                                                                 2021, to be
                                                                                                 dry, or if sold
                                                                                                 as 8-ft length
                                                                                                 rounds,
                                                                                                 requires proof
                                                                                                 of proper/
                                                                                                 adequate
                                                                                                 storage for
                                                                                                 drying by the
                                                                                                 buyer.
Removal of all uncertified               0%          30%  0.25.............  -0.01............  2024 is first
 devices & cordwood outdoor                                                                      year of
 hydronic heaters.                                                                               implementation.
                                                                                                 Compliance rate
                                                                                                 estimates based
                                                                                                 on existing and
                                                                                                 on-going public
                                                                                                 education and
                                                                                                 outreach
                                                                                                 efforts.
2.0 g/hr and 0.10 lb/MMBtu              22%          35%  0.09.............  Less than 0.01...  The compliance
 certified emission rates for                                                                    rate estimated
 new or re-conveyed wood                                                                         for this
 devices.                                                                                        measure reflect
                                                                                                 the volume of
                                                                                                 home sales
                                                                                                 (projected from
                                                                                                 historical
                                                                                                 data) coupled
                                                                                                 with the
                                                                                                 requirement to
                                                                                                 register wood-
                                                                                                 fired heating
                                                                                                 devices upon
                                                                                                 sale or
                                                                                                 conveyance of a
                                                                                                 property.
Removal of coal heaters.......          n/a          25%  Less than 0.01...  Less than 0.01...

[[Page 1618]]

 
Wood-fired devices may not be            0%          20%  0.09.............  Less than 0.01...  Beginning in
 primary or only heating                       (existing                                         2024,
 source.                                     homes); 40%                                         compliance
                                             (new homes)                                         rates of 20%
                                                                                                 for new home
                                                                                                 sales
                                                                                                 (discounted for
                                                                                                 large lot, 2-
                                                                                                 acre cabin
                                                                                                 exemption) and
                                                                                                 40% for home
                                                                                                 resales. The
                                                                                                 new home sale
                                                                                                 compliance rate
                                                                                                 is discounted
                                                                                                 from 40% to 20%
                                                                                                 to account for
                                                                                                 the estimated
                                                                                                 portion of
                                                                                                 large lot
                                                                                                 (greater than 2
                                                                                                 acre) cabins
                                                                                                 which are
                                                                                                 exempted from
                                                                                                 this
                                                                                                 requirement.
NOASH/Exemption requirements..           0%          50%  Less than 0.01...  Less than 0.01...  Compliance rates
                                                                                                 reflect
                                                                                                 projected
                                                                                                 penetration
                                                                                                 rate increases
                                                                                                 associated with
                                                                                                 annual renewal
                                                                                                 and device
                                                                                                 registration
                                                                                                 requirements,
                                                                                                 proper
                                                                                                 installation
                                                                                                 and maintenance
                                                                                                 determinations
                                                                                                 from third-
                                                                                                 party
                                                                                                 verifiers, and
                                                                                                 requirements
                                                                                                 for catalyst
                                                                                                 replacement
                                                                                                 when
                                                                                                 manufacturer-
                                                                                                 recommended
                                                                                                 catalyst useful
                                                                                                 life is reached
                                                                                                 (estimated at
                                                                                                 six years
                                                                                                 averaged across
                                                                                                 manufacturers).
                                                                                                 These elements
                                                                                                 are also
                                                                                                 coupled with
                                                                                                 projected
                                                                                                 impacts from
                                                                                                 the NOASH
                                                                                                 reduction
                                                                                                 program funded
                                                                                                 under currently
                                                                                                 secured TAGs.
----------------------------------------------------------------------------------------------------------------

    Alaska noted that, based on these phase-in forecasts, a detailed 
spreadsheet was developed to calculate PM2.5 and 
SO2 emissions reductions within the space heating sector for 
each measure in each inventory year. \150\ The source activity data 
includes device and fuel splits, emission factors, and methods used to 
calculate control measure emissions benefits to support the control 
inventories developed for the attainment date analysis. Alaska further 
stated that the control measure emissions benefits calculations also 
account for the effects of overlap between measures that impact the 
same source category, properly eliminating double counting.
---------------------------------------------------------------------------

    \150\ See State Air Quality Plan, Vol. III, Appendix III.D.7.9.
---------------------------------------------------------------------------

    Alaska stated that projected emissions control inventories for each 
year from 2020 through 2029 were prepared to support the analysis of 
expeditious attainment. Full modeling runs were completed for 2029, 
2027, and 2026 in that order. After the 2029 modeling results 
demonstrated attainment of the PM2.5 NAAQS, 2027 was 
selected as the next year to evaluate expeditious attainment.
    To begin analyzing the 2027 attainment year, Alaska noted that the 
2027 episodic modeling inventory was incorporated into the CMAQ air 
quality model. Modeled concentration outputs for this 2027 control 
inventory run were post-processed for each grid cell corresponding to 
ambient air quality monitors for which design values could be computed 
and processed through Alaska's Speciated Modeled Attainment Test (SMAT) 
tool (see State Air Quality Control Plan, Vol. II, section 
III.D.7.8.9). Alaska stated that the modeled design value at the 
controlling North Pole (Hurst Road) air quality monitor was found to be 
31.9 [mu]g/m\3\, below the 35 [mu]g/m\3\ NAAQS for 24-hour 
PM2.5 and thus demonstrating modeled attainment by 2027.
    To evaluate whether attainment could be advanced any sooner than 
2027, Alaska compiled another emissions inventory for the 2026 model 
year. The 2026 CMAQ gridded outputs were then post-processed for the 
key monitor-based grid cells through the SMAT tool to develop modeled 
design values that reflected penetration of the State's control 
strategy package in 2026. Alaska stated that the 2026 modeled design 
value at the North Pole (Hurst Road) monitor was found to be 38.1 
[mu]g/m\3\, which exceeds the 35 [mu]g/m\3\ NAAQS.
    As shown in Table 5 of this preamble, modeled design values in 2027 
at all three regulatory air quality monitor locations in the Fairbanks 
PM2.5 Nonattainment Area are below the 35 [mu]g/m\3\ 24-hour 
PM2.5 NAAQS. Alaska noted that the modeled design value at 
the controlling North Pole (Hurst Road) monitor is 31.9 [mu]g/m\3\, 
more than 3 [mu]g/m\3\ below the NAAQS, which provides a ``buffer'' to 
account for concentrations in unmonitored grid cells across the 
nonattainment area. Modeled 2027 design values at the other two 
monitors near downtown Fairbanks are well below the PM2.5 
NAAQS.

[[Page 1619]]



                                  Table 5--Fairbanks Modeled Attainment Summary
----------------------------------------------------------------------------------------------------------------
                                                         Base year 2020 5-    Future 5-year      Future 5-year
                                                             year PM2.5       PM2.5 modeling     PM2.5 modeling
          Fairbanks PM2.5 air quality  monitor            modeling design      design value       design value
                                                          value ([micro]g/   ([micro]g/m\3\),   ([micro]g/m\3\),
                                                         m\3\),  2017-2021         2026               2027
----------------------------------------------------------------------------------------------------------------
North Pole (Hurst Road)................................               64.9               38.1               31.9
NCORE..................................................               27.7               19.8               18.4
A Street...............................................               34.8               24.5               22.7
----------------------------------------------------------------------------------------------------------------
Source: State Air Quality Plan, Vol. II, section III.D.7.9, Table 7.9-12.

    Alaska noted that even if emission controls were applied for 
precursor pollutants within applicable source sectors for which 
precursor significance determinations have been made (i.e., 
SO2 emissions from major stationary sources in the Fairbanks 
PM2.5 Nonattainment Area), the reduction in secondary 
PM2.5 from such controls would not be sufficient to advance 
attainment sooner than 2027.\151\
---------------------------------------------------------------------------

    \151\ State Air Quality Control Plan, Vol. II, section 
III.D.7.9.3
---------------------------------------------------------------------------

    Therefore, Alaska asserted that this evaluation demonstrates that 
2027 is the most expeditious attainment date based on currently 
available data and demonstrate attainment ``as expeditiously as 
practicable.''
4. The EPA's Evaluation and Proposed Action Regarding the Attainment 
Demonstration and Modeling
    The EPA proposes to approve Alaska's attainment demonstration as 
meeting the requirements under 40 CFR 51.1011(b). Alaska demonstrated 
that the 2027 projected attainment date for the Serious nonattainment 
area is as expeditious as practicable. The attainment demonstration 
meets the requirements of Appendix W and includes inventory data, 
modeling results, and emissions reduction analyses on which the state 
has based its projected attainment date. As discussed in section II.A 
of this preamble, the base year for the emissions inventories for 
Alaska was 2020, which the EPA is proposing to determine is the 
technically appropriate inventory year. The EPA is proposing to 
determine that the control strategies in Alaska's SIP as rectified by 
the Fairbanks Revised 189(d) Plan satisfy the requirements of 40 CFR 
51.1010. Therefore, the control strategies modeled as part of the 
attainment demonstration are consistent with the control strategies 
required pursuant to 40 CFR 51.1003 and 51.1010. With respect to the 
required timeframe for obtaining emissions reductions, all control 
measures needed for attainment will be implemented as expeditiously as 
practicable and implemented to attain the PM2.5 NAAQS by 
2027.
    Pursuant to CAA section 172(a)(2)(A) and 40 CFR 51.1004(a)(3), the 
EPA is proposing to extend the attainment date for the Fairbanks 
PM2.5 Nonattainment Area to December 31, 2027. As shown in 
Table 5 of this preamble, the 2020 base year design value at the Hurst 
Road monitoring station is 64.9 [micro]g/m\3\. This design value is 
well above the PM2.5 24-hour NAAQS of 35 [micro]g/m\3\, 
indicating the air quality problem in the Fairbanks PM2.5 
Nonattainment Area remains severe. However, Alaska has demonstrated 
that attainment earlier than 2027 is not feasible. Moreover, the EPA 
has reviewed Alaska's evaluations (and re-evaluations) of available 
control measures and proposes to determine that Alaska's control 
strategy meets the requirements of CAA section 189(b) and 189(d) and 40 
CFR 51.1010. By extension, the EPA proposes to determine that there are 
no other feasible measures that Alaska could implement that would 
advance attainment to a date earlier than December 31, 2027.
    As discussed in section II.E of this preamble regarding Reasonable 
Further Progress, the primary drivers of emissions reductions will be 
continued implementation of the wood stove change out program, the 
Solid Fuel-Burning Appliance Curtailment Program, and the switch from 
diesel no. 2 fuel oil to diesel no. 1 fuel oil. The rate of wood stove 
change-outs in a single season is constrained based on the availability 
of certified installers and residential demand. Similarly, higher 
sulfur fuel cannot feasibly be eliminated from the Fairbanks 
PM2.5 Nonattainment Area until 2026 \152\ due to the time 
necessary to expend all residual diesel no. 2 fuel oil and for diesel 
no. 1 to fully flush out any remaining higher sulfur residue. Finally, 
Alaska conducted a recent assessment of compliance with the Solid Fuel-
Burning Appliance Curtailment Program that indicated a compliance rate 
of 38 percent.\153\ Given the variability of compliance with this 
program in past, Alaska does not project a near-term improvement in the 
compliance rate. Therefore, the EPA has considered the severity of 
nonattainment and the availability and feasibility of control measures 
as required under CAA section 172(a)(2)(A) and 40 CFR 51.1004(a)(3).
---------------------------------------------------------------------------

    \152\ State Air Quality Control Plan, Vol. II, section 
III.D.7.10, Table 7.10-4.
    \153\ State Air Quality Control Plan, Vol. III, Appendix 
III.D.7.9, at p. Appendix III.D.7.14-12.
---------------------------------------------------------------------------

E. Reasonable Further Progress

1. Statutory and Regulatory Requirements Regarding Reasonable Further 
Progress
    Pursuant to CAA section 172(c) and 40 CFR 51.1012, each attainment 
plan for a PM2.5 nonattainment area shall include Reasonable 
Further Progress (RFP) provisions that demonstrate that control 
measures in the area will achieve such annual incremental reductions in 
emissions of direct PM2.5 and PM2.5 plan 
precursors as are necessary to ensure attainment of the applicable 
PM2.5 NAAQS as expeditiously as practicable. As discussed in 
section I of this preamble, on September 2, 2020, the EPA determined 
that the Fairbanks PM2.5 Nonattainment Area failed to attain 
the 2006 24-hour PM2.5 NAAQS by the applicable December 31, 
2019, Serious area attainment date. Therefore, the EPA is proposing to 
evaluate any previously unmet Serious area planning obligations, 
including RFP and quantitative milestone requirements, based on the 
current, applicable attainment date appropriate under CAA section 
189(d) and not the original Serious area attainment date. In accordance 
with 40 CFR 51.1012, the RFP plan shall include all of the following:
    a. A schedule describing the implementation of control measures 
during each year of the applicable attainment plan. Control measures 
for Moderate area attainment plans are required in 40 CFR 51.1009, and 
control

[[Page 1620]]

measures for Serious area attainment plans are required in 40 CFR 
51.1010.
    b. RFP projected emissions for direct PM2.5 and all 
PM2.5 plan precursors for each applicable milestone year, 
based on the anticipated implementation schedule for control measures 
required by 40 CFR 51.1009 and 51.1010. For purposes of establishing 
motor vehicle emissions budgets for transportation conformity purposes 
(as required in 40 CFR part 93, subpart A) for a PM2.5 
nonattainment area, the state shall include in its RFP submission an 
inventory of on-road mobile source emissions in the nonattainment area 
for each milestone year.\154\
---------------------------------------------------------------------------

    \154\ For an evaluation of motor vehicle emission budgets, see 
section II.H of this preamble.
---------------------------------------------------------------------------

    c. An analysis that presents the schedule of control measures and 
estimated emissions changes to be achieved by each milestone year, and 
that demonstrates that the control strategy will achieve reasonable 
progress toward attainment between the applicable base year and the 
attainment year. The analysis shall rely on information from the base 
year inventory for the nonattainment area required in 40 CFR 
51.1008(a)(1) and the attainment projected inventory for the 
nonattainment area required in 40 CFR 51.1008(a)(2), in addition to the 
RFP projected emissions required in 40 CFR 51.1012(a)(2).
    d. An analysis that demonstrates that by the end of the calendar 
year for each milestone date for the area determined in accordance with 
40 CFR 51.1013(a), pollutant emissions will be at levels that reflect 
either generally linear progress or stepwise progress in reducing 
emissions on an annual basis between the base year and the attainment 
year. A demonstration of stepwise progress must be accompanied by 
appropriate justification for the selected implementation schedule.
2. Summary of the EPA's Prior Rulemaking Regarding Reasonable Further 
Progress
    The EPA disapproved the RFP provisions in the Fairbanks Serious 
Plan and Fairbanks 189(d) Plan because the control strategies in those 
prior plans did not include all required control measures.\155\ This 
caused uncertainty as to whether the RFP provisions of those plans 
accurately projected progress towards the most expeditious attainment 
year, per CAA section 172(c)(2) and 40 CFR 51.1012.
---------------------------------------------------------------------------

    \155\ 88 FR 84626, December 5, 2023, at p. 84676.
---------------------------------------------------------------------------

3. Summary of the State's Submission Regarding Reasonable Further 
Progress
    The Fairbanks Revised 189(d) Plan includes updated RFP provisions 
at State Air Quality Control Plan, Vol. II, section III.D.7.10.\156\ 
Consistent with the attainment demonstration provisions discussed in 
the preceding paragraphs, these updated RFP provisions reflect the 
attainment year of 2027.\157\ The updated RFP analysis includes a 
schedule that includes 2020 as the base year, 2027 as the attainment 
year, and the following years as RFP and quantitative milestone 
analysis years: 2023, 2026, and 2029.\158\
---------------------------------------------------------------------------

    \156\ Adopted November 5, 2024.
    \157\ RFP provisions in prior SIP submissions for the Fairbanks 
PM2.5 Nonattainment Area reflected varying projected 
attainment dates. Initially Alaska submitted an RFP plan in the 
Fairbanks Serious Plan based on the projected attainment year of 
2029. Alaska withdrew and replaced the RFP plan in the Fairbanks 
189(d) plan based on the revised 2024 attainment projection.
    \158\ See State Air Quality Plan, Vol. II, section III.D.7.10.2.
---------------------------------------------------------------------------

    Alaska included an analysis of implementation of all control 
measures that establishes the scheduled phase-in of each measure 
adopted and estimation of emissions reductions for each significant 
pollutant (also accounting for the overlapping of measures to eliminate 
double counting) for each milestone year based on the phase-in 
schedule. Alaska calculated the RFP and quantitative milestone (QM) 
milestone year emissions reduction targets based on linear progress 
towards attainment by 2027. Based on the control measure phase-in 
schedule, Alaska calculated projected emissions reductions for each 
pollutant in each milestone year and compared these emissions 
reductions to their targets to evaluate linear progress toward 
attainment.
    Alaska has continued to assess the appropriate compliance rate 
estimate. As Alaska noted in the Fairbanks Revised 189(d) Plan, the 
State is currently utilizing funding from the 2019-2020 TAG to purchase 
three dynamic message highway signs and an infrared camera and to 
expand staffing to increase compliance.\159\ Alaska continues to 
conduct field studies during the wintertime to observe compliance 
rates. Based on the recent 2022-2023 wintertime field study, Alaska 
determined that the combined compliance rate in Fairbanks and the North 
Pole is 38.1 percent. Based on these observations and the increased use 
of TAG funding to improve compliance, Alaska increased its compliance 
estimate with the curtailment program to 38 percent for the 2023 model 
year, an increase from 30 percent in 2020. Alaska plans to conduct 
additional wintertime curtailment program compliance observations to 
inform anticipated improvements in compliance beyond 2023. For the 
attainment year projected emissions inventory, Alaska stated that it 
conservatively assumed no further compliance rate increases pending 
further evaluation of additional wintertime compliance 
observations.\160\
---------------------------------------------------------------------------

    \159\ State Air Quality Plan, Vol. II, section III.D.7.9.1.1.
    \160\ Id.
---------------------------------------------------------------------------

    Alaska stated that direct PM2.5 emissions reductions 
achieved within the first two milestone years (2023 and 2026) achieve 
stepwise progress.\161\ However, reductions in direct PM2.5 
emissions in the attainment year of 2027 reflect linear progress. 
According to Alaska's submission, this is attributable to a spike in 
participation in the wood stove change out program anticipated by 2027 
(based on increased incentives and deadlines for older device turnover) 
and gradual improvements in household compliance with control 
strategies impacting solid fuel-burning devices.
---------------------------------------------------------------------------

    \161\ State Air Quality Plan, Vol. II, section III.D.7.10.3.3.
---------------------------------------------------------------------------

    With respect to SO2, Alaska stated that SO2 
emissions reductions are expected to be non-linear but includes early 
year (2023 and 2026) progress that significantly exceeds the linear 
progress trajectory.\162\ Alaska stated that this non-linearity in 
control measure reductions for SO2 is due to two causes. 
First, most of the measures designed to reduce direct PM2.5 
through removal, curtailment, or replacement of solid-fuel devices 
trigger a shift from space heating devices that emit high levels of 
direct PM2.5 to oil-fired devices that emit very low levels 
of direct PM2.5 (but can lead to higher levels of 
SO2 emissions depending on the fuel sulfur content). Second, 
initial reductions in SO2 emissions are the result of Alaska 
implementing an SO2-specific control measure in 2022 
mandating a shift from diesel no. 2 to diesel no. 1 heating oil. Thus, 
emissions reductions for SO2 exhibit stepwise rather than 
linear progress.
---------------------------------------------------------------------------

    \162\ Id.
---------------------------------------------------------------------------

    Regarding NH3, Alaska stated that linearly established 
targets for NH3 will not be met until the forecasted 2027 
attainment year.\163\ Alaska noted that the increases in NH3 
emissions are not due to control measure benefits or lack thereof. 
Although Alaska adopted and implemented control measures to reduce 
NH3, Alaska did not calculate any NH3 emissions 
reductions for these measures for the purposes of RFP due to

[[Page 1621]]

the large uncertainty in NH3 emissions factors for key 
sources.
---------------------------------------------------------------------------

    \163\ Id.
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4. The EPA's Evaluation and Proposed Action Regarding Reasonable 
Further Progress
    The EPA is proposing to approve the Fairbanks Revised 189(d) Plan 
as meeting the RFP requirements in CAA section 172(c)(2) and 40 CFR 
51.1012. The RFP provisions in the Fairbanks Revised 189(d) Plan meet 
each of the requirements in 40 CFR 51.1012(a)(1)-(4). First, the RFP 
provisions include a schedule describing the implementation of control 
measures during each year of the applicable attainment plan.\164\ 
Second, the Fairbanks Revised 189(d) Plan includes RFP projected 
emissions for direct PM2.5 and all PM2.5 plan 
precursors for each applicable milestone year based on the phase-in 
schedule.\165\ Third, the Fairbanks Revised 189(d) Plan includes an 
analysis that presents the schedule of control measures and estimated 
emissions changes to be achieved by each milestone year: 2023, 2026, 
and 2029.\166\ This analysis relies on information from the base year 
inventory and attainment projected inventories in State Air Quality 
Control Plan, Vol. II, section III.D.7.8, as well as the RFP projected 
emissions. The analysis demonstrates that the control strategy will 
achieve reasonable progress toward attainment between the applicable 
base year and the attainment year.\167\
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    \164\ Id. at section III.D.7.10.3.2; See also State Air Quality 
Control Plan, Vol. III, Appendix III.D.7.10.
    \165\ Id. at section III.D.7.10.3.3, Table 7.10-5.
    \166\ Id. at section III.D.7.10.3.2, Table 7.10-4.
    \167\ Id. at section III.D.7.10.3, Tables 7.10-4-7.10-5; Figures 
7.10-3-7.10-5. Note that NH3 emissions are projected to 
increase from base year to the projected attainment year. As 
discussed in the preceding paragraphs regarding the control 
strategy, the EPA either has previously approved Alaska's control 
strategy as meet planning requirements for sources of 
NH3. This is primarily because there are either no 
controls for sources of NH3 emissions in the Fairbanks 
PM2.5 Nonattainment Area or the direct PM2.5 
emissions controls are sufficient to control NH3 
emissions.
---------------------------------------------------------------------------

    Finally, the Fairbanks Revised 189(d) Plan includes an analysis 
that demonstrates that by the end of the calendar year for each 
milestone date, pollutant emissions will be at levels that reflect 
either linear progress or stepwise progress in reducing emissions on an 
annual basis between the base year and attainment year. As discussed in 
section II.E.3 of this preamble, Alaska's projections for reductions in 
direct PM2.5 reductions closely track linear progress. The 
EPA proposes to determine that the slight deviations from linear 
progress in the initial years of implementation are justified. The EPA 
recognizes the episodic nature of wood-stove change outs and the time 
lag between state enforcement and deterrence.
    With respect to SO2 emissions reductions, Alaska 
projects emissions well below linear progress in 2023 and 2026 
milestone years. As discussed in section II.E.3 of this preamble, the 
early-year reductions are due to near-term implementation of the 
control strategy requirement to switch to lower sulfur fuels. These 
early reductions are consistent with the overall goal of achieving 
attainment as expeditiously as practicable.\168\ The EPA proposes to 
determine that Alaska adequately justified the leveling off of 
SO2 emissions reductions in 2027 as due to the near-term 
implementation of the fuel switch as well as the increase in 
SO2 emissions from residents switching from solid fuel-fired 
heating devices to liquid fuel-fired heating devices to comply with 
other measures in the control strategy targeting sources of direct 
PM2.5.
---------------------------------------------------------------------------

    \168\ See CAA section 189, 42 U.S.C. 7513a, Addendum to the 
General Preamble, 59 FR 41998 (August 16, 1994), at p. 42016.
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    Finally, with respect to NH3, the EPA proposes to 
determine that Alaska adequately justified the increase in emissions. 
The EPA has previously approved Alaska control strategy for 
NH3, noting that sources in the Fairbanks PM2.5 
Nonattainment Area emit a negligible amount of NH3 and there 
are no specific controls for the types of sources in the area.\169\ 
Therefore, the EPA is proposing to approve the Fairbanks Revised 189(d) 
Plan as meeting the RFP requirements in CAA section 172(c)(2) and 40 
CFR 51.1012.
---------------------------------------------------------------------------

    \169\ 88 FR 84626, December 5, 2023, at p. 84636
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F. Quantitative Milestones

1. Statutory and Regulatory Requirements Regarding the Quantitative 
Milestones
    In accordance with CAA section 189(c)(1) and 40 CFR 51.1013, the 
state must submit in each attainment plan for a PM2.5 
nonattainment area specific quantitative milestones that provide for 
objective evaluation of RFP toward timely attainment of the applicable 
PM2.5 NAAQS in the area.
    For an attainment plan submission for a Serious area subject to the 
requirements of CAA section 189(d) and 40 CFR 51.1003(c), each plan 
shall contain quantitative milestones that provide for objective 
evaluation of reasonable further progress toward timely attainment of 
the applicable PM2.5 NAAQS in the area.\170\ At a minimum, 
each plan for an area subject to CAA section 189(d) must include QMs 
for tracking progress achieved in implementing the SIP control measures 
by each milestone date.\171\
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    \170\ 40 CFR 51.1013(a)(3).
    \171\ 40 CFR 51.1013(a)(3)(ii).
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    In the preamble to the PM2.5 SIP Requirements Rule, the 
EPA stated that it interprets the CAA as allowing states to identify 
milestones that are suitable for the specific facts and circumstances 
of the attainment area.\172\ The EPA suggested possible metrics, 
including tracking air quality improvement, tracking emissions 
reductions, percentage implementation of control strategies, or percent 
compliance with implemented control measures.\173\ Finally, the EPA 
stated in the preamble that quantitative milestones will be met by 
showing that emissions reductions scheduled to be made between the SIP 
due date and the attainment date were actually achieved.\174\
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    \172\ Id.
    \173\ 81 FR 58010, Aug. 24, 2016, at pp. 58064, 58104.
    \174\ Id.
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    Regarding the specific timeframe for the Fairbanks PM2.5 
Nonattainment Area, per 40 CFR 51.1013(a)(4), each attainment plan 
submission for an area designated nonattainment for the 1997 and/or 
2006 PM2.5 NAAQS before January 15, 2015, shall contain 
quantitative milestones to be achieved no later than 3 years after 
December 31, 2014, and every 3 years thereafter until the milestone 
date that falls within 3 years after the applicable attainment date.
2. Summary of the EPA's Prior Action Regarding the Quantitative 
Milestones
    The EPA disapproved the quantitative milestones in the Fairbanks 
Serious Plan and Fairbanks 189(d) Plan because the control strategies 
in those prior plans did not include all required control 
measures.\175\ This caused uncertainty as the whether the quantitative 
milestones were based on progress towards the most expeditious 
attainment year.
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    \175\ 88 FR 84626, December 5, 2023, at p. 84676.
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3. Summary of the State's Submission Regarding the Quantitative 
Milestones
    Alaska submitted revised quantitative milestones in the Fairbanks 
Revised 189(d) Plan. As noted in section II.E of this preamble, 
Alaska's updated RFP analysis is based on a schedule that includes 2020 
as the base year, 2027 as the attainment year, and the following years 
as quantitative milestone years:

[[Page 1622]]

2023, 2026, and 2029.\176\ Alaska used emissions reductions achieved 
compared to projected emissions reductions as the metric to objectively 
evaluate progress toward attainment.\177\ Alaska calculated expected 
emissions reductions based on the control measure phase-in 
schedule.\178\ In its Quantitative Milestone Reports required by CAA 
section 189(c) and 40 CFR 51.1013(b), Alaska reported the emissions 
reductions achieved by the end of the milestone year compared to the 
projected emissions reductions included in the quantitative milestone 
provisions in the Fairbanks Revised 189(d) Plan, specifically, State 
Air Control Quality Plan, Vol. II, section III.D.7.10.3. Alaska made 
clear that the state will include in its QM reports completion 
statistics and phase-in percentages for each measure included in the 
Fairbanks Revised 189(d) Plan.\179\
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    \176\ See State Air Quality Control Plan, Vol. II, section 
III.D.7.10.2.
    \177\ Id.
    \178\ Id. at section III.D.7.10.3.3, Table 7.10-5.
    \179\ Id. at section III.D.7.10.2.
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    According to the Fairbanks Revised 189(d) Plan, one of Alaska's 
reasons for selecting emissions reductions achieved compared to 
projected emissions reductions as the objective metric is because doing 
so allows Alaska to take credit for emissions reductions from voluntary 
measures that are not part of its control strategy.\180\ Alaska 
provided the example of emissions reductions attributable to natural 
gas expansion. As discussed further below in section II.F.4 of this 
preamble, the EPA disagrees with this specific rationale for allowing 
the state to take credit for emissions reductions from voluntary 
measures that are not part of its control strategy.
---------------------------------------------------------------------------

    \180\ Id.
---------------------------------------------------------------------------

4. The EPA's Evaluation and Proposed Action Regarding the Quantitative 
Milestones
    The EPA is proposing to approve the Fairbanks Revised 189(d) Plan 
as meeting the quantitative milestone requirements of CAA section 
189(c)(1) and 40 CFR 51.1013. First, in accordance with 40 CFR 
51.1013(a)(3)(ii) and (4), the Fairbanks Revised 189(d) Plan includes 
quantitative milestones for the years 2023, 2026, and 2029. Second, the 
Fairbanks Revised 189(d) Plan includes phase-in metrics for each 
measure in the control strategy, including measures necessary to meet 
the BACM and BACT requirements in CAA section 189(b) and 40 CFR 
51.1010(a) and the requirements of CAA section 189(d) and 40 CFR 
51.1010(c).
    Finally, the measures allow for objective evaluation of RFP. As 
stated in the preceding paragraphs, the EPA interprets the CAA as 
allowing states to identify milestones that are suitable for the 
specific facts and circumstances of the attainment area. The EPA 
proposes to determine that Alaska's quantitative milestones provide 
objective evaluation of RFP and are suitable for the specific facts and 
circumstances for the Fairbanks PM2.5 Nonattainment Area. 
Although the EPA agrees that comparing emissions reductions achieved to 
projected emissions reductions allows for objective evaluation of RFP 
for the Fairbanks PM2.5 Nonattainment Area, the EPA 
disagrees with Alaska's stated rationale for selecting this metric. The 
purpose of QMs is to provide an objective evaluation of the state's 
implementation of the SIP control measures.\181\ Therefore, crediting 
emissions reductions attributable to non-SIP measures toward achieving 
a QM is inconsistent with CAA section 189(c) and 40 CFR 51.1013.
---------------------------------------------------------------------------

    \181\ See 40 CFR 51.1013(a)(3)(ii) (``At a minimum, each 
quantitative milestone plan must include a milestone for tracking 
progress achieved in implementing the SIP control measures by each 
milestone date.'') (emphasis added).
---------------------------------------------------------------------------

    Nevertheless, using emissions reductions as the metric is 
appropriate for the Fairbanks Revised 189(d) Plan because of the 
overlapping nature of control measures and associated emissions 
reductions, particularly those focused on the space heating area source 
sector. Specifically, the implementation of specific measures designed 
to reduce emissions from solid fuel-fired burning devices impacts 
nearly all other area-source controls measures. For example, the wood 
stove change out program removes wood stoves from the emissions 
inventory. This reduces direct PM2.5 emissions, but also 
impacts the emissions reductions achieved by the Solid Fuel-Burning 
Appliance Curtailment Program and dry wood requirements.
    Alaska could achieve more wood stove change-outs than it projects 
in a milestone year and, thus, achieve more emissions reductions 
attributable to that measure. However, that measure, by its nature, 
changes the makeup of the remaining wood stove users and their 
collective compliance with dry wood requirements and the curtailment 
program. Thus, there could be an instance where Alaska overperforms on 
one wood stove control measure, and that overperformance causes an 
underperformance on one or more other similar measures, but that 
collectively the measures achieve RFP.
    Relatedly, the wood stove change out program has the potential to 
moderate the benefits of measures designed to reduce SO2 
emissions by increasing the number of residences using oil fuel-fired 
heating devices. Comparing emissions reductions achieved to projected 
emissions reductions as the milestone metric allows Alaska to take into 
consideration these complex interactions and ultimately provides a more 
meaningful assessment of whether Alaska's plan is achieving RFP.
    In addition to the emissions reduction metric, the Fairbanks 
Revised 189(d) Plan includes several other objective metrics for RFP, 
including the number of wood stoves changed out, compliance percentage 
for tracking the progress of the solid-fuel burning device change out 
program, and percent implementation as metrics for the fuel sulfur 
content shift mandate, dry wood requirements, mandatory wood device 
removal, and more stringent no other adequate source of heat 
requirements.
    Alaska has demonstrated its ability to include emissions reduction 
statistics in its quantitative milestone reports. On March 29, 2024, 
Alaska submitted its quantitative milestone report for quantitative 
milestone year 2023 (``2023 QM Report''). The EPA determined the 2023 
QM Report was adequate on November 14, 2024. Both the 2023 QM Report 
and the EPA's adequacy determination are included in the docket for 
this action.
    The 2023 QM Report included a certification from the Governor's 
designee that the control strategy in the Fairbanks Revised 189(d) Plan 
is being implemented consistent with the RFP provisions in the 
Fairbanks Revised 189(d) Plan. The 2023 QM Report also included 
calculations and associated technical support for emissions reductions 
attributable to the measures in the control strategy. The report 
compared emissions reductions achieved to date to those projected based 
on the control measure phase-in schedule. The report also included, for 
example, the number of wood stoves changed out as of 2023 as well as 
the basis for implementation percentages and compliance rates for each 
control measure. Finally, the 2023 QM Report included a discussion as 
to whether the area will attain the PM2.5 NAAQS by 2027. 
Therefore, the EPA proposes to approve the Fairbanks Revised 189(d) 
Plan as meeting the quantitative milestone requirements of CAA section 
189(c)(1) and 40 CFR 51.1013.

[[Page 1623]]

G. Contingency Measures

1. Statutory and Regulatory Requirements Regarding the Contingency 
Measures
    Under CAA section 172(c)(9), states required to make an attainment 
plan SIP submission must include contingency measures to be implemented 
if the area fails to meet RFP or fails to attain the NAAQS by the 
applicable attainment date. Under the PM2.5 SIP Requirements 
Rule, states must include contingency measures that the state will 
implement following a determination by the EPA that the state has 
failed: (1) to meet any RFP requirement in the approved SIP; (2) to 
meet any QM in the approved SIP; (3) to submit a required QM report; or 
(4) to attain the applicable PM2.5 NAAQS by the applicable 
attainment date.\182\
---------------------------------------------------------------------------

    \182\ 40 CFR 51.1014(a).
---------------------------------------------------------------------------

    In accordance with the statute, contingency measures must be fully 
adopted rules or control measures that are ready to be implemented upon 
the EPA determination of a failure of any of the four types specified 
by statute and regulation for purposes of the PM2.5 NAAQS at 
issue.\183\ The contingency measures must be included in the state's 
SIP and explicitly provide that they will take effect in the case of 
any such finding of failure, without further significant action by the 
State or the EPA. In general, the EPA expects all actions needed to 
effect full implementation of the measures to occur within 60 days 
after the EPA notifies the state of a failure to meet RFP or of a 
failure to attain.\184\ The EPA has historically recommended that the 
additional emissions reductions from the contingency measures should be 
achieved within a year of the triggering event.\185\ The EPA has 
recently revised its guidance concerning the period of time during 
which contingency measures should provide emissions reductions, and now 
recommends that it may be appropriate for contingency measures to 
achieve emissions reductions within two years under certain 
circumstances.\186\ The purpose of contingency measures is to continue 
progress toward attainment, as the state develops and submits, and the 
EPA acts on, a SIP submission to address the underlying deficiency.
---------------------------------------------------------------------------

    \183\ 81 FR 58010, August 24, 2016, at p. 58066; see also 
Addendum to the General Preamble for the Implementation of Title I 
of the Clean Air Act Amendments of 1990, 59 FR 41998, August 16, 
1994, at 42015 (``General Preamble Addendum'').
    \184\ 81 FR 58010, August 24, 2016, at p. 58066; see also 
General Preamble at pp. 13512, 13543-13544, and General Preamble 
Addendum, at pp. 42014-42015.
    \185\ General Preamble, at p. 13511.
    \186\ ``Guidance on the Preparation of State Implementation 
Plans Provisions that Address the Nonattainment Area Contingency 
Measure Requirements for Ozone and Particulate Matter,'' Joseph 
Goffman, U.S. Environmental Protection Agency, Assistant 
Administrator, Office of Air and Radiation, December 3, 2024.
---------------------------------------------------------------------------

    Neither the CAA nor the EPA's implementing regulations establish a 
specific level of emissions reductions that implementation of 
contingency measures must achieve, but the EPA has historically 
recommended that contingency measures should provide for emissions 
reductions equivalent to approximately one year of reductions needed 
for RFP in the nonattainment area.\187\ For PM2.5 NAAQS SIP 
planning purposes, prior to issuing the recent contingency measure 
guidance, the EPA has recommended that RFP should be calculated as the 
overall level of reductions needed to demonstrate attainment divided by 
the number of years from the base year to the attainment year.\188\ As 
part of the attainment plan SIP submission, the EPA expects states to 
explain the amount of anticipated emissions reductions that the 
contingency measures will achieve. In the event that a state is unable 
to identify and adopt contingency measures that will provide for 
approximately one year's worth of emissions reductions, then the EPA 
recommends that the state provide a reasoned justification why the 
smaller amount of emissions reductions is appropriate.\189\ As further 
described below, the EPA revised and updated its guidance concerning 
the amount of emissions reductions that contingency measures should 
achieve and expanded its recommendations concerning how states may 
justify having contingency measures that achieve fewer reductions, in 
light of recent court decisions and the changed factual circumstances.
---------------------------------------------------------------------------

    \187\ 81 FR 58010, August 24, 2016, at p. 58066; see also 
General Preamble, at pp. 13511, 13543-13544, and General Preamble 
Addendum, at pp. 42014-42015.
    \188\ 81 FR 58010, August 24, 2016, at p. 58066.
    \189\ Id. at p. 58067.
---------------------------------------------------------------------------

    To satisfy the contingency measure requirements of 40 CFR 51.1014, 
the contingency measures adopted as part of a PM2.5 NAAQS 
attainment plan must consist of control measures for sources in the 
area that are not otherwise required to meet other attainment plan 
requirements (e.g., BACM or BACT requirements). By definition, 
contingency measures are measures that are over and above what a state 
must adopt and impose to meet RFP and to provide for attainment by the 
applicable attainment date. Contingency measures serve the purpose of 
providing additional emissions reductions during the period after a 
failure to meet RFP or failure to attain as the state prepares a new 
SIP submission to rectify the problem. Accordingly, contingency 
measures must provide such additional emissions reductions during an 
appropriate period and must specify the timeframe by which their 
requirements would become effective following any of the EPA 
determinations specified in 40 CFR 51.1014(a).
    To comply with CAA section 172(c)(9), contingency measures must be 
both conditional and prospective, so that they will go into effect and 
achieve emissions reductions only in the event of a future triggering 
event such as a failure to meet RFP or a failure to attain. In the 2016 
Bahr v. EPA decision,\190\ the Ninth Circuit Court of Appeals held that 
CAA section 172(c)(9) does not allow EPA approval of already-
implemented control measures as contingency measures. Thus, already-
implemented measures cannot serve as contingency measures under CAA 
section 172(c)(9). For purposes of the PM2.5 NAAQS, a state 
must develop, adopt, and submit one or more contingency measures to be 
triggered upon a failure to meet any RFP requirement, failure to meet a 
quantitative milestone requirement, or failure to attain the NAAQS by 
the applicable attainment date, regardless of the extent to which 
already implemented measures would achieve surplus emissions reductions 
beyond those necessary to meet RFP or quantitative milestone 
requirements and beyond those predicted to achieve attainment of the 
NAAQS.
---------------------------------------------------------------------------

    \190\ Bahr v. EPA, 836 F.3d 1218, 1235-1237 (9th Cir. 2016). See 
also Sierra Club v. EPA, 21 F.4th 815, 827-28 (D.C. Cir. 2021).
---------------------------------------------------------------------------

    In another recent decision concerning contingency measures for the 
ozone NAAQS, the Ninth Circuit Court of Appeals held that the surplus 
emissions reductions from already-implemented measures cannot be relied 
upon to justify the approval of a contingency measure that would 
achieve far less than one year's worth of RFP as sufficient by itself 
to meet the contingency measure requirements of CAA sections 172(c)(9) 
and 182(c)(9) for the nonattainment area.\191\
---------------------------------------------------------------------------

    \191\ Assoc. of Irritated Residents v. EPA, 10 F.4th 937, 946-47 
(9th Cir. 2021) (``AIR v. EPA'' or ``AIR'').
---------------------------------------------------------------------------

a. Revised Contingency Measure Guidance
    On December 3, 2024, the EPA issued new guidance addressing the 
contingency measures requirement of CAA section 172(c)(9), herein 
referred to as the ``Contingency Measure

[[Page 1624]]

Guidance.'' \192\ The principal differences between the latest 
Contingency Measure Guidance and prior guidance on contingency measures 
relate to the EPA's recommendations concerning the specific amount of 
emissions reductions that implementation of contingency measures should 
achieve and to the timing for when the emissions reductions from the 
contingency measures should occur. The Contingency Measure Guidance 
also provides recommended procedures for developing a demonstration, if 
applicable, that the area lacks sufficient feasible measures to achieve 
one year's worth of reductions, building on existing guidance that the 
state may provide a reasoned justification why the smaller amount of 
emissions reductions is appropriate.\193\
---------------------------------------------------------------------------

    \192\ ``Guidance on the Preparation of State Implementation 
Plans Provisions that Address the Nonattainment Area Contingency 
Measure Requirements for Ozone and Particulate Matter,'' Joseph 
Goffman, U.S. Environmental Protection Agency, Assistant 
Administrator, Office of Air and Radiation, December 3, 2024.
    \193\ See 81 FR 58010, Aug. 24, 2016, at p. 58067.
---------------------------------------------------------------------------

    The EPA has historically recommended that contingency measures 
should achieve approximately one year's worth of RFP, calculated based 
upon the initial emissions inventory of the attainment plan for the 
area in question. As explained in the updated guidance, however, the 
EPA is revising its interpretation of the requirements of CAA section 
172(c)(9). Under the Contingency Measure Guidance, the EPA recommends 
that the amount of emissions reductions that contingency measures 
should achieve should be one year's worth of ``progress,'' as opposed 
to one year's worth of RFP.\194\ One year's worth of ``progress'' is 
calculated by determining the average annual reductions between the 
base year emissions inventory and the projected attainment year 
emissions inventory, determining what percentage of the base year 
emissions inventory this amount represents, then applying that 
percentage to the projected attainment year emissions inventory to 
determine the amount of reductions appropriate from contingency 
measures to ensure ongoing progress if the measures are triggered.
---------------------------------------------------------------------------

    \194\ Contingency Measure Guidance, at p. 23.
---------------------------------------------------------------------------

    With respect to the time period that reductions from contingency 
measures should occur, the EPA previously recommended that contingency 
measures take effect within 60 days of being triggered, and that the 
resulting emissions reductions generally occur within one year of the 
triggering event. Under the Contingency Measure Guidance, in instances 
where there are insufficient contingency measures available to achieve 
the recommended amount of emissions reductions within one year of the 
triggering event, the EPA is recommending that contingency measures 
that provide reductions within two years of the triggering event would 
be appropriate to consider towards achieving the recommended amount of 
emissions reductions.\195\ The Contingency Measure Guidance does not 
alter the 60-day recommendation for the contingency measures to take 
initial effect.\196\
---------------------------------------------------------------------------

    \195\ Contingency Measure Guidance, at p. 46
    \196\ Id.
---------------------------------------------------------------------------

    If, after adequately evaluating additional control measures, the 
state is unable to identify contingency measures that would provide a 
sufficient amount of emissions reductions, the EPA recommends that the 
state provide an analysis to establish that there are no additional 
feasible contingency measures. The EPA has recommended this approach 
for attainment plans for the PM2.5 NAAQS since promulgating 
the PM2.5 SIP Requirements Rule.\197\ In the Contingency 
Measure Guidance, the EPA provides additional guidance to states for 
establishing that there are no additional feasible contingency 
measures. The EPA recommends that the state should provide a reasoned 
justification that explains and documents how it has evaluated all 
existing and potential control measures relevant to the appropriate 
source categories and pollutants in the nonattainment area, and has 
reached reasonable conclusions regarding whether such measures are 
feasible as contingency measures.\198\
---------------------------------------------------------------------------

    \197\ See 81 FR 58010, Aug. 24, 2016, at p. 58067.
    \198\ Contingency Measure Guidance, at p. 33.
---------------------------------------------------------------------------

    As explained in the Contingency Measure Guidance, while the EPA 
notes that CAA section 172(c)(9) and section 182(c)(9) do not 
explicitly provide for consideration of whether specific measures are 
feasible, the Agency believes that the best reading of these provisions 
is that they do not require states to adopt contingency measures 
regardless of any technological or cost constraints whatsoever.\199\ 
Thus, the EPA views the contingency measure requirements as not to 
require air agencies to adopt and impose infeasible measures. The 
statutory provisions applicable to other nonattainment area plan 
control measure requirements, including RACM/RACT (for ozone and PM), 
BACM/BACT (for PM), and MSM (for PM), allow air agencies to exclude 
certain control measures that are deemed unreasonable or infeasible 
(depending on the requirement). For example, the MSM provision in CAA 
section 188(e) requires plans to include ``the most stringent measures 
that are included in the implementation plan of any state or are 
achieved in practice in any state, and can feasibly be implemented in 
the area.'' The EPA concludes that Congress similarly did not expect 
air agencies to satisfy the contingency measure requirement with 
infeasible measures. Thus, the EPA anticipates that a demonstrated lack 
of feasible measures would be a reasoned justification for adopting 
contingency measures that only achieve a lesser amount of emissions 
reductions.\200\
---------------------------------------------------------------------------

    \199\ Id.
    \200\ Contingency Measure Guidance, at p. 34.
---------------------------------------------------------------------------

2. Summary of the EPA's Prior Action Regarding the Contingency Measures
    In the Fairbanks Serious Plan, Alaska submitted revisions to 18 AAC 
50.077(n) that included two contingency measures purporting to meet the 
requirements of CAA section 172(c)(9) and 40 CFR 51.1014. The first 
measure requires owners of older EPA-certified wood fired heating 
devices with an emission rating above 2.0 grams per hour (g/hr), 
manufactured 25 years prior to the effective date of an EPA finding 
that triggers this measure, to remove the device upon the sale of a 
property or by December 31, 2024, whichever is earlier. The second 
measure requires owners of EPA-certified devices that were manufactured 
less than 25 years prior to the EPA finding to remove the device prior 
to reaching 25 years from the date of manufacture. On September 24, 
2021, the EPA approved the submitted revisions to 18 AAC 50.077(n) as 
SIP-strengthening, but otherwise did not determine whether the 
revisions satisfied the contingency measure requirement of CAA section 
172(c)(9) and 40 CFR 51.1014.
    On September 2, 2020, the EPA issued a determination that the 
Fairbanks PM2.5 Nonattainment Area failed to attain the 2006 
24-hour NAAQS by the Serious area attainment date.\201\ This action 
triggered the contingency measures included in the Fairbanks Serious 
Plan at 18 AAC 50.077(n).
---------------------------------------------------------------------------

    \201\ 85 FR 54509, September 2, 2020, at pp. 54509-10.
---------------------------------------------------------------------------

    In the initial Fairbanks 189(d) Plan, Alaska: (1) retained the 
revisions to 18 AAC 50.077(n); (2) submitted a revision to state 
regulations at 18 AAC 50.030(c), to act as a central trigger mechanism 
for all contingency measures contained in Alaska's nonattainment 
plans,\202\ and (3)

[[Page 1625]]

included an additional contingency measure, as a revision to State Air 
Quality Control Plan, Vol. II, section III.D.7.12 (Fairbanks Emergency 
Episode Plan) that, if triggered, lowers the wood stove curtailment 
Stage 2 alert threshold from 30 [micro]g/m\3\ to 25 [micro]g/m\3\.
---------------------------------------------------------------------------

    \202\ ``Contingency measures in nonattainment and maintenance 
areas identified in 18 AAC 50.015(b), (d), and (e) must be 
implemented as described in the State Air Quality Control Plan for 
an area upon. . .the effective date of an EPA finding that the area 
failed (i) to attain the applicable NAAQS by the applicable 
attainment date; (ii) to meet a quantitative milestone; (iii) to 
submit a required quantitative milestone report; or (iv) to meet a 
reasonable further progress requirement.''
---------------------------------------------------------------------------

    On January 10, 2023, the EPA approved the submitted revisions to 18 
AAC 50.030(c) as consistent with the triggering events in 40 CFR 
51.1014. The EPA also approved as SIP-strengthening the submitted 
revisions to the Fairbanks Emergency Episode Plan regarding the wood 
stove curtailment thresholds. However, the EPA determined that the 
revisions to 18 AAC 50.077(n) did not meet contingency measures 
requirements because they were already triggered and implemented.
    With respect to the revision in the Fairbanks Emergency Episode 
Plan, the EPA determined that this measure alone is insufficient to 
meet contingency measures requirements, and Alaska did not provide a 
reasoned justification for why the state could not adopt additional 
contingency measures. Thus, the EPA disapproved the Fairbanks Serious 
Plan and initial Fairbanks 189(d) Plan with respect to the contingency 
measures element. The State is addressing this prior disapproval for 
the contingency measures element by submitting new provisions intended 
to meet the requirement in the Fairbanks Revised 189(d) Plan.
3. Summary of the State's Submission Regarding the Contingency Measures
    In the Fairbanks Revised 189(d) Plan, Alaska includes: (1) 
calculations of one year's worth of progress and RFP metrics; (2) an 
evaluation of potential contingency measures; (3) three contingency 
measures purporting to meet the requirements of CAA section 172(c)(9) 
and 40 CFR 51.1014; and (4) an evaluation of whether the contingency 
measures achieve sufficient emissions reductions.
a. Alaska's Calculation of One Year's Worth of Progress
    Alaska used the one year's worth of progress metric to demonstrate 
that its contingency measures achieve sufficient emissions 
reductions.\203\ According to the Fairbanks Revised 189(d) Plan, the 
one year's worth of progress target is 0.102 tons per episode day for 
direct PM2.5 emissions and 0.115 tons per episode day for 
SO2 emissions. Alaska also calculated the one year's worth 
of RFP target for direct PM2.5 and SO2 as 0.172 
tons per episode day and 0.122 tons per episode day, respectively.\204\
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    \203\ State Air Quality Control Plan, Vol. II, section 
III.D.7.11.2.1 (adopted November 5, 2024).
    \204\ Id. at section III.D.7.10, Table 7.10-8.
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b. Alaska's Identification and Evaluation of Contingency Measures
    Alaska evaluated 25 potential measures as contingency 
measures.\205\ Alaska evaluated measures to reduce SO2 
emissions and direct PM2.5 emissions. Alaska determined that 
there were no NH3 control measures that could serve as 
contingency measures.\206\ With respect to SO2 emissions, 
Alaska evaluated requiring the use of ULSD heating oil (i.e., a 15 
parts per million sulfur content fuel oil requirement). According to 
Alaska, the ULSD mandate would significantly reduce SO2 
emissions from the residential space heating source category. However, 
Alaska determined that the ULSD mandate could not achieve emissions 
reductions until year three of implementation and also posed 
technological feasibility concerns.\207\
---------------------------------------------------------------------------

    \205\ Id. at section III.D.7.11.2.2.
    \206\ Id. at section III.D.7.11.3.3.8.
    \207\ Id. at section III.D.7.11.3.3.1.1.
---------------------------------------------------------------------------

    Alaska also identified major stationary source SO2 
controls, aircraft SO2 controls, residential fuel oil 
boilers repair and replacement requirements as potential measures. 
Alaska determined that, based on the major stationary source 
SO2 precursor demonstration, SO2 controls on 
these sources would achieve negligible reductions in sulfate formation 
in the nonattainment area.\208\ Similarly, Alaska determined that 
requiring residents to replace or upgrade their fuel oil boilers would 
result in negligible SO2 emissions reductions.\209\ With 
respect to aircraft, Alaska explained that the State does not have 
authority to regulate fuel sulfur content for commercial aircraft. 
Thus, Alaska determined that there were no technologically feasible 
contingency measures for SO2.
---------------------------------------------------------------------------

    \208\ Id. at section III.D.7.11.3.3.1
    \209\ Id. at section III.D.7.11.3.3.1.3. According to the 
Fairbanks Revised 189(d) Plan, requiring residents to repair their 
fuel oil boilers would achieve at most 0.001 tons per day of 
SO2 emissions reductions. Requiring replacement of fuel 
oil boilers would achieve at most 0.006 tons per day of 
SO2 emissions reductions.
---------------------------------------------------------------------------

    Alaska also evaluated several potential contingency measures 
designed to reduce emissions of direct PM2.5. Specifically, 
Alaska evaluated enhancements to the existing curtailment program, 
enhancements to the existing wood device removal program, used oil 
burning restrictions, vehicle idling restrictions, making existing 
control measures more stringent, and various economic incentive 
programs suggested by commenters.\210\ Alaska ultimately determined 
that enhancing the existing curtailment program and existing wood 
device removal program were the only technologically feasible measures 
that would achieve more than negligible emissions reductions.
---------------------------------------------------------------------------

    \210\ Id. at section III.D.7.11.3.3.
---------------------------------------------------------------------------

    Alaska determined that prohibiting small ``pot burners'' and used 
oil burners would achieve negligible emissions reductions.\211\ 
According to the Fairbanks Revised 189(d) Plan, prohibiting small pot 
burners would achieve emissions reductions of 0.002 tons per episode 
day of direct PM2.5.\212\ Likewise, prohibiting used oil 
burners would achieve less than 0.0001 tons per episode day of direct 
PM2.5 emissions reductions.\213\ Similarly, Alaska 
determined that imposing vehicle idling restrictions would achieve 
0.002 tons per episode day of direct PM2.5 emissions 
reductions.
---------------------------------------------------------------------------

    \211\ Id. at section III.D.7.11.3.3.3.
    \212\ Id.
    \213\ Id.
---------------------------------------------------------------------------

    Alaska also evaluated adopting a 1.0 grams per hour PM emissions 
standard for new solid fuel-fired heating devices, similar to the 
measure implemented by Missoula, Montana.\214\ Alaska determined that 
this measure would achieve emissions reductions through attrition 
(phase-out of old stoves) and would not achieve significant emissions 
reductions in the aggregate given Alaska's already stringent 
restrictions on new wood stoves.\215\ Alaska also noted that the 
measure effectively restricts new solid-fuel burning devices to pellet-
fuel fired stoves. Alaska explained that pellet stoves require 
electricity to operate. According to Alaska, Fairbanks experiences 
frequent power outages during the winter months and residents must have 
a reliable source of heat during these periods. According to Alaska, 
this renders the measure technologically infeasible as a contingency 
measure.
---------------------------------------------------------------------------

    \214\ Id. at section III.D.7.11.3.3.2.
    \215\ Id.
---------------------------------------------------------------------------

    In addition, Alaska evaluated reducing the allowable moisture 
content in commercial dry wood.\216\ Under Alaska's current 
regulations, all commercial dry wood must have a moisture content of 20 
percent or less.\217\ Alaska determined that reducing the moisture 
content percentage to 15

[[Page 1626]]

would reduce PM2.5 emissions by 0.011 tons per episode day, 
while reducing the moisture percentage to 10 would reduce 
PM2.5 emissions by 0.022 tons per episode day. However, 
Alaska determined that achieving these emissions reductions within two 
years of a triggering event is not technologically feasible due to 
infrastructure constraints.\218\ According to Alaska, there is a single 
dry wood kiln in Fairbanks that supplies 31 percent of the commercial 
dry wood in the area. Requiring the kiln to achieve lower wood moisture 
content would require longer dry times, which would restrict the 
availability of dry wood in the area unless the kiln expanded capacity.
---------------------------------------------------------------------------

    \216\ Id. at section III.D.7.11.3.3.5.
    \217\ 18 AAC 50.076(g).
    \218\ State Air Quality Control Plan, Vol. II, section 
III.D.7.11.3.3.5.
---------------------------------------------------------------------------

    Alaska also evaluated granting citation authority to the Alaska 
Department of Environmental Conservation and increasing civil penalties 
for SIP violations as potential contingency measures.\219\ Alaska 
determined that neither measure would improve compliance or achieve 
emissions reductions.\220\ Alaska explained that it has broad and 
efficient state judicial authority to enforce violations of the SIP. 
Alaska included a discussion of its process for enforcing SIP 
violations. Alaska also explained that its civil penalty authority 
under Alaska Statute 46.03.760(e) does not set a maximum penalty for 
SIP violations.\221\
---------------------------------------------------------------------------

    \219\ Id. at section III.D.7.11.3.3.6; Id. at section 
III.D.7.11.3.3.4.
    \220\ Id.
    \221\ Id. at section III.D.7.11.3.3.6.
---------------------------------------------------------------------------

    Finally, Alaska evaluated whether several economic incentive 
programs suggested by commenters could satisfy contingency measure 
requirements.\222\ These included subsidizing the cost of ULSD, 
subsidizing natural gas, and various electricity cost subsidy 
programs.\223\ Alaska determined that each of these programs would not 
be enforceable contingency measures. Alaska also noted that 
implementing the programs would require more than minimal further 
effort on the part of the state.\224\ Therefore, Alaska concluded that 
these economic incentive programs would not meet the legal requirements 
for contingency measures.
---------------------------------------------------------------------------

    \222\ Id. at section III.D.7.11.3.3.7.
    \223\ Id.
    \224\ Id.
---------------------------------------------------------------------------

c. Alaska's Contingency Measures Included in the Fairbanks Revised 
189(d) Plan
    Based on the analysis discussed in the preceding paragraphs, Alaska 
concluded that the only technologically feasible contingency measures 
were enhancing the solid fuel burning device curtailment and removal 
programs. Therefore, in the Fairbanks Revised 189(d) Plan, the State 
includes three measures intended to meet the contingency measures 
requirements: (1) lower alert levels under the Solid Fuel-Burning 
Appliance Curtailment Program; (2) an enforceable commitment to 
increase the staff hours dedicated to implementing the Solid Fuel-
Burning Appliance Curtailment Program; and (3) an enforceable 
commitment to increase staff hours dedicated to compliance and 
enforcement with the state regulations requiring replacement of older 
wood stoves by December 31, 2024.\225\
---------------------------------------------------------------------------

    \225\ 18 AAC 50.075(e); State Air Quality Control Plan, Vol. II, 
section III.D.7.11.4.
---------------------------------------------------------------------------

    Alaska's current EPA-approved Solid Fuel-Burning Appliance 
Curtailment Program includes two stages. Alaska calls a Stage 1 burn 
ban when Alaska projects ambient PM2.5 concentrations to be 
at or above 20 [micro]g/m\3\. Under a Stage 1 burn ban, individuals may 
only operate their solid fuel-burning device if the individual has an 
Alaska-approved ``no other adequate source of heat'' (NOASH) waiver or 
an Alaska-approved solid fuel-burning device that meets specific stage 
1 waiver age and emission rate criteria.\226\ Under the current 
curtailment program, Alaska calls a Stage 2 burn ban when the state 
projects ambient PM2.5 concentrations to exceed 30 [micro]g/
m\3\. Under a Stage 2 burn ban, individuals may only operate their 
solid fuel burning device if they have an Alaska-approved NOASH 
waiver.\227\
---------------------------------------------------------------------------

    \226\ Id.
    \227\ Id.
---------------------------------------------------------------------------

    As the first intended contingency measure, the State adopted 
revisions to the Fairbanks Emergency Episode Plan that would reduce the 
alert levels under the Solid Fuel-Burning Appliance Curtailment 
Program.\228\ Upon a triggering event, such as failure to attain or 
failure to meet a QM, the Stage 1 alert level will be lowered to 15 
[micro]g/m\3\ and the Stage 2 alert level will be lowered to 20 
[micro]g/m\3\.\229\ The State anticipates that lowering these alert 
levels would result in Alaska calling burn bans more frequently and for 
longer durations, thus lowering the emissions from the solid fuel 
burning device source category.\230\ Alaska projected this first 
contingency measure will result in emissions reductions of 0.086 tons 
per day PM2.5 but increase SO2 emissions by 0.047 
tons per day.
---------------------------------------------------------------------------

    \228\ State Air Quality Control Plan, Vol. II, section 
III.D.7.12.2.
    \229\ Id. See also State Air Quality Control Plan, Vol. II, 
section III.D.7.12, Table 7.12-1.
    \230\ State Air Quality Control Plan, Vol. II, section 
III.D.7.11.3.1.
---------------------------------------------------------------------------

    As a second intended contingency measure in the Fairbanks Revised 
189(d) Plan, the State submitted an enforceable commitment to increase 
the Alaska Department of Environmental Conservation staff hours 
dedicated to the compliance and enforcement of the Solid Fuel-Burning 
Appliance Curtailment Program to 2,800 hours per year, within 60 days 
of any triggering event.\231\ This would be an increase from the 
current 2,200 hours per year.\232\ Under the current allocation of 
staff hours, Alaska achieved 38 percent compliance with the curtailment 
program.\233\ Alaska projected that with the additional staff hours, 
the compliance rate would increase to 65 percent.\234\ Alaska committed 
to maintain the increased allocation of staff hours, unless or until 
the state could later relax the measure through a SIP revision.\235\ 
Alaska further committed to publishing an annual report that includes 
the staff hours dedicated to compliance and enforcement of the Solid 
Fuel-Burning Appliance Curtailment Program and the results of the 
Alaska Department of Environmental Conservation's annual assessments of 
the compliance rate.\236\
---------------------------------------------------------------------------

    \231\ 18 AAC 50.075(e); State Air Quality Control Plan, Vol. II, 
section III.D.7.12. See State Air Quality Control Plan, Vol. II, 
section III.D.7.11.4.3.
    \232\ State Air Quality Control Plan, Vol. II, section 
III.D.7.11.4.1.
    \233\ Id.; See also State Air Quality Control Plan, Vol. II, 
section III.D.7.10.3.2.
    \234\ Id. at section III.D.7.11.4.1.
    \235\ Id. at section III.D.7.11.4.3.
    \236\ Id.
---------------------------------------------------------------------------

    As the third intended contingency measure, the State submitted a 
second enforceable commitment to dedicate 300 staff hours to compliance 
and enforcement with the SIP-approved rules requiring replacement of 
older wood stoves (18 AAC 50.077(l-n)).\237\ Alaska projects this 
staffing level would increase the compliance rate from 30 percent to 45 
percent.\238\ Alaska committed to maintaining the allocation of 
staffing hours unless or until the state can relax the measure through 
a SIP revision.\239\ Alaska further committed to publishing an annual 
report that includes the staff hours dedicated to compliance and 
enforcement with the regulations mandating replacement of older wood 
stoves.\240\
---------------------------------------------------------------------------

    \237\ Id.
    \238\ Id. at section III.D.7.11.4.2.
    \239\ Id. at section III.D.7.11.4.3.
    \240\ Id.

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[[Page 1627]]

d. Emissions Reductions From Alaska's Contingency Measures
    Alaska projected that these three contingency measures would 
achieve emissions reductions of 0.151 tons per episode day of direct 
PM2.5 emissions (0.142 tons per day when accounting for some 
overlap) and increase SO2 emissions by 0.038 tons per 
episode day. As stated in the preceding paragraphs, Alaska proposed to 
use the one year's worth of progress metric for contingency measures. 
According to the Fairbanks Revised 189(d) Plan, the one year's worth of 
progress target is 0.102 tons per episode day for direct 
PM2.5 and 0.115 tons per episode day for SO2.
    Alaska purported to justify the increase in SO2 
emissions with the surplus emissions reductions of direct 
PM2.5 emissions through ``inter-pollutant trading.'' \241\ 
Alaska developed a 5:1 ratio to compare reductions of direct 
PM2.5 emissions to reductions of SO2 emissions. 
For the purposes of developing the ratio, Alaska conservatively 
estimated that SO2 emissions contribute 20 percent of 
ambient PM2.5 levels in the area.\242\ Thus, Alaska 
calculated that achieving an additional 0.023 tons per episode day 
(0.125 tons per episode day total) of direct PM2.5 emissions 
would achieve the required one year's worth of attainment for both 
direct PM2.5 and SO2 emissions.\243\ Because 
Alaska's contingency measures would achieve 0.151 tons per episode day 
of direct PM2.5 emissions, Alaska stated that its 
contingency measures would achieve sufficient emissions 
reductions.\244\
---------------------------------------------------------------------------

    \241\ Id. at section III.D.7.11.2.1.
    \242\ Id.
    \243\ Id.
    \244\ Id.
---------------------------------------------------------------------------

    Alaska also compared the projected emissions reductions from its 
contingency measures to the one year's worth of RFP metric. Alaska 
calculated that the one year's worth of RFP target for direct 
PM2.5 and SO2 emissions as 0.172 tons per episode 
day and 0.122 tons per episode day respectively.\245\ The State 
acknowledged that its contingency measures would not achieve emissions 
reductions equivalent to one year's worth of RFP even taking into 
consideration inter-pollutant trading.\246\
---------------------------------------------------------------------------

    \245\ Id. at section III.D.7.10, Table 7.10-8.
    \246\ Id. at section III.D.7.10.3.4.
---------------------------------------------------------------------------

4. The EPA's Evaluation and Proposed Action
    The EPA has reviewed the three measures that the State included in 
the Fairbanks Revised 189(d) Plan to meet the contingency measures 
requirement for the 2006 24-hour PM2.5 NAAQS. For the 
reasons explained in the following sections and the accompanying TSD, 
the EPA: (i) proposes to approve one of the State's submitted measures 
as a contingency measure; (ii) proposes to approve the other two 
measures as SIP-strengthening; (iii) proposes to find that the State 
has provided an adequate reasoned justification that no other 
contingency measures are feasible; and (iv) proposes to approve the 
Fairbanks Revised 189(d) Plan as meeting the contingency measure 
requirements in CAA Section 179(c)(9) and 40 CFR 51.1014(a).
a. Alaska's Calculation of One Year's Worth of Progress
    Alaska proposed to use the one year's worth of progress metric to 
measure the sufficiency of its contingency measures. The EPA proposes 
to determine this is an appropriate metric. As discussed above, CAA 
section 172(c)(9) does not specify the amount of emissions reductions 
contingency measures must achieve. The EPA's recent revised guidance 
explains its view that one year's worth of progress approach is 
consistent with the primary objective of attaining the NAAQS.
    This approach takes into account the declining emissions 
inventories between the base year and attainment year. The EPA expects 
that Alaska's control strategy in the Fairbanks Revised 189(d) Plan 
will achieve projected emissions reductions prior to any triggering 
event. Specifically, public participation in the wood stove change out 
program should continue given the mandatory change out requirements in 
18 AAC 50.077(l)-(n), along with the EPA grant funding through the 
Targeted Airshed Grant program. Moreover, the continued phase-in of 
diesel no. 1 fuel oil in place of diesel no. 2 fuel oil will reduce 
SO2 emissions.
b. Alaska's Identification and Evaluation of Contingency Measures
    As summarized in section II.G.3 of this preamble, Alaska evaluated 
several control measures that could serve as contingency measures to 
reduce emissions of the relevant pollutants from the relevant sources. 
The EPA has reviewed the State's identification and evaluation of 
potential contingency measures. The EPA's detailed review is included 
in a Technical Support Document included in the docket for this 
action.\247\ For the reasons stated in the following paragraphs, as 
well as in the Technical Support Document, the EPA is proposing to 
determine that Alaska adequately identified and evaluated potential 
contingency measures.
---------------------------------------------------------------------------

    \247\ Jentgen, Matthew. (December 4, 2024). Contingency Measure 
assessment of available control measures in the Fairbanks Revised 
189(d) Plan. U.S. Environmental Protection Agency, Region 10, Air 
and Radiation Division, EPA-R10-OAR-2024-0595.
---------------------------------------------------------------------------

    In a prior action, the EPA approved comprehensive NOX 
and VOC precursor demonstrations submitted by Alaska. Therefore, these 
are not regulatory pollutants for purposes of the 2006 24-hour 
PM2.5 NAAQS in the Fairbanks PM2.5 Nonattainment 
Area. Accordingly, the State is not required to evaluate and adopt 
contingency measures for these pollutants.\248\ In this action, the EPA 
is proposing to approve an SO2 precursor demonstration for 
major stationary sources. If the EPA finalizes an approval of this 
precursor demonstration, then stationary sources that emit 
SO2 will not be subject to BACM/BACT. Accordingly, the State 
would not be required to evaluate and adopt contingency measures for 
SO2 emissions from such sources, but Alaska would still be 
required to evaluate and adopt SO2 emissions controls from 
other area and mobile sources.
---------------------------------------------------------------------------

    \248\ 88 FR 84626, December 5, 2023, at p. 84635.
---------------------------------------------------------------------------

    With respect to NH3, the EPA has previously approved 
Alaska's determination that there are no NH3 controls for 
major stationary sources in the nonattainment area.\249\ The EPA also 
previously approved as BACM for NH3 Alaska's suite of 
controls for direct PM2.5 on area sources.\250\ The EPA 
agrees with Alaska's determination that there are no additional 
NH3 controls that could serve as potential contingency 
measures.
---------------------------------------------------------------------------

    \249\ 88 FR 84626, December 5, 2023, at p. 84636.
    \250\ Id. at pp. 84,638-49.
---------------------------------------------------------------------------

    Alaska focused its evaluation of potential contingency measures on 
measures that could reduce direct PM2.5 emissions and 
SO2 emissions from areas sources and mobile sources. The EPA 
is proposing to approve the State's approach to identifying and 
adopting potential contingency measures for these specific pollutants 
and sources as part of its proposed approval of the contingency 
measures element of the Fairbanks Revised 189(d) Plan.
    With respect to contingency measures to reduce SO2 
emissions, the EPA proposes to approve Alaska's determinations that (1) 
mandating ULSD is not technologically feasible as a contingency measure 
because it would not achieve emissions reductions within two years of 
being triggered; (2) requiring residents to repair or replace their 
fuel oil boilers would achieve

[[Page 1628]]

negligible emissions reductions; and (3) regulating aircraft emissions 
is not viable as a contingency measure because of limitations on legal 
authority.
    Regarding mandating ULSD, the EPA agrees with the State that, if 
implemented, such a contingency measure could reduce SO2 
emissions from the residential home heating source category, which is 
the dominant contributor to sulfate formation in the nonattainment 
area. However, the EPA agrees with Alaska's determination that 
mandating USLD would not achieve emissions reductions until at least 
three years following the triggering event.\251\ This is due to the 
need to improve storage and distribution infrastructure in the area, 
the need to allow the distribution market to shift to new demands, and 
the time needed to phase out higher-sulfur fuels from existing storage 
vessels in the area.\252\ A contingency measure that required the use 
of ULSD fuel factually could not be implemented quickly following a 
triggering event, or achieve emissions reductions until several years 
following the triggering event. Thus, mandating ULSD as a contingency 
measure would not satisfy the key purpose of contingency measures of 
continuing progress towards attainment between the triggering event and 
submission of a revised plan. Based upon this analysis, the EPA agrees 
that a measure mandating sale and use of ULSD fuel in the Fairbanks 
PM2.5 Nonattainment Area is not viable as a contingency 
measure because of the time it would take to achieve emissions 
reductions.
---------------------------------------------------------------------------

    \251\ State Air Quality Control Plan, Vol. II, section 
III.D.7.11.3.3.1.1.
    \252\ Id.
---------------------------------------------------------------------------

    In addition, the EPA has reviewed Alaska's emissions reductions 
calculations, including for the fuel oil boiler measures, and 
determined Alaska's methodology is reasonable. Based on these 
calculations, the fuel oil boiler measures would achieve negligible 
emissions reductions. Regarding emissions from aircraft, states are 
prohibited under CAA section 233 from adopting more stringent standards 
than those set by the Federal Government.\253\ Therefore, the EPA 
agrees that none of these potential measures are viable as contingency 
measures.
---------------------------------------------------------------------------

    \253\ 42 U.S.C. 7573.
---------------------------------------------------------------------------

    Regarding potential contingency measures to control direct 
PM2.5 emissions, the EPA proposes to approve Alaska's 
determinations of: (1) measures that would only achieve negligible 
emissions reductions; (2) measures that are technologically infeasible 
as contingency measures because they would not achieve emissions 
reductions within two years of being triggered; and (3) other measures 
that are technologically infeasible due to infrastructure constraints 
and local conditions. The EPA agrees that prohibiting operation and 
sale of small pot burners, used oil burners, and restricting vehicle 
idling would achieve negligible emissions reductions. The EPA also 
agrees that granting citation authority to the Alaska Department of 
Environmental Conservation and increasing state penalties for SIP 
requirement violations would have negligible emissions benefits as a 
contingency measure.
    The EPA also reviewed Alaska's evaluation of a potential 
requirement that all new solid fuel-burning devices meet a 1.0 gram per 
hour PM2.5 emissions standard as a potential contingency 
measure. The EPA agrees that, in practice, the only wood heaters that 
can achieve this standard are pellet-fuel fired stoves and certain 
highly controlled cordwood stoves. The EPA also notes that, this 
measure has the potential to reduce direct PM2.5 emissions 
from the solid fuel-burning source category. However, the EPA agrees 
with Alaska's assessment that this requirement would necessarily be an 
attrition-based measure that only achieves emissions reductions as 
homeowners replace older stoves. In its prior action on the Fairbanks 
Serious Plan, the EPA disapproved a similar Alaska contingency measure 
mandating the removal of older certified wood stoves, in part because 
the measure would have achieved virtually no emissions reductions in 
the first year of implementation.\254\
---------------------------------------------------------------------------

    \254\ 88 FR 84626, December 5, 2023, at p. 84664.
---------------------------------------------------------------------------

    In addition, the EPA agrees that this measure is technologically 
infeasible as a contingency measure. In particular, as Alaska states in 
the Fairbanks Revised 189(d) Plan, pellet stoves require electricity to 
function, whereas cordwood stoves do not, and Fairbanks experiences 
power outages during the winter months. The EPA agrees that given the 
extremely cold temperatures residents experience, having a source of 
heat that does not rely on electricity remains a necessity. Based upon 
this analysis, the EPA agrees that a measure mandating that all new 
solid fuel-burning devices meet a 1.0 gram per hour PM2.5 
emissions standard in the Fairbanks area is not viable as a contingency 
measure because emissions reductions could not be achieved within two 
years and the measure is otherwise technologically infeasible.
    Regarding reducing the required moisture content for dry cordwood, 
the EPA notes that this measure has the potential to reduce emissions 
of direct PM2.5. Alaska estimated that a measure requiring 
all dry wood to meet a 10 percent moisture content would reduce 
PM2.5 emissions by 0.022 tons per episode day, which equates 
to 18 percent of one's years-worth of progress.\255\ However, the EPA 
agrees with Alaska's assessment that mandating a reduction in moisture 
content as a contingency measure would not be technologically feasible 
given the constraint on the dry wood supply in Fairbanks. In order to 
further reduce the moisture content of cordwood while satisfying 
consumer demand for commercial dry wood, additional kilns would need to 
be built in the Fairbanks area. This type of large capital project is 
unlikely to be accomplished quickly such that dry wood at less than 10 
percent moisture content could be reliably supplied to residents to 
achieve emissions reductions within two years of a triggering event.
---------------------------------------------------------------------------

    \255\ State Air Quality Control Plan, Vol. II, section 
III.D.7.11.3.3.5.
---------------------------------------------------------------------------

    Therefore, the EPA proposes to determine that, to the extent the 
contingency measures in the Fairbanks Revised 189(d) Plan fall short of 
the emissions reductions necessary for one year's worth of attainment, 
Alaska has provided an adequate reasoned justification for not adopting 
additional measures as contingency measures.
c. Evaluation of Submitted Contingency Measures
i. Lowered Alert Levels
    The submitted contingency measure lowering the alert levels for the 
Solid Fuel-Burning Appliance Curtailment Program is subject to Alaska's 
regulation at 18 AAC 50.030(c) that is consistent with the triggers in 
40 CFR 51.1014(a). The measure is thus conditional and prospective, as 
required by statute. This measure will take effect with minimal further 
effort from the State or the EPA. Neither Alaska nor the EPA will need 
to engage in any additional rulemaking or other significant action to 
implement the measure. Alaska already issues alerts through its 
preexisting program approved into the SIP. Thus, implementing the 
contingency measure will be ministerial, in terms of adjusting the 
curtailment alert thresholds.
    At the time of adoption and submission to the EPA, these 
contingency measure alert levels are not otherwise included in the 
control strategy to meet any other attainment plan requirements. This 
measure

[[Page 1629]]

addresses the largest source category of direct PM2.5 
emissions in the nonattainment area and is not otherwise included in 
the Fairbanks Revised 189(d) Plan control strategy. The EPA expects 
this continency measure would produce emissions benefits in addition to 
the projected emissions reductions under the control strategy and were 
not required to meet RFP or to attain by the attainment date.
    This contingency measure would go into effect once triggered by an 
EPA determination, as provided in 18 AAC 50.030(c). Alaska projected 
this first contingency measure will result in emissions reductions of 
0.086 tons per day PM2.5 but increase SO2 
emissions by 0.047 tons per day.\256\ This contingency measure 
represents 84 percent of one year's worth of progress for direct 
PM2.5 reductions, but, the increase in SO2 
emissions would not meet the one year's worth of progress metric for 
SO2.
---------------------------------------------------------------------------

    \256\ Applying Alaska's interpollutant trading mechanism, the 
combined emissions reductions for PM2.5 and 
SO2 are estimated to be 0.077 tons per day, representing 
62 percent of the one year's of interpollutant emissions reductions 
for PM2.5 and SO2. See State Air Quality 
Control Plan, Vol. II, section III.D.7.11.5.2; see also State Air 
Quality Control Plan, Vol. II, section III.D.7.11, Table 7.11-6.
---------------------------------------------------------------------------

    For the reasons provided in the preceding paragraphs, the EPA is 
proposing to determine that this measure meets the requirements for 
contingency measures in 40 CFR 51.1014 and CAA Section 172(c)(9). In 
section II.G.4.d of this preamble, we address whether approval of this 
contingency measure also supports approval of the overarching 
attainment plan contingency measures element of the Fairbanks Revised 
189(d) Plan for purposes of the 2006 24-hour PM2.5 NAAQS in 
the Fairbanks PM2.5 Nonattainment Area.
ii. Enforceable Commitments To Enhance Enforcement of the Solid Fuel-
Burning Appliance Curtailment Program and Removal of Wood Stoves
    These submitted measures take the form of enforceable commitments. 
According to Alaska, these measures would achieve surplus emissions 
reductions by increasing the compliance rate with the curtailment 
program from 38 percent to 65 percent and the wood stove removal 
measure from 30 percent to 45 percent. For the reasons stated in the 
following paragraphs, the EPA proposes to determine that these measures 
meet the CAA requirements for enforceable commitments. The EPA is 
further proposing to approve these commitments into the Alaska SIP as 
SIP-strengthening but not as contingency measures.
    First, Alaska's commitments meet the CAA's requirements for 
enforceable commitments. Under the CAA, an enforceable commitment must 
be: (1) a specific enforceable requirement, not merely an aspirational 
goal; and (2) enforceable as a practical matter (i.e., the public will 
have sufficient information to enforce the state's compliance with its 
commitment).\257\ In the submitted measures, Alaska committed to 
increase the allocation of annual staff hours by a specific number of 
hours dedicated to implementing and enforcing specific SIP measures. 
Thus, the commitment is sufficiently concrete and not merely an 
aspirational goal. Moreover, Alaska committed to publish a report of 
its compliance with these commitments. The report will not only include 
the number of hours dedicated to implementing and enforcing the 
specific measures, but also other compliance metrics such as number of 
warning letters and the number of wood stoves removed. Thus, the 
commitments are enforceable as a practical matter.
---------------------------------------------------------------------------

    \257\ See Comm. for a Better Arvin v. EPA, 786 F.3d 1169, 1181 
(9th Cir. 2015).
---------------------------------------------------------------------------

    In addition to the two criteria above, the EPA has assessed whether 
to approve an enforceable commitment based on consideration of the 
following three factors: (1) whether the commitment addresses a limited 
portion of the CAA requirement; (2) whether the state is capable of 
fulfilling its commitment; and (3) whether the commitment is for a 
reasonable and appropriate period of time.\258\ Regarding the first 
factor, in the past, states have relied on enforceable commitments as 
part of their overall control strategy to achieve the NAAQS.\259\ Thus, 
the EPA has typically assessed whether the emissions reductions 
attributable to the state's enforceable commitments are a limited 
portion of the emissions reductions necessary to achieve attainment or 
RFP.
---------------------------------------------------------------------------

    \258\ See 75 FR 74518, November 30, 2010, at pp. 74535-56; see 
also BCCA Appeal Grp. v. EPA, 355 F.3d 817, 840 (5th Cir. 2003).
    \259\ See, e.g., Approval of Air Quality Implementation Plans; 
California; South Coast; Attainment Plan for 1997 PM2.5 
Standards, 76 FR 69928, November 9, 2011, at p. 69941; Approval and 
Promulgation of Implementation Plans; Arizona--Maricopa County PM-10 
Nonattainment Area; Serious Area Plan for Attainment of the Annual 
PM-10 Standard, 65 FR 19964, April 13, 2000, at pp. 19983-19984.
---------------------------------------------------------------------------

    The EPA notes that Alaska structured its enforceable commitments as 
contingency measures. Thus, in the Fairbanks Revised 189(d) Plan, 
Alaska assessed the amount of emissions reductions that the commitments 
could achieve with respect to the one year's worth of progress and one 
year's worth of RFP metrics for contingency measures. Alaska determined 
that the emissions reductions attributable to the commitments are a 
small portion of the emissions reductions towards the recommended one 
year's worth of progress and one year's worth of RFP metrics for 
contingency measures, respectively.\260\ Alaska projected that 
emissions reductions attributable to the commitments will yield 38 
percent of the emissions reductions towards one-year's work of progress 
target.\261\
---------------------------------------------------------------------------

    \260\ The enhanced enforcement of the curtailment program is 
expected to yield 0.090 tons per day in PM2.5 emissions 
reductions and increase SO2 emissions by 0.038 tons per 
day (the increase in SO2 caused by the shift from wood 
burning to heating oil). See State Air Quality Control Plan, Vol. 
II, section III.D.7.11.5.1.
    \261\ State Air Quality Control Plan, Vol. II, section 
III.D.7.11.5.
---------------------------------------------------------------------------

    The EPA is proposing to determine that Alaska's enforceable 
commitments included in State Air Quality Control Plan, Vol. II, 
section III.D.7.11.2.1 address a limited portion of the CAA 
requirement. The EPA is not proposing to approve these commitments as 
contingency measures under CAA section 172(c)(9). If the EPA finalizes 
approval, these commitments will become part of Alaska's overall 
control strategy. Viewed in this light, Alaska would not rely on the 
enforceable commitments to achieve attainment or RFP.
    As to the second enforceable commitments factor, Alaska has 
demonstrated that it can fulfill its commitments. According to Alaska, 
the commitment to re-allocate staff hours is within the Alaska 
Department of Environmental Conservation Air Quality Division's 
existing budget and control. In the Fairbanks Revised 189(d) Plan, 
Alaska stated that it has the capacity to implement the reallocation of 
staffing hours it is making in the enforceable commitments and to 
maintain them indefinitely.\262\
---------------------------------------------------------------------------

    \262\ Id. at section III.D.7.11.6.
---------------------------------------------------------------------------

    Finally, the commitments are for a reasonable and appropriate 
period of time. For this factor, the EPA typically assesses the state's 
schedule for promulgating specific control measures to achieve the 
promised emissions reductions and whether the schedule comports with 
the RFP and attainment deadlines.\263\ Here, Alaska is not relying on 
the enforceable commitment to achieve RFP or attainment. Therefore, the 
EPA proposes to determine that this factor is not determinative with 
respect to Alaska's enforceable commitments.

[[Page 1630]]

Rather, Alaska structured the commitments as contingency measures 
triggered upon any of the EPA findings in 40 CFR 51.1014. Once 
triggered, Alaska committed to increasing staff hours within 60 days of 
the triggering event and maintain the staff hours unless and until the 
State could revise them through a SIP revision.\264\
---------------------------------------------------------------------------

    \263\ See, e.g., Approval of Air Quality Implementation Plans; 
California; South Coast; Attainment Plan for 1997 PM2.5 
Standards, 76 FR 69928, November 9, 2011, at p. 69941.
    \264\ State Air Quality Control Plan, Vol. II, section 
III.D.7.11.4.3.
---------------------------------------------------------------------------

    The EPA is proposing to approve the measures as SIP-strengthening 
but not as contingency measures under CAA section 172(c)(9) for the 
following reasons. The EPA acknowledges that the enforceable 
commitments meet many of the regulatory requirements in 40 CFR 51.1014. 
Specifically, the enforceable commitments are subject to Alaska's 
regulation 18 AAC 50.030(c) that is consistent with the triggers in 40 
CFR 51.1014(a). The Fairbanks Revised 189(d) Plan also includes a 
description of the specific trigger mechanisms for the commitment. The 
commitments also specify the timeframe within which they would become 
effective. Finally, Alaska is not relying on the emissions reductions 
that may occur as a result of increased compliance rates attributable 
to the enforceable commitments as part of its control strategy, to meet 
RFP requirements, or in its attainment demonstration.
    However, outside of the SO2 nonattainment context, the 
EPA has not considered increased enforcement of existing measures in 
the control strategy as ``implementation of specific measures'' that 
would ``take effect with minimal further action by the state of the 
EPA'' following a triggering event.\265\ The EPA has approved enhanced 
enforcement as satisfying the contingency measure requirement in the 
context of SO2 NAAQS nonattainment areas.\266\ This is for 
several reasons. First, the procedures and methods for quantifying and 
predicting SO2 concentrations are less uncertain than for 
other criteria pollutants, especially those that may result from 
secondary formation from multiple precursors, such as 
PM2.5.\267\ Second, the regulated sources in SO2 
nonattainment areas are typically one or a few major stationary sources 
that are the main cause of exceedances of the SO2 
NAAQS.\268\ Third, the control efficiencies for SO2 control 
measures are well understood and are less prone to uncertainty than for 
other criteria pollutants.\269\ Thus, the EPA has reasoned in the 
context of SO2 NAAQS nonattainment areas that if the 
nonattainment area fails to meet RFP or achieve attainment, then that 
failure is likely due to violations of the control strategy by the 
major stationary source regulated in the attainment plan --rather than 
an inadequacy of the control strategy.\270\ Hence, for purposes of the 
SO2 NAAQS, contingency measures comprised of a comprehensive 
enforcement program are sufficient.
---------------------------------------------------------------------------

    \265\ 40 CFR 51.1014(a). See Clean Air Plans; 2008 8-Hour Ozone 
Nonattainment Area Requirements; San Joaquin Valley, California, 84 
FR 11198, March 25, 2019, at pp. 11200, 11203.
    \266\ See Approval and Promulgation of Air Quality 
Implementation Plans; Michigan; Federal Implementation Plan for the 
Detroit Sulfur Dioxide Nonattainment Area, 87 FR 61514, Oct. 12, 
2022, at p. 61522; see also SO2 Guideline Document, U.S. 
Environmental Protection Agency, Office of Air Quality Planning and 
Standards, Research Triangle Park, NC 27711, EPA-452/R-94-008, 
February 1994 (1994 SO2 Guideline); Guidance for 1-Hour 
SO2 Nonattainment Area SIP Submissions, Office of Air 
Quality Planning and Standards, Stephen D. Page, April 23, 2014.
    \267\ Id.
    \268\ Guidance for 1-Hour SO2 Nonattainment Area SIP 
Submissions, Office of Air Quality Planning and Standards, Stephen 
D. Page, April 23, 2014, at p. 69.
    \269\ 87 FR 61514, Oct. 12, 2022, at p. 61522.
    \270\ Id.
---------------------------------------------------------------------------

    By contrast, PM2.5 NAAQS nonattainment areas typically 
include hundreds or thousands of individual sources (including multiple 
categories of major stationary, area, and mobile sources) of emissions 
of direct PM2.5 and multiple PM2.5 precursors. 
Thus, it is not appropriate for a state or the EPA to presume that a 
failure to meet RFP or to attain is presumptively the result of a 
single easily identified source to have violated the emissions 
limitations in an attainment plan for the PM2.5 NAAQS.
    Accordingly, the EPA has assessed whether the situation in the 
Fairbanks PM2.5 Nonattainment Area is sufficiently analogous 
to an SO2 nonattainment area to warrant extending the EPA's 
approach to SO2 contingency measures to Alaska's enforceable 
commitments. The EPA acknowledges that the emissions inventories and 
RFP provisions of the Fairbanks Revised 189(d) Plan make clear that the 
dominant contributor to elevated PM2.5 concentrations in the 
nonattainment area is the solid fuel-burning device source category, 
i.e., wood stoves. The EPA has approved Alaska's control strategy as 
meeting BACM for this source category and is proposing to determine 
that the Fairbanks Revised 189(d) Plan meets the CAA section 189(d) 
requirements. Thus, a failure to achieve RFP or QM requirements, or to 
achieve attainment could be attributable to widespread noncompliance 
with preexisting measures limiting emissions from the solid fuel-
burning device source category. Although comprised of numerous 
relatively small sources, widespread noncompliance could cumulatively 
be comparable to that by a single major stationary source.
    Therefore, if the State were to fail to meet an RFP or QM 
requirement or fail to attain the NAAQS by the applicable attainment 
date, then improving compliance with the Solid Fuel-Burning Appliance 
Curtailment Program and date certain removal requirement could be 
critical to ensuring the area achieves progress towards attainment. As 
previously discussed, the EPA is proposing to approve the State's 
determination that there are no other feasible measures that would meet 
contingency measures requirements. The EPA also acknowledges that 
Alaska's methods of assessing current and predicting future compliance 
rates with its control strategy have improved over time. This is 
evident by the results of Alaska's Fairbanks Winter Home Heating Energy 
Model and Multiple Residential Heating Surveys.\271\ In these ways, the 
situation in Fairbanks shares similarities to SO2 
nonattainment areas.
---------------------------------------------------------------------------

    \271\ State Air Quality Control Plan, Vol. II, section 
III.D.7.6.9.3.
---------------------------------------------------------------------------

    However, critical distinctions remain that suggest the Fairbanks 
PM2.5 Nonattainment Area should not be treated the same as 
an SO2 nonattainment area for the purposes of contingency 
measures requirements. In particular, the major contributors to ambient 
PM2.5 levels in Fairbanks are wood stoves, which emit direct 
PM2.5, and oil furnaces, which emit SO2, a 
PM2.5 precursor for area source purposes. There are tens of 
thousands of these area sources throughout the nonattainment area.\272\ 
They vary in make, model, age, and emissions potential.\273\ 
Importantly, actual emissions are highly dependent on operator 
behavior--particularly for wood stoves. This is different from the 
single or handful of major stationary sources that a state typically 
regulates in SO2 NAAQS nonattainment areas.
---------------------------------------------------------------------------

    \272\ Id.
    \273\ Id.
---------------------------------------------------------------------------

    By extension, measuring and predicting compliance with controls on 
wood stoves and oil furnaces is less precise than SO2 
emissions controls on major stationary sources. In addition, assuring 
compliance by thousands of individual wood stove operators is 
significantly more resource intensive than enforcement against an 
SO2 source--particularly in detecting violations. Thus, 
while a comprehensive enforcement program to assure compliance by major 
stationary sources in SO2 nonattainment areas satisfies the

[[Page 1631]]

CAA requirement that contingency measures be comprised of ``specific 
measures'' that would ``take effect with minimal further action by the 
state or EPA'' following a triggering event, this is not the case for 
PM2.5 nonattainment areas.\274\
---------------------------------------------------------------------------

    \274\ The EPA solicits comments on this assessment and 
conclusion. Given that Alaska's enforceable commitments meet all 
other requirements in 40 CFR 51.1014, the EPA may approve these 
commitments as contingency measures if commenters provide a 
compelling basis to show that the EPA should treat the Fairbanks 
PM2.5 Nonattainment Area as analogous to an 
SO2 nonattainment area for the purposes of contingency 
measures.
---------------------------------------------------------------------------

    Thus, the EPA proposes to approve the enforceable commitments in 
State Air Quality Control Plan, Vol. II, section III.D.7.2.1 as SIP-
strengthening that will enhance the State's overall approach to 
attaining and maintaining the NAAQS in the Fairbanks PM2.5 
Nonattainment Area.
d. Sufficiency of Emissions Reductions From Alaska's Contingency 
Measures
    Alaska's contingency measure, reducing the solid fuel-burning 
device curtailment thresholds, would achieve approximately 0.086 tons 
per day PM2.5 emissions reductions with an increase of 0.047 
tons per day SO2 emissions.\275\ This falls short of the one 
year's worth of progress metric for both pollutants, 0.102 tons per 
episode day of direct PM2.5 emissions and 0.115 tons per day 
of SO2 emissions. The estimates of emissions reductions from 
the other two contingency measures related to enhanced enforcement are 
not included in this calculation because the EPA is proposing to 
approve them as SIP-strengthening measures. However, as discussed in 
section II.G.3 of this preamble, the EPA proposes to determine that 
Alaska has provided a reasoned justification for why the state cannot 
adopt additional contingency measures to make up the shortfall.
---------------------------------------------------------------------------

    \275\ Applying Alaska's interpollutant trading mechanism, the 
combined emissions reductions for PM2.5 and 
SO2 are estimated to be 0.077 tons per day, representing 
62 percent of the one year's of interpollutant emissions reductions 
for PM2.5 and SO2. See State Air Quality 
Control Plan, Vol. II, section III.D.7.11.5.2; see also State Air 
Quality Control Plan, Vol. II, section III.D.7.11, Table 7.11-6.
---------------------------------------------------------------------------

    Based on the reasons in the preceding paragraphs, the EPA is 
proposing to approve the Fairbanks Revised 189(d) Plan as meeting the 
contingency measures requirements in CAA section 172(c)(9) and 40 CFR 
51.1014.

H. Motor Vehicle Emission Budgets for Transportation Conformity

1. Statutory and Regulatory Requirements Regarding the Motor Vehicle 
Emission Budgets
    CAA section 176(c) requires Federal activities in nonattainment and 
maintenance areas to conform to the SIP's purpose of eliminating or 
reducing the severity and number of violations of the NAAQS and 
achieving expeditious attainment of the standards. Conformity to the 
SIP means that such activities will not: (1) cause or contribute to any 
new violation of a NAAQS; (2) increase the frequency or the severity of 
an existing violation; or (3) delay timely attainment of any NAAQS or 
interim milestones.
    Transportation plans, transportation improvement programs (TIPs), 
and transportation projects involving Federal Highway Administration 
(FHWA) or Federal Transit Administration (FTA) funding or approval are 
subject to the transportation conformity rule (40 CFR 51.390 and part 
93, subpart A). Under this rule, metropolitan planning organizations 
(MPOs) in nonattainment and maintenance areas coordinate with state air 
quality and transportation agencies, the EPA, FHWA and FTA to 
demonstrate that an area's transportation plan and TIP conform to the 
applicable SIP. This demonstration typically includes a regional 
emissions analysis that shows that estimated emissions from existing 
and planned highway and transit systems are less than or equal to the 
SIP's motor vehicle emissions budgets (``budgets'') that the EPA has 
found adequate or approved. An attainment plan for the PM2.5 
NAAQS should include budgets for the attainment year and each required 
RFP year, as appropriate. Budgets are generally established for 
specific years and specific pollutants or precursors and reflect all of 
the motor vehicle control measures contained in the attainment and RFP 
demonstrations (40 CFR 93.118(e)(4)(v)).
    Attainment plans for PM2.5 NAAQS would identify motor 
vehicle emission budgets for the attainment year and each RFP year for 
direct PM2.5 and typically for NOX (unless 
certain criteria are met in the transportation conformity rule, see 40 
CFR 93.102(b)(2)(iv)), and for VOCs, SO2, and NH3 
if certain criteria in the transportation conformity rule are met (see 
40 CFR 93.102(b)(2)(v)). Direct PM2.5 emission budgets would 
include direct PM2.5 motor vehicle emissions from tailpipe, 
brake wear, and tire wear. A state should also consider whether re-
entrained paved and unpaved road dust are significant contributors and 
should be included in the direct PM2.5 budget. See 40 CFR 
93.102(b) and 93.122(f) and the conformity rule preamble at 69 FR 
40004, July 1, 2004, at pp. 40031-40036.\276\
---------------------------------------------------------------------------

    \276\ For further information on transportation conformity 
rulemakings, policy guidance and outreach materials, see the EPA's 
website at https://www.epa.gov/state-and-local-transportation.
---------------------------------------------------------------------------

2. Summary of the EPA's Prior Action Regarding the Motor Vehicle 
Emission Budgets
    The EPA disapproved the budgets for the Fairbanks PM2.5 
Nonattainment Area in the December 5, 2023, final rule.\277\ The EPA 
evaluated the motor vehicle emissions budgets developed by Alaska 
against our adequacy criteria in 40 CFR 93.118(e)(4) as part of our 
review of the submitted SIP. The EPA found that the budgets were 
clearly identified and precisely quantified using MOVES2014b, with 
appropriate consultation among Federal, State, and local agencies. 
However, the EPA found that the budgets did not meet other adequacy 
criteria: the budgets, when considered together with all other 
emissions sources, must be consistent with applicable RFP or attainment 
requirements, and must be consistent with and clearly related to the 
emissions inventory and the control measures in the SIP, see 40 CFR 
93.118(e)(4)(iv) and (v). Because the control strategy in the Fairbanks 
Serious Plan and Fairbanks 189(d) Plan did not include all required 
control measures, the budgets did not reflect all the required control 
measures.
---------------------------------------------------------------------------

    \277\ 88 FR 84626, December 5, 2023, at p. 84676.
---------------------------------------------------------------------------

3. Summary of the State's Submission Regarding the Motor Vehicle 
Emission Budgets
    The Fairbanks Revised 189(d) Plan includes budgets for direct 
PM2.5 for each of the upcoming RFP years (2023, 2026, and 
2029) and the 2027 attainment year identified by Alaska. Budgets for 
NOX were not included because Alaska demonstrated that 
NOX does not significantly contribute to PM2.5 
formation in the Fairbanks PM2.5 Nonattainment Area, and the 
EPA finalized approval of that precursor demonstration on December 5, 
2023.\278\ For VOC, SO2 and NH3, in accordance 
with 40 CFR 93.102(b)(2)(v), transportation-related emissions of these

[[Page 1632]]

precursors have not been found to be significant.\279\
---------------------------------------------------------------------------

    \278\ See section II.B.2. Note that 40 CFR 93.102(b)(2)(iv) 
indicates that NOX would apply in transportation 
conformity unless the appropriate finding has been made or if the 
SIP does not establish a budget for NOX.
    \279\ Under 40 CFR 93.102(b)(2)(v), the requirements of the 
transportation conformity rule apply for VOC, SO2, and/or 
NH3 in a PM2.5 area if either (1) the EPA 
Regional Administrator or the director of the state air agency makes 
a finding that transportation-related emissions of any of these 
precursors within the nonattainment area are a significant 
contributor to the PM2.5 nonattainment problem and has so 
notified the MPO and DOT, or (2) if the applicable implementation 
plan or submission establishes an approved or adequate budget for 
such emissions as part of the reasonable further progress, 
attainment or maintenance strategy. Because neither criterion is met 
for the Fairbanks area, budgets were not included for VOC, 
SO2, and NH3.
---------------------------------------------------------------------------

    The direct PM2.5 budgets were calculated using the 
MOVES3 vehicle emissions model, which was the latest on-road mobile 
sources emissions model available at the time Alaska started developing 
the attainment plan inventory. Although a major model update was 
released in September 2023, MOVES4, the motor vehicle emission budgets 
were developed using MOVES3.0.3 (released January 2022) as significant 
work had already been completed on the SIP amendment prior to the 
release of MOVES4. The use of MOVES3 was agreed upon following 
consultation with applicable Federal, state, and local agencies.
    Alaska used local fleet and fuel inputs and the Fairbanks Area 
Surface Transportation Planning (FAST Planning) travel demand model to 
generate local vehicle travel activity estimates over the six-month 
nonattainment season (October through March). The average winter day 
emissions were used by Alaska to set the motor vehicle emissions 
budgets. Exceedances of the 2006 24-hour PM2.5 NAAQS in the 
Fairbanks PM2.5 Nonattainment Area occur almost exclusively 
during the winter months. Alaska executed MOVES3 with locally developed 
inputs representative of wintertime 2019-2020 conditions. Table 6 of 
this preamble summarizes the regional average winter day on-road 
vehicle PM2.5 emission budgets and the related CAA milestone 
for the nonattainment area.

     Table 6--PM2.5 Motor Vehicle Emission Budgets by Milestone Year
------------------------------------------------------------------------
                             PM2.5 on-road
       Calendar year         budgets (tons      CAA-related milestone
                               per day)
------------------------------------------------------------------------
2020......................           0.074  Base year.
2023......................           0.062  RFP.
2026......................           0.054  RFP.
2027......................           0.052  Attainment.
2029......................           0.049  RFP.
------------------------------------------------------------------------
Source: State Air Quality Control Plan, Vol II, section III.D.7.14,
  Table 7.14-2.

4. The EPA's Evaluation and Proposed Action Regarding the Motor Vehicle 
Emission Budgets
    We have evaluated the motor vehicle emissions budgets developed by 
Alaska against our adequacy criteria in 40 CFR 93.118(e)(4) as part of 
our review. Because the EPA believes the budgets meet the criteria in 
the transportation conformity regulation at 40 CFR 93.118(e)(4), the 
EPA proposes to approve them as part of this SIP submission that 
addresses attainment and RFP.
    The Fairbanks Revised 189(d) Plan was submitted by the Alaska 
Governor's designee--the Commissioner of Alaska Department of 
Environmental Conservations.\280\ Consultation among Federal, State, 
and local agencies occurred prior to Alaska's submission of the 
Fairbanks Revised 189(d) Plan.\281\ This consultation is documented in 
the State Air Quality Control Plan, Vol. II, section III.D.7.14. The 
budgets are clearly identified and precisely quantified (40 CFR 
93.118(e)(4)(iii)).\282\ The EPA proposes to find that the budgets are 
consistent with applicable RFP and attainment requirements (40 CFR 
93.118(e)(4)(iv)), as well as the emissions inventory and control 
measures in the Fairbanks Revised 189(d) Plan (40 CFR 93.118(e)(4)(v)). 
The Fairbanks Revised 189(d) Plan also includes Alaska's explanations 
and documentation for any revisions to the Fairbanks Serious Plan and 
initial Fairbanks 189(d) Plan, including revisions to control measures, 
previously submitted budgets, and prior attainment projections.\283\
---------------------------------------------------------------------------

    \280\ 40 CFR 93.118(e)(4)(i).
    \281\ 40 CFR 93.118(e)(4)(ii).
    \282\ 40 CFR 93.118(e)(4)(vi).
    \283\ 40 CFR 93.118(e)(4)(vi).
---------------------------------------------------------------------------

    In addition to proposing approval of the budgets, the EPA is also 
initiating the adequacy review process for the budgets in this proposed 
rulemaking. When reviewing submitted SIPs containing budgets, the EPA 
reviews budgets for adequacy. Once the EPA affirmatively finds the 
submitted budget is adequate for transportation conformity purposes, 
that budget must be used by state and Federal agencies in determining 
whether proposed transportation activities conform to the SIP as 
required by section 176(c) of the CAA. See 40 CFR 93.118(e)(4)(1).\284\ 
The EPA may find budgets adequate before the SIP is approved in a final 
rule.
---------------------------------------------------------------------------

    \284\ However, the budgets in submitted implementation plans do 
not supersede the budgets in an approved SIP submission for the same 
CAA requirement and the period of years addressed by the previously 
approved SIP submission, unless the EPA specifies otherwise in its 
approval of a SIP submission. 40 CFR 93.118(e)(4)(1).
---------------------------------------------------------------------------

    The substantive criteria the EPA uses for determining adequacy of a 
budget are set out in 40 CFR 93.118(e)(4); these criteria were 
discussed above as the basis for the EPA's proposed approval. The 
process for determining adequacy is found in 40 CFR 93.118(f) and 
consists of three basic steps: (1) public notification of a SIP 
submission; (2) a public comment period; and (3) the EPA's adequacy 
determination. The EPA can begin an adequacy review through a proposed 
rulemaking in the Federal Register based on the transportation 
conformity regulation at 40 CFR 93.118(f)(2). This proposed rulemaking 
notifies the public that the EPA has received a SIP submission with 
budgets that the EPA will review for adequacy and begins the public 
comment period. The EPA invites the public to comment on the adequacy 
of budgets as well as other actions the EPA is proposing in this 
proposed rulemaking. Comments must be submitted by the close of the 
comment period. See the DATES section of this document for details.
    Interested members of the public can access the Fairbanks Revised 
189(d) Plan and other relevant information at https://www.regulations.gov, under Docket ID No. EPA-R10-OAR-0595. Following 
the EPA's public comment period, the EPA will consider any comments 
received.

III. Summary of Proposed Action

A. Proposed Approval

    In this action, the EPA is proposing to approve the submitted 
revisions to the Alaska SIP as meeting the following Serious Plan and 
CAA section 189(d) \285\ required elements for the 2006 24-hour 
PM2.5 NAAQS Fairbanks Nonattainment Area:
---------------------------------------------------------------------------

    \285\ 42 U.S.C. 7513a(d).
---------------------------------------------------------------------------

    1. The 2020 base year emissions inventory (CAA section 172(c)(3); 
\286\ 40 CFR 51.1008(c)(1)) for areas subject to CAA section 189(d));
---------------------------------------------------------------------------

    \286\ 42 U.S.C. 7502(c)(3).

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[[Page 1633]]

    2. The 2027 attainment projected emissions inventory (CAA section 
172(c)(1); \287\ 40 CFR 51.1008(c)(2));
---------------------------------------------------------------------------

    \287\ 42 U.S.C. 7502(c)(1).
---------------------------------------------------------------------------

    3. The State's PM2.5 major stationary source precursor 
demonstration for SO2 emissions (CAA section 189(e); \288\ 
40 CFR 51.1006(a));
---------------------------------------------------------------------------

    \288\ 42 U.S.C. 7513a(e).
---------------------------------------------------------------------------

    4. The control strategy as meeting the BACM requirements under CAA 
section 189(b)(1)(B) \289\ and 40 CFR 51.1010(a) for the following 
emission source categories:
---------------------------------------------------------------------------

    \289\ 42 U.S.C. 7513a(b)(1)(B).
---------------------------------------------------------------------------

    a. Requirements for wood sellers;
    b. Coal-fired heating devices;
    c. Coffee roasters;
    d. Weatherization and energy efficiency measures; and
    e. Mobile source emissions;
    5. Control strategy BACT requirements for direct PM2.5 
emissions (CAA section 189(b)(1)(B) \290\ and 40 CFR 51.1010(a)) for 
the following emission sources:
---------------------------------------------------------------------------

    \290\ Id.
---------------------------------------------------------------------------

    a. Chena Power Plant;
    b. Doyon-Fort Wainwright Central Heating and Power Plant;
    c. University of Alaska Fairbanks Power Plant;
    d. Zehnder Facility;
    e. North Pole Power Plant;
    6. Additional measures (beyond those already adopted in previous 
nonattainment plan SIP submissions for the area as RACM/RACT, BACM/
BACT, and Most Stringent Measures (MSM) (if applicable) under CAA 
section 189(d) \291\ and 40 CFR 51.1010(c);
---------------------------------------------------------------------------

    \291\ 42 U.S.C. 7513a(d).
---------------------------------------------------------------------------

    7. Attainment demonstration and modeling meeting the requirements 
of CAA sections 188(c)(2) and 189(b)(1)(A) \292\ and 40 CFR 51.1003(c) 
and 51.1011;
---------------------------------------------------------------------------

    \292\ 42 U.S.C. 7513(c)(2); 7513a(b)(1)(A).
---------------------------------------------------------------------------

    8. Reasonable further progress provisions meeting the requirements 
of CAA section 172(c)(2) \293\ and 40 CFR 51.1012;
---------------------------------------------------------------------------

    \293\ 42 U.S.C. 7502(c)(2).
---------------------------------------------------------------------------

    9. Motor vehicle emission budgets meeting the requirements under 40 
CFR 93.118;
    10. Quantitative milestones meeting the requirements of CAA section 
189(c) \294\ and 40 CFR 51.1013;
---------------------------------------------------------------------------

    \294\ 42 U.S.C. 7513a(c).
---------------------------------------------------------------------------

    11. Contingency measures meeting the requirements of CAA section 
172(c)(9) \295\ and 40 CFR 51.1014 applicable to Serious areas subject 
to CAA section 189(b) and 189(d).
---------------------------------------------------------------------------

    \295\ 42 U.S.C. 7502(c)(9).
---------------------------------------------------------------------------

    The EPA is proposing to approve the following submitted sections of 
the State Air Quality Control Plan for the Fairbanks PM2.5 
Nonattainment Area, State effective December 14, 2024:
    1. Volume II, section III.D.7.06 Emissions Inventory;
    2. Volume II, section III.D.7.07 Control Strategy;
    3. Volume II, section III.D.7.08 Modeling;
    4. Volume II, section III.D.7.09 Attainment Demonstration;
    5. Volume II, section III.D.7.10 Reasonable Further Progress and 
Quantitative Milestones;
    6. Volume II, section III.D.7.11 Contingency Measures;
    7. Volume II, section III.D.7.12 Emergency Episode Plan;
    8. Volume II, section III.D.7.14 Conformity and Motor Vehicle 
Emission Budgets;
    9. Volume III, Appendix III.D.7.06 Emissions Inventory;
    10. Volume III, Appendix III.D.7.07 Control Strategy; \296\
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    \296\ The EPA is not proposing to take action on Alaska's 
SO2 BACT determinations in State Air Quality Control 
Plan, Vol. III, Appendix III.D.7.7 at this time. If the EPA does not 
finalize approval of the SO2 precursor demonstration, 
then the EPA will propose action on Alaska's SO2 BACT 
determinations separately.
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    11. Volume III, Appendix III.D.7.08 Modeling;
    12. Volume III, Appendix III.D.7.09 Attainment Demonstration;
    13. Volume III, Appendix III.D.7.10 Reasonable Further Progress and 
Quantitative Milestones;
    14. Volume III, Appendix III.D.7.14 Conformity and Motor Vehicle 
Emission Budgets.
    The EPA is also proposing to approve and incorporate by reference 
submitted regulatory changes into the Alaska SIP. Upon final approval, 
the Alaska SIP will include the following regulations, State effective 
December 8, 2024:
    1. 18 AAC 50.055 (industrial processes and fuel-burning equipment 
requirements), except (d)(2)(B);
    2. 18 AAC 50.076 (solid fuel-fired heating device fuel 
requirements; registration of commercial wood sellers), except (g)(11);
    3. 18 AAC 50.077 (standards for wood fired heating devices), except 
(g);
    4. 18 AAC 50.078 (additional control measures for a serious 
PM2.5 nonattainment area), except (c);
    5. 18 AAC 50.079 (provisions for coal-fired heating devices); and
    6. 18 AAC 50.081 (Real estate transaction requirements; 
weatherization and energy efficiency).
    The EPA is also proposing to approve and incorporate by reference 
submitted permits into the Alaska SIP. Upon final approval, the Alaska 
SIP will include:
    1. Minor Permit AQ1121MSS04 Rev. 1, Title Page, Table of Contents, 
List of Abbreviations and Acronyms, Section 1, Section 3, Section 4, 
and Section 6, only, State effective December 14, 2024 (Doyon 
Utilities, LLC--Fort Wainwright (Privatized Emission Units);
    2. Minor Permit AQ0236MSS03 Rev. 2, Title Page, Table of Contents, 
List of Abbreviations and Acronyms, Section 1, Section 3, Section 4, 
and Section 6, only State effective December 14, 2024 (U.S. Army 
Garrison Fort Wainwright);
    3. Minor Permit AQ0110MSS01 Rev. 1, Title Page, Table of Contents, 
List of Abbreviations and Acronyms, Section 1, Section 3, Section 4, 
and Section 6, only, State effective December 14, 2024 (Golden Valley 
Electric Association, North Pole Power Plant);
    4. Minor Permit AQ0109MSS01 Rev. 2, Title Page, Table of Contents, 
List of Abbreviations and Acronyms, Section 1, Section 3, Section 4, 
and Section 6, only, State effective December 14, 2024 (Golden Valley 
Electric Association, Zehnder Facility);
    5. Minor Permit AQ0315MSS02 Revision 1, Title Page, Table of 
Contents, List of Abbreviations and Acronyms, Section 1, Section 3, 
Section 4, and Section 6, only, State effective December 14, 2024 
(Aurora Energy LLC, Chena Power Plant);
    6. Minor Permit AQ0316MSS08 Revision 1, Title Page, Table of 
Contents, List of Abbreviations and Acronyms, Section 1, Section 3, 
Section 4, and Section 6, only, State effective December 14, 2024 
(University of Alaska Fairbanks, University of Alaska Fairbanks 
Campus).

B. Adequacy Process

    In this action, the EPA is also initiating the adequacy process for 
the PM2.5 budgets included in this SIP submission. For 
further details, see section II.H.4.

IV. Interim Final Determination and Deferral of Sanctions

    Please see the EPA's Interim Final Determination published in the 
``Rules'' section of this Federal Register.

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 the regulations described in section III. of 
this document. The EPA has made, and will continue to make, these 
materials generally available through https://www.regulations.gov and 
at the EPA Region 10 Office (please contact the person identified in 
the FOR FURTHER

[[Page 1634]]

INFORMATION CONTACT section of this document for more information).

VI. Statutory and Executive Order Reviews

    Additional information about these statutes and Executive Orders 
can be found at https://www.epa.gov/laws-regulations/laws-and-executive-orders.

A. Executive Order 12866: Regulatory Planning and Review as Amended by 
Executive Order 14094: Modernizing Regulatory Review

    This action is not a significant regulatory action and was 
therefore not submitted to the Office of Management and Budget (OMB) 
for review.

B. Paperwork Reduction Act (PRA) (44 U.S.C. 3401 et. seq.)

    This action does not impose an information collection burden under 
the PRA, because this proposed SIP approval, if finalized, will not in-
and-of itself create any new information collection burdens, but will 
simply approve certain State requirements for inclusion in the SIP.

C. Regulatory Flexibility Act (RFA) (5 U.S.C. 601 et. seq.)

    I certify that this action will not have a significant economic 
impact on a substantial number of small entities under the RFA. This 
action will not impose any requirements on small entities. This 
proposed SIP approval, if finalized, will not in-and-of itself create 
any new requirements but will simply approve certain State requirements 
for inclusion in the SIP.

D. Unfunded Mandates Reform Act (UMRA) (Pub. L. 104-4)

    This action does not contain any unfunded mandate as described in 
UMRA, 2 U.S.C. 1531-1538, and does not significantly or uniquely affect 
small governments. This action proposes to approve certain pre-existing 
requirements under State or local law and imposes no new requirements. 
Accordingly, no additional costs to State, local, or Tribal 
governments, or to the private sector, result from this action.

E. Executive Order 13132: Federalism

    This action does not have federalism implications. It will not have 
substantial direct effects on the states, on the relationship between 
the national government and the states, or on the distribution of power 
and responsibilities among the various levels of government.

F. Executive Order 13175: Coordination With Indian Tribal Governments

    This action does not have Tribal implications, as specified in 
Executive Order 13175, because the SIP revision that EPA is proposing 
to approve would not 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, and will not impose substantial direct costs on 
Tribal governments or preempt Tribal law. Thus, Executive Order 13175 
does not apply to this action.

G. Executive Order 13045: Protection of Children From Environmental 
Health Risks and Safety Risks

    The EPA interprets Executive Order 13045 as applying only to those 
regulatory actions that concern environmental health or safety risks 
that the EPA has reason to believe may disproportionately affect 
children, per the definition of ``covered regulatory action'' in 
section 2-202 of the Executive Order. This action is not subject to 
Executive Order 13045 because this proposed SIP approval, if finalized, 
will not in-and-of itself create any new regulations, but will simply 
approve certain State requirements for inclusion in the SIP.

H. Executive Order 13211: Actions That Significantly Affect Energy 
Supply, Distribution, or Use

    This action is not subject to Executive Order 13211, because it is 
not a significant regulatory action under Executive Order 12866.

I. National Technology Transfer and Advancement Act (NTTAA)

    Section 12(d) of the NTTAA directs the EPA to use voluntary 
consensus standards in its regulatory activities unless to do so would 
be inconsistent with applicable law or otherwise impractical. The EPA 
believes that this action is not subject to the requirements of section 
12(d) of the NTTAA because application of those requirements would be 
inconsistent with the CAA.

J. Executive Order 12898: Federal Actions To Address Environmental 
Justice in Minority Populations and Low-Income Population

    Executive Order 12898 (Federal Actions To Address Environmental 
Justice in Minority Populations and Low-Income Populations, 59 FR 7629, 
February 16, 1994) directs Federal agencies to identify and address 
``disproportionately high and adverse human health or environmental 
effects'' of their actions on communities with environmental justice 
(EJ) concerns to the greatest extent practicable and permitted by law. 
Executive Order 14096 (Revitalizing Our Nation's Commitment to 
Environmental Justice for All, 88 FR 25251, April 26, 2023) builds on 
and supplements Executive Order 12898 and defines EJ as, among other 
things, the just treatment and meaningful involvement of all people, 
regardless of income, race, color, national origin, or Tribal 
affiliation, or disability in agency decision-making and other Federal 
activities that affect human health and the environment.''
    The air agency did not evaluate EJ considerations as part of its 
SIP submission; the CAA and applicable implementing regulations neither 
prohibit nor require such an evaluation. The EPA did not perform an EJ 
analysis and did not consider EJ in this action. Consideration of EJ is 
not required as part of this action, and there is no information in the 
record inconsistent with the stated goal of Executive Order 12898/14096 
of achieving EJ for communities with EJ concerns.

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: December 17, 2024.
Casey Sixkiller,
Regional Administrator, Region 10.
[FR Doc. 2024-30648 Filed 1-7-25; 8:45 am]
BILLING CODE 6560-50-P`