[Federal Register Volume 86, Number 114 (Wednesday, June 16, 2021)]
[Rules and Regulations]
[Pages 31927-31939]
[FR Doc No: 2021-12431]

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

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R09-OAR-2020-0589; FRL-10024-21-Region 9]

Air Plan Approval; Arizona; Stationary Sources; New Source Review
Updates

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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

SUMMARY: The Environmental Protection Agency (EPA) is taking final
action to approve revisions to the Arizona Department of Environmental
Quality's (ADEQ) portion of the Arizona State Implementation Plan (SIP)
that were submitted to the EPA by the ADEQ. These revisions concern the
ADEQ's SIP-approved rules for the issuance of New Source Review (NSR)
permits for stationary sources under the Clean Air Act (CAA or Act).
This action updates the ADEQ's NSR rules in the Arizona SIP and
corrects the remaining deficiencies in the ADEQ's NSR program that we
identified as the basis for our limited disapprovals in final
rulemaking actions in 2015 and 2016. Additionally, we are finding that
the ADEQ's SIP-approved NSR permitting program meets requirements for
visibility protection for major stationary sources under the Act and
are removing the Federal Implementation Plans (FIPs) for the ADEQ
related to these visibility protection requirements.

DATES: This rule is effective on July 16, 2021.

ADDRESSES: The EPA has established a docket for this action under
Docket ID No. EPA-R09-OAR-2020-0589. All documents in the docket are
listed on the https://www.regulations.gov website. Although listed in
the index, some information is not publicly available, e.g.,
Confidential Business Information (CBI) or other information the
disclosure of which is restricted by statute. Certain other material,
such as copyrighted material, is not placed on the internet and will be
publicly available only in hard copy form. Publicly available docket
materials are available through https://www.regulations.gov, or please
contact the person identified in the FOR FURTHER INFORMATION CONTACT
section for additional availability information. If you need assistance
in a language other

than English or if you are a person with disabilities who needs a
reasonable accommodation at no cost to you, please contact the person
identified in the FOR FURTHER INFORMATION CONTACT section.

FOR FURTHER INFORMATION CONTACT: Lisa Beckham, EPA Region IX, 75
Hawthorne St., San Francisco, CA 94105. By phone:<PHONE_NUMBER> or by
email at<EMAIL_ADDRESS>
SUPPLEMENTARY INFORMATION: Throughout this document, ``we,'' ``us,''
and ``our'' refer to the EPA.

Table of Contents

I. Proposed Action
II. Public Comments and EPA Responses
III. EPA Action
IV. Incorporation by Reference
V. Statutory and Executive Order Reviews

Definitions

    For this document, we are giving meaning to certain words or
initials as follows:
    (i) The words or initials Act or CAA mean or refer to the Clean Air
Act, unless the context indicates otherwise.
    (ii) The initials ADEQ mean or refer to the Arizona Department of
Environmental Quality.
    (iii) The initials Ag BMP mean or refer to the State of Arizona's
Agricultural Best Management Practices program.
    (iv) The initials ARS mean or refer to the Arizona Revised
Statutes.
    (v) The initials CBI mean or refer to confidential business
information.
    (vi) The initials CFR mean or refer to the Code of Federal
Regulations.
    (vii) The initials CO mean or refer to carbon monoxide.
    (viii) The words EPA, we, us or our mean or refer to the United
States Environmental Protection Agency.
    (ix) The initials FIP mean or refer to Federal Implementation Plan.
    (x) The initials MMBtu/hr mean or refer to million British thermal
units per hour.
    (xi) The initials NAAQS mean or refer to the National Ambient Air
Quality Standards.
    (xii) The initials NESHAP mean or refer to the National Emission
Standards for Hazardous Air Pollutants.
    (xiii) The initials NNSR mean or refer to Nonattainment New Source
Review.
    (xiv) The initials NOX mean or refer to oxides of nitrogen.
    (xv) The initials NSPS mean or refer to New Source Performance
Standards.
    (xvi) The initials NSR mean or refer to New Source Review.
    (xvii) The initials PM2.5 mean or refer to particulate
matter with an aerodynamic diameter of less than or equal to 2.5
micrometers, or fine particulate matter.
    (xviii) The initials PM10 mean or refer to particulate
matter with an aerodynamic diameter of less than or equal to 10
micrometers.
    (xix) The initials PSD mean or refer to Prevention of Significant
Deterioration.
    (xx) The initials SER mean or refer to significant emission rate.
    (xxi) The initials SIP mean or refer to State Implementation Plan.
    (xxii) The initials SO2 mean or refer to sulfur dioxide.
    (xxiii) The words State or Arizona mean the State of Arizona,
unless the context indicates otherwise.
    (xxiv) The initials TSD mean or refer to the technical support
document for this action unless the context indicates otherwise.

I. Proposed Action

    On December 23, 2020 (85 FR 83868), the EPA proposed to approve
revisions to the ADEQ portion of the Arizona SIP consisting of several
rule revisions and demonstrations submitted by the ADEQ related to the
ADEQ's CAA NSR permitting program.
    First, we proposed to approve a July 22, 2020 SIP submittal from
the ADEQ that contains rule revisions and other demonstrations
primarily intended to correct deficiencies in the ADEQ's minor NSR
program (referred to hereinafter as the ``2020 Minor NSR submittal'').
The deficiencies being corrected by the 2020 Minor NSR submittal were
identified in a November 2, 2015 \1\ final limited approval and limited
disapproval action by the EPA (referred to hereinafter as the EPA's
``2015 NSR action'').\2\ Our 2015 NSR action was the result of an
extensive review of the ADEQ's NSR program, in response to a
comprehensive NSR program update submitted by the ADEQ to the EPA in a
2012 SIP revision (referred to hereinafter as the ``2012 NSR SIP
submittal''). The 2012 NSR SIP submittal represented the ADEQ's first
comprehensive update to its SIP-approved NSR program since the 1980s.
Our review of the 2012 NSR SIP submittal for compliance with CAA
requirements therefore included all aspects of the ADEQ's minor NSR,
Prevention of Significant Deterioration (PSD), and nonattainment NSR
(NNSR) permitting programs, including NSR-related visibility
requirements for major stationary sources. In a May 4, 2018 final
rule,\3\ we approved revisions to the ADEQ's NSR program, submitted to
the EPA in 2017, that corrected a large portion of the deficiencies
identified in our 2015 NSR action, primarily related to the PSD and
NNSR programs (referred to hereinafter as the ``2018 Major NSR
action''). Thus, the 2020 Minor NSR submittal that is the subject of
our present action addresses the remaining deficiencies from our 2015
NSR action.
---------------------------------------------------------------------------

    \1\ 80 FR 67319 (Nov. 2, 2015).
    \2\ In the 2015 NSR action, we also finalized other actions,
including a partial disapproval related to the fine particulate
matter (PM2.5) significant monitoring concentration, and
limited approvals, without corresponding limited disapprovals,
related to section 189(e) of the Act.
    \3\ 83 FR 19631 (May 4, 2018).
---------------------------------------------------------------------------

    Second, our December 23, 2020 proposed action also included our
proposed approval of a March 29, 2019 SIP submittal, and a January 14,
2020 supplemental submittal, from the ADEQ. These two submittals are
intended to resolve an ADEQ NNSR program deficiency related to the
permitting of ammonia as a precursor to PM2.5 in the West
Central Pinal and Nogales PM2.5 nonattainment areas (the
March 29, 2019 submittal and January 14, 2020 supplement are
collectively referred to hereinafter as the ``Ammonia PM2.5
NSR submittal''). In a June 22, 2016 \4\ final limited disapproval rule
action, we had identified additional deficiencies in the ADEQ's NNSR
program related to PM2.5 precursors (referred to hereinafter
as the EPA's ``2016 PM2.5 precursor action''). In our 2018
Major NSR action, in addition to approving rule revisions to the ADEQ's
NSR program, the EPA conditionally approved \5\ the ADEQ's NNSR program
pursuant to CAA section 110(k)(4) solely with respect to ammonia as a
precursor to PM2.5 under section 189(e) of the Act.\6\ We
found in our 2018 Major NSR action that the ADEQ's SIP revisions
otherwise resolved the deficiencies identified in our 2016
PM2.5 precursor action.\7\ In addition to resolving the
deficiency that was the basis for our conditional approval for ammonia
as a precursor to PM2.5 under CAA section 189(e), the
Ammonia PM2.5 NSR submittal also includes other

minor and technical rule revisions to the ADEQ's NSR program that we
proposed to approve in our December 23, 2020 proposed action.\8\
---------------------------------------------------------------------------

    \4\ 81 FR 40525 (June 22, 2016).
    \5\ 83 FR 19631, 19634. The conditional approval was based upon
a December 6, 2017 letter from the State committing to submit a SIP
revision to the EPA consisting of rule revisions and/or
demonstrations that would correct the deficiencies related to
ammonia as a precursor to PM2.5 under the NNSR program
requirements in CAA section 189(e). See 83 FR 19631, 19633-19634.
    \6\ Concurrent with our proposed conditional approval action in
2018, we made an interim final determination that the State of
Arizona had satisfied the requirements of part D of the CAA
permitting program for areas under the jurisdiction of ADEQ with
respect to PM2.5 precursors under section 189(e). See 83
FR 1195 (January 10, 2018) and 83 FR 1212 (January 10, 2018). The
effect of our interim final determination was that the imposition of
sanctions that had been triggered were deferred.
    \7\ See 83 FR 19631, 19633-19634.
    \8\ The ADEQ's January 14, 2020 submittal requested that
specific paragraphs from certain revised rules be added to the
Arizona SIP. The 2020 Minor NSR submittal clarified that the ADEQ
requests that the entirety of each revised rule (with one exception)
be included in the SIP, rather than only the selected paragraphs
identified in the earlier submittal.
---------------------------------------------------------------------------

    Finally, our December 23, 2020 proposal also included our proposed
determination that the ADEQ's SIP-approved NSR program meets the
visibility requirements for major NSR programs in 40 CFR 51.307.
Accordingly, we proposed to update 40 CFR 52.145(b) to remove the
existing visibility FIPs \9\ for those stationary sources subject to
the ADEQ's permitting jurisdiction.
---------------------------------------------------------------------------

    \9\ The visibility FIPs are implemented at 40 CFR 52.27 for
attainment areas and 40 CFR 52.28 for nonattainment areas.
---------------------------------------------------------------------------

    The EPA's proposal and technical support document (TSD) for this
rulemaking action have more information about the content of the ADEQ's
SIP submittals (collectively referred to hereinafter as the ``2019-20
NSR submittals''), the deficiencies in the ADEQ's NSR program that are
being corrected, and our rationale for proposing approval.
    The rules that the EPA proposed to approve into the ADEQ's portion
of the Arizona SIP are listed in Table 1 of this notice, and the
existing SIP-approved rules that we proposed to remove or supersede
from the SIP are listed in Table 2 of this notice. The rules are from
the Arizona Administrative Code, Title 18--Environmental Quality,
Chapter 2--Department of Environmental Quality--Air Pollution Control,
Articles 1, 3, and 4.\10\ These rules apply to all areas and stationary
sources in Arizona for which the ADEQ has permitting jurisdiction. The
ADEQ has permitting jurisdiction for the following stationary source
categories in all areas of Arizona: Smelting of metal ores, coal-fired
electric generating stations, petroleum refineries, Portland cement
plants, and portable sources. The ADEQ also has permitting jurisdiction
for major and minor sources in the following counties: Apache, Cochise,
Coconino, Gila, Graham, Greenlee, La Paz, Mohave, Navajo, Santa Cruz,
Yavapai, and Yuma. Finally, the ADEQ has permitting jurisdiction over
major sources in Pinal County (currently delegated to Pinal County Air
Quality Control District) and any source in Maricopa, Pima, or Pinal
County for which the ADEQ asserts jurisdiction.
---------------------------------------------------------------------------

    \10\ One older rule provision that we are removing from the
Arizona SIP, listed in Table 2, was from the Arizona Administrative
Code, Title 9, Chapter 3, Article 2.
    \11\ This rule contains a new provision stating that a
particular revised subsection, R18-2-101(131)(f), will take effect
on the effective date of the EPA Administrator's action approving it
as part of the Arizona SIP. Therefore, the revised version of R18-2-
101(131)(f) would become effective on the effective date of our
approval of the current submittal of R18-2-101.

                                            Table 1--Submitted Rules
----------------------------------------------------------------------------------------------------------------
                                                                                State
                       Rule                                             Title                     effective date
----------------------------------------------------------------------------------------------------------------
R18-2-101, except (20)............................  Definitions.................................   \11\ 2/1/2020
R18-2-301.........................................  Definitions.................................        2/1/2020
R18-2-302.........................................  Applicability; Registration; Classes of            3/21/2017
                                                     Permits.
R18-2-302.01......................................  Source Registration Requirements............        2/1/2020
R18-2-304.........................................  Permit Application Processing Procedures....        2/1/2020
R18-2-306.........................................  Permit Contents.............................       3/21/2017
R18-2-306.01......................................  Permits Containing Voluntarily Accepted            3/21/2017
                                                     Emission Limitations and Standards.
R18-2-317.........................................  Facility Changes Allowed Without Permit             8/7/2012
                                                     Revisions--Class I.
R18-2-317.01......................................  Facility Changes that Require a Permit              8/7/2012
                                                     Revision--Class II.
R18-2-317.02......................................  Procedures for Certain Changes that Do Not          8/7/2012
                                                     Require a Permit Revision--Class II.
R18-2-319.........................................  Minor Permit Revisions......................       3/21/2017
R18-2-320.........................................  Significant Permit Revisions................       3/21/2017
R18-2-334.........................................  Minor New Source Review.....................        2/1/2020
R18-2-406.........................................  Permit Requirements for Sources Located in          2/1/2020
                                                     Attainment and Unclassifiable Areas.
----------------------------------------------------------------------------------------------------------------

                                   Table 2--Rules To Be Removed or Superseded
----------------------------------------------------------------------------------------------------------------
                                                                                Federal
                    Rule                                Title               EPA approval date        Register
                                                                                citation
----------------------------------------------------------------------------------------------------------------
R18-2-101..................................  Definitions................  May 4, 2018..........     83 FR 19631
R18-2-301..................................  Definitions................  November 2, 2015.....     80 FR 67319
R18-2-302..................................  Applicability;               November 2, 2015.....     80 FR 67319
                                              Registration; Classes of
                                              Permits.
R18-2-302.01...............................  Source Registration          November 2, 2015.....     80 FR 67319
                                              Requirements.
R18-2-304..................................  Permit Application           November 2, 2015.....     80 FR 67319
                                              Processing Procedures.
R18-2-306..................................  Permit Contents............  November 2, 2015.....     80 FR 67319
R18-2-306.01...............................  Permits Containing           November 2, 2015.....     80 FR 67319
                                              Voluntarily Accepted
                                              Emission Limitations and
                                              Standards.
R18-2-319..................................  Minor Permit Revisions.....  November 2, 2015.....     80 FR 67319
R18-2-320..................................  Significant Permit           November 2, 2015.....     80 FR 67319
                                              Revisions.
R18-2-334..................................  Minor New Source Review....  November 2, 2015.....     80 FR 67319
R18-2-406..................................  Permit Requirements for      May 4, 2018..........     83 FR 19631
                                              Sources Located in
                                              Attainment and
                                              Unclassifiable Areas.
R9-3-217, paragraph A......................  Attainment Areas;            April 23, 1982.......     47 FR 17483
                                              Classification and
                                              Standards.
----------------------------------------------------------------------------------------------------------------

II. Public Comments and EPA Responses

    The EPA's proposal provided for a 30-day public comment period. We
received one set of comments from Arizona Center for Law in the Public
Interest and the Center for Biological Diversity (``the commenters'').
Below, we summarize the comments received and provide our responses.
The full text of the comments is available in the docket for this
action.
    Comment: The commenters state that the ADEQ's minor NSR program is
inadequate because it does not regulate ammonia and volatile organic
compounds (VOCs) as PM2.5 precursors. The commenters argue
that the EPA's approval of the 2020 Minor NSR submittal will interfere
with attainment of the PM2.5 National Ambient Air Qualtiy
Standard (NAAQS) in areas under the ADEQ's jurisdiction that are
designated nonattainment for PM2.5. The commenters argue
that this also means that the submittal does not comply with CAA
section 110(l) and Appendix V to 40 CFR part 51. Further, the
commenters argue that the 2020 Minor NSR submittal is insufficient
because it does not include a modeling demonstration that the
regulation of VOCs or ammonia is unnecessary to ensure protection of
the PM2.5 NAAQS.
    Response: As an initial matter, we note that the commenters'
argument that the ADEQ's minor NSR program must regulate VOCs and
ammonia as precursors to PM2.5 in PM2.5
nonattainment areas where the ADEQ has jurisdiction does not address
the specific revisions to the ADEQ's minor NSR program that are the
focus of the EPA's current action. As explained in section I of this
SUPPLEMENTARY INFORMATION section, the EPA previously undertook an
extensive review of the ADEQ's NSR program (minor NSR, PSD, and NNSR)
in 2015 to ensure that the program met all Clean Air Act requirements.
In our 2015 NSR action, we found that the ADEQ's updated program
largely met Clean Air Act requirements, but we identified a number of
specific deficiencies in our final action that needed to be corrected
in order for ADEQ to gain full approval from the EPA. Most of the
identified deficiencies were corrected and submitted to the EPA for
approval in 2017 and were approved in our 2018 Major NSR action. We are
currently acting on the ADEQ's 2019-20 NSR submittals that correct the
remaining deficiencies that we identified as the bases for our final
limited disapproval in our 2015 NSR action and that formed the basis
for the conditional approval in our 2018 Major NSR action. The EPA
found in our 2015 NSR action that the ADEQ's minor NSR program met all
the requirements for a minor NSR program in CAA section 110(a)(2)(C)
and 40 CFR 51.160-51.164 with the exception of specific deficiencies
that the ADEQ is now addressing with the 2020 Minor NSR submittal. In
light of the recent and extensive review and approval by the EPA of the
ADEQ's NSR program, we find that the commenters' concerns regarding
PM2.5 precursors in the ADEQ's minor NSR program are not
germane to the deficiencies with the ADEQ's minor NSR program that we
identified previously and that we are addressing in this action.
Nevertheless, we will explain why we disagree with the commenters that
the ADEQ's minor NSR program must regulate VOCs and ammonia as
precursors to PM2.5 in the areas where the ADEQ has
permitting jurisdiction, and why we disagree that the EPA's approval of
these revisions to the ADEQ's SIP-approved minor NSR program is
inconsistent with CAA section 110(l) and Appendix V to 40 CFR part 51.
    The commenters are concerned that this action will interfere with
attainment of the PM2.5 NAAQS in designated PM2.5
nonattainment areas under the ADEQ's permitting jurisdiction because
the ADEQ's minor NSR program and the 2020 Minor NSR submittal do not
specifically regulate ammonia and VOC as precursors to PM2.5
in the ADEQ's minor NSR program.\12\ As a result, the commenters
conclude, the 2020 Minor NSR submittal does not meet CAA section 110(l)
and section 2.2(d) of Appendix V to 40 CFR part 51. To support their
concerns, the commenters point generally to examples of operations that
can emit ammonia and VOC, and imply that the method to demonstrate that
this action complies with CAA section 110(l) and section 2.2(d) of
Appendix V to 40 CFR part 51 is through a modeling demonstration that
they assert is required by section 2.2(e) of Appendix V to 40 CFR part
51.
---------------------------------------------------------------------------

    \12\ The ADEQ's SIP-approved minor NSR program expressly
regulates oxides of nitrogen (NOX) and sulfur dioxide
(SO2) as PM2.5 precursors at R18-2-101(123).
---------------------------------------------------------------------------

    To evaluate the commenters' concerns, it is important to understand
the requirements in the Act governing how permitting authorities must
address precursors in NSR programs for nonattainment areas. Part D of
title I of the Act contains specific requirements for the development
of an NNSR program for major sources (and major modifications) in
nonattainment areas. Among other requirements, in a PM2.5
nonattainment area, the NNSR program must apply to major sources of
direct PM2.5 emissions and to major sources of
PM2.5 precursors, unless the EPA determines that such
precursor sources do not contribute significantly to PM2.5
levels that exceed the standard in the nonattainment area. See CAA
section 189(e). For purposes of the NNSR program, the EPA has
identified NOX, SO2, VOCs, and ammonia as
precursors to PM2.5. See 40 CFR 51.165(a)(1)(xxxvii)(C)(2).
Our proposed action explained that we have determined that the ADEQ's
NNSR program for PM2.5 fully satisfies CAA section 189(e),
and the commenters do not dispute this. The requirements of CAA section
189(e) do not, however, apply to NSR permitting under the minor NSR
program.
    The Act's requirements for minor NSR programs are far less
prescriptive in general than those applicable for NSR programs
regulating proposed new major sources and major modifications. CAA
section 110(2)(a)(C), which governs minor NSR programs, requires the
``regulation of the modification and construction of any stationary
source within the areas covered by the plan as necessary to assure that
national ambient air quality standards are achieved.'' (emphasis added)
The EPA's implementing regulations for minor NSR programs require that
such programs include legally enforceable procedures that enable the
state to determine whether the construction or modification of sources
will result in a violation of applicable portions of the control
strategy or interference with attainment or maintenance of the NAAQS,
and, if so, to prevent such construction or modification. See 40 CFR
51.160(a)-(b). States are not required to regulate the construction of
all new or modified stationary sources under their minor NSR programs;
rather, the procedures must identify the types and sizes of sources
regulated under the state's minor NSR program, and the state's plan
must discuss the basis for determining which sources will be subject to
review. 40 CFR 51.160(e).\13\ Thus, the Act provides considerable
discretion for permitting authorities to develop minor NSR programs
determined ``necessary'' to assure the NAAQS are achieved in their
respective geographic areas. Consistent with CAA section 110(a)(2)(C)
and the implementing regulations governing minor NSR programs at 40 CFR
51.160-

51.164, the EPA has determined, as explained in our proposal, that the
ADEQ's program now meets the relevant requirements for a minor NSR
program.
---------------------------------------------------------------------------

    \13\ The EPA's implementing regulations also include other
largely procedural requirements for minor NSR programs at 40 CFR
51.160-51.164.
---------------------------------------------------------------------------

    In response to the commenter's specific concerns here, we consider
the two PM2.5 nonattainment areas in Arizona--Nogales and
West Central Pinal. Regarding the Nogales area, where the ADEQ has
minor NSR permitting jurisdiction, the ADEQ's 2020 Minor NSR submittal
explains that ``[t]he Nogales PM2.5 nonattainment area was
found to have attained the 2006 24-hour PM2.5 NAAQS in
2017.'' \14\ Further, while the ADEQ's minor NSR program does not
specifically regulate VOC as a PM2.5 precursor, minor
sources of VOC are, in fact, regulated by the ADEQ's minor NSR program
at a source-wide permitting threshold of 20 tons per year. The 2020
Minor NSR submittal contains an analysis showing that this permitting
threshold is expected to cover at least 86% of VOC emissions in areas
subject to ADEQ permitting jurisdiction.\15\ For the West Central Pinal
PM2.5 nonattainment area, the Pinal County Air Quality
Control District, not the ADEQ, has primary permitting jurisdiction for
minor sources. Accordingly, the ADEQ's minor NSR permitting program
generally does not apply in the West Central Pinal PM2.5
nonattainment area.\16\
---------------------------------------------------------------------------

    \14\ 2020 Minor NSR submittal at 19; section <IP_ADDRESS>. See also
82 FR 21711 (May 10, 2017) (EPA determination of attainment by the
attainment date).
    \15\ 2020 Minor NSR submittal at 16; Table 4-2.
    \16\ We also note that the ADEQ's March 29, 2019 SIP revision
related to ammonia as a PM2.5 precursor provides results
from a 2010 ADEQ study that determined the speciation of
PM2.5 emissions in the West Central Pinal nonattainment
area. The study showed that 90% of PM2.5 emissions in the
West Central Pinal nonattainment area originate from direct
PM2.5 sources, and less than 10% from PM2.5
precursors. March 29, 2019 SIP submittal at 11; Table 3-3.
---------------------------------------------------------------------------

    Although the commenters mention certain types of operations that
may emit ammonia and VOCs, the commenters do not provide information or
explanation that demonstrates that the ADEQ's regulating those
pollutants as precursors to PM2.5 in the PM2.5
nonattainment areas under the ADEQ's jurisdiction as part of the ADEQ's
minor NSR program is necessary to achieve the PM2.5 NAAQS in
any such areas. As explained above, the only PM2.5
nonattainment area where the ADEQ has primary jurisdiction for minor
sources, the Nogales area, is already attaining the PM2.5
NAAQS. Moreover, in addition to regulating direct PM2.5
emissions, the ADEQ's minor NSR program regulates emissions of
NOX and SO2 as PM2.5 precursors and
regulates VOC emissions in general. In light of the information
described above, we find that the ADEQ's determination to not regulate
sources of ammonia and VOCs as PM2.5 precursors in its minor
NSR program in the PM2.5 nonattainment areas under its
jurisdiction is reasonable and not necessary to ensure that the
PM2.5 NAAQS are achieved.
    The commenters also indicate that the EPA's approval of the 2020
Minor NSR submittal conflicts with the requirement in CAA section
110(l) that the EPA ``shall not approve a revision of a plan if the
revision would interfere with any applicable requirement concerning
attainment and reasonable further progress. . .or any other applicable
requirement of this chapter.'' Our December 23, 2020 proposed approval
contained our analysis that our action met these requirements of CAA
section 110(l): ``We have determined that our action on the 2019-20 NSR
submittals would, as described herein, strengthen the applicable SIP.
This action is primarily intended to correct numerous deficiencies in
the ADEQ's NSR program and provides other revisions to enhance and
update the program. Accordingly, this action will not interfere with
attainment and reasonable further progress, or any other applicable
requirement.'' \17\ The commenters did not address this analysis or
explain how this action to correct deficiencies in the ADEQ's minor NSR
program will interfere with any applicable requirement concerning
attainment and reasonable further progress or any other CAA requirement
in the PM2.5 nonattainment areas under the ADEQ's
jurisdiction that are of concern to the commenter. This action
strengthens the overall SIP and does not relax any SIP requirements
related to attaining the PM2.5 NAAQS in Arizona.
---------------------------------------------------------------------------

    \17\ 85 FR 83868, 83876 (Dec. 23, 2020).
---------------------------------------------------------------------------

    The commenters make the related argument that the ADEQ's SIP
revision does not satisfy section 2.2(d) of Appendix V to 40 CFR part
51 because it does not regulate VOCs and ammonia as precursors to
PM2.5 and therefore interferes with attainment of the
PM2.5 NAAQS in areas under ADEQ's jurisdiction that are
designated nonattainment for PM2.5.\18\ As described above,
the 2019-20 SIP submittals contain sufficient information to support
our conclusion that the ADEQ's decision not to specifically regulate
VOC and ammonia as PM2.5 precursors for its minor NSR
program is acceptable and will not interfere with attainment of the
PM2.5 NAAQS.
---------------------------------------------------------------------------

    \18\ The commenters reference the portion of section 2.2(d) that
requires SIP submittals to ``demonstrat[e] that the national ambient
air quality standards, prevention of significant deterioration
increments, reasonable further progress demonstration, and
visibility, as applicable, are protected if the plan is approved and
implemented.'' See 40 CFR part 51, Appendix V, section 2.2(d).
---------------------------------------------------------------------------

    Lastly, in response to the commenter's argument that the ADEQ
should have included a modeling demonstration relating to ammonia and
VOC as PM2.5 precursors to meet the requirements of section
2.2(e) of Appendix V to 40 CFR part 51, the commenters have not
accurately characterized these requirements.\19\ We do not interpret
section 2.2(e) of Appendix V to require that every SIP submittal
contain a modeling demonstration, as implied by the commenters.
Instead, when a modeling demonstration is necessary and is therefore
included in a submittal to support the SIP revision, then the submittal
must also contain the underlying modeling information outlined in
section 2.2(e). We find that section 2.2(e) of Appendix V is not
applicable to the 2020 Minor NSR submittal because modeling was not
used to support this SIP revision nor was a modeling demonstration
required in this instance.
---------------------------------------------------------------------------

    \19\ Section 2.2(e) of Appendix V requires that a SIP submittal
include the ``[m]odeling information required to support the
proposed revision, including input data, output data, models used,
justification of model selections, ambient monitoring data used,
meteorological data used, justification for use of offsite data
(where used), modes of models used, assumptions, and other
information relevant to the determination of adequacy of the
modeling analysis.''
---------------------------------------------------------------------------

    Comment: The commenters consider the ADEQ's minor NSR thresholds of
one-half the ``significant'' emission rates (SERs) in the PSD program
\20\ to be arbitrary and unsupported by modeling or other evidence
demonstrating protection of the NAAQS, in violation of CAA section
110(l) and sections 2.2(d) and (e) in Appendix V to 40 CFR part 51. The
commenters argue that merely comparing the percentage of emissions
regulated by the ADEQ's program to other programs does not address
whether thresholds are ``protective of the NAAQS''. The commenters
assert that the ADEQ misplaced focus on the contributions of current
sources in nonattainment areas under its jurisdiction and whether those
areas are now violating the NAAQS. Instead, the ADEQ should have
focused on ensuring that additional sources (or new modifications of
existing sources) do not jeopardize attainment or maintenance of the
NAAQS in the future.
---------------------------------------------------------------------------

    \20\ See 40 CFR 51.166(b)(23)(i).
---------------------------------------------------------------------------

    Response: We respectfully disagree with the commenters that the
ADEQ has not provided an adequate rationale for

its permitting exemption thresholds for minor sources in nonattainment
areas and minor sources of PM2.5 in attainment areas under
CAA section 110(l) and Appendix V to 40 CFR part 51.
    First, we note that with the exception of the thresholds for
PM2.5 sources, in our 2015 NSR action, the EPA previously
approved the ADEQ's permitting thresholds for minor NSR as they apply
in attainment areas, and, accordingly, those thresholds were not
changed as part of the 2020 Minor NSR submittal. The EPA's prior
approval was based on the ADEQ's demonstration that the emissions from
the sources and projects to be exempted from its minor NSR program
under these thresholds were inconsequential to attainment or
maintenance of the NAAQS.\21\ However, in our 2015 NSR action, we also
determined that the ADEQ had not provided a rationale for the
PM2.5 permitting exemption threshold, nor had it provided an
adequate rationale for why the permitting exemption thresholds were
appropriate for nonattainment areas. \22\ In this action, we are
considering only the 2020 Minor NSR submittal and the ADEQ's rationale
for its permitting exemption thresholds as they apply to minor sources
in nonattainment areas, and to minor sources of PM2.5 in
attainment areas.
---------------------------------------------------------------------------

    \21\ In reviewing the ADEQ's minor NSR program under 40 CFR
51.160(e), we considered it appropriate for the ADEQ to exclude
emissions from its NSR program if such emissions would be
``inconsequential to attainment or maintenance of the NAAQS.'' 80 FR
67319, 67325. This was the same standard that the EPA used in
developing the permitting thresholds for its minor NSR program for
Indian country. 76 FR 38748, 38758 (Jul. 1, 2011).
    \22\ Id.
---------------------------------------------------------------------------

    The commenters specifically take issue with the ADEQ's comparing
the percentage of emissions regulated by its NSR program to the
percentage of emissions regulated by other NSR programs, and assert
that the ADEQ's approach should focus more on future sources of
emissions and ensuring that such sources do not jeopardize the NAAQS.
As described below, the ADEQ's approach did not rest solely on
comparing its permitting thresholds to other programs, and we find that
the approach ensures that the ADEQ's minor NSR program reviews the
necessary sources to ensure attainment and maintenance of the NAAQS.
    Prior to 2012, the ADEQ's minor NSR program required permitting of
non-major sources with potential emissions of a criteria pollutant at
or above the SERs from the PSD program reflected in 40 CFR
51.166(b)(23)(i). To address concerns raised by the EPA regarding these
historic permitting thresholds, the ADEQ assessed other potential lower
permitting thresholds for its minor NSR program and ultimately selected
revised, lower thresholds. In 2012, the ADEQ chose to use a method
similar to the method that the EPA used to develop permitting
thresholds under its minor NSR program applicable in Indian country,
known as the ``Tribal Minor NSR rule.'' \23\ To inform its selection of
minor NSR permitting thresholds in developing the Tribal Minor NSR
rule, the EPA conducted a source distribution analysis using data from
the National Emissions Inventory. The EPA's analysis concluded that the
percentage of emissions that would be exempt from minor NSR under the
Tribal Minor NSR rule's thresholds would be small (less than 1.5% of
total emissions for each pollutant), while the program's permitting
thresholds would require only 14-58% of stationary sources (varying
based on the individual pollutant) to obtain permits or register under
the Tribal Minor NSR rule. The EPA's analysis determined that this
approach provided ``evidence that sources with emissions below the
proposed minor NSR thresholds will be inconsequential to attainment and
maintenance of the NAAQS.'' \24\ We stated that the permitting
thresholds for the minor NSR program applicable in Indian country are
``not intended to establish a new set of minimum criteria that a Tribe
or a state would need to follow in developing its own minor source
permitting program.'' \25\ Nevertheless, the approach taken by the EPA
in developing the thresholds in the Tribal Minor NSR rule represents
one approach that EPA has found to be appropriate in establishing such
thresholds.
---------------------------------------------------------------------------

    \23\ 76 FR 38748 (July 1, 2011).
    \24\ 71 FR 48695, 48701-48703 (Aug. 21, 2006).
    \25\ 76 FR 38748, 38754.
---------------------------------------------------------------------------

    To assess potential thresholds for its minor NSR program, the ADEQ
applied a similar approach to a local data set. During the stakeholder
process, the ADEQ proposed two alternative scenarios for its revised
minor NSR thresholds: One that generally used one half of the PSD SERs
(Scenario 1) and one that generally used one quarter of the PSD SERs
(Scenario 2). The ADEQ's analysis looked at the percentage of emissions
that would be regulated at the two thresholds and concluded that ``both
scenarios result in a relatively large percentage of emissions being
subject to regulation compared to the percentage of sources brought
into the program.'' The results of the analysis showed that using
Scenario 2 for the minor NSR emission thresholds rather than Scenario 1
would result in significantly more coverage of carbon monoxide (CO) and
SO2 emissions under the ADEQ's minor NSR program. However,
the ADEQ reasoned that stationary source emissions of CO are generally
dwarfed by mobile source emissions and do not contribute significantly
to nonattainment of the CO NAAQS. Also, the ADEQ reasoned that in the
areas within Arizona that are subject to its minor NSR program, the
sources that could contribute to noncompliance with the SO2
NAAQS are well-defined and consist of large industrial sources already
subject to the permitting program. The ADEQ concluded, based on the
above considerations, that for purposes of minor NSR, use of the
Scenario 2 thresholds would not offer any substantial benefits over
Scenario 1, and set numerical exemption thresholds for the pollutants
in its minor NSR program that equate to one half of the PSD SERs.\26\
---------------------------------------------------------------------------

    \26\ See Appendix A of the ADEQ's 2012 NSR SIP submittal at
1547-1549 for a detailed discussion of the ADEQ's approach and
analysis. See also, the Technical Support Document for the EPA's
Notice of Proposed Rulemaking, Revision to the Arizona State
Implementation Plan for the Arizona Department of Environmental
Quality, March 2015 (``EPA's 2015 TSD'') at 22-25. The ADEQ's
``permitting exemption thresholds'' are found at R18-2-101(101). The
thresholds are ton per year values set for various pollutants that
determine when a permit or registration is required for new sources
and when minor NSR review is triggered for modifications. If
potential source-wide emissions from all regulated pollutants are
below the permitting exemption thresholds, then the source is
``exempt'' from the ADEQ's permitting and registration program.
---------------------------------------------------------------------------

    In response to the EPA's determination in our 2015 NSR action that
the ADEQ needed to justify the chosen permitting thresholds for
PM2.5 and to further justify the thresholds as they apply in
nonattainment areas, in its 2020 Minor NSR submittal, the ADEQ
continued to build on its prior analyses supporting the current
permitting thresholds in its minor NSR program.\27\ First, the ADEQ
updated its prior source distribution analysis to use the National
Emissions Inventory, the same data set that the EPA used for its
analysis for the Tribal Minor NSR program, and to include
PM2.5 emissions. The analysis shows that the ADEQ's NSR
program is expected to cover approximately 98% of PM2.5
emissions in counties where the ADEQ has minor source permitting
jurisdiction and approximately 96% of PM2.5 emissions in
PM2.5 nonattainment areas where the ADEQ has minor source
permitting jurisdiction. Further, the

ADEQ considered the types of emission sources in each of the
nonattainment areas where it has minor source permitting jurisdiction
that contribute to nonattainment. For example, the Hayden and Miami
SO2 nonattainment areas are attributable to the copper
smelters operating in each area, and the Nogales nonattainment area for
particular matter with an aerodynamic diameter less than or equal to 10
microns (``PM10'') is attributable to paved road dust,
construction, and residential wood burning. As we summarized in the TSD
for our December 23, 2020 proposed action, ``[t]his discussion shows
that minor sources are not currently significant contributors to the
nonattainment issues in these areas.'' \28\
---------------------------------------------------------------------------

    \27\ See 2020 Minor NSR submittal at 14-20 for the full
discussion.
    \28\ Technical Support Document for EPA's Notice of Proposed
Rulemaking: Air Plan Approval; Arizona; Stationary Sources; New
Source Review Updates, November 2020 (``EPA's 2020 TSD'') at 15.
---------------------------------------------------------------------------

    In consideration of the information summarized in this response, we
disagree with the commenters that the ADEQ's approach to revising its
minor source permitting thresholds for PM2.5 and in
designated nonattainment areas where it has minor source permitting
jurisdiction was arbitrary and unsupported. We find that the ADEQ has
provided sufficient evidence that its NSR program will apply to the
vast majority of emissions where the ADEQ has permitting jurisdiction,
including in Arizona's nonattainment areas, and including
PM2.5 emissions in attainment areas.\29\ As a result, we
conclude that those emissions exempted from the ADEQ's NSR program
under its minor NSR permitting exemption thresholds will be
inconsequential to attainment and maintenance of the NAAQS.
---------------------------------------------------------------------------

    \29\ The ADEQ's program requires permitting or registration for
new and existing sources. While a NAAQS review is generally only
triggered for new sources or modifications, the ADEQ's permitting of
existing sources provides additional protection that such sources
are also complying with all other applicable CAA requirements.
---------------------------------------------------------------------------

    While we agree with the commenters' general proposition that the
NSR program focuses on the review of new sources and modifications to
existing sources, we disagree that this means that the rationale and
analysis provided by the ADEQ to support its permitting exemption
thresholds is inadequate. The commenters have not suggested or provided
an alternative analysis that they believe would be appropriate to
demonstrate the insufficiency of the minor NSR thresholds at issue,
other than a generic reference to ``modeling.'' We find the ADEQ's
rationale persuasive and find that the ADEQ has demonstrated that the
permitting thresholds it has established by considering local
conditions will capture the types and sizes of sources that are
necessary for review to ensure such sources will not interfere with
attainment and maintenance of the NAAQS in the areas where the ADEQ has
minor NSR permitting jurisdiction.\30\ Thus, the additional analysis
and information provided by the ADEQ in the 2020 Minor NSR submittal is
sufficient for demonstrating that the permitting thresholds for minor
sources in nonattainment areas and minor sources of PM2.5 in
attainment areas meet the requirements of CAA section 110(l) and
Appendix V to 40 CFR part 51 \31\ and will not interfere with
attainment and maintenance of the NAAQS.
---------------------------------------------------------------------------

    \30\ The NSR program is only one aspect of the CAA requirements
that must be implemented to ensure attainment and maintenance of the
NAAQS. The NSR program is generally intended to allow for increases
in emissions if it can be demonstrated that the increases will not
interfere with attainment. Among other CAA programs, the
comprehensive set of requirements found in CAA title I, part D are
designed to ensure that State and local authorities with
jurisdiction over nonattainment areas require the necessary
reductions to reach attainment.
    \31\ As explained above, the commenters do not accurately
characterize the SIP submittal completeness criteria in Section
2.2(e) of Appendix V to 40 CFR part 51 as it relates to modeling. We
find that section 2.2(e) is not applicable to the 2020 Minor NSR
submittal because it did not contain modeling to support the SIP
revision, nor is modeling required in this instance.
---------------------------------------------------------------------------

    Comment: The commenters assert that the 2020 Minor NSR submittal
fails to demonstrate under 40 CFR 51.160(e) that review of
``agricultural equipment used in normal farm operations'' under the
ADEQ's minor NSR program is not needed for the ADEQ's program to meet
federal NSR requirements for attainment and maintenance of the NAAQS or
review for compliance with the control strategy. The commenters take
issue with several aspects of the ADEQ's rationale, that we discuss in
detail below, and further conclude that this exemption violates CAA
section 110(l) and sections 2.2(d) and (e) of Appendix V to 40 CFR part
51.
    Response: As discussed below, we respectfully disagree with the
commenters that the 2020 Minor NSR submittal does not demonstrate that
the State's exemption for ``agricultural equipment used in normal farm
operations'' in its NSR program is approvable under 40 CFR 51.160(e).
The ADEQ's submittal demonstrates that regulation of these exempt
sources under its minor NSR program is not needed for ADEQ's program to
meet federal NSR requirements for attainment and maintenance of the
NAAQS or review for compliance with the control strategy. As the ADEQ
has explained in detail, this exemption could potentially apply only to
a very narrow group of minor sources that would not otherwise be exempt
from minor NSR review under exemptions already approved by the EPA in
our 2015 NSR action. Further, the ADEQ retains authority to require a
permit even for the sources that will fit within this exemption if it
determines that doing so is necessary to protect the NAAQS or
enforcement of the control strategy. For these reasons, we also
disagree that the exemption violates CAA section 110(l) and section
2.2(d) of Appendix V to 40 CFR part 51.\32\
---------------------------------------------------------------------------

    \32\ As noted previously, the commenters do not accurately
characterize section 2.2(e) of Appendix V, which requires that SIP
submittals include certain information that supports modeling when
modeling is otherwise required to be conducted for a SIP revision.
The CAA does not require all SIP submittals to contain modeling, and
modeling was not included in or required to support the 2020 Minor
NSR submittal. Therefore, we continue to find that section 2.2(e) of
Appendix V is not applicable to the 2020 Minor NSR submittal in
general, nor does it apply specifically to the ADEQ's demonstration
supporting the exemption of agricultural equipment used in normal
farm operations.
---------------------------------------------------------------------------

    The State of Arizona exempts ``agricultural equipment used in
normal farm operations'' from the general requirement to obtain an air
permit.\33\ The ADEQ's permitting regulations implement this exemption
by exempting ``agricultural equipment used in normal farm operations''
from the requirement to obtain a registration or permit at R18-2-
302(C). R18-2-302(C) makes clear that this exemption does not apply if
the source is a ``major source'' or if ``operation without a permit
would result in a violation of the [Clean Air] Act.'' R18-2-302(C)(2)
also clarifies that ``agricultural equipment used in normal farm
operations'' does not include equipment classified as a source that
requires a permit under title V of the Act or that is subject to a
standard under 40 CFR parts 60, 61, or 63.
---------------------------------------------------------------------------

    \33\ See ARS 49-426(B), which states, in part, in reference to
the State law requirements for obtaining air permits: ``The
provisions of this section shall not apply to motor vehicles, to
agricultural vehicles or agricultural equipment used in normal farm
operations, or to fuel burning equipment which, at a location or
property other than a one or two family residence, is rated at less
than one million British thermal units per hour.'' (emphasis added)
---------------------------------------------------------------------------

    We identified this exemption as one of the bases for our limited
disapproval of the ADEQ's 2012 NSR SIP submittal in our 2015 NSR action
because the submittal did not adequately justify the exemption as
required by 40 CFR 51.160(e),\34\ and it was unclear how the

exemption in state law applied in the context of the ADEQ's NSR
program.\35\ In response to this limited disapproval, the ADEQ provided
a detailed discussion of the exemption in the 2020 Minor NSR submittal.
As summarized below, the ADEQ's 2020 Minor NSR submittal demonstrates
that the exemption is only available to a limited set of minor sources
not otherwise exempt under exemptions we have already approved into the
Arizona SIP as part of the ADEQ's NSR program, and the program's
potential exemption of such sources would be inconsequential to
attainment and maintenance of the NAAQS.
---------------------------------------------------------------------------

    \34\ See 40 CFR 51.160(e): ``The procedures must identify types
and sizes of facilities, buildings, structures, or installations
which will be subject to review under this section. The plan must
discuss the basis for determining which facilities will be subject
to review.''
    \35\ See section <IP_ADDRESS> of the EPA's 2015 TSD at 26-27 and 80
FR 67319, 67323.
---------------------------------------------------------------------------

    First, the 2020 Minor NSR submittal clarified that the exemption at
R18-2-302(C) represents the ADEQ's interpretation of the agricultural
exemption in Arizona Revised Statutes (ARS) section 49-426(B):

    This rule represents ADEQ's official implementation and
interpretation of the statutory exemption under its rulemaking
authority in ARS Sec. Sec.  49-425 and 49-426(B). The rule has been
recognized as valid by the Arizona Attorney General in its opinion
supporting the state's Title V program in 1993.\36\ In approving
Arizona's Title V program in 1996, EPA deferred to this opinion but
stated that it would revisit this issue if ``a successful legal
challenge to [the regulatory exemption] occurs.'' \37\ In the
subsequent 23 years, there has been no such challenge.
---------------------------------------------------------------------------

    \36\ Attorney General's Opinion, 2 (Nov. 15, 1993), Appendix D
of the 2020 Minor NSR submittal.
    \37\ 61 FR 55910, 55915 (Oct. 30, 1996).

Section 4.2.1 of the 2020 Minor NSR submittal at 10.
    Second, the ADEQ confirmed that the ADEQ interprets its permitting
requirements such that its permitting determinations (including for the
registration program component of its minor NSR program) are made on a
source-wide basis. As a result, if ``agricultural equipment used in
normal farm operations'' is located at the same stationary source as
equipment that requires a permit, then the ADEQ's permit requirements,
and potentially NSR, extend to the entire source and all of its
pollutant-generating activities, including any equipment that might
otherwise meet the definition of ``agricultural equipment used in
normal farm operations''. These two clarifications mean that the
agricultural equipment exemption is potentially available only to a
subset of minor sources. See section 4.2.2 of the 2020 Minor NSR
submittal at 10-11.
    While the term ``normal farm operations'' is not specifically
defined by statute or rule, the ADEQ stated that the State of Arizona's
Agricultural Best Management Practices (Ag BMP) program for commercial
farming operations in PM10 nonattainment areas provides
guidance on the State's interpretation of the types of activities that
constitute normal farm operations. This includes activities such as
tillage, planting, and harvesting; areas of a commercial farm that are
not normally in crop production (i.e., fallow); areas of a commercial
farm that are normally in crop production; significant agricultural
earthmoving activities; traffic over unpaved access connections or
unpaved roads or feed lanes; animal waste handling and transporting;
arenas, corrals, and pens; and canals. The ADEQ stated that it
interprets the normal farm operations exemption as applicable to the
types of equipment used for these activities and to crop and feed
processing equipment that produces only fugitive emissions. In the
ADEQ's experience, farm emissions tend to consist almost exclusively of
fugitive dust generated by the disturbance of soils. It is important to
note that the ADEQ's current SIP-approved NSR program already exempts
fugitive emissions,\38\ at R18-2-302(F), in determining whether a
stationary source is subject to minor NSR permitting requirements. See
sections 4.2.3 and 4.2.4 of the 2020 Minor NSR submittal at 11-12.\39\
As a result, most of the sources that would meet the definition of
``agricultural equipment used in normal farm operations'' would be
sources of fugitive emissions that are already exempt from minor NSR
under the ADEQ's SIP-approved minor NSR program.
---------------------------------------------------------------------------

    \38\ Fugitive emissions are defined in the ADEQ's SIP-approved
regulations at R18-2-101(59) as ``those emissions which could not
reasonably pass through a stack, chimney, vent, or other
functionally equivalent opening.'' See section 4.2 of the 2020 Minor
NSR submittal at 9, n.14.
    \39\ See also 80 FR 67319, 67320, Table 1.
---------------------------------------------------------------------------

    The ADEQ also recognized that it is possible for equipment used in
normal farm operations to be a part of a stationary source that
produces stack (i.e., non-fugitive) emissions greater than the ADEQ's
permitting exemption thresholds, and it may also be possible for normal
farm operations themselves to be configured in such a way as to produce
stack emissions. However, the ADEQ believes that, in most cases, such a
stationary source would not qualify for the permitting exemption
because equipment used in normal farm operations ``does not include
equipment classified as a source that requires a permit under Title V
of the Act, or that is subject to a standard under 40 CFR 60, 61, or
63.'' Because the ADEQ determines permit applicability on a source-wide
basis, if a stationary source that engaged in normal farm operations
qualified as a CAA title V source or included equipment subject to a
New Source Performance Standard (NSPS) or National Emission Standard
for Hazardous Air Pollutants (NESHAP) in 40 CFR parts 60, 61, or 63,
then the entire source would require a permit, and potentially be
subject to minor NSR if its emissions were above the ADEQ's minor NSR
permitting exemption thresholds. In the ADEQ's experience, most
permitted sources include one or more pieces of equipment subject to an
NSPS, such as a boiler, stationary engine, or fuel storage tank. The
ADEQ concluded that it is likely that if equipment used in normal farm
operations were collocated with equipment with stack emissions
exceeding the permitting exemption thresholds, at least some of that
equipment would be subject to an NSPS, and therefore the normal farm
operations exemption would not apply. See section 4.2.5 of the 2020
Minor NSR submittal at 12-13.
    Finally, the ADEQ explained that under R18-2-302(C), equipment used
in normal farm operations is not exempt if ``operation [of the
equipment] without a permit would result in a violation of the Act,''
which provides a final safeguard for its NSR program. In a situation
where agricultural equipment used in normal farm operations with stack
emissions above the permitting exemption thresholds used the exemption
to avoid permitting, the ADEQ would invoke this provision as necessary
to ensure that any such source does not endanger attainment or
maintenance of the NAAQS or enforcement of the control strategy. The
ADEQ explained that whenever it becomes aware of such a source through
citizen complaint, inspection of the facility under the Ag BMP program,
inspection of a nearby or related facility, notice from a building
permit agency, or other means, the ADEQ will evaluate the facility
using the methodology in R18-2-302.01(C) to determine whether it should
be subject to permitting and minor NSR. See section 4.2.5 of the 2020
Minor NSR submittal at 13.
    In our proposed action, we found that the ADEQ had demonstrated
that its exemption for agricultural equipment used in normal farm
operations is extremely limited in scope, and the potential sources
exempted from permitting would be inconsequential to attainment and
maintenance of the

NAAQS. We stated that our determination was based on the ADEQ's
interpretation of the narrow manner in which the exemption applies, the
limited types of operations that are considered to be ``normal farm
operations,'' and the ADEQ's retention of authority to address any
potentially exempt sources that may endanger attainment or maintenance
of the NAAQS or enforcement of the control strategy. We agreed that the
vast majority of these operations are likely already exempted from the
ADEQ's SIP-approved minor NSR program under the general exemption for
excluding fugitive emissions in permitting applicability
determinations. We concluded that the ADEQ's basis and explanation for
the exemption from minor NSR review for agricultural equipment used in
normal farm operations was acceptable.\40\
---------------------------------------------------------------------------

    \40\ 85 FR 83868, 83873.
---------------------------------------------------------------------------

    The commenters question certain aspects of the ADEQ's explanation
and the EPA's rationale for approving the agricultural exemption as
described above. First, the commenters disagree with the ADEQ's
explanation of the permit exemption not being applicable to sources
that are subject to a standard under 40 CFR parts 60, 61, or 63 or that
are title V sources. The commenters do not see how this interpretation,
which they say results in a ``blanket'' exemption for minor sources
from permitting, is protective of the NAAQS. In response, this
explanation simply clarifies the scope of the exemption by confirming
that major sources and sources subject to a standard under 40 CFR parts
60, 61, or 63 cannot use the exemption. We disagree with the commenters
that this interpretation by the ADEQ results in a ``blanket'' exemption
for minor sources. Among other things, we note that sources that are
subject to a standard under 40 CFR parts 60, 61, or 63 are often minor
sources. The ADEQ has clarified that if any aspect of a stationary
source is subject to one of these federal standards, then the entire
stationary source, including any ``agricultural equipment used in
normal farm operations,'' becomes subject to the ADEQ's permitting
program.\41\
---------------------------------------------------------------------------

    \41\ The commenters also state that ``the fact that no one has
challenged [R18-2-302(C)] does not mean a challenge could not occur
in the future.'' This concern appears to address the ADEQ's
reference to the fact that the Arizona Attorney General issued an
opinion recognizing the validity of this exemption in support of the
State's Title V program in 1993. See section 4.2.1 of the 2020 Minor
NSR submittal at 10. As the ADEQ explained, the EPA stated in 1996
that it would defer to this opinion of the Arizona Attorney General
in the absence of a successful legal challenge to the regulation.
The commenters did not otherwise explain how this concern affects
the approvability of the 2020 Minor NSR submittal.
---------------------------------------------------------------------------

    Second, the commenters take issue with the ADEQ's explanation that
it expects the overwhelming majority of emissions from ``agricultural
equipment used in normal farm operations'' to be fugitive emissions.
The commenters assert that the fact that most of these exempted
emissions are expected to be fugitive does not explain how the
exemption is protective of the NAAQS. In response, it is important to
understand the context for this explanation from the ADEQ. In our 2015
NSR action, as part of our limited approval and limited disapproval of
the ADEQ's NSR program, the EPA approved of the ADEQ minor NSR
program's treatment of fugitive emissions in determining when a permit
is required. The ADEQ's minor NSR program requires fugitive emissions
to be included in permit applicability determinations for certain
industrial source categories listed in R18-2-101(23), such as Portland
cement plants, primary lead smelters, primary copper smelters, and
fossil-fuel-fired steam electric plants; and for sources which, as of
August 7, 1980, were being regulated under section 111 or 112 of the
Act. Fugitive emissions are not included in permit applicability
determinations for any other minor sources; however, fugitive emissions
are reviewed in minor NSR permit actions for any source triggering
review because of non-fugitive emissions. See R18-2-101(12), R18-2-
101(128), and R18-2-302(F). In our 2015 NSR action, we approved the
ADEQ's minor NSR program under 40 CFR 51.160(e), including its
treatment of sources of fugitive emissions, with the exception of the
specific limited disapproval issues that we identified and that the
ADEQ is addressing in the 2020 Minor NSR submittal. See section <IP_ADDRESS>
of the EPA's 2015 TSD at 26-27; 80 FR 67319, 67323, 67332. In its 2020
Minor NSR submittal, the ADEQ is clarifying that the overwhelming
majority of sources that could potentially use the agricultural
equipment permit exemption are fugitive emissions sources that the EPA
already approved for exemption from determining whether a permit is
required, in our 2015 action. As a result, the agricultural equipment
exemption does not create an additional large category of sources
exempt from minor NSR permitting.
    The commenters, however, further argue that fugitive dust emissions
from agricultural equipment are primarily addressed through the State's
Ag BMP program, and that ``experience with the Ag BMP program in both
Maricopa County and Pinal County has demonstrated that it is wholly
inadequate to ensure compliance with the PM10 NAAQS.'' The
commenters are concerned that the two PM10 nonattainment
areas in Maricopa and Pinal counties continue to violate the NAAQS
despite the adoption of the Ag BMP program. The commenters point to
recent exceedances of the PM10 NAAQS in the Phoenix planning
area (which covers portions of Maricopa and Pinal counties) and the
fact that the West Pinal nonattainment area did not attain the
PM10 standard by the attainment date and was recently
reclassified to serious nonattainment for PM10. While the
nonattainment issues in these areas are concerning, it is important to
recognize that the Maricopa County Air Quality Department and Pinal
County Air Quality Control District, rather than the ADEQ, have
original jurisdiction for permitting minor sources in these areas of
Arizona,\42\ thus the ADEQ's minor NSR program would generally be
inapplicable in these areas. Given that the ADEQ's minor NSR program
does not generally extend to sources in the Phoenix and West Pinal
PM10 nonattainment areas, the commenters' concerns about the
use of the Ag BMP program to address fugitive dust in the Phoenix and
West Pinal PM10 nonattainment areas do not indicate that the
ADEQ's regulation of exempt agricultural equipment used in normal farm
operations in other areas that are within the ADEQ's minor NSR
permitting jurisdiction is necessary for attainment and maintenance of
the NAAQS.\43\
---------------------------------------------------------------------------

    \42\ See the ADEQ's July 2, 2014 supplement to the 2012 NSR SIP
submittal at 8-9.
    \43\ We note that the commenters' general concerns about the
sufficiency of the Arizona Ag BMP program in the Phoenix and West
Pinal PM10 nonattainment areas are outside the scope of
this action on revisions to the ADEQ's minor NSR program.
---------------------------------------------------------------------------

    Third, the commenters question the ADEQ's statement that ``[i]n the
overwhelming majority of the remaining cases, equipment used in normal
farm operations will be located at a stationary source that either
qualifies as a title V source or includes equipment subject to a new
source performance standard (NSPS)''. The commenters believe that the
ADEQ has not supported this claim. The commenters are also concerned
because they claim that the NSPS standards do not apply during periods
of startup, shutdown, and malfunction, while the NAAQS apply at all
times. We disagree that the ADEQ did not support this claim. Section
4.2.5 of the 2020 Minor NSR submittal provides the

ADEQ's rationale.\44\ For example, the submittal explains that, in the
ADEQ's experience, most permitted sources include one or more pieces of
equipment subject to an NSPS, such as boilers, stationary engines, or
fuel storage tanks. The ADEQ clarified that a stationary source subject
to such a standard could not make use of the agricultural equipment
exemption.
---------------------------------------------------------------------------

    \44\ 2020 Minor NSR submittal at 12-13.
---------------------------------------------------------------------------

    The ADEQ's submittal further explains that under section 111 of the
Clean Air Act, EPA is required to maintain a list of, and adopt NSPS
for, all categories of sources that cause or significantly contribute
to ``air pollution which may reasonably be anticipated to endanger
public health or welfare.'' The ADEQ notes that, consistent with the
breadth of this charge, the EPA has adopted standards for dozens of
common sources of criteria pollutants, criteria pollutant precursors,
greenhouse gases, and other pollutants. The ADEQ reasons that it is
therefore likely that if equipment used in normal farm operations were
collocated with equipment with stack emissions exceeding the permitting
exemption thresholds, at least some of that equipment would be subject
to an NSPS, and the exemption would not apply.\45\
---------------------------------------------------------------------------

    \45\ Section 4.2.5 of the 2020 Minor NSR submittal at 12; see
also the detailed discussion in section 4.2.5 of the 2020 Minor NSR
submittal at 12-13.
---------------------------------------------------------------------------

    We believe the ADEQ's explanation to be sufficiently supported
based on the ADEQ's knowledge and experience with the pollutant-
generating activities it oversees.\46\
---------------------------------------------------------------------------

    \46\ On the issue of the NSPS standards not applying during
periods of startup, shutdown, or malfunction (we disagree with this
broad categorization), while the NAAQS do, we believe the commenters
misunderstand how the ADEQ's permitting program works and how the
normal farm operations exemption would apply to a source that
includes equipment subject to an NSPS. The ADEQ does not allow
stationary sources to use the agricultural equipment exemption to
avoid NSR review if the stationary source is also subject to a
standard under 40 CFR parts 60, 61, or 63. This means that the
entire stationary source becomes subject to the ADEQ's permitting
program, including potential NAAQS reviews for new or modified
sources, if even a single piece of equipment is subject to an NSPS.
The way the various NSPS apply in general during periods of startup,
shutdown, or malfunction is not germane to the scope of the normal
farm operations exemption.
---------------------------------------------------------------------------

    Finally, the commenters challenge the ADEQ's statement that ``[i]n
the few, if any, cases where equipment used in normal farm operations
is located at a non-title V source that has stack emissions above the
permitting exemption thresholds but does not include NSPS or NESHAP
equipment, ADEQ retains the authority to require a permit to the extent
necessary to assure protection of the NAAQS and the control strategy.''
\47\ The commenters express concern because they are unclear on how the
ADEQ would know that a permit is needed or that there is a potential
NAAQS issue if sources aren't required to submit applications for
review. We understand the commenters' concern on this issue, because
the NSR program is intended to require review of sources prior to
construction or modification to ensure that sources and modifications
are constructed in a manner that will not cause or contribute to a
NAAQS violation. However, our approval of the ADEQ's agricultural
equipment exemption under 40 CFR 51.160(e) is based on the totality of
the information presented by the ADEQ in the 2020 Minor NSR submittal.
The ADEQ has demonstrated that the exemption creates a narrow category
of sources that may be exempt from minor NSR review, as compared to the
program we have already approved. However, in the potential instances
where a stationary source is otherwise not required to obtain a permit
in advance, the ADEQ has clarified that it has the authority to later
require a permit and limit operations to protect the NAAQS. That is,
minor sources defined as agricultural equipment used in normal farm
operations cannot operate in a manner that would interfere with
attainment and maintenance of the NAAQS by relying on the permitting
exemption in State law.
---------------------------------------------------------------------------

    \47\ 2020 Minor NSR submittal at 9.
---------------------------------------------------------------------------

    In sum, the ADEQ has provided a detailed and well-supported
rationale for its exemption of ``agricultural equipment used in normal
farm operations'' from its minor NSR program, and demonstrated that any
potentially exempted sources are inconsequential to attainment and
maintenance of the NAAQS. Further, because the exemption will not
interfere with the NAAQS, it is consistent with CAA section 110(l) and
section 2.2(d) of Appendix V to 40 CFR part 51.
    Comment: The commenters state that the ADEQ failed to justify the
exemption for certain small stationary fuel burning equipment rated at
less than one million British thermal units per hour (MMBtu/hr) found
in Arizona state law. The commenters are concerned that the ADEQ's
rationale does not justify the exemption or ensure protection of the
NAAQS, as the ADEQ did not present modeling or other evidence in
support of the exemption or to support that this equipment would not
otherwise require a permit.
    Response: We disagree with the commenters that the ADEQ has not
adequately justified the Arizona state law exemption for small fuel
burning equipment (those rated at less than 1 MMBtu/hr) in ARS section
49-426(B) within the context of its NSR program. The ADEQ's 2020 Minor
NSR submittal provides an analysis of the state law exemption because
the EPA identified it as a limited disapproval issue in our 2015 NSR
action. In our 2015 NSR action, we found that the ADEQ's 2012 NSR
submittal did not describe how the state law exemption for small fuel
burning equipment applied in the context of its NSR program. Further,
to the extent the ADEQ's NSR program exempts some sources from minor
NSR review under the state law exemption, we found that the ADEQ needed
to provide an adequate justification under 40 CFR 51.160(e).\48\
---------------------------------------------------------------------------

    \48\ See section <IP_ADDRESS> of the EPA's 2015 TSD at 26-27; 80 FR
67319, 67323.
---------------------------------------------------------------------------

    In the 2020 Minor NSR submittal, the ADEQ confirmed that it
interprets the exemption as (1) being available only to those
stationary sources that consists ``solely of equipment with a
cumulative heat input rate'' of less than 1 MMBtu/hr, and (2) having
already been effectively SIP-approved by the EPA because all such
equipment falls under the ADEQ's existing SIP-approved exemption for
``categorically exempt activities'' at R18-2-302(C)(1) and R18-2-
101(23).\49\
---------------------------------------------------------------------------

    \49\ See section 4.3 of the 2020 Minor NSR submittal at 13-14.
---------------------------------------------------------------------------

    As explained by the ADEQ in the 2020 Minor NSR submittal, the EPA
reviewed the ADEQ's permitting and registration exemption for
``categorically exempt activities'' in our 2015 NSR action. R18-2-
302(C) provides that a stationary source that consists solely of a
single ``categorically exempt activity'' plus any combination of
trivial activities \50\ does not require a permit or registration,
unless the source is a major source or operation without a permit would
result in a violation of the Act. The ADEQ defines a ``categorially
exempt activity'' at R18-2-101(24) and it includes various categories
of smaller fuel-burning equipment. For example, one category is ``any
combination of diesel-, natural gas- or gasoline-fired engines with
cumulative power equal to or less than 145 horsepower'' and another is
``any combination of boilers with a cumulative maximum design heat
input capacity of less than 10 million Btu/hr.'' The ADEQ explained in
its 2012 NSR SIP submittal how the cumulative heat input or power
rating

for each category of equipment was determined by estimating the worst-
case potential emissions for the category and ensuring that such
emissions would be below the ADEQ's permitting exemption
thresholds.\51\ With this clarification, we approved of the
``categorically exempt activities'' in the 2015 NSR action.\52\ To
illustrate this concept, the 2020 Minor NSR submittal also contains a
sample calculation for a boiler burning No. 6 fuel oil with a heat
input rating of 10 MMBtu/hr. The sample calculation shows that
potential emissions of NOX from such equipment would be 16.1
tons per year and below the ADEQ's 20 tpy minor NSR permitting
exemption threshold for NOX. Accordingly, the smaller fuel-
burning equipment, rated less than 1 MMBtu/hr, that is exempt under ARS
section 49-426(B) would have emissions well below the ADEQ's approved
permitting exemption thresholds, and therefore would not otherwise
require a permit or registration under the ADEQ's program. The ADEQ
explains that the purpose of the exemption for categorically exempt
activities is to allow such low-emitting small fuel-burning
installations, which would not in any case require a permit, to avoid
having to perform unnecessary emissions calculations.\53\
---------------------------------------------------------------------------

    \50\ Trivial activities under the ADEQ's permitting program are
defined R18-2-101(146).
    \51\ See Appendix A to the 2012 NSR SIP submittal at 1570 and
1571.
    \52\ EPA's 2015 TSD at 25.
    \53\ Section 4.3 of 2020 Minor NSR submittal at 13-14.
---------------------------------------------------------------------------

    Given the rationale provided by the ADEQ, and our prior review and
approval under 40 CFR 51.160(e) of the ADEQ's exemption of
``categorically exempt activities'' under its minor NSR program, we
disagree with the commenters that the ADEQ has not adequately justified
the state law exemption.\54\ The ADEQ has demonstrated that fuel
burning equipment rated less than 1 MMBtu/hr is equipment that falls
within the existing SIP-approved category of ``categorically exempt
activities,'' and also that it is equipment that would otherwise not
require a permit or registration compared to the ADEQ's approved \55\
permitting thresholds. In sum, the state law exemption for small
fueling burning equipment has previously been determined by the EPA to
be inconsequential to attainment and maintenance of the NAAQS, and the
commenters have not provided information demonstrating why they believe
this exemption is not protective of the NAAQS, or otherwise provided
information that calls into question our previous approval of the
ADEQ's exemption for categorically exempt activities under 40 CFR
51.160(e).
---------------------------------------------------------------------------

    \54\ The commenters specifically identified ``modeling'' as an
example of the type of evidence to support this exemption. Modeling
was not required to make this demonstration.
    \55\ In our 2015 NSR action, we approved of the ADEQ's
``permitting exemption thresholds'' for each regulated pollutant,
except PM2.5, and our approval of the thresholds was
limited to their application in attainment areas. With today's
action, we are now also approving the thresholds as they apply to
PM2.5 and nonattainment areas.
---------------------------------------------------------------------------

    Comment: The ADEQ states that its NSR program applies to the areas
of the State where the ADEQ has permitting jurisdiction (all counties
in Arizona other than Maricopa, Pima, and Pinal, except where the ADEQ
asserts jurisdiction). The commenters state that the ADEQ should
explain whether the minor NSR programs in Maricopa, Pima, and Pinal
counties are SIP-approved and meet all CAA requirements. To the extent
they do not, the ADEQ should fix any deficiencies with the 2020 Minor
NSR submittal.
    Response: As the commenters note, the 2020 Minor NSR submittal, and
the requirements therein relating to the ADEQ's minor NSR permitting
program, are applicable only to those portions of the Arizona SIP where
the ADEQ has minor NSR permitting jurisdiction. The EPA reviewed the
ADEQ's submitted SIP revision and determined that it complies with all
relevant CAA requirements for approval into the Arizona SIP. In
addition, this revision will correct several outstanding deficiencies
in the ADEQ's minor NSR program that were previously identified by the
EPA. The commenters' questions about the sufficiency of the minor NSR
permitting programs for other areas and sources within Arizona that are
within the jurisdiction of Maricopa, Pima, and Pinal counties, and
which are not covered by ADEQ's minor NSR program, are not germane to
the EPA's current SIP action on the 2020 Minor NSR submittal. The CAA
does not require that the ADEQ (or the EPA) address all components of
the minor NSR program implemented by all permitting authorities in
Arizona in any particular SIP action.

III. EPA Action

    No comments changed our assessment of our proposed action.
Therefore, as authorized in section 110(k)(3) of the Act, the EPA is
approving the ADEQ's 2019-20 NSR submittals, specifically including the
2020 Minor NSR submittal and the Ammonia PM2.5 NSR
submittal. We find that the ADEQ has corrected all remaining
deficiencies identified as the bases for our final limited disapproval
of the ADEQ's NSR program in our 2015 NSR action and the basis for our
conditional approval of the ADEQ's NNSR program in our 2018 Major NSR
action. Thus, the issues that formed the basis for our final limited
disapproval in 2015 of the ADEQ's minor NSR, PSD, and NNSR programs and
our conditional approval in 2018 of the ADEQ's NNSR program are now
fully resolved. Our final action updates the ADEQ's SIP-approved NSR
program, corrects previously identified deficiencies, and recognizes
that the ADEQ's NSR program also satisfies the CAA visibility
requirements in 40 CFR 51.307. Additionally, the sanctions and
sanctions clocks triggered by our 2016 PM2.5 precursor
action for the West Pinal and Nogales PM2.5 nonattainment
areas will be permanently terminated on the effective date of this
final approval action.
    This action approves the rules listed in Table 1 of this notice
into the ADEQ portion of the Arizona SIP and removes or supersedes the
rules listed in Table 2 of this notice from the ADEQ portion of the
Arizona SIP. We are also revising 40 CFR 52.119 to remove the
conditional approval of the State's plan related to ammonia as a
PM2.5 precursor, as we are now fully approving this
component of the State's plan. Finally, in conjunction with the EPA's
SIP approval of the ADEQ's visibility program for sources subject to
the ADEQ's PSD and NNSR programs, we are revising 40 CFR 52.145(b) to
remove the visibility FIP at 40 CFR 52.27, as well as the visibility
FIP at 40 CFR 52.28 for those stationary sources subject to the ADEQ's
permitting jurisdiction, as these FIPs are no longer applicable.

IV. Incorporation by Reference

    In this rule, the EPA is finalizing regulatory text that includes
incorporation by reference. In accordance with requirements of 1 CFR
51.5, the EPA is finalizing the incorporation by reference of the ADEQ
rules described in the amendments to 40 CFR part 52 set forth below.
Therefore, these materials have been approved by the EPA for inclusion
in the SIP, have been incorporated by reference by the EPA into that
plan, are fully federally enforceable under sections 110 and 113 of the
CAA as of the effective date of the final rulemaking of the EPA's
approval, and will be incorporated by reference in the next update to
the SIP compilation.\56\ The EPA has made, and will continue to make,
these documents available through https://www.regulations.gov and at
the EPA Region IX Office (please contact the person identified in the
FOR FURTHER

INFORMATION CONTACT section of this preamble for more information).
---------------------------------------------------------------------------

    \56\ 62 FR 27968 (May 22, 1997).
---------------------------------------------------------------------------

    Also in this document, as described in the amendments to 40 CFR
part 52 set forth below, the EPA is removing provisions from the EPA-
approved rules for the ADEQ portion of the Arizona SIP, which is
incorporated by reference in accordance with the requirements of 1 CFR
part 51.

V. Statutory and Executive Order Reviews

    Under the CAA, the Administrator is required to approve a SIP
submission that complies with the provisions of the Act and applicable
federal regulations. 42 U.S.C. 7410(k); 40 CFR 52.02(a). Thus, in
reviewing SIP submissions, the EPA's role is to approve state choices,
provided that they meet the criteria of the Act. Accordingly, this
proposed action merely proposes to approve state law as meeting federal
requirements and does not impose additional requirements beyond those
imposed by state law. For that reason, this proposed action:
     Is not a ``significant regulatory action'' subject to
review by the Office of Management and Budget under Executive Orders
12866 (58 FR 51735, October 4, 1993) and 13563 (76 FR 3821, January 21,
2011);
     Is not an Executive Order 13771 (82 FR 9339, February 3,
2017) regulatory action because SIP approvals are exempted under
Executive Order 12866;
     Does not impose an information collection burden under the
provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
     Is certified as not having a significant economic impact
on a substantial number of small entities under the Regulatory
Flexibility Act (5 U.S.C. 601 et seq.);
     Does not contain any unfunded mandate or significantly or
uniquely affect small governments, as described in the Unfunded
Mandates Reform Act of 1995 (Pub. L. 104-4);
     Does not have federalism implications as specified in
Executive Order 13132 (64 FR 43255, August 10, 1999);
     Is not an economically significant regulatory action based
on health or safety risks subject to Executive Order 13045 (62 FR
19885, April 23, 1997);
     Is not a significant regulatory action subject to
Executive Order 13211 (66 FR 28355, May 22, 2001);
     Is not subject to requirements of section 12(d) of the
National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272
note) because application of those requirements would be inconsistent
with the CAA; and
     Does not provide the EPA with the discretionary authority
to address disproportionate human health or environmental effects with
practical, appropriate, and legally permissible methods under Executive
Order 12898 (59 FR 7629, February 16, 1994).
    In addition, the SIP is not approved to apply on any Indian
reservation land or in any other area where the EPA or an Indian tribe
has demonstrated that a tribe has jurisdiction. In those areas of
Indian country, the rule does not have tribal implications and will not
impose substantial direct costs on tribal governments or preempt tribal
law as specified by Executive Order 13175 (65 FR 67249, November 9,
2000).

List of Subjects in 40 CFR Part 52

    Environmental protection, Air pollution control, Carbon monoxide,
Incorporation by reference, Intergovernmental relations, Nitrogen
dioxide, Ozone, Particulate matter, Sulfur dioxide, Reporting and
recordkeeping requirements, Volatile organic compounds.

    Authority:  42 U.S.C. 7401 et seq.

    Dated: June 8, 2021.
Deborah Jordan,
Acting Regional Administrator, Region IX.

    Accordingly, EPA amends Part 52, Chapter I, Title 40 of the Code of
Federal Regulations as follows:

PART 52--APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS

0
1. The authority citation for part 52 continues to read as follows:

    Authority:  42 U.S.C. 7401 et seq.

Subpart D--Arizona

Sec.  52.119   [Amended]

0
2. In Sec.  52.119, remove and reserve paragraph (a).

0
3. In Sec.  52.120, paragraph (c), Table 2 is amended:
0
a. Under the heading ``Title 9, Chapter 3'', by removing the center
heading ``Article 2'' and the entry for ``R9-3-217, paragraph A'';
0
b. Under the heading ``Title 18, Chapter 2, Article 1 (General)'', by
revising the entry for ``R18-2-101 (except 20)'';
0
c. Under heading ``Title 18, Chapter 2, Article 3 (Permits and Permit
Revisions)'', by:
0
i. Revising the entries for ``R18-2-301,'' ``R18-2-302,'' ``R18-2-
302.01,'' ``R18-2-304,'' ``R18-2-306,'' ``R18-2-306.01'';
0
ii. Adding, in numerical order, entries for ``R18-2-317,' ``R18-2-
317.01,'' and ``R18-2-317.02''; and
0
iii. Revising the entries for ``R18-2-319,'' ``R18-2-320,'' and ``R18-
2-334''; and
0
d. Under the heading ``Title 18, Chapter 2, Article 4 (Permit
Requirements for New Major Sources and Major Modifications to Existing
Major Sources)'', by revising the entry for ``R18-2-406.''
    The additions and revisions read as follows:

Sec.  52.120  Identification of plan.

* * * * *
    (c) * * *

                                    Table 2--EPA-Approved Arizona Regulations
----------------------------------------------------------------------------------------------------------------
                                                                                Additional
       State citation          Title/subject       State effective date     EPA approval date     explanation
----------------------------------------------------------------------------------------------------------------

                                                  * * * * * * *
----------------------------------------------------------------------------------------------------------------
                                               Article 1 (General)
----------------------------------------------------------------------------------------------------------------
R18-2-101 (except 20)......  Definitions......  February 1, 2020..........  [INSERT Federal    Submitted on July
                                                                             Register           22, 2020.
                                                                             CITATION], June
                                                                             16, 2021.

                                                  * * * * * * *
----------------------------------------------------------------------------------------------------------------
                                    Article 3 (Permits and Permit Revisions)
----------------------------------------------------------------------------------------------------------------
R18-2-301..................  Definitions......  February 1, 2020..........  [INSERT Federal    Submitted on July
                                                                             Register           22, 2020.
                                                                             CITATION], June
                                                                             16, 2021.
R18-2-302..................  Applicability;     March 21, 2017............  [INSERT Federal    Submitted on July
                              Registration;                                  Register           22, 2020.
                              Classes of                                     CITATION], June
                              Permits.                                       16, 2021.
R18-2-302.01...............  Source             February 1, 2020..........  [INSERT Federal    Submitted on July
                              Registration                                   Register           22, 2020.
                              Requirements.                                  CITATION], June
                                                                             16, 2021.

                                                  * * * * * * *
R18-2-304..................  Permit             February 1, 2020..........  [INSERT Federal    Submitted on July
                              Application                                    Register           22, 2020.
                              Processing                                     CITATION], June
                              Procedures.                                    16, 2021.
R18-2-306..................  Permit Contents..  March 21, 2017............  [INSERT Federal    Submitted on July
                                                                             Register           22, 2020.
                                                                             CITATION], June
                                                                             16, 2021.
R18-2-306.01...............  Permits            March 21, 2017............  [INSERT Federal    Submitted on July
                              Containing                                     Register           22, 2020.
                              Voluntarily                                    CITATION], June
                              Accepted                                       16, 2021.
                              Emission
                              Limitations and
                              Standards.

                                                  * * * * * * *
R18-2-317..................  Facility Changes   August 7, 2012............  [INSERT Federal    Submitted on July
                              Allowed Without                                Register           22, 2020.
                              Permit                                         CITATION], June
                              Revisions--Class                               16, 2021.
                              I.
R18-2-317.01...............  Facility Changes   August 7, 2012............  [INSERT Federal    Submitted on July
                              that Require a                                 Register           22, 2020.
                              Permit Revision--                              CITATION], June
                              Class II.                                      16, 2021.
R18-2-317.02...............  Procedures for     August 7, 2012............  [INSERT Federal    Submitted on July
                              Certain Changes                                Register           22, 2020.
                              that Do Not                                    CITATION], June
                              Require a Permit                               16, 2021.
                              Revision--Class
                              II.
R18-2-319..................  Minor Permit       March 21, 2017............  [INSERT Federal    Submitted on July
                              Revisions.                                     Register           22, 2020.
                                                                             CITATION], June
                                                                             16, 2021.
R18-2-320..................  Significant        March 21, 2017............  [INSERT Federal    Submitted on July
                              Permit Revisions.                              Register           22, 2020.
                                                                             CITATION], June
                                                                             16, 2021.

                                                  * * * * * * *
R18-2-334..................  Minor New Source   February 1, 2020..........  [INSERT Federal    Submitted on July
                              Review.                                        Register           22, 2020.
                                                                             CITATION], June
                                                                             16, 2021.
----------------------------------------------------------------------------------------------------------------
     Article 4 (Permit Requirements for New Major Sources and Major Modifications to Existing Major Sources)
----------------------------------------------------------------------------------------------------------------

                                                  * * * * * * *
R18-2-406..................  Permit             February 1, 2020..........  [INSERT Federal    Submitted on July
                              Requirements for                               Register           22, 2020.
                              Sources Located                                CITATION], June
                              in Attainment                                  16, 2021.
                              and
                              Unclassifiable
                              Areas.

                                                  * * * * * * *
----------------------------------------------------------------------------------------------------------------

* * * * *

0
4. In Sec.  52.145, revise paragraph (b) to read as follows:

Sec.  52.145   Visibility protection.

* * * * *
    (b) Regulations for visibility new source review. The provisions of
Sec.  52.28 are hereby incorporated and made part of the applicable
plan for the State of Arizona only for those stationary sources under
the permitting jurisdiction of the Pima County Department of
Environmental Quality or the Maricopa County Air Quality Department.
The provisions of Sec.  52.28 also remain the applicable plan for any
Indian reservation lands, and any other area of Indian country where
the EPA or an Indian tribe has demonstrated that a tribe has
jurisdiction, located within the State of Arizona.
* * * * *
[FR Doc. 2021-12431 Filed 6-15-21; 8:45 am]
BILLING CODE 6560-50-P