Proposed Rule2025-17498
Air Plan Revisions; Arizona; Maricopa County Air Quality Department; Volatile Organic Compounds; Solvent Cleaning
Primary source
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Published
September 11, 2025
Issuing agencies
Environmental Protection Agency
Abstract
The Environmental Protection Agency (EPA) is proposing to approve revisions to the Maricopa County Air Quality Department (MCAQD) portion of the Arizona State Implementation Plan (SIP). These revisions concern rules that regulate volatile organic compounds (VOC) emissions from solvent cleaning operations. We are proposing to approve the revisions under the Clean Air Act (CAA or "Act"). We are taking comments on this proposal and plan to follow with a final action.
Full Text
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<title>Federal Register, Volume 90 Issue 174 (Thursday, September 11, 2025)</title>
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[Federal Register Volume 90, Number 174 (Thursday, September 11, 2025)]
[Proposed Rules]
[Pages 43983-43986]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2025-17498]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 52
[EPA-R09-OAR-2025-0321; FRL-12854-01-R9]
Air Plan Revisions; Arizona; Maricopa County Air Quality
Department; Volatile Organic Compounds; Solvent Cleaning
AGENCY: Environmental Protection Agency (EPA).
ACTION: Proposed rule.
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SUMMARY: The Environmental Protection Agency (EPA) is proposing to
approve revisions to the Maricopa County Air Quality Department (MCAQD)
portion of the Arizona State Implementation Plan (SIP). These revisions
concern rules that regulate volatile organic compounds (VOC) emissions
from solvent cleaning operations. We are proposing to approve the
revisions under the Clean Air Act (CAA or ``Act''). We are taking
comments on this proposal and plan to follow with a final action.
DATES: Comments must be received on or before October 14, 2025.
ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R09-
OAR-2025-0321 at <a href="https://www.regulations.gov">https://www.regulations.gov</a>. For comments submitted at
<a href="http://Regulations.gov">Regulations.gov</a>, follow the online instructions for submitting
comments. Once submitted, comments cannot be edited or removed from
<a href="http://Regulations.gov">Regulations.gov</a>. The EPA may publish any comment received to its public
docket. Do not submit electronically any information you consider to be
Confidential Business Information (CBI) or other information whose
disclosure is restricted by statute. Multimedia submissions (audio,
video, etc.) must be accompanied by a written comment. The written
comment is considered the official comment and should include
discussion of all points you wish to make. The EPA will generally not
consider comments or comment contents located outside of the primary
submission (i.e., on the web, cloud, or other file sharing system). For
additional submission methods, please contact the person identified in
the FOR FURTHER INFORMATION CONTACT section. For the full EPA public
comment policy, information about CBI or multimedia
[[Page 43984]]
submissions, and general guidance on making effective comments, please
visit <a href="https://www.epa.gov/dockets/commenting-epa-dockets">https://www.epa.gov/dockets/commenting-epa-dockets</a>. If you need
assistance in a language other than English or if you are a person with
a disability 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: Allison Kawasaki, EPA Region IX, 75
Hawthorne St., San Francisco, CA 94105; telephone number: (415) 972-
3922; email address: <a href="/cdn-cgi/l/email-protection#0a616b7d6b796b6163246b6666637965644a6f7a6b246d657c"><span class="__cf_email__" data-cfemail="345f55435547555f5d1a5558585d475b5a745144551a535b42">[email protected]</span></a>.
SUPPLEMENTARY INFORMATION: Throughout this document, ``we,'' ``us,''
and ``our'' refer to the EPA.
Table of Contents
I. The State's Submittal
A. What did the State submit?
B. Are there other related submittals?
C. What is the purpose of the submittal?
II. The EPA's Evaluation and Action
A. How is the EPA evaluating the rule and the request for
rescission and replacement?
B. Do the SIP revisions meet the evaluation criteria?
C. Proposed Action and Public Comment
III. Incorporation by Reference
IV. Statutory and Executive Order Reviews
I. The State's Submittal
A. What did the State submit?
On October 3, 2024, the Arizona Department of Environmental Quality
(ADEQ) submitted a SIP revision to the EPA from MCAQD requesting that
the EPA approve MCAQD Rule 331--Solvent Cleaning (``Rule 331''), as
revised on September 25, 2024 (``2024 SIP Submittal''). Additionally,
the 2024 SIP Submittal requests that we rescind two sets of
requirements from the SIP: MCAQD Rule 331, as revised on April 21,
2004, and paragraphs F, G, H, I, J, and K of Rule 34--Organic
Solvents--Volatile Organic Compounds (VOC) (``Rule 34''), as revised on
June 23, 1980.
Table 1 lists the rule we are proposing for approval with the dates
that it was adopted by the local air agency and submitted to the EPA by
the ADEQ. Table 2 lists the rules proposed to be rescinded from the SIP
with the dates that they were adopted by the local air agency and
approved into the SIP.
Table 1--Submitted Rule for Approval
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Local agency Rule No. Rule title Revised Submitted
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MCAQD.................... 331 Solvent Cleaning.... September 25, 2024.. October 3, 2024.
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Table 2--Rules Requested To Be Rescinded or Replaced
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Local agency Rule No. Rule title Local revision date SIP approved date FR citation
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MCAQD.................... 34--paragraphs F, G, Organic Solvents-- June 23, 1980............... May 5, 1982................. 47 FR 19326.
H, I, J, and K. Volatile Organic
Compounds (VOC).
MCAQD.................... 331................. Solvent Cleaning... April 21, 2004.............. December 21, 2004........... 69 FR 76417.
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On April 3, 2025, the 2024 SIP Submittal was deemed by operation of
law to be complete. We have reviewed the submittal to ensure it meets
the completeness criteria in 40 CFR part 51, appendix V.
B. Are there other related submittals?
In 2016, the EPA reformatted the Arizona SIP as codified in the
Code of Federal Regulations (CFR) into a tabulated ``notebook'' format.
While developing the updated SIP tables for that conversion, the EPA
worked closely with ADEQ and the local air agencies to clarify what was
in their applicable SIP, including older provisions that had not been
updated or replaced to reflect local rulemakings. On September 13,
2017, because of that coordination, the ADEQ submitted a SIP revision
from MCAQD that requested to rescind or replace many obsolete rules in
their federally enforceable SIP in favor of rules that reflect their
current locally enforceable rulebook (``2017 SIP submittal'').
The 2017 SIP Submittal included requests related to Rule 34, MCAQD
Rule 330--Volatile Organic Compounds (``Rule 330''), and Rule 331. The
submittal requested that paragraphs F, G, H, I, J, and K of Rule 34 \1\
be replaced in the SIP by approval of Rule 330, as adopted on September
25, 2013. The submittal also requested that the EPA remove SIP-approved
Rule 331 \2\ and replace it in the SIP with Rule 331, as revised on
September 24, 2013. As clarified by MCAQD in the 2024 SIP Submittal,
these requests have been superseded by the 2024 SIP Submittal. Although
these requests have been superseded, this action is a part of this
ongoing effort.
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\1\ Approved into the SIP on May 5, 1982 (47 FR 19326).
\2\ Approved into the SIP on December 21, 2004 (69 FR 76417).
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If we finalize this rulemaking as proposed, Rule 331, as revised on
September 25, 2024, would replace Rule 34--paragraphs F, G, H, I, J,
and K and Rule 331, as revised on April 21, 2004, in the Maricopa
County portion of the Arizona SIP.
C. What is the purpose of the submittal?
Under title I of the CAA, the EPA has established ambient air
quality standards for six common air pollutants (``criteria
pollutants'') known to be harmful to human health and the environment:
carbon monoxide (CO), lead (Pb), nitrogen dioxide (NO<INF>2</INF>),
ozone, particulate matter (PM), and sulfur dioxide (SO<INF>2</INF>).
These standards are known as the National Ambient Air Quality Standards
(NAAQS).
Section 110(a) of the CAA requires states to submit SIP
requirements for the attainment and maintenance of the NAAQS. Rules 34
and Rule 331 regulate emissions of VOC from solvent cleaning
operations, including metal degreasing. Emissions of VOC contribute to
the production of ground-level ozone and PM. Cleaning solvents are used
to remove contaminants such as adhesives, inks, paint, dirt, soil, oil,
and grease from parts, products, tools, machinery, equipment, vessels,
floors, walls, and other work production related work areas. These
operations take place for a variety of reasons, including safety,
operability, and to avoid product contamination.
Additionally, MCAQD submitted revised Rule 331 to meet CAA
reasonably available control technology (RACT) requirements. CAA
sections 182(b)(2) and (f) require RACT for each category of sources
covered by a Control Techniques Guidelines (CTG) document
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as well as each major source of VOC or oxides of nitrogen
(NO<INF>X</INF>) in ozone nonattainment areas classified as
``Moderate'' or above. MCAQD regulates air quality in the Maricopa
County portion of the Phoenix-Mesa ozone nonattainment area, which is
classified as ``Moderate'' for the 2008 and 2015 8-hour ozone
standards.\3\ Rule 331 regulates categories of sources covered by CTG
documents related to solvents. For the 2008 8-hour ozone standard,
MCAQD relied on Rule 331, as revised on April 21, 2004, to meet RACT
requirements for certain CTG categories. MCAQD revised Rule 331 to meet
RACT requirements for the 2015 8-hour ozone standard. The EPA will
evaluate Rule 331 for RACT purposes when we review MCAQD's evaluation
in their RACT SIP for the 2015 8-hour ozone standard in a separate,
future action.
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\3\ 40 CFR 81.303; 87 FR 60897 (October 7, 2022); and 81 FR
26697 (May 4, 2016).
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MCAQD does not rely on Rule 34 to meet RACT requirements. MCAQD is
requesting the rescission of the remaining portions of Rule 34 \4\ in
the SIP as part of the ongoing effort to update the Maricopa County
portion of the Arizona SIP.
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\4\ On September 1, 2022 (87 FR 53676), in a direct final rule,
we clarified that paragraphs F, G, H, I, J and K of Rule 34 remain
in the Maricopa County portion of the SIP and that paragraphs A, B,
C, D, E, and L were rescinded or superseded by prior EPA actions.
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A technical support documents (TSD) was prepared for each rule,
Rule 34 and 331. The TSDs have more information about the rules.
II. The EPA's Evaluation and Action
A. How is the EPA evaluating the rule and the request for rescission
and replacement?
Emissions limitations in the SIP must be enforceable (see CAA
section 110(a)(2)) and must not interfere with applicable requirements
concerning attainment and reasonable further progress or other CAA
requirements (see CAA section 110(l)). Once a rule has been approved as
part of a SIP, the rescission of that rule from the SIP constitutes a
SIP revision. To approve such a revision, the change must comply with
restrictions on relaxation of SIP measures under CAA sections 110(l)
and 193. CAA section 193 requires control requirements in effect in
nonattainment areas prior to November 15, 1990, to remain in effect
unless the modification ensures equivalent or greater emissions
reductions.
Guidance and policy documents that we use to evaluate
enforceability and revision/relaxation requirements for the applicable
criteria pollutants include the following:
1.``Issues Relating to VOC Regulation Cutpoints, Deficiencies, and
Deviations,'' EPA, May 25, 1988 (the Bluebook, revised January 11,
1990).
2. ``Guidance Document for Correcting Common VOC & Other Rule
Deficiencies,'' EPA Region 9, August 21, 2001 (the Little Bluebook).
B. Do the SIP revisions meet the evaluation criteria?
Rule 331 establishes general work practices to minimize VOC
emissions for all solvent cleaning machines and for the handling of
cleaning solvents. For vapor and non-vapor cleaning machines,\5\
operators must meet additional solvent specifications, work practices,
control requirements, and/or design standards that limit VOC emissions
based on the type of cleaning machine utilized. Operators can also
choose to use an add-on emissions control system in lieu of the
requirements for cleaning machines if it meets an overall capture and
control efficiency of 85 percent. Additionally, using a ``Low VOC
Cleaner'' can justify exemption from many requirements in the rule,
especially for non-vapor cleaning machines.
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\5\ ``Vapor'' cleaning is when solvent vapor from boiling
cleaning solvent is used for cleaning and ``non-vapor'' cleaning is
when liquid solvent is used to clean at temperatures below the
solvent boiling point.
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Compared to the current SIP-approved version of Rule 331, the most
significant change was to revise the definition of ``Low VOC Cleaner''
from 50 grams per liter (g/L) to 25 g/L. This encourages operators to
switch to a lower emitting solvent to avoid the more substantive
requirements in the rule. Other revisions improve the overall clarity
and enforceability of the rule, such as providing clearer requirements
for emissions control systems, adding a compliance schedule section,
clarifying definitions, and clarifying monitoring, testing, and
recordkeeping requirements.
Rule 331, as revised on September 25, 2024, would strengthen the
SIP by establishing a more stringent emissions limitation for Low VOC
Cleaners and by clarifying monitoring and recordkeeping provisions.
This rule meets the relevant CAA requirements in section 110 and is
consistent with relevant guidance regarding enforceability and SIP
revisions.
Additionally, we are proposing that the requirements in Rule 331
can be used to replace Rule 34, paragraphs F, G, H, I, J, and K, in the
SIP. The requirements in Rule 34 would be replaced with requirements in
Rule 331 that are at least as stringent. For example, Rule 331 provides
updated terminology, more stringent standards (e.g., operational and
equipment standards, and work practices) and clarity on monitoring and
testing requirements.
Based on our evaluation, the replacement of Rule 34 with Rule 331,
as revised on September 25, 2024, would not impact the overall
stringency of the Arizona SIP and complies with CAA sections 110(l) and
193.
Our two TSDs have more information on our evaluations.
C. Proposed Action and Public Comment
As authorized in section 110(k)(3) of the Act, the EPA proposes to
approve Rule 331, as revised on September 25, 2024, because it fulfills
all relevant CAA requirements. It would replace the current version of
Rule 331 in the SIP. The EPA also proposes to approve the requested
rescission of Rule 34, sections F, G, H, I, J, and K, by replacing it
with Rule 331, as revised on September 25, 2024, because it fulfills
all relevant CAA requirements. We will accept comments from the public
on this proposal until October 14, 2025. If we take final action to
approve Rule 331, our final action will incorporate this rule into the
federally enforceable SIP.
III. Incorporation by Reference
In this document, the EPA is proposing to include in a final EPA
rule regulatory text that includes incorporation by reference. In
accordance with requirements of 1 CFR 51.5, the EPA is proposing to
incorporate by reference Maricopa County Air Quality District, Rule
331, Solvent Cleaning, revised September 25, 2024, which regulates
emissions of VOC from solvent cleaning operations. In addition, the EPA
is proposing to rescind Rule 34, sections F, G, H, I, J, and K, and
replace it with the submitted Rule 331 in the MCAQD portion of the
Arizona SIP, because the requested replacement fulfills all relevant
requirements. The EPA has made, and will continue to make, these
materials available through <a href="https://www.regulations.gov">https://www.regulations.gov</a> 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).
IV. Statutory and Executive Order Reviews
Under the CAA, the Administrator is required to approve a SIP
submission that complies with the provisions of the
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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 CAA.
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:
<bullet> Is not a significant regulatory action subject to review
by the Office of Management and Budget under Executive Order 12866 (58
FR 51735, October 4, 1993);
<bullet> Is not subject to Executive Order 14192 (90 FR 9065,
February 6, 2025) because SIP actions are exempt from review under
Executive Order 12866;
<bullet> Does not impose an information collection burden under the
provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
<bullet> Is certified as not having a significant economic impact
on a substantial number of small entities under the Regulatory
Flexibility Act (5 U.S.C. 601 et seq.);
<bullet> Does not contain any unfunded mandate or significantly or
uniquely affect small governments, as described in the Unfunded
Mandates Reform Act of 1995 (Pub. L. 104-4);
<bullet> Does not have federalism implications as specified in
Executive Order 13132 (64 FR 43255, August 10, 1999);
<bullet> Is not subject to Executive Order 13045 (62 FR 19885,
April 23, 1997) because it proposes to approve a state program;
<bullet> Is not a significant regulatory action subject to
Executive Order 13211 (66 FR 28355, May 22, 2001); and
<bullet> Is not subject to requirements of section 12(d) of the
National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272
note) because application of those requirements would be inconsistent
with the CAA.
In addition, the SIP is not approved to apply on any Indian
reservation land or in any other area where 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, Incorporation by
reference, Intergovernmental relations, Nitrogen oxides, Ozone,
Reporting and recordkeeping requirements, Volatile organic compounds.
Authority: 42 U.S.C. 7401 et seq.
Dated: September 3, 2025.
Michael Martucci,
Acting Regional Administrator, Region IX.
[FR Doc. 2025-17498 Filed 9-10-25; 8:45 am]
BILLING CODE 6560-50-P
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