Air Plan Revisions; California; Mojave Desert Air Quality Management District; New Source Review; Stationary Source Permits

ENVIRONMENTAL PROTECTION AGENCY <CFR>40 CFR Part 52</CFR> <DEPDOC>[EPA-R09-OAR-2025-0625; FRL-12877-02-R9]</DEPDOC> <SUBJECT>Air Plan Revisions; California; Mojave Desert Air Quality Management District; New Source Review; Stationary Source Permits</SUBJECT> <HD SOURCE="HED">AGENCY:</HD> Environmental Protection Agency (EPA). <HD SOURCE="HED">ACTION:</HD> Proposed rule. <SUM> <HD SOURCE="HED">SUMMARY:</HD> The Environmental Protection Agency (EPA) is proposing conditional approval of five permitting rules as a revision to the Mojave Desert Air Quality Management District (MDAQMD) portion of the California State Implementation Plan (SIP). These are revisions to the District's New Source Review (NSR) air permitting program rules for new and modified sources of air pollution under the Clean Air Act (CAA or “Act”). The submitted rules address deficiencies identified in a previous limited disapproval action and incorporate other revisions related to the NSR permitting requirements. If finalized, this action will update the MDAQMD's current SIP with the revised rules. As a separate action in this <E T="04">Federal Register</E> , we are making an interim final determination that will stay or defer the imposition of CAA sanctions associated with our previous limited disapproval action. </SUM> <EFFDATE> <HD SOURCE="HED">DATES:</HD> Comments must be received on or before August 25, 2025. </EFFDATE> <HD SOURCE="HED">ADDRESSES:</HD> Submit your comments, identified by Docket ID No. EPA-R09-OAR-2025-0625 at <E T="03">https://www.regulations.gov.</E> For comments submitted at <E T="03">Regulations.gov</E> , follow the online instructions for submitting comments. Once submitted, comments cannot be edited or removed from <E T="03">Regulations.gov</E> . 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 ( <E T="03">i.e.,</E> on the web, cloud, or other file sharing system). For additional submission methods, please contact the person identified in the <E T="02">FOR FURTHER INFORMATION CONTACT</E> section. For the full EPA public comment policy, information about CBI or multimedia submissions, and general guidance on making effective comments, please visit <E T="03">https://www.epa.gov/dockets/commenting-epa-dockets.</E> 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 <E T="02">FOR FURTHER INFORMATION CONTACT</E> section. <FURINF> <HD SOURCE="HED">FOR FURTHER INFORMATION CONTACT:</HD> Shaheerah Kelly, U.S. Environmental Protection Agency, Region IX (AIR-3-2), telephone number: (415) 947-4156, email address: <E T="03">kelly.shaheerah@epa.gov.</E> </FURINF> <SUPLINF> <HD SOURCE="HED">SUPPLEMENTARY INFORMATION:</HD> Throughout this document, “we,” “us,” and “our” refer to the EPA. <HD SOURCE="HD1">Table of Contents</HD> <EXTRACT> <FP SOURCE="FP-2">I. The State's Submittal</FP> <FP SOURCE="FP1-2">A. What rules are in the current SIP?</FP> <FP SOURCE="FP1-2">B. What rules did the State submit?</FP> <FP SOURCE="FP1-2">C. What is the purpose of the submitted rule revisions?</FP> <FP SOURCE="FP-2">II. The EPA's Evaluation and Action</FP> <FP SOURCE="FP1-2">A. What is the background for this proposal?</FP> <FP SOURCE="FP1-2">B. How is the EPA evaluating the rules?</FP> <FP SOURCE="FP1-2">C. Do the rules meet the evaluation criteria?</FP> <FP SOURCE="FP1-2">D. How do the rule revisions address the deficiencies?</FP> <FP SOURCE="FP1-2">E. Proposed Action and Public Comment</FP> <FP SOURCE="FP-2">III. Incorporation by Reference</FP> <FP SOURCE="FP-2">IV. Statutory and Executive Order Reviews</FP> </EXTRACT> <HD SOURCE="HD1">Definitions</HD> <EXTRACT> For the purpose of this document, we are giving meaning to certain words or initials as follows: (i) The word or initials <E T="03">MDAQMD</E> or <E T="03">District</E> mean or refer to the Mojave Desert Air Quality Management District. (ii) The word or initials <E T="03">CAA</E> or <E T="03">Act</E> mean or refer to the Clean Air Act, unless the context indicates otherwise. (iii) The word or initials <E T="03">CARB</E> mean or refer to the California Air Resources Board. (iv) The initials <E T="03">CFR</E> mean or refer to Code of Federal Regulations. (v) The initials or words <E T="03">EPA, we, us,</E> or <E T="03">our</E> mean or refer to the United States Environmental Protection Agency. (vi) The initials <E T="03">NA</E> mean or refer to nonattainment. (vii) The initials <E T="03">NAAQS</E> mean or refer to the National Ambient Air Quality Standards. (viii) The initials <E T="03">NSR</E> mean or refer to New Source Review. (ix) The initials <E T="03">NNSR</E> mean or refer to nonattainment New Source Review. (x) The initials <E T="03">SIP</E> mean or refer to State Implementation Plan. (xi) The word <E T="03">State</E> means or refers to the State of California. (xii) The word <E T="03">TSD</E> means or refers to the Technical Support Document. </EXTRACT> <HD SOURCE="HD1">I. The State's Submittal</HD> <HD SOURCE="HD2">A. What rules are in the current SIP?</HD> Table 1 lists the rules in the current SIP with the dates they were previously amended or revised by MDAQMD, submitted by the California Air Resources Board (CARB), the governor's designee for California SIP submittals, and approved by the EPA. <GPOTABLE COLS="5" OPTS="L2,nj,i1" CDEF="s50,r75,15,12,16"> <TTITLE>Table 1—Current SIP Rules</TTITLE> <CHED H="1">Rule No.</CHED> <CHED H="1">Rule title</CHED> <CHED H="1"> State effective <ENT>New Source Review Requirements</ENT> <ENT>3/22/2021</ENT> <ENT>6/30/2023</ENT> <ENT>88 FR 42258</ENT> </ROW> <ROW> <ENT I="01">1304</ENT> <ENT>New Source Review Emissions Calculations</ENT> <ENT>3/22/2021</ENT> <ENT>6/30/2023</ENT> <ENT>88 FR 42258</ENT> </ROW> <ROW> <ENT I="01">1305</ENT> <ENT>New Source Review Emission Offsets</ENT> <ENT>3/22/2021</ENT> <ENT>6/30/2023</ENT> <ENT>88 FR 42258</ENT> </ROW> </GPOTABLE> <HD SOURCE="HD2">B. What rules did the State submit?</HD> Table 2 lists the rules addressed by this proposal with the dates they were amended or revised by the MDAQMD and submitted by CARB, the agency that serves as the governor's designee for California SIP submittals. <GPOTABLE COLS="4" OPTS="L2,i1" CDEF="s50,r75,12,12"> <TTITLE>Table 2—Submitted Rules</TTITLE> <CHED H="1">Rule No.</CHED> <CHED H="1">Rule title</CHED> <ENT>New Source Review Requirements</ENT> <ENT>3/25/2024</ENT> <ENT>8/7/2024</ENT> </ROW> <ROW> <ENT I="01">1304</ENT> <ENT>New Source Review Emissions Calculations</ENT> <ENT>3/25/2024</ENT> <ENT>8/7/2024</ENT> </ROW> <ROW> <ENT I="01">1305</ENT> <ENT>New Source Review Emission Offsets</ENT> <ENT>3/25/2024</ENT> <ENT>8/7/2024</ENT> </ROW> </GPOTABLE> On February 7, 2025, CARB's August 7, 2024 submittal (hereafter referred to as the “2024 Submittal”) for the MDAQMD was deemed complete by operation of law according to 40 CFR part 51, appendix V, which must be met before formal EPA review. <FTREF/> <FTNT> <SU>1</SU>  Subsections 1302(C)(5)(d) and 1302(C)(7)(c)(iii) of Rule 1302 specifically state that subsections 1302(C)(5) and 1302(C)(7)(c) are not submitted to the EPA and are not intended to be included as part of the California SIP. </FTNT> <HD SOURCE="HD2">C. What is the purpose of the submitted rule revisions?</HD> The 2024 Submittal is intended to address certain deficiencies identified by the EPA in the MDAQMD Rules 1301, 1302, 1303, 1304, and 1305 listed in table 1. The deficiencies pertain to certain applicable nonattainment NSR requirements under the CAA, in part D of title I of the Act, and the implementing regulations under 40 CFR 51.165. The nonattainment areas under the MDAQMD's jurisdiction are the San Bernardino County portion of the West Mojave Desert nonattainment area which is designated as a Severe nonattainment area for the 2008 and 2015 8-hour ozone NAAQS, and the Trona Planning Area in San Bernardino County which is designated as a Moderate nonattainment area for the 1987 PM <E T="52">10</E> NAAQS. 40 CFR 81.305. The rules listed in table 2 are intended to replace the rules currently in the SIP as listed in table 1. <HD SOURCE="HD1">II. The EPA's Evaluation and Action</HD> <HD SOURCE="HD2">A. What is the background for this proposal?</HD> On November 25, 2022, the EPA proposed a limited approval/limited disapproval action for MDAQMD's Regulation XIII NSR Rules. <SU>2</SU> <FTREF/> On June 30, 2023, the EPA finalized this limited approval/limited disapproval action (hereafter called the “2023 NSR Action”). <SU>3</SU> <FTREF/> As authorized in sections 110(k)(3) and 301(a) of the Act, the EPA finalized a limited approval and limited disapproval of Rules 1301, 1302, 1303, 1304, and 1305 because although they fulfill most of the relevant CAA requirements and strengthen the SIP, they also contained six deficiencies that did not fully satisfy the relevant requirements for preconstruction review and permitting under section 110 and part D of title I of the Act. The deficiencies are described in the October 5, 2022 TSD for the action, as well as in the preambles to the November 25, 2022 proposed rule and the 2023 NSR Action. 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