Approval of Air Quality Implementation Plans; California; Regional Haze State Implementation Plan for the Second Implementation Period

<RULE> ENVIRONMENTAL PROTECTION AGENCY <CFR>40 CFR Part 52</CFR> <DEPDOC>[EPA-R09-OAR-2025-0203; FRL-12755-02-R9]</DEPDOC> <SUBJECT>Approval of Air Quality Implementation Plans; California; Regional Haze State Implementation Plan for the Second Implementation Period</SUBJECT> <HD SOURCE="HED">AGENCY:</HD> Environmental Protection Agency (EPA). <HD SOURCE="HED">ACTION:</HD> Final rule. <SUM> <HD SOURCE="HED">SUMMARY:</HD> The Environmental Protection Agency (EPA) is approving the regional haze state implementation plan (SIP) revision submitted by California on August 9, 2022 (hereinafter the “2022 California Regional Haze Plan” or “the Plan”), under the Clean Air Act (CAA) and the EPA's Regional Haze Rule (RHR) for the program's second implementation period. The Plan addresses the requirement that states must periodically revise their long-term strategies for making reasonable progress towards the national goal of preventing any future, and remedying any existing, anthropogenic impairment of visibility, including regional haze, in mandatory Class I Federal areas. The Plan also addresses other applicable requirements for the second implementation period of the regional haze program. The EPA is taking this action pursuant to CAA sections 110 and 169A. </SUM> <EFFDATE> <HD SOURCE="HED">DATES:</HD> This final rule is effective on October 6, 2025. </EFFDATE> <HD SOURCE="HED">ADDRESSES:</HD> The EPA has established a docket for this action under Docket ID No. EPA-R09-OAR-2025-0203. All documents in the docket are listed on the <E T="03">www.regulations.gov</E> website. Although listed in the index, some information is not publicly available, <E T="03">e.g.,</E> confidential business information (CBI) or other information whose disclosure 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 <E T="03">www.regulations.gov,</E> or please contact the person identified in the <E T="02">For Further Information Contact</E> section for additional availability information. <FURINF> <HD SOURCE="HED">FOR FURTHER INFORMATION CONTACT:</HD> Emily Millar, Geographic Strategies and Modeling Section (ARD-2-2), Planning & Analysis Branch, EPA Region IX, by email at <E T="03">millar.emily@epa.gov</E> or phone at (213) 244-1882. </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. Background</FP> <FP SOURCE="FP-2">II. Rationale for Final Action</FP> <FP SOURCE="FP-2">III. Public Comments and EPA Responses</FP> <FP SOURCE="FP-2">IV. Final Action</FP> <FP SOURCE="FP-2">V. Statutory and Executive Order Reviews</FP> </EXTRACT> <HD SOURCE="HD1">I. Background</HD> On August 9, 2022, the California Air Resources Board (CARB) submitted the 2022 California Regional Haze Plan to address the requirements of the CAA's regional haze program pursuant to CAA sections 169A and 169B and 40 CFR 51.308. On December 19, 2024, the EPA proposed to approve the elements of the Plan related to requirements contained in 40 CFR 51.308(f)(1), 40 CFR 51.308(f)(4)-(6), and 40 CFR 51.308 (g)(1)-(5) and to disapprove the elements of the Plan related to requirements contained in 40 CFR 51.308(f)(2), 40 CFR 51.308(f)(3), and 40 CFR 51.308(i)(2)-(4). <SU>1</SU> <FTREF/> During that public notice-and-comment period, the EPA received six sets of comments. The full text of comments received on the December 19, 2024 proposal are available via Docket ID Number EPA-R09-OAR-2024-0459 at <E T="03">www.regulations.gov.</E> <FTNT> <SU>1</SU>  89 FR 103737. </FTNT> On June 18, 2025, the EPA withdrew the December 19, 2024 proposal and proposed full approval of the Plan. <SU>2</SU> <FTREF/> The June 18, 2025 proposal provided background on the requirements of the CAA and RHR, summarized California's regional haze SIP submittal, and explained the rationale for our proposed action. That background and rationale will not be restated in full here. <FTNT> <SU>2</SU>  90 FR 25929 (June 18, 2025). </FTNT> <HD SOURCE="HD1">II. Rationale for Final Action</HD> In this final action, the EPA is affirming the Agency's policy that, where projected 2028 visibility conditions on the most impaired days for a Class I Federal area impacted by a state are below the uniform rate of progress (URP) and the state has considered the four statutory factors, the state will have presumptively demonstrated reasonable progress for the second planning period for that area. The policy was first articulated in a proposed action on the West Virginia regional haze SIP for the second planning period, <SU>3</SU> <FTREF/> which was then finalized. <SU>4</SU> <FTREF/> <FTNT> <SU>3</SU>  90 FR 16478 (April 18, 2025). </FTNT> <FTNT> <SU>4</SU>  90 FR 29737, 29738 (July 7, 2025). </FTNT> All twenty-nine areas Class I areas in California and twenty-four out of the twenty-five Class I areas in neighboring states are below the adjusted URP, and the Plan demonstrated that the state took into consideration the four reasonable progress factors listed in CAA 169A(g)(1)  <SU>5</SU> <FTREF/> with respect to an adequate number of emissions sources. For the one remaining Class I area, Sycamore Canyon, projected 2028 visibility conditions on the most impaired days are above the adjusted URP. However, as detailed in our proposed rulemaking  <SU>6</SU> <FTREF/> and section IV.A.3 of the Response to Comments Document available in the docket for this action (“RTC Document”), there is uncertainty with respect to the trends in visibility impairment and whether the site will really be above the URP in 2028, due to the monitor location having been moved in 2015. In addition, there is a strong downward trend in observed sulfate and nitrates, and modeled source apportionment data from WRAP shows a strong downward trend in modeled U.S. anthropogenic contributions to Sycamore Canyon between the baseline and 2028. Furthermore, even if we assume that Sycamore Canyon will be above the URP in 2028, the available evidence indicates that this is due to local sources of coarse mass and fine soil, not pollution transported from outside of Arizona. Finally, while the EPA's policy establishes a presumption regarding areas that are projected to be <E T="03">below</E> the URP, states whose emissions contribute to impairment in areas <E T="03">above</E> the URP can still meet the applicable requirements of the CAA and the RHR. Indeed, the RHR specifically addresses this situation by requiring a “robust demonstration” that there are no additional emissions reduction measures at contributing sources that would be reasonable to include in the long-term strategy.”  <SU>7</SU> <FTREF/> Because California did not determine that its sources contribute to impairment in Sycamore Canyon, it did not expressly make such a demonstration. However, as described in section IV.A.3 of the RTC Document, even if Sycamore Canyon is assumed to be above the 2028 URP, we find, consistent with 40 CFR 51.308(f)(3)(ii)(B), that there are no additional emissions reduction measures for anthropogenic sources or groups of sources in California that may reasonably be anticipated to contribute to visibility impairment in the Sycamore Canyon that would be reasonable to include in California's own long-term strategy. Thus, the EPA has determined that the Plan is fully approvable under the CAA, the RHR and the Agency's new policy. <FTNT> <SU>5</SU>  The four statutory factors required to be taken into consideration in determining reasonable progress are: the costs of compliance, the time necessary for compliance, and the energy and nonair quality environmental impacts of compliance, and the remaining useful life of any existing source subject to such requirements. CAA section 169(g)(1). </FTNT> <FTNT> <SU>6</SU>  90 FR 25929, 25940. </FTNT> <FTNT> <SU>7</SU>  40 CFR 51.308(f)(3)(ii)(B). </FTNT> <HD SOURCE="HD1">III. Public Comments and EPA Responses</HD> The EPA's June 18, 2025 proposal provided a 30-day public comment period that ended on July 18, 2025. The EPA received 10 comments during the comment period: one anonymous comment; four comments from private individuals; a comment letter from the California Air Resources Board (CARB); a comment from Mid-Atlantic/Northeast Visibility Union (MANEVU); a comment from the Power Generators Air Coalition; a joint comment letter signed by Access Fund, Central California Asthma Collaborative, Central California Environmental Justice Network, Central Valley Air Quality Coalition, Clean Water Action, Coalition to Protect America's National Parks, and the National Parks Conservation Association (NPCA); and a joint comment letter signed by NPCA, Sierra Club, and Coalition to Protect America's National Parks. After reviewing the anonymous comment and the comments from the private individuals, the EPA has determined that they fail to raise issues germane to the approval of the Plan, which is based on the criteria set forth in the Act, the RHR and relevant policy documents. Therefore, we have determined that these comments do not necessitate a response, and the EPA will not provide specific response to these comments. The comments from CARB and the Power Generators Air Coalition supported the EPA's proposed action. The EPA acknowledges these supportive comments, which are included in the docket for this action. We respond to the issues raised in the three remaining comment letters received on our proposed rulemaking in this document and the associated RTC Document, which is included in the docket for this rulemaking. We briefly address in this section: (1) ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Preview showing 10k of 29k characters. Full document text is stored and available for version comparison. ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━