Approval and Promulgation of Air Quality Implementation Plans; Nevada; Regional Haze State Implementation Plan for the Second Implementation Period

ENVIRONMENTAL PROTECTION AGENCY <CFR>40 CFR Part 52</CFR> <DEPDOC>[EPA-R09-OAR-2025-0101; FRL-12600-01-R9]</DEPDOC> <SUBJECT>Approval and Promulgation of Air Quality Implementation Plans; Nevada; 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> Proposed rule. <SUM> <HD SOURCE="HED">SUMMARY:</HD> The Environmental Protection Agency (EPA) is proposing to approve portions of the regional haze state implementation plan (SIP) revisions submitted by the Nevada Division of Environmental Protection (NDEP) on August 12, 2022 (“2022 Nevada Regional Haze Plan”) and on May 28, 2025 (“2025 SIP Supplement”), as satisfying applicable requirements under the Clean Air Act (CAA) and the EPA's Regional Haze Rule (RHR) for the program's second implementation period. These revisions address 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 revisions also address 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> <DATES> <HD SOURCE="HED">DATES:</HD> Written comments must be received on or before November 24, 2025. (1) <E T="03">Addresses:</E> Submit your comments, identified by Docket ID No. EPA-R09-OAR-2025-0101 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 a disability 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. </DATES> <FURINF> <HD SOURCE="HED">FOR FURTHER INFORMATION CONTACT:</HD> Emily Millar, Geographic Strategies & Modeling Section (ARD-2-2), Planning & Analysis Branch, Air & Radiation Division, EPA Region IX, 75 Hawthorne Street, San Francisco, CA 94105, telephone number: (213) 244-1882, email address: <E T="03">millar.emily@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. What action is the EPA proposing?</FP> <FP SOURCE="FP-2">II. Background and Requirements for Regional Haze Plans</FP> <FP SOURCE="FP1-2">A. Regional Haze Background</FP> <FP SOURCE="FP1-2">B. Roles of Agencies in Addressing Regional Haze</FP> <FP SOURCE="FP-2">III. Requirements for Regional Haze Plans for the Second Implementation Period</FP> <FP SOURCE="FP1-2">A. Long-Term Strategy for Regional Haze</FP> <FP SOURCE="FP1-2">B. Reasonable Progress Goals</FP> <FP SOURCE="FP1-2">C. Monitoring Strategy and Other State Implementation Plan Requirements</FP> <FP SOURCE="FP1-2">D. Requirements for Periodic Reports Describing Progress Towards the Reasonable Progress Goals</FP> <FP SOURCE="FP1-2">E. Requirements for State and Federal Land Manager Coordination</FP> <FP SOURCE="FP-2">IV. The EPA's Evaluation of Nevada's Regional Haze Submissions for the Second Implementation Period</FP> <FP SOURCE="FP1-2">A. Background on Nevada's First Implementation Period SIP Submission</FP> <FP SOURCE="FP1-2">B. Nevada's Second Implementation Period SIP Submissions and the EPA's Evaluation</FP> <FP SOURCE="FP1-2">C. Identification of Class I Areas</FP> <FP SOURCE="FP1-2">D. Calculations of Baseline, Current, and Natural Visibility Conditions; Progress to Date; and the Uniform Rate of Progress</FP> <FP SOURCE="FP1-2">E. Long-Term Strategy for Regional Haze</FP> <FP SOURCE="FP1-2">F. Reasonable Progress Goals</FP> <FP SOURCE="FP1-2">G. Additional Monitoring To Assess Reasonably Attributable Visibility Impairment</FP> <FP SOURCE="FP1-2">H. Monitoring Strategy and Other Implementation Plan Requirements</FP> <FP SOURCE="FP1-2">I. Requirements for Periodic Reports Describing Progress Towards the Reasonable Progress Goals</FP> <FP SOURCE="FP1-2">J. Requirements for State and Federal Land Manager Coordination</FP> <FP SOURCE="FP-2">V. Proposed Action</FP> <FP SOURCE="FP-2">VI. Incorporation by Reference</FP> <FP SOURCE="FP-2">VII. Statutory and Executive Order Reviews</FP> </EXTRACT> <HD SOURCE="HD1">I. What action is the EPA proposing?</HD> On August 12, 2022, NDEP submitted the 2022 Nevada Regional Haze Plan, titled “Nevada Regional Haze State Implementation Plan for the Second Planning Period” as a revision to the Nevada SIP to address regional haze for the second implementation period. <SU>1</SU> <FTREF/> NDEP made this SIP submission to satisfy the requirements of the CAA's regional haze program pursuant to CAA sections 169A and 169B and 40 CFR 51.308. The EPA found this submission complete on August 16, 2022. <SU>2</SU> <FTREF/> On July 27, 2023, NDEP withdrew the reasonable progress determinations for Tracy Generating Station's Piñon Pine Unit (also known variously as Tracy Unit 4 and Tracy Unit 7) and North Valmy Generating Station's Unit 1 and Unit 2. <SU>3</SU> <FTREF/> On May 28, 2025, NDEP submitted the 2025 SIP Supplement, titled “Nevada Regional Haze Revision to the State Implementation Plan for the Second Planning Period,” which includes revised reasonable progress determinations for those two sources. <SU>4</SU> <FTREF/> The 2025 Supplement also includes updated permits for three sources, replacing those submitted as part of the 2022 Nevada Regional Haze Plan. <SU>5</SU> <FTREF/> At this time the EPA is not proposing to act on the revised reasonable progress determinations for Tracy Unit 7 (Piñon Pine Unit 4) and North Valmy Generating Station's Unit 1 and Unit 2, which were included in the 2025 SIP Supplement. However, the EPA is proposing to find that the 2022 Nevada Regional Haze Plan, as revised by the July 27, 2023 partial withdrawal, and the permits submitted in appendix A of the 2025 SIP Supplement, meets the applicable statutory and regulatory requirements. Thus, we propose to approve the 2022 Nevada Regional Haze Plan (excluding the portions withdrawn on July 27, 2023) and appendix A (“Air Quality Permits Incorporated by Reference”) of the 2025 Supplement (collectively “the Plan”) into the Nevada SIP. <FTNT> <SU>1</SU>  Letter dated August 12, 2022, from Greg Lovato, Administrator, NDEP, to Martha Guzman, Regional Administrator, U.S. Environmental Protection Agency Region 9 (submitted electronically August 12, 2022). </FTNT> <FTNT> <SU>2</SU>  Letter dated August 16, 2022, from Elizabeth Adams, Director, Air and Radiation Division, EPA Region IX, to Greg Lovato, Administrator, NDEP. </FTNT> <FTNT> <SU>3</SU>  Letter dated July 27, 2023, from Jennifer L. Carr, Administrator, NDEP, to Martha Guzman, Regional Administrator, U.S. Environmental Protection Agency Region 9 (submitted electronically August 2, 2023). </FTNT> <FTNT> <SU>4</SU>  Letter dated May 23, 2025, from Jennifer L. Carr, Administrator, NDEP, to Josh F.W. Cook, Regional Administrator, U.S. Environmental Protection Agency Region 9 (submitted electronically May 27, 2025). </FTNT> <FTNT> <SU>5</SU>  2025 SIP Supplement, appendix A. </FTNT> <HD SOURCE="HD1">II. Background and Requirements for Regional Haze Plans</HD> A detailed history and background of the regional haze program is provided in multiple prior EPA proposal actions. <SU>6</SU> <FTREF/> For additional background on the 2017 RHR revisions, please refer to section III. Overview of Visibility Protection Statutory Authority, Regulation, and Implementation of “Protection of Visibility: Amendments to Requirements for State Plans” of the 2017 RHR. <SU>7</SU> <FTREF/> The following is an abbreviated history and background of the regional haze program and 2017 RHR as it applies to the current action. <FTNT> <SU>6</SU>  See 90 FR 13516 (March 24, 2025). </FTNT> <FTNT> <SU>7</SU>  See 82 FR 3078 (January 10, 2017), located at <E T="03">https://www.federalregister.gov/documents/2017/01/10/2017-00268/protection-of-visibility-amendments-to-requirements-for-State-plans#h-16</E> ). </FTNT> <HD SOURCE="HD2">A. Regional Haze Background</HD> In the 1977 CAA Amendments, Congress created a program for protecting visibility in the nation's mandatory Class I Federal areas, which include certain national parks and wilderness areas. <SU>8</SU> <FTREF/> The CAA establishes as a national goal the “prevention of any future, and the remedying of any existing, impairmen ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Preview showing 10k of 159k characters. Full document text is stored and available for version comparison. ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━