Approval of Clean Air Plans; San Joaquin Valley, California; Contingency Measures for 1997 Ozone Standards

ENVIRONMENTAL PROTECTION AGENCY <CFR>40 CFR Part 52</CFR> <DEPDOC>[EPA-R09-OAR-2025-2466; FRL-13043-01-R9]</DEPDOC> <SUBJECT>Approval of Clean Air Plans; San Joaquin Valley, California; Contingency Measures for 1997 Ozone Standards</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 under the Clean Air Act (CAA or “Act”) a state implementation plan (SIP) submission from the State of California as meeting the attainment-related contingency measure requirements for the 1997 ozone national ambient air quality standards (NAAQS or “standards”) in the San Joaquin Valley, California, ozone nonattainment area. The SIP revision is titled “California Smog Check Contingency Measure State Implementation Plan Revision” (Released: September 15, 2023) (“Smog Check Contingency Measure SIP”). The EPA's proposed approval relies on the previously-approved contingency measure for the 1997 ozone NAAQS for the San Joaquin Valley and the justifications for not adopting additional contingency measures that provide for the recommended amount of emissions reductions for such measures. Based on the proposed approval, the EPA is also proposing to determine that the State of California has fulfilled the commitment made by the State in connection with a previous approval action to develop, adopt, and submit attainment contingency measures for the San Joaquin Valley for the 1997 ozone NAAQS meeting the requirements of the CAA. </SUM> <EFFDATE> <HD SOURCE="HED">DATES:</HD> Written comments must arrive on or before December 15, 2025. </EFFDATE> <HD SOURCE="HED">ADDRESSES:</HD> Submit your comments, identified by Docket ID No. EPA-R09-OAR-2025-2466 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. <FURINF> <HD SOURCE="HED">FOR FURTHER INFORMATION CONTACT:</HD> Laura Lawrence, EPA Region IX, (415) 972-3407, <E T="03">lawrence.laura@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. Background</FP> <FP SOURCE="FP1-2">A. Ozone Air Pollution and Regulatory Framework</FP> <FP SOURCE="FP1-2">B. The San Joaquin Valley Ozone Nonattainment Area</FP> <FP SOURCE="FP1-2">C. Previous EPA Actions Related to Contingency Measures for the 1997 Ozone NAAQS in San Joaquin Valley</FP> <FP SOURCE="FP-2">II. Contingency Measure Requirements and EPA Guidance</FP> <FP SOURCE="FP1-2">A. Statutory and Regulatory Requirements</FP> <FP SOURCE="FP1-2">B. Revised Contingency Measure Guidance</FP> <FP SOURCE="FP-2">III. Evaluation</FP> <FP SOURCE="FP1-2">A. Procedural Requirements for Adoption and Submission of SIP Revisions</FP> <FP SOURCE="FP1-2">B. Evaluation for Compliance With Clean Air Act Contingency Measure Requirements</FP> <FP SOURCE="FP-2">IV. Proposed Action</FP> <FP SOURCE="FP-2">V. Request for Public Comment</FP> <FP SOURCE="FP-2">VI. Statutory and Executive Order Reviews</FP> </EXTRACT> <HD SOURCE="HD1">I. Background</HD> <HD SOURCE="HD2">A. Ozone Air Pollution and Regulatory Framework</HD> Ground-level ozone pollution is formed from the reaction of volatile organic compounds (VOC) and oxides of nitrogen (NO <E T="52">X</E> ) in the presence of sunlight. <SU>1</SU> <FTREF/> These two pollutants, referred to as ozone precursors, are emitted by many types of sources, including on- and off-road motor vehicles and engines, power plants and industrial facilities, and smaller area sources such as lawn and garden equipment and paints. Scientific evidence indicates that adverse health effects occur following exposure to elevated levels of ozone, particularly in children and adults with lung disease. Breathing air containing ozone can reduce lung function and inflame airways, which can increase respiratory symptoms and aggravate asthma or other lung diseases. <SU>2</SU> <FTREF/> <FTNT> <SU>1</SU>  The State of California refers to reactive organic gases (ROG) rather than VOC in some of its ozone-related SIP submissions. As a practical matter, ROG and VOC refer to the same set of chemical constituents, and for the sake of simplicity, we refer to this set of gases as VOC in this proposed rulemaking. </FTNT> <FTNT> <SU>2</SU>  For more information on ozone health effects, see “Fact Sheet—2008 Final Revisions to the National Ambient Air Quality Standards for Ozone,” dated March 2008. </FTNT> Under section 109 of the Clean Air Act (CAA or “Act”), the EPA promulgates national ambient air quality standards (NAAQS or “standards”) for pervasive air pollutants, such as ozone. The NAAQS are concentration levels whose attainment and maintenance the EPA has determined to be requisite to protect public health and welfare. In 1979, under section 109 of the CAA, the EPA established primary and secondary standards for ozone at 0.12 parts per million (ppm) averaged over a 1-hour period. <SU>3</SU> <FTREF/> <FTNT> <SU>3</SU>  44 FR 8202 (February 8, 1979). </FTNT> In July 1997, the EPA revised the primary and secondary NAAQS for ozone to set the acceptable level of ozone in the ambient air at 0.08 ppm, averaged over an 8-hour period. <SU>4</SU> <FTREF/> The EPA set the 1997 8-hour ozone NAAQS based on scientific evidence demonstrating that ozone causes adverse health effects at lower concentrations and over longer periods of time than was understood when the pre-existing 1-hour ozone standards were set. The EPA determined that the 8-hour standard would be more protective of human health, especially for children and for adults who are active outdoors, and for individuals with a preexisting respiratory disease, such as asthma. <FTNT> <SU>4</SU>  62 FR 38856 (July 18, 1997). Primary standards provide public health protection, including protecting the health of “sensitive” populations such as people with asthma, children, and the elderly. Secondary standards provide public welfare protection, including protection against decreased visibility and damage to animals, crops, vegetation, and buildings. Since the primary and secondary standards established in 1997 are set at the same level, we refer to them herein using the singular “1997 ozone NAAQS” or “1997 ozone standard.” </FTNT> In March 2008, the EPA completed another review of the primary and secondary ozone standards and lowered the level for both to 0.075 ppm;  <SU>5</SU> <FTREF/> and in October 2015, the EPA further lowered the level of the standards to 0.070 ppm, <SU>6</SU> <FTREF/> but this action pertains only to the SIP requirements for the 1997 ozone standard. <FTNT> <SU>5</SU>  73 FR 16436 (March 27, 2008). </FTNT> <FTNT> <SU>6</SU>  80 FR 65292 (October 26, 2015). </FTNT> Following promulgation of a new or revised NAAQS, the EPA is required under CAA section 107(d) to designate areas throughout the country as attaining or not attaining the NAAQS. The EPA classifies ozone nonattainment areas under CAA section 181 according to the severity of the ozone pollution problem, with classifications ranging from “Marginal” to “Extreme.” State planning and emissions control requirements for ozone are determined, in part, by the nonattainment area's classification. In April 2004, the EPA designated the San Joaquin Valley as nonattainment for the 1997 ozone standard and classified the area as “Serious,” but, in May 2010, the EPA granted the State's voluntary reclassification of the area from “Serious” to “Extreme,” with an attainment date of no later than June 15, 2024. <SU>7</SU> <FTREF/> <FTNT> <SU>7</SU>  69 FR 23858 (April 30, 2004); 75 FR 24409 (May 5, 2010). </FTNT> Under the CAA, states with ozone nonattainment areas classified as “Serious” or above, such as the San Joaquin Valley area for the 1997 ozone NAAQS, must revise their SIPs to meet various requirements. Among the various SIP revision requirements, states must provide contingency measures to meet the requirements set forth in CAA sections 172(c)(9) and 182(c)(9). Contingency measures are additional controls or measures to be implemented in the event the area fails to make reasonable further progress (RFP), meet any applicable milestone, or attain the NAAQS by the attainment date. Additional information about the requirements for contingency measures ca ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Preview showing 10k of 105k characters. Full document text is stored and available for version comparison. ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━