Finding of Failure To Attain for the Missouri Portion of the St. Louis Nonattainment Area for the 2015 Ozone National Ambient Air Quality Standards

ENVIRONMENTAL PROTECTION AGENCY <CFR>40 CFR Part 81</CFR> <DEPDOC>[EPA-R7-OAR-2025-0291; FRL-12824-01-R7]</DEPDOC> <SUBJECT>Finding of Failure To Attain for the Missouri Portion of the St. Louis Nonattainment Area for the 2015 Ozone National Ambient Air Quality 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 accepting comment on a determination that the Missouri portion of the St. Louis, MO-IL bi-state nonattainment area failed to attain the 2015 8-hour ozone National Ambient Air Quality Standards (NAAQS) by the applicable attainment date. The effect of failing to attain by the applicable attainment date is that the area is reclassified by operation of law to “Serious” nonattainment for the 2015 ozone NAAQS. On November 25, 2024, the EPA published a final action in the <E T="04">Federal Register</E> which determined that the St. Louis area failed to attain the 2015 ozone NAAQS by the Moderate area attainment date. That action also reclassified the area to Serious by operation of law with an effective date of December 31, 2024. On January 24, 2025, the EPA received a petition for reconsideration of that final action from the State of Missouri. On March 5, 2025, EPA Region 7 granted the petition for reconsideration and stated our intention to undergo a notice and comment rulemaking. Therefore, the EPA is accepting comment on the determination that the St. Louis area failed to attain by the attainment date. The Illinois portion of the St. Louis, MO-IL bi-state area is addressed separately. </SUM> <DATES> <HD SOURCE="HED">DATES:</HD> Comments must be received on or before July 21, 2025. </DATES> <HD SOURCE="HED">ADDRESSES:</HD> You may send comments, identified by Docket ID No. EPA-R07-OAR-2025-0291 to <E T="03">https://www.regulations.gov.</E> Follow the online instructions for submitting comments. <E T="03">Instructions:</E> All submissions received must include the Docket ID No. for this rulemaking. Comments received will be posted without change to <E T="03">https://www.regulations.gov,</E> including any personal information provided. For detailed instructions on sending comments and additional information on the rulemaking process, see the “Written Comments” heading of the <E T="02">SUPPLEMENTARY INFORMATION</E> section of this document. <FURINF> <HD SOURCE="HED">FOR FURTHER INFORMATION CONTACT:</HD> Ashley Keas, Environmental Protection Agency, Region 7 Office, Air and Radiation Division, 11201 Renner Boulevard, Lenexa, Kansas 66219; telephone number: (913) 551-7629; email address: <E T="03">keas.ashley@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. Written Comments</FP> <FP SOURCE="FP-2">II. Overview of Action</FP> <FP SOURCE="FP-2">III. What is the background for this action?</FP> <FP SOURCE="FP-2">IV. What is the statutory authority for this action?</FP> <FP SOURCE="FP-2">V. How does the EPA determine whether an area has attained the standard?</FP> <FP SOURCE="FP-2">VI. What is the EPA's determination for the area?</FP> <FP SOURCE="FP-2">VII. What action is the EPA proposing to take?</FP> <FP SOURCE="FP-2">VIII. Statutory and Executive Order Reviews</FP> </EXTRACT> <HD SOURCE="HD1">I. Written Comments</HD> Submit your comments, identified by Docket ID No. EPA-R07-OAR-2025-0291, at <E T="03">http://www.regulations.gov.</E> 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, the full EPA public comment policy, information about CBI or multimedia submissions, and general guidance on making effective comments, please visit <E T="03">http://www.epa.gov/dockets/commenting-epa-dockets.</E> <HD SOURCE="HD1">II. Overview of Action</HD> On November 25, 2024, the EPA published a final action in the <E T="04">Federal Register</E> which determined that the St. Louis area failed to attain the 2015 ozone NAAQS by the August 3, 2024, Moderate area attainment date. (See 89 FR 92816) That action also reclassified the area to Serious by operation of law with an effective date of December 31, 2024. On January 24, 2025, the EPA received a petition for reconsideration of that final action from the State of Missouri. On March 5, 2025, EPA Region 7 granted the petition for reconsideration and stated our intention to undergo a notice and comment rulemaking. Therefore, the EPA is publishing this proposed rule to accept comment on the determination that the St. Louis area failed to attain the 2015 ozone standard by the Moderate area attainment date. The EPA is required to determine whether areas designated nonattainment for an ozone NAAQS attained the standard by the applicable attainment date, and to take certain steps for areas that failed to attain (see CAA section 181(b)(2)). Per the explicit statutory language of CAA section 181(b)(2), the EPA's determination of attainment by the attainment date must be based on a nonattainment area's design value (DV) as of the attainment date. <SU>1</SU> <FTREF/> <FTNT> <SU>1</SU>  A DV is a statistic used to compare data collected at an ambient air quality monitoring site to the applicable NAAQS to determine compliance with the standard. The data handling conventions for calculating DVs for the 2015 ozone NAAQS are specified in appendix U to 40 CFR part 50. The DV for the 2015 ozone NAAQS is the 3-year average of the annual fourth highest daily maximum 8-hour average ozone concentration. The DV is calculated for each air quality monitor in an area, and the DV for an area is the highest DV among the individual monitoring sites located in the area. </FTNT> The 2015 ozone NAAQS is met at an EPA regulatory monitoring site when the DV does not exceed 0.070 parts per million (ppm). For Moderate nonattainment areas for the 2015 ozone NAAQS, the attainment date was August 3, 2024. Because the DV is based on the three most recent, complete calendar years of data, attainment must occur no later than December 31 of the year prior to the attainment date ( <E T="03">i.e.,</E> December 31, 2023, in the case of Moderate nonattainment areas for the 2015 ozone NAAQS). As such, the EPA's determinations for the Moderate nonattainment areas for the 2015 ozone NAAQS are based upon the complete, quality-assured, and certified ozone monitoring data from calendar years 2021, 2022, and 2023. This action addresses the Missouri portion of the St. Louis bi-state nonattainment area (hereafter St. Louis area) that was classified as Moderate for the 2015 ozone NAAQS as of the Moderate area attainment date of August 3, 2024. Table 1 provides a summary of the DVs and the EPA's air quality-based determinations for the St. Louis area. <GPOTABLE COLS="3" OPTS="L2,nj,i1" CDEF="s50,12,r100"> <TTITLE>Table 1—Summary of Nonattainment Areas in Missouri for the 2015 Ozone NAAQS</TTITLE> <CHED H="1">Nonattainment area</CHED> <CHED H="1">Attainment by the moderate area attainment date</CHED> <ROW> <ENT I="01">St. Louis</ENT> <ENT>0.074</ENT> <ENT>Failed to attain.</ENT> </ROW> </GPOTABLE> The EPA is accepting comment on the finding that the St. Louis area as shown in Table 1 did not attain by the attainment date, because the 2021-2023 DV is greater than 0.070 ppm. If the EPA determines that a nonattainment area classified as Moderate failed to attain by the attainment date, CAA section 181(b)(2)(B) requires the EPA to publish a notice in the <E T="04">Federal Register</E> , no later than 6 months following the attainment date, identifying each such area and identifying the applicable reclassification. The EPA's November 25, 2024, action fulfilled the EPA's obligation with respect to the St. Louis area. Under CAA section 181(b)(2)(A), areas that EPA finds have failed to attain by the attainment date are reclassified by operation of law to the next higher classification. The reclassification of the St. Louis Area to Serious became effective on December 31, 2024, and is still in effect. As such, the St. Louis area is currently subject to the Serious area requirement to attain the 2015 ozone NAAQS as expeditiously as practicable, but not later than August 3, 2027. Similarly, the other Serious area requirements remain in effect. Stationary air pollution sources in the St. Louis ozone nonattainment area became subject to Serious ozone nonattainment area New Source Review (NSR) and Title V permit requirements as a result of the area's reclassification. The source applicability thresholds for major sources and major source modification emissions are now 50 tons per year (tpy) for volatile organic compounds (VOC) and nitrogen oxides (NO <E T="52">X</E> ). For new and modified major stationary sources subject to review under Missouri regulation 10 CSR 10-6.060, in the EPA approved SIP, <SU>2</SU> <FTREF/> VOC and NO <E T="52">X</E> emission increases from the proposed construction of the new or modified major stationary sources must be offset by emission reductions by ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Preview showing 10k of 31k characters. Full document text is stored and available for version comparison. ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━