90 FR 117 pgs. 26240-26244 - Finding of Failure To Attain for the Missouri Portion of the St. Louis Nonattainment Area for the 2015 Ozone National Ambient Air Quality Standards
Type: PRORULEVolume: 90Number: 117Pages: 26240 - 26244
Pages: 26240, 26241, 26242, 26243, 26244Docket number: [EPA-R7-OAR-2025-0291; FRL-12824-01-R7]
FR document: [FR Doc. 2025-11304 Filed 6-18-25; 8:45 am]
Agency: Environmental Protection Agency
Official PDF Version: PDF Version
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 81
[EPA-R7-OAR-2025-0291; FRL-12824-01-R7]
Finding of Failure To Attain for the Missouri Portion of the St. Louis Nonattainment Area for the 2015 Ozone National Ambient Air Quality Standards
AGENCY:
Environmental Protection Agency (EPA).
ACTION:
Proposed rule.
SUMMARY:
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 Federal Register 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.
DATES:
Comments must be received on or before July 21, 2025.
ADDRESSES:
You may send comments, identified by Docket ID No. EPA-R07-OAR-2025-0291 to https://www.regulations.gov. Follow the online instructions for submitting comments.
Instructions: All submissions received must include the Docket ID No. for this rulemaking. Comments received will be posted without change to https://www.regulations.gov, 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 SUPPLEMENTARY INFORMATION section of this document.
FOR FURTHER INFORMATION CONTACT:
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: keas.ashley@epa.gov.
SUPPLEMENTARY INFORMATION:
Throughout this document "we," "us," and "our" refer to the EPA.
Table of Contents
I. Written Comments
II. Overview of Action
III. What is the background for this action?
IV. What is the statutory authority for this action?
V. How does the EPA determine whether an area has attained the standard?
VI. What is the EPA's determination for the area?
VII. What action is the EPA proposing to take?
VIII. Statutory and Executive Order Reviews
I. Written Comments
Submit your comments, identified by Docket ID No. EPA-R07-OAR-2025-0291, at http://www.regulations.gov. Once submitted, comments cannot be edited or removed from Regulations.gov . 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 i.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 http://www.epa.gov/dockets/commenting-epa-dockets.
II. Overview of Action
On November 25, 2024, the EPA published a final action in the Federal Register 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. 1
Footnotes:
1 ?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.
[top] 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
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.
| Nonattainment area | 2021-2023 Design value (DV) (ppm) | Attainment by the moderate area attainment date |
|---|---|---|
| St. Louis | 0.074 | Failed to attain. |
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 Federal Register , 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 X ). For new and modified major stationary sources subject to review under Missouri regulation 10 CSR 10-6.060, in the EPA approved SIP, 2 VOC and NO X emission increases from the proposed construction of the new or modified major stationary sources must be offset by emission reductions by a minimum offset ratio of 1.20 to 1 (see CAA section 182(c)(10)). These permitting requirements associated with the Serious classification remain in effect.
Footnotes:
2 ?Specifically, we are referring to the EPA-approved Missouri regulation 10 Code of State Regulations (CSR) 10-6.060, titled "Construction Permits Required." Most recently revised and approved into Missouri's SIP on August 11, 2022. (85 FR 49530)
Additionally, Missouri must submit to the EPA the SIP revisions for this area that satisfy the statutory and regulatory requirements applicable to Serious areas established in CAA section 182(c), the 2015 Ozone NAAQS SIP Requirements Rule (see 83 FR 62998, December 6, 2018) and the Ozone Reclassifications Requirements Rule (see 90 FR 5651, January 17, 2025), which also established SIP submission and control measure implementation deadlines for newly reclassified areas (see 40 CFR 51.1402).
III. What is the background for this action?
On October 26, 2015, the EPA issued its final action to revise the NAAQS for ozone to establish a new 8-hour standard ( see 80 FR 65452, October 26, 2015). In that action, the EPA promulgated identical tighter primary and secondary ozone standards designed to protect public health and welfare that specified an 8-hour ozone level of 0.070 ppm. Specifically, the standards require that the 3-year average of the annual fourth highest daily maximum 8-hour average ozone concentration may not exceed 0.070 ppm.
Effective on August 3, 2018, the EPA designated 52 areas throughout the country as nonattainment for the 2015 ozone NAAQS ( see 83 FR 25776, June 4, 2018). As part of that action, the EPA designated the St. Louis, MO-IL bi-state area as Marginal nonattainment for the 2015 Ozone NAAQS. The area included Boles Township of Franklin County, St. Charles County, St. Louis County, and St. Louis City in Missouri, and Madison and St. Clair Counties in Illinois. As part of that same action, EPA designated Jefferson County and the remaining portion of Franklin County, in Missouri, and Monroe County in Illinois, as attainment/unclassifiable. On July 10, 2020, the U.S. Court of Appeals for the District of Columbia remanded the Jefferson County, Missouri, and Monroe County, Illinois, designations (among other designations) to the EPA. The Court upheld EPA's designation of Boles Township as nonattainment and the remainder of Franklin County as attainment/unclassifiable. In response to the Court's remand, the EPA revised the Jefferson County, Missouri, and Monroe County, Illinois designation to nonattainment on May 26, 2021 (86 FR 31438).
[top] In a separate action, the EPA classified and established attainment dates for each classification in accordance with CAA section 181(a)(1), based on the severity of an area's ozone problem, determined by the area's DV (see 83 FR 10376, May 8, 2018). The EPA established the maximum attainment date for Marginal, Moderate, and Serious nonattainment areas as 3 years, 6 years, and 9 years, respectively, from the effective date of the final designations. Thus, the attainment date for any nonattainment areas classified as Marginal for the 2015 ozone NAAQS was August 3, 2021, the attainment date for Moderate areas was August 3, 2024, and the attainment date for Serious areas is August 3, 2027. On October 7, 2022 (87 FR 60897), the EPA determined that 22 areas, including the St. Louis area addressed in this action, did not attain the standards by the Marginal attainment date, and were reclassified as Moderate by operation of law.
IV. What is the statutory authority for this action?
The statutory authority for this determination is provided by the CAA, as amended (42 U.S.C. 7401 et seq. ). Relevant portions of the CAA include, but are not necessarily limited to, sections 181 and 182.
CAA section 107(d) provides that when the EPA establishes or revises a NAAQS, the agency must designate areas of the country as nonattainment, attainment, or unclassifiable based on whether an area is not meeting (or is contributing to air quality in a nearby area that is not meeting) the NAAQS, meeting the NAAQS, or cannot be classified as meeting or not meeting the NAAQS, respectively. Subpart 2 of part D of title I of the CAA governs the classification, state planning, and emissions control requirements for any areas designated as nonattainment for a revised primary ozone NAAQS. In particular, CAA section 181(a)(1) requires each area designated as nonattainment for a revised ozone NAAQS to be classified at the same time as the area is designated based on the extent of the ozone problem in the area (as determined based on the area's DV). Classifications for ozone nonattainment areas are "Marginal," "Moderate," "Serious," "Severe," and "Extreme," in order of stringency. CAA section 181(a)(1) also establishes attainment dates for each area classified under that section. CAA section 182 provides the specific attainment planning and additional requirements that apply to each ozone nonattainment area based on its classification.
Section 181(b)(2)(A) of the CAA requires that within 6 months following the applicable attainment date, the EPA shall determine whether an ozone nonattainment area attained the ozone standard based on the area's DV as of that date. Under CAA section 181(a)(5) as interpreted by the EPA in 40 CFR 51.1307, upon application by any state, the EPA may grant a 1-year extension to the attainment date when certain criteria are met. One criterion for a first attainment date extension is that an area's fourth highest daily maximum 8-hour value for the attainment year must not exceed the level of the standard. In the event an area fails to attain the ozone NAAQS by the applicable attainment date and is not granted a 1-year attainment date extension, CAA section 181(b)(2)(A) requires the EPA to make the determination that an ozone nonattainment area failed to attain the ozone standard by the applicable attainment date, and requires the area to be reclassified by operation of law to the higher of: (1) The next higher classification for the area, or (2) the classification applicable to the area's DV as of the determination of failure to attain. 3 Section 181(b)(2)(B) of the CAA requires the EPA to publish the determination of failure to attain and accompanying reclassification in the Federal Register no later than 6 months after the attainment date, which in the case of the St. Louis area was February 3, 2025. The EPA's November 25, 2024, action fulfilled the EPA's obligation with respect to the St. Louis area.
Footnotes:
3 ?The nonattainment area named in this action that failed to attain by the attainment date would be classified to the next higher classification, Serious. The affected area's DV as of the attainment date does not otherwise place the area in a higher classification.
Once an area is reclassified, each state that contains a reclassified area is required to submit certain SIP revisions in accordance with its more stringent classification. The SIP revisions are intended to, among other things, demonstrate how the area will attain the NAAQS as expeditiously as practicable, but no later than August 3, 2027, the Serious area attainment date for the 2015 ozone NAAQS. Per CAA section 182(i), a state with a reclassified ozone nonattainment area must submit the applicable attainment plan requirements "according to the schedules prescribed in connection with such requirements" in CAA section 182(c) for Serious areas, but the EPA "may adjust applicable deadlines (other than attainment dates) to the extent such adjustment is necessary or appropriate to assure consistency among the required submissions." The EPA addressed the SIP revision and implementation deadlines for newly reclassified Serious areas, as well as the continued applicability of Moderate area requirements, if they have not yet been met, in a separate rulemaking. (See 90 FR 5651, January 17, 2025)
V. How does the EPA determine whether an area has attained the standard?
The level of the 2015 ozone NAAQS is 0.070 ppm. 4 Under the EPA regulations at 40 CFR part 50, appendix U, the 2015 ozone NAAQS is attained at a site when the 3-year average of the annual fourth highest daily maximum 8-hour average ambient ozone concentration ( i.e., DV) does not exceed 0.070 ppm. When the DV does not exceed 0.070 ppm at each ambient air quality monitoring site within the area, the area is deemed to be attaining the ozone NAAQS. Each area's DV is determined by the highest DV among monitors with valid DVs. 5 The data handling convention in appendix P dictates that concentrations shall be reported in "ppm" to the third decimal place, with additional digits to the right being truncated. Thus, a computed 3-year average ozone concentration of 0.071 ppm is greater than 0.070 ppm and would exceed the standard, but a computed 3-year average ozone concentration of 0.0709 ppm is truncated to 0.070 ppm and attains the 2015 ozone NAAQS.
Footnotes:
4 ?See 40 CFR 50.19.
5 ?According to appendix U to 40 CFR part 50, ambient monitoring sites with a DV of 0.070 ppm or less must meet minimum data completeness requirements in order to be considered valid. These requirements are met for a 3-year period at a site if daily maximum 8-hour average ozone concentrations are available for at least 90% of the days within the ozone monitoring season, on average, for the 3-year period, with a minimum of at least 75% of the days within the ozone monitoring season in any one year. Ozone monitoring seasons are defined for each State in appendix D to 40 CFR part 58. DVs greater than 0.070 ppm are considered to be valid regardless of the data completeness.
The EPA's proposed determination of attainment is based upon the area's design value as of August 3, 2024, which in turn is calculated using hourly ozone concentration data for calendar years 2021, 2022 and 2023 that have been collected and quality-assured in accordance with 40 CFR part 58 and reported to the EPA's Air Quality System (AQS) database. 6
Footnotes:
6 ?The EPA maintains the AQS, a database that contains ambient air pollution data collected by the EPA, state, local, and tribal air pollution control agencies. The AQS also contains meteorological data, descriptive information about each monitoring station (including its geographic location and its operator) and data quality assurance/quality control information. The AQS data is used to (1) assess air quality, (2) assist in attainment/non-attainment designations, (3) evaluate SIPs for non-attainment areas, (4) perform modeling for permit review analysis, and (5) prepare reports for Congress as mandated by the CAA. Access is through the website at https://www.epa.gov/aqs.
[top] State and local monitoring network plans are subject to approval by the EPA on an annual basis and any interim modifications to those plans must also be approved by the EPA. 7 The annual monitoring network plan process is provided in 40 CFR 58.10 and the requirements governing system modifications and monitor discontinuations are laid out in 40 CFR 58.14. Where state or local agencies seek to modify the ambient air quality monitoring networks by discontinuing a monitor station, the EPA may approve such modifications subject to the criteria established in 40 CFR 58.14(c). The EPA may not approve such discontinuation if doing so would
Footnotes:
7 ?Annual monitoring network plans for each state are available at https://www.epa.gov/amtic/state-monitoring-agency-annual-air-monitoring-plans-and-network-assessments.
VI. What is the EPA's determination for the area?
The EPA is accepting comment on the finding that the St. Louis nonattainment area addressed in this action failed to attain the 2015 ozone NAAQS by the attainment date of August 3, 2024. As shown in Table 1, at least one monitor in this area had a 2021-2023 DV greater than 0.070 ppm. 8 Table 2 shows the annual fourth highest daily maximum 8-hour average ozone concentration and 2021-2023 DV for each monitor in the St. Louis, MO-IL area.
Footnotes:
8 ?See definition of design value in 40 CFR 58.1, "means the calculated concentration according to the applicable appendix of part 50 of this chapter for the highest site in an attainment or nonattainment area." See also appendix U to 40 CFR part 50.
| AQS site ID | County | State | Fourth highest daily maximum 8-hour average ozone concentration (ppm) | 2021 | 2022 | 2023 | 2021-2023 design value (DV) (ppm) |
|---|---|---|---|---|---|---|---|
| 290990019 | Jefferson | Missouri | 0.073 | 0.067 | 0.078 | 0.072 | |
| 291831002 | Saint Charles | Missouri | 0.067 | 0.071 | 0.080 | 0.072 | |
| 291831004 | Saint Charles | Missouri | 0.065 | 0.067 | 0.073 | 0.068 | |
| 291890005 | Saint Louis | Missouri | 0.065 | 0.061 | 0.077 | 0.067 | |
| 291890014 | Saint Louis | Missouri | 0.065 | 0.067 | 0.081 | 0.071 | |
| 295100085 | St. Louis City | Missouri | 0.068 | 0.068 | 0.077 | 0.071 | |
| 171190120 | Madison | Illinois | 0.070 | 0.076 | 0.078 | 0.074 | |
| 171190122 | Madison | Illinois | 0.070 | 0.067 | 0.078 | 0.071 | |
| 171193007 | Madison | Illinois | 0.070 | 0.072 | 0.077 | 0.073 | |
| 171630010 | Saint Clair | Illinois | 0.066 | 0.067 | 0.077 | 0.070 | |
| *?Monitors that did not meet completeness criteria and do not have a valid design value are not shown. | |||||||
VII. What action is the EPA proposing to take?
Effective December 31, 2024, the EPA determined that the Missouri portion of the St. Louis area failed to attain by the Moderate 2015 ozone attainment date, and the area was therefore reclassified by operation of law to Serious for the 2015 ozone NAAQS. Missouri submitted a petition for reconsideration to the Agency on January 24, 2025, asserting that the state did not have an opportunity to comment on the Agency's determination. The EPA granted the state's request for reconsideration on March 5, 2025, and is in this proposed notice accepting comment on the Agency's determination that the area failed to attain by the Moderate 2015 ozone attainment date based on the area's design value as of the attainment date.
VIII. Statutory and Executive Order Reviews
A. Executive Order 12866: Regulatory Planning and Review
This action is not a "significant regulatory action" under the terms of Executive Order 12866 (58 FR 51735, October 4, 1993).
B. Executive Order 14192: Unleashing Prosperity Through Deregulation
This action is not subject to Executive Order 14192 (90 FR 9065, February 6, 2025) because Section 181 actions are exempt from review under Executive Order 12866;
C. Paperwork Reduction Act (PRA)
This rule does not impose an information collection burden under the provisions of the PRA of 1995 (44 U.S.C. 3501 et seq. ). This action does not contain any information collection activities and serves only to accept comment on a determination that the St. Louis nonattainment area failed to attain the 2015 ozone standards by the August 3, 2024, Moderate area attainment date.
D. Regulatory Flexibility Act (RFA)
I certify that this action will not have a significant economic impact on a substantial number of small entities under the RFA (5 U.S.C. 601 et seq. ). This action will not impose any requirements on small entities. A determination of failure to attain the 2015 ozone standards (and resulting reclassifications), will not in and of itself create any new requirements beyond what is mandated by the CAA. This action would not itself directly regulate any small entities.
E. Unfunded Mandates Reform Act (UMRA)
This action does not contain any unfunded mandate as described in UMRA, 2 U.S.C. 1531-1538 and does not significantly or uniquely affect small governments. This action does not impose additional requirements beyond those imposed by state law. Accordingly, no additional costs to State, local, or tribal governments, or to the private sector, will result from this action.
F. Executive Order 13132: Federalism
This action does not have federalism implications. It will not have substantial direct effects on the states, on the relationship between the national government and the states, or on the distribution of power and responsibilities among the various levels of government. The division of responsibility between the Federal government and the states for purposes of implementing the NAAQS is established under the CAA.
G. Executive Order 13175: Consultation and Coordination With Indian Tribal Governments
[top] Executive Order 13175 (65 FR 67249, November 9, 2000), requires the EPA to develop an accountable process to ensure "meaningful and timely input by Tribal officials in the development of regulatory policies that have Tribal implications." This action does not have Tribal implications as specified in Executive Order 13175. This action does not apply on any Indian reservation land, any other area where EPA or an Indian tribe has demonstrated that a
H. Executive Order 13045: Protection of Children From Environmental Health and Safety Risks
The EPA interprets Executive Order 13045 (62 FR 19885, April 23, 1997) as applying to those regulatory actions that concern environmental health or safety risks that the EPA has reason to believe may disproportionately affect children, per the definition of "covered regulatory action" in section 2-202 of the Executive Order. This action is not subject to Executive Order 13045 because it does not establish an environmental standard intended to mitigate health or safety risks.
I. Executive Order 13211: Actions That Significantly Affect Energy Supply, Distribution, or Use
This action is not subject to Executive Order 13211 (66 FR 28355, May 22, 2001) because it is not a significant regulatory action under Executive Order 12866.
J. National Technology Transfer and Advancement Act (NTTAA)
This rulemaking does not involve technical standards. Therefore, the EPA is not considering the use of any voluntary consensus standards.
List of Subjects in 40 CFR Part 81
Environmental protection, Air pollution control, Intergovernmental relations, Nitrogen dioxide, Ozone, Reporting and recordkeeping requirements, Volatile organic compounds.
Dated: June 2, 2025.
Edward H. Chu,
Acting Regional Administrator, Region 7.
[FR Doc. 2025-11304 Filed 6-18-25; 8:45 am]
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