90 FR 122 pgs. 27491-27496 - Air Plan Approval; Missouri; Control of Sulfur Dioxide Emissions and Approval and Promulgation of State Plan (Negative Declaration) for Designated Facilities and Pollutants
Type: PRORULEVolume: 90Number: 122Pages: 27491 - 27496
Pages: 27491, 27492, 27493, 27494, 27495, 27496Docket number: [EPA-R07-OAR-2025-0263; FRL-12807-01-R7]
FR document: [FR Doc. 2025-11825 Filed 6-26-25; 8:45 am]
Agency: Environmental Protection Agency
Official PDF Version: PDF Version
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Parts 52 and 62
[EPA-R07-OAR-2025-0263; FRL-12807-01-R7]
Air Plan Approval; Missouri; Control of Sulfur Dioxide Emissions and Approval and Promulgation of State Plan (Negative Declaration) for Designated Facilities and Pollutants
AGENCY:
Environmental Protection Agency (EPA).
ACTION:
Proposed rule.
SUMMARY:
The EPA is proposing to approve revisions to the Missouri State Implementation Plan (SIP) submitted by the State of Missouri. Missouri requests that EPA approve replacing the previous statewide sulfur dioxide (SO 2 ) rule in the SIP with the latest version of a newer SO 2 rule (10 CSR 10-6.261). This action would result in a number of changes to the SIP, including removing outdated requirements as a result of facilities that have historically closed or switched from coal to lower sulfur fuels, as well as those that have become subject to more stringent SO 2 requirements elsewhere in the Missouri SIP. Other revisions include reinstating SO 2 emission limits for the Ameren-Labadie and Evergy-Hawthorn power plants that had been previously removed. The revisions do not impact the stringency of the SIP, nor do they impact the state's ability to attain or maintain the National Ambient Air Quality Standards (NAAQS). In conjunction with proposing approval of revisions to the Missouri SIP, the EPA is proposing to approve Missouri's negative declaration of sources subject to sulfuric acid production requirements submitted by the MoDNR to the EPA on May 4, 2022.
DATES:
Comments must be received on or before July 28, 2025.
ADDRESSES:
You may send comments, identified by Docket ID No. EPA-R07-OAR-2025-0263 to https://www.regulations.gov. Follow the online instructions for submitting comments.
Instructions: All submissions received must include the Docket ID No. EPA-R07-OAR-2025-0263 for this rulemaking. Comments received will be posted without change to 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 preamble.
FOR FURTHER INFORMATION CONTACT:
Wendy Vit, Environmental Protection Agency, Region 7 Office, Air-Analysis, Grants, Partnership Programs, 11201 Renner Boulevard, Lenexa, Kansas 66219; telephone number: (913) 551-7697; email address: vit.wendy@epa.gov.
SUPPLEMENTARY INFORMATION:
Throughout this document "we," "us," and "our" refer to the EPA.
Table of Contents
I. Written Comments
II. What is being addressed in this document?
III. What is EPA's analysis of the rule revisions?
A. Exemption for Ultra Low Sulfur Diesel
B. Rule Provisions Linked to State's Historical CAA 111(d) Plan for Sulfuric Acid Production
C. Non-Named Indirect Heating Sources
D. Facility-Specific SO 2 Emission Limits
1. SO 2 Emission Limits in 6.261 Table 1
2. SO 2 Emission Limits Not Included in Rule
3. Summary of EPA's Analysis of Revisions to Facility-specific SO 2 Emission Limits
E. Reporting, Recordkeeping, and Testing Requirements
IV. Negative Declaration for 111(d) Requirements for Sulfuric Acid Production
V. Have the requirements for approval of a SIP revision been met?
VI. What action is the EPA taking?
[top] VII. Incorporation by Reference
VIII. Statutory and Executive Order Reviews
I. Written Comments
Submit your comments, identified by Docket ID No. EPA-R07-OAR-2025-0263, at https://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 https://www.epa.gov/dockets/commenting-epa-dockets.
II. What is being addressed in this document?
The EPA is proposing to approve revisions to the Missouri SIP received on April 23, 2025. In its submission, the MoDNR requested rescinding 10 CSR 10-6.260 "Restriction of Emission of Sulfur Compounds" and replacing it with a newer statewide regulation, 10 CSR 10-6.261 "Control of Sulfur Dioxide Emissions" (state effective date May 30, 2025) in the Missouri SIP. At the same time, we are proposing to approve Missouri's negative declaration pursuant to the state's approved Clean Air Act (CAA) 111(d) plan for Sulfuric Acid Mist from Existing Sulfuric Acid Production Plants, which is codified at 40 CFR 62.6353. The negative declaration is necessary for Missouri to remove portions of 10 CSR 10-6.260 that are linked to the state's 111(d) plan for sulfuric acid production.
10 CSR 10-6.260 was originally approved into the SIP at 40 CFR 52.1320(c) in 1998 (63 FR 45727, August 27, 1998) and has been revised in the SIP several times. 1 A portion of 6.260, subsection (3)(A), was solely approved pursuant to the state's 111(d) plan for sulfuric acid production and has never been in the Missouri SIP. 10 CSR 10-6.261 was initially put in place in the Missouri Code of State Regulations (CSR) with an effective date of November 30, 2015, concurrent with the removal of 6.260 from the CSR. Although 6.261 has been revised several times in the Missouri CSR, it has never been approved into the Missouri SIP. On March 7, 2019, Missouri submitted the previous version of 6.261 (state effective date March 30, 2019) and requested that it replace 6.260 in the SIP. However, on January 4, 2023, the EPA finalized disapproval of the requested SIP revision because the state had not demonstrated that the removal of SO 2 emission limits for the Hawthorn and Labadie power plants from the SIP would not interfere with NAAQS attainment and reasonable further progress (RFP), or any other applicable requirement of the CAA. 2 Missouri subsequently revised 6.261 by restoring the Hawthorn and Labadie SO 2 limits from 6.260, as well as making a number of other changes. This most recent revision of 6.261 with a state effective date May 30, 2025, was submitted to the EPA on April 23, 2025 and is the subject of this proposed approval action. Specifically, we are proposing to find that reinstating the Hawthorn and Labadie SO 2 emission limits from 6.260 into 6.261 addresses the deficiencies identified in the EPA's January 4, 2023 disapproval action. In addition, we are proposing to approve replacing 6.260 with 6.261 in the Missouri SIP, as well as approve Missouri's negative declaration in lieu of the 111(d) plan for sulfuric acid production.
Footnotes:
1 ?See 71 FR 12623 (March 13, 2006), 73 FR 35071 (June 20, 2008), and 78 FR 69995 (November 22, 2013).
2 ?See 88 FR 292 (January 4,2023).
In order for the EPA to fully approve a SIP revision, the SIP revision must meet the requirements of CAA section 110(l), 42 U.S.C. 7410(l). Under CAA section 110(l), the EPA may not approve a SIP revision that would interfere with any applicable requirement concerning NAAQS attainment and Reasonable Further Progress (RFP), or any other applicable requirement of the CAA. Missouri submitted a CAA section 110(l) demonstration in support of their requested SIP revisions, which is included in the docket for this action. Our analysis of the key SIP revisions and Missouri's section 110(l) demonstration can be found in section III of this preamble. The EPA's technical support document (TSD) included in this docket provides greater detail.
10 CSR 10-6.261 contains SO 2 emissions limits and requirements that were in place prior to the 2010 1-hour SO 2 NAAQS; it does not include requirements relied on for meeting 2010 1-hour SO 2 NAAQS requirements in the Missouri's nonattainment and maintenance areas that were previously approved into Missouri's SIP. 3
Footnotes:
3 ?Requirements to comply with the 2010 SO 2 NAAQS in the state's maintenance areas are contained in SIP-approved consent agreements with Vicinity (formerly Veolia) and Ameren. Vicinity's consent agreement was approved into the SIP in conjunction with the redesignation of the Jackson County, Missouri SO 2 nonattainment area (87 FR 4812, January 31, 2022). Ameren's consent agreement, which includes requirements for the Meramec, Rush Island, and Labadie power plants, was approved into the SIP as part of the redesignation of the Jefferson County, Missouri SO 2 nonattainment area (87 FR 4508, January 28, 2022). In addition, on May 3, 2023, Missouri submitted an attainment plan for the New Madrid County, MO SO 2 nonattainment area to EPA, including consent agreements with Magnitude 7 Metals and AECI.
III. What is EPA's analysis of the rule revisions?
This section summarizes the EPA's analysis of 10 CSR 10-6.260 in the Missouri SIP? 4 and the state's 111(d) plan for sulfuric acid production compared to the version of 10 CSR 10-6.261 with a state effective date of May 30, 2025 submitted on April 23, 2025. The key changes are highlighted in this document, with additional detail in the EPA's TSD included in the docket for this action.
Footnotes:
4 ?10 CSR 10-6.260 is no longer in the Missouri CSR. As of the date of publication of this Federal Register publication, 6.260 in the Missouri SIP is available at https://www.epa.gov/sites/default/files/2017-09/documents/10-6260.pdf. As noted in the summary of EPA rulemakings following the text of 6.260 posted at this link, (3)(A)1. through (3)(A) 4. of 6.260 are not included in the SIP and are approved pursuant to CAA 111(d) only.
A. Exemption for Ultra Low Sulfur Diesel
[top] Compared to the clean fuel exemption in 6.260 paragraph (1)(A)2., 6.261 subsection (1)(A) maintains exemptions for units that burn natural gas or liquified petroleum gas, plus adds an exemption for units that burn ultra-low sulfur diesel (ULSD) with a sulfur content no greater than 15 parts per million (ppm). As discussed further in the EPA's TSD, a sulfur content of 15 ppm is equivalent to 0.0015 weight percent (wt%) sulfur, which is less than the rule's most stringent fuel oil sulfur content limit of 2 wt%. In addition, 15 ppm equates to an SO 2 emission rate of 0.0016 pounds per million British thermal units (lb/MMBtu), which is well below the most stringent SO 2 emission rate limit of 2.3 lb/MMBtu for non-named indirect heating sources ( i.e., sources without facility-specific limits listed in Table 1) in 6.261. Based on our analysis, we are proposing to find that adding a rule exemption for units burning ULSD with a sulfur content of no greater that 15 ppm does not reduce the stringency of the SIP and therefore
B. Rule Provisions Linked to State's Historical CAA 111(d) Plan for Sulfuric Acid Production
6.260 subsection (3)(A) contains stack gas concentration limits for existing sources of 70 micrograms per cubic meter (mg/m 3 ) of sulfuric acid or sulfur trioxide and 2,000 parts per million by volume (ppmv) of SO 2 , and limits for new sources of 35 mg/m 3 of sulfuric acid or sulfur trioxide and 500 ppmv of SO 2 . 6.260 subsection (1)(B) specifies that these limits apply to non-indirect heating sources. The limits in 6.260 subsection (3)(A) are not retained in 6.261 because they were in place pursuant to Missouri's CAA 111(d) plan for sulfuric acid production, and there are no longer any sources subject to these requirements. Accordingly, 6.261 removes non-indirect heating sources and any non-SO 2 sulfur compound emissions from section (1) rule applicability. With approval of Missouri's negative declaration for affected sulfuric acid production sources concurrent with this action, EPA is proposing to find that it is not necessary to include the SO 2 , sulfuric acid, and sulfur trioxide limits from 6.260(3)(A) in 6.261 and that it is appropriate to remove non-indirect heating sources from rule applicability. Missouri's negative declaration for sources subject to CAA 111(d) sulfuric acid production requirements is discussed in section IV of this preamble.
C. Non-Named Indirect Heating Sources
Although provisions addressing indirect heating sources that are not identified by name were reorganized and clarified in 6.261, general applicability and SO 2 emission limitations for these non-named indirect heating sources does not change from 6.260 to 6.261. Specifically, non-named indirect heating sources with actual heat input greater than 350,000 British thermal units per hour (Btu/hour) continue to be subject to 6.261. In addition, the SO 2 emission rate limits for non-named indirect heating sources subject to 6.261 are the same as the limits for these sources in 6.260. These SO 2 emission rate limits are as follows: 2.3 lb/MMBtu in Franklin, Jefferson, St. Louis, and St. Charles Counties, and the City of St. Louis; and 8 lb/MMBtu for the rest of the state. Also retained in 6.261 are seasonal coal and fuel oil sulfur content limits from 6.260 for non-named indirect heating sources located in St. Louis area counties that have heat input capacity greater than 350,000 Btu/hr (equivalent to 0.35 MMBtu/hr) and <2,000 MMBtu/hr. Because the stringency of SO 2 limits and requirements for non-named indirect heating sources does not change compared to 6.260, the EPA is proposing to approve the reorganization and clarification of provisions related to non-named indirect heating units in 6.261.
D. Facility-Specific SO 2 Emission Limits
The facility-specific SO 2 emission limits for sources listed in multiple tables in 6.260 are consolidated into 6.261 Table 1 in subsection (3)(A). The numeric SO 2 emission limits that continue to be necessary are included in 6.261 Table 1, while other limits that are no longer necessary were omitted from the rule. The two sub-sections below discuss the facility-specific SO 2 emission limits that are included in 6.261 and those that are not included in the rule. For the SO 2 emission limits listed in 6.261 Table 1, the limits are unchanged from 6.260 in the majority of cases, with the exception being for Hawthorn boiler 5A. The numeric limit for Hawthorn boiler 5A is unchanged from 6.260, however, 6.261 contains new language that ensures a continuous SO 2 limit is in place for this unit during periods of startup and shutdown as discussed further below.
1. SO 2 Emission Limits in 6.261 Table 1
The SO 2 emission rate limits of 4.8 lb/MMBtu (daily average) for Labadie and 0.12 lb/MMBtu (30-day rolling average) for Hawthorn boiler 5A from 6.260 are reinstated in 6.261 Table 1 following the EPA's disapproval of the previous version of 6.261 (state effective date March 30, 2019) which did not include them. 5 Regarding the Hawthorn limit of 0.12 lb/MMBtu, 6.260 Table 1 included a footnote that stated the limit comes from the Prevention of Significant Deterioration (PSD) permit for boiler 5A and is implemented in accordance with the terms of the permit. 6 The 0.12 lb/MMBtu SO 2 limit for boiler 5A in Hawthorn's PSD permit excludes periods of startup, shutdown, and emergencies. When the Hawthorn limit of 0.12 lb/MMBtu was added back to 6.261 Table 1, new language was also inserted stating that this limit excludes periods of startup and shutdown. Because this new language in 6.261 Table 1 does not reference emergency situations, the SO 2 emission rate limit of 0.12 lb/MMBtu limit is applicable during emergencies. Footnote (d) was also added for this limit in 6.261 Table 1 specifying that natural gas must be used for startup of Hawthorn boiler 5A, and once the unit converts to firing coal, the dry scrubber must be started appropriately to comply with relevant standards applicable during normal operation. Footnote (d) further states that during shutdown, the dry scrubber must be operated after coal stops being fed in the unit for as long as possible thereafter. The EPA is proposing to find the above limits for Hawthorn boiler 5A are protective of the NAAQS given the requirement to burn natural gas during startup and the requirement to run the scrubber during shutdown, as this ensures a continuous limit is in place.
Footnotes:
5 ?See 88 FR 291, January 4, 2023.
6 ?Construction Permit #888 issued August 17, 1999 (amended February 15, 2001).
As noted above, the numeric limit for Hawthorn originated in a PSD permit which included the numeric limit as well as the associated monitoring, recordkeeping, and reporting (MRR) requirements. Those MRR requirements were not previously included in 6.260 and accordingly were not in the SIP. However, the necessary MRR for Hawthorn's limit will be incorporated into the SIP as part of our action on 6.261. 6.261 subsection (3)(C) specifies the required compliance demonstrations for this rulemaking which includes Continuous Emissions Monitoring Systems (CEMS) and performance testing depending on the fuel type. This rule provides CEMS operating specifications and performance testing requirements under 6.261 section (5). Per the Hawthorn Title V Operating Permit, SO 2 CEMS are required for boiler 5A. CEMS is used to show compliance with the 0.12 lb/MMBtu SO 2 emission rate limit for Hawthorn boiler 5A. In addition, 6.261 section (4) contains requirements for the facility to maintain data from CEMS used to show compliance with the rule for a minimum of five years. Because the numeric limit and the necessary MRR are now fully contained in the state rule which will be incorporated into the SIP via this action, Missouri has addressed any potential deficiencies in the SIP with respect to Hawthorn and has enhanced the enforceability and protectiveness of the limit that was previously approved into the SIP.
[top] Other facilities retained in 6.261 Table 1 with no change to their SO 2 emission limits from 6.260 include: Associated Electric Cooperative (AECI)-New Madrid and Thomas Hill power plants, University of Missouri-Columbia
2. SO 2 Emission Limits Not Included in Rule
The following facilities with SO 2 limits in 6.260 are not included in 6.261 Table 1 because they have ceased operating their coal-burning equipment or have permanently closed: Central Electric Power Cooperative-Chamois, Empire District Electric Company-Asbury Station, Independence Power and Light-Blue Valley Station, Kansas City Power and Light-Montrose Station, Aquila-Sibley Plant, and Doe Run Company-Herculaneum Smelter. 7 As part of Missouri's CAA section 110(l) demonstration included in the docket for this action, Missouri provided documentation regarding the cessation of operation of these facilities, including permit termination letters, inspection reports, a retired unit acid rain exemption form, and permanent retirement letters. Based on our review, we are proposing to find that not including these limits in 6.261 Table 1 does not reduce the stringency of the SIP and therefore does not interfere with any applicable requirement concerning attainment and reasonable further progress or any other applicable requirement of the CAA, in accordance with section 110(l) of the CAA.
Footnotes:
7 ?Doe Run Company-Herculaneum Smelter ceased all primary lead smelting operations in December 2013, per 2011 federal Consent Agreement (Case: 4:10-cv-01895-JCH Doc. #: 116 Signed: 12/21/11).
The following facilities are not included in 6.261 Table 1 because they meet the rule's exemptions or are subject to a permanent and federally enforceable SO 2 limit that is equivalent to or more stringent than the limit in 6.260: City Utilities-James River Plant, Trigen-Grand Avenue Plant (now Vicinity), Aquila-Lake Road Plant (now Evergy-Lake Road), Ameren-Sioux Plant, and Doe Run Company-Glover. City Utilities-James River replaced five coal-fired boilers with two natural gas/fuel oil fired combustion turbines, which meet the rule's exemptions for burning clean fuels, as well as being subject to a more stringent SO 2 emission limit, as specified in 6.261 subsections (1)(A) and (1)(C), respectively. 8 The Vicinity, Lake Road, Ameren-Sioux, and Doe Run-Glover facilities operate under Consent Agreements approved in Missouri's SIP with SO 2 emission limits that are more stringent than the limits from 10 CSR 10-6.260. 9
Footnotes:
8 ?10 CSR 10-6.261(1)(C)1. exempts units subject to more restrictive SO 2 emission limits or fuel sulfur content standards under 10 CSR 10-6.070, which is Missouri's state rule that incorporates by reference New Source Performance Standards in 40 CFR part 60. The combustion turbines at the James River power plant are subject to sulfur limits under 40 CFR part 60, subpart GG, Standards of Performance for Stationary Gas Turbines.
9 ?Vicinity's consent agreement was approved into Missouri's SIP in conjunction with the redesignation of the Jackson County, Missouri SO 2 nonattainment area to attainment on January 31, 2022 (87 FR 4812). Evergy-Lake Road's Consent Agreement was last approved into the SIP on July 3, 2023 (88 FR 46240). The Consent Agreement for Ameren-Sioux was approved into the SIP on November 16, 2022 (87 FR 68634). Doe Run-Glover's Consent Agreement was approved into the SIP on April 27, 2022 (87 FR 24870).
3. Summary of EPA's Analysis of Revisions to Facility-Specific SO 2 Emission Limits
Based on our analysis, we are proposing to find that the revisions to the facility-specific SO 2 emission rate limits in 6.261 Table 1 do not interfere with any applicable requirement concerning attainment and reasonable further progress or any other applicable requirement of the CAA, in accordance with section 110(l) of the CAA. Reinstating the limits for Labadie and Hawthorn addresses the deficiencies identified in our previous disapproval of 6.261. Regarding the Hawthorn limit, the addition of footnote (d) to 6.261 Table 1 specifying use of natural gas during startup and operation of the scrubber during shutdown periods minimizes SO 2 emissions and ensures a continuous SO 2 emission limit is in place that is consistent with the facility's Title V Operating Permit. In addition, inclusion of monitoring, recordkeeping and reporting requirements in the SIP-approved rule will result in a more enforceable and protective limit for Hawthorn than previously included in the SIP. The facility-specific SO 2 limits from 6.260 that have not been retained in 6.261 are either subject to more stringent SO 2 requirements elsewhere in the Missouri SIP or are no longer applicable because the coal-burning equipment has been dismantled or the facility has ceased operating altogether. For these reasons, we are proposing to approve the revisions to the facility-specific SO 2 emissions limits in 6.261 Table 1.
E. Reporting, Recordkeeping, and Testing Requirements
Other revisions to 6.261 include consolidating and clarifying reporting and recordkeeping requirements in section (4) and CEMS and test method specifications in section (5), removing duplicative requirements, as well as making a number of other clarifications and corrections. The applicability of reporting and recordkeeping requirements in 6.261 section (4) for excess emissions is expanded to all sources subject to 6.261, with the exception of startup, shutdown, and malfunction emissions (SSM) which are covered under a separate rule in the Missouri SIP, 10 CSR 10-6.050 Start-Up, Shutdown, and Malfunction Conditions. In 6.260, only certain non-named indirect heating sources located in the St. Louis area counties and secondary lead smelters were subject to the rule's excess emissions reporting requirements. 6.261 section (4) also expands on the recordkeeping requirements in 6.260 to include more detail on records that must be maintained. In 6.261 section (5) test methods, the revisions provide greater clarify on specific SO 2 testing and CEMS requirements. New language also allows for alternative test methods that have been reviewed by EPA and approved into the SIP. The EPA is proposing to determine that changes to record keeping and reporting and testing requirements do not reduce the stringency of the SIP therefore do not interfere with any applicable requirement concerning attainment and reasonable further progress or any other applicable requirement of the CAA, in accordance with section 110(l) of the CAA.
IV. Negative Declaration for 111(d) Requirements for Sulfuric Acid Production
[top] The CAA delineates regulations for air pollution emissions that can adversely impact public health. CAA section 111 requires the EPA establish standards of performance for certain categories of stationary sources that, in the Administrator's judgment, "cause, or contribute significantly to, air pollution which may reasonably be anticipated to endanger public health or welfare." Under CAA section 111(d), EPA has issued emission guidelines (EGs) regulating five pollutants from six source categories that are currently in effect [sulfuric acid plants (acid mist), phosphate fertilizer plants (fluorides), primary aluminum plants (fluorides), kraft pulp plants (total reduced sulfur), municipal solid waste landfills (landfill gases), and fossil fuel-fired electric generating units (greenhouse gases)]. CAA section 111(d) in conjunction with CAA section 111(a)(1) establishes and defines roles and responsibilities for both the EPA and the states in the regulation of designated facilities. States use the EPA's standards of performance as the basis for establishing requirements for designated facilities in their state implementation plans. The states submit their plans to the EPA, and the EPA must evaluate each state plan. If a state has no designated facilities for
40 CFR part 62 lists the state plans for control of pollutants and facilities under section 111(d) and section 129 of the CAA. The State of Missouri's approved plan for Sulfuric Acid Mist from Existing Sulfuric Acid Productions Plants is codified at 40 CFR 62.6353. As stated in 40 CFR 62.6353, in Missouri, 111(d) sulfuric acid production requirements have historically applied to a single plant, W.R. Grace and Company in Joplin, Missouri. The regulation was initially approved and codified into the CFR on March 14, 1986. 10 The enforceable SO 2 and sulfuric acid limitations for the 111(d) plan were originally included in an old state rule, 10 CSR 10-3.100, Restriction of Emission of Sulfur Compounds, section (4). In the late 1990s, MoDNR consolidated several sulfur rules covering different parts of the state into a single statewide rule 10 CSR 10-6.260 and rescinded the older sulfur rules from the Missouri CSR at the same time. As part of this sulfur rule consolidation effort, the SO 2 and sulfuric acid limitations associated with the 111(d) plan in 3.100(4) were moved into 6.260. EPA's approval of the original version of 6.260 into the Missouri SIP specifies that the SO 2 and sulfuric acid limits moved into 6.260 from 3.100 section (4) were approved pursuant to 111(d) requirements and were not approved into the SIP. 11 In a subsequent revision to 6.260, these limits were moved to subsection (3)(A).
Footnotes:
10 ?See 51 FR 8828, Mar. 14, 1986, as amended at 63 FR 45729, Aug. 27, 1998; 71 FR 12626, Mar. 13, 2006; 79 FR 14616, Mar. 17, 2014; 80 FR 11580, Mar. 4, 2015; 84 FR 16407, Apr. 19, 2019.
11 ?See 63 FR 45727, August 27, 1998.
MoDNR submitted a negative declaration to EPA on May 4, 2022 certifying that the existing sulfuric acid production plant specified in 40 CFR 62.6353 was no longer in operation. W.R. Grace and Company in Joplin, Missouri was the only source listed under 40 CFR 62.6353. MoDNR's negative declaration stated that an inspection conducted on the facility on January 13, 2004 determined that the facility was closed. The facility has since remained closed.
EPA is proposing to approve the negative declaration submitted by MoDNR serving in lieu of their CAA 111(d) state plan for the Sulfuric Acid Mist from Existing Sulfuric Acid Production Plants guidelines to satisfy the requirements of 40 CFR 60.23(b) and 62.06. Any new sulfuric acid production operations in Missouri would be subject to 40 CFR part 60 subpart H, Standards of Performance for Sulfuric Acid Plants, which applies to sulfuric acid production facilities constructed or modified after August 17, 1971.
V. Have the requirements for approval of a SIP revision been met?
The State submission has met the public notice requirements for SIP submissions in accordance with 40 CFR 51.102. The submission also satisfied the completeness criteria of 40 CFR part 51, appendix V. The State provided an initial 60-day public review and comment period on the Regulatory Impact Report, draft version of 10 CSR 10-6.261, and CAA section 110(l) demonstration from February 2, 2024 to April 2, 2024. The State provided an additional public notice period from November 1, 2024 to December 12, 2024 and received zero (0) comments. A public hearing was held December 5, 2024. As explained above (and in more detail in the TSD which is included in the docket for this action), the revisions proposed for approval meet the substantive SIP requirements of the CAA, including section 110 and implementing regulations.
VI. What action is the EPA taking?
We are processing this as a proposed action because we are soliciting comments on this proposed action. Final rule will occur after consideration of any comments. The State of Missouri previously conducted a public notice on the rule changes. We are publishing the proposed rulemaking in the Federal Register to approve the SIP submission and 111(d) negative declaration. Any parties interested in commenting must do so by the date listed in the DATES section of the document. For further information about commenting on this proposed rulemaking, see the ADDRESSES section of the document. The EPA is soliciting comment on the substantive and administrative revisions detailed in this proposal and the TSD. The EPA is not soliciting comment on existing rule text that has been previously approved by the EPA into the SIP. If EPA receives adverse comment, we will address all public comments in the subsequent final rule based on the proposed rulemaking.
VII. Incorporation by Reference
In this document, the EPA is proposing to include regulatory text in an EPA final rule that includes incorporation by reference. In accordance with requirements of 1 CFR 51.5, the EPA is proposing to incorporate by reference the Missouri Regulations of 10 CSR 10-6.261 Control of Sulfur Dioxide Emissions as described in section II of this preamble and set forth below in the proposed amendments to 40 CFR part 52. The EPA has made, and will continue to make, these materials generally available through www.regulations.gov and at the EPA Region 7 Office (please contact the person identified in the FOR FURTHER INFORMATION CONTACT section of this preamble for more information).
Also, in this document, as described in the proposed amendments to 40 CFR part 52 set forth below, EPA is proposing to remove provisions of the EPA-Approved Missouri Regulations and Statutes from the Missouri State Implementation Plan, which is incorporated by reference in accordance with the requirements of 1 CFR part 51.
VIII. Statutory and Executive Order Reviews
Under the CAA, the Administrator is required to approve a SIP submission that complies with the provisions of the CAA and applicable Federal regulations. 42 U.S.C. 7410(k); 40 CFR 52.02(a). Thus, in reviewing SIP submissions, the EPA's role is to approve state choices, provided that they meet the criteria of the CAA. Accordingly, this action merely approves state law as meeting Federal requirements and does not impose additional requirements beyond those imposed by state law. For that reason, this action:
• Is not a significant regulatory action subject to review by the Office of Management and Budget under Executive Orders 12866 (58 FR 51735, October 4, 1993);
• Executive Order 14192 (90 FR 9065, February 6, 2025) does not apply because actions that approve state implementation plans are exempted from review under Executive Order 12866;
• Does not impose an information collection burden under the provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq. );
• Is certified as not having a significant economic impact on a substantial number of small entities under the Regulatory Flexibility Act (5 U.S.C. 601 et seq. );
• Does not contain any unfunded mandate or significantly or uniquely affect small governments, as described in the Unfunded Mandates Reform Act of 1995 (Pub. L. 104-4);
[top] • Does not have federalism implications as specified in Executive Order 13132 (64 FR 43255, August 10, 1999);
• Is not subject to Executive Order 13045 (62 FR 19885, April 23, 1997) because it approves a state program;
• Is not a significant regulatory action subject to Executive Order 13211 (66 FR 28355, May 22, 2001);
• Is not subject to requirements of section 12(d) of the National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272 note) because application of those requirements would be inconsistent with the Clean Air Act.
In addition, the SIP is not approved to apply on any Indian reservation land or in any other area where EPA or an Indian tribe has demonstrated that a tribe has jurisdiction. In those areas of Indian country, the proposed rulemaking does not have tribal implications and will not impose substantial direct costs on tribal governments or preempt tribal law as specified by Executive Order 13175 (65 FR 67249, November 9, 2000).
List of Subjects
40 CFR Part 52
Environmental protection, Air pollution control, Carbon monoxide, Incorporation by reference, Intergovernmental relations, Lead, Nitrogen dioxide, Ozone, Particulate matter, Reporting and recordkeeping requirements, Sulfur Oxides, Volatile organic compounds.
40 CFR Part 62
Environmental protection, Administrative practice and procedure, Air pollution control, Intergovernmental relations, Reporting and recordkeeping requirements.
Dated: June 13, 2025.
James Macy,
Regional Administrator, Region 7.
For the reasons stated in the preamble, the EPA proposes to amend 40 CFR parts 52 and 62 as set forth below:
PART 52-APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS
1. The authority citation for part 52 continues to read as follows:
Authority:
42 U.S.C. 7401 et seq.
Subpart AA-Missouri
2. In §?52.1320, the table in paragraph (c) is amended by revising the entry "10 CSR 10-6.261" to read as follows:
§?52.1320 Identification of plan.
(c) * * *
| Missouri citation | Title | State effective date | EPA approval date | Explanation |
|---|---|---|---|---|
| Missouri Department of Natural Resources | ||||
| * * * * * * * | ||||
| Chapter 6-Air Quality Standards, Definitions, Sampling and Reference Methods, and Air Pollution Control Regulations for the State of Missouri | ||||
| * * * * * * * | ||||
| 10 CSR 10-6.261 | Control of Sulfur Dioxide Emissions | May 30, 2025 | [Date of publication of the final rule in the Federal Register ], 90 FR [ Federal Register page where the document begins of the final rule] | |
| * * * * * * * | ||||
PART 62-APPROVAL AND PROMULGATION OF STATE PLANS FOR DESIGNATED FACILITIES AND POLLUTANTS
3. The authority citation for part 62 continues to read as follows:
Authority:
42 U.S.C. 7401 et seq.
Subpart-AA Missouri
§?62.6350 [Amended]
4. Amend §?62.6350 by removing "Sulfuric acid production plants" and reserving paragraph(c)(2).
5. Revise §?62.6353 to read as follows:
§?62.6353 Identification of sources.
Letter from the Missouri Department of Natural Resources, submitted May 4, 2022, certifying that there are no sulfuric acid production plants in Missouri. Effective date: The revision effective date of the negative declaration and EPA withdrawal of the prior plan approval is [Date 30 days after date of publication of the final rule in the Federal Register ].
[FR Doc. 2025-11825 Filed 6-26-25; 8:45 am]
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