# Iowa.
**AGENCY:**
Environmental Protection Agency (EPA).
**ACTION:**
Final rule.
**SUMMARY:**
The Environmental Protection Agency (EPA) is taking final action to redesignate the nonattainment area in Muscatine County, Iowa to attainment for the 2010 1-hour sulfur dioxide (SO <sub>2</sub> ) National Ambient Air Quality Standard (NAAQS). The EPA is also approving Iowa's maintenance plan for the 2010 1-hour SO <sub>2</sub> NAAQS for the Muscatine nonattainment area and approving modifications to source-specific permits in the Iowa State Implementation Plan (SIP). The EPA is taking this action in accordance with the requirements of the Clean Air Act (CAA).
**DATES:**
This final rule is effective on December 18, 2025.
**ADDRESSES:**
The EPA has established a docket for this action under Docket ID No. EPA-R07-OAR-2025-0818. All documents in the docket are listed on the *https://www.regulations.gov* website. Although listed in the index, some information is not publicly available, *i.e.,* Confidential Business Information (CBI) or other information whose disclosure is restricted by statute. Certain other material, such as copyrighted material, is not placed on the internet and will be publicly available only in hard copy form. Publicly available docket materials are available through *https://www.regulations.gov* or please contact the person identified in the *FOR FURTHER INFORMATION CONTACT* section for additional information.
**FOR FURTHER INFORMATION CONTACT:**
Bethany Olson, Environmental Protection Agency, Region 7 Office, Air Quality Planning Branch, 11201 Renner Boulevard, Lenexa, Kansas 66219; telephone number: (913) 551-7905; email address: *[email protected].*
**SUPPLEMENTARY INFORMATION:**
Throughout this document “we,” “us,” and “our” refer to EPA.
**Table of Contents**
I. What is being addressed in this document?
II. Background
III. Have the requirements for approval of a SIP revision been met?
IV. What action is the EPA taking?
V. Incorporation by Reference
VI. Statutory and Executive Order Reviews
**I. What is being addressed in this document?**
The EPA is taking final action to approve a SIP revision and redesignation request submitted on November 17, 2021, by the Iowa Department of Natural Resources (IDNR). The EPA is taking the following three separate but related actions: (1) to add new or revised permits for Muscatine area sources into the Iowa SIP and remove certain air construction permits from the SIP; (2) to approve Iowa's maintenance plan for the 2010 1-hour SO <sub>2</sub> NAAQS in the Muscatine area and incorporate it into the SIP; and (3) to redesignate the Muscatine area to attainment for the 2010 1-hour SO <sub>2</sub> NAAQS.
The EPA finds that the State's submittal meets the requirements for redesignation under the CAA and the revisions do not interfere with any applicable requirement concerning attainment and reasonable further progress. The full State submission is included in the docket for this action.
**II. Background**
On June 2, 2010 (75 FR 35520), the EPA signed the revised the primary SO <sub>2</sub> NAAQS, establishing a new 1-hour standard of 75 parts per billion (ppb). Following promulgation of a new or revised NAAQS, the EPA is required by CAA section 107(d) to designate areas throughout the nation as attaining or not attaining the NAAQS, or as unclassifiable. On August 5, 2013, the EPA designated a portion of Muscatine County, Iowa, as nonattainment for the 2010 primary 1-hour SO <sub>2</sub> NAAQS (78 FR 47191), effective October 4, 2013.
Iowa submitted an attainment plan for the Muscatine area on May 26, 2016. Iowa's approved 2016 attainment plan provided a modeled attainment demonstration and the required nonattainment planning requirements for the Muscatine NAA. The attainment plan included permit conditions to reduce SO <sub>2</sub> emissions at three facilities in the NAA: Grain Processing Corporation (GPC), Muscatine Power and Water (MPW), and Monsanto Company—Muscatine (Monsanto), now Bayer CropScience LP. [^1] The conditions are contained in air construction permits issued by IDNR and were approved into the SIP as part of the attainment plan approval. [^2] The EPA issued a final approval of Iowa's attainment plan on November 17, 2020 (85 FR 73218).
[^1] The Monsanto facility in Muscatine is now under the ownership of Bayer CropScience LP. This document retains use of the Monsanto name for consistency with the Iowa submittal. Bayer CropScience L.P. assumed all construction permits for Monsanto that are relevant to this action.
[^2] 85 FR 73218, November 17, 2020.
On November 17, 2021, Iowa submitted a redesignation request and maintenance plan for the Muscatine nonattainment area for the 2010 SO <sub>2</sub> NAAQS. The submission also included modifications to SIP-approved permits for GPC, MPW, and Monsanto. The submitted permit revisions replace some specific conditions that the EPA had previously approved into the SIP for the purpose of demonstrating attainment of the SO <sub>2</sub> standard pursuant to the nonattainment requirements of sections 172, 191, and 192 of the CAA.
On January 26, 2022, the EPA proposed to determine that the Muscatine NAA attained the 2010 1-hour SO <sub>2</sub> NAAQS by the applicable attainment date of October 4, 2018 (87 FR 3958). The EPA issued a final determination of attainment by the attainment date for the 2010 1-hour SO <sub>2</sub> NAAQS on April 7, 2022 (87 FR 20329).
On August 21, 2025 (90 FR 40797), the EPA proposed to approve Iowa's 2021 redesignation request and maintenance plan for the Muscatine area for the 2010 SO <sub>2</sub> NAAQS. An explanation of the CAA requirements, a detailed analysis of the revisions, and EPA's reasons for proposing approval were provided in the notice of proposed rulemaking (NPRM) and will not be restated here.
The EPA also proposed to approve revisions to SIP-approved permits. The submitted revisions remove outdated permits, add new permits, and modify SIP-approved permits. The air construction permits include reasonably available control technology (RACT) limits for the 2010 1-hour SO <sub>2</sub> NAAQS, compliance monitoring, and recordkeeping and reporting requirements at GPC, MPW, and Monsanto. The emission limits establish the maximum permitted allowable emission rate for each emission point, and Iowa provided updated dispersion modeling in its 2021 SIP submission based on these conditions. The new and modified permits are contained in Attachments 1 through 3 of the State submittal in the docket for this action.
The requested permit revisions are as follows:
• Remove twelve GPC permits relied upon in the 2016 attainment plan for emission points (stacks) no longer in service. The GPC permit numbers are 15-A-078, 79-A-194-S2, 74-A-014-S1, 74-A-015-S2, 79-A-195-S2, 71-A-067-S4, 15-A-202, 15-A-209, 11-A-338-S1, 15-A-354, 05-A-926-S4, 75-A-087-S1.
• Remove eight permits from the SIP due to the revocation of the 24-hour and annual primary SO <sub>2</sub> NAAQS. The numbers are GPC permits 74-A-015-S, 79-A-194-S, 79-A-195-S, and 95-A-374; MPW permits 74-A-175-S and 95-A-373; and Monsanto permits 76-A-161S3 and 76-A-265S3.
• Add five new GPC permits into the SIP containing SO <sub>2</sub> RACT limits for the 2010 1-hour SO <sub>2</sub> NAAQS. The new permits are for four new stacks and one newly identified SO <sub>2</sub> emission source. The GPC permit numbers are 17-A-298, 17-A-299, 17-A-112, 19-A-515-S1, and 18-A-136.
• Replace twenty GPC permits, two MPW permits, and one Monsanto permit in the Iowa SIP that were relied upon in the 2016 attainment plan. Several revisions to GPC permits establish a Collection of Air Permits (CAP) which is a type of air construction permit issued by IDNR that combines the requirements and conditions for multiple emission points (and thus multiple permit numbers) into one document. Other revisions included changes to SO <sub>2</sub> RACT limits or updates unrelated to SO <sub>2</sub> . The modified GPC permit numbers are CAP: 80-A-149-S6, CAP: 80-A-150-S6, CAP: 85-A-031-S5, CAP: 85-A-032-S5, 91-A-068-S3, 92-A-383-S3, 92-A-385-S2, CAP: 94-A-055-S3, CAP: 94-A-061-S3, 02-A-781-S3, 02-A-782-S3, 10-A-563-S2, 15-A-200-S1, 15-A-201-S1, 15-A-213-S2, 15-A-486-S1, 15-A-326-S1, 03-A-471-S3, 06-A-1261-S2, and 15-A-199-S1. The modified MPW permits are 95-A-373-P4 and 80-A-191-P4, and the Monsanto permit is 82-A-092-P12.
The EPA's NPRM and supporting information contained in the docket were made available for public comment from August 21, 2025, to September 22, 2025. EPA received no comments on the proposal. Therefore, we are finalizing our action as proposed.
**III. Have the requirements for approval of a SIP revision been met?**
The State's 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 public notice on this SIP submission from August 20, 2021, to September 20, 2021, and held a public hearing on September 20, 2021. IDNR received and responded to written comments from two sources, and included the comments and responses in its submission. In addition, as explained above and in more detail in the technical support document (TSD) which is part of this document, the revision meets the substantive SIP requirements of the CAA, including section 110 and implementing regulations.
**IV. What action is the EPA taking?**
The EPA is taking final action to approve the redesignation of the Muscatine area from nonattainment to attainment in accordance with Iowa's November 17, 2021 request. The criteria under CAA section 107(d)(3)(E) as specific to the 2010 SO <sub>2</sub> NAAQS have been met. On this basis, the EPA is approving Iowa's redesignation request for the area and changing the legal designation of the portion of Muscatine County designated nonattainment at 40 CFR part 81 to attainment for the 2010 1-hour SO <sub>2</sub> NAAQS.
Additionally, the EPA is approving the Muscatine, Iowa 2010 SO <sub>2</sub> 1-hour NAAQS maintenance plan into the Iowa SIP under CAA section 175A. The maintenance plan demonstrates that the area will continue to maintain the 2010 1-hour SO <sub>2</sub> NAAQS for at least 10 years following redesignation and includes contingency provisions to remedy any future violations of the 2010 1-hour SO <sub>2</sub> NAAQS.
Finally, the EPA is taking final action to add new or revised permits for Muscatine area sources into the Iowa SIP and remove certain air construction permits from the SIP.
**V. Incorporation by Reference**
In this document, the EPA is finalizing regulatory text that includes incorporation by reference. In accordance with requirements of 1 CFR 51.5, the EPA is finalizing the incorporation by reference of the Iowa permits #17-A-298, #17-A-299, #19-A-515-S1, #18-A-136, #17-A-112, #80-A-149-S6, #80-A-150-S6, #85-A-031-S5, #85-A-032-S5, #91-A-068-S3, #92-A-383-S3, #92-A-385-S2, #94-A-055-S3, #94-A-061-S3, #02-A-781-S3, #02-A-782-S3, #10-A-563-S2, #15-A-200-S1, #15-A-201-S1, #15-A-213-S2, #15-A-486-S1, #15-A-326-S1, #03-A-471-S3, #06-A-1261-S2, #15-A-199-S1, #95-A-373-P4, #80-A-191-P4, and #82-A-092-P12 discussed in section II. of this preamble and as set forth below in the amendments to 40 CFR part 52. The EPA has made, and will continue to make, these materials generally available through *https://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).
Therefore, these materials have been approved by the EPA for inclusion in the State Implementation Plan, have been incorporated by reference by EPA into that plan, are fully federally enforceable under sections 110 and 113 of the CAA as of the effective date of the final rulemaking of the EPA's approval, and will be incorporated by reference in the next update to the SIP compilation. [^3]
[^3] 62 FR 27968, May 22, 1997.
Also, in this document, as described in the amendments to 40 CFR part 52 set forth below, the EPA is removing provisions of the EPA-approved permits from the Iowa SIP, which is incorporated by reference in accordance with the requirements of 1 CFR part 51. The EPA is removing Iowa permits #74-A-015-S, #79-A-194-S, #79-A-195-S, #95-A-374, #74-A-175-S, #95-A-373, #76-A-161S3, #76-A-265S3, #15-A-078, #79-A-194-S2, #71-A-067-S4, #75-A-087-S1, #74-A-014-S1, #74-A-015-S2, #79-A-195-S2, #80-A-149-S5, #80-A-150-S5, #85-A-031-S2, #85-A-032-S2, #91-A-068-S2, #92-A-383-S2, #92-A-385-S1, #94-A-055-S1, #94-A-061-S1, #02-A-781-S2, #02-A-782-S2, #10-A-563-S1, #15-A-200, #15-A-201, #15-A-202, #15-A-209, #15-A-213, #15-A-486, #15-A-326, #03-A-471-S1, #05-A-926-S4, #06-A-1261-S1, #11-A-338-S1, #15-A-354, #15-A-199, #95-A-373-P3, #80-A-191-P3, and #82-A-092-P11.
**VI. 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, 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);
• Is not subject to Executive Order 14192 (90 FR 9065, February 6, 2025) because SIP actions are exempt 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);
• 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); and
• 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 CAA.
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 rule 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).
This action is subject to the Congressional Review Act (CRA), and EPA will submit a rule report to each House of the Congress and to the Comptroller General of the United States. This action is not a “major rule” as defined by 5 U.S.C. 804(2).
Under section 307(b)(1) of the CAA, petitions for judicial review of this action must be filed in the United States Court of Appeals for the appropriate circuit by January 20, 2026. Filing a petition for reconsideration by the Administrator of this final rule does not affect the finality of this action for the purposes of judicial review nor does it extend the time within which a petition for judicial review may be filed, and shall not postpone the effectiveness of such rule or action. This action may not be challenged later in proceedings to enforce its requirements (see section 307(b)(2)).
**List of Subjects**
Environmental protection, Air pollution control, Incorporation by reference, Maintenance plan, Redesignation, Sulfur oxides.
Environmental protection, Air pollution control, Designations, Intergovernmental relations, Redesignation, Reporting and recordkeeping requirements, Sulfur oxides.
Dated: October 23, 2025.
James Macy,
Regional Administrator, Region 7.
For the reasons stated in the preamble, the EPA amends 40 CFR parts 52 and 81 as set forth below:
**PART 52—APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS**
**40 CFR Part 52**
1. The authority citation for part 52 continues to read as follows:
**Authority:**
42 U.S.C. 7401 *et seq.*
**Subpart Q—Iowa**
**40 CFR Part 52**
2. In § 52.820:
a. The table in paragraph (d) is amended by:
i. Revising the entries “(113),” “(114),” “(115),” “(116),” “(118),” “(122),” “(123),” “(124),” “(125),” “(129),” “(131),” “(132),” “(133),” “(134),” “(135),” “(136),” “(138),” “(139),” “(140),” “(153),” “(156),” “(157),” “(158),” “(160),” “(163),” “(166),” “(167),” and “(168)”; and
ii. Removing and reserving entries “(3),” “(4),” “(5),” “(6),” “(7),” “(8),” “(9),” “(10),” “(119),” “(121),” “(141),” “(148),” “(159),” “(161),” and “(162)”.
b. The table in paragraph (e) is amended by adding the entry “(57)” at the end of the table.
The revisions and addition read as follows:
§ 52.820
(d) * * *
| Name of source | Order/permit No. | State effective date | EPA approval date | Explanation |
| --- | --- | --- | --- | --- |
| | | | | |
| * * * * * * * | | | | |
| (3) Reserved | | | | |
| (4) Reserved | | | | |
| (5) Reserved | | | | |
| (6) Reserved | | | | |
| (7) Reserved | | | | |
| (8) Reserved | | | | |
| (9) Reserved | | | | |
| (10) Reserved | | | | |
| | | | | |
| * * * * * * * | | | | |
| (113) Grain Processing Corporation | 17-A-298 | 4/12/2018 | 11/18/2025, 90 FR [insert
page where the document begins] | 2010 1-hour SO
NAAQS Attainment Plan; EPA-R07-OAR-2025-0818; FRL-12901-02-R7. |
| (114) Grain Processing Corporation | 17-A-299 | 4/12/2018 | 11/18/2025, 90 FR [insert
page where the document begins] | 2010 1-hour SO
NAAQS Attainment Plan; EPA-R07-OAR-2025-0818; FRL-12901-02-R7. |
| (115) Grain Processing Corporation | 19-A-515-S1 | 12/22/2020 | 11/18/2025, 90 FR [insert
page where the document begins] | 2010 1-hour SO
NAAQS Attainment Plan; EPA-R07-OAR-2025-0818; FRL-12901-02-R7. |
| (116) Grain Processing Corporation | 18-A-136 | 5/30/2018 | 11/18/2025, 90 FR [insert
page where the document begins] | 2010 1-hour SO
NAAQS Attainment Plan; EPA-R07-OAR-2025-0818; FRL-12901-02-R7. |
| | | | | |
| * * * * * * * | | | | |
| (118) Grain Processing Corporation | 17-A-112 | 5/2/2017 | 11/18/2025, 90 FR [insert
page where the document begins] | 2010 1-hour SO
NAAQS Attainment Plan; EPA-R07-OAR-2025-0818; FRL-12901-02-R7. |
| (119) Reserved | | | | |
| | | | | |
| * * * * * * * | | | | |
| (121) Reserved | | | | |
| (122) Grain Processing Corporation | 80-A-149-S6 | 2/21/2017 | 11/18/2025, 90 FR [insert
page where the document begins] | 2010 1-hour SO
NAAQS Attainment Plan; EPA-R07-OAR-2025-0818; FRL-12901-02-R7. |
| (123) Grain Processing Corporation | 80-A-150-S6 | 2/21/2017 | 11/18/2025, 90 FR [insert
page where the document begins] | 2010 1-hour SO
NAAQS Attainment Plan; EPA-R07-OAR-2025-0818; FRL-12901-02-R7. |
| (124) Grain Processing Corporation | 85-A-031-S5 | 5/19/2020 | 11/18/2025, 90 FR [insert
page where the document begins] | 2010 1-hour SO
NAAQS Attainment Plan; EPA-R07-OAR-2025-0818; FRL-12901-02-R7. |
| (125) Grain Processing Corporation | 85-A-032-S5 | 5/19/2020 | 11/18/2025, 90 FR [insert
page where the document begins] | 2010 1-hour SO
NAAQS Attainment Plan; EPA-R07-OAR-2025-0818; FRL-12901-02-R7. |
| | | | | |
| * * * * * * * | | | | |
| (129) Grain Processing Corporation | 91-A-068-S3 | 11/4/2019 | 11/18/2025, 90 FR [insert
page where the document begins] | 2010 1-hour SO
NAAQS Attainment Plan; EPA-R07-OAR-2025-0818; FRL-12901-02-R7. |
| | | | | |
| * * * * * * * | | | | |
| (131) Grain Processing Corporation | 92-A-383-S3 | 10/11/2016 | 11/18/2025, 90 FR [insert
page where the document begins] | 2010 1-hour SO
NAAQS Attainment Plan; EPA-R07-OAR-2025-0818; FRL-12901-02-R7. |
| (132) Grain Processing Corporation | 92-A-385-S2 | 10/11/2016 | 11/18/2025, 90 FR [insert
page where the document begins] | 2010 1-hour SO
NAAQS Attainment Plan; EPA-R07-OAR-2025-0818; FRL-12901-02-R7. |
| (133) Grain Processing Corporation | 94-A-055-S3 | 5/13/2021 | 11/18/2025, 90 FR [insert
page where the document begins] | 2010 1-hour SO
NAAQS Attainment Plan; EPA-R07-OAR-2025-0818; FRL-12901-02-R7. |
| (134) Grain Processing Corporation | 94-A-061-S3 | 5/13/2021 | 11/18/2025, 90 FR [insert
page where the document begins] | 2010 1-hour SO
NAAQS Attainment Plan; EPA-R07-OAR-2025-0818; FRL-12901-02-R7. |
| (135) Grain Processing Corporation | 02-A-781-S3 | 2/8/2018 | 11/18/2025, 90 FR [insert
page where the document begins] | 2010 1-hour SO
NAAQS Attainment Plan; EPA-R07-OAR-2025-0818; FRL-12901-02-R7. |
| (136) Grain Processing Corporation | 02-A-782-S3 | 2/8/2018 | 11/18/2025, 90 FR [insert
page where the document begins] | 2010 1-hour SO
NAAQS Attainment Plan; EPA-R07-OAR-2025-0818; FRL-12901-02-R7. |
| | | | | |
| * * * * * * * | | | | |
| (138) Grain Processing Corporation | 10-A-563-S2 | 7/25/2017 | 11/18/2025, 90 FR [insert
page where the document begins] | 2010 1-hour SO
NAAQS Attainment Plan; EPA-R07-OAR-2025-0818; FRL-12901-02-R7. |
| (139) Grain Processing Corporation | 15-A-200-S1 | 4/12/2018 | 11/18/2025, 90 FR [insert
page where the document begins] | 2010 1-hour SO
NAAQS Attainment Plan; EPA-R07-OAR-2025-0818; FRL-12901-02-R7. |
| (140) Grain Processing Corporation | 15-A-201-S1 | 4/12/2018 | 11/18/2025, 90 FR [insert
page where the document begins] | 2010 1-hour SO
NAAQS Attainment Plan; EPA-R07-OAR-2025-0818; FRL-12901-02-R7. |
| (141) Reserved | | | | |
| | | | | |
| * * * * * * * | | | | |
| (148) Reserved | | | | |
| | | | | |
| * * * * * * * | | | | |
| (153) Grain Processing Corporation | 15-A-213-S2 | 12/22/2020 | 11/18/2025, 90 FR [insert
page where the document begins] | 2010 1-hour SO
NAAQS Attainment Plan; EPA-R07-OAR-2025-0818; FRL-12901-02-R7. |
| | | | | |
| * * * * * * * | | | | |
| (156) Grain Processing Corporation | 15-A-486-S1 | 11/4/2019 | 11/18/2025, 90 FR [insert
page where the document begins] | 2010 1-hour SO
NAAQS Attainment Plan; EPA-R07-OAR-2025-0818; FRL-12901-02-R7. |
| (157) Grain Processing Corporation | 15-A-326-S1 | 3/4/2020 | 11/18/2025, 90 FR [insert
page where the document begins] | 2010 1-hour SO
NAAQS Attainment Plan; EPA-R07-OAR-2025-0818; FRL-12901-02-R7. |
| (158) Grain Processing Corporation | 03-A-471-S3 | 5/30/2018 | 11/18/2025, 90 FR [insert
page where the document begins] | 2010 1-hour SO
NAAQS Attainment Plan; EPA-R07-OAR-2025-0818; FRL-12901-02-R7. |
| (159) Reserved | | | | |
| (160) Grain Processing Corporation | 06-A-1261-S2 | 12/22/2020 | 11/18/2025, 90 FR [insert
page where the document begins] | 2010 1-hour SO
NAAQS Attainment Plan; EPA-R07-OAR-2025-0818; FRL-12901-02-R7. |
| (161) Reserved | | | | |
| (162) Reserved | | | | |
| (163) Grain Processing Corporation | 15-A-199-S1 | 1/11/2021 | 11/18/2025, 90 FR [insert
page where the document begins] | 2010 1-hour SO
NAAQS Attainment Plan; EPA-R07-OAR-2025-0818; FRL-12901-02-R7. |
| | | | | |
| * * * * * * * | | | | |
| (166) Muscatine Power and Water | 95-A-373-P4 | 6/1/2016 | 11/18/2025, 90 FR [insert
page where the document begins] | 2010 1-hour SO
NAAQS Attainment Plan; EPA-R07-OAR-2025-0818; FRL-12901-02-R7. |
| (167) Muscatine Power and Water | 80-A-191-P4 | 6/1/2016 | 11/18/2025, 90 FR [insert
page where the document begins] | 2010 1-hour SO
NAAQS Attainment Plan; EPA-R07-OAR-2025-0818; FRL-12901-02-R7. |
| (168) Monsanto | 82-A-092-P12 | 11/1/2016 | 11/18/2025, 90 FR [insert
page where the document begins] | 2010 1-hour SO
NAAQS Attainment Plan; EPA-R07-OAR-2025-0818; FRL-12901-02-R7. |
| | | | | |
| * * * * * * * | | | | |
(e) * * *
| Name of nonregulatory SIP provision | Applicable geographic or nonattainment area | State submittal date | EPA Approval date | Explanation |
| --- | --- | --- | --- | --- |
| | | | | |
| * * * * * * * | | | | |
| (57) 2010 1-hour primary SO
NAAQS Maintenance Plan | A portion of Muscatine County | 11/17/2021 | 11/18/2025, 90 FR [insert
page where the document begins] | EPA-R07-OAR-2025-0818; FRL-12901-01-R7. |
**40 CFR Part 52**
3. In § 52.834, add paragraph (c) to read as follows:
§ 52.834
(c) *Redesignation to attainment.* EPA has determined, as of November 18, 2025, that the Muscatine County 2010 SO <sub>2</sub> nonattainment area is redesignated to attainment of the 2010 SO <sub>2</sub> 1-hour National Ambient Air Quality Standard (NAAQS) in accordance with the requirements of Clean Air Act (CAA) section 107(d)(3) and has approved its maintenance plan and supplemental modeling demonstration analyses as meeting the requirements of CAA section 175A.
**PART 81—DESIGNATION OF AREAS FOR AIR QUALITY PLANNING PURPOSES**
**40 CFR Part 81**
4. The authority citation for part 81 continues to read as follows:
**Authority:**
42 U.S.C. 7401, *et seq.*
**Subpart C—Section 107 Attainment Status Designations**
**40 CFR Part 81**
5. In § 81.316, the table entitled “Iowa—2010 Sulfur Dioxide NAAQS [Primary]” is amended by revising the entry “Muscatine, IA” to read as follows:
§ 81.316
| Designated area | Designation | Date | Type |
| --- | --- | --- | --- |
| Muscatine, IA | 11/18/2025 | Attainment. | |
| Muscatine County (part) | | | |
| Sections 1-3, 10-15, 22-27, 34-36 of T77N, R3W (Lake Township) | | | |
| Sections 1-3, 10-15, 22-27, 34-36 of T76N, R3W (Seventy-six Township) | | | |
| T77N, R2W (Bloomington Township) | | | |
| T76N, R2W (Fruitland Township) | | | |
| All sections except 1, 12, 13, 24, 25, 36 of T77N, R1W (Sweetland Township) | | | |
| | | | |
| * * * * * * * | | | |