🌬️EPA Proposes Revisions to Missouri Air Quality Standards
The Environmental Protection Agency (EPA) is proposing to approve revisions to the Missouri State Implementation Plan (SIP) related to Definitions and Common Reference Tables used in Missouri rules. EPA has also previously approved this rule as part of the air planning and permitting program. Some of the definitions are associated with those programs, even though many of the definitions pertain only to the SIP. These revisions do not impact the stringency of the SIP or have an adverse effect on air quality. The EPA's proposed approval of this rule revision is being done in accordance with the requirements of the Clean Air Act (CAA).
Learn More🌬️EPA Air Plan Approval
The Environmental Protection Agency (EPA) is updating the regulatory materials that are incorporated by reference into the Idaho State Implementation Plan (SIP). The EPA is also notifying the public of corrections and clarifying changes in the Code of Federal Regulations tables that identify the regulatory materials incorporated by reference into the Idaho SIP. This update affects the materials that are available for public inspection at the National Archives and Records Administration and the EPA Region 10 Office.
Learn More🌫️Proposed Missouri Rule for Sulfur Dioxide Emissions Compliance
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<INF>2</INF>) rule in the SIP with the latest version of a newer SO<INF>2</INF> 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 This action would result in a number of changes to the SIP, including removing outdated requirements as a result of facilities that have historically closed or switched from coal to lower sulfur fuels, as well as those that have become subject to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<INF>2</INF> requirements elsewhere in the Missouri SIP. Other revisions include reinstating SO<INF>2</INF> 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.
Learn More🌬️New EPA Delegation of NSPS and NESHAP to Louisiana
The Louisiana Department of Environmental Quality (LDEQ) has submitted updated regulations for receiving delegation and approval of its program for the implementation and enforcement of certain New Source Performance Standards (NSPS) and National Emission Standards for Hazardous Air Pollutants (NESHAP) for all sources, as provided for under previously approved delegation mechanisms. The updated State regulations incorporate by reference certain NSPS and NESHAP promulgated by the Environmental Protection Agency (EPA), as they existed through July 1, 2021. EPA is providing notice that it is updating the delegation of certain NSPS to LDEQ and proposing to approve the delegation of certain NESHAP to LDEQ. The proposed delegation of authority under this action does not apply to sources located in Indian country.
Learn More🌍EPA Delegates NESHAP Authority to Oklahoma for Air Quality Management
The Oklahoma Department of Environmental Quality (ODEQ) has submitted updated regulations for receiving delegation and approval of its program for the implementation and enforcement of certain National Emission Standards for Hazardous Air Pollutants (NESHAP) for all sources, as provided for under previously approved delegation mechanisms. The updated State regulations incorporate by reference certain NESHAP promulgated by the Environmental Protection Agency (EPA), as they existed through June 30, 2022. The EPA is providing notice that it is taking final action to approve the delegation of certain NESHAP to ODEQ. The final delegation of authority under this action applies to sources located in certain areas of Indian country as discussed herein.
Learn More🌫️Air Plan Approval in Texas and Oklahoma
The Environmental Protection Agency (EPA) is extending the comment period for the proposed rule "Air Plan Approval; Texas and Oklahoma; Texas Regional Haze Plans for the First and Second Implementation Periods and Five-Year Progress Report; Oklahoma Regional Haze Plan for the First Implementation Period" that was published on May 23, 2025. The proposal provided for a public comment period ending June 23, 2025. The EPA is extending the comment period to July 23, 2025.
Learn More🌍Proposed Clean Data Determination for Guam's Piti-Cabras Area
The Environmental Protection Agency (EPA) is proposing a clean data determination (CDD) for the Piti-Cabras, Guam sulfur dioxide (SO<INF>2</INF>) nonattainment area ("Piti-Cabras area") based on our determination that the area has attained the 2010 1-hour SO<INF>2</INF> National Ambient Air Quality Standard (NAAQS, "standard," or "2010 SO<INF>2</INF> NAAQS"). In designated nonattainment areas where air quality data demonstrate that a NAAQS has been attained, the EPA interprets certain requirements of the Clean Air Act (CAA) as no longer applicable for so long as air quality continues to meet the standard. Under this Clean Data Policy, the EPA may issue a determination of attainment, known as a CDD, that a nonattainment area is attaining the relevant NAAQS. If finalized, this proposed CDD would suspend the obligation to submit certain attainment planning requirements for the Piti-Cabras area for as long as the area continues to attain the 2010 SO<INF>2</INF> NAAQS or until the area is formally redesignated.
Learn More🌫️California Regional Haze Plan Approval
The Environmental Protection Agency (EPA) is proposing to approve the regional haze state implementation plan (SIP) revision submitted by California on August 9, 2022 (hereinafter the "2022 California Regional Haze Plan" or "the Plan"), under the Clean Air Act (CAA) and the EPA's Regional Haze Rule for the program's second implementation period. California's SIP submission addresses the requirement that states must periodically revise their long-term strategies for making reasonable progress towards the national goal of preventing any future, and remedying any existing, anthropogenic impairment of visibility, including regional haze, in mandatory Class I Federal areas. The SIP submission also addresses other applicable requirements for the second implementation period of the regional haze program. The EPA is proposing this action pursuant to CAA sections 110 and 169A. The EPA is also withdrawing its previous proposed rule to partially approve and partially disapprove California's regional haze SIP revision as published in the Federal Register on December 19, 2024.
Learn More🌫️Indiana's Regional Haze Plan
The Environmental Protection Agency (EPA) is proposing to approve the Indiana regional haze state implementation plan (SIP) revision submitted by the Indiana Department of Environmental Management (IDEM or Indiana) on December 29, 2021, as satisfying applicable requirements under the Clean Air Act (CAA) and EPA's Regional Haze Rule (RHR) for the program's second implementation period. EPA proposes to find that IDEM's SIP submission addresses the requirement that States must periodically revise their long-term strategies for making reasonable progress towards the national goal of preventing any future, and remedying any existing, anthropogenic impairment of visibility, including regional haze, in mandatory Class I Federal areas, and also addresses other applicable requirements for the second implementation period of the regional haze program. EPA is taking this action pursuant to sections 110 and 169A of the CAA.
Learn More🌫️EPA Defers Sanctions in Colorado Ozone Nonattainment Area
In the Proposed Rules section of this Federal Register, EPA is proposing approval of portions of State Implementation Plan (SIP) submissions from the State of Colorado dated June 26, 2023, May 23, 2024, May 30, 2024, and April 2, 2025. The submissions relate to Colorado Air Quality Control Commission Regulation Number 7 (Reg. 7) and Regulation Number 26 (Reg. 26), and address Colorado's SIP obligations for the Reasonably Available Control Technology (RACT) Serious ozone nonattainment area requirement for the 2008 ozone National Ambient Air Quality Standard (NAAQS). In this action, the EPA is making an interim final determination based on that proposed approval. The effect of this interim final determination is that the imposition of sanctions that were triggered by the EPA's December 8, 2023 disapproval are now deferred. Although this action is effective on publication, the EPA will take comment on this interim final determination.
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