NOTICE OF SUBSTANTIVE CHANGE
TYPE OF FILING: Amendment
1. Agency Information
Environmental Quality, Air Quality
Multi-Agency State Office Building
Salt Lake City, UT 84114-4820
2. Contact Persons
Please address questions regarding information on this notice to the persons listed above.
3. General Information
A. Rule or section catchline:
R307-110. General Requirements: State Implementation Plan
B. Purpose of the new rule or reason for the change:
The Clean Air Act and Regional Haze Rule requires states to submit a State Implementation Plan (SIP) demonstrating reasonable progress towards achieving natural visibility by 2064 in Utah's five Class I Areas (CIAs), which include all five of the national parks in the State.
As part of this SIP, the state must conduct an emissions control determination to identify its long-term strategy (LTS) to achieve the 2064 natural conditions goal.
This rule is being amended to incorporate by reference Utah SIP Section XX.A.1: Regional Haze Second Implementation Period and amendments to SIP Section IX.H.23: Regional Haze Emissions Limits and Operating Practices.
C. Summary of the new rule or change:
This amendment changes the "most recently amended" date in Sections R307-110-17 and R307-110-28 to 11/04/2026, incorporating by reference the requirements of Section XX.A.1: Regional Haze Second Implementation Period and Section IX: Control Measures for Area and Point Sources, Part H, Emission Limits, of the Utah SIP.
The reasonable progress determinations in these sections revise Section XX.A with the following changes to measures supporting the State's LTS:
1. Establishes mass-based annual and 30-day rolling Nitrogen Oxides (NOx) emissions limits for the Intermountain Power Plant (IPP) based on a four-factor analysis and the achievable control efficiency of selective non-catalytic reduction;
2. Removes the enforceable closure date for the coal-fired boilers at the IPP due to changes in federal and state policy; and
3. Revises the compliance date for flue gas recirculation at the US Magnesium Riley boiler to 2028, or upon source startup, whichever occurs later, and updates the SIP to reflect the current operator.
4. Legislative Action Information
A. Are any changes in this filing
because of state legislative action?
Changes are because of legislative action.
B. If yes, any bill number and
session:
HB 425 (2023 General Session), SB 161 (2024 General Session), HB 3004 (2024 Special Session), HB 70 (2025 General Session)
5. Fiscal Information
Provide an estimate and written explanation of the aggregate anticipated cost or savings to:
Removal of the IPP closure date from the SIP provides the opportunity for the facility to be sold and potentially returned to operation in the future.
If a purchaser were to acquire and restart the facility, the State could experience fiscal benefits from tax revenue associated with the sale, potential job creation, and economic activity related to energy production and sales. Because no sale or restart has occurred, these potential benefits cannot be reliably quantified at this time.
F. Compliance costs for affected persons:
The impacted entities will incur no additional costs to comply with these revisions.
For IPP, the new emission limit is not expected to restrict production or facility utilization.
For US Magnesium, the revisions only modify the compliance timeline for previously required controls and do not impose any new control requirements or associated costs.
6. Regulatory Impact Summary Table
Enter the cost or savings in the relevant cell. If there is no cost or savings, enter, "$0." If a cost or savings is inestimable, enter, "inestimable."
7. Regulatory Impact Analysis Approval
The Commissioner of the Department of Environmental Quality, Tim Davis, has reviewed and approved this regulatory impact analysis.
8. Family Impact Information
A. The agency has considered this rule's impact on family health, stability, and formation:
9. Citation Information
Provide citations to the statutory authority for the rule. If there is also a federal requirement for the rule, provide a citation to that requirement:
10. Incorporation by Reference Information Incorporation by Reference (if this rule incorporates more than two items by reference, please include additional tables): A. This rule adds or updates the following title of material incorporated by reference (a copy of the material incorporated by reference must be submitted to the Office of Administrative Rules. If none, leave blank):
Official Title of Materials Incorporated (from title page)
Utah State Implementation Plan, Section XX, Regional Haze.
Division of Air Quality, Utah Department of Environmental Quality
B. This rule adds or updates the following title of material incorporated by reference (a copy of the material incorporated by reference must be submitted to the Office of Administrative Rules. If none, leave blank):
Official Title of Materials Incorporated (from title page)
Utah State Implementation Plan, Section IX, Control Measures for Area and Point Sources, Part H, Emission Limits and Operating Practices.
Division of Air Quality, Utah Department of Environmental Quality
11. Public Notice Information
The public may submit written or oral comments to the agency identified in box 1.
A. Comments will be accepted until:
B. A public hearing (optional) will be held (The public may request a hearing by submitting a written request to the agency, as outlined in Section 63G-3-302 and Rule R15-1.):
Place (physical address or URL):
A public hearing is set for 09/24/2026.
Further details may be found below.
The hearing will be cancelled should no request for one be made by 09/22/ at 10 AM MT.
The final status of the public hearing will be posted on 09/22/2026 after 10 AM MT.
The status of the public hearing may be checked at the following website location under the corresponding rule:
https://deq.utah.gov/public-notices-archive/air-quality-rule-plan-changes-open-public-comment
Interested Persons can participate in person or electronically, via the internet.
In Person:
MASOB
195 N 1950 W, Salt Lake City, UT
First Floor, Air Quality Board Room
Virtual Attendance:
Time zone: America/Denver
Google Meet joining info:
Video call link:
https://meet.google.com/qpx-feyv-vom
Or dial:(US) +1 740-936-3821
PIN: 799 848 699#
12. Effective Date Information
This rule change MAY become effective on:
(NOTE: This is the date the agency anticipates making the filing effective. It is NOT the effective date)
13. Agency Authorization Information
Agency head or
designee and title:
Bryce C. Bird, Director, Division of Air
Quality
R307. Environmental Quality, Air Quality.
R307-110. General Requirements: State Implementation Plan.
R307-110-17. Section IX, Control Measures for Area and Point Sources, Part H, Emission Limits.
The Utah State Implementation Plan, Section IX, Control Measures for Area and Point Sources, Part H, Emission Limits and Operating Practices, as most recently amended by the Utah Air Quality Board on November 4, 2026[July 1, 2026], pursuant to Section 19-2-104, is incorporated by reference and made a part of Rule R307-110. R307-110-28. Regional Haze.
The Utah State Implementation Plan, Section XX, Regional Haze, as most recently amended by the Utah Air Quality Board on November 4, 2026[July 6, 2022], pursuant to Section 19-2-104, is incorporated by reference and made a part of [these rules]Rule R307-110. KEY: air pollution, PM10, PM2.5, ozone
Date of Last Change: [July 1, 2026]2026 Notice of Continuation: December 1, 2021
Authorizing, and Implemented or Interpreted Law: 19-2-104
!--dar--
