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Environmental Protection Agency

National Emission Standards for Hazardous Air Pollutants: Coal- and Oil-Fired Electric Utility Steam Generating Units: Final Repeal

Published February 24, 2026. Takes effect April 27, 2026, printed at 91 FR 9088, amending 40 CFR 63. 37,051 words.

In plain English

This repeals some air pollution limits that had been added.

Read it at the Federal Register →

What the Rule Says It Does

The U.S. Environmental Protection Agency (EPA) is finalizing the repeal of specific amendments to the National Emission Standards for Hazardous Air Pollutants (NESHAP) for Coal- and Oil-Fired Electric Utility Steam Generating Units (EGUs), commonly referred to as the Mercury and Air Toxics Standards (MATS), that were promulgated on May 7, 2024. Specifically, the EPA is repealing the revised filterable particulate matter (fPM) emission standard, which serves as a surrogate for non-mercury hazardous air pollutant (HAP) metals for existing coal- fired EGUs; the revised fPM emission standard compliance demonstration requirements; and the revised mercury (Hg) emission standard for lignite-fired EGUs. The EPA is also making technical, non-substantive clarifications to electronic reporting requirements.

This is the rule's own summary, as the Federal Register prints it.

The Orders It Names

The rule names these orders itself. What it does about them is a reading, and none is recorded here.

On the Face of the Rule

As filed

[Federal Register Volume 91, Number 36 (Tuesday, February 24, 2026)] [Rules and Regulations] [Pages 9088-9134] From the Federal Register Online via the Government Publishing Office [www.gpo.gov] [FR Doc No: 2026-03638]

Vol. 91

Tuesday,

No. 36

February 24, 2026

Part IV

Environmental Protection Agency

40 CFR Part 63

National Emission Standards for Hazardous Air Pollutants: Coal- and Oil-Fired Electric Utility Steam Generating Units: Final Repeal; Final Rule

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 63

[EPA-HQ-OAR-2018-0794; FRL-6716.4-02-OAR] RIN 2060-AW68

National Emission Standards for Hazardous Air Pollutants: Coal- and Oil-Fired Electric Utility Steam Generating Units: Final Repeal

AGENCY

Environmental Protection Agency (EPA).

ACTION

Final rule.

DATES

The final rule is effective on April 27, 2026. The Director of the Federal Register (FR) approved incorporation by reference (IBR) of certain publications listed in the rule on April 16, 2012 and May 30, 2023.

ADDRESSES

The EPA established a docket for this action under Docket ID No. EPA-HQ-OAR-2018-0794. All documents in the docket are available on the https://www.regulations.gov website. Although listed, some information is not publicly available, e.g., Confidential Business Information or other information whose disclosure is restricted by statute. The EPA does not place certain other material, such as copyrighted material, on the internet; this material is publicly available only as Portable Document Format (PDF) versions and accessible only on EPA computers in the docket office reading room. The public cannot download certain databases and physical items from the docket but may request these items by contacting the docket office by telephone at (202) 566-1744. The docket office has 10 business days to respond to such requests. Except for these items, publicly available docket materials are available electronically at https://www.regulations.gov or on the EPA computers in the docket office reading room at the EPA Docket Center, WJC West Building, Room Number 3334, 1301 Constitution Ave. NW, Washington, DC. The Public Reading Room hours of operation are 8:30 a.m. to 4:30 p.m. Eastern Time (ET), Monday through Friday. The telephone number for the Public Reading Room is (202) 566-1744, and the telephone number for the EPA Docket Center is (202) 566-1742.

FOR FURTHER INFORMATION CONTACT

For information about this final rule, contact Christopher Werner, Industrial Processing and Power Division (IPPD) (D243-01), Office of Clean Air Programs (OCAP), U.S. Environmental Protection Agency, P.O. Box 12055, Research Triangle Park, North Carolina 27711; telephone number: (919) 541-5133; and email address: [email protected]. Individuals who are deaf or hard of hearing, as well as individuals who have speech or communication disabilities, may use a telecommunications relay service. To learn more about how to make an accessible telephone call to any of the telephone numbers shown in this preamble, please visit the web page (https://www.fcc.gov/trs) for the relay service of the Federal Communications Commission, and a list of relay services is available on their directory page (https://www.fcc.gov/general/trs-state-and-territories).

The fields the Federal Register prints at the head of the rule, quoted as printed. Its summary is quoted above.

Why the Agency Says It Is Doing This

SUPPLEMENTARY INFORMATION

Preamble acronyms and abbreviations. Throughout this notice the use of “we,” “us,” or “our” refers to the EPA. We use multiple acronyms and terms in this preamble. While this list may not be exhaustive, to ease the reading of this preamble and for reference purposes, the EPA defines the following terms and acronyms here:

ACI activated carbon injection BLDS bag leak detection systems BTF beyond the floor Btu British thermal units CAA Clean Air Act CEMS continuous emission monitoring system(s) CFB circulating fluidized bed CFR Code of Federal Regulations CPMS continuous parametric monitoring system(s) CRA Congressional Review Act EAV equivalent annualized values ECMPS Emissions Collection and Monitoring Plan System EGU electric utility steam generating unit EIA U.S. Energy Information Administration ESP electrostatic precipitator FF fabric filter FGD flue gas desulfurization fPM filterable particulate matter FR Federal Register GACT generally available control technologies GWh gigawatt-hour HAP hazardous air pollutant(s) HCl hydrogen chloride HF hydrogen fluoride Hg mercury HQ hazard quotient ICR Information Collection Request IGCC integrated gasification combined cycle IPPD Industrial Processing and Power Division IRA Inflation Reduction Act lb pounds LEE low emitting EGU MATS Mercury and Air Toxics Standards MMBtu million British thermal units of heat input MW megawatt NAICS North American Industry Classification System NESHAP national emission standards for hazardous air pollutants NTTAA National Technology Transfer and Advancement Act OCAP Office of Clean Air Programs OMB Office of Management and Budget PDF Portable Document Format PM particulate matter PM CEMS particulate matter continuous emission monitoring system(s) PRA Paperwork Reduction Act PV present values REL reference exposure level RFA Regulatory Flexibility Act RIA Regulatory Impact Analysis RIN Regulatory Information Number RTR residual risk and technology review SO2 sulfur dioxide SO3 sulfur trioxide TBtu trillion British thermal units of heat input TOSHI target organ-specific hazard index tpy tons per year UMRA Unfunded Mandates Reform Act XML Extensible Markup Language

The passage that opens the rule's preamble, where the agency sets out what it is doing and on what authority. Every heading that follows it is listed below.

What the Rule Contains

Every heading the Federal Register prints in this rule, in the order it prints them. 45 headings, 37,051 words in all.

  1. AGENCYOn its face · 5 words
  2. ACTIONOn its face · 3 words
  3. SUMMARYOn its face · 112 words
  4. DATESOn its face · 37 words
  5. ADDRESSESOn its face · 207 words
  6. FOR FURTHER INFORMATION CONTACTOn its face · 121 words
  7. SUPPLEMENTARY INFORMATIONPreamble · 311 words
  8. Table of ContentsPreamble · 3 words
  9. I. General InformationPreamble · 333 words
  10. I. General InformationPreamble · 3 words
  11. A. Executive SummaryPreamble · 1,792 words
  12. B. Does this action apply to me?Preamble · 150 words
  13. C. Where can I get a copy of this document and other related information?Preamble · 144 words
  14. D. Judicial Review and Administrative ReconsiderationPreamble · 253 words
  15. II. BackgroundPreamble · 2 words
  16. A. What is the authority for this action?Preamble · 8 words
  17. 1. What is the statutory authority for this action?Preamble · 1,212 words
  18. B. What is the coal- and oil-fired EGU source category, and how does the NESHAP regulate emissions from the source category?Preamble · 427 words
  19. C. Summary of the 2020 Final RulePreamble · 937 words
  20. D. Summary of the 2024 Review of the 2020 Final RulePreamble · 904 words
  21. E. Summary of the 2025 Proposed RepealPreamble · 248 words
  22. III. Basis for Final Repeal of the 2024 Final RulePreamble · 719 words
  23. A. Filterable PM Emission Standard for Existing Coal-Fired EGUsPreamble · 9 words
  24. 1. What is the EPA finalizing for the filterable PM emission standard for existing coal-fired EGUs?Preamble · 7,866 words
  25. B. Required Compliance Demonstration for the Filterable PM StandardPreamble · 9 words
  26. 1. What is the EPA finalizing for the compliance demonstration requirements for the filterable PM standard?Preamble · 5,074 words
  27. C. Hg Emission Standard for Lignite-Fired EGUsPreamble · 7 words
  28. 1. What are we finalizing as the Hg emission standard for lignite-fired EGUs?Preamble · 3,782 words
  29. IV. Comments and Responses on the Relevance of Residual Risk to Technology Reviews Under CAA Section 112(d)(6)Preamble · 467 words
  30. B. What is the EPA finalizing regarding the relevance of residual risk to technology reviews under CAA section 112(d)(6)?Preamble · 1,842 words
  31. V. What is the rationale for other final decisions and amendments from the reevaluation of the 2024 Final Rule?Preamble · 412 words
  32. VI. Statutory and Executive Order ReviewsPreamble · 18 words
  33. A. Executive Order 12866: Regulatory Planning and Review and Executive Order 13563: Improving Regulation and Regulatory ReviewPreamble · 803 words
  34. B. Executive Order 14192: Unleashing Prosperity Through DeregulationPreamble · 44 words
  35. C. Paperwork Reduction Act (PRA)Preamble · 476 words
  36. D. Regulatory Flexibility Act (RFA)Preamble · 248 words
  37. E. Unfunded Mandates Reform Act (UMRA)Preamble · 60 words
  38. F. Executive Order 13132: FederalismPreamble · 46 words
  39. G. Executive Order 13175: Consultation and Coordination With Indian Tribal GovernmentsPreamble · 119 words
  40. H. Executive Order 13045: Protection of Children From Environmental Health Risks and Safety RisksPreamble · 142 words
  41. I. Executive Order 13211: Actions Concerning Regulations That Significantly Affect Energy Supply, Distribution, or UsePreamble · 101 words
  42. J. National Technology Transfer and Advancement Act (NTTAA) and 1 CFR Part 51Preamble · 55 words
  43. K. Congressional Review Act (CRA)Preamble · 46 words
  44. List of Subjects in 40 CFR Part 63Regulatory text · 88 words
  45. Subpart A--General ProvisionsRegulatory text · 7,312 words

The Rest of the Text

This rule runs to 37,051 words. The rest of it is set out over 3 pages, split at the rule's own headings so that no heading is parted from the words printed under it.

How to cite this
  1. The rule itself

    Environmental Protection Agency, “National Emission Standards for Hazardous Air Pollutants: Coal- and Oil-Fired Electric Utility Steam Generating Units: Final Repeal,” 91 FR 9088 (February 24, 2026). Effective April 27, 2026.
    https://www.federalregister.gov/documents/2026/02/24/2026-03638/national-emission-standards-for-hazardous-air-pollutants-coal--and-oil-fired-electric-utility-steam

  2. This page

    “National Emission Standards for Hazardous Air Pollutants: Coal- and Oil-Fired Electric Utility Steam Generating Units: Final Repeal,” a final rule naming an order indexed here. Read the Mandate, https://readthemandate.org/rules/rule-2026-03638/ (retrieved October 10, 2026).

Cite the document when the claim is about what the document says. Cite this page when the indexing, the wording or the record of what has happened is what is being relied on.

How This Rule Is Set Out

Federal Register documents are United States government works and are not under copyright, so the rule is here whole rather than cut to an excerpt. It is split at the headings the Register itself prints: the line it is filed under, the captioned fields on its face, the preamble where the agency says what it is doing and why, and the amendments to the Code of Federal Regulations. No passage is shortened. This rule is long enough that its text is set out over 3 pages rather than one.

Two things the Register prints are not reproduced: the running head it repeats at every page break, and the tables it sets as pictures rather than as words. Its own marker for one of those tables, [GRAPHIC] [TIFF OMITTED], is left standing where the table was, so a reader can see that something is there and follow the link to the page it is on.