Analysis of the Final Repeal of the Mercury and Air Toxics Standards Amendments
On February 19, 2026, the U.S. Environmental Protection Agency (EPA) finalized the rule that relieves all facilities of the more stringent filterable particulate matter (PM) emission standard for coal-fired EGUs, the tighter mercury standard for lignite-fired EGUs, and the requirement to use PM Continuous Emissions Monitoring Systems (CEMS). The rule is a repeal of 2024 amendments to the National Emission Standards for Hazardous Air Pollutants: Coal- and Oil-Fired Electric Utility Steam Generating Units (EGUs), also known as the Mercury and Air Toxics Standards (MATS). EPA’s power sector analysis for this final rule uses EPA’s Power Sector Modeling Platform 2025.
Incremental Documentation for the EPA’s Power Sector Modeling Platform 2025
For the power sector analysis of this rule, the EPA relied on EPA’s Power Sector Modeling Platform 2025. The links below provide information regarding the reference case used. Additional detail regarding analysis of the final rule is provided in the documentation supplement linked below.
- EPA 2025 Reference Case Incremental Documentation (pdf)
- NEEDS for EPA 2025 Reference Case: rev: 11-28-2025 (xlsx)
- EPA’s Power Sector Modeling Platform 2023
IPM Run Files
Download IPM run files for the final repeal of the 2024 MATS RTR using the links in the table below. Click on the IPM run name in the first column of the table below to download a file. The files are posted in one of two formats, a zipped archive or an excel spreadsheet, and contain detailed IPM input and output files (i.e., DAT, System Summary Report, RPE, and RPT files) for the listed runs. Review the Guide to IPM Input/Output Files (pdf) .
More detailed information on the modeling framework, specific scenarios, assumptions, and other important details of the analysis can be found in the Regulatory Impact Analysis that accompanies the final rule.
| IPM Run Name | IPM Run Description |
|---|---|
| 2025 Reference Case (zip) | The baseline for this final rule includes OBBBA of 2025, and accounts for projected increases in electricity demand stemming from data centers and artificial intelligence applications. It also includes key fleet updates. This does not include the 2024 MATS RTR. |
| 2025 Reference Case with 2024 MATS RTR (zip) | This scenario includes the 2024 filterable PM standard for existing coal-fired EGUs of 0.010 lb/MMBtu and the 2024 mercury standard for lignite-fired EGUs of 1.2 lb/TBtu. |