The effort grew out of a 2005 deal with the livestock industry, the Air Consent Agreement, which shielded thousands of farms from legal action under the Clean Air Act in exchange for their participation in an industry-funded monitoring study.
The agency said the data from that study are too old and too limited to support methods farms could rely on, and noted that many farms have since modernized their barns and manure systems.
These facilities emit fine particulate matter, ammonia, nitrogen oxides, sulfur dioxide, and volatile organic compounds, and research has linked emissions from them to nearly 12,700 US deaths a year.
The EPA never produced the emissions estimating methods the agreement was meant to deliver, which a 2017 report from its Office of Inspector General criticized as slow-walking.
Tarah Heinzen, legal director of Food & Water Watch, said the agency has been dismantling its own regulatory tools while claiming to pursue the plan, and that it now has no intention of holding factory farms accountable.
The National Pork Producers Council, which long pushed for the decision, said it confirms that every farm is different and no single model fits all.
Heinzen said the law still requires permits for facilities that exceed emissions thresholds, and that the amnesty ends now that the agreement has concluded. She argued that the lack of an EPA methodology does not excuse farms from complying with federal law, pointing to existing studies and to California, which uses its own livestock emissions models to enforce state rules. Still, she expects little measurement or enforcement under this administration. The Trump administration and Congress have also weakened requirements for farms to report air pollutants under the Superfund law (CERCLA) and the Emergency Planning and Community Right-to-Know Act. The agreement never covered methane, and Congress effectively blocks livestock facilities from reporting those emissions through annual spending bills, even though the US livestock industry is the country's largest methane source.