The Environmental Protection Agency will not finalize air emissions estimating methods for animal feeding operations and will move to end a 2005 agreement that enrolled thousands of livestock and poultry farms in a national monitoring study.
EPA announced the decision Friday. About 2,600 animal feeding operations, representing nearly 14,000 farms, joined the 2005 Animal Feeding Operations Consent Agreement and Final Order, known as the 2005 Air Compliance Agreement. EPA said its enforcement office will notify those operations to the extent possible and then terminate the agreement.
Abigale Tardif, acting assistant administrator for EPA's Office of Air and Radiation, said the agency would not stand behind results built on the study's data.
"Good science requires good data, and these data are too old and too limited to support methods that farms could rely on," Tardif said. "We would rather tell farmers that plainly than issue numbers we cannot stand behind."
Why the study stalled
The agreement followed a National Academy of Sciences report that called for better ways to estimate air emissions from confinement livestock and poultry farms. Farms that signed on took part in the National Air Emissions Monitoring Study, which collected data on ammonia, hydrogen sulfide, particulate matter and volatile organic compounds from 2005 to 2007.
EPA used the data to draft emissions methods for each sector. Its Science Advisory Board reviewed earlier drafts in 2013, and EPA released updated drafts for public comment in November 2024. After comments closed in August 2025, the agency found limits in how representative and how old the data were that could not be resolved.
That left a gap between the data and the farms. EPA said the measurements reflect barn designs, herd sizes and manure practices that no longer match how many farms operate. In the two decades since, many participating farms changed hands, closed or modernized barns and manure systems, while operations raising hogs, broilers, laying hens and dairy cows waited to learn what permitting or reporting obligations might follow.
What it means for farms
EPA said the decision does not change how it implements the Clean Air Act. It said it will keep working with USDA, land-grant universities and producers on practical, science-based ways to understand and reduce farm air emissions.
Jeffrey Hall, assistant administrator for EPA's Office of Enforcement and Compliance Assurance, said farmers had lived with the possibility of a framework that would treat farms like industrial facilities.
"With this action, the Trump EPA has advanced the rule of law by resolving the long-obsolete obligations under the 2005 Air Compliance Agreement," Hall said.
Deputy Agriculture Secretary Stephen Vaden thanked EPA for reviewing the science and data and said the framework is no longer applicable.
For feed mills and grain merchandisers, the affected farms are a core customer base. Confinement hog, dairy, broiler and egg operations no longer face the prospect of new emissions-based compliance costs tied to the study.
EPA's next step is notifying the roughly 2,600 participating operations before it formally terminates the agreement. The agency did not give a timeline.
