LINCOLN, Neb. (DTN) -- The U.S. Environmental Protection Agency dropped efforts to create nationwide air-emissions models for livestock and poultry operations because data is limited and outdated, making it impossible to create credible estimates for animal feeding operations, the agency said at the end of last week.
The EPA announcement on a two-decade-old effort affects about 2,600 animal feeding operations across the country that joined EPA's 2005 air compliance agreement. Those producers funded a national study to determine whether livestock and poultry facilities could trigger air permitting or reporting requirements.
Agriculture groups including the National Pork Producers Council and the National Milk Producers Federation have long held that such modeling could lead to more regulation of farms.
"This move confirms what farmers have long known: Every farm is different, and there is no one-size-fits-all model to apply to them," NPPC president and Iowa farmer Rob Brenneman said in a statement following the EPA announcement.
"Each farm should be judged on its own factors, including its location, its practices, its animals and its people. We're grateful to EPA for listening to the farmers who feed this nation."
The agency said when producers originally volunteered to study potential modeling efforts, the goal was to create tools for farms to estimate their emissions.
"In the over two decades since, many participating farms have changed hands, closed, or modernized their barns and manure systems," the EPA said in a news release.
"Farmers raising hogs, broiler chickens, egg-laying hens and dairy cows have waited that entire time without knowing what new permitting or reporting obligations might follow once the methods were finalized. After evaluating the NAEMS data collected from 2005-2007, EPA concluded that the data are too old and too limited to support reliable methods. The data reflect barn designs, herd sizes, and manure practices that no longer represent how many farms operate today."
EPA said it plans to notify approximately 14,000 farms connected to the 2,600 animal feeding operations before terminating the agreement.
"EPA will continue to work with the U.S. Department of Agriculture, land-grant universities and producers on practical, science-based ways to understand and reduce air emissions from farms and will continue to put farmers first in recognition of the vital role they play in feeding the nation," EPA said last week.
Jeffrey Hall, EPA assistant administrator for the Office of Enforcement and Compliance Assurance, said in a statement that farmers have been "living for two decades with the threat" that at "any moment" EPA could release a new emissions framework that treats farms like "major industrial facilities" required to seek permits.
EPA developed draft emissions estimating methods for each participating sector and the agency's science advisory board reviewed earlier drafts in 2013, according to the agency.
In November 2024, EPA released updated draft methods for public comment. After the comment period closed in August 2025, EPA identified key limitations with respect to the representativeness and age of data, as well as changes to standard operational practices and technologies that "could not be resolved" with the existing data, the agency said.
"Dairy farmers signed up for this study in good faith two decades ago and they've been waiting ever since to find out what it would mean for their farms," said Gregg Doud, president and CEO of NMPF.
"You can't measure a handful of farms years ago and use those numbers to set expectations for thousands of other farms. We appreciate EPA following the data and giving farmers a clear, final answer."
In comments filed with the EPA in 2025, the NMPF told the agency draft dairy emissions models were built on data from just five dairies.
NMPF said its own technical analysis found that the models produced per-cow emission estimates that "swung dramatically" with herd size, "predicted negative emissions in below-freezing weather," and offered "no way to account" for the advances in feed, genetics, manure management and emissions control that dairy farmers have adopted since the data were collected.
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