LINCOLN, Neb. (DTN) -- An attempt by several environmental groups to push the U.S. Environmental Protection Agency to tighten regulations on concentrated animal feeding operations, or CAFOs, has ended as a federal appeals court denied a petition.

In February 2024, groups led by Food and Water Watch and the Center for Biological Diversity sued EPA for rejecting a 2017 petition to tighten regulations on CAFOs, asked the U.S. Court of Appeals for the Ninth Circuit to review EPA's rejection of that petition.

The Ninth Circuit rejected that petition saying in its ruling, "We may set aside EPA's denial if it was 'arbitrary, capricious, an abuse of discretion, or otherwise not in accordance with law.' Because we find that the EPA did not act arbitrarily, capriciously, or contrary to law, we deny the petition."

The environmental groups argued in a court brief last year that the agency has the authority to revise its interpretation of the agricultural stormwater exemption, calling the agency's decision to reject the petition wholesale "arbitrary and capricious."

Agriculture groups filed a brief in the Ninth Circuit as intervenors in the lawsuit on June 7, 2024. Those groups include National Pork Producers Council, American Farm Bureau Federation, U.S. Poultry and Egg Association and United Egg Producers.

"Although EPA declined to open a rulemaking at this moment, it did not refuse to take any action with respect to its CAFO regulations," the court said in its ruling.

"In response to the petition, EPA acknowledged the serious problem of CAFO-based waste discharges into U.S. waterways and it decided that the most effective way to counter the problem is to further study its effluent limitation guidelines and to commission a stakeholders' subcommittee."

The environmental groups proposed two ways for the EPA to update the CAFO program, including rewriting the rules to require more CAFOs to obtain permits, even if they don't actually discharge pollutants, and to reinterpret the statutory definition of point-source pollution to prohibit the agricultural-stormwater exemption for CAFOs.

Although current CAFO regulations limit land applications of manure, the environmental groups said in a court brief that the rules "exempt a large swath of land application-related discharges from regulation as 'agricultural stormwater.'"

The environmental groups told the court EPA has "consistently failed" to improve CAFO rules.

Agriculture groups that filed briefs in defense of the EPA, said the lawsuit mischaracterized EPA's permitting power and how the system limits pollution from CAFOs.

They said many states impose more requirements on livestock operations than the federal program. The ag groups argued all CAFOs "whether permitted or unpermitted" must meet a zero-discharge standard.

Ag groups said precipitation runoff from land-application areas are excluded from permitting "only if CAFO farmers apply manure, litter, or process wastewater" using "sound" agricultural practices.

EPA regulations previously required CAFOs to apply for National Pollution Discharge Elimination System, or NPDES, permits if they planned to discharge pollutants.

In 2011, however, the U.S. Court of Appeals for the Fifth Circuit vacated the requirement.

In 2023, EPA announced the launch of a study of pollution generated by CAFOs after rejecting petitions from environmental groups from 2017 and 2022.

The 2022 petition was filed by numerous state-level clean water advocacy groups as well as Friends of the Earth, Earthjustice, Humane Society of the United States and others. It asked EPA to adopt a presumption that large CAFOs using wet manure management systems discharge pollutants.

The 2017 petition asked the EPA to change CAFO regulations to assume several things, including that CAFOs with certain production-area characteristics do actually discharge; regulations should assume CAFOs applying manure to land as fertilizer actually discharge; to revise the EPA interpretation of the agricultural stormwater exemption to clarify that it does not include any CAFO-related discharges, among other requests.

Read more on DTN:

"Ag Groups Defend EPA in Ninth Circuit," https://www.dtnpf.com/….

"Groups Say CAFO Regulations Needed," https://www.dtnpf.com/….

Todd Neeley can be reached at todd.neeley@dtn.com

Follow him on social platform X @DTNeeley

(c) Copyright 2025 DTN, LLC. All rights reserved.