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The number of large concentrated animal feeding operations (CAFOs) in Iowa has increased 13% over the past six years, according to a new report. The problem is growing in the state, which generates more than 100 million tons of fertilizer each year, contributing to persistent water pollution and health problems.
The report is mapping project According to a study by the Environmental Working Group (EWG), Iowa has approximately 15,309 livestock farms that generate 107 million tons of fertilizer each year, but more than a quarter of the farms are not monitored by the state. Widely cited fertilizer estimates from Iowa’s largest farms are: 2022 USDA data The total is estimated at 55 million tons per year. But Anne Schechinger, EWG’s senior director of agriculture and climate research and a co-author of the analysis, said EWG’s estimates include not only fertilizer on small farms, but also on farms that have increased since the previous estimate.
Schechinger believes the report’s findings are important because Iowa has struggled with water quality issues and a disproportionately high cancer rate, the second-highest in the nation.
Credit: EWG, data provided by USDA National Agricultural Imagery Program and Iowa DNR
“We know that nitrogen is in fertilizers. Iowa has a serious problem with nitrates in drinking water, and nitrates increase the risk of cancer,” she says.
Using aerial and satellite data to plan facilities, Schechinger and his colleague Ethan Barhe, a senior GIS analyst at EWG, also found that the largest CAFO farms (farms with 1,000 or more animal units) increased from 3,936 farms to 4,444 farms from 2019 to 2025. Animal units are used by regulatory authorities to convert animals to equivalent units. 1,000 animal units equals 1,000 beef cattle, while for pigs, 2,500 animals equals 1,000 animal units.
These CAFOs are mostly hog farms, accounting for 29% of Iowa’s livestock production but 60% of its fertilizer production.
Chris Jones, a Democrat running for Iowa Secretary of Agriculture, said he was somewhat surprised to see how much the number of hog CAFOs has increased over the past few years, especially as there is increasingly “additional concern and frustration” about contamination from large farms.
“There are people in agriculture who agree with that, and there are people in Republican politics who agree with that,” said Jones, an author and former University of Iowa researcher. Jones has spent much of his career monitoring and researching the state’s water quality.
“People really feel that this system that we have in place with respect to CAFOs is not producing outcomes that are beneficial to everyone,” he said.
Pollution and cancer incidence
The report comes as levels of nitrates, a cancer-causing byproduct of fertilizers and some fertilizers discharged or runoff into rivers and streams, continue to rise in some of the state’s waterways. a Separate EWG report In April, 146 community water systems in Iowa were found to have elevated nitrate levels at least once between 2021 and 2023. Iowa’s Des Moines and Raccoon rivers are in the top 1% of the nation’s rivers for nitrates, and 80% of the pollution comes from agriculture.
Just last month, the Central Iowa Water District (CIWW) implemented water restrictions for hundreds of thousands of customers after the water utility was unable to keep up with rising nitrate levels in the water.
“The situation has reached a point where mandatory conservation is necessary to protect reliable water service for more than 600,000 people across central Iowa,” said CIWW Executive Director Tami Madsen. in a statement.
Iowa’s Raccoon River ranks in the top 1% of nitrate concentrations of rivers in the nation. (Credit: Christine Warner-Morin/flickr)
Additionally, Iowa continues to struggle with rising cancer rates that are caused, at least in part, by nitrates from CAFOs. According to researchers. Iowa has the second highest cancer rate in the nation. Only 1 of 3 states with cancer on the riseaccording to the National Institutes of Health.
For many types of cancer, the state’s numbers are well below the national average. For example, the prostate cancer incidence rate in Iowa is 129 per 100,000 people, while the U.S. average is 116 per 100,000. The state’s breast cancer incidence rate is 137 per 100,000 people, compared to the national average breast cancer rate of 131. The state’s overall cancer rate is 498 per 100,000 people, which is 10% higher than the national cancer rate.
“The fact that phosphorous from fertilizers is causing algae blooms and negatively impacting recreation is an issue that contributes to Iowa’s status as a high cancer risk state,” Schechinger said.
Some experts say there is a clear disconnect between the public’s concerns about Iowa’s rising cancer rates and the actions of state policymakers. “That concern clearly hasn’t been reflected in state governments or regulators,” said Sylvia Secchi, a researcher and professor at the University of Iowa who studies the environmental impacts of agriculture.
“These aren’t outsiders or environmentalists looking for answers about CAFOs. These are people who live there and can’t open their windows… who are seeing their property values go down because they’re next to these businesses,” she said. “They are members of a community who are suffering and are not being given the protections they deserve.”
county level supervision
EWG’s analysis found that 3,276 livestock operations in Iowa have between 950 and 999 animal units, which is slightly below the 1,000 animal unit standard that requires a National Pollutant Discharge Elimination System (NPDES) federal water permit and manure management plan.
“Some of these facilities are very close to each other, and that proximity is very important in terms of water quality,” Bahe said. “If you have two facilities that approach the large-scale (1,000 animal unit) designation but are considered separate facilities, an NPDES permit is not required.”
NPDES permits are issued by state regulators, and each state has different CAFO NPDES permits. According to , Iowa has issued NPDES permits for about 4% of large CAFO facilities. federal estimate.
For decades, researchers and advocates have argued that Iowa regulators vastly underestimate and under-regulate CAFOs, Secchi explained. The state entered into an agreement with the U.S. Environmental Protection Agency (EPA) in 2013 that requires the state Department of Natural Resources, which regulates CAFO pollution, to conduct a statewide survey of CAFOs. In 2017, Status reported The satellite images showed an additional 5,000 previously undetected and unregulated activities.
“This new report shows that they still haven’t learned any lessons,” Secchi said. “This is why there are so many CAFOs in Iowa, because the DNR is not doing its job.”
“This new report shows they haven’t learned any lessons yet. This is why there are so many CAFOs in Iowa. It’s because the DNR isn’t doing its job.” – Sylvia Secchi, University of Iowa
The Iowa DNR did not respond to requests for comment regarding CAFO regulations and permits.
Jones said this lax enforcement is not “deliberate inaction” by the DNR, but rather likely “simply not enough resources within the DNR to effectively go after these facilities.”
Schechinger said one policy to address this is for Iowa to move decision-making and regulation of CAFOs and other livestock farms to the county level.
“Currently, facilities with 500 or more animals in the state are required to have a manure management plan, but the Iowa DNR has performed very few tests on these facilities,” she said. “If this regulation were applied to counties, it would actually result in more inspections, more checks on fertilizer management plans, and more enforcement.”
“This is one of the ideas that I think has bipartisan support and has the potential to make a big difference on water quality issues,” she added.
Jones agreed. “We absolutely need the county to have zoning authority for these facilities for new construction and some authority for expansion of existing facilities,” he said.
Featured image credit: Getty Images/Unsplash +
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Brian Bienkowski is the editor-in-chief of The New Lede. He is a veteran journalist with over 15 years of experience covering the environment and human health. Prior to joining TNL, he was a senior editor at Environmental Health News for nearly a decade, overseeing the newsroom and two local bureaus. He was also the founder, producer, and host of the EJ podcast Agents of Change from 2020 to 2024.
Bienkowski has received multiple awards for her editing and reporting, including honors from the Healthcare Journalists Association, Columbia School of Journalism, Hunter College, and the Environmental Journalists Association. He has a master’s degree in environmental journalism from Michigan State University and lives in northern Michigan.
