Illegal Manure Pollution in Water — and Cancer — on the Rise in Iowa

A new report from environmental watchdog group Food & Water Watch suggests that almost 2 million fish were killed from manure spills in Iowa between 2013 and 2023. The 179 spills occurred throughout the state, with a major hotspot for spills in the northwest corner of the state. Earlier this year, the group reported that Iowa factory farms produce more waste than any other state, at 109 billion pounds of manure annually, based on U.S. Department of Agriculture data.

The report and accompanying map, released on Dec. 9, designated over 700 segments of Iowa water as “impaired” — not meeting the standards necessary to support aquatic life, public water supplies or recreation. Details include where in the state spills occur, who owns the operation and if they are repeat offenders.

Manure spills in the state of Iowa have contributed to what environmental advocacy groups call a water quality crisis. In the capital city of Des Moines, the local water supply has one of the world’s largest nitrate removal facilities. Nitrate is the resulting chemical of manure that is not absorbed by the soil or crops. Due to high levels of nitrate in water, which can cause blue baby syndrome in children and colon cancer in adults, the Des Moines Water Works has to run its nitrate removal system more frequently as the situation worsens — at a cost of anywhere from $10,000 to $16,000 per day, which falls entirely on utility customers.

“When you think about the nature of what they’re spilling and the quantities of what they’re spilling, it’s the difference between life and death, and people are being strapped down with medical debt and suffering in a prolonged way,” Food & Water Watch Iowa Organizer Michaelyn Mankel tells Sentient.

According to the report, the Iowa Department of Natural Resources fined 171 of the 179 offenders at $635,808 over the ten-year period it studied. That’s less than half of what Des Moines Water Works spent on its nitrate removal system in 2015, at $1.4 million. There are gaps in the state reporting as well. The total volume of the spills is difficult to determine because most reports do not contain information on how much manure is spilled. And in those that do note volume, the range is anywhere from 500 to 1 million gallons.

“The fines that the DNR has leveled against these companies do not represent restitution for the damage that they’re causing to Iowa,” Mankel says. “They also don’t represent a real demand that these corporations change the way that they’re doing business.”

In 2024 alone, the Iowa Department of Natural Resources documented 13 fish kill events, one of which regulators directly tied to animal waste. This one “anthropogenic” spill in northwest Iowa — caused by dairy manure land-applied runoff —killed anywhere from 100,001-500,000 fish.

Many concentrated animal feeding operations operate without the proper discharge permits, rendering their spills more difficult to track. In October, the Ninth Circuit Court of Appeals struck down a petition from 13 groups — including Food & Water Watch — calling for stricter regulation and enforcement of the Clean Water Act. Today, Food & Water Watch is calling for a “Clean Water for Iowa Act” to be passed in the state legislature. The act would require all medium and large-scale concentrated animal feeding operations to get National Pollutant Discharge Elimination System permits.

This report and map are released in the midst of a health crisis in the Midwest, which some observers and critics argue is tied to, or exacerbated by, large-scale industrialized agriculture. Mankel points to cancer incidence in the state of Iowa; it’s the only state in the country with rising cancer rates(though other factors, like obesity and alcoholism rates may play a role).

“We’re paying for it,” Mankel says. “I really want Iowans to understand that these problems are a policy choice, and that we are being burdened with paying the true cost of massive profits that these corporations are reaping from our state, and that’s a very intentional choice on behalf of lawmakers.”