MINNEAPOLIS – Huge amounts of manure from massive livestock facilities in Minnesota could pollute drinking and recreational water throughout the state, posing a significant health risk.
That’s the conclusion of a new Environmental Working Group report that updates a similar analysis from 2020, which found widespread risk for water contamination from livestock operations in the state. In 2024, cattle, hog and poultry production at 23,503 facilities produced almost 49 million tons of manure, the new analysis finds. The waste they generate is equivalent to almost 8.5 tons of manure yearly for every Minnesotan.
The enormous quantities of manure these facilities generate are often applied to nearby farm fields as a fertilizer, since the nitrogen and phosphorus it contains are nutrients that feed crops.
But manure and its components can wash off farm fields, leach through soil into drainage systems that empty into nearby streams, and get into groundwater. This contamination pollutes tap water served to homes across Minnesota and fouls recreational water.
“The combination of commercial fertilizer and manure from Minnesota’s livestock production is overloading crop fields, creating a public health risk,” said EWG Senior GIS Analyst and report author Ethan Bahe.
“This excessive amount could eventually end up in Minnesotans’ tap water or the recreational waters that are so important to the state,” he said.
A problem for years
This year’s report found only a negligible decrease in the amount of manure and number of facilities from the earlier report. Five years later, EWG’s updated analysis shows livestock production and manure have become more concentrated at the largest cattle facilities, which increased in number by over 12 percent.
EWG’s updated study used a set of GIS tools to model manure application from those 23,503 facilities to the crop fields closest to the facilities. Fields were assessed for the nitrogen needs for the crops that grow there over a six-year period.
“This report gives a clear picture of continued consolidation in the Minnesota livestock industry, and a large number of feedlots just below permit thresholds in the state,” said Carly Griffith, water program director at the Minnesota Center for Environmental Advocacy.
“Its release comes at a critical time, as Minnesota prepares to revise the state feedlot rule,” she added.
The rule applies to all feedlots in the state and includes requirements for permits, the land application of manure, design and construction standards, and more. The rule was last revised significantly in 2000, and the livestock industry has changed appreciably since then.
The Minnesota Pollution Control Agency currently has a public comment period open as it considers revising the state’s feedlot rule. The revision would improve practices used to apply manure to the land as a way to address nitrate contamination and fish kills, among other issues.
“It’s not surprising that the sheer amount of manure generated and the large number of livestock facilities haven’t changed much since EWG last assessed the situation five years ago,” Bahe added. “This is a serious problem long overdue for a solution.”
Threat to drinking water
Nitrogen from manure can form in drinking water as nitrate, and consuming water contaminated with it can increase the risk of birth defects and cancer.
Manure runoff can also create potentially toxic algae blooms in recreational waters when manure is applied in quantities that exceed what crop fields can handle. EWG has previously reported on toxic algae blooms in bodies of water throughout Minnesota.
“These factory farms produce much more manure than nearby crop fields can handle, which leads to manure pollutants frequently getting into water. This threatens drinking water for people across the state and also harms the recreational waters that so many of us Minnesotans cherish,” said Anne Schechinger, EWG’s Midwest director.
“State and federal policymakers need to step up their oversight of factory farms and pursue strategies that can do a significantly better job of tackling this pollution,” she added.
Changes at the federal and state level could help tackle the manure overload problem. At the federal level, much less conservation funding should go to structural practices for animal feeding operations. These practices include waste storage facilities and covers for manure pits, both of which encourage more production and waste.
At the state level, Minnesota could more strictly regulate animal feeding operations to reduce the risk of animal manure polluting water. One option is regulating facilities that fall below the Environmental Protection Agency’s threshold for requiring Clean Water Act discharge permits. The threshold currently exempts a large number of livestock facilities.
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The Environmental Working Group (EWG) is a nonprofit, non-partisan organization that empowers people to live healthier lives in a healthier environment. Through research, advocacy and unique education tools, EWG drives consumer choice and civic action.
