Atrazine is one of the most widely used herbicides in the United States, second only to glyphosate. Farmers primarily use it to control pre- and post-emergence broadleaf and grassy weeds in crops such as corn, sorghum, and sugarcane.
But atrazine has faced growing scrutiny. The European Union declined to renew atrazine’s approval in 2004, citing the potential for groundwater contamination. Dozens of countries have moved to ban or restrict atrazine. In November 2025, the International Agency for Research on Cancer (IARC) classified atrazine as "probably carcinogenic to humans" (Group 2A). That classification was based on evidence involving non-Hodgkin lymphoma, animal studies, and laboratory research, not prostate cancer.
While the herbicide remains in use in the U.S., in recent years, researchers have studied whether heavy atrazine use is associated with aggressive prostate cancer. In this blog, the attorneys at Wisner Baum discuss the science underpinning allegations in atrazine lawsuits, specifically what the research has found regarding atrazine exposure and aggressive prostate cancer.
Atrazine and Aggressive Prostate Cancer
Decades of research have explored whether atrazine exposure may be associated with aggressive prostate cancer, particularly in younger applicators. Farmers, pesticide applicators, and other agricultural workers typically have the heaviest exposure, and most of the research below focuses on them.
Agricultural Health Study Findings
Launched in 1993, the Agricultural Health Study (AHS) is a long-term prospective study of licensed pesticide applicators and their spouses. It is funded by the National Cancer Institute and the National Institute of Environmental Health Sciences, in collaboration with the Environmental Protection Agency (EPA). Researchers often rely on the AHS to understand potential health outcomes affecting farmers and agricultural workers.
More than 89,000 applicators and spouses in Iowa and North Carolina enrolled in the study.
In February 2024, researchers with the National Cancer Institute published an updated analysis of the Agricultural Health Study in Environmental Health Perspectives. The study, titled “An Updated Evaluation of Atrazine-Cancer Incidence Associations among Pesticide Applicators in the Agricultural Health Study Cohort,” reported that among participants younger than 60, atrazine use was associated with aggressive prostate cancer, which the authors defined as a Gleason score of 8 or higher, a stage 3 diagnosis, or death from prostate cancer.
Participants who had ever used atrazine had roughly double the risk of those who never used it (RR 2.00; 95% CI: 1.18–3.39), and the risk rose with cumulative use, reaching RR 3.04 (95% CI: 1.61–5.75) among those with the most days of use. The authors wrote that the association “is supported by evidence of the role of endocrine disruption in contributing to prostate cancer risk” and that their findings “highlight the potential vulnerability among younger atrazine applicators as a high-risk group.” They also noted that other studies of atrazine and prostate cancer reported mixed results.
How Atrazine May Affect the Prostate
Researchers have studied atrazine as an endocrine disruptor, meaning a chemical that can interfere with the body’s hormone systems. Laboratory studies have reported that atrazine can increase the activity of aromatase, the enzyme that converts testosterone to estrogen, and hormone signaling is known to play a role in prostate cancer. The AHS authors pointed to this endocrine-disruption research as support for the association they observed. These findings come largely from laboratory and animal research; they do not by themselves show how atrazine affects any individual.
Talk to an Atrazine Cancer Lawyer
If you or a loved one were diagnosed with aggressive prostate cancer after years of working with atrazine, you may have legal options. Wisner Baum’s toxic tort attorneys are investigating atrazine claims and offer free, confidential case evaluations to people exposed through farming, pesticide application, groundskeeping, or other work with herbicides.
Wisner Baum has litigated pesticide cancer cases for years, including serving as trial counsel in the Roundup litigation against Monsanto. Managing partner R. Brent Wisner served as co-lead trial counsel in cases that resulted in a $289 million verdict and a $2.055 billion verdict, both later reduced. Those trials were among the first Roundup cases before Bayer announced a settlement program of roughly $11 billion.
Call (310) 207-3233 or fill out our online form to speak with our legal team about a potential atrazine lawsuit.
