The Trump administration is being sued following the EPA re-approval of the broad-spectrum herbicide trifudimoxazin for use on food crops despite acknowledging the chemical’s potential harms to wildlife and human health.
Food crops include wheat, corn, soybeans oats, apples, oranges, peanuts and almonds among others.
The Center for Food Safety, the Center for Biological Diversity, and Pesticide Action & Agroecology Network North America filed the lawsuit in the 9th Circuit Court of Appeals to overturn the registration based on previous EPA assessments that suggested evidence of carcinogenic potential (such as thyroid tumors in animal studies) and potential severe harm to endangered fish species. Trifludimoxazin is a potent PFAS pesticide that breaks down into longlived, PFAS byproducts. PFAS, or perfluoroalkyl and polyfluoroalkyl substances, are a class of chemicals characterized by ultra-strong carbon-fluorine bonds that are highly resistant to break down and could take decades to break down.
According the science director at the Center for Food Safety, trifludimoxazin is a likely human carcinogen that belongs to a family of weedkillers that also causes reproductive harm, birth defects and neurological deficits in animal studies. The potent herbicide can also drift to stunt crops and wild plants hundreds of yards from a sprayed field, while runoff threatens wetland plants.
Spray drift is likely to result in widespread harm to native plants and crops grown for food. Trifludimoxazin is 10 times more toxic to plants than dicamba, the herbicide whose rampant drift and runoff has caused unprecedent-ed damage across many millions of acres of crops since 2017.
The EPA acknowledges that the chemical causes thyroid tumors in rodent studies but did not assess the cancer risk to farmworkers who use the pesticide or to people exposed to contaminated food or water.
“Continuing to register new herbicides like trifludimoxazin keeps farmers on the pesticide treadmill and perpetuates the problem of herbicide resistance in weeds,” said Emily Marquez, Ph.D., staff scientist with Petitioner Pesticide Action & Agroecology Network North America. “The potential for PFAS pesticides to contaminate water and soil wherever they are used is highly concerning for the health and livelihoods of people in farming communities.”
Even though animal research demonstrates these “PPO inhibitors” have common adverse effects on the liver and cause birth defects in fetuses exposed in utero, the EPA has refused to conduct a cumulative risk assessment of trifludimoxazin and other PPO inhibitors as required by law. A lawsuit in 2021was filed regarding the chemical’s original approval which said violated the federal Insecticide, Fungicide, and Rodenticide Act and the Endangered Species Act. That lawsuit noted the EPA’s finding that the herbicide had the potential to cause cancer and kill fish that were exposed. In response to the lawsuit, the pesticide company voluntarily agreed to stop the manufacture and sale of the pesticide in 2022.
Despite these harms, Trump’s EPA proposed registering trifludimoxazin again for widespread use in 2025 and issued the approval in June 2026.
Trifludimoxazin is the fifth PFAS pesticide approved under the second Trump administration.