EPA approves forever chemical herbicide its own review calls a likely carcinogen

Three environmental and food safety groups sued the Trump administration on Friday over the Environmental Protection Agency’s approval of a new pesticide, trifludimoxazin, that the agency’s own review found is a likely human carcinogen and belongs to the “forever chemical” class of compounds that do not break down in the environment, according to a press release from the Center for Biological Diversity.

The Center for Food Safety, the Center for Biological Diversity and the Pesticide Action & Agroecology Network North America filed the lawsuit on August 28 in the US Court of Appeals for the 9th Circuit, arguing the EPA’s approval violated the Federal Insecticide, Fungicide, and Rodenticide Act and the Endangered Species Act. Trifludimoxazin is a contact herbicide classified as a Group 14, or PPO-inhibiting, chemical by the Herbicide Resistance Action Committee and the Weed Science Society of America, industry bodies that track how weeds develop resistance to different chemical classes.

Trifludimoxazin is a per- and polyfluoroalkyl substance, or PFAS, a class of synthetic chemicals known to persist in soil and water for years to decades. It is the fifth PFAS pesticide approved under the second Trump administration, according to the Center for Biological Diversity. The EPA disputes that classification, saying the chemical does not meet the definition of PFAS the agency adopted under the Biden administration.

The herbicide, sold by manufacturer BASF under the brand name Tirexor, was first approved by the EPA in 2021 for use on corn, soy, fruit and nut crops nationwide. BASF voluntarily withdrew those registrations in 2022 after the agency was sued over the approval. The EPA’s June 2026 decision covers one technical product and five end-use products, according to the EPA’s own announcement, and applies to corn, wheat, oats, soybeans, oranges, apples, peanuts and almonds.

Bill Freese of the Center for Food Safety said in the press release, “Trifludimoxazin is a likely human carcinogen that belongs to a family of weedkillers that also causes reproductive harm, birth defects and neurological deficits.” Nathan Donley of the Center for Biological Diversity said, “It’s unconscionable, immoral and illegal. Our kids and grandkids deserve better than to be saddled with pollution that never goes away.” Emily Marquez of the Pesticide Action & Agroecology Network North America said, “The potential for PFAS pesticides to contaminate water and soil wherever they are used is highly concerning.”

The lawsuit cites the EPA’s own finding that the herbicide is roughly ten times more toxic to plants than dicamba, another herbicide whose drift has damaged millions of acres of neighboring crops since it was approved for similar use in 2017. The suit also cites EPA data showing trifludimoxazin causes thyroid tumors in rodents at high doses.

The plaintiffs argue the chemical is also likely to severely harm threatened and endangered fish species, including Chinook salmon, steelhead trout, Atlantic sturgeon and smalltooth sawfish, based on the EPA’s own risk assessment. The suit asks the court to vacate the agency’s approval.

The case is pending before the 9th Circuit. The EPA had not filed a public response to the lawsuit as of the Center for Biological Diversity’s August 31 release.