The EPA recently okayed 10 new insecticides containing isocycloseram, a chemical that critics say hasn’t been adequately tested long-term. Is there cause for concern?
The Environmental Protection Agency (EPA) recently announced that it’s moving forward to permit the use of 10 new pesticide products that contain the insecticide isocycloseram.
Farmers can potentially use the pesticides in numerous ways, including to kill pests on agricultural crops such as potatoes, cruciferous vegetables like broccoli and kale, and citrus.
“No human health risks of concern were identified when isocycloseram is used according to the registered labels,” the EPA noted.
However, many environmental experts and advocates have been loudly critical of this decision because, they say, isocycloseram contains harmful PFAS (per- and polyfluoroalkyl substances). PFAS are called “forever chemicals” because they may never break down naturally in the environment.
EPA Decision Has Stirred Controversy
Alexis Temkin, PhD, vice president of science at the nonprofit Environmental Working Group, calls the move “concerning” because of studies linking PFAS exposure to a number of negative health effects, ranging from decreased fertility to increased risk of some cancers.
The EPA has countered by saying that isocycloseram is not, in fact, a PFAS. The federal government defines PFAS as chemicals containing two or more fluorinated carbons; isocycloseram is a single-fluorinated carbon, chemicals that the EPA says “lack the persistence and bioaccumulation properties that are commonly associated with forever chemicals.”
Isocycloseram is “very different” from traditional PFAS because it does break down in the environment to some extent, says P. Lee Ferguson, PhD, an environmental analytical chemist and professor at the Nicholas School of the Environment at Duke University in Durham, North Carolina, who is not affiliated with the EPA.
But he says the chemical still needs to be studied in more detail to fully understand its health and environmental effects.
Any potential for harm would depend on several factors — including how much and how quickly isocycloseram breaks down — which are factors we don’t know yet, Dr. Ferguson notes.
EPA's Safety Evaluation: What They Tested
In a “fact check” statement that the EPA issued to address what it called “misinformation” about the pesticide approvals, the agency said its evaluation process included:
Comprehensive toxicity studies across multiple species and life stages
Specific evaluation of children's safety and developmental effects
Assessment of reproductive and chronic health impacts
Environmental fate and exposure analysis
None of the experts interviewed for this story knew what these tests involved and declined to comment on their results or validity.
Should You Worry About the New Pesticides?
Debra Cherry, MD, an associate professor of environmental medicine at the University of Washington Harborview Medical Center in Seattle, says that she doesn’t have any immediate concerns about eating fresh produce treated with the new pesticides.
“I am worried, however, about the adverse impact on pollinators like bees, the ecosystem, and vulnerable populations like infants consuming contaminated water in the future,” Dr. Cherry says.
It can be difficult to completely avoid PFAS since they come from a variety of sources, Cherry notes. She recommends rinsing produce before eating to potentially reduce exposure to PFAS pesticides.
The EPA suggests purchasing organic products if you’re concerned about pesticide exposure. However, the agency notes that even products labeled organic may contain trace amounts of these chemicals.
Tom Gavin joined Everyday Health as copy chief in 2022 after a lengthy stint as a freelance copy editor. He has a bachelor's degree in psychology from College of the Holy Cross.
Prior to working for Everyday Health, he wrote, edited, copy edited, and fact-checked for books, magazines, and digital content covering a range of topics, including women's health, lifestyle, recipes, restaurant reviews, travel, and more. His clients have included Frommer's, Time-Life, and Google, among others.
He lives in Brooklyn, New York, where he likes to spend his time making music, fixing too-old electronics, and having fun with his family and the dog who has taken up residence in their home.
Erica Sweeney has been a journalist for more than two decades. These days, she mostly covers health and wellness as a freelance writer. Her work regularly appears in The New York Times, Men’s Health, HuffPost, Self, and many other publications. She has a master’s degree in journalism from the University of Arkansas at Little Rock, where she previously worked in local media and still lives.
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Trump EPA Approves Its Second ‘Forever Chemical’ Pesticide in Two Weeks. Center for Biological Diversity. November 20, 2025.
Fenton SE et al. Per- and Polyfluoroalkyl Substance Toxicity and Human Health Review: Current State of Knowledge and Strategies for Informing Future Research. Environmental Toxicology and Chemistry. March 1, 2021.
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