A coalition of public health and environmental groups is suing the EPA over its approval of the PFAS-based pesticide isocycloseram, which studies link to reduced testicle size, lower sperm counts and liver damage in rats. Plaintiffs argue the EPA relied too heavily on industry data, failed to apply child-protection safety margins and overlooked independent findings — including fetal skeletal malformations reported by Australian regulators. The chemical persists for centuries, breaks into dozens of additional PFAS compounds, and may harm wildlife and pollinators. The case raises broader concerns about PFAS in pesticides and industry influence within EPA chemical safety leadership.
Health Groups Sue EPA Over PFAS Insecticide Linked to Testicular Damage in Rats
Suit marks a conflict between health secretary RFK Jr’s Make America Healthy Again movement and Maga elements in the Trump administration.Photograph: Pablo Martínez Monsiváis/AP(Photograph: Pablo Martínez Monsiváis/AP)
A coalition of public health and environmental groups has filed suit against the U.S. Environmental Protection Agency (EPA), challenging the agency’s approval of the PFAS-based insecticide isocycloseram. Plaintiffs say industry-funded studies and the EPA’s own risk assessment link the chemical to reduced testicle size, lower sperm counts and liver damage in rats — risks they argue were not adequately addressed before approval.
Who’s Suing and Why
The suit, led in part by the Center for Biological Diversity, contends the EPA ignored statutory child-protection requirements and relied heavily on industry-submitted data instead of independent science. Nathan Donley, the center’s environmental health science director and a plaintiff, warned the pesticide’s use on food crops could disproportionately threaten children and developing fetuses.
What Is Isocycloseram and Why It Matters
Isocycloseram is a PFAS-containing pesticide approved for use on many food crops (including apples, lettuce, tomatoes, broccoli, wheat and almonds) and on turf such as lawns and golf courses. PFAS — per- and polyfluoroalkyl substances — are a large class of persistent synthetic chemicals often called "forever chemicals" because they resist environmental degradation and accumulate in organisms over time.
According to the EPA’s human health risk assessment, long-term dietary exposure to isocycloseram in rats was associated with “reduced testes size, increased incidence and severity of tubular degeneration in the testes, reduced sperm and cellular debris in the epididymis.” Australian regulators also reported fetal skeletal malformations in rats, and some studies raise carcinogenicity concerns.
Environmental And Ecological Concerns
Isocycloseram persists in the environment for at least hundreds of years and reportedly degrades into roughly 40 smaller PFAS compounds, some more persistent than the parent chemical. Plaintiffs cite EPA science predicting significant adverse effects on more than 1,000 threatened and endangered species. The chemical also appears highly toxic to pollinators; models suggest insects could encounter concentrations many times higher than lethal levels near treated fields.
Regulatory Criticisms And Political Context
Environmental groups blame the EPA’s Office of Chemical Safety and Pollution Prevention leadership for the approval, noting the office now includes several former industry lobbyists. The complaint says the EPA did not apply the Food Quality Protection Act’s default 10-fold safety margin intended to protect children unless there is strong scientific evidence to waive it, and that the agency failed to account for cumulative exposures to multiple chemicals.
"Approval of this dangerous pesticide spotlights how industry influence is undermining chemical oversight," said Nathan Donley.
An EPA spokesperson told the Guardian the agency does not comment on active litigation but asserted the agency remains "committed to tackling PFAS and protecting children's health" and described its work as based on "gold-standard science."
Broader Picture
A 2023 analysis of EPA data found that at least 60% of active ingredients approved for federal pesticide use in the prior decade meet the most widely accepted definitions of PFAS, raising broader questions about the prevalence of long-lived fluorinated compounds in agriculture and turf management.
What’s Next
The lawsuit will test whether the EPA’s approval adequately considered independent science, child-protection mandates and ecological risks. Plaintiffs say they intend to block use of isocycloseram until its hazards are fully evaluated; the agency maintains its assessment process is scientifically rigorous.
Help us improve.
