The Environmental Protection Agency approved three new chemical pesticides on June 30, clearing diflufenican, epyrifenacil, and trifludimoxazin for use in the United States, even as environmental watchdog groups warn the chemicals may break down into persistent "forever chemicals" linked to serious health risks.
The approvals, first reported by the Daily Caller, have drawn sharp criticism from the Center for Biological Diversity and the Center for Food Safety. Both organizations argue the EPA is greenlighting substances that degrade into PFAS compounds, a class of chemicals notorious for lingering in soil, water, and human tissue for years or decades.
The EPA disagrees. And the dispute turns on a question that sounds technical but carries real consequences for American farmland, drinking water, and public health: how many fluorinated carbon atoms does it take to make a chemical a PFAS?
PFAS, per- and polyfluoroalkyl substances, are called "forever chemicals" because the carbon-fluorine bond that defines them is extraordinarily strong. Yale Sustainability has explained that this bond makes them resistant to breakdown in the environment. The question is which chemicals qualify.
The Organization for Economic Cooperation and Development defines PFAS as chemicals containing even a single fluorinated carbon. The National Institute of Environmental Health Sciences takes the same position, considering a chemical PFAS if it has one carbon-fluorine bond. But the Biden administration's EPA drew the line differently. Its Office of Pollution Prevention and Toxics set the threshold at two or more fluorinated carbons, a standard the current EPA says was "deliberate, grounded in extensive scientific evidence that single-fluorinated-carbon molecules lack the persistence and bioaccumulation that define genuine PFAS."
The EPA told the Daily Caller that the OECD "has no regulatory authority on this matter," and pointed out that the OECD itself describes its own definition as merely a "starting and reference point," noting that "individual users may define their own working scope of PFASs for specific activities according to their specific needs."
In a separate statement to Newsweek, the EPA confirmed that diflufenican, epyrifenacil, and trifludimoxazin all consist of single-fluorinated-carbon molecules, placing them below the Biden-era threshold and, in the agency's view, outside the PFAS category entirely.
The Center for Biological Diversity rejects that reasoning. The group told reporters that chemicals with single fully fluorinated carbons "can stick around for generations or longer, which was the basis for their inclusion in the widely accepted PFAS definition."
The organization also raised a more specific concern: that the EPA itself had previously found diflufenican and epyrifenacil will break down into PFAS chemicals, including trifluoroacetic acid, or TFA. The Center for Biological Diversity stated that most PFAS pesticides "are expected to eventually degrade into the forever chemical TFA, which could linger in the environment at harmful levels anywhere from months to decades depending on the chemical properties of the individual pesticide."
The Center for Food Safety added another data point. The group reported that epyrifenacil caused liver tumors in male mice, a claim that, if supported by the underlying study data, raises questions about the adequacy of the EPA's cancer-risk assessment. Separately, the EPA's own review reportedly found "suggestive evidence" linking trifludimoxazin to cancer, though the specific document or proceeding behind that finding is not identified in available reporting.
The Trump administration has not shied from making bold regulatory and executive decisions that provoke opposition. The president's willingness to remove entire federal commissions and reshape agency priorities has defined his second term. The pesticide approvals fit that pattern, the EPA is moving forward on its own scientific judgment, not deferring to international bodies or advocacy groups.
One of the three approved chemicals has already been restricted abroad. In 2025, Denmark's Environmental Protection Agency revoked authorization for 23 pesticides, including diflufenican, partly because of alleged TFA contamination. The Pesticide Action Network reported on Denmark's action.
That international precedent does not bind the U.S. EPA, and the agency made no reference to Denmark's decision in its public statements. But it does create an uncomfortable contrast: a European regulator pulled the same chemical over the same class of concerns that the EPA now dismisses as scientifically unfounded.
The administration has shown it can negotiate complex policy outcomes when the facts support action, as it did when securing the renegotiated Gordie Howe Bridge deal with Canada. The pesticide question, however, involves a different kind of risk calculus, one where the consequences may not surface for years.
The EPA pushed back firmly against any suggestion that its process was inadequate. The agency told the Daily Caller that its registration decisions "applied the same gold-standard review required for every pesticide: comprehensive toxicity testing across species and life stages, evaluation of children's safety and developmental effects, reproductive and chronic health assessments, environmental fate analysis, and Endangered Species Act evaluations with mitigation where warranted."
The agency also stressed that "persistence and bioaccumulation are precisely what EPA's review examines, and they are exactly what single-fluorinated-carbon compounds lack."
That is a direct, substantive rebuttal. The EPA is not waving these chemicals through. It is saying it looked at the science and concluded that the watchdog groups are using an overbroad definition to classify chemicals as dangerous when they do not, in the agency's judgment, behave like true PFAS compounds.
Several important questions remain open. The Daily Caller contacted the U.S. Department of Agriculture for comment, but the USDA did not respond by the time of publication. No information has surfaced about which specific crops or agricultural applications the three pesticides are approved for, or which manufacturers hold the registrations.
The regulatory docket numbers for the three approvals, EPA-HQ-OPP-2021-0435-0052, EPA-HQ-OPP-2022-0354-0090, and EPA-HQ-OPP-2022-0649-0042, are publicly available on regulations.gov, but the underlying review documents have not been widely discussed in public reporting. Whether the EPA's own earlier findings about TFA degradation products contradict its current position is a question the watchdog groups have raised but that the EPA has not directly addressed in its public statements.
It is also unclear whether the three pesticides are now in active commercial use or whether a deployment period follows approval. That distinction matters. If farmers are already spraying these chemicals, the debate is no longer theoretical.
The Trump administration has faced pressure from multiple directions this term, from congressional Republicans demanding data on immigration policy to critics questioning personnel decisions across the executive branch. The pesticide approvals represent a quieter but potentially more consequential front.
This is not a case of clear-cut regulatory failure. The EPA has articulated a defensible scientific position. The Biden administration itself drew the PFAS line at two fluorinated carbons, not one. The current EPA is applying that same standard. The OECD's broader definition is explicitly non-binding and self-described as a reference point, not a mandate.
But the watchdog groups are not making frivolous claims, either. The liver-tumor finding in mice, the TFA degradation pathway, and Denmark's decision to pull diflufenican all deserve serious scrutiny, not dismissal as activist noise. If the EPA's own prior research identified TFA as a breakdown product of these chemicals, the public deserves to see that analysis and understand why the agency concluded it does not pose an unacceptable risk.
The administration has shown a willingness to weather political criticism when it believes its decisions are sound. That same confidence should extend to full transparency about the science behind these approvals.
Conservative voters do not want a regulatory state that blocks every useful chemical based on activist pressure. But they also do not want their families drinking water contaminated with compounds that a European government already banned. The EPA owes the public more than a press statement. It owes them the data.