A series of recent EPA approvals of fluorinated pesticides has touched off a fight that turns on a deceptively simple question: what, exactly, is a "forever chemical"? The answer determines whether the new products are ordinary crop chemicals or part of the class of persistent compounds regulators around the world are racing to control.
The approvals
Over recent months the EPA has registered several new fluorine-containing pesticides for use on major U.S. crops such as corn, soybeans and wheat, as Chemical & Engineering News reported. Each molecule contains fluorinated carbon, and critics note that some break down in the environment into smaller fluorinated compounds — among them trifluoroacetic acid, or TFA, a highly persistent substance that has been building up in water supplies.
The definition fight
The dispute centers on where to draw the line for PFAS — per- and polyfluoroalkyl substances. The EPA, for regulatory purposes, uses a definition requiring a molecule to have at least two fully fluorinated carbon atoms. By that measure, the agency says, these pesticides are not PFAS. The EPA has pushed back forcefully on coverage suggesting otherwise, issuing a notice it titled a "fact check" that calls the "forever chemical pesticide" label false and says the products cleared its safety review.
But a broader definition used by the Organization for Economic Cooperation and Development — and favored by many researchers and by the European Union — counts any compound with at least one fully fluorinated carbon as PFAS. Under that standard, C&EN reported, the pesticides would qualify. The gap between the two definitions is the whole ballgame: the same molecules are, or are not, "forever chemicals" depending on which one you use.
Health and environmental questions
PFAS as a class have drawn concern because many resist breaking down in the environment and the body, and some have been linked to health harms. For these specific pesticides, the science is contested and still developing. Environmental and health groups, including the Center for Biological Diversity, argue the compounds pose risks — pointing to TFA's persistence in groundwater and to European restrictions on some of the same chemicals. The EPA counters that it conducted toxicity reviews and found no human health risks of concern when the products are used as directed, and notes that comparable compounds have been approved by regulators abroad.
Why it matters
The fight is more than semantic. How PFAS is defined shapes what gets tested, disclosed, restricted and cleaned up — and a category that excludes single-fluorinated-carbon pesticides is far narrower than one that includes them. As TFA turns up more often in water monitoring worldwide, expect the definitional question the EPA has now put back in the spotlight to keep driving both litigation and rulemaking. For now, the agency and its critics are not just disagreeing about risk; they are disagreeing about what the chemicals even are.
