The case against diflufenican is now clear-cut. This herbicide, widely applied on winter cereals across Europe, breaks down into trifluoroacetic acid (TFA), an ultra-persistent "forever chemical" that is accumulating in groundwater and polluting our drinking water. Evidence shows that the legal threshold for groundwater is breached by diflufenican under real-use conditions. The European Commission must immediately propose its non-renewal in accordance with EU law.
Diflufenican has been approved in the EU since 2009. Its approval was already supposed to expire in 2018, but it has been repeatedly extended without evaluation, now until the end of 2026. The substance contains a trifluoromethyl group (–CF₃), a chemical building block scientifically recognised, as a precursor of TFA, an ultra-short-chain PFAS.
TFA is extraordinarily persistent, very mobile in water, impossible to remove through conventional treatment, and is toxic. It is currently under assessment for classification as ‘Persistent, Mobile and Toxic’ (PMT), and ‘toxic to reproduction’, with evidence pointing to reproductive and developmental harm. Under EU pesticide law, this makes TFA a "relevant metabolite," triggering a groundwater limit of 0.1 µg/L.
Several studies point to diflufenican degradation into TFA and groundwater contamination above this limit. Namely, a study by the Geological Survey of Denmark and Greenland (GEUS) found TFA concentrations of 0.12 µg/L in groundwater following representative use of diflufenican on winter cereals. [1] As a result, Denmark has already withdrawn authorisations for products containing diflufenican. A 2024 study identified diflufenican as one of the pesticides with the highest TFA load of any substance in use. [2] A 2025 study confirmed it has the greatest TFA leaching potential into groundwater among PFAS pesticides, particularly for cereal applications [3]. Moreover, multiple data consistently demonstrate that the background TFA concentrations in groundwater are by far exceeding the limit of 0.1 µg/L across Europe.
Worryingly, EFSA’s recent peer review on the risk assessment of diflufenican in February 2026 failed to identify TFA formation as a critical area of concern — despite being aware of the relevant evidence. The industry consortium had not reported TFA formation in its application dossier, as the studies submitted were not of sufficient duration to detect it. But the absence of industry data is not an excuse for inaction: EU law explicitly requires regulators to take into account the latest scientific and technical knowledge. Independent studies documenting TFA formation from diflufenican under real-use conditions were available. EFSA failed to draw the necessary conclusions from them.
The European Commission and Member States will meet on 5-6 May, where the future of diflufenican's approval may be on the table [4]. Ahead of the meeting, PAN Europe, and its members Générations Futures, PAN Germany and Global 2000, have urged the Commission in a letter to present the non-renewal, in line with the science, the law, and the protection of Europe's water.
Read our joint letter to the Commission on diflufenican
Notes:
[1] Danish Environmental Protection Agency, 2024. TriFluPest. Trifluoreddikesyre (TFA) fra pesticider. Bekaempelsesmiddel-forskning nr. 230.
[2] Joerss, et al., 2024. Pesticides can be a substantial source of trifluoroacetate (TFA) to water resources. Environment International, Volume 193, 2024, 109061, ISSN 0160–4120. https://doi.org/10.1016/j.envint.2024.109061.
[3] Diehle et al., 2025. Trifluoroacetate leaching potential from fluorinated pesticides: an emission estimation and FOCUS modelling approach. Environmental Sciences Europe, Volume 37, 161, 2025. https://doi.org/10.1186/s12302-025-01215-5
[4] Agenda: 5-6 May 2026: Standing Committee on Plants, Animals, Food and Feed - Section Phytopharmaceuticals Legislation
