Denmark’s PFAS pesticide phase-out enters its final season — and five more substances are under investigation

The pesticide restrictions from the Danish Environmental Protection Agency (EPA), Miljøstyrelsen, are entering a new phase.

Last year, the Danish EPA highlighted 6 active ingredients in plant protection products(PPP) under suspicion of degrading into perfluoroalkyl and polyfluoroalkyl substances(PFAS). PFAS are a group of synthetic chemicals known as "forever chemicals" as they do not break down easily in the environment or the human body.

In 2025, 33 plant protection products were withdrawn, and the last products are now nearing the end of their respective phase-out periods, making this the final autumn in which the affected products can still be used.

While we are entering this final stretch of the phase-out period, the Danish EPA has recently announced a research project to investigate five additional PFAS active substances currently approved in Denmark. Similarly to the 2025 bans, the new project will research whether the suspected products degrade into the PFAS called trifluoroacetic acid (TFA) a persistent and highly mobile PFAS compound that can reach groundwater. The research will focus on whether the potential TFA findings are at levels relevant to groundwater protection.

For PPP registration holders, the two developments are connected but require different considerations: one concerns products already being phased out; the other concerns active substances where the regulatory outcome is not yet known.

PFAS pesticides in Denmark: a quick overview 

• 33 plant protection products were withdrawn in Denmark in 2025 following evidence of TFA formation.
• 2026 is the final phase-out season for the remaining affected products.
• Five additional active substances are now (as of 9th August 2026) under investigation: lambda-cyhalothrin, oxathiapiprolin, picolinafen, pyroxsulam and tefluthrin.
• DKK 1.8 million has been allocated to GEUS research into potential TFA formation.
• The new investigation is not itself a withdrawal decision.

The 2025 PFAS pesticide withdrawals are now reaching their final phase

In 2025, the Danish EPA withdrew approval for 33 plant protection products containing six active substances associated with the formation of trifluoroacetic acid (TFA):

• Fluazinam
• Fluopyram
• Diflufenican
• Mefentrifluconazole
• Tau-fluvalinate
• Flonicamid

The withdrawals followed scientific work showing that certain fluorinated pesticides can degrade into TFA, a persistent and highly mobile PFAS compound that can reach groundwater.

The products were given different phase-out periods depending on the individual approval. The remaining products are now entering their final autumn before the 2025 withdrawals are fully phased out.

Five additional PFAS active substances are now being investigated

The Danish PFAS discussion is not ending with the 2025 withdrawals.

The Danish EPA has now announced funding for research into five additional PFAS active substances currently approved in Denmark:

• Lambda-cyhalothrin
• Oxathiapiprolin
• Picolinafen
• Pyroxsulam
• Tefluthrin

The substances have been identified for further investigation because they potentially transform into TFA. At this moment, they have not been withdrawn.

The new research project, carried out by the Geological Survey of Denmark and Greenland (GEUS), will investigate whether the substances form TFA under relevant conditions and whether the resulting concentrations could affect groundwater and drinking-water protection.

The Danish EPA has allocated approximately DKK 1.8 million to the project.

One of the substances attracting particular attention is lambda-cyhalothrin. Miljøstyrelsen reports that sales of products containing the active substance reached 3.326 kg in Denmark in 2024 and have increased since 2015.

The agency has stated that there is a substantiated suspicion that lambda-cyhalothrin can form TFA and that the new research will determine whether this occurs at levels that could lead to further regulatory action.

The Danish Ministry of Environment has also highlighted the issue and the possibility of further action depending on the research findings.

The important distinction is that these five active substances remain approved while the evidence is being established.