Denmark’s environmental agency suspects that five insecticides still on the market can break down into the forever chemical TFA. Environment Minister Maria Reumert Gjerding says she is ready to ban them.
DR reported on August 9, 2026 that Miljøstyrelsen has a grounded suspicion about the active substance lambda-cyhalothrin and four other PFAS substances. All five are still permitted for sale and use in Denmark.
The agency has awarded 1.8 million kroner to the geological data center GEUS for a research project. According to DR, the project will examine whether the substances form TFA in amounts that threaten groundwater and drinking water. The results will show whether there is a basis for withdrawing the approvals of the active substances.
Sales of products containing lambda-cyhalothrin totaled 3,326 kilos in 2024, per the Ministry of the Environment. The same ministry says sales have increased since 2015. Lambda-cyhalothrin is used in insect control products sold on the Danish market.
TFA is an ultra short chain PFAS compound, described as a forever chemical. It is not used as a pesticide itself, but can form when certain fluorinated pesticides break down in soil and the environment. The European Chemicals Agency, ECHA, updated its assessment of TFA in spring 2026 and now considers the substance harmful to foetuses and to human reproduction.
TFA was detected in 902 Danish drinking water boreholes between 2021 and 2024. According to the Ministry of the Environment, that equals 40 percent of the boreholes examined. Miljøstyrelsen states in its press release that current TFA levels in drinking water boreholes are not dangerous to humans.
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Gjerding, who represents SF, told DR that products containing lambda-cyhalothrin will be banned if the research confirms the ministry’s fears. The condition is that the substances form TFA to a degree that threatens groundwater and drinking water. She said Danes should be able to trust that the water from the tap is clean both today and in the future.
Precautionary principle under review
The minister has also asked her ministry to assess the options for a possible ban on pesticides containing the five active substances. As reported by DR, that assessment would be based on the European Union’s precautionary principle. It is to be carried out while the research is pending.
In 2025, Miljøstyrelsen recalled 33 pesticides after studies documented that the substances broke down into TFA above the limit value. Under the pesticide rules, regulators must document both that a substance degrades into TFA and that it happens above the required threshold. Only then can a substance be recalled.
The government has previously announced plans for a national spraying ban in vulnerable groundwater forming areas. Denmark has already moved against PFAS pesticides in earlier rounds of regulation.
