On November 9, 2023, the Court of Justice of the European Union (CJEU) confirmed the validity of the European Chemicals Agency's (ECHA) decision ED/71/2019 of July 4, 2019, which includes 2,3,3,3-tetrafluoro-2-(heptafluoropropoxy)propionic acid (or HPFO-DA) in the list of substances identified for eventual inclusion in Annex XIV of the REACH regulation.

Inclusion of a substance in this annex has two consequences: on the one hand, the substance is subject to an expiry date, after which no further use will be permitted unless authorization has been granted by ECHA following an evaluation process. On the other hand, inclusion in Annex XIV is accompanied by the setting of a deadline for submitting applications for authorization, which is the "deadline for submitting an application for authorization to continue to place the substance on the market or use it after the expiry date, pending a decision on its application for authorization".

Chemours Netherlands, a company based in the Netherlands, imports and supplies HPFO-DA, a substance used in the manufacturing process of fluoropolymers. This manufacturing technique goes by the trade name GenX. In March 2019, the Dutch authorities submitted a dossier to ECHA with a view to classifying HPFO-DA as a substance of very high concern under Article 57(f) of the REACH Regulation. The latter includes in Annex XIV "substances - [...] which do not meet the criteria set out in points (d) or (e) - for which there is scientific evidence that they may have serious effects on human health or the environment which give rise to a level of concern equivalent to that arising from the use of other substances listed in points (a) to (e) [...]". Paragraphs a) to e) of Article 57 allow substances identified as carcinogenic, mutagenic or toxic to reproduction (CMR substances); persistent, bioaccumulative and toxic (PBT substances) or very persistent and very bioaccumulative (vPvB substances) to be included in Annex XIV.

After studying the Netherlands' request, ECHA has decided to include HFPO-DA on the list of identified substances with a view to its eventual inclusion in Annex XIV. On September 24, 2019, Chemours lodged an appeal with the European Union General Court (EUGC) to have this decision annulled. On February 23, 2022, the TUE rejected Chemours' application (T-636-19), which Chemours then appealed to the CJEU.

In rejecting Chemours' application, the CJEU noted that to identify a substance as being of very high concern under Article 57(f), "it must be established, on the basis of scientific evidence, that the substance may have serious effects on human health or the environment, and that these effects give rise to a level of concern equivalent to that aroused by CMR, PBT or vPvB substances.) These conditions are cumulative [...]". This means that not only the intrinsic properties of the substance must be considered, but also other relevant factors when assessing whether the level of concern is equivalent.

As such, the equivalent level of concern can be characterized as soon as the effects of the substance are sufficiently serious or irreversible. On the basis of a weight-of-evidence approach, ECHA is justified in characterizing this equivalent level of concern on the basis of a combination of individual effects which, taken together, make it possible to consider that the effects are probable and serious. Moreover, the list of criteria set out in Article 57(f) for identifying a substance as extremely dangerous, namely its "endocrine-disrupting properties [...] persistent, bioaccumulative and toxic properties or very persistent and very bioaccumulative properties", is indicative and non-exhaustive, so that a substance need not present all these characteristics to be qualified as extremely dangerous.

Thus, in the present case, ECHA was right to include HFPO-DA in Annex XIV under Article 57(f) of the REACH Regulation, finding it to be a persistent, mobile substance with long-range transport potential and probable adverse effects on human health and the environment.

Although HPFO-DA is not used as an active substance in plant protection products, the CJEU's decision is not without interest: HPFO-DA belongs to the family of PFASs, per- and polyfluoroalkylated substances that are among the "forever chemicals", and as revealed by the associations PAN Europe and Générations futures in a report published in November 2023, many pesticides also contain PFASs, in the form of active substances or residues.