ANSWERS · 4 OCT 2026

Is PFHxA (CAS 307-24-4) restricted under REACH Annex XVII? Give the entry number, the uses covered, the concentration limits and the application dates, with citations.

Yes. PFHxA is restricted under REACH Annex XVII entry 79, "Undecafluorohexanoic acid (PFHxA), its salts and PFHxA-related substances". The entry was inserted by the restriction regulation published as OJ L 2024/2462 ^[1]. The firefighting-foam training and public-service limits have applied since 10 April 2026. The consumer-product limits apply from 10 October 2026, six days from now. The current consolidated REACH text (02006R1907-20260511) also shows entry 79 as amended by Regulation (EU) 2025/1090 ^[2].

Approach: I checked ECHA's Annex XVII restrictions list and the current consolidated text of REACH. ECHA lists entry 79 as a group entry (PFHxA, its salts and related substances) rather than under CAS 307-24-4, so I matched it by substance name.

Scope of the entry

Covered: PFHxA, its salts, and PFHxA-related substances. These are substances with a linear or branched C5F11- group attached directly to another carbon atom, or a C6F13- group.
Excluded: C6F14; C6F13-C(=O)OH, C6F13-C(=O)O-X′ and C6F13-CF2-X′; and C6F13- groups attached directly to an oxygen atom at a non-terminal carbon.
"Related substances" means substances that, based on their molecular structure, may degrade or be transformed into PFHxA.

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Concentration limits. In every paragraph the limit is the same:

25 ppb for the sum of PFHxA and its salts, or
1 000 ppb for the sum of PFHxA-related substances.

For paragraphs 1 and 2 these are measured in homogeneous material. The concentrations are "equal to or greater than" thresholds ^[2]^[3].

Uses covered and application dates

Para.	Uses covered	Applies from
4	Firefighting foams and concentrates used for training and testing. Functional testing of firefighting systems is exempt if all releases are contained.	10 April 2026
4	Firefighting foams and concentrates used by public fire services. Exempt: industrial fires at establishments covered by Directive 2012/18/EU, where the foams and equipment are used for that purpose only.	10 April 2026
1	(a) Textiles, leather, furs and hides in clothing and related accessories for the general public. (b) Footwear for the general public. (c) Paper and cardboard food contact materials under Regulation (EC) No 1935/2004. (d) Mixtures for the general public. (e) Cosmetic products under Regulation (EC) No 1223/2009.	10 October 2026
2	Other textiles, leather, furs and hides for the general public, i.e. not clothing or accessories	10 October 2027
5	Firefighting foams and concentrates for civil aviation, including civilian airports	10 October 2029

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Exemptions and transitional rules

Paragraphs 1 and 2 do not apply to:
- personal protective equipment in risk category III under Regulation (EU) 2016/425 (Annex I points (a), (c) to (f), (h) and (l));
- devices under the medical device regulation, (EU) 2017/745;
- devices under the in vitro diagnostic regulation, (EU) 2017/746;
- construction textiles.
Paragraphs 1, 2, 4 and 5 do not apply to: C6F13- substances attached to a sulphur atom that are already banned under Annex I of the POPs Regulation (EU) 2019/1021.
Existing stock:
- Paragraph 1 does not apply to articles and mixtures placed on the market before 10 October 2026.
- Paragraph 2 does not apply to articles placed on the market before 10 October 2027.

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Overlap with entry 82 (PFAS in firefighting foams). Entry 82 sets a general limit of 1 mg/L for the sum of all PFAS in firefighting foams from 23 October 2030. It carves out PFHxA, its salts and related substances "for uses restricted under entry 79". However, those substances still count towards the PFAS sum when the concentration is determined ^[5].

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