Persistent Organic Pollutant PFHxS banned in Great Britain

On 16 November 2023, an amendment to the Persistent Organic Pollutant (POPs) Regulation came into force in Great Britain (England, Scotland, and Wales). The amendment adds perfluorohexane sulfonic acid (PFHxS), its salts, and PFHxS-related compounds to the list (Part A of Annex 1) of substances whose production, placing on the market and use are prohibited under the POPs Regulation.

PFHxS substances

PFHxS substances belong to the group of compounds collectively known as per- and polyfluoroalkyl substances (PFAS). They are used as surfactants in a wide range of industrial and commercial products such as food packaging, stain and water-resistant materials, fire-fighting foams, and paint additives. PFHxS, its salts, and PFHxS-related compounds were added to Annex A of the Stockholm Convention at COP-10 in June 2022 without any specific exemption. Each Party to the Convention is required to prohibit the chemicals listed in Annex A and/or to take the necessary legal and administrative measures to eliminate their production, use, import and export. The substances were banned in the EU in August 2023.

PFHxS, its salts, and PFHxS-related compounds are defined is as follows:

1. Perfluorohexane sulfonic acid (CAS No. 355-46-4, PFHxS), including branched isomers.

2. Its salts.

3. Any substance that contains the chemical moiety C₆F₁₃SO₂- as one of its structural elements and that potentially degrades to PFHxS.

PFHxS substances are highly resistant to chemical, thermal and biological degradation due to their strong carbon-fluorine bonds. This resistance to degradation makes them persistent in the environment. Numerous studies have documented elevated levels of PFHxS in soil, water and a variety of ecosystems. Human exposure to PFHxS occurs mainly through ingestion of food and drinking water but also in indoor environments through dust or from consumer products containing PFHxS or its precursors.

Amendment to POPs Regulation

The Persistent Organic Pollutants (Amendment) (No. 2) Regulations 2023 (Statutory Instrument 2023 No. 1217) amend Part A of Annex 1 to Regulation (EU) 2019/1021 of the European Parliament and of the Council on persistent organic pollutants by adding PFHxS, its salts, and PFHxS-related compounds.

The amendment specifies the following concentration limits up to which the newly listed substance may be present as an unintentional trace contaminant:

1. Where the sum of the concentrations of PFHxS and any of its salts present in a substance, mixture or article is equal to or below 0.025 mg/kg (0.0000025% by weight).

2. Where the sum of the concentrations of any PFHxS-related compounds present in a substance, mixture or article is equal to or below 1 mg/kg (0.0001% by weight).

3. Where the sum of the concentrations of PFHxS, any of its salts, and any PFHxS-related compounds present in concentrated fire-fighting foam mixtures that are to be used or are used in the production of other fire-fighting foam mixtures is equal to or below 0.1 mg/kg (0.00001% by weight).

A full impact assessment has not been carried out for this instrument, as it is expected to have minimal or insignificant effects on the private, voluntary, or public sectors. Instead, a de minimis assessment has been carried out, recognising that this instrument may impose some costs on businesses. However, the overall estimated net impact is expected to be less than £5 million per year.