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PFHxS added to Persistent Organic Pollutants Regulation

Investigating the growing restrictions on perfluorohexane-1-sulphonic acid and related substances.

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A recent change to European legislation has imposed restrictions on the use of perfluorohexane-1-sulphonic acid (PFHxS). PFHxS is one of a family of chemicals known as ‘per-and polyfluoroalkyl substances’ (PFAS), which are defined as ‘molecules that contain at least one fully fluorinated carbon atom’.

This carbon-fluorine bond makes PFAS extremely resistant to degradation, which has raised concerns about their persistence in the environment. PFAS are commonly used in firefighting foams, as well as in water- and oil-resistant coatings for protective textiles and footwear.

Facing increasing restriction

A subset of PFAS chemicals – C9-14 PFCAs – have been subject to restrictions under REACH Regulation (EC) 1907/2006 since February 2023, and the USA has also begun to introduce legislation to limit the use of PFAS, most notably with the restrictions on total organic fluorine within California AB 1817.

This trend of increasingly stringent restrictions continues with the classification of PFHxS as a ‘Persistent Organic Pollutant’ (POP). These are organic substances which persist and accumulate in the environment, posing a potential risk to human health and ecosystems. They are regulated worldwide by the Stockholm Convention, an environmental treaty established in 2001.

Alexey_Seafarer |

Traces of PFAS chemicals have reportedly been detected in Arctic and Antarctic ice

Legal enforcement

Parties which have signed the convention agree to implement their own regulations to limit the use and release of POPs. In the European Union, this is enforced by the Persistent Organic Pollutants Regulation (EU) 2019/1021, which the UK retained following the exit from the EU in 2021.

The POPs Regulation previously included restrictions on two PFAS substances, perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), as well as their salts and derivatives. In August 2023, Commission Delegated Regulation (EU) 2023/1608 was published, approving the addition of PFHxS to Annex I of the EU POPs regulation, following its addition to the Stockholm Convention in June 2022. This regulation imposes restrictions upon the use of PFHxS both as a substance on its own, as a constituent of mixtures, and in consumer articles. The maximum permitted limits in substances, articles, and mixtures are 25 µg/kg for PFHxS, and 1 mg/kg for its salts and derivatives.

SATRA can help companies to ensure that their products are compliant with this new restriction by arranging for testing for PFHxS and other PFAS chemicals. There are a range of testing options available for PFAS, and our technical experts can assist by advising which package would be best suited for your compliance requirements.

How can we help?

Please contact SATRA’s chemistry team ( for help with testing products for the presence of PFHxS and other PFAS substances.