REACH Annex XVII — Proposed Restriction on Terphenyl, Hydrogenated (PHT)

The European Commission has published a draft regulation proposing to add a new entry to Annex XVII of REACH restricting the use and placing on the market of Terphenyl, hydrogenated (PHT) (CAS 61788-32-7).  

Backgroud
PHT, commonly referred to as Partly Hydrogenated Terphenyl, was added to the REACH Candidate List of Substances of Very High Concern (SVHC) in June 2018 due to very persistent and very bioaccumulative (vPvB) properties. Approximately 90% of that volume is used as a heat transfer fluid (HTF) at industrial sites, with the remaining 10% used as a plasticiser in articles and mixtures, and as a processing solvent. As a vPvB substance, PHT accumulates continuously in the environment and in living organisms. Any emissions, even at low levels, are considered a proxy for risk, as there is no concentration threshold below which exposure can be considered safe.

Proposal
The proposed restriction prohibits the placing on the market and use of PHT as a substance on its own, and as a constituent of other substances, in mixtures or in articles, at a concentration of 0.1% w/w or more.
The following uses are exempt from the restriction:

• Industrial heat transfer fluid: PHT used as HTF in the temperature range of 250°C to 350°C at industrial sites operating strictly controlled closed systems (SCCS) with documented technical containment and organisational measures remains permitted on a permanent basis, as no non-regrettable substitutes are currently available
• Defence applications: a permanent derogation applies, reflecting the EU's defence preparedness priorities
• Civilian aerospace applications: the restriction applies after a 10-year transitional period, acknowledging the lengthy certification and recertification processes required in the aviation sector
• Articles and mixtures already placed on the EU market before 18 months after entry into force are also exempt

The regulation is proposed for adoption in the fourth quarter of 2026, with entry into force 20 days after publication in the Official Journal of the EU. The general restriction will apply 18 months after entry into force, with the exception of civilian aerospace applications where the 10-year transitional period applies.

Compliance Implications
PHT is present as a plasticiser in a broad range of articles including cables, automotive parts, aircraft components, electrical and electronic equipment, and construction materials, as well as in sealants, adhesives, paints, inks, and encapsulants. Manufacturers and suppliers in these sectors should assess whether PHT is present in their products or supply chain at concentrations of 0.1% w/w or above, and review Full Material Declarations (FMD) in CDX accordingly ahead of the 18-month implementation deadline.
The full text of the draft regulation is available via the WTO TBT notification G/TBT/N/EU/1205.