Two further substances have been added to the Candidate List this year: n-hexane and bisphenol AF (BPAF). Both were carried onto the UK REACH Candidate List under the faster alignment process with ECHA covered in our earlier posts, and both are worth a closer look — not because they’re obscure, but because they sit in supply chains that don’t always think of themselves as “chemical” businesses.
n-Hexane (CAS 110-54-3)
n-Hexane was identified as an SVHC primarily on reproductive toxicity grounds. It’s a widely used solvent, and it’s the kind of substance that shows up as a supporting ingredient rather than a headline one — which is exactly why it’s easy to miss in a screening exercise.
Where it turns up: contact adhesives and cements (particularly in footwear, leather goods and upholstery manufacturing, where n-hexane-based glues have a long history), some solvent extraction and degreasing processes, and printing inks. If your supply chain touches adhesives, bonding processes or solvent-based cleaning, it’s worth checking rather than assuming.
Who it’s likely to affect: adhesive and sealant formulators, footwear and leather manufacturers, printers, and any business using solvent-based bonding or cleaning processes in production.
Bisphenol AF (CAS 1478-61-1)
Bisphenol AF was identified on endocrine-disrupting grounds — the same basis that put Bisphenol A on the Candidate List some years ago, and BPAF is structurally close enough to BPA that this isn’t a surprise.
Where it turns up: BPAF’s most significant industrial use is as a curing and crosslinking agent in high-performance fluoroelastomers (FKM rubber) — the seals, gaskets and O-rings used in demanding environments across aerospace, defence, automotive and oil & gas applications. It also appears in some specialty polymer and resin formulations.
Who it’s likely to affect: this one is particularly relevant for defence and aerospace supply chains. Fluoroelastomer seals and gaskets are everywhere in platforms and equipment that need to withstand extreme temperatures, fuels and chemicals — and BPAF is a common curing agent in exactly that material class. If you buy in sealed or gasketed components rather than raw elastomer, this can be an easy one to overlook.
What this means
Both substances now carry the same duties as any other Candidate List entry: Article 33 communication obligations apply where either is present in an article above 0.1% weight by weight, and both should be logged as candidates for future authorisation or restriction consideration.
What to do next
- Check adhesive, sealant and solvent formulations specifically for n-hexane — including legacy or imported products where reformulation may not have happened yet.
- If you buy, use or specify fluoroelastomer seals, gaskets or O-rings, ask suppliers directly whether BPAF is used as a curing agent in their material — don’t assume it’s been substituted just because alternatives exist.
- Update supplier declarations and safety data sheets to reflect both substances specifically, rather than relying on a general SVHC statement.
- Flag both on your substance risk register — BPAF in particular is worth watching given the precedent set by Bisphenol A’s own regulatory path after Candidate List listing.
How we can help
We’re helping clients check adhesive and sealant formulations for n-hexane, and trace fluoroelastomer components back to confirm BPAF exposure — particularly across defence and aerospace supply chains where sealed components are everywhere but rarely questioned. Get in touch if you’d like us to run this against your own product range.
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