Why 'No REACH Restriction' Can Be Wrong: Annex XVII Entries, Appendices, and How to Check a Photoinitiator Properly

Last reviewed: 18 September 2026. Annex XVII is amended several times a year. The structure described here has been stable for years; the substance lists have not.

Every few months a formulator tells us they have checked a photoinitiator for REACH restrictions and found none. Sometimes they are right. Sometimes they have checked the wrong page, and the substance is restricted after all. The second case is common enough that it is worth explaining why it happens, because the reason is structural rather than careless.

Annex XVII has two layers, and only one of them is shown to you

Annex XVII of REACH is the restriction annex. When people talk about "the REACH restriction list", they usually mean its numbered entries: the list that runs from 1 up to somewhere in the seventies, each one covering a substance, a group, or a use.

What that list does not show you is the second layer. Several of those entries carry appendices, numbered separately, and the appendices hold the actual substance lists that the entry applies to. A substance can be fully caught by an entry without ever appearing in the entry list itself, because what appears there is the entry, not the substances underneath it.

This is not a loophole or an obscure drafting quirk. It is how the annex is organised, and it is entirely deliberate. It is also invisible to anyone who looks up a CAS number in a restriction database and reads the result as definitive.

The worked example: TPO

TPO, diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, CAS 75980-60-8, is a clean illustration.

Search for TPO in the usual places and you will often find no substance-specific restriction entry. That result is accurate as far as it goes, and it is also misleading. Commission Regulation (EU) 2025/1731 inserted TPO into Appendix 6 to Annex XVII, under index number 015-203-00-X and EC number 278-355-8. Appendix 6 sits under Entry 30. So TPO is restricted, by way of an appendix, without ever having an entry of its own.

The correct statement is therefore narrower and more precise than either "TPO is banned" or "TPO has no restriction":

• TPO has no substance-specific Annex XVII entry.
• TPO is listed in Appendix 6, and is therefore subject to the Entry 30 restriction.
• Entry 30 restricts placing on the market and use for supply to the general public. Industrial use in a formulation is not general public supply.

If you had checked only the entry list, you would have concluded there was no restriction at all. If you had read a headline, you might have concluded TPO was banned. Both are wrong, and the accurate answer sits between them.

A second example, on a different appendix

Benzophenone, CAS 119-61-9, follows a similar pattern on a different appendix. Commission Regulation (EU) 2023/1132 inserted it into Appendix 2 to Annex XVII, under Entry 28, applying from 1 December 2023. That entry deals with carcinogens, mutagens and substances toxic to reproduction where supply to the general public is concerned.

Benzophenone is a good reminder that this cuts both ways. It is a small, cheap, extremely common photoinitiator and photosensitiser. It is also harmonised as Carc. 1B. Plenty of formulators still treat it as unremarkable because nothing in the entry list announces otherwise.

Why this matters more for photoinitiators than for most chemistries

Photoinitiators are a concentrated case. Several of the widely used grades have moved through the SVHC process and into restriction or authorisation discussion over the last six years, and the ones that have done so have landed in different instruments:

Grade	CAS	Where it sits
BP	119-61-9	Annex XVII, Appendix 2 to Entry 28, from 1 Dec 2023
369	119313-12-1	Candidate List (SVHC) since 16 Jan 2020; harmonised Repr. 1B
907	71868-10-5	Candidate List (SVHC) since 16 Jan 2020; harmonised Repr. 1B
TPO	75980-60-8	Candidate List since 2023; harmonised Repr. 1B from 1 Sep 2025; Annex XVII Appendix 6 via Reg. (EU) 2025/1731; proposed for Annex XIV
379	119344-86-4	Candidate List since 23 Jan 2024; harmonised Repr. 1B; proposed for Annex XIV

Note that these are five different situations, not one. The Candidate List is not a restriction. A harmonised classification is not a restriction either. Annex XVII is a restriction. Annex XIV, if a substance reaches it, is an authorisation requirement. When someone says a photoinitiator "is regulated", that sentence carries almost no information until you know which instrument they mean.

How to check a substance properly

Five steps, in this order.

Start with the consolidated text of Annex XVII on EUR-Lex, not a database summary. Search the document for the CAS number, and then search it a second time for the substance name. Appendices are part of the same document; if you only read the entry list you will miss them.

Check the Candidate List separately, and note its date. It is updated roughly twice a year and the count changes. A statement about SVHC status without a date is not worth much.

Check Annex VI of the CLP Regulation for a harmonised classification. This matters because it determines whether the pictogram on your SDS is law or the supplier's own judgement. For most photoinitiators it is the latter.

Check Annex XIV if the substance has been through the authorisation process, and check whether there is a pending recommendation. A recommendation is not law, but it is the thing you plan around.

Finally, read your supplier's SDS, Sections 3 and 15. Section 15 is where the regulatory information sits, and section 3 carries the classification. If the revision date is more than a year old on a substance with an active regulatory file, ask for a current one.

The part that is genuinely difficult

Two things make this harder than it should be.

The first is that instruments move at different speeds. A substance can be on the Candidate List for six years while its restriction is still being debated. Between those events there is no clean status, and the honest answer to "is this restricted?" is a paragraph rather than a word.

The second is that the annex is amended constantly, and secondary sources lag. We have seen SDS documents in circulation carrying classifications that were superseded years earlier.

So the practical rule is this: check the primary text, date-stamp whatever you conclude, and re-check when the substance has an open file. A compliance answer without a date is a liability of its own.

What we can tell you

We supply TPO, TPO-L, 369, 907, 379, BP and the rest of the range described above. If you tell us the destination market and the end use, we will tell you which regulatory file each one sits in, and we will send the current SDS so you can check it yourself rather than take our summary.

If the answer is that a product you are using has become awkward and we have nothing better to offer, we will say that too.