Irgacure 184 / Omnirad 184 Regulatory Status: The Withdrawn Repr. 1B Classification and What to Use Instead
September 18, 2026 · Technical
Last reviewed: 18 September 2026. Regulatory status changes; check the sources linked at the end before you act on this.
In late 2025 a reclassification notice for Irgacure 184 appeared, then disappeared again. Formulators who saw the first announcement have been asking us ever since whether 184 is still safe to specify, whether they need to reformulate, and what they should switch to. The short answer is that 184 is not restricted and never became restricted. The longer answer involves a distinction that matters more than the headlines did: who issued the classification, and whether it survived.
What actually happened, in order
184 (CAS 947-19-3, 1-hydroxycyclohexyl phenyl ketone) is sold by IGM Resins under the Omnirad name. Omnirad is the current name for the grades BASF used to sell as Irgacure and Darocur, so Omnirad 184, Irgacure 184 and Darocur 184 are the same substance from the same producer. If you find a supplier offering all three as separate products, they are either confused or hoping you are.
On 29 August 2025, IGM self-classified 184 as Reprotoxic Category 1B. The company announced the change on 1 September 2025, and the announcement travelled. Then it was reversed. IGM published a follow-up statement saying it had decided to withdraw the self-classification, and that the classification would remain as it stood before 29 August 2025. At the time of writing that withdrawal still stands.
Why the distinction between self-classification and harmonised classification matters
This is the part that got lost in the retelling. In the EU, a substance can end up with a hazard classification by two different routes.
The first is a harmonised classification, agreed at EU level and added to Annex VI of the CLP Regulation. That is binding on everyone. If a substance has one, you cannot legally classify it more leniently.
The second is a self-classification, made by a manufacturer or importer on the basis of its own data. It is binding on that company for its own labelling and SDS. It does not bind its competitors, and it is not the same thing as an EU decision. Other suppliers of the same substance are free to reach a different conclusion, and legally they may be right to.
What happened in August 2025 was the second kind. No harmonised classification for 184 exists. There is no REACH restriction on 184, no SVHC listing, and no entry on the Candidate List. IGM's own reclassification was withdrawn by IGM.
Where things actually stand
| Question | Answer as of September 2026 |
|---|---|
| Is there an EU harmonised classification for 184? | No. |
| Is 184 on the REACH Candidate List (SVHC)? | No. |
| Is 184 restricted under REACH Annex XVII? | No. |
| Is there a producer self-classification? | One was issued by IGM on 29 Aug 2025 and then withdrawn. |
| Should you do anything? | Check your supplier's current SDS. If it still shows Repr. 1B, it is out of date. |
Note the last row. Some SDS documents in circulation still carry the withdrawn classification, because revising an SDS takes time and not every distributor prioritises it. If yours shows Repr. 1B, that is a paperwork lag rather than a change in the law. Ask your supplier for the current revision.
What this means if you specify 184
For most users the practical answer is: keep using it, and keep an eye on it. Nothing you are doing is unlawful, and no reformulation is forced.
Two situations do deserve action. If you supply customers who ask for regulatory declarations, you will need to explain the timeline, and it helps to have that explanation in writing before the question arrives rather than after. And if 184 sits in a formulation that would be expensive to change, this is a reasonable moment to identify a second source. Not because 184 is likely to be restricted, but because a single-source dependency on any photoinitiator is a risk that costs less to remove now than in a hurry.
Substitution options, and what each one costs you
There is no drop-in replacement for 184, and anyone who tells you otherwise is selling something. The alternatives are close in some respects and different in others. What follows is our honest read based on the technical data we hold.
| 184 | 1173 | TPO | TPO-L | |
|---|---|---|---|---|
| CAS | 947-19-3 | 7473-98-5 | 75980-60-8 | 84434-11-7 |
| Form | White crystalline powder | Liquid | Light yellow powder | Liquid |
| Absorption | 244 / 280 / 330 nm | 244 / 278 / 322 nm | 273 / 370 nm | ~273 / 380 nm |
| Melting range | 45 to 50 °C | Liquid at room temperature | 85 to 95 °C | Liquid at room temperature |
| Typical loading | 3 to 5% as PI, 1 to 3% as co-initiator | 3 to 5% | 1 to 3% coatings, 5 to 10% inks | As TPO |
| Why you would pick it | Oxygen resistance, low yellowing, water-clear films | Cheapest option, easiest to dose, good general-purpose workhorse | Deep cure, LED systems, photobleaching | TPO chemistry without the powder handling |
| What it costs you | Nothing, unless you need deep cure | Higher volatility, so more odour in the oven and more lamp fouling over time | Solid, slower to dissolve; see the Annex XIV note below | Tracks TPO's regulatory position |
Read that table as a set of trade-offs rather than a ranking. 1173 is the usual answer when someone wants to move off 184 cheaply, and it will cure your film. It will also smell more and foul your lamps sooner, which is a maintenance cost that does not show up on the raw material invoice. If odour is the constraint rather than cost, the calculus changes completely.
If your real driver is LED curing, then 184 was never the right product and the reclassification scare is a distraction. 184 absorbs to 330 nm. Standard 365 nm LED arrays will excite it, but 395 nm arrays largely will not. TPO and TPO-L both absorb past 370 nm and are the appropriate answer.
And a note on TPO itself, since people move to it for good reasons and then get a second scare. TPO was added to the REACH Candidate List in 2023, picked up a harmonised Repr. 1B classification applying from 1 September 2025, and was brought into Annex XVII by Commission Regulation (EU) 2025/1731. That entry restricts supply to the general public. Industrial formulation is not general public supply. The item to actually track is ECHA's November 2025 recommendation that TPO be added to the REACH Authorisation List, Annex XIV, which is a recommendation rather than law. We cover that in more detail on the TPO page. TPO-L was not included in that Annex XVII entry.
What we would do in your position
Three things, in this order.
Ask your current supplier for the latest SDS revision and check the classification section. If it says Repr. 1B, you have a stale document, and that is worth fixing for its own sake.
Write down the timeline. One paragraph in your regulatory file, with the IGM statement linked, saves a repeat conversation every time a customer audit asks the question.
Sample one alternative and cure it on your own line. A 100 g to 1 kg sample under your actual lamp tells you more than any comparison table, including this one. Cure speed, surface tack and colour are all system-dependent, and the interaction between photoinitiator, oligomer and pigment is not predictable from data sheets alone.
Checking the status yourself
We would rather you verified this than took our word for it. The primary sources are:
- IGM Resins' statement on the reclassification and its subsequent withdrawal
- The ECHA Candidate List, for SVHC status
- Annex XVII of REACH, consolidated text on EUR-Lex, for restrictions
- Annex VI of the CLP Regulation, for harmonised classifications
- Your supplier's SDS, Section 3 for classification and Section 14 for transport
If a supplier cannot produce a current SDS with a revision date, treat that as information about the supplier.
About our 184
We supply 184 as a white crystalline powder, 98% or better by GC, melting between 45 and 50 °C. Standard packaging is 20 kg cartons. Every batch ships with a COA, and the SDS is available in English on request. Samples for line trials are available.
We also supply the alternatives discussed above: 1173, TPO, TPO-L, 907, ITX and MBF. Tell us the substrate, the lamp and the destination market and we will tell you which one fits. If the honest answer is that none of ours does, we will say so.