1. What UV-326 is (in three lines)

UV-326 is a UV absorber whose chemical name is 2-tert-butyl-6-(5-chloro-2H-benzotriazol-2-yl)-4-methylphenol, also called bumetrizole, with EC number 223-445-4 and CAS number 3896-11-5. ECHA's support document gives its molecular formula as C₁₇H₁₈ClN₃O and its molecular weight as 315.8 g/molSourced.

• What it is used for: in the annex to its February 2026 announcement, ECHA gives example uses of UV-326 as an additive in plastics and rubber articles, coatings, adhesives and sealants, cleaning products, inks and fragrances, and puts the volume in the scope of authorisation at 1,000 to under 10,000 tonnes per yearSourced
• Where it stands now: under EU REACH it was identified as an SVHC (substance of very high concern) as vPvB (very persistent and very bioaccumulative) and added to the Candidate List on 23 January 2024Sourced. On 2 February 2026 a draft recommendation to put it on the Authorisation List was published, with comments invited until 2 May 2026Sourced. This stage is not yet a ban on use (Chapters 3 and 4)
• Treated differently from UV-328: what is in Annex A of the Stockholm Convention, in the EU POPs Regulation and among Japan's Class I Specified Chemical Substances is UV-328 and others; within the scope checked for this article, UV-326 is not in them (Chapters 5 and 6)

According to ECHA's support document, UV-326 has no harmonised classification in Annex VI to the CLP Regulation; classifications notified by companies themselves include aquatic hazards (H400, H411, H412, H413), skin irritation (H315), eye irritation (H319), respiratory irritation (H335) and dermal acute toxicity category 4 (H312) (classifications differ between notifiers)Sourced. The SVHC identification rests not on strong acute toxicity but on the property of resisting degradation in the environment and accumulating in organisms (vPvB) (Chapter 4).

2. What a UV absorber does

ECHA's support document places UV-326 in the group of phenolic benzotriazoles (UV-benzotriazoles), which share a 2-(2-hydroxyphenyl)-2H-benzotriazole core, and says that the intramolecular hydrogen bond between the hydroxy group and the nitrogen of the benzotriazole ring is essential for their function as UV absorbersSourced.

The risk management evaluation for UV-328 adopted in September 2022 by the Stockholm Convention's POPs Review Committee (POPRC) describes UV-328 as a UV absorber that can absorb the whole spectrum of UV light without being destroyed, used mainly to protect automotive paints, coatings, sealants, adhesives, plastics and rubbers from UV-induced degradation or color change. Typical use concentrations in plastics and coatings are 0.1 to 3% by weightSourced (a statement about UV-328, not a figure for UV-326).

The evaluation reports, as an industry association's explanation, that a UV absorber works inside the article (through its thickness) and protects against discoloration and loss of adhesion, that HALS protect against radical attack at the surface and so against chalking and blistering, and that HALS alone cannot replace a UV absorberSourced. A 2006 document from Japan's Ministry of Health, Labour and Welfare likewise says that UV-320 (another benzotriazole) was used mainly as a UV absorber for plastic resins, in products ranging from plastic building materials and auto parts to paints, at less than about 1% in each resinSourced.

3. Sorting out the regulatory stages

EU REACH has a sequence of SVHC identification, Candidate List, draft recommendation, recommendation, Commission decision (Annex XIV) and sunset date. ECHA's announcements describe it as follows.

All Sourced (ECHA announcement ECHA/NR/26/05 [Ref. 4], ECHA's Candidate List page [Ref. 1], ECHA's consultation page [Ref. 6], recitals of Delegated Regulation (EU) 2025/843 [Ref. 14]). The stage numbers are this article's.

4. Where UV-326 stands: EU REACH

(1) The history by date

All Sourced (Table 5 of the POPRC-18 evaluation [Ref. 13]; ECHA's support document [Ref. 3] and decision D(2023)8585-DC [Ref. 2]; Candidate List [Ref. 1]; announcement ECHA/NR/26/05 [Ref. 4]; consultation page [Ref. 6]; recommendations list [Ref. 7]). The last row marks what could not be confirmed.

(2) Why an SVHC: what “vPvB” consists of

ECHA's support document concludes, by a weight-of-evidence assessment against REACH Annex XIII, that UV-326 is vPvB (very persistent and very bioaccumulative)Sourced.

• Persistence (P/vP): in a water-sediment simulation study at 20 °C no degradation was observed after 100 days, and at 12 °C the half-life is estimated to be significantly larger than 212 days (DegT50 in sediment above 180 days). It also notes detections in sediment cores dating back decades (from the 1960s) as supporting informationSourced
• Bioaccumulation (B/vB): in an OECD TG 305 study with rainbow trout, the lipid-normalised, growth-corrected kinetic bioconcentration factor (BCFkgL) was 7,093 to 14,225 L/kg, which the document takes as above the criterion of 5,000 L/kg. It also cites monitoring results of detection in human breast milk and in biota including polar bearsSourced

vPvB is a category for substances that resist degradation in the environment and accumulate in organisms; it is not a category for how strong short-term toxicity is (Commentary; the definition is as explained by ECHA above). Together with the absence of a harmonised classification (Chapter 1), it would be wrong to read “SVHC” as “immediately dangerous”. Equally important, though, “SVHC” does not mean “no problem” either.

(3) What the draft recommendation says: uses shown by ECHA

In the annex to its February 2026 announcement, ECHA shows the uses and volumes of the four substances in the draft recommendationSourced.

Up to the “Example uses” column, Sourced (annex to ECHA's announcement [Ref. 5]). The parenthetical “appears to be a photoinitiator” is this article's reading and is not in the annex (Commentary).

Candidate List inclusion itself also carries obligations. ECHA's list page says that inclusion can bring companies immediate legal obligations, in particular under REACH Articles 7, 31 and 33Sourced (this article does not cover what each article requires). ECHA also says it will keep these lists up to date on the current pages until December 2026 and then move them to ECHA CHEMSourced, so links may change.

5. The path of UV-328: the Stockholm Convention and the EU

UV-328 is a substance of the same family as UV-326, but it has become a target of an international convention for elimination. Stages and dates are kept apart below.

All Sourced (ECHA's Candidate List [Ref. 1] and Authorisation List [Ref. 8]; Commission Regulation (EU) 2020/171 [Ref. 21]; the Stockholm Convention Secretariat's “New POPs” page [Ref. 9]; UN depositary notifications C.N.77.2024 [Ref. 10], C.N.97.2025 [Ref. 11] and C.N.542.2025 [Ref. 12]; Delegated Regulation (EU) 2025/843 [Ref. 14]). The “9 October 2026” in the last row is this article's calculation under the one-year rule of Article 22 of the Convention, not a confirmation of entry into force.

(1) Stockholm Convention SC-11/11: what was exempted

The text of decision SC-11/11 (annexed to the UN depositary notification) adds UV-328 to Part I of Annex A, providing that production is as allowed for Parties listed in the Register, and use follows a new Part XII. The exemptions for use are parts of motor vehicles (bumper systems, radiator grills, spoilers and the like), industrial coating applications for motor vehicles, engineering machines and rail vehicles and heavy-duty coatings for large steel structures, mechanical separators in blood collection tubes, triacetyl cellulose (TAC) film in polarizers, photographic paper and replacement parts for articlesSourced. The replacement-parts exemption applies only where UV-328 was originally used in making the article, until the end of the article's service life or 2044, whichever comes earlierSourced.

Decision SC-12/14 of COP-12 (2025) added to the use exemptions water-seal tape for insulation blankets and decking on aircraft, and polyurethane and polyamide adhesives and polyurethane coatings for structural, mechanical, interior and electrical assemblies, and for emergency, propulsion, environmental control and flight control systems, on aircraft (a summary of the text). It is limited to use only and in any case expires by the end of 2030Sourced. This is the first time adhesives are named in an exemption for UV-328 (Commentary; the SC-11/11 exemptions do not list adhesives).

(2) The EU POPs Regulation: trace-contaminant limits and exemptions

Delegated Regulation (EU) 2025/843 adds UV-328 to Part A of Annex I to the POPs Regulation (EU) 2019/1021. The main content is as followsSourced.

• Limit as an unintentional trace contaminant: in substances, mixtures or articles, 100 mg/kg (0.01% by weight) or less from 4 August 2025, 10 mg/kg (0.001%) or less from 4 August 2027, and 1 mg/kg (0.0001%) or less from 4 August 2029
• Exemptions for placing on the market of UV-328 present in articles, and use of those articles (until 4 August 2030): land-based motor vehicles; industrial coating for land-based motor vehicles, engineering machines and rail transportation vehicles, and heavy-duty coatings for large steel structures; mechanical separators in blood collection tubes; TAC film in polarisers; photographic paper; civilian and military aircraft
• Spare parts: for land-based motor vehicles, stationary industrial machines for agriculture, forestry and construction, and liquid crystal displays in analysis and measuring instruments, until the end of service life or 31 December 2043, whichever comes earlier; for liquid crystal displays in medical devices and so on, until the end of service life; for aircraft spare parts, until 31 December 2030
• Articles already in use: articles already in use in the EU on or before the expiry date of the relevant exemption may continue to be used afterwards

The recitals of the regulation confirm that Article 3 of the POPs Regulation prohibits the manufacture, placing on the market and use of substances listed in Annex I, whether on their own, in mixtures or in articles. The five-year duration of the exemptions on placing on the market is explained as allowing the import of certain articles containing UV-328 until the substance is fully substitutedSourced.

6. Japan's CSCL: UV-320, UV-328 and UV-326

Japan's Chemical Substances Control Law (CSCL; the Act on the Evaluation of Chemical Substances and Regulation of Their Manufacture, etc.) designates chemicals that are persistent, highly bioaccumulative and of long-term toxicity to humans or higher predators as Class I Specified Chemical Substances. Once designated, manufacture and import require a licence (in effect prohibited), use is restricted, and import of products designated by cabinet order is prohibited (as stated by METI)Sourced.

All Sourced (METI announcement [Ref. 15], MOE announcements [Refs. 16, 17], MHLW's 2006 announcement [Ref. 18], the CSCL Enforcement Order on e-Gov [Ref. 19]). The promulgation and effective dates of the order designating UV-320 could not be confirmed here.

7. Our calculation: intervals between stages, and trace-contaminant limits

8. A materials engineer's view 1: the same substance is regulated in different ways

The entries are Sourced (recitals and annex of Delegated Regulation (EU) 2025/843 [Ref. 14], METI announcement [Ref. 15], e-Gov [Ref. 19]). “Use of mixtures containing the substance is also covered” is this article's description of how REACH authorisation generally works (Commentary), not a check of any individual Annex XIV entry. This table concerns substances whose frameworks are settled, such as UV-328. These frameworks do not currently apply to UV-326.

Three practical readings follow (Commentary).

• Making something in the EU and bringing it into the EU are different. REACH authorisation does not stop imports of articles, but the POPs Regulation covers articles too. Because UV-328 is in both, an article import that authorisation does not stop can still be stopped by the POPs Regulation
• Even if you think you do not use it, there are trace limits. Impurities in raw materials, recycled material and spare parts can contain it (the stepped limits are in Chapter 5)
• Japan stops it at product import. If you import finished adhesives, tapes or sealants, you need to ask the raw-material supplier whether the formulation contains the substance. According to the POPRC evaluation, members of the Swiss adhesives industry association that responded to a survey said they do not intentionally add UV-328 to adhesivesSourced (though the evaluation adds that UV-328 was not analysed in their raw materials or products)

9. Alternatives: what official material shows

The POPRC-18 risk management evaluation sets out alternatives to UV-328 in the most detail. The main points are as followsSourced.

• Classes of alternatives: alternatives widely available for UV-328 are other phenolic benzotriazoles, benzophenones, HALS, oxalanilides and cyanoacrylates. The evaluation says safer alternatives for the most relevant applications seem technically feasible and accessible
• A warning against “regrettable substitution”: it cautions that replacing UV-328 with other phenolic benzotriazoles can be a regrettable substitution, since several could be as harmful as UV-328. It records that, at that time (2022), several including UV-326 were under PBT assessment in the EU, and that the German authority had a tentative plan to propose UV-326, UV-234 and UV-329 as SVHCs in 2023. It also records that a hazard assessment by a company in 2018 had counted UV-326 among “safer alternatives”. UV-326 and UV-329 were then added to the Candidate List in January 2024 (Chapter 4)
• Performance of alternatives: HALS are not UV absorbers, and HALS alone cannot replace a UV absorber. Benzophenones are said by a producer of UV-328 to absorb over a narrower range, with weak absorption beyond 370 nm. The hydroxyphenyl-triazine (HPT) class, such as UV-400, is said to have advantages over benzotriazoles in photo performance, heat stability and chemical resistance. A reactive absorber (UV-1300) has a hydroxyl group that bonds covalently to isocyanates and melamine, which can reduce migration and leaching, but the evaluation notes there are no data on persistence, bioaccumulation or toxicity
• Adhesives and sealants: the evaluation says no specific information on substituting UV-328 in adhesives and sealants could be identified. It does record that the Swiss adhesives association's answer suggests effective alternatives are available for adhesives, that one company is in the process of replacing UV-328 with UV-928, and that several examples of absorbers and HALS usable in adhesives and sealants exist. However, the evaluation's own table lists UV-928 as under PBT assessment

10. A materials engineer's view 2: alternatives cannot be chosen on the same footing

11. What could not be confirmed

(1) UV-326's next procedural steps

The MSC opinion, ECHA's final recommendation and the Commission's decision on the 13th draft recommendation are not shown on the official pages that could be checked (the recommendations list was updated on 15 May 2026) and could not be confirmed. Whether UV-326 will be listed in Annex XIV, and what sunset date or exemptions would apply, cannot be read from the material availableNot yet confirmed.

(2) UV-326 in other countries and other frameworks

What this article checked is EU REACH, the Stockholm Convention, the EU POPs Regulation and Japan's Class I Specified Chemical Substances. The treatment of UV-326 under rules in the United States, Canada, China, South Korea, the United Kingdom and elsewhere, other Japanese categories (monitoring and priority assessment chemical substances and so on) and other EU frameworks (restrictions and so on) has not been confirmed.

(3) Whether a particular product contains UV-326

Whether an individual adhesive, encapsulant or coating contains UV-326 depends on the maker's safety data sheet (SDS) and declarations. This article did not check the formulation of any particular product.

(4) A quantitative comparison of alternatives

No quantitative comparison of weather resistance (yellowing, retention of adhesion) between UV-326 or UV-328 and alternative absorbers could be confirmed in official material. The POPRC evaluation relays company reports (for example, that 5 of 25 formulations met expectations for weathering), but these are companies' own reports, with conditions not disclosed. Primary sources on how UV absorbers are used in UV-curing adhesives and coatings could not be confirmed either.

(5) UV-326's absorption spectrum

Figures for UV-326's absorption range (such as the absorption maximum) could not be confirmed in the official material consulted. The effect of an absorber on UV curing therefore cannot be given in numbers.

12. Glossary

13. References

1. ECHA (European Chemicals Agency) “Candidate List of substances of very high concern for Authorisation” (checked 3 October 2026) — echa.europa.eu
2. ECHA “Inclusion of substances of very high concern in the Candidate List for eventual inclusion in Annex XIV” (decision D(2023)8585-DC, 19 December 2023) (PDF) — echa.europa.eu
3. ECHA (Member State Committee) “Support document for identification of Bumetrizole (UV-326) as a substance of very high concern because of its vPvB properties” (adopted 13 December 2023) (PDF) — echa.europa.eu
4. ECHA “ECHA consults on recommending four substances for REACH authorisation” (ECHA/NR/26/05, 2 February 2026) — echa.europa.eu
5. ECHA “List of substances proposed for inclusion in the 13th draft recommendation with examples of uses of the substance” (annex to the announcement) (PDF) — echa.europa.eu
6. ECHA “Consultation on draft recommendation for inclusion in the Authorisation List” (consultation page) — echa.europa.eu
7. ECHA “Recommendations for inclusion in the Authorisation List” (list of recommendations, updated 15 May 2026) — echa.europa.eu
8. ECHA “Authorisation List” (Annex XIV) — echa.europa.eu
9. Stockholm Convention Secretariat “The new POPs under the Stockholm Convention” — chm.pops.int
10. United Nations (depositary) Depositary Notification C.N.77.2024.TREATIES-XXVII.15, “Amendments to Annex A” (26 February 2024; includes the texts of decisions SC-11/9, SC-11/10 and SC-11/11) (PDF) — treaties.un.org
11. United Nations (depositary) Depositary Notification C.N.97.2025.TREATIES-XXVII.15 (reissued 26 February 2025; the European Union's notification of non-acceptance) (PDF) — treaties.un.org
12. United Nations (depositary) Depositary Notification C.N.542.2025.TREATIES-XXVII.15, “Amendments to Annex A” (9 October 2025; includes the text of decision SC-12/14) (PDF) — treaties.un.org
13. Stockholm Convention POPs Review Committee UNEP/POPS/POPRC.18/11/Add.2 “Risk management evaluation for UV-328” (eighteenth meeting, September 2022; dated 15 March 2023) (PDF) — chm.pops.int
14. European Commission Commission Delegated Regulation (EU) 2025/843 of 5 May 2025 amending Annex I to Regulation (EU) 2019/1021 as regards UV-328 (Official Journal, 15 July 2025) — eur-lex.europa.eu
15. Ministry of Economy, Trade and Industry (METI), Japan Announcement that the Cabinet Order partially amending the Order for Enforcement of the CSCL was approved by the Cabinet (13 December 2024) (in Japanese) — meti.go.jp
16. Ministry of the Environment (MOE), Japan Announcement on the Cabinet approval of the Cabinet Order partially amending the Order for Enforcement of the CSCL (13 December 2024) (in Japanese) — env.go.jp
17. Ministry of the Environment (MOE), Japan Announcement on the first and second reports of the Central Environment Council (1 August 2024) (in Japanese) — env.go.jp
18. Ministry of Health, Labour and Welfare (MHLW), Japan Announcement of deliberation results on a chemical substance corresponding to a Class I Specified Chemical Substance under the CSCL (11 July 2006) (in Japanese) — mhlw.go.jp
19. e-Gov Law Search (Digital Agency, Japan) Order for Enforcement of the Act on the Evaluation of Chemical Substances and Regulation of Their Manufacture, etc. (Cabinet Order No. 202 of 1974): text and amendment history (retrieved 3 October 2026) (in Japanese) — laws.e-gov.go.jp
20. Henkel Corporation “Light Cure Adhesive Technology Guide” (10731/LT-2013, September 2013) (PDF) — dm.henkel-dam.com
21. European Commission Commission Regulation (EU) 2020/171 of 6 February 2020 amending Annex XIV to Regulation (EC) No 1907/2006 (Official Journal, 7 February 2020) — eur-lex.europa.eu

14. Claim-to-source audit

Last updated 3 October 2026 (checking date). Sources are limited to official material from the European Chemicals Agency (ECHA), the United Nations (depositary notifications), the Stockholm Convention Secretariat, the EU Official Journal (EUR-Lex), Japan's METI, MOE and MHLW, and e-Gov law search. Because regulation changes, please check the authorities' official pages for the latest status. This article is not legal advice and does not recommend or criticize any substance, product or company. Because it includes structural readings and materials-design interpretations, those are marked as Commentary and kept separate from sourced fact. Procedures after the draft recommendation for UV-326, rules in other countries, the formulation of individual products, a quantitative comparison of alternatives, how absorbers are used in UV-curing systems and UV-326's absorption spectrum could not be confirmed and are not stated here. All figures are explanatory. Figs. 1, 2 and 3 are vector drawings, Fig. 4 is a vector drawing that includes our own calculations, and the hero image and Fig. 5 are AI-generated images; none of them shows a real instrument, product or test result.