This report covers UK REACH dossier and substance evaluation activity undertaken by HSE as the Agency for UK REACH, supported by the Environment Agency for the assessment of environmental information.
Dossier evaluation
Dossier evaluation in UK REACH includes 2 activities: the assessment of Annex 9 or Annex 10 testing proposals submitted by registrants and compliance checking of registration dossiers. These activities are described under Article 40 and 41 of UK REACH, respectively.
A registrant who intends to generate information to meet any of the requirements set out in Annexes 9 or 10 must submit a testing proposal to HSE. In line with UK REACH Article 40, HSE, supported by the Environment Agency, examines all testing proposals to ensure that they address information needs and avoid unnecessary testing that would involve the use of vertebrates.
The registrant may only proceed with testing when HSE has issued a formal decision to request the proposed test, a modification of the proposed test, or a different test. The test(s) proposed by a registrant can also be rejected entirely.
HSE, supported by the Environment Agency, may examine a registration dossier at any time to verify that the information submitted by registrants is compliant with the legal requirements. This includes consideration of whether adaptations of standard information requirements in Annexes 7 to 10 comply with the rules laid out in the respective annexes or Annex 11. The standard information requirements are cumulative and depend on the tonnage band.
Compliance checks
Most of the registration dossiers submitted up to 31 December 2024 contain little data owing to the transitional provisions for data submission that continued to apply to grandfathered registrations and downstream user import notifications. Therefore, our compliance checks focused on dossiers relating to ‘novel’ substances, such as those that were not registered under EU REACH prior to 1 January 2021. These are not subject to the transitional arrangements described above.
Between 1 January 2021 and 31 December 2024, we received dossiers relating to 82 registrations of novel substances. By the end of 2024, compliance checks had been completed on dossiers supporting 38 (46%) of those registrations, 6 were concluded with decisions requesting further data and 32 were concluded without the need for further data – see Table 1 below.
Table 1: Number of novel substance registrations for which HSE completed compliance checks, 2021-2024
| Tonnage band (per annum) | Novel substance registrations | Checks completed | Concluded without further data requests | Concluded with further data requests | % of registrations checked |
|---|---|---|---|---|---|
| ≥ 1,000 | 5 | 1 | 1 | 0 | 20% |
| 100 – 1,000 | 4 | 2 | 2 | 0 | 50% |
| 10 – 100 | 15 | 3 | 3 | 0 | 20% |
| 1 – 10 | 58 | 32 | 26 | 6 | 55% |
| Total | 82 | 38 | 32 | 6 | 46% |
Across the 6 compliance checks that were concluded with decisions, a total of 36 requests were made:
- physicochemical - 16 requests
- toxicological – 10 requests
- ecotoxicological – 10 requests
These included requests for information relating to: skin corrosion/irritation (1 request), serious eye damage/eye irritation (2), skin sensitisation (3), mutagenicity (2), acute toxicity (2), short-term toxicity testing on invertebrates (3), growth inhibition of aquatic plants (3) and ready biodegradability (4).
No compliance-related requests were made for new vertebrate data in the first instance. All requests for toxicological information required registrants to apply alternative approaches. Examples of requested alternative approaches included weight of evidence, read-across, computational predictions, in vitro methods and defined approaches. Where requests were made for tests on animals, these were to be conducted only if the registrants were not able to use the stated alternatives. There were no requests for vertebrate data to meet ecotoxicological information requirements.
Testing proposal evaluations
In 2024, HSE received testing proposals for 2 substances, both relating to toxicological and ecotoxicological information requirements. The toxicology proposals were the subject of public consultations to establish if data already existed that could fulfil each information requirement. This was because the studies proposed would involve testing on vertebrates. HSE did not receive any responses to the consultations.
The toxicological testing proposed by the registrants was in line with the relevant standard information requirements for the registrations. However, HSE identified that there was potential to use a read-across approach in place of some testing. HSE requested this be investigated first to reduce the number of vertebrate tests conducted.
The registrant’s proposal for the ecotoxicological testing supported the principles of the 3Rs (Replacement, Reduction and Refinement). The registrants proposed non-vertebrate testing be undertaken initially, which, depending on the outcome and updated chemical safety assessment, could mean that vertebrate tests would not be needed to meet ecotoxicological information requirements.
Consequently, HSE adopted 2 decisions relating to these proposals that supported the 3Rs. For details, please see Table 2.
Table 2: Testing proposal decisions adopted in 2024
| Substance | Testing proposed | Testing requested |
|---|---|---|
N-[3-({[2,2-dimethyl-3-(morpholin-4-yl)propylidene]amino}methyl)-3,5,5-trimethylcyclohexyl]-2,2-dimethyl-3-(morpholin-4-yl)propan-1-imine CAS: 1217271-02-7 |
Chronic invertebrate study (OECD TG 211) Sub-chronic repeated-dose toxicity study in rats (OECD TG 408) Pre-natal developmental toxicity study in rats (OECD TG 414) |
Chronic invertebrate study (OECD TG 211) Modification supporting 3Rs Consider read-across options to meet human health information requirements before testing is conducted Deadline to submit information: 19th November 2026 |
Reaction product of propylidynetrimethanol, propoxylated, reaction products with ammonia and 2,2-Dimethyl-3-(4-morpholinyl)propanal CAS: 1379822-00-0 |
Chronic invertebrate study (OECD TG 211) Sub-chronic repeated dose toxicity study in rats (OECD TG 408) Pre-natal developmental toxicity study in rats (OECD TG 414) |
Chronic invertebrate study (OECD TG 211) Modification supporting 3Rs Consider read-across options to meet human health information requirements before testing is conducted Deadline to submit information: 19th November 2026 |
In 2024, HSE received information to address a request in a testing proposal decision adopted in 2022 (see Table 3). The standard information requirement at Annex 8 for mutagenicity is two separate animal tests. However, HSE accepted the registrant’s proposal to use a combined test thus reducing the number of animals used.
Table 3: Information received in 2024 to address testing proposal decisions
| Substance | Testing requested | Assessment |
|---|---|---|
1-(4-(acetyloxy)-3-((acetyloxy)methyl)phenyl)ethanone CAS: 24085-06-1 |
Mammalian Erythrocyte Micronucleus Test (OECD TG 474) combined with an in vivo Mammalian Alkaline Comet Assay (OECD TG 489) |
The registrant submitted two robust study summaries; one for each aspect of the combined test (OECD TG 474 and OECD TG 489) The information met the requirements of the decision |