If you import chemicals or chemical-containing products into Great Britain, your legal obligations under UK REACH changed fundamentally after Brexit. What was once a straightforward downstream user role under EU REACH is now an importer role with deferred registration duties, specific notification requirements, and ongoing compliance obligations that the Health and Safety Executive (HSE) actively enforces.
This guide covers what downstream users must do in 2026, including the Alternative Transitional Registration model (ATRm) reforms, updated SVHC Candidate List requirements, and the practical steps needed to remain compliant.
What Is a Downstream User Under UK REACH?
A downstream user under UK REACH is any business or individual that uses a substance — either on its own or in a mixture — in the course of industrial or professional activities. This includes importers who bring substances into Great Britain from outside the UK.
The critical change post-Brexit: if you were based in Great Britain and acted as a downstream user or distributor under EU REACH before 1 January 2021, you are now classified as an importer under UK REACH. Your registration obligation exists but has been deferred under transitional arrangements until the new deadlines take effect.
The 1-tonne-per-year threshold remains central. If you import or use less than 1 tonne per year of a substance, registration is not required. However, other obligations — including safety data sheet (SDS) compliance, authorisation restrictions, and SVHC notifications — still apply regardless of tonnage.
UK REACH applies in England, Scotland, and Wales. Northern Ireland continues to follow EU REACH under the Windsor Framework, creating a regulatory divergence that supply chain managers must navigate carefully.
Core Obligations for Downstream Users
Your duties as a downstream user fall into four main categories: chemical safety assessment, reporting, SDS management, and authorisation compliance.
Article 37: Chemical Safety Assessment
Under Article 37 of UK REACH, downstream users must identify and apply appropriate risk management measures. When you receive a safety data sheet from your supplier, it should include exposure scenarios that describe how the substance can be used safely.
Your obligations:
- Check coverage: Verify that your actual use conditions match the exposure scenarios provided. If your use is not covered, you must either notify your supplier, prepare your own chemical safety assessment (CSA), or rely on specific exemptions.
- Implement measures: Apply the risk management measures described in the exposure scenarios. This might include ventilation requirements, personal protective equipment, or engineering controls.
- Document decisions: Keep records of your assessments and the basis for relying on exemptions if applicable.
Article 38: Reporting Obligations
Article 38 requires downstream users to report to HSE in specific circumstances:
- When you prepare your own chemical safety report
- When you rely on exemptions from the chemical safety assessment requirement
- When proposed testing involves vertebrate animals
The report must include your business identity, substance details, supplier identity, and justification for any exemptions claimed. Failure to report when required is an enforcement priority for HSE.
Article 31: Safety Data Sheet Requirements
When you compile a safety data sheet for your own customers, you must include relevant exposure scenarios received from your suppliers. This creates a chain of information that flows through the supply chain.
Key requirements:
- Include all exposure scenarios applicable to your identified uses
- Ensure the SDS is in English and follows the UK REACH format
- Update the SDS when new information becomes available or when restrictions change
- Provide the SDS free of charge to downstream recipients
Article 66: Authorisation Notifications
If you use a substance on the UK REACH Authorisation List (Annex XIV), you must notify HSE within three months of first receiving the substance. The notification requires:
- Business name and address
- Site addresses where the substance is used
- Substance identity and tonnage
- Authorisation number (if your supplier holds one)
The Authorisation List carries over all substances that were on the EU list at 31 December 2020. Since then, the UK and EU lists have diverged independently.
DUIN and Transitional Registration
The Downstream User Import Notification (DUIN) was a one-time requirement for businesses that became importers under UK REACH. The deadline was 27 October 2021 — 300 days from the end of the transition period.
If you missed this deadline, late submissions are still accepted but should be made immediately. DUIN preserves your right to benefit from transitional registration deadlines rather than facing immediate full registration requirements.
Transitional Deadlines and the ATRm Reform
The original transitional registration deadlines under UK REACH were:
- 27 October 2026: Substances at 1,000+ tonnes per year; CMRs at 1+ tonne; very toxic to aquatic life at 100+ tonnes; substances on the Candidate List before 31 December 2023
- 27 October 2028: Substances at 100+ tonnes; substances added to the Candidate List between 1 January 2024 and 27 October 2026
- 27 October 2030: All other substances at 1+ tonne
However, the REACH (Amendment) (No. 2) Regulations 2026 — laid before Parliament on 24 March 2026 — selected Option 1 from the Alternative Transitional Registration model (ATRm) consultation. The new proposed deadlines are:
- 27 October 2029 (replacing 2026)
- 27 October 2030 (replacing 2028)
- 27 October 2031 (replacing 2030)
The ATRm aims to reduce the estimated £2 billion transition cost for the GB chemical industry by relying more heavily on existing assessments from EU REACH and other trusted jurisdictions where HSE considers them sufficient.
For downstream users, the ATRm does not change your immediate obligations. You still must:
- Submit DUIN if you haven’t already
- Comply with SDS, authorisation, and SVHC requirements
- Prepare for eventual registration under the new deadlines
- Maintain documentation proving your import volumes and use patterns
The “no data, no market” principle remains unchanged. Registration is not optional — substances without registration cannot be placed on the GB market after their deadline passes.
SVHCs and the Authorisation List
In 2026, HSE published the first independent update to the UK REACH Candidate List since Brexit. Fifteen substances of very high concern (SVHCs) were proposed for inclusion, and a registry of intentions now shows 26 entries as the UK begins systematic review of substances added to the EU Candidate List since 2021.
Why This Matters for Downstream Users
When a substance is added to the Candidate List:
- SDS updates: Your supplier must update the safety data sheet within 30 days
- Article 33 notifications: If your product contains more than 0.1% w/w of an SVHC, you must notify recipients and, on request, consumers
- Potential authorisation: Candidate List substances may be moved to the Authorisation List, requiring specific permission for continued use
The divergence between UK and EU SVHC lists is widening. As of mid-2026, the UK list includes substances that the EU has not yet classified, and vice versa. Supply chain managers must check both lists when trading across the Irish Sea or with EU customers.
Checking Your Portfolio
Practical steps:
- Request updated SDS from all chemical suppliers
- Screen products against both UK and EU Candidate Lists
- Document concentrations of any SVHCs present
- Prepare notification templates for customer inquiries under Article 33
- Monitor the Authorisation List for substances you use that may face sunset dates
Practical Compliance Steps for 2026
Based on the regulatory landscape and HSE enforcement priorities, here is what downstream users should do now:
1. Audit Your Chemical Portfolio
Create a complete inventory of all substances and mixtures you import or use. Include:
- Substance names and CAS numbers
- Annual tonnage bands
- Supplier details and their UK REACH status
- Current SDS revision dates
- Any known SVHC content
This audit forms the basis for all subsequent compliance work.
2. Verify DUIN Status
Check whether your business submitted a DUIN by the October 2021 deadline. If not, submit a late notification immediately through the HSE portal. Without DUIN, you lose access to transitional registration deadlines.
3. Review SDS Coverage
For each substance, verify that:
- The SDS is UK REACH-compliant (not EU REACH only)
- Exposure scenarios cover your actual use conditions
- The SDS is less than five years old (or updated when new information emerges)
- Article 33 SVHC declarations are present where applicable
Gaps here are common enforcement targets.
4. Assess Authorisation Status
Check the UK REACH Authorisation List for any substances you use. If present:
- Verify whether your supplier holds an authorisation covering your use
- If not, determine whether your use is exempt or requires your own authorisation
- Submit Article 66 notifications within three months of first receipt
- Plan for substitution if authorisation is unlikely to be granted
5. Prepare for ATRm Implementation
While the ATRm extends deadlines, it does not reduce data requirements. Begin gathering:
- Import volume records (to prove tonnage bands)
- Use descriptions (to match exposure scenarios)
- Supplier correspondence (to demonstrate supply chain engagement)
- Any existing EU REACH registration numbers (which may support ATRm reliance)
6. Maintain Documentation
HSE inspectors can request evidence of compliance at any time. Keep records of:
- Purchase invoices showing import volumes
- SDS versions and update history
- DUIN submission confirmations
- Article 66 notification references
- Risk assessments and CSA documentation
Common Pitfalls and Enforcement
HSE has broad enforcement powers under UK REACH, including improvement notices, prohibition notices, and unlimited fines for serious breaches. Common mistakes include:
Assuming ATRm means no action required: The ATRm extends deadlines but does not eliminate obligations. DUIN, SDS compliance, and SVHC duties remain unchanged.
Relying on EU REACH documentation alone: UK REACH is now independent. An EU-compliant SDS may not meet UK requirements, especially for SVHC declarations and exposure scenarios.
Missing Candidate List updates: The 2026 SVHC additions affect notification duties immediately. Subscribers to HSE updates or commercial regulatory services should verify their alerts are working.
Ignoring the 0.1% SVHC threshold: Article 33 obligations apply regardless of tonnage. A small amount of SVHC in an imported product still triggers notification duties.
Failing to update SDS when use changes: If your process changes and exposure conditions differ from the supplier’s scenarios, you must either notify the supplier or prepare your own assessment.
Key Takeaways
- Downstream users in GB are now importers under UK REACH with deferred registration duties but immediate compliance obligations
- DUIN notification was required by October 2021; late submissions should be made immediately to preserve transitional deadline access
- ATRm reforms extend registration deadlines to 2029, 2030, and 2031 but do not reduce SDS, SVHC, or authorisation requirements
- The UK SVHC Candidate List was updated in 2026 for the first time since Brexit — 15 new substances proposed, requiring immediate SDS and Article 33 compliance checks
- HSE actively enforces downstream user obligations — audits focus on SDS accuracy, exposure scenario coverage, and SVHC notifications
Frequently Asked Questions
Q: I import less than 1 tonne per year. Do UK REACH obligations still apply?
A: Yes. While registration is not required below 1 tonne, you must still comply with SDS requirements, SVHC notifications (Article 33), and authorisation restrictions for Annex XIV substances.
Q: My supplier provided an EU REACH safety data sheet. Is this sufficient for UK compliance?
A: Not necessarily. UK REACH is now independent from EU REACH. The SDS must reference UK regulations, include UK-specific SVHC declarations, and provide exposure scenarios valid for your GB operations. Request a UK-specific version from your supplier.
Q: I missed the DUIN deadline in 2021. Can I still submit?
A: Yes, late DUIN submissions are accepted. Submit immediately through the HSE portal to preserve your access to transitional registration deadlines. Without DUIN, you may face immediate full registration requirements.
Q: How do I know if a substance is on the UK SVHC Candidate List?
A: Check the HSE website’s UK REACH Candidate List page. The list was updated independently for the first time in 2026 with 15 new substance proposals. Also monitor the registry of intentions for upcoming additions.
Q: What happens if I use an Annex XIV substance without authorisation?
A: Using an Annex XIV substance after its sunset date without authorisation is illegal. HSE can issue prohibition notices, seize substances, and impose unlimited fines. Notify under Article 66 within three months of first receipt and verify whether your supplier’s authorisation covers your use.
Related reading: For broader UK REACH compliance context, see our UK REACH Compliance Guide. For import licensing requirements that may apply alongside REACH, consult our Import Export Licence Guide. If your substances are classified as dangerous goods, see our Dangerous Goods & Hazmat Shipping Guide.