Here is a concise, link-free checklist—in English—for thoroughly evaluating a Chinese surfactant supplier who claims to have “full REACH registration” for a surfactant.

1. Ask for Five Critical Documents  
1. POA (Power of Attorney) between the surfactant supplier and its EU Only Representative.  
2. REACH registration completion letter (shows registration number, tonnage band, registrant).  
3. REACH registration certificate (confirms the substance and the legal entity).  
4. Tonnage Coverage Certificate (TCC) explicitly covering your annual import volume.  
5. Up-to-date SDS and e-SDS in the official language of your EU destination country.

2. Verify Authenticity  
- **Registration number**: Search the ECHA Dissemination Portal using the registration number or CAS/EC number. Match the registrant name, tonnage band, and expiry date.  
- **Only Representative (OR)**: Cross-check the OR name against the official ECHA list of appointed ORs. Confirm the OR’s validity period.  
- **Consistency**: Ensure the registrant listed in the certificate matches the registrant shown in the portal; any mismatch is a red flag.

3. Confirm Tonnage Band  
- The registered tonnage band must be equal to or higher than your planned annual import volume.  
- The TCC must list either your company name or the EU importer’s name and the exact tonnage band.

4. Optional Third-Party Validation  
- Commission a compliance consultant or accredited laboratory to perform a document review (cost: roughly EUR 300–500 per substance).  
- For large volumes, arrange an on-site audit of the OR or the manufacturing site.

5. Ongoing Monitoring  
- Require the surfactant supplier to provide an updated SDS every six months and after every SVHC candidate list update.  
- Contractually oblige the surfactant supplier to maintain valid registration and to cover any costs arising from registration lapses.

Quick Reference  
1. Collect five documents.  
2. Verify registration number and OR in ECHA databases.  
3. Ensure tonnage band ≥ import volume.  
4. Secure TCC.  
5. Insert contractual safeguards.