IUCLID 6 Uses

You build the dossier in IUCLID, then upload it through the REACH-IT submission wizard, which takes you through each step. After that, ECHA runs its checks, sends you the fee invoice and gives you a registration number. Before any of this, you send an inquiry if the law requires one, and you join the joint submission for your substance ^[7][8].

Approach: I used the consolidated REACH Regulation (EC) No 1907/2006 and the REACH guidance from Ireland's HSA and Spain's Ministry of Health. ECHA's own REACH-IT manuals, with their screen-by-screen instructions, are not in the datasets I can search.

1. Before the dossier: inquiry and joint submission

• When an inquiry is needed. Under Article 26, you must ask ECHA whether the substance is already registered if it is a non-phase-in substance, or a phase-in substance you did not pre-register. The inquiry must include:
  • your identity;
  • the substance identity;
  • which information requirements would need new vertebrate studies, and which would need other new studies ^[9].
• How the inquiry works. HSA says the inquiry dossier goes in through REACH-IT, and you should wait for the result before registering or starting tests on vertebrate animals. If a registration already exists, ECHA sends you to the Co-Registrants page in REACH-IT. You and the other registrants are responsible for confirming that it is the same substance ^[7].
• Joint submission (Article 11). The lead registrant submits first, with the other registrants' agreement. That shared part covers classification and labelling, study summaries, robust study summaries and testing proposals. Each member then submits separately its own:
  • company identity;
  • substance identity;
  • manufacture and use information;
  • exposure information for 1-10 t substances.
• Opting out of shared data. You can submit some shared data separately, but only on grounds of disproportionate cost, commercial sensitivity, or disagreement with the lead registrant, and you must explain why with the dossier ^[10].
• Your own registration. HSA notes it is one registration per legal entity. Your dossier carries your tonnage and uses and refers to the lead dossier where relevant ^[7].

2. Prepare the dossier in IUCLID

• Article 111 makes IUCLID the required format for the Article 10(a) technical dossier ^[8].
• The data you need depends on your tonnage band (Annexes VII-X). A chemical safety report (CSR) is needed only above 10 tonnes a year ^[7].
• Spain's ministry adds that the CSR must stand on its own, separate from the data in IUCLID ^[4].

3. Pre-submission checklist (HSA)

• The information in REACH-IT is up to date and the company contact details are correct.
• The right company size is selected, because it sets the registration fee.
• The dossier has been run through the IUCLID Validation Assistant.
• You have the correct IUCLID file saved on your computer.

Source for this list: ^[7].

4. Submit through the REACH-IT wizard

• Once the IUCLID file is ready, you upload it in REACH-IT and the submission wizard guides you step by step ^[7].
• Spain's ministry describes REACH-IT as the web portal companies use to submit registration dossiers ^[1].
• Confidentiality claims. Before you submit, you can ask for certain data to be kept confidential and see what will be published. ECHA assesses every claim, and some carry a fee ^[7].

5. After submission

• Submission number and date. ECHA gives you a submission number to use in all correspondence until the registration is complete. The submission date is the date ECHA receives the dossier (Art. 20(1)) ^[11].
• Business rules check. This only confirms the dossier is accepted for processing. If it fails, you correct the dossier and resubmit ^[7].
• Completeness check (Art. 20(2)).
  • ECHA checks that the elements required under Articles 10 and 12 are there and that the fee has been paid. It does not judge data quality or adequacy.
  • The deadline is three weeks from the submission date. The Article also sets a three-month window, tied to the old phase-in registration deadlines.
  • If the dossier is incomplete, ECHA sets a deadline to complete it. If you miss that deadline, the registration is rejected and the fee is not refunded ^[11].
  • HSA adds that you get only one more submission attempt ^[7].
• Invoice. It arrives in REACH-IT while the completeness check runs. A second completeness failure, or not paying, means rejection ^[7].
• Registration number. Once the dossier is complete, ECHA assigns the registration number, and the registration date is the same as the submission date (Art. 20(3)). ECHA also tells the competent authority of the relevant Member State within 30 days (Art. 20(4)) ^[11].
• Appeals. You can appeal completeness-check decisions under Articles 91-93 (Art. 20(5)) ^[11].

6. Keeping the dossier up to date

• You must update the dossier when the composition changes, your tonnage moves into a higher band, or new information comes up (for example on classification, or after a substance evaluation). Some updates carry a fee ^[7].
• ECHA publishes data from the dossier on ECHA CHEM ^[7].

I can also set out the REACH fee structure, or the Article 22 update triggers, next if that would help.

You can see part of other companies' dossiers, not the whole thing. ECHA publishes a set list of information from every registration free on ECHA CHEM, and some more unless the registrant has had a confidentiality claim accepted. You can also ask ECHA for documents under the EU access-to-documents rules. Two limits matter:

• Confidential business details are normally withheld.
• Reading published data does not let you use it in your own dossier. For that you need a letter of access or a data-sharing agreement.

Approach: I used the consolidated REACH Regulation (EC) No 1907/2006, Article 42 of CLP, and the Irish HSA's REACH registration guidance. ECHA's own dissemination and access-to-documents pages are not in the datasets I can search.

1. Always published (Article 119(1)) Free on the internet, whatever the registrant asks ^[12]:

• the IUPAC name, for substances that meet certain CLP hazard classes;
• the EINECS name;
• classification and labelling;
• physicochemical, pathway and environmental fate data;
• the result of each toxicological and ecotoxicological study;
• DNELs and PNECs;
• guidance on safe use;
• analytical methods, where Annexes IX or X required them.

The HSA confirms that ECHA puts this on ECHA CHEM. ECHA CHEM also shows which substances are already registered ^[7].

2. Published unless an accepted confidentiality claim keeps it back (Article 119(2)) The registrant has to request this in the dossier under Article 10(a)(xi), with a justification of the commercial harm, and ECHA has to accept it ^[13][12]. The items covered are:

• purity, and the dangerous impurities or additives, where they matter for classification;
• the total tonnage band;
• the study summaries and robust study summaries;
• other information from the safety data sheet;
• trade names;
• in certain cases, the IUPAC name. If that is kept back, the registrant must give a public name instead ^[7].

3. Asking ECHA for documents (Article 118)

• Regulation (EC) No 1049/2001 on public access to documents applies to documents ECHA holds.
• Disclosure of the following is "normally deemed" to harm the company's commercial interests, so expect these to be withheld:
  • the full composition of a mixture;
  • the precise use, function or application;
  • the precise tonnage;
  • links between a manufacturer or importer and its distributors or downstream users.
• ECHA may disclose them anyway where urgent action is needed to protect health, safety or the environment.
• If ECHA refuses, you can complain to the Ombudsman or bring an action before the Court of Justice ^[14].
• The same rules govern the C&L Inventory under CLP Article 42. The public part matches Article 119(1). The rest is open to the notifiers and registrants of that substance, and to others only under Article 118 ^[15].
• From 1 July 2026, notifier names on the C&L Inventory are public unless a confidentiality claim is justified ^[16].

4. If you are registering the same substance: data sharing, not open access

• Inquiry. If the substance was registered less than 12 years earlier, ECHA gives you the names and addresses of the earlier registrants and the relevant (robust) study summaries they submitted (Art. 26(3)) ^[9].
• Co-registrants in REACH-IT. The HSA says REACH-IT then sends you to the Co-Registrants page, which has contact details for the other registrants ^[7].
• Getting the full study reports.
  • You get them by agreement with the earlier registrants, at a fair, transparent and non-discriminatory cost (Art. 27).
  • For vertebrate studies you must ask for them; for other studies you may.
  • If you cannot agree, ECHA can give you permission to refer to the data once you show you have paid a share of the cost (Art. 27(6)) ^[17].
  • Inside a SIEF, Article 30 sets similar rules, including what happens if a study owner refuses to share ^[18].
• Seeing data is not the right to use it. You must legally hold the full study reports you summarise, or have permission to refer to them. The only exceptions are Article 25(3), 27(6) and 30(3) ^[13].
• The 12-year rule. Under Article 25(3), study summaries submitted at least 12 years ago can be used by another registrant ^[19].
• No market information. Data sharing covers technical data. Registrants must not exchange production, sales or import volumes, or market shares (Art. 25(2)) ^[19].
• Costs and disputes. Implementing Regulation (EU) 2016/9 governs how costs are shared, and ECHA can step in on data access as a last resort ^[7].

If it helps, I can look up what is disseminated for a specific substance, or set out the data-sharing dispute procedure under Implementing Regulation 2016/9.