Finding your co-registrants

You will need to share data and register your substance jointly with other companies. In practice, this means that you need to:

  1. Submit an inquiry via REACH-IT to ask ECHA if you have co-registrants. This will also alert your co-registrants of your interest to register;
  2. If you have co-registrants, agree with them that you have the same substance.

What’s next will mostly depend on whether your substance is already registered or not.

  • If other companies have registered your substance already, a joint submission will normally exist and you will need to join it.
  • If your substance is not registered, but other companies have also inquired, you and your co-registrants will need to agree how to work together to register jointly. If there are no co-registrants, you can start a joint submission on your own.

Finding your co-registrants starts with submitting an inquiry, but you can preview which substances are registered in ECHA’s database of registered substances.


If you plan to register, you have to inquire from ECHA whether there already is a registration for that substance.

An inquiry is prepared in IUCLID and submitted to ECHA via REACH-IT. 

Accurate identification of your substance in the inquiry is important to ensure that data will be shared appropriately.

If ECHA finds that the information in the inquiry is not sufficiently clear to establish the identity of the substance, you will be asked to improve your information.

If your inquiry is successful, you will get an inquiry number, and access to the co-registrants page for the substance in REACH-IT. In the co-registrants page, you will find the contact information of the other companies that have inquired or registered with the same substance identifier (e.g. EC number).

At the same time, your co-registrants will be alerted in REACH-IT that a newcomer was added to the co-registrants page.

Your access to the co-registrants page will expire if you do not register within one year. When you register, you have to include your inquiry number in your registration dossier.

Preparing to create or join a joint submission

The steps below explain how to go from a successful inquiry to preparing to create a new joint submission or join an existing joint submission. The actual creation or joining is explained in phase 6: submit your registration dossier.

If there are no co-registrants, you can prepare to create a joint submission on your own. Most of the steps below still apply.


1. Log into REACH-IT

REACH-IT is the IT tool you have to use for submitting information to ECHA, including inquiries and registrations.

You can access REACH-IT from ECHA’s homepage. You log in with your user ID and password. If you are not yet a user, you can sign up.


2. Access the co-registrants page

In REACH-IT, from the Search menu, click ‘Co-registrants’ to find the co-registrants page using your substance identifiers (e.g. EC number).

The ‘Registrants’ section will show the companies that have registered the substance, if any, with their contact details and role in the joint submission.

The ‘Potential registrants’ section shows the companies that have inquired for the substance but not yet registered, with their contact details. You will be listed here.


3. Verify your contact information in the co-registrants page

Since you need to register jointly, it is important that your contact information is up to date so that your co-registrants can reach you.

The contact information shown for you in the co-registrants page is the contact information specified in your inquiry, normally of a person in your company or a third party representative (TPR).

Decide if you want to keep the current contact in your inquiry or update it


4. Check if a joint submission exists

From the co-registrants page, click on the ‘Joint submissions’ button. On the ‘Joint submission search’ page you are brought to, check the box ‘Show other joint submissions?’. Otherwise, the search results will be limited to those joint submissions where you are already a member.

The search results will show you the existing joint submissions for the substance. If you did not inquire, the search will not retrieve any results.

If there is no joint submission, you should prepare for creating one with your co-registrants.

If a joint submission exists, verify if the type fits your registration:

  • if you will register a substance used as an intermediate that is (manufactured or) used under strictly controlled conditions, you can join either a ‘full’ (standard) joint submission or an ‘intermediate’ joint submission for your substance;
  • if you are planning a full registration, you can only join a ‘full’ joint submission. If only an ‘intermediate’ joint submission exists, you can agree with the existing joint submission that they will become a ‘full’ joint submission, or prepare to create a ‘full’ joint submission yourself.

Even if the substance has not been registered yet, it is possible that a joint submission has already been created by other (earlier) inquirers.


5. Contact your co-registrants and respond to their questions

If a joint submission needs to be created, contact your co-registrants with the contact information from the co-registrants page, to discuss further steps.

If you will join a joint submission, contact the lead registrant with the contact information from the ‘Joint submission search’ page.

Email is generally the easiest way to contact the co-registrants or the lead registrant. You cannot contact them through REACH-IT.

Respond to your co-registrants when they contact you about your registration intentions.


6. Establish substance sameness with your co-registrants

Once you are in contact with your co-registrants, you need to establish substance sameness.

For establishing substance sameness, all co-registrants – including yourself – need to have determined the name of their substance according to the Guidance for identification and naming of substances under REACH and CLP (see also phase 1: Know your portfolio).

If the name is the same, then the substances are considered the same.

If you have concerns about confidential business information (CBI) when discussing substance sameness, prepare for this contractually before starting the work.


7. Agree on the substance identification profile of the joint submission

Co-registrants preparing a joint registration should also collectively apply the principles of Appendix III of the Guidance for identification and naming of substances under REACH and CLP to define the boundaries of the substance corresponding to the data that they will submit jointly.

This is known as the substance identity profile (SIP) and will need to be reported in the lead registrant’s registration dossier.

In case you will join a joint submission, you will need to make sure that your substance is within the boundaries of the substance identity profile (SIP) agreed by the co-registrants. If your substance is not within the boundaries of the SIP, you and your co-registrants will need to agree either to expand the scope of the SIP or to agree that your substance is not within the scope of that joint submission.

Once you agree that your substances are the same, and that all co-registrants – including yourself – fit in the SIP of the joint submission, you can start working together to share data and costs to register jointly (see phase 3: Get organised with your co-registrants).


8. Become familiar with the roles and activities in a joint submission

There are two formally separate roles in the joint submission: the lead registrant and – if any – the member registrants. However, all co-registrants are responsible for the schedule and progress of the work, the content of the joint parts of the registration and the content of their own parts of the registration.

When creating a joint submission, the co-registrants will elect a lead registrant (see phase 3: Get organised with your co-registrants). The lead registrant will need to have the agreement of the co-registrants, and will have to submit the joint part of the registration through REACH-IT first, before the members can submit their registrations. The lead registrant also has to distribute the security token numbers to the members, so they can join the joint submission (see phase 6: Submit your registration dossier).

For all other tasks, you need to decide with your co-registrants on how you work together. In practice this means deciding on who does what and whether or not to outsource certain tasks. The agreement is usually documented.

The agreement should cover the different activities that the co-registrants have to perform to register (see phases 3, 4, 5 and 6) and keep the registration up to date (see phase 7). These include:

  • Administrative tasks: establishing contact points for communication, organising the way the invoices and payments are dealt with, developing reimbursement schemes and keeping records.
  • Preparing the content of the dossier: collecting existing data, generating new data, discussing data quality, agreeing what data will be submitted jointly, negotiating data-sharing costs, performing chemical safety assessments, deriving the classification, and preparing the chemical safety report.
  • Preparing the IUCLID dossier and submitting it: creating the joint part of the registration in IUCLID, submitting the dossier to ECHA and following up the invoice and messages in REACH-IT.

If you will be joining a joint submission, you will normally be a member registrant. The earlier co-registrants have already elected the lead registrant and decided on how to work together. This will usually be documented in an agreement. For further information on how to agree on sharing the data and submitting it jointly, see phase 3. The lead registrant will normally give you your security token number, so you can join the joint submission in REACH-IT.