You may, for example, choose to send emails or create a separate discussion forum on joint submission issues.

You and your co-registrants need to agree on how to work together. This is the basis for all cooperation and impacts your individual tasks and responsibilities. Make sure that the agreement with your co-registrants also deals with requests to share data with newcomers, and requests to provide additional data during substance or dossier evaluation.

Estimate the workload and decide how to share the work: it can be shared equally, or you can agree that one co-registrant or a smaller group of co-registrants take a more prominent role. You can also agree to hire a consultant to assist you in preparing the joint submission. Have a look at the Checklist to hire a consultant on ECHA's website. Combined approaches are also possible.

Some industry associations host dedicated REACH groups or consortia for substances, which could be related or similar to yours. They may be willing to add your substance to the scope of their existing registrations or provide an opportunity for the data to be read across. The contact details of the industry associations that are ECHA's accredited stakeholder organisations are available on ECHA's website.

If you agree that one co-registrant takes a more prominent role or that you will appoint a consultant, this work should typically be compensated by the other co-registrants. You need to agree on how to organise invoicing and payments for these costs. This is different from sharing the costs of data.

All co-registrants are also responsible for the content of the joint parts of the registration as well as the content of their own parts of the registration. However, you need to agree that one of you takes the role of the lead registrant. In practice, the formal appointment of the lead registrant can happen after the dossier has been prepared, but the sooner you agree on this, the better.

The lead registrant is responsible for submitting the lead dossier into the joint submission first, with the agreement of the co-registrants. The other co-registrants then become member registrants of the joint submission when they submit their registration. Keep in mind that preparing the registration dossier and managing other tasks in the joint submission are shared responsibilities for all co-registrants. These tasks can either be shared between the members or outsourced.

How does the lead registrant fulfil this duty in practice?

The lead registrant needs to:

• create a joint submission in REACH-IT;
• submit the joint part of the registration (lead dossier); and
• distribute the security token to members so they can join the joint registration by submitting their own dossier (member dossier).

In other words, members do not submit a full dossier, but refer to the information included in the lead dossier in their registration.

There are several ways to select a lead registrant. It may be that one company has more interest in registering the substance than the others and volunteers. You may also choose the co-registrant who has most of the data on the substance already available or one who has most information requirements to fulfil. You can even try a lottery if no other means work.

In any case, you will need to come to an agreement with the co-registrants. ECHA will not be able to assist you on agreeing on who will be the lead registrant.

To find out which data is available among the co-registrants, you can survey them all. For example, the data exchange form that can be found in Annex I to the Guidance on data sharing can be used to do this.

Next, one of you or an external expert could conduct an in-depth literature search to identify data available outside your group.

To find support for your potential read-across strategy, you may consult ECHA's website (Search for chemicals) on already registered substances, as well as the Global Portal to Information on Chemical Substances hosted by the OECD (eChemPortal).

When you plan to use existing data for your registration, you will always need to consider intellectual property rights.

Based on this information, you can develop an inventory of all available data and their copyright status.

Learn more about the information requirements that apply to the tonnage band of the substance you manufacture or import, and the type of registration (full or intermediate) you need on the page "Information requirements".

Assess the relevance, reliability and adequacy of the available data to see that it is fit for purpose. You need to have a complete dataset that satisfies the information requirements you need for your registration. It may also be that the co-registrants own several studies that cover the same information requirement. All relevant data should be submitted in the registration.

Compare the data you have to the information requirements and make an inventory of the data that is missing for a complete registration.

Keep in mind that performing tests on animals is the last resort to fill in a data gap – all alternative methods need to be considered first. You will also have to be able to show that you have done that.

Agree with your co-registrants how to proceed to fill in data gaps: for example, whether an alternative to testing could be used (e.g. read-across or QSAR), if not, what tests to conduct, which laboratory to use and who will be in charge of obtaining the information.

If you need to use data which is not owned by a co-registrant, you need an agreement from the data owner. This agreement may be a specific Letter of Access (LoA) or a Licence to Use. Note that this agreement is separate from the data-sharing agreement among the co-registrants.

It is recommended that such an agreement is valid for all co-registrants including future ones. This would allow co-registrants to use the data without having to individually negotiate access to it.

Each individual study comes with a price. This price can consist of the costs for performing a test, costs for buying access to required data or costs of satisfying your information requirement with a non-testing method. If there are no invoices available for an item, the costs for performing the test again can give an indication of the value of the test.

Besides the cost of data itself, non-study costs will also need to be shared. These can relate to:

• a specific study (e.g. the costs for administering the contract with a laboratory to conduct a new test or a contract with an external data holder to get access to an existing study)
• the technical dossier preparation (inserting information into the IUCLID dossier)
• the administration of the joint submission (preparation of the joint submission, distribution of security token to the members, post-registration communication, managing the reimbursement scheme)

The division of costs as study costs or non-study costs may vary across joint submissions, depending on how the responsibilities and tasks were allocated. For example:

• the administrative costs related to a laboratory test may be considered as part of the study costs in some cases and would not appear in the non-study costs;
• depending on the cooperation model of the co-registrants, the costs related to the preparation of the joint submission (before submission of the dossier) and joint submission management (moment of registration and period after the registration) may not be separated.

No matter what the costs are called or how they are allocated, it is important that they are recorded transparently.

You can also consider agreeing on:

• Chemical safety report (CSR): for registrations above 10 tonnes per year, you need to submit a chemical safety report in addition to a IUCLID dossier. You can prepare it jointly with your co-registrants or by yourself. If you decide to prepare your own CSR, you should not pay costs related to the preparation of your co-registrants' CSR. For registrations between 1-10 tonnes per year, a CSR is not required.
• Guidance on safe use of the substance: as a CSR is not needed for registrations between 1-10 tonnes per year, you will need to submit more information in the guidance on safe use section of your registration dossier. You may consider sharing the costs of preparing the guidance on safe use jointly with your co-registrants.

Study and non-study costs need to be shared in a fair, transparent and non-discriminatory manner.

There are several models on how to determine the value of data for REACH purposes. The basis is always the actual cost of data, while the decrements or increments applied to that cost need to be agreed among the co-registrants.

Remember that you only need to pay for the studies you need for your registration. Your needs depend on your registration type (standard or intermediate) and tonnage band (1-10 or 10-100 tonnes per year). Your co-registrants might not have the same information requirements as you.

The Cost sharing chapter of the Guidance on data sharing provides more information on study valuations for REACH registration. For more summarised information, have a look at the factsheet Typical cost elements in data-sharing negotiations.

Agree on a cost-sharing mechanism that is fair, transparent and non-discriminatory to potential future co-registrants. They will have to contribute to the costs of the joint registration but will also have a right to challenge your original choices if something is not clear.

Be prepared to answer the questions of newcomers, justify your cost-sharing model and your decisions on the dossier content, or to adapt the model if you cannot justify it based on the requirements of fairness, transparency and non-discrimination.

To anticipate the questions you may need to answer, you can have a look at the web page Practical advice for sharing data and submitting jointly.

The individual proportion of the costs depends on how many co-registrants share the data. It makes a significant difference if the costs are shared between 2 or 200 registrants.

The number of co-registrants who share the costs may not be clear when you are preparing your registration. This means that the calculation of the price is based on the current number of co-registrants.

A reimbursement scheme will make sure that the costs are equally shared. Each time a new potential registrant buys access to the data, the overall costs for each co-registrant will reduce. When and how frequently the price is re-calculated needs to be agreed.

Having a reimbursement scheme is mandatory, unless you unanimously agree not to have one. In some cases, running a reimbursement scheme may be more costly than the potential reimbursement. If there is no reimbursement scheme, you need to be able to clearly justify it to your future co-registrants and show the mutual benefits of such a choice.

Note that future registrants will have the right to ask for a reimbursement scheme even if all earlier registrants agreed not to have one.

You must have a formal data-sharing agreement. You should include at least information about the substance sameness criteria you apply, scientific dossier content (intrinsic properties of the substance), the method of calculating the cost sharing and information on the reimbursement scheme and future costs.