Lead registrants in UK REACH

UK REACH retains the 'one substance, one registration' principle. If there is more than one registrant for a substance, co-registrants should agree between themselves who the 'lead registrant' will be.

Main responsibilities of lead registrants

The lead registrant is the lead contact for substance registration with HSE ('the Agency'). They will 'claim the lead' for the substance and are responsible for submitting a lead joint registration dossier containing the relevant Article 10 information, using the 'Comply with UK REACH' service. They should claim the lead within the service once the dossier is ready to be submitted.

This also applies where an on-site or transported isolated intermediate is manufactured or imported by more than one manufacturer or importer respectively.

The co-registrants should also submit their own company-specific information after the submission of the joint dossier.

The lead registrant is responsible for approving members into the joint registration group in 'Comply with UK REACH'. This links their company-specific dossier to the lead dossier.

Other responsibilities

On request, and where sharing of cost for data has been agreed in a fair, transparent and non-discriminatory way, the lead registrant should also share the data from the joint dossier with potential new registrants. Potential new registrants to the joint submission must make a request for data on animal testing.

Co-registrants may agree that the lead registrant should also submit:

  • guidance on safe use
  • the chemical safety report for substances manufactured/imported in quantities of 10 tonnes or more per year
  • an indication that the relevant information has been reviewed by an assessor chosen by the registrant and with relevant experience

If co-registrants ask for jointly submitted data to be treated as confidential, the lead registrant should request this.


If the lead registrant wants to withdraw, they should work with the co-registrants to agree a successor. The lead registrant status can be transferred to the successor by the existing lead registrant within the 'Comply with UK REACH' service.


There may be a dispute about who should be the lead registrant or co-registrants may feel the lead registrant is not fulfilling their responsibilities. The co-registrants should try to resolve any concerns within their group and with the lead registrant first. The lead registrant can only hold the position with the agreement of their co-registrants.

If the co-registrant(s) feel that the lead registrant should be removed, they should collect as much evidence as they can and email their complaint to [email protected] with the subject head 'LR Dispute'.

The Agency has the ability to remove someone's status as the lead registrant.

Further information

Article 10 information

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Updated 2022-03-30