Registration is based on the ‘one substance, one registration’ principle. This means that manufacturers and importers of the same substance have to submit their registration jointly.

However, as a registrant, you can opt-out from jointly submitting information and submit some data separately, if: 

• it would be disproportionately costly for you to submit some information jointly; or
• submitting the information jointly would lead to the disclosure of commercially sensitive information that would likely cause substantial commercial detriment; or
• you disagree with the lead registrant on the selection of information.

ECHA verifies the following information during the completeness check if a registration dossier contains information marked as opted-out:

• There is a justification in line with Articles 11(3) or 19(2) of the REACH Regulation.
• All the information submitted as opted-out is complete.
• When the opted-out information is submitted to fulfil information requirements at a higher tonnage than those covered by the joint submission, all the relevant information requirements are addressed.
• When the opt-out is submitted using a token provided by ECHA, and you cannot rely on any of the information jointly submitted by the lead registrant, all the information required under REACH Articles 10 and 12 (or Articles 17 or 18) is included in the opt-out dossier and that information is complete.