To speed up the identification of chemicals that need regulatory action, authorities may decide to address groups of structurally related substances rather than single substances. This grouping approach:

• Brings consistency and coherence for regulatory actions on similar substances.
• Makes it faster to identify substances that need regulatory action as well as those for which no further action is needed at this stage. This also supports informed substitution by industry. 
• Helps avoid unnecessary animal testing and enables to use all data available.

Grouping structurally related substances

The groups of substances are primarily formed based on:

• structural similarity, using the substance identity information in registration dossiers and C&L notifications; and
• associations made between substances by the REACH registrants (through read-across and categories) and by other parties (e.g. OECD categories).

The starting point for the group is structural similarity, however, in some cases additional considerations (in parallel with the structural similarity) may be needed such as grouping around a similar technical function or use (e.g. flame retardants) or around a specific constituent of concern. Structurally similar substances are identified from all the registered substances (the chemical universe). Certain substances are pre-selected to act as ‘seeds’. ECHA’s IT tools are then used to identify other substances that are structurally similar to the seeds.

This provides a starting point for grouping substances that may eventually require regulatory action.

Note that this work is different from grouping as defined in Section 1.5 of Annex XI to REACH because the scope and intended use of ECHA grouping are different and therefore the methods used do not constitute validated read-across and category information. This work provides a starting point for grouping substances for which eventually regulatory action may be needed.

Grouping and the chemical universe

Grouping aims to speed up the work authorities do to address all registered substances in the chemical universe.

ECHA, the Member States and the European Commission have developed an approach to assess the groups. The approach can also be used to cover a specific function or use such as different flame retardant chemistries or plasticisers.  For some groups of substances, cooperation with industry sectors has also been done or is ongoing. Examples are the Petroleum and Coal stream substances working group (PetCo), the Metals and Inorganics Sectoral Approach (MISA) and the collaboration with CEFIC on dossier compliance.

Once the grouping is done, substances belonging to the groups can be assessed. As a result, substances are allocated to appropriate pools within the chemical universe and later to different REACH and CLP processes.

Assessing the groups and identifying further regulatory actions

The screening of registered substances started after the first registration deadline in 2010. It focused on substances that had enough hazard information to conclude on the need for, and to initiate, the required regulatory risk management. This systematic screening work has over time enabled the identification of the vast majority of such substances that could go directly to regulatory risk management. As a result, most of the remaining substances are those requiring generation of further hazard information. Assessing substances in groups rather than individually, speeds up the identification of such cases, in particular, compliance checks.

For each group of substances, authorities consider whether there is a need to initiate further regulatory risk management activities for the whole group, for a subgroup or for individual substances within the group. 

The early assessment and identification of potential further regulatory risk management needs, including where further hazard information needs to be generated before the hazard can be sufficiently clarified, aims to speed up the work by supporting authorities to promptly proceed with processes such as harmonised classification and labelling or identification as a substance of very high concern (SVHCs) and restrictions.