Discussion paper on the potential approaches to address unintentional mixture risks for future UK REACH assessments - update


Last updated: 29 April 2022

This is a paper for discussion.

This does not represent the views of the Committee and should not be cited.   

1. In September 2020 the UK Chemicals Delivery Board agreed that the Environment Agency should prepare a report on whether a mixture assessment factor (MAF) is a useful approach to address the potential risks arising from unintentional (coincidental) mixtures of chemicals under the UK REACH Regulation. Risks from intentional mixtures are already covered under the current regulatory system. This approach is also being considered by the European Union under EU REACH. Following that meeting, the UK Health Security Agency (UKHSA) agreed that they would work with the Environment Agency to prepare a joint report. Environmental aspects would be covered by the Environment Agency, and human health aspects by UKHSA.

2. The COT considered a former version of the draft report in March 2022. The report has now been updated and is attached at Annex A and has been provided to members of COT for their review and to comment on the human health aspects prior to finalisation of the report.

3. The report considers i) an overview of the current approach to the risk assessment of chemicals under UK REACH(Sections 1 and 2); ii) the methods available to consider mixture risk(Section 3); iii) a critical review of the evidence on the level of risk from unintentional mixtures(Section 4); iv) an exploration of the pros and cons of using a MAF, including implications for testing and practical and legal consequences(Section 5; v) critical evaluation of other possible approaches, based on existing EU guidance (e.g. from the European Food Safety Authority (EFSA)) or under development in other parts of the world; and makes (Section 5) vi) a scientific recommendation on the most appropriate way forward to address mixture risks under UK REACH(Section 6).

4. In light of COTs comments from the pervious meeting, changes have been made within Section 4 and to the conclusions in Section 6.

Questions on which the views of the Committee are sought

5. Members are invited to comment on the information provided in the report in Annex A and in particular:

     i. Consider the evidence base in the report (in particular in Section 4) and comment on whether the committee supports the conclusions on human health in Section 6.

     ii. Provide comment on the suggestions for further work in the report and whether there is any additional research that could be conducted to inform the UK view on addressing potential risks from mixtures.


May 2022