REGULATION & COMPLIANCE contentious from the start, with other countries, including the UK, favouring the original Not Classified status. It was based on animal studies showing lung tumours in rats at high exposure levels, although the data demonstrating any correlation in humans has not proved conclusive. As TiO 2 is used widely in industry, from paints to plastics, cosmetics and more, the classification caused significant concern. Industry decided to challenge it in the European General Court.
In 2022, the General Court annulled the classification on the basis of‘ manifest errors’. ECHA and the French authorities appealed, but the decision was ultimately upheld in the European Court of Justice. Therefore, as of 1 August 2025, the carcinogen classification has been removed from TiO 2
. In its wake, it has left a precedent that industry may choose to use again when challenging classifications it believes are not scientifically sound.
Brexit causes divergence
During the tribulations related to TiO 2 in Europe, a fundamental political change occurred as the UK left the EU. As of 1 January 2021, the UK has implemented its own versions of chemical legislation, including REACH and CLP. In general, industry has pushed to maintain alignment with the EU, as it remains the UK’ s closest trading partner and alignment reduces the costs of placing products on both markets.
However, since Brexit, divergence between the two sets of legislation has gradually increased. Whilst some of this is due to necessary regulatory differences, or the reduced capabilities of UK authorities compared to ECHA, changes are also emerging where the UK has purposefully decided to disagree with EU implementation. Taking the TiO 2 classification as an example, it was realised that, although the 14th and 15th ATPs were meant to have been copied into UK law, this had not been done via the initial legal mechanisms, as their date of compliance in the EU was after the date of Brexit. Therefore, in January 2024, the UK had to legally readopt these classifications.
However, during this process, both the classifications for TiO 2 and granulated copper were removed, creating a deliberate divergence. This was done because the UK authorities did not agree with the scientific evidence provided by the EU.
Other substance classifications have also begun to diverge. Whilst the UK authorities are required to evaluate the information provided by the EU, they are free to make their own decisions based on other available data. So far, the number of substances with differing classifications is small and mostly associated with biocidal substances registered as part of the GB Biocidal Programme.
This list does include some notable examples, such as the fragrance D-limonene, which has an Aquatic Chronic Category 1 classification in the UK and a Category 4 classification in the EU. This is significant, as it can cause confusion about how products containing substantial quantities of the substance should be labelled for transport.
Further divergence likely
The regulatory divergence between the UK and EU is unlikely to move back towards convergence anytime soon. The EU continues to move forward at pace, while UK authorities are introducing additional provisions that reduce their requirements to assess EU data when evaluating substances for their own regime. However, this direction runs counter to the general wishes of industry, which still strongly favours alignment wherever possible.
In March 2023, the EU introduced a series of new hazard classes for persistent, bioaccumulative and toxic( PBT) substances; persistent, mobile and toxic( PMT) substances; and endocrine disruptors( EDs) via Regulation 2023 / 707. This was an unusual move, as the typical pathway for introducing new hazard classes is through the Globally Harmonised System( GHS) before regional adoption, allowing countries to decide if and when to implement them.
It is believed that the EU authorities have taken this approach to push the new classifications through the GHS process more quickly. However, it has mostly caused backlash within GHS countries, with some, like the
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