The European Union’s Court of Justice recently upheld the General Court’s decision to cancel the classification of titanium dioxide (TiO₂) particles, including nanoparticles, as a suspected human carcinogen. The classification was cancelled following successful appeals from manufacturers, producers and importers. An appeal to the General Court’s ruling by the EC and France was unsuccessful, and as a result, TiO₂ is no longer classified as a carcinogen.

CJEU Rejects Appeal to Reinstate Classification of Titanium Dioxide as Carcinogenic

On August 1st 2025, the Court of Justice of the EU European Union (European Union ) (CJEU) dismissed an appeal made by France and the European Commission (EC) to reinstate the classification of titanium dioxide (TiO₂) as a suspected human carcinogenic substance. In November 2022, the General Court had cancelled the classification, stating that the original assessment had not considered all relevant factors. In the appeal filed in February 2023, France and the EC argued that the General Court "exceeded the limits of its judicial review by carrying out its own evaluation and interpretation of the scientific data". With the dismissal of this appeal by the CJEU, TiO₂ is no longer classified as a suspected human carcinogen.

Classification of TiO₂ powders as carcinogenic

The TiO₂ classification debate began in 2016, when France proposed to classify TiO₂ particles as carcinogenic if inhaled. In 2017, the European Chemicals Agency (ECHA) Committee for Risk Assessment (RAC) agreed with the classification as a suspected human carcinogen, which was adopted by the EC in 2019. The classification would apply only if a mixture of powders contained 1% or more of TiO₂ and if the particle size was 10 micrometres or smaller. As a result, TiO₂ was included in the Classification, Labelling and Packaging (CLP) regulation. This regulation contains rules on the classification, labelling and packaging of chemical substances and mixtures placed on the EU market. Rules include that any hazards of an ingredient or product should be clearly indicated on the label.

Legal Challenges to TiO₂ classification

Several stakeholders, including manufacturers, importers, and suppliers of TiO₂, opposed this classification and took legal action. In November 2022, the General Court cancelled the classification, citing two main reasons. First, they judged that the RAC had made an error in assessing a toxicity study by not considering that TiO₂ particles can agglomerate. Second, the court ruled that the way TiO₂ induces cancer does not fit the classical understanding of “intrinsic toxicity”. Although the RAC argued that the CLP regulation allows for health hazard classifications triggered by physicochemical characteristics, the General Court did not agree. The General Court judged that the mode of action for carcinogenicity of titanium dioxide particles did not point to an intrinsic property to cause cancer. In its latest ruling, the CJEU did not address this dispute on the term ‘intrinsic properties’ in relation to the classification, because the appeal had already been dismissed in response to the first plea.

Reflection by RIVM

TiO₂ particles can cause tumours in rats when they are inhaled. However, scientists are still debating whether this effect might also happen in humans. In rats, the tumours appear to be caused by an ‘overload’ of particles in the lungs, which can eventually lead to tumours. RAC believes that this can also occur in humans, while others argue that rat lungs respond differently, and humans are unlikely to inhale enough particles to reach an overload condition.

RIVM believes that, based on current knowledge, we cannot completely rule out the possibility of lung tumours in humans due to high exposure to TiO₂. RIVM supports classifying TiO₂ as a suspected human carcinogen after inhalation, as it would be a precautionary measure to protect human health.

The CJEU did not clarify what is meant by the term ‘intrinsic properties’. The CLP regulation states that a substance can be classified as a carcinogen if it has an intrinsic property to cause cancer, but the term “intrinsic property” is not defined. RIVM supports RAC's opinion that the CLP regulation allows for a health hazard classification that is triggered by physicochemical characteristics, but also thinks that an examination by the court of the term “intrinsic property” would have been helpful.

As a result of the recent ruling, there is no longer a legal requirement to classify and label certain powder forms of TiO₂ as a suspected human carcinogen . This decision not only affects TiO₂ but also sets an important precedent for how other comparable substances may be evaluated in the future. It also highlights the need for more precise language in scientific opinions that influence regulatory decisions.