In February 2020, the European Commission incorrectly classified certain powder forms of titanium dioxide (TiO2) as a category 2 suspected carcinogen by inhalation, which applied from 1 October 2021. This classification has since been reviewed and annulled in a judgement delivered by the General Court of the European Union on 22 November 2022.
The principal reasons for the annulment were that an error had been made in the assessment of the reliability and acceptability of the study on which the classification was based, and that a classification can only apply to a substance that has the intrinsic property to cause cancer. The classification still applies as it is currently being appealed to the European Court of Justice (ECJ).
Interpretation of the classification
The entry for TiO2 in Annex VI of the classification, labelling and packaging of substances and mixtures Regulation (CLP Regulation) is much more complex than typical entries in the CLP as the classification is limited to inhalation, accompanied by several specific notes intended to limit its scope, and has terminology which is new under the CLP. For example, the EU attempted to limit the classification to powders and the entry for TiO2 includes the following text ‘in a powder form containing 1% or more of particles with aerodynamic diameter ≤ 10 μm’.
This means that if TiO2 or mixtures containing TiO2 are not in this specific form, the classification does not apply. It is also ambiguous and can be subject to multiple interpretations. For example, liquid and some solid mixtures are not classified, but, as a result of the classification, specific warning statements and labels need to be applied to those that contain more than 1% of TiO2.
To address these issues, the TDMA have developed a comprehensive interpretation of the scope and application to help manufacturers, importers and downstream users in applying this classification. The European Chemicals Agency (ECHA) also prepared specific guidance of the TiO2, classification though it does not cover a number of aspects included in the TDMA interpretation.
The vast majority of TiO2 grades are not classified
TDMA carried out a testing programme to measure the content of particles with aerodynamic diameter ≤ 10 μm, one of the two criteria for classification under the CLP Regulation. In the absence of officially designated method, several grades of TiO2 were tested according to internationally recognised test methods for dustiness. The results indicate that these methods have minimal variability and are suitable for this application.
The data consistently shows that the vast majority of grades of TiO2 do not meet the criteria for classification. This means that most bags of TiO2 will not have warning labels that are noted in Annex VI of CLP.
Science of the classification
Background on the EU CLP Regulations
The CLP regulation use standardised labelling of substances and mixtures to provide information about the intrinsic potential hazards of different chemicals. The classification of substances under the CLP regulation is purely hazard based and does not reflect the actual risks related to the use of a substance and therefore it does not consider whether there is an actual or potential exposure to the substance.