Introduction
The European Commission often relies on scientific evidence for its regulatory decisions. But when challenged, how much deference is owed to the regulator's interpretation of the underlying science? This question came up in Joined Cases C‑71/23 P and C‑82/23 P concerning the classification of titanium dioxide – a chemical used in products like cosmetics and medicinal products – as a suspected human carcinogen. The Commission's decision was based on technical input from the European Chemicals Agency (ECHA). After the General Court (GC) struck down the classification, criticizing the technical input, the Commission and France appealed. They argued that the General Court had overstepped its judicial role. The Court of Justice (ECJ) upheld the annulment, confirming the Court's power to review the technical reasoning behind a regulatory decision.
Classification under the CLP Regulation
The CLP Regulation 1272/2008 requires that certain hazards, such as carcinogens, are classified and labelled uniformly in the EU. To that end, it lays down a specific procedure. A classification proposal can be submitted by a national authority, or by a manufacturer, importer, or downstream user. ECHA's Committee for Risk Assessment (RAC) then reviews the proposal and issues an opinion. That opinion, along with any comments received, is sent to the Commission, which takes the final classification decision.
The ECHA RAC applies the classification criteria in the CLP Regulation. For carcinogenicity, the relevant criteria are set out in Section 3.6 of Annex I. Depending on the strength of the evidence, a substance may be classified into:
- Category 1: known (category 1A) or presumed (category 1B) human carcinogen; or
- Category 2: suspected human carcinogen.
Titanium dioxide's classification and its annulment by the GC
Titanium dioxide is used for its colorant and covering properties in various products, such as paints, coating materials, cosmetics, medicinal products, and toys. The saga of its classification under the CLP Regulation goes back many years.
- In 2016, the French health & safety authority submitted a dossier to ECHA, proposing classification of titanium dioxide as a category 1B carcinogen.
- In 2017, the ECHA RAC adopted an opinion in favor of classification as a category 2 carcinogen, so one hazard level down from France's proposal.
- On the basis of the ECHA RAC's opinion, the European Commission then adopted Delegated Regulation 2020/217, formally classifying titanium dioxide as a category 2 carcinogen.
A category 2 classification brings with it important restrictions. In 2020, several suppliers and downstream users of titanium dioxide therefore brought annulment actions against the classification. They prevailed. In 2022, the GC struck down the Commission's Delegated Regulation (Joined Cases T-279/20, T-283/20, T-288/20).
The case turned on the so-called 'Heinrich study', which was a decisive element of the ECHA RAC Opinion, and therefore also for the Commission's contested classification and labelling.The GC found that the RAC had failed to properly consider the particle density in its interpretation of the study. This flaw amounted to a manifest error, making the study insufficiently reliable, relevant and adequate for the assessment of the carcinogenic potential of titanium dioxide. As the Commission had relied on the ECHA RAC Opinion, it too had committed the same error.
In 2023, the French Government and the Commission appealed the GC's judgment. The Advocate General concurred, but the ECJ stood by its GC.
The GC correctly assessed the technical ECHA RAC Opinion
The appeal was based on two related complaints.
Firstly, the appellants alleged that the GC distorted the evidence and erred in law by considering the Heinrich study to be "decisive" for the ECHA RAC opinion. They maintained that the RAC had relied on multiple studies and conducted a 'weight of evidence' assessment rather than giving determinative weight to a single study.
The ECJ upheld the GC's assessment. The ECJ remarked that to say that the study was decisive is not to say that the RAC's opinion was based on that study alone. The GC did not deny that the ECHA RAC had also taken other studies and factors into account, but correctly noted that those played a supporting role.
Finally, the 'weight of evidence' approach applied by the ECHA RAC does not contradict the finding that one study was decisive. While that approach implies that information has been considered holistically, it did not preclude the RAC from attributing more weight to some evidence (here: the Heinrich study) over other evidence.
Secondly, the appellants argued that the GC overstepped its judicial role by criticizing the determination of the particle density – a technical matter within the ECHA RAC's discretion.
The ECJ recalled the basic principle that the EU authorities indeed enjoy broad discretion when it comes to assessing complex scientific and technical facts. EU judicial review is limited to checking for a manifest error of assessment or misuse of powers. The question, therefore, is whether, in criticizing something as technical as particle density, the GC unlawfully encroached upon the EHCA RAC's discretion or lawfully identified a manifest error?
The ECJ approved of the GC's review. Despite the EU authorities' broad discretion, the EU courts may verify that the authorities have not ignored relevant elements that could have altered the overall assessment of the evidence and made the contested decision implausible. Consequently, the GC was right to reproach the RAC for failing to properly assess the particle density for titanium dioxide.
The ECJ did temper the GC's approach somewhat, though this nuance left the case's outcome unchanged. While the GC was entitled to scrutinize the authority's reasoning, the ECJ held that the GC had 'crossed the line' when it specified the particle density that ought to have been applied. In doing so, the GC had replaced the competent authority's technical judgment with its own and so had overstepped its role. In essence, the GC's role is limited to a negative review: it may identify manifest errors in a technical assessment. It is not tasked with a positive review – that is determining the correct technical outcome. This distinction is subtle, because identifying an error will often require engaging with the very considerations that shape the correct result. In any case, this legal fine-tuning did not affect the outcome of the case as the ECJ upheld the GC's conclusion to strike titanium dioxide's classification.
The importance of this ECJ judgment
By fully dismissing the appeals, the GC's judgment stands, which has prevented France's attempt to classify titanium dioxide powder as a suspected carcinogen under the CLP Regulation.
More broadly, the case is important because it confirms that although EU regulators have broad discretion in assessing complex scientific evidence – and the EU courts are generally deferential in that regard – that discretion is far from absolute. The Commission and ECHA tried to convince the ECJ that the science underpinning the Commission's decision lay beyond judicial scrutiny. The ECJ disagreed. Regulatory decisions must be based on a well-reasoned analysis that addresses all relevant factors, something the EU courts are willing to review, including by scrutinizing the underlying technical details.
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