RAC recommends first harmonised endocrine disruptor classification under CLP

The European Chemicals Agency’s Committee for Risk Assessment (RAC) has recommended, for the first time, that a substance is given a harmonised classification as an endocrine disruptor for human health under the EU’s new Classification, Labelling and Packaging (CLP) hazard classes.

RAC adopted its opinion on resorcinol (CAS 108-46-3) on 5 June 2026, recommending classification as Endocrine Disruptor for human health Category 1 (ED HH 1), EUH380: “May cause endocrine disruption in humans.” The opinion has now been published by ECHA and sent to the European Commission for decision-making.

Why is the opinion significant?

The new endocrine disruptor hazard classes were introduced into the CLP Regulation in 2023. ED HH Category 1 applies to substances considered known or presumed endocrine disruptors for human health, while Category 2 covers suspected endocrine disruptors.

The resorcinol opinion is the first RAC opinion applying the new human health endocrine disruptor criteria in a harmonised classification process.

RAC concluded that the available evidence was sufficiently convincing to support Category 1 rather than Category 2 classification.

The Committee identified evidence of endocrine activity, particularly effects on the thyroid hormone system, together with evidence of adverse effects and a biologically plausible link between the two.

RAC’s assessment describes a proposed mode of action involving inhibition of thyroid peroxidase (TPO), which can impair thyroid hormone synthesis. Reduced thyroid hormone levels can lead to increased thyroid stimulating hormone (TSH), with sustained stimulation of the thyroid associated with effects including thyroid enlargement, hyperplasia, goitre and hypothyroidism.

Importantly, RAC considered whether uncertainties in the evidence might support the lower Category 2 classification. It concluded that there was no serious doubt about the relevance of the observed effects to humans and that the evidence met the requirements for ED HH 1.

What happens next?

RAC’s opinion does not itself change the legal classification of resorcinol.

The opinion has been sent to the European Commission, which will consider whether the proposed classification should be incorporated into Annex VI of the CLP Regulation. The Commission, supported by the CARACAL expert group, prepares any subsequent delegated act. Once a harmonised classification is included in Annex VI, manufacturers, importers and downstream users must apply it.

If adopted, the new endocrine disruptor classification would sit alongside resorcinol’s existing harmonised hazard classifications.

The classification could also have consequences for mixtures containing resorcinol. Under the new CLP criteria, the generic concentration limit for an ED HH Category 1 substance to trigger classification of a mixture as ED HH Category 1 is 0.1%, unless a different specific concentration limit applies. For mixtures within the scope of CLP, this could affect classification, labelling, safety data sheets and supply-chain communication.

Resorcinol has a range of applications, including in cosmetics and hair dyes, rubber compounds, resins, wood adhesives and other industrial products. Businesses using resorcinol may therefore want to identify relevant uses and concentrations and consider the potential implications if the harmonised classification is adopted.

Finished cosmetic products intended for final users are not themselves subject to CLP classification and labelling requirements, so the practical regulatory consequences will depend on where resorcinol is used in the supply chain and which legislation applies.

Implications for other substances

The significance of the opinion extends beyond resorcinol.

As the first RAC recommendation for harmonised classification as an endocrine disruptor for human health, it provides an early indication of how the new CLP criteria may be interpreted and applied to other substances.

For businesses with substances that have potential endocrine activity, the opinion provides a useful case study of the evidence RAC considered when distinguishing between Category 1 and Category 2, including the weight given to mechanistic evidence, observed adverse effects, biological plausibility and relevance to humans.

The distinction is important. Category 1 requires sufficiently convincing evidence to support identification as a known or presumed endocrine disruptor, whereas Category 2 applies where the available evidence raises concern but is not sufficiently convincing for Category 1.

As further substances move through the harmonised classification process, a clearer picture should emerge of how RAC applies the new endocrine disruptor hazard classes across different modes of action and evidence bases.

RPA supports businesses and industry associations with CLP classification, endocrine disruptor assessment and the wider regulatory implications of substance hazard classifications. We can help organisations assess the evidence, understand potential downstream consequences and prepare for regulatory developments affecting substances and mixtures.