Melaleuca alternifolia Leaf Oil under harmonized classification

annolim
Feb 19
3 min read

Reproductive Toxicity Category 1B and hazard statement May damage fertility. May damage the unborn child.

In November 2023, the Risk Assessment Committee (RAC) of the European Chemicals Agency (ECHA) adopted an opinion to classify Tea Tree Oil (Melaleuca alternifolia) as a Category 1B Reproductive Toxicant (Repr. 1B - H360) under the EU Classification, Labelling, and Packaging (CLP) regulation. This classification indicates a high, harmonized concern that the substance may damage fertility or the unborn child, with potential consequences for its use in EU consumer products.

Key Aspects of the RAC Assessment:

Classification: Repr. 1B (May damage fertility or the unborn child).
Basis: The classification is based on animal studies, with the RAC acknowledging that in vitro studies show differences in the metabolism of p-cymene (a component of the oil) between rats and humans.
Other Hazards: The RAC also classified the oil as a Flammable Liquid Category 3 (H226) and noted potential for skin/eye irritation and sensitisation.
Scope: The classification applies to Melaleuca alternifolia extract and essential oil (CAS no: 85085-48-9).

Impact on Cosmetics and Regulatory Status:

Potential Ban: Under EU Cosmetics Regulation (EC) No 1223/2009, substances classified as CMR (Carcinogenic, Mutagenic, or Toxic for Reproduction) Category 1A or 1B are generally prohibited, meaning this classification could lead to a ban on tea tree oil in EU cosmetics.
Safety Evaluation (SCCS): Following the RAC opinion, the Scientific Committee on Consumer Safety (SCCS) was tasked with reviewing the safety of tea tree oil in cosmetics. As of mid-2025, the SCCS considers tea tree oil safe only under specific, strict concentration limits and in specific product types (e.g., up to 2.0% in shampoo, 1.0% in shower gel/face wash, 0.1% in face cream), excluding spray products.
UK Position: As of August 2025, the UK Health and Safety Executive (HSE) issued a final opinion that disagreed with the RAC’s classification of tea tree oil as a CMR 1B (reprotox) and is re-assessing the mandate, creating a difference between EU and UK regulatory approaches.
Timeline and Future Actions:
The European Commission has recently evaluated the classification with a potential to update Annex VI of the CLP Regulation.

Based on the 24th Adaptation to Technical Progress (ATP) to the CLP Regulation (Regulation (EC) No 1272/2008) and the corresponding ECHA Risk Assessment Committee (RAC) opinion (adopted Nov 2023), Melaleuca Alternifolia (Tea Tree Oil) was classified as a Category 1B Reproductive Toxicant (Repr. 1B - H360).

This classification, often categorized under CMR (Carcinogenic, Mutagenic, or Reprotoxic) substances, means it is considered to have a significant potential to impair fertility or harm an unborn child.

Basis for the Classification

The classification was based on the following:

Animal Studies on Reproductive Toxicity: The RAC concluded that evidence from four animal studies indicated clear adverse effects on male fertility (decreased sperm count and mobility) and potential impacts on female fertility (changes in implantation affecting litter sizes).
Active Component (p-cymene): Evidence suggested that the reproductive toxicity is linked to the component p-cymene, which is present in Tea Tree Oil at approximately 5%.
Species-Specific Metabolism: While the RAC acknowledged studies showing that p-cymene metabolism differs between rats and humans, they found the animal evidence sufficient to warrant a strict Category 1B classification.
Rejection of Lower Classification: The RAC adopted the 1B classification (presumed human reproductive toxicant) rather than the less severe Category 2 classification originally proposed by Poland.

Context of the 24th ATP

The 24th ATP to the CLP Regulation introduces new harmonized classifications for CMR substances. Under EU Cosmetic Regulation (EC) No 1223/2009, this classification (Article 15) usually triggers a ban for use in cosmetics unless it is evaluated and found safe by the Scientific Committee on Consumer Safety (SCCS).

Let`s read our previous post -> Tea Tree Oil in EU Cosmetics

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