Proposal to classify sodium fluoride as an endocrine disruptor and reproductive toxicant
As part of the Second National Endocrine Disruptor Strategy (SNPE2), sodium fluoride was identified as a substance to be assessed as a priority for its potential as an endocrine disruptor. ANSES therefore examined the available data to determine the type of hazard posed by the substance under the CLP Regulation. Since 2022, an "Endocrine Disruptor" hazard class has been included in this CLP Regulation, enabling this nature to be identified regardless of how chemicals are used.
Adverse effects on neurodevelopment and fertility
Sodium fluoride is already classified for the following hazards:
- acute toxicity (oral), Category 3 (H301, toxic if swallowed);
- skin irritation, Category 2 (H315, causes skin irritation);
- eye irritation, Category 2 (H319, causes serious eye irritation).
Experimental studies in rodents and epidemiological studies in human health have shown that sodium fluoride has effects on neurodevelopment following exposure during pregnancy, and that it alters thyroid function. These effects were observed following oral exposure. In addition, studies on animal models have shown impaired fertility.
In light of its assessment, the Agency therefore recommends extending the harmonised classification of sodium fluoride to the following hazard classes:
- endocrine disruptor for human health, Category 1 (EU H380, may cause endocrine disruption in humans);
- reproductive toxicity, Category 1B (EU H360F, may damage fertility).
If this classification is adopted by ECHA, and then by the European Commission, it will be necessary to label sodium fluoride with suitable warnings, hazard statements and precautionary statements, in accordance with the rules of the CLP Regulation, to ensure that workers and consumers benefit from clear identification and communication on the presence of these hazards.
Classification proposal submitted for public consultation
The harmonised classification proposal for sodium fluoride has been submitted for public consultation on ECHA's website until 16 January 2025. This consultation enables all stakeholders to submit comments or additional scientific data.
Following this consultation stage, ANSES will respond to the comments received. The initial proposal, comments and ANSES's responses to them will be analysed by ECHA’s Committee for Risk Assessment, which will then issue its opinion on updating the harmonised classification of sodium fluoride.
Based on this opinion, the European Commission may if appropriate draft regulatory texts allowing the chosen classification to be included in the CLP Regulation.
A substance mainly used to prevent cavities
Sodium fluoride is a chemical compound that dissociates into sodium and fluoride ions. The fluoride ion (or fluorine) is the main agent of toxicity. It occurs naturally in surface and groundwater; in certain parts of the world it may be found at high concentrations. The main contributors to fluoride intake are cereal-based foods, drinking water, tea leaves, milk and dairy products, as well as fluoridated table salt and toothpaste. Sodium fluoride is used in toothpaste to prevent tooth decay. In some countries, the substance is also added to drinking water. In 2013, EFSA assessed the benefits of fluoride and determined the adequate intake required to achieve a protective effect against tooth decay. In July 2025 it published a revised opinion on maximum intakes in drinking water, food and dental care products.
The Regulation on Classification, Labelling and Packaging (CLP)
Regulation (EC) No 1272/2008 on classification, labelling and packaging of substances and mixtures, known as the CLP Regulation, is the legislation in force in the European Union to ensure the protection of workers, consumers and the environment with regard to chemicals. In particular, it aims to identify any hazards posed by a substance or substance mixture due to its physico-chemical properties and its effects on health and the environment.
This Regulation defines how these substances and mixtures must be classified, labelled and packaged. It also has an impact on other European regulations able to translate hazard characteristics into stricter requirements, which may go as far as prohibition decisions or substitution obligations.
Once a substance or mixture has been classified with regard to the identified hazards, appropriate labelling informs the user about these hazards through pictograms and safety data sheets. ECHA is responsible for implementing the CLP Regulation.