Summary and conclusions

Survey and safety assessment of Chemical substances in artificial nails and nail hardeners

The objective of this survey was

To make a survey of allergy causing chemicals in nail hardeners and products for manufacture of artificial nails to be sold to private persons from the retail trade, the internet and beauty shops.
Analyse selected products for their content of e.g. acrylic compounds
To perform health risk assessment of selected chemicals found during the analyses
To suggest a safe concentration of formaldehyde in nail hardeners.

A wide selection of products was purchased. Nail hardeners were purchased from the retail trade, while products for artificial nails could only be purchased from the internet. Except from this was nail tips that can be bought from the materialists etc. From a health perspective point of view, these products were assessed as not interesting and are therefore not included in this survey and instead acrylic nails (liquid and powder) and gel nails were focused on. The glues for fastening of these nail tips were however also included in the project.

The purchased products were examined and their labelling was assessed. Many of the checked products appeared not to be in accordance with the demanded labelling requirements. Most significant was the insufficient ingredient declaration and the lacking directions for use. As shown in this survey, directions for use are imperative especially for artificial nail products to secure a correct application of the products on the nails, which is extremely important to avoid allergy health risks.

Products for building up artificial nails can be divided into different systems. In this project products for building up acrylic nails (liquid and powder) - one of the most used systems - have been examined. Products for building up gel nails have also been analysed during the project. Only selected products of each system were included. They were product types considered to have the biggest content of acrylates, e.g. acrylic powders and belonging acrylic liquids.

Other product types (topcoat, primer, etc.) which are included in parts of the process were not included in the survey.

Product from the different purchased product groups were selected for analysis. Nail hardeners were analysed for free formaldehyde, whereas products for artificial nails were analysed for the acrylates:

- Triethyleneglycol diacrylate (CAS no. 1680-21-3)

- 2-Hydroxypropyl acrylate (CAS no. 999-61-1)

- 2-Hydroxyethyl acrylate (CAS no. 818-61-1)

- Ethyl acrylate (CAS no. 140-88-5)

- Ethylene dimethacrylate (CAS no. 97-90-5)

- 2-Hydroxypropyl methacrylate (CAS no. 27813-02-1)

Toxicological investigations of selected substances (formaldehyde, 2-hydroxyethyl acrylate 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate and ethylene dimathacrylate) were performed and the critical effects of the substances were found. Based on the toxicological investigations it is assessed that the critical effects of the main part of the examined substances is allergy. Besides, a review of the literature showed that allergy after use of artificial nails and nail hardeners is described.

A realistic worst-case scenario was set up for nail hardeners and the risk of systemic effects when using nail hardeners was calculated. The calculation showed that there is no risk of systemic effects when using nail hardeners containing the permitted amount of formaldehyde which is 5%. As formaldehyde can evaporate during the process, it is recommended to let in some air after application of nail hardeners to limit the exposure most possible by inhalation and deposition of vapour on the skin.

Formaldehyde may cause allergy and is classified as allergenic. Elicitation of allergy has been observed in formaldehyde sensitive persons in concentrations down to 0.05% formaldehyde, while induction of allergy in animal studies is seen at about 0.4 – 0.96% formaldehyde. The greatest risk of allergy is expected to develop if the nail hardener comes into contact with the skin. Exposure of the skin through application of nail hardener is expected to be limited, but application of nail hardener on the cuticle and the skin around the cuticle is hazardous and may cause allergic reactions. Irritation and allergy may also occur, if nail hardeners are applied on broken nails. In this case, formaldehyde may come into contact with the tissue under the nail and the risk of irritation and allergy will increase.

On the basis of the material generated in this project the permitted concentration of 5% formaldehyde in nail hardeners is assessed to constitute a risk of allergy induction in healthy persons and a high risk of elicitation of allergy in formaldehyde sensitive persons. Based on the literature presented in this report, a maximum concentration of 0.01% formaldehyde in nail hardeners is assessed to be a safe concentration in relation to the risk of allergy when applied both by healthy persons and persons already suffering from allergy. If the objective is to prevent healthy persons from developing formaldehyde allergy, a higher limit of concentration may be argued. However, this is difficult to set as there is no existing clear limit value for induction of formaldehyde allergy for this type of exposure. Formaldehyde is permitted as preservative in cosmetic products in a concentration of 0.2%. It can be argued that the concentration in nail hardeners as a minimum should not exceed this limit to diminish the risk of induction of allergy in healthy persons. A warning to already sensitive persons should appear on the product about the content of formaldehyde in a concentration above 0.05%. The Scientific Committee of Consumer Products (SCCP) in EU has been requested to assess a safe limit value for the content of formaldehyde in nail hardeners. This survey showed that several nail hardeners on the Danish market contains below 1% formaldehyde (4 out of 6 tested). Therefore, there are alternatives to the products containing larger amounts of formaldehyde. One product of the six tested only contains 0.01% formaldehyde.

The health assessment of product for building up artificial nails showed that there is not health risks of systemic effects related to the use. On the other hand, the risk of contact allergy by applying these products is assessed to be significant. This assessment was due to the amount of acrylates found in the products compared with the allergenic potential. Skin contact will result in a risk of contact allergy, as the products contain allergenic acrylate monomers in concentration of up to 15%. This applies specifically for the gel nails that contain high concentrations (up to 8%) of particularly 2-hydroxyethyl acrylate, which is considered to be the ingredient with the highest allergenic potential of the tested ingredients. In patch tests with acrylate sensitized persons elicitation of allergy at concentrations of 0.1% 2-hydroxyethyl acrylate was observed. The acrylic nails (liquid and powder) appeared to constitute a lower risk of contact allergy, as these products contain lower concentrations of the most allergy potent acrylates. However using the products still constitutes a significant risk of allergy.

The conclusion of the survey is that the products contain chemical substances in concentrations that constitute a significant risk of contact allergy. It has also been clarified how important the application of this type of project is. It is suggested that professional and competent personnel build up artificial nails instead of the consumer. This survey project does not comprise the working environment for personnel in beauty clinique’s etc., but it is important to emphasize that these products contain substances that may give rise to concern within the working environment. Many of the purchased products are marketed for professional use, but it is assessed that the private consumer will not have difficulty in obtaining the products for private use. However, the risk of contact allergy by use increases considerably, if the products come into contact with the skin. It is also assessed that the risk of skin contact decreases with the increasing experience in building up artificial nails.

The conclusions of the project are the following recommendations to the consumer:

Recommendations to the consumers

To reduce the amount of formaldehyde that is inhaled and deposited on the skin, the room should be well aired when you use nail hardeners

Be careful when applying nail hardener so that it only covers the nail and not the skin. This decreases the risk of formaldehyde.

Do not use nail hardeners containing formaldehyde on damaged nails. If the nail is broken, the ingredients can come into contact with the tissue under the nail and increase the risk of formaldehyde allergy.

Use qualified nail technicians for building up ”powder + liquid nails”, ”gel nails”, ”wrapping nails” and ”dip on nails”. These products should not be applied by private consumers, because the exposure of allergenic substances increases considerably