masques tissus
28/10/2020 3 min

Washable cloth masks sold by the brand DIM: assessment of the risks relating to fabric treatment using silver zeolite and silver-copper zeolite

ANSES recently received an urgent request to assess the potential risks relating to the wearing of washable cloth masks treated with two active substances, silver zeolite and silver-copper zeolite. These washable masks were brought to market by the company Hanes against the backdrop of the current COVID-19 pandemic.

An evaluation of silver zeolite and silver-copper zeolite is currently under way at European level, as part of the Biocides Regulation. ANSES has analysed the data provided by the mask manufacturer along with the findings of the evaluations carried out by the European authorities. The Agency found no evidence of a health risk providing that conditions of use are strictly observed. However, if the treated mask is worn without prior washing, or if is not changed when wet, ANSES cannot rule out a health risk.

A textile treatment that remains possible, pending the results of the European evaluation

Silver zeolite and silver-copper zeolite are active substances conferring antimicrobial properties. They are used in the manufacture of many everyday consumer articles and products, including paint, sealants, textiles, furnishings and hygiene and care products.

An evaluation of silver zeolite and silver-copper zeolite for certain categories of use is currently under way at European level, as part of the Biocides Regulation. Pending the results of this evaluation, these substances can be used to protect the fibres making up the fabric in order for it to last longer. This is the case of the washable cloth masks sold by the Hanes company, which ANSES was asked to investigate.

To carry out its expert appraisal, ANSES examined the scientific data taken into account as part of the European evaluation currently under way on the two active substances. It examined two scenarios for the use of masks: two new masks worn one after the other on the same day without prior washing, and a previously washed mask worn for eight hours a day. For each scenario, ANSES analysed the potential risks relating to dermal and inhalation exposure to the silver and copper ions released by the zeolites.

Based on the real conditions in which treated masks are worn, ANSES is unable to rule out a possible health risk

On completion of its expert appraisal, ANSES ruled out the potential for any immediate and serious effects on human health. This is confirmed by the absence of reports to poison control and toxicovigilance centres concerning any proven adverse effects relating to the wearing of these masks.

With regard to the medium-term risk, ANSES concluded that:

  • providing that precautions for use are scrupulously observed, wearing these masks has no harmful effect on human health, particularly in terms of reproductive toxicity. These precautions include washing the mask before wearing it for the first time and after each use, wearing it for no more than four hours and replacing it as soon as it becomes wet;
  • however, looking at situations of exposure that may arise in everyday life, such as wearing masks without washing them first or while they are wet, and “worst case” scenarios, ANSES considers that exposure may give rise to toxicological effects in the medium term, such as the accumulation of silver Ag+ ions in organs, and that health risks cannot therefore be entirely ruled out.

Products containing biocides: improving the regulation and evaluation of active substances at European level

Chemical treatment with biocidal substances is not part of the technical requirements applicable to protective cloth masks. Moreover, manufacturers are not required to mention treatment of this type on product labels. ANSES underlines the need for better regulation of the use of antimicrobial treatments in products, particularly everyday consumer goods. The implementation of the Biocides Regulation contributes to this regulation. 

Finally, ANSES recommends accelerating the evaluation of active substances at European level in order to ensure that treated items contain only active substances that have been approved as suitable for the product.

ANSES reiterates its recommendations, based on its expert appraisal of textile clothing, i.e. the importance of washing any clothing likely to come in contact with the skin before it is worn for the first time, following the washing recommendations issued by the manufacturer.