The rapidly developing regulatory framework surrounding the second wave of the COVID‑19 pandemic in both of CERN’s Host States, as well as the measures adopted within the Organization, can make it hard to keep track of and understand the applicable rules, in particular with respect to wearing masks. This article aims to clarify the current rules applicable at CERN for those of us working on site.

First and foremost, please note that it is now compulsory to wear a mask at all times in shared offices and meeting rooms, irrespective of compliance with other instructions, for example those related to proper ventilation and physical distance. This measure is mainly based on the 1 November decree by Geneva’s Conseil d'État, which stipulates the obligation for anyone meeting another person to wear a mask regardless of interpersonal distance and ventilation. A similar approach was adopted in France’s national protocol for workplaces, which made mask-wearing compulsory in all enclosed spaces.

The rules surrounding the types of mask allowed on site have not changed. We would like to remind you that the effectiveness of community masks (masques grand publics) cannot be guaranteed and that they are thus forbidden at CERN. Only Type I* surgical masks are allowed on site. They must be worn indoors at all times and handled as per the guidelines outlined on the HSE website, which follow recommendations by the Host States and the World Health Organization. One exception to this rule is FFP2/FFP3 masks (without exhalation valve**), which may be worn in specific situations, e.g. involving persons with vulnerabilities. As always, in order to effectively combat the spread of the virus, mask-wearing must be combined with the other protection measures outlined in the weekly COVID-19 information e-mail, such as observing an interpersonal distance of at least two metres as well as proper ventilation, frequent hand-washing with soap or – whenever this is not possible – sanitiser, and cleaning of surfaces.

If you have any questions on this subject, see the FAQ on the HSE website.

*Minimum acceptable performance class, in accordance with EN 14683.

**Except if the exhalation valve is covered with an EN 14683 certified material.