Article 5U.K.General obligations
To ensure the safety and health of workers, and in accordance with the basic principles of risk assessment and those laid down in Article 3, the employer shall take the necessary measures so that:
where explosive atmospheres may arise in such quantities as to endanger the health and safety of workers or others, the working environment is such that work can be performed safely,
in working environments where explosive atmospheres may arise in such quantities as to endanger the safety and health of workers, appropriate supervision during the presence of workers is ensured in accordance with the risk assessment by the use of appropriate technical means.