Equipment for potentially explosive atmospheres (ATEX) A potentially explosive atmosphere exists when a mixture of gases, vapours, mists or dusts combines in such a way that it can ignite under certain operating conditions. The ATEX Directive 2014/34/EU covers equipment and protective systems intended for use in potentially explosive atmospheres. The Directive defines essential health and safety requirements and conformity assessment procedures, to be applied before products are placed on the EU market, and is aligned with the new strategic regulatory framework, applicable from 20 April 2016, replacing the previous Directive 94/9/EC.