ATEX is an abbreviation of a French term used to denote an explosive atmosphere.

ATEX is the name commonly given to the framework for controlling explosive atmospheres and the standards of equipment and protective systems used in them.

The framework is based on the requirements of two EU Directives:
1. Directive 99/92/EC (a.k.a. ATEX Workplace Directive) concerning minimum requirements for improving the safety and health protection of workers potentially at risk from explosive atmospheres;

2. Directive 94/9/EC (a.k.a. ATEX Equipment Directive) concerning equipment and protective systems intended for use in potentially explosive atmospheres. The aim of the latter directive is to facilitate trade of ATEX equipment within the EU by removing the need for separate testing and documentation in each member state.

New equipment or electrical installations in an ATEX zone must have an EX-marking in accordance with current legislation. This means that the equipment (e.g. light fittings, electric motors and pumps) must not be a source of ignition or emit substances that can lead to an explosion, for example by leaking, giving off sparks or becoming very hot.