Directive 94/9/EC, commonly called the ATEX ("Atomsphères Explosibles") Directive is one of a number of new approach directives developed by the European Union and covers all equipment and protective systems intended for use in potentially explosive atmospheres. The Directive is now in effect and will become mandatory on July 1, 2003, superseding all previous legislation related to products used in explosive atmospheres. The ATEX Directive covers the following major elements:

With the exception of some components, products entering the European common market are required to bear mandatory CE (Conformité Européenne) marking. Application of the CE marking is a declaration by the manufacturer that the equipment:
The CE Marking is supported by a manufacturer's Declaration of Conformity, a Technical Construction File and when applicable an EC Type Examination Certificate.
In addition to the ATEX Directive, equipment must meet all applicable European directives, such as the Electromagnetic Compatibility (EMC) and Machinery Directive. Although products for use in potentially explosive atomspheres are explicitly excluded from the scope of the Low Voltage Directive, all "low voltage essential objective" have to be addressed by the ATEX Directive per Annex II clause 1.2.7.
To validate CE marking of their equipment, manufacturers must draw up a written EC Declaration of Conformity. This declaration is the document in which the manufacturer officially declares that the product complies with all the essential requirements of the directive currently mandatory.
The main elements of the declaration are as follows:
The fundamental safety requirements for all equipment are contained in Annex II, Essential Health and Safety Requirements, of the ATEX Directive. These essential requirements establish principles of integrated explosion safety from all electrical and non-electrical (i.e. mechanical friction and overheating, impact of metal parts, static electricity etc.) ignition sources. Conformity to harmonized European standards, such as the EN 50000 series, is used to demonstrate compliance to the Essential Health and Safety Requirements.