After some research, I found that ATEX can mean 2 European directives:
99/92/EC - risks from explosive atmospheres
"Objective: This Directive aims at establishing and harmonising minimum requirements for improving the safety and health of workers potentially at risk from explosive atmospheres."
2014/34/EU - equipment and protective systems intended for use in potentially explosive atmospheres
"Article 4 - Essential health and safety requirements
Products shall meet the essential health and safety requirements set out in Annex II which apply to them, account being taken of their intended use."
Since BMF055 is made for the consumer electronics market, I would request that you do not use this sensor for this application. Please contact your local sales office from Bosch Semiconductors to inquire if they have alternative parts that you can use in this application.