Generally requirements for devices are put into place to minimize risk to people and to prevent unnecessary equipment from being brought into the area. I’ve always been able to carry my medical equipment into these areas, including those with Arc Flash hazards. Speak with your employer and the HSE team about it and there is likely a process already in place.
I travel a lot for work all over the world, including to many areas of high risk where full PPE is required, including FRC. I’ve been in surface and underground mines, offshore on vessels and oil platforms/rigs. Some of the most hazardous locations you can imagine, some I’m not even allowed to mention here.
Is the area you’re going to be working in specifically a Class 1/Div 1 (ATEX Zone 1) or a Class 1/Div 2 (ATEX Zone 2) area? Those are the toughest areas to get approvals for, but still possible - usually it’s the charging circuits that are hazardous, so you just don’t plug anything in while you’re within the hazard area. Sometimes it’s just a matter of just a few “high risk” areas that you’re not allowed in, but the general space is fine.
I wanted to add, remember that your medical equipment is a necessity, not an option! Whether it’s an insulin pump and CGM, or your glucose meter and insulin pen, its all the same. It’s hazardous for you, and potentially others, for you not to have it with you when you need it.
As a side note, I’m always allowed to carry snacks with me too - no matter where. Something else to keep in mind if you discuss it with your employer/HSE Team.