Obviously, it all comes down to balancing needs and risks. I just thought I'd point out how you can meet or exceed one requirement (flameproofing) but potentially create a new risk in the process.

It depends of what she/he consider protective gear. Kevlar is fine. Anything that is regulated, lawful, well tested, reliable and covered by the assurance is fine. Those new materials can't still be trusted at the same level and you don't want to be the first to discover in your company that they are acid permeable or burn like a torch when react with some chemical

To let some of your employees work with a lower protection against accidents than other employees, would be negligent and easily prosecutable in court. The non-vegane parents of a vegane killed in an accident would not doubt a second to sue you in this case.