The gas mask point is a valid one.
My Ex works for a water treatment plant. They are not allowed beards because, in an emergency, it is next to impossible to get an air tight seal with a respirator.
I also knew a trucker who was not allowed inside an oil refinery without shaving his beard, for the same reason.
That’s right, not even to deliver. All the local companies knew about the rules and they only sent clean-shaved guys on that run. (They didn’t have any women) I was told that everyone working in the plant was facial hair free.
Have you ever seen a victim of a Blister agent? There is no way I would want ANY exposed skin.
As far as beards go, a good majority of the Chemical caused casualties in the Iran-Iraq war were bearded men with improperly sealed masks.
I have never personally met a victim of a blister agent, but anyone who was reading any of the news magazines from the late '80’s would have seen pictures of the Iraqi victims. I have been exposed to riot gas, and I do not desire to do it again (and the effects of riot gas are temporary and non-lethal). The mask itself only covers your face not the rest of your head, neck, hands… There are other pieces of clothing that must be donned to ensure that no skin is exposed. (Although the hood which covers the neck and head is connected to the mask, it does not “seal”.)
Beards were phased out in the early eighties first for officers, CPOs and junior inlested. For a while only first, second and third class petty officers could have them but that ended on new year’s day '85.
Beards do intefere with a mask seal but I know from firsthand experience that an OBA (oxygen breathing apparatus for firefighting) works fine even with a short beard.