[Lou L]

When is the last time a US soldier had to actually use a gas mask for anything but training?

In the US Navy, where firefighting is needed within enclosed spaces, special firefighting equipment is needed--equipment that fits over the face, and supplies oxygen to the firefighter. I think a thick, heavy beard would not be well-suited for such PPE.

[jospehm20]

And yet Navy allowed guys to grow beards back in the 70s and 80s.