As a firefighter with a rural mid-west fire district, I see more fiberglass handles in the fire service. My best guess is that it is a maintenance issue. Fire axes get a lot of abuse. They get used to chop things that would normaly make people cringe, like door hinges to name one. The handles get hit a lot, because when you're tired your aim gets off. Yes it is dangerous to work tired, but you have to accomplish the mission. They are laid in who knows what in fire debris. Fiberglass does not absorb the water and other junk like wood. They are exposed to all types of weather on the outside of apparatus. Wood used in fire axes doesn't seem to stand up to exposure as well. I have seen dry rotted handles on fire apparatus. Not a good thing I know, but it is reality. Maintenance is not always the priority it should be. They get used to pry things a lot of times because you don't have a prying tool, wood breakes easier when prying from the side. I'm not sure what the large career departments use but small rural seems to head towards fiberglass from my observations. All this is very different from the use I was taught in Scouting. Hope this helps. I will defer to others with more knowledge as far as ax use for its intended purpose.