I agree with familytree.
I would also add experience, honesty, humor, sees safety as a moral virtue and not just a bumper sticker, doesn't believe they know it all but is confident in what they do know, a willingness to learn more themselves, a willingness to listen to their guys, will work with their guys to increase their knowledge, understanding, and safe work habits.
Also will encourage their guys to do what they are actually capable of, will not put them into situations they are not capable of doing safely or correctly, and will back their guys to the boss (or a jerk customer) when they know they're right.