These are the warriors of the project world, the crisis management specialists; the people who enjoy eighteen hour days and working all night to meet a deadline. There are times when you need these folk. However you don’t need them all the time.
One of the problems with firefighters is that they see all situations as fires. When your only tool is a fire hose then all events are a conflagration. In some cases they are so addicted, yes, addicted, to living in crisis mode that they deliberately go there. They let the project slip so that extreme measures are needed.
They are like, fortunately rare, actual firefighters who resort to arson in order to get the adrenaline buzz. In addition they glory in working extreme hours and look down on those who plan their work more prudently. There gung ho attitude can lead to project team burn out well before you’ve reached any critical stage on the project. They can also burn through your project's budget if overtime is charged or uses consultants. This attitude is especially prevalent in software project teams.
Handing this behavior is the project manager’s responsibility. It’s your budget and you have to manage it. So restrict over working from the start of the project. Limit their hours and if need be send them home at a reasonable hour.
I was working on a major project with a large insurance company when I noticed that one of my staff was signing on at midnight on a Saturday night! So on Monday morning I asked her what was going on. I got her answer, which was actually reasonable, and then gently informed her that she should curtail it. I was going to need her when the new system came on line and an exhausted programmer was no good to me, she’d create more bugs than she was fixing.
Fire fighters are also judgmental. They judge everyone by the hours they work rather than the value they provide. If you let their opinions color the perception of team members you run the risk of alienating and losing good people. On a project I had a couple of fire-fighters who viewed another programmer as a slacker. Well I had him transferred to work for me at another location and I found out he did great work without the need to be one short step for hysterics every time we had a small hitch. Worked wonders for my budget and stress levels.