I came in a bit late on this thread, but I'd like to throw my 2 cents in anyway. I came into this business back in 1975. My company was the only one in the region that required their people to be Nationally Registered EMT's with an ambulance rating (REMT-A). Ya I'm that old...
After some of the particularly bad calls, especially fatalities, the young EMT (me included) felt we'd screwed something up. It ain't supposed to go this way. Sure as hell didn't happen like that on "Emergency!"... The visual queues were there for others to see, and the older more experienced hands would take the younger one aside and have a chat. After the shift was over, the crews would assemble at the debriefing site (Ye Old Watering Hole & Beer Can Museum) and with the assistance of some adult libation, work their way through the situation. It had the advantage of solidifying unit integrity, passing on knowledge and just reinforcing trust between parners and coworkers. We truly were family. If one hurt, then we all felt it. And we worked thorough it together, as a unit and family.
I don't believe that having a Phd, licensed counselor, or church choir is needed to help in this situation. I have seen some supposed CISD "teams" that were nothing more than a recruiting team for a church under another name. These agencies do much more harm than good IMHO. But, one doesn't throw the baby out with the bath water.
A CI team need to be made up of experienced people from the immediate field of service. It does little good for a cop to work with a young firefighter that just hauled out his forst "roast", nor does it do much good for an EMT to work with a cop that just dropped the hammer on a suspect. While we are all emergency services, our job functions and experiences vary greatly. As should a crisis intervention team. I've seen things in my 35 years of service that no one should have to. I've been a victim and survivor, as well as initial responder to the largest natural disaster this nation has had. I've been shot at, stabbed, burned, brained and beaten. And what seems funny now, but sure as hell didn't at the time, came face to face (in the most literal sense) with a lizard that easily could have eaten my fat ass for lunch. You'll have to ask my laundry lady about my reaction to that one...
I still have nightmares about the things I've been through. But I've been able to make friends with many of the ghosts. In a strange way, I'm thankful I've had some of the reactions I've had because they still show that I'm a human being. The day I don't care anymore is the one I need to hang up my gear and get out of it, because that's when I've become a liability to my team.
Properly done, and not forced upon a person, CI can be a beneficial service. And it should be offered. But a blanket requirement to participate is not only wrong, but an insult to the worker. Many of my old partners are still in the business and feel the same way that I do. CI has it's place, but as far as I['m concerned, the best intervention we can have is our own people... There when you need them and with the same experiences. The family....
Just another point of view...