To join a union or not join a union?

I work in a state hospital that is in real trouble. This facility might be in jeopardy of closing. The job is potentially dangerous and the state is making it more dangerous by changing the rules. I feel (and most of my coworkers) that we have been treated unfairly at one point or another in the past year alone. I've often wished that I had some contact that would actually do something when I complained. Suddenly, a state union has showed up. Should I join?