Let me tell you about what my union did for me. I am a federal employee in a large building for a large agency. I get paid well and have many fine benefits. One day some years ago a rat died in the subfloor under my desk. I called in a work order for the dead rat and not much happened. A week went by and the rat smell intensified. I asked for an update on the rat issue and was told it was in the system and awaiting a tech. Another week and it was unbearable. I spoke to my union rep, he made a few phone calls, and the next day they took apart my floor and removed the dead animal from under my cube.
This is one reason you need the union guy. All of my managers agreed that there was a problem, but they all were powerless to fix it. The union guy put on his hat with the extra bit of legal force and the problem is solved.