It makes me giggle to think how many people think that they would be terminated if not for the union. I have never held a union job and my job comes with some serious responsiblity and accountability....and guess what...I've made some pretty stupid mistakes that cost the company a fair amount of money, but I've never feared for my job and I've never been afraid of being fired for making a mistake.
You're very fortunate. I've seen incidents where someone was terminated who followed all policies and procedures and, because something went wrong, got fired because the client demanded someone's head.