We have an electric water kettle at work. It often develops a mineral coating on the inside on the bottom. Sometimes, the coating starts breaking up and little crusties float around in the water. Well, the department secretary told me to boil some vinegar in it to get rid of the mineral deposit. I've done this for quite some time. Today or yesterday one of the women in my office came in and said "hold your breath if you go into the copyroom (where the electric water kettle is), because SOMEONE is boiling vinegar!" I responded, "why yes, I am." She then said that I should boil the water first and then add vinegar afterwards. She said that the vinegar fumes are toxic. I decided to do some online investigation to see if the vinegar fumes really are toxic, and I came across this website. Basically, a science teacher got cited for having a sealed bottle of food-grade vinegar not in a special dangerous-acids cabinet. Go figure...your salad will kill you...or something.
I still don't know if vinegar fumes are toxic (annoying, but not toxic), but if you know better, let me know!