Who decides what words are acceptable and which ones are not in our public schools?

I have to say that I got a little mad when my 5th grade son came home from school a couple days ago and told me that "Hell" was a bad word! I personally do not feel the word should be catagorized as profanity and it has so far been very difficult to find the person or committee it is that decides such a thing without asking MY opinion! I would really like to hear anyone elses opinion on this matter but I am especially interested in a factual answer as well.....Thanks