Can An Employer Discriminate Against Me Because I Smoke?

many cigarette butts for backgrounds

An AOL Jobs reader asks:

I am wondering what your opinion is on employers refusing to accept applications and/or offer of employment for a smoker. Smoking might be a health risk as is obesity or disability. I live in a state with many counties and one of them is going to start a "smoking ban" for new hires the previous county i lived in also did this all "fair"? Where are our rights going?

The employers claim it has to do with insurance issues but where I live now no employer gives employees insurance as most of the jobs are either part time or seasonal and not even part time when they give employees 10 hrs. per week. Where is the justification for this type of issue?