In New Jersey there wa a law protecting smokers, and perhaps other states that are big tobacco producers have something similar, like NC or KY. But in most states you are an employee at will and can be fired for any reason other than race, color, creed, sex, age, etc., and smoking status is not a protected class.
If it is an addiction perhaps there is some protection if your company is covered by the Americans With Disabilities Act or a similar state law, and smart employers pay for patches and classes.
But as an employer I could justify never hiring and always firing smokers. And an enviormental firm especially may conclude people who are self destructive and/or too stupid to realize the health risks to themselves or others and oblivious to the adverse impact on the enviornment and the possibility that clinging smoke (yes, it clings to you and your clothes and you smell of smoke) might mess up enviornmental testing just are not smart enough or have enough judgment to work here.
