But the waitresses choose to work there. Yes, I know they have rent to pay, but so do the guys building skyscrapers. They assess the risk, and they choose to do the work. If second hand smoke was really a big problem for employees, then bars would have a tough time finding waitresses and the average salary for working in a smoke environment would go up.

Should we exterminate bears because they put park rangers at risk who have "no choice" but to work there?

I believe a bar owner has every right to not allow smoking in his bar, but the government has no right to tell him he can't smoke in his own building. Nobody is forced to endure a smoky environment (unless they are a child). Whether they're an employee or a customer, they choose to go in and take the risk. However, I would support a law that would require employers to inform their employees of the risks they are taking and things they are breathing, but you would have to be retarded not to realize that you are breathing smoke in a bar.