Where I live, companies go so far as to FIRE existing employees who smoke...a friend of mine, she was good at her job, she brought in several accounts that made her company a profit, & they instituted a zero tolerance policy on smoking. They told her she could either quit (she was a 3 pack a day Menthol smoker) or be terminated.
She liked her job, and/or did not relish the idea of being a 39 year old woman competing for another job against 22 year old kids right out of college, so she tried to quit. She tried the patch, the gum, the chantix (by the way that doesn't work for everyone, just, FYI) and finally, when she was unable to quit, they terminated her. No severance package, no "we're sorry to see you go", no nothing. And they got away with it...she sued them for wrongful termination and she lost.