Gimme a Break! (1981) : 2x13

The Chief finds a cigarrette in his sock and questions each of the girls about it. When he finds out that Samantha and Katie don't smoke, he tears through Julie's room and then appologizes when she tells him she would never smoke. However, she smokes when he leaves the room but he catches her. She then moves to Grandma and Grandpa's after he hits her and it's up to him to get her to come home. He tells her that years before he and Margaret were smokers and he quit and so did she, but went on and off until it was too late and she got lung canger and died. In the end, Julie realizes that is the reason why he slapped her and she agrees to come home and stop smoking.