It is not clear to me to what extent we can be guided by ethical principles formed in a very different culture and 250 centuries ago...the Buddha did not know about tobacco. Neither apparently was it one of things he forsaw as posing a danger to his spiritual descendants. This is not surprising.
However WE know that smoking is linked to a range of cancers, not just lung, but eye, mouth, sinus, oesophagus ,larynx, stomach, kidney and bladder.
It is also strongly implicated in a range of heart diseases, emphysema, chronic bronchitis, infertility, babies who are small for dates, glaucoma and is a contributory factor in a whole host of other conditions including tooth decay, gastric ulcers and asthma.
We do not need to refer to culturally determined ideas of right livelihood.
Our own sense of what constitutes ethical behaviour should be sufficient.