lilmod ulelamaid: “we only know what the Torah wants from us by listening to our Gedolim” The torah says you should not harm yourself. Smoking is harmful. What is there to ask?
But even if for some reason you thought that you should ask a rabbi, go ask them. But to say “because they don’t say anything they’re probably ok with it” is very very wrong. You should take responsibility for your actions. You don’t have to wait for anyone to tell you something is wrong when it’s clear it’s wrong.