https://ohr.edu/this_week/insights_into_halacha/5717
The Gadol Hador, Rav Moshe Feinstein zt”l, in a brief, albeit pivotal teshuva dated several months after the Surgeon General’s initial report,[14] wrote that although it is certainly appropriate to abstain from smoking, nevertheless, one cannot say that smoking is outright assur, as there are many people that smoke. Therefore, smokers fit into the category of “Shomer Pesaim Hashem, Hashem watches over fools.”[15] Rav Moshe adds that especially since many Gedolim smoked, it is impossible to say that such an act is truly forbidden.[16] This responsum seems to be the primary justification for many a smoker.
In fact, even Rav Moshe himself, in subsequent teshuvos dated 1981,[24] took a much stronger stance against smoking due to the health risks involved. Although he still would not call smoking outright assur, he nonetheless rules that due to the dangers of second-hand smoke, it is forbidden to smoke where it will bother others (a psak later echoed by many other authorities)[25] including Batei Midrash and shuls, and concludes with an exhortation that everyone, especially Bnei Torah, should not begin to smoke due to the chashash sakana, adding that it is assur to ‘get addicted’.
Several years ago, his son, Rav Dovid Feinstein shlit”a, was quoted as saying that with the current knowledge of the harm smoking causes, it is pashut that had his father, Rav Moshe, still been alive today, he would have prohibited smoking outright, as his dispensation was only based on the ‘fact’ that smoking endangered only a small percentage of smokers.[26] Indeed, in a newly discovered and recently published teshuva of Rav Moshe’s, dated Elul 5732, he himself wrote that his famous lenient psak was based on the facts as they were known at the time.[27] He added that if the metzius would change and the percentages of those proven harmed by smoking would increase, then certainly it would be prohibited to smoke, at least the amount the doctors considered harmful to one’s health.
