Smoking tobacco vs. smoking pot – carcinogens
I cannot cite specific references, and I’m not in the research mood today. But I do recall hearing a lecture in college, provided with the actual scientific article that compared these two with specific regards to cancer risk. The carcinogen risk ration between cannabis:tobacco was approximately 400:1. I guess this suggests that a single joint was about 400 times the cancer risk of a single cigarette. If we are going to calculate that an average smoker is consuming a pack a day, which is 20 cigarettes, then the risk factor for weed is still 20:1. That is not small time danger. And with the halachos about the obligation to refrain from danger, this qualifies for an issur. And furthermore, this issur does not need to be a psak halacha from a posek, any different than one needs to ask a shailoh if it is permissible to eat a ham sandwich. As for the sandwich, once one knows it is chazzer, the issur is open in the Torah. Same here.