To continue from my other comment, it's not the tar or chemicals in the cigarettes that cause the cancer. Its the apparatus. Same for marijuana. Smoke it from any sort of paper or parch? Carcinogens. Smoke it from glass? Carcinogens. From plastic bottles etc? Carcinogens. Not to mention other latent chemicals used in the process of making the plastic bottle. No matter what, if you're smoking something, you're killing yourself. The problem I have with stoners? They will be diagnosed with cancer, and try to blame it on everything but the drug they so fervently rely on. Which leads me to addiction but I'm not getting into that with a stoner...