God damn you people and your inability to search these boards or Google extensively enough on your own to answer your own questions. (Except Beachguy and I suppose 1234abcd)

Graph you're on the right track too. I believe the polonium 210 and lead 210 in tobacco smoke plays a major role in the development of cancers. These are both radioactive, they emit alpha particles and it is no surprise that long-term exposure to alpha particles internally will cause tissue damage. Above all polonium 210 is the only component of tobacco smoke demonstrated to cause cancer alone when inhaled in lab tests.