Cannabis and Tobacco Smoke Are Not Equally Carcinogenic
Robert Melamede, "Cannabis and tobacco smoke are not equally carcinogenic," Harm Reduction Journal 2, issue 21 (October 18, 2005).
U.S. government officials frequently claim that marijuana smoke has more cancer-causing tars than cigarette smoke. But such statements are misleading, because they ignore critical data, much of which is explored in this article by Robert Melamede, chair of the Biology Department at the University of Colorado, Colorado Springs. Unlike tobacco, marijuana use has never been causally linked to higher rates of lung cancer or other smoking-related cancers, and several compounds in marijuana have been shown to actually kill cancer cells while sparing healthy cells.
Free full text available at: http://www.harmreductionjournal.com/content/2/1/21.