Well I stumbled across this information today and i dont know if it is old or not but i though i would let you guys know http://www.marijuana.com/medicinal-marijuana/11006-marijuana-vs-tobacco-tars-not-so-bad.html Read this article, it is very interesting. basically it is about the Radioactivity, not tar, that is associated with the growing of tobacco and what really causes lung cancer from smoking. read up!