There isn't anything conclusive to show it causes physical damage as tobacco does (which used to be the claim.. actually "worse" than tobacco, even, it's been said). And no need to wait for our hippies to age more before we can know, since other cultures have been using much longer than us.
We do have a problem with lazy growers being duped by insects, though, which often makes for product contaminated with pesticides. In the "clone" market, which is huge among growers, spidermite treatment has become the main threat to safe weed. The ignorant ass grower, instead of treating new clones in a separate area (while they're still tiny and due to outgrow all current mass), will be caught at flowering time with an invasion of mites. Then the stupid lazy shit will begin soaking the entire plant, daily, and will call it a success upon selling, just the same.
Any future problems we may see in this country, will be from pesticide residues and whatever backdoor-bullshit the corporations will do after stealing control and raping the world for its valuables.
