I'd have guessed this was "common sense", but here you are:

http://en.wikipedia.org/wiki/Marijuana#Long-term_effects

Anyway, my point is that the argument that "marijuana isn't toxic so it should be legal" isn't valid. First, because it is toxic. Also, because it isn't that relevant: there is similarly toxic stuff that is legal.

> I guess everything is toxic to a certain degree, even water is toxic if you swallow enough of it.

Well, I'm talking about normal effects of normal doses.

I didn't see anything in the what you linked to that stated that marijuana was toxic. A lot of "might be" linked "to certain things" but nothing substantive.

More people die each year from OTC painkillers (aspirin, tylenol, advil) than they do in deaths caused by marijuana (0).

http://drugwarfacts.org/cms/?q=node/30

Mikuriya, T.H. "Historical Aspects of Cannabis Sativa in Western Medicine," New Physician, 1969, p. 905.

Grinspoon, Lester. Marihuana Reconsidered. Cambridge: Harvard University Press, 1971.

Nadelmann, Ethan A. "Drug Prohibition in the United States: Costs, Consequences, and Alternatives," Science, Vol 245: 943, 1 September 1989

There don't seem to be many toxic effects in that link. A lot of correlation, but not much causation.