In three years as a firefighter / EMT I have probably been on two medical calls where the patient's chief complaint is related to MJ, and both times it was a 15 y/o kid who smoked for the first time and had anxiety. On the other hand, I'd say roughly b/w 60% - 75% of medical responses are directly or indirectly related to alcohol.
I don't smoke pot and I'm not advocating its use, but I do think its pretty clear that as far as its effects on public health and welfare, alcohol is much worse than pot.