A roomie of mine in college fell victim to household spice smoking. Or rather, his bag of dried basil, oregano, and thyme did. He came home one night intending to cook up some pasta and mix the herbs with some olive oil for pesto. The bag, which had been in the pantry, was missing. Turns out that another roomie had mistaken the stuff for wacky weed and smoked it.
I don't know what's more frightening, the fact that dried pesto mix could be mistaken for weed, or the fact that the smoker didn't care.