Mothballs in the pantry: is it safe to keep food there? My roommate put some mothballs in the pantry and when I came home and saw them, I took them out.

They were probably only there for a few hours, but is it safe to store food in there?  Should I throw out the food that was in there together with the mothballs?  I'm leaning towards 'when in doubt throw it out' but I'm unsure whether that is overkill in this case.
Mothballs work by sublimating (evaporating) a toxic substance into the air. That substance, be it para-dichlorobenzene or napthalene, recondenses on whatever else is in the area around them, and makes those objects toxic to moths etc.
However, the sublimation takes a long time. You can leave mothballs in a closet for months, and still not see very little weight loss in the balls themselves. That means that not much will come off in 'a few hours' to wreck your food.
Tell your roommate that a pantry is not a good long term storage spot for mothballs, but eat the food with confidence. It hasn't had time to get contaminated.