It's more a matter of what our weaknesses are; you stop our ability to saaaay, break down acetylcholine, and we're in deep DEEEEP trouble.
Then again, a lot of the toxins you'd be looking at are also carcinogenic
Anyway, inorganic usually means that it's interfering with enzyme pathways one way or another, either through inhibition (usually more toxic) or excitation. http://en.wikipedia.org/wiki/Aflatoxin
is a good example of something a little different and organic.
There are relatively limited ways that inorganic substances hurt us; they need to somehow accumulate and damage us that way, or they do their damage during an attempt at metabolism... so.. enzymes.