There was a grad student who made a ton of different dioxin analogues in grad school (circa 1957) was still alive and well, last I heard, although he suffered from severe chloracne.
It's not readily metabolized by mammals and mainly concentrates in the liver. It'll probably be a while until he starts to recover. Fortunately, everything I have read seems to suggest that dioxin isn't especially lethal to humans (although it's 10,000 times more lethal to mice than cyanide is).
Mitch is right, I doubt we've seen the last dioxin poisoning, especially now that it is back in the spotlight. If you didn't know, TCDD ("dioxin") was found to be a significant impurity in a lot of the "Agent Orange" that was produced during the Viet Nam war and then caused a lot of problems for those who were exposed. It doesn't seem that it causes birth defects and the like in humans (at least the humans exposed to Agent Orange in Viet Nam), although it causes severe birth defects in rats.