I can't believe stuff like this actually happens anymore
Apparently Yushchenko was poisoned with this dioxin. The analyst CNN dug up at 4:00pm on a Saturday apparently didn't really know that much about dioxin. He said that it is a herbicide, but in fact it is only a very famous contaminant of a herbicide, namely it famously contaminated batches of agent orange in Vietnam. Here is a study from 2001 with graphic photos of the effects of high levels of dioxin exposure (pdf here). The scars on the patients closely resemble Yushchenko's disfigurement.
I cannot believe that anyone could do something like this to themselves. Not only is dioxin poisoning incredibly (and invisibly) painful and disfiguring, but it will shorten the lifespan by drastically increasing the chance of developing cancer.