See also http://en.wikipedia.org/wiki/Dose-respon…
Note that while the linear dose-response relationship often postulated to predict deaths from very low exposures has the virtue of being simple, it lacks the far more important virtue of actually being correct. For example:
Vitamin A is required for health. http://en.wikipedia.org/wiki/Vitamin_A_d…
However, if you should ever happen to be up North and have to eat a polar bear to survive, do not eat the liver. It contains enough Vitamin A to kill you.
http://en.wikipedia.org/wiki/Polar_bear#…
"Hunters make sure to either toss the liver into the sea or bury it in order to spare their dogs from potential poisoning".
No linear model can account for this dose-response relationship.
3] The real problem with 2,3,7,8 tetrachloro dibenzo paradioxin is that it is just too blasted thermodynamically stable, and that pretty much any sooty fire where there is much of any chlorine will produce it. This is why incinerators are heavily regulated and heavily instrumented.
Grilling meat produces significant dioxin.
I saw in Nature or Science [15 - 25 years ago] a letter pointing out that [globally] forest fires produce around ten thousand tons of dioxin annually.
Recently the US EPA had forced the US paper industry to spend [collectively] about a billion dollars in capital, and an added quarter billion increased annual cost, to cut their [collective] dioxin emission from around one pound to around one ounce.
When forest fires are dumping ten kilotons annually, one pound is a drop in the ocean !!
Removing that drop lowers the ocean not at all.
That billion dollars of capital and quarter billion dollars increased annual cost could have been used in ways that would have actually made people healthier and safer, instead of being wasted for essentially zero gain. There were far more pressing environmental hazards where that money could have done a lot more good. Or consider how many hospitals those billions could have built and run.