In the '70's a pesticide plant in Seveso Italy blew up http://en.wikipedia.org/wiki/Seveso_disa… and sent out a cloud containing dioxin, and a large number of people were exposed.
see http://en.wikipedia.org/wiki/Seveso_disa… from which I quote
"A 2001 study observed no increase in all-cause and all-cancer mortality"
I remember seeing results in Nature and/or Science finding no excess cancers.
From that article it seems that they have since detected some particular cancers that may be more common, but that took until recently to detect, ie, it was not a gross effect, or even an only moderately subtle one. But it also implies that other cancers are less likely. Turns out not to be unprecedented; smokers get lots more lung cancer, but less stomach cancer. Stuff they would have coughed up and swallowed and gotten stomach cancer from they couldn't get out of their lungs in the first place.
4] What lead and/or cadmium compounds are used, for what purpose ? Please provide specifics.
Tin is also quite biotoxic. It is no longer legal to use tin containing paints on hulls to prevent fouling [barnacles etc, which increases drag mightily].
Also note that there are many cadmium plated nuts and bolts out there. In household goods.