@22 Sadly, we're all part of a giant experiment. We end up exposed to hundreds of chemicals (which by themselves are supposed to be safe), let them react with each other and see what happens.
It'd be interesting to plot all sorts of ailments versus when certain chemicals entered the marketplace. It wouldn't tell you much, expect that chemicals are making us sicker.
"The Story of Cosmetics", even though U.S. centric, is a great watch. And remember, buy organic!