Are you asking just about polymers?
I didn't watch it, but here
is a supposed documentary about the use of PVC and other vinyls for food use. Apologies if it's useless, I couldn't be bothered to download it.
Anyway, there are
concerns about the use of PVC in food applications, and in any case if your intentions are to market a product, you'll probably have to use certified food-grade plastics. Obviously, your material selection depends as much on the actual application as any safety issues, - it's pointless to use a safe plastic if it doesn't fulfil other criteria.
It should be remembered that all
pure polymers themselves are non-toxic, but many additives (colourings, hardeners, stabilisers etc) added during the various manufacturing processes are.