I think some of this is related to a certain FDA schizophrenia. My take it that at some point it was decided that it was more efficient / cheaper / better for the FDA to act as a gatekeeper for the public.
I.e A very effectiveness initial scrutiny process for the FDA to say "This is safe, you can sell it to the public" (for drugs at least, and food-related chemicals; I'm admittedly unfamiliar with the tox standards applied to commercial or industrial chemicals) but little done for subsequent discoveries.
Maybe part of that is confirmation bias. "But we ran this chemical through our initial process and it tested as safe. How could it not be safe?"
I.e A very effectiveness initial scrutiny process for the FDA to say "This is safe, you can sell it to the public" (for drugs at least, and food-related chemicals; I'm admittedly unfamiliar with the tox standards applied to commercial or industrial chemicals) but little done for subsequent discoveries.
Maybe part of that is confirmation bias. "But we ran this chemical through our initial process and it tested as safe. How could it not be safe?"