PFAS chemicals are in (almost literally) everything.

Yes, this is more or less the circumstance we arrive at when the burden of proof for consumer safety is on injured parties to prove the particular thing unsafe, or its use negligent after the fact, in courts against often powerful corporations with lots of money to spend defending themselves, as opposed to the burden being on would-be sellers to prove its use safe and environmentally responsible before bringing it to market.

I appreciate your post, it really is informative, and it explains how problematic it will be to connect injured parties with the people that harmed them, how now that some people depend on those things and will accept no substitute and will continue emitting more of it into the environment, that the rules as they are don't provide real remedy or solutions for problems that were perfectly legal to create and everyone involved did nothing wrong.

That right there, really, prompts the question- would we really be that much worse off if we had consumer safety rules that put the burden of proving a product or technology's safety and sustainability on the seller, or on some sort of product safety testing system?

If that were to mean industrial chemicals had to undergo trials or studies in the way that pharmaceuticals do, sure there probably would be fewer new things. OTOH if there had to be even the most-rudimentary plan for the lifecycle of a product up front, maybe we wouldn't have millions of tons of discarded plastics or forever chemicals in the environment that everyone knows there's no money to clean up (because our system protects those that profit by externalizing costs).