[mateo1]

That's because these are generally valid arguments. The phrase "the dose makes the poison" did not just occur in someone's head for no reason.

There's a couple things to note about "forever chemicals":

They're around "forever" because they are extremely unreactive. The concentrations the public is concerned about are ridiculous. With such small concentrations, huge timescales for the cause-effect chain to take place and countless confounding factors in between it's basically impossible to make the bold claims the general public makes.

That being said: Workers are exposed to much higher concentrations and they should have been protected from it. New chemicals shouldn't be used as widely as they do by simply assuming they're safe. There are uses (like cosmetics etc) were no risk is really warranted so they should be more restricted with what they use.

At the end of the day though, when you ban something you need to really understand and take into consideration what kind of damage you'll do to people by banning a substance and all the products that depend on it vs. what kind of damage the substance will do. You can't pretend that you can just ban a whole class of really important compounds without any societal side effects.

And that's coming from someone who's really concerned about dangerous chemicals. If you know chemistry, and look around you, you can tell there's a lot more dangerous issues than PFAS that aren't being tackled and nobody seems to care about. Primarily how nobody seems to check what's really included in tons of "cheap" (in terms of manufacturing, not always of price) imported cosmetics, personal hygiene products and parapharmaceuticals.

People are buying protein powders and supplements of unknown producers, raw materials and manufacturing methods by the kilos, plastic cooking utensils from the internet and boil/oven bake them with their food, buy sketchy adhesives for their PVC water pipes, and then complain about some 1ppt concentration of inert chemicals in their drinking water. I understand how the public is easily swayed on things that are technical, and I am happy with people being aware of potential dangers, but the focus is really misplaced on something that looks new, scary, unsolvable and interesting instead of tackling the old, boring but important and serious issues we come across every day.

[Goronmon]

The phrase "the dose makes the poison" did not just occur in someone's head for no reason.

What dose of PFOA/PFAS is harmful instead of harmless?

[mateo1]

What dose of any substance is harmful instead of harmless? Is this a philosophical question or a practical one? If it's a practical one, we don't know, because if there are any effects they're too weak to infer with certainty. Unlike for example those of benzene in your sunscreen or acne products, or flame retardants in your furniture.

[Aloisius]

For PFOA, based on animal trials, somewhere above 10–70 ng/kg body weight-day.