@Wen "most dangerous"? Not if you consider acute toxicity. Perhaps "most insidious" -- alongside dioxins etc PAHs from burning plastic waste, especially PVC. eg #Ohio_train_derailment and badly regulated waste incineration everywhere.

People in industry [me too] used to be breathing fluorinated solvents in extreme doses -- even washing hands in it, in the late 70s - 80s... some actually smell very pleasant and were thought to be so harmless! Millions cooking in PFAS-primed PTFE pans, wanting to avoid aluminium with its suspected Alzheimers connections etc. I'm still alive, albeit with possibly related health issues which I've managed to stay 1 step ahead of so far. Far worse insidious poison was lead measurably impacting intelligence, in petrol and avgas, which society has managed to deal with though effects persist.

What alarms governments most, I suspect, are the effects on reproduction as PFAS build up. On top of all those who dont want to inflict a climate-hell on potential children, those whose reproductivity is impacted by chemical toxicity. No humans left to govern! But heh, #degrowth!