Otherwise, we get vendors poisoning us for decades, and then whoopsie-daisies pleading ignorance. And even when they get held accountable (almost never), the value that remains in the vendor is insufficient to compensate for the damage inflicted on us.
Heads I lose, tails they win.
What is the actual bar?
The intended use of leaded gasoline is burning it and putting lead in the air.
The intended use of asbestos is as an inert fire-retardant layer. It's safe in that context. Where it's not safe is in all the work that goes into building, or tearing down that layer.
The intended use of BPA was putting it into 'microwave safe' plastic containers, where it leeched into food.
Bleach is safe to handle (carefully), but not safe to drink.
(when inhaled)