Where would you like me to start? Perhaps asbestos, it's well known and well documented. 2000+ years ago the Romans were well aware of its dangers and called is effects 'the wasting disease', that's why they only sent slaves and prisoners to asbestos mines.
It was then the subject of several Admiralty inquiries in the late 19th and early 20th Centuries that came to the conclusion that it was dangerous and significantly shortened lives but the reports were overlooked as those lagging pipes on ships were expendable, getting ships ready for war wasn't. And we are still dealing with the stuff 100+ years on.
We could end with the dangers of social media and AI, but the populous at large is so enamored with them it can't even yet see the dangers let alone consider regulating them.