So people kind of knew asbestos was harmful wayyy before it mostly stopped being used in 1979 (USA). But, it was still used constantly in many industries and ended up everywhere. What do you think is an example of something we find out is DRASTICALLY harmful 10-50 years from now? My guess would be screen time.
Microplastics is the obvious one. High fructose corn syrup. Palm oil is used in so many things (even juices and biscuits/cookies). Billionaires. Politicians.