Hottest take and speculative: Covid.

And it kind of depends on how you think about the scale of impacts. Aspestos is horribly damaging for a few people directly exposed. The rate of exposure to covid is orders of magnitude higher.

I think we've really only begun to see the long term impacts, and we know already of many of the long term issues related to decline in cognitive abilities, heart issues, all kinds of other stuff. But we right now, only know the small "near tail" behavior of those issues. It will take decades to find the "long tail" behavior of the disease.

So if asbestos exposure is 100x as damaging as covid exposure, say.. but 10,000x as many are exposed to covid... its overall impact is 100x that of asbestos.