I haven’t done my homework but I find it strange that I hear so much about 3M while DuPont seems as bad — or worse — but it could simply be that I’ve read more about DuPont and I’m missing some inexhaustible list of atrocities 3M has committed.
DuPont discovered PTFE while exploring for new refrigerants. It was used in the Manhattan Project because it could resist flourine used in the gaseous diffusion of uranium, then marketed as Teflon after WWII.
3M discovered PFOS while developing rubber that wouldn't degrade when exposed to jet fuel, then marketed it as Scotchgard.
I shudder when I think about how I used to coat every new couch and my shoes with this stuff. No mask when applying. Skin contact for years…