What have we learned from the false heroes of chemistry?

3M was aware as early as 1979 that PFOS & PFOA would bio-accumulate around their production site and, as internal documents show, knew about the toxicity of PFOS as well as PFOA by the mid 80s. The company gradually stopped production as soon as environmental agencies caught on to it, priding itself for its environmentally friendly way of doing business. The fact that concentrations of other, different, but similar compounds keep increasing is extremely concerning. If history is not to repeat itself, regulators and citizens must learn from the past.