Yeah, chromium and nickel, two of the chief components that put the stainless in stainless-steel, are rather toxic in most/all oxidation states (Cr3+ is weirdly

Yeah, chromium and nickel, two of the chief components that put the stainless in stainless-steel, are rather toxic in most/all oxidation states (Cr3+ is weirdly biologically necessary but toxic in high doses). Their refining process is pretty nasty too - lots of cyanide / carbonyl (monoxide) complexes, and mining is just generally filthy. Automation and cheaper electricity would drive down the cost of recovering metals from aqueous waste.