Oxidized copper cannot be used for this, so it is possible to be deficient in copper yet toxic with oxidized copper.
Only NAC and Moly work on oxidized copper..but unlike binding fresh copper with sulfur which makes it available to the body oxidized copper cannot be reused and must be excreted.
See Hulda Clark on copper toxicity and sources like pipes, but I would add the new chlorine chemistry used in the water supply to that...