all metals that bind to sulfur well are to some degree poisonous. these are lead, mercury, thallium, some platinides (in salt form), arsenic, and also copper, but less than others. some metals have other mechanisms of toxicity, like nickel, hexavalent chromium, cadmium, beryllium or barium. some of these accumulate in brain or bones, and some don’t. some are more toxic when inhaled like zinc or chromium