I want to test the ability of students to read a passage and answer questions about it. Could you please come up with a good question for the passage "In 1982, the US Mint began minting pennies coated in copper but made primarily of zinc. With the new zinc pennies, there is the potential for zinc toxicosis, which can be fatal. One reported case of chronic ingestion of 425 pennies (over 1 kg of zinc) resulted in death due to gastrointestinal bacterial and fungal sepsis, whereas another patient, who ingested 12 grams of zinc, only showed lethargy and ataxia (gross lack of coordination of muscle movements). Several other cases have been reported of humans suffering zinc intoxication by the ingestion of zinc coins."?
A:
Which type of metal does not cause toxic symptoms?