Based on the documentation provided by a sibling comment, I think the answer is that ingestion of the metallic form is not so bad. It's some nickel compounds an

Based on the documentation provided by a sibling comment, I think the answer is that ingestion of the metallic form is not so bad. It's some nickel compounds and inhalation that are particularly dangerous. Again, the document posted by a sibling (https://rais.ornl.gov/tox/profiles/nickel_and_nickel_compounds_f_V1.html https://rais.ornl.gov/tox/profiles/nickel_and_nickel_compoun...) likely contains all the detail you could wish for. Also, nickels are about 75% copper.