Nickel metal is benign. Oxidized nickel (II) in the salts used in battery chemistry are toxic, carcinogenic [0], and water-soluble. https://en.wikipedia.org/wi

Nickel metal is benign. Oxidized nickel (II) in the salts used in battery chemistry are toxic, carcinogenic [0], and water-soluble. https://en.wikipedia.org/wiki/IARC_group_1_Carcinogens#Chemical_substances https://en.wikipedia.org/wiki/IARC_group_1_Carcinogens#Chemi...