Because modern CR1216 batteries do not contain mercury, cadmium, or other hazardous metals, they are poisonous.
CR1216 batteries, on the other hand, are little, bright items that can be ingested by dogs or children; when they come into touch with human fluids, they can produce electrolysis, which can be fatal to living tissue.
Although CR1216 batteries do not do as much damage as larger ones such as CR2032 cells, they are still dangerous, which is why so many CR and other comparable batteries are packaged in 'pets-safe' or 'kids-safe' containers. However, if something like this occurs, make sure to contact local emergency services right away and follow their advice.