How likely is it to have an adverse reaction to green or other color ink in tattooing?

Tattoo: Quite likely especially if you have allergies.

It's rare: The chromium dioxide that makes the green in tattoos is much less troublesome than the red and even the yellow. Don't get inked if you have sarcoidosis. The usual rules apply -- no tattoos until you're 30, and then only if you have wanted exactly that tattoo in exactly that place for five years.

Green reaction: I have never seen an allergic reaction to green while I have seen many to the red color in tattoos.