Comment by blacksmith_tb

It doesn't seem like a surprising result, I agree, though it also wouldn't be too hard for people to wear opaque gloves that covered most of their hands in the machine (unlike the tooth whiteners). My instinct is that if it was extremely bad for us there would be a surprising spike in skin cancers of the hands, but I suppose since hands are exposed to sunlight almost as much as faces, it might be hard to make the connection to nail salons.