I have the Sun Art paper from a different source and the package says 6+. I think that's got a lot more to do with the ability to follow instructions than with safety. I totally agree with bdial that as long as he doesn't eat it and washes his hands after handling a wet print (if he does that), that it should be fine. I have a two year old and I wouldn't even think of doing this with him because his attention span is no where near long enough.