I'm not sure, but I think that if you have a statement like "Not A Toy- This Product is Not Intended for Children 12 and Under", you don't have to be specific about what could possibly be a hazard.
As long as the items wouldn't normally be thought of as appealing to children, that's all you really need. (well, plus whatever the laws are, if any, for labeling what you make for adults.) But you can't just claim it's not for kids if it really is. Sometimes it's hard to say, it's kind of subjective to assume what any child would or wouldn't want to play with!
http://www.cpsc.gov/ABOUT/Cpsia/faq/faqs.html