The green guide (from National Geographic) has product reports which tell you about the problems and solutions regarding a vast array of product categories. Nail polish is on the list. As it's summer, I figure it's pertinent because although I don't wear make-up on a regular basis (maybe twice a year), I do like to colour my toenails in the summer. Nail polish, though, is one of the nastiest products on the cosmetics market, because (among other reasons) our nails are so porous and things absorbed through them go straight into the blood stream, and many ingredients in nail polish are toxic. Yikes.
There are other problems, so it's worth a read.
Also, the Environmental Working Group's Cosmetic Safety Database has a list of nail polishes and their hazard rating, as well as whether they do animal testing or have signed the Compact for Safe Cosmetics.
Hence, no more nail polish, unless it's from the "safer products" list(scroll to the bottom for the list) but it's unlikely that I'll bother looking for the products on that list, so I think it's safe to say I'll just avoid nail polish altogether.
~ Lynn