Although it's unlikely, it remains possible that women could develop skin cancer from too much exposure to ultraviolet (UV) light while their nail polish or gel manicures dry, and there have been a few rare case studies where women did develop non-melanoma, squamous cell skin cancer on areas of their hands that were repeatedly exposed to UVA light used in nail salons. To get a better sense of the possible danger, researchers from Georgia Regents University did a random sampling of lamps in 17 nail salons to see how much UV radiation is emitted when nails are drying. They found a wide variation ranging from “barely” to “significant,” said study lead author Lyndsay R. Shipp, but reported nothing to warrant anything more than caution. Previous studies have noted that the exposures to salon lamps are likely not significant contributors to increased risks of skin cancer, and Shipp notes she uses the UV machines at the nail salon every few months and will continue to do so. “You can get that amount of exposure when driving down the road in your car,” she told The New York Times.
Deborah F. MacFarlane, and Carol A. Alonso, “Occurrence of Nonmelanoma Skin Cancers on the Hands After UV Nail Light Exposure,” Archives of Dermatology, 2009;145(4):447-449. doi:10.1001/archdermatol.2008.622.
Lyndsay R. Schipp et al, “Further Investigation Into the Risk of Skin Cancer Associated With the Use of UV Nail Lamps,” JAMA Dermatology, doi:10.1001/jamadermatol.2013.8740