Evaluation of chemical exposures generated from n-free nail polishes

Nail polishes contain over a dozen chemical compounds, including chemicals that can cause adverse reproductive outcomes and pose a risk to the high proportion of nail salon workers who are women of childbearing age. Consumer demand has resulted in a shift toward more natural products, with manufacturers attempting to remove harmful ingredients (n-free products). Many products that claim to have eliminated toluene, formaldehyde, and dibutyl phthalate (DBP) are labeled as "3-free"; however, studies have found these products often contain higher concentrations of toluene and DBP compared to products with no such claims. Products used only at salons are not required to list ingredients, leading to uncertainties as to the exact chemical composition and potential exposures. A better understanding of chemical exposures associated with nail polish products is necessary to understand potential worker exposures and develop effective control options. This study evaluated chemical exposures generated while painting nails with 20 n-free polishes using real-time and time-integrated air sampling. Total volatile organic compounds (TVOCs, PID, ION Science Inc.) and 22 individual compounds (FTIR, Gasmet Technologies) were measured in the breathing zone of the manicurist while two coats of polish were applied to artificial nails on a manikin in an exposure chamber and for 2 hr afterwards. Formaldehyde and toluene were measured in all polishes using the real-time FTIR, despite all claiming to be 3-free. Normalized geometric mean (GM) formaldehyde exposures from the FTIR ranged from 0.021 to 0.273 ppm/g, GM toluene exposures ranged from 0.068 to 0.534 ppm/g, and GM benzene exposures ranged from 0.076 to 0.752 ppm/g. Notably, formaldehyde, toluene, and benzene exposures did not significantly differ between different products. Neither DBP nor triphenyl phosphate (TPhP) was detected in any of the polishes. This study highlights that despite industry claims, n-free polishes may still contain chemicals associated with negative health effects and that more studies are necessary to understand the true chemical exposures of nail salon workers.