A laboratory study of chemicals in nail products and exposure assessment using USEtox

Nail products contain many chemicals that serve a variety of functions and many of them are potentially harmful to product users. To better understand potential exposures to hazardous chemicals in nail products, in 2019, the California Department of Toxic Substances Control (DTSC) analyzed 178 nail products from 21 product types for 52 organic chemicals. The results of this analysis were used to evaluate the accuracy of ingredient labels and marketing claims, as well as to estimate the exposure and potential risk to consumers and nail salon workers using the USEtox model. We detected 29 chemicals, 24 of which are listed by various authoritative organizations as concerning. Several highly concerning chemicals were detected, including methyl methacrylate, formaldehyde, and toluene at maximum concentrations of 8760, 15,600, and 187,000 μg/mL, respectively. Ingredient labels are sometimes inaccurate, with approximately 92% of the tested products containing at least one chemical not listed on the ingredient label. Some products even contained ingredients not listed on labels at concentrations above 10,000 μg/mL. In terms of marketing claims, products which were marketed to children did not contain fewer or lower levels of harmful chemicals than other products. Our USEtox modeling revealed a negligible noncancer risk from home use of a single nail product every 2-3 days. However, the exposure and health risks to nail salon workers and consumers who use multiple products would be considerably higher and are therefore more concerning. This study highlights the need for full ingredient disclosures to help product users identify hazardous ingredients in nail products.