Makeup wearers may be absorbing and ingesting potentially toxic per- and polyfluoroalkyl substances (PFAS), according to a new study published today in Environmental Science & Technology Letters. The researchers found high fluorine levels—indicating the probable presence of PFAS—in most waterproof mascara, liquid lipsticks, and foundations tested. Some of the products with the highest fluorine levels underwent further analysis and were all confirmed to contain at least four PFAS of concern. The majority of products with high fluorine, including those confirmed to have PFAS, had no PFAS listed on the label.