For most people, a trip to the beach involves slathering on a thick layer of sunscreen to protect against sunburn and skin cancer. However, savvy beachgoers know to reapply sunscreen every few hours because it eventually washes off. Now researchers, reporting in ACS’ journal Environmental Science & Technology, have detected high levels of sunscreen chemicals in the waters of Shenzhen, China, and they also show that the products can affect zebrafish embryo development.