Science Natural Science Hawaii Wants to Ban Chemical Sunscreens to Save Its Coral Reefs By Katherine Martinko Katherine Martinko Twitter Senior Editor University of Toronto Katherine Martinko is an expert in sustainable living. She holds a degree in English Literature and History from the University of Toronto. Learn about our editorial process Updated October 11, 2018 CC BY 1.0. US Geological Survey Share Twitter Pinterest Email Science Space Natural Science Technology Agriculture Energy When sunscreen chemicals wash off beach-goers, they bleach coral, stunt its growth, and sometimes kill it outright. If you’re heading to Hawaii, or any other tropical paradise, to soak up the sun this winter, you might want to leave the sunscreen behind. It sounds counterintuitive after years of being told to slather on sunscreen to protect our skin from dangerous UV rays, but now research is showing that human use of sunscreen could be seriously damaging tropical coral reefs. Senator Will Espero presented a bill to the state congress on January 20 that would ban sunscreens containing oxybenzone and octinoxate (except under medical prescriptions) in Hawaii. Espero argued that a ban is crucial to maintaining the health of coral reefs – an tourist attraction on which Hawaii relies. Sunscreens use filters, either chemical or mineral, to block out the sun’s radiation. The chemical filters are most damaging, washing off the skin into the water while swimming, surfing, spearfishing, or even using a beach shower. Researchers have measured oxybenzone in Hawaiian waters at concentrations that are 30 times higher than the level considered safe for corals. According to Hawaii’s Department of Land and Natural Resources: “[These chemicals] cause deformities in coral larvae (planulae), making them unable to swim, settle out, and form new coral colonies. It also increases the rate at which coral bleaching occurs. This puts coral reef health at risk, and reduces resiliency to climate change.” Says Craig Downs of Haereticus Environmental Laboratory in Virginia, whose research on stunted coral growth has heavily influenced Espero's bill: "Oxybenzone -- it kills [coral]. It turns them into zombies if it doesn't kill them outright. It makes them sterile and you do not get coral recruitment." This problem is not unique to Hawaii. Approximately 80 percent of the corals in the Caribbean Sea have died over the past 40 years. While there are many compounding factors, such as temperature anomalies, overfishing, coral predators, coastal runoffs, and pollution from cruise ships and other vessels that affect coral health, the fact that an estimated 14,000 tons of sunscreen wash off annually into the world’s oceans is a serious matter. Not surprisingly, Espero has met resistance from sunscreen manufacturers, such as L'Oréal, which say the evidence is not yet strong enough to justify a ban; but Espero insists the public support is there. Scientific American quotes him: “We have advocates and science on our side. Fishermen, boat owners, sailors, ocean-sports enthusiasts, ocean-tour operators and environmentalists rely on the ocean for recreation and jobs. Opponents will be out there, but supporters as well.” If you’re wondering how not to burn in the sun, check out the Environmental Working Group’s 2016 guide to safe sunscreens, and consider its advice: “Sunscreen should be your last resort.” Use clothing (long-sleeved shirts or special UV blocking clothes), shade, sunglasses, and careful timing to minimize exposure to sunshine.