A multitude of undisputed scientific studies over the past 20 years demonstrate that the chemicals oxybenzone and octinoxate found in some SPF sunscreens are toxic to corals and other marine animals. They threaten the overall health of coral reefs by harming and killing coral larvae by inducing gross deformities, cellular degradation and genetic damage.

Exposure to oxybenzone and octinoxate makes coral more susceptible to bleaching at lower temperatures, and reduces the resiliency of a reef and its ability to recover from the impacts of other environmental hazards like sedimentation and climate change. Its greatest ecological threat is that it will prevent a reef from recovering if these chemicals continue to taint a reef area.

We all know of reefs that looked good 30-40 years ago, but now are denuded and desolate: Hanauma Bay, the west coast of Maui and Captain Cook Monument are just a few prime examples.

Again undisputed is that oxybenzone and octinoxate are poisonous to more than just corals. They are noxious endocrine disruptors that will feminize male fish and cause deformities in developing fry, threatening fish populations by reducing reproductive success. Both chemicals are also highly toxic to algae (limu) and sea urchins. Both chemicals will bioaccumulate in organisms, and can reach extremely high levels in edible fish (kumu, uhu), cetaceans (dolphins), shellfish and limu.

You can find these chemicals in the water almost everywhere you go swimming in Hawaii. They come not just from swimmers, but our sewage, which is loaded with these and other personal care product chemicals. In less than 30 minutes after applying an oxybenzone sunscreen to your skin, you can detect it in your urine. Everything that comes off of us or out of us goes back to the ocean.

It is estimated that over 500 tons of sunscreen pollute the waters surrounding Hawaii. With the 2,600 swimmers per day that visit Hanauma Bay, we calculate that over 150,000 pounds of sunscreen pollute Hanauma’s waters, of which is 6,800 pounds of oxybenzone/octinoxate a year. Hanauma Bay is Hawaii’s first Marine Life Conservation District and one of Hawaii’s 12 Class AA marine embayments under the Federal Clean Water Act. Why do we allow this water to be so polluted? We can — and should — do better to protect and preserve these fragile marine ecosystems.

By threatening our coral reefs, these chemicals also threaten our livelihoods, our businesses, our traditions, our very way of life. Without the reefs, we will experience increased coastal erosion, reduction in viable fishing and collection areas, and a frenzied intensity of tourists concentrating in the last vestiges of good reefs – ensuring that these reefs also die.

Residents of Hawaii have the right and responsibility to determine what is best for Hawaii, and banning reef-toxic chemicals in sunscreen is something effective we can do today — right now — to help improve the health and resiliency of our fragile coral reefs.

Lisa Bishop is president of Friends of Hanauma Bay and a Hawaii Reef and Ocean Coalition member; Craig A. Downs is executive director of Haereticus Environmental Laboratory.