You wear sunscreen when you go outside to protect your skin. You reapply after you take a dip in the ocean or lake because the sunscreen has washed off. Even underwater, you aren’t protected from the sun’s rays: up to 70% of UV intensity hits your skin when you’re swimming in waters where you can still see light. Thank goodness for sunscreen, right?

For you, yes. But that sunscreen that’s protecting your skin might actually be extremely harmful to the plants and animals you’re sharing the ocean with.

A 2015 study conducted in Hawaii and the U.S. Virgin Islands, indicates that certain compounds in a number of popular brands of sunscreen – including products from Banana Boat, Coppertone, and Neutrogena – are leading to increased instances of coral bleaching among these important nursery habitats.

The compound, Oxybenzone, is one of the active ingredients in sunscreen lotions that protects your skin against the damaging effects of UV light (Downs, et al., 2015).

But the compound that acts to shield your skin against the sun’s rays, is the same one that is toxic to coral reefs. Oxybenzone is a photo-toxicant, meaning that it makes coral more sensitive to damage from the sun. The chemical, which has been shown to increase the rate of damage to DNA in species ranging from fish to mice and rats, is detrimental to larvae or newly settled individuals.

In small doses, this might not have significant effects; however, it’s estimated that anywhere between 6,000 and 140,000 tonnes of sunscreen with the phototoxic compound are released into important coral reef habitats every year.

This comes from a number of diverse sources: the compounds are found in a number of personal care products, including lip balm, perfume, hairspray, mascara, and shampoo and conditioner; Oxybenzone has even made its way into household products like soaps and bath oils. Thus, it’s not just a matter of contamination from scuba divers and snorkelers: contaminants in discharged wastewater from residential, municipal, and ships is more than enough to have significant impacts on the species.

Of course, it’s not all doom and gloom; a number of major brands have committed to making their products environmentally friendly, and there are a lot of options for you to choose from. The Environmental Working Group (EWG) came up with this handy list showing all the friendly sunscreens you can purchase, which they update every year. Truth In Aging came up with a list of moisturizers for your face that don’t contain the compound. And WebMD has this easy-to-understand overview of oxybenzone and how to avoid it.

More Articles Like This

Swim Guide
is supported by
* The RBC Foundation

Swim Guide shares the best information we have at the moment you ask for it. Always obey signs at the beach or advisories from official government agencies. Stay alert and check for other swimming hazards such as dangerous currents and tides. Please report your pollution concerns so Affiliates can help keep other beach-goers safe.

Swim Guide, "Swim Drink Fish icons," and associated trademarks are owned by SWIM DRINK FISH CANADA.| See Legal.