Beyond the Beach Bag: Tracing Sunscreen’s Journey to the Reef

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The scene is familiar: it’s a hot summer day at a beach and the reassuring smell of sunscreen wafting from the bottle. Most people think of sunscreen as a protection for our skin when the UV is high but many don't know what happens once the SPF washes away. What was once on your face can end up in the coral reef and cause a lot of harm. 

The problem begins when the sunscreen bottle is opened and you apply it on your skin. After that, when showering or swimming it can send the sunscreen down drains and into waterways. Around 25% to 50% of sunscreen washes off during swimming or water activities. The rest is removed when showering which also eventually ends up in the ocean (Brown). Once the sunscreen is in the water, it doesn’t just vanish. Many formulations contain chemicals like oxybenzone and octinoxate, which can cause deformities and damage the coral DNA (Olson). These substances are small enough to pass through wastewater treatment systems, meaning they can slip from urban plumbing to rivers, estuaries, and eventually the ocean. Coral reefs are already harmed due to warming waters, pollution, and overfishing. On top of that, sunscreen chemicals tip the scales. 

In tropical locations like Hawaii and Palau, sunscreen concerns have become so serious that sunscreens are now banned. Paula banned sunscreens that contain chemicals like oxybenzone and octocrylene, which are known to harm coral reefs up to 5 kilometers away, to protect its marine environment (Carreon). Scientists have found that even a small amount of sunscreen can damage coral DNA and hinder their growth while increasing bleaching. And given that these locations are full of tourists especially during the summer, the cumulative effect can be significant. 

In these severe situations, using “reef-safe” sunscreens that use non-nano zinc oxide or titanium dioxide can allow us to protect our skin while protecting marine life. Likewise, wearing UV-protective clothes so that sunscreen use can be decreased. 

Sunscreen pollution is not talked about much as plastic pollution but the impact of it is as concerning. By making smart choices in our next summer holiday, it can help keep coral reefs vibrant for the future. 

Works Cited

Brown, Elizabeth Anne. “Is 'Reef Safe' Sunscreen Really Better?” The New York Times, 19 May 2025, https://www.nytimes.com/2025/05/19/climate/sunscreen-reef-safe.html. Accessed 10 August 2025.

Carreon, Bernadette. “Palau plans sunscreen ban to save coral.” https://phys.org/news/2018-11-palau-sunscreen-coral.html. Accessed 10 August 2025.

Olson, Danielle. “The Truth About Corals and Sunscreen.” Smithsonian Ocean, https://ocean.si.edu/ecosystems/coral-reefs/truth-about-corals-and-sunscreen. Accessed 11 August 2025.