Reef safety has become a significant consideration in sunscreen formulation, and for good reason. An estimated 14,000 tons of sunscreen wash into the ocean every year, and we now have robust data on which UV filters contribute to coral bleaching and marine toxicity, and which ones don't. In this article, we break down the science behind reef safety, explain which UV filters are harmful and show how to identify authentic reef safe sunscreens.
The chart below shows the list of sunscreen filters considered not to be reef safe. Even if just one of them is in your sunscreen, your product is NOT reef safe.
The current challenge is that 'reef safe' isn't a regulated term. Any product can carry the label regardless of what's inside. This makes ingredient literacy essential - understanding what each UV filter does, both on your skin and in the water, is the only reliable way to make an informed choice.
The Filters With Documented Harm
Oxybenzone and octinoxate are now banned in Hawaii, Palau, the US Virgin Islands, and parts of Mexico. The bans followed research demonstrating that oxybenzone causes coral bleaching at concentrations as low as 62 parts per trillion, along with DNA damage and reproductive disruption in coral larvae. Octinoxate shows similar effects.
Several other legacy filters raise ecological concerns:
These aren't theoretical risks - they are documented in peer reviewed ecotoxicology studies.
The Filters That Pass Ecological Testing
Non nano zinc oxide and titanium dioxide remain the most established reef safe options. As mineral filters with large particle sizes, they don't penetrate coral tissue or bioaccumulate in marine organisms. They've been in use for decades with no evidence of reef toxicity.
Among newer generation chemical filters, bemotrizinol (BEMT), bisoctrizole (MBBT), and DHHB have been evaluated against coral, crustaceans, fish, and algae. The findings are consistent: no significant biological effects at environmental concentrations. These filters offer broad spectrum protection without the ecological footprint of their predecessors.
Making Sense of It All
When formulating sunscreens, I consider both human safety and environmental impact. The two often align - filters that raise concerns about systemic absorption or endocrine disruption tend to be the same ones causing problems in marine ecosystems. Newer generation filters were developed with both considerations in mind.
For those who want to verify their sunscreen's reef safety, we've built a Reef Safe Sunscreen Checker on the CHOSEN site. It's updated regularly with the latest ecotoxicology data and lets you look up any UV filter to see its marine impact profile.
Protecting your skin and protecting the ocean aren't mutually exclusive. It's simply a matter of knowing which filters do both.