"Reef-safe" sunscreen generally means a formula without UV filters such as oxybenzone and octinoxate, which research has linked to harm in corals; NOAA and the National Park Service favor mineral sunscreens with zinc oxide or titanium dioxide. But "reef-safe" isn't a regulated term, so the only reliable way to check is to read the active ingredients.
If you're heading to the beach, snorkeling or simply trying to make lower-impact choices, here's what the science and the rules actually say, where the research is still unsettled, and how to choose a sunscreen that protects both your skin and the water you swim in.
Key takeaways
- "Reef-safe" and "reef-friendly" are marketing terms with no official definition.
- Oxybenzone and octinoxate are the filters most widely flagged; Hawaii has restricted their sale since 2021.
- NOAA and the National Park Service favor mineral sunscreens with zinc oxide or titanium dioxide.
- A 2022 National Academies report says the effects of UV filters on aquatic life are not fully understood.
- Never skip sunscreen for the reef's sake; cover up with clothing and shade so you need less.
Why sunscreen and coral reefs are linked
Sunscreen washes off. The National Park Service notes that more than 1 million people a year swim in the ocean to explore coral reefs in national parks, and the sunscreen they wear rinses off into the water and onto coral. Worldwide, it estimates that 4,000 to 6,000 tons of sunscreen wash off people into oceans each year. Hawaii's legislature has also found that these chemicals reach coastal waters from swimmers and beachgoers and are not removed by the state's wastewater treatment system.
What the reef-safe sunscreen research found
The study most often cited is a 2016 paper in Archives of Environmental Contamination and Toxicology, led by C. A. Downs, which is archived in NOAA's institutional repository. NOAA summarizes its findings on oxybenzone (also called benzophenone-3) in early-stage coral as four effects: greater susceptibility to bleaching, DNA damage, abnormal skeleton growth, and gross deformities. The authors also found the effects were worse in light than in darkness.
NOAA's National Ocean Service describes a 2013 study on a related compound, benzophenone-2, finding that very low concentrations could quickly kill juvenile corals and cause colorful corals to bleach.
NOAA is careful to note that how these and other compounds affect reefs "remains an active area of research," and that "a more comprehensive ecological risk assessment of all UV filters in chemical sunscreen is needed."
The 2022 National Academies review
That call was echoed in 2022 by the National Academies of Sciences, Engineering, and Medicine, in a review sponsored by the U.S. Environmental Protection Agency. It concluded that "the impact of these filters on aquatic ecosystems is not fully understood" and called on the EPA to conduct an ecological risk assessment of UV filters, starting with high-exposure places such as sites with "heavy recreational use." The report also weighs the other side: regular sunscreen use "has been shown to reduce the risk of sunburn and skin cancer," and the committee was asked to consider concerns that people might use less sunscreen rather than switch filters.
Ingredients agencies flag
Different sources name slightly different lists. Here's how they compare:
| Ingredient | NOAA (National Ocean Service) | National Park Service | Hawaii law (Act 104, 2018) |
|---|---|---|---|
| Oxybenzone | Listed as harmful to marine life | Avoid | Sale restricted |
| Octinoxate | Listed | Avoid | Sale restricted |
| Avobenzone | Not listed | Avoid | Not covered |
| Octocrylene | Listed | Not named | Not covered |
| Benzophenone-1, benzophenone-8, OD-PABA, 4-methylbenzylidene camphor, 3-benzylidene camphor | Listed | Not named | Not covered |
| Nano zinc oxide, nano titanium dioxide | Listed | Not named | Not covered |
| Zinc oxide, titanium dioxide (as mineral sunscreen) | Mineral sunscreen "considered a better option" | Recommended | Not covered |
One nuance worth noting: NOAA's list includes the nano forms of zinc oxide and titanium dioxide, even as it calls mineral sunscreen the better option overall. If this matters to you, look for product information about particle size.
What Hawaii's law does
In 2018, Hawaii enacted Act 104 (Senate Bill 2571), approved July 3, 2018. Starting January 1, 2021, it banned the sale, offer for sale or distribution of sunscreens containing oxybenzone or octinoxate in the state, unless a licensed healthcare provider prescribes them. The law's findings state that "oxybenzone and octinoxate cause mortality in developing coral" and that its purpose "is to preserve marine ecosystems." Products marketed as facial cosmetics are not considered "sunscreen" under the Act.
Why "reef-safe" on a label isn't enough
None of the agency sources we reviewed define "reef-safe" or "reef-friendly," and the National Park Service warns directly: "Sunscreens with the label 'reef-friendly' may still include ingredients that can harm corals." Its advice is to read the active ingredient list rather than relying on the front of the bottle. It's the same problem we describe in what "clean beauty" means: an appealing word with no agreed standard behind it.
How to choose a reef-conscious sunscreen
- Flip the bottle. Check the Drug Facts panel for active ingredients.
- Choose mineral actives. The National Park Service suggests products whose only active ingredients are zinc oxide or titanium dioxide.
- Still meet the skin-protection basics. The American Academy of Dermatology recommends broad-spectrum protection, SPF 30 or higher, and water resistance, and reapplying about every two hours and after swimming. Our sunscreen guide covers this in more detail.
- Cover up so you need less. NOAA and the National Park Service both recommend UV-protective clothing, such as a rash guard, plus a hat and sunglasses. Seek shade in the middle of the day; NOAA suggests between 10 a.m. and 2 p.m.
For a closer look at how mineral and chemical filters differ for your skin, see our mineral vs. chemical sunscreen guide.
What to look for when buying a reef-conscious sunscreen
- Active ingredients: zinc oxide and/or titanium dioxide only.
- Particle size information, such as "non-nano," if NOAA's nano listing concerns you.
- "Broad spectrum" and SPF 30 or higher on the Drug Facts label.
- "Water resistant (40 minutes)" or "(80 minutes)." The FDA requires water-resistant labels to state which, and says there is no such thing as "waterproof" sunscreen.
- A product sold legally where you're going, if you're traveling to Hawaii.
We aren't stocking a sunscreen yet. When we do, it will go through the same review described on our standards page. In the meantime, body moisturizers live in our body collection.
Who should be careful
- Anyone tempted to skip sunscreen for the reef. The National Academies report notes regular use reduces the risk of sunburn and skin cancer. Switch filters and cover up instead.
- Babies under 6 months. The FDA says sunscreen is not recommended for them; keep infants out of the sun, especially between 10 a.m. and 2 p.m., and ask a doctor.
- Sensitive skin. Mineral filters are often gentler, but patch-test any new formula.
The bottom line: "reef-safe" is a helpful idea but an unregulated label. The most dependable approach, according to NOAA and the National Park Service, is a mineral sunscreen whose active ingredients are zinc oxide or titanium dioxide, paired with sun-protective clothing and shade.
FAQ
Is "reef-safe" sunscreen regulated?
Not by any definition in the agency sources we reviewed. The National Park Service warns that products labeled "reef-friendly" may still contain ingredients that can harm corals, so check the active ingredients in the Drug Facts panel. Hawaii's law restricts specific ingredients rather than defining what "reef-safe" means.
Which sunscreen ingredients should I avoid for coral reefs?
Oxybenzone and octinoxate are named by NOAA, the National Park Service and Hawaii law. NOAA's list also includes octocrylene and several other filters, including nano forms of zinc oxide and titanium dioxide, and the National Park Service adds avobenzone. Lists differ, so read active ingredients rather than relying on a front-label claim.
Is mineral sunscreen reef-safe?
NOAA says mineral sunscreen "is considered a better option," and the National Park Service recommends zinc oxide or titanium dioxide. NOAA does list nano forms of both among ingredients of concern, so check for particle-size information if that matters to you. Either way, pair it with clothing and shade.
Is oxybenzone banned in Hawaii?
Yes. Under Act 104, the sale of sunscreens containing oxybenzone or octinoxate has been prohibited in Hawaii since January 1, 2021, unless prescribed by a licensed healthcare provider. Products marketed as facial cosmetics are not considered "sunscreen" under the Act, so check labels carefully before you travel.
Does choosing reef-safe sunscreen actually make a difference?
The honest answer is that scientists are still working it out. NOAA calls the topic "an active area of research," and the National Academies said in 2022 that the impact of UV filters on aquatic ecosystems is not fully understood. Choosing mineral filters and covering up are low-cost ways to reduce what washes off.
How can I protect reefs besides changing sunscreen?
Wear less sunscreen by covering more skin. NOAA and the National Park Service recommend UV-protective clothing such as a rash guard, plus a hat and sunglasses, and seeking shade between 10 a.m. and 2 p.m. You'll still need sunscreen on exposed skin, reapplied about every two hours.
Sources
- NOAA National Ocean Service: Sunscreen chemicals and coral reefs
- NOAA National Ocean Service: Sunscreen chemicals and corals (NOAA studies)
- NOAA Institutional Repository: Downs et al. (2016), Toxicopathological Effects of the Sunscreen UV Filter, Oxybenzone, on Coral Planulae
- U.S. National Park Service: Sunscreen
- Hawaii State Legislature: Act 104 (2018), S.B. 2571
- National Academies of Sciences, Engineering, and Medicine: Review of Fate, Exposure, and Effects of Sunscreens in Aquatic Environments and Implications for Sunscreen Usage and Human Health (2022)
- FDA: Sunscreen: How to Help Protect Your Skin from the Sun
- American Academy of Dermatology: Sunscreen FAQs
This guide is general information, not medical advice. Patch-test new products and ask a dermatologist or doctor about skin or health concerns.
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