On January 1, 2021, Hawaii became the first U.S. state to ban the sale of sunscreens containing oxybenzone or octinoxate. The law had been signed in 2018. Since then, other islands have followed suit, and a city in Florida had its ban overturned before it even came into effect.
These decisions are based on concerning laboratory studies. They also rely on a lot of uncertainty, and it is this mixture that we untangle here, separating what science has established, what it still suspects, and what laws actually impose, date by date.
No brand is mentioned here. To choose a product, our guide on non-toxic sunscreen for corals and brands to compare takes over.
This article informs; it does not replace the advice of a physician competent in diving medicine.
What is the criticism against oxybenzone and octinoxate?
In the laboratory, these two chemical UV filters have been linked to bleaching, DNA damage, and deformities in young corals. NOAA, the U.S. oceanic agency, places them on its list of skincare ingredients likely to harm marine life, alongside eight other substances.
The list is surprising. It includes octocrylene and two camphor derivatives, but also titanium dioxide and zinc oxide in nanoparticle form.
In other words, “mineral” does not mean exempt from concern.
The suspected mechanism involves water. When you swim or rinse in the shower, part of the sunscreen goes into the environment, directly into the sea or later through wastewater. In a shallow, heavily frequented, and poorly mixed site, concentrations can rise. Elsewhere, they dilute quickly. Yet, these two situations are often mixed in popular articles, with the same alarmist tone and figures cited without context.
Why hasn’t science made a definitive judgment yet?
Because laboratory measurements and field measurements do not yet tell the same story. The report from the U.S. National Academies of Sciences, published in 2022, confirms that UV filters are detected in water, sediments, and tissues of aquatic animals. However, it judges their real impact on environments as poorly understood.
Experiments often expose coral fragments or larvae to fixed doses, in tanks, over a short duration. In the sea, the dose changes with tides, swell, number of bathers, and distance from wastewater discharge. Corals also endure heat, sediments, and other pollutants. Isolating the effect of a single filter becomes very difficult. The very low toxicity thresholds circulating online come from these tank exposures.
But this uncertainty does not mean exoneration. The committee asks the U.S. Environmental Protection Agency to conduct an ecological risk assessment of UV filters, prioritizing areas with intense swimming and wastewater inflows. It also reminds of the other side of the balance. Sunscreen protects against skin cancer.
Marine heatwaves remain linked to major bleaching episodes, as our overview on threats to corals recalls.
In short, a serious signal, without field measurements yet allowing quantification of the sunscreen share.
What did Anses conclude for overseas reefs?
Anses, with the French Biodiversity Office, evaluated in 2023 the chemical risks weighing on coral reefs of Guadeloupe, Martinique, Réunion, and Mayotte. Five UV filters stand out as risky: 2-ethylhexyl salicylate, enzacamene, octocrylene, benzophenone-3 (oxybenzone), and octinoxate.
The agency presented this work to the public in July 2025. It does not only concern sunscreens. Metals and pesticides are part of the assessment, and about half of the substances evaluated present a risk to reefs, a result the agency considers probably underestimated.
However, Anses does not stop at the observation.
It requests that products containing these substances not be marketed as safe for the marine environment. The message targets directly claims like “reef safe.” France is also preparing a restriction dossier on octocrylene with the European Chemicals Agency. The agency’s publication cites no European ban currently in force to protect corals. Such procedures take time.
Where are these filters banned, and since when?
Bans remain local. Hawaii, Palau, Bonaire, the U.S. Virgin Islands, Maui County, and Thailand’s marine national parks each apply their own list, with rules effective between 2020 and 2022. Key West had voted its ban, but a Florida law overturned it before application.
| Location | Targeted Substances | In Effect Since |
|---|---|---|
| Palau | About ten substances, including oxybenzone, octinoxate, and octocrylene | January 1, 2020 |
| U.S. Virgin Islands | Oxybenzone, octinoxate, octocrylene | March 2020 |
| Hawaii (State) | Oxybenzone, octinoxate (sale and distribution) | January 1, 2021 |
| Bonaire | Oxybenzone, octinoxate | 2021 |
| Thailand (marine national parks) | Oxybenzone, octinoxate, 4-MBC, butylparaben | August 2021 |
| Maui (county, Hawaii) | Only mineral filters remain on sale | October 1, 2022 |
| Key West (Florida) | Oxybenzone, octinoxate | Never applied, overturned by a Florida law on June 30, 2020 |
These dates reflect official texts and announcements at the time. Check the rule on the official site of your destination before departure, as lists evolve.
And details vary from one text to another, between sale, distribution, and use in a protected area like in Thailand.
The case of Key West deserves attention. The city voted in early 2019 a ban on oxybenzone and octinoxate, planned for January 2021. On June 30, 2020, the Florida governor signed a law prohibiting cities in the state from banning sunscreens, in the name of skin cancer prevention. The local ban therefore never took effect. Many online lists still cite it as active (it has not been since 2020).
What to change before your next sea outing?
Start by reducing the amount of sunscreen that goes into the water. NOAA advises wearing UV-protective clothing, seeking shade between 10 a.m. and 2 p.m., and avoiding ingredients on its list. In our opinion, this is the most reliable measure, regardless of the filter, since it reduces the dose.
A UV-protective top covers the back and shoulders. These are the most exposed areas during a snorkel hike or a surface interval on the boat, and sunscreen then remains reserved for the face, neck, and hands.
Only then comes the question of the product, addressed in our article on coral-compatible sunscreens.
Beware of commercial claims. Neither NOAA nor Anses recognize “reef safe” as a guarantee. Rather, read the ingredient list. If you see one of the five filters flagged by Anses, the claim is worth little. For mineral products, the form matters, and in Europe the word [nano] must follow the concerned ingredient in the list.
However, sunscreen is only one of the actions that matter on a reef. Not touching or standing on the reef also counts, as detailed in our dossier on the real impact of diving on corals, to be complemented by our guidelines on ecotourism for diving without harming the environment.
The cost remains modest. A UV-protective top is a one-time purchase, slips on in seconds, and saves you some sunscreen each outing, while reading a label on the shelf takes two minutes.
FAQ
Is sunscreen the leading cause of coral death?
No. None of the reports cited here place it ahead of water warming. UV filters add to other pressures, with a more probable effect on shallow and heavily frequented sites.
Is a mineral sunscreen risk-free for reefs?
Not necessarily. NOAA cites zinc oxide and titanium dioxide in nanoparticle form among ingredients likely to harm marine life. The filter’s form and the rest of the formula matter.
Is my sunscreen with oxybenzone banned in Hawaii?
The state law, in effect since January 1, 2021, targets the sale and distribution of products containing oxybenzone or octinoxate. On Maui, only mineral filters have been on sale since October 1, 2022. Check before you go.
Does the European Union ban these filters to protect corals?
Anses’ July 2025 publication mentions no such ban. France announces preparing a restriction dossier on octocrylene with the European Chemicals Agency.
Sources
- Review of Fate, Exposure, and Effects of Sunscreens in Aquatic Environments and Implications for Sunscreen Usage and Human Health (National Academies of Sciences, Engineering, and Medicine, 2022)
- UV Filters, Metals, Pesticides… Coral Reefs Facing the Challenge of Chemical Pollution (Anses, 2025)
