Your Sunscreen Is Killing the Reef and the Label Says It Isn't

The term "reef safe" has no legal definition. The chemicals in most sunscreen cause coral to poison itself. Six governments have banned the stuff. And the tube in your bag probably still contains it.

Pemulis Water & Power • February 2026

In 2015, a forensic ecotoxicologist named Craig Downs published a paper in the journal Archives of Environmental Contamination and Toxicology that should have changed the sunscreen industry overnight. Downs ran the Haereticus Environmental Laboratory, a nonprofit in Virginia, and he had spent a decade collecting water samples from reef sites around the world — the Great Lakes, Alpine lakes in Switzerland and Germany, bays in Hawaii, the U.S. Virgin Islands — measuring concentrations of a chemical called oxybenzone, which is the active UV-filtering ingredient in roughly eighty percent of sunscreens sold worldwide. What he found in the U.S. Virgin Islands was oxybenzone at concentrations ranging from 75 micrograms per liter to 1.4 milligrams per liter. In Hawaii, levels ranged from 0.8 to 19.2 micrograms per liter. These numbers meant nothing to the public. They meant everything to the coral.

Downs's lab work showed that juvenile coral — the planulae, the free-swimming larvae that settle on the reef and grow into new colonies — began to deform at concentrations of 6.5 micrograms per liter. At 139 micrograms per liter, half of them died within twenty-four hours. In the Virgin Islands, the water already contained ten times the lethal dose. The mechanism was brutal and specific: coral tissue absorbs oxybenzone and metabolizes it through a reaction called glycosylation, producing a new compound — oxybenzone glucoside — that still absorbs ultraviolet light but can no longer release the energy as heat. Instead, it generates reactive oxygen species, free radicals that shred cells from the inside. In sunlight, the very thing oxybenzone is supposed to protect you from, it becomes a poison inside the coral that absorbs it. The coral bleaches, the tissue dies, and the reef loses another colony.

A team at Stanford confirmed the mechanism in 2022 and added a detail that made it worse: the symbiotic algae that live inside coral tissue — zooxanthellae, the organisms that give coral its color and produce most of its energy through photosynthesis — normally help sequester the toxic compounds that oxybenzone produces. But when coral is stressed by warming water, it expels those algae. That process is bleaching, and it's already happening at scale across every tropical reef system on earth because of rising ocean temperatures. A bleached coral is a coral without its chemical defense system, and oxybenzone hits hardest precisely when the reef is already at its most vulnerable. The two crises — warming and chemical contamination — don't just coexist. They compound each other.

The Numbers

Between four thousand and six thousand metric tons of sunscreen wash off the bodies of swimmers into ocean reef ecosystems every year. In Mexico's Quintana Roo region alone — Cancún, Cozumel, the stretch of Caribbean coastline that hosts the world's second-largest barrier reef — more than three hundred metric tons entered the water in a single year. This is not a diffuse, hard-to-quantify environmental concern. This is a measurable chemical load being delivered directly to the reef, every day, by tourists who are doing exactly what the tourism industry told them to do: put on sunscreen and get in the water.

The Caribbean has lost somewhere between fifty and eighty percent of its coral cover in recent decades. Fourteen percent of the world's reefs have disappeared since 2009. The sunscreen load is not the primary driver — that's climate change, full stop — but it is a compounding stressor that hits the hardest in exactly the places where reefs interact most with people, which are also the places where reef tourism generates the revenue that's supposed to fund reef conservation. The economics are circular and grim: people visit the reef, the reef dies a little from the visit, the dying reef attracts fewer visitors, the conservation funding shrinks, and the reef dies a little more.

Juvenile coral began to deform at 6.5 micrograms per liter. In the U.S. Virgin Islands, the water contained ten times the lethal dose.

The Bans

Hawaii was the first state to act, passing Act 104 in 2018, effective January 1, 2021, banning the sale of sunscreens containing oxybenzone and octinoxate — the two chemicals most directly implicated in Downs's research — without a prescription. In 2023, Hawaii expanded the ban to include avobenzone and octocrylene. The U.S. Virgin Islands had actually moved first, passing a unanimous ban in June 2019 on all three of what they called the "Toxic Three Os" — oxybenzone, octocrylene, and octinoxate — with an effective date of March 2020, making it the first U.S. jurisdiction to implement a full prohibition. Key West followed, banning oxybenzone and octinoxate effective January 2021. Bonaire, in the Dutch Caribbean, implemented the same ban on the same date.

Palau went the farthest. In 2018, the Pacific island nation banned ten sunscreen chemicals — not just the worst two, but the full range of suspected reef toxicants — and began enforcing the ban at the point of entry, confiscating non-compliant sunscreen from tourists arriving at the airport. Palau treats chemical sunscreen the way some countries treat controlled substances: you can't bring it in, you can't buy it, and if you're caught with it the government takes it.

The industry pushed back. The Hawaii Medical Association opposed the ban. So did the Consumer Healthcare Products Association, the American Chemistry Council, and the Hawaii Food and Industry Association. Their argument was straightforward and technically accurate: Hawaii was reducing consumer access to FDA-approved products. What the argument omitted was that FDA approval considers human safety, not reef safety, and that the FDA has no testing protocol, no standard, and no regulatory framework for evaluating what a product does to marine ecosystems after it washes off the person it was applied to.

The Label Problem

Here is the thing about "reef safe" sunscreen: the term means nothing. It has no legal definition. The FDA does not recognize it, does not regulate it, and has established no criteria for its use. Any sunscreen manufacturer in America can print "reef safe" or "reef friendly" or "ocean safe" on a tube of product that contains any chemical they want, and there is no federal agency that will stop them, no testing requirement they must satisfy, and no penalty they will face unless a state attorney general decides to sue ��� which, to the credit of Santa Clara County, California, is exactly what happened.

Sun Bum, the beach-lifestyle sunscreen brand recognizable by its yellow monkey logo, settled a false advertising case for three hundred thousand dollars after marketing products containing oxybenzone and octinoxate as "reef friendly." Supergoop, another popular brand, settled a similar case for three hundred and fifty thousand dollars. These were not fringe companies making obscure claims on products nobody bought. These were mainstream brands, sold at Target and Sephora and in every surf shop in California, making environmental claims that were, according to the state, materially false. The settlements were small enough to function as a cost of doing business. The labeling practices, industry-wide, have barely changed.

Any sunscreen manufacturer in America can print "reef safe" on a tube containing any chemical they want, and no federal agency will stop them.

What "Mineral" Actually Means

The alternative to chemical UV filters is mineral UV filters — specifically, zinc oxide and titanium dioxide — which sit on top of the skin and physically reflect ultraviolet light rather than absorbing it and converting it through a chemical reaction. Mineral sunscreens do not penetrate the skin in the same way chemical formulations do, they do not produce the reactive oxygen species that damage coral tissue, and they are the only class of UV protection that every jurisdiction with a sunscreen ban has explicitly permitted. This does not mean all mineral sunscreens are ecologically benign — nano-particle formulations of zinc oxide raise their own questions about marine toxicity — but the non-nano mineral category represents the closest thing available to sunscreen that does what it claims without quietly destroying the ecosystem it's used in.

Avasol makes mineral sunscreen. Non-nano zinc oxide and titanium dioxide, no oxybenzone, no octinoxate, no avobenzone, no octocrylene. The formula carries a USDA 100% Biobased certification, an eighty-minute water resistance rating, and broad-spectrum SPF protection at 30 and 50. It was developed by a surfer, for surfers, in a market that has spent decades telling surfers to slather on chemicals that are measurably killing the reefs they surf. That is the sales pitch, and it is also just the situation as it exists: the sunscreen industry sold a product that damages the ocean to people who love the ocean, and the people who love the ocean are now the ones who have to sort out the alternative.

We carry Avasol at Pemulis Water & Power — the Environmental Defense Cream SPF 30, the Barrier Cream, and the Surfer's Barrier Stick SPF 50. It is not the only mineral sunscreen on the market, and we are not going to pretend that buying a twenty-dollar tube of anything constitutes environmental activism. But it is sunscreen that does not contain the chemicals that six governments have now deemed harmful enough to ban, and if you are going to put something on your skin before you paddle out, that seems like a reasonable minimum standard.