Woman swimming through a coral reef.

Last week, Hawaii became the first U.S. state to ban the sale of sunscreens containing two common chemicals, oxybenzone and octinoxate, which many researchers worldwide have deemed potentially harmful to aquatic life.

Hawaii’s Gov. David Ige signed the bill on July 3, and the law will go into effect in 2021.

“This bill is a small first step in Hawaii to really caring about our corals and our reefs in a way that really no one else anywhere in the world has done,” Ige said during a press conference.

While Hawaii’s state-level action is a first in the U.S., some retailers, such as REI, have agreed to stop carrying products that contain oxybenzone (though these policies have not yet gone into effect). And some sunscreen makers don’t use oxybenzone or octinoxate, and label their sunscreen “reef safe.”

But oxybenzone and octinoxate—which are two of the most commonly used UV blockers worldwide—aren’t the only two ingredients that may be damaging to marine life.

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In fact, says Craig A. Downs, Ph.D., executive director of the nonprofit Haereticus Environmental Laboratory, though oxybenzone and octinoxate are the most widely studied, there are several other chemicals used in sunscreens and other personal care products that research suggests might be an environmental threat. And even sunscreens labeled “reef safe” aren’t guaranteed to be harmless when they leach into underwater ecosystems.

Here’s how to keep your skin safe from the sun without putting the environment at risk. 

Sunscreen’s Environmental Toll

Climate change, pollution, and other environmental factors are slowly eroding the health of coral reefs around the world, which in turn can affect the health of the oceans.

But some of the ingredients in sunscreen may damage delicate coral reef systems as well. Up to 6,000 tons of sunscreen are estimated to wash into coral reefs around the globe each year. And as the National Parks Service cautions, rather than being evenly distributed, much of that sunscreen is concentrated at popular diving, swimming, and snorkeling sites—such as national parks. 

In a 2016 study by Downs and colleagues from the National Oceanic and Atmospheric Administration (NOAA) and other institutions, the authors found that baby coral exposed to oxybenzone and octinoxate exhibited signs of distress, including coral bleaching—a condition that leaves coral vulnerable to infection and prevents it from getting the nutrients it needs to survive—as well as DNA damage, and abnormalities in their growth and skeleton.

This bolstered the findings of a 2008 study performed by Italian scientists and published in the journal Environmental Health Perspectives, which found that commonly used sunscreen ingredients, including oxybenzone, caused coral bleaching in reefs across the globe, including in the Atlantic Ocean, Indian Ocean, and Pacific Ocean—even at low concentrations.

Other studies have also found the ingredients to be harmful to other marine organisms, too, such as fish, sea urchins, and shrimp.

Reef Safe?

If you think you’re in the clear as long as you buy a sunscreen labeled “reef safe,” think again, says Downs.

The federal government requires sunscreen claims to be “truthful and not misleading,” but the term “reef safe” doesn’t have an agreed-upon definition, and therefore isn’t strictly regulated by government. This means sunscreen manufacturers aren’t required to test and demonstrate that such products won’t harm aquatic life, says Downs. And even if they did and found a sunscreen that passed this test, says Downs, it might still be harmful if concentrations in the water got high enough. 

“Even if you have something relatively safe,” says Downs, “having 5,000 people getting into the water at a single beach, the oils from most sunscreen products can induce toxicity.”

Additionally, says Downs, there are several commonly used sunscreen ingredients—beyond the two banned by Hawaii and from many “reef safe” sunscreens—that might be harmful to marine life, such as octocrylene, homosalate, and octisalate.

A study published in 2014 in the journal Science of the Total Environment, for example, found that octocrylene might affect brain and liver development in zebrafish. That chemical, along with oxybenzone and octinoxate, has been found at detectable levels in various fish species worldwide.

Scientists are gathering evidence on some of these other potentially toxic ingredients, but it can take time to show proof of harm. Still, says Downs, “a lack of data doesn’t mean a chemical is safe."

What to Do Instead

All of this, of course, doesn’t mean you should abandon sunscreen, which provides essential protection against sunburns and skin cancer. And even Hawaii’s ban doesn’t apply to sunscreens prescribed by a doctor.

But there are some reef-friendly moves everyone can take.

If you plan to go into the water at the beach, the best way to protect both yourself and the environment may be to cover most of your body with UPF (ultraviolet protection factor) clothing—or even just a plain old T-shirt, which previous CR testing has found to offer excellent protection. You’ll still have to apply sunscreen to exposed skin, but you’ll need far less—up to half the amount—than you might if you were in a bathing suit.

“From an environmental perspective,” Downs says, that’s a “massive victory.”

Mineral sunscreens with “non-nanotized” zinc oxide or titanium dioxide (“non-nanotized” means the ingredients are 100 nanometers in diameter or more) appear to be safer for coral reefs than chemical ones, according to the National Park Service. But, Downs says, it’s near impossible for consumers to decipher which products meet this bill.

And unfortunately, in the past six years of sunscreen testing, none of the mineral products we’ve tested offer both top-notch UVA and UVB protection and meet their labeled SPF, says Susan Booth, the project leader for our sunscreen testing.

If you still want a mineral sunscreen, we suggest California Kids #Supersensitive Lotion SPF 30+ or Badger Active Unscented Cream SPF 30. Those both got “Good” scores in our most recent test, with California Kids offering better UVB protection, and Badger offering better UVA protection.

Another alternative is to use an oxybenzone-free chemical sunscreen. It won’t necessarily be reef safe, but at least you’ll avoid one of the chemicals with the most evidence of its potential for environmental damage.

The two such highest-scoring sunscreens in each category in our test were Well at Walgreens Moisturizing Lotion SPF 50 and Hawaiian Tropic Island Sport Ultra Light Spray SPF 30