When you spend time outside under strong sunlight, protecting your skin matters. You have two basic options: cover up or slather on sunscreen. Clothing is kinder to the planet than lotions—and worth considering first.

A long-sleeve shirt, a wide-brimmed hat, and a bit of shade protect you better than any lotion. You buy them once and reuse them for years. This is “reduce and reuse” in its most basic form. So before you think about liquid sunscreen, think about woven sunscreen.

The dual benefits of reusable sunscreen put this week’s step on two of the Sustainable Practice pathways at once. The Goods pathway is about buying less and reusing what you own—exactly what a long-sleeve shirt or hat does for sun protection. The Water pathway focuses on protecting the quality of the water we all share, where your liquid sunscreen ends up. Thoughtful choices for sun protection constitute a step along both the Goods and Water pathways to sustainability.

When you do need sunscreen

When you want to leave some bare skin exposed—your face, your ears, the backs of your hands—you will want liquid sunscreen. Sun protection lowers your risk of skin cancer, so don’t skip the lotion. The only question is which bottle you reach for.

Sunscreen lotions come in two families. Chemical sunscreens (also called “organic”) use molecules such as avobenzone, octocrylene, homosalate, octisalate, octinoxate, or oxybenzone in formulations that form a thin protective film on the surface of your skin. They absorb UV rays before that solar radiation can damage delicate structures in your body’s cells. On the one hand, this is a performance benefit: they feel less chalky. On the other hand, this protective film will wear off and can coat other organisms that don’t want those chemicals in their bodies. Mineral sunscreens (you’ll also see them called “inorganic” or “physical” sunscreens) contain small particles of zinc oxide or titanium dioxide that sit on the surface of your skin and absorb or reflect the sunlight away, the way tiny mirrors would. Both kinds of lotions protect you, but chemical sunscreens cause more harm to ecosystems when they enter water.

Why chemical sunscreens are a water problem

The sunscreen you put on doesn’t stay on forever. Some rinses off if you swim, but much of the rest comes off in your evening shower and a bit more when your towels go through the wash. As the top layers of your skin slough off (your epidermis naturally renews completely every 28 to 42 days), almost all the sunscreen you put on your body will eventually end up in the environment. At a treatment plant, some oxybenzone and octinoxate passes through—conventional treatment was never designed to catch all of it—and ends up in rivers, lakes, and the sea.

What they do when they get there raises serious concerns. Research led by NOAA scientists found oxybenzone toxic to young coral, bleaching it and deforming its growth at concentrations as low as a single drop in several Olympic-size swimming pools. Those findings are why Hawaii banned the sale of sunscreens containing oxybenzone and octinoxate, with Key West, the U.S. Virgin Islands, and the island nation of Palau close behind.

The same compounds now turn up in freshwater far from any beach, where several act as endocrine disruptors in fish and other aquatic life. A coral reef is a vivid example, but other aquatic ecosystems are just as affected—the National Park Service estimates that 4,000 to 6,000 tons of sunscreen wash off swimmers worldwide every year. More enters waterways through household drains from showers and baths.

Are mineral sunscreens actually safe, or just a different problem?

It’s a fair question whether any type of sunscreen lotion is truly environmentally friendly, since none of them are perfectly inert. The honest answer is that compared to oxybenzone and octinoxate, zinc oxide and titanium dioxide are likely safer for living systems. Because they are designed to sit on the surface of your skin rather than dissolve into a water-soluble film, far less of these products are in a form that aquatic life readily absorbs. The fact that they are intended to stay on top of your skin rather than be absorbed into your body is at the heart of why mineral sunscreens are the better choice.

The one wrinkle worth knowing is particle size. To keep mineral sunscreens from leaving a white cast, some are made with “nano” particles, ground so small that they rub in clear. Laboratory studies have found that these tiniest particles can be taken up by small marine organisms and, in sunlight, generate cell-stressing free radicals that have harmed corals, microalgae, and water fleas in testing. Larger “non-nano” particles don’t show the same deleterious effects. That’s why the National Park Service points to non-nano zinc oxide or titanium dioxide as the safest option for reefs. So mineral is the better family, and the “non-nano” label makes it even better. Both nano and non-nano protect your skin equally well; the difference is the white cast, not the safety.

In addition to the active ingredients that block solar radiation, sunscreen formulas include water, oils, preservatives, and fragrance—and some of that reaches the water too. You can’t reasonably audit every ingredient in a bottle (unless you use artificial intelligence to help), but the active-ingredient panel is the regulated part and the biggest lever, so that’s where to look.

A quick word on sprays

Sprays raise two issues, no matter what active ingredient they use. A good share of the mist never lands on you—it drifts onto sand, soil, and water, which is why many tour boats ban it outright. Some aerosol propellants are flammable, and all are easy to inhale, with several spray products recalled in recent years over benzene contamination. Mineral sprays do exist and tend to be based on zinc oxide rather than titanium dioxide. The latter has been flagged as a possible carcinogen when it’s inhaled as a fine mist. Marine scientists note a spray isn’t inherently worse for a reef than a lotion; what matters most is still mineral versus chemical. But a rub-on mineral lotion or stick applies more product to your skin and releases less into the air around you.

Your one step this week

Your sun protection strategy should start with clothes. Reach for a shirt, a hat, and shade first, and you’ll need less sunscreen lotion. Then, before buying a bottle, read the small boxed list marked Active Ingredients—the regulated truth, not the marketing on the front:

  • Zinc oxide or titanium dioxide, ideally labeled non-nano: this is your best choice.

  • Oxybenzone, octinoxate, octocrylene, or homosalate: set it back on the shelf.

Don’t trust the words “reef-safe” or “reef-friendly”—neither is regulated, so any product can claim them. In May 2025, the maker of Sun Bum paid a $300,000 settlement to the Santa Clara County District Attorney over “reef-friendly” labels on sunscreens that contained reef-harming chemicals. The front of the bottle is an advertisement. The ingredient list is the truth.

Now that you know environmentally friendly ways to stay safe from the sun, you’re ready to enjoy this and every summer to come!

To see how small choices like your sunscreens connect to the whole pathway to clean water and a sustainable future for all, get the Sustainable Practices Handbook and visit www.suspra.com for more resources. And here are two more One Step pieces that make good next reads: everyday ocean-friendly swaps for your home, and last year’s World Oceans Day issue on cutting household microplastics before they reach the sea.

References and Resources

Related One Step Articles

Join Sustainable Practice

Expand your positive impact on Earth by becoming a sustainable practitioner today!
www.sustainablepractice.life

Sustainable Practice empowers you to protect our planet in practical ways. Share this article with someone heading outside this weekend—to the beach or just the backyard—to help keep our water a little cleaner and our ecosystems a little healthier.