Reef-Safe Sunscreen: The Facts and Myths
The term "reef-safe" is being prominently displayed on the labels of numerous new sunscreens, but what does it truly signify and should it prompt you to reconsider your sun protection strategy? The straightforward response to the latter question is: not unless you are visiting a destination that has implemented a ban on the sale of sunscreen products containing the chemicals oxybenzone and octinoxate. (Mexico, Hawaii, Aruba, Bonaire, the U.S. Virgin Islands, and Palau currently have such sunscreen bans in effect.) The reason for this is that these chemical UV filters potentially have a highly detrimental negative influence on the oceans where we swim, snorkel, and engage in scuba diving.
"Our estimate indicates that over 25,000 tons of sunscreen entered the water in tropical coastal areas in 2019 alone," remarks Craig Downs, Ph.D., the executive director of Haereticus Environmental Laboratory in Lynchburg, Virginia. "And that's a very cautious estimate." Downs led a 2015 study that discovered that all this chemical sunscreen was causing irreversible harm to reef ecosystems over time. The research demonstrated that high concentrations of oxybenzone and octinoxate in the water are poisonous to the algae within coral organisms and directly result in coral bleaching and mortality. While these two components are specifically identified, other chemical UV filters, such as octocrylene, could also be detrimental to marine life, Downs adds.
The reality is that much additional research is necessary. "Chemical sunscreen ingredients have been found to harm coral samples in laboratory studies," states Dr. Michelle Wong, an Australian Ph.D. scientist and educator based in Sydney. "However, the high concentration required to cause damage hasn't been recorded in the ocean, except in a few studies." (One of those studies is Downs' research in the U.S. Virgin Islands and Hawaii.) "Australia has not prohibited the sale of any chemical sunscreen based on reef concerns, even though our Great Barrier Reef is a national treasure," she says. Although sunscreen contamination is a valid worry, it might be relatively lower on the list of threats to coral reefs compared to climate change, rising sea temperatures, sewage, pollution, and overfishing. "If everyone stops using chemical sunscreen when entering the ocean, will that restore or halt the damage to reefs?" queries Ron Robinson, a cosmetic chemist in New York City and the founder/CEO of BeautyStat Cosmetics. "At present, we simply don't have sufficient scientific data to answer that question."
What Constitutes a "Reef-Safe" Sunscreen?
While there is no scientific definition for this term, it essentially refers to a mineral-based sunscreen containing active ingredients like zinc oxide and titanium dioxide and lacking the chemical UV filters oxybenzone and octinoxate. Nevertheless, this term is not regulated by the FDA, and no sunscreen formula has been clinically proven to be completely safe for coral reefs. There is also no standardized "reef-safe" certification to search for on packaging, although the Environmental Working Group (EWG) and Protect Land & Sea (part of the Haereticus Laboratory) have online listings of safe products that meet strict eco-friendly criteria. Ultimately, Wong views the term "reef-safe" as "largely a form of greenwashing," and Robinson considers it "a marketing strategy that influences consumers."
Are Some Mineral Sunscreens More Reef-Friendly Than Others?
It might depend on the size of those mineral particles. Micronized and nano-sized zinc particles are extremely small and are less likely to have the appearance and feel of white paste on your skin. (A nanometer is 1,000 times smaller than the thickness of a strand of hair.) "As of now, there is no scientific data indicating that mineral UV filters cause any harm to marine life because they do not absorb into or modify the organisms," Robinson explains. But to be truly eco-friendly and safe for corals, you could choose a "non-nano" mineral formula, although finding this information on a product label can be challenging. (Sometimes "non-nano" can be found in fine print next to the percentage of zinc.) "Non-nano mineral particles with a diameter of 100 nanometers or larger are relatively harmless, and some studies show that they behave like particulate sediments that sink to the ocean floor," Downs notes.
Two of our preferred non-nano choices are: Supergoop! Sunnyscreen 100% Mineral Lotion SPF 50 ($26) and Babo Botanicals Sheer Zinc Continuous Spray Sunscreen ($18.99), both of which blend smoothly into the skin.
The Final Verdict
You need to apply a broad-spectrum sunscreen with an SPF 30 or higher daily, and you will do so only if you are satisfied with how the formula appears and feels. "I don't want to tell people that they are limited to only mineral sunscreen options that are reef-safe because they might use that as an excuse and end up not wearing any sunscreen at all," says Dr. Orit Markowitz, a board-certified dermatologist in New York City. "You must consider the risk/benefit ratio - while it's crucial to do our small part to care for the environment, we also need to protect our skin by applying and reapplying sunscreen."
She also mentions that a mineral-based sunscreen has other advantages, such as functioning as a physical UV barrier the moment it is applied and being less irritating for sensitive skin. Markowitz suggests wearing a daily broad-spectrum sunscreen that you like, whether it is chemical or mineral. And if you are fortunate enough to be visiting a coral reef paradise this summer, utilize a mineral sunscreen (or, even simpler, UPF sun-protective clothing) on those beach days. "A sunscreen doesn't have to have the term 'reef-safe' on the label to be reef-friendly," Dr. Markowitz remarks. "As long as it is mineral-based, you can believe that you are being environmentally responsible."
