Climate change, pollution and ocean-dependent industries are slowly damaging coral reefs around the world. There's something else -- something seemingly innocent -- that could be contributing to the loss of these colorful underwater colonies: your sunscreen.
Some chemicals in sunscreen have been linked to damage of coral reefs, although there's more to the evidence than what initially meets the eye.
I don't want to send mixed signals, so I'll say this flat-out before diving in: You should wear sunscreen any time you are in the sun, especially if your skin is unprotected by clothes or shade. The most important thing is to protect yourself from skin cancer by avoiding UV damage, whether your method be sunscreen, clothes or umbrellas.
That said, here you can learn from board-certified dermatologists and marine biologists about the pros and cons of reef-safe sunscreens, and how choosing a reef-safe sunscreen can benefit both your health and the environment's health.
Watch this: I got my face professionally scanned for wrinkles and UV spots
What is reef-safe sunscreen?
A reef-safe sunscreen is a sunscreen free of chemical ingredients and small particles known to damage and potentially kill coral reefs in the oceans. Those ingredients are, to date, oxybenzone, octinoxate and octocrylene.
There's more to consider than just the ingredients in your sunscreen, though, which is where things get a bit sticky: To be truly reef-safe, the particles in sunscreen must be "non-nano." If the particle size is below 100 nanometers, coral reefs can absorb the particles from sunscreen regardless of the ingredients.
In fact, the primary reason mineral sunscreens are more eco-friendly is due to them being non-nanotized, says Casper Ohm, a marine biologist senior research writer at Water Pollution. This means that reef-safe sunscreens "are made with bigger 'natural-sized' particles that are healthier for marine life and the local ecosystem," Ohm tells CNET.
To recap, here's what makes a truly reef-safe sunscreen:
No oxybenzone, octinoxate or octocrylene
Particle size above 100 nanometers
Look for a "reef-safe" label when shopping, but double check the ingredients list. The phrases "reef-safe" or "reef-friendly" are not regulated by the FDA, so the simplest way to choose a non-nanotized sunscreen is to use a mineral-based cream or lotion instead of a mist or spray. Aerosolized sunscreen is almost guaranteed to contain particles smaller than 100 nanometers in size that can be ingested by coral reefs.
Here are a few popular reef-safe sunscreens to look for when shopping:
Scientists have found that some chemicals in sunscreen contribute to coral bleaching, a process by which coral reefs expel the colorful algae that lives in the corals' tissues. Bleaching doesn't kill coral, but it does leave the coral at risk for infections and mortality.
There's also come concern that one specific ingredient, octocrylene, can directly contribute to the death of coral reefs.
To help you better understand the impacts of chemical sunscreen ingredients on coral reefs, here are the findings and limitations of some of the most widely cited studies on sunscreens and coral reef health:
In 2008, scientists concluded that sunscreens cause viral infections in corals, which resulted in rapid bleaching, leaving them susceptible to death, especially in corals subjected to higher water temperatures. However, the study involved direct application of sunscreens to corals and higher concentrations of sunscreen than found in natural settings, which doesn't represent real-life scenarios.
A 2015 study found that oxybenzone directly contributed to bleaching of coral in both light and darkness, and that oxybenzone caused the planula (an important component of coral reproduction) to harden. This study was conducted in laboratory settings.
Another 2015 study replicated the findings of the above study, but this time with benzophenone-2 (another chemical in the same class as oxybenzone). This study was conducted in laboratory settings, which may or may not correlate to real-life settings. It also has several corrections.
Yet another study in 2017 speaks out against oxybenzone as a harmful compound to both humans and coral reefs, but again, uses laboratory data that may or may not reflect what's really happening to the coral reefs.
The island nation of Palau released a report in 2017 (PDF) that says scientists detected harmful levels of 10 chemicals in Jellyfish Lake, a popular tourist attraction for swimming and water sports. Those chemicals have since been banned for sale and use in Palau.
It was conducted in laboratory settings, rather than in real environments.
It focused on individual chemicals, rather than sunscreens as a whole.
The duration of studies has been relatively short (a few hours up to a few days), with more information needed about the long-term impacts.
In sum, more research is needed.
However, "more research is needed" isn't a good reason to totally disregard the health of our coral reefs. Damage to the reefs is happening, whether it's due largely to sunscreens or not, and consumers have an opportunity to protect the reefs while also protecting themselves with adequate sunscreen.
"The damage is bad but it could be much worse," Ohm says, "and if we continue dumping sunscreen into the ocean it could threaten coral populations worldwide. Coral reefs are already at risk due to rising water temperatures, and getting covered with a cocktail of toxins certainly doesn't help." To be clear, more research is needed to determine how toxic sunscreens and the ingredients in them.
Ohm says he thinks there's a chance to mitigate the damage by raising awareness about the potential harms of sunscreen and the risks posed to the environment.
If enough people were aware of the damage caused by sunscreen, he says, many could be swayed into buying eco-friendly sunscreen that might cost a little bit more but is perhaps less likely to damage the environment.
"Corals can regrow and recover over time, and if we start changing our habits soon then we still have a chance of reversing the damage we've done so far," Ohm says hopefully.
Where are chemical sunscreens banned?
Before you head out on a tropical vacation this summer (following safe travel protocols as we muster through the coronavirus pandemic, of course), check to see if your sunny destination has banned sunscreens with certain chemicals.
Hawaii, for example, prohibits the sale of sunscreen with oxybenzone and octinoxate. The law was passed in May 2018 by Hawaii legislators and signed by Gov. David Ige. While the new law doesn't officially go into effect until Jan. 1, 2021, many retailers, resorts and parks are already encouraging visitors to choose reef-safe sunscreens, such as Hanauma Bay State Park.
Other places where certain chemical sunscreens are banned include:
In Mexico, lawmakers haven't enacted enforceable legal bans of sunscreen, but some tourist destinations, including the Riviera Maya, encourage visitors to use biodegradable reef-safe sunscreens in place of chemical sunscreens.
The city legislature of Key West, Florida, tried to enact a sunscreen ban, but Florida lawmakers preempted the bill, saying that cities cannot enforce their own sunscreen bans due to concerns about rising skin cancer rates. The city of Key West still encourages locals and tourists to use eco-friendly sunscreens.
It may be unlikely that someone will actually check your bag for banned sunscreen (though it's a possibility), but you can still take this as an opportunity to do some good for the environment by making an easy switch: Look for sunscreens free of oxybenzone and octinoxate, as well as octocrylene.
If you can't find any locally before you depart, just stock up when you arrive at your destination -- if the ingredients are already prohibited there by law, your only options will be reef-safe sunscreen anyway.
Chemical sunscreen and human health
When it comes to your health, something is always better than nothing, says Dr. Christina Lee Chung, a board-certified dermatologist based in Pennsylvania.
"I am partial to mineral sunscreens because they function as physical barriers to UV rays which simply reflect the UV energy away from one's skin," she says. "In contrast, chemical filters absorb a defined spectrum of UV rays and dissipate them as heat through a chemical reaction."
Although Chung generally recommends mineral sunscreens for health reasons -- especially in her clinical practice, where she treats immunocompromised patients -- she recognizes that not everyone can or will buy mineral sunscreen.
Another consideration is cosmetic concern, Chung says. "Some mineral sunscreens have a tendency to leave a white cast when applied," she says, and "this can make it cosmetically difficult for persons of color to use."
"I am encouraged that the major sunscreen companies have recognized this challenge and are producing tinted mineral sunscreens and sunscreens that blend across skin tones, but darkly pigmented individuals may still find it difficult to identify a mineral sunscreen that works for them," Chung continues.
For that reason, a chemical sunscreen is sometimes the better choice -- because if you don't like the way it makes you look, there's a good chance you won't wear it, which leaves your skin at risk for sun damage and, at worst, skin cancer.
A delicate balancing act
Dr. Adam Mamelak, an Austin-based dermatologist, empathizes with both sides of the debate.
"Coral reefs are some of the most beautiful yet delicate ecosystems in the world, and are already in danger from commercial pollutants, tourism and fishing industries," Dr. Mamelak tells CNET.
"In recent years," he continues, "scientists have discovered that the UV blockers in sunscreen can bleach coral, damage algae growth and could potentially be toxic to marine life."
This isn't caused solely by divers and swimmers wearing sunscreen, Dr. Mamalek emphasizes, as polluted water from showers and pools can run into local waterways and into the oceans. For areas that rely on coral reef tourism like Hawaii, Florida, Palau and Australia, the ban on certain ingredients such as oxybenzone and octinoxate are an attempt to protect the ocean and its related industries.
However, "Sunscreen has undeniable health benefits for the individual," Dr. Mamalek says, citing statistics from the Skin Cancer Foundation which say that regular sunscreen use can reduce a person's chances of developing skin cancer by up to 50%.
Plus, Dr. Mamelek says, everyone should consider the other causes of coral bleaching and coral death, of which there are many, the primary culprit being changes in ocean temperature.
Although making the switch to reef-safe sunscreen is a good step, true environmental change comes about with sustained efforts among a variety of aspects -- such as reducing your overall day-to-day waste, water usage and energy usage -- rather than knee-jerk reactions that pertain only to one very specific element of environmental harm.
Like many things, the great sunscreen debate requires a careful weighing of two sides. Your health is of the utmost importance, so you should choose sunscreens that are safe for you -- and sunscreens that you don't hate, so you'll actually wear them.
The health of our environment is also important, and Earth deserves consideration from consumers. If you have the means to choose mineral, reef-safe sunscreens (and you'll actually wear them and reapply as directed), it's a good choice to make for your own health and the health of the environment.
The information contained in this article is for educational and informational purposes only and is not intended as health or medical advice. Always consult a physician or other qualified health provider regarding any questions you may have about a medical condition or health objectives.