The downside of sunscreen: How sunscreen is harming coral reefs and other marine life

Screen Shot 2018-04-23 at 19.18.39Sunbathing in Vondelpark (Elhawk, 2010)

Finally, the sun was out in Amsterdam last weekend, reaching temperatures of around 27 degrees. In a summer dress, shorts, or bikini, on the terrace, in the park, or at the beach, the sun was enjoyed through all kinds of different activities. The spring sun is more treacherous as you might think, so I hope, whatever you were doing, you protected yourself with sunscreen. Because we all know right, sunbathing unprotected is highly increasing your chances of skin cancer. Unfortunately, although sunscreen is good for you, it might not be as good for the environment. Last week, I came across an article saying that sunscreen could be damaging the environment (Mcmahon, 2018). The article states that sunscreen in the water is leading to coral bleaching and harming marine life. Not again a human-induced pressure on the environment! So let’s figure out why sunscreen is harming the environment, whether the effect is significant and what we can do about it.

The cause of the problem
The main ingredient in sunscreen that is protecting us against ultraviolet radiation is called oxybenzone (Bronstein, 2016). This chemical is also used in other personal-care products, such as perfumes, shampoo, facial creams, and mascara, as well as in household products such as dishwasher soap and hand soap. Exactly this ingredient is becoming of increased concern for the environment. When we go for a swim in the sea, part of our sunscreen is released into the water and subsequently harms the environment. Tashiro and Kameda (2013) showed that our sunscreen can travel distances of approximately 600 m through the water from its point of emission. Bronstein et al. (2016) found that approximately 6000 till 14000 tons of sunscreen annually ends up in areas where coral reef is present. The U.S. Environmental Protection Agency also discovered the presence of oxybenzone in our residential and municipal waste water effluent, which later ends up in our natural waters. So not only by swimming, but also through for example showering or bathing after walking in the city for a day, you release this toxin into the environment.

What does it do?
Oxybenzone is toxic on molecular levels all the way up to multi-organ system levels. Oxybenzones are mutagens known to induce damage to DNA. Their effect is enhanced in the presence of sunlight and varies amongst different marine species and coral reefs. Coral larvae and juvenile coral are most vulnerable to the impact. The chemical often interferes with reproduction and growth and aggravates coral bleaching (Bronstein et al., 2016). Bronstein et al. (2016) investigated various beaches over the world, under which two bays at St. John Island. Trunk Bay, which has many recreational swimmers and therefore detectable levels of oxybenzone, was compared with Caneel Bay, which is a quiet bay. According to their expectations, Caneel Bay had a healthy coral community with abundant coral larvae and juvenile coral, while almost no regeneration of coral reefs had taken place over an observation period of 5 years at Trunk Bay. The same trend was observed in areas all over the world, such as Eilat, Aqaba, Hawaii, and Cancun, and is thus of serious concern. In combination with various other stress factors, such as ocean acidification and microplastics, sunscreen emissions highly threaten coral reef resilience. Coral bleaching as a consequence of ocean acidification has received significant attention over the past few years. The effects of sunscreen lotion on coral reefs are far less published. As sunscreen usage is much easier to alter than ocean acidification, this problem definitely needs more attention.

The value of coral reef
Why do we worry so much about coral bleaching? Coral reefs deliver a positive contribution to tourism, fisheries, coastal protection, biodiversity and carbon sequestration. The National Oceanic and Atmospheric Administration has put a monetary value on coral reefs and estimated the total value of all coral reef globally per year to be 29.8 billion. Tourism and recreation accounted for the greatest share, namely 9.6 billion dollars, coastal protection was found to be worth 9 billion dollars, fisheries 5.7 billion dollars and biodiversity 5.5 billion dollars (Conservation International, 2008).

Coral reefs are an important tourist attraction for islands like Hawaii, the Caribbean and the Philippines. Therefore, initiatives are popping up to protect coral reefs against sunscreen. The Hawaiian senator, for instance, proposed a bill to ban the sales of all oxybenzone containing sunblock at the island, but this bill has yet to be passed (Vesper, 2017). Brands such a L’Oréal, have been denying the research and also lobbyist groups such as the DC-based Consumer Healthcare Products Association have been fighting against the ban. They argued that there is a lack of scientific evidence (Vesper, 2017). There are also some bottom-up initiatives that try to stimulate use of reef-safe sun protection. The Aqua-Aston Hospitality, a large hotel and resorts group in Hawaii, distributes free and harmless sunblock. Additionally, they have introduced free sunblock stations on its property. These initiative have stimulated others to take action as well, such as the Waikiki Aquarium, who also installed sunscreen stations and are educating people in various hotels to increase public awareness about the issue (Gonzalez, 2018).

I believe its the collective responsibility of all humans to protect coral reefs and put pressure on legislators and manufacturers to ban the use of oxybenzone in sunblock. We should take these small bottom-up initiative as example and, therefore, I hope to have encouraged you all to check the ingredients next time you buy sunscreen. Rather than denying the research, like L’Oréal, a few brands took a different approach and have been producing sunscreen lotions that are coral-reef friendly by using alternatives for oxybenzone. But, be aware, scientists found that some of these seemingly reef-safe lotions still contain oxybenzone. Thus, similarly as we have to watch out for many food products that print superficial claims on their packaging, such as ‘natural’ or ‘sustainable’, also sunscreen is prone to green washing!

Bronstein, O., Cadenas, K., Ciner, F.R., Downs, C.A., Fauth, J., Jeger, R., ….. Woodley, C.M.
(2016). Toxicopathological Effects of the Sunscreen UV Filter,Oxybenzone (Benzophenone-3), on Coral Planulae and Cultured Primary Cells and Its Environmental Contamination in Hawaii and the U.S. Virgin Islands. Arch Environ Contam Toxicol, 70,265-288. Doi: 10.1007/s00244-015-0227-7

Conservation International. 2008. Economic Values of Coral Reefs, Mangroves, and
Seagrasses. A Global Compilation. Center for Applied Biodiversity Science, Conservation International, Arlington, VA, USA.

Gonzalez, M. (2018, April 3). Hotel gives out environmental friendly sunscreen to protect Hawaii’s coral reefs. KITV4. Retrieved from: sunscreen-to-protect-hawaiis-coral-reefs

Mcmahon, S. (2018, April 19). What Your Sunscreen Is Doing to the Environment. Smarter
Travel. Retrieved from:

Tashiro, Y., Kameda, Y. (2013). Concentration of organic sun-blocking agents in seawater of beaches and coral reefs of Okinawa Island, Japan. Marine Pollution Bull, 77, 333–340

Vesper, I. (2017, February 3). Hawaii seeks to ban ‘reef-unfriendly’ sunscreen. Nature. Retrieved from:

Elhawk. (Photographer) (2010, June 24). Sunbathing in Vondelpark [digital image]. Retrieved from:


4 thoughts on “The downside of sunscreen: How sunscreen is harming coral reefs and other marine life

  1. Very interesting blogpost, I hadn’t heard about the dangers of sunscreen before! You mention ocean acidification and that the damage from sunscreen can be addressed more easily. Do you know the amount of damage of sunscreen relatively to the damage of ocean acidification, or is there no data on this yet? Or is the damage of acidification more long term and will accumulate over time, because of the wide scope of acidification where the problem of the sunscreen is more locally and could be addressed more locally as well? Not saying that it is not important to change these problems, but I do not think that if the sunscreen damage is relatively small that you can really compare the timescale/effort level of solving the sunscreen problem to solving the ocean acidification problem. I think that it should be seen more as two problems that both destroy coral reefs and should both be solved as soon as possible.

    Do you think that a ban on oxybenzone in products would be effective and achievable (while also creating oxybenzone free products)? Or do you think that it could turn out to be like the move from CFCs (resulting in the hole in ozone layer) to the use of HCFCs/HFCs (which still act as GHGs but less harmful)? Meaning that oxybenzone free products will lead to other types of sunscreen that may include other harmful substances?


  2. Thanks for your blog post, it was interesting to read. I have always noticed some of my sunscreen coming of while swimming in the water, but have never thought about it being harmful for the environment.
    Im interested in the why they havent taken out this ingredient yet, is there no suitable easy ingredient to replace it or are alternatives still too expensive? You mention the fact that hotels give out free sunscreen with a different substance in it, has this been proven to work?
    Furthermore I am interested in whether this is a big factor in damaging the coral reefs, or same as Emma points out, that this might not be a leading factor ind damaging our reefs?


  3. Hi Emma,

    Thank you for your comment, I will clarify a little what I mean to say with “As sunscreen usage is much easier to alter than ocean acidification”. Ocean acidification is caused by the high amount of CO2 that is absorbed by the oceans, which has multiple causes. Sunscreen usage is a single source that is very clear and well defined and therefore can be easily targeted. Damage of sunscreen is indeed more locally, but therefore not less important. The impact cannot be compared with the effect of acidification on coral reefs worldwide. However, sunscreen usage targeting could be a relatively easy way to at least reduce part of the stress that coral reefs endure.

    As this topic is relatively new, there should be more research into the effects of the substitutes, but what I have read so far, the substitute should not be harmful to coral reefs. I think a ban is therefore very realistic and achievable.


  4. Hi Menno, good question why most companies are unwilling to change. I have done some research, but I cannot find the reason. There is definitely a good substitute that has proven to work, but I guess it might be a little more costly? Acidification affects coral reefs on large scale and this problem will not be solved by targeting sunscreen. The impact of sunscreen affects coral reefs locally, but that does not mean it is less harmful. Targeting sunscreen use will save local reefs and will be a first step in preserving them. Acidification remains as problem that needs to be targeted because if that continues all coral reefs will die, even when we ban sunscreen.


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