Biodegradable Sunscreens & Bodycare Must Be Tested to Determine Safety

Made with Natural Ingredients. Biodegradable. Reef safe. Chemical free. Green.
These are all very loosely regulated claims with respect to sunscreen safety. We have learned that you can not simply trust that what is on the front of a label is truthful. Certain ingredients in sunscreens are toxic to corals and reef fish, but are still in products that are labeled as reef safe and biodegradable. In addition, NOAA estimates that 4,000 to 6,000 tons of sunscreen washes off our bodies and into our coral reefs every year.
We have also discovered that just because a product is safe for people does not mean it’s safe in an aquatic ecosystem. Modern science has given us many lab tests to determine the safety of cosmetics, but currently, the only way to determine if products are harmful to fish, coral and other aquatic life is to test them on real subjects.  We put Stream2Sea products through numerous studies to prove our safety, and believe that our products are the safest on the market for all your water, reef and outdoor activities.


Fact: Certain ingredients in biodegradable sunscreens are toxic to corals and reef fish, but are still in products that are labeled reef safe.

Stream2Sea Product Test Results

Protect Land + Sea Certification

Haereticus Environmental Lab created the Protect Land + Sea (PL+S) certification because selecting a reef-safe sunscreen is more challenging than it should be. HEL is a non-profit, scientific organization whose mission is to conserve wildlife and ecosystems. If a product wears the Protect Land + Sea Certification Seal, consumers, park rangers, and businesses can rest assured that a product does not contain ingredients that may be harmful environmental pollutants.

Biodegradable Does Not Mean Non-Toxic

It is important to know that just because a product is biodegradable for example, a biodegradable sunscreen, does not mean that it is non-toxic. There are several tests to measure a product’s biodegradability, and most are designed to analyze the product’s ability to breakdown in wastewater treatment facilities. To be considered ‘readily biodegradable’, the product must break down into its natural state from 60-80% in 28 days.   ‘Inherently biodegradable’ means it will break down from as low as 20% to 60% in 28 days. So if a product says it is ‘biodegradable’, that is a good first step to knowing that the company is looking at its product’s environmental breakdown.  However, it’s important to understand that you cannot measure a product’s safety just by looking at its ability to biodegrade. That said, it was important for us to know that our products would, in fact, biodegrade in their natural environments, so we tested in both fresh water, as well as salt water.

Aquatic Toxicity and Safety

We began by testing on C. Elegans, simple nematodes, which are ideal for rapid, predictive screening on inflammatory ingredients. We then moved on to freshwater and saltwater fish species, looking at the impact on the fish’s eating behavior, swimming behavior and, of course, mortality rates. Our studies were prepared and conducted by the EcoTox team at Eckerd College. The test subjects were fed at the same time every day and the same amount of food for 96 hours. The fish were exposed to the highest concentration of product that any marine animal or plant would ever naturally come into contact with. For each test, we added a competitor’s product to one group of subjects, the second group was exposed to the same concentration of Stream2Sea’s biodegradable sunscreens and product, and finally, the control group was not exposed to any foreign products. During every observation period, mortality rate, feeding behavior and swimming behavior was recorded. These experiments were done for each of our products before determining their safety. We were pleased to note that our sunscreen did not generate any mortality.

Swimming Behavior in Fishes

What these results show is that swimming behavior with Stream2Sea biodegradable mineral sunscreen is relatively unaffected, whereas the competitor sunscreen most definitely altered the fish’s swimming behavior. Baitfish may be sluggish in the water and not as responsive to their environment. In the wild, sluggish fish would be more vulnerable to predators, and less likely to find or compete for food.

Feeding Behavior

What these results show is that feeding behavior with Stream2Sea sunscreen is relatively unaffected, whereas the competitor sunscreen most definitely altered the fish’s desire to feed.

Coral Larvae Settlement Tests

Stream2Sea biodegradable mineral sunscreens (SPF 20 and 30) did NOT significantly decrease larval settlement, compared to the positive settlement control. The equivalent concentration of Brand X significantly inhibited larval settlement.

Tests Summary of Biodegradable Sunscreens and Products

We set out to create the safest product line of biodegradable sunscreens and bodycare possible for us and the environment. Our company is led by a vegetarian and an animal rights activist, yet we realized that the only way to determine if our products would be harmful to fish and other aquatic life was to test them on living animals. Read more about the tough decisions we’ve had to make about product testing through the process here.  In the end, we are very proud of the SAFE products that we have created. You can feel good using our products during all your adventures, in the backyard or while exploring our beautiful planet blue.

Particle Size Distribution

Stream2Sea biodegradable and reef safe mineral sunscreens are independently verified to contain only NON-NANO particles of titanium dioxide. The X-Axis on these charts are in microns. 100 nanometers equals 0.1 micron. Both plots show nothing below 100 nanometers or 0.1 microns.

Scientific Tests and Resources

Scientific Test Results


  • 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. Archives of Environmental Contamination and Toxicology. Downs C.A. et al. 2015 October. Summary of test results.  Also: Full Text.
  • Sunscreens Cause Coral Bleaching by Promoting Viral Infections. Environmental Health Perspectives. Danovaro R, et al. 2008 April. Full Text
  • The Impacts of Sunscreens on Our Coral Reefs. National Park Service. Sunscreen Bulletin