August 20, 2020 3 min read

There’s been lots of coverage in the news about sunscreen’s effect on marine life, and in particular the delicate ecosystems found in coral reefs like the Great Barrier Reef. For example, the State of Hawaii is banning sunscreens containing two ingredients – oxybenzone and octinoxate (commonly known as octyl methoxycinnamate in Australia).

Let’s check the science for you.

Experts don’t agree

The Hawaii ban followed the publication of a specific scientific study (1), which focused on the potential impact of oxybenzone on coral and measured levels of this sunscreen ingredient in certain places along Hawaii’s coastline. The results implied that that chemical could have a potential impact on coral at low concentrations and that similar concentrations were present in particular places along the coast (2).

Several experts though say there is still a lack of in-depth research on the subject. Marc Leonard, head of L’Oréal’s Research & Innovation, Environmental Research department, said in The Scientific American – “Regulatory decisions have to be made on sound scientific evidence and multiple studies. They have to be completed by different teams to provide a significant bundle of evidence. We are very far from it in this case.”

In Australia the Therapeutics Goods Administration (TGA) is also yet to believe that there is sufficient evidence to remove such ingredients from sunscreens on the Australian market.

Even if the concerns over oxybenzone on coral is supported by further independent research, it may have little impact on Australia’s coastline, with this particular ingredient only found in a small proportion of sunscreens in our market (Maxiblock sunscreens don’t use any oxybenzone for example).

‘Natural’ sunscreens may not be a better choice

Most so-called ‘natural’ sunscreens use high concentrations of zinc oxide, a man-made chemical, as the primary UV filter. Zinc oxide is well-known for its strong UVA absorption properties. What is less known is that zinc oxide is partly water-soluble and classified as an ecotoxic: its Safety Datasheet typically says: ‘very toxic to aquatic organisms, may cause long-term adverse effects in the aquatic environment’. (4)

There is however currently not enough information on the marine impact of zinc-oxide containing sunscreens to suggest avoiding this ingredient on the beach or in the water.

Australian 4-hour water-resistant sunscreens best suited

The Australian sunscreens meeting the exceptionally stringent Australian 4-hour water resistant standard (e.g. Essential by Maxiblock) are designed to stay longer on the skin and not wash off easily. This means that the amount of UV filter dispersing into the water will be significantly less compared to sunscreens without water resistance or those meeting only the US or European standards.

In summary

The current situation is probably best put into perspective by one of Australia’s most recognised experts on the Great Barrier Reef, Professor Terry Hughes from James Cook University. “People make a long list of bad things that human beings do to coral reefs — I would place sunscreen at number 200″ (3).

Our view is that it’s too early to call out specific UV filters as the science is not settled yet. We do recommend using an Australian sunscreen labelled SPF 50+ with 4-hours water resistance when going in the water.

1. https://www.theguardian.com/travel/2018/may/03/hawaii-becomes-first-us-state-to-ban-sunscreens-harmful-to-coral-reefs

2. 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. https://link.springer.com/article/10.1007%2Fs00244-015-0227-7

3. Hawaii bans sunscreens with chemicals that damage coral reefs, but Australia reluctant to follow. https://www.abc.net.au/news/2018-05-04/hawaii-bans-sunscreen-coral-bleaching/9728322

4. http://www.uszinc.com/assets/uploads/2018/02/US-Zinc-SDS-ZnO-Rev12.pdf