The state of the world’s coral reefs will be under the spotlight next month at the thirteenth International Coral Reef Symposium (ICRS) in Hawaii.

Whilst assessing the impact of climate change and agricultural pollution on coral structures, scientists will be looking at a less-well known threat – pollution of the marine environment by personal care products (PCPs), including sunscreen.

Most people are aware of the need to protect their skin from the sun especially while in or near water, but few realise that one of the ways of achieving this – sunscreen – is putting corals at risk. The majority of sunscreen products contain chemicals which can cause serious harm to marine life. 

The problem arises because ingredients contained in personal care products enter the ocean either directly from swimmers’ skin, showers or through chemicals transported in our sewage systems. Researchers behind a study, published in the journal Archives of Environmental Contamination and Toxicology last October, found that one such chemical, oxybenzone, has a toxic effect on young coral, causing endocrine disruption, DNA damage and death. In essence, it poses a major ecological conservation crisis because it prevents new corals from populating an area.

The majority of sunscreen products contain chemicals which can cause serious harm to marine life. 

Oxybenzone also exacerbates coral bleaching, a process by which coral reject symbiotic organisms and lose their colour. Bleaching has been particularly prevalent in recent years due to rising sea temperatures. This chemical lowers the temperature at which coral bleaches and reduces their ability to reproduce and rebuild the community afterwards. Oxybenzone is toxic to more than just coral – it’s toxic to algae, sea urchins, fish and mammals. 

Facts about Oxybenzone

  • Oxybenzone is found in more than 3,500 sunscreen products worldwide, as well as lipstick, mascara and shampoo
  • Oxybenzone acts as a barrier to UV light and is entirely replaceable by other, less marine-toxic ingredients
  • Baby coral exposed to field-realistic concentrations of oxybenzone encase themselves in their own skeleton and die
  • One drop of oxybenzone in the equivalent of six-and-a-half Olympic-size swimming pools’ worth of water is sufficient to damage coral
  • Levels of oxybenzone in seawater around coral reefs in Hawaii and the US Virgin Islands were found to be 12 times higher than the concentration that damages baby coral
  • Oxybenzone can cause behavioural problems in fish, making them not only less territorial, but less likely to drive off predators
  • Oxybenzone causes feminization in fish, causing male fish to turn into females, and causing a number of female reproductive diseases
  • There are a number of concerns about the effect of oxybenzone on human health and it is on the EU’s ‘Substitute It Now’ list of substances that should be replaced and meets the criteria for ‘Substances of Very High Concern’

A related problem is the inclusion of plastic microbeads in some products. These persist in the ocean environment for thousands of years and act as a magnet to some pollutants that bind to them. Scientists have been concerned about some of these chemical ingredients for a number of years and there is a growing body of literature on the subject. The relevant reports and the pollutants and the names they may appear under on a list of ingredients can be found here.

The International Programme on the State of the Ocean (IPSO) and the International Union for the Conservation of Nature (IUCN) and the World Commission on Protected Areas held a specialist workshop in Oxford last month concentrating on pollution from domestic sources. They agreed to review the existing literature and make recommendations for governments and manufacturers about this escalating cause of ocean degradation. IPSO’s lead scientists are working with policy experts to draw on these findings to develop a stringent new certification scheme for sunscreens, and PCPs in general, which are free from so-called marine-toxic chemicals.

- This is a guest blog and may not represent the views of Please see for more details.