Today there is a general consensus amongst scientists that most chemical sunscreens we use harm coral reefs and other marine life. According to Craig Downs, the executive director of non-profit scientific outfit Haereticus Environmental Laboratory, the damage “can be bigger than climate change”.  There is a good alternatve, mineral sunscreens including zinc oxide or titanium dioxide that are “non-nano” in size are considered safe. So this is something that we, as a consumer, can control directly! 

Oxybenzone or benzophenone-3, a common chemical found in most chemical sunscreens, is one of the worst performers. It is toxic to the symbiotic algae that live within corals (which performs vital duties to the coral polyps) and it stunts the growth of corals. Oxybenzone damages coral DNA, causes deformities on the coral, initiates endocrine disruption (= interference with hormone systems) and makes coral more susceptible to coral bleaching. It also has a negative impact on the well-being of other marine life like fish, invertebrates, shellfish, etc.

The damaging effect of oxybenzone can occur in concentrations as low as 62 parts per trillion. This is equivalent to one drop of oxybenzone in six Olympic-sized swimming pools. An estimated 14.000 tons of sunscreen is deposited in the world’s oceans each year killing reefs and other marine life. Harmful are not only the chemicals that come off while swimming but also what travels through sewage systems when washed off in the shower. Also, as the chemicals are absorbed by our skin and excreted by urine, they end up in the ocean eventually through this route. 

Oxybenzone, also called benzophenone-3 (trade names Milestab 9, Eusolex 4360, Escalol 567, KAHSCREEN BZ-3), is not the only wrong-doer. There are more chemicals in many sunscreens that can damage the reef and marine life. Screening chemical sunscreen for environmental friendliness requires more research on other chemicals that it contains like octinoxate, methyl paraben and many more. You can use as a guide a checklist of known environmental pollutants the Haereticus Environmental Laboratory published (unfortunately in the ingredient lists on sunscreens many synonyms are used for the chemicals):

  • oxybenzone (=benzophenone-3),
  • octinoxate (=ethylhexyl methoxycinnamate)
  • 4-methylbenzylidene camphor (=Enzacamene or 4-MBC),
  • octocrylene,
  • para-aminobenzoic acid (PABA),
  • methylparaben,
  • ethylparaben,
  • propylparaben,
  • butylparaben,
  • benzylparaben,
  • triclosan,
  • homosalate,
  • octisalate,
  • any form of microplastic sphere or beads,
  • any nano-particles.

As a good alternative mineral sunscreens including zinc oxide or titanium dioxide that are “non-nano” in size are considered safe. Important to check the ‘’non-nano’’ of these products which explains the particle size. Smaller particles (‘nano’) can be ingested by the coral polyps and are still harmful. Needless to say, using good protective clothing and staying less in the sun is even a better idea.

Mexico, Hawaii
In Mexico, areas popular with snorkelers such as Xel-Há on the Rivera Maya and Chankanaab Beach Adventure Park in Cozumel ban the use of non-biodegradable sunscreen. At the seven Solmar Hotels & Resorts in Los Cabos, guests may purchase biodegradable sunscreen on-site and are advised in advance that it is the only kind permitted in area preserves such as Cabo Pulmo National Marine Park.  A bill to ban the sale of sunscreens containing oxybenzone and octinoxate was passed by the Hawaii state legislature in May 2018 and will now go to the governor’s office for his signature. If signed, the ban would start in 2021. Hawaii is set to become the first state in the US to ban the sale of sunscreen chemicals that are toxic to coral reefs and marine life.


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