Sunscreen & Reefs. Who me?

Star Coral

Star Coral

The facts about sunscreens and their impact on our reefs are out there. And they are confusing. And until everyone starts agreeing and saying the same thing, it’s very easy for us to keep to our old habits. I’ve grabbed some of the more relevant tidbits that would be of interest to snorkelers and kind of compiled them. I too find this stuff confusing, frightening and simultaneously train wreck fascinating.

“Most Caribbean coral reefs may disappear in the next 20 years”- GCRMN, IUCN and UNEP

About 5000 metric tons of sunscreen wash off swimmers and into our oceans every year.

Mexico has a federal law allowing only biodegradable sunscreen use during snorkeling, scuba or any water activity inside Cozumel’s protected marine park or at the marine parks of Chankanaab, Xcaret, Xel Ha, and Garrafon.  All non-biodegradable sunscreens are prohibited.


INGREDIENTS in Sunscreens to avoid if possible:

AVOID: 4 Chemicals that are linked to reef viruses and coral bleaching: (bad)

    • Oxybenzone (benzophenone-3)
    • Butylparaben 
    • Octinoxate (Ethylhexyl methoxycinnamate)
    • 4-methylbenzylidene camphor (4MBC)

AVOID: 2 Chemicals that studies show are linked to creating hydrogen peroxide harmful to phytoplankton one of the most important food sources for ocean life. (less bad?)

    • Titanium dioxide
    • Zinc oxide

When choosing a product, Be aware of False Labeling – Reef Friendly, natural or eco-friendly labels may or may not be accurate. Read the ingredients. There are no organizations monitoring and rating reef friendly products. So be careful.

The EWG has a 2015 report and rating for all brands of sunscreen. But after finding a low rating you’ll still need to check for our unfriendly 6 chemicals. Environmental Working Group Sunscreen Help Check out your current sunscreen’s rating. (In the future choose something with a low (0 -2) EWG rating.)


Seems anything above SPF 30 is a concentrated waste of chemicals.

  • SPF 15 filters out approximately 93% of all incoming UVB rays.
  • SPF 30 filters out approximately 97% of all incoming UVB rays.
  • SPF 50 filters out approximately 98% of all incoming UVB rays.
  • SPF 100 filters out approximately 99% of all incoming UVB rays.

Bad practices – Sun screen should be applied at least 20 minutes before going into the water. It needs time to be absorbed by your skin. If you are slathering up right before you go snorkeling, you might as well just dump the sunscreen right in the water as it will just be washed off. (Remember those 5000 tons)

  • Water-resistant sunscreens lose their SPF after 40 minutes in the water.
  • Waterproof sunscreens lose their SPF after 90 minutes in the water.

I am trying. But what am I left with? No one is saying stop using sunscreen. (yet.)

  • Try to avoid the chemicals mentioned. Or pick one with as few as possible.
  • Use lotion on the beach and a long sleeved rash guard (water shirt) when snorkeling.
  • Look for Reef Safe / eco friendly but make sure it is reef safe and not labeling hype. (Ingredients!)
  • Look for Biodegradable 
  • Most importantly no matter what brand, apply 20 minutes or more before going in the water to minimize wash off. Lets get that 5000 tons down to 4000.

LIST of Potential Sun Screens  Danielle put together a list of sunscreens and their ingredients that is very helpful. 

This is not a finger pointing exercise.  More of an educational undertaking. (Except for the bit about Mexico being way more protective of their reefs then us. I can’t help but feel slightly embarrassed about that.) SO, if you find or have found one sunscreen product you like. Please share your discovery here.

-Capt Wilson

Repeat Offenders: I stumbled across this quote from the EWG which made my day:

“EWG’s Sunscreen Hall of Shame draws attention to products that promise safe sun protection and don’t deliver. This year, one brand stands out – Neutrogena.”  

Can you say Umbrella Corp.

To see photos of coral that may or may not be around in 20 years click here.

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