Protecting Reefs: The Lethal Impact of Sunscreens

on Mar 04, 2023
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Coral reefs are some of the most beautiful and diverse ecosystems on Earth, but they are threatened by various human activities, including sunscreen. While sunscreen is a vital tool for protecting our skin from sun damage, many of the chemicals found in sunscreen can have a lethal impact on reef organisms, contributing to the decline of coral reefs worldwide.

This article will explore how sunscreens can be lethal to reef organisms and provide solutions for protecting these ecosystems.

The Impact of Sunscreens on Reef Organisms

Sunscreen contains chemicals that harm reef organisms, including coral, algae, and fish. Here are some of how these chemicals can be lethal:

1. Coral Bleaching 

Many sunscreen ingredients, such as oxybenzone and octinoxate, have been linked to coral bleaching, which is the loss of color in coral reefs that can lead to coral death. Coral bleaching occurs when corals become stressed, often due to water temperature or pollution changes, and expel the algae that live inside them. These algae provide the coral with essential nutrients; without them, the coral becomes vulnerable to disease and death.

2. Algae Growth 

Some sunscreen ingredients can promote the growth of algae, which can smother and kill coral reefs. Algae growth is especially prevalent in areas with a high concentration of nutrients in the water, such as near sewage outfalls or agricultural runoff.

3. Hormone Disruption 

Some sunscreen ingredients, such as oxybenzone, can disrupt the hormones of fish and other reef organisms, leading to developmental abnormalities and reproductive issues.

4. Toxicity 

Many sunscreen ingredients are toxic to reef organisms, including fish, algae, and invertebrates. These toxins can build up in the food chain, leading to further ecological impacts.

Protecting Reefs from Sunscreen Lethality

Fortunately, there are several steps that we can take to protect reef organisms from the lethal impacts of sunscreen:

Choose Reef-Safe Sunscreens

Look for sunscreens that do not contain harmful chemicals, such as oxybenzone, octinoxate, and other chemicals on the "no no" list (see below). Instead, choose sunscreens that use mineral-based UV filters, such as zinc oxide or titanium dioxide, which are less harmful to reef organisms and the environment.

Limit Sunscreen Use 

While wearing sunscreen is important for protecting your skin from sun damage, limiting your use of sunscreen as much as possible when near reef ecosystems is also important. Consider wearing protective clothing, such as a rash guard or hat, and staying in the shade during peak sun hours to reduce your need for sunscreen further.

Practice Safe Snorkeling and Diving

When snorkeling or diving, always follow responsible practices, such as avoiding contact with marine life, using reef-safe anchors, and properly disposing of trash or waste.

Avoid Sunscreens With These Ingredients

Many commonly used sunscreen ingredients can harm coral reefs and other marine life. Here is a list of some of the most harmful sunscreen ingredients that you should avoid when choosing a sunscreen to use near reefs:

  •  Oxybenzone (Benzophenone-3)
  • Octinoxate (Ethylhexyl methoxycinnamate)
  • Octocrylene
  • Homosalate
  • Butylparaben
  • Octisalate (Ethylhexyl salicylate)
  • 4-Methylbenzylidene camphor (4MBC)
  • Benzyl salicylate
  • Cinnamate
  • Cyclohexene carboxylate
  • Diethylhexyl 2,6-naphthalate (Mexoryl SX)
  • Padimate O (Octyl dimethyl PABA)
  • Phenylbenzimidazole sulfonic acid (Ensulizole)
  • Sulisobenzone (Benzophenone-4)


To protect coral reefs from the lethal impact of sunscreen, it is important to choose reef-safe sunscreens that do not contain harmful chemicals, such as oxybenzone and octinoxate, and to limit our use of sunscreen as much as possible when near reef ecosystems.

Additionally, practicing responsible snorkeling and diving and supporting reef conservation efforts can help to preserve these vital ecosystems for future generations. These steps can help ensure that coral reefs continue to thrive and provide important benefits for marine life and human communities worldwide.