Reef Safe classification can only be achieved if a sunscreen uses ONLY non-nano Zinc Oxide as its active ingredient.Sunscreens that are Reef Friendly still contain ingredients such as Titanium Dioxide and certain chemical ingredients that have potential to harm our reefs. Although Titanium Dioxide acts as a mineral barrier for sun protection, it can become unstable in water, losing its protective coating and becoming toxic to coral reefs and aquatic life. Many sunscreens that use only Zinc still include chemical ingredients (other than Oxybenzone and Octinoxate) that are also shown to be harmful to our waterways.