Environmental Impact

Why It Matters

There are two different types of active sunscreen ingredients: chemical UV absorbers (which absorb rays that come in contact with skin) and physical UV blockers (which reflect rays before they can do any damage).

Most of the concerns around sunscreens have to do with the chemical UV absorbers. The same chemicals that interfere with human hormones were recently found to cause bleaching and death of corals. Seventy-eight million tourists visit areas with coral reefs every year, leaving behind 4,000 to 6,000 tons of sunscreen-and because many sunscreens are petroleum-based, they don't break down quickly in water. An April 2008 study published in Environmental Health Perspectives revealed that, when exposed to benzophenone or cinnamate-based sunscreens, coral developed viral infections that led to bleaching. The same happened when coral were exposed to paraben preservatives.

Many chemical UV absorbers have been found to act like estrogen in the body: benzophenone, oxybenzone, octinoxate (also called octyl methoxycinnamate) and homosalate are all chemical sunscreens to avoid for this reason. There's also evidence that the chemical Avobenzone (also called Parsol 1789) degrades quickly when exposed to sunlight, and according to a 2007 report from the Environmental Working Group, many chemical sunscreens break down in as little as 30 minutes when exposed to sunlight.

In a 2004 Environmental Health Perspective study, another sunscreen chemical, Padimate O, was found to cause breast cancer cells to multiply in test tubes. Benzophenone may also cause allergic reactions, and all of these chemical sunscreen ingredients have been found to increase skin absorption of pesticides on people who were wearing them during pesticide application.

Along with all the active chemical ingredients, sunscreens also contain many ingredients listed on our "Dirty Dozen" list of chemicals to avoid. Allergenic synthetic dyes and fragrances that contain hormone-disrupting phthalates are common, as are parabens (preservatives that also act like estrogen in the body) and urea preservatives that emit formaldehyde as they break down.