Bay Crossings Article

Say Yes to Mineral Sunscreens, but No to Nanos

Deb Self, Executive Director
From the July 2011 edition of Bay Crossings

America’s 33-year wait for the FDA to publish rules on sunscreen labeling ended in June—just in time for the apparent end of the rainy season. The new rules go into effect next year and will provide clear guidance for the most part on sunscreen manufacturers’ claims about effectiveness.

Until then, you’ve got a few tools to help you choose a sunscreen that does more good than harm. It was only a few years ago that I learned about some surprising health and environmental risks that sunscreen ingredients can pose to people and to the Bay. I wanted to share share some recent research by Environmental Working Group (EWG) about which sunscreens pose the greatest risk to human health, and also explain Baykeeper’s take on how to protect the aquatic ecosystems you’re likely to splash around in this summer.

There are two main types of sunscreen: chemical and mineral. The majority of chemical sunscreens contain dangerous compounds that can cause cancer and disrupt hormones. The chemical used most widely in the United States for sunscreen protection is oxybenzone (or benzophenone-3). It has been detected in 96 percent of people whose urine and blood have been tested for it, and has been widely found, along with other sunscreen chemicals, in mothers’ milk.

Experts caution parents not to use oxybenzone on children. Despite the warning, many chemical sunscreens branded for babies contain oxybenzone, which may cause reproductive problems, organ system toxicity, cellular level changes and bioaccumulation in the food web. Many chemical sunscreens also contain Vitamin A (retinyl palmitate or retinol), which appears to contribute to skin tumors when applied in sunlight.

Instead, EWG and other environmental groups recommend mineral sunscreens with zinc oxide or titanium oxide, because they don’t appear to absorb deep into the body, don’t break down in sunlight and pose a lower health risk. Local sewage treatment plants also generally can remove natural minerals from the waste stream.

This advice comes with one important caveat. Increasingly, sunscreens are using nano-particles of zinc and titanium in their formulations, which Baykeeper urges you to avoid if possible. The results of several recent studies suggest that nano-zinc is toxic to human colon cells, harms brain stem cells in mice, and accumulates in the food chain, where it is likely to be toxic to many aquatic life forms. Protect your kids, your skin and the Bay’s sensitive food web by choosing mineral sunscreens that don’t use nanoparticles.

Unfortunately, there is no labeling requirement for nanoparticles, but some brands are starting to advertize that their sunscreens are nano-free. In general, it might be a good idea to avoid mineral sunscreens whose labels claim a transparent formula. Manufacturers achieve the illusion by using tiny engineered particles of zinc and titanium that are so small—between one and 100 microns in diameter—they’re basically invisible.

When you choose a nano-free, mineral sunscreen, you’re not only protecting your health, but the Bay’s ecosystem as well. Remember that any chemical that washes off in the shower ends up in the Bay, because our sewage treatment plants generally can’t remove the chemicals in personal care products.

You can read more about Baykeeper’s work to protect the Bay at Search for health information on lotions, sunscreens and cosmetics in the Skin Deep database at