3. NanoparticlesPhoto credit: Smithsonian Institute
Largely untested, these extremely minuscule particles are usually undeclared on product labels, even though they can be absorbed directly into the bloodstream. In addition to bronzers, eye shadows, and lotions, you can also find them lurking in a large number of sunscreens that use micronized particles of zinc oxide and titanium dioxide, which form physical barriers against UV rays. It's on this battlefield that the "nano wars" are at their most feverish.
Although the EWG, after poring over 400 peer-reviewed studies, concluded that the benefits of small-scale zinc and titanium sunscreen ingredients outweighed the potential risks, a recent report by Friends of the Earth, Consumers Union (publisher of Consumer Reports), and International Center for Technology Assessment had a different take. "Consumers must be aware that nanomaterials are being put into sunscreens with very little evidence about their safety and relative efficacy," notes Ian Illuminato, one of the report's co-authors, citing a 2007 Consumer Reports test that the EWG found at odds with its own investigation—at least for liquid sunscreens.
Powdered sunscreens or sprays, which can be inhaled, are a whole different story, however. The high surface area—and high reactivity—of tiny particles of zinc and titanium can provoke inflammatory responses, oxidative stress, and cell damage.
4. PhenoxyethanolPhoto credit: sakura_chihaya
A ubiquitous preservative, even in products touted as "all-natural" or "organic," phenoxyethanol is classified as an irritant by the European Union and a restricted substance in Japanese cosmetics. According to its Material Safety Data Sheet, which refers to 100 percent concentration, phenoxyethanol is not only harmful if inhaled, swallowed or absorbed through the skin, but it can also cause reproductive defects and nervous system damage. In cosmetics, concentrations are typically less than 1 percent, but your exposure to the ingredient could be compounded depending on how often it rears its head in the products you use.
Let's put it this way, if phenoxyethanol is awful enough for the U.S. Food and Drug Administration, which has a spotty record at best when it comes to championing public interest, to put out a consumer alert warning that it can "depress the central nervous system and may cause vomiting and diarrhea" in infants, it's probably wise to steer clear of this bad boy.
5. TriclosanPhoto credit: monsieurlui Triclosan is an antibacterial compound that runs rampant in many cleansers, deodorants and other personal-care products that the U.S. Environmental Protection Agency classifies as a probable human carcinogen. Linked to cancer, developmental defects, and liver and inhalation toxicity, overuse of this hormone-disrupting pesticide—yes, pesticide—can also result in strains of drug-resistant superbacteria.
Plus, triclosan tends to bioaccumulate in the fatty tissues of people and animals, which explains why it's been detected in our blood and breast milk. Acutely toxic to several types of aquatic life, triclosan can also degrade into a form of dioxin, a class of known carcinogens. New research also shows that triclosan in tap water can react with residual chlorine from water disinfection to form myriad chlorinated byproducts, including chloroform, a human carcinogen.