Aluminum: used mainly in anti-perspirants to prevent sweating. Aluminum affects the central nervous system and is linked to Alzheimer’s disease.

Boric acid and sodium borate: These chemicals disrupt hormones and harm the male reproductive system. Men working in boric-acid-producing factories have a greater risk of decreased sperm count and libido. In animals, high doses cause testicular damage in mice, rats and dogs. Both the EU and Canada restrict these ingredients in body care products made for children under 3 years of age and require that products containing these ingredients be labeled as not appropriate for broken or damaged skin. No similar safety standards are in place in the U.S. The cosmetic industry’s own safety panel states that these chemicals are unsafe for infant or damaged skin, because they can absorb readily into the body. Despite this guidance, boric acid is found in some diaper creams.

Butylated hydroxyanisole (BHA): The National Toxicology Program classifies BHA as “reasonably anticipated to be a human carcinogen.” In animal studies, BHA produces liver damage; causes stomach cancers such as papillomas and carcinomas; and interferes with normal reproductive system development and thyroid hormone levels. It is found in food, food packaging and personal care products sold in the U.S.

Coal tar hair dyes and other coal tar ingredients (including aminophenol, diaminobenzene and phenylenediamine): Coal tar, a byproduct of coal processing, is a known human carcinogen, according to the National Toxicology Program and the International Agency for Research on Cancer. Europe has banned many of these ingredients in hair dyes. Although FDA sanctions coal tar in specialty products such as dandruff and psoriasis shampoos, its long-term safety has not been demonstrated.

DEA, TEA & MEA: solvents and emulsifiers found in shampoos, conditioners, moisturizers, shaving gels, bubble bath and skin cream. DEA, TEA and MEA can cause allergic reactions and may be linked to cancer. 

Formaldehyde: A potent preservative classified as a “known human carcinogen” by the International Agency on Research on Cancer. Formaldehyde, also an asthmagen, neurotoxicant and developmental toxicant, was once mixed into many personal care products as an antiseptic. This use has declined. But some hair straighteners contain substantial amounts of formaldehyde and release potentially toxic fumes during their use.

Formaldehyde releasers (Bronopol, DMDM hydantoin, diazolidinyl urea, imidazolidinyl urea and quaternium-15): Cosmetics preservatives that slowly form formaldehyde, a known human carcinogen, within the product to kill growing bacteria. These preservatives and the formaldehyde they generate can trigger allergic skin reactions. Formaldehyde releasers are widely used in U.S. products.

“Fragrance”: Federal law doesn’t require companies to list on product labels any of the chemicals in their fragrance mixture. Research from EWG and the Campaign for Safe Cosmetics found an average of 14 chemicals in 17 name-brand fragrance products, and none of them was listed on the label. Fragrances can contain hormone disruptors and are among the top five allergens in the world. Our advice? Look for products that disclose their fragrance ingredients.

Hydroquinone: A skin-bleaching chemical that can cause a skin disease called ochronosis, which is characterized by blue-black lesions that in the worst cases become permanent black caviar-size bumps. In animal studies, hydroquinone has caused tumor development.

Lead and Lead acetate: A neurotoxin in popular black hair dyes and men’s progressive hair dyes, such as Grecian Formula 16.

Methylisothiazolinone (MI/MIT), methylchloroisothiazolinone (MCI) and benzisothiazolinone (BIT):Preservatives, commonly used in personal care products, that are among the most common irritants, sensitizers and causes of contact allergy.

Mineral Oil: a byproduct of petroleum refinement and is used in cosmetics such as liquid foundation, blush, skin creams and baby oil to make skin feel smooth. Mineral oil clogs pores, preventing skin from eliminating toxins, leading to skin break outs, acne and other skin disorders.

Nanoparticles: Zinc oxide and titanium dioxide nanoparticles appear to be among the safer and more effective active ingredients in U.S.-marketed sunscreen creams, because they do not penetrate intact skin. But avoid sprays and powders containing these nanoparticles, which could be inhaled and enter the lungs and bloodstream. Many other nanoparticles have received very little testing, yet they readily penetrate the skin and contaminate the body. Cosmetics manufacturers are not required to disclose the presence of nanoparticles in their products.

Oxybenzone: Sunscreen agent and ultraviolet light absorber, found in the bodies of nearly all Americans, according to the U.S. Centers for Disease Control and Prevention. In human epidemiological studies, oxybenzone has been linked to irritation, sensitization and allergies. A study of more than 400 New York City women in the third trimester of pregnancy associated higher maternal concentration of oxybenzone with a decreased birth weight among newborn baby girls but with greater birth weight in newborn boys. Studies on cells and laboratory animals indicate that oxybenzone and its metabolites may disrupt the hormone system.

Parabens (specifically propyl-, butyl-, isopropyl-, and isobutyl- parabens): Parabens are widely used as preservatives in cosmetics. The CDC has detected parabens in virtually all Americans. According to the European Commission’s Scientific Committee on Consumer Products, certain parabens (propyl-, butyl-, isopropyl-, and isobutyl-), may disrupt the endocrine system and cause reproductive and developmental disorders.

PEGs and ceteareth: A family of conditioning and cleaning agents that go by many names. These synthetic chemicals are frequently contaminated with 1,4-dioxane, which the U.S. government considers a probable human carcinogen and which readily penetrates the skin.

Petroleum distillates: Petroleum-extracted cosmetics ingredients may cause contact dermatitis and are often contaminated with cancer-causing impurities. They are produced in oil refineries at the same time as automobile fuel, heating oil and chemical feedstocks.

Phthalates: A growing number of studies indicate that the chemical family of phthalates damages the male reproductive system. Pregnant women should avoid nail polish containing dibutyl phthalate. Everyone should avoid products with “fragrance,” which indicates a chemical mixture that may contain phthalates.

Propylene Glycol: used for hydration in soaps, shampoos, cleansers and other cosmetics. Propylene glycol can cause severe skin rashes and contact dermatitis. It can cause damage to the kidneys and liver, as well as neurotoxicity in children. 

Resorcinol: A common ingredient in hair color and bleaching products that has been linked to skin irritation and immune system dysfunction and is a frequent cause of hair dye allergy. In animal studies, resorcinol can disrupt normal thyroid function.

Sodium Lauryth Sulfate (SLS): lathering agents that make soaps foam and create suds. SLS can cause severe skin irritation and can build up in the heart, lungs, liver and brain. It can contaminated with 1,4-dioxane, a known carcinogen.

Talc: used to absorb moisture in products containing powder. Talc is linked to cancer and can cause irritation when inhaled.

Toluene: Volatile petrochemical solvent and paint thinner and potent neurotoxicant that acts as an irritant, impairs breathing and causes nausea. A pregnant woman’s exposure to toluene vapors during pregnancy may impair fetal development.

Triclosan and triclocarban: Antimicrobial ingredients in a range of personal care products, including toothpaste and deodorant. Often found as contaminants in people due to widespread use of antimicrobial personal care and cleaning products. These ingredients are linked to endocrine disruption; triclosan affects thyroid function and proper functioning of reproductive hormones. They are also very toxic to the aquatic environment. The American Medical Association and the American Academy of Microbiology say that soap and water serves just as well to prevent the spread of infections and reduce bacteria on the skin. Overuse may promote the development of bacterial resistance.