This is the first post in our upcoming series on harmful chemicals found in our everyday skin and beauty products.

1.  BHA (butylated hydroxyanisole)

BHA, or butylated hydroxyanisole, is a common food, medicine and cosmetic product additive. It’s purpose? Keeping products fresh for longer. The problem? According to the Environmental Working Group, BHA ingestion and exposure “produces liver damage and causes stomach cancers…and interferes with normal reproductive system development and thyroid hormone levels” in animals. Based on these findings, the U.S. National Institutes of Health suggest that BHA may also cause cancer and other problems in humans.

So, how do you avoid BHA? As with all potentially harmful chemicals, carefully examine the ingredient lists on products before purchasing. Look for “BHA” or “butylated hydroxyanisole.” The top 5 products most likely to contain BHA, according to the Environmental Working Group, are lipsticks, foundations, makeup containing sunscreen, nail polish, and mascara. Be especially careful with products like lipsticks, which are easily ingested, and body creams, which are generally used in larger quantities on your skin.

2.  Boric Acid and Sodium Borate

New moms and dads, take note: boric acid, an ingredient found in some diaper creams, is known to harm the male reproductive system (read: infertility) and has been linked with cancer in laboratory animals. It has not yet been claimed a human carcinogen, but its carcinogenic results in animals and the ease with which it is absorbed into the skin are of concern. Though some places, including Canada and the European Union, have restricted boric acid’s use in infant care products, no restrictions are currently in place in the United States.

Though diaper creams are a primary concern, boric acid and sodium borate are also found in some moisturizers and bath products meant for adults. Be especially attentive to the ingredient lists on body creams, bath oils, bath salts, and bubble bath products. If you do have any boric acid-containing products, you should be especially careful to avoid using them on broken or damaged skin, as the compound already absorbs quickly and even greater quantities are absorbed when skin is damaged.

3.  Coal Tar

Coal tar is a common ingredient in hair products, especially hair dyes and dandruff and psoriasis shampoos. According to the Environmental Working Group, both the National Toxicology Program and the International Agency for Research on Cancer have named coal tar a known human carcinogen. The risk is especially high for hair stylists, who are frequently exposed to hair dyes.

You should be particularly careful about your use of and exposure to dark, permanent hair dyes. Wherever possible, identify salons that use natural, coal tar-free hair dyes, or avoid coloring your hair altogether.

Also be wary of shampoos and medicated body lotions that list coal tar as a primary ingredient. Shampoos intended to treat or alleviate the symptoms of dandruff and psoriasis often contain coal tar, as it helps the scalp shed dead skin cells and soothes itching. These properties also make coal tar a useful ingredient in some eczema and atopic dermatitis lotions and medications. Though the FDA has allowed the use of coal tar in these products, there aren’t any conclusive tests about its safety, and its known carcinogenic qualities make the long-term effects of these products a concern.

Stay tuned for future posts on more harmful ingredients to be aware of as you shop for new skin and beauty products.