Secret ingredient: Some cleaners contain carcinogens not listed on the label.

RODALE NEWS, ANAHEIM, CA—Among ecosavvy vendors and health nuts at Natural Products Expo West earlier this month, the term “1,4-dioxane” popped up in conversations like it was a household name. It isn’t, but the substance is probably inside most of our homes—it can be found in many detergent, shampoos, cosmetics, and soaps. And, considering the chemical is a suspected cancer causer, you could call it a dirty little secret.

THE DETAILS: The U.S. Department of Health and Human Services considers 1,4-dioxane as “reasonably anticipated” to be a human carcinogen. Manufacturers aren’t deliberately adding the stuff into your detergent, cosmetics, and shampoo products, but it is a by-product of some of the other chemical ingredients they use. Unfortunately, you won’t see the contaminant listed on any label. Cleaning products like detergents and dishwashing gels aren’t required by law to list any ingredients. Personal care items do need be labeled, but since 1,4-dioxane is a contaminant and not an ingredient, you won’t see it listed on them either. But the toxin may be there just the same. For instance, a new report from The Campaign for Safe Cosmetics found 1,4-dioxane in 67 percent of the children’s bath and personal care products they tested.

WHAT IT MEANS: The effect of 1,4-dioxane on humans hasn’t been well studied, but animal studies have linked exposure to liver and kidney damage and cancer, and that apparently was enough for the government to list it as an anticipated human carcinogen. Even though the amount of the trace contaminant in any given product is usually small, there’s concern about exposure because scientists are finding it in so many products. Last summer, for example, Rodale.com advisor Anne Steinemann, PhD, professor of engineering at University of Washington in Seattle, found 1,4-dioxane and other potentially toxic chemicals in several popular scented laundry products. (She plans to test more products in the future, and did not release the brand names of the 6 products tested.)

Here’s how to find less toxic cleaners and personal care products: