As a byproduct of the ethoxylation process, a route to some ingredients found in cleansing and moisturizing products, dioxane can contaminate cosmetics and personal care products such as deodorants, perfumes, shampoos, toothpastes and mouthwashes. The ethoxylation process makes the cleansing agents, such as sodium laureth sulfate and ammonium laureth sulfate, less abrasive and offers enhanced foaming characteristics. 1,4-Dioxane is found in small amounts in some cosmetics, a yet unregulated substance used in cosmetics in both China and the U.S. Research has found the chemical in ethoxylated raw ingredients and in off-the-shelf cosmetic products. The Environmental Working Group (EWG) found that 97% of hair relaxers, 57% of baby soaps and 22 percent of all products in Skin Deep, their database for cosmetic products, are contaminated with 1,4-dioxane.
Since 1979 the U.S. Food and Drug Administration (FDA) have conducted tests on cosmetic raw materials and finished products for the levels of 1,4-dioxane. 1,4-Dioxane was present in ethoxylated raw ingredients at levels up to 1410 ppm (~0.14%wt), and at levels up to 279 ppm (~0.03%wt) in off the shelf cosmetic products. Levels of 1,4-dioxane exceeding 85 ppm (~0.01%wt) in children's shampoos indicate that close monitoring of raw materials and finished products is warranted. While the FDA encourages manufacturers to remove 1,4-dioxane, it is not required by federal law.
On 9 December 2019, New York passed a bill to ban the sale of cosmetics with more than 10 ppm of 1,4-dioxane as of the end of 2022. The law will also prevent the sale of household cleaning and personal care products containing more than 2 ppm of 1,4-dioxane at the end of 2022.