Ethoxylated IngredientsUpdated a month ago

Ethoxylated Ingredients are a group of ingredients made by the process of ethoxylation in which carcinogenic ethylene oxide is reacted with other ingredients to make them less harsh on the skin. As a result of the ethoxylation process, 1,4-dioxane is created and can be left behind in the product. 1,4-dioxane can be reduced or removed from a product through the vacuum-stripping process. But independent tests show that many manufacturers fail to do so. The U.S. Environmental Protection Agency (“EPA”) has classified 1,4-dioxane as “likely to be carcinogenic to humans.” United States Food and Drug Administration (“FDA”) studies showed that 1,4-dioxane can penetrate human skin. 

Sources: 

https://www.fda.gov/Cosmetics/ProductsIngredients/PotentialContaminants/ucm101566.htm
http://www.safecosmetics.org/get-the-facts/chemicals-of-concern/14-dioxane/
https://www.atsdr.cdc.gov/phs/phs.asp?id=953&tid=199
https://www.organicconsumers.org/press/ocas-new-study-finds-greatly-reduced-carcinogens-personal-care-products