Ethoxylation is a chemical process in which ethylene oxide is added to fatty acids to make them more soluble in water. An example of this process is the ethoxylation of sodium dodecyl sulfate to form sodium laureth sulfate (SLES) , often used in shampoos and toothpastes as a foaming agent. The problem with Ethoxylation is its use of a petrochemical called Ethylene Oxide, which generates 1,4-Dioxane as a by-product "known to the State of California to cause cancer". Additionally, it is suspected by the Californian EPA to be a kidney toxicant, neurotoxicant and respiratory toxicant, among others.

1,4-Dioxane is commonly found in many conventional shampoos, body washes, lotions and other personal care and household cleaning products but a recent study commission by the Organic Consumers Association found this substance in many popular "natural" and "organic" brands. This same study found products certified by the USDA National Organic Program and the European BDIH foundation to be FREE of 1,4-Dioxane.

A copy of the Organic Consumer Association Consumer Alert on 1,4-Dioxane can be found here.

In a study conducted by the Campaign for Safe Cosmetics, 32 out of 48 children’s skin care products tested positive for 1,4 Dioxane at levels of 0.27 to 35 ppm.