Very few, if any, cosmetics or personal care products list 1,4-dioxane as an ingredient (i), even though an analysis by Campaign for Safe Cosmetics co-founder the Environmental Working Group suggests that it may be found in 22 percent of the more than 25,000 products in the Skin Deep database of cosmetics products (ii). That's because 1,4-dioxane is a frequent contaminant of common cosmetics ingredients (iii), but as a contaminant it is not listed among intentionally added ingredients.
Products That May Contain 1,4-dioxane
Because it is a contaminant produced during manufacturing, the FDA does not require 1,4-dioxane to be listed as an ingredient on product labels. Without labeling, there is no way to know for certain how many products contain 1,4-dioxane—and no guaranteed way for consumers to avoid it.
Most commonly, 1,4-dioxane is found in products that create suds, like shampoo, liquid soap and bubble bath. Environmental Working Group's analysis suggests that 97 percent of hair relaxers, 57 percent of baby soaps and 22 percent of all products in Skin Deep may be contaminated with 1,4-dioxane (iv). Independent lab tests co-released by the Campaign for Safe Cosmetics in 2007 showed that popular brands of children's bubble bath and body wash contained 1,4-dioxane.
Besides sodium laureth sulfate, other common ingredients that may be contaminated by 1,4-dioxane include PEG compounds and chemicals that include the clauses "xynol," "ceteareth" and "oleth."
Where It Comes From
1,4-dioxane is generated through a process called ethoxylation, in which ethylene oxide, a known breast carcinogen, is added to other chemicals to make them less harsh. This process creates 1,4-dioxane. For example, sodium laurel sulfate, a chemical that is harsh on the skin, is often converted to the less-harsh chemical sodium laureth sulfate (the “eth” denotes ethoxylation), which can contaminate this ingredient with 1,4-dioxane.
Alternatives do exist, but many companies don't take advantage of them. Vacuum-stripping can remove 1,4-dioxane from an ethoxylated product, or manufacturers can skip ethoxylation entirely by using less-harsh ingredients to begin with (v). Organic standards do not allow ethoxylation at all. A study by the Organic Consumers Association (vi) shows that 1,4-dioxane is nonexistent in a variety of cosmetics produced and certified under the USDA National Organic Program, as well as other products.
Research shows that 1,4-dioxane readily penetrates the skin (vii). 1,4-dioxane is considered a probable human carcinogen by the U.S. Environmental Protection Agency (viii) and listed as an animal carcinogen by the National Toxicology Program (ix). It is included on California’s Proposition 65 list of chemicals known or suspected by the state to cause cancer or birth defects (x). The California Environmental Protection Agency also lists 1,4-dioxane as a suspected kidney toxicant, neurotoxicant and respiratory toxicant.
It is highly unlikely that any one product containing 1,4-dioxane will cause harm on its own. However, repeated exposures from many different products add up. The same baby could be exposed to 1,4-dioxane from baby shampoo, bath bubbles and body wash in a single bath, as well as from other contaminated personal care products today, tomorrow and the next day. Repeated exposures to a single carcinogen, synergistic effects from exposures to multiple carcinogenic and mutagenic ingredients, and concerns about exposures at key points in development (such as pregnancy, infancy and puberty) are cause for concern even though little risk is evident from a single small exposure.
i Malkan, S. 2008. Panic in the Organic Aisle: How a Dirty Scandle is Forcing the Natural Products Industry to Come Clean. Conscious Choice, August 2008. Available at http://seattle.consciouschoice.com/2008/08/organicpanic0808.html. Accessed August 19, 2008.
ii Environmental Working Group (2007). Impurities of Concern in Personal Care Products. Available at www.cosmeticsdatabase.com/research/impurities.php. Accessed August 19, 2008.
iii Environmental Working Group (2007). Impurities of Concern in Personal Care Products. Available at www.cosmeticsdatabase.com/research/impurities.php. Accessed July 28, 2008.
iv Environmental Working Group. 2008. EWG Research Shows 22 Percent of All Cosmetics May Be Contaminated With Cancer-Causing Impurity. Available at http://www.ewg.org/node/21286. Accessed August 19, 2008.
v Environmental Working Group (2007). Impurities of Concern in Personal Care Products. Available at www.cosmeticsdatabase.com/research/impurities.php. Accessed July 28, 2008.
vi Organic Consumers Association. Results of Testing for 1,4 Dioxane. Available at http://www.organicconsumers.org/bodycare/DioxaneResults08.cfm. Accessed August 19, 2008.
vii Spath, D.P. “1,4-Dioxane Action Level.” March 24, 1998. Memorandum from Spath, Chief of the Division of Drinking Water and Environmental Management, Department of Health Services, 601 North 7th Street, Sacramento, California 95814 to George Alexeeff, Deputy Director for Scientific Affairs, Office of Environmental Health Hazard Assessment. Viewed at: http://www.oehha.ca.gov/water/pals/pdf/PAL14DIOXAN.pdf
viii Environmental Protection Agency (2003). 1,4 Dioxane (CASRN 123-91-1). Integrated Risk Information System. Available at http://www.epa.gov/NCEA/iris/subst/0326.htm. Accessed August 19, 2008.
ix National Toxicology Program (2005). Report on Carcinogens, 11th Edition; U.S. Department of Health and Human Services, Public Health Service, National Toxicology Program, January 2005. Available at http://ntp.niehs.nih.gov/ntp/roc/eleventh/profiles/s080diox.pdf. Accessed August 19, 2008.
x Office of Environmental Health Hazard Assessment (OEHAA) (2004). State of California Environmental Protection Agency. Chemicals known to the state to cause cancer or reproductive toxicity. Available at http://oehha.ca.gov/prop65/prop65_list/files/41604list.html. Accessed August 19, 2008.