ethoxylation process, when ethylene oxide is added to fatty acid alcohols to give them detergent properties, to turn them into surfactants, like SLeS, our PEG esters, and things like ceteareth-20 - is that they contain 1,4 dioxane. A report put out by the Campaign for Safe Cosmetics, "Toxic Tub", notes this ingredient can be found in many children's products, and can be found in loads of other products that contain ethoxylated ingredients.
So what is 1,4 dioxane (or diethylene oxide)? From the Agency for Toxic Substances and Disease Registry (click here for the full PDF):
1,4-Dioxane is a clear liquid that easily dissolves in water. It is used primarily as a solvent in the manufacture of chemicals and as a laboratory reagent; 1,4-dioxane also has various other uses that take advantage of its solvent properties.1,4-Dioxane is a trace contaminant of some chemicals used in cosmetics, detergents, and shampoos. However, manufacturers now reduce 1,4-dioxane from these chemicals to low levels before these chemicals are made into products used in the home.
International Agency on Cancer considers it a group 2B carcinogen, which is defined as "The agent (mixture) is possibly carcinogenic to humans. The exposure circumstance entails exposures that are possibly carcinogenic to humans." It can also cause liver and kidney damage. This is one nasty chemical!
The FDA position on 1,4 dioxane can be found here, but I'll summarize it a little...The FDA doesn't have a limit for 1,4 dioxane and they are recommending manufacturers minimize the amount of 1,4 dioxane in products by vacuum stripping the ingredients after ethoxylation. Health Canada makes the same recommendations.
The limits are 10 ppm for polysorbates in our food, glycerides and triglycerides in supplements, and in a spermicide in a once popular contraceptive sponge. There aren't any cosmetic limits.
1,4 dioxane has no place in our products, and responsible manufacturers will go through the vacuum stripping process to ensure our safety. The amounts of 1,4 dioxane are incredibly low in most of the products tested in the Toxic Tub report, and very few products reach 10 ppm.
One of the things that really bothered me about the Toxic Tub report is this - "Some products tested for this report did not contain formaldehyde or 1,4-dioxane. However, that does not mean the products are safe." What does this mean? If you say these things are bad for us and you don't find them in the product, then shouldn't we breathe a sigh of relief? No. Because there might be other ingredients we should fear in the products. (Sorry, a bit of my opinion there, but I really do feel this last sentence of their report is fear-mongering.)
So how worried should we be about using ethoxylated ingredients?
From Choose Organics:
Skin absorption studies demonstrated that dioxane readily penetrates animal and human skin during use of contaminated shampoos and other personal care products, although it is uncertain how much is available for absorption and how much evaporates instead of penetrating the skin.
From the Suzuki Foundation Report:
Depending on manufacturing processes, PEGs may be contaminated with measurable amounts of 1,4- dioxane...1,4-dioxane can be removed from cosmetics during the manufacturing process by vacuum stripping, but there is no easy way for consumers to know whether products containing PEGs have undergone this process. In a study of personal care products marketed as “natural” or “organic” (uncertified), U.S. researchers found 1,4-dioxane as a contaminant in 46 of 100 products analyzed.
(This study of personal care products refers to this report from the Organic Consumers' Association. Unfortunately, the full report is "file not found" when I clicked on it, so I can't tell you at what levels the 1,4 dioxane was found, only the product lines that might have it.)
From the FDA:
As a precaution, FDA followed up with skin absorption studies, which showed that 1,4-dioxane can penetrate animal and human skin when applied in certain preparations, such as lotions. However, further research by FDA determined that 1,4-dioxane evaporates readily, further diminishing the already small amount available for skin absorption, even in products that remain on the skin for hours. (Robert L. Bronaugh, "Percutaneous Absorption of Cosmetic Ingredients," in Principles of Cosmetics for the Dermatologist, Philip Frost, M.D., and Steven Horwitz, M.D., Eds. St. Louis: The C.V. Mosby Company, 1982)
From Health Canada:
Dioxane exposure via cosmetic products was evaluated in Canada’s Chemical Management Plan (CMP) and found to be safe. Health Canada advises industry to follow the recommendations set out by the U.S. FDA. If a product was found to have unacceptable levels of this impurity, Health Canada would take action to remove the product from sale.
We have two facts here. The ethoxylation process can produce 1,4 dioxane. And 1,4 dioxane is considered carcinogenic. But they don't necessarily connect to make an argument against ethoxylated ingredients.
How much 1,4 dioxane is significant? If the limits are 10 ppm for food products, are results like 6 ppm or 0.65 ppm in an entire bottle of product significant? If 1,4 dioxane evaporates readily on our skin, how much of the 0.65 ppm is really penetrating our skin and is that significant?
I don't know the answers to these questions, but it seems like no one else does either. But now you know a little more about why ethoxylated ingredients are on the much maligned list.