Consumers are becoming more knowledgeable about which ingredients to avoid in cleaning formulations. But there’s a hidden catch…toxic chemicals can exist in a product formulation without being listed on the ingredient list. Some of the most harmful toxins are trace impurities that come from essential ingredients. 1,4-dioxane is one such culprit.
What is 1,4-Dioxane?
1,4-Dioxane comes from ethoxylated surfactants, legacy formulation ingredients that are used to improve water solubility and provide a stable foam to cleaning products. However, the production of ethoxylated surfactants entails the risk of producing the toxic, hard to separate byproduct1.
While once considered an invaluable stabilizer for chlorinated solvents, specifically those used in deep cleaning of industrial machinery, 1,4-dioxane has become a particularly controversial chemical2. While not acutely toxic (LD50 = 5200 mb/kg in rats), 1,4-dioxane is an irritant and classified by numerous regulatory bodies as either a probable or known carcinogen.3,4,5
1,4-Dioxane’s true risk lies in the fact that it is a forever chemical. The diether structure of 1,4-dioxane gives the chemical remarkably high stability in water. Further, 1,4-dioxane does not bind to minerals or soil and resists most forms of biodegradation, making it spread rapidly and accumulate in groundwater like other forever chemicals such as polyfluoroalkyl substances.2,6,7 Detectable 1,4-dioxane has been found in an alarming number of utility-supplied tap water locations in the U.S.2
Consumer products have never used 1,4-dioxane as an ingredient. However, due to the high usage levels of associated ethoxylated surfactants, the U.S. FDA has tested these products and their ingredients for the chemical since 1979. These tests have shown levels up to 279 parts per million (ppm) for on-the-shelf consumer products.8 Testing in 2019 showed levels of 1,4-dioxane as high as 17 ppm in on-the-shelf consumer products.9
If 1,4-dioxane is a known impurity of ethoxylated surfactants, why is it not removed during their production process? Unfortunately, 1,4-dioxane has low volatility and is unable to be extracted from most ethoxylated surfactants. The principle 1,4-dioxane removal systems that have been developed are time and energy intensive.10,11 Due to this, not all manufacturers completely strip their ethoxylated surfactants from 1,4-dioxane.9 When 1,4-dioxane is not removed, it accompanies the ethoxylated surfactant into the finished formula1.
High–foaming surfactants are essential performance ingredients for household and I&I cleaning products, but even trace 1,4-dioxane from these materials can make its way to groundwater and contaminate water supplies for years. What options do formulators have for maintaining the performance of their products while avoiding 1,4-dioxane?
Creating 1,4-Dioxane-Free Formulations
Luckily, there’s a solution. Formulators are beginning to look at replacing ethoxylated surfactants with customized sophorolipids—biosurfactants in the glycolipid class that are specifically designed to have better performance and sustainability. One example is the recently launched Amphi® line of biosurfactants by Locus Performance Ingredients. The Amphi® sophorolipids are naturally derived, non-GMO, have remarkably low usage rates and none of the irritation or toxic byproducts of petrochemical surfactants. The Amphi® ingredient line features a range of HLB and foaming characteristics, providing formulators with the flexibility needed for formulation optimization.
Coming up, we’ll discuss the new regulatory actions pushing formulators to innovate with new biosurfactant solutions that eliminate 1,4-dioxane from consumer and industrial products, and more details on how these solutions are superior to surfactants.
For general surfactant information, download our report.
1Stanton, Kathleen. 2019. “1,4-Dioxane Formation, Control, and Occurence in Cleaning Products.” American Cleaning Institute. August 21. Accessed November 17, 2020.
2Hogue, Cheryl. 2020. 1,4-Dioxane: Another forever chemical plagues drinking-water utilities. November 8. Accessed November 17, 2020. https://cen.acs.org/environment/pollution/14-Dioxane-Another-forever-chemical/98/i43.
3U.S. Department of Health and Human Services . 2011. 12th Report on Carcinogens (RoC). June 10. Accessed November 17, 2020. https://web.archive.org/web/20140714132609/http:/ntp.niehs.nih.gov/pubhealth/roc/roc12/index.html.
4U.S. Environmental Protection Agency. 2000. 1,4-Dioxane (1,4-Diethyleneoxide). January. Accessed November 17, 2020. https://www.epa.gov/sites/production/files/2016-09/documents/1-4-dioxane.pdf.
5California Environmental Protection Agency. 2010. Chemicals Known to the State to Cause Cancer or Reproductive Toxicity. April 2. Accessed November 17, 2020. https://web.archive.org/web/20100524160032/http:/www.oehha.org/prop65/prop65_list/files/P65single040210.pdf.
6American Chemical Society. 2020. The persistent problem of 1,4-dioxane in water. November 11. Accessed November 17, 2020. https://phys.org/news/2020-11-persistent-problem-dioxane.html.
7Miller, K. 2019. What are PFAS, the “Forever Chemicals” the FDA Found in Our Food Supply? June 4. Accessed November 19, 2020. https://www.prevention.com/health/a27720891/what-are-pfas-chemicals-food-supply-fda/#:~:text=1%20The%20Food%20and%20Drug%20Administration%20has%20confirmed,be%20dangerous%2C%20and%20how%20to%20potentially%20avoid%20them.
8Black, R. E., F. J. Hurley, and D. C. Havery. 2001. “Occurence of 1,4-Dioxane in Cosmetic Raw Materials and Finished Cosmetic Products.” Journal of AOAC International 666-670.
9Citizens Campaign for the Environment. 2019. “Shopping Safe: The 2019 Consumer Shopping Guide. Protecting Your Household From 1,4-Dioxane Exposure.” Citizens Campaign for the Environment. Accessed November 17, 2020.
10Mohr, T. K. G. 2019. “1,4-Dioxane Removal from Personal Care Products – Opportunities, Benefits, and Costs.” California Department of Toxic Substances Control. August 31. Accessed November 17, 2020. https://dtsc.ca.gov/wp-content/uploads/sites/31/2019/08/Tom-Mohr_14DX_Removal_PCPs_Opportunities.pdf.
11Chemithon. 2013. DRS Dioxane Removal System . Accessed November 17, 2020. http://chemithon.com/Proc_drs.html.