The Dangers of 1,4-Dioxane and How to Avoid It

The Dangers of 1,4-Dioxane and How to Avoid It

In December 2019, 1,4-dioxane made headlines - the state of New York was the first US state to set limits on chemicals in household products.

But what is 1,4-dioxane, and why should the exposure be limited?



1,4-dioxane is a clear liquid that mixes very well with water. When released, it evaporates quickly; in soil, it moves easily to groundwater. When air-born, the chemical breaks down quickly, but in water it is stable and remains mostly intact. It is considered persistent in the environment, but does not bioaccumulate.

The substance is primarily used as a solvent in the manufacture of pharmaceuticals and natural health products, stabilizer for chlorinated solvents and for laboratory use. But 1,4-dioxane is also found as a trace contaminant in common household products.



Exposure to 1,4-dioxane may therefore occur through ingestion of contaminated food and water, and inhalation and/or dermal contact during the use of consumer products containing this substance. It is readily absorbed by the body through the lungs and gastrointestinal tract as well as pass through the skin.


Through release of the chemical into the environment during manufacturing or use of products containing 1,4-dioxane, traces of this chemical has been found in the groundwater and tap water at many sides throughout North America.

In fact, according to Environmental Working Group’s (EWG) Tap Water Database traces have been found in almost 2,000 water utilities throughout the United States of America, 286 of which exceed EWG’s Health Guideline of 0.35 ppb (part per billion). That means that every day, more than 8 million people in the US are using tap water that is contaminated with levels of 1,4-dioxane, which increase the risk of cancer.

1,4-dioxane and faucet

There are no national drinking water standards regarding 1,4-dioxane contamination in the US or in Canada. Several US states have introduced legal limits, and Canada has opened a public consultation, seeking comments on its draft assessment of 1,4-dioxane in drinking water that includes a proposed maximum acceptable concentration for the chemical in water. However, no national laws have been put into effect.


As a trace contaminant, 1,4-dioxane can be found in an abundance of household products. It is an impurity in all ethoxylated substances, which are used in numerous industries such as personal care products and cleaning, dishwashing and laundry detergents.

The substance is created through a process called ethoxylation, in which ethylene oxide (a known human carcinogen) is added to other chemicals to make them less harsh. An example of ethoxylation is the reaction of sodium lauryl sulfate (SLS) to sodium laureth sulfate (SLES).

1,4-dioxane is a very common contaminant in personal care products. Since it’s not an intentionally-added ingredient, you won’t see it listed on any label, but research has found the chemical in ethoxylated raw ingredients and in off-the-shelf cosmetic products. The EWG found that 97% of hair relaxers, 57% of baby soaps and 22 percent of all products in Skin Deep, their database for cosmetic products, are contaminated with 1,4-dioxane. You can read more on dangers of chemicals in the cleaning products on our blogs.

Due to health concerns linked to the chemical, the US Food and Drug Association (FDA) encourages manufacturers to remove 1,4-dioxane, but there are no national laws or requirements. The state of New York was the first in North America to limit levels of this chemical in personal care and cleaning products.




Short-term exposure to 1,4-dioxane, even at low levels, causes irritation of the eyes, nose, throat and lungs. High levels of the chemicals may also result in nausea, drowsiness and headaches.


1,4-dioxane is also associated with cancer. Animal studies show that oral exposure to the chemical causes cancer, and skin exposure can increase the cancer-causing properties of other chemicals. In the studies, exposure increased incidences of nasal cavity, liver and gall bladder tumours.

Because of these studies, the US Environmental Protection Agency (EPA), the National Toxicology Program and many other associations consider 1,4-dioxane to be a probable carcinogen to humans by all routes of exposure.


Exposure to large amounts of 1,4-dioxane has been associated with systemic effects such as liver and kidney damage. In animal studies, even short-term exposure to very high levels led to organ failure and death. Long-term exposure to contaminated water and skin contact with 1,4-dioxane also negatively affects the liver and kidneys.

1,4-dioxane has also been linked to reproductive toxicity. Animal studies suggest that prenatal exposure is toxic to the developing fetus, and California’s Proposition 65 lists it as a chemical known or suspected to cause birth defects. A study shows a link between spontaneous abortion and stillbirths and occupational exposure of people to a combination of chemicals including 1,4-dioxane, but the exact role of the chemical is unknown.

Furthermore, 1,4-dioxane is associated with cytotoxicity, which means it is toxic to cells.



While manufacturers are recommended to remove 1,4-dioxane from their products, there are no requirements. The amount of the contaminant in ethoxylated ingredients can be reduced greatly through vacuum stripping. However, this is a costly process, and it is impossible for the consumer to know if the ethoxylated ingredients used in their products has been vacuum stripped or not. Furthermore, vacuum stripping can’t remove the chemical completely; trace amounts will remain.

Manufacturers can skip ethoxylation and contamination with 1,4-dioxane entirely by using less-harsh ingredients from the start. There are many natural surfactants which are gentle yet effective, and are perfect alternatives to ethoxylated ingredients. So it’s up to us consumers to change our buying behaviour and choose products which don’t contain any ethoxylates.



1,4-dioxane is a contaminant in ethoxylated ingredients, so these should be avoided, They include:

  • Alcohol ethoxylates and ethoxylated alcohols, recognizable by the -eth ending: C12-14 Pareth-11, Ceteareth, Deceth-6, Ppg-10-laureth-7, Sodium Laureth Sulfate (SLES)
  • Alcohol alkoxylates and alkoxylated alcohols
  • Nonoxynols, also known as nonaethylene glycol or polyethylene glycol nonyl phenyl ether and other ingredients ending in -oxynol
  • Poloxamers (polyoxyethlyene, polyoxypropylene block polymers), such as Poloxamer 181
  • Polyethylene glycol (PEG), also listed as polyethylene oxide (PEO) or polyoxyethylene (POE), and compounds with these in the name, like PEG-5 cocoate

Be careful! Ethoxylated ingredients can be hidden behind non-specific ingredients - for example, SLES is often listed as ‘non-ionic surfactant’. In order to avoid 1,4-dioxane in your personal care and cleaning products, you should avoid the above ingredient groups and any non-specific ingredients.

1,4-dioxane and cleaning product


Unfortunately, since manufacturers of many household products don’t need to disclose ingredients they can put incomplete ingredient lists or lists containing non-specific ingredients onto their labels. And many green certifications are no help: EPA’s Safer Choice rates ethoxylated alcohols with a green circle, which they say shows low concern.

However, EWG rates all ethoxylated ingredients C at best, for moderate concern and potential for health hazards due to the contamination with 1,4-dioxane and ethylene oxide. EWG Verified for personal care and cleaning products allow ethoxylated ingredients only if manufacturers can provide proof that the concentration level is below 10 ppm (parts per million). They have further restricted ethoxylated ingredients to 1 ppm in 2021.

The first cleaning product to be EWG verified


If you are looking for 1,4-dioxane free products, EWG’s database can help you. AspenClean’s green cleaning products are all 100% free of ethoxylated ingredients as well as any other ingredients known or suspected to harm human health, animal wellbeing or the environment. That’s why all our products are rated A by the EWG, and why we are officially the first company to have our products EWG Verified! Try our eco friendly detergent, eco friendly dish soap too. If you are looking for a cleaning services that use EWG verified products - book it online with AspenClean. 

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