You won’t find 1,4-dioxane on any ingredient label. It’s never added to products intentionally. And yet it shows up in an estimated 46% of personal care products tested by the Environmental Working Group, including baby shampoos, bubble baths, body washes, and laundry detergents marketed as “gentle” or “natural.” It’s also one of the most persistent contaminants in U.S. drinking water.

This is a chemical that exists because of how other chemicals are manufactured. NonToxicLab tracks contaminants like 1,4-dioxane that fly under the regulatory radar, and understanding how this one gets into your products is one of the more practical things you can do to reduce your family’s chemical exposure.

How 1,4-Dioxane Ends Up in Your Products

1,4-dioxane (not to be confused with “dioxin” or “dioxins,” which are different chemicals entirely) is a synthetic industrial chemical classified as a probable human carcinogen by the EPA and the International Agency for Research on Cancer (IARC).

It gets into consumer products as a byproduct of a manufacturing process called ethoxylation. Ethoxylation is used to make harsh ingredients milder. Manufacturers take a chemical like sodium lauryl sulfate (SLS), which is an effective but irritating surfactant, and treat it with ethylene oxide to produce sodium laureth sulfate (SLES), which foams just as well but is gentler on skin.

The problem is that ethylene oxide processing leaves behind traces of 1,4-dioxane. The contamination is well-known in the industry. It can be removed through a process called vacuum stripping, which is effective and not particularly expensive. But vacuum stripping is voluntary. No federal regulation requires manufacturers to remove 1,4-dioxane from finished products, and no federal regulation sets limits on how much can be present.

So some companies strip it. Others don’t bother.

Where You’ll Find It

Personal Care Products

Any product containing ethoxylated ingredients may carry 1,4-dioxane contamination. The most common ethoxylated ingredients to watch for:

  • Sodium laureth sulfate (SLES) in shampoo, body wash, bubble bath, and face wash
  • PEG compounds (polyethylene glycol) in creams, lotions, and cosmetics
  • Polysorbates (polysorbate 20, polysorbate 80) in lotions and food products
  • Ceteareth and oleth compounds in hair conditioners and moisturizers
  • Any ingredient with the letters “-eth-” or the prefix “PEG-” in its name

A rule of thumb: if the ingredient list contains words ending in “-eth” (like laureth, ceteareth, oleth) or starting with “PEG-” followed by a number, the product may contain 1,4-dioxane.

Products labeled “for sensitive skin” or “baby-gentle” are not exempt. Some of the highest levels of 1,4-dioxane have been detected in baby wash products, because SLES is one of the most popular surfactants in gentle formulations.

Our non-toxic baby shampoo guide and non-toxic shampoo guide cover products that avoid ethoxylated surfactants entirely.

Laundry Detergent

Laundry detergents rely heavily on ethoxylated surfactants. Tests by consumer advocacy groups have found measurable levels of 1,4-dioxane in popular conventional brands. The contamination ends up on your clothes and bed sheets through residue left after washing. Our guide to non-toxic laundry detergent highlights brands that have been tested for this contaminant.

Dish Soap

Similar to laundry detergent, conventional dish soaps frequently contain SLES and other ethoxylated surfactants. If you’re washing dishes by hand, you’re getting direct skin contact. Our non-toxic dish soap guide covers options without ethoxylated ingredients.

Drinking Water

1,4-dioxane has become one of the most widespread drinking water contaminants in the United States. It enters water supplies through industrial discharge and improper disposal. According to the EPA’s Unregulated Contaminant Monitoring Rule data, 1,4-dioxane was detected in about 21% of public water systems tested.

The problem with 1,4-dioxane in water is that it’s extremely difficult to remove. It’s miscible with water (it mixes completely), resistant to biodegradation, and not effectively removed by standard granular activated carbon filtration. Advanced treatment methods like UV oxidation or advanced oxidation processes are needed, and many water treatment facilities don’t have that technology.

For home filtration, reverse osmosis systems are the most accessible option that addresses 1,4-dioxane. Standard carbon pitcher filters do very little against it. Our water filtration guide explains which systems can actually reduce this contaminant.

Health Effects

Cancer Risk

The EPA classifies 1,4-dioxane as a “likely human carcinogen.” IARC classifies it as a Group 2B carcinogen (possibly carcinogenic to humans). The evidence comes primarily from animal studies showing increased liver cancer and nasal tumors in rodents exposed to 1,4-dioxane through drinking water.

The distinction between “likely” and “possibly” carcinogenic reflects differences in how the EPA and IARC weigh evidence, not a fundamental disagreement about whether the chemical is concerning. Both agencies consider it a cancer risk.

Dr. Peter Attia has discussed on his podcast how cumulative chemical exposures contribute to overall disease risk, noting that individual chemicals may seem low-risk in isolation but that the aggregate picture matters. 1,4-dioxane is a good example of that principle. No single shampoo bottle poses a dramatic cancer risk. But daily exposure across multiple product categories, combined with contaminated drinking water, adds up.

Organ Toxicity

Beyond cancer, 1,4-dioxane is toxic to the liver and kidneys. High-dose animal studies show clear damage to both organs. At the lower doses relevant to consumer exposure, the effects are less dramatic but still documented. The liver processes 1,4-dioxane into a metabolite called beta-hydroxyethoxyacetic acid, which is excreted in urine. Chronic low-level exposure means the liver is continuously working to metabolize this chemical.

Skin Absorption

1,4-dioxane penetrates skin readily. A study published in the Journal of Applied Toxicology found that 1,4-dioxane in personal care products is absorbed through the skin and detectable in blood. This matters because skin absorption bypasses the digestive system’s first-pass metabolism, meaning the chemical enters circulation more directly.

Dr. Shanna Swan, whose research on endocrine-disrupting chemicals in consumer products has been widely cited, writes that the skin absorption pathway for chemicals in personal care products is consistently underestimated in risk assessments. Products that sit on skin (lotions, creams) pose a different exposure profile than products that are rinsed off (shampoo, body wash), but both contribute to total body burden.

The Regulatory Failure

1,4-dioxane in personal care products sits in a regulatory blind spot.

The FDA does not set limits for 1,4-dioxane in cosmetics or personal care products. The agency has acknowledged the contamination issue and has said that manufacturers should remove it, but compliance is voluntary. There is no testing requirement and no enforcement mechanism.

At the federal level, there is no maximum contaminant level (MCL) for 1,4-dioxane in drinking water, though the EPA has listed it on the Contaminant Candidate List. Some states have taken independent action. New York passed a law in 2019 setting limits on 1,4-dioxane in personal care products and household cleaning products (1 ppm by the end of 2023), becoming the first state to do so.

This patchwork approach means your protection depends on where you live and which brands you buy. The TSCA (Toxic Substances Control Act) has similar gaps that leave many chemicals inadequately regulated.

How to Reduce Your Exposure

Read Ingredient Labels Differently

Since 1,4-dioxane isn’t listed as an ingredient, you need to look for the precursor ingredients that signal its likely presence:

  1. Avoid SLES (sodium laureth sulfate) when possible. SLS (sodium lauryl sulfate) is a different chemical and is not ethoxylated, so it doesn’t carry 1,4-dioxane contamination. SLS has its own drawbacks (it’s a skin irritant), but 1,4-dioxane isn’t one of them.
  2. Watch for PEG compounds. PEG-8, PEG-100, PEG-anything. All are ethoxylated.
  3. Check for “-eth” ingredients. Ceteareth, laureth, oleth, steareth. The “-eth” suffix indicates ethoxylation.
  4. Look for polysorbates. Polysorbate 20 and polysorbate 80 are ethoxylated.

Choose Certified Products

Products with the USDA Organic seal for body care, the EWG Verified mark, or the MADE SAFE certification are less likely to contain 1,4-dioxane because those certifications either restrict ethoxylated ingredients or require testing for this contaminant.

Filter Your Drinking Water

If your local water supply contains 1,4-dioxane (you can check by looking at your municipality’s Consumer Confidence Report or searching the EWG Tap Water Database), reverse osmosis filtration is your most practical defense at home. Our best gravity water filters guide includes options with RO capability.

Prioritize Products That Contact Skin Longest

Focus your product swaps on items that stay on your skin: body lotion, moisturizer, sunscreen, and leave-in hair products. These contribute more to absorption than rinse-off products like shampoo, though both matter. Our guides to non-toxic body lotion and non-toxic face moisturizer list products free from ethoxylated ingredients.

What People Ask

Is 1,4-dioxane the same as dioxin?

No. Despite the similar names, they are completely different chemicals. Dioxins are a group of highly toxic chlorinated compounds (like TCDD) produced as byproducts of industrial processes and incineration. 1,4-dioxane is a cyclic ether used as an industrial solvent and found as a contaminant in consumer products. The confusion is understandable but important to clear up.

Why doesn’t the FDA ban 1,4-dioxane in personal care products?

The FDA’s authority over cosmetics and personal care products is limited. Unlike drugs, cosmetics don’t require pre-market approval. The FDA can recommend that manufacturers remove contaminants, but it has limited power to enforce those recommendations. This regulatory gap is one of the reasons we wrote about the FDA’s cosmetics regulation problem.

Can I wash 1,4-dioxane out of products?

No. 1,4-dioxane is a contaminant within the product formula, not something sitting on top that can be rinsed away. The only way to avoid it is to choose products made without ethoxylated ingredients.

Do “natural” or “organic” products contain 1,4-dioxane?

They can, if they contain ethoxylated ingredients. The words “natural” and “organic” on personal care products are not well-regulated (except for the USDA Organic seal, which has strict standards). A product labeled “natural” can absolutely contain SLES and carry 1,4-dioxane contamination.

How much 1,4-dioxane is in my water?

Check your water utility’s annual Consumer Confidence Report or search the EWG Tap Water Database by zip code. If your utility has tested for 1,4-dioxane, the results will be listed there. Keep in mind that many smaller water systems have not tested for this contaminant.

Does boiling water remove 1,4-dioxane?

No. Boiling can actually concentrate 1,4-dioxane because the water evaporates while the contaminant remains. Reverse osmosis is the most practical home treatment method. Standard carbon filters (like Brita pitchers) provide minimal reduction of 1,4-dioxane.

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