1,4-Dioxane and Laundry Soap: Free and Gentle or a Marketing Free-for-All?

Two Tide products had 1,4-dioxane concentrations at the high end of what was typical in the 1990s -- levels that were supposedly a thing of the past. (Note: There are likely more products than these containing the chemical; the study only looked at 20 products.)
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More than 80,000 chemicals are produced, used, and present in the United States. This is one of their stories.

"Free of dyes and perfumes" on the label doesn't mean "free of carcinogens."

Independent Testing Reveals Undisclosed Ingredients

Recently The New York Times' Green blog raised the spotlight on a report released last November on toxic chemicals found in 20 popular cleaning products. Women's Voices for the Earth, a national environmental group based in Missoula, Mont., had commissioned independent tests on all-purpose cleaners, laundry detergents, dryer sheets, air fresheners, disinfectant sprays, and furniture polish made by Clorox, Procter & Gamble, Reckitt Benckiser, SC Johnson, and Sunshine Makers. The testing revealed that a number of the products had chemicals that are known to be allergens or are linked to reproductive and endocrine disruption... and cancer.

I have to say the findings do not come as a huge surprise. Previous work (see here and here) has documented the ubiquity of toxic chemicals in everyday consumer products. It's not even that surprising that some of these compounds are absent from product labels. What may be surprising is that the language used to market some of these toxic-containing products suggests that they would be anything but toxic-containing.

Today's post focuses on one such example: the presence of 1,4-dioxane in laundry detergent. Should you be concerned about this? You'll have to decide.

1,4-Dioxane: What It Is and Why It Matters

The chemical in question, whose toxicological profile is provided in a 2007 draft in the federal Agency for Toxic Substances and Disease Registry, "is a clear liquid with a faint pleasant odor [that] mixes easily with water." A synthetic industrial chemical, 1,4-dioxane has many uses as a solvent and a stabilizer in manufacturing, especially in the making of chemicals, plastics, pesticides, food additives, and pharmaceuticals. It's also a contaminant produced in the manufacture of surfactants used in cosmetics, detergents, and shampoos.

Laboratory studies (see here) have established that chronic exposure to 1,4-dioxane can cause cancer in mice and rats, but there is as yet no specific evidence establishing a causal relationship between 1,4-dioxane and cancer in humans. As a result, the Environmental Protection Agency lists it as "likely to be carcinogenic to humans." The U.S. Department of Health and Human Services concurs: "1,4-dioxane is reasonably anticipated to be a human carcinogen."

In really high doses, 1,4-dioxane can be really bad news. According to the Health and Human Services agency, current data "are sufficient to clearly identify the liver and kidneys as the target organs for 1,4-dioxane toxicity following short-term exposure to relatively high amounts" of it via ingestion, inhalation, or absorption through the skin. Acute exposure to excessive but undetermined concentrations in the workplace has resulted in death.

Are We Exposed to the Stuff?

The good news is that unless you work in or live very close to a plant where 1,4-dioxane is produced, it is highly unlikely that you will ever be exposed to levels sufficient to cause acute distress.

But what about lower levels of exposure -- not enough to kill you right away, but perhaps enough to eventually cause cancer? On that front the news is not that encouraging. Because, If you live in the United States and eat and breathe, you are probably exposed to it.

1,4-dioxane has been observed in ambient air with generally higher concentrations indoors than outdoors (see this 1986 study). The Health and Human Services Department reports that "tap water can contain 1,4-dioxane, so you also can be exposed to 1,4-dioxane during activities such as showering, bathing, and laundering," and that "drinking water containing 1,4-dioxane" is one of the "primary routes of human exposure." It may also come to us through our food -- as residues on pesticide-treated crops (such as vine ripened tomatoes), in manufactured additives, and on some packaging materials. The Centers for Disease Control puts it succinctly: "people are exposed to 1,4-dioxane every day because of its widespread use in medicines, shampoo, cosmetics, detergents, and household items."

Government Regulations Not to the Rescue

So we're all exposed to some 1,4-dioxane. Is it enough to make us sick? I don't think anyone knows for sure. But all those exposures from air, water, and food can accumulate. It almost surely is not good for you. So surely the federal government, with its job-killing, power-grabbing, regulation-crazed agencies like the EPA and Food and Drug Administration, has stepped in and banned the stuff, right? Actually, not very much at all.

There are no federal regulations on 1,4-dioxane for drinking water. There are no federal regulations for ambient air concentrations (although there are workplace regulations in effect for ambient and dermal exposure). There is an FDA-imposed, 10-parts-per-million limit in food and drugs.

And there are no federal limits for 1,4-dioxane in consumer products. Claims by the Health and Human Services agency and others that the FDA has placed a limit in cosmetics have been denied by none other than the FDA.

So the feds may not be on the case, but the Golden State is, sort of. California's Proposition 65 establishes a safe daily exposure of 30 micrograms (max) as part of its Safe Drinking Water and Toxic Enforcement Act. To avoid triggering the law's labeling requirement, in at least one instance the state set a limit on 1,4-dioxane of 10 parts per million for dish soap.

What's the Story With Consumer Products?

The apparent reason that the federal government is silent on 1,4-dioxane in most consumer products is its view that the process of "vacuum stripping" has rendered it a non-issue: "Manufacturers now reduce 1,4-dioxane from these chemicals to low levels before these chemicals are made into products used in the home." A 2005 report by the Department of Health and Human Services states:

[B]etween ... 1992 and 1997, the average concentration of 1,4-dioxane in cosmetic finished products was reported to fluctuate from 14 to 79 [parts per million]. ... Current levels of 1,4-dioxane in consumer products are much lower since that time because manufacturers are once again taking action to remove much of the 1,4-dioxane.

This conclusion, that 1,4-dioxane was once a concern but is no longer, is proliferated on the Web -- from blogs (see here and here) to other federal groups (such as the EPA and the military). Is it really no longer a concern?

Enter Women's Voices for the Earth

Among the undisclosed ingredients that the recent study by the Missoula-based group turned up was 1,4-dioxane in four products:

  • Tide Original Scent Liquid Laundry Detergent at 63 parts per million

  • Tide Free & Gentle Liquid Laundry Detergent at 89 parts per million
  • Simple Green Naturals Multi-Surface Care at 0.45 parts per million
  • Bounce Free & Sensitive Dryer Sheets at 0.32 parts per million
  • That's right, two Tide products, made by Procter and Gamble, had 1,4-dioxane concentrations at the high end of what was typical in the 1990s -- levels that were supposedly a thing of the past. (Note: There are likely more products than these containing the chemical; the study only looked at 20 products.)

    Now, before running into the laundry and dumping that bottle of Tide, you might reflect a bit. Since you don't actually put laundry detergent on your skin, and because 1,4-dioxane is miscible in water, just because the chemical is in your detergent does not mean you end being exposed to much.

    But even so, you might reasonably conclude that you'd rather not mess with the stuff at all. And if that's your preference, remember that reading the label to check whether your detergent contains 1,4-dioxane won't help -- because it's a byproduct, it's generally not listed. And here's the real drag -- you read "Free and Gentle" on the bottle and you might well think that bottle is not just "free of dyes and perfumes" but also free of carcinogens, especially carcinogens that the manufacturer knows are there and and that it can readily remove. Alas, as they say, you can't know a consumer product by its hype.

    This piece is cross-posted with TheGreenGrok.

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