What kind of bubble bath should we buy?

Driving home on late Saturday/early Sunday, listening to NPR’s “Living on Earth” program, I heard a story about the chemical dioxane (or more fully, 1,4-dioxane) being found in children’s shampoos and bubble baths as a byproduct of the manufacturing process. Dioxane is banned in Europe as a carcinogen. The FDA limit is 0.5 parts per million. Several products (including some which the program alleged were being recalled) contained much higher concentrations. The part that made me take notice was the Hello Kitty Bubble Bath, with 12 ppm, the highest of any of the children’s products tested. One guess which bubble bath we buy for Sammy. In the car, I was horrified. The thought of Sammy developing cancer because of a bubble bath.

Reading LOE’s online version of their story, the press release that led to the story, the lab results, and a cancer blog entry that covered the story, my thinking has changed a bit. The story certainly brings up valid points, and it’s important to know the F.D.A. doesn’t test health and beauty products, including children’s shampoos, soaps and bath products. And honestly, it’s terrible that the maker of the shampoo is spending a huge amount on licensing Hello Kitty but wouldn’t spend a relatively small amount to remove dioxane from its product. If they’ve actually recalled it (which I couldn’t prove) then maybe there’s something going on here. But realistically, I suspect that 12 parts per million of this particular chemical are probably not worth worrying about, especially after diluted in the bath. On the other hand, who wants to voluntarily expose their child to a carcinogen?

I’m not a chemist. After a few hours of research, I became frustrated. I didn’t see any balanced web sites that honestly assessed the safety of children’s products without bias from a manufacturer. The test results are very specific: These five products had this much dioxane. But ok, what bubble bath is safe and I should buy instead? Where’s the invisible hand when you need it? Is this the F.D.A.’s job or isn’t it?

One Response to “What kind of bubble bath should we buy?”

  1. Robert Goodman Says:

    Here it is 14.5 years later and I’m sure it’s not uppermost in your mind, but who knows who might read this now, so here goes, because I’m a biochemist.

    The overall story is that as research goes on, we’re finding more and more, and weaker and weaker, carcinogens. The strong ones were all discovered long ago, so now we’re looking for subtler and subtler (and less likely) effects. 1,4-dioxane (although it’s also been used as a solvent — I used it 50 years ago in our college laboratory in extracting cholesterol from gallstones) is chiefly a byproduct of the use of ethylene oxide, a gas (prepared from natural gas) with a great number of uses. It’s used to sterilize medical equipment and to synthesize a variety of materials, from polyethylene glycol (as in hydraulic fluid, such as brake fluid) to ethoxylated surfactants. It’s the latter class of products where it’s come to your attention.

    1,4-dioxane (and to a lesser extent, 1,3-dioxane as well as larger heterocyclic ring molecules) contaminates, to a lesser or greater degree, everything made from ethylene oxide, i.e. everything that’s ethoxylated. For most of our history of use of these products, nothing much was thought of this contamination. Ethoxylation was used to produce the surface-active agents in sudsless detergents like the original All and Lestoil. But later it was learned that for the very sudsy surfactants as used in bubble baths, ethoxylated versions could be produced that were nearly as, or even more, sudsy, but a lot milder to skin and eyes. So ethoxylation made possible no-sting baby shampoo.

    Hence the dilemma that comes up now. We don’t know any safe level for probable human carcinogens like 1,4-dioxane because their effect is so weak and hard to detect to begin with that we can’t measure where it ends entirely. But if we give up ethoxylation entirely, we wind up with ingredients that are harsher to skin and eyes. We can remove dioxane after ethoxylation — costs money, and no valuable byproduct is generated by this step — but not entirely.

    I wouldn’t be concerned about dioxane exposure via bubble baths, because we’re getting it in our dishwashing liquids. Also our laundry detergents, stuff made with polyethylene glycol, etc. My own bubble bath formula (see Web site while it’s still up there — I expect to leave BestWeb soon) contained an ethoxylate.

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