When it comes to ethoxylated emulsifiers and 1,4-Dioxane, Ricardo Diez, PhD, gives non-government organizations an F. In a presentation during the At-Home-Live webinar series produced by the New York Chapter of the Society of Cosmetic Chemists, Diez said this workhorse chemistry is misunderstood and bad actors’ misinformation only adds to the confusion.

“The real issue with 1,4-Dioxane is its presence in drinking water—no argument, there,” explained Diez. “But this should not be equated with the risk of having it in consumer products at the current levels of 1,4 D.”
 
Diez is a cosmetic industry veteran who worked for suppliers and marketers for 40 years prior to retiring. He teaches the next generation of cosmetic chemists as an instructor in Rutgers University’s Masters in Business and Science program. 
 
“In the specifics of ethoxylated emulsifiers, their 1,4 D content, if properly manufactured, should be less than 1ppm, thus resulting in about 30ppb in finished products, most of which will never penetrate the skin due to evaporation,” he explained. “Of course, there is no impact from leave-on products to 1,4 D in drinking water.”
 
 
The Benefits of Ethoxylated Emulsifiers
 
Diez’s defense of ethoxylated emulsifiers is due to the fact that they provide a host of benefits in finished formulations. For example, ethoxylated emulsifiers, unlike the ones suggested as replacements, are not discrete but oligomeric materials. The oligomers “adjust themselves” while making an emulsion to give the best possible product, according to Diez.
 
Ethoxylated emulsifiers also have reverse solubility in water with respect to temperature. According to Diez, this is the “magic” behind the Phase Inversion Temperature (PIT) method for making emulsions that yields very stable creams and lotions. 
 
“This can be measured with the old Cloud Point method, but nowadays, the Cloud Point number does not even appear in the specifications,” he explained.
 
Finally, ethoxylated emulsifiers are excellent to control the gel network which are key to sensorial profile and stability and active delivery.
 
 
A Novel Solution
 
Yet, no matter how good the defense, Diez doesn’t expect Campaign for Safe Cosmetics (CSC) and other NGOs will ever join “the dose makes the poison” camp when it comes to ethoxylates.
In the webinar, he showed how CSC quoted a 1987 paper as reference for the ‘lowest part per billions” dose of 1,4-D that gave cancer to the animals—but the paper clearly shows that the dose was in the 0.05% range.
 
“The funny part is that anyone that checks the paper can see that they are misquoting the paper,” explained Diez. “Researchers must check references used by organizations to ascertain if they have been quoted properly.”
 

Rather than try to convince the naysayers and misinformed, Diez suggested a novel solution—petition the US Food and Drug Administration to regulate 1,4 D. Such an unorthodox move, he explained, will help to clarify the safety of cosmetics formulated with materials with “eth” or “PEG” in them. Diez said that FDA’s current statement on the subject, “If the FDA were to determine that a health hazard exists, it would advise the industry and the public,” is “diluted,” in his words.
 
Rather, he suggested a different regulation for different products. For leave-on prepared with the typical 3-5% emulsifier containing less than 1ppm 1,4 D (as some suppliers do), a regulation of 1ppm max in the final product will be well above the actual amount in the product, according to Diez.
 
It could be different for rinse-off products since the impact of 1,4 D here is related to the discharge into the environment/drinking water than to the safety of the product itself during usage.
 
“But as I said in the webinar, I do not know how much of the 1,4 D in drinking water comes from cosmetics vs other consumer products and the industrial uses of 1,4 D—and we should know,” explained Diez. “But I am 100% behind an FDA regulation. In fact, I think the FDA should regulate the whole cosmetic industry. That will clean it very well.”