Is It Time to Quit Dry Shampoo?

These levels of benzene are worrisome. To put them into context: The U.S. Occupational Safety and Health Administration caps exposure at 0.5 ppm for those who actually work in industries where benzene is common, like oil and gas drilling, while the Food and Drug Administration (FDA) has only allowed up to 2 ppm in drug products. “However, even at low levels, chemicals can be toxic, particularly when people are exposed over long periods of time,” says Lauren Teras, PhD, a senior scientific director at the American Cancer Society.

Why is benzene in dry shampoos?

Let’s be clear: Benzene isn’t supposed to be there. “Certainly, nobody’s putting it in there on purpose or formulating it as part of a product,” says David Light, the cofounder and CEO of Valisure. While the exact method of contamination is still unclear, the experts Allure spoke with guess that it’s occurring during the manufacturing process of the propellant used in aerosol sprays.

“Propellants are the raw materials that go into the spray can and actually pressurize it, making the spray,” Light explains. “These propellants are chemicals like butane and propane — which, if they’re pure, are fine.” The problem, though, is that “they’re petroleum distillates, meaning they’re coming from the oil and gas industry, which is known for benzene contamination.”

With that in mind, it’s likely that the issue here is limited to aerosol sprays, which makes sense, seeing as some of the products in Procter & Gamble’s recall included dry conditioners, which are also packaged in aerosol cans. Plus, other aerosol-based personal-care products, such as spray-on sunscreen, antiperspirant sprays, and anti-fungal sprays, have been found to contain benzene. It’s also been found in (non-aerosol) hand sanitizer, indicating that there are other means of benzene contamination beyond aerosols — although the reasons for this are still unclear.

Another big factor here: Cosmetics are famously loosely regulated; there’s no checkpoint for impurities or contamination. After all, these dry shampoos went through formulation, manufacturing, labeling, distribution, and wholesale all without the detection of benzene, says Light. “Realizing that what goes onto our body doesn’t go through a review process from a chemical perspective is concerning.”

How worried do we need to be?

For the general public, “once you start getting between 0.8 and 1.6 ppm exposure, that is the amount that is linked [in studies] to the increased risk for leukemia and blood cancers,” says Dr. Bunick.