High levels of cancer-causing chemical detected in dry shampoo, study finds

A recent study has found high levels of benzene, a chemical known to cause cancer in humans, in several dry shampoo products still available in stores.

The study, which was conducted by Connecticut-based independent laboratory Valisure, comes just one week after Unilever recalled 19 dry shampoo aerosol products for “potentially elevated levels” of benzene.

On 1 November, Valisure sent a citizen petition to the US Food and Drug Administration after it found levels of benzene in 70 per cent of samples tested in the study. Among 148 batches from 34 different brands of dry shampoo products, 70 per cent of samples tested showed “quantifiable” levels of benzene.

According to the Center for Disease Control and Prevention, benzene is a chemical that can occur naturally in the environment  – such as in crude oil or gasoline – and can be used to manufacture plastics, lubricants, dyes and detergents. Indoor and outdoor air also contains low levels of benzene due to tobacco smoke, motor vehicle exhaust, industrial emissions and or household paints.

The major effect of long-term exposure to benzene is on the blood, which can lead to a decrease in red blood cells – or anemia – after a year or more of exposure to high benzene levels. The Department of Health and Human Services (DHHS) has determined that benzene can also cause blood-related cancers, such as leukemia.

“The detection of high levels of benzene in dry shampoos should be cause for significant concern since these products are likely used indoors, where benzene may linger and be inhaled for prolonged periods of time,” said David Light, Chief Executive Officer of Valisure, in a statement.

“These and other issues identified by Valisure, including the detection of benzene in body spray, hand sanitizer, and sunscreen products, strongly underscore the importance of independent testing and its need to be better integrated into an increasingly complex and vulnerable global supply chain.”

On 25 October, Unilever United States announced a recall of 19 dry shampoo aerosol products produced prior to October 2021, according to a statement published by the US Food and Drug Administration. These include dry shampoos from the brands Dove, Suave, and TRESemmé.

A full list of recalled products can be found here.

After conducting an internal investigation, the company identified the propellant used in its aerosol cans as the source for the high levels of benzene. “Unilever has worked with its propellant suppliers to address this issue,” the company said, adding that US retailers have been notified to remove the 19 recalled products from their shelves.

However, Unilever said that an independent health hazard evaluation found that daily exposure to the benzene in its recalled dry shampoo products “would not be expected to cause adverse health consequences.”

The FDA has identified steps for consumers in case they come in contact with one of the 19 recalled dry shampoo products. Anyone who has the recalled products is urged to either throw them away or return the items from where they were purchased. Those who have experienced adverse reactions or quality problems with any of the recalled products can submit a report through the FDA website.