Some dermatologists are recommending that people refrigerate benzoyl peroxide products such as Proactiv and Clearasil after an independent lab found they were contaminated with the potent carcinogen benzene.

The American Acne & Rosacea Society said Wednesday that storing benzoyl peroxide creams, gels and washes at refrigerated temperatures could minimize the risk of benzene exposure. “Benzoyl peroxide has been a very important part of the treatment of many patients with acne and also some other skin diseases,” according to the group, which has about 6,000 members.

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The testing lab Valisure filed a petition with the U.S. Food and Drug Administration on March 5 asking the agency to recall benzoyl peroxide acne treatments after finding high levels of benzene in the products, Bloomberg News has reported. Benzene levels increased when products underwent stability testing, including Proactiv’s 2.5% benzoyl peroxide cream, manufactured by Taro Pharmaceutical Industries Ltd., and 10% benzoyl peroxide cream from Reckitt Benckiser Group Plc’s Clearasil.

The findings came as a surprise given benzoyl peroxide has been used for five decades, AARS President James Del Rosso said in a statement. The group said more research is needed.

“We want to be sure that any guidance that is given and any decisions that are made are based as much as possible on solid scientific evidence,” Del Rosso said.

The FDA has said it would work to verify the accuracy of the data Valisure presented in its petition.

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