High levels of a chemical known to cause cancer have been found at unacceptably high levels" in popular acne products from brands like Proactive, Target's Up & Up, Clinique, and Clearasil, according to a recent report by independent laboratory Valisure. Benzene, a known human carcinogen, was found to develop in products with benzoyl peroxide, a chemical used to treat acne, at a level of over 800 times the concentration limit of 2 parts per million set by the U.S. Food and Drug Administration, the March 6 report said. The drug product was found to be "fundamentally unstable" especially when stored at high temperatures. The report found a Proactiv product left in 158 degrees Fahrenheit of a hot compact car resulted in the detection of benzene at around 1,270 times the Environmental Protection Agency's calculated threshold for increased cancer risk. "There is not a safe level of benzene that can exist in any skin care product, over the counter or prescription," Christopher Bunick, MD, PhD, Associate Professor of Dermatology at Yale University, said in a statement for Valisure. The report also found that benzene can leak out of packaging and "pose a potential inhalation risk" to consumers, according to the report. The company sent a citizen petition to the FDA on Tuesday describing its report and requesting "recalls and a suspension of sales for products containing the active pharmaceutical ingredient benzoyl peroxide."