'Unacceptably high' levels of cancer-causing chemical found in acne products from Clinique, Clearasil and more. Here's what to know about benzene.

"Unacceptably high" levels of the cancer-causing chemical benzene have been discovered in a number of acne treatment products from several brands, including Reckitt Benckiser's Clearasil and Estée Lauder's Clinique. Scientists at the independent laboratory Valisure found levels of the chemical as much as 800-times over the regulatory limit during an independent analysis of the products. Benzene can cause a form of leukemia, and is considered a probable cause of non-Hodgkin lymphoma and multiple myeloma.

Valisure has petitioned the Food and Drug Administration (FDA) to recall the products, but the agency and product makers haven't yet pulled the items from shelves. The specific products found to contain high levels of benzene haven't been named, but also include acne cleansers and creams from Target's Up & Up brand, Walmart's Equate line and Taro Pharmaceutical Industries's Proactiv (which now goes by Alchemee).

Estée Lauder said in a statement shared with Reuters that Clinique uses benzoyl peroxide in one product, and that it is "is safe for use as intended." The makers of Clearasil also issued a statement to CBS News, saying it is "confident that all Clearasil products, when used and stored as directed on their labels, are safe." But experts from Valisure are sounding the alarm that prescription and over-the-counter acne treatments containing the benzoyl peroxide — a common and effective ingredient — may be broadly unsafe, in light of the new finding.

Benzene has previously been found in other cosmetic products. Suave voluntarily recalled two of its spray deodorants in 2022, and Johnson & Johnson Johnson issued a recall of five Neutrogena aerosol sunscreens after low levels of benzene were detected in samples of each.

But the latest finding is "substantially different," according to Valisure's statement. Prior recalls have predominantly been the result of contamination, but in this case, "the benzene in benzoyl peroxide products is coming from the benzoyl peroxide itself," Valisure co-founder and president David Light told Reuters. High levels of benzene were also found by the lab in the air outside of the of the products' containers, suggesting the chemical can leach out of packaging.

So what exactly is benzene?

“Benzene is a known carcinogen, which means that it is a cancer-causing ingredient,” Dr. Joshua Zeichner, director of cosmetic and clinical research in the department of dermatology at The Mount Sinai Hospital, tells Yahoo Life.

The chemical is colorless or light yellow and has a sweet odor to it. Benzene is often used to help make other chemicals, such as plastics, resins and nylon and synthetic fibers, as well as certain types of lubricants, dyes, detergents, drugs and pesticides, according to the Centers for Disease Control and Prevention (CDC).

What products typically contain benzene?

Benzene is practically everywhere in the environment. According to the American Cancer Society, it’s one of the 20 most widely-used chemicals in the U.S.

“We are actually exposed to low levels of benzene in our everyday life,” explains Zeichner. Exposure to the chemical can happen through inhalation, such as with spray deodorants, orally or through the skin.

Benzoyl peroxide, which is commonly recommended as a first line of treatment for acne, can form benzene as a byproduct. Benzoyl peroxide helps to kill bacteria that gets into pores and causes acne. It also has anti-inflammatory properties that help to calm the appearance of non-hormonal acne. The FDA considers benzoyl peroxide safe to use in both over-the-counter and prescription products at concentrations between 2.5% and 10%. But, when the ingredient comes into contact with oxygen, it can break down and release benzene.

In the case of aerosols, “benzene is commonly found at very low levels in aerosol personal care products like sunscreen and most recently antiperspirants,” explains Zeichner. “Benzene is not used as an ingredient in the aerosol product, but rather develops as a by-product in the bottle after formulation. Low levels of benzene are even found in carbonated beverages like colas.”

Another common source of benzene is cigarette smoke, which accounts for about half of the total U.S. population exposure to this chemical, according to the National Cancer Institute.

Benzene is also found in gasoline. "If you go to a gas station you’re exposed to high levels of benzene just filling up your car," Dr. Cy Rangan, a medical toxicologist with the California Poison Control System, tells Yahoo Life.

How harmful is benzene?

Long-term exposure — meaning a year or more — to benzene can cause “harmful effects on the bone marrow and can cause a decrease in red blood cells, leading to anemia,” according to the CDC. “It can also cause excessive bleeding and can affect the immune system, increasing the chance for infection.”

Prolonged exposure “to high levels of benzene in the air can cause leukemia, cancer of the blood-forming organs,” notes the CDC.

However, in the case of the Suave aerosol deodorants, the health risk appears to be low. Unilever stated that “based on an independent health hazard evaluation, daily exposure to benzene in the recalled products at the levels detected in testing would not be expected to cause adverse health consequences.”

Rangan explains that, although benzene is "one of a handful of chemicals in the world" that has a proven connection to cancer, "it doesn’t mean that if you get exposed you’re automatically going to get cancer."

He adds that, with deodorant — and presumably when spot treating acne as well — "you’re using a very small amount of the product, so trace amounts are unlikely to contribute to a lifetime risk of benzene exposure."

It's worth noting that benzoyl peroxide has been used extensively and has been approved to treat acne for more than 60 years. But for those concerned about possible benzene in benzoyl peroxide products, experts recommend speaking with a health care provider or dermatologist, who can recommend other acne-fighting treatments such as retinoids and salicylic acid.