Benzene seems to have cropped up everywhere in recent years. First, it was hand sanitizers with “unacceptable levels” of the carcinogen. Then there were recalls of antifungal foot sprays and alarming reports of tainted deodorants, dry shampoos and sunscreens.
Some of these findings have driven panicked news headlines and social media posts. On TikTok, wellness influencers have warned people to stop wearing sunscreen; one doctor on the platform even compared using dry shampoo with benzene to smoking cigarettes. Several class-action lawsuits have also been filed over the findings.
Benzene, which is found naturally in crude oil, isn’t intentionally added to these products. Rather, it’s used to manufacture chemicals such as dyes, detergents, paints and plastics. It can end up in personal care products when the chemicals in them aren’t purified enough, or when certain active ingredients in products react with each other or break down.
There isn’t data yet to suggest that low levels of exposure to benzene from personal care products carries significant health risks. And some experts have cautioned that many of the most alarming findings about benzene have come from a single testing lab that has been criticized for straying from standard testing methods.
Still, given that high levels of benzene exposure have been linked to cancer, experts say it’s worth taking a closer look at dry shampoos, sunscreen and more.
What does the research show about benzene?
Much of the research so far on benzene looks specifically at regular exposure to high levels of the chemical in occupational settings.
Evidence that benzene might cause cancer in humans comes from observations of workers in pharmaceutical and petroleum-based industries going back to the 1920s. But it wasn’t until 1987 that the International Agency for Research on Cancer said there was “sufficient evidence” that benzene was carcinogenic, based on rigorous studies of humans and animals. Today, the World Health Organization, the U.S. Environmental Protection Agency and the U.S. National Toxicology Program all agree that benzene can cause cancer, particularly leukemia.
There is also evidence that breathing in high levels of benzene over long periods of time is linked to other blood cancers and lung cancer, as well as anemia, a decreased ability to fight off infections and irregular menstrual periods in female workers.
Occupational safety officials worldwide have generally recommended that exposure in the workplace be limited to one part of benzene per million parts of air, or one p.p.m., over an eight-hour workday.
The rest of us are exposed to benzene, too — through vehicle emissions, cigarette smoke and gas stoves — but at much lower levels. “We cannot totally avoid exposure in our modern environment,” said Emily Barrett, an epidemiologist at the Rutgers School of Public Health. But one study estimated that an average person’s environmental exposure would be below 0.015 p.p.m. in a day — or nearly a hundred times lower than the occupational limit.
What do we know about benzene in personal care products?
As there have been more reports of benzene in personal care products, scientists have started looking into whether low levels of the chemical might have health effects.
A handful of lab studies have shown that at least some amount of benzene can penetrate the skin barrier. And researchers are concerned that ingredients that help lotions and sunscreens melt into the skin may speed up absorption, said Kurunthachalam Kannan, a toxicologist now at the New York State Department of Health whose research has also found benzene in personal care products.
Because benzene can easily evaporate, people might also breathe in some of the chemical while applying a product topically, meaning they could get exposed through both routes, said Luoping Zhang, a toxicologist at the University of California, Berkeley. But the fact that it evaporates quickly suggests dermal exposure is not nearly as much of a concern as being exposed to benzene regularly in the air, as workers might be on the job.
The limited research on this so far does not point to any significant risk. In one study, a group of academic researchers examined data from more than 27,000 people who had used prescription creams containing benzoyl peroxide, which acts as an antiseptic. When they compared it to data from patients who had no exposure to benzoyl peroxide, the researchers found no increased risk for cancers associated with benzene among those using the creams.
Still, some experts said they were concerned about these potential exposures given that these products are applied directly to the body — usually daily — and in small, poorly ventilated spaces like bathrooms.
The amount of benzene Americans are exposed to may be increasing: While national surveys show that levels of benzene in the air have declined — thanks to stricter limits on gasoline — markers of benzene in urine samples from Americans have increased in recent decades. At the same time, scientists have found more products may have benzene, including diapers, disposable wipes, tampons and sanitary pads.
The discovery of benzene in these products highlights gaps in the regulatory oversight of personal care product safety, said Ami Zota, an associate professor of environmental health sciences at the Columbia University Mailman School of Public Health. A lot of product safety testing is voluntary, she said, “so the industry sort of sets its own norms.”
Why is there so much attention on benzene specifically?
Much of the interest around benzene contamination in personal care products has been driven by a small drug testing company based in New Haven, Conn. The company, Valisure, has reported finding benzene contamination in hand sanitizers, body sprays, sunscreens, dry shampoos and acne medications containing benzoyl peroxide. The findings from some of Valisure’s reports have spread widely on social media platforms such as TikTok and Truth Social.
But some scientists have questioned Valisure’s methodology, arguing its testing protocol frequently involves heating products beyond temperatures that would ever come to pass in regular life, which could accelerate the breakdown of ingredients and suggest a higher risk of benzene exposure than consumers would actually face.
“They are known for making wild comparisons in their reports,” said Michelle Wong, a chemist and science educator in Australia who has criticized Valisure’s work online.
Companies do often test products at elevated temperatures to simulate how they would break down over time and to set expiration dates, said Kelly Dobos, a consultant cosmetic chemist and adjunct professor of cosmetic science at the University of Cincinnati. But heating products to higher temperatures than is recommended for this type of stability testing could give faulty results, said David Keire, director of the office of pharmaceutical quality research at the F.D.A. “If you light something on fire, it will burn,” he said.
In an interview, David Light, the president and co-founder of Valisure, defended the company’s methods, which also included tests at lower temperatures, as scientifically sound.
Others have called the motivation behind Valisure’s work into question, given that it stands to benefit financially from increased regulation and product testing spurred by its findings. Mr. Light said that while the company was for-profit, its focus was on protecting consumers and improving public health.
What should you do about it?
Experts emphasized that there’s no need to panic about benzene in personal care products, but several suggested making sure you store these items properly to avoid them breaking down. Here are a few simple steps to minimize your exposure.
Sunscreen: None of the experts interviewed suggest ditching sunscreen out of fear of benzene. Even in tests by Valisure, the majority of sunscreens did not have detectable levels.
“The benefits of sunscreens are well known,” Dr. Zhang said. “The risk is something that we’re assuming is there and we’re trying to figure out.” But if you want to err on the side of caution, you should avoid storing sunscreen in your car and stay away from aerosols. Many of the products found to contain benzene are aerosols. Benzene may be more likely to end up in these formulations because it can contaminate the propellants.
Dry shampoos: If you are concerned about potential benzene exposure, try switching to dry shampoos that come in powder formulations instead of aerosol products, Dr. Barrett said.
Acne creams: If you want to continue to use benzoyl peroxide products, store them in a cool, dark place like a cabinet or fridge, Ms. Dobos said: That will help their ingredients remain stable for longer. You can also speak with a doctor about alternatives to benzoyl peroxide that may work for you. And you should always check your products against the F.D.A.’s searchable list of recalled products and safety alerts.
