The same chemicals found in pipes, pesticides and floor tiles are also present in some wigs, braiding hair and hair extensions, a new study published Wednesday in the journal Environment & Health found.
Researchers at the Silent Spring Institute, a scientific research nonprofit organization based in Massachusetts, tested 43 hair extension products purchased online and from local beauty supply stores and identified 169 chemicals present overall, including dozens of harmful substances such as flame retardants, pesticides and compounds used to stabilize plastics.
A dozen of the compounds found are listed under California’s Proposition 65, known as the Safe Drinking Water and Toxic Enforcement Act of 1986, which warns residents of chemicals known to cause birth defects, cancer and reproductive issues. Additionally, 17 compounds that have been linked to breast cancer were found in 36 samples tested, the researchers said.
In recent years, researchers across the country have been sounding the alarm over harmful hair products, many of which are used and marketed to Black women. Consumer Reports revealed last year that carcinogens were found in samples of 10 popular synthetic braiding hair brands. Nine of the 10 samples also tested positive for lead.
Chemical hair relaxers also pose risks. The Black Women’s Health Study in 2023 found a 50% increased risk of uterine cancer in postmenopausal Black women who used chemical hair relaxers more than twice a year or used the products for more than five years, compared to a cohort who rarely or never used relaxers. And a 2022 study from the National Institute Environmental Health Sciences found that women who used hair straighteners more than four times per year had more than a double chance of developing uterine cancer than those who didn’t use the products. (Uterine cancer accounted for about 3% of new cancer cases in the U.S. in 2025.)
Harsh chemicals found in synthetic braiding hair and other hair extensions can be absorbed through the scalp, causing irritation, burning and redness, according to Dr. Chris Pernell, director of the NAACP Center for Health Equity. They can also be inhaled — particularly when heated during styling — and absorbed through a person’s hands.
Pernell, who was not involved with the new research, said in an email that braiders or stylists may be most at risk for dermal absorption through their hands and fingers, “due to ongoing handling of the products, which they may transfer to their mouths and faces when eating.”
She said the long-term impact of being exposed to chemicals through hair extensions requires additional research.
“While some of these compounds are known to be carcinogens, such as benzene, or have neurotoxicity like lead, it is unclear whether these chemicals in hair products lead to cancer or neurological impairments,” she said. However, the fact that these chemicals are present in commonly used products and pose a hazard “warrants attention, inquiry, and regulation.”
Hazardous hair
The new study tested 43 synthetic and human hair products. Human hair was classified as raw (unprocessed) or virgin (minimally processed); several types of synthetic hair were included, as well as blended synthetic and human hair, referred to as mastermix.
Elissia Franklin, a research scientist at the Silent Spring Institute and the lead author of the new study, said that 41 out of the 43 products tested contained hazardous chemicals. The two products deemed to be safe, from the Black-owned brands Rebundle and Latched & Hooked, were labeled as “non-toxic” or “toxic-free.”
The study also checked its findings against chemicals listed in the PlastChem database, an international scientific initiative that classifies chemicals in plastic. Several of the samples contained chemicals that PlastChem lists as hazardous, particularly in samples of raw, virgin and blended hair.
Among the chemicals identified were benzyl chloride, a compound used in the production of sanitizers and plasticizers that is possibly carcinogenic and can cause harm to the lungs and digestive tract.
Seventeen of the chemicals identified were linked to breast cancer, including dibutyl phthalate and DEHP, which are both used to increase flexibility in plastics.
Four samples tested contained 23 so-called organotin compounds. These samples contained “unspecified” synthetic hair, the study said.
“It was the organotin compounds that stood out to us, in particular because that’s not commonly found in consumer products,” Franklin said. “It is used in polyvinyl chloride (PVC) as a stabilizer. However, we do know that they are linked to cancer and hormone disruption as well, and they’re really bad for the environment.”
Lariah Edwards, an associate research scientist at the Columbia University Mailman School of Public Health, said this is the first time she’s heard of organotins in hair extensions.
“This is definitely concerning,” she said, especially as it relates to endocrine disruptors, which studies have shown are linked to obesity and birth defects.
For Black women, hair-braiding is often seen as a protective style — it allows the hair to grow and gives it a break from relaxers, Edwards said.
“To find out that this style is also exposing them to toxic chemicals is really unfortunate,” Edwards added, calling the findings another “catch 22 for Black women.”
A push for legislation
More research is needed to determine the exact routes of exposure for chemicals in hair extensions, Franklin said. Still, the responsibility lies on the companies, who need to remove the chemicals from their products. According to the Silent Spring study, hair extension products rarely disclose chemical ingredients on packaging.
On a legislative level, some efforts are moving in a positive direction. Last summer, Rep. Ayanna Pressley, D-Mass., along with three other members of Congress, reintroduced the Safer Beauty Bill Package to expand the Food and Drug Administration’s regulation of cosmetics. One of four bills in the package includes the Cosmetic Safety Protections for Communities of Color and Salon Workers Act.
In 2023, the FDA proposed a ban on using formaldehyde in chemical relaxers. Since then, however, the agency has missed four deadlines to act, including its most recent deadline of Dec. 31. Some changes are also happening at the local level. New York’s State Assembly Bill 2025-A7001 would require that hair extensions, wigs and braiding hair containing toxic chemicals must be labeled with a warning.
For people who are concerned about their hair extensions, braiding hair and wigs, Franklin said to look out for brands that label themselves as nontoxic or toxic-free. She also suggested a possible at-home remedy that is commonly found in kitchen cabinets: apple cider vinegar.
“We have some support that apple cider vinegar rinses of the hair could reduce the number of chemicals in it — but it’s limited,” she said.
Pernell, the NAACP Center for Health Equity director, said that people can also limit the frequency of wearing synthetic braids or hair extensions and look for safer alternatives, including plant-based products. She also emphasized the importance of consumer advocacy and the demand for safer products.
“Consumer advocacy plays a vital role in health advocacy,” Pernell said. “Just as we fight for clean air, safe streets, access to green spaces, and healthy, affordable food, the public and historically marginalized communities, particularly, have the right not to bear disproportionate risks from consumer products.”
