Lawsuit Claims Decades of Exposure to Known Carcinogens in Professional Hair Products
A California hair stylist diagnosed with bladder cancer in 2023 has filed a lawsuit against L’Oreal and 10 other beauty companies, alleging their hair dye products caused his disease. Hector Corvera, a hairstylist for 40 years in California’s Central Valley, filed the suit in Los Angeles last month through attorney Allen Smith, who previously won a $700 million settlement against Johnson & Johnson in talcum powder litigation. Multiple occupational studies dating back to the 1970s have found hairdressers face an increased risk of bladder cancer due to chemicals known as aromatic amines present in hair dyes. One is 4-aminobiphenyl (4-ABP), a known human carcinogen discovered in commercial hair products during a 2003 FDA study.
5 Key Points
- California hairstylist Hector Corvera is suing L’Oreal and 10 other companies after being diagnosed with bladder cancer allegedly caused by chemicals in hair dyes he used throughout his 40-year career.
- Attorney Allen Smith, who won a $700 million settlement against Johnson & Johnson in talcum powder cases, claims hair dyes contain “known chemicals that cause cancer” and plans to represent numerous stylists in similar lawsuits.
- A 2003 FDA study found that 8 out of 11 commercial hair dyes contained 4-aminobiphenyl (4-ABP), a known human carcinogen banned from commercial production in the U.S. since the 1950s.
- The World Health Organization’s cancer research wing classified the hairdressing occupation as “probably carcinogenic to humans” in 2010, citing “consistent evidence” of “excess risk” for bladder cancer.
- Women who regularly use permanent hair dye showed a 9% increased risk of breast cancer in a 2020 NIH study of nearly 47,000 women, with women of color experiencing a 60% increased risk compared to 8% for white women.
What Led a California Hair Stylist to Sue Major Beauty Companies?
Hector Corvera never imagined his career choice would lead to cancer. Born to Mexican-American agricultural farmers in California’s Central Valley, he became a hairstylist four decades ago to escape the physically demanding fieldwork of his parents. “Your first day out of beauty college, you’re nervous, and you don’t want to mess up,” Corvera recalled of his early career. He chose hairdressing because it promised air conditioning and steady work – “people’s hair always grows,” he reasoned.
In 2023, Corvera received a bladder cancer diagnosis that changed everything. During an appointment with his urologist, Corvera mentioned his profession. “He says, what do you do for a living? And I said, ‘I’m a hairdresser,'” Corvera recounted. The doctor responded: “Hmm, that explains it.” Initially too overwhelmed to inquire further, Corvera later connected with lawyers researching cases of hair stylists with cancer, leading him to investigate potential links between his occupation and disease.
The lawsuit, filed in Los Angeles in January 2025, names L’Oreal, Wella, Clairol, John Paul Mitchell Systems, Joico, and All Nutrients among the defendants – companies allegedly manufacturing the dyes Corvera used throughout his career. The legal complaint states his cancer diagnosis “was a direct and proximate result of the unreasonably dangerous and defective nature of the Defendants’ hair color products and the chemicals contained therein.”
“It’s ruined my life. I’m not normal anymore, having to think of it every day, whether this is going to come back,” Corvera said, describing the ongoing psychological impact of his diagnosis. His case highlights the plight of many hairstylists who may have unknowingly exposed themselves to carcinogens for decades.
What Scientific Evidence Links Hair Dye to Cancer Risk?
Studies examining links between hair dyes and cancer date back to the 1970s. A 1975 study tested approximately 170 permanent hair dyes and found the vast majority altered the genetic makeup of bacteria in laboratory experiments, raising questions about cancer-causing capabilities. Concurrent research by the National Cancer Institute found that a major hair dye ingredient caused cancer when fed to rodents.
According to the FDA, the cosmetic industry “reformulated coal-tar hair dye products” to remove certain harmful chemicals in response to these early findings. However, a follow-up study in 2003 by the National Center for Toxicological Research, part of the FDA, discovered other harmful chemicals persisted in commercial hair dyes decades later.
This 2003 study found 4-aminobiphenyl (4-ABP), an aromatic amine and known human carcinogen, in eight out of 11 tested U.S. commercial hair dye products, “in black, red and blonde hair dyes but not in brown hair dye.” The discovery was particularly alarming because 4-ABP can cause bladder and liver cancer, and its commercial production had been banned in the United States since the 1950s due to its carcinogenicity.
“There are actually many chemicals that are toxic that are in these products,” said Adana Llanos, an associate professor of epidemiology at Columbia University. “How is it that 4-ABP is still being found in modern-day hair dye? That chemical in particular, and many others should not be in products that people have easy access to because we know they are harmful and toxic.”
The lawsuit alleges these companies misrepresented to the FDA that they removed carcinogenic chemicals from their products decades ago, while these substances allegedly remain in commercial hair dyes today. Adding to consumer concerns, Llanos noted these chemicals typically don’t appear on product labels because they materialize during manufacturing or when the dye is mixed with hydrogen peroxide and color accelerant in salons.
What Health Risks and Injuries Are Associated With Hair Dye Exposure?
Studies have identified numerous potential health risks associated with long-term exposure to hair dye chemicals, particularly for professionals like Hector Corvera, who face daily contact with these substances. Research has documented several specific health concerns:
- Bladder cancer – Identified as having a “small but fairly consistent increased risk” among hair professionals, according to the American Cancer Society
- Liver cancer – Linked to 4-ABP exposure, a known human carcinogen found in hair dyes.
- Breast cancer – Sister Study showed a 9% increased risk in regular users and a 60% higher risk for women of color
- Basal cell carcinoma – Slight elevation in risk noted in 2020 BMJ study
- Ovarian cancer – Also identified as having a slightly higher risk in the BMJ research
- DNA damage – Aromatic amines in hair dye have demonstrated the ability to alter genetic material
- Thyroid hormone disruption – Studies suggest potential endocrine system effects
- Immune system impairment – Research indicates possible immune response alterations
- Reproductive issues – Including potential decreased fertility and pregnancy complications
- Chemical sensitivity reactions – Beyond cancer, repeated exposure can trigger respiratory issues and skin conditions.
The risk profile differs significantly between professionals like Corvera and occasional consumers. Hairstylists experience much higher cumulative exposure through inhalation and skin contact over decades of work. The World Health Organization’s cancer research agency classifies explicitly the occupation as “probably carcinogenic to humans,” with risk increasing substantially after ten years in the profession.
“Hair dyes are full of carcinogens,” emphasized McTiernan. “For hairdressers, it’s clear that the occupation is problematic.” Exposure occurs during application and mixing, with many harmful chemicals becoming active only when combined with developers and oxidizing agents in the salon environment.
Risk assessment remains more complex for consumers, with some studies showing minimal association and others indicating potential concerns, particularly for frequent users of darker dye shades. The significant discrepancy in risk between white women (8% increased breast cancer risk) and women of color (60% increased risk) highlights how formulation and concentration differences may substantially impact safety profiles.
Corvera’s lawsuit speaks directly to these occupational hazards, alleging manufacturers were aware of these risks for decades but failed to reformulate products adequately or provide proper warnings to salon professionals.
Why Are Hairdressers at Higher Risk for Bladder Cancer?
Multiple large-scale studies have established that hairdressers face an elevated risk of bladder cancer compared to the general population. A comprehensive 2010 analysis by German researchers examined more than 42 previous studies and found “an increased and statistically significant risk for bladder cancer among hairdressers,” particularly for those in the profession for more than 10 years.
“That’s an important piece of information in all of this: increased dose equals increased risk,” explained Anne McTiernan, an epidemiologist at the Fred Hutchinson Cancer Center in Seattle. The German study concluded there is a “causal association between bladder cancer and a job held as a hairdresser.”
Based on this and other scientific evidence, the World Health Organization’s cancer research wing, IARC, classified the hairdressing occupation as “probably carcinogenic to humans” in 2010, citing “consistent evidence” of “excess risk” for bladder cancer in hairdressers and barbers.
“Hair dyes are full of carcinogens,” McTiernan stated. “For hairdressers, it’s really clear that the occupation is problematic.” She explained that exposure occurs through inhalation and skin contact, noting that standard latex gloves may not provide adequate protection against these chemicals.
According to the American Cancer Society, studies among people exposed to hair dyes at work have found “a small but fairly consistent increased risk of bladder cancer.” This occupational hazard has raised questions about whether better protective equipment and ventilation systems might reduce exposure risk for salon professionals.
Do Hair Dye Users Also Face Increased Cancer Risks?
While evidence for cancer risk among hair care professionals is relatively robust, research on consumers who use hair dye regularly shows less definitive but still concerning patterns. The most extensive study examining this question, the 2020 NIH Sister Study, analyzed data from nearly 47,000 women to investigate associations between cancer risk and hair dye use.
Alexandra Wright, a principal investigator at the National Institutes of Health who co-authored the study, said her research “provides strong scientific evidence in support of the link” between permanent hair dye use and increased breast cancer risk. The study found women who regularly used permanent hair dye in the year before enrolling were 9% more likely to develop breast cancer than women who did not use such products.
Most alarming was the disparity in risk between demographic groups. Women of color had a substantially higher risk – 60% increased risk compared to just 8% for white women. “The findings from the Sister Study definitely do raise some eyebrows,” said Tiffany Onger, an oncologist at Cleveland Clinic. “They were able to find this relationship or association that people who use permanent hair dye regularly have a higher risk of developing cancer, breast cancer, compared to people who don’t, and that risk was even more pronounced for Black women.”
The heightened risk for women of color appears linked to the shade of dye used. “We saw that women who use darker shades of hair dye have a substantially higher risk,” explained Llanos, noting darker pigmentation requires greater concentrations of chemicals. “We know that Black women and African American women, due to the color of their hair, in particular, if they’re covering grays, are going to tend to use darker hair dyes to try to match their natural hair color. But it’s actually these darker dyes that are more problematic,” Onger added.
However, researchers emphasize that the Sister Study only shows association, not causation. A different 2020 study published in the BMJ Medical Journal found no positive association between personal hair dye use and risk for most cancers. However, it noted a “slightly higher risk” for basal cell carcinoma and certain types of breast and ovarian cancers. The study’s lead researcher, Yin Zhang, concluded: “Current evidence regarding the carcinogenic potential of permanent hair dye use is inconclusive.”
How Are Companies and Regulators Responding to These Concerns?
The hair dye industry faces limited regulatory oversight in the United States. Unlike pharmaceuticals, cosmetic products and ingredients don’t require FDA safety checks before entering the market. Instead, manufacturers are responsible for ensuring product safety.
“Cosmetics undergo no FDA testing before they go on the market. So the guinea pigs, so to speak, are the people that use or wear the cosmetics,” said attorney Allen Smith, who is representing Corvera and plans to file suits for other stylists with similar claims.
When NBC News inquired whether hair manufacturers had informed the FDA about removing carcinogenic aromatic amines like 4-ABP from their products, an agency spokesperson responded that “under the law, cosmetic products and ingredients generally do not need FDA premarket approval, and hair dye manufacturers are not obliged to inform FDA if they choose to remove coal-tar hair dyes from their products.”
Most companies named in Corvera’s lawsuit declined to comment on the litigation when contacted by NBC News. One defendant, Coty, stated they no longer make or sell hair dye products in the U.S., adding, “the claims against Coty are unsubstantiated and without merit.” Similarly, Bristol Myers Squibb claimed “no liability” for products manufactured by Clairol, which it sold in 2001.
Smith, who previously secured a $700 million settlement from Johnson & Johnson over cancer-linked talcum powder, has made forceful allegations against the hair dye industry: “We’re not talking about chemicals in hair dyes that might be carcinogenic or possibly carcinogenic. These are known chemicals that cause cancer.”
Corvera hopes his lawsuit will drive industry change regarding how these products are formulated, distributed, and marketed. “I think they need to be clear and honest with the consumer and tell them what’s in the product,” he said. “Give some warnings if there is such a thing that is causing this, and be honest with the people.”
FAQ
Q: What chemicals in hair dye are linked to cancer?
A: Studies have found aromatic amines, particularly 4-aminobiphenyl (4-ABP) in hair dyes. 4-ABP is a known human carcinogen that can cause bladder and liver cancer. These chemicals often don’t appear on ingredient lists because they form during manufacturing or when dyes are mixed with developers in salons.
Q: How do hairstylists get exposed to these chemicals?
A: Hairstylists are exposed through skin contact and inhalation while mixing and applying hair dyes. Standard latex gloves may not provide adequate protection. The risk increases with years of exposure, with studies showing significantly higher cancer rates for those working as stylists for more than 10 years.
Q: Is there a difference in cancer risk between hair dye colors?
A: Yes, darker hair dyes typically contain higher concentrations of chemicals and have been associated with greater cancer risk. The 2003 FDA study found 4-ABP in black, red, and blonde dyes but not in brown dyes. The Sister Study showed women using darker shades had substantially higher breast cancer risk.
Q: Do consumers who dye their hair face cancer risks similar to those of professional hairstylists?
A: The evidence for consumers is less conclusive than for professional stylists. The 2020 Sister Study found women who regularly used permanent hair dye had a 9% increased risk of breast cancer, with a 60% increased risk for women of color compared to 8% for white women. However, other studies have found minimal or no association for most cancer types.
Q: Why aren’t these chemicals regulated or banned if they’re known carcinogens?
A: Unlike pharmaceuticals, cosmetic products in the U.S. don’t require FDA safety testing before market release. The FDA doesn’t have the authority to require premarket approval for cosmetics, and manufacturers aren’t obligated to report ingredient changes. This regulatory gap allows potentially harmful chemicals to remain in products even after safety concerns are identified.
Q: What protective measures can hairstylists take to reduce their exposure risk?
A: Experts suggest improved ventilation in salons, specialized protective gloves rather than standard latex, and potentially wearing masks during mixing and application. However, without complete ingredient disclosure, it remains challenging for stylists to protect themselves from unknown chemicals fully.
Q: How has the industry responded to the lawsuit and cancer risk allegations?
A: Most companies named in the lawsuit declined to comment. Coty stated they no longer make hair dye products in the U.S. and called the claims “unsubstantiated and without merit.” Bristol Myers Squibb claimed no liability for Clairol products they sold in 2001. There has been no industry-wide acknowledgment of the potential risks or commitment to reformulation.
Citations
Snow, K., Salam, Y., & Brooks, A. (February 13, 2025). ‘I’m not normal anymore’: Hair stylist sues companies over link between hair dye and cancer. NBC News. https://www.nbcnews.com/health/health-news/-hair-stylist-sues-beauty-brands-bladder-cancer-rcna191706
