The World Health Organization’s cancer agency has classified talc, a mineral commonly used in cosmetics, as ‘probably carcinogenic’ for humans. This classification, based on limited evidence of a link to ovarian cancer in humans and strong evidence of carcinogenicity in animals, has sparked concerns among consumers but experts caution against drawing definitive conclusions.
Talc falls under Group 2B, a classification for compounds with significant evidence from animal research but limited proof of causing cancer in humans. The decision was based on “limited evidence” linking talc to ovarian cancer in humans, “sufficient evidence” linking it to cancer in rats, and “strong mechanistic evidence” showing carcinogenic signs in human cells, according to the WHO’s International Agency for Research on Cancer (IARC). The classification, while not a final verdict, calls for more research.
This announcement comes just weeks after US pharmaceutical and cosmetics giant Johnson & Johnson agreed to pay $700 million to settle allegations it misled customers about the safety of its talcum-based powder products. Despite the settlement, Johnson & Johnson did not admit wrongdoing and withdrew the product from the North American market in 2020.
Talc is a naturally occurring mineral mined in many parts of the world and is often used to make talcum baby powder. Most people are exposed to talc through baby powder or cosmetics, according to the IARC. In the Earth, talc and asbestos, another naturally occurring mineral, are found close together, leading to a possibility of asbestos contamination during talc mining and processing.
The IARC, known for its meticulous approach to determining cancer-causing substances based on expert assessments and peer-reviewed research, has found numerous studies consistently showing an increase in ovarian cancer rates among women using talc on their genitals. However, the agency could not entirely rule out asbestos contamination as a contributing factor, acknowledging that “a causal role for talc could not be fully established.” Their findings were published in The Lancet Oncology.
A 2020 summary of studies covering 250,000 women in the US did not find a statistical link between genital talc use and ovarian cancer risk. The American Cancer Society, while recognizing a marginal risk increase in some studies, emphasized that most data remains inconclusive, according to Indian Express.
The US Food and Drug Administration (FDA) evaluated cosmetics containing talc for asbestos, a known carcinogen, and found that most products had no measurable quantities of asbestos. However, this does not definitively prove that talcum powder itself is a carcinogen.
Expert opinion emphasizes that the IARC’s classification, based on observational studies that cannot prove causation, does not provide a “smoking gun” for talc causing increased cancer risk. Kevin McConway, a statistician at the UK’s Open University not involved in the research, cautions against misinterpreting the classification, stating that it only aims to assess the potential for cancer under unspecified conditions.
Dr Manish Singhal, writing for Indian Express, highlights the crucial distinction between talc containing asbestos and asbestos-free talc. Natural talc deposits can be contaminated with asbestos, a known carcinogen. Talc containing asbestos is classified as “carcinogenic to humans” by the IARC, while asbestos-free talc is not. He emphasizes that today, most cosmetic-grade talc is asbestos-free, and regulatory agencies like the FDA routinely evaluate the safety of talc-containing products.
In 2020, Health Canada identified a potential link between talc and ovarian cancer, but they did not recommend a complete ban on the product.
Also on Friday, the IARC classified acrylonitrile, a chemical compound used to make polymers, as “carcinogenic to humans,” its highest warning level. This classification was based on “sufficient evidence” linking acrylonitrile to lung cancer. Acrylonitrile-based polymers are widely used in various consumer products, including clothing fibers, carpets, plastics, and other materials.
