Talc is classified as probably carcinogenic by the World Health Organization’s (WHO) cancer agency, which has also classified acrylonitrile, a compound used in the production of polymers, as carcinogenic.
Experts from the International Agency for Research on Cancer (IARC), meeting in Lyon, France, published their results on Friday in the journal The Lancet Oncology.
They classified talc, a natural mineral mined in many parts of the world, as “probably carcinogenic” to humans, based on a combination of limited evidence of cancer in humans – including ovarian cancer – and sufficient evidence in laboratory animals.
According to them, exposure occurs mainly in occupational settings during the extraction, grinding or processing of talc, or during the manufacture of products containing it.
In the general population, it is done in particular through the use of cosmetics and body powders containing talc.
However, experts do not rule out some bias in studies that have shown an increase in cancer incidence. While the assessment focused on talc that did not contain asbestos, asbestos contamination of talc could not be ruled out in most studies on exposed humans, they say.
In June, US pharmaceutical giant Johnson & Johnson (J&J) reached a final settlement with courts in 42 US states in a talc case accused of causing cancer.
A review of studies published in January 2020, which included 250,000 women in the United States, found no statistical link between the use of talcum powder on the genitals and the risk of ovarian cancer.
In the 1970s, concerns arose about the contamination of talc by asbestos, which is often close in nature to the minerals used to make talc. Later studies pointed to a higher risk of ovarian cancer in talc users.
The WHO agency has also classified acrylonitrile, a volatile organic compound mainly used in the production of polymers, as “carcinogenic” to humans.
The decision is based on “sufficient evidence of lung cancer” and “limited” evidence of bladder cancer in men, according to the IARC.
These polymers are used in fibers for clothing, carpets, plastics for consumer products or automotive parts.
Acrylonitrile is also present in cigarette smoke. Air pollution is another source of exposure.