IARC’s Determination on Talc is At Odds with Best Available Science

Arlington, VA, August 19, 2025 – The Essential Minerals Association (EMA) disagrees with the International Agency for Research on Cancer’s (IARC) recently finalized Monographs Volume 136: Talc and Acrylonitrile. The working group that met in June 2024 concluded that talc is “probably carcinogenic to humans (Group 2A) on the basis of limited evidence for cancer in humans, sufficient evidence in experimental animals, and strong mechanistic evidence in human primary cells and experimental systems (Stayner, et al., 2024).” The strongest available evidence across multiple fields of study clearly demonstrates that talc does not cause cancer.

EMA’s reaction is based on the following observed deficiencies with the IARC meeting and its conclusion:

• Regarding “limited evidence for cancer in humans:” data remains inconclusive although several new studies are cited. The Working Group acknowledged that “…bias from differential exposure misclassification could not be excluded based on a bias analysis conducted by the Working Group…” Accordingly, there is no change to the IARC Volume 93 statement that there is “limited evidence that talc causes ovarian cancer.”Moreover, it appears that consideration was not given to a recent and significant systematic review by Boon et al. (2024) that found “that epidemiology studies do not support a causal association between occupational, medicinal, or personal talc exposure and any cancer in humans.” Furthermore, the Working Group’s conclusionin the IARC Monograph offers contradictory information, stating that talc (not containing asbestos) is “probably carcinogenic to humans” but also asserting “no excess risk” of lung or stomach cancer was observed in studies of workers in mines.
  
• Regarding “sufficient evidence in experimental animals:” no new evidence was cited substantiating this claim. Studies cited were previously incorporated in the National Toxicology Program (NTP) 1993, with only one more recent, questionably relevant, 2009 study previously evaluated by IARC in 2010. One panelist noted, “Several experts did not agree with the reclassification of talc on the basis of the single animal study and an inadequacy of meeting a majority of the key characteristics…” (Ghio). Conclusions from this study have been challenged due to various issues, including the “extremely high exposures that likely resulted in lung particle overload,” etc. Additionally, the Working Group’s determination of sufficient evidence in experimental animals is inconsistent with the recent determination by the Risk Assessment Committee (RAC) of the European Chemicals Agency (ECHA) in its consideration of risks associated with talc. While EMA has serious concerns about the process and conclusions reached in the RAC review, we note that the opinion published July 9, 2025, definitively states that “[t]he available animal data is considered limited evidence that talc can cause an increase in incidence of lung tumours in female rats” (emphasis in original), and concludes that “the available animal data provide limited evidence for the carcinogenicity of talc” (emphasis in original). EMA is unable to understand how the Working Group came to such a different conclusion from the same body of evidence.
  
• Regarding “strong mechanistic evidence:” As summarized in Lancet Oncology, “consistent and coherent mechanistic evidence was based on studies in which asbestos contamination of talc was highly unlikely.” However, it is not clear how the original wide range of confidence in the characterization of the historical talc was addressed. It appears that consideration was not given to a significant and recent systematic review by Prueitt et al. (2024) where it is stated that the “systematic review of the experimental animal carcinogenicity and mechanistic evidence for talc indicates that an association between talc exposure and cancer is not expected in humans.” Notably, Ghio shares “a review of 10 key characteristics of carcinogenic agents provided strong support only for talc’s 'inducing chronic inflammation' and 'altering cell proliferation,' which reflect the basic pathway of inflammation,” and “Several experts did not agree with the reclassification of talc on the basis of the single animal study and an inadequacy of meeting a majority of the key characteristics.”  
  

Talc is an important mineral used in products throughout the world, and the output of the IARC working group brings unnecessary confusion and misunderstanding to this essential mineral. The overwhelming weight of scientific evidence does not support IARC’s conclusions. If the agency were to utilize the best available science, it would be abundantly clear that talc does not cause cancer.

#

The Essential Minerals Association is the representative voice for companies that extract and process a vital and beneficial group of raw materials and minerals, which are the essential ingredients for many of the products used in everyday life. EMA ensures that the voices of its member companies and the socio-economic benefits they provide – from mining to end-use products – are heard by government leaders as well as the general public. Visit essentialminerals.org to learn more. 

References:

Stayner, L., Carreón-Valencia, T., Demers, P., Fritz, J., Sim, M., Stewart, P., et al. (2024). Carcinogenicity of talc and acrylonitrile. The Lancet Oncology. https://doi.org/10.1016/S1470-2045(24)00384-X

International Agency for Research on Cancer. (2010). Volume 93: Carbon Black, Titanium Dioxide, and Talc. IARC Monographs on the Identification of Carcinogenic Hazards to Humans.

Boon, D., Goodman, J., Colonna, K., Espira, L. & Prueitt, R. (2024). A systematic review of the epidemiology evidence on talc and cancer. Critical Reviews in Toxicology, 54(6), 394-417. https://doi.org/10.1080/10408444.2024.2351081

National Toxicology Program.  Toxicology and carcinogenesis studies of talc (CAS No. 14807-96-9) (non-asbestiform) in F344/N rats and B6C3F1 mice (inhalation studies).  Natl Toxicol Program Tech Rep Ser 1993; 421:1-287.

Prueitt, R., Drury, N., Shore, R., Boon, D. & Goodman, J. (2024). Talc and human cancer: a systematic review of the experimental animal and mechanistic evidence. Critical Reviews in Toxicology, 54(6), 359-393. https://doi.org/10.1080/10408444.2024.2349668

Mundt, K. A., Santamaria, A. B., Thompson, W. J., Bates, C. A., Boles, C., Dotson, G. S., & Yong, M. (2022). Carcinogenicity of Poorly Soluble Low Toxicity Particles: Commentary on Epidemiology as a Risk Assessment "Reality Check". Frontiers in public health, 10, 920032. https://doi.org/10.3389/fpubh.2022.920032

Ghio, A. J. (2025). Talc, Pleurodesis, and Cancer. Am. J. Respir. Crit. Care Med, 211(2), 295-296. https://doi.org/10.1164/rccm.202407-1376RL

International Agency for Research on Cancer. (2025). Volume 136: Talc and Acrylonitrile. IARC Monographs on the Identification of Carcinogenic Hazards to Humans.

ECHA. Opinion proposing harmonised classification and labelling at EU level of Talc (Mg3H2(SiO3)4) (2025). Retrieved 2025, from https://echa.europa.eu/documents/10162/03b74f7b-10ca-3e74-514b-e7f2b24c98ec.