GLOBAL – The International Agency for Research on Cancer (IARC), a division of the World Health Organization (WHO), has assessed the carcinogenicity of two widely used per- and polyfluoralkyl substances (PFAS)—perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS).
The evaluation has resulted in the classification of PFOA as “carcinogenic to humans” (Group 1) and PFOS as “possibly carcinogenic to humans” (Group 2B).
PFAS, often referred to as “forever chemicals,” are known for their persistent nature, both in the human body and the environment.
Notable for their resistance to degradation, PFAS accumulate over time and have raised concerns globally due to their pervasive presence in drinking water.
These substances, including PFOS and PFOA, have been commonly utilized in non-stick and stain-resistant consumer products, such as cookware and food packaging.
In recent years, experts in the UK, the U.S., and worldwide have raised alarms about the widespread occurrence of PFAS in drinking water.
The body of evidence regarding the potential health risks associated with PFAS exposure has expanded, prompting certain state and national governments to initiate restrictions or bans on specific PFAS. Concurrently, some companies are voluntarily phasing out the use of these substances in their products.
IARC’s evaluation process
At a meeting held in Lyon, France, from November 7–14, 2023, a working group comprising 30 international experts from 11 countries reviewed published literature on PFOA and PFOS.
This thorough examination led to the categorization of PFOA as “carcinogenic to humans” (Group 1) based on sufficient evidence from cancer studies in experimental animals and strong mechanistic evidence in exposed humans, including epigenetic alterations and immunosuppression.
Additionally, there was limited evidence for cancer in humans, specifically renal cell carcinoma and testicular cancer.
PFOS, on the other hand, was classified as “possibly carcinogenic to humans” (Group 2B). The basis for this classification included strong mechanistic evidence across various test systems, including exposed humans, indicating epigenetic alterations and immunosuppression.
While there was limited evidence for cancer in experimental animals, the evidence regarding cancer in humans was deemed inadequate.
IARC emphasized that the general population, not engaged in industrial work involving PFOS and PFOA, primarily encounters these chemicals through food consumption and drinking water.
The agency acknowledged the ubiquitous presence of PFOA and PFOS in the environment, even reaching remote areas.
This latest classification by IARC adds to the growing body of knowledge about the potential health risks associated with PFAS exposure and underscores the need for continued research, regulatory measures, and public awareness efforts to address these concerning substances.