Volume 135: Perfluorooctanoic acid and perfluorooctanesulfonic acid

We are pleased to announce that the results of the recent IARC Monographs evaluation of the carcinogenicity of perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) have now been published in The Lancet Oncology. This summary article presents the conclusions of IARC Monographs Meeting 135.

PFOA was previously evaluated by the IARC Monographs in 2014 (Volume 110), and PFOS was evaluated at the present meeting for the first time.

PFOA and PFOS are per- and polyfluoroalkyl substances (PFAS) that are extremely resistant to degradation. First produced in the 1940s, PFOA has been used extensively in fluoropolymer manufacture and applications; for surface coatings conferring stain, oil, and water resistance on household products, carpets, textiles, leather products, and food and feed packaging; personal care products; electrics and electronics; and construction materials. Used similarly to PFOA in waxes, carpets, and food and feed packaging, PFOS additionally has applications in the fabrication of imaging devices, semiconductors; in photolithography and electroplating; and in insulation, dyes, and ink; as well as in class B firefighting foams known as aqueous film-forming foams.

PFOA and PFOS occur ubiquitously in the environment, with high levels at pollution sources such as industrial sites and in firefighter-training areas, waste deposits, and contaminated wastewater. PFOA and PFOS may also be present in contaminated food, especially fish, seafood, and eggs. Occupationally exposed populations have some of the highest levels of exposure, mainly via inhalation. The general population in communities that are not near pollution sources is mainly exposed to PFOA and PFOS via diet and drinking-water.

International, national, and regional authorities have developed increasingly stringent restrictions on occupational exposure, use in consumer products, and guidance values for environmental media and drinking-water. Both PFOA and PFOS are listed in the Stockholm Convention on Persistent Organic Pollutants. Although direct exposure may decline because of such efforts, production and use of PFOA and PFOS precursors may contribute to ongoing exposure.

The Working Group evaluated PFOA as carcinogenic to humans (Group 1) on the basis of sufficient evidence for cancer in experimental animals and strong mechanistic evidence that PFOA exhibits key characteristics of carcinogens in exposed humans. There was limited evidence in humans for cancer of the testis and for renal cell carcinoma. PFOS was evaluated as possibly carcinogenic to humans (Group 2B) on the basis of strong mechanistic evidence. There was limited evidence for cancer in experimental animals and inadequate evidence for cancer in humans for PFOS.

The full scientific assessment will be published as Volume 135 of the IARC Monographs.

Zahm S, Bonde JP, Chiu WA, Hoppin J, Kanno J, Abdallah M, et al.
Carcinogenicity of perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS)
Lancet Oncol, Published online 30 November 2023;
https://doi.org/10.1016/S1470-2045(23)00622-8

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