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Talc and Acrylonitrile

IARC Monographs on the Identification of Carcinogenic Hazards to Humans Volume 136

IARC

2025

ISBN-13

978-92-832-0293-6

Other languages

No other languages


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This volume of the IARC Monographs provides evaluations of the carcinogenicity of talc and acrylonitrile.

Talc was defined as a mineral (natural) or synthetic product, a hydrated magnesium silicate, that exists in both lamellar and fibrous (including asbestiform) types. Asbestiform talc is not asbestos; however, asbestos is present in some talc deposits and has been shown to contaminate some talc products. A mineral with a high production volume, talc is used in plastics, ceramics, paint, paper, roofing materials, rubber products, animal feed, food, fertilizers, cosmetics, and pharmaceuticals. It is also used in clinical settings for pleurodesis. Occupational exposure to talc dust occurs predominantly during mining and milling, mainly via inhalation, but can also occur among workers in downstream industries. The general population may be exposed via talc-based consumer products, and pathways of exposure include ingestion, inhalation, and dermal contact, including via the perineum.

Acrylonitrile is a chemical with a high production volume that is mostly used as a monomer to prepare polymers for the manufacture of fibres for textiles (acrylic fibres) used in clothing and carpets and other textiles, resins, synthetic rubber, and plastics. Occupational exposure occurs mainly in production industries via inhalation and dermal routes. The general population can be exposed to acrylonitrile via cigarette smoking, air pollution, and contact with contaminated consumer products.

An IARC Monographs Working Group reviewed evidence from epidemiological studies, cancer bioassays in experimental animals, and mechanistic studies to assess the carcinogenic hazard to humans of exposure to these agents and concluded that:

  • Talc is probably carcinogenic to humans (Group 2A);
  • Acrylonitrile is carcinogenic to humans (Group 1).

ANNEX 1. Supplementary material for Section 1, Exposure Characterization

These supplementary tables are available online only.

Talc

The following tables were produced in draft form by the Working Group and were subsequently fact-checked, but not edited:

 
 
 
 
 

Acrylonitrile

Table S1.6 Occupational area air monitoring data for acrylonitrile, by industry or type of workplace

Table S1.7 Occupational personal air monitoring data for acrylonitrile, by production industry

The following tables were produced in draft form by the Working Group and were subsequently fact-checked, but not edited:

Table S1.12 Exposure assessment review and critique for epidemiological studies on cancer in humans exposed to acrylonitrile

Table S1.13 Exposure assessment review and critique for mechanistic studies in humans exposed to acrylonitrile

 

ANNEX 2. Quantitative bias analysis for exposure misclassification for the effects of ever versus never use of talc on ovarian cancer

 

ANNEX 3. Supplementary material for Section 4. Mechanistic Evidence

These supplementary online-only tables contain summaries of the findings (including the assay name, the corresponding key characteristic, the resulting “hit calls” both positive and negative, and any reported caution flags) for those chemicals evaluated in the present volume that have been tested in high-throughput screening assays performed by the United States Environmental Protection Agency (US EPA) and the United States National Institutes of Health. The results were generated by the Working Group using the software “kc-hits” (key characteristics of carcinogens – high-throughput screening discovery tool) available from https://gitlab.com/i1650/kc-hits.git (Reisfeld et al., 2022), using the US EPA Toxicity Forecaster (ToxCast) assay data and the curated mapping of key characteristics to assays available at the time of the evaluations performed for IARC Monographs Volume 136. Data were available for acrylonitrile.

Please report any errors to imo@iarc.who.int.

1. Acrylonitrile: ToxCast/Tox21 assay results mapped to the key characteristics of carcinogens

Reference

Reisfeld B, de Conti A, El Ghissassi F, Benbrahim-Tallaa L, Gwinn W, Grosse Y, et al. (2022). kc-hits: a tool to aid in the evaluation and classification of chemical carcinogens. Bioinformatics. 38(10):2961–2. https://doi.org/10.1093/bioinformatics/btac189 PMID:35561175