IARC Classifies Six Chemicals For Carcinogenicity

Posted on: September 14, 2018

Carcinogenicityby Caroline Miller, CIH, CSP

Experts from The International Agency for Research on Cancer (IARC) evaluated six chemicals for carcinogenicity. The results were published in The Lancet Oncology, Volume 19 and will be published in Volume 122 of the IARC monographs.  IARC assigned five substances to Group 2B “possibly carcinogenic to humans” and one substance to Group 3 “not classifiable as to its carcinogenicity to humans.”

The substances assigned Group 2B include the following four acrylates:  Methyl acrylate, Ethyl acrylate, 2-Ethylhexyl acrylate, and technical grade Trimethylolpropane triacrylate (TMPTA). Isobutyl nitrite was the fifth chemical to be assigned Group 2B. β-Picoline was the sixth substance evaluated and was assigned Group 3.

The four Group 2B acrylates are chemicals produced in high volumes worldwide to make a variety of products, including acrylic fabrics, paints, resins, plastics, polymers, coatings, and adhesives. IARC noted concern for the acrylates in occupational exposures through inhalation and dermal routes. The general population can be exposed through food and materials containing ethyl acrylate. The general population can be exposed to TMPTA through the use of paints and polishes.

The American Chemistry Council (ACC) criticized the classifications of the four acrylates. In a press release issued by the ACC, the group claims that the Methyl acrylate, Ethyl acrylate, and 2-Ethylhexyl acrylate classifications are “erroneous and misleading.”  The ACC urges IARC revise its scientific practices.

Exposure to Isobutyl nitrite is primarily through recreational drug use.  It is also used as an intermediate in the production of solvents and fuels.

β-Picoline is used for making pesticides and pharmaceuticals, with occupational exposure occurring mainly through inhalation and dermal contact.  It is released from cigarette smoke and it occurs at low concentrations in coffee, beer, and whiskey.

Recommended Action Items

  • Review your inventory of substances to determine if your company uses any of the affected chemicals.
  • Update Globally Harmonized System Classifications and Safety Data Sheets when the affected chemicals are in product composition(s) above specified cutoffs.

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Useful Information

Kromhout, Hans, et al. “Carcinogenicity of Isobutyl Nitrite, β-Picoline, and Some Acrylates.” The Lancet Oncology, vol. 19, no. 8, 2018, pp. 1020–1022., doi:10.1016/s1470-2045(18)30491-1

American Chemistry Council Press Release on Monograph 122


IARC Monographs, Carcinogens, Acrylates, Chemicals


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