Neil E. Pearce, London School of Hygiene and Tropical Medicine
Aaron Blair, National Cancer Institute (NCI)
Paolo Vineis, Imperial College
Wolfgang Ahrens, BIPS
Aage Andersom, Cancer Registry of Norway
Josep M. Anto, Universitat Pompeu Fabra
Bruce K. Armstrong, The University of Sydney and Sax Institute
Andrea A. Baccarelli, Harvard T.H. Chan School of Public Health
Frederick A. Beland, National Center for Toxicological Research
Amy Berrington, National Cancer Institute (NCI)
Pier Alberto Bertazzi, University of Milan
Linda S. Birnbaum, NCI, NIH, DHHS, Research Triangle Park, North Carolina
Ross C. Brownson, Washington University, St. Louis
John R. Bucher, National Institute of Environmental Health Sciences (NIEHS)
Kenneth P. Cantor, KP Cantor Environmental LLC
Elisabeth Cardis, CREAL, IMIM, and CIBERESP
John W. Cherrie, Institute of Occupational Medicine, Edinburgh
David C. Christiani, Harvard T.H. Chan School of Public Health
Pierluigi Cocco, University of Cagliari-Monserrato
David Coggon, University of Southampton
Pietro Comba, “Charles Darwin” Sapienza Rome University
Paul A. Demers, Occupational Cancer Research Centre, Cancer Care Ontario
John M. Dement, Duke University
Jeroen Douwes, Massey University
Ellen A. Eisen, University of California, Berkeley
Lawrence S. Engel, University of North Carolina at Chapel Hill
Richard A. Fenske, University of Washington School of Public Health, Seattle
Lora E. Fleming, University of Exeter Medical School
Tony Fletcher, London School of Hygiene and Tropical Medicine
Elizabeth Fontham, Louisiana State University School of Public Health
Francesco Forastiere, Lazio Regional Health Service
Rainer Frentzel-Beyme, Universität Bremen
Lin Fritschi, Curtin University
Michel Gerin, Universite de Montreal
Marcel Goldberg, Inserm UMS 011
Philippe Grandjean, University of Southern Denmark
Tom K. Grimsrud, Cancer Registry of NorwayFollow
Per Gustavsson, Karolinska Institutet
Andy Haines, London School of Hygiene and Tropical Medicine
Patricia Hartge, National Cancer Institute (NCI)
Johnni Hansen, Danish Cancer Society Research Center
Michael Hauptmann, Netherlands Cancer Institute
Dick Heederik, Utrecht University
Kari Hemminki, German Cancer Research Center (DKFZ)
Denis Hemon, Paris Descartes University
Irva Hertz-Picciotto, University of California, Davis
Jane A. Hoppin, North Carolina State University
James Huff, NIEHS, NIH, DHHS, Research Triangle Park, North Carolina
Bengt Jarvholm, Umea University
Daehee Kang, Seoul National University
Margaret R. Karagas, Dartmouth College

Document Type


Publication Date


Publication Title

Environmental Health Perspectives


Geisel School of Medicine


Background: Recently, the International Agency for Research on Cancer (IARC) Programme for the Evaluation of Carcinogenic Risks to Humans has been criticized for several of its evaluations, and also for the approach used to perform these evaluations. Some critics have claimed that failures of IARC Working Groups to recognize study weaknesses and biases of Working Group members have led to inappropriate classification of a number of agents as carcinogenic to humans.

Objectives: The authors of this Commentary are scientists from various disciplines relevant to the identification and hazard evaluation of human carcinogens. We examined criticisms of the IARC classification process to determine the validity of these concerns. Here, we present the results of that examination, review the history of IARC evaluations, and describe how the IARC evaluations are performed.

Discussion: We concluded that these recent criticisms are unconvincing. The procedures employed by IARC to assemble Working Groups of scientists from the various disciplines and the techniques followed to review the literature and perform hazard assessment of various agents provide a balanced evaluation and an appropriate indication of the weight of the evidence. Some disagreement by individual scientists to some evaluations is not evidence of process failure. The review process has been modified over time and will undoubtedly be altered in the future to improve the process. Any process can in theory be improved, and we would support continued review and improvement of the IARC processes. This does not mean, however, that the current procedures are flawed.

Conclusions: The IARC Monographs have made, and continue to make, major contributions to the scientific underpinning for societal actions to improve the public’s health.