Letter addressed to The Canadian Cancer Society

May 11, 2001


Dr. Barbara Whylie

Director, Cancer Control Policy

Canadian Cancer Society

Suite 200. 10 Alcorn Avenue,

Toronto, Ontario M1V 3Bl


Dear Dr. Whylie,


Re: Domestic Use of Pesticides and Cancer Risk


I am writing to you with regard to the above-noted document that has been published by the Canadian Cancer Society. The following statement is included in this document:


“People should avoid exposure to the following pesticides that IARC (International Agency on Research on Cancer) has concluded are known, probable or possible human carcinogens: … chlorophenoxy herbicides (2,4-D) … .”


IARC will consider only peer-reviewed, published studies, and unlike both U.S. Environmental Protection Agency (“EPA”) and World Health Organization (“WHO”), IARC does not consider the numerous proprietary studies conducted by EPA/GLP qualified laboratories or the EPA reviews (e.g., Data Evaluation Reports) of those studies.


Given this modus operandi, the 2,4-D Task Force has taken the extraordinary step of allowing more than a dozen reviews of its proprietary data to be published in peer-reviewed journals. A number of key epidemiologic cohort studies pertinent to 2,4-D have also recently been published (see below for an example of one such study). The University of Michigan School of Public Health has completed a review of the recent epidemiology and toxicology of 2,4-D and has submitted their review for publication. Once published, IARC will update its evaluation of 2,4-D and we fully expect their conclusions to be in line with those of U.S. EPA and WHO.


In the interim, the Canadian Cancer Society should be aware of the following developments:


  • In January 1997 the U.S. Environmental Protection Agency classified 2,4-D as a “Class D” compound. The “D” classification means that there is insufficient evidence of carcinogenicity in the data package to place the compound in any of the three higher classifications (http://www.24d.org/Rev4.pdf).
  • Furthermore, the U.S. Environmental Protection Agency toxicology profile for 2,4-D identifies the herbicide as non-carcinogenic, non-teratagenic and non-mutagenic (http://www.24d.org/epa_memo.pdf).
  • In addition, the World Health Organization reviewed the full 2,4-D toxicological study package and concluded in their publication, Pesticide Residues in Food – 1996, “there was no evidence of carcinogenicity”.
  • Most recently, a peer-reviewed study of plant workers potentially exposed to 2,4-D over a 50-year period was published in the journal Occupational and Environmental Medicine. The study concluded, “There was no evidence of a causal association between exposure to 2,4-D and mortality due to all causes and total malignant neoplasms. No significant risk due to NHL (Non-Hodgkin’s lymphoma) was found.”


The Industry Task Force II on 2,4-D Research Data is organized under U.S. pesticide law to provide funding for some 270 new research studies required to respond to both the Canadian and U.S. pesticide re-registration programs. These studies, which in accordance with both U.S. and Canadian law, must be done by either Pest Management Regulatory Agency or U.S. EPA Good Laboratory Practice (“GLP”) qualified laboratories. To-date more than thirty such laboratories have been used in Canada and the U.S. All 270 studies have been completed and submitted to the appropriate regulatory authorities.


The 2,4-D Task Force is made up of those companies owning the technical Canadian and U.S. registrations on the active ingredient in 2,4-D herbicides. They are BASF (Germany), Nufarm, Ltd. (Australia), Atanor, S.A. (Argentina), PBI-Gordon Corp. (U.S.A,) and Dow AgroSciences (USA).


Should you have any questions pertaining to 2,4-D, do not hesitate to contact me and I would be most pleased to respond to your queries. I thank you for your interest in this matter.


Sincerely,


Donald L. Page

Executive Director

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