Licensed to cause cancer

This list cites potential pesticide carcinogens from the International Agency for Research on Cancer (IARC), US Environmental Protection Agency (EPA) and the European Union (EU) found in public documents.

Comment
In 1993, PN listed 70 possible carcinogens – now the list has grown to over 160. Many of the pesticides included are obsolete chemicals, which continue to pose global environmental threats (see article above). Other pesticides are still in use, especially those cited by the US EPA. For some pesticides, like DDT, there is agreement about carcinogenic potential, but with many others authorities do not have similar positions.
    The information supplied is taken from a range of sources, and it has not been easy to locate the relevant information. Indeed there are some inconsistencies and inaccuracies between and within the source documents. We invite comment, and hope that this information helps to stimulate international debate on how regulators deal with potentially carcinogenic pesticides. (DB)

Definition of cancer categories
US Environmental Protection Agency 
The US EPA has changed its classification systems in recent years. Some categories have similar definitions:

Weight-of-evidence categories developed during the 1980s
Group B = Probable Human Carcinogen: B1 (limited evidence of carcinogenicity from human epidemiological studies); B2 (sufficient evidence of carcinogenicity from animal studies)
Group C = Possible Human Carcinogen: 

Weight-of-evidence categories developed during the 1990s
Known/Likely available tumour effects and other key data are adequate to demonstrate convincingly a carcinogenic potential for humans.
L1 = Likely at high doses but Not Likely at low doses
L2 = Likely to be carcinogenic to humans available tumour effects and other key data are adequate to demonstrate carcinogenic potential for humans.
S = Cannot be Determined-Suggestive evidence from human or animal data is suggestive of carcinogenicity, but is not sufficient to conclude as to human carcinogenic potential.
Source: Office of Pesticide Programs List of Chemicals Evaluated for Carcinogenic Potential, US EPA, [see details at www.epa.gov/pesticides/carlist/ although list not available on website], August 2000. 

European Union
There is no single EU list available denoting carcinogenic pesticides. EC Directive 67/548 and subsequent amendments provide the classification of dangerous substances, including pesticides. The cancer classifications are:
Category 2 (denoted as R45 on the pesticide label) = May Cause Cancer
Category 3 (denoted as R40 on label) = Possible Risk of Irreversible Effects (Cancer, as cited in table)
Sources: EC Directive 67/548 EEC and subsequent amendments; Chemicals (Hazard Information and Packaging for Supply) [CHIP2] Regulations 1994, Health and Safety Executive, UK.

International Agency for Research on Cancer
Group 1 = Carcinogenic to Humans
Group 2A = Probably Carcinogenic to Humans (limited evidence of carcinogenicity in humans and sufficient evidence in experimental animals).
Group 2B = Possibly Carcinogenic to Humans (limited evidence of carcinogenicity in humans and less than sufficient evidence in experimental animals).
Source: http://193.51.164.11/monoeval/grlist.html [Note: lists cited include many non-pesticides]

For a comprehensive independent source visit PAN North America’s database: www.pesticideinfo.org

[This article first appeared in Pesticides News No.51, March 2001, pages18-19]