A thorny issue amongst scientists, health-advocacy groups and the public, world experts who gathered in Toronto for a two-day conference hosted by the Canadian Cancer Society, concede that it is still not certain, whether pesticides used by farmers on growing crops, cause cancer.

Aaron Blair, an occupational pesticide exposure expert at the U. S. National Cancer Institute says, studies conducted on lab animals exposed to various bug, weed and rodent killers show, certain pesticides appear to cause some types of cancer. But, it is difficult to figure out whether both synthetic and naturally occurring chemicals have the same effect on people. However, some studies do show farmers and populations having contact with pesticides, to have an apparent excess of certain cancer, such as lymphomas.

Greg Hannam, a representative of AgCare - the group representing farm groups on environmental issues, was also present at the gathering of experts, who are trying to come up with a policy for the use of farm chemicals. Though, opposed to cosmetic use of pesticides, none of them were able to come to any conclusion or consensus regarding pesticides and farm products.

To sum it up, Blair says studies on humans; should look for a possible association between exposure to a chemical substance and a health outcome like cancer, so that solid evidence against use of pesticides and cancer could be arrived at.