Pesticides are a group of many different chemicals. The International Agency for Research on Cancer (IARC), the US Environmental Protection Agency and the National Toxicology Program classify pesticides according to their link with cancer. Find out more about how cancer-causing substances are classified.
IARC has classified the pesticide lindane, as well as pesticides containing arsenic, as known carcinogens. The use of arsenic in pesticides is restricted in Canada, although arsenic is found in some pesticides used to preserve wood for non-residential purposes. Lindane is prohibited for use as a pesticide in Canada. In the past, lindane was used as a treatment for head lice, but products containing lindane for head lice treatment are no longer available in the Canadian market. If you find any products for lice treatment containing lindane in your home, talk to your local pharmacist about a safe way to dispose of the product.
Research does not show a definite link between most of the pesticides studied and human cancer, but it does suggest a possible connection with cancers such as non-Hodgkin lymphoma, multiple myeloma, chronic lymphocytic leukemia, and prostate, testicular, pancreatic, lung and non-melanoma skin cancers. Studies of pesticides and childhood cancer show a possible connection with leukemia, and non-Hodgkin lymphoma. A possible link between childhood brain cancer and parents’ exposure to pesticides at work has been studied, but there is not enough evidence to make a conclusion.
Farmers exposed to higher levels of pesticides
Studies have been done of people who apply pesticides on farms to find out how many of these people get cancer and how many die from it. The results suggest that this group may have a slightly higher risk than the average person of developing non-Hodgkin lymphoma, leukemia, multiple myeloma, and cancers of the prostate and brain.
One study from the US Agricultural Health Study found that men who applied pesticides had higher rates of prostate cancer compared with the average man. Also, another study suggested that people who are exposed to pesticides at work, such as farmers and farm workers, may be at a higher risk of myeloid leukemias, particularly acute myelogenous leukemia.
More research needed
Current research on pesticides doesn’t give us all the information we need:
- There is only a small amount of research about exposure to pesticides in Canada – information is often from other countries that may have different exposure patterns and types of pesticides.
- The lack of accurate information about exposure and health outcomes makes it hard to study the link between pesticides and cancer.
- Changes over time in the types of pesticides available and in their use can make it hard to understand the health risks of current products.