Backgrounder: Neonicotinoid Pesticides and the Proposed Special Review Decisions for Clothianidin and Thiamethoxam

August 2018

Neonicotinoids are a class of pesticides that are used to control insects on a variety of agricultural crops, including seed treatments, and on turf and ornamental plants. Although primarily used in agriculture, neonicotinoids can also be used for other applications such as controlling cockroaches and ants.

In November 2016, Health Canada published a proposed re-evaluation decision for the neonicotinoid, imidacloprid. Health Canada scientists routinely re-examine pesticides that are registered in Canada to ensure they continue to meet modern safety standards for human health and environmental protection. 

The re-evaluation of imidacloprid identified that it was being measured at levels that are harmful to certain aquatic insect populations, a critical food source for fish, birds and other animals. The Department proposed to phase out most uses of imidacloprid over the course of three to five years, due to these concerns. This affected mostly fruit and vegetable producers.

Based on the findings of the imidacloprid re-evaluation, Health Canada also initiated special reviews for two other neonicotinoid pesticides being detected frequently in aquatic environments. A special review is initiated when there are reasonable grounds to believe that the health or environmental risks, or the value (including effectiveness), of a pesticide is unacceptable.

In the cases of clothianidin and thiamethoxam, special reviews were initiated based on concerns identified by Health Canada from available scientific information that these two pesticides are frequently being detected in aquatic environments in Canada at concentrations that may pose a risk to aquatic insects.

The Department is committed to keeping Canadians informed about this issue and will provide updates as new information becomes available.