When evaluating a pesticide's environmental risks, including those involving bees, we look at a wide range of data on the environmental fate and toxicological effects of a compound The process of comparing toxicity information and the amount of the pesticide a given organism may be exposed to in the environment is called risk assessment.
Risk assessments try to predict the effects from using a pesticide. A risk assessment compares the predicted exposure an organism will receive, to the toxic effects that compound produces at different exposure levels, (the amount of exposure to a pesticide often determines an organisms toxicological response). Thus, the risk assessor's job is to determine the relationship between possible exposures to a pesticide and the potential for harmful effects as a result.
If a pesticide can be used in a way that minimizes exposure to levels below the point at which there are no effects, EPA concludes that the pesticide is not likely to harm non-target organisms, including bees. On the other hand, if the ecosystem exposure levels are suspected or known to be high enough to produce problems, we will then work to better understand the factors that contribute to the risk. Then we introduce measures to manage the risks to acceptable levels, such as limiting where and when the pesticide can be used.
If the risk assessment indicates a high likelihood of hazard to bees or other non-target organisms, we may require additional testing, require that the pesticide be applied only by specially-trained people or in certain circumstances, or decide not to allow its use at all. In accordance with federal law, decisions on risk reduction measures are based on a consideration of both pesticide risks and benefits.
EPA only registers pesticides that are known to be harmful to bees if the approved uses involve potential bee exposures below our level of concern. For example, many of the labels of neonicotinoid pesticides, which are known to be toxic to bees, stipulate that the products may not be used if nearby crops or weeds are in bloom and bees are visiting the treatment area. By reducing or eliminating the possibility for exposure, we allow growers and other pesticide users to realize the benefits of responsible pesticide use while avoiding toxic exposure to bees.