Lisa M. Campbell, James V. Aidala, Susan Hunter Youngren, “EPA Guidance on Pesticide Drift Will Affect Product Registrations,” CPDA Quarterly, June, 2014.

How to address and manage potential risks posed by pesticide “drift” — the unintentional movement of some level of pesticide outside of the intended area of application — has long been a challenging, complex regulatory policy issue. It is difficult to dispute that when applying a pesticide product some small amount may, in some circumstances, move off-site. In other words: “drift happens.” The issue quickly becomes whether, from a risk management perspective, the amount of off-site movement matters. That question is, in turn, heavily dependent on factors specific to the pesticide application at issue, such as the nature of the specific pesticide (e.g., its volatility), the application method used (e.g., aerial or ground application), and climatic conditions. Because many such factors must be considered, the U.S. Environmental Protection Agency (EPA) has found it challenging to devise a “drift policy” or define generally what, if any, level of potential drift is acceptable. This article explores the current situation.