As urban sprawl moves many households closer to working farms, there is concern that these farm neighbors, specifically pregnant women and children, may be indirectly exposed and at risk from breathing air after applications of pesticides and other farm chemicals.

For a number of years pesticide labels, including those for chlorpyrifos-containing products, have included requirements that applicators take measures to avoid allowing spray to drift from applications to contact people, homes or their yards. Some of these practices were developed as part of industry-wide efforts through a spray drift task force . EPA has recently been developing new methods for assessment and more specific guidance for managing potential exposures to bystanders via inhalation of pesticide spray drift particles and/or pesticide vapor emissions from treated fields.

During July of 2012, the EPA completed a preliminary bystander inhalation exposure assessment using the newly developed methodology as part of its ongoing Registration Review for chlorpyrifos. EPA’s assessment highlighted the importance of providing pesticide applicators with more specific advice as to practical steps they should take to avoiding allowing spray drift to contact people, homes, and yards. To this end, Dow AgroSciences and EPA cooperatively developed revised labeling for chlorpyrifos products that outlines requirements related to spray drift management practices for minimizing bystander exposure. This revised labeling will include establishment of specific setback distances for applicators to observe between the application site and sensitive sites depending on application rate and type of spray equipment. In developing this approach, chlorpyrifos is one of the first pesticide products to provide specific guidance to applicators concerning practical steps for reducing drift for bystander exposures.

Further Resources

"Pesticide Spray and Dust Drift”, Fact Sheet, U.S. Environmental Protection Agency

“Pesticide Issues in the Works: Pesticide Volatilization”, Pesticide Issues in the Works, U.S. Environmental Protection Agency

“Resources on Spray Drift and Its Mitigation”, International Union of Pure and Applied Chemistry

U.S. Spray Drift Task Force:

“Chlorpyrifos Drift Management Q&A”, Dow AgroSciences, 2012 (PDF)