Drift is a concern only if proper precautions are not taken by the applicator.

Two types of drift may cause chemicals to move off target. Particle drift occurs when the wind scatters small spray droplets off the intended application site. Vapor drift occurs when chemicals evaporate and move with air currents to other sites. Vapor drift is not common among specialty products. In either case, an applicator should be aware of wind conditions that could cause drift..

Source: pestfacts.org