Some populations are more vulnerable to pesticide poisoning. In the United States, farmworkers can be exposed via direct spray, drift, spills, direct contact with treated crops or soil, or defective or missing protective equipment. Migrant workers may be at an especially high risk of chronic exposure as over the course of a growing season, they may work at multiple farms, thus increasing their exposure to pesticides. Farmworkers in more permanent positions may receive more safety training and/or more “consistent reinforcement of safety behaviors than seasonal farmworkers or day laborers.” For migrant farmworkers, language barriers and/or education level could be a barrier to understanding posted warning signs, labels and safety warnings located on the pesticides, or understanding any safety training that is provided.