Risk of Illness from Pesticide Drift Greatest for Agricultural Workers, Study Finds

Contact: Fred Blosser, (202) 245-0645

Agricultural workers face the greatest risk of any population for illness from exposure to airborne drifts of pesticides, a new study by researchers from the National Institute for Occupational Safety and Health (NIOSH) and partnering state agencies finds. The paper "Acute pesticide illnesses associated with off-target pesticide drift from agricultural applications — 11 States, 1998–2006," is posted online by Environmental Health Perspectives (EHP) This publication marks the first known comprehensive report of multistate surveillance data on drift-related pesticide poisoning in the U.S., the authors said. Pesticide poisoning can produce any of several symptoms, including eye irritation, skin irritation, dizziness, vomiting, diarrhea, cough, respiratory irritation and pain, chest pain, fatigue, and fever.

Pesticide drift, which is the unintended airborne movement of pesticides away from a target application site as spray, vapor, odor, or other forms, is recognized as a major cause of pesticide exposure affecting people, wildlife, and the environment, the researchers said. The study found that the incidence of "small" drifts – those associated with fewer than five cases of pesticide poisoning per incident – decreased over the period studied. However, the overall incidence of drifts associated with poisonings remained constant, chiefly driven by "large" drifts involving more than five cases per incident. The findings from this new publication should assist authorities in designing appropriate regulatory, enforcement, and education efforts, the researchers said.

"These findings underscore the importance of identifying factors that can result in unintended pesticide exposures, recognizing that any health effects from exposures are cause for concern, and adhering to safe application practices and policies at all times," said NIOSH Director John Howard, M.D. "The study also illustrates the value of Federal and State partnerships in collecting and using data that are vital for informing occupational and public health initiatives."

The study was based on data gathered under NIOSH’s Sentinel Event Notification System for Occupational Risks (SENSOR) program, which provides Federal funding or technical support for occupational health surveillance in 12 states, and California’s Pesticide Illness Surveillance Program (PISP). The study reported that:

• Of 2,945 pesticide poisoning cases associated with pesticide drift that were identified in 11 states during 1996-2008, agricultural workers had the highest incidence rate of drift-related pesticide illness (114.3 cases per million persons). This rate was 145 times greater than the rate for non-agricultural workers. The second highest incidence of drift-related pesticide illness occurred among residents in five agricultural-intensive counties in California, 42.2 cases per million persons. This rate was 69 times higher than the rate in other California counties.
• 53 percent of the 2,945 cases involved non-occupational exposures, and 47 percent represented work-related exposures. However, in proportion to the size of each respective population as a whole, agricultural workers also ranked at higher risk. Additionally, agricultural workers accounted for 73 percent of the occupational exposure cases
• Soil applications with fumigants were responsible for the largest proportion of cases (45 percent) by type of application.
• Aerial applications accounted for 24 percent of the cases.
• 92 percent of the pesticide poisonings resulted in low-severity illnesses which generally resolve without treatment and include such things as eye irritation, upper respiratory irritation, gastric irritation, and dermatitis.
• 14 percent of the cases were children and youths under 15 years of age.

Common factors contributing to pesticide drift included weather conditions such as high winds or temperature inversions, improper seal of the fumigation site such as a tear in the tarp used to cover the site after application or premature removal of a tarp, and carelessness by the applicator, such as flying over houses or failing to turn off a nozzle at the end of a row of crops. The findings show the need to reinforce compliance with regulatory requirements for applications, and suggest that the practice of establishing buffer zones around application sites, as applicators are required now to do, may not be sufficient independent of other safety measures. Other measures may include reducing maximum application rates, using new, validated drift-reduction technologies as they become available, improving training of pesticide applicators, and improving pesticide labels so that directions for use are clear, flexible, practical and enforceable, the researchers said.

NIOSH is the federal agency that conducts research and makes recommendations for preventing work-related injuries, illnesses, and deaths. More information on preventing pesticide-related illness can be found at http://www.cdc.gov/niosh/topics/pesticides/ .

Environmental Health Perspectives is a monthly journal of peer-reviewed research and news published by the U.S. National Institute of Environmental Health Sciences, National Institutes of Health, U.S. Department of Health and Human Services. To view EHP, go to http://ehp03.niehs.nih.gov/home.action. For more information on NIOSH research activities visit the NIOSH website at www.cdc.gov/niosh.