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Background: What is pesticide drift?

Helicopter spraying pesticides over field and water

Pesticide drift is the airborne movement of pesticides, away from the intended target. Pesticide drift can affect everyone, both urban and rural communities, by having negative effects on human health and the environment. There are two types of drift, spray drift and post-application drift. Spray drift occurs during and soon after a pesticide application, while post-application drift occurs after application is complete, for hours and even days later.

Gases, droplets and dust particles rise into the air and can be driven miles from application sites by winds, resulting in widespread toxic air pollution. Drift also occurs when pesticides are applied in homes and gardens for fumigations.

Pesticide Drift in California

Pesticide drift is particularly a problem in California because of the vast amount of use here—around 200 million pounds of active ingredients each year. More than 90% of pesticides used in the state—products used as sprays, dusts, or gaseous fumigants—are prone to drift. Many drift off-site for days or weeks after the application because of their high volatility or evaporation into the air.

Pesticides and Human Health

Two types of poisoning can result from exposure to pesticide drift: acute and chronic. Acute poisonings cause symptoms soon after the exposure occurs. Symptoms of acute poisoning are usually obvious, such as eye, skin and respiratory irritation, asthma attacks, nausea, vomiting, headache, tremors, numbness and more. Symptoms may mimic those of flue, colds and headaches. Farmworkers, their families, farmers and "fence-line" communities are on the front lines for this type of poisoning.

Chronic poisoning is a result of pesticide exposures, often at low levels, over a long period of time. Like secondhand cigarette smoke, chronic exposures to drifting pesticides can have long-term health effects, even though people may experience few or no symptoms until long after their exposure.

People affected by pesticide drift

The developing fetus, infants, and young children are the most vulnerable to both acute and chronic health effects from drift.

Both urban and rural communities can be affected by drift. Farmworkers are most at risk of pesticide drift exposure because of their proximity to and involvement with pesticide applications. While it is illegal to spray a field occupied by workers, no law prevents spraying a field located beside another with workers present.

Organic farmers suffer economic damage when contamination from drift lengthens the time required to obtain organic certification, disqualifies produce for the certified organic label and disrupts beneficial insect populations. Even conventional farmers can sometimes lose part of their crop because of drift.

Residents in suburbs on the agricultural-urban interface and people living or working in agricultural communities have daily exposure to multiple pesticides from post-application drift of pesticides.

Urban residents are exposed to drift from pesticide applications in neighboring homes and gardens. Structural fumigations can result in pesticide drift. City residents can also be exposed to low levels of pesticides in air through long-range drift from agricultural areas.