This map can be used for public education, identification of high-risk areas, and the development of policy and research priorities to reduce human health harms from pesticides. The map provides information on the types and amounts of pesticide used on fields near residents’ homes and the health harms associated with those pesticides.
For people who work, live or go to school near agricultural fields, exposure to pesticide drift can increase the risk of respiratory and skin irritation and of long-term harms such as cancer, damage to the brain and nervous system, and low birth weight. The EWG map summarizes the available data about those potential risks.
A map visitor can type a street address or locality, such as a school name, into the search bar on the upper right corner of the map to focus on that area. They can then click on a map area to see pesticide use information, including the list of 10 pesticides applied in greatest volume in that area and the health concerns with each pesticide, as well as information on field ownership. (Pesticide use data are reported based on township sections. A section is about one square mile.)
Clicking the circular “Info” button at the bottom left corner of the map brings up information about the map and key findings from the data analysis. The map and accompanying report are also available in Spanish.
Map visitors can assess pesticide use and health concerns through two map displays:
In the “Residential areas” view, pesticide use and toxicity information are presented for all pesticide use areas within 2.5 miles of a residential area. This information highlights the cumulative impact of living near multiple fields. The “Fields” view displays data for a section area, approximately one square mile.
The map colors – yellow, orange and red – reflect the amount of pesticides applied in an area and their toxicity, with red representing the highest level of use and/or toxicity. The total amount and toxicity of pesticides is represented on a sliding scale of overall impact, based on percentiles between lowest and highest pesticide impact. Clicking on the field or residential area will display more detailed information on pesticides of greatest concern.
To determine the hazard score in the “Residential areas” tab of the map, EWG scientists also considered the proximity of a residence to pesticide applications. Areas are marked red if there is a large amount of pesticides applied to that area, if they are highly toxic, or if they are close to fields. Areas marked yellow have the lowest 50th percentile of calculated hazard scores.
There can be differences in hazard level among fields grouped in the same color.
The full methodology provides more details about how the hazard score was calculated.
Pesticide use data are reported based on township sections of about one square mile, and sections may contain agricultural and nonagricultural land. Crop maps were overlaid with images of land sections to enable the map visitor to identify the locations of pesticide application in each township more accurately.
Every crop field for which most of the land fell within a single section was assigned the pesticide use characteristics reported for that section. Pesticide application locations reflect overall usage in a section, not field-specific pesticide applications.
To assign specific toxicological impacts to individual pesticides, EWG scientists evaluated published assessments by authoritative health agencies and toxicity information in peer-reviewed scientific literature.
EWG included the following chronic and acute health effects: cancer, harm to the brain, hormone disruption, thyroid toxicity, harm to developing children, harm to the reproductive system and harm to the immune system, including asthma and respiratory irritation.
Ventura has a high density of homes and schools near agricultural fields. Thirty-three elementary schools are within a quarter-mile of pesticide spraying areas. Almost three out of four homes in Ventura are within 2.5 miles of pesticide use areas and more than one in four homes are within a half-mile of pesticide spraying.
Yes, pesticides are often used on certified organic fields. But those pesticides are far less toxic than many of the chemicals allowed for use in conventional farming. To earn organic certification, farmers can choose from a very short list of pesticide active ingredients. Organic pesticides are often derived from natural sources, including compounds such as sulfur- and copper-based pesticides. According to certifying agent California Certified Organic Farmers:
Organic farmers are only allowed to use biological or botanical pesticides such as neem- and citrus-based materials, and synthetic materials included on the National List of Allowed and Prohibited Substances. Materials on the National List are evaluated by the National Organic Standards Board, which recommends addition and removal of materials based on criteria including lack of a natural alternative; no adverse impacts on the environment during the material’s manufacture, use, or disposal; and the material not contributing to contamination of crops, soil, or water.
The data collected on pesticide use in California do not indicate whether the location where they were applied was an organic field, which makes it difficult to identify the areas that are used for organic agriculture. Both organic and conventional agriculture fields are included in the EWG map, with no distinction between them. In Ventura in 2020, organic agriculture accounts for about 10 percent of crop value, and 3 percent of crop acreage.
A recent study of 9,000 fields in Kern County, Calif., a major agricultural production county, found that for organic farms, the likelihood of pesticide use is 30 percent less than for non- conventional fields. According to the National Pesticide Information Center, “most of the natural pesticides used in organic production are exempt from the requirement for a tolerance because they are so low in toxicity.” A tolerance is the maximum allowable limit of a pesticide allowed in food, set by the federal Environmental Protection Agency.
Several factors determine which zones are red, including proximity to pesticide applications, the large amount of pesticides applied, and high pesticide toxicity. People may be at greater risk of pesticide exposure if they live in a red zone.
There are many ways people can protect their health by reducing pesticide exposure:
The closer a person, home or school is to pesticide applications, the greater the risk of harm from pesticide exposure or pesticide drift, especially from acute harm, like skin and respiratory irritation or dizziness and drowsiness. Importantly, certain variables, such as wind speed and wind direction, can affect the risk of pesticide drift and exposure significantly.
California restricts daytime pesticide application within a quarter-mile of schools.
But pesticide air monitoring has shown some pesticides can travel miles from the application site, and recent epidemiological evidence suggests that health harms such as pediatric cancers may be associated with pesticide applications up to 2.5 miles away.
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