Key findings
People who work on, live near, or go to school close by farms where pesticides are used can be at risk of acute illness, including respiratory and skin irritation, and severe chronic health effects such as cancer, brain damage and low birth weight. This map aims to inform residents and farmworkers in California’s Ventura County about those potential risks.
The map provides crucial information on the types and amounts of pesticides used on fields near residents’ homes and the adverse health effects associated with those pesticides. This map can be used for education, identification of high-risk areas, and generation of policy and research priorities to reduce human health harms from pesticides.
Map visitors can assess pesticide use and health concerns through two map modes:
EWG used pesticide application data from 2015 through 2020, supplied by the Ventura County Agricultural Commissioner. Pesticide use record keeping and reporting in California is required by law as part of the California Pesticide Use Reporting Program, established in 1990.
Fields were sorted into categories of concern based on the amounts and toxicity of pesticides applied. Pesticide application amounts, in pounds, were adjusted by the pesticide toxicity and then added together over the six-year period.
Residence locations were taken from 2020 parcel data about the legal boundaries of land ownership in the county, administered by the county assessor. The data for the amount and toxicity of pesticides used nearby was then adjusted based on how close a residence was to a field. If the residence was near multiple fields, the data from multiple fields was averaged.
EWG scientists reviewed the almost 400 active pesticide ingredients used on fields in Ventura County for acute and chronic health effects including cancer, neurotoxicity, endocrine disruption, reproductive and developmental toxicity, thyroid toxicity, immunotoxicity, asthma and respiratory irritation. More than 15 data sources were used to assess pesticide toxicity, including comprehensive assessments performed by government agencies and peer-reviewed literature, as well as predictive approaches based on pesticide toxicity in cells.
The severity of health effects, reliability of data sources and strength of the association were all considered in the toxicity evaluation. All health effects were combined to calculate an overall pesticide toxicity score that was used to adjust the pounds applied.
A full methodology and list of data sources can be found here.