Report: 32 million pounds of toxic pesticides sprayed on Ventura County fields from 2015 to 2020


“Ventura County, Calif.,” began a feature story in The Washington Post in August 2015, “is the absolute most desirable place to live in America.”

The article was grounded in county-level rankings from an official government index that combined “six measures of climate, topography, and water area that reflect environmental qualities most people prefer.”

But the Post’s laudatory story didn’t consider another important measure: pesticide exposures. Today, from Oxnard to Ojai, people in Ventura County live, work and go to school next to farm fields sprayed with some of the most toxic pesticides used in agriculture.

Every year, more than 5 million pounds of agricultural pesticides are sprayed in Ventura, just north of Los Angeles, according to an Environmental Working Group analysis of pesticide use data for the county from 2015 to 2020. More than a million pounds of pesticides linked to cancer are used in the county each year, on average.

The county’s farm fields grow a produce-aisle assortment of labor- and pesticide-intensive crops – strawberries, celery, lemons, raspberries and more. And tens of thousands of farmworkers live and work in the county to support Ventura’s annual $2 billion agriculture economy. Much of the county’s population of 846,000 faces the potential health risks associated with pesticides drifting from the fields, whether they work in agriculture-related fields or not.

Policies currently in place to protect public health rely primarily on voluntary compliance from applicators on the amount and type of pesticides used, method and timing of application, and weather conditions, such as wind speed and direction, at the time of pesticide spraying.

And efforts to force better compliance by hiking the fines that state regulators could charge agricultural operations for violating pesticide rules died in the California legislature in 2018. Industry lobbying helped to tank a bill that would have given state officials the power to charge $25,000 for serious rule violations, up from the $5,000 that county agricultural commissioners can currently levy, according to KQED. Defeat of the legislation means one less potential deterrent to overspraying fields.

No state or federal limits have been set restricting the amount of agricultural pesticides allowed in air, so any amount of any single pesticide or pesticide mixture in air, over any period of time, is legal. Although the California Department of Pesticide Regulation performs seasonal air monitoring for pesticides in certain high use areas, the frequency of monitoring and number of monitoring locations do not fully capture the heavy agricultural use in Ventura or the state.

The EWG analysis shows that almost 70 percent of homes in Ventura County are within 2.5 miles of agricultural pesticide use. More than one in four homes are a half-mile or less from fields sprayed with pesticides that have been linked to serious health harms, including cancer, neurotoxicity and harm to development and reproduction.

Thirty-three elementary schools in the county are within a quarter-mile of farming operations where pesticides are sprayed. A 2014 report showed that Ventura had the most schools and most students in the state within a quarter-mile of fields where the greatest amounts of pesticides were applied.

Distance from cropland Residences



Up to 0.25 miles 31,441 33
0.25 to 0.5 miles 43,088 27
0.5 to 1 miles 58,068 17
1 to 1.5 miles 35,240 17
1.5 to 2 miles 19,302 10
2 to 2.5 miles 10,763 6
Total within 2.5 miles 197,902 110

EWG’s in-depth review sorts both crop fields and residential areas in the county, using color-coded areas to show the different hazard levels for every community in the county, with the most hazardous areas facing the greatest potential harm from pesticides. And even in those areas where fewer pesticides may be used, farmworkers and households that neighbor fields could still face elevated exposure to pesticide drift.

EWG scientists parsed reams of data, including more than 760,000 records on county pesticide use from 2015 to 2020 and 265,000 property tax records. We then used this data to produce two maps to inform people living or working in Ventura County about pesticide applications and risks of pesticide exposure.

Ventura county map
Ventura County Pesticide Use

Almost 70 percent of homes in Ventura County are within 2.5 miles of pesticide use areas. More than one in four homes are within a half-mile of pesticide spraying.

The maps provide the first-ever assessment of health concern for Ventura residences based on their proximity to pesticide-sprayed fields, as well as the amount and toxicity of pesticides applied to those fields. By entering a street address, users can obtain extensive information about pesticides used nearby over a six-year period and their potential health effects.

The maps provide a bird’s-eye view of how potentially dangerous pesticide use – still prevalent in the agricultural industry – might be affecting community health across the county. EWG’s maps provide crucial information about the types and amounts of pesticides used on fields near homes, schools and workplaces, and the health concerns from those pesticides.

EWG’s analysis underscores the need for conventional farming to shift away from these pesticides and embrace alternative pest management practices. Both the state and federal government agencies also need to step up and get the most harmful agricultural chemicals off the market.

Mapping the risks of pesticide exposures in Ventura County

Pesticide exposure can occur from working with pesticides directly and from exposure to pesticide drift from fields through the air, airborne dust from farms, and pesticide deposit in dust on carpets, floors and other materials in houses and buildings near pesticide use areas. Pesticide spraying can also contaminate drinking water sources.

EWG scientists mapped pesticide use data across the county and analyzed the combined health concerns from those pesticides for farmworkers, children and people of all ages living near agricultural fields.

Epidemiological studies conducted in California found that living near pesticide spraying is linked to harm to the respiratory system, increased risk of cancer and harm to the developing child, such as low birth weight and reduced IQ.

These health risks are greatest for farmworkers and their families, who experience the highest exposures to pesticides sprayed on cropland. But families across Ventura County, all the way out to Ojai, are also at risk if their homes are near farming operations where these pesticides are sprayed.

In Ojai, which is not located in the most agriculture-intensive area of Ventura County, pesticides have been found to drift from adjacent farms onto residents’ property, and EWG’s analysis shows that more than eight thousand spray events occurred within 2.5 miles of the town from 2015 to 2020. 

Local activists from Ojai, as well as farmworker justice advocates from other parts of Ventura County, are pushing local and state officials to take action to limit pesticide exposure from farming operations.

EWG’s analysis identified 61 pesticides sprayed in Ventura County that are linked to cancer, 77 pesticides that may harm the nervous system, 75 pesticides that may interfere with the hormonal system, 46 pesticides that may cause harm to the thyroid, and 88 that alter development or reproduction in laboratory animals.

Pesticide-use records show that more than four million pounds of 26 pesticides that harm the respiratory system are used on average each year in the county. The fumigants chloropicrin, metam-sodium and 1,3-dichlorpropene, as well as petroleum distillates and mineral oil, are used in the highest amounts.

1,3-dichlorpropene also increases the risk of cancer, and the California Department of Pesticide Regulations recently determined that more mitigation measures are needed to protect individuals from drift of this pesticide.

Ventura county pesticide carcinogen chart

Pesticide applications vary across Ventura County.

Between 2015 and 2020, according to records farm operators are required to submit to the local agriculture commissioner, more than 360,000 pesticide spray events, accounting for more than 17 million pounds of pesticides, occurred within 2.5 miles of the densely populated town of Oxnard. The town is home to roughly 208,000 people.


Average pesticide applications per year



Land area (square miles)

Number of pesticide spray events

Total pounds of pesticides applied

Pesticides applied by land area (pounds per square mile)













San Buenaventura






Port Hueneme






Santa Paula












Thousand Oaks


















Simi Valley






The number of pesticide spray events and corresponding pounds of pesticides applied are reported as a yearly average based on data from 2015 through 2020 for the area of the city as well as 2.5 miles outside of the city borders. Some pesticide spray events are included in the summary statistics for more than one city in this table.

Farmworkers and their families at greatest risk

Farmworkers experience higher exposures to pesticides, compared to the general public. A recent study from Washington state, as well as research published by the Centers for Disease Control and Prevention, reported that farmworkers are most exposed to pesticide drift and have the highest rate of pesticide poisoning from drift exposure.

House Farm Workers, a nonprofit organization based in Ventura County, reports there are more than 40,000 farmworkers in the county. These numbers are approximate, since data on where farmworkers live and their housing conditions have not been collected since 2002. The previous study reported overcrowding and poor living conditions, such as lack of adequate bathroom and kitchen facilities.

According to a report by California Research Bureau, 92 percent of farmworkers in California are Latino. Migrant Latino farmworker population experiences a disparate burden of pesticide exposure and poor working and living conditions, low income, and language and social barriers, among other psychosocial stressors, making this an issue of environmental justice.

Reducing pesticide exposures to improve public health

Neither the state of California nor the U.S. Environmental Protection Agency has set health-protective, enforceable standards for the amount of individual pesticides, let alone mixtures of them, allowed in air. So it is difficult to identify the precise risks pesticide exposure from air pose to people who live and work in these communities.

Additionally, the limited amount of air monitoring for pesticides done in California indicates that some pesticides can travel miles from their application area. And research has shown that health harms from pesticides, including childhood cancers, may occur up to 2.5 miles away.

There are some steps anyone can take to reduce pesticide exposure. People living or working near pesticide spraying can remove shoes before entering the home, change and wash clothes soon after returning home and vacuum frequently to remove dust.

At the federal level, the EPA should take action to ban or restrict some of the most toxic pesticides used in Ventura and across the country, such as Dacthal, iprodione and paraquat, as well as the neurotoxic organophosphates. Among the 50 most used pesticides in Ventura, several belong to the class known as organophosphates (malathion, acephate, naled and bensulide). Organophosphates are especially toxic to the nervous system.

The EPA has this authority, and in August 2021 it took the step of announcing a ban on all uses on food crops of the potent neurotoxic organophosphate pesticide chlorpyrifos.

At the state level, the California Department of Pesticides is currently developing a state-wide pesticide notification system to alert individuals when and where pesticides will be sprayed, so they can take further precautions to protect their health. And a proposed bill in California to increase pesticide registration fees based on pesticide toxicity could fund additional pesticide research and enforcement programs.

Ultimately, conventional agriculture’s heavy reliance on pesticides, especially those used on fields near where people live, work and go to school, should be reduced through other pest management techniques. These are the actions needed to protect the health of agricultural workers, their families and communities located near agricultural fields that cover more than 24 million acres in California, according to the U.S. Department of Agriculture.


For its analysis, EWG used pesticide spraying data from 2015 through 2020, received through a public records request from the Ventura County agricultural commissioner’s office.

EWG scientists then reviewed the nearly 400 active pesticide ingredients used 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.

Residence locations were taken from land ownership parcel data for 2020, available from the county tax assessor.

Please see the full methodology for more details. 


EWG staff who contributed to the production of this report include:   

Chris Campbell, VP for Information Technology
Anne Schechinger, Midwest Director
Anthony Lacey, Editor-in-Chief
Ketura Persellin, Editor
Rob Coleman, Project Manager
Soren Rundquist (former Director of Spatial Analysis at EWG)
Sean Perrone-Gray (former Senior Database Programmer at EWG)

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Common Questions

Why did EWG develop this map?

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.

How do I use this map?

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.

How is the map of “Residential areas” different from the map of “Fields”?

Map visitors can assess pesticide use and health concerns through two map displays:

  • Fields, showing the areas where pesticides are applied.
  • Residential areas, showing groups of residences and schools, highlighted in purple, that are within a 2.5-mile radius of fields where pesticides are applied.

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.

What do the colors in the map mean?

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.

How specific is the application location for pesticides?

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.

How did you determine the pesticides’ health harms?

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.

Why did you choose Ventura County?

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.

What about organic fields? Are pesticides used on them, and are those pesticides less hazardous?

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.

Our family lives in the “red zone.” Should I be worried, and what can we do to protect our health?

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:

  • If you see pesticide application occurring, make sure to close windows and bring children and pets inside.
  • People living or working near pesticide spraying can remove shoes before entering the home, use a doormat in the entryway, change and wash clothes soon after returning home and vacuum frequently to remove dust.
  • Report pesticide drift events to the local agricultural commissioner’s office.

What is a safe distance from a field where pesticides are sprayed?

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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