Harmful Pesticide Use Down Since CA Ban, More Work Needed to Protect At-Risk Communities

Oakland, CA — A new study published in BMC Public Health has found that the use of chlorpyrifos — an organophosphate (OP) pesticide commonly used in agriculture that has been linked to many negative health conditions when pregnant people are exposed to it — sharply dropped in California following a statewide ban in 2020, and overall OP pesticide use more than halved. However, OP pesticides were still applied near tens of thousands of pregnant Californians in 2021, meaning additional policies are needed to protect pregnant Californians from harmful chemicals. The study was led in collaboration with Tracking California, a program of the Public Health Institute, an independent public health consultant and researchers from the University of California, Berkeley.

OP pesticides, like chlorpyrifos, are broad-spectrum insecticides widely used in agriculture, primarily on fruits, vegetables, grains and fiber crops. OP pesticides are neurotoxicants that inhibit the neurotransmitter acetylcholinesterase, and early life exposure to some OP pesticides has been linked to reduced IQ, ADHD, autism, changes to brain morphology and cerebral palsy. For this reason, it is recommended that pregnant people avoid contact with OP pesticides.

Tracking California, the State’s CDC-funded environmental health surveillance program, utilized its state-of-the-art Pesticide Linkage Service to assess how pesticide use patterns have changed since California banned the use of chlorpyrifos in 2020. The study found that following the state’s ban:

• Chlorpyrifos use dropped by 99%.
• The use of all OP pesticides declined by 54%, with decreases seen in 18 of the other 19 OP pesticides examined.
• The San Joaquin Valley, which had been the State’s largest user of chlorpyrifos, benefited the most, with total OP pesticide use decreasing by 74%.
• Benefits from this ban were not shared equally across California. The Central Coast growing region, home to much of the country’s strawberry and lettuce supply, saw no change in OP pesticide use.
• Monterey County had a 26% increase in OP pesticide use over this same time period.

The analysis also examined over 390,000 birth records to understand where expecting parents may be at greater risk of OP pesticide exposure. The analysis found that 7.5%, or 29,386, of pregnant people statewide lived within 1 kilometer of any OP pesticide use. In 9 counties, that jumped to over 20%, and in Monterey County, it was over 50%. Statewide, pregnant Hispanic people were most likely to live near OP pesticide use. These findings show that additional regulatory changes are needed to limit the use of harmful chemicals and protect children’s brain development.

The study was led by Miriam Rotkin-Ellman, an independent public health researcher, with support from Catherine Carpenter, Maxwell J. Richardson and Paul B. English of PHI’s Tracking California, and Robert B. Gunier and Kim G. Harley with the University of California, Berkeley.

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About Tracking California

Tracking California works to make environmental health data and information publicly available through the development of a web-based data query system, state-of-the-art data displays, and innovative web tools and services. Tracking California is a program of the Public Health Institute, in partnership with the California Department of Public Health and the Centers for Disease Control’s (CDC) National Environmental Public Health Tracking Program.

Tracking California is a program of the Public Health Institute, an independent nonprofit organization, dedicated to promoting health, well-being and quality of life for people throughout California, across the nation and around the world.