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State Strengthens Use Restrictions of Pesticide 1,3-D to Protect Public Health

DPR logo
Julie Henderson
California state seal
Gavin Newsom

Yana Garcia
Secretary for Environmental Protection

Leia Bailey, Communications Director
(916) 445-3974 |
November 15, 2022

En Español

SACRAMENTO – Today, the California Department of Pesticide Regulation introduced proposed regulations to protect Californians from potential exposure to 1,3- dichloropropene (1,3-D), a hazardous pesticide.

The proposed regulations would strengthen restrictions on use and significantly reduce potential residential and non-occupational bystander exposure to one of the most highly used agricultural pesticides in California, 1,3-D. The pesticide 1,3-D has been linked to potential acute and cancer health effects at certain levels of exposure.

"Reducing human health risks from 1,3-D exposure is a priority for the state," said DPR Director, Julie Henderson. "Taking action to strengthen restrictions on the use of 1,3-D to lower those risks is core to our mission of protecting human health and the environment."

1,3-D is used by farmers to kill a variety of soil-borne pests, including microscopic worms called nematodes. The pesticide is a fumigant that is injected into soil prior to planting crops such as carrots, strawberries and sweet potatoes, and is also applied prior to planting almond and walnut trees, raspberries and grape vines.

DPR’s proposed regulations require the use of totally impermeable film (TIF) tarpaulins or alternate mitigation measures that provide a comparable degree of protection– such as deeper soil-injections. The department conducted a pilot project in 2020–21 with pesticide applicators and local county agricultural commissioners to help develop alternative mitigation measures that better protect public health and additionally provide growers with compliance options that satisfy DPR’s strict regulatory requirements. DPR conducted the pilot project in regions where communities requested localized studies as part of their AB 617 Community Emissions Reduction program.

The proposed regulations would expand setbacks from occupied structures, limit application rates, acreage, and allowed application methods, and include more stringent use requirements between November to February when weather conditions can create higher air concentrations following an application. The regulations also propose requirements for lower-emission application methods for tree and vine applications, which have the highest application rates for 1,3-D.

The proposed regulations will address both potential cancer and acute health risks to non-occupational and residential bystanders from 1,3-D use, based on a health-protective regulatory target established last year after consultation with state and local agencies. In addition to these actions, DPR is currently working on separate regulations to address risks to workers from potential exposure to 1,3-D.

The mitigation measures proposed in the regulations are more health-protective than the current township cap program that limits 1,3-D use in the state.

DPR is accepting public comment on the regulations between Nov. 18 and Jan. 18 at 5 p.m. Comments can be submitted via U.S. mail or via email to, or by FAX at (916) 324-1491. Find more information on the 1,3-D regulations on DPR’s website, including information on a public hearing scheduled for Jan. 18.


The California Department of Pesticide Regulation protects human health and the environment by fostering safer and sustainable pest management practices and operating a robust regulatory system to evaluate and register pesticides and monitor and regulate their sale and use across the state.

DPR’s work includes conducting scientific evaluations of pesticides to assess and mitigate potential harm to human health or the environment prior to and following registration, registering all pesticides prior to sale or use in California, monitoring for pesticides in the air and water, and enforcing pesticide laws and regulations in coordination with 55 County Agricultural Commissioners and their combined 500 field inspectors across the state’s 58 counties. DPR invests in innovative research, outreach, and education to encourage the development and adoption of integrated pest management tools and practices and conducts outreach to ensure pesticide workers, farmworkers and local communities have access to pesticide safety information. More information about DPR.


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