CCST Report Assesses the Use of Fumigants 1,3-D and Chloropicrin in California

FOR IMMEDIATE RELEASE

Responding to a request from the California Department of Pesticide Regulation (DPR), the California Council on Science and Technology (CCST) completed the report “Fumigant Use in California and an Assessment of Available Alternatives: Phase I Report on 1,3-D and Chloropicrin.”

DPR announced the release of the report today via a press release. The full independent, scientific, and technical assessment is now available to download at DPR’s website.

The Phase I report reviews the pre-plant soil fumigants 1,3-D and chloropicrin and their alternatives. Work is currently underway on Phase II, with a scope that includes four additional pre-plant soil fumigants as well as fumigants used for treating post-harvest commodities and structures.

The fumigants 1,3-D and chloropicrin are classified as restricted materials both at the federal level and in California, with strict requirements for their use under a permitting process.

Cal Poly Strawberry Center Director Gerald Holmes, PhD, and University of Idaho Professor Emeritus of Ecotoxicology Alan Kolok, PhD, served as co-chairs of the study’s four-member CCST Steering Committee — working with the authors of the study, UC Davis Professor Christopher Simmons, PhD, and Independent Plant Health Consultant Jenny Broome, PhD.

“For decades, California growers have relied on 1,3-D and chloropicrin for effective, high-yield pre-plant fumigation, particularly for the state’s strawberries and almonds,” said co-Chairs Holmes and Kolok. “However, studies suggest that these fumigants may pose significant risks to human health, particularly at high levels of exposure. Low-dose, chronic exposures experienced by our agricultural communities, while more difficult to study, are also of concern. Our report takes a comprehensive approach to considering potential alternatives to 1,3-D and chloropicrin, both chemical and non-chemical, highlighting their promise and their shortcomings. We address the barriers to adoption of fumigant alternatives and discuss some potential policy paths forward.”

The report concludes that no one alternative could serve as a drop-in replacement for either of these two fumigants. Rather, different fumigant alternatives may be useful for different regions, crops, and pest pressures. Fumigant alternative research has increasingly focused on identifying promising combinations of complementary fumigant alternatives.

“We’re proud to live in a state with an agricultural bounty as plentiful and diverse as California’s,” said Julianne McCall, PhD, CCST’s Chief Executive Officer. “At CCST, we’re honored to help this team of experts investigate the science and impacts of fumigants and the availability of potential alternatives that could help keep our agricultural economies vibrant and support the well-being of California’s most vulnerable communities, as we continue the effort into the next phase.”

As defined by CCST’s study process that is applied to all peer-reviewed reports, efforts were made to solicit input from expert individuals who have been directly involved in, or who have special knowledge of, the problem under consideration. CCST identified and connected with individuals to provide these perspectives through a variety of avenues including public calls for expertise, recommendations from study team members, and targeted searches or outreach. These external experts provided their perspectives in the form of meetings with the study team or by serving as external peer reviewers of the report. These efforts supplemented a rigorous process of identifying report authors and steering committee members, all of whom are required to complete a non-disclosure agreement (NDA) and undergo conflict of interest (COI) review to allow frank and open discussions among the study team and ensure that no personal or financial interests could compromise the integrity of the final report.

CCST makes every effort to ensure that a balanced and diverse set of perspectives are engaged throughout the study process, including voices from academia, industry, and civil society sectors. However, given CCST’s uniquely robust and extensive study and peer review processes, CCST reports do not require additional opportunities for broader public comment. As such, not all who expressed interest in contributing to the report had the opportunity to engage in its production. This ensures the utmost scientific and technical quality, maintains objectivity, minimizes all potential sources of conflicts of interest, while delivering the report in a timely manner.

Per CCST’s standard study process, the report was subject to peer review by independent experts, while another independent expert served as Report Monitor to oversee the process, ensuring that peer review comments were sufficiently addressed. An Oversight Committee reviewed the entire process, including conflict-of-interest declarations. The report’s findings and conclusions are based on a review of published literature and official and voluntary databases.

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About the California Council on Science and Technology

The California Council on Science and Technology is a nonpartisan, nonprofit organization established via the California State Legislature in 1988. CCST engages leading experts in science and technology to advise state policymakers ― ensuring that California policy is strengthened and informed by scientific knowledge, research, and innovation.