As California pursues ambitious decarbonization targets, hydrogen has been proposed as a key technology for transforming hard-to-abate sectors. To support informed decision-making, CCST has been amplifying science and technology expertise for California's policymakers on this topic, including via the publications below.
As California pursues ambitious decarbonization targets, hydrogen has been proposed as a key technology for transforming hard-to-abate sectors. To support informed decision-making, CCST has been amplifying science and technology expertise for California's policymakers on this topic, including convening two expert briefings—one on decarbonizing with hydrogen and another focused on hydrogen’s role in the transportation sector. Building on this work, CCST is hosting a November 2024 workshop, "Aligning California's Hydrogen Research and Innovation Agenda," to explore critical hydrogen research gaps, ensuring that California’s hydrogen strategy is grounded in the latest scientific insights and aligned with its decarbonization goals.
CCST studies follow a process modeled after the National Academies study process with checks and balances at each stage. The report is a collaborative effort by a large number of experts serving in various capacities. See the report appendices for detailed information.
Responding to a request from the California Department of Pesticide Regulation (DPR), CCST will conduct a review of current fumigant use in California and a comprehensive assessment of available alternatives to these fumigants.
Gerald Holmes, PhD
Committee Chair
Cal Poly State University, San Luis Obispo
Alan Kolok, PhD
Committee Co-Chair
University of Idaho
Christine Carroll, PhD
CSU Chico
Julie Guthman, PhD
UC Santa Cruz, Emerita
Sandipa Gautam, PhD*
UC Agricultural and Natural Resources
Vernard Lewis, PhD*
UC Berkeley, Emeritus
Christopher Simmons, PhD**
UC Davis
Jenny Broome, PhD
Plant Health Consulting
Michael Rust, PhD*
UC Riverside
Kimberly Parra, MPH, PhD*
Harvard T.H. Chan School of Public Health
*Joined for Phase II
**Declared conflict of interest, described in bio.
See Steering Committee member and Author bios below.
Specific steps in the committee selection and approval process are as follows:
Cal Poly Strawberry Center
Gerald Holmes is the Director of the Strawberry Center at Cal Poly State University in San Luis Obispo, California. The Center is a partnership between Cal Poly and the California Strawberry Commission. Gerald received his Ph.D. in Plant Pathology from UC Riverside in 1994 then worked as a University of California Cooperative Extension Farm Advisor in Imperial County for three years. For the subsequent 12 years he was an Extension Vegetable Pathologist and Associate Professor at NC State University. He then worked six years as Product Development Manager for Valent USA Corporation before becoming Director of the Strawberry Center in 2014.
University of Idaho
Alan Kolok is an ecotoxicologist at the University of Idaho whose research focuses on the fate, transport, and biological impacts of anthropogenic chemicals, including pesticides. His academic background features a doctorate in environmental, population, and organismic biology from the University of Colorado, Boulder and a master’s degree in Fisheries and Aquatic Science from the University of Washington. He has published over 90 scientific, peer-reviewed papers on a variety of topics, including comparative physiology, environmental toxicology, environmental epidemiology, and the crowdsourced data revolution. He is also an editor for the journal, Environmental Toxicology and Chemistry, and recently authored, “Modern Poisons: A Brief Introduction to Contemporary Toxicology.”
CSU Chico
Christine Carroll is a Seattle-area native who earned her bachelor’s degree in economics at Arizona State University and a PhD in agricultural economics at UC Davis. Her doctoral dissertation looked for economically viable control options for Verticillium wilt in lettuce crops in Monterey and the Salinas Valley. That research project, and the collaboration with growers, plant pathologists, and other disciplines, got her hooked on agricultural economics. She joined the College of Agriculture in part because of the interdisciplinary structure of the college, which she sees as an opportunity build cross-disciplinary collaborations.
UC Santa Cruz
Julie Guthman has conducted multiple research projects on regulatory and civil society efforts to reduce the use of toxic substances in food production. This includes National Science Foundation- and USDA-funded projects that investigated the political economic and sociological challenges that California strawberry growers face for farming without fumigants or adopting more disease resistant varieties. Her book, Wilted: Pathogens, Chemicals, and the Fragile Future of the Strawberry Industry (2019) was awarded the highest book award in her home discipline of geography, the Meridian Prize of the American Association of Geographers. Most recently, she has been the principal investigator of the UC-AFTeR Project, a multi-campus collaboration that investigated Silicon Valley’s recent forays into food and agriculture and culminated in her newest book. Guthman’s other publications include two other multi-award winning monographs, an edited collection and over sixty articles in peer-reviewed journals. She has received an Excellence in Research Award from the Agriculture, Food and Human Values Society, the Martin M. Chemers Award for Outstanding Research from the Social Sciences Division at UC Santa Cruz, and the Distinguished Career Award from the Cultural and Political Specialty Group of the American Association of Geographers.
University of California Agricultural and Natural Resources
Sandipa Gautam, Ph. D., is an Assistant Cooperative Extension Area Citrus IPM Advisor with the University of California Agricultural and Natural Resources (UCANR). Gautam’s current program studies strategies for integrated pest management of arthropod pests of citrus. Before her current position, she worked as an Assistant Research Entomologist with UCR for 5 years and developed postharvest treatments, fumigants, and alternatives for citrus pests of export concern. Dr. Gautam earned a Ph.D. in Entomology from Oklahoma State University. Her Ph.D. dissertation research focused on circumventing ovicidal deficiencies of fumigants during postharvest fumigation.
UC Berkeley
Dr. Vernard Lewis earned his B.S., M.S., and Ph.D. degrees at the University of California, Berkeley in Entomology. He is an Emeritus Professor of Cooperative Extension in the Rausser College of Natural Resources. He is professionally known for his research on termites and other structural and household insect pests. Dr. Lewis was also a member of the United Nations Global Termite Expert Group and is a recent inductee into the Pest Management Hall of Fame. Dr. Lewis has travelled to over thirty-five countries as a researcher, consultant, and insect pest troubleshooter. He continues to stay involved in activities that promote the recruitment and retention of underrepresented minorities and women in science.
UC Davis
Dr. Christopher Simmons' research focuses on food system sustainability, with emphasis on circular economy approaches for recycling residual organic matter to benefit soil and crop health. In particular, his team uses multidisciplinary approaches to understand and advance biosolarization - a technology that harnesses microbial fermentation of organic matter in agricultural soils - as strategy to control soil pests and pathogens, improve soil fertility and water retention, and maintain robust soil microbial communities. By examining the microbial ecology, nutrient cycling, biopesticides, and other pest suppression mechanisms associated with biosolarization, Dr. Simmons' team has adapted diverse food processing residues, such as tomato pomace, grape pomace, almond hulls, date residues, and onion peels, as biosolarization soil amendments to inactivate phytoparasitic nematodes, fungal pathogens, and weed propagules. Additionally, his team has worked closely with commercial growers to test and demonstrate biosolarization as a fumigation alternative that can deliver benefits to crop health and yield.
Disclosure of Conflict of Interest
As a key part of CCST’s formal study process, CCST screens all provisional authors and Steering Committee members to ensure that no individual appointed to serve on a committee has a conflict of interest — any financial or other interest which conflicts with the individual’s service because it could significantly impair the individual's objectivity or could create an unfair competitive advantage for any person or organization. An objective determination is made whether a conflict of interest exists given the facts of the individual's financial and other interests, and the task being undertaken by the committee. A determination of a conflict of interest for an individual is not an assessment of that individual's behavior, character, or ability to act objectively despite the conflicting interest. For situations where CCST and the Program Committee determine that a conflict of interest is unavoidable, CCST will promptly and publicly disclose the conflict of interest.
Through this assessment we have concluded that proposed author Dr. Christopher Simmons has a conflict of interest.
We have also concluded that for this study to accomplish the tasks for which it was established, its members must include individuals with research and expertise in alternatives to fumigation.
After an extensive search, we have been unable to find another individual with the equivalent expertise of Dr. Christopher Simmons in evaluating alternatives to fumigation, and the Steering Committee has concluded that this conflict of interest will not inappropriately influence the outcome of the study.
Plant Health Consulting
Janet C. “Jenny” Broome, PhD, Independent Consultant, Plant Health Consulting. Dr. Broome received her PhD and MS degrees in plant pathology from UC Davis and a BA degree in biology from Swarthmore College. Dr. Broome was previously a Senior Research Manager and Scientist at Driscoll’s Inc. leading the Global Plant Health Department. Her team worked on berry pathogen diagnostics and developing and extending best management practices for nursery plant propagation and for independent growers. Her research at Driscoll’s focused on pre-plant soil plant health treatments such as anaerobic soil disinfestation, organic amendments, soil solarization, mobile soil steam pasteurization treatments, crop rotations relevant to organic berry crop production, as well as chemical fumigant alternatives to methyl bromide. In addition, she created the host plant resistance team to work with breeding and molecular biology teams to increase breeding efficiency through marker assisted selection. Before her 12 plus years at Driscoll’s, she worked at UC ANR’s Sustainable Agriculture Research and Education Program for 13 years, and as a Senior Environmental Research Scientist for the California Department of Pesticide Regulation. She is currently an Independent Consultant seeking to establish a UC Santa Cruz adjunct research professor position and engaged in plant health research projects in grapes and berries. She has numerous publications and over the years has served on scientific advisory committees for state and federal agencies as well as for industry and academic programs.
University of California, Riverside
Michael Rust earned his M.A. and Ph.D. in Entomology at the University of Kansas. He joined the Department of Entomology at the University of California Riverside in 1975 and retired in 2013. Since retirement, he has maintained an active research program. His area of research specialization is urban entomology with an emphasis on pests of structures. The research includes basic and applied studies on the control of ants, cockroaches, fleas, termites and yellowjackets. Some current research activities include the control of pestiferous yellowjackets in recreational areas and the potential of a new class of insecticide isoxazolines against urban pests.
Harvard T.H. Chan School of Public Health
Kimberly Parra, MPH, PhD, is a postdoctoral fellow at the Harvard T.H. Chan School of Public Health. Her research focuses on maternal exposures to endocrine disruptors during the perinatal period. Previously, Kimberly contributed to the CHAMACOS study at UC Berkeley, which examines agricultural pesticide exposures on families in the Salinas Valley, CA. She earned her PhD in Epidemiology from the University of Arizona, where she led a population-based study that examined ambient pesticide exposure and neighborhood deprivation in the birthing population in Arizona. Dedicated to advancing maternal and child health, Kimberly is committed to translating scientific research into evidence-based policies and interventions to address the needs of vulnerable populations.
Responding to a request from the California Department of Pesticide Regulation (DPR), CCST conducted a review of current fumigant use in California and a comprehensive assessment of available alternatives to these fumigants. Broadly, a fumigant is a volatile or volatilizable chemical compound used as a pesticide. Fumigants can be used as an insecticide, fungicide, disinfectant, nematicide, herbicide, and even a rodenticide. They can be applied in a wide variety of settings such as in the home, in structures, healthcare and food facilities, for crop growth and management, and to control vector-borne or animal-borne diseases.
Across two phases, the study assessed:
Although fumigants are used in a variety of settings, the study focused on three uses of fumigants: pre-plant soil fumigation, post-harvest commodity fumigation, and structural fumigation.
Fumigants covered in the study were limited to:
CCST conducted this study across two phases. The Phase I report, completed in February 2025, focuses exclusively on the pre-plant soil fumigants 1,3-D and chloropicrin and their alternatives.
The Phase II report, published February 2026, has an expanded scope that includes the four remaining pre-plant soil fumigants as well as the fumigants used for treating post-harvest commodities and structures. The final report, published July 2026, focused on pre-plant fumigants, specifically methyl bromide and three pesticides known as MITC generators: dazomet, metam-sodium, and metam-potassium.
