Could California be introducing new PFAS pesticides? Here's what you need to know

The U.S. Environmental Protection Agency (EPA) has recently authorized the use of two pesticide chemicals that experts warn may contain persistent "forever chemicals."

The agency approved cyclobutrifluram for application on romaine lettuce, cotton, soybeans, as well as ornamental plants and turf. Meanwhile, isocycloseram received approval for use on a broader set of crops, including brassica vegetables such as cabbage, broccoli, and Brussels sprouts.

Both chemicals are currently under review by California state authorities. They will not be applied on crops in California until this state-level evaluation is completed, which could take months or even years. Scientists and environmental advocates are raising alarms about potential negative effects on human health and ecosystems, noting that these pesticides add to the growing list of PFAS (per- and polyfluoroalkyl substances) already in use in the state.

"Californians should be concerned," said Nathan Donley, director of environmental health science at the Center for Biological Diversity.

PFAS chemicals, a large family of human-made substances, are found in products ranging from nonstick cookware to firefighting foam and pesticides. The EPA stated that the new pesticide approvals "provide farmers with additional options to manage crops and increase food production in the U.S."

An analysis by the Environmental Working Group shows that approximately 2.5 million pounds of PFAS pesticides are used annually in California, with Fresno County reporting the highest levels at over 2 million pounds between 2018 and 2023. These figures are based on data from the California Department of Pesticide Regulation.

PFAS chemicals are known for their strong carbon-fluorine bonds, which make them extremely resistant to breakdown, sometimes persisting for centuries. The newly approved pesticides contain molecules with one carbon atom fully bound to fluorine. While the federal definition of PFAS requires two or more fluorinated carbons, some scientific and regulatory organizations consider even a single fully fluorinated carbon as PFAS, according to Clare Pace, assistant project scientist at UC Berkeley.

Exposure to PFAS has been linked to health issues including reduced fertility, higher cancer risk, and weakened immune response. The Western Growers Association highlighted the need for new pest control tools due to crop damage and resistance challenges in recent years.

PFAS pesticides are already widely used nationwide and in California. "Sixty-six active PFAS pesticide ingredients were registered with the EPA as of 2021, and these new approvals expand that list," said Pace. California allows around 50 of the EPA-approved PFAS pesticide ingredients.

Jane Williams, executive director of California Communities Against Toxics, called the use of fluorinated chemicals on crops "dangerous for both human health and the environment," warning that these substances accumulate in the food chain.

Isocycloseram and cyclobutrifluram can degrade into trifluoroacetic acid, a short-chain PFAS that dissolves in water and is difficult to remove. Pace noted that this could increase concentrations in groundwater, surface water, and oceans, with uncertain consequences.

The California Department of Pesticide Regulation conducts detailed scientific reviews before any pesticide can be sold or applied in the state. This process evaluates the persistence, breakdown, toxicity, and overall environmental and human health risks of the chemicals. Review durations vary, often taking several years for new active ingredients.

Donley expressed concern over the historical pattern, noting that "after the DDT experience, it is alarming to see similar chemicals being approved again."

Author: Sophia Brooks