California Agencies Moving to Further Restrict Chlorpyrifos

Len WilcoxCalifornia Corner, Regulation

Chlorpyrifos is being targeted again by environmental agencies. According to a press release from California Citrus Mutual (CCM), the California Environmental Protection Agency announced in mid-August that both California Department of Pesticide Regulation (DPR) and the Office of Environmental Health Hazard Assessment are pursuing new restrictions on chlorpyrifos. CCM says that chlorpyrifos is one of the most important and widely used agricultural pesticides in the nation.

CCM anticipates that additional restrictions will take the form of larger buffers or setbacks, additional restrictions on application methods, and a limit on the size of applications. County ag commissioners could be instructed to limit the size or number of permits issued.

CCM, along with other commodity groups and associations, are united in opposing any further restrictions as unjustified. DPR’s risk assessment is flawed, according to CCM, and doesn’t meet the scientific criteria for establishing human risk. The draft evaluation uses modeling of unrealistic exposure scenarios, such as a child directly downwind of an application every day for 21 days.

The combination of unrealistic exposure assumptions, the use of modeling analyses that lacks validation for offsite concentration predictions, and the proposal of additional uncertainty factors based on hypothetical neurodevelopment effects all add significant conservatism that results in a conclusion that over-estimates risks exponentially. Fifty years of peer-reviewed and replicated scientific studies contradict DPR’s assessment of risk.

DPR will be accepting written comments and questions on the draft risk assessment until October 2, 2017. These comments will be part of the formal record going forward. CCM will be submitting comments critical of the risk assessment, condemning DPR’s departure from the use of established scientific practices, and opposing any additional restrictions on chlorpyrifos applications.

Growers are encouraged to also submit comments. CCM staff is available to provide assistance. Visit the the CCM website at for more details.

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About the Author

Len Wilcox

Correspondent at Large for Citrus Industry Magazine and AgNet West