CDPR Releases 2024 Report for 1,3-D: No Action Needed!

The California Department of Pesticide Regulation has released their draft annual report on the effectiveness of the 1,3-Dichloropropene (1,3-D) Regulation. This annual report evaluates the effectiveness of the 1,3-dichloropropene (1,3-D) regulation effective January 2024. The report identifies and evaluates the ten highest-use townships in California and evaluates the air concentrations at all six DPR’s 1,3-D monitoring stations. This first annual report also checks compliance with the 1,3-D regional use limit (township cap) of 136,000 adjusted total pounds (ATP)1 temporarily in effect. In 2024, 7,008,972 pounds of 1,3-D were used on 43,736 acres statewide, corresponding to 4,053,244 ATP and 1,296,684 pounds of emissions. This is the lowest 1,3-D use and acreage since 2009. The crops with the most use were almonds, strawberries, sweet potatoes, and carrots. Applications using field fumigation methods at 18-inch minimum injection depth largely transitioned to methods at 24-inch minimum injection depth resulting in a reduction in emissions, especially in almond crops. Modeling results showed that the highest estimated air concentrations were 26.8 ppb, 15.1 ppb, and 0.41 ppb for the 24-hour, 72-hour, and 1-year time periods, respectively. These concentrations were below DPR’s regulatory target concentrations of 55 ppb (72-hour average) and 0.56 ppb (70-year average). Additionally, the highest measured air concentrations at the monitoring stations were 7.19 ppb and 0.21 ppb for the 24-hour and 1-year time periods, respectively. These concentrations were below the thresholds of 55 ppb (24-hour average) and 0.27 ppb (1-year average) that trigger additional evaluation. All townships complied with the township cap of 136,000 ATP, with the highest township having 113,628 ATP. In summary, DPR’s pesticide use report (PUR) data analyses of high-use townships and ambient air concentrations from air monitoring stations within DPR’s Air Monitoring Network (AMN) indicate that current regulatory measures are functioning as intended. CDPR concluded “there is no evidence at this time to suggest that additional actions are necessary to meet regulatory goals of DPR Regulation 22-005.”