DPR Posts New Quarterly Data on 1,3-D Use in California

The Department of Pesticide Regulation (DPR) today released its quarterly data on the use of 1,3-dichloropropene (1,3-D) for Quarter 2 of 2026. Statewide use of 1,3-D – measured as Adjusted Total Pounds (ATP) – from January through June remains below the levels typically seen before DPR’s 2024 1,3-D regulation took effect. The recent regulations include stronger restrictions on how and where 1,3-D can be applied, including requirements for lower-emission application methods and more restrictive limits on how close applications can occur to other fields and structures.

At the local level, there are individual townships with higher than historic use in 2026, including one township in Merced County and one township in Kern County that exceeded a previous township cap. New 1,3-D regulations removed the cap on use and instead include emission-based restrictions to keep 1,3-D air concentrations below DPR’s regulatory thresholds. The increased use of 1,3-D in 2026 corresponds to increased crop planting in both counties. DPR analyzes 1,3-D use and potential impact on air quality and human health as part of its continuous evaluation of pesticides. For example, in the 1,3-D annual report, DPR will conduct additional analysis of relevant county data and will work with County Agricultural Commissioners to determine next steps, if needed, and to evaluate if current regulations are working as intended to address public health risks.