DPR Statement on CDFA Laboratory Error
The California Department of Pesticide Regulation (DPR) conducts an Air Program that monitors ambient air concentrations of 40 pesticides at four locations throughout the state, and monitors for two pesticides at two additional sites. The California Department of Food and Agriculture’s (CDFA) laboratory, the Center for Analytical Chemistry, performs the analysis of air samples collected by DPR and DPR publishes the results of these analyses. CDFA notified DPR that it had identified an error in the lab analyses conducted on samples collected via air canister that the lab analyzed between February 16, 2011, and November 27, 2024 (view CDFA memorandum). The lab error resulted in underreporting the presence of two pesticides: methyl bromide and 1,3-dichloropropene (1,3-D) over this time period.
In its preliminary analysis of the lab’s updated data, DPR has identified three new readings of 1,3-D air concentrations in 2018 and 2022 that exceeded screening targets or regulatory thresholds. Detections of a pesticide below a screening level or regulatory target indicates there is a low level of risk to human health or the environment.
The updated 1,3-D readings underscore the need for regulatory requirements on 1,3-D to protect public health and the environment. DPR conducted additional air studies, using a different sampling method, to develop the current and proposed 1,3-D regulations in response to the ambient air readings. The scientific analysis for the 1,3-D regulations did not rely upon any of the data from the Air Program that was affected by the lab error. Although the CDFA laboratory error regarding historic ambient air concentrations does not impact the scientific analysis that informed the proposed 1,3-D regulations, DPR is evaluating its approach to 1,3-D regulation, along with all comments received during the first comment period on its proposed regulations, to make sure that the regulations are appropriately protective. DPR will take appropriate action and communicate with the public following that review.
DPR anticipates that updated data to correct for the error in previously reported air monitoring results will be available in its Pesticide Air Monitoring Results Database by the end of February.
At DPR’s Pesticide Registration and Evaluation Committee meeting on March 21, which will include an opportunity for public comment, the CDFA lab will provide a public presentation on the analysis error, revised data calculations on air samples collected by DPR’s Air Program, and both the CDFA lab and DPR will provide an overview of next steps.