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EPA Completes Scientific Testing of Pesticide Products for PFAS

This original announcement was published by the EPA on May 30, 2023. Click here for more information.


Today, the U.S. Environmental Protection Agency (EPA) is taking another step in addressing concerns that per- and polyfluoroalkyl substances (PFAS) have been found in pesticide products by releasing a summary of the laboratory analysis of 10 pesticide products reported to contain PFAS residues. EPA did not find any PFAS in the tested pesticide products, differing from the results of a published study in the Journal of Hazardous Materials. EPA is also releasing its newly developed and validated analytical methodology used in the testing process alongside the summary of its findings. EPA is confident in the results of this newly released method, which is specifically targeted to detect the presence of PFAS in pesticide products formulated with surfactants.   

Since learning about potential PFAS contamination in a small number of mosquitocide products in September 2020, EPA has taken a number of steps to address this issue. This includes releasing data in March 2021 that preliminarily determined that PFAS in those specific products was most likely formed from a chemical reaction during the container fluorination process which then leached into the pesticide product, releasing another study in September 2022 testing the leaching potential of PFAS over a specific time into test solutions packaged in different brands of HDPE fluorinated containers, and notifying manufacturers (including importers), processors, distributors, users, and those that dispose of fluorinated HDPE containers and similar plastics that the presence of PFAS formed as a byproduct in these containers may be a violation of the Toxic Substances Control Act. Following that notification, the Department of Justice, on behalf of EPA, filed a complaint against Inhance, the company that manufactured the plastic mosquitocide containers in which PFAS was found, for its failure to comply with TSCA’s notice, review, and determination requirements prior to manufacture.  

As a continuation of these ongoing efforts, EPA has completed its verification analysis of a study published in September 2022 in the Journal of Hazardous Materials entitled “Targeted analysis and Total Oxidizable Precursor assay of several insecticides for PFAS.” This study reported the presence of PFOS in six of 10 pesticide products tested. 

EPA evaluated the 10 pesticide products included in this study using two different test methods to detect PFAS. The first method was developed by the Agency to specifically measure PFAS in pesticide samples containing surfactants and non-volatile oils, and the second method was used in the study published in the Journal of Hazardous Materials. 

EPA obtained samples of the specific pesticide products from the study author and purchased additional products with the same EPA registration numbers on the open market to conduct analyses. EPA tested all samples using both methods and   did not detect the presence of PFOS, nor any of 28 additional PFAS it screened for, above the lowest level that our lab instruments can detect (0.2 parts per billion) in any of the pesticide products using either method of detection. The equipment and methodology used by EPA would have shown PFAS detections if present in those pesticide products given that our level of detection (LOD) is 2,500 times more sensitive than the LOD reported by the equipment used by the study author. EPA requested additional information, including raw data from the study author, but did not receive any beyond the published results. EPA’s study report contains additional scientific details regarding how the two methods differ and the significance of using the Agency’s new method when testing these specific formulations. 

One of the most important differences between the two methods is that EPA’s method ensures accurate measuring of PFAS by eliminating interference from the oils and surfactants present in these formulations which can result in false positive detections.  

EPA’s PFAS Strategic Roadmap renewed the Agency’s commitment to using sound science and investing in research to proactively stop PFAS chemicals from entering the environment. This latest action is an important step in EPA’s ongoing efforts to better understand and manage, when necessary, pesticide formulations that contain PFAS to ensure enduring and protective solutions. As part of our continuing efforts, EPA will continue to invest in scientific research to fill gaps in understanding of PFAS, to identify which PFAS may pose human health and ecological risks at which exposure levels and develop methods to better test and measure them.