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Updated Human Health Risk Analyses for Chlorpyrifos

For Release: November 10, 2016

EPA has revised the human health hazard assessment and drinking water exposure assessment for chlorpyrifos that supported our October 2015 proposal to revoke all food residue tolerances for chlorpyrifos. EPA has further analyzed watershed data from across the United States and characterized dietary exposure risk from drinking water residues in order to better understand the risk of chlorpyrifos exposure. EPA will make a final decision by March 31, 2017.

EPA’s revised analyses do not result in a change to the EPA’s proposal, but having considered the advice of the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) Scientific Advisory Panel (SAP), we are proposing to modify the scientific analysis that supports that finding. The revised analyses indicate that expected residues of chlorpyrifos on food crops exceed the safety standard under the Federal Food, Drug, and Cosmetic Act (FFDCA).  In addition, the majority of estimated drinking water exposures from currently registered uses, including water exposures from non-food uses, continue to exceed safe levels even taking into account more refined drinking water exposures. 

These analyses will be available for a 60-day comment period upon publication in the Federal Register (see Notice of Data Availability) in docket EPA-HQ-OPP-2015-0653 at EPA will make a final decision by March 31, 2017.

View the 2016 revised human health risk assessment and the refined drinking water assessment. These analyses were available for a 60-day comment period in docket EPA-HQ-OPP-2015-0653 at We specifically solicited comments on the use of all new analyses and information. Given the significance of this information to EPA’s proposal to revoke all chlorpyrifos tolerances, the Agency is accepting comment on the information and analyses referred to in this notice as well as reopening comment on any other aspect of the proposal or the underlying support documents that were previously made available for comment.

Learn more about the revised human health hazard assessment.