After considering public comment and all available studies, EPA has denied the Natural Resources Defense Council’s (NRDC) petition to revoke all tolerances and cancel all registrations of 2,4-dichlorophenoxyacetic acid (2,4-D), a phenoxy herbicide and plant growth regulator that has been used in the U.S. since the 1940s. It is currently found in approximately 600 products registered for agricultural, residential, industrial and aquatic uses. The NRDC had filed the petition in November 2008.

In 2005, as part of the regulatory process to ensure pesticides meet current regulatory standards, EPA completed a review on the registration and safety of the tolerances for 2,4-D. The agency determined that all products containing 2,4-D were eligible for re-registration, provided certain changes were incorporated into the labels and additional data were generated and submitted to the EPA for review.

During the recent review of the petition, EPA evaluated all the data cited by NRDC and new studies submitted to EPA in response to the re-registration decision, including an extended one-generation reproduction study examining 2,4-D’s potential for endocrine disruptor, neurotoxic and immunotoxic effects. This study and EPA’s comprehensive review confirmed the agency’s previous finding that the 2,4-D tolerances are safe.

EPA also reviewed NRDC’s request that all 2,4-D product registrations be cancelled. Based on studies addressing endocrine effects on wildlife species and the adequacy of personal protective equipment for workers, EPA concluded that the science behind current ecological and worker risk assessments for 2,4-D is sound and that there is no basis to change the registrations.

EPA documents responding to NRDC’s petition on 2,4-D are available at When the Federal Register document is published, it will be available with the related documents in docket EPA-HQ-OPP-2008-0877 at