US EPA announces next steps to restrict chlorpyrifos use

The U.S. Environmental Protection Agency (EPA) on Tuesday announced additional measures to protect federally threatened or endangered (listed) species and their designated critical habitats from the effects of chlorpyrifos. The measures include new product labels containing additional protections and Endangered Species Protection Bulletins that set geographically specific limitations on pesticide use. Collectively, these measures will not only protect listed species but also reduce exposure to non-listed species.

Chlorpyrifos is an organophosphate insecticide commonly used to control foliage and soil insect pests. Pesticide products containing chlorpyrifos are registered for use on agricultural crops and on nonfood sites such as ornamental plants in nurseries, golf course turf, or as wood treatment.

Background on Chlorpyrifos

In August 2021, EPA revoked all tolerances for chlorpyrifos, which establish an amount of chlorpyrifos that is allowed on food. This action essentially stopped the use of chlorpyrifos on all food and animal feed. EPA took this action in response to an April 2021 order from the U.S. Court of Appeals for the Ninth Circuit for the Agency to issue—within 60 days—a final rule addressing chlorpyrifos tolerances, without taking public comment or engaging in ″further fact-finding.″ 

On November 2, 2023, the U.S. Court of Appeals for the Eighth Circuit vacated EPA’s August 2021 rule revoking all tolerances. All chlorpyrifos food tolerances were reinstated on December 28, 2023. On February 5, 2024, EPA issued a Federal Register notice to amend the Code of Federal Regulations to reflect the court's reinstatement of those tolerances. At this time, all pre-August 2021 final rule chlorpyrifos tolerances have been reinstated and are currently in effect.

EPA will soon issue a proposed rule to revoke the tolerances associated with all food uses, except the 11 food and feed crop uses identified in the 2020 Proposed Interim Decision. Based on the available data, retaining only the 11 food uses (along with geographic limitations and additional mitigation measures) could decrease average annual pounds of chlorpyrifos applied in the U.S. by 70% as compared to historical usage.

Chlorpyrifos Label Changes to Protect Endangered Species

Under the Endangered Species Act, EPA is responsible for ensuring that its pesticide actions do not jeopardize listed species or destroy or adversely modify their critical habitats. When EPA determines in its biological evaluation that a pesticide may affect these species or habitats, EPA must consult with the National Marine Fisheries Service (NMFS), the U.S. Fish and Wildlife Service, or both (collectively referred to as the ″Services″). Once consultation is complete, the Services develop a Biological Opinion (BiOp) that, among other things, determines if the pesticide is expected to jeopardize listed species or adversely modify their critical habitats, and if so, require measures to protect these species and habitats.

For chlorpyrifos, EPA determined in 2022 that then-registered uses had the potential to adversely affect one or more listed species. After consultation between EPA and NMFS, and the chlorpyrifos registrants, on June 30, 2022, NMFS issued a ″no jeopardy″ BiOp for chlorpyrifos and two additional organophosphate pesticides, diazinon and malathion. During that consultation, the registrants committed to amend their product labels and registrations to include measures that reduce runoff and spray drift (the movement of a pesticide through the air to an area other than the intended application area) from treated areas into species’ habitats. EPA also committed to issuing Endangered Species Protection Bulletins, available on the Bulletins Live! Two website, which set geographically specific pesticide use limitations that would protect listed species and their critical habitats.

The mitigations for chlorpyrifos include restrictions on when to apply, restrictions on tank mixing, and use limitations related to both runoff and drift, as well as wind speed restrictions.

All registrants have submitted these product labeling amendments to EPA, as well as amendments describing how to report ecological incidents associated with pesticide applications, should users observe any. EPA has also posted agreed-upon Bulletins.

For additional information on the NMFS BiOp, visit EPA’s website.

The registration review process for chlorpyrifos is ongoing. In early 2025, EPA plans to issue an amended Proposed Interim Decision for chlorpyrifos for public comment, followed by an Interim Decision in late 2025.