EPA Reaches Agreements on Early Mitigation Measures for Three More Organophosphate Pesticides

Released on May 25, 2023

The U.S. Environmental Protection Agency (EPA) is announcing new mitigation measures for three additional organophosphate pesticides: ethoprop, phosmet, and tribufos. The Agency worked with the registrants of these pesticides to develop mitigation measures several years ahead of the scheduled completion of EPA’s registration review work on these chemicals, expediting protection for farmworkers and other people who work with these pesticides.

In March 2023, EPA released updated Occupational and Residential Exposure (ORE) assessments for the three organophosphate pesticides (and for a fourth organophosphate, diazinon, for which early mitigation measures were announced last month). The assessments showed that some uses of these pesticides posed health risks to workers who mix, load, and apply the pesticide; workers conducting certain post-application activities (e.g., hand weeding, hand harvesting, or re-entering treated areas); and to bystanders (including farmworkers) who could be exposed through spray drift. EPA is pursuing mitigation for these three pesticides earlier than would be achieved through the standard registration review process. That process requires re-evaluation of registered pesticides every 15 years to ensure that as the ability to assess risk evolves and as policies and practices change, pesticides continue to meet the statutory standard of causing no unreasonable adverse effects on human health or the environment.

Phosmet

Phosmet is a widely used agricultural insecticide that provides pest control benefits to growers of orchard fruit, nut, and other crops. In the updated ORE assessment, the most significant risks of concern for people who work with phosmet were for those using mechanically pressurized handguns on many use sites, mixers and loaders for most aerial and chemigation uses sites, and for post-application activities on a variety of stone and pome fruits and grapes.

The technical registrant for this pesticide, Gowan, has agreed to mitigation measures including:

The registrant requesting to voluntarily cancel the registration of three products that contain phosmet;
Prohibit the use of mechanically pressurized handgun for the riskiest uses;
Prohibit aerial and chemigation application on certain crops;
Require longer waiting periods between application and certain post-application activities for stone and pome fruits, and grapes;
Require coarser droplet size to reduce the potential for pesticide spray to drift and expose people nearby;
Include buffers between application sites and residential areas;
Reduce the application rate for some uses; and
Require use of increased personal protective equipment (PPE) (including gloves, respirators, etc.).

The updated phosmet ORE assessment is available in the registration review docket EPA-HQ-OPP-2009-0316 at www.regulations.gov.

Tribufos 

Tribufos is an herbicide used as a pre-harvest defoliant on cotton. The updated ORE assessment identified potential risks of concern to workers who mix, load, and apply the pesticide; workers conducting certain post-application activities; and bystanders (including farmworkers) who could be exposed to spray drift.

The technical registrants for this herbicide, AMVAC and RedEagle, have agreed to mitigation measures including:

Reduce the maximum application rate;
Limit the pesticide amount handled for aerial applications;
Require coarser droplet size to reduce the potential for pesticide spray to drift and expose people nearby;
Implement no-spray buffers between application sites and residential areas;
Prohibit certain post-application activities for a longer duration after application (when higher application rates are used); and
Require closed loading systems for ground applications(already required for aerial applications) to reduce exposure to people mixing and loading the pesticide into the application equipment.

The updated tribufos ORE assessment is available in the registration review docket EPA-HQ-OPP-2008-0883 at www.regulations.gov.

Ethoprop

Ethoprop is an insecticide and nematicide used on a variety of agricultural crops prior to, or at the time of, planting. All ethoprop products are classified as restricted use pesticides due to acute dermal toxicity. The updated ORE assessment identified potential risks of concern to workers who mix, load, and apply the pesticide and to bystanders who could be exposed through spray drift.

The technical registrant for this insecticide-nematicide, AMVAC, has agreed to mitigation measures including:

Reduce the maximum application rate for all liquid products (exception allowed when nematode pressure is high for treatment of potato, sweet potato, and Easter Lily crops using banded application only, due to the lack of other effective nematicides for these crops);
Require coarser droplet size and a maximum release height to reduce the potential for pesticide spray to drift and expose people nearby; and
Implement no-spray buffers between application sites and residential areas.

The updated tribufos ORE assessment is available in the registration review docket EPA-HQ-OPP-2008-0560 at www.regulations.gov.

Stakeholders will have an opportunity to comment on the registration review for these three organophosphates during the next step of the process, when the proposed interim decisions are published for comment along with full updated human health risk assessments. Per the registration review process, these proposed decisions will be followed by interim or final decisions, which will implement additional label mitigation measures for risks not covered by the early mitigation initiatives. EPA expects to issue the proposed interim decisions for tribufos in 2025, and for ethoprop, phosmet, and diazinon in 2026.