Early OP Work (diazinon, ethoprop, tribufos, and phosmet)

•	In March 2023, the Agency released updated occupational and non-occupational spray drift
exposure (ORE) risk assessments for diazinon, ethoprop, tribufos and phosmet.

•	The Agency identified the following potential risks for each pesticide:

o For diazinon, ethoprop, phosmet, and tribufos: potential risks to workers who mix,
load, and apply the pesticides, and to bystanders (including farmworkers) who could be
exposed to spray drift

o For phosmet and tribufos: potential risks to workers conducting certain post-application
activities (e.g., weeding, hand harvesting, or workers re-entering treated areas).

•	Registration review for these pesticides is not scheduled to be completed until 2025-2026;
ecological risks will also be considered at that time.

•	EPA has taken accelerated action to address the potential risks identified in the four updated
ORE assessments by working with the technical registrants to implement mitigation measures
early to protect farmworkers and other people that work with and may be exposed to these
pesticides from potential risks.

•	The technical registrants for diazinon, Adama US and Drexel Chemical Company, have agreed to
mitigation measures including:

o The cancellation of aerial applications, wettable powderformulations, and backpackand
mechanically-pressurized handgun applications (aside from liquid, broadcast foliar use
for ornamentals, as it is an APHIS use), and
o Spray drift reduction measures, including buffer restrictions near residential and
institutional sites to reduce exposure to bystanders.

•	The technical registrant for ethoprop, AMVAC, has agreed to mitigation measures including:

o Reducingthe 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 applications only, due to the lack of other effective nematicides for these
crops);

o Requiring coarser droplet size anda maximum release heightto reduce the potentialfor

pesticide spray drift; and
o Including buffers between application sites and residential areas.

•	The technical registrant for phosmet, Gowan, has agreed to mitigation measures including:

o Voluntarily canceling the registration of three products that contain phosmet;
o Prohibiting the use of mechanically pressurized handgun for the riskiest use;
o Prohibiting aerial and chemigation application on certain crops;
o Requiring longer waiting periods between application and certain post-application

activities for stone and pome fruits, and grapes;
o Requiring coarser droplet size to reduce the potential for pesticide spray to drift and

expose people nearby;
o Including buffers between application sites and residential areas;
o Reducing the application rate for some uses; and

o Requiring use of increased personal protective equipment (PPE) (including gloves,
respirators, etc.)

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•	The technical registrants for tribufos, AMVAC and RedEagle, have agreed to mitigation
measures including:

o Reducing the maximum application rate;

o Limiting the pesticide amount handled for aerial applications;

o Requiring coarser droplet size to reduce the potential for pesticide spray to drift and

expose people nearby;
o Implementing no-spray buffers between application sites and residential areas;
o Prohibiting certain post-application activities for a longer duration after application for

higher application rates; and
o Requiring 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.

•	Implementation

o EPA has requested that registrants send their revised labels within 45 days, which has
already occurred for diazinon, and is expected in early July for the other 3 chemicals,
o EPA will prioritize reviewing and stamping these labels as they come in and intends to

have all labels stamped/approved by the end of the year, sooner if possible,
o Once labels are approved, products must include the new label within 12 months of the
stamped approval date.

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