United States
Environmental Protection
Agency
Prevention, Pesticides
and toxic Substances
(7508C)
EPA 738-F-02-009
July 2002
»ERr\ Disulfoton Facts
EPA has assessed the risks of disulfoton and reached an Interim Rerepstrafion Eligibility
Decision (TRED) for this organophosphate (OP) pesticide. Provided that risk mitigation measures are
adopted, disulfoton's individual, aggregate risks are within acceptable levels. Disulfoton is also
eligible for reregistration, once cumulative risks are considered.
EPA's next step is to consider the cumulative
risks of the OP pesticides, which share a common
mechanism of toxicity. The interim decision on
disulfoton will not be final until these cumulative
risks also are considered. Further risk mitigation
may be warranted at that time. I
Used on a variety of crops, disulfoton
residues in food do not pose a risk concjern. Drinking
water risk estimates suggest concern for potential
surface water exposure. However, these are .
conservative estimates based on screening level
models. Because of the conservative nature of these
estimates and because of some uncertainties in the
water assessment, the Agency believes ;that drinking
water risks are likely to be lower than the current
modeled estimates, and not of concern.; Therefore, to
address the potential concern for drinking water,
EPA is requiring confirmatory environmental fate
data and surface water monitoring datajfor disulfoton
and its degradates, Disulfoton's residential use as an
insecticide for use On ornamental flowers and
shrubs, including rose bushes, and outdoor potted
plants poses risk concerns to residential handlers for
a few scenarios. To address the scenarios of risk
concern, the registrant has agreed to the following
mitigation measures: limiting maximum application
-.latej-prohibitingapplication withcertain band.heldd&fiie^-
:v^paek^rig,'ffi&
including all indoor uses and use in home vegetable gardens. With this mitigatiorr limiting exposure
through household use, disulfoton fits into its own "risk cup" and does not pose aggregate risk
The OP Pilot Public Participation Procss
The organophosphates (OPs) are a group
of related pesticides that affect the functioning of
the nervous system. They are among EPA's
highest priority for review in implementing
provisions of the Food Quality Protection Act
(FQPA)of1996.
EPA encourages the public to participate
in the review of the OP pesticides. Through a six-
phasecf pilot public participation process, the
Agency has released for review and comment its
preliminary and revised scientific risk assessments
for individual OPs. (Please contact the OP
Docket, telephone 703-305-5805, or see EPA's
web site, www.epa.gov/pesticides/op.)
EPA is exchanging information with
stakeholders and the public about the OPs, their
uses, and risks through Technical Briefings,
stakeholder meetings, and other fora. USDA is
coordinating input from growers and other OP
pesticide users.
Based on current information from
interested stakeholders and the public, EPA is
making interim risk management decisions for
individual OP pesticides. The Agency will make
final decisions after considering the cumulative
risks of the OPs. (Please see
www.epa.aov/Desticides/cumulative.htm.')
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concerns. Other mitigation, measures are necessary to address worker and ecological risks for
disulfoton, which are of concern. To mitigate worker risk, EPA is requiring closed inixing/loading
systems for liquid formulations; closed loading and transfer for granular formulations; enclosed cabs
plus a dust-mist respirator for all handlers using ground application equipment; enclosed cockpits and
mechanical flaggers for aerial application; maximum personal protective equipment where closed
cabs are not feasible; and increased re-entry intervals for foliar application to certain crops. To
mitigate ecological risks, EPA is requiring reduced numbertoŁ applications allowed per year; reduced
maximum rates; phase out of certain uses; a 25-foot vegetative buffer between treated fields and
permanent water bodies; and a precautionary bee statement on labels. These measures substantially
reduce but do not fully mitigate worker and ecological risks. However, EPA believes that the
benefits of continued disulfoton use on certain commodities outweigh the worker and ecological risk.
For other commodities where benefits do not outweigh-the risk, use will be phased out by June 2004.
EPA is reviewing the OP pesticides to determine whether Ifeey meet current health, and safety
standards. Older OPs require decisions about thek eligibility for ^registration under FIFRA. OPs
with food, drinking water, residential, and any other non-occupational exposures must be reassessed to
make sure they meet the new FFDCA safety standard, effected by the Food Quality Protection Act
(FQPA)ofl996.
The disulfoton interim decision was made through the OP pilot public participation process,
which increases transparency and maximizes stakeholder involvement in EPA's development of risk
assessments and risk management decisions. EPA worked extensively with affected parties to reach
the decisions presented in this interim decision document
Next Steps
j^-isi*!!****
1. Numerous opportunities for public comment were offered as this decision was being
developed. However, because some uses are being phased out, the disulfoton ERED is issued
with a 30-day public comment period. (Please seewww.epa.gov/pesticides/rereeistration/
status^to or www.epa.gov/pesticides/op.
2. When EPA has considered fee cumulative risks of toe OP pesticides, the Agency will issue its
final tolerance reassessment decision for disulfoton and may request further risk mitigation
measures. The Agency will revoke 33 tolerances now, because there is either no registered
use or because the technical registrant has requested, andEPAhas approved, voluntary
cancellation of use on the commodities associated with these tolerances. Two tolerances for
disulfoton will be lowered now, and several tolerances will be modified to correct
cornmodity definitions. No tolerances wifl be raised and no new tolerances will be established
until cumulative risks have been considered for aU th& OPs.
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