United States
Environmental Protection
Agency
Prevention, Pesticides
and Toxic Substances
(7508C)
EPA 738-F-01-004
October 2001
Pirimiphos-methyl Facts
EPA has assessed the risks of pirimiphos-methyl and reached an Interim Reregistration
Eligibility Decision (ERED) for this organophosphate (OP) pesticide. Provided that risk mitigation
measures are adopted, pirimiphos-methyl fits into its own "risk cup"-- its individual, aggregate risks are
within acceptable levels. Pirimiphos-methyl also is eligible for reregistration, pending a fuE
reassessment of the cumulative risk from all OPs.
Used primarily on stored corn and sorghum
grain and seed, in cattle ear tags and for the fogging
treatment of iris bulbs, pirimiphos-methyl residues in
food alone do not pose risk concerns. With
mitigation reducing worker exposure to pirimiphos-
methyl by requiring closed system mixing and loading
systems for admixture grain and seed treatment, and
requiring additional personal protective equipment for
workers, risk will not be of concern. Pirimiphos-
methyl ecological risks are also below the Agency's
level of concern.
EPA's next step under the Food Quality
Protection Act (FQPA) is to complete a cumulative
risk assessment and risk management decision
encompassing all the OP pesticides, which share a
common mechanism of toxicity. The interim decision
on pirimiphos-methyl cannot be considered final until
this cumulative assessment is complete. Further risk
mitigation may be warranted at that time.
EPA is reviewing the OP pesticides to
determine whether they meet current health and
safety standards. Older OPs need decisions about
their eligibility for reregistration under FIFRA OPs
with residues in food, drinking water, and other non-occupational exposures'also must be reassessed to
make sure they meet the new FQPA safety standard. •
The OP Pilot Public Participation Process
The organophosphates are a group of
related pesticides that affect the functioning of the
nervous system. They are among EPA's highest
priority for review under the Food Quality
Protection Act.
EPA is encouraging the public to
participate in the review of the OP pesticides.
Through a six-phased pilot public participation
process, the Agency is releasing 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, and will make final
decisions through a cumulative OP assessment.
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The pirimiphos-methyl 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, which concludes the OP pilot process
for pirimiphos-methyl.
Uses - ,
• Pirimiphos-methyl is a post-harvest insecticide used on stored com and sorghum grain and
seed, incorporated into cattle ear tags, and used for the fogging treatment of iris bulbs. It is
used to control various insects such as mealy bugs and mites (on iris bulbs), horn and face flies
(on cattle), and cigarette beetle, confused flour beetle; corn sap beetle; flat grain beetle; hairy
fungus beetle; red flour beetle; sawtoothed beetle, granary weevil, maize weevil, merchant
grain beetle, rice weevil, lesser grain borer, and angoumois grain moth, Indian Meal moth and
almond moth (on corn and sorghum grain and seed).
• Annual domestic use is low— approximately 12,000 pounds of active ingredient per year. Total
usage is allocated mainly to stored corn grain (39%) ear tags for cattle/calves (36%), stored
sorghum gram (15%), corn seed (5%), and sorghum seed (5%). Regions with significant
usage on cattle include the Gulf Coast, Midwest, and West, and states with significant usage on
corn grain include Iowa and Texas. V
• There are no residential uses for pirimiphos-methyl.
Health Effects
• Pirimiphos-methyl can cause cholinesterase inhibition in humans; that is, it can overstimulate
the nervous system causing nausea, dizziness, confusion, and at very high exposures (e.g.,
accidents or major spills), respiratory paralysis and death.
Risks
Acute and chronic dietary risks from food alone do not exceed the Agency's level of concern.
Drinking water exposure is not of concern because there are no outdoor uses which would
result in water contamination. Therefore a drinking water assessment was not completed for
this organophosphate.
Worker risks are of concern for the mixer/loader/applicator when using pirimiphos-methyl as a
top dress or admixture treatment for stored corn and sorghum graintand seed; a fogging
treatment on iris bulbs, and when applying cattle ear tags.
Ecological risks are not of concern to the Agency. Although pirimphos-methyl is highly toxic
to birds and fish, these risks are not of concern based on the use pattern of pirimiphos-methyl.
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Risk Mitigation
In order to support a reregistration eligibility decision for pirimiphos-methyl, the following risk
mitigation measures listed below are necessary:
To mitigate risks to agricultural workers (mixers/loaders) during admixture treatment to corn
and sorghum grain and seed:
0 '• - •
8 Require the use of engineering controls such as closed mixing and loading systems.
• To mitigate risks to workers (mixers/loaders/applicators) during top dress treatment to com
and sorghum grain and seed: ;
• Require all mixers/loaders/applicators to wear coveralls over long sleeve shirt'and
pants, chemical resistant footwear, socks, and chemical resistant gloves. In addition,
mixers and loaders must wear a chemical resistant apron.
• To mitigate worker risks" from cattle ear tag use: .
• Handlers must wear chemical resistant gloves in addition to long sleeve shirt, long
pants, shoes, and socks.
• To mitigate risks to agricultural workers for the fogging treatment of iris bulbs:
• Require all mixers and loaders to wear coveralls and chemical resistant gloves.
? • .
• Require applicators to use a stationary or cart-mounted fogging device, which when
activated functions automatically without an operator present.
» Require applicators to have available to them for use in case'they must enter the area
during treatment before ventilation requirements have been met, coveralls, chemical .
resistant gloves, chemical resistant headgear and a self-contained breathing apparatus
(SCBA) (MSHA/NIOSHA approval number prefix TC-13E)}
• Require that entry by any person into the treatment area, other than a properly trained
and equipped handler using the PPE specified, be prohibited until the area has been
adequately ventilated.
Next Steps
• Numerous opportunities for public comment were offered as this decision was being
developed. The pirimphos-methyl IKED therefore is issued in final (see www. epa. gov/REDs/
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or www.epa.gov/pesticides/op ), without a formal public comment period. The docket remains
open, however, and any comments submitted in the future will be placed in this public docket.
The pirimiphos-methyl IRED contains a generic and product-specific Data Call-in (DCI) that
outline(s) further data requirements for this chemical. A complete DCI, with all pertinent
instructions, is being sent to registrants under separate cover.
The pirimiphos-methyl IRED also describes labeling amendments for end-use products and
data requirements necessary to implement the mitigation measures outlined in the document.
Instructions for registrants on submitting the revised labeling can be found in the set of
instructions for product-specific data that is being sent under separate cover.
"When the cumulative risk assessment for all organophosphate pesticides is completed, EPA
will issue its final tolerance reassessment decision for pirimiphos-methyl and may request
further risk mitigation measures. The Agency will revoke 14 tolerances and amend 5
tolerances for pirimiphos-mehtyl IRED, now. For all OPs, raising and/or establishing
tolerances will be considered once a cumulative assessment is completed.
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