United States
Environmental Protection
Agency
Prevention, Pesticides
and Toxic Substances
(7508C)
EPA738-F-00-013
November 2000
SEPA Oxamyl Facts
EPA has assessed the risks of oxamyl and reached an Interim Reregistration Eligibility Decision
(IRED) for this carbamate pesticide. With the risk mitigation measures required, oxamyl fits into its
own "risk cup"-- its individual, aggregate risks are within acceptable levels. Oxamyl also is eligible for
reregistration, pending a full reassessment of the cumulative risks.
Used on several vegetables, fruits, and non-
food items, oxamyl residues in food and drinking
water do not pose risk concerns for the general
population. Although oxamyl showed potential
aggregate risks to children (1-6 years), the Agency
does not expect risks to children due to the rapid
reversibility of cholinesterase inhibition. Oxamyl has
no residential uses, and fits into its own "risk cup."
With required mitigation measures, oxamyl worker
and ecological risks are believed to be significantly
reduced.
EPA's next step under the Food Quality
Protection Act (FQPA) is to complete a cumulative
risk assessment and risk management decision
encompassing carbamate pesticides that share a
common mechanism of toxicity. The interim decision
on oxamyl cannot be considered final until this
cumulative assessment is complete. Further risk
mitigation may be required at that time.
EPA is reviewing the carbamate pesticides to
determine whether they meet current health and safety
standards. Carbamates need decisions about their
eligibility for reregistration under FIFRA. Additional carbamates 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 oxamyl interim decision was made through an abbreviated public participation process,
which increases transparency and maximizes stakeholder involvement in EPA's development of risk
The Carbamate Public Participation Process
The carbamates are a group of related
pesticides that affect the functioning of the nervous
system. EPA considers them a high priority for
review under the Food Quality Protection Act.
EPA encourages the public to participate
in the review of the carbamate pesticides. The
Agency released the preliminary scientific risk
assessments for review and comment earlier and is
now releasing the revised scientific risk
assessments for oxamyl and its interim
reregistration decision. The Docket telephone is
703-305-5805, or see EPA's web site,
www.epa.gov/pesticides/reregistration/oxamyl/
EPA is exchanged information with
stakeholders and the public about oxamyl to
address the uses and risks through stakeholder
meetings, conference calls, and other fora. USDA
coordinated input from growers and other oxamyl
pesticide users.
Based on current information from
interested stakeholders and the public, EPA is
making interim risk management decisions for
individual carbamate pesticides, and will make final
decisions through a cumulative carbamate
assessment.
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assessments and risk management decisions. EPA worked with affected parties to reach the decisions
presented in this interim decision document.
Uses
A systemic and contact insecticide/acaricide and nematicide, oxamyl is a restricted use
pesticide used on apples, bananas, carrots, celery, citrus, cotton, cucumbers, eggplants, garlic,
ginger, muskmelon (including cantaloupe and honeydew melon), onion (dry bulb), peanuts,
pears, peppers, peppermint, pineapples, plantains, potatoes, pumpkins, soybeans, spearmint,
squash, sweet potatoes, tobacco, tomatoes, watermelons, yams. Oxamyl is also used on
Non-bearing apple, cherry, citrus, peach, pear, and tobacco.
• Approximately 800,000 of oxamyl active ingredient (a.i.) are applied annually. Although cotton
accounts for most of the usage, 600 thousand pounds a.i. oxamyl is used on only 7 percent of
total cotton acreage. Oxamyl is applied 1-2 times per season when it is used, usually at a rate
of about 0.4 pounds a.i. per acre. For most other crops, oxamyl is generally applied 1 to 2
times per season around 1 Ib. ai/A. Rates as low as 0.2 Ib ai/A may be used.
There are no residential uses.
Health Effects
Oxamyl 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 dietary risks from food and drinking water are below the level of concern for all
segments of the population, except childrenl-6 years old.
Chronic dietary risks were not assessed for oxamyl due to the rapid reversibility of ChEI.
The Agency believes the acute aggregate (food and water) risks to children (1-6 years) is
largely an overestimated risk concern because the assessment does not account for the rapid
reversibility of ChEI, which occurs within 2 to 3 hours. The Agency believes the results from
an ongoing drinking water study will confirm the assessed risks.
The current occupational assessment indicates risk concerns for all use scenarios at the current
maximum label rate. Post-application risks for workers entering treated fields are generally not
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of concern under the current restricted entry intervals (REI), except for hand-harvesting of
citrus tree crops.
• However, the Agency believes that implementing the mitigation measures which includes rate
reductions, engineering controls, additional personal protective equipment, and several
voluntary cancellations will effectively reduce exposure and risk to a level that is not of concern
to the Agency. The Agency is also increasing the REI for hand-harvesting of citrus tree crops
and expects the risks to be reduced to level that is not of concern.
There may be some acute and chronic risks to avian and mammalian species, as well as,
potential concerns for endangered species of freshwater invertebrates. However, the Agency
believes that the mitigation measures summarized below and the "restricted" use classification
will reduce potential ecological the risks and adequately mitigate risks.
Risk Mitigation
To mitigate risks to handlers and workers:
Reduce maximum aerial application rate to 1.0 Ib ai/A for foliar applications on all
crops except cotton.
• Reduce maximum chemigation application rate to 2.0 Ib ai/A for all crops except
cotton.
Reduce maximum rate to 0.5 Ib ai/A for cotton, except for AZ and CA (1.0 Ib ai/A
with closed systems); and reduce maximum seasonal rate to 3.0 Ib. ai/A/year.
• Reduce maximum soil application rate to 4.0 Ib ai/A for all crops, except mint and
pineapple, which must be reduced to 2.0 Ib ai/A.
Reduce seasonal maximum applications for all crops to 8 per crop and incorporate all
groundboom soil treatments by water or mechanical means.
• Require enclosed cockpits for aerial applicators and closed mixing/loading systems in
CA and AZ for cotton use at 1 Ib. ai/A.
Maintain PPE for all uses (baseline and coveralls, chemical resistant shoes, socks,
chemical resistant gloves, chemical resistant apron, head gear for airblast, and an
organic vapor respirator).
Also, the registrant has decided to voluntarily cancel the following uses:
• Seed piece dip (yams).
Soybean use.
Soil broadcast treatment for cotton.
To mitigate the ecological risks:
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Measures mentioned above are expected to affect the ecological concerns.
Next Steps
• The oxamyl IRED is being issued in final (see www.epa.gov/REDs/ or
www.epa.gov/pesticides/reregistration/oxamyll without a formal comment period. The docket
remains open, however, and any comments submitted will be considered in any future actions.
To effect risk mitigation as quickly as possible, the Agency is requiring that all labels must be
amended to include the above mitigation and submitted to the Agency within 90 days after
issuance of this IRED.
The registrant must submit the final results of the drinking water study by the year 2001.
• When the cumulative risk assessment for carbamates, including oxamyl is complete, EPA will
issue its final tolerance reassessment decision for oxamyl and may require further risk mitigation
measures. Similarly, the Agency may reconsider any part of this interim decision based on new
information which may come to the Agency's attention. The Agency will revoke fourteen
tolerances because there are either no registered uses or because the commodity is no longer
considered a significant feed item; and decrease three tolerances because available data
supports the decrease. Raising/or establishing new tolerances will be considered once a
cumulative assessment is completed.
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