United States
Environmental Protection
Agency
Prevention, Pesticides
and Toxic Substances
(7508C)
EPA738-F-01-002
September 2001
Ethion Facts
EPA has assessed the risks associated with the organophosphate (OP) pesticide ethion, and
identified risk mitigation measures and data needed to reduce and better characterize those risks. As
reflected in the Agency's reregistation Eligibility Decision (RED) document, the registrants of ethion
have requested voluntary cancellation of their
products rather than committing to develop the addition;
data. These data include developmental
neurotoxicity studies, and data on the effects of
water treatment on ethion in drinking water. The
voluntary cancellations will be "phased-in" to
facilitate the users' transition to other products. In
the interim before sale, distribution, and use of ethion
cease, the registrants have agreed to measures which
mitigate the worker and ecological risks associated
with ethion.
The ethion agreement was reached after the
risk assessment and mitigation proposal were
completed 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 during the development of the
risk mitigation proposal. The agreement on the
voluntary cancellation, based on the registrants'
decision not to develop the required data, concludes
the OP pilot process for ethion. The registrants have
informed users of the interim risk mitigation measures
and the phase-out schedule, explained further below.
Uses
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 in implementing 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. The Agency will make
final decisions after considering the a cumulative
risks of the OP. (Please see
An insecticide and acaricide, ethion is used to control leaf-feeding insects, mites, and scales on
citrus, and flies and ticks on cattle. Use on citrus accounts for more than 98% of the ethion
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used, with the large majority of that amount used on oranges and grapefruit in Florida. There
are no residential uses.
Estimates of domestic use range from more than 400,000 Ibs. for 1997 to approximately
50,000 Ibs. for 1999. Use has dropped in recent years because of drought conditions in
Florida and the emergence of pest control alternatives.
Risks
Based on the data currently available, residues of only ethion in food do not pose risk concerns.
The Agency has developed drinking water risk estimates for ethion based primarily on screening level
exposure assessments. These estimates exceed, in some cases, acceptable levels of drinking water
risk. While the Agency believes that the exposure and risk are likely reduced below those levels by
water treatment, additional data on the effect of water treatment on residues were needed.
• EPA has risk concerns for workers who mix, load, and/or apply ethion to citrus. These risks
are associated with hand-held sprayers; airblast mixing, loading, and application; and reentry
into treated areas by workers. While data are insufficient to assess the risks associated with
the handling of cattle eartags impregnated with ethion, the Agency believes it is prudent to
reduce potential exposure of this type.
Acute risks are of concern for aquatic organisms, especially aquatic invertebrates. Chronic
risks are of concern for birds and fish; data are lacking for aquatic invertebrates.
Risk Mitigation
The registrants have requested a voluntary cancellation action that will end the sale and
distribution of ethion by December 2003. The last legal use of ethion will be in December 2004.
Labeling for ethion end-use products manufactured for use beginning with the 2002 use season will
inform users of the phase-out schedule and incorporate the following risk mitigation measures:
• To mitigate risks to agricultural workers:
All ethion products for use on citrus will be classified as Restricted Use Pesticides.
On citrus, only airblast applications will be allowed, except for spot treatment of snow
scale.
• Spot treatments will only be made with a high-pressure hand-gun attached to a truck-
or trailer-mounted tank; applicators making the spot treatments will wear cotton
coveralls over long-sleeved shirt and long pants, shoes, socks, chemical resistant
gloves, and a dust/mist respirator; applicators will use no more than 2.5 Ibs ai/day,
diluting to 250 gallons for a final concentration of 0.01 Ib ai/gal.
Airblast applications will be made using enclosed cabs.
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Closed systems will be used for mixing/loading operations which support airblast
applications. (The registrants have agreed that production in Fall/Winter 2001/2002
will be in appropriate containers.)
• For reentry into citrus groves which have been treated with ethion, the Restricted Entry
Interval (REI) will be five days, with an exemption for scouting and irrigation activities
after three days.
• To mitigate risks to workers handling cattle eartags:
Persons applying cattle eartags containing ethion will wear chemical-resistant gloves.
• To mitigate ecological risks:
• All ethion products for use on citrus will be classified as Restricted Use Pesticides.
Next Steps
• The registrants will submit the label amendments.
Tolerances for commodities with no associated permissible use site (tea and raisins) will be
revoked at this time. Other tolerance actions will follow the cancellation.
Labels of ethion end-use products manufactured for use beginning January 1, 2002 will inform
users of the product phase-out and incorporate the risk mitigation measures described above.
• Sale and distribution of ethion will end December 31, 2003.
• The last legal date for use of ethion will be December 31, 2004.
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