United States
              Environmental Protection
              Agency
Prevention, Pesticides
and Toxic Substances
(7508C)
EPA738-F-00-018
July 2001
                     Temephos  Facts
       EPA has assessed the risks of temephos and reached a Reregi strati on Eligibility Decision
(RED) for this organophosphate (OP) pesticide.  Provided that risk mitigation measures are
adopted, temephos is eligible for reregistration. A cumulative assessment is not warranted.
       Temephos is one of a few
organophosphates registered to control mosquito
larvae, and is the only organophosphate with any
appreciable larvicidal use. It is an important
resistance management tool for mosquito
abatement programs. Temephos residues in food
and drinking water  do not pose risk concerns
since temephos has no food uses and, because of
its limited use pattern, is not expected to be found
in drinking water. Residential risk is not of
concern since temephos has no residential use and
its use in mosquito  abatement programs does not
result in residential  exposure. With mitigation
measures, temephos' worker and ecological risks
will be eligible for reregistration.

       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. Because
temephos has no food uses, or other uses that
would result in exposure to children, it will not be
included in the cumulative assessment of OPs.
           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,
         http://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
         most individual OP pesticides, and will make  final
         decisions through a cumulative OP assessment.
       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 temephos decision was made through the OP pilot public participation process, which

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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 decision document, which concludes the OP pilot process for
temephos.
Uses
       Temephos is used to control mosquito, midge, gnat, punkie, and sandfly larvae in non-
       potable water (stagnant, saline, brackish and temporary water bodies), waters high in
       organic content, highly polluted water, including moist areas, woodland pools, shallow
       ponds, edges of lakes, swamps, marshes, tidal waters, intertidal zones, catch basins, and
       tire piles. It is an important resistance management tool for mosquito abatement
       programs.

       Annual usage is approximately 25,000 to 40,000 pounds of active ingredient per year.
       Temephos' use has declined in recent years due to deletion of the use on citrus.
Health Effects
       Temephos 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
      Dietary risks from food and drinking water are not of concern since temephos has no food
       uses. Because of its limited use pattern, it is not expected to be found in drinking water.

      Residential risk is not of concern since temephos has no residential use, and its use in
       mosquito abatement programs does not result in residential exposure.

      EPA has risk concerns for workers who can be exposed both dermally and through
       inhalation while mixing, loading, and/or applying temephos.

      Because temephos is applied directly to non-potable water, it is not expected to have a
       direct impact on terrestrial animals. Risk quotients for freshwater fish exceed levels of
       concern only for endangered species and restricted use. No acute toxicity data are
       available for marine fish species. Risk quotients exceed levels of concern for aquatic
       invertebrates.

Risk Mitigation

       In order to support a reregistration eligibility decision for temephos the following risk
mitigation measures are necessary:

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      To mitigate risks to mixers, loaders, applicators and other handlers, either closed mixing
       and loading systems or additional personal protective equipment (PPE) will be needed.

       Where closed systems are not feasible or are not used, handlers will need to wear:

              Cloth coveralls over long-sleeved shirt and long pants;
              Chemical-resistant gloves;
              Chemical-resistant footwear plus socks;
              Chemical-resistant headgear (if overhead exposure).

       See the temephos RED for application specific measures.

       Temephos must be applied only by public health officials, personnel of mosquito
abatement districts and other similar government agencies or personnel under contract to these
entities.

      To mitigate ecological risks, temephos:

              May be applied only to non-potable water (stagnant, saline, brackish and
              temporary water bodies), waters high in organic content, highly polluted water,
              including moist areas,  woodland pools, shallow ponds,  edges of lakes, swamps,
              marshes, tidal waters, intertidal zones,  catch basins, and tire piles;
              May not be reapplied within 7 days of initial application unless monitoring
              indicates that larval populations have reestablished, or weather conditions have
              rendered initial treatments ineffective;
              Limit use of high application rates to non-potable water (stagnant, saline, brackish
              and temporary water bodies), high in organic matter content, highly polluted
              water, and tire piles and where monitoring has confirmed a lack of control at
              typical rates.

Next Steps

      The temephos RED contains a generic and a product-specific Data Call-In(s) (DCI) that
       outline further data requirements for this chemical.  A complete DCI, with all pertinent
       instructions, is being sent to registrants under  separate cover.

      The temephos RED 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.

       Registrants are developing route-specific dermal toxicity data.  If these data indicate lower
       risk to workers than currently estimated, PPE requirements may be revised.

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For More Information

       To obtain a copy of the RED document, please contact the OPP Public Regulatory
Docket (7502C), US EPA, Ariel Rios Building, 1200 Pennsylvania Avenue NW, Washington, DC
20460, telephone 703-305-5805. Electronic copies of the RED, the fact sheet, and supporting
documents are available on the Internet.  See
http://www.epa.gov/pesticides/reregistration/status.htm or http://www.epa.gov/pesticides/.

       Printed copies of the RED and fact sheet can be obtained from EPA's National Service
Center for Environmental Publications (EPA/NSCEP), PO Box 42419, Cincinnati, OH 45242-
2419, telephone 1-800-490-9198; fax 513-489-8695.

       The temephos RED document also will be available from the National Technical
Information Service  (NTIS), 5285 Port Royal Road, Springfield, VA 22161, telephone 1-800-
553-6847, or 703-605-6000.

       For more information about EPA's pesticide reregi strati on program,  the temephos RED,
or reregi strati on of individual products containing temephos, please contact the Special Review
and Reregistration Division (7508C), OPP, US EPA, Washington, DC 20460, telephone 703-308-
8000.

       For information about the health effects of pesticides, or for assistance in recognizing and
managing pesticide poisoning symptoms, please contact the National Pesticide
Telecommunications Network (NPTN). Call toll-free 1-800-858-7378, from 6:30 am to 4:30 pm
Pacific Time,  or 9:30 am to 7:30 pm Eastern Standard Time, seven days a week.  Their Internet
address is http://ace.orst.edu/info/nptn/.

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