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fipronil NYS DEC Letter - Registration Application Approval 11/96

New York State Department of Environmental Conservation
Division of Solid & Hazardous Materials
50 Wolf Road, Albany, New York 12233-7250
Phone 518-457-6934 FAX 518-457-0629

Kandy Walker Duke, Ph.D.
Director, Regulatory Affairs
Rhone Merieux, Incorporated
115 Transtech Drive
Athens, GA  30601

Dear Dr. Duke:

RE:  Registration of Pesticide Products Frontline Top Spot for Cats (EPA Reg.
     No. 65331-2) and Frontline Top Spot for Dogs (EPA Reg. No. 65331-3);
     Denial of Registration of Frontline Spray Treatment (EPA Reg. No. 65331-1)

We have reviewed and accepted for registration the application received on
July 26, 1996 to register Frontline Top Spot for Cats and Frontline Top Spot
for Dogs.  These products are classified as general use pesticides in New York
State.  The application received on June 10, 1996 to register Frontline Spray
Treatment is denied; the details are discussed below.  All products contain
the new active ingredient fipronil.

Frontline Spray Treatment contains 0.29 percent of the active ingredient,
fipronil, and is labeled for control of fleas and ticks on dogs, puppies, cats
and kittens.  Frontline Top Spot for Cats and Frontline Top Spot for Dogs
contain 9.7 percent fipronil and are labeled for the same use as Frontline
Spray Treatment but are applied with a pre-measured pipette applicator to a
single area of skin between the pet's shoulder blades.

Staff from the New York State Department of Health (NYSDOH) and the
New York State Department of Agriculture & Markets reviewed the submitted
application package.

The NYSDOH addressed human health risks resulting from use of the products.
Technical fipronil was moderately toxic to laboratory animals by the oral,
inhalation and dermal routes of exposure and was mildly irritating to skin and
eyes.  The formulated products were not very toxic nor irritating to
laboratory animals in  acute studies.

Technical fipronil caused a number of toxicological effects in chronic animal
studies at relatively low doses.  Clinical signs of neurotoxicity were
reported in  rats and dogs at doses as low as 0.07 and 1.0 milligrams per
kilogram body weight per day (mg/kg/day), respectively.  Although not
specifically conducted to evaluate neurological effects, clinical signs of
neurotoxicity were also reported in a 21-day dermal exposure study in rabbits
at a dose of 10 mg/kg/day, indicating that neurotoxicity can result from
dermal exposures.

The United States Environmental Protection Agency (USEPA) indicated concern
about chronic risks to commercial pet groomers and conditionally registered
the Frontline products for a period of two years (due to expire on June 1,
1998).  As a condition of federal registration, Rhone Merieux, Incorporated is
required to submit information on inhalation and dermal exposure of these
workers, as well as information on Frontline product use.  The submitted
registration package contained little information on exposure to fipronil from
use of Frontline or on the likely use practices of Frontline products by
commercial pet groomers.

Given the application method of the two Frontline Top Spot products (by
pre-measured pipette), significant exposure of groomers or pet owners is
unlikely.  The Frontline Spray Treatment product, however, appears to pose a
greater exposure potential to commercial pet groomers.  Based on label
statements and information about Frontline Spray Treatment application rates
to pets, we estimated potential exposures to commercial pet groomers according
to the following scenario:


Frontline Spray Treatment label directions state that "Approximately 1 to 2
per pound of the animal's body weight will be required."

      each pump delivers 1.5 milliliter (ml) of Frontline Spray Treatment

      for a 25 pound (11.4 kilogram) dog, the application rate would be 37.5 -
      75 ml/animal

      Frontline Spray contains 0.29 percent fipronil, equal to 2.9 milligrams
      fipronil per ml

      therefore, each 11.4 kilogram (kg) animal would receive an application
      of about 108.8 - 217.5 mg fipronil

      If a 60 kg commercial groomer treats ten such pets per day, they would
      be applying 1088 - 2175 mg fipronil, equivalent to 18.1 - 36.2 mg/kg/day
      for the groomer.

These estimates suggest that if a groomer routinely inhales or dermally
absorbs even less than one percent of the fipronil estimated to be applied
each day, exposure would exceed that which caused neurological effects in a
chronic rat study.

Given the exposure potential and the toxicological properties of fipronil, it
is our decision that Frontline Spray Treatment will not be registered in New
York State at this time.  For further consideration of Frontline Spray
Treatment for registration in New York State, Rhone Merieux, Inc. must submit
a new application and application fee for a major change in labeling and
provide 1) the information submitted to the USEPA to complete the conditions
under federal registration or 2) additional information which would lessen our
concerns for commercial pet groomers.

With regard to pet toxicity, we did not identify any significant concerns
regarding toxicity to pets from use of any of the three products.

The New York State Certificate of Pesticide Registration and a copy of the
stamped "ACCEPTED" labels for Frontline Top Spot for Cats and Frontline Top
Spot for
Dogs are enclosed for your records.

If you have any questions regarding these products, please contact Ms. Maureen
Serafini, Supervisor of our Pesticide Product Registration Section, at (518)


Norman H. Nosenchuck, P.E.
Division of Solid & Hazardous Materials


cc: w/enc. - W. Smith, Cornell University, PMEP
             N. Kim/T. Grey, NYS Dept. of Health
             J. Huntley, NYS Dept. of Agriculture & Mkts.