New York State Department of Environmental Conservation
Division of Solid & Hazardous Materials
Bureau of Pesticides Management
Pesticide Product Registration Section
625 Broadway, Albany, New York 12233-7257
Phone 518-402-8768 FAX 518-402-9024
September 5, 2001
RETURN RECEIPT REQUESTED
Ms. Linda H. Aschbrenner
State Registration Specialist
P.O. Box 12014
Research Triangle Park, NC 27709-2014
Dear Ms. Aschbrenner:
Re: Registration of One New Pesticide Product, Regent 4 SC Insecticide (EPA Reg. No. 264-582), Which Represents a
Major Change in Labeling for the Active Ingredient Fipronil
The Department of Environmental Conservation (the Department) has completed the review of your
application, received February 13, 2001, for the registration of Regent 4 SC Insecticide (EPA Reg. No. 264-582) in New
York State. Regent 4 SC Insecticide is labeled to control insect pests on field corn. Fipronil is currently
registered in New York State for use in products labeled to control fleas and ticks on dogs, puppies, cats and kittens,
and to control indoor/outdoor household insects. The proposed use of Regent 4 SC Insecticide on field corn represents
a major new use pattern for the active ingredient fipronil in New York State.
The application was deemed complete on June 4, 2001 and a registration decision is due by November 1,
The Department has reviewed the information supplied to date in support of the major change in labeling
application for Regent 4 SC Insecticide (EPA Reg. No. 264-582).
The formulated Regent product was moderately toxic to laboratory animals by the oral, inhalation and
dermal routes of exposure, was mildly irritating to rabbit eyes and skin and was not a skin sensitizer. While fipronil
is relatively toxic, exposure potential from the use of the Regent product on field corn is limited. The product is
directly applied to soil furrows only at the time of planting and the application rate is relatively low. The label
requires that the applicators and other handlers wear coveralls over short-sleeved shirts and short pants, waterproof
gloves, chemical-resistant footwear plus socks, chemical-resistant headgear for overhead exposure, protective eyewear,
a dust/mist filtering respirator and a chemical-resistant apron when cleaning or mixing and loading.
There are no chemical specific federal or state drinking water/groundwater standards for fipronil.
Based on its chemical structure, fipronil falls under the 50 micrograms per liter general New York State drinking water
standard for "unspecified organic contaminants" (10 NYCRR Part 5 - Public Water Systems).
Available laboratory data indicate that below the soil surface fipronil dissipates by soil binding
followed by slower biotic mediated processes. The major route of degradation on the soil surface may be photolysis
and/or soil binding followed by slower biotic mediated processes. These data indicate that fipronil is slightly mobile
to relatively non-mobile in soils tested, but may be moderately persistent under some environmental conditions.
Laboratory data indicate that fipronil degrades slowly under alkaline hydrolytic conditions, but appears to be stable
to hydrolysis at pHs 5 and 7. Field data appear to support these laboratory data. Half-lives of 1.1 to 1.5 months for
bare soil and 0.4 to 0.5 months for turfed soil were reported in field data. Half-lives of 3.4 to 7.3 months were
reported for in-furrow applications. In bare soil and in-furrow applications, fipronil residues were detectable mainly
in the 0 to 0.15 meter (m) soil depth. Field data for in-furrow applications did report limited fipronil residues in
the 0.15 to 0.45 m soil depth segments. Since fipronil absorbs to soil/sediment, the potential for groundwater
contamination is considered relatively low in most soils. Movement off-target would appear to be associated with
sediment contained in surface water and runoff water.
Based on the environmental fate data, Regent 4 SC Insecticide, when used as labeled, will not have a
significant impact on the groundwater of New York State.
Fipronil is extremely toxic to marine invertebrates. Marine invertebrates will be impacted at water
concentrations three orders of magnitude lower than those affecting freshwater organisms. Transport to aquatic
habitats with surface runoff of even a minute percentage of the applied fipronil or metabolites will negatively impact
The Department requested additional label language in order to insure the protection of sensitive
aquatic life in New York State. The Department has, in the past, required that identical exclusionary 100 foot buffer
zones around surface waters be added to product labels. The intent is to exclude the use of products as toxic as
Regent from areas bordering surface waters. The Department has determined that 100 feet is a reasonable distance for
eliminating the potential for harm from extremely toxic compounds.
Use of Regent as directed on the original label would result in an unacceptable level of risk to
marine invertebrates on both an acute and chronic basis. The Mysid shrimp acute Lethal Concentration 50 (LC50) (median
lethal concentration) for fipronil is 140 parts per trillion (ppt), the chronic Lowest Observed Effect Concentration
(LOEC) is 5 ppt. With this extreme toxicity, transport of parent and/or metabolites to aquatic habitats, at levels
typical of compounds with fipronil's chemical characteristics, will result in adverse effects.
Once in surface waters, the only significant degradation pathway of fipronil or metabolites is via
photolysis. While their aqueous photolysis half-life is relatively short they may persist in deeper or turbid water
for extended periods before adsorbing to the water column or sediment organic carbon.
The November 1997 United States Environmental Protection Agency (USEPA) Environmental Fate and Effects
Division Section 3 Eligibility Decision Chapter for Fipronil Use on Corn, which considered laboratory data and various
studies, stated that "based on the environmental fate assessment, fipronil and its degradates (MB46513, MB46136 and
MB45950) can potentially move into surface waters." Later in the surface water assessment section; "Although fipronil
and its degradates exhibit moderate soil sorption affinities, these compounds are expected to exist in runoff waters
primarily in the dissolved state."
The federally accepted Regent label contained the following language: "Runoff from treated areas
may be hazardous to aquatic and estuarine organisms in adjacent aquatic and estuarine sites. Do not apply within 20
yards of lakes, reservoirs, rivers, permanent streams, marshes, natural ponds, estuaries, commercial aquaculture
facilities or other bodies of water that convey water to these areas. Protection of aquatic areas may be enhanced by
maintaining all or a portion of this buffer in vegetative cover."
The Department requested that the buffer zone be increased from 60 feet (20 yards) to 100 feet, or add
a statement that specifies a 100 foot buffer zone in New York State.
The Department maintains that increasing the buffer zone which appears on the Regent label by 40 feet,
to a 100 foot buffer zone around surface waters, would be required in order to insure the protection of sensitive
aquatic areas. The Mysid shrimp acute LC50 for fipronil is 140 ppt and the chronic LOEC is 5 ppt. The runoff modeling
conducted by the Department included the fipronil metabolites of aquatic toxicological concern produced via aerobic
soil metabolism. Metabolite MB46136 is 6.6 times more toxic and metabolite MB45950 is 1.9 times more toxic to Daphnia
than the parent fipronil compound. A similar toxicity differential between parent and metabolites was assumed for
Mysidopsis, the marine test organism. The extremely high level of toxicity and the fraction of applied fipronil and
degradates that is likely to be transported in runoff poses an unacceptable level of risk to marine invertebrates.
Aventis CropScience submitted an application for a label amendment to the USEPA which was stamped
"ACCEPTED" on July 30, 2001. The federally accepted label now contains the following language: "Runoff from
treated areas may be hazardous to aquatic and estuarine organisms in adjacent aquatic and estuarine sites. Do not
apply within 20 yards (in New York State, do not apply within 100 feet or 33 yards) of lakes, reservoirs, rivers,
permanent streams, marshes, natural ponds, estuaries, commercial aquaculture facilities or other bodies of water that
convey water to these areas. Protection of aquatic areas may be enhanced by maintaining all or a portion of this
buffer in vegetative cover."
The final printed labeling with the above-mentioned New York State specific language (in bold face font
for increased visibility) was received by the Department on August 22, 2001.
Therefore, the Department hereby accepts for restricted use registration in
New York State the major change in labeling application of Regent 4 SC Insecticide (EPA Reg. No. 264-582).
Regent 4 SC Insecticide is classified as a federally "RESTRICTED USE PESTICIDE" and as such, the
product is restricted in its purchase, distribution, sale, use, and possession in New York State. According to the New
York State Department of Environmental Conservation Regulations 6 NYCRR 326.3 (a): "It shall be unlawful for any
person to distribute, sell, offer for sale, purchase for the purpose of resale, or possess for the purpose of resale,
any restricted pesticide unless said person shall have applied for, and been issued a commercial permit."
Furthermore, the product may only be purchased and used by certified applicators in New York
Please contact the Pesticide Certification Section, at (518) 402-8748, if you require information
concerning commercial permits or pesticide applicator certification.
Enclosed are your New York State stamped "ACCEPTED" label and a copy of the Certificate of Registration.
If you have any questions, please contact Ms. Jeanine Broughel, of my staff, at
Maureen P. Serafini
Bureau of Pesticides Management
cc: w/enc. - N. Kim/D. Luttinger - NYS Dept. of Health
R. Zimmerman/ R. Mungari - NYS Dept. of Ag. & Markets
G. Good/W. Smith - Cornell University, PMEP