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Bifenthrin - Denial to Register a Major Change in Labeling for Biflex 3/94

New York State Department of Environmental Conservation
50 Wolf Road, Albany, New York 12233-7250
                                    MAR 17 1994
Mr. John F. Wright
Manager, Product Development, PCO
ACG Specialty Products
FMC Corporation
P.O. Box 8
Princeton, New Jersey 08543
Dear Mr. Wright:
Re: Denial of Application to Register a Major Change in
    Labeling for the Pesticide Product Biflex TC
    Termiticide (EPA Reg. No. 279-3112)
     The New York State Department of Environmental Conservation (the
Department) has denied your application to register the referenced
pesticide product in New York State.
     The Department has reviewed all of the information submitted in
support of this registration application, and has determined that the
proposed labeled use of this pesticide product as an indoor/outdoor
termiticide may result in deterioration of groundwater resources and
cause adverse human health effects in New York State.
      On February 24, 1994, staff from this Department and the New York
State Department of Health participated in a teleconference with
representatives of FMC Corporation to discuss technical problems
regarding groundwater and health concerns for the proposed use of this
pesticide product. After full consideration of the technical responses
provided by FMC Corporation, the Department continues to have concern
about the potential impacts of the referenced formulated product on
groundwater/drinking water and indoor air quality in New York State.
     Two field dissipation studies submitted by FMC Corporation tested
mobility of bifenthrin, the active ingredient in Biflex TC. In both
studies, bifenthrin was broadcast onto the soil surface (as a foliar
spray) at the 2.0 pounds/acre rate. Soil samples were taken at two
depths (0-6, 6-12 inches) on each sampling date for the 360-day duration
of each study. Bifenthrin was detected in almost all samples taken at
the 0-6 inch sampling depth. Residue levels were consistently lower at
the 6-12 inch sampling depth. However, no sampling below the 12-inch
depth was performed in either field dissipation study.
     The field dissipation studies, we believe, are inadequate to assess
the environmentaI fate of the product for several reasons: the
application rates used are too low (2.0 vs. 4.0 pounds/acre for treating
a typical house foundation), the application methods do not represent
typical termiticide uses (foliar, aboveground spraying vs. subsoil
injection), and test plots were not sampled at realistic soil depths
typical for commercial usage (12.0 inches. vs. 6.0 feet.).
     Additionally, top soils typically contain more organic matter
content (for adsorption) and higher populations of microorganisms (for
degradation) than do subsoils. Therefore, bifenthrin may be
significantly more mobile in subsoils. Added to this concern is the fact
that bifenthrin can persist in the soil for a year or more (even at the
2.0 pounds/acre rate), and the likelihood is that individual water
supply wells may-be located in close proximity to many termiticide
     The data submitted to date does not adequately define the leaching
characteristics of bifenthrin. Since Biflex TC can be applied down to
the level of foundation footings, the question of whether Biflex TC
would leach subsequent to subsurface application needs to be addressed.
In addition, there is a potential for the solvents in Biflex TC to
contaminate groundwater. They are mobile and the finished Biflex TC
emulsion contains more aromatics than bifenthrin.
     There are no chemical-specific federal or state drinking water or
groundwater standards for bifenthrin or "xylene range aromatics." Based
on its chemical structure, bifenthrin falls under the 50 µg/L New York
State drinking water standard for an "unspecified organic contaminant"
(10 NYCRR Part 5, Public Water Systems).
     However, a specific drinking water standard of 10 µg/L can be
derived for bifenthrin using the United States Environmental Protection
Agency (USEPA) oral reference dose (USEPA IRIS, 1993) and USEPA
procedures for Group C carcinogens (Federal Register, 55: 30374, July
25, 1990). This value could also be considered a potential groundwater
standard. xylene (as well as benzene and other alkyl-substituted
benzenes) is a "principal organic contaminant" and has a New York State
drinking water/groundwater standard of 5 µg/L (10 NYCRR Part 5, Public
Water Systems; 6 NYCRR Part 702, Water Quality Regulations).
     The formulation for Biflex TC contains 64.3 percent organic
solvents, 34.3 percent of which are xylene range aromatic hydrocarbons.
Evidence indicates that high levels of exposure to xylene and other
petroleum compounds are possible for extended periods after application
of Biflex TC.
     FMC Corporation conducted a short-term air monitoring study to
assess indoor air impacts of Biflex TC to 15 homes in New Jersey,
Pennsylvania, Florida, and Georgia. The amount of bifenthrin applied to
each home ranged from 227-1361 grams. Measurements in air were taken the
day before, the day of (during application), and the day after Biflex TC
application. Some homes were sampled at one or two additional time
points after treatment, but the sampling time varied from 2-162 days.
     Although the data indicate that bifenthrin should not have long-
term impacts on indoor air, they raise significant concerns about
exposure to the more volatile solvent components of the product. When
the homes were analyzed for volatile aromatic hydrocarbons (calculated
as xylene), concentrations as high as 9.03 mg/m**3 were detected on the
day of treatment and 22.2 mg/m**3 on the day after treatment.
     No follow-up sampling was conducted in the homes where the highest
levels were detected. Follow-up samples were taken two to eight days
after applications in only four homes. Levels as high as 3.13 mg/m**3 were
detected. No samples were taken beyond eight days. Background
concentrations of xylene were reportedly 0.13, 0.22, and 10.6 mg/m**3 in
three of the homes; (typical background concentrations of xylene are
only 0.025-0.05 mg/m**3). No xylene was detected on the day of treatment
in the home with the highest (10.6 mg/m**3) background concentration.
     FMC Corporation provided no explanation for the high background
levels or why xylene was not detected in one home on the day of
treatment. Possible explanations include improper preparation of the
study home, switched samples, recording errors, or analytical problems.
     Because of the poor study design, we believe that the submitted
study is inadequate to measure indoor impacts in treated homes. The
Biflex TC study was compared to a previously submitted indoor air
monitoring study for the registration of similar pesticide product,
Demon TC (EPA Reg. No. 10182-107). The Demon TC study, which used
Dragnet TC as a surrogate, reported concentrations of the active
ingredient and aromatic range hydrocarbons (xylene) in air, carpet
swatch, and surface wipe samples from nine treated homes at five time
points before, during, and up to one month after application. The Biflex
TC study does not address levels of bifenthrin and xylene in carpets and
on surfaces, and the variable sampling intervals make it impossible to
assess air concentrations over time.
     Should FMC Corporation consider resubmitting an application to
register Biflex TC, the above-mentioned concerns must be addressed. As
was discussed in the February 24 meeting, a subsoil degradation study,
the type of which you are currently undertaking, may provide the data
necessary to characterize the fate of bifenthrin when applied to
subsoils. Reformulation of Biflex TC with a different solvent system
that reduces the percentage of volatile organic compounds, as has been
done with other termiticides, could significantly reduce our concerns
about indoor air impacts.
     The Department is aware that no criteria exist for studies designed
to assess groundwater impacts for termiticides. Prior to FMC
Corporation's initiation of any studies to fulfill identified data gaps,
the Department will entertain a technical meeting with FMC Corporation
so that a consensus on study protocol and/or reformulation can be
     Please call Ms. Maureen Serafini, of my staff, at (518) 457-7446 if
you have any questions.
                             Norman H. Nosenchuck, P.E.
                             Division of Hazardous Substances
cc:  N. Kim  - NYS Dept. of Health
     D. Rapp - NYS Dept. of Agriculture and Markets
     D. Rutz - Cornell University