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NYS DEC Letter - Major Change in Labeling 7/04

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

July 23, 2004


John Abbott, Ph.D.
State Regulatory Affairs
Team Leader
Syngenta Crop Protection, Inc.
P.O. Box 18300
Greensboro, North Carolina 72419-8300

Dear Dr. Abbott:

Re: Major Change in Labeling - New Use for Lambda-cyhalothrin as contained in Impasse Termite System (EPA Reg. No. 100-1125) and Impasse Termite Blocker (EPA Reg. No. 100-1166)

    The New York State Department of Environmental Conservation (Department) has reviewed your applications, received November 5, 2003, to register the pesticide products, Impasse Termite System (EPA Reg. No. 100-1125) and Impasse Termite Blocker (EPA Reg. No. 100-1166) in New York State. These products contain new uses for the active ingredient lambda-cyhalothrin.

    Impasse Termite System (ITS) (EPA Reg. No. 100-1125) is a uniform multilayer polymer sheet consisting of an interior layer of lambda-cyhalothrin insecticide, surrounded on either side by layers of polymers that are impervious to the active ingredient. Impasse Termite System is intended for new construction and is to be installed by trained personnel. Impasse Termite System is installed onto the soil surface before the footings or slab are poured and before the construction of the structure.

    Impasse Termite Blocker (EPA Reg. No. 100-1166), also uniform multilayer polymer sheeting as in the above-mentioned product, is intended for installation around plumbing, electrical, and other utility penetrations before the concrete foundation of the structure is poured. Impasse Termite Blocker is manufactured in multiple sizes to fit over a wide range of utility pipe diameters. Also note that this active ingredient, sold under the trade name Demand CS (EPA Reg. No. 100-1066), is currently registered in New York State for termite control.

    The Department has reviewed the information supplied to date in support of registration of the new use for the active ingredient lambda-cyhalothrin as contained in the pesticide products Impasse Tennite System (EPA Reg. No. 100-1125) and Impasse Termite Blocker (EPA Reg. No. 100-1166).


    The New York State Department of Health (DOH) reviewed the application and supporting data submitted by Syngenta Crop Protection, Inc., to register the pesticide products Impasse Termite System (EPA Reg. No. 100-1125) and Impasse Termite Blocker (EPA Reg. No. 100-1166). Lambda-cyhalothrin is currently registered in the State for use in cattle ear tags, in and around buildings and structures (including termiticide use), on ornamentals and turf, in commercial greenhouses, shadehouses, nursery environments and on various crops.

    Due to the physical nature of the formulated products, a multilayer polymer sheet, these products are not amenable to standard acute toxicity testing. Accordingly, the United States Environmental Protection Agency (USEPA) classified these products as relatively nontoxic on an acute basis by the oral, dermal or inhalation routes of exposure, and also to be nonirritating to the eyes and skin.

    The DOH previously reviewed the toxicity of lambda-cyhalothrin for other pesticide products in 1996 and 2003. Lambda-cyhalothrin was mildly to moderately acutely toxic in laboratory animal studies and caused some toxic effects at low doses in chronic animal feeding studies. This chemical did not cause significant reproductive/developmental effects, but did cause some fetotoxicity. Lambda-cyhalothrin did not cause oncogenic effects and was negative in a number of genotoxicity studies. The USEPA classified lambda-cyhalothrin as a Group D carcinogen--not classifiable as to human carcinogenicity. The USEPA RfD Peer Review Committee derived an oral reference dose (RfD) of 0.001 milligrams per kilogram body weight per day (mg/kg/day) for lambda-cyhalothrin, based on a no-observed-effect-level (NOEL) of 0.1 mg/kg/day from a chronic dog feeding study (ataxia, muscle tremors and convulsions) and an uncertainty factor of 100. A current search to the toxicological literature did not find any significant new information on the toxicity of lambda-cyhalothrin.

    The registrant submitted the results of a 21-day dermal toxicity study and a 21-day inhalation toxicity study on lambda-cyhalothrin, both conducted on rats. Clinical signs of neurotoxicity and decreases in body weight gains were observed in animals of both studies at doses of 50 mg/kg/day (dermal exposure) and 0.88 mg/kg/day (inhalation exposure). The respective NOELS were ten mg/kg/day and 0.08 mg/kg/day.

    The registrant conducted an occupational risk assessment for workers handling and installing the Impasse Termite products at construction sites based on actual measurements of lambda-cyhalothrin exposure. For determining margins of exposure (MOEs), estimated dermal and inhalation exposures were compared to NOELS of ten mg/kg/day and 0.08 mg/kg/day from the 21-day rat dermal toxicity study and the 21-day rat inhalation toxicity study, respectively. The estimated MOEs for workers ranged from about 1,400 to 5,000 for dermal exposure, and was about 500 for the inhalation route of exposure. Generally, the USEPA considers MOEs of 100-fold or greater to provide adequate worker protection.

    There are no chemical-specific federal or State drinking water/groundwater standards for lambda-cyhalothrin. Based on its chemical structure, lambda-cyhalothrin falls under the 50 microgram per liter (ug/L) New York State drinking water standard for "unspecified organic contaminants" (10 NYCRR Part 5, Public Water Systems). Based on the USEPA's oral RfD of 0.001 mg/kg/day and the New York State Department of Environmental Conservation Water Quality Regulation procedures for deriving surface water and groundwater standards and guidance values from non-oncogenic effects (6 NYCRR Part 702.5), an ambient water quality value for lambda-cyhalothrin is 7 ug/L. This value could be used to derive a screening value for comparison to estimate impacts to groundwater and surface water.

    Although toxicological studies on the active ingredient lambda-cyhalothrin indicate that this chemical has some toxic properties, the labeled use of Impasse Termite System and Impasse Termite Blockers should not pose a significant health risk to workers or to occupants of treated structures. A concern for many of the traditional termiticide products is the potential for mixing errors, spills or for the solvent system or the active ingredient to impact indoor air quality. The Impasse products do not pose these concerns. In addition, because they do not contain solvents and are comprised of active ingredient encased in polymer sheets, these products do not pose a significant risk to drinking water sources around treated structures as do some of the traditional termiticides. However, the Impasse Termite Blocker label does not contain a statement requiring workers to wear gloves, as is present on the label for the Impasse Termite System product.

    You have agreed to add the additional PPE statement to wear gloves during application at the next label printing.


    The Department's Division of Fish, Wildlife & Marine Resources' Bureau of Habitat (BOH) reviewed the material submitted to support the registration of Impasse Termite System (EPA Reg. No. 100-1125) and Impasse Termite Blocker (EPA Reg. No.100-1166). They stated that, when used as labeled, the fish and wildlife exposure to lambda-cyhalothrin should be minimal to nonexistent.


    The Department's groundwater staff stated the following:

    Impasse Termite System and Impasse Termite Blocker both contain 0.77% lambda-cyhalothrin as the active ingredient.

Technical Review

Hydrolysis: At pH 5 and pH 7, there is no hydrolysis; however, at pH 9, the hydrolysis half-life is seven days.

Aqueous Photolysis: According to a study summary, after 31 days, 38-44% remained with two major degradates (IRS)-cis-3-(ZE-2-chloro-3,3,3-trifluoroprop-l-enyl)-2,2-dimethylcyclopropane-carboylic acid at 13.4% and 3-phenoxybenzoic acid at 24.5%.

Soil Photolysis: Lambda-cyhalothrin is stable to photolysis on soil. Aerobic Soil Metabolism: According to a study summary, lambda-cyhalothrin aerobically degraded with a half-life of about 30 days.

Anaerobic Soil Metabolism: Lambda-cyhalothrin anaerobically degraded with a half-life of < 30 days.

Column Leaching: Lambda-cyhalothrin and its degradates were immobile in columns of clay loam, loamy sand, coarse sand and peat soils.

Adsorption/Desorption: According to a study summary, lambda-cyhalothrin was rapidly and extensively adsorbed onto four different soils with Kocs in the range of 100,000-430,000, which is in good agreement with the 150,000 value calculated from the octanol-water partitioning coefficient.

Field Dissipation: In supplemental field dissipation studies, the reported half-lives ranged from 26-40 days. Analysis showed all but one detection was found in the zero- to six-inch depth, and one in the six- to 12-inch depth at days zero and seven posttreatment.

Summary: The active ingredient is encased in a multilayer polymer sheet or boot that is impervious to the active ingredient and is waterproof. The active ingredient is not available to leach to the environment unless the barrier is breached by a sharp object or by a termite. Then the amount available to the environment is very minute and is not expected to cause a negative impact to the groundwater or surface water. The Department concludes that Impasse Termite System (EPA Reg. No. 100-1125) and Impasse Termite Blocker (EPA Reg. No.100-1166) should not have an adverse effect on the health of workers or the general public, the fish and wildlife resources, or the ground and surface water of New York State when used as labeled.

    Therefore, the Department hereby accepts for general use registration in New York State the pesticide products Impasse Termite System (EPA Reg. No. 100-1125) and Impasse Termite Blocker (EPA Reg. No.100-1166).

    Enclosed is your Certificate of Registration and New York State stamped "ACCEPTED" labels.

    If you have any questions, please contact Samuel Jackling, Chief of our Pesticide Product Registration Section, at (518) 402-8768.


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