Metaflumizone (also known as BAS 320 I)
(E- and Z-Isomer)

CAS No. 139968-49-3


Return to Metaflumizone Adverse Effects

ACTIVITY: Insecticide (unclassified)

CAS Name: 2-[2-(4-cyanophenyl)-1-[3-(trifluoromethyl)phenyl]ethylidine]-N-[4-

US EPA tolerances: mixture comprising E- and Z-Isomer:
4-(2E)-2-([4-(trifluoromethoxy) anilino]carbonylhydrazono)-2-[3-(trifluoromethyl) phenyl]ethylbenzonitrile and 4-(2Z)-2-([4-(trifluoromethoxy)anilino]carbonyl hydrazono)-2-[3-(trifluoromethyl) phenyl]ethylbenzonitrile


EPA lists the chemical name for BAS 320 I as:
4-{(2E)-2-({[4-(trifluoromethoxy)anilino]carbonyl{time} hydrazono)-2-[3-(trifluoromethyl)phenyl]ethyl{time}
benzonitrile - CAS No. 139968-49-3

4-{(2Z)-2-({[4-(trifluoromethoxy)anilino]carbonyl{time} hydrazono)-2-
[3-(trifluoromethyl) phenyl]ethyl{time} benzonitrile - CAS No. 139968-49-3

Structure for CAS Name:

Adverse Effects:

Body Weight Decrease

Regulatory Information
(only comprehensive for the US)
US EPA Registered: Pending
Other Information
Molecular Formula: C24H16F6N4O2
Entry Year: October 2004 
Other Name(s): BAS 320 I
Manufacturer: BASF
Of special interest:
2006. Summary of toxicology data. California EPA.
The public first heard of this pesticide in October 2004 when it was announced at the website of the Compendium of Pesticide Common Names. Soon after, on Oct. 27, BASF petitioned US EPA for pesticide tolerances on food.

US Federal Register
Date Published Docket Identification Number Details
May 2, 2007 EPA-HQ-OPP-2007-0305 Receipt of Application for Emergency Exemption, Solicitation of Public Comment.
EPA has received a specific exemption request from the Georgia Department of Agriculture to use the pesticide metaflumizone to treat up to 31,000 acres of Brassica leafy vegetables to control the diamondback moth. The Applicant proposes the use of a new chemical which has not been registered by EPA. Therefore, EPA is soliciting public comment, on or before June 1, 2007, before making the decision whether or not to grant the exemption. As part of this request, the Applicant asserts that the available alternative controls are no longer providing adequate control, and states that resistance to some of them may be developing. The Applicant claims that another control chemical is needed to use in rotation with registered materials, to maintain season long control of the diamondback moth in these crops, and that without adequate control, significant economic losses will be suffered. The Applicant proposes to make no more than 4 applications of metaflumizone, at a rate of 0.25 lb. active ingredient per acre (no more than 1.0 lbs. a.i. total), on up to 31,000 acres of Brassica leafy vegetables (including but not limited to cabbage, collard greens, mustard greens, kale) and turnip greens, in Georgia, for use year round, resulting in use of up to a total of 31,000 lbs. a.i. total.
Jan 23, 2006 EPA-HQ-OPP-2005-0302

BASF. Notice of Filing of a Pesticide Petition for the Establishment of Regulations for the Residues of the Insecticide Metaflumizone in or on Food and Feed Commodities.  
New Tolerance. PP 5F6944. BASF Corporation, P.O. Box 13528, Research Triangle Park, NC 27709, proposes to establish tolerances for residues of the insecticide
(mixture comprising (E- and Z-Isomer) 4-(2E)-2-([4-(trifluoromethoxy) anilino]carbonylhydrazono)-2-[3-(trifluoromethyl) phenyl]ethylbenzonitrile and 4-(2Z)-2-([4-(trifluoromethoxy)anilino]carbonyl hydrazono)-2-[3-(trifluoromethyl) phenyl]ethylbenzonitrile) in or on

cotton, seed
cotton, gin trash
cattle and poultry, meat
cattle and poultry, fat
kidney and liver, meat byproducts

BASF Analytical Method No. 531/0 was developed to determine residues of metaflumizone (E- and Z-Isomer) and its metabolites (M320I04 and M320I23), the residues of concern in plants and in crop matrices. In this method, residues of metaflumizone are extracted from plant matrices with methanol/water (70:30; v/v) and then partitioned into dichloromethane. For oily matrices, the residues are extracted with a mixture of isohexane/acetonitrile (1:1; v/v). For animal matrices, a method was developed to determine the residues of metaflumizone (E-and Z-Isomer), the residues of concern. For clean-up, a liquid/liquid partition against dichloromethane is used. The final determination of metaflumizone is performed by using HPLC-MS-MS.

Pursuant to 40 CFR 180.7(f), a summary of the petition included in this notice, prepared by the petitioner along with a description of the analytical method available for the detection and measurement of the pesticide chemical residues is available on EPA's Electronic Docket at To locate this information on the home page of EPA's Electronic Docket, select ``Quick Search'' and type the OPP docket ID number EPA-HQ-OPP-2005-0302 for the pesticide petition (as specified in Unit I.B.1.) in the search field. Once the search has located the docket, clicking on the ``Docket ID'' will bring up a list of all documents in the docket for the pesticide including the petition summary.

Oct 27, 2004 OPP-2004-0273 BASF. BAS 320 I: Pesticide tolerance petition 4F6839; in or on the raw agricultural commodity
Commodity Parts Per Million

tuberous and corm vegetables
(crop subgroup 1-C)

This group includes:
arracacha arrowroot artichoke, chinese artichoke, jerusalem canna, edible
cassava chayote root chufa dasheen ginger leren potato potato culls potato granules flakes potato peel, wet potato processed potato waste potato, specialty sweet potato tanier turmeric yam bean yam, true


leafy vegetables
(crop group 4)

This group includes:
amaranth, leafy arugula cardoon celery celery, chinese celtuce chervil chervil, fresh leaves chrysanthemum, edible leaved chrysanthemum, garland corn salad cress, garden cress, upland dandelion, leaves dock endive fennel, florence fennel, florence, fresh leaves and stalk kale, sea lettuce, head lettuce, leaf orach orach, leaves parsley parsley, leaves purslane, garden purslane, winter radicchio rhubarb spinach spinach, chinese spinach, new zealand spinach, vine swiss chard tampala vegetable, leafy vegetable, leafy, except brassica, group


head and stem brassica
(crop subgroup 5-A)

This group includes:
broccoli, cavalo broccoli, chinese brussels sprout cabbage cabbage, chinese mustard cabbage, chinese napa cauliflower cavalo broccolo kohlrabi


leafy brassica greens
(crop subgroup 5-B)

This group includes:
broccoli raab cabbage, chinese bok choy collards kale mizuna mustard greens mustard spinach
rape greens


fruiting vegetables
(crop group 8)

This group includes:
chili, postharvest
eggplant groundcherry pepino pepper pepper, bell pepper, nonbell pepper, nonbell, sweet tomatillo tomato tomato, concentrated products tomato, dried pomace tomato, paste tomato, puree tomato, wet pomace vegetable, fruiting vegetable, fruiting, group


Plant metabolism. In three plant metabolism studies (cabbage, tomato and cotton), the major component of the residue was BAS 320 I (E- and Z-isomers). The major degradate was the ketone, M320I04 and an oxidized and cyclized metabolite, M320I23, was present in lesser amounts. These four compounds were defined as the residues of concern
Genotoxicty ... there was a positive result for a statistically increased number of structurally aberrant metaphases in the chromosomes, which indicates clastogenic potential under in vitro conditions, this result was only observed without metabolic activation cytogenicity study with V79 cells. ... it has also been recognized by EPA that more weight should be placed on in vivo systems than in vitro systems as expressed in the Agency's weight of evidence for genotoxic evaluation of a chemical included in the ``Guidelines for Mutagenicity Risk Assessment'' (Federal Register, September 24, 1986, Vol. 51: 34006-34012) ... based on the weight of the evidence presented above, BAS 320 I does not pose a genotoxic concern....
Reproductive and developmental toxicity. ...
a 2-generation reproduction toxicity study in Wistar rats by oral gavage administration. Originally, the highest dose tested (HDT) by oral gavage was 75 mg/kg b.w./day, which induced both excessive maternal toxicity (very high incidences of poor general health in females during premating, gestation, and lactation; and statistically decreased food consumption, body weights, and body weight gain) as well as excessive developmental toxicity (statistically impaired pup body weights and body weight gain), which altogether resulted in high pup mortality. Consequently, a meaningful assessment of the potential reproductive toxicity of the test compound at this excessively toxic dose level was not possible. Thereafter, for the next two successive parental generations of rats, which were originally derived from the parents treated at 75 mg/kg b.w./day, the HDT was 50 mg/kg b.w./day. Subsequently, the no observable adverse effect level (NOAEL) for parental toxicity was 20 mg/kg b.w./day, based on the following effects for females at 50 mg/kg b.w./day (HDT for two consecutive generations) increased incidences of poor general health in females during premating, gestation, and lactation; 3 of 25 dams with complete litter losses; and statistically significantly reduced body weights during premating, gestation, and lactation. The NOAEL for offspring/pup toxicity was 20 mg/kg b.w./day, based on a slight increased incidence of pup mortality at 50 mg/kg b.w./day. Whereas the NOAEL for fertility in this study was 50 mg/kg b.w./day (HDT for two generations), the NOAEL for reproductive performance was considered to be 20 mg/kg b.w./day, based on 3 of 25 dams with complete litter losses, of which 2 of these 3 dams had indications of poor nursing for their first generation of pups.
In a developmental (teratology) toxicity study in the Wistar rat, the results indicated that the NOAEL for maternal toxicity was 40 mg/kg b.w./day, based on statistically decreased food consumption and body weight gains at 120 mg/kg b.w./day (HDT). The NOAEL for fetal (prenatal) /developmental toxicity was 120 mg/kg b.w./day (HDT).
In a developmental (teratology) toxicity study in the Himalayan rabbit, the results indicated that the NOAEL for maternal toxicity was 100 mg/kg b.w./day, based on several clinical symptoms of toxicity (including ataxia and poor general state) occurring in 4 of 25 does at 300 mg/kg b.w./day, for which 2 of these 4 does had abortions prior to being sacrificed early, with a third doe at 300 mg/kg b.w./day being sacrificed moribund. Similarly, the NOAEL for fetal (prenatal)/developmental toxicity was 100 mg/kg b.w./day, based on slightly decreased mean fetal body weights as well as an increased rate for a certain skeletal variation, namely incomplete ossification of sternabrae.
Chronic toxicity. In the Sprague-Dawley rat, treatment by oral gavage with BAS 320 I for a 2-year chronic duration resulted in dose-related increased incidences of hepatocellular centrilobular hypertrophy in the livers of males and females at 60 mg/kg b.w./day and at 300/200 mg/kg b.w./day and hepatocellular basophilic alteration in males at 60 and 300 mg/kg b.w./day. (Note: Beginning the first day of Week 3, the dose level of the high-dose females was lowered from 300 to 200 mg/kg b.w./day, due to an adverse effect of -71% decreased body weight gain as compared to controls.)
In the beagle dog, treatment via gelatin capsules with BAS 320 I for a 12-month chronic duration resulted in reduced body weight gain and/or decreased food consumption in several dogs at 30 mg/kg b.w./day and slightly decreased mean MCHC at 30 mg/kg b.w./day ... For BAS 320 I, the lowest NOAEL for chronic toxic effects is 12 mg/kg b.w./day from the 12-month dog study.
Subchronic toxicity study with Z-Isomer. In the Sprague-Dawley rat, treatment by oral gavage with the Z-isomer of BAS 320 I for a
(90-day) duration resulted in impaired body weight gain only in females at the mid-dose (300 mg/kg b.w./day) and the high-dose (1,000 mg/kg b.w./day), as compared to controls. Several microscopic changes were observed in female animals at these two dose levels, but all morphologic changes were regarded to be indirect effects of the impaired body weight gain.
Secondary residues from meat, milk, and eggs were not included in this assessment since the proposed crops are only considered for human consumption with the exception of processed potato commodities being potentially utilized in animal feed. Animal feeding studies were not required on potatoes based on results of residues of BAS 320 I and its metabolites (M320I04 and M320I23) in unwashed potatoes. Following an application rate 18 times the proposed seasonal rate, residues in potatoes were at or below the limit of quantitation (LOQ) and thus the proposed tolerance level was set at the LOQ and no feeding studies were needed.
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