PMEP Home Page --> Pesticide Active Ingredient Information --> Insecticides and Miticides --> cadusafos (Rugby) to cyromazine (Larvadex) --> chlorfenapyr --> chlorfenapyr Pesticide Petition Filing 3/98

chlorfenapyr Pesticide Petition Filing 3/98

[Page 14926-14936]
>From the Federal Register Online via GPO Access []



[PF-799; FRL-5579-6]

Notice of Filing of Pesticide Petitions

AGENCY: Environmental Protection Agency (EPA).

ACTION: Notice.


SUMMARY: This notice announces the initial filing of pesticide 
petitions proposing the establishment of regulations for residues of 
certain pesticide chemicals in or on various food commodities.
DATES: Comments, identified by the docket control number PF-799, must 
be received on or before April 27, 1998.
ADDRESSES: By mail submit written comments to: Public Information and 
Records Integrity Branch, Information Resources and Services Division 
(7506C), Office of Pesticides Programs, Environmental Protection 
Agency, 401 M St., SW., Washington, DC 20460. In person bring comments 
to: Rm. 1132, CM #2, 1921 Jefferson Davis Highway, Arlington, VA.
    Comments and data may also be submitted electronically by following 
the instructions under ``SUPPLEMENTARY INFORMATION.'' No confidential 
business information should be submitted through e-mail.
    Information submitted as a comment concerning this document may be 
claimed confidential by marking any part or all of that information as 
``Confidential Business Information'' (CBI). CBI should not be 
submitted through e-mail. Information marked as CBI will not be 
disclosed except in accordance with procedures set forth in 40 CFR part 
2. A copy of the comment that does not contain CBI must be submitted 
for inclusion in the public record. Information not marked confidential 
may be disclosed publicly by EPA without prior notice. All written 
comments will be available for public inspection in Rm. 1132 at the 
address given above, from 8:30 a.m. to 4 p.m., Monday through Friday, 
excluding legal holidays.

FOR FURTHER INFORMATION CONTACT: The product reviewer listed in the 
table below:

                                   Office location/                     
        Product Manager            telephone number          Address    
Ann Sibold....................  Rm. 212, CM #2, 703-    1921 Jefferson  
                                 305-6502, e-            Davis Hwy,     
                                 mail:sibold.ann@epama   Arlington, VA  
Joseph M. Tavano..............  Rm. 214, CM #2, 703-    Do.             
                                 305-6411, e-mail:                      

SUPPLEMENTARY INFORMATION: EPA has received pesticide petitions as 
follows proposing the establishment and/or amendment of regulations for 
residues of certain pesticide chemicals in or on various food 
commodities under section 408 of the Federal Food, Drug, and Comestic 
Act (FFDCA), 21 U.S.C. 346a. EPA has determined that these petitions 
contain data or information regarding the elements set forth in section 
408(d)(2); however, EPA has not fully evaluated the sufficiency of the 
submitted data at this time or whether the data supports granting of 
the petition. Additional data may be needed before EPA rules on the 
    The official record for this notice of filing, as well as the 
public version, has been established for this notice of filing under 
docket control number [PF-799] (including comments and data submitted 
electronically as described below). A public version of this record, 
including printed, paper versions of electronic comments, which does 
not include any information claimed as CBI, is available for inspection 
from 8:30 a.m. to 4 p.m., Monday through Friday, excluding legal 
holidays. The official record is located at the address in 
``ADDRESSES'' at the beginning of this document.
    Electronic comments can be sent directly to EPA at:

    Electronic comments must be submitted as an ASCII file avoiding the 
use of special characters and any form of encryption. Comment and data 
will also be accepted on disks in

[[Page 14927]]

Wordperfect 5.1 file format or ASCII file format. All comments and data 
in electronic form must be identified by the docket number (insert 
docket number) and appropriate petition number. Electronic comments on 
notice may be filed online at many Federal Depository Libraries.

List of Subjects

    Environmental protection, Agricultural commodities, Food additives, 
Feed additives, Pesticides and pests, Reporting and recordkeeping 

    Dated: March 19, 1998

Peter Caulkins,

Acting Director, Registration Division, Office of Pesticide Programs.

Summaries of Petitions

    Petitioner summaries of the pesticide petitions are printed below 
as required by section 408(d)(3) of the FFDCA. The summaries of the 
petitions were prepared by the petitioners and represent the views of 
the petitioners. EPA is publishing the petition summaries verbatim 
without editing them in any way. The petition summary announces the 
availability of a description of the analytical methods available to 
EPA for the detection and measurement of the pesticide chemical 
residues or an explanation of why no such method is needed.

1. American Cyanamid Company

PP 6F4623

    EPA has received a pesticide petition (PP 6F4623) from American 
Cyanamid Company, P.O. Box 400, Princeton, NJ 08543-0400, proposing 
pursuant to section 408(d) of the Federal Food, Drug and Cosmetic Act, 
21 U.S.C. 346a(d), to amend 40 CFR part 180 by establishing a tolerance 
of 0.5 ppm for residues of 4-bromo-2-(4-chlorophenyl)-1-(ethoxymethyl)-
5-(trifluoromethyl)-1-pyrrole-3-carbonitrile, (chlorfenapyr) in or on 
the raw agricultural commodity citrus. As citrus processed commodities 
fed to food animals may be transferred to milk and edible tissues, 
tolerances are also proposed for the following ruminant food items: 
milk at 0.01 parts per million (ppm); milk fat at 0.15 ppm; meat at 
0.01 ppm; and meat by-products (including fat) at 0.10 ppm.
    The proposed analytical method is capillary gas chromatography 
using an electron capture detector. EPA has determined that the 
petition contains data or information regarding the elements set forth 
in section 408(d)(2) of the FFDCA; however, EPA has not fully evaluated 
the sufficiency of the submitted data at this time or whether the data 
supports granting of the petition. Additional data may be needed before 
EPA rules on the petition.

A. Residue Chemistry

    1. Plant metabolism. The nature of the residues of chlorfenapyr in 
plants is adequately understood and the residue of concern in citrus 
consists of the parent molecule. Expressed on a whole basis, the parent 
compound accounted for 56-75% of the total radioactive residue (TRR), 
98% of which was associated with the external rinse and peel.
    2. Analytical method. The GC analytical method, M2284, which is 
proposed as the enforcement method for the residues of chlorfenapyr in 
citrus, has a limit of detection (LOD) of 0.01 ppm (0.025 ppm for 
juice) and a limit of quantitation (LOQ) of 0.05 ppm.
    3. Magnitude of residues. Extensive citrus field trials have been 
conducted over multiple growing seasons in all major citrus growing 
regions of the US. The results of these studies indicate that at the 
highest proposed use rate of 1.05 lbs ai/A, the maximum expected 
chlorfenapyr residues are 0.4 ppm in oranges, 0.38 ppm in lemons and 
0.27 ppm in grapefruit in/on citrus samples harvested 7 days following 
the last application. These field trial data are adequate to support 
the proposed tolerance of 0.5 ppm in/on citrus harvested 7-days 
following the last application. The results of processing studies 
indicate that chlorfenapyr residues do not concentrate in molasses and 
juice. The actual concentration factors in dried pulp (2.4x) and citrus 
oil (70x) are well below the maximum theoretical concentration factors 
for these commodities. Although citrus oil is not considered to be a 
ready-to-eat item and is not expected to contribute to the dietary 
exposure, a tolerance at 35 ppm (0.5 ppm x 70) is proposed for 
enforcement purposes.

B. Toxicological Profile

    1. Acute toxicity. Based on the EPA's toxicity category criteria, 
the acute toxicity category for chlorfenapyr technical is Category II 
or moderately toxic (signal word WARNING) and the acute toxicity 
category for the 2SC formulation is Category III or slightly toxic 
(signal word CAUTION). Males appear to be more sensitive to the effects 
of chlorfenapyr than females. The acute toxicity profile indicates that 
absorption by the oral route appears to be greater than by the dermal 
route. The following are the results from the acute toxicity tests 
conducted on the technical material:
    i. Rat Oral LD<INF>50</INF>: 441/1152 milligram/kilograms (mg/kg) 
bwt.(M/F) -- Tox. Category II
    ii. Rabbit Dermal LD<INF>50</INF>: >2,000 mg/kg bwt.(M/F) -- Tox. 
Category III
    iii. Acute Inhal. LC<INF>50</INF>: 0.83/>2.7 mg/L (M/F) -- Tox. 
Category III
    iv. Eye Irritation: Moderately Irritating -- Tox. Category III
    v. Dermal Irritation: Non-Irritating -- Tox. Category IV
    vi. Dermal Sensitization: Non-Sensitizer -- Non Sensitizer
    vii. Acute Neurotoxicity: NOEL 45 mg/kg bwt. -- Not An Acute 
    2. Genotoxicty. Chlorfenapyr technical (94.5% a.i.) was examined in 
a battery ofin vitro and in vivo tests to assess its genotoxicity and 
its potential for carcinogenicity. These tests are summarized below.
    Microbial/Microsome Mutagenicity Assay: Non-mutagenic
    Mammalian Cell CHO/HGPRT Mutagenicity Assay: Non-mutagenic
    In Vivo Micronucleus Assay: Non-genotoxic
    In Vitro--Chromosome Aberration Assay in CHO: Non-clastogenic
    In Vitro--Chromosome Aberration Assay in CHLC: Non-clastogenic
    Unscheduled DNA Synthesis (UDS) Assay: Non-genotoxic.
    3. Reproductive and developmental toxicity. Chlorfenapyr is neither 
a reproductive or developmental toxicant and is not a teratogenic agent 
in the Sprague-Dawley rat or the New Zealand white rabbit. This is 
demonstrated by the results of the following studies:
    Rat Oral Teratology -- No-Observed-Effect-Level (NOEL) for maternal 
toxicity 25 mg/kg bwt./day and NOEL for fetal/develop. toxicity 225 
milligram/kilograms body weight/day (mg/kg bwt./day)
    Rabbit Oral Teratology -- NOEL for maternal toxicity 5 mg/kg bwt./
day and NOEL for fetal/develop. toxicity 30 mg/kg bwt./day
    Rat 2-Generation Reproduction -- NOEL for parental toxicity /growth 
and offspring development 60 ppm (5 mg/kg bwt./day)
NOEL for reproductive performance 600 ppm (44 mg/kg bwt./day).
    4. Subchronic toxicity. The following are the results of the 
subchronic toxicity tests that have been conducted with chlorfenapyr:
    28-Day Rabbit Dermal -- NOEL 100 mg/kg bwt./day
    28-Day Rat Feeding -- NOEL >600 ppm (< 71.6 mg/kg bwt./day)
    28-Day Mouse Feeding -- NOEL >160 ppm (<32 mg/kg bwt./day)
    13-Week Rat Dietary -- NOAEL 150 ppm (11.7 mg/kg bwt./day)

[[Page 14928]]

    13-Week Mouse Dietary -- NOEL 40 ppm (8.2 mg/kg bwt./day)
    13-Week Dog Dietary -- NOAEL 120 ppm (4.2 mg/kg bwt./day)
    5. Chronic toxicity. Chlorfenapyr is not oncogenic in either 
Sprague Dawley rats or CD-1 mice and is not likely to be carcinogenic 
in humans. The following are the results of the chronic toxicity tests 
that have been conducted with chlorfenapyr:
    1-Year Neurotoxicity in Rats -- NOEL 60 ppm (2.6/3.4 mg/kg bwt./day 
    1-Year Dog Dietary -- NOEL 120 ppm (4.0/4.5 mg/kg bwt./day M/F)
    24-Month Rat Dietary -- NOEL for Chronic Effects 60 ppm (2.9/3.6 
mg/kg bwt./day M/F) and NOEL for Oncogenic Effects 600 ppm (31/37 mg/kg 
bwt./day M/F)
    18-Month Mouse Dietary -- NOEL for Chronic Effects 20 ppm (2.8/3.7 
mg/kg bwt./day M/F) and NOEL for Oncogenic Effects 240 ppm (34.5/44.5 
mg/kg bwt./day M/F)
    6. Animal metabolism. A metabolism study was conducted in Sprague 
Dawley rats at approximately 20 and 200 mg/kg bwt. using radiolabeled 
chlorfenapyr. Approximately 65% of the administered dose was eliminated 
during the first 24 hours (62% in feces and 3% in urine) and by 48 
hours following dosing, approximately 85% of the dose had been excreted 
(80% in feces and 5% in urine). The absorbed chlorfenapyr-related 
residues were distributed throughout the body and detected in tissues 
and organs of all treatment groups. The principal route of elimination 
was via feces, mainly as unchanged parent plus minor N-dealkylated, 
debrominated and hydroxylated oxidation products.
    The metabolic pathway of chlorfenapyr in the laying hen and the 
lactating goat was also similar to that in laboratory rats.
    7. Metabolite toxicology. The parent molecule is the only moiety of 
toxicological significance which needs regulation in plant and animal 
    8. Endocrine effects. Collective organ weights and 
histopathological findings from the 2-generation rat reproduction 
study, as well as from the subchronic and chronic toxicity studies in 
two or more animal species, demonstrate no apparent estrogenic effects 
or effects on the endocrine system. There is no information available 
which suggests that chlorfenapyr would be associated with endocrine 

C. Aggregate Exposure

    1. Dietary exposure-- i. Food. For purposes of assessing the 
potential dietary exposure, a Theoretical Maximum Residue Contribution 
(TMRC) has been calculated from the tolerance of chlorfenapyr in/on 
citrus at 0.5 ppm. This exposure assessment is based on very 
conservative assumptions, namely 100% of all citrus is treated with 
chlorfenapyr and that the residues of chlorfenapyr in citrus are at the 
tolerance level. Although there are no other established US permanent 
tolerances for chlorfenapyr, a petition for a permanent tolerance at 
0.5 ppm in cottonseed is pending at the Agency. Therefore, the dietary 
exposures to residues of chlorfenapyr in or on food will be limited to 
residues in cottonseed, citrus and food and feed items derived from 
them. As dried citrus pulp is a dairy and beef cattle feed item, a cold 
feeding study with dairy cattle was conducted. Since this study 
demonstrated that measurable residues of chlorfenapyr may occur in 
milk, meat and meat by products, appropriate residue tolerances for 
these items are proposed. The contribution of the citrus tolerances 
alone to the daily consumption uses only 0.23% of the reference dose 
(RfD) for the overall US population. The combined contributions of the 
citrus and the pending cottonseed tolerances to the daily consumption 
uses less than 1% (actual 0.85%) of the reference dose for the overall 
US population and less than 3% (actual 2.23%) and less than 1% (actual 
0.89%) of the reference doses for children aged 1-6 and for non-nursing 
infants, respectively.
    ii. Drinking water. There is no available information about 
chlorfenapyr exposures via levels in drinking water. There is no 
concern for exposure to residues of chlorfenapyr in drinking water 
because of its extremely low water solubility (120 ppb at 25 deg.). 
Chlorfenapyr is also immobile in soil and does not leach because it is 
strongly adsorbed to all common soil types. In addition, the label 
explicitly prohibits applications near aquatic areas
    There is a reasonable certainty that no harm will result from 
dietary exposure to chlorfenapyr, because dietary exposure to residues 
on food will use only a small fraction of the (RfD) (including exposure 
of sensitive subpopulations), and exposure through drinking water is 
expected to be insignificant.
    2. Non-dietary exposure. There is no available information 
quantifying non-dietary exposure to chlorfenapyr. However, based on the 
physico-chemical characteristics of the compound, the proposed use 
pattern and available information concerning its environmental fate, 
non-dietary exposure is expected to be negligible. The vapor pressure 
of chlorfenapyr is less than 1 x 10<SUP>-7</SUP> mm of Hg; therefore, 
the potential for non-occupational exposure by inhalation is 
insignificant. Moreover, the current proposed registration is for 
outdoor, terrestrial uses which severely limit the potential for non-
occupational exposure.

D. Cumulative Effects

    The pyrrole insecticides represent a new class of chemistry with a 
unique mechanism of action. The parent molecule, AC 303,630 is a pro-
insecticide which is converted to the active form, CL 303,268, via 
rapid metabolism by mixed function oxidases (MFOs). The active form 
uncouples oxidative phosphorylation in the insect mitochondria by 
disrupting the proton gradient across the mitochondrial membrane. The 
production of ATP is inhibited resulting in the cessation of all 
cellular functions. Because of this unique mechanism of action, it is 
highly unlikely that toxic effects produced by chlorfenapyr would be 
cumulative with those of any other pesticide chemical.
    In mammals, there is a lower titer of MFOs, and chlorfenapyr is 
metabolized by different pathways (including dehalogenation, oxidation 
and ring hydroxylation) to other polar metabolites without any 
significant accumulation of the potent uncoupler, CL--303,268. In the 
rat, approximately 85 % of the administered dose is excreted in the 
feces within 48-hours, thereby reducing the levels of AC 303,630 and CL 
303,268 that are capable of reaching the mitochondria. This 
differential metabolism of AC 303,630 to CL 303,268 in insects versus 
to other polar metabolites in mammals is responsible for the selective 
insect toxicity of the pyrroles.

E. Safety Determination

    1. U.S. population. The RfD of 0.03 mg/kg bwt./day for the residues 
of chlorfenapyr in citrus is calculated by applying a 100-fold safety 
factor to the overall NOEL of 3 mg/kg bwt./day. This NOEL is of based 
on the results of the chronic feeding studies in the rat and mouse and 
the 2-generation reproduction study in the rat (see Item 2). The TMRC 
for the proposed tolerances in citrus alone, (0.0000692 mg/kg bwt./
day), will utilize only 0.23% of the RfD for the general U.S. 
population and the combined TMRC for the proposed chlorfenapyr 
tolerances in cottonseed, citrus, milk and meat (0.0002558 mg/kg bwt./
day) will utilize approximately 0.85% of the RfD for the general U.S. 
    2. Infants and children. The TMRC in milk consumed by a non-nursing 

[[Page 14929]]

(>1-year of age) is 0.0002435 mg/kg bwt./day. The combined tolerances 
will use less than 1% (actual 0.89%) of the RfD for non-nursing 
infants. The TMRC in milk consumed by a child (1-6 years of age) is 
0.0003886 mg/kg bwt./day. The combined TMRC for the proposed 
chlorfenapyr tolerances in cottonseed, citrus meat and milk consumed by 
a child 1-6 years of age is 0.0006708 mg/kg bwt./day, which is less 
than 3% (actual 2.23%) of the RfD. Therefore, the results of the 
toxicology and metabolism studies support both the safety of 
chlorfenapyr to humans based on the intended use as an insecticide-
miticide on citrus and cottonseed and the granting of the requested 
tolerances in cottonseed, citrus, milk, milk fat solids, meat and meat 
    Based on the conservative assumptions used in proposing the above 
tolerances and the absence of other non-dietary routes of exposure to 
chlorfenapyr, and since the calculated exposures are well below 100% of 
the reference dose, there is a reasonable certainty that no harm will 
result from aggregate exposure to residues of chlorfenapyr, including 
all anticipated dietary exposure and all other non-occupational 
exposures. The use of a 100-fold safety factor ensures an acceptable 
margin of safety for both the overall U. S. population as well as 
infants and children. As the toxicology database (reproduction/
developmental and teratology studies) is complete, valid and reliable, 
no additional safety factor is needed.
    The 100-fold margin of safety is adequate to assure a reasonable 
certainty of no harm to infants and children from the proposed use. As 
stated earlier, the NOEL is based on the effects observed in the rat 
and mouse chronic oncogenicity studies, (reduced body weight gains, 
increased globulin and cholesterol values and increased liver weights 
in the rat and reduced body weight gains and vacuolation of white 
matter of the mouse brain), the one-year neurotoxicity study in the 
rat, (reduced body weight gains and vacuolar myelinopathy of the brain 
and spinal cord that is completely reversible following termination of 
treatment and is not associated with any damage to neuronal cell bodies 
or axons; vacuolation of the white matter is a consequence of edema 
(water) formation between the myelin layers which result from the 
unrestricted movement of ions across the cell membranes) and the 2-
generation rat reproduction study, (reduced body weight gains for 
parental animals and reduced pup body weights for the F1 and F2 
litters; however no behavioral changes were observed in either F1 or F2 
offsprings in the 2-generation reproduction study). Moreover, as the 
NOELs for fetal/developmental toxicity are significantly higher than 
those for maternal toxicity, the results indicate that chlorfenapyr is 
neither a developmental toxicant nor a teratogenic agent in either the 
Sprague-Dawley rat or New Zealand White rabbit. Thus, there is no 
reliable information to indicate that there would be a variability in 
the sensitivities of infants and children and adults to the effects of 
exposure to chlorfenapyr.

F. International Tolerances

    Section 408 (b)(4) of the amended FFDCA requires EPA to determine 
whether a maximum residue level has been established for the pesticide 
chemical by the Codex Alimentarius Commission.
    There is neither a Codex proposal, nor Canadian or Mexican 
tolerances/limits for residues of chlorfenapyr in/on citrus. Therefore, 
a compatibility issue is not relevant to the proposed tolerance.

[FR Doc. 98-8065 Filed 3-26-98; 8:45 am]