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Chlorfenapyr (BASF) . July 16, 2003. Petition for pesticide tolerance. Federal Register.


http://www.epa.gov/fedrgstr/EPA-PEST/2003/July/Day-16/p17900.htm


[Federal Register: July 16, 2003 (Volume 68, Number 136)]
[Notices]
[Page 42022-42026]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr16jy03-80]

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ENVIRONMENTAL PROTECTION AGENCY
[OPP-2003-0205; FRL-7312-7]
 
Chlorfenapyr; Notice of Filing a Pesticide Petition to Establish 
a Tolerance for a Certain Pesticide Chemical in or on Food

AGENCY:  Environmental Protection Agency (EPA).
ACTION:  Notice.

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SUMMARY:  This notice announces the initial filing of a pesticide 
petition proposing the establishment of regulations for residues of a 
certain pesticide chemical in or on various food commodities.

DATES:  Comments, identified by docket ID number OPP-2003-0205, must be 
received on or before August 15, 2003.

ADDRESSES:  Comments may be submitted electronically, by mail, or 
through hand delivery/courier. Follow the detailed instructions as 
provided in Unit I. of the SUPPLEMENTARY INFORMATION.

FOR FURTHER INFORMATION CONTACT:  Ann Sibold, Registration Division 
(7505C), Office of Pesticide Programs, Environmental Protection Agency, 
1200 Pennsylvania Ave., NW., Washington, DC 20460-0001; telephone 
number: (703) 305-6502; e-mail address: sibold.ann@epa.gov.

SUPPLEMENTARY INFORMATION:

I. General Information

A. Does this Action Apply to Me?

     You may be potentially affected by this action if you are a 
commercial processor of food, or use pesticides to control pests in 
food processing operations. Potentially affected entities may include, 
but are not limited to:
     Crop production (NAICS 111)
     Animal production (NAICS 112)
     Food manufacturing (NAICS 311)
     Pesticide manufacturing (NAICS 32532)
     This listing is not intended to be exhaustive, but rather provides 
a guide for readers regarding entities likely to be affected by this 
action. Other types of entities not listed in this unit could also be 
affected. The North American Industrial Classification System (NAICS) 
codes have been provided to assist you and others in determining 
whether this action might apply to certain entities. If you have any 
questions regarding the applicability of this action to a particular 
entity, consult the person listed under FOR FURTHER INFORMATION 
CONTACT.

B. How Can I Get Copies of this Document and Other Related Information?

    1. EPA Docket. EPA has established an official public docket for 
this action under docket ID number OPP-2003-0205. The official public 
docket consists of the documents specifically referenced in this 
action, any public comments received, and other information related to 
this action. Although, a part of the official docket, the public docket 
does not include Confidential Business Information (CBI) or other 
information whose disclosure is restricted by statute. The official 
public docket is the collection of materials that is available for 
public viewing at the Public Information and Records Integrity Branch 
(PIRIB), Rm. 119, Crystal Mall #2, 1921 Jefferson Davis Hwy., 
Arlington, VA. This docket facility is open from 8:30 a.m. to 4 p.m., 
Monday through Friday, excluding legal holidays. The docket telephone 
number is (703) 305-5805.
    2. Electronic access. You may access this Federal Register document 
electronically through the EPA Internet under the ``Federal Register'' 
listings at http://www.epa.gov/fedrgstr/.
     An electronic version of the public docket is available through 
EPA's electronic public docket and comment system, EPA dockets. You may 
use EPA Dockets at http://www.epa.gov/edocket/ to submit or view public 
comments, access the index listing of the contents of the official 
public docket, and to access those documents in the public docket that 
are available electronically. Although, not all docket materials may be 
available electronically, you may still access any of the publicly 
available docket materials through the docket facility identified in 
Unit I.B.1. Once in the system, select ``search,'' then key in the 
appropriate docket ID number.
     Certain types of information will not be placed in the EPA 
Dockets. Information claimed as CBI and other information whose 
disclosure is restricted by statute, which is not included in the 
official public docket, will not be available for public viewing in 
EPA's electronic public docket. EPA's policy is that copyrighted 
material will not be placed in EPA's electronic public docket but will 
be available only in printed, paper form in the official public docket. 
To the extent feasible, publicly available docket materials will be 
made available in EPA's electronic public docket. When a document is 
selected from the index list in EPA dockets, the system will identify 
whether the document is available for viewing in EPA's electronic 
public docket. Although, not all docket materials may be available 
electronically, you may still access any of the publicly available 
docket materials through the docket facility identified in Unit I.B. 
EPA intends to work towards providing electronic access to all of the 
publicly available docket materials through EPA's electronic public 
docket.
     For public commenters, it is important to note that EPA's policy 
is that public comments, whether submitted electronically or on paper, 
will be made available for public viewing in EPA's electronic public 
docket as EPA receives them and without change, unless the comment 
contains copyrighted material, CBI, or other information whose 
disclosure is restricted by statute. When EPA identifies a comment 
containing copyrighted material, EPA will provide a reference to that 
material in the version of the comment that is placed in EPA's 
electronic public docket. The entire printed comment, including the 
copyrighted material, will be available in the public docket.
     Public comments submitted on computer disks that are mailed or 
delivered to the docket will be transferred to EPA's electronic public 
docket. Public comments that are mailed or delivered to the docket will 
be scanned and placed in EPA's electronic public docket. Where 
practical, physical objects will be photographed, and the photograph 
will be placed in EPA's electronic public docket along with a brief 
description written by the docket staff.

C. How and to Whom Do I Submit Comments?

     You may submit comments electronically, by mail, or through hand 
delivery/courier. To ensure proper

[[Page 42023]]

receipt by EPA, identify the appropriate docket ID number in the 
subject line on the first page of your comment. Please ensure that your 
comments are submitted within the specified comment period. Comments 
received after the close of the comment period will be marked ``late.'' 
EPA is not required to consider these late comments. If you wish to 
submit CBI or information that is otherwise protected by statute, 
please follow the instructions in Unit I.D. Do not use EPA dockets or 
e-mail to submit CBI or information protected by statute.
    1. Electronically. If you submit an electronic comment as 
prescribed in this unit, EPA recommends that you include your name, 
mailing address, and an e-mail address or other contact information in 
the body of your comment. Also, include this contact information on the 
outside of any disk or CD ROM you submit, and in any cover letter 
accompanying the disk or CD ROM. This ensures that you can be 
identified as the submitter of the comment and allows EPA to contact 
you in case EPA cannot read your comment due to technical difficulties 
or needs further information on the substance of your comment. EPA's 
policy is that EPA will not edit your comment, and any identifying or 
contact information provided in the body of a comment will be included 
as part of the comment that is placed in the official public docket, 
and made available in EPA's electronic public docket. If EPA cannot 
read your comment due to technical difficulties and cannot contact you 
for clarification, EPA may not be able to consider your comment.
    i. EPA Dockets. Your use of EPA's electronic public docket to 
submit comments to EPA electronically is EPA's preferred method for 
receiving comments. Go directly to EPA Dockets at http://www.epa.gov/
edocket, and follow the online instructions for submitting comments. 
Once in the system, select ``search,'' and then key in docket ID number 
OPP-2003-0205. The system is an ``anonymous access'' system, which 
means EPA will not know your identity, e-mail address, or other contact 
information unless you provide it in the body of your comment.
    ii. E-mail. Comments may be sent by e-mail to opp-docket@epa.gov, 
Attention: Docket ID number OPP-2003-0205. In contrast to EPA's 
electronic public docket, EPA's e-mail system is not an ``anonymous 
access'' system. If you send an e-mail comment directly to the docket 
without going through EPA's electronic public docket, EPA's e-mail 
system automatically captures your e-mail address. E-mail addresses 
that are automatically captured by EPA's e-mail system are included as 
part of the comment that is placed in the official public docket, and 
made available in EPA's electronic public docket.
    iii. Disk or CD ROM. You may submit comments on a disk or CD ROM 
that you mail to the mailing address identified in Unit I.C.2. These 
electronic submissions will be accepted in WordPerfect or ASCII file 
format. Avoid the use of special characters and any form of encryption.
    2. By mail. Send your comments to: Public Information and Records 
Integrity Branch (PIRIB) (7502C), Office of Pesticide Programs (OPP), 
Environmental Protection Agency, 1200 Pennsylvania Ave., NW., 
Washington, DC 20460-0001, Attention: Docket ID number OPP-2003-0205.
    3. By hand delivery or courier. Deliver your comments to: Public 
Information and Records Integrity Branch (PIRIB), Office of Pesticide 
Programs (OPP), Environmental Protection Agency, Rm. 119, Crystal Mall 
#2, 1921 Jefferson Davis Hwy., Arlington, VA, Attention: Docket 
ID number OPP-2003-0205. Such deliveries are only accepted during the 
docket's normal hours of operation as identified in Unit I.B.1.

D. How Should I Submit CBI to the Agency?

     Do not submit information that you consider to be CBI 
electronically through EPA's electronic public docket or by e-mail. You 
may claim information that you submit to EPA as CBI by marking any part 
or all of that information as CBI (if you submit CBI on disk or CD ROM, 
mark the outside of the disk or CD ROM as CBI and then identify 
electronically within the disk or CD ROM the specific information that 
is CBI). Information so marked will not be disclosed except in 
accordance with procedures set forth in 40 CFR part 2.
     In addition to one complete version of the comment that includes 
any information claimed as CBI, a copy of the comment that does not 
contain the information claimed as CBI must be submitted for inclusion 
in the public docket and EPA's electronic public docket. If you submit 
the copy that does not contain CBI on disk or CD ROM, mark the outside 
of the disk or CD ROM clearly that it does not contain CBI. Information 
not marked as CBI will be included in the public docket and EPA's 
electronic public docket without prior notice. If you have any 
questions about CBI or the procedures for claiming CBI, please consult 
the person listed under FOR FURTHER INFORMATION CONTACT.

E. What Should I Consider as I Prepare My Comments for EPA?

     You may find the following suggestions helpful for preparing your 
comments:
    1. Explain your views as clearly as possible.
    2. Describe any assumptions that you used.
    3. Provide copies of any technical information and/or data you used 
that support your views.
    4. If you estimate potential burden or costs, explain how you 
arrived at the estimate that you provide.
    5. Provide specific examples to illustrate your concerns.
    6. Make sure to submit your comments by the deadline in this 
notice.
    7. To ensure proper receipt by EPA, be sure to identify the docket 
ID number assigned to this action in the subject line on the first page 
of your response. You may also provide the name, date, and Federal 
Register citation.

II. What Action is the Agency Taking?

     EPA has received a pesticide petition as follows proposing the 
establishment and/or amendment of regulations for residues of a certain 
pesticide chemical in or on various food commodities under section 408 
of the Federal Food, Drug, and Cosmetic Act (FFDCA), 21 U.S.C. 346a. 
EPA has determined that this petition contains data or information 
regarding the elements set forth in FFDCA section 408(d)(2); however, 
EPA has not fully evaluated the sufficiency of the submitted data at 
this time or whether the data support granting of the petition. 
Additional data may be needed before EPA rules on the petition.

List of Subjects

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

    Dated: July 2, 2003.
Debra Edwards,
Director, Registration Division, Office of Pesticide Programs.

Summary of Petition

     The petitioner summary of the pesticide petition is printed below 
as required by FFDCA section 408(d)(3). The summary of the petition was 
prepared by BASF Corporation and represents the view of the petitioner. 
The petition summary announces the availability of a description of the 
analytical methods available to EPA for the detection and measurement 
of the

[[Page 42024]]

pesticide chemical residues or an explanation of why no such method is 
needed.

 BASF Corporation

 PP 3F6560

     EPA has received a pesticide petition (PP 3F6560) from BASF 
Corporation, 26 Davis Drive, Research Triangle Park, NC 27709-3528 
proposing, pursuant to section 408(d) of the Federal Food, Drug, and 
Cosmetic Act (FFDCA), 21 U.S.C. 346a(d), to amend 40 CFR part 180, by 
establishing a tolerance for residues of chlorfenapyr, [4-bromo-2-(4-
chlorophenyl)-1-(ethoxymethyl)-5-(trifluoromethyl)-1H-pyrrole-3-
carbonitrile]
on all food items in food handling establishments where 
food products are held, processed, and/or prepared at 0.01 parts per 
million (ppm). 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 support 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 (tomato, citrus, potato and head lettuce) is adequately 
understood and the residue of concern consists of the parent molecule. 
The metabolic pathway of chlorfenapyr in the laying hen and the 
lactating goat was also similar to that in laboratory rats.
    2. Analytical method. The GC analytical method, M 2398, which is 
proposed as the enforcement method for the residue of chlorfenapyr in 
or on food commodities, has a limit of quantitation (LOQ) of 0.01 ppm.
    3. Magnitude of residues. A study, based on protocol 
recommendations outlined in EPA's Residue Chemistry Test Guidelines, 
(OPPTS Harmonized Test Guideline 860.1460: Food Handling), was 
conducted with chlorfenapyr formulated as a 24% wettable powder.
     Applications were made to all potential sites within a commercial 
kitchen, including the perimeter of the restaurant kitchen, areas under 
cabinets and overhead cabinets, behind and on sides of cabinets and 
appliances, within the ceiling voids, and around pipes, cords, cables, 
counter legs, and wheels. The areas in which the product was applied 
are typical of those treated in a professional pest control operation 
in a commercial kitchen.
     The test was conducted using a wettable powder (WP) formulation at 
the maximum label rate for indoor use of 0.5% active ingredient (a.i.)/
1,000 ft2, which is also the approved maximum rate for 
indoor use in non-food/feed areas for the SC formulation (suspension in 
water), EPA Registration No. 241-392. The WP formulation has a larger 
particle size and will be more easily dispersed than the SC 
formulation, and therefore will best characterize the potential for 
exaggerated exposures to food items.
     Results from this study were that magnitudes of residues in all 
composite meal samples, both covered and uncovered, were below the LOQ 
of 10 parts per billion (ppb). Thus, there is a reasonable expectation 
that no finite residues of chlorfenapyr will result in food items 
following crack and crevice or spot applications of either the 25% 
wettable powder or the 21% suspension concentrate.

B. Toxicological Profile

     The toxicity of chlorfenapyr has been studied extensively and 
there is a complete data base to address the acute and chronic effects, 
effects on genetic material, the potential for carcinogenicity or 
teratogenicity, and effects on reproductive performance or growth of 
offspring. Toxicological data submitted previously that support this 
petition for tolerances of chlorfenapyr include:
    1. Acute toxicity. Based on EPA's toxicity category criteria, the 
acute toxicity category for chlorfenapyr technical, EPA Registration 
No. 241-366, is Category II or moderately toxic (signal word WARNING) 
and the acute toxicity category for the 2SC formulation, EPA 
Registration Nos. 241-374 and 241-392, 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, LD50 of 441/1,152 milligrams/kilogram body 
weight (mg/kg bwt) modifying factor (M/F) - Toxicology Category II.
    ii. Rabbit Dermal LD50: >2,000 mg/kg bwt M/F Toxicology 
Category III.
    iii. Acute Inhalation LC50: 0.83/ >2.7 milligrams per 
liter (mg/L) M/F Toxicology Category III.
    iv. Eye irritation: Moderately irritating - Toxicology Category 
III.
    v. Dermal irritation: Non-irritating - Toxicology Category IV.
    vi. Dermal sensitization: Non-sensitizer - Non sensitizer.
    vii. Acute neurotoxicity: NOEL 45 mg/kg bwt. Not an acute 
neurotoxicant
    2.  Genotoxicity. Chlorfenapyr technical (94.5%) was examined in a 
battery of in vitro and in vivo tests to assess its genotoxicity and 
its potential for carcinogenicity. These tests are summarized below.
    i. Microbial/Microsome Mutagenicity Assay: Non-mutagenic.
    ii. Mammalian Cell CHO/HGPRT Mutagenicity Assay: Non-mutagenic.
    iii. In vivo Micronucleus Assay: Non-genotoxic.
    iv. In vitro Chromosome Aberration Assay in CHO: Non-clastogenic.
    v. In vitro Abberation Assay in CHLC: Non-clastogenic.
    vi. Unscheduled DNA Synthesis (UDS) Assay: Non-genotoxic.
    3. Reproductive and developmental toxicity. Reproductive and 
developmental toxicity. Chlorfenapyr is neither a reproductive nor 
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:
    i. Rat oral teratology. No observed effect level (NOEL) for 
maternal toxicity 25 mg/kg bwt/day and NOEL for fetal/developmental 
toxicity at 225 mg/kg bwt/day.
    ii. Rabbit oral teratology. NOEL for maternal 5 mg/kg bwt/day and 
NOEL for fetal/developmental toxicity 30 mg/kg bwt/day.
    iii. Rat 2-generation reproduction. NOEL for parental toxicity/
growth and offspring development 60 parts per million (ppm) (5 mg/kg 
bwt/day) and NOEL for reproductive performance 600 ppm (44 mg/kg bwt/
day)
    4. Subchronic toxicity. The following are the results of the 
subchronic toxicity test that have been conducted with chlorfenapyr.
    i. 28-Day rabbit dermal - NOEL 100 mg/kg bwt/day.
    ii. 28-Day rat feeding - NOEL <600 ppm (<71.6 mg/kg bwt/day).
    iii. 28-Day mouse feeding - NOEL <160 ppm (<32 mg/kg bwt/day).
    iv. 13-Week rat dietary - NOEL 150 ppm (11.7 mg/kg bwt/day).
    v. 13-Week mouse dietary - NOEL 40 ppm (8.2 mg/kg bwt/day).
    vi. 13-Week dog dietary - NOEL 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:

[[Page 42025]]

    i. 1-Year neurotoxicity in rats. No observed adverse effect level 
(NOAEL) 60 ppm (2.6/3.4 mg/kg bwt/day M/F).
    ii. 1-Year dog dietary. NOAEL 120 ppm (4.0/4.5 mg/kg bwt/day M/F).
    iii. 24-Month rat dietary. NOAEL for chronic effects 60 ppm (2.9/
3.6 mg/kg bwt/day M/F and NOAEL for oncogenic effects 600 ppm (31/37 
mg/kg bwt/day M/F).
    iv. 18-Month mouse dietary - NOAEL 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 in plant and animal commodities.
    8. Endocrine disruption. 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 
effects.

C. Aggregate Exposure

    1. Dietary exposure. Based on the completeness and reliability of 
the toxicity data and the exposure assessment conducted, BASF concludes 
that there is a reasonable certainty that no harm will result from 
aggregate exposure to chlorfenapyr, including all dietary exposure.
    i. Food. There are currently no established U.S. permanent food 
tolerances for chlorfenapyr. There are two tolerance petitions pending 
at EPA; 0.5 ppm tolerance on imported citrus and 1.5 ppm tolerance on 
greenhouse grown vegetable, fruiting, crop group 8. A dietary exposure 
estimate based on theoretical maximum residue contribution (TMRC) was 
conducted using the Dietary Exposure Evaluation Model 
(DEEMTM) The TMRC is a ``worst case'' estimate for dietary 
exposure because it assumes that 100% of crop is treated and residues 
in the food are always found at the tolerance level. Additional 
assumptions used were all consumption of tomatoes-whole is from treated 
greenhouse grown tomatoes, greenhouse grown tomatoes are not processed, 
and all citrus juice in the U.S. is made from treated imported citrus 
pulp. Default processing factors were used to determine concentrations 
in processed fractions. The tolerance levels used in the dietary 
assessment were 0.5 ppm for citrus pulp, 1.5 ppm for vegetable, 
fruiting, group 8, and 0.01 ppm for all other crops.
    a. Acute exposure. The acute RfD used for this evaluation was 0.45 
mg/kg bwt calculated by applying the 100-fold safety factor to the NOEL 
from the acute neurotoxicity evaluation of chlorfenapyr. The acute 
exposure was evaluated at the 99.9th percentile. The most 
highly exposure sub-population was non-nursing infants (<1 yr old) 
which utilized 16.2% of the acute RfD. Therefore, based on the exposure 
assessment discussed above, BASF concludes there is a reasonable 
certainty that no harm will result from the acute dietary exposure to 
chlorfenapyr residues.
    b. Chronic exposure. The chronic RfD used for this evaluation was 
0.03 mg/kg bwt calculated by applying a 100-fold safety factor to the 
NOAEL from 1-year rat neurotoxicity study and the chronic feeding 
studies in the rat and mouse. The most highly exposure subpopulation 
was children 1-6 years of age which utilized 19.8% of the chronic RfD. 
Therefore, based on the exposure assessment discussed above, BASF 
concludes there is a reasonable certainty that no harm will result from 
the chronic dietary exposure to chlorfenapyr residues.
    ii. Drinking water. There is no concern for exposure to residues of 
chlorfenapyr in drinking water based on the approved, pending and 
proposed directions for use and its physical and chemical properties. 
Approved uses in the U.S. include applications to ornamental plants 
inside greenhouses, to a narrow band of soil adjacent to buildings and 
to crack-and-crevice and spot treatments inside structures. A pending 
use expands greenhouse applications to vegetable, fruiting, crop group 
8. The proposed use for food handling areas is also applied as a crack-
and-crevice and spot treatment inside structures. Chlorfenapyr has 
extremely low water solubility (120 ppb at 25 [deg]C)and is also 
immobile in soil and does not leach because it is strongly adsorbed to 
all common soil types.
    2. Non-dietary exposure. Non-dietary exposure to chlorfenapyr is 
expected to be negligible based on assessments made by EPA for the 
approved use on ornamentals grown in greenhouses, as a termiticide and 
for indoor applications for general pest control. These assessments 
were based on the physico-chemical characteristics of the compound, the 
intended use pattern, and available information concerning its 
environmental fate. The vapor pressure of chlorfenapyr is less than 1 x 
10-7 mm of mercury (Hg); therefore, the potential for non-
occupational exposure by inhalation is insignificant. These assessments 
also apply to the pending use on greenhouse grown vegetable, fruiting, 
crop group 8 and the proposed use in food handling areas.

D. Cumulative Effects

     The pyrrole insecticides represent a new class of chemistry with a 
unique mechanism of action. No other data are available that indicate 
that any toxicological effects produced by chlorfenapyr would be 
cumulative with those of any other compound.
     The parent molecule, chlorfenapyr is a pro-insecticide that 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 chlorfenapyr and 
CL 303,268 that are capable of reaching the mitochondria. This 
differential metabolism of chlorfenapyr to CL 303,268 in insects versus 
to other polar metabolites in mammals is responsible for the selective 
insect toxicity of the pyrroles.

[[Page 42026]]

E. Safety Determination

    1. U.S. population. Using the exposure assumptions described above, 
BASF has estimated that chronic dietary aggregate exposure to 
chlorfenapyr for the U.S. population was 0.002615 mg/kg bwt/day or 8.7% 
of the chronic RfD of 0.03 mg/kg bwt/day. Other than children less than 
12 years of age, hispanics are the U.S. population subgroup with the 
highest chronic exposure of 0.003403 mg/kg bwt/day, or 11.3% of the 
RfD. EPA has no concerns about exposure that are less than 100% of the 
RfD as the RfD represents the level at or below which daily aggregate 
dietary exposure over a lifetime will not pose appreciable risks to 
human health. It is therefore, safe to conclude that there is 
reasonable certainty that no harm to the overall U.S. population will 
result from chronic exposure to chlorfenapyr residues.
    2. Infants and children. Using the exposure assumption described 
above, BASF has estimated that the chronic dietary aggregate exposure 
to chlorfenapyr for children 1-6 years of age was 0.005936 mg/kg bwt/
day, or 19.8% of the chronic RfD of 0.03 mg/kg bwt/day. Children 1-6 
years of age were the sub-population that utilized the largest portion 
of the chronic RfD. It is therefore, safe to conclude that there is 
reasonable certainty that no harm to infants and children will result 
from chronic exposure to chlorfenapyr residues.

F. International Tolerances

     No Codex or Canadian tolerances/limits for residues in any food 
presently exist for chlorfenapyr. In Mexico there is a MRL of 0.3 ppm 
for cottonseed.
[FR Doc. 03-17900 Filed 7-15-03; 8:45 am]
BILLING CODE 6560-50-S