[Federal Register Volume 68, Number 88 (Wednesday, May 7, 2003)]
[Notices]
[Pages 24458-24463]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 03-11200]


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ENVIRONMENTAL PROTECTION AGENCY

[OPP-2003-0139; FRL-7303-7]


Thiacloprid; 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-2003-0139, must be 
received on or before June 6, 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: Marilyn Mautz, Registration Division 
(7505C), Office of Pesticide Programs,

[[Page 24459]]

Environmental Protection Agency, 1200 Pennsylvania Ave., NW., 
Washington, DC 20460-0001; telephone number: (703) 305-6785; e-mail 
address: [email protected].

SUPPLEMENTARY INFORMATION:

I. General Information

A. Does this Action Apply to Me?

    You may be potentially affected by this action if you are an 
agricultural producer, food manufacturer, or pesticide manufacturer. 
Potentially affected entities may include, but are not limited to:
    [sbull] Crop production (NAICS 111)
    [sbull] Animal production (NAICS 112)
    [sbull] Food manufacturing (NAICS 311)
    [sbull] 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. Docket. EPA has established an official public docket for this 
action under docket identification (ID) number OPP-2003-0139. 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.1. 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 in 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 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-2003-0139. The system is an ``anonymous access'' system, which 
means EPA will not

[[Page 24460]]

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 [email protected], 
Attention: Docket ID Number OPP-2003-0139. 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-2003-0139.
    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-2003-0139. 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 (PP) 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: April 22, 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 the petitioner 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 pesticide chemical residues or an explanation of why no such 
method is needed.

Bayer CropScience and IR-4

PP 9F6060 and PP 3E6546

    EPA has received PP 9F6060 from Bayer CropScience 
(formerly, Bayer Corporation, 8400 Hawthorn Rd., P.O. Box 4913, Kansas 
City, MO 64120), P.O. Box 12014, 2 T.W. Alexander Dr., Research 
Triangle Park, NC 27709, and PP 3E6546 from Interregional 
Research Project Number 4 (IR-4), 681 U.S. Highway 1 South, 
North Brunswick, NJ 08902 proposing, pursuant to section 408(d) of 
FFDCA, 21 U.S.C. 346a(d), to amend 40 CFR part 180 by establishing a 
tolerance for residues of the insecticide thiacloprid ([3-[(6-chloro-3-
pyridinyl)methyl]-2-thiazolidinylidene]cyanamide (CAS No. 111988-49-9)) 
in or on the raw agricultural commodities:

    Bayer Petition (PP 9F6060) proposes to establish 
tolerances for:

    Apple, wet pomace at 0.6 parts per million (ppm).
    Cattle, meat at 0.2 ppm.
    Cattle, meat byproducts at 0.2 ppm.
    Cotton, gin byproducts at 11.0 ppm.
    Cotton, undelinted seed at 1.0 ppm.
    Fruit, pomace, group 11 at 0.3 ppm.
    Milk at 0.1 ppm.

    IR-4 Petition (PP 3E6546) proposes to establish tolerances 
for:

    Fruit, stone, group 12 at 0.5 ppm.

    EPA has determined that the petition contains data or information 
regarding the elements set forth in section 408(d)(2) of 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. In plants, the metabolism of thiacloprid is 
adequately understood for the purposes of

[[Page 24461]]

establishing these proposed tolerances. Unchanged parent thiacloprid 
accounted for 70% or greater of the residues in all plant metabolism 
studies (cotton, tomato, and apple), with the exception of the material 
identified in cotton seed. In cotton seed, the main component was the 
6-chloronicotinic acid metabolite, accounting for 45.8%. All residues 
contained the 6-chloro-pyridinyl moiety. In animals, parent thiacloprid 
was the major component in all edible tissues, milk, and eggs. All 
residues and metabolites in the animal tissues contained the 6-chloro-
pyridinyl moiety, same as in the plant tissues. Therefore, the residues 
of concern are the combined residues of thiacloprid and its metabolites 
containing the 6-chloro-pyridinyl moiety, all calculated as 
thiacloprid.
    2. Analytical method. The analytical method for determining 
residues in pome fruit and cotton samples is a common moiety method for 
thiacloprid and its metabolites containing the 6-chloro-pyridinyl 
moiety. This method utilizes oxidation, derivatization, and analysis by 
capillary gas chromatography with a mass-selective (MS) detector. There 
is a confirmatory method specific for thiacloprid and several 
metabolites utilizing high performance liquid chromatography (HPLC) 
with Electrospray MS/MS-detection. This HPLC/MS-MS method was used for 
analysis of the stone fruit samples. Thiacloprid and its metabolites 
are stable in cotton and pome fruit commodities for at least 24 months 
and in stone fruit commodities for at least 10 months when the 
commodities are frozen.
    3. Magnitude of residues--Cotton--Field trials were conducted with 
cotton in 12 different locations, representing 6 different EPA regions. 
Three foliar applications were made to mature cotton plants at a rate 
of 0.1 lb active ingredient/acre (a.i./A) with 3 to 11 days between 
applications. The pre-harvest interval (PHI) ranged from 12 to 20 days. 
The highest average field trial was 0.73 ppm in undelinted cotton seed. 
For gin trash, the HAFT residue was 10.10 ppm. The processing study, 
conducted with cottonseed, indicated no concentration in any cottonseed 
processed commodities.
    Pome fruit (apple/pear)--A total of 18 field trials (12 apple and 6 
pear) were conducted in 6 different EPA regions. Applications were made 
as ground-based foliar sprays at 0.25 lb ai/A with 6- to 8-day 
intervals. The highest residue at 30-day PHI was 0.277 ppm, in apples. 
The highest residue at a 45-day PHI was 0.258 ppm, occurring in pears. 
Although residues in pome fruit did not consistently decline in 
relation to sampling intervals, residues were generally lower at the 
longer PHI (45 days) in harvest experiments. In the apple processing 
study, residues concentrated in the wet pomace (1.8X) but did not 
concentrate in the apple juice. A home processing study indicated 
significant reduction in residues.
    Stone fruits (sweet cherry/peach/plum)--A total of 24 field trials 
(7 sweet cherry, 11 peach, and 6 plum) were conducted in different EPA 
regions (3 for sweet cherry, 7 for peach, and 3 for plum). Applications 
were made as ground-based foliar sprays at 0.25 lb ai/A with 6- to 8-
day intervals. The highest residue at the 14-day PHI was 0.423 ppm, in 
peaches. The highest residue at a 28-day PHI was 0.359 ppm, occurring 
in peaches. Residues in stone fruit raw agricultural commodities (RACs) 
consistently declined in relation to sampling intervals, with lower 
residues at the longer PHI (28 days).

B. Toxicological Profile

    1. Acute toxicity. The acute oral LD50 values for 
thiacloprid technical ranged from 444 (female) to 836 (male) milligram/
kilogram (mg/kg) in the rat. The acute dermal LD50 was 
greater than 2,000 mg/kg in rats. The 4-hour rat inhalation 
LD50 ranged from 1,223 (female) to >2,535 (male) mg/meter 
cubed (m\3\) air (aerosol). Thiacloprid was not irritating to rabbit 
skin or eyes. Thiacloprid did not cause skin sensitization in guinea 
pigs.
     2. Genotoxicty. Extensive mutagenicity studies conducted to 
investigate point and gene mutations, DNA damage and chromosomal 
aberration show thiacloprid to be non-genotoxic.
     3.Reproductive and developmental toxicity. In a 2-generation 
reproduction study, Sprague-Dawley rats were administered dietary 
levels of thiacloprid at levels of 0, 50, 300, and 600 ppm. The no-
observed-adverse-effect-levels (NOAELs) for reproductive parameters was 
established at 50 ppm, based on increased liver and thyroid weight 
gains in the parental and F1 generations. A developmental toxicity 
study was conducted with Wistar rats gavaged at 0, 2, 10, and 50 mg/kg. 
The following NOAELs were determined: Maternal toxicity, 10 mg/kg/day 
and developmental toxicity, 10 mg/kg/day. A developmental toxicity 
study was conducted with rabbits treated orally by gavage at 0, 2, 10, 
and 45 mg/kg. The following NOAELs were determined: Maternal toxicity, 
2 mg/kg/body weight (bwt)/day and developmental toxicity, 2 mg/kg/day. 
From the developmental toxicity studies in rats and rabbits, no primary 
developmental toxic potential could be derived. Additionally, a 
developmental neurotoxicity study was conducted at dietary doses of 0, 
50, 300, or 500 ppm in the female Sprague-Dawley rat. The targeted 
concentration of 50 ppm was considered a NOAEL for maternal toxicity 
and the F1 offspring. No specific neurobehavioral effects in the 
offspring were identified up to and including the highest dose tested 
of 500 ppm.
     4. Subchronic toxicity. 90-day feeding studies were conducted in 
rats, mice, and dogs. In the subchronic rat and dog studies, the 
demonstrated NOAELs were 25 ppm and 1,000 ppm, respectively. The 
subchronic mouse study did not demonstrate a NOAEL at the lowest level 
(50 ppm) tested.
    5.Chronic toxicity. A 2-year rat chronic toxicity/oncogenicity 
study demonstrated a NOAEL of 25 ppm. Liver enzyme induction occurred 
at doses of > 50 ppm. A 2-year mice oncogenicity demonstrated a NOAEL 
at the lowest dose of 30 ppm. A 1-year chronic toxicity study in dogs 
demonstrated a NOAEL of 250 ppm, with slight prostatic weight increases 
in some of the 1,000 ppm animals (possibly due to different maturation 
in the animals) being the only treatment-related findings. There is 
significant evidence that thiacloprid is not acting through a genetic 
mechanism (all genotoxicity studies are negative). Thiacloprid should 
be managed using a margin-of-exposure extrapolation. The dose response 
to thiacloprid shows the following pattern: First, at lower dose 
levels, thiacloprid induces liver enzymes. At moderate dose levels in 
animals, it increases liver enzymes and aromatase is induced. At the 
highest dose levels, repeated administration of thiacloprid induces 
liver enzymes, including aromatase, which leads to hormonal effects 
such as elevated estrogen levels, which indirectly cause uterine tumors 
in rats and ovarian luteomas in mice. High-dose thyroid tumors seen in 
the chronic rat study were determined to be related to thyroid hormone 
imbalance and not a direct effect of thiacloprid.
    6. Animal metabolism. In animals, parent thiacloprid was the major 
component in all edible tissues, milk, and eggs. All residues and 
metabolites in the animal tissues contained the 6-chloro-pyridinyl 
moiety, same as in the plant tissues. Therefore, the residues of 
concern are the combined residues of thiacloprid and its metabolites 
containing the 6-chloro-pyridinyl moiety, all calculated as 
thiacloprid.

[[Page 24462]]

    7. Metabolite toxicology. Two specific metabolites, KKO 2254 and 
WAK 6999, were examined toxicologically. In addition to negative Ames 
tests, the acute toxicological potential for both sexes, as measured by 
LD50, was determined to be >2,000 mg/kg for both 
metabolites. In light of these findings no special toxicological 
concerns, exceeding that of thiacloprid, would be expected from the 
metabolites of the parent compound
     8. Endocrine disruption. The toxicology database for thiacloprid 
is current and complete. Studies in this database include evaluation of 
the potential effects on reproduction and development and an evaluation 
of the pathology of the endocrine organs following short- or long-term 
exposure.

C. Aggregate Exposure

     1. Dietary exposure. Acute and chronic dietary analyses were 
conducted to estimate exposure to potential thiacloprid residues in/on 
the following crops: Fruit, pome, group; fruit, stone, group; and 
cotton using the DEEM\T\ software (Version 7.76) from Exponent, Inc. 
The 94-94,98 CSFII consumption database was used along with anticipated 
residues and processing factors where available. Projected percent crop 
treated values were incorporated into both the acute and chronic 
dietary exposure analyses at 20%, 10%, and 5% for pome fruit, stone 
fruit, and cotton, respectively. Exposure estimates to water were made 
based upon modeling. The acute reference dose (aRfD) (aRfD = 0.031 mg/
kg/bwt/day) was based upon an acute NOEL of 3.1 mg/kg/bwt/day from the 
acute oral neurotoxicity study in rats and an uncertainty factor of 
100. The chronic reference dose (cRfd) (cRfD = 0.012 mg/kg/bwt/day) was 
based upon a chronic NOEL of 1.2 mg/kg/bwt/day and an uncertainty 
factor of 100.
     i. Food. The acute dietary exposure estimates at the 99.9\th\ 
percentile for the U.S. population was calculated to be approximately 
7% of the aRfD. The population subgroup with the highest exposure was 
non-nursing infants (<1year old) at approximately 15% of the aRfD. 
Chronic dietary exposure estimates from residues of thiacloprid for the 
U.S. population was 0.2% of the cRfD. The population subgroup with the 
highest exposure was non-nursing infants with 1% of the cRfD utilized.
     ii. Drinking water. EPA's Standard Operating Procedure (SOP) for 
Drinking Water Exposure and Risk Assessments was used to perform the 
drinking water analysis for thiacloprid. This SOP utilizes a variety of 
tools to conduct drinking water assessment. These tools include water 
models such as SCI-GROW, FIRST, GENEEC, PRZM/EXAMS, and monitoring 
data. If monitoring data are not available then the models are used to 
predict potential residues in surface water and ground water. In the 
case of thiacloprid, monitoring data do not exist, therefore, FIRST and 
SCIGROW models were used to estimate a water residue. The calculated 
drinking water levels of comparison (DWLOC) for acute and chronic 
exposures for all adults and children greatly exceed the modeled 
thiacloprid drinking water estimated concentrations (DWEC). The acute 
DWLOC values are 1013 parts per billion (ppb) for adults (U. S. 
population) and 267 ppb for children. The worst case DWEC for acute 
scenarios is calculated to be 10.95 ppb using the FIRST surface water 
model. The chronic DWLOC values are 430 ppb for adults and 122 ppb for 
children. The DWEC for the worst case chronic scenario is 0.62 ppb 
(FIRST).
     2. Non-dietary exposure. There are no current plans to support 
thiacloprid uses on turf or ornamental plants, including homeowner 
uses.

D. Cumulative Effects

    Thiacloprid is thought to be part of a class of chemistry called 
the chloro-nicotinyls. For this class of chemistry and it's registered 
compounds EPA has not yet conducted a detailed review of common 
mechanisms to determine whether it is appropriate, or how to include 
these chemicals in a cumulative risk assessment. Unlike other 
pesticides for which EPA has followed a cumulative risk approach based 
on a common mechanism of toxicity, thiacloprid does not appear to 
produce a toxic metabolite produced by other substances. For the 
purposes of these tolerance actions; therefore, EPA has not assumed 
that thiacloprid has a common mechanism of toxicity with other 
substances.

E. Safety Determination

    1. U.S. population. Using the conservative exposure assumptions 
described in Unit C. of this petition and based on the completeness of 
the toxicity data, it can be concluded that acute dietary exposure to 
residues of thiacloprid from all proposed uses will utilize less than 
7% of the aRfD for the U.S. population and 15% of the aRfD for the most 
highly exposed subpopulation (non-nursing infants). EPA generally has 
no concerns for exposures below 100% of the reference dose (RfD), 
because the RfD represents the level at or below which exposure will 
not pose any appreciable risk to human health. Additionally, the acute 
DWLOC was calculated to be nearly 100 time greater than thiacloprid 
residues in water predicted by conservative models. The chronic dietary 
exposure occupies 0.2% of the cRfD for the U.S. population and 1% of 
the cRfD for the most highly exposed subpopulation (non-nursing 
infants). EPA generally has no concerns for exposures below 100% of the 
RfD, because the RfD represents the level at or below which daily 
aggregate exposure over a lifetime will not pose appreciable risks to 
human health. The chronic DWLOC was calculated to be nearly 700 and 200 
times greater than the thiacloprid residues in water predicted by 
conservative models. Therefore, there is a reasonable certainty that no 
harm will result to the general U.S. population from aggregate acute or 
chronic exposure to thiacloprid residues from proposed uses.
    2. Infants and children. In assessing the potential for additional 
sensitivity of infants and children to residues of thiacloprid, the 
data from developmental studies in both rat and rabbit and a 2-
generation reproduction study in rats have been considered. The 
developmental toxicity studies evaluate potential adverse effects on 
the developing animal resulting from pesticide exposure of the mother 
during prenatal development. The reproduction study evaluates effects 
from exposure to the pesticide on the reproductive capability of mating 
animals through 2 generations, as well as any observed systemic 
toxicity.
    FFDCA section 408 provides that EPA may apply an additional safety 
factor for infants and children in the case of threshold effects to 
account for pre- and post-natal effects and the completeness of the 
toxicity database. Based on current toxicological data requirements, 
the toxicology database for thiacloprid relative to pre- and post-natal 
effects is complete. Further for thiacloprid, the NOEL of 1.2 mg/kg/
bwt/day from the 2-year chronic toxicity/carcinogenicity study, which 
was used to calculate the cRfD (discussed in Unit C.1. of this 
petition), is already lower than the NOELs from the developmental 
studies in rats (10 mg/kg/bwt/day) and rabbits (2 mg/kg/bwt/day) and 
lower than the NOEL from the 2-year reproductive toxicity study in rats 
(50 mg/kg/bwt/day). Since a 100-fold uncertainty factor is already used 
to calculate the RfD, an additional safety factor for infants and 
children is not warranted.
    Using the conservative exposure assumptions described in Unit C. of 
this petition, Bayer CropScience has concluded that the total aggregate 
exposure to thiacloprid from all

[[Page 24463]]

proposed uses will utilize at most 15% of the aRfD and 1% of the cRfD 
even for the most highly exposed population subgroups (non-nursing 
infants). Therefore, there is a reasonable certainty that no harm will 
result to infants and children from the currently proposed uses of 
thiacloprid.

F. International Tolerances

    No CODEX Maximum Residue Levels (MRL's) have been established for 
residues of thiacloprid on any crops at this time.

[FR Doc. 03-11200 Filed 5-6-03; 8:45 am]
BILLING CODE 6560-50-S