[Federal Register Volume 66, Number 184 (Friday, September 21, 2001)]
[Notices]
[Pages 48677-48681]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-23482]


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ENVIRONMENTAL PROTECTION AGENCY

[PF-1043; FRL-6798-3]


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 control number PF-1043, must be 
received on or before October 22, 2001.

ADDRESSES: Comments may be submitted by mail, electronically, or in 
person. Please follow the detailed instructions for each method as 
provided in Unit I.C. of the SUPPLEMENTARY INFORMATION. To ensure 
proper receipt by EPA, it is imperative that you identify docket 
control number PF-1043 in the subject line on the first page of your 
response.

FOR FURTHER INFORMATION CONTACT: By mail: Driss Benmhend, Biopesticides 
and Pollution Prevention Division (7511C), Office of Pesticide 
Programs, Environmental Protection Agency, 1200 Pennsylvania Ave., NW., 
Washington, DC 20460; telephone number: (703) 308-9525; e-mail address: 
[email protected].

SUPPLEMENTARY INFORMATION:

I. General Information

A. Does this Action Apply to Me?

    You may be affected by this action if you are an agricultural 
producer, food manufacturer or pesticide manufacturer. Potentially 
affected categories and entities may include, but are not limited to:

------------------------------------------------------------------------
                                                          Examples of
           Categories                 NAICS codes         potentially
                                                       affected entities
------------------------------------------------------------------------
Industry                          111                 Crop production
                                  112                 Animal production
                                  311                 Food manufacturing
                                  32532               Pesticide
                                                       manufacturing
------------------------------------------------------------------------

    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 the table could also be 
affected. The North American Industrial Classification System (NAICS) 
codes have been provided to assist you and others in determining 
whether or not this action might apply to certain entities. If you have 
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 Additional Information, Including Copies of this 
Document and Other Related Documents?

    1. Electronically. You may obtain electronic copies of this 
document, and certain other related documents that might be available 
electronically, from the EPA Internet Home Page at http://www.epa.gov/. 
To access this document, on the Home Page select ``Laws and 
Regulations,'' ``Regulations and Proposed Rules,'' and then look up the 
entry for this document under the ``Federal Register--Environmental 
Documents.'' You can also go directly to the Federal Register listings 
at http://www.epa.gov/fedrgstr/.
    2. In person. The Agency has established an official record for 
this action under docket control number PF-1043. The official record 
consists of the documents specifically referenced in this action, any 
public comments received during an applicable comment period, and other 
information related to this action, including any information claimed 
as confidential business information (CBI). This official record 
includes the documents that are physically located in the docket, as 
well as the documents that are referenced in those documents. The 
public version of the official record does not include any information 
claimed as CBI. The public version of the official record, which 
includes printed, paper versions of any electronic comments submitted 
during an applicable comment period, is available for inspection in the 
Public Information and Records Integrity Branch (PIRIB), Rm. 119, 
Crystal Mall #2, 1921 Jefferson Davis Highway, Arlington, VA, from 8:30 
a.m. to 4 p.m.,

[[Page 48678]]

Monday through Friday, excluding legal holidays. The PIRIB telephone 
number is (703) 305-5805.

C. How and to Whom Do I Submit Comments?

    You may submit comments through the mail, in person, or 
electronically. To ensure proper receipt by EPA, it is imperative that 
you identify docket control number PF-1043 in the subject line on the 
first page of your response.
    1. By mail. Submit your comments to: Public Information and Records 
Integrity Branch (PIRIB), Information Resources and Services Division 
(7502C), Office of Pesticide Programs (OPP), Environmental Protection 
Agency, 1200 Pennsylvania Ave., NW., Washington, DC 20460.
    2. In person or by courier. Deliver your comments to: Public 
Information and Records Integrity Branch (PIRIB), Information Resources 
and Services Division (7502C), Office of Pesticide Programs (OPP), 
Environmental Protection Agency, Rm. 119, Crystal Mall #2, 1921 
Jefferson Davis Highway, Arlington, VA. The PIRIB is open from 8:30 
a.m. to 4 p.m., Monday through Friday, excluding legal holidays. The 
PIRIB telephone number is (703) 305-5805.
    3. Electronically. You may submit your comments electronically by 
e-mail to: [email protected], or you can submit a computer disk as 
described above. Do not submit any information electronically that you 
consider to be CBI. Avoid the use of special characters and any form of 
encryption. Electronic submissions will be accepted in Wordperfect 6.1/
8.0 or ASCII file format. All comments in electronic form must be 
identified by docket control number PF-1043. Electronic comments may 
also be filed online at many Federal Depository Libraries.

D. How Should I Handle CBI That I Want to Submit to the Agency?

    Do not submit any information electronically that you consider to 
be CBI. You may claim information that you submit to EPA in response to 
this document as CBI by marking any part or all of that information as 
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 version of the 
official record. Information not marked confidential will be included 
in the public version of the official record without prior notice. If 
you have any questions about CBI or the procedures for claiming CBI, 
please consult the person identified 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 
control 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 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: September 7, 2001.
Janet L. Andersen,
Director, Biopesticides and Pollution Prevention Division, Office of 
Pesticide Programs.

Summary of Petition

    The petitioner's summary of the pesticide petition is printed below 
as required by section 408(d)(3) of the FFDCA. 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.

Platte Chemical Company Petition Summary

PP 1F6338

    EPA has received a pesticide petition [PP 1F6338] from Platte 
Chemical Company, 419 18th Street, Greely, CO 80632, proposing pursuant 
to section 408(d) of the FFDCA, 21 U.S.C. 346a(d), to amend 40 CFR part 
180, to establish an exemption from the requirement of a tolerance for 
the biochemical pesticide 2,6-diisopropylnaphthalene (2,6-DIPN) in or 
on raw agricultural commodities.
    Pursuant to section 408(d)(2)(A)(i) of the FFDCA, as amended, 
Platte Chemical Company has submitted the following summary of 
information, data, and arguments in support of their pesticide 
petition. This summary was prepared by Platte Chemical Company and EPA 
has not fully evaluated the merits of the pesticide petition. The 
summary may have been edited by EPA if the terminology used was 
unclear, the summary contained extraneous material, or the summary 
unintentionally made the reader conclude that the findings reflected 
EPA's position and not the position of the petitioner.
    In the Federal Register of September 22, 1999 (64 FR 51245) (FRL-
6381-7), EPA issued a rule pursuant to section 408 of the Federal Food, 
Drug, and Cosmetic Act (FFDCA), 21 U.S.C. 346a, as amended by the Food 
Quality Protection Act (FQPA) (Public Law 104-170) establishing a 
temporary exemption from the requirement of a tolerance for residues of 
2,6-DIPN. This request for temporary exemption from the requirement of 
a tolerance was associated with an experimental use permit (EUP) (EUP 
No. 34704 EUP-13). At this time, Platte Chemical Company is seeking a 
full registration of 2,6-DIPN as a potato sprout inhibitor and is 
petitioning for a tolerance exemption.

A. Product Name and Proposed Use Practices

    2,6-Diisopropylnaphthalene (2,6-DIPN) will be applied at a rate of 
1 pound active ingredient per 600 cwt (1 cut weight equals 
approximately 100 pounds) of potatoes. All applications to

[[Page 48679]]

potatoes will be made indoors in potato storage facilities.

B. Product Identity/Chemistry

    1. Identity of the pesticide and corresponding residues. 2,6-
Diisopropylnaphthalene (2,6-DIPN), CAS Number 24157-81-1.
    2. Magnitude of residue at the time of harvest and method used to 
determine the residue--i. 2,6-DIPN magnitude of residues in/on 
potatoes, post harvest storage. Platte conducted studies to determine 
2,6-DIPN residues in whole potatoes and peels at various times, up to 
180 days, following one to three treatments at the maximum application 
rate. A liquid chromatograph (HPLC) method was used to measure residues 
of 2,6-DIPN. Potatoes were treated using a small chamber system that 
attempted to reproduce a commercial operation on a small-scale. Use of 
the small chamber system produces worst-case residue values compared to 
a full-scale commercial operation characterized by use conditions and 
practices that would tend to reduce residues to a greater extent than 
the chamber system. When treated once during storage at a rate of 1.2 
pounds active ingredient per 600 cwt. of potatoes, and sampled 30 days 
after treatment (DAT), residues for whole potatoes were 0.22 ppm, 0.28 
ppm, and 0.41 ppm (average 0.30 ppm). Under these same conditions, 
residues in/on the peel were 1.01 ppm, 2.59 ppm, and 2.77 ppm (average 
2.12 ppm).
    ii. 2,6-DIPN magnitude of residues in/on processing potatoes. A 
magnitude of the residue study was conducted to determine the effect of 
processing (i.e., baking, boiling, and frying) on whole red and russet 
potatoes. Use of the small chamber system produces worst-case residue 
values compared to a full-scale commercial operation characterized by 
use conditions and practices that would tend to reduce residues to a 
greater extent than the chamber system. Potatoes were treated with a 
thermal fog of 2,6-DIPN, in accordance with standard agronomic 
practices. Two application scenarios were studied: One 20 ppm active 
ingredient application and three applications of 20 ppm active 
ingredient (at 2-hour intervals), totaling 60 ppm active ingredient. A 
liquid chromatograph (HPLC) method was used to analyze residues of 2,6-
DIPN in/on the potatoes at 0 and 72 hours post-treatment.
    2,6-DIPN residues for washed whole potatoes were as follows: Whole 
potatoes treated once (20 ppm) at 0 DAT had residues of 0.17 ppm, 0.26 
ppm, 0.27 ppm, 0.15 ppm, 0.21 ppm, and 0.14 ppm. Potatoes treated once 
(20 ppm) at 3 DAT had residues of 0.14 ppm, 0.08 ppm, 0.18 ppm, 0.09 
ppm, 0.25 ppm, and 0.14 ppm. Potatoes treated three times (60 ppm) at 0 
DAT had residues of 0.97 ppm, 1.14 ppm, 0.59 ppm, 1.70 ppm, 2.10 ppm, 
and 1.44 ppm. Potatoes treated three times (60 ppm) at 3 DAT had 
residues of 0.58 ppm, 0.72 ppm, 0.75 ppm, 1.13 ppm, 0.57 ppm, and 0.48 
ppm.
    For whole potatoes (3 DAT) baked in aluminum foil, 2,6-DIPN 
residues were as follows: Potatoes treated once (20 ppm) had residues 
of 0.08 ppm, 0.08 ppm, and <0.02 ppm. Potatoes treated three times (60 
ppm) had residues of 0.50 ppm, 0.07 ppm, and 0.24 ppm.
    For whole potatoes (3 DAT) baked without aluminum foil, 2,6-DIPN 
residues were as follows: Potatoes treated once (20 ppm) had residues 
of 0.32 ppm, 0.26 ppm, and 0.13 ppm. Potatoes treated three times (60 
ppm) had residues of 0.73 ppm, <0.02 ppm, and 0.46 ppm.
    For potatoes (3 DAT) french fried, 2,6-DIPN residues were as 
follows: Potatoes treated once (20 ppm) had residues of 0.07 ppm, 0.04 
ppm, and 0.03 ppm. Potatoes treated three times (60 ppm) had residues 
of 0.11 ppm, 0.06 ppm, and 0.11 ppm.
    iii. 2,6-DIPN Determination of residues in/on whole potatoes and 
potato fractions (flesh and peel). A study was conducted to determine 
the residues in/on whole potatoes and the potato fractions (flesh and 
peel). Use of the small chamber system produces worst-case residue 
values compared to a full-scale commercial operation characterized by 
use conditions and practices that would tend to reduce residues to a 
greater extent than the chamber system. A liquid chromatograph (HPLC) 
method was used to analyze residues of 2,6-DIPN.
    2,6-DIPN residues for whole potatoes were as follows: Whole 
potatoes treated once (20 ppm) at 0 DAT had residues of 0.12 ppm, 0.16 
ppm, and 0.11 ppm. Potato peels treated once (20 ppm) at 0 DAT had 
residues of 1.76 ppm, 1.56 ppm, and 1.46 ppm. Potato flesh samples 
treated once (20 ppm) at 0 DAT had no detectable residues above the 
limit of quantification (LOQ) of 0.02 ppm. Peeled potato samples from 
0, 30, and 90 DAT were analyzed for residues; however, no residues 
above the LOQ of 0.02 ppm were detected.
    iv. Platte Chemical conducted research on 2,6-DIPN applied to 
potatoes in storage sheds under an Experimental Use Permit (EUP) during 
the 1999-2000 use season. This report is a brief summary of the residue 
data that were collected as part of this research.
    2,6-DIPN (Amplify Sprout Inhibitor; Amplify) 
was applied to potatoes in commercial sheds using commercial 
application equipment at 14 locations during the 1999-2000 use season. 
The application rates and the days post-treatment (number of days that 
the potatoes were held prior to release from the shed) varied. The 
application rates ranged from 11 ppm to 20 ppm, while the days post-
treatment ranged from 0 to 215 days. Of the 14 locations examined under 
the EUP, only one location studied potatoes released 30 days post-
treatment. The 30-day holding period is the requirement on the label 
for the section 3 registration of Amplify. However, 30 days 
is quite short for a holding period and would likely only be used if 
growing conditions were unusual, such as a particularly wet growing 
season. Hence, most locations studied under the EUP used longer holding 
periods.
    The potatoes at the one location that examined the 30-day holding 
period were treated at 11.0 ppm. These residue data have been adjusted 
so that they were on the basis as the application rate used in the 
magnitude of the residue study. The average residue in whole potatoes 
as tested under the EUP were 0.032 ppm (at 11 ppm) and 0.058 ppm 
(adjusted to 20 ppm).
    v. Summary. Residues on whole potatoes, especially peeled potatoes, 
are expected to be quite low. Further, residues are expected to decline 
from the time potatoes are removed from storage to the time of 
consumption. In addition, processing studies demonstrate that washing 
and cooking substantially reduce residues. Results from peeling studies 
show that quantifiable residues are not expected in the potato flesh. 
Because of the relatively low residues observed and the impact of 
processing, dietary exposure to 2,6-DIPN is expected to be minimal.
    3. Analytical method. An analytical method for residues is not 
applicable, as this petition proposes an exemption from the requirement 
of a tolerance for 2,6-DIPN based on the submitted residue data.

C. Mammalian Toxicological Profile

    1. Acute toxicity. Technical 2,6-DIPN exhibits low acute toxicity 
and is classified as toxicity category IV. The rat oral LD50 
is greater than 5,000 milligrams/kilograms (mg/kg) (toxicity category 
IV), the rabbit dermal LD50 is greater than 5,000 mg/kg 
(toxicity category IV), and the rat inhalation LC50 is 
greater than 2.60 mg/L (maximum attainable concentration) (toxicity 
category IV). In addition, 2,6-DIPN is not a skin sensitizer in guinea 
pigs, shows slight dermal irritation with reversal at 48 hours in 
rabbits (toxicity

[[Page 48680]]

category IV), and minimal ocular irritation (either redness, discharge 
or both) clearing by 48 hours (toxicity category IV) in rabbits. The 
end use formulation is the same as the technical formulation, it 
contains no intentionally added inert ingredients.
    2. Genotoxicity. Short-term assays for genotoxicity consisting of a 
bacterial reverse mutation assay (Ames test), an in vivo/in vitro 
unscheduled DNA synthesis in rat primary hepatocytes at two time 
points, and an in vivo mouse micronucleus assay were conducted with 
2,6-DIPN and were negative. A mouse lymphoma study conducted with 2,6-
DIPN was weakly positive in the absence of metabolic activation and 
equivocal in the presence of metabolic activation, in both cases at 
concentrations showing marked cytotoxicity. Based on a weight of 
evidence evaluation of mutagenicity data for 2,6-DIPN there is not any 
concern for genotoxicity of 2,6-DIPN.
    3. 90-Day subchronic toxicity study in rats. 2,6-DIPN was 
administered in the diet to rats (10 animals/sex/group) at doses of 0, 
750, 1,500, or 3,000 ppm (or approximately 0, 53.9, 104, and 208 mg/kg/
day for males and 0, 61.8, 121, and 245 mg/kg/day for females) for 13 
weeks. The no observed adverse effect level (NOAEL) for this study was 
1,500 ppm (104 and 121 mg/kg/day for males and females, respectively) 
in male and female rats and was based on decreased body weight gains 
and food consumption, and adrenal and kidney toxicity at the lowest 
observed adverse effect level (LOAEL) of 3,000 ppm (208 and 245 mg/kg/
day for males and females, respectively).
    4. Developmental toxicity in rats. 2,6-DIPN was administered by 
gavage to pregnant rats at doses of 0, 50, 150, and 500 mg/kg/day from 
days 6-19 of gestation. The maternal toxicity NOAEL was 50 mg/kg/day 
based on decreased body weight and feed consumption at the maternal 
LOAEL of 150 mg/kg/day. The NOAEL for prenatal developmental toxicity 
was 150 mg/kg/day based on decreased fetal body weight and a possible 
treatment-related cartilage anomaly at the developmental LOAEL of 500 
mg/kg/day. There is no evidence of teratogenicity or of increased fetal 
susceptibility to 2,6-DIPN.
    5. Metabolism. The metabolism of 2,6-DIPN and di-
isopropylnaphthalenes have been investigated, and several references to 
this work have been found in the published literature. In one study, 
rats were given a single dose or a daily oral dose for 1 month of 0.1 
g/kg bwt. Tissues were evaluated from animals sacrificed 0, 2, 4, 24, 
and 48 hours following the single dose, and 2, 4, 24 hours, and 7 and 
30 days following the repeated dose administration. DIPNs were found 
predominantly in body fat and subcutaneous fat 2 hours after the dose, 
with amounts increasing to 24 hours after the dose, and only slightly 
dropping at 48 hours. Significant distribution of DIPNs to liver, 
heart, kidney, and brain were seen at 2 hours; material in these 
compartments was eliminated by 48 hours following the single dose. 
Following repeated doses, the amount of DIPNs distributed in tissues 2 
hours after the last dose was lower than or equivalent to that seen 
following a single dose. The amount in body and subcutaneous fat 2 
hours following the last dose, although approximately two-fold higher 
than that seen following a single dose, diminished markedly by 30 days 
post-exposure. The half-life in fat was approximately 7 days. Thus, 
DIPNs showed a relatively low potential for persistent bioaccumulation.
    Another study investigated the urinary metabolites of 2,6-DIPN 
following a single oral dose. Approximately 23% of the dose was 
excreted in the urine by 24 hours post-dosing.
    6. Other tests. Naphthalene is associated with pulmonary necrosis 
(following intraperitoneal administration) and carcinogenesis in mice. 
A study has been reported in the public literature that compared the 
potential of napthalene, 2-methylnapthalene, 2-isopropylnaphthalene, 
and 2,6-DIPN to produce pulmonary damage in mice. The study's data 
suggest that 2,6-DIPN is very unlikely to share either the pulmonary 
toxicity or the carcinogenicity potential characteristic of napthalene.
    No data have been found in the literature that would indicate 2,6-
DIPN has any adverse effect on mammalian endocrine or immune systems. 
No incidents of hypersensitivity or any other adverse effects have been 
observed in individuals handling the material.

D. Aggregate Exposure

    1. Dietary exposure--i. Food--a. Acute dietary exposure. Exposure 
to chemicals that have the potential to elicit a toxic response after a 
relatively short period of exposure (acute toxicant) is calculated 
using a distribution of exposure estimated from the entire consumption 
data base. The exposure algorithm uses the basic relationship, that 
exposure is the product of the amount of food consumed and the 
magnitude of the residue in/on that food.
    Residues that are observed in/on crops are found to occur as a 
distribution. Likewise, food consumption patterns are best described by 
a consumption distribution. The most realistic calculation of acute 
dietary exposure, therefore, is to multiply the distribution of 
residues and the distribution of consumption using the Monte Carlo 
approach.
    For the acute analysis presented here, the Monte Carlo approach was 
used to estimate dietary exposure from potential residues of 2,6-DIPN 
in all potatoes. In the Monte Carlo model, the distribution of the 
residue data for whole raw unwashed potatoes (0.22 ppm to 0.41 ppm) was 
used in conjunction with individual consumption data for each food. The 
residue distribution was multiplied by the processing factors (PF) 
determined from 2,6-DIPN processing studies on baked (PF = 0.10), 
boiled (PF = 0.078), fried (PF = 0.032), and washed potatoes (PF = 
0.15). In addition, it was assumed that 100% of the potatoes consumed 
would be treated with 2,6-DIPN at the proposed label use rate. That is, 
no adjustments were made for the percentage of all potatoes that would 
be stored and treated with 2,6-DIPN, nor potatoes intended for fresh 
versus processing markets.
    The acute exposure estimate at the 99.9th percentile of exposure 
for the overall U.S. population is 0.000465 mg/kg bw/day. When compared 
to a maternal toxicity NOAEL of 50 mg/kg bw/day from a developmental 
toxicity study in rats, the Margin of Exposure (MOE) at the 99.9th 
percentile of exposure is 107437. For women of child-bearing age, the 
acute exposure estimate at the 99.9th percentile of exposure is 
0.000142 mg/kg bw/day (MOE = 351939). The population subgroup with the 
highest predicted level of acute exposure was children 1 to 6 years of 
age. Acute exposures for children 1 to 6 years of age were 0.000682 mg/
kg bw/day (MOE = 73309). Because the predicted exposures, expressed as 
MOEs, are well above 100, there is reasonable certainty that no acute 
effects would result from dietary exposure to 2,6-DIPN.
    b. Chronic dietary exposure. Chronic exposure estimates were 
calculated for potential residues of 2,6-DIPN in/on all potatoes, 
including those destined for processing (e.g., frozen, canned). 
Generally, exposure to chemicals that have the potential to elicit a 
toxic response after an extended period of exposure (chronic toxicant) 
is calculated using per-capita mean consumption estimates and an 
average residue value. As a conservative estimate of potential long-
term dietary exposure, it was

[[Page 48681]]

assumed that 100% of the potatoes consumed would contain 2,6-DIPN 
residues at 0.30 ppm (average residue). This residue value was 
multiplied by the processing factors (PF) determined from 2,6-DIPN 
processing studies on baked (PF = 0.10), boiled (PF = 0.078), fried (PF 
= 0.032), and washed potatoes (PF = 0.15).
    A risk assessment was performed for 2,6-DIPN using the subchronic 
toxicity study in rats NOAEL of 104 or 121 mg/kg/day (males and 
females, respectively). Although the developmental toxicity study 
indicates a lower NOAEL for the same toxicity (reduced body weight, 
weight gain, and food consumption), the maternal LOAEL of 150 mg/kg/day 
is between the subchronic NOAEL of 104-121 mg/kg/day and the LOAEL of 
208-245 mg/kg/day. However, the maternal toxicity NOAEL of 50 mg/kg/day 
is appropriate for use in characterization of risks for the 
subpopulation of women of childbearing age.
    Because of its status as a biopesticide, chronic toxicity studies 
would not normally be required for 2,6-DIPN; however, a reference dose 
(RfD) of 1 mg/kg/day can be established for purposes of chronic dietary 
risk assessment if necessary. The RfD value is based on the NOAEL from 
the subchronic rat study and use of a 100-fold uncertainty factor (10X 
for interspecies extrapolation and 10X for intraspecies variability, 
RfD = 104/100 = 1 mg/kg/day). Retention of an FQPA safety factor is not 
necessary for 2,6-DIPN. Developmental data in rats showed no unique 
susceptibility to DIPN.
    For the overall U.S. population, chronic exposure was estimated to 
be 0.000033 mg/kg bwt/day or <0.1 % of the RfD. Chronic exposure also 
was calculated for women of child-bearing age. Exposure estimates were 
0.000019 mg/kg bwt/dw (<0.1 % of the RfD). For the most highly exposed 
population subgroup, children 1 to 6 years of age, chronic exposure was 
estimated to be 0.000119 mg/kg bw/day or <0.1 % of the RfD.
    ii. Drinking water. There is no established maximum concentration 
level for 2,6-DIPN in water. Based on the low use rate and an indoor 
use pattern that is not widespread, residues of 2,6-DIPN in drinking 
water and exposure from this route is unlikely.
    2. Non-dietary exposure. 2,6-DIPN is not registered for any use 
that could result in non-occupational, non-dietary exposure to the 
general population.

E. Cumulative Exposure

    There is no evidence to indicate or suggest that 2,6-DIPN shares 
any mechanism of toxicity in common with those of any other pesticides. 
Therefore, cumulative exposure concerns are not anticipated.

F. Safety Determination

    1. U.S. population. The acute exposure estimate at the 99.9th 
percentile of exposure for the overall U.S. population was 0.000465 mg/
kg bwt/day. When compared to a maternal toxicity NOAEL of 50 mg/kg bwt/
day from a developmental toxicity study in rats, the MOE at the 99.9th 
percentile of exposure is 107437. For women of child-bearing age, the 
acute exposure estimate at the 99.9th percentile of exposure was 
0.000142 mg/kg bwt/day (MOE = 351939). For the overall U.S. population, 
chronic exposure was estimated to be 0.000033 mg/kg bwt/day or <0.1% of 
the RfD. Chronic exposure also was calculated for women of child-
bearing age. Exposure estimates were 0.000019 mg/kg bwt/day (<0.1% of 
the RfD) for women of child-bearing age.
    2. Infants and children. Acute exposures for infants and children 1 
to 6 years of age were 0.000682 mg/kg bwt/day (MOE = 73309). For the 
most highly exposed population subgroup, children 1 to 6 years of age, 
chronic exposure was estimated to be 0.000119 mg/kg bwt/day or <0.1% of 
the RfD.

G. Effects on the Immune and Endocrine Systems

    Platte has no information to suggest that 2,6-DIPN will adversely 
affect the immune or endocrine systems. The Agency is not requiring 
information on endocrine effects of this biochemical pesticide at this 
time.

H. Existing Tolerances

    No codex maximum residue levels are established for residues of 
2,6-DIPN in/on any food or feed crop.
[FR Doc. 01-23482 File 9-20-01; 8:45 am]
BILLING CODE 6560-50-S