[Federal Register Volume 65, Number 169 (Wednesday, August 30, 2000)]
[Notices]
[Pages 52740-52746]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-22166]


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ENVIRONMENTAL PROTECTION AGENCY

[PF-960; FRL-6737-4]


Notice of Filing Pesticide Petitions to Establish Exemptions from 
the Requirement of Tolerances for Certain Pesticide Chemicals in or on 
Food

AGENCY: Environmental Protection Agency (EPA).

ACTION: Notice.

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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 docket control number PF-960, must be

[[Page 52741]]

received on or before September 27, 2000.

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-960 in the subject line on the first page of your 
response.

FOR FURTHER INFORMATION CONTACT: By mail: For MinerALL, contact Andrew 
C. Bryceland, Biopesticides and Pollution Prevention Division (7511C), 
Office of Pesticide Programs, Environmental Protection Agency, 1200 
Pennsylvania Ave., NW., Washington, DC 20460; telephone number: (703) 
305-6928; e-mail address: [email protected].
     For section II Platte Chemical Company, Inc., 2, 6-
diisopropylnapthalene (2, 6-DIPN), contact 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-960. 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., 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-960 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-960. 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.

[[Page 52742]]

    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 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 Cosmetic 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 support granting of these petitions. Additional 
data may be needed before EPA rules on the petitions.

List of Subjects

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


    Dated:August 21, 2000.

  Kathleen Knox, Acting

Director, Biopesticides and Pollution Prevention Division, Office of 
Pesticide Programs.

I. Ironwood Clay Company

 PP-0F6148

    EPA has received a pesticide petition (PP-0F6148) from Ironwood 
Clay Company, Inc., c/o Plant Sciences Inc., 342 Green Valley Road, 
Watsonville, CA 95076-1305, proposing, pursuant to section 408(d) of 
the FFDCA, 21 U.S.C. 346(d), to amend 40 CFR part 180 to establish an 
exemption from the requirement of a tolerance for the biochemical 
pesticide Oceanic Clay. Pursuant to section 408(d)(2)(A)(i) of the 
FFDCA, as amended, [Ironwood Clay Company] has submitted the following 
summary of information, data, and arguments in support of their 
pesticide petition. This summary was prepared by [Ironwood Clay 
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.

A. Product Name and Proposed Use Practices

    Oceanic Clay (tradename: MinerALL) is proposed for use as a crop 
protectant and growth stimulant on agricultural crops. For growing 
plants, MinerALL works as a crop protectant by forming a barrier on the 
plant surface. The barrier protects the plant from insects, heat, and 
stress, as well as creates an inhospitable environment for plant 
diseases such as powdery mildew, Botrytis, and Fusarium. The minerals, 
trace and rare earth elements in MinerALL provide nutrients to plants 
and beneficial microorganisms. Overall, Oceanic Clay can be classified 
as having a non-toxic mode of action.

B. Product Identity/Chemistry

    1. Identity of the pesticide and corresponding residues. Oceanic 
Clay is a naturally-occurring, pure clay complex composed of minerals, 
ions, and elements, including trace and rare earth elements.
    2. Magnitude of residue at the time of harvest and method used to 
determine the residue. Residues of Oceanic Clay are not expected at the 
time of harvest, and as such, an analytical method for residues is not 
applicable.
    3. A statement of why an analytical method for detecting and 
measuring the levels of the pesticide residue are not needed. An 
analytical method for residues is not applicable. Oceanic Clay is 
applied to growing crops that are washed as part of the postharvest and 
packaging process. As products containing Oceanic Clay leave a visible 
white film on treated surfaces, for cosmetic reasons treated produce 
would be washed before reaching the marketplace. Residues of Oceanic 
Clay are not expected on raw agricultural commodities (RAC) and there 
are no known toxicological effects related to dietary exposure to 
Oceanic Clay.

C. Mammalian Toxicological Profile

    Oceanic Clay has been evaluated for acute toxicity through the 
oral, inhalation, dermal, and ocular routes of exposure. The results of 
the studies have all indicated toxicity category IV, which poses no 
significant human health risks.
    The acute oral toxicity of Oceanic Clay in rats is greater than 
5,000 milligrams per kilograms (mg/kg) (toxicity category IV), and no 
toxicity or clinical abnormalities were observed throughout the study 
period. Acute inhalation in rats is greater than 2.47 mg/L (toxicity 
category IV), and no toxicity or clinical abnormalities were observed 
in test animals throughout the study. Eye irritation in rabbits was not 
observed at a dose of 0.1 mL (toxicity category IV), and no toxicity or 
clinical abnormalities were observed throughout the study period. Skin 
irritation in rabbits was not observed at a dose of 0.5 mL (toxicity 
category IV), and no toxicity or clinical abnormalities were observed 
throughout the study period. No dermal sensitization was observed in 
guinea pigs (toxicity category IV), and no toxicity or clinical 
abnormalities were observed throughout the study period. In addition, 
clinical studies have been conducted for evaluating safety of cosmetic 
use of the ingredient, primarily in facial products. In a dermal patch 
test of 35 participants, the ingredient was rated slightly irritating 
and non-allergenic. In a facial application test of 40 participants, no 
irritation was observed. No incidents of hypersensitivity have been 
reported by researchers, manufacturers or users.
    A waiver is being requested for acute dermal toxicity and 
genotoxicity data requirements, based on the fact that the active 
ingredient is known to be non-toxic and non-irritating to mammals. The 
ingredient is available commercially as a facial/cosmetic product for 
dermal application and it has been evaluated for dermal effects through 
various studies including clinical trials. Oceanic Clay is not related 
to any known mutagen and does not belong to a chemical class of 
compounds containing known mutagens. Finally, the ingredient has never 
been reported as causing any type of adverse effect to humans, in 
published literature or through commercial use.

D. Aggregate Exposure

    1. Dietary exposure--i. Food. Dietary exposure from use of Oceanic 
Clay, as proposed, would be expected to be minimal. Oceanic Clay is 
applied to growing crops that are washed as part of the postharvest and 
packaging process. As products containing Oceanic Clay leave a visible 
white film on treated surfaces, for cosmetic reasons treated produce 
would be washed before reaching the marketplace. Residues of Oceanic 
Clay are not expected on RAC and there are no known toxicological

[[Page 52743]]

effects related to dietary exposure to Oceanic Clay.
    ii.  Drinking water. Exposure to humans from residues of Oceanic 
Clay in consumed drinking water would be unlikely and there are no 
known toxicological effects related to exposure to Oceanic Clay.
    2. Non-dietary exposure. The potential for non-dietary exposure to 
the general population, including infants and children, is unlikely as 
the proposed use sites are commercial, agricultural and horticultural 
settings. However, non-dietary exposures would not be expected to pose 
any quantifiable risk due to a lack of residues of toxicological 
concern. Person protective equipment (PPE) mitigates the potential for 
exposure to applicators and handlers of the proposed products, when 
used in commercial, agricultural and horticultural settings.

E. Cumulative Exposure

    It is not expected that, when used as proposed, Oceanic Clay would 
result in residues that would remain in human food items. Oceanic Clay 
has a non-toxic mode of action and therefore has no common mechanism of 
toxicity with other substances.

F. Safety Determination

    1.  U.S. population. There have been no reports of toxins or 
secondary metabolites associated with Oceanic Clay, and acute toxicity 
studies have shown that Oceanic Clay is non-toxic, non-irritating and 
non-sensitizing when applied to test animals. Residues of Oceanic Clay 
are not expected on agricultural commodities, and there are no known 
toxicological effects related to exposure to Oceanic Clay.
    2. Infants and children. As mentioned above, residues of Oceanic 
Clay are not expected on agricultural commodities, and there are no 
known toxicological effects related to dietary exposure to Oceanic 
Clay. There is a reasonable certainty of no harm for infants and 
children from exposure to Oceanic Clay from the proposed uses.

G. Effects on the Immune and Endocrine Systems

    Oceanic Clay is a naturally-occurring clay. To date there is no 
evidence to suggest that Oceanic Clay functions in a manner similar to 
any known hormone, or that it acts as an endocrine disrupter.

H. Existing Tolerances

    There is no U.S. EPA Tolerance.

I. International Tolerances

    A Codex Alimentarium Commission maximum residue level (MRL) is not 
required for Oceanic Clay.

II. Platte Chemical Company, Inc.

PP-8G5008

    EPA has received a pesticide petition (PP-8G05008) from Platte 
Chemical Company, Inc., 419, 18th Street, P.O. Box 1286, 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 temporary exemption from 
the requirement of a tolerance for the biochemical pesticide 2, 6-
diisopropylnapthalene (2,6-DIPN).
    Pursuant to section 408(d)(2)(A)(i) of the FFDCA, as amended, 
Platte Chemical Company, Inc., has submitted the following summary of 
information, data, and arguments in support of their pesticide 
petition. This summary was prepared by Platte Chemical Company, Inc. 
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 (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. The temporary 
exemption from the requirement of a tolerance will expire on September 
22, 2000. This request for temporary exemption from the requirement of 
a tolerance is associated with an experimental use permit (EUP No. 
34704 EUP-13). 2,6-DIPN is a potato sprout inhibitor and the purpose of 
the experimental program is to test the efficacy of the active 
ingredient.

A. Product Name and Proposed Use Practices

    The end use product, Amplify sprout inhibitor, contains 
99.7% 2,6-DIPN. The experimental program will be conducted in potato 
storage facilities located in Idaho, Maine, Minnesota, North Dakota, 
Oregon, South Dakota, Washington, and Wisconsin. According to the 
National Agricultural Statistics Service, approximately 359 cut weight 
(cwt; 1 cwt equals approximately 100 pounds) of potatoes are grown per 
acre in the United States. The EUP program will utilize 2,500 pounds of 
active ingredient on approximately 150 million pounds of stored 
potatoes during 2000 and 2001. This represents approximately 4,180 
acres of potatoes. 2,6-DIPN is a plant growth regulator that is applied 
as an aerosol at the rate of one pound active ingredient per 600 cwt of 
potatoes, to achieve a rate of 16.6 parts per million (ppm). Only one 
application may be made while the potatoes are held in storage.

B. Product Identity/Chemistry

    1. Identity of the pesticide and corresponding residues. EPA has 
classified 2,6-DIPN as a biochemical pesticide (June 5, 1995, EPA 
letter from William Schneider to Fred Betz). The formulated end 
product, Amplify sprout inhibitor, contains 99.7% 2,6-DIPN as 
the active ingredient. In order to determine the magnitude of 2,6-DIPN 
residues, Platte conducted studies in/on potatoes and the effect of 
processing (i.e., washing and cooking) on 2,6-DIPN residues. According 
to the 2,6-DIPN label, one application of 16.6 ppm should be applied.
    2. Magnitude of residue--at the time of harvest and the method used 
to determine the residue. a. 2,6-DIPN magnitude of residues in/on 
potatoes postharvest storage. Platte conducted studies to determine 
2,6-DIPN residues in whole potatoes and peels at various times, up to 
180 days, following 1 to 3 treatments at the maximum application rate. 
A gas chromatography method was used to measure residues of 2,6-DIPN. 
Under the EUP, potatoes can only be treated once with 
Amplify. Treated potatoes must be held for a minimum of 30 
days before being released for processing. Potatoes were treated using 
a small chamber system that reproduced a commercial operation, but on a 
small scale. Use of the small chamber system produces realistic but 
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. Under these same 
conditions, residues in/on the peel were 1.01 ppm, 2.59 ppm, and 2.77 
ppm.
    b. 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. Potatoes were treated with a thermal fog of 2,6-DIPN,

[[Page 52744]]

in accordance with standard agronomic practices. Two application 
scenarios were studied: one 20 ppm active ingredient application and 3 
applications of 20 ppm active ingredient, totaling 60 ppm active 
ingredient. A liquid chromatography method was used to analyze residues 
of 2,6-DIPN in/on the potatoes.
    2,6-DIPN residues for 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 3 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 3 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 baked in aluminum foil, 2,6-DIPN residues were 
as follows: Potatoes treated once (20 ppm) had residues of 0.08 ppm, 
and 0.02 ppm. Potatoes treated 3 times (60 ppm) had residues of 0.50 
ppm, 0.07 ppm, and 0.24 ppm.
    For whole potatoes 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 3 times (60 ppm) had 
residues of 0.73 ppm, 0.02 ppm, and 0.46 ppm.
    For French fried potatoes, 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 3 times (60 ppm) had residues of 0.11 ppm, 
0.06 ppm, and 0.11 ppm.
    c. 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). A liquid chromatography 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.
    Residue levels in whole potatoes that have been treated with 2,6-
DIPN at the proposed application rate range from 0.22 ppm to 0.41 ppm 
at 30 DAT. The average residue value is 0.30 ppm. As stated earlier, 
the small chamber system used to treat potatoes in this study 
represents a worst-case scenario.
    3.  A statement of why an analytical method for detecting and 
measuring the levels of the pesticide residue are not needed. 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.

C. Mammalian Toxicological Profile

    1. Acute toxicity. Technical 2,6-DIPN exhibits low acute toxicity. 
It is a toxicity category III (based on eye irritation) biopesticide. 
The rat oral LD50 is greater than 5,000 mg/kg (toxicity 
category IV), the rabbit dermal LD50 is greater than 5,000 
mg/kg (toxicity category IV), and the rat inhalation LD50 is 
greater than 2.60 mg/L (toxicity category IV) at the maximum attainable 
condition. In addition, 2,6-DIPN is not a skin sensitizer in guinea 
pigs, shows no dermal irritation at 72 hours in rabbits (toxicity 
category IV), and shows minimal ocular irritation (toxicity category 
III) 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 hepatocyte cultures at 2 time 
points, and an in vivo mouse micronucleus assay have been conducted for 
2,6-DIPN. These studies show a lack of genotoxicity for 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, 37.5, 75, and 150 mg/kg/
day for 14 weeks. The no-observed adverse effect level (NOAEL) for this 
study is 1,500 ppm (75 mg/kg/day) in male and female rats was based on 
hepatocytic hypertrophy in the liver, tubular nephrosis in the kidney, 
and cortical cell atrophy in the adrenal gland at 3,000 ppm. A 
conservative NOAEL is 750 ppm (37.5 mg/kg/day) based on pupil 
constriction, minimal clinical pathology changes, and changes in organ 
weights (with no correlating histopathology findings) at 1,500 ppm.
    4. Developmental toxicity in rats. 2,6-DIPN was administered 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 (bwt) and feed consumption. The NOAEL for 
prenatal development toxicity was considered to be 150 mg/kg/day based 
on decreased fetal body weight. 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-
isopropylnapthalenes 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. Tissues 
were evaluated from animals sacrificed at 0, 2, 4, 24, and 48 hours 
following the single dose, and 2, 4, and 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 at 24 hours after the dose, and only slightly 
dropping at 48 hours.
    Significant distribution of DIPNs to liver, heart, kidney, and 
brain was 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 2-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.
    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 the pulmonary toxicity 
characteristic of napthalene.

[[Page 52745]]

    No data have been found in the literature that would indicate 2,6-
DIPN has any adverse effect on mammals. No incidents of 
hypersensitivity or any other adverse effects have been observed in 
individuals handling the material over the past 8 years.

D. Aggregate Exposure

    1. Dietary exposure--i. Food. Potential dietary exposure resulting 
from applications made under an experimental use permit (EUP) would be 
through the consumption of potato products and animal products from 
livestock-fed potato feed items. The registrant has made arrangements 
with processors of 2,6-DIPN-treated potatoes to prohibit feeding 
treated culls and potato waste to livestock. Thus, potential dietary 
exposure would result from consumption of treated potatoes only.
    2,6-DIPN is not approved for use on any food other than potatoes 
that are associated with Platte's EUP. Thus, there will be no exposure 
of 2,6-DIPN from food other than treated potatoes.
    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 database. 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.
    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 (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=0.54), boiled (PF=0.33), fried 
(PF=0.17), and peeled 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.
    The acute exposure estimate at the 99.9\th\ percentile of exposure 
for the overall U.S. population was 0.001770 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 margin of exposure (MOE) at 
the 99.9\th\ percentile of exposure is 28,246. For women of child-
bearing age, the acute exposure estimate at the 99.9\th\ percentile of 
exposure was 0.001070 mg/kg bwt/day (MOE=46,730). The population 
subgroup with the highest predicted level of acute exposure was 
children 1 to 6 years of age. Acute exposure for children 1 to 6 years 
of age was 0.003318 mg/kg bwt/day (MOE=15,070). 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 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=0.54), boiled 
(PF=0.33), fried (PF=0.17), and peeled potatoes (PF=0.15). Because of 
its status as a biopesticide, chronic toxicity studies would not 
normally be required for 2,6-DIPN; however, exposures were compared to 
a reference dose (RfD) of 0.0375 mg/kg bw/day based on a conservative 
NOAEL from a subchronic study and an uncertainty factor of 1,000. An 
additional 10-fold factor was incorporated because of the absence of a 
chronic toxicity study.
    For the overall U.S. population, chronic exposure was estimated to 
be 0.000095 mg/kg bwt/day or 0.3% of the RfD. Chronic exposure also was 
calculated for women of child-bearing age. The exposure estimate was 
0.000089 mg/kg bwt/day (0.2% of the RfD). For the most highly exposed 
population subgroup, children 1 to 6 years of age, chronic exposure was 
estimated to be 0.000175 mg/kg bwt/day or 0.5% 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 has any 
toxic effects on mammals that would be cumulative with those of any 
other chemicals. For the purposes of this exemption from tolerance, 
therefore, Platte assumes that 2,6-DIPN does not have a common 
mechanism of toxicity with other substances.

F. Safety Determination

    A dietary exposure assessment for 2,6-DIPN was conducted using 
Novigen Sciences' dietary exposure evaluation model (DEEM\tm\). 
Versions 6.73 (Acute Module) and 6.74 (Chronic Module). Dietary 
exposure to 2,6-DIPN was only based upon potatoes, including fresh 
potatoes. However, the Amplify label restricts application of 
the product to potatoes used only for processing. Therefore, the 
following is an extremely conservative assessment of the dietary 
exposure.
    1. U.S. population. The acute exposure estimate at the 99.9\th\ 
percentile of exposure for the overall U.S. population was 0.001770 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 
99.9\th\ percentile of exposure is 28,246. For women of child-bearing 
age, the acute exposure estimate at the 99.9\th\ percentile of exposure 
was 0.001070 mg/kg bwt/day (MOE = 46730). For the overall U.S. 
population, chronic exposure was estimated to be 0.000095 mg/kg bwt/day 
or 0.3% of the RfD. Chronic exposure also was calculated for women of 
child-bearing age. The exposure estimate was 0.000089 mg/kg bwt/day 
(0.2% of the RfD) for women of child-bearing age.
    2. Infants and children. Acute exposure for infants and children 1 
to 6 years of age were 0.002794 mg/kg bwt/day (MOE = 17,898) and 
0.003318 mg/kg bwt/day (MOE = 15,070), respectively. For the most 
highly exposed population subgroup, children 1 to 6 years of age, 
chronic exposure was estimated to be 0.000175 mg/kg bwt/day or 0.5% of 
the RfD. Chronic exposure also was calculated for infants. The exposure 
estimate was 0.000107 mg/kg bwt/day (0.3 percnt of the RfD) for 
infants.

[[Page 52746]]

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/International Tolerances

    No Codex maximum residue levels (MRLs) are established for residues 
of 2,6-DIPN in/on any food or feed crop.

[FR Doc. 00-22166 Filed 8-29-00; 8:45 am]
BILLING CODE 6560-50-S