Document ID: EPA-HQ-OPP-2006-0373-0001
Agency: epa
Document Type: Rule
Title: 2, 6-Diisopropylnaphthalene; Time-Limited Pesticide Tolerances
Posted Date: 2006-09-01T12:56:47Z

[Federal Register: September 1, 2006 (Volume 71, Number 170)]
[Rules and Regulations]               
[Page 52003-52012]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr01se06-11]                         

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 180

[EPA-HQ-OPP-2006-0373; FRL-8081-9]

 
2, 6-Diisopropylnaphthalene; Time-Limited Pesticide Tolerances

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: This regulation establishes time-limited tolerances for 
residues of 2, 6-Diisopropylnaphthalene, resulting from post-harvest 
applications to potato, in or on fat (cattle, goat, hog, horse, and 
sheep) at 0.8 part per million (ppm); liver (cattle, goat, hog, horse, 
and sheep) at 0.3 ppm; meat (cattle, goat, hog, horse, and sheep) at 
0.1 ppm; meat byproducts (cattle, goat, hog, horse, and sheep) at 0.1 
ppm; milk at 0.1 ppm; potato at 2.0 ppm; and potato, wet peel at 6.0 
ppm. Loveland Products, Inc. had requested permanent tolerances (in or 
on whole potato and potato peels at 2 and 6 ppm, respectively) under 
the Federal Food, Drug, and Cosmetic Act (FFDCA), as amended by the 
Food Quality Protection Act of 1996 (FQPA). The time-limited tolerances 
will expire on August 1, 2009.

DATES: This regulation is effective September 1, 2006. Objections and 
requests for hearings must be received on or before October 31, 2006, 
and must be filed in accordance with the instructions provided in 40 
CFR part 178 (see also Unit I.C. of the SUPPLEMENTARY INFORMATION).

ADDRESSES: EPA has established a docket for this action under docket 
identification (ID) number EPA-HQ-OPP-2006-0373. All documents in the 
docket are listed in the index for the docket. Although listed in the 
index, some information is not publicly available, e.g., Confidential 
Business Information (CBI) or other information whose disclosure is 
restricted by statute. Certain other material, such as copyrighted 
material, is not placed on the Internet and will be publicly available 
only in hard copy form. Publicly available docket materials are 
available in the electronic docket at http://www.regulations.gov, or, 

if only available in hard copy, at the OPP Regulatory Public Docket in 
Rm. S-4400, One Potomac Yard (South Building), 2777 S. Crystal Drive, 
Arlington, VA. The 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.

FOR FURTHER INFORMATION CONTACT: Denise Greenway, Biopesticides and 
Pollution Prevention Division (7511P), Office of Pesticide Programs, 
Environmental Protection Agency, 1200 Pennsylvania Ave., NW., 
Washington, DC 20460-0001; telephone number: (703) 308-8263; e-mail 
address:greenway.denise@epa.gov.

SUPPLEMENTARY INFORMATION:

I. General Information

A. Does this Action Apply to Me?

    You may be potentially affected by this action if you are an 
agricultural producer, food manufacturer, or pesticide manufacturer. 
Potentially affected entities may include, but are not limited to:
     Crop production (NAICS code 111).
     Animal production (NAICS code 112).
     Food manufacturing (NAICS code 311).
     Pesticide manufacturing (NAICS code 32532).
    This listing is not intended to be exhaustive, but rather provides 
a guide for readers regarding entities likely to be

[[Page 52004]]

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 Access Electronic Copies of this Document?

    In addition to accessing an electronic copy of this Federal 
Register document through the electronic docket at http://www.regulations.gov
, you may access this ``Federal Register'' document 

electronically through the EPA Internet under the ``Federal Register'' 
listings at http://www.epa.gov/fedrgstr. You may also access a 

frequently updated electronic version of 40 CFR part 180 through the 
Government Printing Office's pilot e-CFR site at http://www.gpoaccess.gov/ecfr.
 To access the OPPTS Harmonized Guidelines 

referenced in this document, go directly to the guidelines at http://www.epa.gov/opptsfrs/home/guidelin.htm/
.

C. Can I File an Objection or Hearing Request?

    Under section 408(g) of the FFDCA, as amended by the FQPA, any 
person may file an objection to any aspect of this regulation and may 
also request a hearing on those objections. The EPA procedural 
regulations which govern the submission of objections and requests for 
hearings appear in 40 CFR part 178. You must file your objection or 
request a hearing on this regulation in accordance with the 
instructions provided in 40 CFR part 178. To ensure proper receipt by 
EPA, you must identify docket ID number EPA-HQ-OPP-2006-0373 in the 
subject line on the first page of your submission. All requests must be 
in writing, and must be mailed or delivered to the Hearing Clerk on or 
before October 31, 2006.
    In addition to filing an objection or hearing request with the 
Hearing Clerk as described in 40 CFR part 178, please submit a copy of 
the filing that does not contain any CBI for inclusion in the public 
docket that is described in ADDRESSES. Information not marked 
confidential pursuant to 40 CFR part 2 may be disclosed publicly by EPA 
without prior notice. Submit your copies, identified by docket ID 
number EPA-HQ-OPP-2006-0373, by one of the following methods.
     Federal eRulemaking Portal. http://www.regulations.gov. 

Follow the on-line instructions for submitting comments.
     Mail. Office of Pesticide Programs (OPP) Regulatory Public 
Docket (7502P), Environmental Protection Agency, 1200 Pennsylvania 
Ave., NW., Washington, DC 20460-0001.
     Delivery. OPP Regulatory Public Docket (7502P), 
Environmental Protection Agency, Rm. S-4400, One Potomac Yard (South 
Building), 2777 S. Crystal Drive, Arlington, VA. Deliveries are only 
accepted during the Docket's normal hours of operation (8:30 a.m. to 4 
p.m., Monday through Friday, excluding legal holidays). Special 
arrangements should be made for deliveries of boxed information. The 
Docket telephone number is (703) 305-5805.

II. Background and Statutory Findings

    In the Federal Register of December 9, 2005 (70 FR 73234) (FRL-
7748-5), EPA issued a notice pursuant to section 408(d)(3) of the 
FFDCA, 21 U.S.C. 346a(d)(3), announcing the filing of a pesticide 
petition (PP 1F6338), originated by Platte Chemical Company, now 
Loveland Products, Inc., 7251 W. 4th Street, Greely, CO 
80634. The petition requested that 40 CFR 180.590 be amended by 
establishing permanent tolerances for residues of the biochemical 
pesticide 2, 6-diisopropylnaphthalene (2, 6-DIPN), resulting from post-
harvest applications to potato, in or on whole potato and potato peels 
at 2 and 6 parts per million (ppm), respectively. The electronic docket 
(EPA-HQ-OPP-2005-0318) for this notice included a summary of the 
petition prepared by Loveland Products, Inc., the registrant. In 
submitting this petition, Loveland Products, Inc. (formerly Platte 
Chemical Company) is relying on new data summarized in the cited 
summary, and also on information previously submitted by Platte 
Chemical Company, which was summarized in a previous notice of filing 
published in the Federal Register on September 21, 2001 (66 FR 48677) 
(FRL-6798-3). New data submitted to the Agency by Loveland Products, 
Inc. on February 8, 2005 and summarized by the company in the current 
petition are a magnitude of the residue in livestock study, which was a 
condition of registration for the subject active ingredient when the 
end-use product, EPA Registration Number 34704-843, was registered on 
July 31, 2003. Other new data summarized in the electronic docket for 
the December 9, 2005 notice were analytical enforcement methods to 
determine residues in potato, potato peels (submitted by Loveland 
Products, Inc. on February 15, 2005), and livestock commodities 
(submitted by Loveland Products, Inc. on February 8, 2005); and a 
magnitude of the residue study which presented recalculations of 
previously submitted data to support proposed label amendments 
(submitted by Loveland Products, Inc. on July 20, 2005). As explained 
in this final rule, the Agency is not granting the two permanent 
tolerances sought in Loveland Products, Inc.'s current petition, but 
rather is establishing several time-limited tolerances that will expire 
on August 1, 2009.
    One comment was received from a private citizen opposing the 
establishment of the permanent numeric tolerances sought by the 
petitioner.
    1. Comment. One commenter objected to the use of 2, 6-DIPN on 
potato in storage, citing information from 60 references on 
naphthalene, which is a structurally related chemical. There were 24 
citations containing information on human health hazards and 36 
describing animal studies. The hazards of concern associated with 
naphthalene exposure included hemolytic anemia, cataracts, and 
respiratory tract toxicity. Reported no-observed-adverse-effect levels 
(NOAEL) for naphthalene ranged from 50 milligrams/kilogram/day (mg/kg/
day) (an oral chronic toxicity study in the rat) to 200 mg/kg/day 
(administered by gavage 5 days/week for 13 weeks in mice).
    EPA response. Toxicity data on 2, 6-DIPN indicate a NOAEL of 
approximately 100 mg/kg/day based on decreased body weights in a 13-
week feeding study in rats with supporting evidence from a 
developmental toxicity study in rats. This NOAEL is in the range of 
NOAELs described by the commenter for general toxicity of naphthalene 
(i.e., decreased body weight). However, one of the commenter's 
references in particular indicated that 2, 6-DIPN may be less toxic 
than naphthalene since the plant regulator was the least toxic of the 
four compounds tested for respiratory tract toxicity by the 
investigators (the other three were naphthalene, 2-methylnaphthalene, 
and 2-isopropylnaphthalene; Honda, T., et al. Chem Pharm Bull 38 
(11):3130-5 (1990)). This study suggests that alkyl substituted 
naphthalenes such as 2, 6-DIPN are not as likely to form toxic epoxides 
in epoxidase-rich lung tissues.
    The 12 citations describing studies of respiratory tract toxicity 
indicated that most investigators chose injection (an unlikely route of 
exposure for pesticides), or dose levels much higher than those used to 
define dose-response

[[Page 52005]]

relationships (including NOAELS) for general toxicity, or both, to 
characterize toxicity in the lung. Therefore, use of the NOAELs based 
on decreased body weight are assumed to be an adequate basis for 
determining a reference dose for 2, 6-DIPN's risk assessment since body 
weight decreases occurred at lower doses than those causing respiratory 
toxicity.
    The Agency's Integrated Risk Information System (IRIS) contains a 
report entitled ``Toxicological Review of Naphthalene'' dated August, 
1998 (available at http://www.epa.gov/iris/toxreviews/ as of May 4, 

2006), which includes the citations found in the comment in a 
comprehensive review and assessment of the literature on naphthalene. 
That report notes (at page 41), ``the limited subchronic oral animal 
data identify decreased body weight in rats as the most appropriate 
critical effect for deriving a chronic oral RfD (reference dose) for 
naphthalene.''
    The IRIS report further indicates (page 41) that an RfD of 0.02 mg/
kg/day ``...was derived by dividing a duration-adjusted NOAEL, 71 mg/
kg/day, for mean terminal body weight decrease (> 10% of control) in 
male rats... by an uncertainty factor of 3,000 (10 to extrapolate from 
rats to humans; 10 to protect sensitive humans; 10 to extrapolate from 
subchronic to chronic exposure; and 3 for database deficiencies,...).'' 
A similar derivation of RfDs for 2, 6-DIPN (described as acute or 
chronic population adjusted doses; aPAD and cPAD, respectively) is 
accomplished by dividing the 100 mg/kg/day NOAEL by a thousandfold 
uncertainty factor (10 for intraspecies variability, 10 for 
interspecies extrapolation, and an additional 10 to consider 
sensitivity of infants and children as required by the Food Quality 
Protection Act (FQPA)). Application of an additional threefold 
uncertainty factor based on data deficiencies was not done for 2, 6-
DIPN, because the plant regulator is classified as ``biochemical-like'' 
based on its structural similarity to 1-isopropyl-4,6-
dimethylnaphthalene, 1-methyl-7-isopropylnaphthalene, and 4-isopropyl-
1,6-dimethylnaphthalene which are naturally occurring plant regulators. 
Based on the functional and structural similarities between these 
naturally occurring alkyl substituted naphthalene plant regulators, 
their plant-specific modes of action, and the decreased toxicity 
associated with these compounds, 2, 6-DIPN's classification as 
``biochemical-like'' requires less data for registration (i.e., the 
data set required by 40 CFR 158.690 to support registration of 
biochemical or biochemical-like pesticides is reduced compared to that 
required for conventional chemical pesticides). In addition, using the 
3,000-fold uncertainty factor for the reasons described in the IRIS 
assessment would triple the dietary risks described below, but those 
risks still do not exceed the level of concern for 2, 6-DIPN (i.e., 
dietary exposure remains < 100% of the acute population adjusted dose/
chronic population adjusted dose (aPAD/cPAD)).
    A late, ten-point comment was received from 1,4Group, Inc. Each of 
the ten points raised by this comment is summarized individually below, 
followed by EPA's response.
    2. Comment 1. It is requested that the Agency address whether the 
three (unregistered) chemicals (1-isopropyl-4, 6-dimethylnaphthalene; 
1-methyl-7-isopropylnaphthalene; 4-isopropyl-1, 6-dimethylnaphthalene) 
to which 2, 6-DIPN is functionally/structurally similar, share a common 
mechanism of toxicity.
    EPA Response. A ``common mechanism of toxicity'' in the context of 
cumulative effects relates to the safety evaluation undertaken by EPA 
in connection with related pesticides (e.g., organophosphates with the 
common mechanism of toxicity such as cholinesterase inhibition). In 
this case, 2, 6-DIPN and the three functionally and structurally 
similar substances all act as plant regulators by a ``mode of action'' 
that is specific to plants, and therefore, their common mode of action 
is unlikely to be relevant to a mechanism of toxicity in animals or 
humans. The comparison of the four chemicals is made to demonstrate 
biological activity (plant regulation in this case), which the Agency 
has characterized as a non-toxic mode of action with respect to 
pesticidal activity.
    3. Comment 2. This comment identifies a statement from the Agency's 
2, 6-Diisopropylnaphthalene Biopesticide Registration Action Document 
(BRAD), where on page one 2, 6-DIPN was incorrectly said to be 
``...functionally and structurally identical to the naturally occurring 
plant regulator in potato.''
    EPA response. The Agency recognizes the error; potato naturally 
contain more than one plant regulator, and the synthetic 2, 6-DIPN is 
similar in function and structure to 1-isopropyl-4, 6-
dimethylnaphthalene; 1-methyl-7-isopropylnaphthalene; and 4-isopropyl-
1, 6-dimethylnaphthalene, which are naturally-occurring compounds in 
plant tissues, including those of potato.
    4. Comment 3. This comment is a request that the Agency provide 
documentation of the natural occurrence of the three substances (1-
isopropyl-4, 6-dimethylnaphthalene; 1-methyl-7-isopropylnaphthalene; 
and 4-isopropyl-1, 6-dimethylnaphthalene) to which 2, 6-DIPN is 
similar.
    EPA response. 2, 6-Diisopropylnaphthalene is functionally and 
structurally similar to the three referenced compounds, which are 
naturally-occurring in plants. 1-isopropyl-4, 6-dimethylnaphthalene 
(CAS No. 4545-23-7) is also known as daucalene or isocadalene and is 
found in roots and plant oils:
     Bicchi et al., 1983. Journal of High Resolution 
Chromatography and Chromatographic Communications 6(4): 213-215.
     Van Dooren et al., 1981. Planta Medica 42(4): 385-389).
    1-methyl-7-isopropylnaphthalene (CAS No. 490-65-3) is also known as 
eudalene and is present in plant oils:
     Abegaz and Yohannes, 1982. Phytochemistry 21(7): 1791-
1793).
    4-isopropyl-1, 6-dimethylnaphthalene (CAS No. 483-78-3) is also 
known as cadalin or cadelene, and is found in the foliage and wood of 
trees, flowers, seeds, berries, hops and ferns:
     Chalchat et al., 1994. Journal of Essential Oil Research 
6(3): 323-325.
     Dodd et al., 1994. Biochemical Systematics and Ecology 
22(4): 393-400.
     El-Seedi et al., 1994. Phytochemistry 35(6): 1495-1497.
     Omata et al., 1990. Agricultural and Biological Chemistry 
54(4): 1029-1033.
     Ekundayo and Hammerschmidt, 1988. Fitoterapia 59(1): 52-
54.
     Lawerance, 1984. Perfume and Flavor 9(5): 65-69.
     Tressel et al., 1983. Journal of Agricultural and Food 
Chemistry 31(4): 892-897.
     Konecny et al., 1982. Collect. Czech. Chemistry 
Communications 47(11): 3164-3169).
    5. Comment 4. In the fourth comment, the correspondent points out 
that a rat metabolism study discussed in the 2, 6-
Diisopropylnaphthalene BRAD did not explain the ``fate of the remaining 
77% of the administered dose,'' and asks if the conditional livestock 
feeding study could account for it.
    EPA response. Although the submitted magnitude of the residue study 
in livestock was conducted in a reasonable manner, it was designed to 
determine the magnitude of 2, 6-DIPN residues (not residues from 2, 6-
DIPN metabolites) in cattle fed at up to 5.64 times the normal 
application rate, and only in milk and edible tissues. It did not, 
therefore, account for the fate of the remaining 77% of the 
administered dose from the earlier rat metabolism study. The rat 
metabolism study was also

[[Page 52006]]

designed to identify residues/metabolites of toxicological concern, and 
the absence of a complete accounting of the administered dose was a 
factor in determining the need for the livestock feeding study. 
Furthermore, the cattle feeding study cannot be expected to resolve 
metabolism questions arising from the rat data because the two species 
may metabolize 2, 6-DIPN differently. The Agency is therefore 
requiring, as a condition of registration, submission of a nature of 
the residue study to determine the fate of the dose (i.e., to determine 
the distribution of 2, 6-DIPN metabolites in livestock commodities), 
and a laboratory-validated multi-residue analytical method. However, 
because worst case (conservative) estimates were used to support the 
time-limited tolerances established in this rule, EPA has concluded 
that there is a reasonable certainty of no harm from the use of 2, 6-
DIPN during the short period while these studies are conducted.
    6. Comment 5. In this comment the correspondent observes from the 
notice of filing (December 9, 2005 (70 FR 73234) (FRL-7748-5)) that the 
petitioner is seeking use rates/tolerance levels higher than those 
actually tested in the submitted residue trials.
    EPA response. The cited notice includes a discussion of information 
and magnitude of the residue data previously submitted by the 
petitioner to support a related request to amend the label of the 2, 6-
DIPN end-use product, EPA Registration No. 34704-843. That data, on 
whole potato and potato peel, have been reviewed by the Agency and 
found to adequately demonstrate that 2, 6-DIPN residues in both 
commodities declined over time. Recalculations based on these storage 
stability data for analytical samples, the increased application rate, 
and more refined residue chemistry data including information on 
secondary residues in cattle fed 2, 6-DIPN treated potato waste 
resulted in significantly reduced risk (see discussion below and the 
previous notice of filing of December 9, 2005, cited above). The 
Agency's assessment of the new information (to project the residue 
levels expected to result from an increased application rate) supports 
the amended maximum yearly application rate of 1.5 (increased from 1.0) 
pounds of active ingredient per 600 hundred[fxsp0]weight of potato. 
Although the petitioner in their summary of PP 1F6338 referred to the 
proposed application rate as 1.5 pounds of product per 600 
hundred[fxsp0]weight of potato, any future references in this document 
to the application rate will be expressed as pounds of active 
ingredient per 600 hundred[fxsp0]weight of potato because (a) the end-
use product is 99.7% pure active ingredient, and (b) the subject of 
this rule is the active ingredient. Available residue data also provide 
adequate support to reduce the required period for holding treated 
stored potato from 30 to zero days because in its analysis the Agency 
considered data from samples collected on the day of treatment. The 
adequacy of all of this data will be re-evaluated upon review of a 
nature of the residue study for potato, which the Agency is requiring 
as another condition of registration.
    7. Comment 6. Comment six cites the 2, 6-Diisopropylnaphthalene 
BRAD (page 10) as stating that a developmental toxicity study in a 
second species and a reproduction toxicity study were not available to 
``...fully determine age-related differences in response.'' The 
correspondent requests we address this lack of data, and states in this 
comment, ``Since 2, 6-DIPN does not occur in nature, requirement of a 
reproduction study would be appropriate.''
    EPA response. As indicated in the response to comment 1 above, 2, 
6-DIPN was classified as a biochemical-like pesticide based on 
functional and structural similarity to certain plant regulators, thus 
qualifying for a reduced data set for registration (i.e., the data set 
required by 40 CFR 158.690 to support registration of biochemical or 
biochemical-like pesticides is reduced compared to that required for 
conventional chemical pesticides). In the absence of the full 
complement of developmental (in two species) and reproduction toxicity 
studies, an added 10x uncertainty factor was retained for the reference 
doses selected for dietary risk characterization. In addition, the 
developmental toxicity study of 2, 6-DIPN considered by the Agency did 
not indicate differences in sensitivity of maternal animals and their 
offspring. Given these circumstances, the Agency has adequately 
assessed age-related differences in responses to 2, 6-DIPN exposure by 
retaining the 10x uncertainty factor in lieu of the second 
developmental and reproduction toxicity studies.
    8. Comment 7. In this comment, the correspondent states that 2, 6-
DIPN is a pesticide for which pork may be tested under the U.S. 
Department of Agriculture's Pesticide Data Program, which was developed 
in coordination with the Agency's Health Effects Division, and asks (a) 
if 2, 6-DIPN residues in pork have been found, and (b) why the required 
livestock feeding study was limited to cattle.
    EPA response. No 2, 6-DIPN residues were found in pork because a 
study with swine was not requested by the Agency. The conditionally-
required livestock feeding study was limited to cattle in alignment 
with OPPTS Harmonized Guideline 860.1480, which states that, ``...in 
most cases the results of the cattle feeding study will be used to 
establish tolerances on goat, hog, horse, and sheep....'' This is 
because the overall percentage of the potato commodities in the diet of 
cattle is much higher than in the diet of swine (Table 1 of OPPTS 
Harmonized Guideline 860.1000). Furthermore, of those potato 
commodities utilized as feedstuffs, processed potato waste (i.e., 
potato, wet peel), where the majority of 2, 6-DIPN residue is expected 
to occur, can represent a high percentage of the diet for cattle, but 
is either not used, or used at less than 10%, in the diet for swine. 
Testing of cattle rather than swine, therefore, represents the more 
conservative, ``worst-case,'' scenario. Nonetheless, dietary 
contributions of residues from swine fed 2, 6-DIPN treated potato were 
factored into the Agency's dietary assessment by conservatively 
assuming the same levels in pork commodities as those found in cattle.
    9. Comment 8. In this comment the correspondent observes from the 
notice of filing (December 9, 2005 (70 FR 73234) (FRL-7748-5)) that, 
except at the highest dose level, the petitioner reported 2, 6-DIPN 
residues were not located in cow liver, an organ that usually 
concentrates exogenous chemicals as it metabolizes them. The Agency is 
asked to address if 2, 6-DIPN was radio-labeled for use in the cited 
livestock feeding study.
    EPA response. Unless their purpose is to determine the nature of 
the residue, feeding trials are conducted with standard analytical 
methods without radio-labeled test material for determining the 
presence of pesticide residues in meat, meat byproducts, milk, etc., to 
establish the need for tolerances in those commodities and to develop 
appropriate enforcement analytical methods. Radio-labeled test material 
is used to evaluate absorption, distribution, metabolism (nature of the 
residue), and excretion of an administered dose. Based on physical and 
chemical properties, 2, 6-DIPN is soluble in non-polar solvents (e.g., 
fat), making it unlikely that 2, 6-DIPN will accumulate in the liver of 
cattle fed treated potato waste. Also, in the livestock magnitude of 
the residue study, 2, 6-DIPN residues were found in higher levels in 
ruminant fat than liver. Tolerance levels in livestock

[[Page 52007]]

commodities were set accordingly. Should the conditionally-required 
metabolism (nature of the residue in livestock) study be submitted, if 
residues of 2, 6-DIPN and its metabolite(s) are found at some higher 
level in cow liver, the Agency will re-evaluate its tolerance decision 
based upon a new risk assessment revised to incorporate data on such 
increased residues in cow liver. However, the existing residue data do 
not indicate that 2, 6-DIPN accumulates in livestock liver.
    10. Comment 9. In this comment, the Agency is requested to assess 
risk and exposure to 2, 6-DIPN using both a ``local milkshed'' and a 
national average scenario (to account for the feeding of potato waste 
containing pesticide residues to local cattle, from which meat/milk is 
locally distributed), as was done in the Reregistration Eligibility 
Document (page 25) for the conventional chemical, chlorpropham.
    EPA response. The ``local milkshed'' scenario assumes that finite 
residues may be expected in milk and liver consumed by individuals 
living in a highly localized area where cattle may be fed processed 
potato waste from nearby potato processing plants (i.e., higher 
exposure may be expected in rural communities where cattle are fed 
peelings from treated potato). In the case of 2, 6-DIPN, since the 
national average scenario is already based on a very conservative, 
``worst case,'' scenario (that all potato nationwide are treated), 
there is no need to duplicatively use a ``local milkshed'' scenario, 
which also represents the worst case.
    11. Comment 10. In this comment, the correspondent states that 
diisopropylnaphthalenes have commercial uses (primarily paper 
production) in the U.S., and asks the Agency to address whether 
aggregate exposure is likely and if the non-pesticidal commercial uses 
of 2, 6-DIPN are likely to contribute to consumer exposure.
    EPA response. Section 408 (b)(2)(A)(ii) explicitly requires the 
Agency to find that ``there is a reasonable certainty that no harm will 
result from aggregate exposures, including all anticipated dietary 
exposures and all other exposures for which there is reliable 
information.'' As discussed below, EPA has considered all available 
information on non-dietary and non-occupational exposures in 
establishing these time-limited tolerances. There is no potential for 
exposure to residues of 2, 6-DIPN in drinking and ground water as a 
result of application to potato stored in warehouses, where the 
pesticide remains until the storage area is ventilated and 2, 6-DIPN 
has degraded somewhat or evaporated. The FQPA requires conduct of an 
aggregate risk assessment, considering all non-occupational sources, 
including exposure from water, food, and residential use. But since 
there are no registered residential or water uses, an aggregate 
assessment for 2, 6-DIPN is not required. Pesticidal uses only are 
aggregated; non-pesticide uses (i.e., the commercial uses identified in 
the comment) are not part of this analysis.
    Section 408(b)(2)(A)(i) of the FFDCA allows EPA to establish a 
tolerance (the legal limit for a pesticide chemical residue in or on a 
food) only if EPA determines that the tolerance is ``safe.'' Section 
408(b)(2)(A)(ii) of the FFDCA defines ``safe'' to mean that ``there is 
a reasonable certainty that no harm will result from aggregate exposure 
to the pesticide chemical residue, including all anticipated dietary 
exposures and all other exposures for which there is reliable 
information.'' This includes exposure through drinking water and in 
residential settings, but does not include occupational exposure. 
Section 408(b)(2)(C) of the FFDCA requires EPA to give special 
consideration to exposure of infants and children to the pesticide 
chemical residue in establishing a tolerance and to ``ensure that there 
is a reasonable certainty that no harm will result to infants and 
children from aggregate exposure to the pesticide chemical 
residue....''
    EPA performs a number of analyses to determine the risks from 
aggregate exposure to pesticide residues. For further discussion of the 
regulatory requirements of section 408 of the FFDCA and a complete 
description of the risk assessment process, see http://www.epa.gov/fedrgstr/EPA-PEST/1997/November/Day-26/p30948.htm
.

III. Aggregate Risk Assessment and Determination of Safety

    Consistent with section 408(b)(2)(D) of the FFDCA, EPA has reviewed 
the available scientific data and other relevant information in support 
of this action. EPA has sufficient data to assess the hazards of, and 
to make a determination on aggregate exposure, consistent with section 
408(b)(2) of the FFDCA, for time-limited tolerances for residues of 2, 
6-DIPN, resulting from post-harvest applications to potato, in or on 
fat (cattle, goat, hog, horse, sheep) at 0.8 ppm; liver (cattle, goat, 
hog, horse, sheep) at 0.3 ppm; meat (cattle, goat, hog, horse, sheep) 
at 0.1 ppm; meat byproducts (cattle, goat, hog, horse, sheep) at 0.1 
ppm; milk at 0.1 ppm; potato at 2.0 ppm; and potato, wet peel at 6.0 
ppm. EPA's assessment of the dietary exposures and risks associated 
with establishing the time-limited tolerances follows.

A. Toxicological Profile

    EPA has previously evaluated the available toxicity data and 
considered its validity, completeness, and reliability as well as the 
relationship of the results of the studies to human health risk. EPA 
has also considered available information concerning the variability of 
the sensitivities of major identifiable subgroups of consumers, 
including infants and children.
    In the Federal Register of August 8, 2003 (68 FR 47246) (FRL-7321-
61), EPA established time-limited tolerances (which were throughout 
that final rule erroneously referred to as temporary tolerances) for 
residues of the plant regulator 2, 6-diisopropylnaphthalene (2, 6-DIPN) 
in or on the food commodities meat, meat byproducts, milk, potato 
(peel) and potato (whole) at 1.35, 1.35, 0.7, 3, and 0.5 ppm, 
respectively. Although not explicitly noted in the tolerance expression 
(40 CFR 180.590) that these time-limited tolerances were limited to 2, 
6-DIPN residues resulting from post-harvest application to potato, that 
fact was implicitly noted throughout the final rule itself. 
Nonetheless, this oversight is explicitly corrected in the new 
tolerance expression for 2, 6-DIPN set forth in this final rule.
    The August 8, 2003 final rule included a summary of the Agency's 
assessment of the health effects data submitted by the applicant, who 
was seeking an exemption from the requirement of a tolerance, as 
opposed to the time-limited numeric tolerances that the Agency 
ultimately granted. Although the toxicity data do not indicate extra 
sensitivity of offspring when compared with that of adult animals, due 
to the application of uncertainty factors the data base does represent 
a conservative FQPA assessment of potential age-related sensitivity or 
acute effects other than lethality, notwithstanding the absence of a 
developmental toxicity study in a second species, a multi-generation 
reproduction toxicity study, or a range of doses adequate to induce a 
full range of toxic responses (especially, potential acute effects in 
any of the available studies). However, because 2, 6-DIPN has been 
classified by the Agency as a biochemical-like active ingredient, it is 
subject to a reduced data set which does not include the cited 
developmental and reproductive toxicity data. Instead, the FQPA 
criteria concerning the potential extra sensitivity of infants and 
children

[[Page 52008]]

may be met by the application of a safety factor. Therefore, the August 
8, 2003 final rule also announced that, in considering the sensitivity 
of infants and children, the thousandfold safety factor (10x for 
interspecies extrapolation, 10x for intraspecies variability and the 
10x default safety factor) includes the retention of the FQPA default 
tenfold uncertainty factor, which (in lieu of the cited data) 
adequately accounts for age-related sensitivity for the subpopulations 
of infants and children. The expiration date of the time-limited 
tolerances was May 31, 2006.
    Summaries of the toxicological profile and other relevant health 
effects data, in compliance with the requirements of the FFDCA, as 
amended by the FQPA of 1996, were reported in the August 8, 2003, 
Federal Register publication of the final rule establishing the time-
limited tolerances. Although the petitioner has not submitted the 
conditionally-required independent laboratory validation of the 
enforcement analytical methods and there is a newly-identified data gap 
(nature of the residue in plants and livestock), based on (1) the 
previously submitted data outlined in the August 8, 2003 Federal 
Register final rule, and the rationale included therein, and (2) the 
Agency's assessment of results from the new magnitude of the residue in 
livestock study; the analytical enforcement methods to determine 
residue in potato, potato peels and livestock commodities; and the 
magnitude of the residue submission which presented recalculations of 
previously submitted data to support proposed label amendments, EPA 
concludes that there is a reasonable certainty that no harm will result 
from aggregate exposure to the U.S. population, including infants and 
children, to 2, 6-DIPN, during the time period for which these time-
limited tolerances are established. This includes all anticipated 
dietary exposures and all other exposures for which there is reliable 
information.
    The conditionally-required magnitude of the residue study in 
livestock (MRID 464650-01) involved testing at three dose levels in 
dairy cattle. The dose levels were multiples (1x, 3x, and 10x) of the 9 
ppm maximum theoretical dietary burden (MTDB) for dairy cattle which 
was based on the original time-limited tolerances of 0.5 and 3 ppm in/
on whole potato and potato peels, respectively. Since the proposed 
tolerances are 2.0 ppm in or on potato and 6.0 ppm in or on potato, wet 
peel, the multiples of the revised MTDB (16 ppm) are 0.56x, 1.59x, and 
5.64x. The highest residue levels were found in fat (0.095 ppm at 
0.56x, 0.2 ppm at 1.59x and 0.74 ppm at 5.64x). The second highest 
residue levels were found in milk cream (0.17 ppm at 5.64x). Whole milk 
residue levels plateaued at approximately 0.025 ppm after 4 days' 
feeding of the 5.64x test diet. At the end of the 29-day feeding study, 
the residue levels of 2, 6-DIPN were at 0.033, 0.035, and 0.23 ppm in 
milk, kidney, and liver, respectively at the 5.64x feeding level. 
Although the highest multiple of the MTDB tested was fivefold to 
sixfold, rather than the tenfold recommended in OPPTS Harmonized 
Guideline 860.1480, the trial itself was conducted in a reasonable 
manner. In the end, residues were found at levels below the proposed 
time-limited tolerance levels for those matrices at an application rate 
similar to the proposed new rate of 1.5 pounds of active ingredient per 
600 hundred[fxsp0]weight of potato. The assumption of 100% crop treated 
and the use of the results from the 5.64x dietary level provides an 
adequate basis for estimating dietary exposures in the assessment of 
potential risks associated with the normal (i.e., in accordance with 
good agricultural practices) post-harvest use of 2, 6-DIPN on stored 
potato as directed on the product label.
    The analytical methods submitted to enforce the time-limited 
tolerance levels established for 2, 6-DIPN residues in potato, potato 
peels, and in livestock commodities (MRIDs 464749-01, 464749-02, and 
464650-02, respectively) are adequate for the purpose of this extension 
and amendment of the time-limited tolerances for 2, 6-DIPN. Validation 
of these methods by an independent laboratory remains a condition of 
registration and must be submitted to the Agency for review in advance 
of the new time-limited tolerance expiration date of August 1, 2009. 
Furthermore, should the newly-imposed conditional data (nature of the 
residue in plants and livestock) be performed, an independently 
validated multi-residue laboratory method must be submitted to the 
Agency for review in advance of the expiration date of August 1, 2009 
for the new time-limited tolerances.
    The study in which previously submitted magnitude of the residue 
data were recalculated (MRID 466005-01) to project residue levels for 
the proposed increased application rate (from 1.0 to 1.5 lbs of active 
ingredient per 600 hundred[fxsp0]weight of potato) adequately supports 
the new maximum yearly application rate (which may be applied via 
multiple treatments). Also acceptable is a proposal to reduce from 30 
to zero days the required period for holding treated stored potato. The 
highest residues of 2, 6-DIPN are 1.59 ppm for potato and 5.06 ppm for 
potato peel at the zero day sampling. Since the proposed tolerance 
levels exceed the extrapolated maximum residue values for the increased 
application rate, the estimated risk characterization does not exceed 
our level of concern.

B. Toxicological Endpoints

    1. Acute toxicity. EPA's discussion and analysis of acute toxicity 
of 2, 6-DIPN can be found in the Federal Register of August 8, 2003 (68 
FR 47246) (FRL-7321-61).
    2. Short- and intermediate-term toxicity. EPA's discussion and 
analysis of short- and intermediate-term toxicity of 2, 6-DIPN can be 
found in the Federal Register of August 8, 2003 (68 FR 47246) (FRL-
7321-61). Based on the information summarized in that final rule, the 
104 mg/kg/day NOAEL is selected as the endpoint for this assessment.
    3. Chronic toxicity. EPA has established the Reference Dose (RfD) 
for 2, 6-DIPN at 1 mg/kg/day. This RfD is based on results from the 
subchronic and developmental toxicity studies described above.
    4. Carcinogenicity. No study results suggest that 2, 6-DIPN is 
carcinogenic. See the EPA's discussion and analysis in the Federal 
Register of August 8, 2003 (68 FR 47246) (FRL-7321-61).

C. Exposures and Risks

    1. From food and feed uses. Tolerances have been established (40 
CFR 180.590) for the residues of 2, 6-DIPN, resulting from post-harvest 
applications to potato, in or on a variety of food commodities: fat 
(cattle, goat, hog, horse, and sheep) at 0.8 ppm; liver (cattle, goat, 
hog, horse, and sheep) at 0.3 ppm; meat (cattle, goat, hog, horse, and 
sheep) at 0.1 ppm; meat byproducts (cattle, goat, hog, horse, and 
sheep) at 0.1 ppm; milk at 0.1 ppm; potato at 2.0 ppm; and potato, wet 
peel at 6.0 ppm. Risk assessments were conducted by EPA to assess 
dietary exposures from 2, 6-DIPN. These assessments were based on 100% 
crop treated, maximum label application rate, and used the tolerance 
levels (which exceeded reported residue levels).
    Acute dietary risk assessments are performed for a food-use 
pesticide if a toxicological study has indicated the possibility of an 
effect of concern occurring as a result of a 1-day or single exposure. 
In the case of 2, 6-DIPN, the limited toxicity data base did not 
indicate an acute endpoint, but the 100 mg/kg/day NOAEL from the 
subchronic toxicity study (rounded from 104 mg/kg/day) was used to 
evaluate potential

[[Page 52009]]

acute dietary exposure as a conservative basis for risk 
characterization. Also, if the 50 mg/kg/day NOAEL from the 
developmental toxicity study had been used to establish an acute RfD, 
this choice would have been inconsistent with the use of the 100 mg/kg/
day NOAEL since it implies that exposure to repeated daily doses at 100 
mg/kg/day is potentially less hazardous than a single dose at 50 mg/kg/
day. Given the minimal nature of the responses in the subchronic and 
developmental toxicity studies and the fact that the NOAEL from the 
developmental study is only appropriate to the subgroup of females 13-
49 years of age, using the 100 mg/kg/day RfD for the acute and chronic 
dietary assessments is more appropriate for assessing risk for other 
subgroups and the general population. Therefore, a conservative 
interpretation of these endpoints indicated the need for an acute 
dietary exposure assessment. The 100 mg/kg/day endpoint was also 
interpreted as requiring a chronic dietary exposure assessment.
    Acute and chronic dietary exposure assessments for 2, 6-DIPN were 
conducted using the Dietary Exposure Evaluation Model software 
(DEEMTM version 1.30) which incorporates consumption data 
from USDA's Continuing Surveys of Food Intakes by Individuals (CSFII, 
1994-1996/1998).
    For acute exposure assessments, individual 1-day food consumption 
data define an exposure distribution which is expressed as a percentage 
of the acute population adjusted dose (for 2, 6-DIPN, aPAD = 0.1 mg/
kg). For chronic exposure and risk assessment, an estimate of the 
residue level in each food or food-form (e.g., orange or orange juice) 
on the commodity residue list is multiplied by the average daily 
consumption estimate for the food or food-form. The resulting residue 
consumption estimate for each food or food-form is summed with the 
residue consumption estimate for all other food or food-forms on the 
commodity residue list to arrive at the total estimated exposure. 
Exposure estimates are expressed as mg/kg body weight/day and as a 
percent of the 2, 6-DIPN cPAD (0.1 mg/kg/day). These procedures are 
performed for each population subgroup.
    2. From drinking water. Because 2, 6-DIPN treatment of stored 
(i.e., post-harvest) potato occurs inside (in warehouses, for example), 
no concern from exposure through water is expected regarding acute and 
chronic dietary risk assessment. For this reason, the dietary risk 
assessment did not include drinking water values.
    3. From non-dietary exposure. The term ``residential exposure'' is 
used in this document to refer to non-occupational, non-dietary 
exposure (e.g., for lawn and garden pest control, indoor pest control, 
termiticides, and flea and tick control on pets). 2, 6-DIPN is not 
registered for use on any sites that would result in residential 
exposure. Furthermore, because the registered use involves applications 
via a closed system, no exposure of consequence is expected to mixers 
or loaders.
    4. Cumulative effects from substances with a common mechanism of 
toxicity. Section 408(b)(2)(D)(v) of the FFDCA requires that, when 
considering whether to establish, modify, or revoke a tolerance, the 
Agency consider ``available information'' concerning the cumulative 
effects of a particular pesticide's residues and ``other substances 
that have a common mechanism of toxicity.''
    Unlike other pesticides for which EPA has followed a cumulative 
risk approach based on a common mechanism of toxicity, EPA has not made 
a common mechanism of toxicity finding as to 2, 6-DIPN and any other 
substances. In this case, 2, 6-DIPN and the three functionally and 
structurally similar substances all act as plant regulators by a ``mode 
of action'' that is specific to plants, and therefore, their common 
mode of action is unlikely to be relevant to a mechanism of toxicity in 
animals or humans. The comparison of 2, 6-DIPN with three naturally 
occurring alkyl substituted naphthalenes is made to demonstrate 
biological activity (plant regulation, in this case), which the Agency 
has characterized as a non-toxic mode of action with respect to 
pesticidal activity. For the purposes of this tolerance action, 
therefore, EPA has not assumed that 2, 6-DIPN has a common mechanism of 
toxicity with other substances. For information regarding EPA's efforts 
to determine which chemicals have a common mechanism of toxicity and to 
evaluate the cumulative effects of such chemicals, see the policy 
statements released by EPA's Office of Pesticide Programs concerning 
common mechanism determinations and procedures for cumulating effects 
from substances found to have a common mechanism on EPA's Web site at 
http://www.epa.gov/pesticides/cumulative.

D. Aggregate Risks and Determination of Safety for U.S. Population and 
for Infants and Children

    1. Acute risk. Acute dietary exposure estimates were based on the 
tolerances (supported by the residue trial results, i.e. the tolerance 
levels as established in this final rule) and worst-case assumptions.
    As reported in the Federal Register of August 8, 2003 (68 FR 47246) 
(FRL-7321-61), EPA established a RfD of 1 mg/kg/day, and the aPAD and 
cPAD at 0.1 mg/kg/day.
    For the U.S. population, acute dietary exposure was estimated to be 
0.009167 mg/kg/day. This value represented 9.17% of the aPAD (27.5% if 
the aPAD is calculated using the same uncertainty factor of 3,000 as 
that described above for the IRIS assessment of naphthalene; aPAD = 
0.033 mg/kg). The subpopulation with the highest acute dietary exposure 
estimate was children 1 to 2 years of age (0.022197 mg/kg/day, 22.20% 
of the aPAD; 66.6% when using the IRIS adjustment). If the 50 mg/kg/day 
NOAEL from the developmental toxicity study is used to derive an aPAD, 
the exposure for the subgroup females 13 to 49 years of age (0.006701 
mg/kg/day) represented 6.7% of the subgroup-specific aPAD (0.05 mg/kg); 
this subgroup's exposure represented 13.4% of the 0.05 mg/kg aPAD. 
Therefore, the acute dietary exposures to all the subpopulations in the 
analysis did not exceed EPA's level of concern (>100% of the aPAD).
    These dietary exposure estimates based on the 0.1 mg/kg/day aPAD 
are less than previously described by the Agency. For example, the 
previous estimated dietary exposure for the general U.S. population was 
0.023113 mg/kg/day which is slightly more than twice the current 
estimate. Residue data have been refined and, accordingly, support 
revised tolerances (meat, meat byproducts and milk tolerances decrease 
and new livestock commodities liver and fat are added based upon the 
low or undetected residues from the livestock feeding trial; potato and 
potato, wet peel tolerances increase based upon the residue data and 
increased application rate) as follows: the previous tolerance on 
potato (0.5 ppm) increases to 2.0 ppm; the 3 ppm tolerance on potato, 
wet peel, increases to 6.0 ppm; the 1.35 ppm tolerances for meat and 
meat byproducts decrease to 0.1 ppm; the milk tolerance of 0.7 ppm 
drops to 0.1 ppm; and tolerances for liver (0.3 ppm) and fat (0.8 ppm) 
are added. Overall, these revised tolerances have significantly reduced 
estimated dietary exposures and the associated potential risks when 
calculations are based on the 0.1 mg/kg/day aPAD.
    2. Chronic risk. EPA has concluded that the chronic dietary 
exposure estimates based on the 0.1 mg/kg/day cPAD are also less than 
previously described. For example, the previous

[[Page 52010]]

chronic dietary exposure estimate for the general population was 
0.006939 mg/kg/day, which is more than twice the current estimate of 
0.002718 mg/kg/day (2.7% of the cPAD). The subpopulation with the 
highest chronic dietary exposure estimate was children 1 to 2 years of 
age, with estimated exposures of 0.008068 mg/kg/day, which constitutes 
8.1% of the cPAD. The previous chronic exposure estimates were more 
than twice the values determined in the current exposure assessment for 
the same reasons (refinements due to the availability of additional 
data, and increased application rate) as for the dietary exposure 
estimates described above. The chronic dietary exposures to all the 
subpopulations, as estimated in 2003, and the current, even lower, 
values estimated herein, do not exceed the Agency's level of concern.
    3. Determination of safety. Based on these risk assessments, EPA 
concludes that there is a reasonable certainty that no harm will result 
to the U. S. population, including infants and children, from aggregate 
exposure to residues of 2, 6-DIPN resulting from post-harvest 
applications, undertaken in accordance with good agricultural practices 
and label directions, to potato. This includes all anticipated dietary 
exposures and all other exposures for which there is reliable 
information. In arriving at this conclusion, and as stated earlier in 
Unit III.A. of this preamble, it is important to re-emphasize that EPA, 
pursuant to FFDCA section 408(b)(2)(C), has retained the tenfold margin 
of exposure in order to adequately account for potential pre- and post-
natal toxicity and completeness of the data with respect to exposure 
and toxicity to infants and children.

IV. Other Considerations

A. Metabolism in Plants and Animals

    The nature of the residue in stored potato is not adequately 
understood for the purpose of establishing non-time-limited/permanent 
tolerances. The regulation at 40 CFR 158.690(a) requires that nature of 
the residue data be submitted for plants when the application rate of 
the product exceeds a level determined to be comparable to 0.7 ounces 
active ingredient per application (when the application rate is not 
expressed in terms of ounces per acre per application). Calculations 
based on Agriculture Statistics 2005 indicate that the new maximum 
single application rate of 1.5 pounds active ingredient per 600 
hundred[fxsp0]weight of potato is approximately equal to 14 ounces of 
active ingredient per acre per application, thus triggering the data 
requirement. A study conducted in accordance with OPPTS Harmonized 
Guideline 860.1300 is conditionally required to determine the 
residue(s) of concern in or on stored potato treated with 2, 6-DIPN, 
and must be submitted so as to permit an Agency decision on its 
adequacy in advance of the August 1, 2009 expiration date for the time-
limited tolerances.
    The nature of the residue in livestock is not adequately understood 
for the purpose of establishing non-time-limited/permanent tolerances. 
The submitted metabolism study showed the total urinary excretion of 2, 
6-DIPN metabolites to be about 23% of the administered dose, while the 
fate of the the remaining 60% or 77% of the administered dose was 
unexplained. Submission of a nature of the residue study in livestock 
is conditionally required based on the same application rate criteria 
discussed above for the nature of the residue in plants requirement. A 
study conducted in accordance with OPPTS Harmonized Guideline 860.1300 
is conditionally required to determine the distributions of residue(s) 
of 2, 6-DIPN and its metabolites in livestock commodities, and must be 
submitted so as to permit an Agency decision on its adequacy in advance 
of the August 1, 2009 expiration date for the time-limited tolerances.
    Any multi-residue methods developed in conjunction with these 
conditionally required nature of the residue studies (in plants and 
livestock) must be validated by an independent laboratory and also be 
submitted so as to permit an Agency decision on adequacy in advance of 
the August 1, 2009 expiration date for the time-limited tolerances.
    Notwithstanding these data gaps and conditions of registration, the 
EPA has determined, based on the available toxicological data, the 
thousandfold uncertainty factor, and the levels of exposure, that there 
is a reasonable certainty that no harm will result to the U.S. 
population, including infants and children, from aggregate exposure to 
the pesticide (2, 6-DIPN) and its residues during the period of the 
time-limited tolerances.

B. Analytical Enforcement Methodology

    High Performance Liquid Chromatography (HPLC)/Ultraviolet(UV) and 
gas chromatography (GC)/Mass Spectroscopy (MS) methods were used to 
measure the levels of 2, 6-DIPN in the residue studies. However, as a 
condition of the registration granted for 2, 6-DIPN on July 31, 2003, 
the petitioner was required to submit an independent laboratory 
validation (ILV) of the analytical enforcement method(s) used to detect 
residues of 2, 6-DIPN in potato and livestock food commodities. Because 
these data have not been submitted, the ILV remains a condition of 
registration for 2, 6-DIPN. Furthermore, a newly-imposed condition of 
registration is the submission of nature of the residue data for plants 
and livestock, and the Agency is placing a 3-year time-limitation on 
the established numeric tolerances. Multi-residue method(s) associated 
with those conditional data are required, and also must be validated by 
an independent laboratory. During this 3-year time period the 
petitioner must supply all the required ILV, allowing adequate time 
from its submission to permit the Agency's review and decision in 
advance of the August 1, 2009 expiration date for the time-limited 
tolerances.

C. International Residue Limits

    There are no Codex Alimentarius Commission (Codex) Maximum Residue 
Levels (MRLs) for residues of 2, 6-DIPN.

V. Conclusion

    A data gap currently exists for an independent laboratory 
validation (ILV) of the analytical enforcement method(s) used to detect 
residues of 2, 6-DIPN in potato and livestock food commodities, because 
the petitioner failed to submit these data as was required by a 
condition of the July 31, 2003 registration of 2, 6-DIPN. There is also 
imposed a new condition of registration; nature of the residue in 
plants and livestock must be submitted. Any multi-residue method(s) 
developed in association with these conditionally required data must 
also be validated by an independent laboratory. All tolerances are 
time-limited because of these data gaps. The time limitation allows for 
conduct, submission, and review of the data. Notwithstanding these data 
gaps and conditions of registration, the EPA has determined, based on 
the available toxicological data, the thousandfold uncertainty factor, 
and the levels of exposure, that there is a reasonable certainty that 
no harm will result to the U.S. population, including infants and 
children, from aggregate exposure to the pesticide (2, 6-DIPN) and its 
residues during the period of the time-limited tolerances.
    Based on the information and rationale cited in the final rule of 
August 8, 2003, plus the results of the new magnitude of the residue in 
livestock study; the analytical enforcement methods to determine

[[Page 52011]]

residue in potato, potato peel and livestock commodities; and the 
magnitude of the residue submission which presented recalculations of 
previously submitted data to support proposed label amendments, the 
Agency has determined that the establishment of the time-limited 
tolerances by amending 40 CFR 180.590 in the manner set forth in this 
final rule will be safe.
    Therefore, the following time-limited tolerances are established 
for residues of 2, 6-DIPN in or on the following commodities resulting 
from post-harvest applications to potato: fat (cattle, goat, hog, 
horse, and sheep) at 0.8 ppm; liver (cattle, goat, hog, horse, and 
sheep) at 0.3 ppm; meat (cattle, goat, hog, horse, and sheep) at 0.1 
ppm; meat byproducts (cattle, goat, hog, horse, and sheep) at 0.1 ppm; 
milk at 0.1 ppm; potato at 2.0 ppm; and potato, wet peel at 6.0 ppm.

VI. Statutory and Executive Order Reviews

    This final rule establishes time-limited tolerances under section 
408(d) of the FFDCA in response to a petition submitted to the Agency. 
The Office of Management and Budget (OMB) has exempted these types of 
actions from review under Executive Order 12866, entitled Regulatory 
Planning and Review (58 FR 51735, October 4, 1993). Because this rule 
has been exempted from review under Executive Order 12866 due to its 
lack of significance, this rule is not subject to Executive Order 
13211, Actions Concerning Regulations That Significantly Affect Energy 
Supply, Distribution, or Use (66 FR 28355, May 22, 2001). This final 
rule does not contain any information collections subject to OMB 
approval under the Paperwork Reduction Act (PRA), 44 U.S.C. 3501 et 
seq., or impose any enforceable duty or contain any unfunded mandate as 
described under Title II of the Unfunded Mandates Reform Act of 1995 
(UMRA) (Public Law 104-4). Nor does it require any special 
considerations under Executive Order 12898, entitled Federal Actions to 
Address Environmental Justice in Minority Populations and Low-Income 
Populations (59 FR 7629, February 16, 1994); or OMB review or any 
Agency action under Executive Order 13045, entitled Protection of 
Children from Environmental Health Risks and Safety Risks (62 FR 19885, 
April 23, 1997). This action does not involve any technical standards 
that would require Agency consideration of voluntary consensus 
standards pursuant to section 12(d) of the National Technology Transfer 
and Advancement Act of 1995 (NTTAA), Public Law 104-113, section 12(d) 
(15 U.S.C. 272 note). Since tolerances and exemptions that are 
established on the basis of a petition under section 408(d) of the 
FFDCA, such as the time-limited tolerances in this final rule, do not 
require the issuance of a proposed rule, the requirements of the 
Regulatory Flexibility Act (RFA) (5 U.S.C. 601 et seq.) do not apply. 
In addition, the Agency has determined that this action will not have a 
substantial direct effect on States, on the relationship between the 
national government and the States, or on the distribution of power and 
responsibilities among the various levels of government, as specified 
in Executive Order 13132, entitled Federalism (64 FR 43255, August 10, 
1999). Executive Order 13132 requires EPA to develop an accountable 
process to ensure ``meaningful and timely input by State and local 
officials in the development of regulatory policies that have 
federalism implications.'' ``Policies that have federalism 
implications'' is defined in the Executive order to include regulations 
that have ``substantial direct effects on the States, on the 
relationship between the national government and the States, or on the 
distribution of power and responsibilities among the various levels of 
government.'' This final rule directly regulates growers, food 
processors, food handlers and food retailers, not States. This action 
does not alter the relationships or distribution of power and 
responsibilities established by Congress in the preemption provisions 
of section 408(n)(4) of the FFDCA. For these same reasons, the Agency 
has determined that this rule does not have any ``tribal implications'' 
as described in Executive Order 13175, entitled Consultation and 
Coordination with Indian Tribal Governments (65 FR 67249, November 6, 
2000). Executive Order 13175, requires EPA to develop an accountable 
process to ensure ``meaningful and timely input by tribal officials in 
the development of regulatory policies that have tribal implications.'' 
``Policies that have tribal implications'' is defined in the Executive 
order to include regulations that have ``substantial direct effects on 
one or more Indian tribes, on the relationship between the Federal 
Government and the Indian tribes, or on the distribution of power and 
responsibilities between the Federal Government and Indian tribes.'' 
This rule will not have substantial direct effects on tribal 
governments, on the relationship between the Federal Government and 
Indian tribes, or on the distribution of power and responsibilities 
between the Federal Government and Indian tribes, as specified in 
Executive Order 13175. Thus, Executive Order 13175 does not apply to 
this rule.

VII. Congressional Review Act

    The Congressional Review Act, 5 U.S.C. 801 et seq., as added by the 
Small Business Regulatory Enforcement Fairness Act of 1996, generally 
provides that before a rule may take effect, the agency promulgating 
the rule must submit a rule report, which includes a copy of the rule, 
to each House of the Congress and to the Comptroller General of the 
United States. EPA will submit a report containing this rule and other 
required information to the U.S. Senate, the U.S. House of 
Representatives, and the Comptroller General of the United States prior 
to publication of this final rule in the Federal Register. This final 
rule is not a ``major rule'' as defined by 5 U.S.C. 804(2).

List of Subjects in 40 CFR Part 180

    Environmental protection, Administrative practice and procedure, 
Agricultural commodities, Pesticides and pests, Reporting and 
recordkeeping requirements.

    Dated: July 14, 2006.
Janet L. Andersen,
Director, Biopesticides and Pollution Prevention Division, Office of 
Pesticide Programs.

0
Therefore, 40 CFR chapter I is amended as follows:

PART 180--[AMENDED]

0
1. The authority citation for part 180 continues to read as follows:

    Authority: 21 U.S.C. 321(q), 346a and 371.

0
2. Section 180.590 is revised to read as follows:

Sec.  180.590  2, 6-Diisopropylnaphthalene (2, 6-DIPN); tolerances for 
residues.

    (a) General. Time-limited tolerances are established for residues 
of 2, 6-DIPN in or on the following commodities resulting from post-
harvest applications to potato, when 2, 6-DIPN is used in accordance 
with good agricultural practices:

------------------------------------------------------------------------
                                                             Expiration/
                   Commodity                     Parts per    revocation
                                                  million        date
------------------------------------------------------------------------
Cattle, fat...................................          0.8       8/1/09
Cattle, liver.................................          0.3       8/1/09
Cattle, meat..................................          0.1       8/1/09
Cattle, meat byproducts.......................          0.1       8/1/09
Goat, fat.....................................          0.8       8/1/09
Goat, liver...................................          0.3       8/1/09

[[Page 52012]]

Goat, meat....................................          0.1       8/1/09
Goat, meat byproducts.........................          0.1       8/1/09
Hog, fat......................................          0.8       8/1/09
Hog, liver....................................          0.3       8/1/09
Hog, meat.....................................          0.1       8/1/09
Hog, meat byproducts..........................          0.1       8/1/09
Horse, fat....................................          0.8       8/1/09
Horse, liver..................................          0.3       8/1/09
Horse, meat...................................          0.1       8/1/09
Horse, meat byproducts........................          0.1       8/1/09
Milk..........................................          0.1       8/1/09
Potato........................................          2.0       8/1/09
Potato, wet peel..............................          6.0       8/1/09
Sheep, fat....................................          0.8       8/1/09
Sheep, liver..................................          0.3       8/1/09
Sheep, meat...................................          0.1       8/1/09
Sheep, meat byproducts........................          0.1       8/1/09
------------------------------------------------------------------------

    (b) Section 18 emergency exemptions. [Reserved]
    (c) Tolerances with regional registrations. [Reserved]
    (d) Indirect or inadvertent residues. [Reserved]
[FR Doc. E6-14545 Filed 8-31-06; 8:45 am]

BILLING CODE 6560-50-S