[Federal Register Volume 64, Number 188 (Wednesday, September 29, 1999)]
[Rules and Regulations]
[Pages 52450-52457]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-25312]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 180

[OPP-300921; FRL-6382-1]
RIN 2070-AB78


Diflubenzuron; Pesticide Tolerances for Emergency Exemptions

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: This regulation establishes a time-limited tolerance for 
residues of diflubenzuron (N-[[4-

[[Page 52451]]

chlorophenyl)amino]-carbonyl]-2,6-difluorobenzamide) and its 
metabolites PCA (4-chloroaniline) and CPU (4-chlorophenylurea), 
expressed as parent compound in or on pears. This action is in response 
to EPA's granting of an emergency exemption under section 18 of the 
Federal Insecticide, Fungicide, and Rodenticide Act authorizing use of 
the pesticide on pears. This regulation establishes a maximum 
permissible level for residues of diflubenzuron in this food commodity. 
The tolerance will expire and is revoked on March 31, 2001.

DATES: This regulation is effective September 29, 1999. Objections and 
requests for hearings, identified by docket control number OPP-300921, 
must be received by EPA on or before November 29, 1999.

ADDRESSES: Written objections and hearing requests may be submitted by 
mail, in person, or by courier. Please follow the detailed instructions 
for each method as provided in Unit VII. of the ``SUPPLEMENTARY 
INFORMATION'' section. To ensure proper receipt by EPA, your objections 
and hearing requests must identify docket control number OPP-300921 in 
the subject line on the first page of your response.

FOR FURTHER INFORMATION CONTACT: By mail:Andrea Beard, Registration 
Division (7505C), Office of Pesticide Programs, Environmental 
Protection Agency, 401 M St., SW., Washington, DC 20460; telephone 
number: (703)308-9356; and e-mail address: [email protected].

SUPPLEMENTARY INFORMATION:

I. General Information

A. Does this Action Apply to Me?

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

 
------------------------------------------------------------------------
                                                          Examples of
           Categories                    NAICS            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 in the ``FOR FURTHER INFORMATION 
CONTACT'' section.

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'' 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 OPP-300921. The official record 
consists of the documents specifically referenced in this action, 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 Hwy., 
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.

II. Background and Statutory Findings

    EPA, on its own initiative, in accordance with sections 408 (l)(6) 
of the Federal Food, Drug, and Cosmetic Act (FFDCA), 21 U.S.C. 346a, is 
establishing a tolerance for residues of the insecticide diflubenzuron 
and its metabolites PCA and CPU, expressed as parent compound, in or on 
pears at 0.5 part per million (ppm). This tolerance will expire and is 
revoked on March 31, 2001. EPA will publish a document in the Federal 
Register to remove the revoked tolerance from the Code of Federal 
Regulations.
    Section 408(l)(6) of the FFDCA requires EPA to establish a time-
limited tolerance or exemption from the requirement for a tolerance for 
pesticide chemical residues in food that will result from the use of a 
pesticide under an emergency exemption granted by EPA under section 18 
of FIFRA. Such tolerances can be established without providing notice 
or period for public comment. EPA does not intend for its actions on 
section 18 related tolerances to set binding precedents for the 
application of section 408 and the new safety standard to other 
tolerances and exemptions.
    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) 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) 
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. . . .''
    Section 18 of the Federal Insecticide, Fungicide, and Rodenticide 
Act (FIFRA) authorizes EPA to exempt any Federal or State agency from 
any provision of FIFRA, if EPA determines that ``emergency conditions 
exist which require such exemption.'' This provision was not amended by 
Food Quality Protection Act (FQPA). EPA has established regulations 
governing such emergency exemptions in 40 CFR part 166.

III. Emergency Exemption for Diflubenzuron on Pears and FFDCA 
Tolerances

    The Oregon and Washington Departments of Agriculture requested use 
of diflubenzuron on pears, for control of pear psylla, which had 
developed resistance to currently available pesticides, and was 
expected to cause significant economic loss if not adequately 
controlled. EPA has authorized under FIFRA section 18 the use of 
diflubenzuron on pears for

[[Page 52452]]

control of pear psylla in Oregon and Washington. After having reviewed 
the submission, EPA concurs that emergency conditions exist for these 
states.
    As part of its assessment of this emergency exemption, EPA assessed 
the potential risks presented by residues of diflubenzuron in or on 
pears. In doing so, EPA considered the safety standard in FFDCA section 
408(b)(2), and EPA decided that the necessary tolerance under FFDCA 
section 408(l)(6) would be consistent with the safety standard and with 
FIFRA section 18. Consistent with the need to move quickly on the 
emergency exemption in order to address an urgent non-routine situation 
and to ensure that the resulting food is safe and lawful, EPA is 
issuing this tolerance without notice and opportunity for public 
comment as provided in section 408(l)(6). Although this tolerance will 
expire and is revoked on March 31, 2001, under FFDCA section 408(l)(5), 
residues of the pesticide not in excess of the amounts specified in the 
tolerance remaining in or on pears after that date will not be 
unlawful, provided the pesticide is applied in a manner that was lawful 
under FIFRA, and the residues do not exceed a level that was authorized 
by this tolerance at the time of that application. EPA will take action 
to revoke this tolerance earlier if any experience with, scientific 
data on, or other relevant information on this pesticide indicate that 
the residues are not safe.
    Because this tolerance is being approved under emergency conditions 
EPA has not made any decisions about whether diflubenzuron meets EPA's 
registration requirements for use on pears or whether a permanent 
tolerance for this use would be appropriate. Under these circumstances, 
EPA does not believe that this tolerance serves as a basis for 
registration of diflubenzuron by a State for special local needs under 
FIFRA section 24(c). Nor does this tolerance serve as the basis for any 
State other than Oregon and Washington to use this pesticide on this 
crop under section 18 of FIFRA without following all provisions of 
EPA's regulations implementing section 18 as identified in 40 CFR part 
166. For additional information regarding the emergency exemption for 
diflubenzuron, contact the Agency's Registration Division at the 
address provided under the ``ADDRESSES'' section.

IV. Aggregate Risk Assessment and Determination of Safety

    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 and a complete description of 
the risk assessment process, see the final rule on Bifenthrin Pesticide 
Tolerances (62 FR 62961, November 26, 1997) (FRL-5754-7) .
    Consistent with section 408(b)(2)(D), 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 
diflubenzuron and to make a determination on aggregate exposure, 
consistent with section 408(b)(2), for a time-limited tolerance for 
residues of diflubenzuron and its metabolites PCA and CPU, expressed as 
parent compound on pears at 0.5 ppm. EPA's assessment of the dietary 
exposures and risks associated with establishing the tolerance follows.

A. Toxicological Profile

    EPA has 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 risk. EPA has also considered 
available information concerning the variability of the sensitivities 
of major identifiable subgroups of consumers, including infants and 
children. The nature of the toxic effects caused by diflubenzuron are 
discussed in this unit.

B. Toxicological Endpoint

    1. Acute toxicity. A risk assessment for acute (1-day) dietary 
exposure is not necessary. One day single dose oral studies in rats and 
mice indicated only marginal effects on methemoglobin levels at a dose 
level of 10,000 milligrams/kilogram/day (mg/kg/day).
    2. Short- and intermediate-term toxicity. The toxicological 
endpoint for short-term occupational or residential exposure (1-7 days) 
is sulfhemoglobinemia observed in the 14-day subchronic oral study in 
mice dosed with technical grade diflubenzuron. The no observed adverse 
effect level (NOAEL) in this study was 40 mg/kg/day, and the lowest 
observed adverse effect level (LOAEL) was 200 mg/kg/day.
    The toxicological endpoint for intermediate-term occupational or 
residential exposure (1 week to several months) is methemoglobinemia 
observed in the 13-week subchronic feeding study in dogs. For the 
purpose of risk assessments, the NOAEL of 1.64 mg/kg/day in this study 
should be rounded up to 2 mg/kg/day, so as to be consistent with the 
NOAEL of 2 mg/kg/day in the chronic study used to calculate the 
Reference Dose (RfD). The LOAEL in this study was 6.24 mg/kg/day. Since 
an oral NOAEL was selected for a dermal endpoint, a dermal absorption 
factor of 0.5% should be used for this risk assessment when converting 
dermal exposure to oral equivalents. Therefore, the dermal equivalent 
dose producing a NOAEL by the oral route is calculated to be 400 mg/kg/
day (2.0 mg/kg/day divided by 0.005 = 400 mg/kg/day).
    3. Chronic toxicity. EPA has established the RfD for diflubenzuron 
at 0.02 mg/kg/day, based on the NOAEL of 2.0 mg/kg/day from the 52- 
week chronic oral study in dogs. Increases in methemoglobin and 
sulfhemoglobin were observed at the next higher dose level (LOAEL) of 
10.0 mg/kg/day. An uncertainty factor of 100 was applied to account for 
the interspecies extrapolation and intraspecies variability. 
Diflubenzuron has been reviewed by the FAO/WHO joint committee on 
pesticide residues and an Acceptable Daily Intake (ADI) of 0.02 mg/kg/
day was established in 1985. The ADI was based upon the 1- year oral 
toxicity study in dogs with a NOAEL of 2.0 mg/kg/day, with a safety 
factor of 100 applied to account for inter- and intra- species 
variability.
    4. Carcinogenicity. Based on the available evidence, which included 
adequate carcinogenicity studies in rats and mice, and a battery of 
negative mutagenicity studies, diflubenzuron per se has been classified 
as Group E (evidence of non- carcinogenicity for humans). However, p-
chloroaniline (PCA), a metabolite of diflubenzuron, was classified as a 
Group B2 carcinogen (probable human carcinogen). The classification for 
PCA was based on the results of a National Toxicology Program (N.T.P.) 
study reported in July 1989, in which PCA-HCL was administered by 
gavage to rats and mice for 2 years. In rats, clearly increased 
incidences of uncommon sarcomas (fibrosarcomas, hemangiosarcomas, and/
or osteosarcomas) of the spleen were observed in males. In females, two 
additional sarcomas of the spleen were also found. Pheochromocytomas of 
the adrenal gland may also have been associated with the test material 
in male and female rats. In mice, increased incidences of 
hepatocellular neoplasms in the liver and of hemangiosarcomas in the 
spleen and/or liver were observed in males. In females, no evidence of 
carcinogenic activity was observed. The results of several mutagenicity 
studies on PCA were also included in the same N.T.P. Report. PCA was 
mutagenic in Salmonella strains TA98 and TA100 with metabolic 
activation. Gene

[[Page 52453]]

mutations were induced by PCA in cultured mouse lymphoma cells with and 
without metabolic activation. In cultured Chinese Hamster Ovary (CHO) 
cells, treatment with PCA produced significant increases in sister 
chromatic exchanges (SCEs) with and without metabolic activation. 
Chromosomal aberrations were also significantly increased in CHO cells 
in the presence of metabolic activation.
    For the purpose of calculating dietary risk assessments, the 
following procedure was used:
    i. P-chlorophenylurea (CPU) and p-chloroacetanilide (PCAA), 
additional metabolites of diflubenzuron that are closely related to PCA 
and for which there are no adequate carcinogenicity data available, 
should be considered to be potentially carcinogenic and to have the 
same carcinogenic potency (Q1*) as PCA.
    ii. The sum of PCA, CPU, and PCAA residues in ingested food should 
be used to estimate the dietary exposure of humans to the carcinogenic 
metabolites of diflubenzuron.
    iii. In addition to ingested residues of these three metabolites, 
amounts of PCA, CPU, and/or PCAA formed in vivo following ingestion of 
diflubenzuron should also be included when estimating the total 
exposure of humans to the carcinogenic metabolites of diflubenzuron. 
The in vivo conversion of ingested diflubenzuron to PCA and/or CPU was 
estimated to be 2.0%, based on data in the rat metabolism study.
    The Q1* (estimated unit risk) for PCA, based upon spleen 
sarcoma rates in male rats, was calculated to be 6.38 x 10-2 
(mg/kg/day)-1 in human equivalents. It has been determined 
that PCAA does not occur in animal or plant tissues in significant 
amounts.

C. Exposures and Risks

    1. From food and feed uses. Tolerances have been established (40 
CFR 180.377) for the residues of diflubenzuron per se, in or on citrus, 
artichokes, walnuts, mushrooms, cottonseed, soybean, rice, and 
associated livestock commodities. Existing tolerances range from 0.05 
ppm in/on soybeans, to 6.0 ppm in/on artichokes. Tolerances of 0.05 ppm 
have also been established for residues of diflubenzuron in animal 
commodities. Risk assessments were conducted by EPA to assess dietary 
exposures and risks from diflubenzuron as follows:
    i. Acute exposure and risk. 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. One day single dose oral studies in rats 
and mice indicated only marginal effects on methemoglobin levels at a 
dose level of 10,000 mg/kg/day. Therefore, this risk assessment is not 
needed, as there are no significant acute effects observed.
    ii. Chronic exposure and risk. For conducting the chronic dietary 
risk assessment, refined residue estimates were used for all 
commodities except for pears. Percent of crop treated figures were also 
used for certain commodities. The percent of RfD utilized for Non-
Nursing Infants <1 Yr. Old (the most highly exposed subgroup) was 6.1%. 
For Nursing Infants, this figure was 2.2%, and for all other population 
subgroups, including the overall U.S. Population, the ARC utilized less 
than 1% of the RfD.
    Section 408(b)(2)(E) authorizes EPA to use available data and 
information on the anticipated residue levels of pesticide residues in 
food and the actual levels of pesticide chemicals that have been 
measured in food. If EPA relies on such information, EPA must require 
that data be provided 5 years after the tolerance is established, 
modified, or left in effect, demonstrating that the levels in food are 
not above the levels anticipated. Following the initial data 
submission, EPA is authorized to require similar data on a time frame 
it deems appropriate. As required by section 408(b)(2)(E), EPA will 
issue a data call-in for information relating to anticipated residues 
to be submitted no later than 5 years from the date of issuance of this 
tolerance.
    Section 408(b)(2)(F) states that the Agency may use data on the 
actual percent of crop treated (PCT) for assessing chronic dietary risk 
only if the Agency can make the following findings: That the data used 
are reliable and provide a valid basis to show what percentage of the 
food derived from such crop is likely to contain such pesticide 
residue; that the exposure estimate does not underestimate exposure for 
any significant subpopulation group; and if data are available on 
pesticide use and food consumption in a particular area, the exposure 
estimate does not understate exposure for the population in such area. 
In addition, the Agency must provide for periodic evaluation of any 
estimates used. To provide for the periodic evaluation of the estimate 
of PCT as required by section 408(b)(2)(F), EPA may require registrants 
to submit data on PCT.
    The Agency used PCT information as follows: 1% for grass/rangeland; 
3% for cottonseed; 8% for grapefruit; 3.1% for mushrooms; 2% for 
oranges; 4% for tangerines; 1% for soybean; and 5% for cattle bolus. 
Other commodities were assumed to be 100% treated.
    The Agency believes that the three conditions, discussed in section 
408 (b)(2)(F) in this unit concerning the Agency's responsibilities in 
assessing chronic dietary risk findings, have been met. The PCT 
estimates are derived from Federal and private market survey data, 
which are reliable and have a valid basis. Typically, a range of 
estimates are supplied and the upper end of this range is assumed for 
the exposure assessment. By using this upper end estimate of the PCT, 
the Agency is reasonably certain that the percentage of the food 
treated is not likely to be underestimated. The regional consumption 
information and consumption information for significant subpopulations 
is taken into account through EPA's computer-based model for evaluating 
the exposure of significant subpopulations including several regional 
groups. Use of this consumption information in EPA's risk assessment 
process ensures that EPA's exposure estimate does not understate 
exposure for any significant subpopulation group and allows the Agency 
to be reasonably certain that no regional population is exposed to 
residue levels higher than those estimated by the Agency. Other than 
the data available through national food consumption surveys, EPA does 
not have available information on the regional consumption of food to 
which diflubenzuron may be applied in a particular area.
    2. From drinking water. The Agency currently lacks sufficient 
water- related exposure data to complete a comprehensive drinking water 
exposure analysis and risk assessment for diflubenzuron. Because the 
Agency does not have comprehensive and reliable monitoring data, 
drinking water concentration estimates must be made by reliance on some 
sort of simulation or modeling. To date, there are no validated 
modeling approaches for reliably predicting pesticide levels in 
drinking water. The Agency is currently relying on the models GENEEC 
and PRZM/EXAMS for surface water, which are used to produce estimates 
of pesticide concentrations in a farm pond; and SCI-GROW, which 
predicts pesticide concentrations in groundwater. None of these models 
include consideration of the impact that processing of raw water, for 
distribution as drinking water, would likely have on the removal of 
pesticides from the source water. The primary use of these models by 
the Agency at this stage is to provide a coarse screen for sorting out 
pesticides for which it is highly unlikely

[[Page 52454]]

that drinking water concentrations would ever exceed human health 
levels of concern.
    In the absence of monitoring data for pesticides, drinking water 
levels of comparison (DWLOCs) are calculated and used as a point of 
comparison against the model estimates of a pesticide's concentration 
in water. DWLOCs are theoretical upper limits for a pesticide's 
concentration in drinking water in light of total aggregate exposure to 
a pesticide in food, drinking water, and residential uses. A DWLOC will 
vary depending on the toxic endpoint, with drinking water consumption, 
and body weights. Different populations will have different DWLOCs. 
DWLOCs are used in the risk assessment process as a surrogate measure 
of potential exposure associated with pesticide exposure through 
drinking water. DWLOC values are not regulatory standards for drinking 
water. Since DWLOCs address total aggregate exposure to diflubenzuron 
they are further discussed in the aggregate risk sections below.
    3. From non-dietary exposure. Diflubenzuron is a restricted use 
pesticide and therefore not available for use by homeowners, although 
it is possible that non- agricultural uses of diflubenzuron may expose 
people in residential locations. However, based on the low dermal 
absorption rate (0.5%), and the extremely low dermal and inhalation 
toxicity, these uses are expected to result in insignificant risks.
    4. Cumulative exposure to substances with common mechanism of 
toxicity. Section 408(b)(2)(D)(v) 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.''
    Diflubenzuron is structurally similar to other substituted 
benzoylurea insecticides including triflumuron and flucycloxuron. 
However, EPA does not have, at this time, available data to determine 
whether diflubenzuron has a common mechanism of toxicity with other 
substances or how to include this pesticide in a cumulative risk 
assessment. Unlike other pesticides for which EPA has followed a 
cumulative risk approach based on a common mechanism of toxicity, 
diflubenzuron does not appear to produce a toxic metabolite produced by 
other substances. For the purposes of this tolerance action, therefore, 
EPA has not assumed that diflubenzuron has a common mechanism of 
toxicity with other substances. For more 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 final rule for Bifenthrin Pesticide Tolerances (62 FR 62961, 
November 26, 1997).

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

    1. Acute risk. Since one day single dose oral studies in rats and 
mice indicated only marginal effects, this risk assessment is not 
needed, as there were no significant acute effects observed.
    2. Chronic risk. Using the ARC exposure assumptions described in 
this unit, EPA has concluded that aggregate exposure to diflubenzuron 
from food will utilize <1 of the RfD for the U.S. population. The major 
identifiable subgroup with the highest aggregate exposure is Non-
nursing infants, <1 year old, for which 6.1% of the RfD was utilized. 
EPA generally has no concern for exposures below 100% of the RfD 
because the RfD represents the level at or below which daily aggregate 
dietary exposure over a lifetime will not pose appreciable risks to 
human health. The Agency does not have monitoring data available to 
perform a quantitative drinking water risk assessment for diflubenzuron 
at this time. Based on PRZM/EXAMS modeling, the average annual mean 
concentration of diflubenzuron in surface water sources is not expected 
to exceed 0.05 ppb. Estimated concentrations of CPU in surface water 
sources is not expected to exceed 0.73 ppb. These values reflect the 
maximum concentrations for any of the crops treated with diflubenzuron 
(including pears). The DWLOCs for chronic (non-cancer) exposure to 
diflubenzuron in drinking water for the U.S. population and Non Nursing 
Infants (< 1 yr. old), and Females (13+ yrs. old/nursing) are 700, 190, 
and 600 ppb, respectively. The estimated maximum concentration of 
diflubenzuron in surface and ground water (0.05 ppb) is lower than the 
DWLOCs as a contribution to chronic aggregate exposure. Therefore, EPA 
concludes that residues of diflubenzuron and its metabolites in 
drinking water would not result in an unacceptable estimate of chronic, 
non- cancer risk. Despite the potential for exposure to diflubenzuron 
in drinking water and from non-dietary, non-occupational exposure, EPA 
does not expect the aggregate exposure to exceed 100% of the RfD.
    3. Short- and intermediate-term risk. Short- and intermediate-term 
aggregate exposure takes into account chronic dietary food and water 
(considered to be a background exposure level) plus indoor and outdoor 
residential exposure.
    As stated earlier, although residential exposure has been 
considered possible from, for example, area-wide gypsy moth or mosquito 
control, this contribution is anticipated to be negligible. Thus, it 
was determined that this risk assessment is not necessary.
    4. Aggregate cancer risk for U.S. population. A cancer risk 
assessment was conducted for the metabolites of diflubenzuron, PCA and 
CPU. As a conservative measure, EPA assumes that PCA/CPU occupied 2% of 
diflubenzuron tolerance levels, based upon metabolism studies. Based 
upon the ARC estimates described above, the cancer risk for the overall 
U.S. population from dietary (food only) was calculated to be 5 x 
10-7, which does not exceed EPA's levels of concern. The 
DWLOC for cancer risk for the U.S. population is 0.26 ppb. Estimated 
drinking water concentrations from PCA/CPU (0.73 ppb) are greater than 
the DWLOC of 0.26, for cancer risk. However, EPA believes these 
estimates are significantly overstated for several reasons. The PRZM/
EXAMS model used to derive these estimates was designed for ecological 
risk assessments, and uses a scenario of a body of water approximating 
the size of a 2.5 acre pond. This tends to overstate chronic drinking 
water exposure levels for the following reasons. First, surface water 
source drinking water generally comes from bodies of water that are 
substantially larger. Second, the scenario assumes that the whole basin 
receives an application of the pesticide, but in virtually all cases, 
basins used for drinking water will contain a substantial portion of 
the area that does not receive pesticide application. Third, there is 
often at least some flow or turnover of the water, so the persistence 
of the pesticide near the drinking water facility is usually 
overestimated. Fourth, even assuming that the reservoir is directly 
adjacent to an agricultural field, the field may not be used to grow a 
crop on which the pesticide in question is registered for use. Fifth, 
the PRZM/EXAMS scenario does not take into account reductions in 
residue-loading due to applications less than the maximum application 
rate or no treatment of the crop at all. Considering these 
uncertainties associated with the modeled water estimates noted above, 
and the fact that the estimated concentrations are within close range 
of the DWLOCs, EPA concludes with reasonable certainty that residues of 
diflubenzuron in drinking water will

[[Page 52455]]

not contribute significantly to the aggregate cancer human health risk.
    5. Determination of safety. Based on these risk assessments, EPA 
concludes that there is a reasonable certainty that no harm will result 
from aggregate exposure to diflubenzuron residues.

E. Aggregate Risks and Determination of Safety for Infants and Children

    1. Safety factor for infants and children-- i. In general. In 
assessing the potential for additional sensitivity of infants and 
children to residues of diflubenzuron, EPA considered data from 
developmental toxicity studies in the rat and rabbit and a 2-generation 
reproduction study in the rat. The developmental toxicity studies are 
designed to evaluate adverse effects on the developing organism 
resulting from maternal pesticide exposure during gestation. 
Reproduction studies provide information relating to effects from 
exposure to the pesticide on the reproductive capability of mating 
animals and data on systemic toxicity.
    FFDCA section 408 provides that EPA shall apply an additional 
tenfold margin of safety for infants and children in the case of 
threshold effects to account for pre- and post-natal toxicity and the 
completeness of the data base unless EPA determines that a different 
margin of safety will be safe for infants and children. Margins of 
safety are incorporated into EPA risk assessments either directly 
through use of a margin of exposure (MOE) analysis or through using 
uncertainty (safety) factors in calculating a dose level that poses no 
appreciable risk to humans. EPA believes that reliable data support 
using the standard MOE and uncertainty factor (usually 100 for combined 
inter- and intra-species variability) and not the additional tenfold 
MOE/uncertainty factor when EPA has a complete data base under existing 
guidelines and when the severity of the effect in infants or children 
or the potency or unusual toxic properties of a compound do not raise 
concerns regarding the adequacy of the standard MOE/safety factor.
    ii. Developmental toxicity studies. In the developmental study in 
rats, the maternal (systemic) and the developmental (fetal) NOAEL were 
both 1,000 mg/kg/day. No LOAELs were achieved, as no maternal or 
developmental toxicity was observed.
    In the developmental toxicity study in rabbits, both the maternal 
(systemic) and the developmental (fetal) NOAELs were both 1,000 mg/kg/
day. As with the rat study, mentioned above, no LOAELs were achieved, 
as no maternal or developmental toxicity was observed.
    iii. Reproductive toxicity study. In the 2-generation reproductive 
toxicity study in rats, the parental (systemic) NOAEL was considered to 
be less than 36 mg/kg/day for males, and less than 42 mg/kg/day for 
females based on hematological effects at all dose levels tested. For 
offspring effects, the NOAEL was equal to 427 mg/kg/day, and the LOAEL 
was equal to 4,254 mg/kg/day, based on statistically significant 
decreases in F-1 pup weight on days 4, 8, and 21 of lactation.
    iv. Pre- and post-natal sensitivity. The toxicological database for 
evaluating pre- and post-natal toxicity for diflubenzuron is completed 
with respect to current data requirements. There are no pre- or post-
natal toxicity concerns for infants and children, based upon the result 
of the developmental and reproductive studies mentioned above.
    v. Conclusion. The OPP FQPA Safety Factor Committee recommended 
that the 10X factor for increased susceptibility of infants and 
children be reduced to 1X, for diflubenzuron. This decision was based 
on the determination that there was no indication of increased 
susceptibility of rats or rabbits to in utero and/or postnatal exposure 
to diflubenzuron, and because exposure assessments do not indicate a 
concern for potential risk to infants and children. There is a complete 
toxicity database for diflubenzuron and exposure data is complete or is 
estimated based on data that reasonably accounts for potential 
exposures.
    2. Acute risk. Since one day single dose oral studies in rats and 
mice indicated only marginal effects, this risk assessment is not 
needed, as there are no significant acute effects observed.
    3. Chronic risk. Using the exposure assumptions described in this 
unit, EPA has concluded that aggregate exposure to diflubenzuron from 
food will utilize 6.1% of the RfD for Non-Nursing Infants < 1 year old, 
the most highly exposed infant/children population subgroup. EPA 
generally has no concern for exposures below 100% of the RfD because 
the RfD represents the level at or below which daily aggregate dietary 
exposure over a lifetime will not pose appreciable risks to human 
health. Despite the potential for exposure to diflubenzuron in drinking 
water and from non-dietary, non-occupational exposure, EPA does not 
expect the aggregate exposure to exceed 100% of the RfD.
    4. Short- or intermediate-term risk. As stated earlier, although 
residential exposure has been considered possible from, for example, 
area-wide gypsy moth or mosquito control, this contribution is 
anticipated to be negligible. Thus, it was determined that this risk 
assessment is not necessary.
    5. Determination of safety. Based on these risk assessments, EPA 
concludes that there is a reasonable certainty that no harm will result 
to infants and children from aggregate exposure to diflubenzuron 
residues.

V. Other Considerations

A. Metabolism in Plants and Animals

    The nature of the residue in plants and animals is adequately 
understood. The residue of concern is diflubenzuron and its metabolites 
p-chloroaniline (PCA) and p- chlorophenylurea (CPU), expressed as the 
parent compound.

B. Analytical Enforcement Methodology

    Adequate methodology for the analysis of diflubenzuron is available 
to enforce the tolerance expression. Three analytical methods for 
diflubenzuron are published in PAM, Vol. II as Methods I, II, and III. 
All three methods have undergone successful Agency validations and are 
acceptable for enforcement purposes.

C. Magnitude of Residues

    Residues of diflubenzuron and its metabolites are not expected to 
exceed 0.5 ppm in/on pears as a result of this use.

D. International Residue Limits

    There is a Codex maximum residue limit (MRL) for pears at 1 mg/kg, 
a MRL for Mexico at 1.0 mg/kg, and no limits set for Canada for pears. 
This tolerance is to be set at a lower level than the MRLs. This is a 
time-limited tolerance, established solely in support of this section 
18 use. In considering permanent tolerances for pears in the future, 
the Agency will take these circumstances into account.

E. Rotational Crop Restrictions

    Available data for diflubenzuron indicate that tolerances for 
residues in rotational crops will not be required, provided the label 
specifies a restriction for the planting of rotational crops of at 
least 30 days.

VI. Conclusion

    Therefore, the tolerance is established for combined residues of 
diflubenzuron and its metabolites PCA and CPU, expressed as parent 
compound in pears at 0.5 ppm.

VII. Objections and Hearing Requests

    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

[[Page 52456]]

hearing on those objections. The EPA procedural regulations which 
govern the submission of objections and requests for hearings appear in 
40 CFR part 178. Although the procedures in those regulations require 
some modification to reflect the amendments made to the FFDCA by the 
FQPA of 1996, EPA will continue to use those procedures, with 
appropriate adjustments, until the necessary modifications can be made. 
The new section 408(g) provides essentially the same process for 
persons to ``object'' to a regulation for an exemption from the 
requirement of a tolerance issued by EPA under new section 408(d), as 
was provided in the old FFDCA sections 408 and 409. However, the period 
for filing objections is now 60 days, rather than 30 days.

A. What Do I Need to Do to File an Objection or Request a Hearing?

    You must file your objection or request a hearing on this 
regulation in accordance with the instructions provided in this unit 
and in 40 CFR part 178. To ensure proper receipt by EPA, you must 
identify docket control number OPP-300921 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 November 
29, 1999.
    1. Filing the request. Your objection must specify the specific 
provisions in the regulation that you object to, and the grounds for 
the objections (40 CFR 178.25). If a hearing is requested, the 
objections must include a statement of the factual issues(s) on which a 
hearing is requested, the requestor's contentions on such issues, and a 
summary of any evidence relied upon by the objector (40 CFR 178.27). 
Information submitted in connection with an objection or hearing 
request may be claimed confidential 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. A copy of the 
information that does not contain CBI must be submitted for inclusion 
in the public record. Information not marked confidential may be 
disclosed publicly by EPA without prior notice.
    Mail your written request to: Office of the Hearing Clerk (1900), 
Environmental Protection Agency, 401 M St., SW., Washington, DC 20460. 
You may also deliver your request to the Office of the Hearing Clerk in 
Room M3708, Waterside Mall, 401 M St., SW., Washington, DC 20460. The 
Office of the Hearing Clerk is open from 8 a.m. to 4 p.m., Monday 
through Friday, excluding legal holidays. The telephone number for the 
Office of the Hearing Clerk is (202) 260-4865.
    2. Tolerance fee payment. If you file an objection or request a 
hearing, you must also pay the fee prescribed by 40 CFR 180.33(i) or 
request a waiver of that fee pursuant to 40 CFR 180.33(m). You must 
mail the fee to: EPA Headquarters Accounting Operations Branch, Office 
of Pesticide Programs, P.O. Box 360277M, Pittsburgh, PA 15251. Please 
identify the fee submission be labeling it ``Tolerance Petition Fees.''
    EPA is authorized to waive any fee requirement ``when in the 
judgement of the Administrator such a waiver or refund is equitable and 
not contrary to the purpose of this subsection.'' (cite). For 
additional information regarding the waiver of these fees, you may 
contact James Tompkins by phone at (703) 305-5697, by e-mail at 
[email protected], or by mailing a request for information to Mr. 
Tompkins at Registration Division (7505C), Office of Pesticide 
Programs, Environmental Protection Agency, 401 M St., SW., Washington, 
DC 20460.
    If you would like to request a waiver of the tolerance objection 
fees, you must mail your request for such a waiver to: James Hollins, 
Information Resources and Services Division (7502C), Office of 
Pesticide Programs, Environmental Protection Agency, 401 M St., SW., 
Washington, DC 20460.
    3.  Copies for the Docket. In addition to filing an objection or 
hearing request with the Hearing Clerk as described in Unit VII.A. of 
this preamble, you should also send a copy of your request to the PIRIB 
for its inclusion in the official record that is described in Unit 
I.B.2. of this preamble. Mail your copies, identified by the docket 
number OPP-300921, to: Public Information and Records Integrity Branch, 
Information Resources and Services Division (7502C), Office of 
Pesticide Programs, Environmental Protection Agency, 401 M St., SW., 
Washington, DC 20460. In person or by courier, bring a copy to the 
location of the PIRIB described in Unit I.B.2. of this preamble. You 
may also send an electronic copy of your request via e-mail to: opp-
[email protected]. Please use an ASCII file format and avoid the use of 
special characters and any form of encryption. Copies of electronic 
objections and hearing requests will also be accepted on disks in 
WordPerfect 5.1/6.1 file format or ASCII file format. Do not include 
any CBI in your electronic copy. You may also submit an electronic copy 
of your request at many Federal Depository Libraries.

B. When Will the Agency Grant a Request for a Hearing?

    A request for a hearing will be granted if the Administrator 
determines that the material submitted shows the following: There is a 
genuine and substantial issue of fact; there is a reasonable 
possibility that available evidence identified by the requestor would, 
if established resolve one or more of such issues in favor of the 
requestor, taking into account uncontested claims or facts to the 
contrary; and resolution of the factual issues(s) in the manner sought 
by the requestor would be adequate to justify the action requested (40 
CFR 178.32).

VIII. Regulatory Assessment Requirements

    This final rule establishes a tolerance under section 408 of the 
FFDCA. 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). 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 prior consultation with 
State, local, and tribal government officials as specified by Executive 
Order 12875, entitled Enhancing the Intergovernmental Partnership (58 
FR 58093, October 28, 1993) and Executive Order 13084, entitled  
Consultation and Coordination with Indian Tribal Governments (63 FR 
27655, May 19,1998), or special consideration of environmental justice 
related issues 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 require OMB review in 
accordance with Executive Order 13045, entitled Protection of Children 
from Environmental Health Risks and Safety Risks (62 FR 19885, April 
23, 1997). 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 12612, entitled Federalism (52 FR 41685, October 30, 
1987). This action directly regulates growers, food processors, food 
handlers and food retailers, not States. This

[[Page 52457]]

action does not alter the relationships or distribution of power and 
responsibilities established by Congress in the preemption provisions 
of the FFDCA, 21 U.S.C. 346a(n)(4). 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). In addition, since 
tolerances and exemptions that are established under FFDCA section 
408(l)(6), such as the tolerance 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.

IX. Submission to Congress and the Comptroller General

    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 rule in the Federal Register. This 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: September 14, 1999 .

Peter Caulkins,

Acting Director, Registration Division, Office of Pesticide Programs.
    Therefore, 40 CFR chapter I is amended as follows:

PART 180--[AMENDED]

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

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

    2. In Sec. 180.377, by adding text to paragraph (b) to read as 
follows:


Sec. 180.377  Diflubenzuron; tolerances for residues.

* * * * *
    (b) Section 18 emergency exemptions. Time-limited tolerances are 
established for residues of diflubenzuron and its metabolites, PCA (4-
chloroaniline) and CPU (4-chlorophenylurea), expressed as the parent 
diflubenzuron, in connection with use of this pesticide under a section 
18 emergency exemption granted by EPA. The tolerances will expire on 
the dates specified in the following table.

 
------------------------------------------------------------------------
                                                          Expiration/
            Commodity              Parts per million    revocation date
------------------------------------------------------------------------
Pears...........................  0.5                 3/31/00
------------------------------------------------------------------------

* * * * *

[FR Doc. 99-25312 Filed 9-28-99; 8:45 am]
BILLING CODE 6560-50-F