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Difenoconazole - Pesticide Tolerances for Emergency Exemptions 8/99

[Federal Register: September 1, 1999 (Volume 64, Number 169)]
[Rules and Regulations]
[Page 47680-47687]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr01se99-20]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 180

[OPP-300904; FRL-6094-3]
RIN 2070-AB78

Difenoconazole; Pesticide Tolerances for Emergency Exemptions

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: This regulation establishes time-limited tolerances for
residues of difenoconazole [[(2S,4R)/(2R,4S)/(2R,4R)/(2S,4S)]1-[2-[4-
(4-chlorophenoxy)-2-chlorophenyl]-4-methyl-1,3-dioxolan-2-yl-methyl]-
1H-1,2,4-triazole] in or on sweet corn commodities. 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 sweet corn seed. This regulation establishes a
maximum permissible level for residues of difenoconazole in these food
and feed commodities pursuant to section 408(l)(6) of the Federal Food,
Drug, and Cosmetic Act, as amended by the Food Quality Protection Act
of 1996. The tolerances will expire and are revoked on January 31,
2001.

DATES: This regulation is effective September 1, 1999. Objections and
requests for hearings must be received by EPA on or before November 1,
1999.

ADDRESSES: Written objections and hearing requests, identified by the
docket control number [OPP-300904], must be submitted to: Hearing Clerk
(1900), Environmental Protection Agency, Rm. M3708, 401 M St., SW.,
Washington, DC 20460. Fees accompanying objections and hearing requests
shall be labeled "Tolerance Petition Fees" and forwarded to: EPA
Headquarters Accounting Operations Branch, OPP (Tolerance Fees), P.O.
Box 360277M, Pittsburgh, PA 15251. A copy of any objections and hearing
requests filed with the Hearing Clerk identified by the docket control
number, [OPP-300904], must also be submitted 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, bring a copy of
objections and hearing requests to Rm. 119, Crystal Mall 2 (CM #2),
1921 Jefferson Davis Hwy., Arlington, VA.
    A copy of objections and hearing requests filed with the Hearing
Clerk may also be submitted electronically by sending electronic mail
(e-mail) to: opp-docket@epa.gov. Copies of electronic objections and
hearing requests must be submitted as an ASCII file avoiding the use of
special characters and any form of encryption. Copies of objections and
hearing requests will also be accepted on disks in WordPerfect 5.1/6.1
or ASCII file format. All copies of electronic objections and hearing
requests must be identified by the docket control number [OPP-300904].
No Confidential Business Information (CBI) should be submitted through
e-mail. Copies of electronic objections and hearing requests on this
rule may be filed online at many Federal Depository Libraries.

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. Office
location, telephone number, and e-mail address: Rm. 271, CM #2, 1921
Jefferson Davis Hwy., Arlington, VA, (703) 308-9356,
beard.andrea@epa.gov.

SUPPLEMENTARY INFORMATION: EPA, on its own initiative, pursuant to
section 408(l)(6) of the Federal Food, Drug, and Cosmetic Act (FFDCA),
21 U.S.C. 346a, is establishing tolerances for residues of the
fungicide difenoconazole, in or on sweet corn seed, forage, and stover
at 0.1 part per million (ppm). These tolerances will expire and are
revoked on January 31, 2001. EPA will publish a document in the Federal
Register to remove the revoked tolerances from the Code of Federal
Regulations.

I. Background and Statutory Findings

    The Food Quality Protection Act of 1996 (FQPA) (Public Law 104-170)
was signed into law August 3, 1996. FQPA amends both the FFDCA, 21
U.S.C. 301 et seq., and the Federal Insecticide, Fungicide, and
Rodenticide Act (FIFRA), 7 U.S.C. 136 et seq. The FQPA amendments went
into effect immediately. Among other things, FQPA amends FFDCA to bring
all EPA pesticide tolerance-setting activities under a new section 408
with a new safety standard and new procedures. These activities are
described in this preamble and discussed in greater detail in the final
rule establishing the time-limited tolerance associated with the
emergency exemption for use of propiconazole on sorghum (61 FR 58135,
November 13, 1996) (FRL-5572-9).

[[Page 47681]]

    New 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 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 FQPA. EPA has established regulations governing such
emergency exemptions in 40 CFR part 166.
    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.
    Because decisions on section 18-related tolerances must proceed
before EPA reaches closure on several policy issues relating to
interpretation and implementation of the FQPA, EPA does not intend for
its actions on such tolerances to set binding precedents for the
application of section 408 and the new safety standard to other
tolerances and exemptions.

II. Emergency Exemption for Difenoconazole on Sweet Corn Seed and
FFDCA Tolerances

    Idaho leads the nation in production of SH2 hybrid sweet corn seed,
accounting for more than 90% of the total U.S. production. SH2 hybrids
are used in the production of super sweet varieties of fresh market and
processing sweet corn. In the past, captafol was used in combination
with other registered fungicides as a sweet corn seed protectant.
However, all captafol uses were voluntarily canceled in May of 1987 as
a result of the captafol Special Review. According to the Applicant,
the currently registered fungicides available for use on sweet corn
provide only marginal control of dieback syndrome (brought on by fungal
pathogens, Penicillium, Pythium, and Fusarium species) on hybrid sweet
corn varieties. If difenoconazole is not available for use, stand
reductions of 20-60% could occur, resulting in significant economic
losses for Idaho's sweet corn seed producers, and sweet corn growers in
other States, such as Florida where the disease problem is particularly
severe. Prior to this year, Idaho received exemptions for use of
another material, imazalil, for this situation; however, issues
surfaced last year concerning imazalil and EPA could not make the
safety finding as required under FQPA for the imazalil use. EPA has
authorized under FIFRA section 18 the use of difenoconazole on sweet
corn seed for control of fungal pathogens in Idaho. After having
reviewed the submission, EPA concurs that emergency conditions exist
for this State.
    As part of its assessment of this emergency exemption, EPA assessed
the potential risks presented by residues of difenoconazole in or on
sweet corn commodities. In doing so, EPA considered the safety standard
in FFDCA section 408(b)(2), and EPA decided that the necessary
tolerances 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 these tolerances without notice and opportunity
for public comment under section 408(e), as provided in section
408(l)(6). Although these tolerances will expire and are revoked on
January 31, 2001, under FFDCA section 408(l)(5), residues of the
pesticide not in excess of the amounts specified in the tolerances
remaining in or on sweet corn commodities 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 levels that were authorized
by these tolerances at the time of that application. EPA will take
action to revoke these tolerances earlier if any experience with,
scientific data on, or other relevant information on this pesticide
indicate that the residues are not safe.
    Because these tolerances are being approved under emergency
conditions, EPA has not made any decisions about whether difenoconazole
meets EPA's registration requirements for use on sweet corn seed or
whether permanent tolerances for this use would be appropriate. Under
these circumstances, EPA does not believe that these tolerances serve
as basis for registration of difenoconazole by a State for special
local needs under FIFRA section 24(c). Nor do these tolerances serve as
the basis for any State other than Idaho 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
difenoconazole, contact the Agency's Registration Division at the
address provided under the "ADDRESSES" section.

III. 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
difenoconazole and to make a determination on aggregate exposure,
consistent with section 408(b)(2), for a time-limited tolerance for
residues of difenoconazole on sweet corn seed, stover, and forage at
0.1 ppm. EPA's assessment of the dietary exposures and risks associated
with establishing the tolerances 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 difenoconazole are
discussed in this unit.

B. Toxicological Endpoints

    1. Acute toxicity. Based on the available acute toxicity data, EPA
has determined that the no observable adverse effect level (NOAEL) of
25

[[Page 47682]]

milligrams per kilograms body weight per day (mg/kg/bwt/day) from the
developmental study in rabbits should be used to assess risk from acute
toxicity. Increases in post-implantation loss and resorption, decreases
in fetal body weight, and decreases in body weight gains and food
consumption in dams, were observed at the lowest obsevable adverse
effect level (LOAEL) of 75 mg/kg/day. Using the uncertainty factors
(UFs) of 10x for interspecies and 10x for intraspecies variations, the
acute Reference Dose (RfD) is 0.25 mg/kg/day. The acute risk assessment
will evaluate acute dietary risk to females 13+ years, the population
subgroup of concern.
    2. Short- and intermediate-term toxicity. For short-term Margin of
Exposure (MOE) calculations, the developmental NOAEL of 25 mg/kg/day,
from the developmental rabbit study will be used, with a dermal
absorption factor adjustment of 75%. At the LOAEL of 75 mg/kg/day,
there were increased post-implantation losses and resorptions per dose,
a significant decrease in fetal body weight, and decrease in body
weight gains and food consumption in the dams.
    For intermediate-term MOE calculations, the NOAEL of 1.25 mg/kg/day
from the 2-generation study in rats will be used. At the LOAEL of 12.5
mg/kg/day, there were decreased pup weights.
    3. Chronic toxicity. EPA has established the RfD for difenoconazole
at 0.01 mg/kg/day. This RfD is based on cumulative decreases in body
weight gains at the LOAEL of 24.0 mg/kg/day from the chronic feeding/
oncogenicity study in rats with a NOAEL of 0.96 mg/kg/day, and an
uncertainty factor of 100.
    4. Carcinogenicity. Difenoconazole has been classified as a Group C
possible carcinogen, based on statistically significant increases in
liver adenomas, carcinomas, and combined adenomas and carcinomas in
both sexes of CD-1 mice, only at doses that were considered to be
excessively high for carcinogenicity testing. The MOE approach was
recommended for risk assessments, because there was only very weak
evidence of carcinogenic potential at dose levels not considered to be
excessive, with significant changes seen only at excessive doses.
Additionally, there was no evidence of genotoxicity. However, at this
time, the Agency has not defined the acceptable level of concern for
cancer risk using the MOE approach. Therefore, a quantitative risk
analysis was conducted utilizing the Q1* approach. The
Q1* was calculated to be 1.57 x 10-1 (mg/kg/day)-1.

C. Exposures and Risks

    1. From food and feed uses. Permanent tolerances have been
established (40 CFR 180.475) for the residues of difenoconazole, in or
on wheat and livestock commodities ranging from 0.05 to 0.1 ppm and on
bananas (import) at 0.2 ppm. Risk assessments were conducted by EPA to
assess dietary exposures and risks from difenoconazole 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. EPA's detailed acute analysis estimated
the distribution of single-day exposures for the subgroup Females 13+
Years Old. An evaluation was not conducted for the overall U.S.
population and infant and children subgroups, because oral
toxicological studies did not demonstrate effects on these groups that
could be attributable to a single dose exposure. The Dietary Exposure
Evaluation Model (DEEM) analysis evaluated the individual food
consumption as reported by respondents in the USDA 1989-91 Nationwide
Continuing Surveys for Food Intake by Individuals (CSFII) and
accumulated exposure to the chemical for each commodity. This acute
exposure analysis was performed assuming tolerance level residues and
100% crop treated. Taking into account published and proposed
tolerances (including these for sweet corn commodities), at the 95th
percentile, the exposure utilized less than 1% of the RfD for the
population subgroup of concern, Females 13+ Yrs. Old. Therefore, the
level of concern is not exceeded.
    ii. Chronic exposure and risk. The chronic risk assessment was
conducted using mean consumption (3-day average) values, and was
refined using anticipated residues and percent of crop treated (PCT)
information for select commodities. The RfD of 0.01 mg/kg/day and an
uncertainty factor of 100 were used. Since it was determined that the
FQPA UF of 3x was not necessary, acceptable dietary exposure must not
exceed 100% of the chronic RfD for all population subgroups. The
Novigen DEEM system was used for this chronic dietary exposure
analysis.The subgroups listed below are: (1) the U.S. Population (48
contiguous States); (2) those for infants and children; and, (3) the
other subgroups (adult) for which the percentage of the RfD occupied is
greater than that occupied by the subgroup U.S. Population (48
contiguous States). The results are summarized below.

------------------------------------------------------------------------
                                    Exposure (mg/kg
       Population Subgroup             bwt/day)          % Chronic RfD
------------------------------------------------------------------------
U.S. Population (48 contiguous    0.000005            < 1
 States).
All Infants (< 1 yr)............  0.000016            < 1
Nursing Infants (<1 yr).........  0.000007            < 1
Non-nursing Infants (<1 yr).....  0.000019            < 1
Children (1-6 yrs)..............  0.000011            < 1
Children (7-12 yrs).............  0.000005            < 1
Females (13+ yrs / Nursing).....  0.000006            < 1
Seniors (55+ yrs)...............  0.000006            < 1
Non-Hispanic, Other than Black/   0.000006            < 1
 White.
------------------------------------------------------------------------

    As shown in the above table, chronic dietary risk does not exceed
the level of concern for any of the population subgroups.
    iii. Cancer exposure and risk. The Agency previously classified
difenoconazole as a possible human carcinogen; this chemical would now
be classified as a likely human carcinogen in accordance with the
Agency's "Proposed Guidelines for Carcinogenic Risk Assessment"
(April 10, 1996). As previously explained in this document, a non-
linear, MOE approach was recommended to quantify human cancer risk from
difenoconazole. However, at this time the Agency has not defined the
acceptable level of concern for cancer risk using the MOE approach.
Therefore, the linear Q1* approach was used for calculating
cancer risk. A Q1* of 0.157 (mg/kg/day)-1 was
determined based on the male mouse liver adenoma and/or carcinoma
combined tumor rates in the 78-week cancer study in mice. The exposure
analysis estimating potential cancer risks for difenoconazole was
performed using anticipated residues and PCT or percent imported, as
refinements, for selected commodities, to determine Estimated Lifetime
Cancer Risk for the general population. The DEEM analysis was used, as
described previously, and the partially refined exposure estimate
calculated for the U.S. population (48 contiguous States) was 0.000005
mg/kg/day, translating to a lifetime cancer risk estimate of 8.4 x
10-7 from residues in food. This cancer risk estimate does
not exceed the Agency's level of concern.
    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

[[Page 47683]]

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.
    Anticipated residue data used in the current dietary risk analysis
were calculated from field trial data. The anticipated residues used
were 0.01 ppm for bananas; 0.000019 for eggs; 0.0000043 ppm for egg
whites; 0.000046 ppm for egg yolks; 0.000041 ppm for fat of cattle,
goats, hogs, horses, and sheep; 0.00012 ppm for kidney of cattle,
goats, hogs, horses, and sheep; 0.000014 ppm for meat of cattle, goats,
hogs, horses, and sheep; 0.00044 ppm for meat byproducts (except
kidney) of cattle, goats, hogs, horses, and sheep; 0.000013 ppm for
milk; 0.01 ppm for plantains; 0.0000030 ppm for poultry fat; 0.000034
ppm for poultry kidney; 0.000006 ppm for poultry meat; 0.000023 ppm for
poultry meat byproducts (except kidney); 0.005 ppm for sweet corn; and
0.005 ppm for wheat grain.
    Section 408(b)(2)(F) States that the Agency may use data on the
actual 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 the section 408(b)(2)(F), EPA may require registrants to submit data
on PCT.
    The Agency used PCT information as follows:
    Three PCT for sweet corn, 9 PCT for wheat, and 10.5% imported for
barley. The percent imported data are used in the same way PCT data are
used. This refinement is used because difenoconazole is not registered
for use in the United States. The percentage means that 10.5% of the
barley used (potentially or actually) for human consumption in the
United States is imported; it is even more conservative because it also
assumes that all such imported barley has difenoconazole residues.
    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 difenoconazole may be applied in a particular area.
    2. From drinking water. The Agency lacks sufficient water-related
exposure data to complete a comprehensive drinking water exposure
analysis and risk assessment for difenoconazole. 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 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
ground water. 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 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 on 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 difenoconazole,
they are further discussed in the aggregate risk sections below.
    3. From non-dietary exposure. Difenoconazole is not currently
registered for use on any residential non-food sites. Therefore, there
are no exposures and risks from non-dietary residential exposure.
    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."
    EPA does not have, at this time, available data to determine
whether difenoconazole 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,
difenoconazole 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 difenoconazole 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

[[Page 47684]]

Bifenthrin Pesticide Tolerances (62 FR 62961, November 26, 1997).

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

    1. Acute risk. From the acute dietary (food only) risk assessment,
a high-end exposure estimate was calculated for the population subgroup
of concern, Females 13+ years. For this group, less than 1% of the RfD
is occupied by dietary (food only) exposure. This small percentage of
the acute RfD utilized by this exposure provides assurance that there
is reasonable certainty that no harm will result to both Females 13+
years, and to the prenatal development of infants. Acute effects for
the general population are not expected.
    The maximum estimated concentrations of difenoconazole in surface
and ground water are less than the DWLOCs for difenoconazole as a
contribution to acute aggregate exposure. Therefore, EPA concludes with
reasonable certainty that residues of difenoconazole in drinking water
will not contribute significantly to the aggregate acute human health
risk.
    2. Chronic risk. Using the ARC exposure assumptions described in
this unit, EPA has concluded that aggregate exposure to difenoconazole
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 yr. old), still at <1% of the RfD. This is further
discussed below in the section on infants and children. 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
estimated concentrations of difenoconazole in surface and ground water
are less than the DWLOCs for difenoconazole as a contribution to
chronic aggregate exposure. Therefore, EPA concludes with reasonable
certainty that residues of difenoconazole in drinking water will not
contribute significantly to the aggregate chronic human health risk.
Despite the potential for exposure to difenoconazole 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.
    Since no registered residential uses or exposure scenarios were
identified for short- and intermediate-term exposure, these risk
assessments are not required.
    4. Aggregate cancer risk for U.S. population. The DEEM dietary
exposure analysis used anticipated residues and PCT information for
selected commodities, to estimate the lifetime cancer risk for the
general population. Using the dietary exposure estimate of 0.000005 mg/
kg/day, the lifetime dietary cancer risk was calculated to be 8.4 x
10-7. The estimated average concentrations of difenoconazole
in surface and ground water are less than the DWLOCs for difenoconazole
as a contribution to cancer aggregate exposure. Therefore, EPA
concludes with reasonable certainty that residues which may occur in
drinking water do not contribute significantly to the aggregate chronic
human health risk. Thus, aggregate cancer risk estimates associated
with exposure to difenoconazole from food and water do not exceed
levels of concern.
    5. Determination of safety. Based on these risk assessments, EPA
concludes that there is reasonable certainty that no harm will result
from aggregate exposure to difenoconazole 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 difenoconazole, 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 prenatal and postnatal 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 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
interspecies and intraspecies 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 a developmental study in
rats, the NOAEL for maternal toxicity was 20 mg/kg/day, based upon
statistically significant decreases in maternal body weight gain and
feed consumption at the LOAEL of 100 mg/kg/day. The NOAEL for
developmental toxicity was 100 mg/kg/day, based upon the incidence of
bifid or unilateral ossification of the thoracic vertebrae, and
significant increases in the average number of ossified hyoid and
decreases in the number of sternal centers of ossification. The average
number of ribs was also significantly increased with accompanying
increases in the number of thoracic vertebrae and decreases in the
number of lumbar vertebrae. These effects were observed at the LOAEL of
200 mg/kg/day.
    In a developmental study in rabbits, the NOAEL for maternal
toxicity was 25 mg/kg/day, based upon decreases in body weight gain and
food consumption seen at the LOAEL of 75 mg/kg/day. The developmental
toxicity NOAEL was also 25 mg/kg/day, with increases in post-
implantation loss and resorptions, and decreases in fetal body weight,
seen at the LOAEL of 75 mg/kg/day.
    iii. Reproductive toxicity study. In a 2-generation reproduction
study in rats, the NOAEL for parental toxicity was 25 ppm (1.25 mg/kg/
day), based upon decreased maternal body weight gain at the LOAEL of
250 ppm (12.5 mg/kg/day). The NOAEL for reproductive toxicity was also
25 ppm, based upon decreased pup weights at day 21, at the LOAEL of 250
ppm.
    iv. Prenatal and postnatal sensitivity. The FQPA Safety Factor
Committee recommended that the 10x safety factor for enhanced
sensitivity to infants and children be reduced to a 1x factor, since
the toxicology data base is complete, and there is no indication of
increased susceptibility of rats or rabbit fetuses to prenatal or
postnatal exposure.
    v. Conclusion. There is a complete toxicity data base for
difenoconazole and exposure data are complete or are estimated based on
data that reasonably accounts for potential exposures.
    2. Acute risk. An acute RfD is not established for the general
population, including infants and children, because there were no
effects observed in

[[Page 47685]]

toxicity studies (including maternal toxicity in the rabbit and rat
developmental studies), which were attributable to a single exposure.
Therefore, the Agency concludes that acute risks to infants and
children are negligible.
    3. Chronic risk. Using the exposure assumptions described in this
unit, EPA has concluded that aggregate exposure to difenoconazole from
food will utilize <1% of the RfD for infants and children. 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 estimated average concentrations of difenoconazole in
surface and ground water are less than the Agency's DWLOC for chronic
exposure among nursing infants (<1 year old) to difenoconazole. Despite
the potential for exposure to difenoconazole 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. Since no registered
residential uses or exposure scenarios were identified for short- and
intermediate-term exposure, these risk assessments are not required.
    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 difenoconazole
residues.

IV. Other Considerations

A. Metabolism in Plants and Animals

    The nature of the residues of difenoconazole in plants and animals
is considered to be adequately understood. Based on acceptable
metabolism studies, the Agency concluded that none of the
difenoconazole metabolites warrant inclusion in the tolerance
regulation, separate regulation, inclusion in the dietary risk
assessment, or additional metabolism or toxicological studies.
Therefore, the residue of concern is the parent compound,
difenoconazole per se, as specified in 40 CFR 180.475.

B. Analytical Enforcement Methodology

    An adequate enforcement method (Method AG-575B, MRID# 428065-04) is
available for enforcement purposes. The method is Gas-Liquid
Chromatography, using a nitrogen/phosphorus detector, which has been
validated for wheat, barley, and bananas. EPA expects that this method
will be adequate for these proposed tolerances for sweet corn
commodities as well.
    The method may be requested from: Calvin Furlow, PRRIB, IRSD
(7502C), Office of Pesticide Programs, Environmental Protection Agency,
401 M St., SW., Washington, DC 20460. Office location and telephone
number: Rm 101FF, CM #2, 1921 Jefferson Davis Hwy., Arlington, VA,
(703) 305-5229.

C. Magnitude of Residues.

    Residues of difenoconazole are not expected to exceed 0.1 ppm in/on
corn, sweet (kernel + corn with husk removed); corn, sweet, forage; or
corn, sweet, stover, as a result of the section 18 use. Secondary
residues are not expected in animal commodities as a result of this
use.

D. International Residue Limits.

    There are pending Codex MRLs for this compound in Mexico for oat,
wheat, and barley. There are MRLs for this compound in Australia for
carrots (0.5 ppm), potatoes (0.02 ppm), and bananas (0.5 ppm). There
are no Codex residue limits established for difenoconazole in/on the
sweet corn commodities listed above, and thus harmonization is not an
issue for this action.

E. Rotational Crop Restrictions.

    There is a 30-day plantback restriction for all rotational crops.

V. Conclusion

    Therefore, the tolerances are established for residues of
difenoconazole [(2S,4R)/(2R,4S)/(2R,4R)/(2S,4S)]1-[2-[4-(4-
chlorophenoxy)-2-chlorophenyl]-4-methyl-1,3-dioxolan-2-yl-methyl]-1H-
1,2,4-triazole in/on corn, sweet (kernel + corn with husk removed);
corn, sweet, forage; and corn, sweet, stover at 0.1 ppm.

VI. Objections and Hearing Requests

    The new FFDCA section 408(g) provides essentially the same process
for persons to "object" to a tolerance regulation as was provided in
the old section 408 and in section 409. However, the period for filing
objections is 60 days, rather than 30 days. EPA currently has
procedural regulations which govern the submission of objections and
hearing requests. These regulations will require some modification to
reflect the new law. However, until those modifications can be made,
EPA will continue to use those procedural regulations with appropriate
adjustments to reflect the new law.
    Any person may, by November 1, 1999, file written objections to any
aspect of this regulation and may also request a hearing on those
objections. Objections and hearing requests must be filed with the
Hearing Clerk, at the address given under the "ADDRESSES" section (40
CFR 178.20). A copy of the objections and/or hearing requests filed
with the Hearing Clerk should be submitted to the OPP docket for this
rulemaking. The objections submitted must specify the provisions of the
regulation deemed objectionable and the grounds for the objections (40
CFR 178.25). Each objection must be accompanied by the fee prescribed
by 40 CFR 180.33(i). 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." For
additional information regarding tolerance objection fee waivers,
contact James Tompkins, Registration Division (7505C), Office of
Pesticide Programs, Environmental Protection Agency, 401 M St., SW.,
Washington, DC 20460. Office location, telephone number, and e-mail
address: Rm. 239, CM #2, 1921 Jefferson Davis Hwy., Arlington, VA,
(703) 305-5697, tompkins.jim@epa.gov. Requests for waiver of tolerance
objection fees should be sent to James Hollins, Information Resources
and Services Division (7502C), Office of Pesticide Programs,
Environmental Protection Agency, 401 M St., SW., Washington, DC 20460.
    If a hearing is requested, the objections must include a statement
of the factual issues on which a hearing is requested, the requestor's
contentions on such issues, and a summary of any evidence relied upon
by the requestor (40 CFR 178.27). A request for a hearing will be
granted if the Administrator determines that the material submitted
shows the following: There is 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 in the
manner sought by the requestor would be adequate to justify the action
requested (40 CFR 178.32). 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.

[[Page 47686]]

Information not marked confidential may be disclosed publicly by EPA
without prior notice.

VII. Public Record and Electronic Submissions

    EPA has established a record for this regulation under docket
control number [OPP-300904] (including any comments and data submitted
electronically). A public version of this record, including printed,
paper versions of electronic comments, which does not include any
information claimed as CBI, is available for inspection from 8:30 a.m.
to 4 p.m., Monday through Friday, excluding legal holidays. The public
record is located in Rm. 119 of the Public Information and Records
Integrity Branch, Information Resources and Services Division (7502C),
Office of Pesticide Programs, Environmental Protection Agency, CM #2,
1921 Jefferson Davis Hwy., Arlington, VA.
    Objections and hearing requests may be sent by e-mail directly to
EPA at:
    opp-docket@epa.gov

    E-mailed objections and hearing requests must be submitted as an
ASCII file avoiding the use of special characters and any form of
encryption.
    The official record for this regulation, as well as the public
version, as described in this unit will be kept in paper form.
Accordingly, EPA will transfer any copies of objections and hearing
requests received electronically into printed, paper form as they are
received and will place the paper copies in the official record which
will also include all comments submitted directly in writing. The
official record is the paper record maintained at the Virginia address
in "ADDRESSES" at the beginning of this document.

VIII. Regulatory Assessment Requirements

A. Certain Acts and Executive Orders

    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 any prior consultation
as specified by Executive Order 12875, entitled Enhancing the
Intergovernmental Partnership (58 FR 58093, October 28, 1993), or
special considerations as required by 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).
    In addition, since tolerances and exemptions that are established
on the basis of a petition 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. Nevertheless, the Agency previously
assessed whether establishing tolerances, exemptions from tolerances,
raising tolerance levels or expanding exemptions might adversely impact
small entities and concluded, as a generic matter, that there is no
adverse economic impact. The factual basis for the Agency's generic
certification for tolerance actions published on May 4, 1981 (46 FR
24950), and was provided to the Chief Counsel for Advocacy of the Small
Business Administration.

B. Executive Order 12875

    Under Executive Order 12875, entitled Enhancing the
Intergovernmental Partnership (58 FR 58093, October 28, 1993), EPA may
not issue a regulation that is not required by statute and that creates
a mandate upon a State, local or tribal government, unless the Federal
government provides the funds necessary to pay the direct compliance
costs incurred by those governments. If the mandate is unfunded, EPA
must provide to OMB a description of the extent of EPA's prior
consultation with representatives of affected State, local, and tribal
governments, the nature of their concerns, copies of any written
communications from the governments, and a statement supporting the
need to issue the regulation. In addition, Executive Order 12875
requires EPA to develop an effective process permitting elected
officials and other representatives of State, local, and tribal
governments "to provide meaningful and timely input in the development
of regulatory proposals containing significant unfunded mandates."
    Today's rule does not create an unfunded Federal mandate on State,
local, or tribal governments. The rule does not impose any enforceable
duties on these entities. Accordingly, the requirements of section 1(a)
of Executive Order 12875 do not apply to this rule.

C. Executive Order 13084

    Under Executive Order 13084, entitled Consultation and Coordination
with Indian Tribal Governments (63 FR 27655, May 19, 1998), EPA may not
issue a regulation that is not required by statute, that significantly
or uniquely affects the communities of Indian tribal governments, and
that imposes substantial direct compliance costs on those communities,
unless the Federal government provides the funds necessary to pay the
direct compliance costs incurred by the tribal governments. If the
mandate is unfunded, EPA must provide OMB, in a separately identified
section of the preamble to the rule, a description of the extent of
EPA's prior consultation with representatives of affected tribal
governments, a summary of the nature of their concerns, and a statement
supporting the need to issue the regulation. In addition, Executive
Order 13084 requires EPA to develop an effective process permitting
elected officials and other representatives of Indian tribal
governments "to provide meaningful and timely input in the development
of regulatory policies on matters that significantly or uniquely affect
their communities."
    Today's rule does not significantly or uniquely affect the
communities of Indian tribal governments. This action does not involve
or impose any requirements that affect Indian tribes. Accordingly, the
requirements of section 3(b) of Executive Order 13084 do not apply to
this rule.

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 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 the 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,

[[Page 47687]]

Agricultural commodities, Pesticides and pests, Reporting and
recordkeeping requirements.

    Dated: August 13, 1999.

James Jones,
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), 346a and 371.

    2. In Sec. 180.475, by adding paragraph (b) to read as follows:

Sec. 180.475  Difenoconazole; tolerances for residues.

*    *    *    *    *
    (b) Section 18 emergency exemptions. Time-limited tolerances are
established for residues of difenoconazole 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
------------------------------------------------------------------------
Corn, sweet (kernel + corn with   0.1                 1/31/01
 husk removed).
Corn, sweet, forage.............  0.1                 1/31/01
Corn, sweet, stover.............  0.1                 1/31/01
------------------------------------------------------------------------

*    *    *    *    *

[FR Doc. 99-22635 Filed 8-31-99; 8:45 am]
BILLING CODE 6560-50-F