[Federal Register Volume 64, Number 169 (Wednesday, September 1, 1999)]
[Rules and Regulations]
[Pages 47680-47687]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-22635]


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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: [email protected]. 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, 
[email protected].

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, [email protected]. 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:
    [email protected]

    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