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Tebuconazole; Pesticide Tolerances for Emergency Exemptions
Note: EPA no longer updates this information, but it may be useful as a reference or resource.
[Federal Register: October 29, 1997 (Volume 62, Number 209)]
[Rules and Regulations]
[Page 56089-56095]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr29oc97-27]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 180
[OPP-300570; FRL-5752-4]
RIN 2070-AB78
Tebuconazole; 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 tebuconazole in or on sunflower seed and sunflower oil.
This action is in response to an emergency exemption under section 18
of the Federal Insecticide, Fungicide, and Rodenticide Act authorizing
use of the pesticide on sunflowers. This regulation establishes a
maximum permissible level for residues of tebuconazole in these food
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 September 30, 1998.
DATES: This regulation is effective October 29, 1997. Objections and
requests for hearings must be received by EPA on or before December 29,
1997.
ADDRESSES: Written objections and hearing requests, identified by the
docket control number, [OPP-300570], 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-300570], 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. 1132, 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@epamail.epa.gov. Copies of 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 file
format or ASCII file format. All copies of objections and hearing
requests in electronic form must be identified by the docket control
number [OPP-300570]. No Confidential Business Information (CBI) should
be submitted through e-mail. Electronic copies of objections and
hearing requests on this rule may be filed online at many Federal
Depository Libraries.
FOR FURTHER INFORMATION CONTACT: By mail: Daniel Rosenblatt,
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: Crystal Mall #2,
1921 Jefferson Davis Hwy., Arlington, VA, (703) 308-9375, e-mail:
rosenblatt.dan@epamail.epa.gov.
SUPPLEMENTARY INFORMATION: EPA, on its own initiative, pursuant to
section 408(e) and (l)(6) of the Federal Food, Drug, and Cosmetic Act
(FFDCA), 21 U.S.C. 346a(e) and (l)(6), is establishing tolerances for
residues of the fungicide tebuconazole, in or on sunflower seed and
sunflower oil at 0.2 and 0.4 parts per million (ppm). These tolerances
will expire and are revoked on September 30, 1998. EPA will publish a
document in the Federal Register to remove the revoked tolerances from
the Code of Federal Regulations.
I. Background and Statutory Authority
The Food Quality Protection Act of 1996 (FQPA) (Pub. L. 104-170)
was signed into law August 3, 1996. FQPA amends both the Federal Food,
Drug, and Cosmetic Act (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 below 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).
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
[[Page 56090]]
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 tolerance to set binding precedents for the
application of section 408 and the new safety standard to other
tolerances and exemptions.
II. Emergency Exemption for Tebuconazole on Sunflower Seeds and
Sunflower Oil and FFDCA Tolerances
Agriculture officials in states where the sunflower is produced
commercially have identified sunflower rust, caused by the pathogen
Puccinia helianthi, as a severe threat to crop yields. Information on
the anticipated yield loss if tebuconazole were not used indicates that
losses would be quite significant. One state suggested that losses
could be as high as 80% for specific locations. Earlier this year, the
States of Kansas, Colorado, and North Dakota determined that conditions
may be favorable for a sunflower rust outbreak. Consequently, these
states invoked their authorities pursuant to 40 CFR 166.40 to declare a
crisis situation. EPA considered the health and safety implications of
these actions and permitted the crisis actions to go forward.
Therefore, EPA has authorized under FIFRA section 18 the use of
tebuconazole on sunflower seed and sunflower oil for control of rust
(Puccinia helianthi) in Colorado, North Dakota, and Kansas.
As part of its assessment of this emergency exemption, EPA assessed
the potential risks presented by residues of tebuconazole in or on
sunflower seed and sunflower oil. In doing so, EPA considered the new
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 new safety standard and with FIFRA section 18. Consistent with
the need to move quickly on emergency exemptions 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 September 30, 1998, under FFDCA section 408(l)(5), residues
of the pesticide not in excess of the amounts specified in the
tolerances remaining in or on sunflower seed and sunflower oil after
that date will not be unlawful, provided the pesticide is applied in a
manner that was lawful under FIFRA. 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 tebuconazole
meets EPA's registration requirements for use on sunflower or whether
permanent tolerances for this use would be appropriate. Under these
circumstances, EPA does not believe that these tolerances serve as a
basis for registration of tebuconazole 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 Colorado, North Dakota and Kansas to use
this pesticide on this crop under section 18 of FIFRA without following
all provisions of section 18 as identified in 40 CFR part 166. For
additional information regarding the emergency exemption for
tebuconazole, contact the Agency's Registration Division at the address
provided above.
III. Risk Assessment and Statutory Findings
EPA performs a number of analyses to determine the risks from
aggregate exposure to pesticide residues. First, EPA determines the
toxicity of pesticides based primarily on toxicological studies using
laboratory animals. These studies address many adverse health effects,
including (but not limited to) reproductive effects, developmental
toxicity, toxicity to the nervous system, and carcinogenicity. Second,
EPA examines exposure to the pesticide through the diet (e.g., food and
drinking water) and through exposures that occur as a result of
pesticide use in residential settings.
A. Toxicity
1. Threshold and non-threshold effects. For many animal studies, a
dose response relationship can be determined, which provides a dose
that causes adverse effects (threshold effects) and doses causing no
observed effects (the ``no-observed effect level'' or ``NOEL'').
Once a study has been evaluated and the observed effects have been
determined to be threshold effects, EPA generally divides the NOEL from
the study with the lowest NOEL by an uncertainty factor (usually 100 or
more) to determine the Reference Dose (RfD). The RfD is a level at or
below which daily aggregate exposure over a lifetime will not pose
appreciable risks to human health. An uncertainty factor (sometimes
called a ``safety factor'') of 100 is commonly used since it is assumed
that people may be up to 10 times more sensitive to pesticides than the
test animals, and that one person or subgroup of the population (such
as infants and children) could be up to 10 times more sensitive to a
pesticide than another. In addition, EPA assesses the potential risks
to infants and children based on the weight of the evidence of the
toxicology studies and determines whether an additional uncertainty
factor is warranted. Thus, an aggregate daily exposure to a pesticide
residue at or below the RfD (expressed as 100% or less of the RfD) is
generally considered acceptable by EPA. EPA generally uses the RfD to
evaluate the chronic risks posed by pesticide exposure. For shorter
term risks, EPA calculates a margin of exposure (MOE) by dividing the
estimated human exposure into the NOEL from the appropriate animal
study. Commonly, EPA finds MOEs lower than 100 to be unacceptable. This
100-fold MOE is based on the same rationale as the 100-fold uncertainty
factor.
[[Page 56091]]
Lifetime feeding studies in two species of laboratory animals are
conducted to screen pesticides for cancer effects. When evidence of
increased cancer is noted in these studies, the Agency conducts a
weight of the evidence review of all relevant toxicological data
including short-term and mutagenicity studies and structure activity
relationship. Once a pesticide has been classified as a potential human
carcinogen, different types of risk assessments (e.g., linear low dose
extrapolations or MOE calculation based on the appropriate NOEL) will
be carried out based on the nature of the carcinogenic response and the
Agency's knowledge of its mode of action.
2. Differences in toxic effect due to exposure duration. The
toxicological effects of a pesticide can vary with different exposure
durations. EPA considers the entire toxicity data base, and based on
the effects seen for different durations and routes of exposure,
determines which risk assessments should be done to assure that the
public is adequately protected from any pesticide exposure scenario.
Both short and long durations of exposure are always considered.
Typically, risk assessments include ``acute,'' ``short-term,''
``intermediate term,'' and ``chronic'' risks. These assessments are
defined by the Agency as follows.
Acute risk, by the Agency's definition, results from 1-day
consumption of food and water, and reflects toxicity which could be
expressed following a single oral exposure to the pesticide residues.
High end exposure to food and water residues are typically assumed.
Short-term risk results from exposure to the pesticide for a period
of 1-7 days, and therefore overlaps with the acute risk assessment.
Historically, this risk assessment was intended to address primarily
dermal and inhalation exposure which could result, for example, from
residential pesticide applications. However, since enaction of FQPA,
this assessment has been expanded to include both dietary and non-
dietary sources of exposure, and will typically consider exposure from
food, water, and residential uses when reliable data are available. In
this assessment, risks from average food and water exposure, and high-
end residential exposure, are aggregated. High-end exposures from all 3
sources are not typically added because of the very low probability of
this occurring in most cases, and because the other conservative
assumptions built into the assessment assure adequate protection of
public health. However, for cases in which high-end exposure can
reasonably be expected from multiple sources (e.g. frequent and
widespread homeowner use in a specific geographical area), multiple
high-end risks will be aggregated and presented as part of the
comprehensive risk assessment/characterization. Since the toxicological
endpoint considered in this assessment reflects exposure over a period
of at least 7 days, an additional degree of conservatism is built into
the assessment; i.e., the risk assessment nominally covers 1-7 days
exposure, and the toxicological endpoint/NOEL is selected to be
adequate for at least 7 days of exposure. (Toxicity results at lower
levels when the dosing duration is increased.)
Intermediate-term risk results from exposure for 7 days to several
months. This assessment is handled in a manner similar to the short-
term risk assessment.
Chronic risk assessment describes risk which could result from
several months to a lifetime of exposure. For this assessment, risks
are aggregated considering average exposure from all sources for
representative population subgroups including infants and children.
B. Aggregate Exposure
In examining aggregate exposure, FFDCA section 408 requires that
EPA take into account available and reliable information concerning
exposure from the pesticide residue in the food in question, residues
in other foods for which there are tolerances, residues in groundwater
or surface water that is consumed as drinking water, and other non-
occupational exposures through pesticide use in gardens, lawns, or
buildings (residential and other indoor uses). Dietary exposure to
residues of a pesticide in a food commodity are estimated by
multiplying the average daily consumption of the food forms of that
commodity by the tolerance level or the anticipated pesticide residue
level. The Theoretical Maximum Residue Contribution (TMRC) is an
estimate of the level of residues consumed daily if each food item
contained pesticide residues equal to the tolerance. In evaluating food
exposures, EPA takes into account varying consumption patterns of major
identifiable subgroups of consumers, including infants and children.
The TMRC is a ``worst case'' estimate since it is based on the
assumptions that food contains pesticide residues at the tolerance
level and that 100% of the crop is treated by pesticides that have
established tolerances. If the TMRC exceeds the RfD or poses a lifetime
cancer risk that is greater than approximately one in a million, EPA
attempts to derive a more accurate exposure estimate for the pesticide
by evaluating additional types of information (anticipated residue data
and/or percent of crop treated data) which show, generally, that
pesticide residues in most foods when they are eaten are well below
established tolerances.
Percent of crop treated estimates are derived from federal and
private market survey data. 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 percent of crop
treated, the Agency is reasonably certain that exposure is not
understated for any significant subpopulation group. Further, regional
consumption information is taken into account through EPA's computer-
based model for evaluating the exposure of significant subpopulations
including several regional groups, to pesticide residues. For this
pesticide, the most highly exposed population subgroup (non-nursing
infants less than a year old) was not regionally based.
IV. Aggregate Risk Assessment and Determination of Safety
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
tebuconazole and to make a determination on aggregate exposure,
consistent with section 408(b)(2), for a time-limited tolerance for
residues of tebuconazole on sunflower seed and sunflower oil at 0.2 and
0.4 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 tebuconazole are
discussed below.
1. Acute toxicity. For acute dietary risk assessment, OPP
recommended use of the developmental NOEL of 10 mg/kg/day from the
developmental toxicity study in mice. Effects observed at the lowest
observed effect level (LOEL) of 30 mg/kg/day are an increased number of
runts and fetuses with malformations of the skull, brain, and spinal
cord. The
[[Page 56092]]
population subgroup of concern for this acute dietary risk assessment
is females (13+ years old).
2. Short - and intermediate - term toxicity. [OPP has determined
that short- and intermediate-term inhalation risk assessments and
short-term dermal risk assessments are appropriate for non-
occupational, non-dietary routes of exposure. OPP recommends that the
NOEL of 1,000 mg/kg/day, taken from the dermal developmental toxicity
study in mice, be used for the short-term dermal MOE calculations. This
NOEL was the highest dose tested in the study. For short- and
intermediate-term inhalation MOE calculations, OPP recommends using the
NOEL of 0.0106 mg/L/day (1.75 mg/kg/day), based on liver toxicity and
piloerection at the LOEL of 0.1558 mg/L/day (25.7 mg/kg/day) in the 3-
week inhalation rat toxicity study.
3. Chronic toxicity. EPA has established the RfD for tebuconazole
at 0.03 milligrams/kilogram/day (mg/kg/day). This RfD is based on the
NOEL of 2.96 mg/kg/day from a 1-year dog feeding study. Adrenal effects
(fatty change and hypertrophy) were observed at the LOEL of 4.39 mg/kg/
day. An uncertainty factor (UF) of 100 was applied to account for both
interspecies and intra species variability.
4. Carcinogenicity. OPP's Cancer Peer Review Committee (CPRC) has
determined that tebuconazole is a Group C (possible human carcinogen)
chemical, based on mouse liver tumors in both sexes (adenomas and
carcinomas in males and carcinomas in females) at 280 mg/kg/day, the
highest dose tested. OPP recommends using the RfD approach for
quantification of human risk. Therefore, the RfD is deemed protective
of all chronic human health effects, including cancer.
B. Exposures and Risks
1. From food and feed uses. Tolerances have been established (40
CFR 180.474) for parent tebuconazole (alpha-[2-(4-chlorophenyl)-ethyl]-
alpha-1,1-dimethylethyl)-1H-1,2,4-triazole-1-ethanol), in or on a
variety of raw agricultural commodities The established levels range
from 0.05 ppm in barley, oat and wheat grain to 4.0 ppm in cherries and
peanut hulls. Risk assessments were conducted by EPA to assess dietary
exposures and risks from tebuconazole 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 one day or single exposure. For the purpose of assessing potential
acute dietary risks, tolerance level residues and 100% of crop treated
to estimate the TMRC for major identifiable subgroups of consumers. An
MOE of 889 was calculated for females 13+ years, the populations
subgroup of concern. The high end exposure value was 0.01125 mg/kg/day.
ii. Chronic exposure and risk. For the purpose of assessing
potential chronic dietary exposure from tebuconazole, EPA assumed
tolerance level residues and 100% of crop treated to estimate the TMRC
for major identifiable subgroups of consumers. The tolerances for
tebuconazole result in a TMRC that is equivalent to the following range
of RfD percentages: U.S. populations (48 states) 6% to non-nursing
infants (<1 year old) 32%.
2. From drinking water. There are no groundwater data for
tebuconazole. In addition, no maximum concentration levels or Health
Advisories have been established for the pesticide.
Because the Agency lacks sufficient water-related exposure data to
complete a comprehensive drinking water risk assessment for many
pesticides, EPA has commenced and nearly completed a process to
identify a reasonable yet conservative bounding figure for the
potential contribution of water-related exposure to the aggregate risk
posed by a pesticide. In developing the bounding figure, EPA estimated
residue levels in water for a number of specific pesticides using
various data sources. The Agency then applied the estimated residue
levels, in conjunction with appropriate toxicological endpoints (RfD's
or acute dietary NOEL's) and assumptions about body weight and
consumption, to calculate, for each pesticide, the increment of
aggregate risk contributed by consumption of contaminated water. While
EPA has not yet pinpointed the appropriate bounding figure for exposure
from contaminated water, the ranges the Agency is continuing to examine
are all below the level that would cause tebuconazole to exceed the RfD
even with the inclusion of the tolerances being granted in this
document. The Agency has therefore concluded that the potential
exposures associated with tebuconazole in water, even at the higher
levels the Agency is considering as a conservative upper bound, would
not prevent the Agency from determining that there is a reasonable
certainty of no harm if the tolerance is granted.
3. From non-dietary exposure. Tebuconazole is not currently
registered for indoor or outdoor residential uses. Thus, no non-
dietary, non-occupational exposure is expected.
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.'' The Agency believes that ``available
information'' in this context might include not only toxicity,
chemistry, and exposure data, but also scientific policies and
methodologies for understanding common mechanisms of toxicity and
conducting cumulative risk assessments. For most pesticides, although
the Agency has some information in its files that may turn out to be
helpful in eventually determining whether a pesticide shares a common
mechanism of toxicity with any other substances, EPA does not at this
time have the methodologies to resolve the complex scientific issues
concerning common mechanism of toxicity in a meaningful way. EPA has
begun a pilot process to study this issue further through the
examination of particular classes of pesticides. The Agency hopes that
the results of this pilot process will increase the Agency's scientific
understanding of this question such that EPA will be able to develop
and apply scientific principles for better determining which chemicals
have a common mechanism of toxicity and evaluating the cumulative
effects of such chemicals. The Agency anticipates, however, that even
as its understanding of the science of common mechanisms increases,
decisions on specific classes of chemicals will be heavily dependent on
chemical specific data, much of which may not be presently available.
Although at present the Agency does not know how to apply the
information in its files concerning common mechanism issues to most
risk assessments, there are pesticides as to which the common mechanism
issues can be resolved. These pesticides include pesticides that are
toxicologically dissimilar to existing chemical substances (in which
case the Agency can conclude that it is unlikely that a pesticide
shares a common mechanism of activity with other substances) and
pesticides that produce a common toxic metabolite (in which case common
mechanism of activity will be assumed).
EPA does not have, at this time, available data to determine
whether tebuconazole has a common mechanism of toxicity with other
substances or how to include this pesticide in a cumulative risk
assessment. Unlike other pesticides
[[Page 56093]]
for which EPA has followed a cumulative risk approach based on a common
mechanism of toxicity, tebuconazole 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 tebuconazole has
a common mechanism of toxicity with other substances.
C. Aggregate Risks and Determination of Safety for U.S. Population
1. Acute risk. EPA has concluded that for the population subgroup
of concern, females 13+ years), acute aggregate exposure to
tebuconazole from existing and proposed food uses will result in an MOE
of 889. Despite the potential for exposure to tebuconazole in drinking
water, EPA does not expect the aggregate exposure to exceed the level
of concern for acute dietary exposure. EPA concludes that there is a
reasonable certainty that no harm will result from aggregate exposure
to tebuconazole residues.
2. Chronic risk. Using the TMRC exposure assumptions described
above, EPA has concluded that aggregate exposure to tebuconazole from
food will utilize 6% of the RfD for the U.S. population. The major
identifiable subgroup with the highest aggregate exposure is non-
nursing infants less than 1 year old (discussed below). EPA generally
has no concern for exposures below 100% of the RfD because the RfD
represents the level at or below which daily aggregate dietary exposure
over a lifetime will not pose appreciable risks to human health.
Despite the potential for exposure to tebuconazole in drinking water
and from non-dietary, non-occupational exposure, EPA does not expect
the aggregate exposure to exceed 100% of the RfD. EPA concludes that
there is a reasonable certainty that no harm will result from aggregate
exposure to tebuconazole residues.
D. Aggregate Cancer Risk for U.S. Population
Tebuconazole has been classified as a Group C (possible human
carcinogen) chemical by EPA, with the recommendation that the RfD
approach be used to assess cancer risk. A quantitative cancer risk was
not performed because human health risk concerns due to long-term
exposure to tebuconazole residues are adequately addressed by the
aggregate chronic exposure analysis using the RfD.
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 tebuconazole, EPA considered data from
developmental toxicity studies in the rat and rabbit and a two-
generation reproduction study in the rat. The developmental toxicity
studies are designed to evaluate adverse effects on the developing
organism resulting from maternal pesticide exposure during gestation.
Reproduction studies provide information relating to effects from
exposure to the pesticide on the reproductive capability of mating
animals and data on systemic toxicity.
FFDCA section 408 provides that EPA shall apply an additional
tenfold margin of safety for infants and children in the case of
threshold effects to account for pre-and post-natal toxicity and the
completeness of the database 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 100-
fold safety factor (usually 100 for combined inter- and intra-species
variability) and not the additional tenfold 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 safety factor.
ii. Developmental toxicity studies. From the rat developmental
study, the maternal NOEL was 30 mg/kg/day, based on increased liver
weight at the LOEL of 60 mg/kg/day. The developmental NOEL was 30 mg/
kg/day, based on delayed ossification and supernumerary ribs at the
developmental LOEL of 60 mg/kg/day. In the rabbit developmental study,
the maternal NOEL was 30 mg/kg/day, based on decreased weight gain and
food consumption at the maternal LOEL of 100 mg/kg/day. The
developmental NOEL was 30 mg/kg/day, based on increased resorptions due
to post-implantation loss at the developmental LOEL of 100 mg/kg/day.
The maternal NOEL in the mouse study was 10 mg/kg/day, with reduced
hematocrit occurring at the maternal LOEL of 30 mg/kg/day in the oral
development toxicity study. The developmental NOEL was 10 mg/kg/day,
with effects at the LOEL of 30 mg/kg/day being an increased number of
runts, and fetuses with malformations of the skull, brain and spinal cord.
iii. Reproductive toxicity study. In the 2-generation rat
reproduction study, the parental NOEL was 15 mg/kg/day, based on
decreased body weight and increased spleen weight at the LOEL of 50 mg/
kg/day. The reproductive NOEL was 15 mg/kg/day, with decreased body
weight of neonates being the effect at the LOEL of 50 mg/kg/day.
iv. Pre- and post-natal sensitivity. The pre- and post-natal
toxicology data base for tebuconazole is complete with respect to
current toxicological data requirements. The developmental toxicity
studies in rats, rabbits, and mice had developmental findings occurring
at the same dose levels (NOELs and LOELs) as maternal effects,
indicating no extra pre-natal sensitivity.
The reproductive toxicity study in rats did not demonstrate any
extra pre- or post-natal sensitivity to infants and children since the
NOEL and LOEL of 15 and 50 mg/kg/day, respectively, were the same for
both parental and pup toxicity. Additionally, the decreased body weight
gain in parental animals was also observed in pups.
v. Conclusion. Based on the above, EPA concludes that reliable data
support use of the standard 100-fold uncertainty factor and that an
additional safety factor is not needed to protect infants and children.
2. Acute risk. The acute dietary (food only) MOE for females 13+
years (accounts for both maternal and fetal exposure) was calculated to
be 889. This MOE calculation was based on the developmental NOEL in
mice of 10 mg/kg/day. Maternal effects observed at the LOEL of 30 mg/
kg/day included a reduced hematocrit. This assessment assumed 100%
crop-treated with tolerance level residues on all treated crops
consumed, resulting in a significant over-estimate of dietary exposure.
No data were available for potential exposures of tebuconazole in
drinking water. However, EPA does not expect that aggregate exposure
(food plus water) would result in an unacceptable acute dietary MOE.
EPA concludes that the large acute dietary MOE provides assurance that
there is a reasonable certainty of no harm for both females 13+ years
and the pre-natal development of infants.
3. Chronic risk. Using the conservative exposure assumptions
described above, EPA has concluded that aggregate exposure to
tebuconazole from food will utilize between 9% for children (7-12 years
old) to 32% for non-nursing infants (less that 1 year old). 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
[[Page 56094]]
exposure over a lifetime will not pose appreciable risks to human
health. Despite the potential for exposure to tebuconazole in drinking
water and from non-dietary, non-occupational exposure, EPA does not
expect the aggregate exposure to exceed 100% of the RfD. EPA concludes
that there is a reasonable certainty that no harm will result to
infants and children from aggregate exposure to tebuconazole residues.
V. Other Considerations
A. Metabolism In Plants and Animals
The nature of tebuconazole residues in plants and animals is
adequately understood. The residue of concern in plants is tebuconazole
per se. In ruminants and poultry, the residue of concern is the parent
compound and its 1-(4-chlorophenyl)-4,4-dimethyl-3-(1H-1,2,4-triazole-
1-yl-methyl)-pentane-3,5-diol metabolite (HGW 2061).
B. Analytical Enforcement Methodology
Adequate enforcement methodology is available to enforce the
tolerance expressions. The gas chromatographic method entitled ``Gas
Chromatographic Method for Determination of Residues of Tebuconazole in
Crops, Processed Products, Soil and Water'' is adequate to enforce
time-limited tolerances for tebuconazole per se residues in/on
sunflower seed and oil to support compliance efforts. The gas
chromatographic method entitled ``An Analytical Residue Method for the
Determination of Tebuconazole and HWG 2061 Residues in Bovine and
Poultry Tissues, Milk and Eggs'' is adequate to enforce the time-
limited tolerances presently established for the combined residues of
tebuconazole and HWG 2061 in animal commodities.
C. Magnitude of Residues
Residues of tebuconazole per se are not expected to exceed 0.2 ppm
in sunflower seed as a result of this use. Sunflower hulls and forage
do not require regulation as they are not considered livestock feed items.
D. International Residue Limits
There are no Canadian, Mexican, or Codex maximum residue limits for
tebuconazole on sunflowers.
E. Rotational Crop Restrictions
Product labels for tebuconazole are to carry a plant back interval
of 120 days after the last application for crops which are not on the
label.
VI. Conclusion
Therefore, tolerances are established for residues of tebuconazole
in sunflower seed and sunflower oil at 0.2 ppm and 0.4 ppm.
VII. Objections and Hearing Requests
The new FFDCA section 408(g) provides essentially the same process
for persons to ``object'' to a tolerance regulation issued by EPA under
new section 408(e) and (l)(6) 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 December 29, 1997, 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 above (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). 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. Information not marked confidential may be disclosed publicly
by EPA without prior notice.
VIII. Public Docket
EPA has established a record for this rulemaking under docket
control number [OPP-300570] (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 Room 1132 of the Public Information and Records
Integrity Branch, Information Resources and Services Division (7502C),
Office of Pesticide Programs, Environmental Protection Agency, Crystal
Mall #2, 1921 Jefferson Davis Hwy., Arlington, VA.
Electronic comments may be sent directly to EPA at:
opp-docket@epamail.epa.gov.
Electronic comments must be submitted as an ASCII file avoiding the
use of special characters and any form of encryption.
The official record for this rulemaking, as well as the public
version, as described above 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 rulemaking record which
will also include all comments submitted directly in writing. The
official rulemaking record is the paper record maintained at the
Virginia address in ``ADDRESSES'' at the beginning of this document.
IX. Regulatory Assessment Requirements
This final rule establishes time-limited tolerances under FFDCA
section 408(1)(6). 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) (Pub. L. 104-4). Nor does it require any
prior consultation as specified by Executive Order 12875, entitled
Enhancing the
[[Page 56095]]
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 these tolerances and exemptions that are
established under FFDCA section 408 (1)(6), such as the tolerances in
this final rule, do not require the issuance of a proposed rule, the
requirements of the Regulatory Flexibility Act (RFA) (5 U.S.C. 601 et
seq.) do not apply. Nevertheless, the Agency has 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.
X. Submission to Congress and the General Accounting Office
Under 5 U.S.C. 801(a)(1)(A), as added by the Small Business
Regulatory Enforcement Fairness Act of 1996, the Agency has submitted 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 General Accounting Office prior to publication of this rule in
today's Federal Register. This is not a ``major rule'' as defined by 5
U.S.C. 804(2).
List of Subjects in 40 CFR Part 180
Environmental protection, Administrative practice and procedure,
Agricultural commodities, Pesticides and pests, Reporting and
recordkeeping requirements.
Dated: October 17, 1997.
James Jones,
Acting Director, Registration Division, Office of Pesticide Programs.
Therefore, 40 CFR chapter I is amended as follows:
PART 180-- [AMENDED]
1. The authority citation for part 180 continues to read as
follows:
Authority: 21 U.S.C. 346a and 371.
2. In Sec. 180.474, paragraph (b)(1) is amended by alphabetically
adding the following commodities to the table to read as follows:
Sec. 180.474 Tebuconazole; tolerances for residues.
* * * * *
(b) Section 18 emergency exemptions. (1) * * *
------------------------------------------------------------------------
Expiration/
Commodity Parts per million Revocation Date
------------------------------------------------------------------------
* * * * *
* *
Sunflower oil................... 0.4 9/30/98
Sunflower seed.................. 0.2 9/30/98
* * * * *
* *
------------------------------------------------------------------------
* * * * *
[FR Doc. 97-28656 Filed 10-28-97; 8:45 am]
BILLING CODE 6560-50-F