![[logo] US EPA](http://www.epa.gov/epafiles/images/logo_epaseal.gif){kind=logo}
Tebuconazole; Pesticide Tolerance for Emergency Exemption
Note: EPA no longer updates this information, but it may be useful as a reference or resource.
[Federal Register: June 20, 1997 (Volume 62, Number 119)]
[Rules and Regulations]
[Page 33550-33557]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr20jn97-11]
-----------------------------------------------------------------------
ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 180
[OPP-300506; FRL-5725-7]
RIN 2070-AB78
Tebuconazole; Pesticide Tolerance for Emergency Exemption
AGENCY: Environmental Protection Agency (EPA).
ACTION: Final rule.
-----------------------------------------------------------------------
SUMMARY: This regulation establishes time-limited tolerances for
residues of the fungicide tebuconazole in or on barley grain, barley
hay, barley straw, wheat hay, wheat straw, pistachios, milk, and meat
byproducts of cattle, goats, hogs, horses, poultry and sheep in
connection with EPA's granting of emergency exemptions under section 18
of the Federal Insecticide, Fungicide, and Rodenticide Act. These
tolerances will expire and are revoked on June 30, 1998.
DATES: This regulation becomes effective June 20, 1997. Objections and
requests for hearings must be received by EPA on or before August 19,
1997.
ADDRESSES: Written objections and hearing requests, identified by the
docket control number, [OPP-300506], 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-300506], must be submitted to: Public Information
and Records Integrity Branch, Information Resources and Services
Division (7506C), 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
[[Page 33551]]
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-
300506]. 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: Stephen Schaible,
Registration Division (7505W), Office of Pesticide Programs,
Environmental Protection Agency, 401 M St., SW., Washington, DC 20460.
Office location, telephone number, and e-mail: Second Floor, Crystal
Mall #2, Rm. 267, 1921 Jefferson Davis Highway, Arlington, VA 22202.
(703) 308-9362, e-mail: schaible.stephen@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
the residues of the fungicide tebuconazole (alpha-[2-(4-chlorophenyl)-
ethyl]-alpha-(1,1-dimethylethyl)-1H-1,2,4-triazole-1-ethanol) in or on
barley grain at 2.0 parts per million (ppm), barley hay at 20 ppm,
barley straw at 20 ppm, wheat hay at 15 ppm, wheat straw at 2.0 ppm,
and pistachios at 1.0 ppm; the currently established tolerance of 0.05
ppm for wheat grain is adequate to cover any residues in wheat grain
expected from these section 18 uses. EPA is establishing tolerances for
the combined residues of tebuconazole and its 1-(4-chlorophenyl)-4,4-
dimethyl-3-(1H-1,2,4-triazole-1-yl-methyl)-pentane-3,5-diol metabolite
(HGW 2061), hereafter referred to in this document as tebuconazole, in
milk at 0.1 ppm and in meat byproducts of cattle, goats, hogs, horses,
poultry and sheep at 0.2 ppm. These tolerances will expire and are
revoked on June 30, 1998. After June 30, 1998, EPA will publish a
document in the Federal Register to remove the revoked tolerance 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 FFDCA, 21
U.S.C. 301 et seq., and the Federal Insecticide, Fungicide, and
Rodenticide Act (FIFRA), 7 U.S.C. 136 et seq. Among other things, FQPA
amends FFDCA to bring all EPA pesticide tolerance-setting activities
under 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 CFR 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 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 Exemptions for Tebuconazole on Barley, Pistachios,
and Wheat and FFDCA Tolerances
On April 16, 1997, the Louisiana Department of Agriculture and
Forestry availed of itself the authority to declare the existence of a
crisis situation within its state, thereby authorizing use under FIFRA
section 18 of tebuconazole on wheat to control rust. On April 21 and
April 25, the Mississippi Department of Agriculture and Commerce and
the Arkansas State Plant Board, respectively, followed suit by
declaring crisis situations within their states for the same pest.
Unusually wet and cool weather this year are to blame for this disease
outbreak. Triadimefon is registered for use on wheat, but existing
stocks have been depleted; other registered alternatives, including
tebuconazole, do not allow application at a sufficiently late stage to
control rust. These emergency exemptions allow application later in the
growth stage of wheat than is currently specified on the existing
label. The Washington Department of Agriculture has requested a
specific exemption for the use of tebuconazole on wheat to control
stripe rust; a similar situation exists in which application of
registered alternatives is not allowed at the later growth stages
needed to control the disease. The Oregon, Washington and Idaho
Departments of Agriculture have requested specific exemptions for the
use of tebuconazole on barley to control rust, and North Dakota and
Minnesota have requested use of this chemical on this crop to control
head blight. The California Environmental Protection Agency, Department
of Pesticide Regulation, has requested a specific exemption for the use
of tebuconazole on pistachios to control late blight. After having
reviewed these submissions, EPA concurs that emergency conditions exist
for these states.
As part of its assessment of these emergency exemptions, EPA
assessed the potential risks presented by residues of tebuconazole in
or on wheat, barley, and pistachios, as well as potential risks
presented by secondary residues in milk and meat byproducts of cattle,
goats, hogs, horses, poultry and sheep. 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.
These tolerances will permit the marketing of these commodities treated
in accordance with the provisions of the section 18 emergency
exemptions. Consistent with the need to
[[Page 33552]]
move quickly on these emergency exemptions in order to address urgent
non-routine situations 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 June 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 these commodities after that date will not be
unlawful, provided the pesticide is applied in a manner that is 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 barley, wheat, or
pistachios or whether permanent tolerances for these uses 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 States other than those listed
above to use this pesticide on these crops under section 18 of FIFRA
without following all provisions of section 18 as identified in 40 CFR
part 166. For additional information regarding these emergency
exemptions 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 percent 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 hundredfold margin of exposure is based on the same
rationale as the hundredfold uncertainty factor.
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 margin of exposure 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''. 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 to 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
three 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 to 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
[[Page 33553]]
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 percent 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 < 1 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
these actions. Tebuconazole is already registered by EPA for numerous
food uses. For the purpose of these emergency exemptions, EPA has
sufficient data to assess the hazards of tebuconazole and to make a
determination on aggregate exposure, consistent with 408(b)(2), for
time-limited tolerances for residues of tebuconazole on barley grain at
2.0 ppm, barley hay at 20 ppm, barley straw at 20 ppm, wheat hay at 15
ppm, wheat straw at 2.0 ppm, pistachios at 1.0 ppm, milk at 0.1 ppm,
and meat byproducts of cattle, goats, hogs, horses, poultry and sheep
at 0.2 ppm. EPA's assessment of the dietary exposures and risks
associated with establishing these 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 population subgroup of concern for this acute dietary risk
assessment is females (13+ years).
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. The RfD of 0.03 mg/kg/day was established
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 (UP) of 100 was applied
to account for both interspecies and intraspecies 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. Aggregate Exposure
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 at levels ranging from 0.05 ppm in barley, oat
and wheat grain to 4.0 ppm in cherries and peanut hulls. Time-limited
tolerances for wheat commodities are based on residue data provided
with the section 18 submission; time-limited tolerances for barley
commodities are based on residue data submitted with tolerance petition
PP#9F3724; and the time-limited tolerance for pistachios is based on
residue data submitted with tolerance petition PP#3F4222. Time-limited
tolerances for the combined residues of tebuconazole and its 1-(4-
chlorophenyl)-4,4-dimethyl-3-(1H-1,2,4-triazole-1-yl-methyl)-pentane-
3,5-diol metabolite (HGW 2061) will be established to address potential
secondary residues of tebuconazole in milk and meat byproducts of
cattle, goats, hogs, horses, poultry and sheep.
For the purpose of assessing potential chronic dietary exposure
from tebuconazole, EPA assumed tolerance level residues and 100% of
crop treated to estimate the Theoretical Maximum Residue Contribution
(TMRC) for major identifiable subgroups of consumers,
[[Page 33554]]
including infants and children, from the proposed and existing food
uses of tebuconazole. These same assumptions were made in assessing
acute dietary exposure as well.
In examining aggregate exposure, FQPA directs EPA to consider
available information concerning exposures from the pesticide residue
in food and all other non-occupational exposures. The primary non-food
sources of exposure the Agency looks at include drinking water (whether
from groundwater or surface water), and exposure through pesticide use
in gardens, lawns, or buildings (residential and other indoor uses).
There are no groundwater data for tebuconazole available in OPP's
One-Liner Data Base. No Maximum Concentration Level and no Health
Advisory Level has been established for residues of tebuconazole in
drinking water.
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 exposure from tebuconazole to
exceed the RfD if the tolerance being considered in this document were
granted. 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.
Tebuconazole is not currently registered for indoor or outdoor
residential use. Thus, no non-dietary, non-occupational exposure is
expected.
C. Cumulative Exposure to Substances With Common Mechanism of Toxicity
Tebuconazole is a member of the triazole class of systemic
fungicides (The Pesticide Book, 4th ed., 1994). Other triazoles include
bitertanol, cyproconazole, diclobutrazole, difenoconazole,
diniconazole, fenbuconazole, flusilazole, hexaconazole, myclobutanil,
penconazole, propiconazole, tetraconazole, triadimefon, and triadimenol.
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 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.
D. 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 1,000. 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. 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 percent 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, 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.
E. Aggregate Risks and Determination of Safety for Infants and Children
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, rabbit, and mouse and a 2-
[[Page 33555]]
generation reproduction study in the rat. The developmental toxicity
studies are designed to evaluate adverse effects on the developing
organism resulting from pesticide exposure during prenatal development
to one or both parents. Reproduction studies provide information
relating to effects from exposure to the pesticide on the reproductive
capability of mating animals and data on systemic toxicity.
The pre- and post-natal toxicology data base for tebuconazole is
complete with respect to current toxicological data requirements. The
data base does not indicate a potential for increased sensitivity from
pre- and post-natal exposure.
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 developmental 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.
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.
FDCA 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 margin of exposure 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 margin of exposure and uncertainty factor (usually
100 for combined inter- and intra-species variability)) and not the
additional tenfold margin of exposure/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 margin of exposure/safety factor.
Neither the rat, rabbit, and mouse developmental studies nor the
rat reproduction study seem to demonstrate any special pre- or post-
natal sensitivity for infants and children, since the NOELs and LOELs
were the same for both parental and pup toxicity in all of these
studies. This demonstrates that developmental or reproductive toxicity
to pups occurs only in the presence of maternal effects. EPA therefore
concludes that reliable data support use of the standard hundredfold
uncertainty factor and that an additional safety factor is not needed
to protect infants and children.
1. Acute risk. The acute dietary MOE for females (13+ years), the
subpopulation of concern for developmental toxicity, is 1,000.
Generally, MOEs of greater than 100 are of no concern to the Agency.
Despite the potential for exposure to tebuconazole in drinking water,
EPA does not expect the aggregate exposure to infants or children to
exceed the level of concern for acute dietary exposure. EPA concludes
that there is a reasonable certainty that no harm will result to
infants and children from aggregate exposure to tebuconazole residues.
2. Chronic risk. Using the conservative exposure assumptions
described above, EPA has concluded that aggregate exposure to
tebuconazole from food will utilize 32% of the RfD for non-nursing
infants and 14% of the RfD for children 1 through 6 years old. EPA
generally has no concern for exposures below 100 percent 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, 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 chronic aggregate
exposure to tebuconazole residues.
V. Other Considerations
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). Adequate
enforcement methodology is available to enforce the tolerance
expressions. For the pistachio, barley and wheat tolerances, a gas
chromatographic method is available with the Agency, associated with
PP#9F3724; for the meat byproduct and milk tolerances, a gas
chromatographic method for determining residues of tebuconazole and its
metabolite HGW 2061 is available with the Agency, also associated with
PP#9F3724. Residues of tebuconazole per se are not expected to exceed
2.0 ppm in/on barley grain, 20 ppm in/on barley hay, 20 ppm in/on
barley straw, 15 ppm in/on wheat hay, 2.0 ppm in/on wheat straw, and
1.0 ppm in/on pistachios as a result of these section 18 uses. Combined
residues of tebuconazole and its metabolite HGW 2061 are not expected
to exceed 0.1 ppm in/on milk, and 0.2 ppm in/on meat byproducts of
cattle, goats, hogs, horses, poultry and sheep as a result of these
section 18 uses.
Codex maximum residue limits (MRLs) exist for residues of
tebuconazole per se in/on barley grain at 0.2 ppm; barley straw and dry
fodder at 10 ppm; wheat grain at 0.05 ppm; wheat straw and dry fodder
at 10 ppm; milk (cattle) at 0.01 ppm; cattle edible offal at 0.05 ppm;
and chicken edible offal at 0.05 ppm. These Codex MRLs are not in
harmony with those of the United States with respect to: (a) the
tolerance expression for animal commodities; (b) the definitions of the
tolerated commodities; and, (c) the tolerance levels. These disparities
can not be harmonized for purposes of these section 18 actions.
OPP suggests that, once permanent tolerances and section 3
registrations are established for the uses on barley and wheat, the
registrant consider providing all relevant studies to Codex in order
that Codex MRLs may be amended to accommodate U.S. use needs.
There is no Canadian MRL established for use of tebuconazole on
barley. There is a Mexican MRL of 0.2 ppm for residues of tebuconazole
per se in/on barley (grain); the use pattern of these section 18s does
not permit harmonization to that tolerance level.
[[Page 33556]]
There is a Canadian MRL established for tebuconazole on ``wheat
seed'' at 0.1 ppm. There is no Mexican MRL.
There are no Codex, Canadian or Mexican MRLs for residues of
tebuconazole in or on pistachios. International harmonization is not an
issue for this section 18 use.
VI. Conclusion
Therefore, tolerances in connection with the FIFRA section 18
emergency exemptions are established for residues of tebuconazole in or
on barley grain at 2.0 ppm, barley hay at 20 ppm, barley straw at 20
ppm, wheat hay at 15 ppm, wheat straw at 2.0 ppm, and pistachios at 1.0
ppm. Tolerances are established for the combined residues of
tebuconazole and its 1-(4-chlorophenyl)-4,4-dimethyl-3-(1H-1,2,4-
triazole-1-yl-methyl)-pentane-3,5-diol metabolite (HGW 2061) in milk at
0.1 ppm and in meat byproducts of cattle, goats, hogs, horses, poultry
and sheep at 0.2 ppm. These tolerances will expire and are revoked on
June 30, 1998.
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 August 19, 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
The official record for this rulemaking, as well as the public
version, has been established for this rulemaking under docket control
number [OPP-300506] (including comments and data submitted
electronically as described below). 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 official rulemaking record is located at the Virginia
address in ADDRESSES at the beginning of this document.
Electronic comments can 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. Comment and data
will also be accepted on disks in Wordperfect 5.1 file format or ASCII
file format. All comments and data in electronic form must be
identified by the docket control number [OPP-300506]. Electronic
comments on this rule may be filed online at many Federal Depository
Libraries.
IX. Regulatory Assessment Requirements
Under Executive Order 12866 (58 FR 51735, October 4, 1993), this
action is not a ``significant regulatory action'' and, since this
action does not impose any information collection requirements as
defined by the Paperwork Reduction Act, 44 U.S.C. 3501 et seq., it is
not subject to review by the Office of Management and Budget. In
addition, this action does not impose any enforceable duty or contain
any unfunded mandate as described in the Unfunded Mandates Reform Act
of 1995 (Pub. L. 104-4), or require prior consultation with State
officials as specified by Executive Order 12875 (58 FR 58093, October
28, 1993), or special considerations as required by Executive Order
12898 (59 FR 7629, February 16, 1994).
Because FFDCA section 408(l)(6) permits establishment of this
regulation without a notice of proposed rulemaking, the regulatory
flexibility analysis requirements of the Regulatory Flexibility Act, 5
U.S.C. 604(a), do not apply. Nonetheless, the Agency has previously
assessed whether establishing tolerances or exemptions from tolerance,
raising tolerance levels, or expanding exemptions adversely impact
small entities and concluded, as a generic matter, that there is no
adverse impact. (46 FR 24950) (May 4, 1981).
Under 5 U.S.C. 801(a)(1)(A) of the Small Business Regulatory
Enforcement Fairness Act of 1996 (Title II of Pub. L. 104-121, 110
Stat. 847), EPA 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 the rule in today's Federal Register.
This rule is not a ``major rule'' as defined by 5 U.S.C. 804(2).
List of Subjects in 40 CFR Part 180
Environmental protection, Administrative practice and procedure,
Agricultural commodities, Pesticides and pests, Reporting and
recordkeeping requirements.
Dated: June 9, 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. Section 180.474 is amended as follows:
i. The section heading is revised to read as set forth below.
[[Page 33557]]
ii. The existing text is designated as paragraph (a) ``General''.
iii. Paragraphs (b), (c), and (d) are added as follows:
Sec. 180.474 Tebuconazole; tolerances for residues.
(a) General. * * *
* * * * *
(b) Section 18 emergency exemptions--(1) Use on grains, hay and
other plant products. Time-limited tolerances are established for
residues of the fungicide tebuconazole (alpha-[2-(4-chlorophenyl)-
ethyl]-alpha-(1,1-dimethylethyl)-1H-1,2,4-triazole-1-ethanol) in
connection with use of the pesticide under section 18 emergency
exemptions granted by EPA. The tolerances will expire and are revoked
on the dates specified in the following table.
------------------------------------------------------------------------
Parts per Expiration/Revocation
Commodity million Date
------------------------------------------------------------------------
Barley, grain..................... 2.0 June 30, 1998
Barley, hay....................... 20.0 Do.
Barley, straw..................... 20.0 Do.
Pistachios........................ 1.0 Do.
Wheat, hay........................ 15.0 Do.
Wheat, straw...................... 2.0 Do.
------------------------------------------------------------------------
(2) Use on meat and meat byproducts. Time-limited tolerances are
established for the combined residues of the fungicide tebuconazole and
its 1-(4-chlorophenyl)-4,4-dimethyl-3-(1H-1,2,4-triazole-1-yl-methyl)-
pentane-3,5-diol metabolite (HGW 2061) in connection with use of the
pesticide under section 18 emergency exemptions granted by EPA. The
tolerances will expire and are revoked on the dates specified in the
following table.
------------------------------------------------------------------------
Parts per Expiration/Revocation
Commodity million Date
------------------------------------------------------------------------
Milk.............................. 0.1 June 30, 1998
Cattle, meat byproducts........... 0.2 Do.
Goats, meat byproducts............ 0.2 Do.
Hogs, meat byproducts............. 0.2 Do.
Horses, meat byproducts........... 0.2 Do.
Poultry, meat byproducts.......... 0.2 Do.
Sheep, meat byproducts............ 0.2 Do.
------------------------------------------------------------------------
(c) Tolerances with regional registrations. [Reserved]
(d) Indirect or inadvertent residues. [Reserved]
[FR Doc. 97-16216 Filed 6-19-97; 8:45 am]
BILLING CODE 6560-50-F