[Federal Register Volume 62, Number 175 (Wednesday, September 10, 1997)]
[Rules and Regulations]
[Pages 47561-47568]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-23975]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 180, 185 and 186

[OPP-300549; FRL-5743-6]
RIN 2070-AB78


Triadimefon; 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 triadimefon in or on asparagus and in or on artichokes. 
This action is in response to EPA's granting of an emergency exemption 
under section 18 of the Federal Insecticide, Fungicide, and Rodenticide 
Act authorizing use of the pesticide on asparagus and artichokes. This 
regulation establishes maximum permissible levels for residues of 
triadimefon 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. These tolerances will expire and are 
revoked on September 1, 1999.

DATES: This regulation is effective September 10, 1997. Objections and 
requests for hearings must be received by EPA on or before November 10, 
1997.

ADDRESSES: Written objections and hearing requests, identified by the 
docket control number, [OPP-300549], 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-300549], must also 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 may also be submitted electronically by sending electronic mail 
(e-mail) to: [email protected]. 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-300549]. 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: Olga Odiott, 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) 308-9363, e-mail: 
[email protected].

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 triadimefon, in or on asparagus at 0.15 part 
per million (ppm), and in or on artichokes at 0.6 ppm. These tolerances 
will expire and are revoked on September 1, 1999. 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 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.

[[Page 47562]]

II. Emergency Exemption for Triadimefon on Asparagus and Artichokes 
and FFDCA Tolerances

    The state of Michigan availed itself of the authority to declare a 
crisis exemption to use triadimefon to control the asparagus rust 
(Puccinia asparagi). EBDC fungicides are available and are effective 
against the asparagus rust but processors in Michigan will not accept 
asparagus treated with EBDCs, leaving the Michigan growers with no 
alternative for control of the disease. Yield declines of 20 to 50% are 
possible without the use of triadimefon.
     The state of California stated that powdery mildew, caused by the 
fungus Leveillula taurica Lev., is a relatively new disease of 
artichokes that was first detected by growers in California during the 
summer of 1985. It is now endemic in most artichoke growing districts, 
affecting more than 65% of the artichoke acreage. Currently, there are 
no registered fungicides or alternative practices available that will 
control powdery mildew on artichokes. If triadimefon is not available 
for use, yield losses of 30 to 50% are expected. EPA has authorized 
under FIFRA section 18 the use of triadimefon on asparagus and 
artichokes for control of rust in Michigan and powdery mildew in 
California. After having reviewed their submissions, EPA concurs that 
emergency conditions exist for these states.
    As part of its assessment of this emergency exemption, EPA assessed 
the potential risks presented by residues of triadimefon in or on 
asparagus and in or on artichokes. 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 the emergency exemption in order to address 
an urgent non-routine situation and to ensure that the resulting food 
is safe and lawful, EPA is issuing these tolerances without notice and 
opportunity for public comment under section 408(e), as provided in 
section 408(l)(6). Although these tolerances will expire and are 
revoked on September 1, 1999, under FFDCA section 408(l)(5), residues 
of the pesticide not in excess of the amounts specified in the 
tolerance remaining in or on asparagus and in or on artichokes 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 triadimefon 
meets EPA's registration requirements for use on asparagus and 
artichokes or whether permanent tolerances for these uses would be 
appropriate. Under these circumstances, EPA does not believe that these 
tolerances serves as a basis for registration of triadimefon 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 Michigan and 
California 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 the emergency 
exemption for triadimefon, 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 100-fold MOE is based on the same rationale as the 
100-fold 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 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.

[[Page 47563]]

    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 < 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 
this action, EPA has sufficient data to assess the hazards of 
triadimefon and to make a determination on aggregate exposure, 
consistent with section 408(b)(2), for a time-limited tolerances for 
residues of triadimefon in or on asparagus at 0.15 ppm and in or on 
artichokes at 0.6 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 triadimefon are 
discussed below. Triadimenol is a metabolite of triadimefon and is also 
an active ingredient in pesticide products (ex. Baytan). Toxicological 
endpoints for triadimefon and triadimenol are presented below.
    1. Acute toxicity. The NOEL of 20 mg/kg/day from a rabbit 
developmental study was selected for assessing acute dietary risk from 
residues of triadimefon. The risk assessment will evaluate acute 
dietary risks for females 13+ years old.
    The Agency has determined that an acute dietary risk assessment is 
not required for triadimenol. This decision was based on the lack of 
developmental effects at a maternally toxic dose of triadimenol in a 
rabbit developmental study.
     2. Short - and intermediate - term toxicity. The Agency determined 
that the NOEL of 20 mg/kg/day from the developmental toxicity study in 
rabbits should be used to assess risks from short and intermediate-term 
exposures to residues of triadimefon.
    The Agency determined that the NOEL of 250 mg/kg/day (highest dose 
tested) from a 21-day dermal toxicity study in rabbits should be used 
to assess risks from short- and intermediate-term exposures to residues 
of triadimenol.
    3. Chronic toxicity. EPA has established the RfD for triadimefon at 
0.04 milligrams/kilogram/day (mg/kg/day). This RfD is based on a 2-year 
dog feeding study. The NOEL for systemic toxicity in dogs of either sex 
was 11.4 mg/kg/day and the LOEL was 33.7 mg/kg/day based on decreased 
food intake, depression in weight gain, and significantly (p < 0.05) 
increased alkaline phosphatase activity in both sexes. An uncertainty 
factor (UF) of 300 was applied to account for inter-species 
extrapolation (10), intra-species variability (10) and the lack of an 
adequate reproductive toxicity study in rats (3).
    The RfD for triadimenol was established at 0.038 mg/kg/day. This 
RfD is based on 2-year and 6-month

[[Page 47564]]

feeding studies in dogs with a NOEL of 3.75 mg/kg/day and an 
uncertainty factor of 100 based on changes in enzyme levels at the LOEL 
of 15.0 mg/kg/day.
    4. Carcinogenicity. The Agency's Carcinogenicity Peer Review 
Committee (CPRC) has classified triadimefon as a Group C (possible 
human carcinogen) chemical without a Q1* and recommended 
using the RfD approach to assess dietary cancer risk. The 
classification was based on an increase in thyroid adenomas in male 
rats and an increase in hepatocellular adenomas, with a positive dose-
related trend, in both male and female mice.
    The CPRC classified triadimenol as a Group C (possible human 
carcinogen) chemical based on liver tumors in female mice. The 
Committee recommended using the RfD approach to assess dietary cancer 
risk.

B. Exposures and Risks

    1. From food and feed uses. Tolerances have been established (40 
CFR 180.410) for the combined residues of triadimefon and its 
metabolites containing chlorophenoxy and triazole moieties (expressed 
as triadimefon), in or on a variety of raw agricultural commodities 
ranging from 0.04 ppm in poultry meat to 145 ppm in grass seed 
cleanings.
    Tolerances have been established (40 CFR 180.450(a)) for the 
combined residues of the fungicide triadimenol (KWG-0519,-(4-
chlorophenoxy)--(1,1-dimethylethyl)-1H-1,2,4-triazol-1-
ethanol) and its butanediol metabolite (KWG-1342; 4-(4-chlorophenoxy)-
2,2-dimethyl-4-(1H-1,2,4-triazol-1-yl)-1,3-butanediol), calculated as 
triadimenol, in or on various commodities including barley, oats and 
wheat grain at 0.05 ppm; barley, oats and wheat forage at 2.5 ppm; and 
barley, oats and wheat straw at 0.1 ppm. Tolerances have been 
established (40 CFR 180.450(b)) for the combined residues of 
triadimenol and its metabolites containing the chlorophenoxy moiety 
(calculated as triadimenol) in or on the fat, meat, and meat by-
products of cattle, goats, hogs, horses and sheep at 0.1 ppm; milk at 
0.01 ppm; the fat, meat, and meat by-products of poultry at 0.01 ppm; 
and eggs at 0.01 ppm. Risk assessments were conducted by EPA to assess 
dietary exposures and risks from triadimefon and triadimenol as 
follows:
    i.  Acute exposure and risk. Acute dietary risk assessments are 
performed for a food-use pesticide if a toxicological study has 
indicated the possibility of an effect of concern occurring as a result 
of a 1-day or single exposure. The acute dietary (food only) risk 
assessment for triadimefon used tolerance level residues and assumed 
100% crop treated. For the population subgroup of concern, females 13+ 
years old, the resulting high-end exposure estimate of 0.05 mg/kg/day 
results in a dietary (food only) MOE of 400. This MOE should be viewed 
as a conservative risk estimate. Refinement of the risk assessment 
using anticipated residue values and percent crop-treated data would 
result in a lower acute dietary exposure estimate.
    Acute dietary endpoints were not identified for triadimenol, so 
this risk assessment was not conducted.
    ii. Chronic exposure and risk. The chronic dietary risk assessment 
for triadimefon assumed that 100% of asparagus and artichokes and all 
other commodities having established and pending triadimefon tolerances 
will contain triadimefon residues and those residues will be at 
tolerance level, which result in an overestimate of human dietary 
exposure. The existing triadimefon tolerances (published, pending, and 
including the necessary Section 18 tolerances) result in a TMRC that is 
equivalent to percentages of the RfD that range from 18% for the U.S. 
population to 75% for non-nursing infants < 1 year old.
    The chronic dietary risk assessment for triadimenol assumed that 
all commodities having established and pending triadimenol tolerances 
will contain triadimenol residues and those residues will be at the 
level of the tolerance, which result in an overestimate of human 
dietary exposure. Thus, in making a safety determination for 
triadimenol, EPA is taking into account this conservative exposure 
assessment. The existing triadimenol tolerances (published and pending) 
result in a TMRC that is equivalent to percentages of the RfD that 
range from 1% for the U.S. population to 3% for non-nursing infants < 1 
year old.
    2. From drinking water. Based on available data used in EPA's 
assessment of environmental risk, triadimefon and triadimenol are 
mobile and have the potential to leach into ground water. There are no 
established Maximum Contaminant Levels for residues of triadimefon or 
triadimenol in drinking water, and no Health Advisory levels for 
triadimefon or triadimenol in drinking water have been established. 
According to the ``Pesticides in Groundwater Database'', EPA 734-12-92-
001, Sept 1992, 14 wells in California were sampled for triadimefon 
from 1984-1989. No wells had detectable residues. There was no entry 
for triadimenol.
    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 triadimefon and triadimenol to 
exceed the RfD if the tolerances being considered in this document were 
granted. The Agency has therefore concluded that the potential 
exposures associated with triadimefon and triadimenol 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 tolerances are granted.
    3. From non-dietary exposure. Triadimefon is currently registered 
for use on non-food sites such as ornamentals and turfgrass. 
Triadimenol is currently registered for use on turfgrass. Based on the 
nature of the outdoor residential uses, the EPA concludes that chronic 
residential exposure scenarios do not exist for triadimefon. Short and/
or intermediate term exposure scenarios may exist. However, the Agency 
currently lacks sufficient residential-related exposure data to 
complete a comprehensive residential risk assessment for many 
pesticides, including triadimefon.
    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

[[Page 47565]]

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).
    Triadimefon and triadimenol are members of the triazole class of 
pesticides. Other members of this class include tebuconazole, 
propiconazole, cyproconazole, penconazole, myclobutanil, and 
difenoconazole. At this time, the Agency has not made a determination 
that triadimefon and other substances that may have a common mode of 
toxicity would have cumulative effects, with the exception of 
triadimenol. A regulated metabolite of triadimefon, triadimenol is 
itself a fungicide active ingredient registered for use on several 
crops. In plants, the residue of concern for triadimenol is triadimenol 
and its butanediol metabolite. In animal commodities, the residue of 
concern for triadimenol is triadimenol and its metabolites containing 
the chlorophenoxy moiety.
    To estimate the cumulative (triadimefon + triadimenol) aggregate 
dietary exposures, estimates for triadimenol on its regulated 
commodities were added to estimates for triadimefon.

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

    1. Acute risk. For the population subgroup of concern, females 13+ 
years, the calculated MOE value for triadimefon dietary (food) exposure 
is 400. Although there is potential for exposure to triadimefon in 
drinking water, the Agency does not expect the aggregate exposure (food 
plus water) to exceed the Agency's level of concern.
    No acute toxicity endpoints were identified for triadimenol, 
therefore an acute aggregate risk assessment was not conducted.
    2. Chronic risk. Using the TMRC exposure assumptions described 
above, EPA has concluded that aggregate exposure to triadimefon and 
triadimenol from food will utilize 19% of the RfD for the U.S. 
population. The major identifiable subgroup with the highest aggregate 
exposure is non-nursing infants < 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 exposure over a 
lifetime will not pose appreciable risks to human health. Despite the 
potential for exposure to triadimefon and triadimenol 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 triadimefon and triadimenol residues.
    3. Short- and intermediate-term risk. Short- and intermediate-term 
aggregate exposure takes into account chronic dietary food and water 
(considered to be a background exposure level) plus indoor and outdoor 
residential exposure.
    Based on the registered uses of fenarimol short and/or intermediate 
term exposure scenarios may exist. However, the Agency currently lacks 
sufficient residential-related exposure data to complete a 
comprehensive residential risk assessment for many pesticides, 
including triadimefon.

D. Aggregate Cancer Risk for U.S. Population

    The Agency's CPRC recommended the RfD approach for assessment of 
dietary cancer risk. Dietary risk concerns due to long-term exposures 
to triadimefon and triadimenol residues are adequately addressed by the 
aggregate chronic dietary risk assessment.

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 triadimefon and triadimenol, 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 (for combined inter- and intra-species variability) 
and not the additional tenfold safety 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-- a. Rats. For triadimefon, the 
maternal systemic NOEL was 30 mg/kg/day and the LOEL was 90 mg/kg/day. 
Effects seen at the LOEL include statistically significant body weight 
gain decrement during gestational days 6-15. The developmental NOEL was 
30 mg/kg/day and the developmental LOEL was 90 mg/kg/day, based on the 
increased incidence of skeletal variations, unossified and incompletely 
ossified hyoid, and full and rudimentary ribs.
    For triadimenol, the maternal (systemic) NOEL was 25 mg/kg/day, 
based on decreased body weight and food consumption at the LOEL of 125 
mg/kg/day. The developmental (fetal) NOEL was 125 mg/kg/day (highest 
dose tested (HDT)).

[[Page 47566]]

    b. Rabbits. For triadimefon, the maternal (systemic) NOEL was 50 
mg/kg/day and the LOEL was 120 mg/kg/day. The maternal LOEL was based 
on increased clinical signs such as increased hyperactivity, reddish 
discharge, and decreased body weight gain during gestational days 6-10. 
The developmental NOEL was 20 mg/kg/day and the LOEL was 50 mg/kg/day, 
based on irregular spinous process and incomplete ossification of 
various bones.
    For triadimenol, the maternal (systemic) NOEL was 8 mg/kg/day, 
based on decreased body weight and food consumption at the LOEL of 40 
mg/kg/day. The developmental (fetal) NOEL was 40 mg/kg/day, based on 
post-implantation loss, decreased fetal body weight, and skeletal 
anomalies at the LOEL of 200 mg/kg/day.
    iii. Reproductive toxicity study. An acceptable reproductive 
toxicity study is not available for triadimefon.
    For triadimenol, the maternal (systemic) NOEL from a 2-generation 
reproductive toxicity study in rats was 5.0 mg/kg/day. The NOEL was 
based on decreased body weight at the LOEL of 25 mg/kg/day. The 
developmental (pup) NOEL was 5.0 mg/kg/day, based on decreased body 
weight at the LOEL of 25 mg/kg/day. The reproductive NOEL was 25 mg/kg/
day (HDT).
    iv. Pre- and post-natal sensitivity. The toxicological data base 
for evaluating pre- and post-natal toxicity for triadimefon is not 
complete with respect to current data requirements. However, in 
calculating the RfD, an uncertainty factor (UF) of 300 was applied to 
account for inter-species extrapolation (10), intra-species variability 
(10), and the lack of an adequate reproductive toxicity study in rats 
(3). The Agency notes that there is approximately a two-fold difference 
between the developmental NOEL of 20 mg/kg/day from the rabbit 
developmental toxicity study and the NOEL of 11.4 mg/kg/day from the 2-
year dog feeding study which was the basis of the RfD. It is further 
noted that in the rabbit developmental toxicity study, the 
developmental NOEL of 20 mg/kg/day (on which the MOE calculations for 
acute dietary risks are based) is lower than the maternal systemic NOEL 
of 50 mg/kg/day from the same rabbit developmental study. The Agency 
believes that the additional 3X uncertainty factor, together with the 
very conservative assumptions made for the exposure assessment, provide 
adequate protection to infants and children from the risks associated 
with exposures to triadimefon residues.
    The toxicological data base for evaluating pre- and post-natal 
toxicity for triadimenol is complete with respect to current data 
requirements. There are no pre- or post-natal toxicity concerns for 
infants and children, based on the results of the rat and rabbit 
developmental toxicity studies and the 2-generation rat reproductive 
toxicity study. The rat developmental study had no developmental 
effects up to the highest dose tested, which produced maternal 
toxicity. The rabbit developmental toxicity study demonstrated maternal 
toxicity at a dose at which no developmental toxicity was apparent. In 
the rat reproductive toxicity study, the parental and pup effects occur 
at the NOELs and LOELs and the same effect (decreased body weight) 
occurred in both pups and parental animals.
    v. Conclusion. Based on the above considerations and in EPA's best 
scientific judgment, the application of a margin of exposure/
uncertainty factor of 300 provides adequate protection for infants and 
children from the risks associated with exposures to triadimefon 
residues.
    The EPA also concludes that, for triadimenol, reliable data support 
use of the standard 100-fold margin of exposure/ uncertainty factor and 
that an additional margin/factor is not needed to protect infants and 
children.
    2. Acute risk. For triadimefon, the acute dietary (food only) MOE 
was calculated to be 400 for females 13+ years old (accounts for both 
maternal and fetal exposure), the population subgroup of concern. This 
risk assessment for triadimefon used tolerance level residues and 
assumed 100% crop treated. This MOE should be viewed as a conservative 
risk estimate; further refinement using anticipated residue values and 
percent crop-treated data would result in a lower acute dietary 
exposure estimate. The large acute dietary MOE calculated for females 
13+ years provides assurance that there is a reasonable certainty of no 
harm for both females 13+ years and the pre-natal development of 
infants. Despite the potential for exposure to triadimefon in drinking 
water, the Agency does not expect the aggregate exposure (food + water) 
to exceed the Agency's level of concern for acute dietary exposure.
    No acute toxicity endpoints were identified for triadimenol, so an 
acute aggregate risk assesment was not conducted.
    3. Chronic risk. Using the conservative exposure assumptions 
described above, EPA has concluded that aggregate exposure to 
triadimefon and triadimenol from food will utilize percentages of the 
RfD that range from 28% for children 7-12 years old, up to 78% for non-
nursing infants less than 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 exposure over a lifetime will 
not pose appreciable risks to human health. Despite the potential for 
exposure to triadimefon and triadimenol 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 triadimefon and triadimenol residues.
    4. Short- or intermediate-term risk. Based on the registered uses 
of fenarimol short and/or intermediate term exposure scenarios may 
exist. However, the Agency currently lacks sufficient residential-
related exposure data to complete a comprehensive residential risk 
assessment for many pesticides.

V. Other Considerations

A. Metabolism In Plants and Animals

    The nature of triadimefon residues in plants is adequately 
understood. The Agency's Metabolism Committee determined that the 
residues of concern are triadimefon and its metabolites containing 
chlorophenoxy and triazole moieties, expressed as triadimefon. The 
nature of triadimefon residues in animals is not germane to these 
tolerances as no livestock feed items are involved.

B. Analytical Enforcement Methodology

    Adequate enforcement methods (GC/MS) are published in the Pesticide 
Analytical Manual, Volume II, Pesticide Reg. Sec. 180.410, as Methods I 
and II. In addition, Mobay Method No. 80488 has undergone a successful 
method trial and has been validated for determination of triadimefon 
and its metabolites relevant to 40 CFR 180.410 on plant commodities.

C. Magnitude of Residues

    Regulable residues of triadimefon are not expected to exceed 0.15 
ppm in/on asparagus and 0.6 ppm in/on globe artichokes as a result of 
these section 18 uses. Secondary residues are not expected in animal 
commodities as no feed items are associated with these section 18 uses.

D. International Residue Limits

    There are no CODEX, Canadian, or Mexican maximum residue limits 
(MRLs) established for residues of

[[Page 47567]]

triadimefon in/on asparagus or in/on artichokes.

VI. Conclusion

    Therefore, time-limited tolerances are established for the 
regulable residues of triadimefon in asparagus at 0.15 ppm and in 
artichokes at 0.6 ppm. In addition, because the FQPA eliminated the 
distinctions between processed food, feed and raw agricultural 
commodities, OPP is transferring the tolerances for residues of 
triadimefon in Secs. 185.800 and 186.800 to the table in paragraph (a) 
of Sec. 180.410 and removing the remainder of Secs. 185.800 and 
186.800.

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 November 10, 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 
Confidential Business Information (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-300549] (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 (7506C), 
Office of Pesticide Programs, Environmental Protection Agency, Crystal 
Mall #2, 1921 Jefferson Davis Highway, Arlington, VA.
    Electronic comments may be sent directly to EPA at:
    [email protected].


    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(d l)(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 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(l)(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 acations 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).

[[Page 47568]]

List of Subjects

40 CFR Part 180

    Environmental protection, Administrative practice and procedure, 
Agricultural commodities, Pesticides and pests, Reporting and 
recordkeeping requirements.

40 CFR Part 185

    Environmental protection, Food additives, Pesticides and pests.

40 CFR Part 186

    Environmental protection, Animal feeds, Pesticides and pests.

    Dated: August 29, 1997.

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

PART 180--[AMENDED]

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

    Authority: 21 U.S.C. 346a and 371.


    b. By amending Sec. 180.410 as follows:
    i. By revising the section heading.
    ii. By adding a subject heading to paragraph (a).
    iii. By revising paragraphs (b) and (c).
    iv. By adding and reserving paragraph (d) with a subject heading.


Sec. 180.410   Triadimefon; tolerances for residues.

    (a) General . *      *      *
    (b) Section 18 emergency exemptions. Time-limited tolerances are 
established for the combined residues of the fungicide triadimefon, 1-
(4-chlorophenoxy)-3,3-dimethyl-1(1H-1,2,4-triazol-1-yl)-2-butanone and 
its metabolites containing chlorophenoxy and triazole moieties 
(expressed as the fungicide) in connection with use of the pesticide 
under the section 18 emergency exemptions granted by EPA. The 
tolerances will expire and are revoked on the dates specified in the 
following table:

------------------------------------------------------------------------
                                        Parts                           
              Commodity                  per      Expiration/revocation 
                                       million            date          
------------------------------------------------------------------------
Artichokes...........................    0.6    September 1, 1999       
Asparagus............................    0.15   September 1, 1999       
Chili peppers........................    0.5    November 8, 1997        
------------------------------------------------------------------------

    (c)  Tolerances with regional registrations. Tolerances with 
regional registration are established for the combined residues of the 
fungicide 1-(4-chlorophenoxy)-3,3-dimethyl-1(1H-1,2,4-triazol-l-yl)-2-
butanone and its metabolites containing chlorophenoxy and triazole 
moieties (expressed as the fungicide) in or on the following raw 
agricultural commodities:

------------------------------------------------------------------------
                                                                  Parts 
                           Commodity                               per  
                                                                 million
------------------------------------------------------------------------
Raspberries...................................................       2.0
------------------------------------------------------------------------

    (d) Indirect or inadvertent residues. [Reserved]

PART 185--[AMENDED]

    2. In part 185:
    a. The authority citation for part 185 continues to read as 
follows:
    Authority: 21 U.S.C. 346a and 348.

Sec. 185.800 [Removed]

    b. In Sec. 185.800 by transferring the entries in the table and 
alphabetically adding them to the table in paragraph (a) of 
Sec. 180.410, and by removing the remainder of Sec. 185.800.

PART 186--[AMENDED]

    3. In part 186:
    a. The authority citation for part 185 continues to read as 
follows:
    Authority: 21 U.S.C. 342, 348, and 701.

Sec. 186.800 [Removed]

    b. In Sec. 186.800 by transferring the entries in the table and 
alphabetically adding them to the table in paragraph (a) of 
Sec. 180.410, and by removing the remainder of Sec. 186.800.
[FR Doc. 97-23975 Filed 9-9-97; 8:45 am]
BILLING CODE 6560-50-F