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carfentrazone-ethyl Temporary Pesticide Tolerance 7/98


[Federal Register: August 7, 1998 (Volume 63, Number 152)]
[Rules and Regulations]               
[Page 42240-42246]
>From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr07au98-25]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 180

[OPP-300686; FRL-6018-1]
RIN 2070-AB78

 
Carfentrazone-ethyl; Temporary Pesticide Tolerance

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: This regulation extends a temporary tolerance for combined 
residues of the herbicide carfentrazone-ethyl (fluorobenzenepropanoic 
acid) in or on wheat raw agricultural commodities: 0.2 ppm in or on 
wheat hay, 0.2 ppm in or on wheat straw, 0.2 ppm in or on wheat grain; 
and establishing tolerance for combined residues of the herbicide 
carfentrazone-ethyl (ethyl-alpha-2-dichloro-5-[4-(difluoromethyl)-4,5-
dihydro-3-methyl-5-oxo-1H-1,2,4-triazol-1-yl]-4-fluorobenzene-
propanoate) and its two major corn metabolites: carfentrazone-ethyl 
chloropropionic acid (alpha, 2-dichloro-5-[4-difluoromethyl)-4,5-
dihydro-3-methyl-5-oxo-1H-1,2,4-triazol-1-yl]-4-fluorobenzenepropanoic 
acid), and 3-desmethyl-FF8426 chloropropionic acid (alpha,2-dichloro-5-
[4-difluromethyl)-4,5-dihydro-5-oxo-1H-1,2,4-triazol-1-yl]-4-
fluorobenzenepropanoic acid) in or on corn raw agricultural 
commodities:; 0.15 ppm in or on corn forage, 0.15 ppm in or on corn 
fodder, 0.15 ppm in or on corn grain. FMC requested this tolerance 
under the Federal Food, Drug, and Cosmetic Act, as amended by the Food 
Quality Protection Act of 1966 (Pub. L. 104-170). The tolerance will 
expire on May 8, 1999.

DATES: This regulation is effective August 7, 1998. Objections and 
requests for hearings must be received by EPA on or before October 6, 
1998.
ADDRESSES: Written objections and hearing requests, identified by the 
docket control number, [OPP-300686], 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-300686], must also be submitted to: Public 
Information and Records Integrity Branch, Information Resources and 
Services Division (7502C), Office of Pesticide Programs, Environmental 
Protection Agency, 401 M St., SW., Washington, DC 20460. In person, 
bring a copy of objections and hearing requests to Rm. 119, CM #2, 1921 
Jefferson Davis Hwy., Arlington, VA.
    A copy of objections and hearing requests filed with the Hearing 
Clerk may also be submitted electronically by sending electronic mail 
(e-mail) to: opp-docket@epamail.epa.gov. Copies of objections and 
hearing requests must be submitted as an ASCII file avoiding the use of 
special characters and any form of encryption. Copies of objections and 
hearing requests will also be accepted on disks in WordPerfect 5.1/6.1 
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-300686]. 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: Joanne I. Miller, Product 
Manager PM-23, 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) 305-
6224, e-mail: miller.joanne@epamail.epa.gov.

SUPPLEMENTARY INFORMATION: In the Federal Register of June 10, 1998 (63 
FR 31769) (FRL-5793-1), EPA, issued a notice pursuant to section 408 of 
the Federal Food, Drug, and Cosmetic Act (FFDCA), 21 U.S.C. 346a(e) 
announcing the filing of a pesticide petition (PP 6G4615) for a 
tolerance by FMC Corporation, 1735 Market St., Philadelphia, PA 19103. 
This notice included a summary of the petition prepared by FMC 
Corporation, the registrant. There were no comments received in 
response to the notice of filing.
    The petition requested that 40 CFR part 180 be amended by extending 
a temporary tolerance for combined residues of the herbicide 
carfentrazone-ethyl (ethyl-alpha-2-dichloro-5-[4-(difluoromethyl)-4,5-
dihydro-3-methyl-5-oxo-1H-1,2,4-triazol-1-yl]-4-fluorobenzene-
propanoate), and its metabolite, in or on field corn forage, fodder, 
and grain at 0.15 parts per million (ppm); and for wheat hay, straw,

[[Page 42241]]

and grain at 0.2 ppm. This tolerance will expire on May 8, 1999.
    This tolerance request was submitted in a transmittal letter, dated 
April 29, 1998, along with an application for an experimiental use 
permit (EUP). This EUP proposes the experimental use of carfentrazone-
ethyl on corn and wheat. Under FIFRA, section 516C for experimental use 
permits, a temporary tolerance level must be established if a pesticide 
may reasonably be expected to result in any residue on or in food or 
feed use.

I. Risk Assessment and Statutory Findings

    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 specialconsideration 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. . . .''
    EPA performs a number of analyses to determine the risks from 
aggregate exposure to pesticide residues. First, EPA determines the 
toxicity of pesticides based primarily on toxicological studies using 
laboratory animals. These studies address many adverse health effects, 
including (but not limited to) reproductive effects, developmental 
toxicity, toxicity to the nervous system, and carcinogenicity. Second, 
EPA examines exposure to the pesticide through the diet (e.g., food and 
drinking water) and through exposures that occur as a result of 
pesticide use in residential settings.

A. Toxicity

    1. Threshold and non-threshold effects. For many animal studies, a 
dose response relationship can be determined, which provides a dose 
that causes adverse effects (threshold effects) and doses causing no 
observed effects (the ``no-observed effect level'' or ``NOEL'').
    Once a study has been evaluated and the observed effects have been 
determined to be threshold effects, EPA generally divides the NOEL from 
the study with the lowest NOEL by an uncertainty factor (usually 100 or 
more) to determine the Reference Dose (RfD). The RfD is a level at or 
below which daily aggregate exposure over a lifetime will not pose 
appreciable risks to human health. An uncertainty factor (sometimes 
called a ``safety factor'') of 100 is commonly used since it is assumed 
that people may be up to 10 times more sensitive to pesticides than the 
test animals, and that one person or subgroup of the population (such 
as infants and children) could be up to 10 times more sensitive to a 
pesticide than another. In addition, EPA assesses the potential risks 
to infants and children based on the weight of the evidence of the 
toxicology studies and determines whether an additional uncertainty 
factor is warranted. Thus, an aggregate daily exposure to a pesticide 
residue at or below the RfD (expressed as 100% or less of the RfD) is 
generally considered acceptable by EPA. EPA generally uses the RfD to 
evaluate the chronic risks posed by pesticide exposure. For shorter 
term risks, EPA calculates a margin of exposure (MOE) by dividing the 
estimated human exposure into the NOEL from the appropriate animal 
study. Commonly, EPA finds MOEs lower than 100 to be unacceptable. This 
100-fold MOE is based on the same rationale as the 100-fold uncertainty 
factor.
    Lifetime feeding studies in two species of laboratory animals are 
conducted to screen pesticides for cancer effects. When evidence of 
increased cancer is noted in these studies, the Agency conducts a 
weight of the evidence review of all relevant toxicological data 
including short-term and mutagenicity studies and structure activity 
relationship. Once a pesticide has been classified as a potential human 
carcinogen, different types of risk assessments (e.g., linear low dose 
extrapolations or MOE calculation based on the appropriate NOEL) will 
be carried out based on the nature of the carcinogenic response and the 
Agency's knowledge of its mode of action.
    2. Differences in toxic effect due to exposure duration. The 
toxicological effects of a pesticide can vary with different exposure 
durations. EPA considers the entire toxicity data base, and based on 
the effects seen for different durations and routes of exposure, 
determines which risk assessments should be done to assure that the 
public is adequately protected from any pesticide exposure scenario. 
Both short and long durations of exposure are always considered. 
Typically, risk assessments include ``acute,'' ``short-term,'' 
``intermediate term,'' and ``chronic'' risks. These assessments are 
defined by the Agency as follows.
    Acute risk, by the Agency's definition, results from 1-day 
consumption of food and water, and reflects toxicity which could be 
expressed following a single oral exposure to the pesticide residues. 
High end exposure to food and water residues are typically assumed.
    Short-term risk results from exposure to the pesticide for a period 
of 1-7 days, and therefore overlaps with the acute risk assessment. 
Historically, this risk assessment was intended to address primarily 
dermal and inhalation exposure which could result, for example, from 
residential pesticide applications. However, since enaction of FQPA, 
this assessment has been expanded to include both dietary and non-
dietary sources of exposure, and will typically consider exposure from 
food, water, and residential uses when reliable data are available. In 
this assessment, risks from average food and water exposure, and high-
end residential exposure, are aggregated. High-end exposures from all 
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 1-7 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

[[Page 42242]]

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.

II. 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 
carfentrazone-ethyl and to make a determination on aggregate exposure, 
consistent with section 408(b)(2), for a temporary tolerance for 
combined residues of carfentrazone-ethyl (ethyl-alpha-2-dichloro-5-[4-
(difluoromethyl)-4,5-dihydro-3-methyl-5-oxo-1H-1,2,4-triazol-1-yl]-4-
fluorobenzene-propanoate) and its metabolites on wheat at 0.2 ppm and 
corn at 0.15 ppm. EPA's assessment of the dietary exposures and risks 
associated with establishing the tolerance 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 carfentrazone-ethyl 
are discussed below.
    1. A battery of acute toxicity studies placed technical 
carfentrazone in Toxicity Categories III and IV. No evidence of 
sensitization was observed following dermal application in guinea pigs.
    2. A 90-day subchronic toxicity study was conducted in rats, with 
dietary intake levels of 58, 226, 4,700, 831 and 1,197 milligrams/
kilogram/day (mg/kg/day) in males and 72, 284, 578, 1,008 and 1,427 mg/
kg/day in females, respectively. A NOEL of 226 mg/kg/day (males) and 
5,778 mg/kg/day (females) was established. Lowest observed effect 
levels (LOELs) of 470 mg/kg/day (males) and 578 mg/kg/day (females) was 
established based on decreases in body weights and/or gains, reductions 
in food consumption, alterations in clinical chemistry parameters, and 
histopathological lesions.
    3. A reverse gene mutation assay (salmonella typhirmurium) yielded 
negative results, both with and without metabolic activation.
    4. An in vitro mutation assay test yielded negative results, there 
was no indication of an increased incidence of gene mutation at the 
HGPRT locus as a result of exposure.
    5. An in vitro mammalian cytogenetic test yielded positive under 
nonactivated conditions in this assay.
    6. An in vivo micronucleus cytogenetic assay study was conducted in 
mice by IP injection of 600, 1,200 and 2,400 mg/kg to groups of 5 males 
and 5 females. There was no indication of an increased incidence in 
micronucleated polychromatic erythrocytes associated with exposure to 
the test material.
    7. A 13-week study was conducted on 4 pure breed Beagle dogs/sex/
group for 90 days at dietary intake levels of 0, 50, 150, 500 and 1,000 
mg/kg/day. NOELs of 500 mg/kg/day for both sexes and the LOEL of 150 
mg/kg/day, based on systemic toxicity (decrease in the rate of weight 
gain in females and an increase in porphyrin levels in both sexes).
    8. An oral prenatal developmental study was administered by gavage 
to pregnant female New Zealand white rabbits (20/group) on days 7-19 of 
gestation at dose levels of 0, 10, 40, 150, or 300 mg/kg/day. There was 
no evidence of treatment-related prenatal developmental toxicity. The 
developmental LOEL was not determined. The developmental NOEL (greater 
or equal to sign) of 300 mg/kg/day.

B. Toxicological Endpoints

    1. Acute toxicity. The Agency does not have a concern for an acute 
dietary assessment since the available data do not indicate any 
evidence of significant toxicity from a one day or single event 
exposure by the oral route, therefore an acute (food and water) risk 
assessment was not required.
    2. Chronic toxicity. EPA has established the RfD for carfentrazone-
ethyl at 0.06 mg/kg/day. This RfD is based on the NOEL of 60 mg/kg/day 
from a 90-day rat study with a 1,000 fold uncertainty factor.
    3. Carcinogenicity. No concern for cancer risks were identified. 
Data from available studies do not indicate a treatment-related tumor 
problem, and cancer risk endpoints have not been identified.

C. Exposures and Risks

    1. From food and feed uses. Tolerances have not yet been 
established (40 CFR 180 ) for the combined residues of carfentrazone-
ethyl (ethyl-alpha-2-dichloro-5-[4-(difluoromethyl)-4,5-dihydro-3-
methyl-5-oxo-1H-1,2,4-triazol-1-yl]-4-fluorobenzene-propanoate), and 
its metabolites, in or on a variety of raw agricultural commodities. 
Due to the non-quantifiable carfentrazone-ethyl residues in/on the 
treated RAC's (except wheat forage, however, there is a label feeding 
restriction) fed to livestock and the limited number of acres involved, 
there is no expectation of secondary

[[Page 42243]]

residues in livestock commodities of meat, meat-by-products, fat, milk, 
and eggs. Risk assessments were conducted by EPA to assess dietary 
exposures and risks from carfentrazone-ethyl as follows:
    i.  Acute exposure and risk. Acute dietary risk assessments are 
performed for a food-use pesticide if a toxicological study has 
indicated the possibility of an effect of concern occurring as a result 
of a one day or single exposure. No short - and intermediate endpoints 
for occupational and residential exposure were identified.
    ii. Chronic exposure and risk. The chronic dietary analysis 
indicates that exposure from the proposed temporary tolerances for use 
of carfentrazone-ethyl in/on corn and wheat for the U.S. population 
would account for less than 1% of the RfD. For children (1-6 years), 
the subgroup with the highest exposure, 1% of the RfD would be 
utilized.
    This chronic analysis for carfentrazone is an upper-bound estimate 
of dietary exposure with all residues at tolerance level and assuming 
100% of the commodities to be treated. Since only 4,000 acres of wheat 
and 4,000 acres of corn will be treated under this EUP program which 
represents less than 1% of the total wheat and corn harvested in the 
United States, this dietary analysis represents an over estimate of the 
percent RfD that will be utilized by the proposed temporary tolerances. 
Therefore, the chronic dietary risk resulting from the proposed 
temporary tolerances for carfentrazone-ethyl will not exceed the 
Agency's level of concern.
    2. From drinking water. A chronic dietary risk assessment from 
drinking water was not conducted because of the short duration of the 
EUP (2 years) and the small percentage of treated acres for corn and 
wheat as a result of the proposed use (<1% of the total U.S. production 
for both commodities).
    3. Acute exposure and risk. As part of the hazard assessment 
process, the Agency reviews the available toxicological database to 
determine the endpoints of concern for acute dietary risk. There is no 
concern since the available data do not indicate any evidence of 
significant toxicity from a one day or single event exposure by the 
oral route. Therefore an acute dietary risk assessment was not 
required.
    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 carfentrazone-ethyl 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 carfentrazone-ethyl 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.
    4. From non-dietary exposure. The proposed uses for this pesticide 
does not include uses that would result in a non-dietary, non-
occupational exposure.
    5. Cumulative exposure to substances with common mechanism of 
toxicity. Section 408(b)(2)(D)(v) requires that, when considering 
whether to establish, modify, or revoke a tolerance, the Agency 
consider ``available information'' concerning the cumulative effects of 
a particular pesticide's residues and ``other substances that have a 
common mechanism of toxicity.'' The Agency believes that ``available 
information'' in this context might include not only toxicity, 
chemistry, and exposure data, but also scientific policies and 
methodologies for understanding common mechanisms of toxicity and 
conducting cumulative risk assessments. For most pesticides, although 
the Agency has some information in its files that may turn out to be 
helpful in eventually determining whether a pesticide shares a common 
mechanism of toxicity with any other substances, EPA does not at this 
time have the methodologies to resolve the complex scientific issues 
concerning common mechanism of toxicity in a meaningful way. EPA has 
begun a pilot process to study this issue further through the 
examination of particular classes of pesticides. The Agency hopes that 
the results of this pilot process will increase the Agency's scientific 
understanding of this question such that EPA will be able to develop 
and apply scientific principles for better determining which chemicals 
have a common mechanism of toxicity and evaluating the cumulative 
effects of such chemicals. The Agency anticipates, however, that even 
as its understanding of the science of common mechanisms increases, 
decisions on specific classes of chemicals will be heavily dependent on 
chemical specific data, much of which may not be presently available.
    Although at present the Agency does not know how to apply the 
information in its files concerning common mechanism issues to most 
risk assessments, there are pesticides as to which the common mechanism 
issues can be resolved. These pesticides include pesticides that are 
toxicologically dissimilar to existing chemical substances (in which 
case the Agency can conclude that it is unlikely that a pesticide 
shares a common mechanism of activity with other substances) and 
pesticides that produce a common toxic metabolite (in which case common 
mechanism of activity will be assumed).
    EPA does not have, at this time, available data to determine 
whether carfentrazone-ethyl 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, 
carfentrazone-ethyl 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 carfentrazone-ethyl has a 
common mechanism of toxicity with other substances.

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

    1. Acute risk. The Agency does not have a concern for acute dietary 
assessment since the available data do not indicate any evidence of 
significant toxicity from a one day or single event exposure by the 
oral route. An acute dietary risk assessment was not required.
    2. Chronic risk. The chronic dietary analysis indicates that 
exposure from the proposed temporary tolerances for use of 
carfentrazone-ethyl in/on corn and wheat for the U.S. population would 
account for less than 1% of the RfD. For children (1-6 years), the 
subgroup with the highest exposure, 1% of the RfD would be utilized. A 
chronic dietary risk (food and water) was not conducted for the 
following reasons: the short duration of this EUP, the small percentage 
of treated acres for corn and

[[Page 42244]]

wheat as a result of the proposed use (<1% of the total U.S. production 
for both commodities; and the fact that these commodities are blended 
before consumption). This chronic analysis for carfentrazone-ethyl is 
an upper-bound estimate of dietary exposure with all residues at 
tolerance level and assuming 100% of the commodities to be treated. 
Since only 4,000 acres of wheat and 4,000 acres of corn will be treated 
under this EUP program, which represents less than 1% of the total 
wheat and corn harvested in the United States, this dietary analysis 
represents an over estimate of the percent RfD that will be utilized by 
the proposed temporary tolerances. Therefore, the chronic dietary risk 
resulting from the proposed temporary tolerances for carfentrazone-
ethyl will not exceed the Agency's level of concern. EPA concludes that 
there is a reasonable certainty that no harm will result from aggregate 
exposure to carfentrazone-ethyl residues.

E. Aggregate Cancer Risk for U.S. Population

    The chronic dietary analysis indicates that exposure from the 
proposed temporary tolerances for use of carfentrazone-ethyl in/on corn 
and wheat for the U.S. population would account for less than 1% RfD. 
There is no concern for cancer risks identified. Data from available 
studies do not indicate a treatment-related tumor problem, and cancer 
endpoints have not been identified.

F. 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 carfentrazone-ethyl, EPA considered data from 
developmental toxicity studies in the rat and rabbit. 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.
    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 MOE 
and uncertainty factor (usually 100 for combined inter- and intra-
species variability)) and not the additional tenfold MOE/uncertainty 
factor when EPA has a complete data base under existing guidelines and 
when the severity of the effect in infants or children or the potency 
or unusual toxic properties of a compound do not raise concerns 
regarding the adequacy of the standard MOE/safety factor.
    ii. Developmental toxicity studies-- a. Rabbits. A prenatal oral 
developmental toxicity study in rabbits with dose levels of 0, 10, 40, 
150, or 300 mg/kg/day with a maternal LOEL of 300/mg/kg/day and the 
maternal NOEL of <gr-thn-eq> 150 mg/kg/day. There was not evidence of 
treatment-related prenatal developmental toxicity.
    b. Rat. A prenatal oral developmental toxicity study in the rat at 
dose levels of 0, 100, 600, or 1,250 mg/kg/day with a maternal LOEL of 
600 m g/kg/day based on staining of the abdominogential area and of the 
cage pan liner; and with the maternal NOEL of 100 mg/kg/day. The 
developmental NOEL of 1,250 mg/kg/day was based upon a significant 
increase in the litter incidences of wavy and thickened ribs and with 
the developmental NOEL of 600 mg/kg/day.
    iii. Reproductive toxicity study. Under Title 40 of the Code of 
Federal Regulations, part 158, Sec. 158.340, a 2-generation 
reproduction study is not required for an EUP when the TMRC is less 
than 50% of the RfD. Exposure from the proposed temporary tolerance of 
carfentrazone-ethyl from use on wheat and corn will account for less 
than 1% of the RfD.
    iv. Pre- and post-natal sensitivity. There was no evidence of pre-
and post-natal sensitivity in the prenatal oral developmental studies 
discussed above.
    v. Conclusion. All required toxicology studies have been completed 
for this phase of the registration process. The required developmental 
studies show no pre-natal sensitivity. Based on these findings as well 
as the generally low toxicity seen in all of the carfentrazone studies, 
EPA concludes there is reliable data supporting not using an additional 
10-fold safety factor for the protection of infants and children. EPA 
believes the 1,000-fold safety factor used in assessing the 
carfentrazone risk is adequate to protect all consumers. The 1,000-fold 
safety factor includes a 100-fold factor for intra- and inter-species 
differences and a 10-fold factor because the RfD was based on 
subchronic study.
    2. Chronic risk. EPA has concluded that aggregate exposure to 
carfentrazone-ethyl from food will utilize 1% of the RfD for infants 
and children. EPA generally has no concern for exposures below 100% of 
the RfD because the RfD represents the level at or below which daily 
aggregate dietary exposure over a lifetime will not pose appreciable 
risks to human health. Despite the potential for exposure to 
carfentrazone-ethyl 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 carfentrazone-ethyl residues.

III. Other Considerations

A. Metabolism In Plants and Animals

    The metabolism of carfentrazone-ethyl in plants is adequately 
understood for the purposes of these tolerances. For the purposes of 
this EUP, the residues of concern are the parent carfentrazone-ethyl 
and its two major metabolites. The nature of the residue in animals has 
not been reported. Due to the non-quantifiable carfentrazone-ethyl 
residues in/on the treated RACs, except wheat forage (there is a label 
feeding restriction in this EUP) fed to livestock and the limited 
number of acres involved, there is no expectation of secondary residues 
in livestock commodities of meat, meat-by-products, fat, milk, and 
eggs.

B. Analytical Enforcement Methodology

    There is a practical analytical method for detecting and measuring 
levels of carfentrazone and its metabolites in or on food with a limit 
of detection that allows monitoring of food with residues at or above 
the levels set in these tolerances. The proposed analytical method for 
determining residues is hydrolysis followed by gas chromatographic 
separation. For the parent carfentrazone-ethyl, acceptable method 
recoveries were established at a limit of quantitation (LOQ) of 0.05 
ppm, and a limit of detection (LOD) was set at 0.01 ppm for all the 
field corn and wheat crop matrices. The methodology can also be used to 
determine major plant metabolites with similar LOQs and LODs. No 
analytical method for meat, milk and eggs has been submitted by the 
registrant. Since no temporary tolerances have been proposed for animal 
RACs, an analytical enforcement

[[Page 42245]]

method for animals is not required for this EUP.

C. Magnitude of Residues

    The magnitude of the residue in animals has not been reported. 
These data will not be required for this EUP due to the non-
quantifiable carfentrazone-ethyl residues in/on treated RACs (corn 
forage, fodder, and grain, and wheat hay, straw, and grain) fed to 
livestock and the limited number of acres involved. Residues were only 
found in wheat forage, therefore for this EUP only, a grazing 
restriction must be included to prohibit the grazing and harvesting of 
wheat forage as a feedstuff.

D. International Residue Limits

    There is no Codex proposal, no Canadian or Mexican limits for 
residues of carfentrazone-ethyl in corn or wheat. A compatibility issue 
is not relevant to the proposed tolerances for either crop.

IV. Conclusion

    Therefore, the temporary tolerance is extended for combined 
residues of carfentrazone (ethyl-alpha-2-dichloro-5-[4-
(difluoromethyl)-4,5-dihydro-3-methyl-5-oxo-1H-1,2,4-triazol-1-yl]-4-
fluorobenzene-propanoate) and its metabolites in wheat at 0.20 ppm and 
corn at 0.15 ppm.

V. 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 October 6, 1998, 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.

VI. Public Record and Electronic Submissions

    EPA has established a record for this rulemaking under docket 
control number [OPP-300686] (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 119 of the Public Information and Records 
Integrity Branch, Information Resources and Services Division (7502C), 
Office of Pesticide Programs, Environmental Protection Agency, Crystal 
Mall #2, 1921 Jefferson Davis Highway, Arlington, VA.
    Electronic comments may be sent directly to EPA at:
    opp-docket@epamail.epa.gov.


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

VII. Regulatory Assessment Requirements

    This final rule extends a temporary tolerance under FFDCA section 
408(d) in response to a petition submitted to the Agency. 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 on the basis of a petition under FFDCA section 408(d), such 
as the temporary tolerance in this final rule, do not require the 
issuance of a proposed rule, the requirements of the Regulatory 
Flexibility Act (RFA) (5 U.S.C. 601 et seq.) do not apply. 
Nevertheless, the Agency has previously assessed whether establishing 
tolerances, exemptions from tolerances, raising tolerance levels or 
expanding exemptions might adversely impact small entities and 
concluded, as a generic matter, that there is no adverse economic 
impact. The factual basis for the Agency's generic certification for 
tolerance actions published on May 4, 1981 (46 FR 24950) and was 
provided to the Chief Counsel for Advocacy of the Small Business 
Administration.

[[Page 42246]]

VIII. Submission to Congress and the Comptroller General

    The Congressional Review Act, 5 U.S.C. 801 et seq., as added by the 
Small Business Regulatory Enforcement Fairness Act of 1996, generally 
provides that before a rule may take effect, the agency promulgating 
the rule must submit a rule report, which includes a copy of the rule, 
to each House of the Congress and to the Comptroller General of the 
United States. EPA will submit a report containing this rule and other 
required information to the U.S. Senate, the U.S. House of 
Representatives, and the Comptroller General of the United States prior 
to publication of the rule in the Federal Register. This rule is not a 
``major rule'' as defined by 5 U.S.C. 804(2).

List of Subjects in 40 CFR Part 180

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

    Dated: July 29, 1998.

Arnold E. Layne,

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.

Sec. 180.515   [AMENDED]

    2. In Sec. 180.515 by amending the table in paragraph (a) for all 
of the commodities by changing the date ``5/8/98'' to read ``5/8/99.''

[FR Doc. 98-21201 Filed 8-6-98; 8:45 am]
BILLING CODE 6560-50-F