[Federal Register Volume 62, Number 189 (Tuesday, September 30, 1997)]
[Rules and Regulations]
[Pages 51032-51038]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-25891]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 180
[OPP-300554; FRL-5744-8]
RIN 2070-AB78
Carfentrazone-ethyl; Temporary Pesticide Tolerance
AGENCY: Environmental Protection Agency (EPA).
ACTION: Final rule.
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SUMMARY: This regulation establishes 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-fluorobenzenepropanoate) and its major wheat metabolites in or on
corn (fodder, forage, and grain) and wheat (grain, hay, and straw). FMC
requested this tolerance under the Federal Food, Drug, and Cosmetic Act
(FFDCA), as amended by the Food Quality Protection Act of 1966 (Pub. L.
104-170).
DATES: This regulation is effective September 30, 1997. Objections and
requests for hearings must be received by EPA on or before December 1,
1997.
ADDRESSES: Written objections and hearing requests, identified by the
docket control number, OPP-300554, 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-300554], 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: opp-docket@epamail.epa.gov. Copies of objections and
hearing requests must be submitted as an ASCII file avoiding the use of
special characters and any form of encryption. Copies of objections and
hearing requests will also be accepted on disks in WordPerfect 5.1 file
format or ASCII file format. All copies of objections and hearing
requests in electronic form must be identified by the docket control
number OPP-300554. 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, 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 May 16, 1997 (62
FR 27040) (FRL-5717-4), 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) for 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
establishing 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-
fluorobenzenepropanoate), and its metabolite in or on field corn
forage, fodder, and grain at 0.15 ppm; and for wheat hay, straw, and
grain at 0.20 ppm part per million (ppm). This tolerance will expire on
May 8, 1998. This tolerance request was submitted along with an
application for an experimiental use permit (EUP). The EUP proposed the
experimental use of carfentrazone-ethyl on corn and wheat. Under FIFRA,
section 5 for experimental use permits, a temporary tolerance level
must be established if a pesticide may reasonably be expected to result
in any residue in or on 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 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. . . .''
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
[[Page 51033]]
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.
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 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-="" [[page="" 51034]]="" (difluoromethyl)-4,5-dihydro-3-methyl-5-oxo-1h-1,2,4-triazol-1-yl]-4-="" fluorobenzenepropanoate)="" and="" its="" metabolites="" on="" wheat="" at="" 0.20="" 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/="" kilograms/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.="" 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="" five="" males="" and="" five="" 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="" four="" 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=""> 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 1 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 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-fluorobenzenepropanoate), 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 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 1 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 the 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).="" i.="" acute="" exposure="" and="" risk.="" as="" part="" of="" the="" hazard="" assessment="" process,="" the="" agency="" reviews="" the="" available="" toxicological="" data="" base="" 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="" 1="" day="" or="" single="" event="" exposure="" by="" the="" oral="" route.="" therefore="" an="" acute="" dietary="" risk="" assessment="" was="" not="" required.="" ii.="" chronic="" exposure="" and="" risk.="" 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="" [[page="" 51035]]="" 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.="" 3.="" from="" non-dietary="" exposure.="" the="" proposed="" uses="" for="" this="" pesticide="" does="" not="" include="" uses="" that="" would="" result="" in="" a="" non-dietary,="" non-="" occupational="" exposure.="" 4.="" cumulative="" exposure="" to="" substances="" with="" common="" mechanism="" of="" toxicity.="" section="" 408(b)(2)(d)(v)="" requires="" that,="" when="" considering="" whether="" to="" establish,="" modify,="" or="" revoke="" a="" tolerance,="" the="" agency="" consider="" ``available="" information''="" concerning="" the="" cumulative="" effects="" of="" a="" particular="" pesticide's="" residues="" and="" ``other="" substances="" that="" have="" a="" common="" mechanism="" of="" toxicity.''="" 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="" 1="" 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="" the="" eup,="" 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;="" 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="" the="" 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--a.="" 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="" 10-="" fold="" 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="" data="" base="" unless="" epa="" determines="" that="" a="" different="" margin="" of="" safety="" will="" be="" safe="" for="" infants="" and="" children.="" margins="" of="" safety="" are="" incorporated="" into="" epa="" risk="" assessments="" either="" directly="" through="" use="" of="" a="" moe="" analysis="" or="" through="" using="" uncertainty="" (safety)="" factors="" in="" calculating="" a="" dose="" level="" that="" poses="" no="" appreciable="" risk="" to="" humans.="" epa="" believes="" that="" reliable="" data="" support="" using="" the="" standard="" moe="" and="" uncertainty="" factor="" (usually="" 100="" for="" combined="" inter-="" and="" intra-species="" variability)="" and="" not="" the="" additional="" tenfold="" moe/uncertainty="" factor="" when="" epa="" has="" a="" complete="" data="" base="" under="" [[page="" 51036]]="" 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.="" b.="" developmental="" toxicity="" studies.="" i.="" 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="">150 mg/kg/day. There was not evidence of treatment-
related prenatal developmental toxicity.
ii. 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
mg/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.
c. 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
carafentrazone-ethyl from use on wheat and corn will account for less
than 1% of the RfD.
d. Pre- and post-natal sensitivity. There was no evidence of pre-
and post-natal sensitivity in the prenatal oral developmental studies
discussed above.
e. 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
the 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 the 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 method for animals is not required for
the EUP.
C. Magnitude of Residues
The magnitude of the residue in animals has not been reported.
These data will not be required for the 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 the 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 established 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-
fluorobenzenepropanoate) 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 December 1, 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
[[Page 51037]]
that available evidence identified by the requestor would, if
established, resolve one or more of such issues in favor of the
requestor, taking into account uncontested claims or facts to the
contrary; and resolution of the factual issues in the manner sought by
the requestor would be adequate to justify the action requested (40 CFR
178.32). Information submitted in connection with an objection or
hearing request may be claimed confidential by marking any part or all
of that information as CBI. Information so marked will not be disclosed
except in accordance with procedures set forth in 40 CFR part 2. A copy
of the information that does not contain CBI must be submitted for
inclusion in the public record. Information not marked confidential may
be disclosed publicly by EPA without prior notice.
VI. Public Docket
EPA has established a record for this rulemaking under docket
control number OPP-300554 (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: 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 establishes 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.
VIII. Submission to Congress and the General Accounting Office
Under 5 U.S.C. 801(a)(1)(A), as added by the Small Business
Regulatory Enforcement Fairness Act of 1996, the Agency has submitted a
report containing this rule and other required information to the U.S.
Senate, the U.S. House of Representatives, and the Comptroller General
of the General Accounting Office prior to publication of this rule in
today's Federal Register. This is not a ``major rule'' as defined by 5
U.S.C. 804(2).
List of Subjects in 40 CFR Part 180
Environmental protection, Administrative practice and procedure,
Agricultural commodities, Pesticides and pests, Reporting and
recordkeeping requirements.
Dated: September 22, 1997.
Stephen L. Johnson,
Acting Director, Office of Pesticide Programs.
Therefore, 40 CFR Chapter I is amended as follows:
PART 180--[AMENDED]
1. The authority citation for part 180 continues to read as
follows:
Authority: 21 U.S.C. 346a and 371.
2. By adding Sec. 180.515, to read as follows:
Sec. 180.515 Carfentrazone-ethyl; temporary tolerances for residues.
(a) General. Temporary tolerances are established 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-fluorobenzenepropanoate) and its major wheat 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),3-hydroxymethyl-F8426-chloropropionic acid
(alpha,2-dichloro-5-[4-difluoromethyl)-4,5-dihydro-3-hydroxymethyl-5-
oxo-1H-1,2,4-triazol-1-yl]-4-fluorobenzenepropanoic acid) and 3-
desmethyl-F8426 chloropropionic acid (alpha,2-dichloro-5-[4-
difluoromethyl)-4,5-dihydro-5-oxo-1H-1,2,4-triazol-1-yl]-4-
fluorobenzenepropanoic acid) and in or on the following food
commodities:
------------------------------------------------------------------------
Expiration/
Commodity Parts per revocation
million date
------------------------------------------------------------------------
Corn fodder................................... 0.15 5/8/98
Corn forage................................... 0.15 5/8/98
Corn grain.................................... 0.15 5/8/98
Wheat hay..................................... 0.2 5/8/98
Wheat grain................................... 0.2 5/8/98
Wheat straw................................... 0.2 5/8/98
------------------------------------------------------------------------
(b) Section 18 emergency exemptions. [Reserved]
(c) Tolerances with regional registrations. [Reserved]
[[Page 51038]]
(d) Indirect or inadvertent residues. [Reserved]
[FR Doc. 97-25891 Filed 9-29-97; 8:45 am]
BILLING CODE 6560-50-F
