[Federal Register Volume 62, Number 228 (Wednesday, November 26, 1997)]
[Rules and Regulations]
[Pages 62954-62961]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-30946]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 180

[OPP-300576; FRL-5754-9]
RIN 2070-AB78


Tefluthrin; Pesticide Tolerance

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: This regulation establishes tolerances for combined residues 
of tefluthrin and its metabolite in or on corn, grain, field and pop; 
corn, forage and fodder, field, pop and sweet; and corn, fresh 
(including sweet K and corn with husk removed (CWHR)) at 0.06 parts per 
million (ppm). It also removes time limitations for tolerances for 
residues of tefluthrin on the same commodities that expire on November 
15, 1997. Zeneca Ag Products requested these tolerances under the 
Federal Food, Drug, and Cosmetic Act (FFDCA), as amended by the Food 
Quality Protection Act of 1996 (Pub. L. 104-170).

DATES: This regulation is effective November 26, 1997. Objections and 
requests for hearings must be received by EPA on or before January 26, 
1998.

ADDRESSES: Written objections and hearing requests, identified by the 
docket control number, [OPP-300576], 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-300576], must also be submitted to: Public 
Information and Records Integrity Branch, Information Resources and 
Services Division (7502C), Office of Pesticide Programs, Environmental 
Protection Agency, 401 M St., SW., Washington, DC 20460. In person, 
bring a copy of objections and hearing requests to Rm. 1132, CM #2, 
1921 Jefferson Davis Hwy., Arlington, VA.
    A copy of objections and hearing requests filed with the Hearing 
Clerk may also be submitted electronically by sending electronic mail 
(e-mail) to: [email protected]. Copies of objections and 
hearing requests must be submitted as an ASCII file avoiding the use of 
special characters and any form of encryption. Copies of objections and 
hearing requests will also be accepted on disks in WordPerfect 5.1 file 
format or ASCII file format. All copies of objections and hearing 
requests in electronic form must be identified by the docket control 
number [OPP-300576]. 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: Beth Edwards, 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) 305-5400, e-mail: 
[email protected].

SUPPLEMENTARY INFORMATION: On February 1, 1989 (54 FR 5080), EPA 
established time limited tolerances under Section 408 of the Federal 
Food, Drug, and Cosmetic Act (FFDCA), 21 U.S.C. 346 a(d) and 348 for 
residues of tefluthrin on corn, grain, field, and pop; corn, forage and 
fodder, field and pop. As additional crop tolerances were established, 
they were also made time-limited. These tolerances expire on November 
15, 1997. Zeneca Ag Products, on September 15, 1997, requested that the 
time limitation for tolerances established for residues of the 
insecticide tefluthrin in the corn commodities mentioned above be 
removed based on environmental effects data that they had submitted as 
a condition of the registration. Zeneca Ag Products also submitted a 
summary of its petition as required under the FFDCA as amended by the 
Food Quality Protection Act (FQPA) of 1996 (Pub. L. 104-170).
    In the Federal Register of September 25, 1997 (62 FR 50337) (FRL-
5748-2), 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 petitions (PP 7F3521 and 4F4406) for tolerances 
by Zeneca Ag Products, P.O. Box 15458, Wilmington, DE, 19850-5458. This 
notice included a summary of the petition prepared by Zeneca Ag 
Products, the registrant. There were no comments received in response 
to the notice of filing.
    The petitions requested that 40 CFR 180.440 be amended by removing 
the time-limitation for tolerances for combined residues of the 
insecticide and pyrethroid tefluthrin and its metabolite (Z)-3-(2-
chloro-3,3,3-trifluoro-1-propenyl)-2,2-dimethylcyclopropanecarboxylic 
acid, in or on corn, grain, field and pop; corn, forage and fodder, 
field, pop and sweet; and corn, fresh (including sweet K and corn with 
husk removed (CWHR)) at 0.06 part per million (ppm).
    The basis for the time-limited tolerances that expire November 15, 
1997, was given in the Federal Register of October 20, 1993 (58 FR 
54094). These time-limited tolerances were predicated on the expiration 
of pesticide product registrations that were made conditional due to 
lack of certain ecological and environmental effects data. The 
rationale for using time-limited tolerances was to encourage pesticide 
manufacturers to comply with the conditions of registration in a timely 
manner. There is no regulatory requirement to make tolerances time-
limited due to the conditional status of a product registration under 
the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), as 
amended. It is current EPA policy to no longer establish time 
limitations on tolerance(s) with expiration dates if none of the 
conditions of registration have any bearing on human dietary risk. The 
current petition action meets that condition and thus the expiration 
dates associated with specific crop tolerances are being deleted.

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

[[Page 62955]]

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 3 
sources are not typically added because of the very low probability of 
this occurring in most cases, and because the other conservative 
assumptions built into the assessment assure adequate protection of 
public health. However, for cases in which high-end exposure can 
reasonably be expected from multiple sources (e.g. frequent and 
widespread homeowner use in a specific geographical area), multiple 
high-end risks will be aggregated and presented as part of the 
comprehensive risk assessment/characterization. Since the toxicological 
endpoint considered in this assessment reflects exposure over a period 
of at least 7 days, an additional degree of conservatism is built into 
the assessment; i.e., the risk assessment nominally covers 1-7 days 
exposure, and the toxicological endpoint/NOEL is selected to be 
adequate for at least 7 days of exposure. (Toxicity results at lower 
levels when the dosing duration is increased.)
    Intermediate-term risk results from exposure for 7 days to several 
months. This assessment is handled in a manner similar to the short-
term risk assessment.
    Chronic risk assessment describes risk which could result from 
several months to a lifetime of exposure. For this assessment, risks 
are aggregated considering average exposure from all sources for 
representative population subgroups including infants and children.

B. Aggregate Exposure

    In examining aggregate exposure, FFDCA section 408 requires that 
EPA take into account available and reliable information concerning 
exposure from the pesticide residue in the food in question, residues 
in other foods for which there are tolerances, residues in ground water 
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

[[Page 62956]]

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.

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 
tefluthrin and to make a determination on aggregate exposure, 
consistent with section 408(b)(2), for combined residues of tefluthrin 
and its metabolite on corn, grain, field and pop; corn, forage and 
fodder, field, pop and sweet; and corn, fresh (including sweet K and 
corn with husk removed (CWHR)) at 0.06 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 tefluthrin are 
discussed below.
    1. Acute toxicity studies with the technical grade of the active 
ingredient tefluthrin: oral LD50 in the rat is 21.8 
milligrams/kilogram (mg/kg) for males and 34.6 mg/kg for females - 
Toxicity Category I; dermal LD50 in the rat is 316 mg/kg in 
males and 177 mg/kg in females - Toxicity Category I; acute inhalation 
LC50 in the rat is 0.037 mg/l and 0.049 mg/l in male and 
female rats, respectively - Toxicity Category I; the primary eye 
irritation study in the rabbit was an invalid study; primary dermal 
irritation study in the rabbit showed slight irritation - Toxicity 
Category IV; dermal sensitization study in the guinea pig showed no 
skin sensitization; and the acute delayed neurotoxicity study did not 
show acute delayed neurotoxicity.
    2. In an oral toxicity study, rats were dosed at 0, 25, 100, or 400 
ppm (1.25, 5, or 20 milligrans/kilogram/day) (mg/kg/day) for 21 days. 
The LOEL for females for this 21-day oral toxicity study is 400 ppm 
(equivalent to approximately 20 mg/kg/day) based on decreased body 
weight gain, decreased platelet counts, and increased WBC and 
lymphocytes in the high-dose females. The NOEL for females is 100 ppm 
(equivalent to approximately 5 mg/kg/day). The NOEL in males was not 
observed.
    3. In a subchronic oral toxicity study, rats were dosed at 0, 50, 
150, or 350 ppm (2.5, 7.5, or 17.5 mg/kg/day) for 90 days. The LOEL for 
this 90-day feeding study is 150 ppm (equivalent to approximately 7.5 
mg/kg/day) based on changes in hemoglobin, cholesterol, and liver 
weight in the mid-dose animals. The NOEL is 50 ppm (equivalent to 
approximately 2.5 mg/kg/day).
    4. In a subchronic oral toxicity study, dogs were dosed at 0, 0.1, 
0.5, or 1.5 mg/kg/day for 90 days. The LOEL for this 90-day oral 
toxicity study is 1.5 mg/kg/day based on thyroid changes, and increased 
levels of plasma triglycerides and aspartate transaminase observed at 
the high-dose. The NOEL is 0.5 mg/kg/day.
    5. In an oral toxicity study, mice were dosed at 0, 25, 75, 200, or 
400 ppm (0, 3.75, 11.3, 30.0, or 60.0 mg/kg/day) for 28 days. The LOEL 
is 400 ppm (equivalent to approximately 60 mg/kg/day) based on 
decreased body weight gains in both sexes and final body weights in 
females. The NOEL is 200 ppm (equivalent to approximately 30 mg/kg/
day).
    6. In a dermal toxicity study, rats were dosed at 0, 0.1, 1.0, or 
50 mg/kg. The LOEL for skin effects for this 21-day dermal toxicity 
study is 50.0 mg/kg based on acanthosis, necrosis epidermis, and 
inflammatory cell infiltrate dermis observed in the high-dose animals. 
The NOEL for skin effects is 1.0 mg/kg). The NOEL for neurological 
effects (the observed postural effects) may be between 0.025 and 0.1 
mg/kg.
    7. In a chronic/oncogenicity study, mice were dosed at 0, 25, 100, 
or 400 ppm (actual dose levels were equivalent to 3.4, 13.5, or 54.4 
mg/kg/day) for 104 weeks. The chronic LOEL is 13.5 mg/kg based on 
hemangiomatous changes of the uterus and liver necrosis observed in the 
mid- and high-dose females. The chronic NOEL is 3.4 mg/kg. Under the 
conditions of this study, there was no evidence of carcinogenic 
potential.
    8. In a chronic toxicity study, dogs were dosed at dose levels of 
0, 0.1, 0.5, and 2 mg/kg/day for 12 months. The LOEL for this chronic 
study is 2.0 mg/kg/day based on the increased incidence of ataxia in 
both sexes at the high-dose. The NOEL is 0.5 mg/kg/day.
    9. In a chronic/oncogenicity study, rats were dosed for 24 months 
at 0, 25, 100, or 400 ppm (actual dose levels were equivalent to 1.1, 
4.6, or 18.2 mg/kg/day). The chronic LOEL is 4.6 mg/kg/day based on 
decreased body weights, and neurotoxicity and clinical chemistry 
changes in the mid- and high-dose animals. The chronic NOEL is 1.1 mg/
kg/day. Under the conditions of this study, there was no evidence of 
carcinogenic potential.
    10. In a developmental toxicity study, rats were dosed at 0, 1, 3, 
or 5 mg/kg/day from days 7 through 16 of gestation. The maternal LOEL 
is 3 mg/kg/day, based on treatment-related decrease body weight gains 
during dosing. The maternal NOEL is 1 mg/kg/day. Developmental toxicity 
was demonstrated at 5 mg/kg/day as an increase in the fetal incidence 
of bilaterally unossified calcanea (92.9% vs. 87.5% in controls, 
p<0.05; litter incidence was not shown) and a slight increase in the 
pes score (3.05 vs. 2.96 in controls) indicating slight inhibition of 
ossification at these sites. There were no treatment-related effects on 
the number, growth, and survival of the young in utero. In addition, 
the inter-group differences in the mean numbers of corpora lutea, 
implantations, pre- and post- implantation deaths, live fetuses, 
proportion of male fetuses, and fetal weights were not remarkable. The 
developmental LOEL is 5 mg/kg/day, based on inhibited ossification. The 
developmental NOEL is 3 mg/kg/day.
    11. In a developmental toxicity study, rabbits were dosed at 0, 3, 
6, or 12 mg/kg/day from days 7 through 19 of gestation. The maternal 
LOEL is 3 mg/kg/day, based on treatment-related clinical signs of 
toxicity (tremors). The maternal NOEL is <3 mg/kg/day. There was no 
developmental toxicity demonstrated at any dose level. There were no 
treatment-related effects on in utero survival and growth or on litter 
size and sex ratio of the fetuses. The skeletal variant data showed 
significant (p<0.01 or 0.05) increases in incidence of extra thoracic 
ribs and 27 pre-sacral vertebrae among fetuses in the dosed groups; 
however, when the litter was used as the unit for comparison, the 
incidences of these respective variants were comparable between all 
groups. The incidences of these variants were not biologically 
significant. The NOEL for developmental toxicity is 12 mg/kg/day. The 
developmental LOEL was not observed.
    12. In a multi-generation reproduction study, rats were dosed at 0, 
15, 50, or 250 ppm (0, 0.75, 2.5, or 12.5 mg/kg/day). The LOEL for 
parental toxicity is 12.5 mg/kg/day, based on lowered body

[[Page 62957]]

weight gains, and the NOEL is 2.5 mg/kg/day. The LOEL for neurotoxic 
effects is 2.5 mg/kg/day, based on abnormal, splayed, or high-stepping 
gait. The NOEL for neurotoxic effects is 0.75 mg/kg/day. Reproductive 
toxicity was demonstrated at the high-dose as lowered pup body weight 
gain throughout the study in all generations and in both sexes. 
Additionally, total litter weight was decreased on day 29 in all of the 
high-dose groups. The LOEL for reproductive toxicity is 12.5 mg/kg/day, 
based on lowered pup body weight gains. The reproductive NOEL is 2.5 
mg/kg/day.
    13. Mutagenicity. There is no mutagenicity concern. The submitted 
studies satisfy the pre-1991 mutagenicity test battery and the new 
mutagenicity testing requirements. There are seven acceptable studies: 
one dominant lethal study in mice; reverse mutation assay (Salmonella 
typhimurium); one forward mutation assay in mammalian cells; one mouse 
lymphoma assay, one in vivo chromosomal aberration assay, in vitro 
chromosome aberration study; one UDS assay in primary rat hepatocytes. 
All these studies were negative.
    14. Metabolism. In both rats and dogs, when given either 1 or 10 
mg/kg, most of the radioactivity was found in the feces unchanged and 
most urinary metabolites were conjugated. Approximately 30% of the 
administered dose was absorbed and excreted in the urine in both 
species. Single doses in both rats and dogs were excreted within 48 
hours, 50-65% in feces and 20-30% in the urine. In rats, a biliary 
fistula experiment suggested that the radioactivity measured in the 
feces may be partially due to biliary excretion. Studies also suggest 
that oxidation precedes the ester body cleavage. In rats, the halflife 
in the liver is 4.8 days, in the fat is 13.3 days and in the blood is 
10.6 days. In a study with rat fat, half of the radioactive residues 
could be attributed to the parent and the remaining residues consisted 
of a mixture of fatty acid esters of hydroxylated parent metabolites.
    15. Neurotoxicity. No acceptable mammalian neurotoxicity studies 
are available. In a supplementary study, 10 animals/sex/group were 
given either vehicle, 2,5-hexanedione or 5 mg/kg or 15 mg/kg 
tefluthrin. The positive control, 2,5-hexanedione, elicited the 
appropriate neurotoxicological response. No consistent effects on motor 
or sensory nerve electrophysiology or function or clinical signs of 
neurotoxicity were evident in animals treated with either 5 or 15 mg/kg 
tefluthrin. A slight but significant increase in pull-up time was 
observed on day 12 in males which was accompanied by a significant 
decrease in both SNCV and the amplitude of the SNAP. Both quickly 
returned to values similar to control values, and did not decrease 
again.
    Neurotoxicity studies will be required under a special Data Call-In 
letter pursuant to section 3(c)(2)(B) of FIFRA. Although these data are 
lacking, EPA has sufficient toxicity data to support these tolerances 
and these additional studies are not expected to significantly change 
the risk assessment.

B. Toxicological Endpoints

    1. Acute toxicity. For acute dietary risk assessment, EPA 
recommends use of a NOEL of 0.5 mg/kg/day based on increased incidence 
of tremors and ataxia in both sexes of dogs at 2.0 mg/kg/day (LOEL) on 
day 1 of the study from the 1 year oral chronic toxicity study in dogs.
     2. Short - and intermediate - term toxicity. For short- and 
intermediate term MOE's, EPA recommends use of a NOEL of 0.5 mg/kg/day 
based on increased incidence of tremors and ataxia in both sexes of 
dogs at 2.0 mg/kg/day (LOEL) from the one year oral toxicity study in 
dogs and use of a dermal absorption rate of 25%. A dermal absorption 
rate of 25% was recommended based on the weight-of-the-evidence 
available for structurally related pyrethroids.
     3. Chronic toxicity. EPA has established the RfD for tefluthrin at 
0.005 milligrams/kilogram/day (mg/kg/day). This RfD is based on 
increased incidence of tremors and ataxia in both sexes of dogs in a 
chronic toxicity study and an uncertainty factor of 100 to account for 
both interspecies extrapolation and intraspecies variability.
    4. Carcinogenicity. No evidence of carcinogenicity was demonstrated 
in studies conducted with mice or rats.

C. Exposures and Risks

    1. From food and feed uses.Tolerances have been established (40 CFR 
180.440) for the combined residues of tefluthrin and its metabolite, in 
or on corn. Risk assessments were conducted by EPA to assess dietary 
exposures and risks from tefluthrin 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. Percent of crop treated data and 
tolerance values were used in conjunction with Monte Carlo. The acute 
dietary MOE at the 99.9th percentile for the most highly exposed 
population subgroup (non-nursing infants <1 year old) is 691. The MOE 
at the 99.9th percentile for the general U.S. population is 1,469. EPA 
concludes that there is a reasonable certainty of no harm for MOEs of 
100 or greater. Therefore, the acute dietary risk assessment for 
tefluthrin indicates a reasonable certainty of no harm.
    ii. Chronic exposure and risk. The chronic dietary exposure 
assessment used tolerance values and percent crop treated information. 
The RfD used for the chronic dietary analysis is 0.005 mg/kg/day. The 
risk assessment resulted in use of less than one percent (0.1%) of the 
RfD for the U.S. population. The percent of the RfD used for the most 
highly exposed population subgroup (children ages one to six) is 0.3%.
    EPA notes that the acute dietary risk assessments used Monte Carlo 
modeling (in accordance with Tier 3 of EPA June 1996 ``Acute Dietary 
Exposure Assessment'' guidance document) incorporating tolerance levels 
and percent of crop treated refinements. The chronic dietary risk 
assessments used tolerance levels and percent crop treated information.
    Section 408(b)(2)(E) authorizes EPA to consider available data and 
information on the anticipated residue levels of pesticide residues in 
food and the actual levels of pesticide chemicals that have been 
measured in food. If EPA relies on such information, EPA must require 
that data be provided five years after the tolerance is established, 
modified or left in effect, demonstrating that the levels in food are 
not above the levels anticipated. Following the initial data 
submission, EPA is authorized to require similar data on a timeframe it 
deems appropriate. Section 408(b)(2)(F) allows the Agency to use data 
on the actual percent of crop treated when establishing a tolerance 
only where the Agency can make the following findings: (1) that the 
data used are reliable and provide a valid basis for showing the 
percentage of food derived from a crop that is likely to contain 
residues; (2) that the exposure estimate does not underestimate the 
exposure for any significant subpopulation and; (3) where data on 
regional pesticide use and food consumption are available, that the 
exposure estimate does not understate exposure for any regional 
population. In addition, the Agency must provide for periodic 
evaluation of any estimates used.
    The percent of crop treated estimates for tefluthrin were derived 
from federal and market survey data. EPA considers these data reliable. 
A range of estimates

[[Page 62958]]

are supplied by this data and the upper end of this range was used for 
the exposure assessment. By using this upper end estimate of percent 
crop treated, the Agency is reasonably certain that exposure is not 
underestimate for any significant subpopulation. 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. Review of this regional data allows 
the Agency to be reasonably certain that no regional population is 
exposed to residue levels higher than those estimated by the Agency. To 
meet the requirement for data on anticipated residues, EPA will issue a 
Data Call-In (DCI) notice pursuant to FFDCA section 408(f) requiring 
submission of data on anticipated residues in conjunction with approval 
of the registration under the FIFRA.
    2. From drinking water. Tefluthrin is immobile in soil and, 
therefore, will not leach into ground water. Additionally, due to the 
insolubility and lipophilic nature of tefluthrin, any residues in 
surface water will rapidly and tightly bind to soil particles and 
remain with sediment, therefore not contributing to potential dietary 
exposure from drinking water.
    A screening evaluation of leaching potential of a typical synthetic 
pyrethroid was conducted using EPA's Pesticide Root Zone Model (PRZM). 
Based on this screening assessment, potential concentrations of a 
pyrethroid in ground water at depths of 1 to 2 meters are essentially 
zero (<0.001 ppb). Surface water concentrations for pyrethroids were 
estimated using PRZM1 and Exposure Analysis Modeling Systems (EXAMS) 
using standard EPA cotton runoff and Mississippi pond scenarios. The 
maximum concentration predicted in the simulation pond was 0.052 ppb. 
Concentrations in actual drinking water would be much lower than the 
levels predicted in the hypothetical, small, stagnant farm pond model 
since drinking water derived from surface water would normally be 
treated before consumption. Based on these analyses, the contribution 
of water to the dietary risk estimate is negligible. Therefore, EPA 
concludes that together these data indicate that residues are not 
expected to occur in drinking water.
    i. Acute exposure and risk. The acute drinking water exposure and 
risk estimates are 0.000040 mg/kg/day (MOE of 12,362) and 0.000078 mg/
kg/day (MOE of 6,439) for the overall U.S. population and non-nursing 
infants <1 year old, respectively.
    ii. Chronic exposure and risk. The chronic drinking water exposure 
and risk estimates are 0.000000 mg/kg/day (0.0% of RfD utilized) and 
0.000002 mg/kg/day (0.0% of RfD utilized) for the overall U.S. 
population and non-nursing infants <1 year old, respectively.
    3. From non-occupational non-dietary exposure. Tefluthrin is 
currently not registered for use on residential non-food sites; 
therefore, no non-occupational non-dietary exposure is expected.
    4. Cumulative exposure to substances with common mechanism of 
toxicity. Section 408(b)(2)(D)(v) requires that, when considering 
whether to establish, modify, or revoke a tolerance, the Agency 
consider ``available information'' concerning the cumulative effects of 
a particular pesticide's residues and ``other substances that have a 
common mechanism of toxicity.'' The Agency believes that ``available 
information'' in this context might include not only toxicity, 
chemistry, and exposure data, but also scientific policies and 
methodologies for understanding common mechanisms of toxicity and 
conducting cumulative risk assessments. For most pesticides, although 
the Agency has some information in its files that may turn out to be 
helpful in eventually determining whether a pesticide shares a common 
mechanism of toxicity with any other substances, EPA does not at this 
time have the methodologies to resolve the complex scientific issues 
concerning common mechanism of toxicity in a meaningful way. EPA has 
begun a pilot process to study this issue further through the 
examination of particular classes of pesticides. The Agency hopes that 
the results of this pilot process will increase the Agency's scientific 
understanding of this question such that EPA will be able to develop 
and apply scientific principles for better determining which chemicals 
have a common mechanism of toxicity and evaluating the cumulative 
effects of such chemicals. The Agency anticipates, however, that even 
as its understanding of the science of common mechanisms increases, 
decisions on specific classes of chemicals will be heavily dependent on 
chemical specific data, much of which may not be presently available.
    Although at present the Agency does not know how to apply the 
information in its files concerning common mechanism issues to most 
risk assessments, there are pesticides as to which the common mechanism 
issues can be resolved. These pesticides include pesticides that are 
toxicologically dissimilar to existing chemical substances (in which 
case the Agency can conclude that it is unlikely that a pesticide 
shares a common mechanism of activity with other substances) and 
pesticides that produce a common toxic metabolite (in which case common 
mechanism of activity will be assumed).
    EPA does not have, at this time, available data to determine 
whether tefluthrin 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, 
tefluthrin 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 tefluthrin has a common mechanism of toxicity 
with other substances.

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

    1. Acute risk. The acute aggregate risk assessment takes into 
account exposure from food and water. The acute aggregate MOE 
calculated at the 99.9th percentile for the overall U.S. population is 
1,316. The Agency has no cause for concern if total acute exposure 
calculated for the 99.9th percentile yields an MOE of 100 or larger. 
Therefore, the Agency concludes that there is reasonable certainty that 
no harm will result from acute aggregate exposure to tefluthrin 
residues in food and drinking water.
    2. Chronic risk. Using the Anticipated Residue Concentration (ARC) 
exposure assumptions described above, EPA has concluded that aggregate 
exposure to tefluthrin from food and water will utilize 0.1% of the RfD 
for the U.S. population. The major identifiable subgroup with the 
highest aggregate exposure is children age 1-6 years (discussed below). 
EPA generally has no concern for exposures below 100% of the RfD 
because the RfD represents the level at or below which daily aggregate 
dietary exposure over a lifetime will not pose appreciable risks to 
human health. EPA concludes that there is a reasonable certainty that 
no harm will result from aggregate exposure to tefluthrin residues.
    3. Short- and intermediate-term risk. Short- and intermediate-term 
aggregate exposure takes into account chronic dietary food and water 
(considered to be a background exposure level) plus indoor and outdoor 
residential exposure. Based on tefluthrin not being registered for 
residential non-food sites, EPA concludes that the aggregate short- and 
intermediate-term risks do not

[[Page 62959]]

exceed levels of concern (MOE less than 100), and that there is 
reasonable certainty that no harm will result from aggregate exposure 
to tefluthrin residues.

E. Aggregate Cancer Risk for U.S. Population

    No evidence of carcinogenicity was demonstrated in studies 
conducted mice or rats.

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 tefluthrin, EPA considered data from 
developmental toxicity studies in the rat and rabbit and a two-
generation reproduction study in the rat. The developmental toxicity 
studies are designed to evaluate adverse effects on the developing 
organism resulting from 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 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 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. In the prenatal developmental 
toxicity studies in rats and rabbits, the developmental NOEL was 
greater than the maternal NOEL, indicating a lack of sensitivity to in 
utero exposure. In rats, the maternal NOEL (1 mg/kg/day), based on body 
weight decreases at the LOEL of 3 mg/kg/day, which was based on 
ossification reductions in the extremities at 5 mg/kg/day. In the 
rabbit study, maternal pyrethroid toxicity was observed at all dose 
levels (maternal NOEL <3 mg/kg/day), but no developmental toxicity was 
observed (developmental NOEL >12 mg/kg/day).
    iii. Reproductive toxicity study. In the two-generation 
reproduction study in rats, offspring toxicity (reduced mean pup weight 
gain) was observed only at the highest dose level tested (250 ppm; 12.5 
mg/kg/day), while evidence of neurotoxicity in parental animals was 
observed at the systemic LOEL of 50 ppm (2.5 mg/kg/day). The offspring 
toxicity NOEL was 50 ppm (2.5 mg/kg/day) and the parental systemic NOEL 
was 15 ppm (0.75 mg/kg/day).
    iv. Pre- and post-natal sensitivity. The data demonstrated no 
indication of increased sensitivity of rats or to in utero and/or 
postnatal exposure with tefluthrin.
    v. Conclusion. The data base related to pre- and post-natal 
sensitivity is complete. Based on the above, EPA concludes that 
reliable data support use of the standard 100-fold uncertainty factor, 
and that an additional uncertainty factor is not needed to protect the 
safety of infants and children.
    2. Acute risk. The acute aggregate MOE calculated at the 99.9th 
percentile for non-nursing infants <1 year old is 623. EPA concluded 
that aggregate dietary acute risk (food plus water) would not exceed 
levels of concern. Therefore, the Agency has no acute aggregate concern 
due to exposure to tefluthrin through food and drinking water.
    3. Chronic risk. Using the conservative exposure assumptions 
described above, EPA has concluded that aggregate exposure to 
tefluthrin from food and water will utilize 0.3% of the RfD for 
children age 1-6 years. 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.
    4. Short- or intermediate-term risk. Based on tefluthrin not being 
registered for residential non-food sites, EPA concludes that the 
aggregate short- and intermediate-term risks do not exceed levels of 
concern, and that there is reasonable certainty that no harm will 
result.
    EPA concludes that there is a reasonable certainty that no harm 
will result to infants and children from aggregate exposure to 
tefluthrin residues.
    5. Special Docket. The complete acute and chronic exposure analyses 
(including dietary, non-dietary, drinking water, and residential 
exposure, and analysis of exposure to infants and children) used for 
risk assessment purposes can be found in the Special Docket for the 
FQPA under the title ``Risk Assessment for Extension of Tolerances for 
Synthetic Pyrethroids.'' Further explanation regarding EPA's decision 
regarding the additional safety factor can also be found in the Special 
Docket.

G. Endocrine Disrupter Effects

    EPA is required to develop a screening program to determine whether 
certain substances (including all pesticides and inerts) ``may have an 
effect in humans that is similar to an effect produced by a naturally 
occurring estrogen, or such other endocrine effect...'' The Agency is 
currently working with interested stakeholders, including other 
government agencies, public interest groups, industry and research 
scientists in developing a screening and testing program and a priority 
setting scheme to implement this program. Congress has allowed 3 years 
from the passage of FQPA (August 3, 1999) to implement this program. At 
that time, EPA may require further testing of this active ingredient 
and end use products for endocrine disrupter effects.

III. Other Considerations

A. Metabolism In Plants and Animals

    Plant metabolism studies indicate that tefluthrin per se is not 
translocated to plants but is degraded in soil to two principal 
metabolites that are capable of being taken up by plants. The 
metabolites are the products of the cleavage of the ester to the free 
acid (Z)-3-(2-chloro-3,3,3-trifluoro-1-propenyl)-2,2-
dimethylcyclopropane carboxylic acid (Metabolite Ia) and to 2,3,5,6-
tetrafluoro-4-hydroxymethylbenzoic acid (Metabolite VI). The Agency 
concluded that Metabolite VI need not be regulated.
    In animals, dosing with radioactive tefluthrin at level equivalent 
to 11 ppm in feed resulted in identifiable residues of tefluthrin and 
its metabolites in tissues but at levels below those capable of 
detection by proposed enforcement methods.

B. Analytical Enforcement Methodology

    Validated enforcement analytical methods are available for 
tefluthrin parent (Method PPRAM No. 85/1, The Determination of Residues 
of Tefluthrin in Crops and Soil-A Gas-Liquid Chromatographic Method) 
and for Metabolite Ia (Method GRAM-028 A Gas Chromatography Method for 
the

[[Page 62960]]

Determination of Residues of the Tefluthrin Metabolite PP890 in Crops 
of High and Low Moisture Content). The limits of quantitation of these 
methods are 0.01 ppm for tefluthrin and 0.05 ppm for Metabolite Ia.

C. Magnitude of Residues

    1. Plant commodities-- Field trial studies. No residues were 
detected in field trials conducted at maximum label rates and minimum 
PHIs. Tolerances were established at the limit of quantitation of the 
analytical method (0.06 ppm). The 0.06 ppm tolerances were used to 
estimate chronic and acute dietary exposure to potential residues of 
tefluthrin.
    2. Animal commodities. Studies conducted indicate that no residues 
are detected in animal tissues, milk, and eggs and therefore secondary 
residues would not be a concern. For that reason, no tolerances have 
been established on meat, milk, and eggs. Secondary residues were 
therefore not considered in these analyses.

D. International Residue Limits

    There are no Codex Maximum Residue Levels established for 
tefluthrin. No Canadian MRLs have been established for residues of 
tefluthrin on corn commodities. Mexico has established a tolerance for 
residues of tefluthrin on corn grain (0.06 ppm) which is in harmony 
with the U.S. tolerance.

IV. Conclusion

    Therefore, the tolerance is established for combined residues of 
tefluthrin and its metabolite in corn, grain, field and pop; corn, 
forage and fodder, field, pop and sweet; and corn, fresh (including 
sweet K and corn with husk removed (CWHR)) at 0.06 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 January 26, 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 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-300576] (including any comments and data submitted 
electronically). A public version of this record, including printed, 
paper versions of electronic comments, which does not include any 
information claimed as CBI, is available for inspection from 8:30 a.m. 
to 4 p.m., Monday through Friday, excluding legal holidays. The public 
record is located in Room 1132 of the Public Information and Records 
Integrity Branch, Information Resources and Services Division (7502C), 
Office of Pesticide Programs, Environmental Protection Agency, Crystal 
Mall #2, 1921 Jefferson Davis Hwy., Arlington, VA.
    Electronic comments may be sent directly to EPA at:
    [email protected].


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

VII. Regulatory Assessment Requirements

    This final rule establishes tolerances 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 tolerances in this final rule, do not require the issuance of a 
proposed rule, the requirements of the Regulatory Flexibility Act (RFA) 
(5 U.S.C. 601 et seq.) do not apply. Nevertheless, the Agency has 
previously assessed whether establishing tolerances, exemptions from 
tolerances,

[[Page 62961]]

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: November 14, 1997.

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

PART 180--[AMENDED]

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

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

    2. Section 180.440 is revised to read as follows:


Sec. 180.440  Tefluthrin; tolerances for residues.

    (a) General. Tolerances are established for the combined residues 
of the insecticide tefluthrin (2,3,5,6 tetrafluroro-4-
methylphenyl)methyl-(1 alpha, 3 alpha)-(Z)-()-3(2-chloro-
3,3,3-trifluoro-1-propenyl)-2,2-diemthylcyclopropanecarboxylate) and 
its metabolite (Z)-3-(2-chloro-3,3,3-trifluroro-1-propenyl)-2,2-
dimethylcyclopropanecarboxylic acid in or on the following commodities:

                                                                        
------------------------------------------------------------------------
                                                              Parts per 
                         Commodity                             million  
------------------------------------------------------------------------
Corn, field, fodder and forage, pop and sweet..............         0.06
Corn, fresh (including sweet K and corn with husk removed               
 (CWHR)....................................................         0.06
Corn, field, grain and pop.................................         0.06
------------------------------------------------------------------------

    (b) Section 18 emergency exemptions. [Reserved]
    (c) Tolerances with regional registrations. [Reserved]
    (d) Indirect or inadvertent residues. [Reserved]

[FR Doc. 97-30946 Filed 11-25-97; 8:45 am]
BILLING CODE 6560-50-F