[Federal Register Volume 62, Number 95 (Friday, May 16, 1997)]
[Rules and Regulations]
[Pages 26954-26960]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-12912]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 180

[OPP-300492; FRL-5718-4]
RIN 2070-AB78


Pyridaben; Pesticide Tolerance

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: This regulation establishes time-limited tolerances with an 
expiration date of May 31, 2001 for residues of the pesticide pyridaben 
[2-tert-butyl-5-(4-tert-butylbenzylthio)-4-chloropyridazin-3(2H)-one] 
in or on the food commodities apples, wet apple pomace, pears, citrus, 
citrus oil, almonds, almond hulls, meat, milk and fat. A petition was 
submitted by BASF Corporation to EPA under the Federal Food, Drug, and 
Cosmetic Act (FFDCA) as amended by the Food Quality Protection Act of 
1996 (Pub. L. 104-170) requesting the tolerance. These tolerances will 
expire and are revoked on May 31, 2001.

DATES: This regulation becomes effective May 16, 1997. Objections and

[[Page 26955]]

requests for hearings must be received by EPA on or before July 15, 
1997.

ADDRESSES: Written objections and hearing requests, identified by the 
docket control number, [OPP-300492], 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-300492], should 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 Highway, 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[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-300492]. 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: Marion Johnson Jr. Product 
Manager (PM) 10, 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: Rm. 
210, CM #2, 1921 Jefferson Davis Highway, Arlington, VA (703) 305-6788, 
e-mail: [email protected].
SUPPLEMENTARY INFORMATION: EPA issued a notice, in the March 12, 1997 
Federal Register (62 FR 11450)(FRL-5592-7), which announced that BASF 
Corporation had submitted pesticide petitions (PP) 5F4543 (on citrus), 
and 6F4651 (on apples), 6F4741 (on pears), and 6F4721 (on almonds). 
Pesticide petitions 5F4543, 6F4651, 6F4741 and 6F4721 requested that 
the Administrator, pursuant to section 408 of the Federal Food, Drug, 
and Cosmetic Act (FFDCA), 21 U.S.C 346a, amend 40 CFR part 180 to 
establish tolerances for residues of the pesticide pyridaben [2-tert-
butyl-5-(4-tert-butylbenzylthio)-4-chloropyridazin-3(2H)-one; EPA 
Chemical No. 129105; CAS No. 96489-71-3] in or on the food commodities: 
apples, wet apple pomace, pears, citrus, dried citrus pulp, citrus oil, 
almonds, and almond hulls. The proposed tolerance levels for pyridaben 
and its metabolites are:

------------------------------------------------------------------------
                                                              Parts per 
                         Commodity                             million  
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Almond hulls...............................................          4.0
Almonds....................................................         0.05
Apple pomace, wet..........................................          1.0
Apples.....................................................          0.6
Citrus.....................................................          0.5
Citrus oil.................................................           10
Citrus pulp, dried.........................................          1.5
Milk.......................................................         0.01
Fat........................................................         0.05
Meat.......................................................         0.05
Meat by-products...........................................         0.05
Pears......................................................         0.75
------------------------------------------------------------------------

    As required by section 408(d) of the FFDCA, as recently amended by 
the Food Quality Protection Act, Pub. L. 104-170, BASF included in the 
notice of filing a summary of the petitions and authorization for the 
summary to be published in the Federal Register in a notice of receipt 
of the petition. The summary of the petitions prepared by the 
petitioner contained conclusions and assessments to support its 
conclusions that the petition complied with FQPA elements set forth in 
section 408(d)(3) of the FFDCA.
    There were no comments received in response to the notice of 
filing.

I. Statutory Background

    Section 408 of the Federal Food, Drug, and Cosmetic Act (FFDCA), 21 
U.S.C. 301 et seq., as amended by the Food Quality Protection Act of 
1996, (FQPA) Pub. L. 104-170) authorizes the establishment of 
tolerances (maximum residue levels), exemptions from the requirement of 
a tolerance, modifications in tolerances, and revocation of tolerances 
for residues of pesticide chemicals in or on food commodities and 
processed foods. Without a tolerance or exemption, food containing 
pesticide residues is considered to be unsafe and therefore 
``adulterated'' under section 402(a) of the FFDCA, and hence may not 
legally be moved in interstate commerce. For a pesticide to be sold and 
distributed, the pesticide must not only have appropriate tolerances 
under the FFDCA, but also must be registered under section 3 of the 
Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA, 7 U.S.C. 
136 et seq.).
    Section 408 was substantially amended by the FQPA. Among other 
things, the FQPA amends the FFDCA to bring all EPA pesticide tolerance-
setting activities under a new section 408 with a new safety standard 
and new procedures. New section 408(b)(2)(A)(i) 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 food, drinking water, and from pesticide use 
in gardens, lawns, or buildings (residential and other indoor uses) 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....''

II. Risk Assessment and Statutory Findings -- Background

    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. For many 
of these 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 the studies have 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

[[Page 26956]]

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. 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 by EPA to pose a reasonable 
certainty of no harm. For threshold effects other than those assessed 
under the RfD, EPA generally calculates a margin of exposure (MOE). The 
MOE is a measure of how close the exposure comes to the NOEL. The NOEL 
is selected from a study of appropriate duration and route of exposure. 
The MOE is the NOEL from the selected study divided by exposure. MOEs 
greater than 100 are generally considered to show a reasonable 
certainty of no harm.
    Lifetime feeding studies in two species of laboratory animals are 
conducted to screen pesticides for cancer effects. When evidence of 
increased cancer is noted in these studies, the Agency conducts a 
weight of the evidence review of all relevant toxicological data 
including short term and mutagenicity studies and structure activity 
relationship. Once a pesticide has been classified as a potential human 
carcinogen, different types of risk assessments (e.g., linear low dose 
extrapolations or margin of exposure calculation based on the 
appropriate NOEL) will be carried out based on the nature of the 
carcinogenic response and the Agency's knowledge of its mode of action.
    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, and other non-
occupational exposures, such as where residues leach into groundwater 
or surface water that is consumed as drinking water and exposures 
resulting from indoor and outdoor residential 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. The TMRC is a 
``worst case'' estimate since it is based on the assumptions that food 
contains pesticide residues at the tolerance level and that 100 percent 
of the crop is treated by pesticides that have established tolerances. 
If the TMRC exceeds the RfD or poses a lifetime cancer risk that is 
greater than approximately one in a million, EPA attempts to derive a 
more accurate exposure estimate for the pesticide by evaluating 
additional types of information which show, generally, that pesticide 
residues in most foods when they are eaten are well below established 
tolerances.
    Consistent with sections 408(b)(2)(D), EPA has reviewed the 
available scientific data and other relevant information in support of 
this action. EPA has also assessed the toxicology database for 
pyridaben in its evaluation of application for registration on citrus, 
apples, pears and almonds. EPA has sufficient data to assess the 
hazards of pyridaben and to make a determination on aggregate exposure, 
consistent with section 408(b)(2), for granting time-limited tolerances 
for residues of pyridaben on apples at 0.6 ppm, wet apple pomace at 1.0 
ppm, pears at 0.75 ppm, citrus at 0.5 ppm, dried citrus pulp at 1.5 
ppm, citrus oil at 10.0 ppm, milk at 0.01 ppm, meat at 0.05 ppm, meat 
by-products at 0.05 ppm, fat at 0.05 ppm, almonds at 0.05 ppm, almond 
hulls at 4.0 ppm. EPA's assessment of the database, dietary exposures 
and risks associated with establishing these tolerances follows.

III. Toxicology Database

    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 pyridaben are 
discussed below.
    1. A battery of acute toxicity studies placing technical pyridaben 
in toxicity category II for acute oral toxicity and category III and IV 
for the remaining studies.
    2. Pyridaben was administered in the diet to CD rats at dosages of 
0, 30, 65, 155 and 350 ppm for 13 weeks. The NOEL was determined to be 
65 ppm (4.94 mg/kg/day) for males; 30 ppm (2.64 mg/kg/day) for females. 
The lowest observed effect level (LOEL) was determined to be 155 ppm 
(11.55 mg/kg/day) for males based on reduced body weight gain, food 
consumption, food efficiency and altered clinical pathology parameters; 
65 ppm (5.53 mg/kg/day) for females based on reduced body weight gain 
and food efficiency.
    3. In a 13 week feeding study in dogs, Pyridaben was administered 
in capsules to beagle dogs at dosages of 0, 0.5, 1.0, 4.0 or 16.0 mg/
kg/day. The NOEL was 1.0 mg/kg/day for males and females and the LOEL 
was 4.0 mg/kg/day for males and females based on an increased incidence 
of clinical signs and decreased body weight gain.
    4. In a 21 day dermal study, rats received repeated topical 
applications of pyridaben to about 10% of the body surface area at 
dosages of 30, 100, 300 and 1,000 mg/kg for 21 days produced body 
weight decreases in the 300 mg/kg/day females and in the 1,000 mg/kg/
day males and females. The NOEL was 100 mg/kg/day and the LOEL was 300 
mg/kg/day based on decreased body weight gain in females.
    5. In a 12-month chronic feeding study in dogs pyridaben was 
administered in capsules at dosages of 0, 1.0, 4.0, 16.0 or 32.0 mg/kg/
day. The NOEL was determined to be < 1.0 mg/kg/day and the LOEL was 
 1.0 mg/kg/day based on increased incidence of clinical 
signs in both sexes and decreased body weight gain in females at 1.0 
mg/kg/day.
    6. Pyridaben was administered in capsules to beagle dogs at dosages 
of 0 and 0.5 mg/kg/day for 1 year. The NOEL was determined to be < 0.5 
mg/kg/day for males and females and the LOEL was  0.5 mg/kg/
day for males and females based on an increased incidence of clinical 
signs in both treated sexes and decreased weight gain in the treated 
females.
    7. Pyridaben was administered in the diet to CD-1 mice at dosages 
of 0, 2.5, 8.0, 25 or 80 ppm for 78 weeks. There was no evidence of a 
carcinogenic effect of the chemical. The NOEL was determined to be 25 
ppm (2.78 mg/kg/day) for males and females and a LOEL of 80 ppm (8.88 
and 9.74 mg/kg/day for males and females, respectively). The MTD was 
determined to be 80 ppm for males and females based on decreased body 
weight gain, decreased food efficiency and changes in organ weights and 
histopathology (males).
    8. Pyridaben was administered in the diet to groups of Wistar rats 
for 104 weeks at doses of 0, 4, 10, 28 or 80 ppm to assess 
carcinogenicity. Additional groups received doses of 0, 4, 10, 28 or

[[Page 26957]]

120 ppm for 104 weeks (with an interim sacrifice at 53 weeks) to assess 
chronic toxicity. There was no treatment-related neoplastic or non-
neoplastic pathology in either phases of the study. The NOEL was 
determined to be 28 ppm in males (1.13 mg/kg/day) and 28 ppm (1.46 mg/
kg/day) in females. The LOEL was determined to be 120 ppm (5.00 mg/kg/
day) in males and 120 ppm (6.52 mg/kg/day) in females based on 
decreased body weight gain in males and females and decreased ALT 
levels in males in the chronic toxicity phase. There was no evidence of 
a carcinogenic effect of this chemical.
    9. Pyridaben was administered to female Sprague-Dawley rats from 
days 6 through 15 of gestation at dosages of 0, 2.5, 5.7, 13.0 or 30.0 
mg/kg/day. Maternal toxicity was evidenced by decreased body weight/
body weight gain and food consumption in the 13 and 30 mg/kg/day 
groups. The Maternal NOEL is 4.7 mg/kg/day (82% of 5.7 mg/kg/day); The 
Maternal LOEL is 13.0 mg/kg/day based on decreased body weight/weight 
gain and food consumption during the dosing period. The Developmental 
NOEL is 13.0 mg/kg/day; a Developmental LOEL of 30 mg/kg/day based on 
decreased fetal body weight and increased incomplete ossification in 
selected bones.
    10. A study was performed in Himalayan rabbits in which the test 
compound was administered to groups of female pregnant rabbits by 
dermal application at dose levels of 0, 70, 170, or 450 mg/kg/day from 
gestational days 6 to 19, inclusive. The Maternal toxicity, observed at 
70 mg/kg/day, was manifested by moderate to severe skin reactions. At 
``170 mg/kg/day, there was body weight loss and food consumption and 
moderate to severe skin reactions in 50% of the animals. In addition, 
the severity of skin reactions increased in a time-and dose-dependent 
manner. The maternal systemic NOEL is 70 mg/kg/day. Developmental 
toxicity observed at 450 mg/kg/day (HDT) consisted of increase in the 
incidence of fetuses with incompletely ossified skull. The 
developmental NOEL was 170 mg/kg/day.
    11. New Zealand white rabbits were dosed with 0, 1.5, 5, or 15 mg/
kg/day pyridaben from day 6 through 19 of gestation. Maternal toxicity 
was evidenced by a dose-dependent decrease in body weight gain and food 
consumption at al dose levels. There was also increase incidence of 
abortions and clinical signs (few feces) in the 15 mg/kg/day group. 
There was no evidence that the chemical had a developmental effect at 
any of the tested levels. the maternal NOEL was < 1.5 mg/kg/day and the 
Maternal LOEL was < 1.5 mg/kg/day based on decreases in body weight 
gain and food consumption at all dose levels. The developmental NOEL 
was > 15 mg/kg/day and the Developmental LOEL was > 15 mg/kg/day.
    12. In a standard two-generation reproduction study, CD rats were 
administered pyridaben in the diet at doses of 0, 10, 28 or 80 ppm. 
There was no effect on reproductive parameters on the dose levels 
tested. The Parental/Systemic NOEL is 28 ppm (2.20 and 2.41 mg/kg/day 
for males and females, respectively). The parental/systemic LOEL is 80 
ppm (6.31 and 7.82 mg/kg/day for males and females, respectively) based 
on decreased body weights, body weight gains and food efficiency. The 
reproductive NOEL is  80 ppm in males and females. The 
reproductive LOEL is > 80 ppm in males and females.
    13. Mutagenicity studies including Ames testing, in vitro 
cytogenicity (chinese hamster lung cell), in vivo micronucleus assay 
(mouse) and DNA damage/repair (E. coli) showed no mutagenic activity 
associated with pyridaben.
    14. In an acute neurotoxicity study, rats were dosed once with 0, 
50, 100 and 200 mg/kg body weight (active ingredient equivalents: 44.3, 
79.6, and 190 mg/kg for males and 0, 44.5, 99.7, and 190 mg/kg body 
weight for females). The animals were observed for mortality and 
clinical signs of toxicity for 14 days post-dosing. No treatment 
related gross or microscopic neuropathologic findings were present. The 
NOEL for systemic toxicity is 50 mg/kg/day in both sexes. The LOEL for 
systemic toxicity is 100 mg/kg in males and females based on the 
clinical signs of toxicity, and decreased food consumption and body 
weight gain. Based on the findings of this study (screening battery), 
the LOEL for neurobehavioral effects was established at 200 mg/kg in 
males (FOB findings and motor activity); no LOEL was established for 
females (>HDT).
    15. In a subchronic neurotoxicity study pyridaben was administered 
to CD rats at dietary levels of 0, 30, 100, and 350 ppm (0, 2.5, 8.5 
and 28.8 mg/kg/day in males and 0, 2.8, 9.3 and 31.1 mg/kg/day in 
females, respectively) for 13 weeks. No neuropathological effects were 
observed. The LOEL was established at 350 ppm (28.8 mg/kg/day in males 
and 31.1 mg/kg/day in females). The NOEL was established at 100 ppm 
(8.5 mg/kg/day in males and 9.3 mg/kg/day in females.

B. Toxicology Profile

    1. Toxicity endpoint for dietary exposure--i. Chronic effects. A 
reference dose (RfD) has been estimated for pyridaben at 0.005 mg/kg/
day based on a NOEL of 0.5 mg/kg/day (lowest dose tested) observed in a 
1 year dog study for body weight gain reduction. An uncertainty factor 
of 100 was utilized to account for both interspecies and intraspecies 
variability.
    ii. Acute toxicity. To assess acute dietary exposure, the Agency 
used a toxicity endpoint of 50 mg/kg/day, the NOEL for the acute oral 
neurotoxicity study in rats.
    iii. Carcinogenicity. Based on the available carcinogenicity 
studies in two rodent species, the Agency has classified pyridaben as a 
Group ``E'' for carcinogenicity (no evidence of carcinogenicity). There 
was no evidence of carcinogenicity in an 18-month feeding study in mice 
and a 2-year feeding study in rats at the dose levels tested.
    2. Toxicity endpoints for non-dietary exposure--i. short- and 
intermediate-term risk. As part of the hazard assessment process, the 
Agency reviews the available toxicological database to determine the 
endpoints of concern. For pyridaben, the Agency does not have a concern 
for a short-term or intermediate-term assessment since the available 
data do not indicate any evidence of significant toxicity by the dermal 
or inhalation routes. Therefore, a short-term or intermediate-term 
assessment was not required. Since there are no residential uses or 
exposure, a residential risk assessment is not required.
    ii. Chronic non-dietary exposure. As part of the hazard assessment 
process an endpoint of concern was determined for the chronic non-
dietary assessment. However, during the exposure assessment process, 
the exposures which would result from the use of pyridaben was 
determined to be of an intermittent nature. The frequency and duration 
of these exposures do not exhibit a chronic exposure pattern. The 
exposures do not occur often enough to be considered a chronic exposure 
i.e., a continuous exposure that occurs for at least several months. 
Therefore, a chronic occupational assessment was not required.

C. Aggregate Exposure

    1. Food and feed uses. For purposes of assessing the potential 
chronic dietary exposure from the use of pyridaben on citrus, apples, 
almonds and pears, EPA has estimated aggregate exposure based on 
Anticipated Residue Contribution (ARC). For plant commodities, 
anticipated residue levels were calculated from field trials conducted 
at the maximum proposed

[[Page 26958]]

use rate and minimum pre-harvest interval (PHI), and the ratio of 
organosoluble residues to pyridaben residues. The ARC for processed 
commodities was based upon the average residue level for that commodity 
from field trials conducted at the maximum proposed use rate and 
minimum PHI, the ratio of organosoluble residues to pyridaben residues, 
and the concentration factor for the processed commodity. In some 
cases, adjustments for degradation of residues prior to analysis was 
taken into account. Anticipated residue levels were utilized for 
livestock feedstuffs to determine the dietary burden for ruminants, as 
well as for ruminant edible commodities. The proposed pyridaben 
tolerances result in an ARC that is up to 74 percent of the reference 
dose for the most sensitive subpopulation. The general population is 
11.8 percent of the RfD.
    The endpoint for acute dietary risk assessment is the NOEL (50 mg/
kg/day) from an acute oral neurotoxicity study in rats. The effects at 
the LOEL of 100 mg/kg/day were clinical signs of toxicity, and a 
decrease in food consumption and body weight gain. The DRES detailed 
acute analysis estimates the distribution of a singe -day exposure for 
the overall U.S. population and certain subgroups. For acute dietary 
risk for the population subgroup with the highest exposure, non-nursing 
infants (<1 year), the estimated margin of exposure (MOE) is 1,250. The 
margin of exposure (MOE) is a measure of how close the high end 
exposure comes to the LOEL and is calculated as the ratio of the NOEL 
to the exposure (NOEL/exposure = MOE). Generally, acute dietary margins 
of exposure greater than 100 tend to cause no dietary concern. The 
Agency considers the acute and chronic dietary risks to be acceptable.
    In conducting this exposure assessment, EPA has made conservative 
assumptions-- 100 percent of the apples, citrus, almonds and pears will 
contain pyridaben residues. This will result in an overestimate of 
human exposure.
    2. Potable water. The Agency does not have drinking water 
monitoring data available to perform a quantitative drinking water risk 
assessment for pyridaben at this time. Based on the available 
environmental fate data, conservative estimates produced by the Generic 
Expected Environmental Concentration (GENEEC) model and Leaching Index, 
environmental concentrations of pyridaben in surface water and the 
leaching potential of pyridaben have been derived. Pyridaben has been 
assessed as immobile and thus unlikely to leach to groundwater. For 
surface water, the GENEEC model estimates body-weight based on chronic 
exposure values for pyridaben to be 9.7  x  10-7 mg/kg/day 
for the whole U.S. population and 1.8  x  10-6 mg/kg/day for 
non-nursing infants (< 1 year). These values represent < 0.1% of the 
RfD. As GENEEC is a conservative screening tool and the exposure 
estimates for both adults and children are well below 1% of the RfD, 
the Agency concludes that the potential for chronic dietary exposure 
through drinking water in insignificant.
    3. Non-dietary uses. EPA has not estimated non-dietary exposure for 
pyridaben since there are no chronic or acute residential risks 
expected from the citrus, apple, pear and almond uses. The only other 
registered use is limited to commercial greenhouse for non-food 
ornamental plants. The potential for non-occupational exposure to the 
general population is, thus, not expected to be significant.
    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.'' While 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 in a 
meaningful way, EPA is commencing a pilot process to study this issue 
further through the examination of particular classes of pesticides. 
The Agency hopes the results of this pilot process will enable it to 
apply common mechanism issues to its pesticide risk assessments. At 
present, however, the Agency does not know how to apply the information 
in its files concerning common mechanism issues to risk assessments, 
and therefore believes that in most cases, there is no available 
information concerning mechanism that can be scientifically applied to 
tolerance decisions. Where it is clear that a particular pesticide may 
share a significant common mechanism with other chemicals, a tolerance 
decision may be affected by common mechanism issues. The Agency expects 
that most tolerance decisions will fall into the area in between, where 
EPA can not reasonably determine whether a pesticide does or does not 
share a common mechanism of toxicity with other chemicals (and, if so, 
how that common mechanism should be factored into a risk assessment). 
In such circumstances, the Agency will reach a tolerance decision based 
on the best, currently available and useable information, without 
regard to common mechanism issues. However, the Agency will also 
revisit such decisions when the Agency learns how to apply common 
mechanism information to pesticide risk assessments.
    In the case of pyridaben, it is structurally similar to other 
members of the pyridazinone class of pesticides (i.e. pyrazon and 
norflurazon). However, since EPA has determined that it does not now 
have the capability to apply the information in its files to a 
resolution of common mechanism issues in a manner that would be useful 
in a risk assessment, this tolerance determination does not take into 
account common mechanism issues. The Agency will reexamine the 
tolerance for pyridaben, if reexamination is appropriate, after the 
Agency has determined how to apply common mechanism issues to its 
pesticide risk assessments.

IV. Determination of Safety for Infants and Children

    FFDCA section 408 provides that EPA shall apply an additional 
tenfold margin of safety for infants and children in the case of 
threshold effects to account for pre-and post-natal toxicity and the 
completeness of the database unless EPA determines that a different 
margin of safety will be safe for infants and children. Margins of 
safety are incorporated into EPA risk assessments either directly 
through use of a margin of exposure analysis or through using 
uncertainty (safety) factors in calculating a dose level that poses no 
appreciable risk to humans. In either case, EPA generally defines the 
level of appreciable risk as exposure that is greater than 1/100 of the 
no observed effect level in the animal study appropriate to the 
particular risk assessment. This hundredfold uncertainty (safety) 
factor/margin of exposure (safety) is designed to account for combined 
inter-and intra-species variability. EPA believes that reliable data 
support using the standard hundredfold margin/factor not the additional 
tenfold margin/factor when EPA has a complete data base under existing 
guidelines and when the severity of the effect in infants or children 
or the potency or unusual toxic properties of a compound do not raise 
concerns regarding the adequacy of the standard margin/factor.
    In assessing the potential for risk to infants and children to 
residues of pyridaben, EPA considered data from oral developmental 
toxicity studies in the rat and rabbit, as well as data from

[[Page 26959]]

a 2-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 the mothers. Reproduction studies provide information 
relating to effects from exposure to the pesticide on the reproductive 
capability of mating animals and data on systemic toxicity.
    Based on current data requirements, the database relative to pre-
and post natal toxicity is complete. These data taken together suggest 
minimal concern for developmental or reproductive toxicity and do not 
indicate any increased pre- or post-natal sensitivity. Therefore, EPA 
concludes that reliable data support use of a hundredfold safety factor 
and an additional tenfold safety factor is not needed to protect the 
safety of infants and children. Therefore, no outstanding data 
requirements exist.

V. Determination of Safety for U.S. Population Including Infants 
and Children

    1. Chronic dietary exposure/risk. A chronic dietary exposure/risk 
assessment was performed for pyridaben using a RfD of 0.005 mg/kg/day. 
Using the exposure assumptions previously described, and based on the 
completeness and reliability of the toxicity data base, EPA has 
concluded that aggregate exposure to pyridaben from its us on apples, 
pears, citrus and almonds will utilize 11.8 percent of the RfD for the 
general population and 74% for non-nursing infants < 1 year old which 
is the most exposed subpopulation. EPA generally has no concern for 
exposures below 100 percent of the RfD because the RfD represents the 
level at or below which daily aggregate dietary exposure over a 
lifetime will not pose an appreciable risk to human health.
    2. Aggregate risks. Based upon the available data and assumptions 
used for dietary and water exposure and risk estimates, the population 
group estimated to be the most highly exposed to pyridaben is non-
nursing infants (< 1 year old), with a risk estimate from combined 
sources equaling 74 percent of the RfD. (Dietary exposure contributes 
74% of the RfD and drinking water contributes less than 1% of the RfD). 
EPA therefore concludes that there is reasonable certainty that no harm 
will result to Consumers, including infants and children from aggregate 
exposure of pyridaben residues.

VI. Other Considerations

A. Endocrine Effects

    No evidence of such effects were reported in the toxicology studies 
described above. There is no evidence at this time that pyridaben 
causes endocrine effects.

B. Metabolism in Plants and Animals

    The metabolism of pyridaben in plants and animals is adequately 
understood for the purpose of this tolerance. There are no Codex 
maximum residue levels established for residues of pyridaben on the 
proposed commodities. There is a practical analytical method available 
for determination of residues of pyridaben. Adequate enforcement 
methodology (gas chromatography/electron capture detector) for plant 
and animal commodities is available to enforce the tolerances. As a 
condition of registration, EPA has requested that revisions and 
clarifications be made to the submitted methodology, and that the 
animal commodity method be improved. Once this method has been 
submitted, EPA will provide information on this method to FDA. In the 
interim, the analytical method is available to anyone who is interested 
in pesticide residue enforcement from: By mail, Calvin Furlow, 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. Office 
location and telephone number: Crystal Mall #2, Rm 1128, 1921 Jefferson 
Davis Hwy., Arlington, VA 703-305-5805.

VII. Summary of Findings

    Tolerances are time limited to allow for development and review of 
additional residue field trials, long term storage stability studies, 
and revised analytical enforcement methodology. The analysis for 
pyridaben using anticipated residue levels shows that the proposed uses 
will not cause exposure to exceed the levels at which EPA believes 
there is an appreciable risk. All population subgroups examined by EPA 
are exposed to pyridaben residues at levels below 100 percent of the 
RfD for chronic effects. Based on the information and data considered, 
EPA concludes that the proposed time-limited tolerances will be safe. 
Therefore the tolerances are established as set forth in this document.

VIII. 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 
the new section 408(d) 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 its current procedural regulations with appropriate adjustments to 
reflect the new law.
    Any person may, by July 15, 1997, file written objections to any 
aspect of this regulation and may also request a hearing on those 
objections. Objections and hearing requests must be filed with the 
Hearing Clerk, at the address given above (40 CFR 178.20). A copy of 
the objections and/or hearing requests filed with the Hearing Clerk 
should be submitted to the OPP docket for this rulemaking. The 
objections submitted must specify the provisions of the regulation 
deemed objectionable and the grounds for the objections (40 CFR 
178.25). Each objection must be accompanied by the fee prescribed by 40 
CFR 180.33(i). If a hearing is requested, the objections must include a 
statement of the factual issues on which a hearing is requested, the 
requestor's contentions on such issues, and a summary of any evidence 
relied upon by the requestor (40 CFR 178.27). A request for a hearing 
will be granted if the Administrator determines that the material 
submitted shows the following: There is genuine and substantial issue 
of fact; there is a reasonable possibility that available evidence 
identified by the requestor would, if established, resolve one or more 
of such issues in favor of the requestor, taking into account 
uncontested claims or facts to the contrary; and resolution of the 
factual issues in the manner sought by the requestor would be adequate 
to justify the action requested (40 CFR 178.32). Information submitted 
in connection with an objection or hearing request may be claimed 
confidential by marking any part or all of that information as CBI. 
Information so marked will not be disclosed except in accordance with 
procedures set forth in 40 CFR part 2. A copy of the information that 
does not contain CBI must be submitted for inclusion in the public 
record. Information not marked confidential

[[Page 26960]]

may be disclosed publicly by EPA without prior notice.

IX. Public Docket

    The official record for this rulemaking, as well as the public 
version, has been established for this rulemaking under docket control 
number [OPP-300492] (including comments and data submitted 
electronically as described below). A public version of this record, 
including printed, paper versions of electronic comments, which does 
not include any information claimed as CBI, is available for inspection 
from 8:30 a.m. to 4 p.m., Monday through Friday, excluding legal 
holidays. The official rulemaking record is located at the address in 
``ADDRESSES'' at the beginning of this document.
    Electronic comments can 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. Comment and data 
will also be accepted on disks in Wordperfect 5.1 file format or ASCII 
file format. All comments and data in electronic form must be 
identified by the docket control number [OPP-300492]. Electronic 
comments on this proposed rule may be filed online at many Federal 
Depository Libraries.

X. Regulatory Assessment Requirements

     Under Executive Order 12866 (58 FR 51735, October 4, 1993), this 
action is not a ``significant regulatory action'' and, since this 
action does not impose any information collection requirements as 
defined by the Paperwork Reduction Act, 44 U.S.C. 3501 et seq., it is 
not subject to review by the Office of Management and Budget. In 
addition, this action does not impose any enforceable duty or contain 
any unfunded mandate as described in the Unfunded Mandates Reform Act 
of 1995 (Pub. L. 104-4), or require prior consultation with State 
officials as specified by Executive Order 12875 (58 FR 58093, October 
28, 1993), or special considerations as required by Executive Order 
12898 (59 FR 7629, February 16, 1994).
    Because tolerance established on the basis of a petition under 
section 408(d) of FFDCA do not require issuance of a proposed rule, the 
regulatory flexibility analysis requirements of the Regulatory 
Flexibility Act (RFA), 5 U.S.C. 604(a), do not apply. Prior to the 
recent amendment of the FFDCA, EPA had treated such rulemakings as 
subject to the RFA; however, the amendments to the FFDCA clarify that 
no proposal is required for such rulemakings and hence that the RFA is 
inapplicable. Nonetheless, the Agency has previously assessed whether 
establishing tolerances or exemptions from tolerance, raising tolerance 
levels, or expanding exemptions adversely impact small entities and 
concluded, as a generic matter, that there is no adverse impact. (46 FR 
24950, May 4, 1981).
    Under 5 U.S.C. 801(a)(1)(A) of the Administrative Procedure Act 
(APA) as amended by the Small Business Regulatory Enforcement Fairness 
Act of 1996 (Title II of Pub. L. 104-121, 110 Stat. 847), EPA submitted 
a report containing this rule and other required information to the 
U.S. Senate, the U.S. House of Representatives and the Comptroller 
General of the General Accounting Office prior to publication of the 
rule in today's Federal Register. This rule is not a ``major rule'' as 
defined by 5 U.S.C. 804(2) of the APA as amended.

 List of Subjects in 40 CFR Part 180

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

    Dated: May 7, 1997.

Stephen L. Johnson,

Acting Director, Office of Pesticide Programs.
    Therefore, 40 CFR Chapter I is amended as follows:

PART 180-- [AMENDED]

    1. In part 180:
    a. The statutory authority for part 180 continues to read as 
follows:
    Authority: 21 U.S.C. 346a and 371.

    b. By revising Sec. 180.494 to read as follows:


Sec. 180.494   Pyridaben; tolerance for residues.

    (a) General. Time limited tolerances are established for residues 
of the insecticide pyridaben [2-tert-butyl-5-(4-tert-butylbenzylthio)-
4-chloropyridazin-3(2H)-one] on the following plants, and of the 
insecticide pyridaben and its metabolites (2-tert-butyl-5-[4-(1-
carboxy-1-methylethyl)benzylthio]-4-chloropyridazin-3(2H)-one) and (2-
tert-butyl-4-chloro-5-[4-(1,1-dimethyl-2-hydroxyethyl)benzylthio]-
chloropyridazin-3(2H)-one) on animals, as indicated in the following 
table. The tolerances will expire and are revoked on the dates 
specified in the following table.

------------------------------------------------------------------------
                                               Parts                    
                  Commodity                     per       Expiration/   
                                              million   Revocation Date 
------------------------------------------------------------------------
Almonds.....................................    0.05        5/31/2001   
Almond hulls................................    4.0           do.       
Apple.......................................    0.6           do.       
Apple pomace, wet...........................    1.0           do.       
Cattle, fat.................................    0.05          do.       
Cattle, meat................................    0.05          do.       
Cattle, meat by-products....................    0.05          do.       
Citrus......................................    0.5           do.       
Citrus oil..................................   10.0           do.       
Citrus pulp, dried..........................    1.5           do.       
Goat, fat...................................    0.05          do.       
Goat, meat..................................    0.05          do.       
Goat, meat by-products......................    0.05          do.       
Hog, fat....................................    0.05          do.       
Hog, meat...................................    0.05          do.       
Hog, meat by-products.......................    0.05          do.       
Horse, fat..................................    0.05          do.       
Horse, meat.................................    0.05          do.       
Horse, meat by-products.....................    0.05          do.       
Milk........................................    0.01          do.       
Pears.......................................    0.75          do.       
Sheep, fat..................................    0.05          do.       
Sheep, meat.................................    0.05          do.       
Sheep, meat by-products.....................    0.05          do.       
------------------------------------------------------------------------

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

[FR Doc. 97-12912 Filed 5-15-97; 8:45 am]
BILLING CODE 6560-50-F