[Federal Register Volume 62, Number 80 (Friday, April 25, 1997)]
[Rules and Regulations]
[Pages 20117-20123]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-10725]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 180, 185, and 186

[OPP-300468; FRL-5599-5]
RIN 2070-AB78


Imidacloprid; Pesticide Tolerance

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: This document extends the effective date for the established 
time-limited tolerance for residues of the insecticide imidacloprid and 
its metabolites resulting from crop rotational practices in or on the 
food commodities of the cucurbit vegetables crop group. The 
Interregional Research Project (IR-4) requested this time extension 
under the Federal Food, Drug and Cosmectic Act, as amended by the Food 
Quality Protection Act of 1966.

DATES: This regulation is effective April 25, 1997. Submit written 
objections and hearing requests on or before June 24, 1997.

ADDRESSES: Written objections and hearing requests, identified by the 
document control number, [OPP-300468; PP-5E4598], may be submitted to: 
Hearing Clerk (1900), Environmental Protection Agency, Room 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 should be identified by the document control number and 
submitted to: Public Response and Program Resources Branch, Field 
Operations Division (7506C), Office of Pesticide Programs, 
Environmental Protection Agency, 401 M St., SW., Washington, DC 20460. 
In person, bring a copy of the objections and hearing requests to: 
Crystal Mall #2, Rm. 1132, 1921 Jefferson Davis Highway, Arlington, VA.
    A copy of objections and hearing requests filed with the Hearing 
Clerk may also be submitted electronically to the OPP 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 in 5.1 file format or ASCII file format. All 
copies of objections and hearing requests in electronic form must be 
identified by the document control number [OPP-300468; PP-5E4598]. 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. 
Additional information on electronic submissions can be found in Unit 
III. of this document.

FOR FURTHER INFORMATION CONTACT: By mail: Hoyt L. Jamerson, 
Registration Division (7505W), Office of Pesticide Programs, 
Environmental Protection

[[Page 20118]]

Agency, 401 M St., SW., Washington, DC 20460. Office location, 
telephone number, and e-mail: Crystal Station #1, Sixth Floor, 2800 
Jefferson Davis Highway, Arlington, VA, 703-308-8783, e-mail: 
[email protected].
SUPPLEMENTARY INFORMATION: In the Federal Register of January 22, 1997, 
FRL-5583-3 (62 FR 3288), EPA issued a notice pursuant to section 408 of 
the Federal Food, Drug, and Cosmetic Act (FFDCA), 21 U.S.C. 346a, 
announcing the filing of an amendment to pesticide petition (PP-5E4598) 
for tolerance by the Interregional Research Project No. 4 (IR-4), New 
Jersey Agricultural Experiment Station, P.O. Box 231, Rutgers 
University, New Brunswick, NJ 08903. That notice included a summary of 
the petition prepared by Bayer Corporation, the registrant. There were 
no comments received in response to the notice of filing. The amended 
petition requested that 40 CFR 180.472 be amended by extending the 
effective date to expire on December 31, 1997, for the time-limited 
tolerance established for the indirect or inadvertent combined residues 
of the insecticide imidacloprid (1-[(6-chloro-3-pyridinyl)methyl]-N-
nitro-2-imidazolidinimine) and its metabolites containing the 6-
chloropyridinyl moiety, all expressed as 1-[(6-chloro-3-
pyridinyl)methyl]-N-nitro-2-imidazolidinimine, resulting from crop 
rotational practices in or on the food commodities in the cucurbit 
vegetables crop group at 0.2 parts per million (ppm).
    This tolerance will not support registration for imidacloprid on 
cucurbit vegetables. EPA will not consider applications for section 3 
or section 24(c) registration for use of imidacloprid on cucurbit 
vegetables based on this time-limited tolerance. The tolerance will 
allow growers to produce cucurbit vegetables in rotation with crops 
that are treated in accordance with registered uses of imidacloprid. 
Imidacloprid registrations prohibit growers from planting crops that 
lack an imidacloprid tolerance on ground treated with the insecticide 
within a 12-month period. Crop rotational studies indicate that plant 
back crops grown in fields treated with imidacloprid may contain 
measurable amounts of the pesticide residue, if the rotational crop is 
planted within 12 months of application of the pesticide. In some 
areas, however, it is a common practice for growers to plant back 
cucurbit vegetables (melons, squash, and cucumbers) in fields that have 
been used to produce tomatoes and peppers. Imidacloprid is registered 
and tolerances are established for the fruiting vegetables crop group 
(including tomatoes and peppers).
    IR-4 has submitted PP-6E4766, which proposes a permanent tolerance 
for residues of imidacloprid and its metabolites in or on the cucurbit 
vegetables crop group at 0.5 ppm. Although PP-6E4766 proposes a 
tolerance in support of registration for use of imidacloprid on 
cucurbit vegetables, the proposed tolerance, if established, will be 
adequate to cover indirect or inadvertent residues on cucurbits 
resulting from registered uses of imidacloprid. EPA's evaluation of PP-
6E4766 was not completed in time to establish a permanent tolerance, 
prior to the December 31, 1996, expiration date for the time-limited 
tolerance. Therefore, EPA is extending the effective date for the time-
limited tolerance for imidacloprid to expire December 31, 1997, to 
allow EPA additional time to review IR-4's petition for permanent 
tolerance for residues of imidacloprid on cucurbit vegetables.
    In addition to the new tolerance being established, since for 
purposes of establishing tolerances the Food Quality Protection Act 
(FQPA), Pub. L. 104-170, has eliminated all distinctions between raw 
and processed food, EPA is combining the tolerances that now appear in 
Sec. Sec. 185.900 and 186.900 with the tolerances in Sec. 180.472 and 
is eliminating Sec. Sec. 185.900 and 186.900

I. Determination of Safety

    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) of the FFDCA 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, but does 
not include occupational exposure. Section 408(b)(2)(C) of the FFDCA 
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....''

A. Method of Determining Risks

    1. 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 assumption that 
food contains pesticide residues at the tolerance level and that 100% 
of the crop is treated by pesticides that have established tolerances. 
If the TMRC exceeds the reference dose (RfD) or poses a lifetime cancer 
risk that is greater than approximately 1 in 1 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 and that the total acreages for all crops with 
established tolerances are seldom treated with the pesticide.
    2. The RfD is assumed to be the exposure at or below which daily 
aggregate exposure over a lifetime will not pose an appreciable risk to 
human health. To assure the adequacy of the RfD, the Agency uses an 
uncertainty factor in deriving it. The factor is usually 100, based on 
the assumption that certain segments of the human population could be 
as much as 100 times more sensitive than the species represented by the 
toxicology data. The aggregate daily exposure to a pesticide residue at 
or below the RfD (expressed as l00% of the RfD) is generally considered 
acceptable by EPA.
    3. Lifetime feeding studies in two species of laboratory animals 
are conducted to screen pesticides for cancer effects. If the pesticide 
is determined to be a human carcinogen, the toxicological endpoint must 
be determined based on the nature of the carcinogenic response and a 
knowledge of its mode of action. The Agency uses a weight of evidence 
approach in classifying the potential of the pesticide as a human 
carcinogen.
    4. In addition to assessing long-term, chronic exposure to 
pesticide residues in food, the Agency also evaluates single day or 
single event, acute exposure. Acute dietary exposure to residues of a 
pesticide in a food commodity is estimated by multiplying individual, 
single-day consumption estimates of that food by the tolerance level or 
the anticipated pesticide residue level. Each individual's daily 
exposure to a pesticide is the sum of the food commodities that 
individual consumed on that given day multiplied by the residue assumed 
to be present on each food commodity consumed. Using this

[[Page 20119]]

method, a distribution of possible daily exposures for a given 
population is established.
    5. From this distribution, an upper-end estimate of exposure is 
chosen and compared to the most sensitive no-observed-effect level 
(NOEL) from studies relating to the toxicological effect of acute 
concern (usually developmental toxicity or neurotoxicity) to derive a 
margin of exposure (MOE). The MOE is a measure of the level of safety 
that exists between the estimated exposure to a highly exposed 
individual and the level below which effects were observed in the 
available toxicological studies. As with chronic exposure estimates, 
residue and percent of crop treated refinements are incorporated to 
derive a more accurate exposure estimate when risks calculated using 
``worst case'' assumptions exceed risk levels of concern

B. Toxicological Study Summaries

    The toxicological data considered in support of the tolerance 
include:
    1. A 1-year chronic feeding study in dogs fed diets containing 0, 
200, 500, or 1,250/2,500 ppm (average intake was 0, 6.1, 15, or 41/72 
milligrams (mg)/kilogram (kg)/day) with a NOEL of 1,250 based on 
increased plasma cholesterol and liver cytochrome P-450 levels in dogs 
at the 2,500 ppm dose level. The high dose was increased to 2,500 ppm 
(72 mg/kg/day) from week 17 onward due to lack of toxicity at the 
1,250-dose level.
    2. A 2-year feeding/carcinogenicity study in rats fed diets 
containing 0, 100, 300, 900, or 1,800 ppm with a NOEL for chronic 
effects at 100 ppm (5.7 mg/kg/day in males, 7.6 mg/kg/day in females) 
that included decreased body weight gain in females at 300 ppm (24.9 
mg/kg/day) and above, and increased thyroid lesions in males at 300 ppm 
(16.9 mg/kg/day) and above, and in females at 900 ppm (73 mg/kg/day) 
and above. There were no apparent carcinogenic effects under the 
conditions of the study.
    3. A 2-year carcinogenicity study in mice fed diets containing 0, 
100, 330, 1,000, or 2,000 ppm with a NOEL of 1,000 ppm (208 mg/kg/day 
in males, 274 mg/kg/day in females) based on decreased food consumption 
and decreased water intake at the 2,000 ppm dose level. There were no 
apparent carcinogenic effects observed under the conditions of this 
study.
    4. A three-generation reproduction study with rats fed diets 
containing 0, 100, 250, or 700 ppm with a reproductive NOEL of 100 ppm 
(equivalent to 8 mg/kg/day based on decreased pup body weight observed 
at the 250 ppm dose level).
    5. A developmental toxicity study in rats given gavage doses at 0, 
10, 30, or 100 mg/kg/day during gestation days 6 to 16 with a NOEL for 
developmental toxicity at 30 mg/kg/day based on increased wavy ribs 
observed at the 100 mg/kg/day dose level.
     6. A developmental toxicity study in rabbits given gavage doses at 
0.8, 24, or 72 mg/kg/day during gestation days 6 through 19 with a NOEL 
for developmental toxicity at 24 mg/kg/day based on decreased body 
weight and increased skeletal abnormalities observed at the 72 mg/kg/
day dose level.
    7. Imidacloprid was negative for mutagenic effects in all but 2 of 
23 mutagenic assays. Imidacloprid tested positive for chromosome 
abberations in an in vitro cytogenic study with human lymphocytes for 
the detection of induced clastogenic effects, and for genotoxicity in 
an in vitro cytogenetic assay measuring sister chromatid exchange in 
Chinese hamster ovary cells.

C. Toxicological Endpoints

    1. Dietary--i. Chronic toxicity. The RfD for imidacloprid is 
established at 0.057 mg/kg/day. The RfD is established based on a 2-
year feeding/carcinogenicity study in rats with a NOEL of 5.7 mg/kg/day 
and an uncertainty factor of 100. The lowest-observed-effect level 
(LOEL) of 16.9 mg/kg/day is based on increased thyroid lesions in 
males.
    ii. Acute toxicity. EPA has determined that an NOEL of 24 mg/kg/day 
from a developmental toxicity study in rabbits should be used to assess 
acute toxicity. A decrease in body weight, an increases in resorptions, 
abortions, and skeletal abnormalities were observed at the LOEL of 72 
mg/kg/day. The population of concern for this risk assessment are 
females 13+ years old.
    iii. Cancer risk. Using its Guidelines for Carcinogen Risk 
Assessment published in the Federal Register on September 24, 1986 (51 
FR 33992), EPA has classified imidacloprid as a Group E carcinogen 
(``no evidence of carcinogenicity for humans''--based on the results of 
carcinogencity studies in two species). The doses tested are adequate 
for identifying a cancer risk. Thus, cancer risk assessments are not 
appropriate for imidacloprid.
    2. Non-Dietary--Short- and intermediate-term risk. No effects were 
observed at the highest dose tested (0.191 mg/liter (L) ) in a 28-day 
inhalation study in rats and no systemic toxicity was observed at dose 
levels up to 1,000 mg/kg/day in a 21-day dermal toxicity study in 
rabbits.

D. Aggregate Exposures and Risks

    1. From food and feed uses. i. Tolerances have been established (40 
CFR 180.472) for the combined residues of imidacloprid (1-[(6-chloro-3-
pyridinyl)methyl]-N-nitro-2-imidazolidinimine) and its metabolites 
containing     6-chloropyridinyl moiety expressed in or on certain food 
commodities ranging from 0.02 ppm in eggs to 3.5 ppm in Brassica 
vegetable crop group (cabbage, chinese cabbage, and kale) and head and 
leaf lettuce.
    ii. In conducting this exposure assessment, EPA has made very 
conservative assumptions--100% of cucurbits and all other commodities 
having imidacloprid tolerances will contain imidacloprid tolerances 
residues and those residues would be at the level of the tolerance--
which result in an overestimate of human dietary exposure. Thus, in 
making a safety determination for this tolerance, EPA is taking into 
account this conservative exposure assessment.
    iii. The existing imidacloprid tolerances (published, pending, and 
including the current time-limited tolerance for cucurbits) result in a 
TMRC that is equivalent to the following percentages of the RfD:

------------------------------------------------------------------------
                                                                        
------------------------------------------------------------------------
U.S Population............................  16%                         
Nursing Infants...........................  12%                         
Non-Nursing Infants (<1 year old).........  31%                         
Children (1-6 years old)..................  32%                         
Children (7-12 years old).................  24%                         
------------------------------------------------------------------------

    2. From drinking water. i. In examining aggregate exposure, FQPA, 
directs EPA to consider available information concerning exposures from 
the pesticide residue in food and all other non-occupational exposures. 
The primary non-food sources of exposure the Agency looks at include 
drinking water (whether from groundwater or surface water), and 
exposure through pesticide use in gardens, lawns, or buildings 
(residential and other indoor uses).
    ii. Based on the available studies used in EPA's assessment of 
environmental risk, imidacloprid is persistent and could potentially 
leach into groundwater, and run off to surface water under certain 
environmental conditions. There is no established maximum concentration 
level (MCL) for residues of imidacloprid in drinking water. No drinking 
water health advisories have been issued for imidacloprid. The 
``Pesticides in

[[Page 20120]]

Groundwater Database'' (EPA 734-12-92-001, September 1992) has no 
information concerning imidacloprid.
    iii. Because the Agency lacks sufficient water-related exposure 
data to complete a comprehensive drinking water risk assessment for 
many pesticides, EPA has commenced and nearly completed a process to 
identify a reasonable yet conservative bounding figure for the 
potential contribution of water related exposure to the aggregate risk 
posed by a pesticide. In developing the bounding figure, EPA estimated 
residue levels in water for a number of specific pesticides using 
various data sources. The Agency then applied the estimated residue 
levels, in conjunction with appropriate toxicological endpoints (RfD's 
or acute dietary NOEL's) and assumptions about body weight and 
consumption, to calculate, for each pesticide, the increment of 
aggregate risk contributed by consumption of contaminated water. A more 
detailed description of this analysis is included in the docket for 
this rulemaking. While EPA has not yet pinpointed the appropriate 
bounding figure for consumption of contaminated water, the ranges the 
Agency is continuing to examine are all well below the level that would 
cause imidacloprid to exceed the RfD if the tolerance being considered 
in this document were granted. The Agency has therefore concluded that 
the potential exposures associated with imidacloprid in water, even at 
the higher levels the Agency is considering as a conservative upper 
bound, would not prevent the Agency from determining that there is a 
reasonable certainty of no harm if the tolerance is granted.
    3. From non-dietary uses. i. Imidacloprid is currently registered 
for use on the following non-food sites: turf, ornamentals, buildings 
for termite control, and cats and dogs for flea control.
    ii. A residential exposure and risk assessment for imidacloprid use 
on turfgrass was recently conducted by EPA in conjunction with the 
reregistration of imidacloprid. Dermal and inhalation exposures were 
measured using volunteers who performed a choreographed exercise 
routine on a turf plot treated with imidacloprid at the maximum 
registered rate. Dermal levels were measured using whole body 
dosimetry. Using the NOEL of 1,000 mg/kg/day from the dermal toxicity 
study in rabbits, an MOE corresponding to an upper bound risk of 7,587 
was calculated for 10 year old and 6,858 for 5 year old children. 
Inhalation levels were measured using quartz microfiber filters 
connected by polyvinylchloride tubing to portable air sampling pumps. 
Specific toxicological endpoints of concern for inhalation exposure 
have not been identified by EPA. However, in the rat sub-acute 
inhalation study (28-day study in which rats were exposed 6 hours/day, 
5 days a week for 4 weeks) the no-observable-effect concentration 
(NOEC) for imidacloprid was 5.5 mg/m3. This NOEC is approximately 
800 times the concentration recorded in the immediate vicinity of the 
volunteers during the performance of their exercise routine. The 
analysis concluded that ``...risks to children are negligible from 
imidacloprid-treated turf as soon as the spray has dried.''
    iii. An exposure and risk assessment for the termiticide use of 
imidacloprid was also conducted by EPA. Conservative estimates of 
maximum air concentrations to which humans could be exposed and 
continuous exposure (24 hours per day) were assumed in calculating 
MOEs. Adult exposure was calculated at 1.24 x 10-5 mg/kg/day and 
infant exposure at 3.3 x 10-5 mg/kg/day. As noted above, specific 
toxicological endpoints of concern for inhalation exposure have not 
been identified by EPA. For calculating MOEs, the sub-acute rat 
inhalation study was used which had a NOEL of 0.191 mg/L, the highest 
dose tested (corresponding to 43.08 mg/kg/day). Based on the exposures 
and using this NOEL, MOEs of 3.4 x 106 and 1.3 x 106 were 
calculated for adults and children, respectively.
    4. Cumulative exposure to substances with common mechanism of 
toxicity. i. Section 408(b)(2)(D)(v) of the FFDCA 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.
    ii. 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).
    iii. EPA does not have, at this time, available data to determine 
whether imidacloprid has a common mechanism of toxicity with other 
substances or how to include this pesticide in a cumulative risk 
assessment. For the purposes of this tolerance action, therefore, EPA 
has not assumed that imidacloprid has a common mechanism of toxicity 
with other substances.

E. Determination of Safety for U.S. Population

    1. Chronic risk. Using the conservative exposure assumptions 
described above, taking into account the completeness and reliability 
of the toxicity data, EPA has concluded that aggregate dietary exposure 
to imidacloprid will utilize 16% of the RfD for the U.S. population. 
EPA generally has no concern for exposures below 100% of the RfD 
because the RfD represents the level at or below which daily aggregate 
dietary exposure over a lifetime will not pose appreciable risks to 
human health. Despite the potential for exposure to imidacloprid in 
drinking water, EPA does not expect the aggregate exposure to exceed 
100% of the RfD. EPA concludes that there is a reasonable certainty 
that no harm will

[[Page 20121]]

result from aggregate exposure to imidacloprid residues.
    2. Acute risk. For the population subgroup of concern, females 13+ 
and older (accounts for both maternal and fetal exposure), the 
calculated MOE value is 480. This MOE does not exceed the Agency's 
level of concern for acute dietary exposure.

F. Determination of Safety For Infants and Children

    In assessing the potential for additional sensitivity of infants 
and children to residues of imidacloprid, 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 to female test animals. 
Reproduction studies provide information relating to effects from 
exposure to the pesticide on the reproductive capability of mating 
animals and data on systemic toxicity.
    In the rat developmental study, the maternal (systemic) NOEL was 30 
mg/kg/day, based on decreased weight gain at the LOEL of 100 mg/kg/day. 
The developmental (fetal) NOEL was 30 mg/kg/day based on increased wavy 
ribs at the LOEL of 100 mg/kg/day. In the rabbit developmental study, 
the maternal (systemic) NOEL was 24 mg/kg/day, based on decreased body 
weight, increased resorptions and abortions, and death at the LOEL of 
72 mg/kg/day. The developmental (fetal) NOEL was 24 mg/kg/day, based on 
decreased body weight and increased skeletal anomalies at the LOEL of 
72 mg/kg/day.
    In the rat developmental study, the developmental (fetus) and 
maternal (mother) NOELs occur at the same dose level, 24 mg/kg/day. The 
same response is seen in the rabbit developmental study with the 
developmental (fetus) and maternal (mother) NOELs occurring at same 
dose level of 30 mg/kg/day. This suggests that there are no special 
prenatal sensitivities for unborn children in the absence of maternal 
toxicity. However, a detailed analysis of the developmental studies 
indicates that the skeletal findings (wavy ribs and other anomalies) in 
both the rat and rabbit fetuses are severe malformations which occurred 
in the presence of slight toxicity (decreases of body weight) in the 
maternal animals. Additionally, in rabbits, there were resorptions and 
abortions which can be attributed to acute maternal exposure. This 
information has been interpreted by the Toxicology Endpoint Selection 
Committee (TESC) as indicating a potential acute dietary risk for pre-
natally exposed infants.
    In the two-generation rat reproduction study, the maternal NOEL is 
55 mg/kg/day and the NOEL for decreased pup body weight during 
lactation is 8 mg/kg/day with the LOEL at 19 mg/kg/day. This study 
shows that adverse postnatal development of pups occurs at levels (19 
mg/kg/day) which are lower than the NOEL for the parental animals (55 
mg/kg/day). Therefore, the pups are more sensitive to the effects of 
imidacloprid than parental animals. The pup NOEL of 8 mg/kg/day in the 
reproduction study is 1.4 times greater than the NOEL of 5.7 from the 
2-year rat feeding study which was the basis of the RfD. The TMRC value 
for the most highly exposed infant and children subgroup (children 1-6 
years old) occupies 32% of the RfD.
    1. Chronic risk. Using the conservative exposure assumptions 
described above, EPA has concluded that the percent of the RfD that 
will be utilized by aggregate exposure to residues of imidacloprid 
ranges from 12% for nursing infants, up to 32% for children 1-6 years 
old. Therefore, taking into account the completeness and reliability of 
the toxicity data and the conservative exposure assessment, EPA 
concludes that there is a reasonable certainty that no harm will result 
to infants and children from aggregate exposure to imidacloprid 
residues.
    2. Acute risk. i. At present, the acute dietary MOE for females 13+ 
years old (accounts for both maternal and fetal exposure) is 480. This 
MOE calculation was based on the developmental NOEL in rabbits of 24 
mg/kg/day. Maternal effects observed at the lowest-effect level (LEL) 
of 72 mg/kg/day included decreased body weight and increased 
resorptions and abortions. Fetal effects observed at the LEL of 72 mg/
kg/day included an increase in skeletal abnormalities. This risk 
assessment also assumed 100% crop treated with tolerance level residues 
on all treated crops consumed, resulting in a significant over-estimate 
of dietary exposure. The large acute dietary MOE calculated for females 
13+ years old provides assurance that there is a reasonable certainty 
of no harm for both females 13+ years and the pre-natal development of 
infants.
    ii. FFDCA section 408 provides that EPA shall apply an additional 
tenfold MOE (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 MOE (safety) 
will be safe for infants and children. Margins of exposure (safety) are 
often referred to as uncertainty (safety) factors. EPA believes that 
reliable data support using the standard MOE (usually 100x for combined 
inter- and intra-species variability) and not the additional tenfold 
MOE 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. Based on current 
toxicological data requirements, the database for imidacloprid relative 
to pre- (provided by rat and rabbit developmental studies) and post-
natal (provided by the rat reproduction study) toxicity is complete. 
Further, as noted above, the acute dietary MOE for women 13+ years or 
older is 480. This large MOE demonstrates that the prenatal exposure to 
infants is not a toxicological concern at this time, and the additional 
uncertainty factor is not needed to protect the safety of infants and 
children.
    iii. Both chronic and acute dietary exposure risk assessments 
assume 100% crop treated and use tolerance level residues for all 
commodities. Refinement of these dietary risk assessments by using 
percent crop treated and anticipated residue data would greatly reduce 
dietary exposure. Therefore, both of these risk assessments are also an 
over-estimate of dietary risk. Consideration of anticipated residues 
and percent crop treated would likely result in an anticipated residue 
contribution (ARC) which would occupy a percent of the RfD that is 
likely to be significantly lower than the currently calculated TMRC 
value. Additionally, the acute dietary MOE would be greater than the 
current MOE. This provides an adequate safety factor for children 
during the prenatal and postnatal development.
    iv. It is unlikely that the dietary risk will exceed 100% of the 
RfD or that the acute MOE would be less than the currently calculated 
value if, in the future, an additional safety factor is deemed 
appropriate, when considered in conjunction with a refined exposure 
estimate. Therefore, EPA concludes that there is reasonable certainty 
that no harm will result to infants and children from aggregate 
exposure to imidacloprid residues.

G. Other Considerations

    1. Endocrine effects. An evaluation of the potential effects on the 
endocrine systems of mammals has not been determined; however, no 
evidence of such effects were reported in the

[[Page 20122]]

chronic toxicology studies described above. There were no observed 
pathology of the endocrine organs in these studies. There is no 
evidence at this time that imidocloprid causes endocrine effects.
    2. Metabolism in plants and animals. The metabolism of imidacloprid 
in plants and animals is adequately understood for the purposes of 
these tolerances. The residues of concern in plants and animals are 
combined residues of imidacloprid and its metabolites containing the 6-
chloro-pyridinyl moiety, all calculated as imidacloprid (as stated in 
40 CFR 180.472). Adequate methods are available for the determination 
of the regulated imidacloprid residues.
    3. Analytical method. There is a practical analytical method for 
detecting and measuring levels of imidocloprid and its metabolites in 
or on food with a limit of detection that allows monitoring of food 
with residues at or above the levels set in this tolerance. The 
proposed analytical method for determining residues is Bayer method 
00200 for imidacloprid residues on plants and Bayer method 00191 for 
imidacloprid residues in animal tissues and milk. Copies of these 
methods have been forwarded to Food and Drug Administration (FDA) for 
publication in PAM Volume II. Both of these methods are common moiety 
GC-MS methods. EPA has provided information on this method to FDA. 
Because of the long lead time from establishing these tolerances to 
publication, the enforcement methodology is being made available in the 
interim to anyone interested in pesticide enforcement when requested by 
mail from: Calvin Furlow, Public Response Branch, Field Operations 
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. 1130A, 1921 
Jefferson Davis Highway, Arlington, VA, 703- 305-5937.
    4. International tolerances. There are no Mexican, Canadian, or 
Codex Alimentarius Commission (Codex) maximum residue levels and/or 
tolerances established for residues of imidacloprid on cucurbits.

II. 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 FFDCA section 408(e) and (1)(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 governs 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 June 24, 1997, file written objections to any 
aspect of this regulation (including the automatic revocation 
provision) 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 issue(s) on which a hearing is requested, the 
requestor's contentions on such issues, and a summary of any evidence 
relied upon by the objector (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 a 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 issue(s) in the manner sought by the requestor would be 
adequate to justify the action requested (40 CFR 178.32). Information 
submitted in connection with an objection or hearing request may be 
claimed confidential by marking any part or all of that information as 
``Confidential Business Information'' (CBI). Information so marked will 
not be disclosed except in accordance with procedures set forth in 40 
CFR part 2. A copy of the information that does not contain CBI must be 
submitted for inclusion in the public record. Information not marked 
confidential may be disclosed publicly by EPA without prior notice.

III. Public Record

    A record has been established for this rulemaking under document 
control number [OPP-300468; PP-5E4598]. A public version of this 
record, which does not include any information claimed as CBI, is 
available for inspection from 8:30 a.m. to 4:00 p.m., Monday through 
Friday, excluding legal holidays. The public record is located in Room 
1132 of the Public Response and Program Resources Branch, Field 
Operation Division (7506C), Office of Pesticide Programs, Environmental 
Protection Agency, Crystal Mall #2, 1921 Jefferson Davis Highway, 
Arlington, VA.
    The official record for this rulemaking, as well as the public 
version, as described above, is kept in paper form. Accordingly, in the 
event there are objections and hearing requests, 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. The official rulemaking 
record is the paper record maintained at the address in ``ADDRESSES'' 
at the beginning of this document.

IV. 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 subject to 
approval under 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 mandates'' as described in Title II of the Unfunded 
Mandates Reform Act of 1995 (Pub. L. 104-4), or require prior 
consultation as specified by Executive Order 12875 (58 FR 58093, 
October 28, l993), or special considerations as required by Executive 
Order 12898 (59 FR 7629, February 16, 1994).
    Because tolerances 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).

[[Page 20123]]

    Under 5 U.S.C. 801(a)(1)(A) of 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).

List of Subjects in 40 CFR Parts 180, 185, and 186

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

    Dated: April 16, 1997.

Stephen L. Johnson,

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 180.472 is revised to read as follows:


Sec. 180.472  Imidacloprid; tolerances for residues.

    (a) General. Tolerances are established permitting the combined 
residues of the insecticide imidacloprid (1-[6-chloro-3-pyridinyl) 
methyl]-N-nitro-2-imidazolidinimine) and its metabolites containing the 
6-chloropyridinyl moiety, all expressed as 1-[(6-chloro-3-
pyridinyl)methyl]-N-nitro-2-imidazolidinimine, in or on the following 
food commodities:

------------------------------------------------------------------------
                                                             Expiration/
                  Commodities                    Parts per    Revocation
                                                  million        date   
------------------------------------------------------------------------
                                                                        
Apples........................................          0.5         None
Apples, pomace (wet)..........................          3.0         None
Barley, forage................................          1.5     November
                                                                28, 1998
Barley, grain.................................         0.05     November
                                                                28, 1998
Barley, straw.................................          0.2     November
                                                                28, 1998
Beet roots....................................          0.3     November
                                                                29, 1997
Beet tops.....................................          3.5     November
                                                                29, 1997
Beets, sugar (roots)..........................         0.05   August 24,
                                                                    1998
Beets, sugar (tops)...........................          0.1   August 24,
                                                                    1998
Beets, sugar, molasses........................          0.3   August 24,
                                                                    1998
Brassica vegetables crop group................          3.5         None
Canola........................................         0.05         None
Cattle, fat...................................          0.3         None
Cattle, mbyp..................................          0.3         None
Cattle, meat..................................          0.3         None
Cotton, gin byproducts........................          4.0         None
Cottonseed....................................          6.0         None
Cottonseed meal...............................          8.0         None
Eggs..........................................         0.02         None
Fruiting vegetables crop group................          1.0         None
Goats, fat....................................          0.3         None
Goats, mbyp...................................          0.3         None
Goats, meat...................................          0.3         None
Grape, juice..................................          1.5         None
Grape, pomace (wet or dried)..................          5.0         None
Grape, raisin.................................          1.5         None
Grape, raisin waste...........................         15.0         None
Grapes........................................          1.0         None
Hogs, fat.....................................          0.3         None
Hogs, mbyp....................................          0.3         None
Hogs, meat....................................          0.3         None
Hops, dried...................................          6.0         None
Horses, fat...................................          0.3         None
Horses, mbyp..................................          0.3         None
Horses, meat..................................          0.3         None
Leafy greens subgroup.........................          3.5         None
Lettuce, head and leaf........................          3.5         None
Mango.........................................          0.2         None
Milk..........................................          0.1         None
Pome fruits crop group........................          0.6         None
Potato, chip..................................          0.4         None
Potato, waste.................................          0.9         None
Potatoes......................................          0.3         None
Poultry, fat..................................         0.05         None
Poultry, mbyp.................................         0.05         None
Poultry, meat.................................         0.05         None
Sheep, fat....................................          0.3         None
Sheep, mbyp...................................          0.3         None
Sheep, meat...................................          0.3         None
Sorghum, forage...............................          0.1     November
                                                                17, 1997
Sorghum, straw................................          0.1     November
                                                                17, 1997
Sorghum, grain................................         0.05     November
                                                                17, 1997
Tomato, paste.................................          6.0         None
Tomato, pomace (wet or dried).................          4.0         None
Tomato, puree.................................          3.0         None
Turnip roots..................................          0.3     November
                                                                29, 1997
Turnip tops...................................          3.5     November
                                                                29, 1997
Wheat, forage.................................          7.0   August 24,
                                                                    1998
Wheat, grain..................................         0.05   August 24,
                                                                    1998
Wheat, straw..................................          0.3   August 24,
                                                                    1998
------------------------------------------------------------------------

    (b) Section 18 emergency exemptions. [Reserved]
    (c) Tolerances with regional registrations. [Reserved]
    (d) Indirect or inadvertent residues. Tolerances are established 
for indirect or inadvertent combined residues of the insecticide 
imidacloprid (1-[(6-chloro-3-pyridinyl)methyl]-N-nitro-2-
imidazolidinimine) and its metabolites containing the 6-chloropyridinyl 
moiety, all expressed as 1-[(6-chloro-3-pyridinyl)methyl]-N-nitro-2-
imidazolidinimine, when present therein as a result of the application 
of the pesticide to growing crops listed in this section and other non-
food crops as follows:

------------------------------------------------------------------------
                                                             Expiration/
                  Commodities                    Parts per    Revocation
                                                  million        date   
------------------------------------------------------------------------
Vegetables, cucurbit..........................      0.2        December 
                                                               31, 1997 
------------------------------------------------------------------------

PART 185--[AMENDED]

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


Sec. 185.900  [Removed]

    2. Section 185.900 is removed.

PART 186--[AMENDED]

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


Sec. 186.900  [Removed]

    2. Section 186.900 is removed.
[FR Doc. 97-10725 Filed 4-24-97; 8:45 am]
BILLING CODE 6560-50-F