[Federal Register Volume 62, Number 53 (Wednesday, March 19, 1997)]
[Rules and Regulations]
[Pages 12953-12959]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-6654]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 180

[OPP-300460; FRL-5594-2]
RIN 2070-AB78


Imidacloprid; Pesticide Tolerances for Emergency Exemptions

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: This regulation establishes a time-limited tolerance for 
combined residues of the pesticide imidacloprid in or on the raw 
agricultural commodity crop group, cucurbits (Crop Group 9 cucumbers, 
melons, and squash) in connection with EPA's granting of emergency 
exemptions under section 18 of the Federal Insecticide, Fungicide, and 
Rodenticide Act authorizing use of imidacloprid on cucurbits in Texas 
and California. This regulation establishes maximum permissible levels 
for residues of imidacloprid in these foods. This tolerance will expire 
on March 31, 1998.
DATES: This regulation becomes effective March 19, 1997. The entry in 
the table expires on March 31, 1998. Objections and requests for 
hearings must be received by EPA on or before May 19, 1997.

ADDRESSES: Written objections and hearing requests, identified by the 
docket control number, [OPP-300460], 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-300460], must also be 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 
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: [email protected]. Such 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-300460]. 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: Andrea Beard, Registration 
Division (7505W), Office of Pesticide Programs, Environmental 
Protection Agency, 401 M St., SW., Washington, DC 20460. Office 
location, telephone number, and e-mail: Sixth Floor, Crystal Station 
#1, 2800 Jefferson Davis Highway, Arlington, VA 22202. (703) 308-8791, 
e-mail: [email protected].
SUPPLEMENTARY INFORMATION: EPA, pursuant to section 408(e) and (l)(6) 
of the Federal Food, Drug, and Cosmetic Act (FFDCA), 21 U.S.C. 346a(e) 
and (l)(6), is establishing tolerances for residues of the pesticide 
imidacloprid (1-[(6-chloro-3-pyridinyl)methyl]-N-nitro-2-
imidazolidinimine), in or on cucurbits, at 0.2 part per million (ppm). 
This tolerance will expire and be revoked automatically without further 
action by EPA on March 31, 1998.

[[Page 12954]]

I. Background and Statutory Authority

    The Food Quality Protection Act of 1996 (FQPA) (Pub. L. 104-170) 
was signed into law August 3, 1996. FQPA amends both the Federal Food, 
Drug, and Cosmetic Act (FFDCA), 21 U.S.C. 301 et seq., and the FIFRA, 7 
U.S.C. 136 et seq. The FQPA amendments went into effect immediately. 
Among other things, FQPA amends FFDCA to bring all EPA pesticide 
tolerance-setting activities under a new section 408 with a new safety 
standard and new procedures. These activities are described below and 
discussed in greater detail in the final rule establishing the time-
limited tolerance associated with the emergency exemption for use of 
propiconazole on sorghum (61 CFR 58135, November 13, 1996)(FRL-5572-9).
    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 drinking water, 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....''
    Section 18 of FIFRA authorizes EPA to exempt any Federal or State 
agency from any provision of FIFRA, if EPA determines that ``emergency 
conditions exist which require such exemption.'' This provision was not 
amended by FQPA. EPA has established regulations governing such 
emergency exemptions in 40 CFR part 166.
    Section 408(l)(6) requires EPA to establish a time-limited 
tolerance or exemption from the requirement for a tolerance for 
pesticide chemical residues in food that will result from the use of a 
pesticide under an emergency exemption granted by EPA under section 18 
of FIFRA. Section 408(l)(6) also requires EPA to promulgate regulations 
by August 3, 1997, governing the establishment of tolerances and 
exemptions under section 408(l)(6) and requires that the regulations be 
consistent with section 408(b)(2) and (c)(2) and FIFRA section 18.
    Section 408(l)(6) allows EPA to establish tolerances or exemptions 
from the requirement for a tolerance, in connection with EPA's granting 
of FIFRA section 18 emergency exemptions, without providing notice or a 
period for public comment. Thus, consistent with the need to act 
expeditiously on requests for emergency exemptions under FIFRA, EPA can 
establish such tolerances or exemptions under the authority of section 
408(e) and (l)(6) without notice and comment rulemaking.
    In establishing section 18-related tolerances and exemptions during 
this interim period before EPA issues the section 408(l)(6) procedural 
regulation and before EPA makes its broad policy decisions concerning 
the interpretation and implementation of the new section 408, EPA does 
not intend to set precedents for the application of section 408 and the 
new safety standard to other tolerances and exemptions. Rather, these 
early section 18 tolerance and exemption decisions will be made on a 
case-by-case basis and will not bind EPA as it proceeds with further 
rulemaking and policy development. EPA intends to act on section 18-
related tolerances and exemptions that clearly qualify under the new 
law.

II. Emergency Exemption for Imidacloprid on Cucurbits and FFDCA 
Tolerances

    The Texas Department of Agriculture and the California Department 
of Pesticide Regulation availed themselves of the authority to declare 
the existence of a crisis situation within their states, on January 27, 
and February 5, 1997, respectively, thereby authorizing use under FIFRA 
section 18 of imidacloprid on cucurbits to control white flies. The 
States of Texas and California have also requested specific exemptions 
for this use of imidacloprid. Texas and California stated that an 
emergency situation was present due to this recently introduced pest, 
its devastating effects on the cucurbit crop, and its resistance to 
registered alternatives. Texas and California state that this pest can 
have devastating effects on growers' production and revenue. After 
having reviewed their submission, EPA concurs that an emergency 
condition exists.
    As part of its assessment of these crisis declarations, EPA 
assessed the potential risks presented by residues of imidacloprid in 
or on cucurbits. In doing so, EPA considered the new safety standard in 
FFDCA section 408(b)(2), and EPA decided to grant the section 18 
exemptions only after concluding that the necessary tolerance under 
FFDCA section 408(l)(6) would clearly be consistent with the new safety 
standard and with FIFRA section 18. This tolerance for imidacloprid 
will permit the marketing of cucurbits treated in accordance with the 
provisions of the section 18 emergency exemptions. Consistent with the 
need to move quickly on the emergency exemptions and to ensure that the 
resulting food is safe and lawful, EPA is issuing this tolerance 
without notice and opportunity for public comment under section 408(e) 
as provided for in section 408(l)(6). Although this tolerance will 
expire and be revoked automatically without further action by EPA on 
March 31, 1998, under FFDCA section 408(l)(5), residues of imidacloprid 
not in excess of the amount specified in the tolerance remaining in or 
on cucurbits after that date will not be unlawful, provided the 
pesticide is applied during the term of, and in accordance with all the 
conditions of, the emergency exemptions. EPA will take action to revoke 
this tolerance earlier if any experience with, scientific data on, or 
other relevant information on this pesticide indicate that the residues 
are not safe.
    EPA has not made any decisions about whether imidacloprid meets the 
requirements for registration under FIFRA section 3 for use on 
cucurbits, or whether a permanent tolerance for imidacloprid for 
cucurbits would be appropriate. This action by EPA does not serve as a 
basis for registration of imidacloprid by a State for special local 
needs under FIFRA section 24(c). Nor does this action serve as the 
basis for any State other than Texas and California to use this product 
on this crop under section 18 of FIFRA without following all provisions 
of section 18 as identified in 40 CFR part 166. For additional 
information regarding the emergency exemptions for imidacloprid, 
contact the Agency's Registration Division at the address provided 
above.

III. Risk Assessment and Statutory Findings

    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

[[Page 12955]]

causes adverse effects (threshold effects) and doses causing no 
observed effects (the ``no-observed effect level'' or ``NOEL'').
    Once a study has been evaluated and the observed effects have been 
determined to be threshold effects, EPA generally divides the NOEL from 
the study with the lowest NOEL by an uncertainty factor (usually 100 or 
more) to determine the Reference Dose (RfD). The RfD is a level at or 
below which daily aggregate exposure over a lifetime will not pose 
appreciable risks to human health. An uncertainty factor (sometimes 
called a ``safety factor'') of 100 is commonly used since it is assumed 
that people may be up to 10 times more sensitive to pesticides than the 
test animals, and that one person or subgroup of the population (such 
as infants and children) could be up to 10 times more sensitive to a 
pesticide than another. In addition, EPA assesses the potential risks 
to infants and children based on the weight of the evidence of the 
toxicology studies and determines whether an additional uncertainty 
factor is warranted. Thus, an aggregate daily exposure to a pesticide 
residue at or below the RfD (expressed as 100 percent or less of the 
RfD) is generally considered by EPA to pose 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 
relationships. 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. 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 (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.

IV. Aggregate Risk Assessments, Cumulative Risk Discussion, and 
Determination of Safety

    Consistent with section 408(b)(2)(D), EPA has reviewed the 
available scientific data and other relevant information in support of 
this action. Imidacloprid is registered by EPA for use on turf, as a 
termiticide, and for flea control on pets. At this time EPA is not in 
possession of a registration application for imidacloprid on cucurbits. 
However, based on information submitted to the Agency, EPA has 
sufficient data to assess the hazards of imidacloprid and to make a 
determination on aggregate exposure, consistent with section 408(b)(2), 
for the time-limited tolerance for residues of imidacloprid on 
cucurbits at 0.2 ppm. EPA's assessment of the dietary exposures and 
risks associated with establishing this tolerance follows.

A. Toxicological Profile

    1. Chronic toxicity. Based on the available chronic toxicity data, 
the EPA's Office of Pesticide Programs (OPP) has established the RfD 
for imidacloprid at 0.057 milligrams/kilogram/day (mg/kg/day). The RfD 
for imidacloprid is based on a 2-year feeding study in rats with a NOEL 
of 5.7 mg/kg/day and an uncertainty factor of 100. An increase in 
thyroid lesions in males was observed at the Lowest Effect Level (LEL) 
at 16.9 mg/kg/day.
    2. Acute toxicity. Based on the available acute toxicity data, OPP 
has determined that the NOEL of 24 mg/kg/day from the developmental 
toxicity study in rabbits should be used to assess risk from acute 
toxicity. Maternal effects observed at the 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. The population subgroup of concern for this 
risk assessment is females 13+ years and older. This subgroup takes 
into account both maternal and fetal effects.
    3. Short- and intermediate-term toxicity. OPP has determined that 
available data do not demonstrate that imidacloprid has dermal or 
inhalation toxicity potential. Therefore, short-term or intermediate-
term dermal and inhalation risk assessments, for occupational and 
residential exposure scenarios, are not required.
    4. Carcinogenicity. Using its Guidelines for Carcinogen Risk 
Assessment published September 24, 1986 (51 FR 33992), EPA has 
classified imidacloprid as a ``Group E'' chemical (no evidence of 
carcinogenicity for humans) based on the results of carcinogenicity 
studies in two species. The doses tested are adequate for identifying a 
cancer risk. Thus, a cancer risk assessment would not be appropriate.

B. Aggregate Exposure

    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 raw agricultural 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. There 
are no livestock feed items associated with these section 18 requests, 
so no additional livestock dietary burden will result from this section 
18 registration. Therefore, existing meat/milk/poultry tolerances are 
adequate.
    In conducting this exposure assessment, EPA has made very 
conservative assumptions -- 100% of cucurbits and all other commodities 
having imidacloprid tolerances will contain imidacloprid tolerance 
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.
    1. Chronic exposure. Given the emergency nature of this request for 
the use of imidacloprid and the resulting need for a timely analysis 
and risk assessment, EPA has utilized the TMRC to estimate chronic 
dietary exposure

[[Page 12956]]

from the tolerances for imidacloprid on cucurbits at 0.2 ppm. The TMRC 
is obtained by multiplying the tolerance level residue for cucurbits by 
the average consumption data, which estimate the amount of cucurbits 
eaten by various population subgroups. This calculation is performed as 
well for every food having existing imidacloprid tolerances. The risk 
assessment is therefore considered to be overestimated. The Agency has 
extensive experience refining chronic dietary risk assessments for a 
broad range of pesticide chemicals. It is OPP's experience that when 
the chronic dietary risk assessment is refined using anticipated 
residue contribution (ARC) estimates derived from anticipated residue 
levels and percent crop treated data, the percent of the RfD occupied 
by the ARC is generally in the range of an order of magnitude lower 
than the percent of the RfD occupied by the unrefined TMRC. A similar 
decrease in estimated exposure to imidacloprid is expected once more 
refined data is received based on ARCs for imidacloprid on some crops.
    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).
    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 Groundwater Database'' (EPA 734-12-92-001, September 
1992) has no information concerning imidacloprid.
    Because the Agency lacks sufficient water-related exposure data to 
complete a comprehensive drinking water risk assessment for many 
pesticides, EPA has commenced and nearly completed a process to 
identify a reasonable yet conservative bounding figure for the 
potential contribution of water-related exposure to the aggregate risk 
posed by a pesticide. In developing the bounding figure, EPA estimated 
residue levels in water for a number of specific pesticides using 
various data sources. The Agency then applied the estimated residue 
levels, in conjunction with appropriate toxicological endpoints (RfD's 
or acute dietary NOEL's) and assumptions about body weight and 
consumption, to calculate, for each pesticide, the increment of 
aggregate risk contributed by consumption of contaminated water. While 
EPA has not yet pinpointed the appropriate bounding figure for 
consumption of contaminated water, the ranges the Agency is continuing 
to examine are all 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.
    2. Acute exposure. EPA has not estimated non-occupational exposures 
other than dietary for imidacloprid. Acceptable, reliable data are not 
currently available with which to assess acute risk. Imidacloprid is 
registered for turf pest control. While dietary and residential 
scenarios could possibly occur in a single day, imidacloprid would 
rarely be present on both the food eaten and the lawn on that single 
day. Even assuming this were the case, it is yet more unlikely that 
residues would be present at tolerance level on all food eaten that day 
for which imidacloprid tolerances exist, as is assumed in the acute 
dietary risk analysis, and on the lawn that same day. Because the acute 
dietary exposure estimate assumes tolerance level residues and 100% 
crop treated for all crops evaluated, it is a large over-estimate of 
exposure and it is considered to be protective of any acute exposure 
scenario.

C. Cumulative Exposure to Substances with Common Mechanism of Toxicity

    Section 408(b)(2)(D)(v) requires that, when considering whether to 
establish, modify, or revoke a tolerance, the Agency consider 
``available information'' concerning the cumulative effects of a 
particular pesticide's residues and ``other substances that have a 
common mechanism of toxicity.'' The Agency believes that ``available 
information'' in this context might include not only toxicity, 
chemistry, and exposure data, but also scientific policies and 
methodologies for understanding common mechanisms of toxicity and 
conducting cumulative risk assessments. For most pesticides, although 
the Agency has some information in its files that may turn out to be 
helpful in eventually determining whether a pesticide shares a common 
mechanism of toxicity with any other substances, EPA does not at this 
time have the methodologies to resolve the complex scientific issues 
concerning common mechanism of toxicity in a meaningful way. EPA has 
begun a pilot process to study this issue further through the 
examination of particular classes of pesticides. The Agency hopes that 
the results of this pilot process will increase the Agency's scientific 
understanding of this question such that EPA will be able to develop 
and apply scientific principles for better determining which chemicals 
have a common mechanism of toxicity and evaluating the cumulative 
effects of such chemicals. The Agency anticipates, however, that even 
as its understanding of the science of common mechanisms increases, 
decisions on specific classes of chemicals will be heavily dependent on 
chemical-specific data, much of which may not be presently available.
    Although at present the Agency does not know how to apply the 
information in its files concerning common mechanism issues to most 
risk assessments, there are pesticides as to which the common mechanism 
issues can be resolved. These pesticides include pesticides that are 
toxicologically dissimilar to existing chemical substances (in which 
case the Agency can conclude that it is unlikely that a pesticide 
shares a common mechanism of activity with other substances) and 
pesticides that produce a common toxic metabolite (in which case common 
mechanism of activity will be assumed).
    EPA does not have, at this time, available data to determine 
whether imidacloprid has a common mechanism of toxicity with other 
substances or how to include this pesticide in a cumulative risk 
assessment. Unlike other pesticides for which EPA has followed a 
cumulative risk approach based on a common mechanism of toxicity, 
imidacloprid does not appear to produce a toxic metabolite produced by 
other substances. For the purposes of this tolerance action, therefore, 
EPA has not assumed that imidacloprid has a common mechanism of 
toxicity with other substances.

D. Determination of Safety for U.S. Population

    1. Chronic risk. Using the conservative exposure assumptions 
described above, and taking into account the completeness and 
reliability of the toxicity data, EPA has concluded

[[Page 12957]]

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 percent 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 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 Margin of Exposure (MOE) value is 480. This MOE does not 
exceed the Agency's level of concern for acute dietary exposure.

E. 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 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 one or 
both parents. Reproduction studies provide information relating to 
effects from exposure to the pesticide on the reproductive capability 
of mating animals and data on systemic toxicity.
    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 the 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 rat reproduction study, the maternal (systemic) NOEL was 55 
mg/kg/day (the highest dose tested). The reproductive/developmental 
NOEL (effect on the pup) was 8 mg/kg/day, based on decreased pup body 
weight during lactation in both generations at the LOEL of 19 mg/kg/
day.
    In the 2-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 infants and children subgroup (children 1 to 6 
years old) occupies 31.0% 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 percent for nursing infants, up to 32 percent for 
children 1 to 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. 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 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.
    FFDCA section 408 provides that EPA shall apply an additional 
tenfold margin of exposure (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.
    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

[[Page 12958]]

dietary MOE would be greater than the current MOE. This provides an 
adequate safety factor for children during the prenatal and postnatal 
development.
    It is unlikely that the dietary risk will exceed 100 percent of the 
RfD or that the acute MOE would be greater 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.

V. Other Considerations

    The metabolism of imidacloprid in plants and animals is adequately 
understood for the purposes of these tolerances. There are no Mexican, 
Canadian, or Codex maximum residue levels established for residues of 
imidacloprid on cucurbits. There is a practical analytical method for 
detecting and measuring levels of imidacloprid in or on food with a 
limit of detection that allows monitoring of food with residues at or 
above the levels set in these tolerances. EPA has provided information 
on this method to FDA. The method is available to anyone who is 
interested in pesticide residue enforcement from: By mail, Calvin 
Furlow, Public Response and Program Resources 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 1128, 1921 Jefferson Davis 
Hwy., Arlington, VA 22202, 703-305-5805.

VI. Conclusion

    Therefore, a tolerance in connection with the FIFRA section 18 
emergency exemptions is established for residues of imidacloprid in/on 
cucurbits at 0.2 ppm. This tolerance will expire on March 31, 1998.

VII. Objections and Hearing Requests

    The new FFDCA section 408(g) provides essentially the same process 
for persons to ``object'' to a tolerance regulation issued by EPA under 
new section 408(e) and (l)(6) as was provided in the old section 408 
and in section 409. However, the period for filing objections is 60 
days, rather than 30 days. EPA currently has procedural regulations 
which govern the submission of objections and hearing requests. These 
regulations will require some modification to reflect the new law. 
However, until those modifications can be made, EPA will continue to 
use those procedural regulations with appropriate adjustments to 
reflect the new law.
    Any person may, by May 19, 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 issues on which a hearing is requested, the 
requestor's contentions on such issues, and a summary of any evidence 
relied upon by the requestor (40 CFR 178.27). A request for a hearing 
will be granted if the Administrator determines that the material 
submitted shows the following: There is genuine and substantial issue 
of fact; there is a reasonable possibility that available evidence 
identified by the requestor would, if established, resolve one or more 
of such issues in favor of the requestor, taking into account 
uncontested claims or facts to the contrary; and resolution of the 
factual issues in the manner sought by the requestor would be adequate 
to justify the action requested (40 CFR 178.32). Information submitted 
in connection with an objection or hearing request may be claimed 
confidential by marking any part or all of that information as 
Confidential Business Information (CBI). Information so marked will not 
be disclosed except in accordance with procedures set forth in 40 CFR 
part 2. A copy of the information that does not contain CBI must be 
submitted for inclusion in the public record. Information not marked 
confidential may be disclosed publicly by EPA without prior notice.

VIII. Public Docket

    A record has been established for this rulemaking under docket 
number [OPP-300460]. 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 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 Operations Division 
(7506C), Office of Pesticide Programs, Environmental Protection Agency, 
Crystal Mall #2, 1921 Jefferson Davis Highway, Arlington, VA.
    Electronic comments may be sent directly to EPA at:
    [email protected].

    Electronic comments must be submitted as an ASCII file avoiding the 
use of special characters and any form of encryption.
    The official record for this rulemaking, as well as the public 
version, as described above, 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 Virginia address in 
``ADDRESSES'' at the beginning of this document.

IX. 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. 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, 1993), entitled 
Enhancing the Intergovernmental Partnership, or special consideration 
as required by Executive Order 12898 (59 FR 7629, February 16, 1994).
    Because FFDCA section 408(l)(6) permits establishment of this 
regulation without a notice of proposed rulemaking, the regulatory 
flexibility analysis requirements of the Regulatory Flexibility Act, 5 
U.S.C. 604(a), do not apply.
    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.

[[Page 12959]]

List of Subjects in 40 CFR Part 180

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

    Dated: February 28, 1997.

Peter Caulkins,

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

PART 180--[AMENDED]

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

    2. In Sec. 180.472, in paragraph (d), by adding alphabetically the 
following entry to the table:


Sec. 180.472  Imidacloprid; tolerances for residues.

*      *      *      *      *      

------------------------------------------------------------------------
                                           Parts per      Expiration/   
                Commodity                   million     Revocation Date 
------------------------------------------------------------------------
                                                                        
                          *    *    *    *    *                         
Vegetables, Cucurbits...................          0.2     March 31, 1998
------------------------------------------------------------------------

*      *      *      *      *      
[FR Doc. 97-6654 Filed 3-18-97; 8:45 am]
BILLING CODE 6560-50-F