[Federal Register Volume 66, Number 246 (Friday, December 21, 2001)]
[Notices]
[Pages 65950-65954]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-31494]



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ENVIRONMENTAL PROTECTION AGENCY

[PF-1063; FRL-6814-1]


Notice of Filing a Pesticide Petition to Establish a Tolerance 
for a Certain Pesticide Chemical in or on Food

AGENCY: Environmental Protection Agency (EPA).

ACTION: Notice.

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SUMMARY: This notice announces the initial filing of a pesticide 
petition proposing the establishment of regulations for residues of a 
certain pesticide chemical in or on various food commodities.

DATES: Comments, identified by docket control number PF-1063, must be 
received on or before January 22, 2002.

ADDRESSES: Comments may be submitted by mail, electronically, or in 
person. Please follow the detailed instructions for each method as 
provided in Unit I.C. of the SUPPLEMENTARY INFORMATION. To ensure 
proper receipt by EPA, it is imperative that you identify docket 
control number PF-1063, in the subject line on the first page of your 
response.

FOR FURTHER INFORMATION CONTACT: By mail: Hoyt Jamerson, Registration 
Support Branch, Registration Division (7505C), Office of Pesticide 
Programs, Environmental Protection Agency, 1200 Pennsylvania Ave., NW., 
Washington, DC 20460; telephone number: (703) 308-9368; e-mail address: 
[email protected].

SUPPLEMENTARY INFORMATION:

I. General Information

A. Does this Action Apply to Me?

    You may be affected by this action if you are an agricultural 
producer, food manufacturer or pesticide manufacturer. Potentially 
affected categories and entities may include, but are not limited to:

------------------------------------------------------------------------
                                                          Examples of
           Categories                 NAICS codes         potentially
                                                       affected entities
------------------------------------------------------------------------
Industry                          111                 Crop production
                                  112                 Animal production
                                  311                 Food manufacturing
                                  32532               Pesticide
                                                       manufacturing
------------------------------------------------------------------------

    This listing is not intended to be exhaustive, but rather provides 
a guide for readers regarding entities likely to be affected by this 
action. Other types of entities not listed in the table could also be 
affected. The North American Industrial Classification System (NAICS) 
codes have been provided to assist you and others in determining 
whether or not this action might apply to certain entities. If you have 
questions regarding the applicability of this action to a particular 
entity, consult the person listed under FOR FURTHER INFORMATION 
CONTACT.

B. How Can I Get Additional Information, Including Copies of this 
Document and Other Related Documents?

    1. Electronically. You may obtain electronic copies of this 
document, and certain other related documents that might be available 
electronically, from the EPA Internet Home Page at http://www.epa.gov/. 
To access this document, on the Home Page select ``Laws and 
Regulations'' and then look up the entry for this document under the 
``Federal Register--Environmental Documents.'' You can also go directly 
to the Federal Register listings at http://www.epa.gov/fedrgstr/.
    2. In person. The Agency has established an official record for 
this action under docket control number PF-1063. The official record 
consists of the documents specifically referenced in this action, any 
public comments received during an applicable comment period, and other 
information related to this action, including any information claimed 
as confidential business information (CBI). This official record 
includes the documents that are physically located in the docket, as 
well as the documents that are referenced in those documents. The 
public version of the official record does not include any information 
claimed as CBI. The public version of the official record, which 
includes printed, paper versions of any electronic comments submitted 
during an applicable comment period, is available for inspection in the 
Public Information and Records Integrity Branch (PIRIB), Rm. 119, 
Crystal Mall #2, 1921 Jefferson Davis Highway, Arlington, VA, from 8:30 
a.m. to 4 p.m., Monday through Friday, excluding legal holidays. The 
PIRIB telephone number is (703) 305-5805.

C. How and to Whom Do I Submit Comments?

    You may submit comments through the mail, in person, or 
electronically. To ensure proper receipt by EPA, it is imperative that 
you identify docket control number PF-1063, in the subject line on the 
first page of your response.
    1. By mail. Submit your comments to: Public Information and Records 
Integrity Branch (PIRIB), Information Resources and Services Division 
(7502C), Office of Pesticide Programs (OPP), Environmental Protection 
Agency, 1200 Pennsylvania Ave., NW., Washington, DC 20460.
    2. In person or by courier. Deliver your comments to: Public 
Information and Records Integrity Branch (PIRIB), Information Resources 
and Services Division (7502C), Office of Pesticide Programs (OPP), 
Environmental Protection Agency, Rm. 119, Crystal Mall #2, 1921 
Jefferson Davis Highway, Arlington, VA. The PIRIB is open from 8:30 
a.m. to 4 p.m., Monday through Friday, excluding legal holidays. The 
PIRIB telephone number is (703) 305-5805.
    3. Electronically. You may submit your comments electronically by 
e-mail to: [email protected], or you can submit a computer disk as 
described above. Do not submit any information electronically that you 
consider to be CBI. Avoid the use of special characters and any form of 
encryption. Electronic submissions will be accepted in Wordperfect 6.1/
8.0 or ASCII file format. All comments in electronic form must be 
identified by docket control number PF-1063. Electronic comments may 
also be filed online at many Federal Depository Libraries.

D. How Should I Handle CBI That I Want to Submit to the Agency?

    Do not submit any information electronically that you consider to 
be CBI. You may claim information that you submit to EPA in response to 
this document as CBI by marking any part or all of that information as 
CBI. Information so marked will not be disclosed except in accordance 
with procedures set forth in 40 CFR part 2. In addition to one complete 
version of the comment that includes any information claimed as CBI, a 
copy of the comment that does not contain the information claimed as 
CBI must be submitted for inclusion in the public version of the 
official record. Information not marked confidential will be included 
in the public version of the official record without prior notice. If 
you have any questions about CBI or the procedures for claiming CBI, 
please consult the person identified under FOR FURTHER INFORMATION 
CONTACT.

E. What Should I Consider as I Prepare My Comments for EPA?

    You may find the following suggestions helpful for preparing your 
comments:
    1. Explain your views as clearly as possible.
    2. Describe any assumptions that you used.

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    3. Provide copies of any technical information and/or data you used 
that support your views.
    4. If you estimate potential burden or costs, explain how you 
arrived at the estimate that you provide.
    5. Provide specific examples to illustrate your concerns.
    6. Make sure to submit your comments by the deadline in this 
notice.
    7. To ensure proper receipt by EPA, be sure to identify the docket 
control number assigned to this action in the subject line on the first 
page of your response. You may also provide the name, date, and Federal 
Register citation.

II. What Action is the Agency Taking?

    EPA has received a pesticide petition as follows proposing the 
establishment and/or amendment of regulations for residues of a certain 
pesticide chemical in or on various food commodities under section 408 
of the Federal Food, Drug, and Cosmetic Act (FFDCA), 21 U.S.C. 346a. 
EPA has determined that this petition contains data or information 
regarding the elements set forth in section 408(d)(2); however, EPA has 
not fully evaluated the sufficiency of the submitted data at this time 
or whether the data support granting of the petition. Additional data 
may be needed before EPA rules on the petition.

List of Subjects

    Environmental protection, Agricultural commodities, Feed additives, 
Food additives, Pesticides and pests, Reporting and recordkeeping 
requirements.

    Dated: December 12, 2001.
Peter Caulkins,
Acting Director, Registration Division, Office of Pesticide Programs.

Summary of Petition

    The petitioner summary of the pesticide petition is printed below 
as required by section 408(d)(3) of the FFDCA. The summary of the 
petition was prepared by BASF Corporation, Agricultural Products, 
26Davis Drive, Research Triangle Park, NC 27709 and represents the view 
of BASF Corporation. EPA is publishing the petition summary verbatim 
without editing it in any way. The petition summary announces the 
availability of a description of the analytical methods available to 
EPA for the detection and measurement of the pesticide chemical 
residues or an explanation of why no such method is needed.

Interregional Research Project Number 4

PP 0E6209

    EPA has received a pesticide petition 0E6209 from the Interregional 
Research Project Number 4 (IR-4), 681 U.S. Highway #1 South, North 
Brunswick, NJ 08902-3390 proposing, pursuant to section 408(d) of the 
FFDCA, 21 U.S.C. 346a(d), to amend 40 CFR part 180 by establishing a 
tolerance for residues of (3,6-dichloro-o-anisic acid (dicamba) in or 
on the raw agricultural commodities (RAC): Corn, sweet, kernel plus cob 
with husks removed at 0.04 part per million (ppm); corn, sweet, forage 
at 0.50 ppm; and corn, sweet, stover at 0.50 ppm. EPA has determined 
that the petition contains data or information regarding the elements 
set forth in section 408(d)(2) of the FFDCA; however, EPA has not fully 
evaluated the sufficiency of the submitted data at this time or whether 
the data support granting of the petition. Additional data may be 
needed before EPA rules on the petition.

A. Residue Chemistry

    1. Plant metabolism. The metabolism is adequately understood on the 
basis of soybean, asparagus, cotton, sugarcane, and published data on 
grass. In the majority of registered crops, the major metabolite is the 
3,6-dichloro-5-OH-o-anisic acid. Tolerances are expressed as the 
dicamba parent plus the respective major metabolite.
    2. Analytical method. BASF Corp. has provided suitable 
independently validated analytical methods for detecting and measuring 
levels of dicamba, and its metabolites in or on food with a limit of 
detection that allows monitoring of food with residues at or above the 
levels described in these and the existing tolerances. Adequate methods 
are available in PAM-II for enforcement purposes. The analytical method 
involves extraction, partition, clean-up and detection of residues by 
gas chromatography/electron capture detector (gc/ecd).
    3. Magnitude of residues. Residue trials have been conducted with 
dicamba/diflufenzopyr end-use product distinct on the sweet corn crop 
for expanded use requested in the subject petition. The tolerances 
listed below are based on the maximum expected residue from 
geographically representative field trial data: Proposed tolerances for 
combined residues of the herbicide dicamba (3,6-dichloro-o-anisic acid) 
and its metabolite 3,6-dichloro-5-hydroxy-o-anisic acid in or on the 
RAC as follows (40 CFR 180.227(a)): Corn, sweet, kernel plus cob with 
husks removed at 0.04 ppm; corn, sweet, forage at 0.05 ppm; and corn, 
sweet, stover at 0.05 ppm.
    4. Animal residue. The uses proposed do not yield secondary 
residues in meat, and milk above the tolerances already published under 
40 CFR 180.227. Data from metabolism and feeding studies in poultry 
have established that the maximum expected dietary burden from crops 
treated with dicamba, will not result in quantifiable residues above 
the limits of the analytical method.

B. Toxicological Profile

    1. Acute toxicity. Oral rat LD50: 1,879 milligrams/
kilograms (mg/kg) (m) and 1,581 mg/kg (f). Acute dermal rat 
LD50: > 2,000 kg/kg (m/f). Acute inhalation rat 
LC50: > 9.6 mg/L (m/f). Primary eye irritation: Extremely 
irritating and corrosive to the eye. Primary dermal irritation rabbits: 
Not a primary skin irritant. Dermal sensitization guinea pigs: Moderate 
potential to cause dermal sensitization. Acute neurotoxicity: No 
observed adverse levels (NOAEL) < 300 mg/kg (low dose). No 
neuropathological effects were found.
    2. Genotoxicity. Ames: Negative. In vitro chromosome aberration in 
Chinese Hamster Ovary: Negative. Sex-linked recessive lethal in 
Drosophila: Negative. Aberrations in rat bone marrow: Negative. Mitotic 
recombination: Negative. UDH Unscheduled DNA synthesis (UDS) with WI-
38) human lung fibroblasts: Negative. Differential toxicity with E. 
coli pol A and B. subtillus: Positive. Differential toxicity with S. 
typhimurium: Negative. UDS in human lung lymphocytes with activation: 
Negative; slight increase of sister chromatid exchange in human 
cultured lymphocytes; positive in in vivo unwinding of liver DNA 
Inhalable Particles (in ip) injected rats.
    3. Reproductive and developmental toxicity. Rodent developmental 
toxicity rat: Oral doses of 0, 64, 160, or 400 mg/kg were administered 
daily during gestation days 6 to 19. The numbers of implantations, 
resorptions, and fetuses for test animals were similar to those numbers 
for control animals. No abnormalities were attributed to exposure to 
dicamba. Technical dicamba was not found to be teratogenic with the 
test system/study design employed. Maternal toxicity was found only at 
the highest dose tested (HDT) and the NOAEL was 160 mg/kg/day.
    i. Rabbit developmental toxicity. Dicamba was administered orally 
(undiluted) via capsule to groups of 20 artificially inseminated New 
Zealand White rabbits. Dose levels of 0, 30, 150, or, 300 mg/kg were 
administered once daily on days 6-18 of presumed-

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gestation (day 0 = day of insemination). Females were sacrificed on day 
29 of presumed gestation. There were no deaths attributed to treatment. 
At the 150 mg/kg and 300 mg/kg levels, increased numbers of does with 
decreased motor activity and statistically significant numbers of does 
with ataxia were noted. At 300 mg/kg, a significant number of does had 
rales and an increased number of does showed labored breathing, 
perinasal substance, dried feces, impaired righting reflex, and red 
substance in the cage pan. These clinical observations were considered 
to be effects of treatment. Females in the 300 mg/kg group had 
statistically significant body weight loss for the entire dosage 
period. At 150 mg/kg, females lost weight on day 7 and 8 of presumed 
gestation. Although, compensatory weight gains occurred during the 
post-treatment period (days 19-29 of gestation), body weight gains 
remained statistically significantly reduced on days 6-29 of gestation 
in the 300 mg/kg group. No significant differences were obtained in 
litter averages forcorpora lutea, implants, litter sizes, resorption 
sites, percent male fetuses, fetal body weight, percent resorbed 
conceptuses or number of does with any resorptions. No gross external, 
soft tissue or skeletal alterations in fetuses were considered to be 
related to treatment. The maternal NOAEL for technical dicamba to 
pregnant rabbits was 30 mg/kg/day. Levels of 150 and 300 mg/kg caused 
abortions, but were at significant maternally toxic doses. The 
developmental NOAEL was the highest dose tested, 300 mg/kg/day. There 
were no effects on embryo-fetal viability or development at any level.
    ii. Two-generation reproduction rat. Potential effects on growth 
and reproductive performance were assessed over 2-generations of rats 
maintained on diets containing technical dicamba at concentrations of 0 
control, 500, 1,500 or 5,000 ppm. Exposure at 5,000 ppm was associated 
with a slower growth rate of F1 pups prior to weaning and resulted in 
lower initial body weights in those selected as parental animals. The 
lower body weight was associated with a decrease in both food 
consumption and water intake. Sexual maturation was slightly delayed 
among males, but was likely associated with the initial reduced growth 
rate. Increased liver weights were noted consistently for adults of 
both generations and for weanlings. There were no effects on 
reproductive ability from treatment at any level. The low pregnancy 
rate among F, females in all groups was considered to be due to 
increased weights of those females. The NOAEL and LOAEL for system 
toxicity were 1,500 and 5,000 ppm, respectively. The NOAEL and LOAEL 
for reproductive toxicity were 500 (45 mg/kg/day) and 1,500 ppm, 
respectively.
    4. Subchronic toxicity--i. 21-Day dermal. There were no dicamba 
related changes in general behavior, appearance, body weight, or in 
blood and urine analysis. There were no compound-related gross 
pathology lesions, only skin lesions. There were no significant organ 
weight variations observed.
    ii. Thirteen-week rodent feeding (rat). Rats were offered technical 
dicamba at dietary concentrations of 0, 1,000, 5,000, or 10,000 ppm. 
The mean body weight and food consumption values for the high dietary 
level animals were decreased from the control values. No adverse 
treatment-related findings were noted in either the blood parameters 
investigated or necropsy evaluation. Microscopic examinations of the 
liver revealed an absence or reduction of cytoplasmic vacuolation in 
the hepatocytes of the high dietary level animals. The no-effect level 
was suggested to be 5,000 ppm.
    iii. Eight-week rodent (dog). Technical dicamba was offered orally 
at dietary concentrations of 0 (Control), 100, 500, or 2,500 ppm to 
dogs for 1 year. Initially, a decrease in food consumption was noted 
mainly among males at 500 and 2,500 ppm. This was most notable in a 
single 2,500 ppm male resulting in almost no food consumed for the 
first 3 weeks of feeding. Following administration of the 2,500 ppm 
diet in a water slurry during weeks 4-6, this male was placed back on 
feed and food consumption stabilized. There appears to be a limit to 
the amount of material that can be added to the feed before dogs will 
not consume the diet. The 2,500 ppm level was considered close to the 
maximum that could be employed, as 1 dog failed to consume the diet 
when offered in the usual form. Due mainly to the aforementioned male, 
mean body weight of 2,500 ppm males did not increase until week 5. The 
overall body weight gain for the 1 year period was comparable for all 
groups. It was concluded that aside from the lower food consumption, 
the no-effect level for toxicity was 50-60 mg dicamba/kg body weight 
(2,500 ppm) in both males and females. Because of the lack of toxicity 
shown in this study, the RfD Peer Review committee concurred that the 
NOEL was 2,500 ppm (HDT) and a LOEL was not established.
    Sub-chronic neurotoxicity. NOAEL was established at 401 (m) and 472 
(f) mg/kg/day. No histopathological effects on the peripheral or 
central nervous system were noted.
    5. Chronic toxicity--i.Chronic feeding/carcinogenicity in rat. 
Groups of 60 rats/sex were maintained on diets containing technical 
dicamba at concentrations of either 0, 50, 250, or 2,500 ppm. An 
interim sacrifice of 10/sex/level was conducted at 12 months. Initially 
scheduled as a 27-month study, males were sacrificed at 115 weeks and 
females at 118 weeks due to survival rates. In males, no statistically 
significant differences in data for all tumors combined, all benign 
tumors combined, and all malignant tumors combined were obtained. A 
slight increase in malignant lymphoma was not statistically significant 
(pairwise comparisons), and was not considered to be toxicologically 
significant. A slight increase in thyroid parafollicular cell carcinoma 
in the high treatment group was noted but was not statistically 
significant in pairwise comparisons. In females, no statistically 
significant differences were noted in comparisons with all tumors 
combined, all benign tumors combined, and all malignant tumors combined 
or in any individual tumor type. In summary, no signs of toxicity 
related to administration of dicamba were noted. Findings among animals 
in the three treatment groups were considered to be comparable to 
findings among the control animals. Dicamba was not carcinogenic for 
animals of the species, strain, and age under the conditions of the 
study. Based on the results of the study, the no effect level was 
considered to be 2,500 ppm.
    ii. Carcinogenicity in mice. Groups of 52 male and 52 female mice 
were fed diets containing dicamba at concentrations of 0, 50, 150, 
1,000, or 3,000 ppm. Males were sacrificed following 89 weeks of 
feeding and females were sacrificed following 104 weeks of feeding. 
Reduced body weight gain (not statistically different) was noted among 
3,000 ppm females. Increased mortality noted among 3,000 ppm males was 
considered unlikely to be related to treatment but could not be 
completely excluded. An increased incidence in lymphoid tumors, showing 
a statistical significance at 150 and 1,000 ppm, occurred in females. 
However, the incidence at 3,000 ppm did not statistically differ from 
control. Additionally, there was no significant trend with dosage and 
the values for treated females were within historical control data. 
Finally, the incidence of benign and malignant tumors in any tissue 
were similar for treated and control animals. Administration of dicamba 
in the diet at achieved intakes ranging from 5.5 to 364 mg/kg/day

[[Page 65953]]

produced no evidence of tumorigenic potential. Generally, no findings 
among mice receiving 1,000 ppm or below were considered to be of 
toxicological significance. The dietary level of 1,000 ppm (108 mg/kg/
day in males and 121 mg/kg/day in females) was defined as the no toxic 
effect level. However, the RfD committee chose to establish the NOAEL 
at 3,000 ppm and stated that no LOAEL had been established.
    iii. Chronic dog. In a 1-year chronic feeding study, dicamba 86.8% 
active ingredient (a.i.) was administered to Beagle dogs (4/sex/group) 
in the diet at 0, 10, 500 or 2,500 ppm (0, 2, 11, or 52 mg/kg/day) for 
12 months. No adverse effects were observed at any dose level. No 
abnormalities in clinical signs, hematology, clinical chemistry, or 
urinalysis were reported. No abnormal findings were made at necropsy, 
nor were there any significant changes in food consumption or body 
weight. The NOAEL for this study is 52 mg/kg/day, the highest dose 
level tested. The LOAEL could not be established.
    6. Animal metabolism. Dicamba has been tested in rats, dogs, 
cattle, goats, and hens. In all cases, dicamba is excreted very 
rapidly, mainly as unchanged dicamba and to a lesser extent as 3,6-
dichloro-2-hydroxybenzoic acid with trace amounts of 3,6-dichloro-5-
hydroxy-o-anisic acid. The results of these studies demonstrate that 
dicamba is not persistent and does not accumulate in animals.
    7. Metabolite toxicology. Toxicity of the metabolites of dicamba to 
humans is concurrently evaluated during toxicity testing because both 
plant, and animal metabolites are formed during the course of toxicity 
tests. Both plant, and animal major metabolites are considered not of 
toxicological concern.
    8. Endocrine disruption. No specific tests have been conducted with 
dicamba to determine whether the pesticide may have an effect in humans 
that is similar to an effect produced by a naturally occurring estrogen 
or other endocrine effect. However, available data have not implicated 
dicamba in such effects.

C. Aggregate Exposure

    1. Dietary exposure. EPA has established the RfD for 3,6-dichloro-
o-anisic acid (dicamba) at 0.045 mg/kg/day. This RfD is based on a 2-
generation reproduction study in rat with a NOAEL of 45 mg/kg/day and 
an uncertainty factor of 1,000.
    Cancer classification and risk assessment. The cancer 
classification of dicamba has been reviewed and recommended that the 
compound be classified as a Group D carcinogen, not classifiable as to 
human carcinogenicity.
    i. Food-chronic dietary exposure. The estimated aggregate dietary 
exposure is based on the Theoretical Maximum Residue Contribution 
(TMRC) calculation. The TMRC is a ``worst case'' estimate of dietary 
exposure since it is assumed that 100% of all crops for which 
tolerances are established are treated, and that residues are at the 
tolerances level. The dicamba TMRC for the overall U.S. population from 
the currently established and proposed tolerances represents 
approximately 23.9% of the RfD.
    ii. Drinking water. EPA does not have monitoring data available to 
perform a quantitative drinking water risk assessment for dicamba at 
this time. A Tier 1 drinking water assessment of dicamba using the 
GENEEC model and the SCI-GROW model were run to produce estimates of 
dicamba concentrations in surface and ground water respectively. 
Estimated maximum concentrations of dicamba in surface and ground water 
are 98 and 0.013 ppb, respectively. The estimated concentrations of 
dicamba in surface and ground water are less than EPA's level of 
comparison for dicamba in drinking water as a contribution to chronic 
aggregate exposure. Therefore, taking into account present uses, and 
uses proposed in this action, BASF Corporation concludes with 
reasonable certainty that residues of dicamba in drinking water (when 
considered along with other sources of exposure for which there are 
reliable data), would not result in unacceptable levels of aggregate 
human health risk at this time.
    iii. Acute exposure and risk. This acute dietary (food) risk 
assessment used the Dietary Exposure Evaluation Model (DEEM). 
Regulating at the 95th percentile, acute dietary exposure used up only 
28.6% of the acute RfD. The risks from acute dietary exposures to 
dicamba do not exceed EPA's level of concern.
    iv. Chronic exposure and risk. The chronic dietary exposure 
analysis from food sources was conducted using the RfD of 0.045 mg/kg/
day. In conducting this chronic dietary risk assessment, EPA has made 
very conservative assumptions: 100% of RACs having dicamba tolerances 
will contain dicamba residues and those residues will be at the level 
of the established tolerance. This results in an overestimate of human 
dietary exposure. The chronic DEEM analysis used mean consumption (3-
day average) data, and showed U.S. population (48 states) at only 23.9% 
of the RfD.
    2. Non-dietary exposure. Dicamba (3,6-dichloro-o-anisic acid), is 
currently registered for use on outdoor residential and recreational 
turf. Application is made by both homeowners and professional 
applicators. There is a potential oral, inhalation, eye and dermal 
exposure to infants and children to dicamba from the registered uses 
for lawn and turfgrass weed control. These exposures are considered to 
be very low. Currently there are no inhalation or eye exposure data 
required for post-application of pesticides to lawns and turf. As 
inhalation exposure for mixer/loaders is acceptable, the risk to 
infants and children from inhalation exposure under a much lower 
exposure scenario is characterized qualitatively as being extremely 
low. Exposure data are required for hand to mouth movements of infants 
and children. As there are no chemical-specific or site-specific data 
available to determine the potential risks associated with residential 
exposures, the EPA has determined that residential exposure and risk 
are acceptable for dosages of 0.5 lb/A, based on a dermal NOAEL of 
1,000 mg/kg/day and exposures of 0.051 mg/kg/day for low pressure hand 
wand, liquid formulations, and 0.079 mg/kg/day for granular 
formulations. For residential post-application exposure and risk 
assessment, EPA determined that the potential residential post-
application risks for short-term and intermediate exposures did not 
exceed their level of concern. In this analysis both oral and dermal 
exposures, and risks for adults and infants from post-applications were 
determined. This analysis was based on assumptions and generic data 
from the Draft HED Standard Operating Procedures (SOPs) for Residential 
Exposure Assessments (December 18, l997). These SOPs rely on what are 
considered to be upper-percentile assumptions and intended to represent 
Tier 1 assessments.

D. Cumulative Effects

    At this time, there is no available data to determine whether 
dicamba, and its metabolites 3,6-dichloro-5-hydroxy-o-anisic acid and 
3,6-dichloro-o-2-hydroxybenzoic acid, have a common mechanism of 
toxicity with other substances or how to include this pesticide or its 
metabolites in a cumulative risk assessment. For the purposes of this 
tolerance action, therefore, BASF Corporation has not assumed that 
dicamba and its metabolites have a common mechanism of toxicity with 
other substances.

E. Safety Determination

    1. U.S. population. Using the conservative exposure assumptions 
described above and based on the

[[Page 65954]]

completeness and the reliability of the toxicity data, a risk 
assessment for chronic dietary exposure from food and feed uses was 
made for all sub-populations. The percentage of the RfD occupied is 
only approximately 23.9% for the general population and 71.1% for non-
nursing infants the most exposed group.
    2. Infants and children. There was evidence of increased 
susceptibility to the offspring following prenatal and/or postnatal 
exposure in the 2-generation reproduction study in rat. In this study, 
offspring toxicity was manifested as significantly decreased pup growth 
in all generations and mating at a dose lower than that which caused 
parental systemic toxicity (abortions and clinical signs of 
neurotoxicity). Available studies indicated no increase susceptibility 
of rats or rabbits in in utero exposure to dicamba. In a prenatal 
developmental toxicity study in rats, there was no evidence of 
developmental toxicity at the highest dose tested. In a prenatal 
developmental toxicity study in rabbits, developmental toxicity 
(irregular ossification of internasal bones), were only seen at the 
dose that caused maternal toxicity (abortions and neurotoxic clinical 
signs). Therefore, there is an adequate toxicity data base for dicamba 
and exposure data are complete or are estimated based on data that 
reasonably account for potential exposures. A ten-fold safety factor 
for increased susceptibility of infants and children was applied for 
chronic (long-term) exposure, and a three-fold safety factor was 
applied for acute (short- and intermediate-term) exposures to dicamba, 
due to evidence of increased susceptibility to the offspring following 
prenatal and/or postnatal exposure in the 2-generation reproduction 
study in rats. The uncertainty factor (FQPA Safety Factor) of ten-fold 
was reduced for acute dietary and short-term and intermediate-term 
residential exposures because the increased susceptibility was only 
observed in the reproduction study and not in the prenatal 
developmental studies. The FQPA Safety Factor was reduced to 3x for 
acute dietary risk assessment for all populations, including infants 
and children, because: (1) The endpoint of concern is clinical signs of 
neurotoxicity (in the absence of neuropathology) observed following a 
single oral exposure in an acute neurotoxicity study; (2) the increased 
susceptibility was seen in the offspring of parental animals receiving 
repeated oral exposures in a 2-generation reproduction toxicity study; 
and (3) no increased susceptibility was observed following in utero 
exposures of rats or rabbits in the developmental studies.

F. International Tolerances

    No CODEX maximum residue levels have been established for dicamba.

[FR Doc. 01-31494 Filed 12-20-01; 8:45 am]
BILLING CODE 6560-50-S