[Federal Register Volume 65, Number 164 (Wednesday, August 23, 2000)]
[Notices]
[Pages 51314-51319]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-20997]


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ENVIRONMENTAL PROTECTION AGENCY

[PF-963; FRL-6738-9]


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-963, must be 
received on or before September 22, 2000.

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-963 in the subject line on the first page of your 
response.

FOR FURTHER INFORMATION CONTACT:  By mail: Shaja R. Brothers, 
Registration Support Branch, Registration Division (7505W), Office of 
Pesticide Programs, Environmental Protection Agency, 1200 Pennsylvania 
Ave., NW., Washington, DC 20460; telephone number: (703) 308-3194; 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

[[Page 51315]]

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,'' ``Regulations and Proposed Rules,'' 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-963. 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-963 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-963. 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.
    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: August 10, 2000.
James Jones,
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 the petitioner and represents the view of the 
petitioner. 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.

[[Page 51316]]

Interregional Research Project Number 4

PP 0E6085

    EPA has received a pesticide petition (PP 0E6085) from the 
Interregional Research Project Number 4, 681 US 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 halosulfuron-methyl in or on the raw 
agricultural commodity (RAC) cucumber/squash subgroup at 0.5 parts per 
million (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. This notice includes a summary of the petition prepared by 
Monsanto Company, St. Louis, MO 63167.

A. Residue Chemistry

    1. Plant metabolism. The metabolism of halosulfuron-methyl as well 
as the nature of the residues in plants is adequately understood for 
purposes of this tolerance.
    2. Analytical method. A practical analytical method, gas 
chromatography with a nitrogen specific detector which detects and 
measures residues of halosulfuron-methyl is available for enforcement 
purposes with a limit of detection that allows monitoring of food with 
residues at or above the levels set in these tolerances. This 
enforcement method has been submitted to the Food and Drug 
Administration for publication in the Pesticide Analytical Manual (PAM 
II).
    3. Magnitude of residues. In cucumber and squash residue studies, 
there were no quantifiable residues found in the raw agricultural 
commodities using an analytical method with limit of quantitation (LOQ) 
of 0.1 ppm and 0.5 ppm, respectively.

B. Toxicological Profile

    1. Acute toxicity. Acute toxicological studies placed the 
technical-grade halosulfuron-methyl in Toxicity Category III. A 90-day 
feeding study in rats resulted in a lowest observed adverse effect 
level (LOAEL) of 497 milligrams/kilograms/day (mg/kg/day) in males and 
640 mg/kg/day in females, and a no observed adverse effect level 
(NOAEL) of 116 mg/kg/day in males and 147 mg/kg/day in females.
    2. Genotoxicity. Bacterial/mammalian microsomal mutagenicity assays 
were performed and found not to be mutagenic. Two mutagenicity studies 
were performed to test gene mutation and found to produce no 
chromosomal aberrations or gene mutations in cultured Chinese hamster 
ovary cells. An in vivo mouse micronucleus assay did not cause a 
significant increase in the frequency of micronucleated polychromatic 
erythrocytes in bone marrow cells. A mutagenicity study was performed 
on rats and found not to induce unscheduled DNA synthesis in primary 
rat hepatocytes.
    3. Reproductive and developmental toxicity. A developmental 
toxicity study in rats resulted in a developmental LOAEL of 750 mg/kg/
day, based on decreases in mean litter size and fetal body weight, and 
increases in resorptions, resorptions/dam, post-implantation loss and 
in fetal and litter incidences of soft tissue and skeletal variations, 
and a developmental NOAEL of 250 mg/kg/day. Maternal LOAEL was 750 mg/
kg/day based on increased incidence of clinical observations, reduced 
body weight gains, and reduced food consumption and food efficiency. 
The maternal NOAEL was 250 mg/kg/day.
    A developmental toxicity study in rabbits resulted in a 
developmental LOAEL of 150 mg/kg/day, based on decreased mean litter 
size and increases in resorptions, resorptions/dam and post-
implantation loss, and a developmental NOAEL of 50 mg/kg/day. The 
maternal LOAEL was 150 mg/kg/day based on reduced body weight gain and 
reduced food consumption and food efficiency. The maternal NOAEL was 50 
mg/kg/day.
    A dietary 2-generation reproduction study in rats resulted in 
parental toxicity at 223.2 mg/kg/day in males and 261.4 mg/kg/day in 
females in the form of decreased body weights, decreased body weight 
gains, and reduced food consumption during the premating period. Very 
slight effects were noted in body weight of the offspring at this dose. 
This effect was considered to be developmental toxicity (developmental 
delay) rather than a reproductive effect. No effects were noted on 
reproductive or other developmental toxicity parameters. The systemic/
developmental toxicity LOAEL was 223.2 mg/kg/day in males and 261.4 mg/
kg/day in females; the systemic/developmental toxicity NOAEL was 50.4 
mg/kg/day in males and 58.7 mg/kg/day in females. The reproductive 
LOAEL was greater than 223.2 mg/kg/day in males and 261.4 mg/kg/day in 
females; the reproductive NOAEL was equal to or greater than 223.2 mg/
kg/day in males and 261.4 mg/kg/day in females.
    4. Subchronic toxicity. A 21-day dermal toxicity study in rats 
resulted in a NOAEL of 100 mg/kg/day in males and greater than 1,000 
mg/kg/day in females. The only treatment-related effect was a decrease 
in body weight gain of the 1,000 mg/kg/day group in males.
    5. Chronic toxicity. A 1-year chronic oral study in dogs resulted 
in a LOAEL of 40 mg/kg/day based on decreased weight gain and a NOAEL 
of 10 mg/kg/day for systemic toxicity. A 78-week carcinogenicity study 
was performed on mice. Males in the 971.6 mg/kg/day group had decreased 
body weight gains and an increased incidence of microconcretion/
mineralization in the testis and epididymis. No treatment-related 
effects were noted in females. Based on these results, a LOAEL of 971.9 
mg/kg/day was established in males and NOAELs of 410 mg/kg/day in males 
and 1,214.6 mg/kg/day in females were established. The study showed no 
evidence of carcinogenicity. A combined chronic toxicity/
carcinogenicity study in rats resulted in a LOAEL of 225.2 mg/kg/day in 
males and 138.6 mg/kg/day in females based on decreased body weight 
gains, and a NOAEL of 108.3 mg/kg/day in males and 56.3 mg/kg/day in 
females. The study showed no evidence of carcinogenicity.
    6. Animal metabolism. EPA stated that the nature of the residue in 
ruminants was determined to be adequately understood. In the tissues 
and milk of goats, the major extractable residue was the unmetabolized 
parent compound. Based on the low residues of the parent compound in 
corn grain and the low transfer of residues in the metabolism study, 
tolerances on poultry products were not required. In the rat metabolism 
study, parent compound was absorbed rapidly but incompletely. Excretion 
was relatively rapid at all doses tested with majority of radioactivity 
eliminated in the urine and feces by 72 hours. Fecal elimination of 
parent was apparently the result of unabsorbed parent.
    7. Metabolite toxicology. The toxicology studies listed below were 
conducted with the 3-CSA metabolite. Based on the toxicological data of 
the 3-CSA metabolite, EPA concluded that it has lower toxicity compared 
to the parent compound and that it should not be included in the 
tolerance expression. The residue of concern is the parent compound 
only.
    i. A 90-day rat feeding study resulted in a LOAEL in males of 
>20,000 ppm

[[Page 51317]]

and a NOAEL of 20,000 ppm (1,400 mg/kg/day). In females, the LOAEL is 
10,000 ppm (772.8 mg/kg/day) based on decreased body weight gains and a 
NOAEL of 1,000 ppm (75.8 mg/kg/day).
    ii. A developmental toxicity resulted in a LOAEL for maternal 
toxicity of >1,000 mg/kg/day based on the absence of systemic toxicity, 
a NOAEL of 1,000 mg/kg/day. The developmental LOAEL is >1,000 mg/kg/day 
and the NOAEL is 1,000 mg/kg/day.
    iii. The microbial reverse gene mutation did not produce any 
mutagenic effect while the mammalian cell gene mutation/Chinese hamster 
ovary cells did not show a clear evidence of mutagenic effect in the 
Chinese hamster ovary cells.
    iv. The mouse micronucleus assay did not show any clastogenic or 
aneugenic effect.
    8. Endocrine disruption. No specific tests have been conducted with 
halosulfuron-methyl to determine whether the chemical may have an 
effect in humans that is similar to an effect produced by a naturally 
occurring estrogen or other endocrine effects. However, there were no 
significant findings in other relevant toxicity tests, i.e., teratology 
and multi-generation reproduction studies, which would suggest that 
halosulfuron-methyl produces effects characteristic of the disruption 
of the estrogenic hormone.

C. Aggregate Exposure

    1. Dietary exposure. Tolerances have been established (40 CFR 
180.479) for residues of halosulfuron-methyl in or on a variety of 
plant and animal RACs including field corn at 0.05 ppm, grain sorghum 
(milo) at 0.05 ppm, sweet corn (kernel + cobs with husks removed) at 
0.05 ppm, pop corn grain at 0.05 ppm, sugarcane cane at 0.05 ppm, tree 
nuts nutmeat at 0.05 ppm, pistachio nuts nutmeat at 0.05 ppm, cotton 
undelinted seed at 0.05 ppm, and rice grain at 0.05 ppm; and secondary 
tolerances in meat and meat byproducts at 0.1 ppm (cattle, goats, hogs, 
horses, and sheep). Tolerances for the fruiting vegetable crop group 8 
have been proposed by Gowan Company at 0.05 ppm. An additional 
tolerance is herein being requested for the crop group 9B, squash/
cucumber subgroup of the cucurbit vegetable group, at 0.5 ppm.
    i. Food--a. Acute exposure. For purposes of assessing the potential 
dietary exposure from food under existing and proposed tolerances, 
aggregate exposure is based on the Theoretical Maximum Residue 
Contribution (TMRC) which is an estimate of the level of residues 
consumed daily if each food item contained pesticide residues equal to 
the tolerance. The calculated TMRC value using 95th percentile 
consumption data was 0.0036 mg/kg body weight/day or 0.72% acute 
reference dose (RfD) for the general US population; 0.0081 mg/kg/day or 
1.61% acute RfD for non-nursing infants less than 1 year old; and 
0.0022 mg/kg/day or 0.45% acute RfD for females 13+ years not pregnant 
or nursing. TMRC is obtained by multiplying the tolerance levels for 
each commodity by the daily consumption of the food forms of that 
commodity eaten by the U.S. population and various population 
subgroups. In conducting this exposure assessment, conservative 
assumptions were made, e.g., 100% of all commodities will contain 
halosulfuron-methyl residues and those residues would be at the level 
of their respective tolerances. This results in a large overestimate of 
human exposure. Given the conservative approach, dietary exposures to 
halosulfuron-methyl are less 2% acute RfD for all sub-populations. Food 
consumption data from DEEM software (Novigen Sciences, Inc., version 
6.73) were used in the calculation. Corn and sorghum forage and fodder 
are fed to animals; thus, exposure of humans to residues from these 
commodities might result if such residues are transferred to meat, 
milk, poultry or eggs. However, based on the results of animal 
metabolism and feeding studies and the amount of halosulfuron-methyl 
expected in animal feeds, it can be concluded that there is no 
reasonable expectation that residues of halosulfuron-methyl will exceed 
existing tolerances in meat.
    b. Chronic exposure. The chronic RfD is 0.1 mg/kg/day. The 
calculated TMRC value for the U.S. population is 0.0011 mg/kg/day or 
1.1% RfD; 0.0017 mg/kg/day or 1.7% cRfD for infants less than 1-year 
old; 0.0035 mg/kg/day or 3.5% cRfD for children 1-6 years old; and 
0.0009 mg/kg/day for 0.9% cRfD for females 13+ years not pregnant or 
nursing.
    c. Short- and intermediate-term exposure. The short-term NOAEL for 
females 13+ years and infants and children is 50 mg/kg/day. Comparing 
the NOAEL with the chronic food exposure from DEEM analysis of 0.0009 
mg/kg/day for females 13+ and 0.0035 mg/kg/day for children 1-6 years 
old results in food MOEs of 55,560 and 14,280, respectively. The 
intermediate-term NOAEL is 10 mg/kg/day, comparing the NOAEL with the 
chronic food exposure from DEEM analysis of 0.0035 mg/kg/day for 
children (1-6 years old) results in a food MOE of 2,860.
    d. Chronic risk-carcinogenic. Halosulfuron-methyl has been 
classified as a Group E chemical based upon the lack of evidence of 
carcinogenicity in mice and rats, and has been classified as a not 
likely human carcinogen.
    ii. Drinking water. There is no Maximum Contaminant Level (MCL) 
established for residues of halosulfuron-methyl. It is not listed for 
MCL development or drinking water monitoring under the Safe Drinking 
Water Act nor is it a target of EPA's National Survey of Wells for 
Pesticides. Monsanto is not aware of any halosulfuron-methyl detections 
in any wells, ponds, or lakes resulting from its use in the United 
States. The drinking water estimated environmental concentrations 
(EECs) in ground water (acute and chronic) is 0.008 mg/L. The EECs 
(acute and chronic) for surface water are 4.3 mg/L and 1.1 mg/L, 
respectively. These estimates are based on a maximum application rate 
of 0.063 lbs. active ingredient per acre which may be applied twice per 
season.
    a. Acute exposure and risk. Acute drinking water levels of concern 
(DWLOCs) have been calculated for exposure to halosulfuron-methyl in 
drinking water for the relevant population subgroups of females 13+ 
years and infants and children. The acute DWLOC is 15,000 mg/L for 
females 13+ years and 5,000 mg/L for infants and children. The 
calculated DWLOCs are significantly higher than the drinking water EECs 
for ground water (0.008 mg/L) and surface water (4.3 mg/L).
    b. Chronic exposure and risk. Chronic DWLOCs have been calculated 
for exposure to halosulfuron-methyl in drinking water for the U.S. 
population (48 contiguous states) and the relevant subgroups of females 
13+ years and infants and children. The chronic DWLOC is 3,500 mg/L for 
the U.S. population, 3,000 mg/L for females 13+ years, and 1,000 mg/L 
for infants and children. The calculated DWLOCs are significantly 
higher than the drinking water EECs for ground water (0.008 mg/L) and 
surface water (1.1 mg/L).
    c. Short- and intermediate-term exposure and risk. Short-term and 
intermediate-term DWLOCs have been calculated for exposure to 
halosulfuron-methyl in drinking water for the relevant population 
subgroups. The short-term DWLOC is 10,000 mg/L for females 13+ years 
and 3,700 mg/L for infants and children. The intermediate-term DWLOC is 
590 mg/L for adult males, 57 mg/L for females 13+ years, and 160 mg/L 
for infants and children. The calculated intermediate-term DWLOCs are 
significantly higher than

[[Page 51318]]

the chronic drinking water EECs for surface water (1.1 mg/L). The 
calculated short-term DWLOCs are significantly higher than the acute 
drinking water EECs for ground water (0.008 mg/L) and surface water 
(4.3 mg/L).
    d. Conclusion. Monsanto has concluded that potential levels of 
halosulfuron-methyl in soil and water do not appear to have significant 
toxicological effects on humans or animals and presents a negligible 
risk. Based on the very low level of mammalian toxicity, lack of other 
toxicological concerns and low use rates, there is reasonable certainty 
that no harm will result from exposure to halosulfuron-methyl via 
drinking water sources.
    2. Non-dietary exposure. Halosulfuron-methyl is labeled for use on 
commercial and residential turf and other non-crop sites. For 
residential applicators, short- and intermediate-term exposure may 
occur. Chronic exposure (>6 months of continuous exposure) are not 
expected.
    i. Acute exposure and risk. There is potential for exposure to 
halosulfuron-methyl by homeowner. However, since endpoints for acute 
dermal or inhalation were not identified, the use of halosulfuron-
methyl on residential non-food sites is not expected to pose an 
unacceptable acute risk.
    ii. Chronic exposure and risk. Chronic exposures for residential 
use of halosulfuron-methyl are not expected and a chronic non-dietary 
endpoint was not identified, therefore the use on residential non-food 
sites is not expected to pose an unacceptable chronic risk.
    iii. Short- and intermediate-term exposure and risk. There is 
potential for short- or intermediate-term dermal exposure to 
residential handlers; therefore, residential exposure assessments were 
conducted to assess the following post-application exposure scenarios: 
Dermal exposure to residues on turf; children's incidental non-dietary 
ingestion of residues on residential lawn from hand-to-mouth transfer; 
and children's ingestion of pesticide-treated turfgrass.
    The short-term dermal MOE for residential handlers is 4,200 which 
is significantly greater than the minimum acceptable MOE of 100.
    The short-term dermal MOE for exposure from treated lawns for adult 
males, adult females, and children are 390, 330, and 420, respectively, 
which are significantly greater than the minimum acceptable MOE of 100. 
The intermediate-term dermal MOE for exposure from treated lawns for 
adult males, adult females, and children are 120, 100, and 130, 
respectively, which are equal to or greater than the minimum acceptable 
MOE of 100. Therefore the use of halosulfuron-methyl on residential 
non-food sites is not expected to pose an unacceptable short- or 
intermediate-term risk.
    The short- and intermediate-term oral MOE for hand-to-mouth 
transfer for children are 4,900 and 1,500, respectively, which are 
significantly greater than the minimum acceptable MOE of 100. Therefore 
the use of halosulfuron-methyl on residential non-food sites is not 
expected to pose an unacceptable short- or intermediate-term risk.
    The short- and intermediate-term oral MOE for incidental ingestion 
by children are 210,000 and 66,000, respectively, which are 
significantly greater than the minimum acceptable MOE of 100. Therefore 
the use on residential non-food sites is not expected to pose an 
unacceptable short- or intermediate-term risk.

D. Cumulative Effects

    Halosulfuron-methyl belongs to the sulfonyl urea class of 
chemistry. The mode of action of halosulfuron-methyl is the inhibition 
of the plant enzyme aceto lactase synthetase (ALS), which is essential 
for the production of required amino acid in plants. Although other 
registered sulfonyl ureas may have similar herbicidal mode of action, 
there is no information available to suggest that these compounds 
exhibit a similar toxicity profile in the mammalian system that would 
be cumulative with halosulfuron-methyl. Thus, consideration of a common 
mechanism of toxicity is not appropriate at this time. Monsanto is 
considering only the potential risks of halosulfuron-methyl in its 
aggregate exposure assessment.

E. Safety Determination

    1. U.S. population--i. Acute risk. Aggregate exposure risk includes 
exposure from food and water. The risk from acute ``food only'' 
exposure is less than 2% of the RfD for all population groups which is 
less than the EPA's level of concern. The lowest DWLOC calculated was 
5,000 mg/L for infants and children. The calculated DWLOC for females 
(13+ years) was 15,000 mg/L. For both subgroups, the DWLOC is 
significantly higher than the drinking water EECs for acute ground 
water (0.008 mg/L) and surface water (4.3 mg/L). Therefore, the risk 
from aggregate exposure to halosulfuron-methyl residues from all 
anticipated dietary exposure routes does not pose appreciable risks to 
human health.
    ii. Chronic risk. Aggregate chronic exposure to halosulfuron-methyl 
from ``food only'' exposure utilizes 3.5% of the RfD for the most 
sensitive subgroup, children (1-6 years). The lowest DWLOC calculated 
was 1,000 mg/L for infants and children which is significantly higher 
than the drinking water EECs for chronic ground water (0.008 mg/L) and 
surface water (1.1 mg/L). Therefore, the aggregate risk from chronic 
exposure to halosulfuron-methyl residues from all anticipated dietary 
exposures does not pose appreciable risks to human health.
    iii. Short- and intermediate-term risk--a. Short-term aggregate 
exposure takes into account chronic dietary food and water plus short-
term residential exposure. For halosulfuron-methyl, EPA has determined 
that it is appropriate to aggregate exposure via oral exposure route 
(food and water) with those via oral and dermal exposure routes from 
residential uses. The MOEs for ``food only'' and residential exposure 
routes are 22,400 and 330 for females 13+ years. Short-term DWLOC for 
females 13+ is 10,000 mg/L which is substantially higher than the 
drinking water EECs for acute surface water (4.3 mg/L). The food only 
and residential (oral and dermal) MOEs are well above the acceptable 
short-term aggregate MOE of 100. Therefore, exposure to halosulfuron-
methyl residues resulting from current and proposed uses does not pose 
a short-term aggregate risk.
    b. Intermediate-term aggregate exposure takes into account chronic 
dietary food and water plus intermediate-term residential exposure. The 
MOEs for ``food only'' and residential exposure routes are 13,700 and 
120 for adult males, and 11,500 and 100 for females 13+ years. The 
intermediate-term DWLOCs are 590 mg/L and 57 mg/L, respectively, for 
adult males and females 13+. Intermediate-term DWLOCs are substantially 
higher than the drinking water EECs for chronic surface water (1.1 mg/
L). The food only and residential (dermal) MOEs are above the 
acceptable short-term aggregate MOE of 100. Therefore, exposure to 
halosulfuron-methyl residues resulting from current and proposed uses 
does not pose a intermediate-term aggregate risk.
    iv. Aggregate cancer risk. Halosulfuron-methyl has been classified 
as a Group E chemical based upon the lack of evidence of 
carcinogenicity in mice and rats, and has been classified as a not 
likely human carcinogen.
    v. Conclusion. Based upon these risk assessments, Monsanto 
concluded that there is a reasonable certainty that no harm will result 
from aggregate exposure to halosulfuron-methyl

[[Page 51319]]

residues resulting from current and proposed uses.
    2. Infants and children--i. Safety factor. FFDCA section 408 
provides that EPA may apply an additional safety factor (up to 10) in 
the case of threshold effects for infants and children to account for 
prenatal and postnatal toxicity and the completeness of the data base. 
Except for the pending request for a developmental neurotoxicity study, 
the toxicity data base is complete for halosulfuron-methyl. Based upon 
reliable toxicity data, the use of an additional 10x safety factor is 
not warranted. Dietary assessments do not indicate a level of concern 
for potential risks to infants and children based upon the low use 
rates of halosulfuron-methyl and that the results of field and animal 
RAC studies conclude that detectable residues are not expected in human 
foods.
    ii. Acute risk. The acute RfD was determined to be 0.5 mg/kg/day 
based upon the developmental rabbit study. The percent of the acute RfD 
occupied is 0.72% for the U.S. population, 0.45% for females 13+ years 
not pregnant or nursing, and 1.61% for non-nursing infants (1 year 
old). The subgroup with the highest exposure were non-nursing infants 
and children. The DWLOC for acute exposure for infants and children is 
5,000 mg/L and is significantly less than the maximum concentration of 
halosulfuron-methyl in drinking water (0.008 mg/L in ground water and 
4.3 mg/L in surface water).
    iii. Chronic risk. The cRfD was determined to be 0.1 mg/kg/day 
based upon the chronic dog study. The percent of RfD occupied is 3.5% 
for the most sensitive subgroup, children (1-6 years old). The DWLOC 
for chronic exposure for infants and children is 1,000 mg/L and is 
significantly less than the maximum concentration of halosulfuron-
methyl in drinking water (0.008 mg/L in ground water and 1.1 mg/L in 
surface water).
    iv. Short- and intermediate-term risk. An aggregate exposure 
estimate and risk assessment was calculated for post-application 
exposure to halosulfuron-methyl from treated lawns. Short-term MOEs for 
food, residential oral, and residential dermal are 6,200, 4,900, and 
420, respectively, for infants and children. Intermediate-term MOEs for 
food, residential oral, and residential dermal are 2,900, 1,500, and 
130, respectively, for children and infants. The short- and 
intermediate-term DWLOCs for infants and children were 3,700 and 160 
mg/L, respectively, which are substantially higher than the drinking 
water EECs for acute surface water (4.3 mg/L) and chronic surface water 
(1.1 mg/L).
    v. Conclusion. Therefore, based on complete and reliable toxicity 
data and the conservative exposure assessment, Monsanto concludes that 
there is reasonable certainty that no harm will result to infants and 
children from aggregate exposure to halosulfuron-methyl residues with 
respect to the proposed new uses on squash/cucumber subgroup of the 
cucurbit vegetable group.

F. International Tolerances

    Maximum residue levels have not been established for residues of 
halosulfuron-methyl on any food or feed crop by the Codex Alimentarius 
Commission.

[FR Doc. 00-20997 Filed 8-22-00; 8:45 am]
BILLING CODE 6560-50-F