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Prosulfuron (Syngenta). December 31, 2002. Petition for pesticide tolerances. Federal Register/


http://www.epa.gov/EPA-PEST/2002/December/Day-31/p32988.htm


[Federal Register: December 31, 2002 (Volume 67, Number 251)]
[Notices]
[Page 79914-79918]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr31de02-56]

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ENVIRONMENTAL PROTECTION AGENCY
[OPP-2002-0343; FRL-7284-7]
 
Prosulfuron; Notice of Filing Pesticide Petitions to Establish 
Tolerances 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 pesticide 
petitions proposing the establishment of regulations for residues of 
prosulfuron in or on various food commodities.

DATES: Comments, identified by docket ID number OPP-2002-0343, must be 
received on or before January 30, 2003.

ADDRESSES: Comments may be submitted electronically, by mail, or 
through hand delivery/courier. Follow the detailed instructions as 
provided in Unit I. of the SUPPLEMENTARY INFORMATION.

FOR FURTHER INFORMATION CONTACT: Jim Tompkins, Registration Division 
(7505C), Office of Pesticide Programs, Environmental Protection Agency, 
1200 Pennsylvania Ave., NW., Washington, DC 20460-0001; telephone 
number: (703) 305-5697; e-mail address: tompkins.jim@epa.gov.

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:
     Crop production (NAICS code 111)
     Animal production (NAICS code 112)
     Food manufacturing (NAICS code 311)
     Pesticide manufacturing (NAICS code 32532)
    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 this unit could also be 
affected. The North American Industrial Classification System (NAICS) 
codes have been provided to assist you and others in determining 
whether 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 Copies of this Document and Other Related Information?

    1. Docket. EPA has established an official public docket for this 
action under docket identification (ID) number OPP-2002-0343. The 
official public docket consists of the documents specifically 
referenced in this action, any public comments received, and other 
information related to this action. Although a part of the official 
docket, the public docket does not include Confidential Business 
Information (CBI) or other information whose disclosure is restricted 
by statute. The official public docket is the collection of materials 
that is available for public viewing at the Public Information and 
Records Integrity Branch (PIRIB), Rm. 119, Crystal Mall #2, 
1921 Jefferson Davis Hwy., Arlington, VA. This docket facility is open 
from 8:30 a.m. to 4 p.m., Monday through Friday, excluding legal 
holidays. The docket telephone number is (703) 305-5805.
    2. Electronic access. You may access this Federal Register document 
electronically through the EPA Internet under the ``Federal Register'' 
listings at http://www.epa.gov/fedrgstr/.
    An electronic version of the public docket is available through 
EPA's

[[Page 79915]]

electronic public docket and comment system, EPA Dockets. You may use 
EPA Dockets at http://www.epa.gov/edocket/ to submit or view public 
comments, access the index listing of the contents of the official 
public docket, and to access those documents in the public docket that 
are available electronically. Although not all docket materials may be 
available electronically, you may still access any of the publicly 
available docket materials through the docket facility identified in 
Unit I.B.1. Once in the system, select ``search,'' then key in the 
appropriate docket ID number.
    Certain types of information will not be placed in the EPA Dockets. 
Information claimed as CBI and other information whose disclosure is 
restricted by statute, which is not included in the official public 
docket, will not be available for public viewing in EPA's electronic 
public docket. EPA's policy is that copyrighted material will not be 
placed in EPA's electronic public docket but will be available only in 
printed, paper form in the official public docket. To the extent 
feasible, publicly available docket materials will be made available in 
EPA's electronic public docket. When a document is selected from the 
index list in EPA Dockets, the system will identify whether the 
document is available for viewing in EPA's electronic public docket. 
Although not all docket materials may be available electronically, you 
may still access any of the publicly available docket materials through 
the docket facility identified in Unit I.B. EPA intends to work towards 
providing electronic access to all of the publicly available docket 
materials through EPA's electronic public docket.
    For public commenters, it is important to note that EPA's policy is 
that public comments, whether submitted electronically or in paper, 
will be made available for public viewing in EPA's electronic public 
docket as EPA receives them and without change, unless the comment 
contains copyrighted material, CBI, or other information whose 
disclosure is restricted by statute. When EPA identifies a comment 
containing copyrighted material, EPA will provide a reference to that 
material in the version of the comment that is placed in EPA's 
electronic public docket. The entire printed comment, including the 
copyrighted material, will be available in the public docket.
    Public comments submitted on computer disks that are mailed or 
delivered to the docket will be transferred to EPA's electronic public 
docket. Public comments that are mailed or delivered to the docket will 
be scanned and placed in EPA's electronic public docket. Where 
practical, physical objects will be photographed, and the photograph 
will be placed in EPA's electronic public docket along with a brief 
description written by the docket staff.

C. How and To Whom Do I Submit Comments?

    You may submit comments electronically, by mail, or through hand 
delivery/courier. To ensure proper receipt by EPA, identify the 
appropriate docket ID number in the subject line on the first page of 
your comment. Please ensure that your comments are submitted within the 
specified comment period. Comments received after the close of the 
comment period will be marked ``late.'' EPA is not required to consider 
these late comments. If you wish to submit CBI or information that is 
otherwise protected by statute, please follow the instructions in Unit 
I.D. Do not use EPA Dockets or e-mail to submit CBI or information 
protected by statute.
    1. Electronically. If you submit an electronic comment as 
prescribed in this unit, EPA recommends that you include your name, 
mailing address, and an e-mail address or other contact information in 
the body of your comment. Also include this contact information on the 
outside of any disk or CD ROM you submit, and in any cover letter 
accompanying the disk or CD ROM. This ensures that you can be 
identified as the submitter of the comment and allows EPA to contact 
you in case EPA cannot read your comment due to technical difficulties 
or needs further information on the substance of your comment. EPA's 
policy is that EPA will not edit your comment, and any identifying or 
contact information provided in the body of a comment will be included 
as part of the comment that is placed in the official public docket, 
and made available in EPA's electronic public docket. If EPA cannot 
read your comment due to technical difficulties and cannot contact you 
for clarification, EPA may not be able to consider your comment.
    i. EPA Dockets. Your use of EPA's electronic public docket to 
submit comments to EPA electronically is EPA's preferred method for 
receiving comments. Go directly to EPA Dockets at http://www.epa.gov/edocket
, and follow the online instructions for submitting comments. 
Once in the system, select ``search,'' and then key in docket ID number 
OPP-2002-0343. The system is an ``anonymous access'' system, which 
means EPA will not know your identity, e-mail address, or other contact 
information unless you provide it in the body of your comment.
    ii. E-mail. Comments may be sent by e-mail to opp-docket@epa.gov, 
Attention: Docket ID Number OPP-2002-0343. In contrast to EPA's 
electronic public docket, EPA's e-mail system is not an ``anonymous 
access'' system. If you send an e-mail comment directly to the docket 
without going through EPA's electronic public docket, EPA's e-mail 
system automatically captures your e-mail address. E-mail addresses 
that are automatically captured by EPA's e-mail system are included as 
part of the comment that is placed in the official public docket, and 
made available in EPA's electronic public docket.
    iii. Disk or CD ROM. You may submit comments on a disk or CD ROM 
that you mail to the mailing address identified in Unit I.C.2. These 
electronic submissions will be accepted in WordPerfect or ASCII file 
format. Avoid the use of special characters and any form of encryption.
    2. By mail. Send your comments to: Public Information and Records 
Integrity Branch (PIRIB) (7502C), Office of Pesticide Programs (OPP), 
Environmental Protection Agency, 1200 Pennsylvania Ave., NW., 
Washington, DC 20460-0001, Attention: Docket ID Number OPP-2002-0343.
    3. By hand delivery or courier. Deliver your comments to: Public 
Information and Records Integrity Branch (PIRIB), Office of Pesticide 
Programs (OPP), Environmental Protection Agency, Rm. 119, Crystal Mall 
#2, 1921 Jefferson Davis Hwy., Arlington, VA, Attention: Docket 
ID Number OPP-2002-0343. Such deliveries are only accepted during the 
docket's normal hours of operation as identified in Unit I.B.1.

D. How Should I Submit CBI To the Agency?

    Do not submit information that you consider to be CBI 
electronically through EPA's electronic public docket or by e-mail. You 
may claim information that you submit to EPA as CBI by marking any part 
or all of that information as CBI (if you submit CBI on disk or CD ROM, 
mark the outside of the disk or CD ROM as CBI and then identify 
electronically within the disk or CD ROM the specific information that 
is 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

[[Page 79916]]

docket and EPA's electronic public docket. If you submit the copy that 
does not contain CBI on disk or CD ROM, mark the outside of the disk or 
CD ROM clearly that it does not contain CBI. Information not marked as 
CBI will be included in the public docket and EPA's electronic public 
docket without prior notice. If you have any questions about CBI or the 
procedures for claiming CBI, please consult the person listed 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 
ID 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 FFDCA 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 20, 2002.
 Debra Edwards,
Acting Director, Registration Division, Office of Pesticide Programs.

Summary of Petitions

    The petitioner's summary of the pesticide petitions is printed 
below as required by FFDCA section 408(d)(3). The summary of the 
petitions was prepared by the petitioner and represents the view of the 
petitioner. The petitions 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.
    EPA has received pesticide petitions (PP 5F4469) and (PP 4F4336), 
from Syngenta Crop Protection, Inc., P.O. Box 18300, Greensboro, NC 
27419-8300 proposing, pursuant to section 408(d) of the Federal Food, 
Drug, and Cosmetic Act (FFDCA), 21 U.S.C. 346a(d), to amend 40 CFR part 
180 by establishing a tolerance for residues of prosulfuron, 1-(4-
methoxy-6-methyl-triazin-2-yl)-3-[2-(3,3,3-trifluoropropyl)-
phenylsulfonyl]-urea in or on the raw agricultural commodities, cereal 
grains group (except rice and wild rice) grain at 0.01 parts per 
million (ppm), cereal grains group (except rice and wild rice) forage 
at 0.10 ppm, cereal grains group (except rice and wild rice) fodder at 
0.01 ppm, cereal grains group (except rice and wild rice) straw at 0.02 
ppm, cereal grains group (except rice and wild rice) hay at 0.20 ppm, 
milk at 0.01 ppm, meat, fat, kidney, liver, and meat by-products of 
cattle, goats, hogs, horses, and sheep at 0.05 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 is a revised notice of filing to amend a previous notice of 
filing published in the Federal Register of August 25, 1999 (FR 64 
46382) (FRL-6093-7), to propose permanent tolerances, instead of the 
current time-limited tolerances for prosulfuron.

A. Residue Chemistry

    1. Plant metabolism. The nature of the residue of prosulfuron in 
corn is adequately understood. Significant pathways involve oxidation 
of the phenyl ring to give 5-hydroxy prosulfuron, which is followed by 
sugar conjugation. Hydrolytic cleavage of the sulfonylurea bridge 
occurs for both prosulfuron and 5-hydroxy prosulfuron, yielding the 
corresponding sulfonamide and triazine amine moieties. The sulfonamide 
metabolites are subsequently conjugated with sugars. Demethylation of 
the triazine amine results in the formation of the corresponding 
hydroxy triazine, which is further hydrolyzed at the amino group to 
form the dihydroxy triazine.
    2. Analytical method. Adequate analytical methods exist for the 
detection and measurement of residue levels of prosulfuron in or on raw 
and processed commodities of cereal grains, and for meat, milk and 
eggs. The limit of quantitation (LOQ) is 0.01 ppm for crop commodities, 
processed fractions and milk, and 0.05 ppm for meat and eggs. The 
method is based on commodity-specific cleanup procedures followed by 
determination by high performance liquid chromatography with 
ultraviolet (UV) detection.
    3. Magnitude of residues. Complete, full geography residue 
programs, including processing, have been conducted on corn, wheat and 
grain sorghum. A three-level dairy animal feeding study to determine 
the transfer of residues of prosulfuron from animal feed commodities to 
meat and milk has also been conducted.

B. Toxicological Profile

    1. Acute toxicity. EPA has set an acute reference dose of 0.1 
milligram/kilogram/day (mg/kg/day) based upon a no observed adverse 
effect level (NOAEL) of 10 mg/kg/day from the rat acute neurotoxicity 
study (lowest observed adverse effect level (LOAEL) of 250 mg/kg/day 
due to reduced motor activity and body temperature in males and 
impaired righting reflex in females) and a 100-fold uncertainty factor 
(UF).
    2. Genotoxicty. Prosulfuron was negative for mutagenic/genotoxic 
effects when tested in a bacterial reverse gene mutation assay with and 
without metabolic activation using different S. typhimurium and E. coli 
stains; in a mammalian gene mutation study using V79 cells; in an in 
vitro mammalian cytogenetic test using Chinese hamster ovary (CHO) 
cells with and without metabolic activation; in a micronucleus test in 
mice; and in a DNA- repair using freshly isolated rat liver 
hepatocytes.
    3. Reproductive and developmental toxicity. The data base on 
prosulfuron relative to prenatal and postnatal effects for children is 
considered to be essentially complete with no data gaps. The 
developmental and reproductive toxicity data do not indicate increase 
susceptibility of rats or rabbits to in utero and/or postnatal exposure 
to

[[Page 79917]]

prosulfuron. In a rat teratology study, evidence of maternal toxicity 
(decreased body weight gain and reduced food consumption) and 
developmental toxicity (increased incidence of skeletal variations that 
was not significantly different from the historical control) was found 
at the maximum tolerated dose of 400 mg/kg. There was no evidence of 
teratogenicity at any dose, and the maternal and developmental NOAELs 
were established at 200 mg/kg. In a rabbit teratology study, maternal 
toxicity (decreased body weight gain and reduced food consumption) was 
observed in the 100 mg/kg dose group. There was no evidence of 
teratogenicity at any dose. Since a range-finding rabbit teratology 
study had seen additional clinical findings and fetotoxicity at 
maternally toxic doses (>=150 mg/kg) but not in the definitive study at 
up to 100 mg/kg, a second rabbit teratology study was conducted at 
doses of 0, 20, 100, and 200 mg/kg/day. Maternal toxicity was observed 
at 200 mg/kg. The developmental NOAEL was 100 mg/kg and the maternal 
NOAEL was 20 mg/kg in this study. There was no evidence of 
teratogenicity at any dose. A rat multigenerational reproduction study 
indicated reproductive and systemic NOAELs of 13.3 mg/kg/day based on 
decreased mean body weights and body weight gain observed at 136 mg/kg/
day for both pups and parental animals. No treatment-related effects on 
reproductive performance (i.e., to produce, deliver or raise litters), 
litter sizes, viability of pups, and necropsy findings in parental 
animals and offspring were noted up to the highest dose level.
    4. Subchronic toxicity. The liver was identified as a target organ 
at high doses in the rat, mouse, and dog as indicated by slightly 
increased liver enzymes and liver weights. No histomorphologic 
correlates of liver damage was noted in the 90-day studies except in 
the mouse study where centrilobular hypertrophy was found in males at 
feeding levels >=1,750 ppm and in females at levels >=3,500 ppm. In 
general, NOAELs for target organ effects were established at doses that 
were much higher than overall study NOAELs, which were based on other 
indicators of toxicity such body weight gain.
    5. Chronic toxicity. In the 1-year dog chronic dosing study, the 
NOAEL was 1.84 mg/kg/day based on hematologic and clinical chemistry 
effects and incidence of lipofuscin accumulation in the liver at 18.6 
mg/kg/day. In the 18-month mouse carcinogenicity study, there was no 
evidence of carcinogenic effects up to the highest dose tested (HDT) of 
1,062 mg/kg/day. The NOAEL was 1.71 mg/kg/day in males, and 100 mg/kg/
day in females based on increased incidence/severity of centrilobular 
hepatocellular hypertrophy. A 2-year chronic feeding/carcinogenicity 
study in rats indicated systemic NOAEL of 7.9 mg/kg/day was based on 
decreased body weight and body weight gain, hematopoietic effects 
(males), and possibly increased serum GGT and decreased liver, kidney, 
and adrenal weights (females) at 79.9 mg/kg/ day. There was uncertain 
evidence of carcinogenicity with slight increases in the incidence of 
mammary gland adenocarcinomas in females at 95.7 and 205.8 mg/kg/day, 
slight increase in incidence of benign testicular interstitial cell 
tumors at 79.9 and 160.9 mg/kg/day (significant trend only). 
Considering the weight of the evidence, the EPA Reference Dose 
Committee previously concluded that the chemical should be classified 
as a Group D carcinogen (inadequate evidence), not classifiable as to 
human carcinogenicity. The HIARC (meeting December 2, 1999) accepted 
the previous conclusions and updated the cancer classification to the 
new classification: ``data are inadeqate,'' with no new studies 
required. EPA has set a chronic reference dose of 0.02 mg/kg based on a 
NOAEL of 1.84 mg/kg in a dog feeding study and a 100-fold UF.
    6. Animal metabolism. The metabolic pathways in the rat, goat, and 
hen are similar and are adequately understood. Prosulfuron is rapidly 
absorbed from the gastrointestinal (GI) tract of rats and is rapidly 
excreted. Approximately 90% of the administered dose is excreted during 
the first 48 hours, predominately via urine. Tissue residues are low. 
Prosulfuron is metabolized primarily via hydroxylation at side chain 
and phenyl ring positions and O-demethylation of the triazyl methoxy 
group. Minor pathways include unsaturation of the trifluoropropyl side 
chain, hydrolysis of the phenylsulfonylurea bridge and oxidative/
hydrolytic cleavage of the triazine ring system. In the goat, the 
orally administered prosulfuron is quickly eliminated primarily via the 
urine as prosulfuron. The metabolism of prosulfuron in the goat follows 
a similar pathway as observed in the rat although not as extensive. The 
majority of the residues were accounted for as prosulfuron, the 
triazine amine, which results from bridge hydrolysis (CGA-150829) and 
the triazinyl hydroxymethyl metabolite (CGA-273437). In the hen, 
metabolism is similar to that observed in the rat and goat. The major 
residues found in edible tissues and eggs were prosulfuron, the 
triazine amine (CGA-150829), and the sulfonamide (CGA-159902) which 
results from hydrolysis of the sulfonylurea bridge.
    7. Metabolite toxicology. Metabolic pathways of prosulfuron in 
plants and animals are comparable and no detectable residues are found 
in or on crops. All relevant plant metabolites are observed in the 
animals and are thus toxicologically covered. The remaining plant 
metabolites are toxicologically insignificant. Therefore, parent 
prosulfuron is the appropriate compound for the tolerance expression 
and analytical monitoring.
    8. Endocrine disruption. Prosulfuron does not belong to a class of 
chemicals known for having significant adverse effects on the endocrine 
system. Developmental toxicity studies in rats and rabbits and 
reproduction study in rats gave no indication that prosulfuron might 
have any effects on endocrine function related to development and 
reproduction. The subchronic and chronic studies also showed no 
evidence of a long-term effect related to the endocrine system.

C. Aggregate Exposure

    1. Dietary exposure. Acute and chronic dietary exposure assessments 
were conducted for prosulfuron using tolerance values published in 40 
CFR 180.481. In both assessments it was assumed that 100% of all corn 
and cereal grains were treated with prosulfuron (100% market share). 
The exposure analyses was conducted using food consumption data from 
USDA's 1994-1996 Continuing Survey of Intake by Individuals (CSFII) and 
Novigen Sciences, Inc. Dietary Exposure Evaluation Model (DEEM).
    i. Food. Chronic exposure was compared to a RfD of 0.02 mg/kg based 
on a NOAEL of 1.84 mg/kg in a dog feeding study and a 100-fold UF. This 
exposure analysis showed that the U.S. population had an exposure of 
less than 1% of the chronic RfD. The most sensitive subpopulation was 
children (1-6 years old) with a chronic exposure of 2.4%. Acute 
exposure was compared to an acute RfD of 0.1 mg/kg, which was based on 
a NOAEL of 10 mg/kg from an acute neurotoxicity study in the rat and a 
100-fold UF. The most sensitive subpopulation was all infants with an 
exposure of 2.2% of the acute RfD. The U.S. population showed an 
exposure of 1.5% of the RfD. These results show that there is more than 
a reasonable certainty of no harm, through exposure to prosulfuron 
residues in the diet.
    ii. Drinking water. For estimated surface water concentrations 
using generic expected environmental concentration (GENEEC), the peak 
day-

[[Page 79918]]

0 estimate, 1.86 parts per billion (ppb), was used in the acute 
exposure analysis and the corrected 56-day drinking water concentration 
of 0.4667 ppb was used in the chronic exposure analysis. The SCI-GROW 
estimated ground water concentration for the prosulfuron uses of 
0.406585 ppb contributed little to the overall exposure. The acute 
drinking water levels of concern (DWLOC) for prosulfuron were based on 
the acute RfD, a margin of exposure (MOE), the 99.9th 
percentile of the acute dietary exposure for U.S. population subgroups 
and the body weight - daily water consumption of each respective 
subgroup. The calculated acute DWLOC values for the population 
subgroups ranged from 978-3447 ppb. The estimated ground water 
concentration (0.406585 ppb) and the peak day-0 surface water 
concentration (1.86 ppb) of prosulfuron did not exceed the acute DWLOC 
values. The chronic (non-cancer) DWLOC for prosulfuron were based on 
the chronic RfD, any estimated residential exposure, the chronic 
dietary exposure for select U.S. population subgroups and the body 
weight - daily water consumption of each respective subgroup. The 
calculated chronic DWLOC values for the population subgroups ranged 
from 197-694. The estimated ground water concentration (0.406585 ppb) 
and the corrected average 56-day surface water concentration (0.4667 
ppb) of prosulfuron did not exceed the chronic DWLOC values. Therefore, 
there is reasonable certainty that the residues of prosulfuron in the 
drinking water would not result in unacceptable levels of acute or 
chronic aggregate human health risk, and that such exposure would not 
exceed the exposure allowable by the risk cup.
    Nondietary exposure. Nondietary exposure to prosulfuron is 
considered negligible as the chemical is registered for agricultural 
use only. For workers handling this chemical, acceptable MOE (in the 
range of thousands) have been obtained for both acute and chronic 
scenarios.

D. Cumulative Effects

    Consideration of a common mechanism of toxicity is not appropriate 
at this time since there is no information to indicate that toxic 
effects produced by prosulfuron would be cumulative with those of any 
other types of chemicals.

E. Safety Determination

    1. U.S. population. The calculation shows that less than 1% of the 
RfD will be utilized for the U.S. population based on chronic toxicity 
endpoints. EPA generally has no concern for exposures below 100% of the 
RfD because the RfD represents the level at or below which daily 
aggregate dietary exposure over a lifetime will not pose appreciable 
risks to human health. It is concluded that there is a reasonable 
certainty that no harm will result from aggregate exposure to 
prosulfuron residue.
    2. Infants and children. The calculated percent of the RfD that 
will be utilized by aggregate exposure to residues of prosulfuron is 
only 2.4% for children (1 to 6 years old), the most impacted 
subpopulation. There were no adverse reproductive or developmental 
effects indicated in the prosulfuron toxicity data base, which is 
considered to be essentially complete with no data gaps. It is 
concluded that there is a reasonable certainty that no harm will result 
to infants and children from aggregate exposure to prosulfuron 
residues.

F. International Tolerances

    No codex MRLs have been established for residues of prosulfuron.
[FR Doc. 02-32988 Filed 12-30-02; 8:45 am]
BILLING CODE 6560-50-S