Reregistration Eligibility Decision 

for 

Chlorsulfuron 

May 20, 2005 
Reregistration Eligibility Decision 

for 

Chlorsulfuron 

Case No. 0631 
Reregistration Eligibility Decision (RED) for 

Chlorsulfuron 

List A 

Case No. 0631 

Approved by: ________________________________ 

Debra Edwards, Ph.D., Director 

Special Review and Reregistration Division 

Date: May 20, 2005 
TABLE OF CONTENTS 

EXECUTIVE SUMMARY ...................................................... v

I. Introduction ............................................................. 1

II. Chemical Overview ....................................................... 2

A. Regulatory History .................................................. 2

B. Chemical Identification ............................................... 3

C. Use Profile ......................................................... 4

D. Estimated Usage of Pesticide .......................................... 5

III. Summary of Chlorsulfuron Risk Assessment .................................. 6

A. Human Health Risk Assessment ....................................... 7

1. Occupational Exposure and Risk .................................. 7

a. Toxicity .................................................. 7

b. Occupational Exposure ..................................... 8

c. Occupational Handler Risk Summary ......................... 9

d. Post-Application Exposure and Risk ......................... 11

2. Incident Reports .............................................. 11

B. Environmental Risk Assessment ...................................... 11

1. Environmental Fate and Transport ................................ 12

2. Ecological Risk Assessment ..................................... 12

a. Ecological Hazard Profile .................................. 13

b. Environmental Exposure to Non-Target Organisms ............. 16

c. Environmental Risk to Non-Target Organisms ................. 17

d. Endangered/Threatened Species ............................ 22

e. Ecological Incident Reports ................................ 25

IV. Risk Management and Reregistration Decision ............................... 26

A. Determination of Reregistration Eligibility .............................. 26

B. Summary of Public Comments ........................................ 27

C. Regulatory Position ................................................. 27

1. FQPA Assessment ............................................. 27

a. “Risk Cup” Determination ................................. 27

b. Endocrine Disruptor Effects ................................ 28

c. Tolerance Summary ....................................... 28

2. Benefits Discussion ............................................ 28

D. Regulatory Rationale ............................................... 29

1. Human Health Risk Mitigation .................................. 30

a. Dietary, Homeowner and Aggregate Mitigation ................ 30

b. Occupational Risk Mitigation ............................... 30

2. Environmental Risk Mitigation .................................. 30
3. Other Labeling ................................................ 32

a. Endangered Species Statement .............................. 32

b. Spray Drift Management .................................. 33

V. What Registrants Need to Do ............................................. 33

A. Manufacturing Use Products ......................................... 33

1. Additional Generic Data Requirements ............................ 33

2. Labeling for Manufacturing-Use Products .......................... 34

B. End-Use Products .................................................. 34

1. Additional Product-Specific Data Requirements ..................... 34

2. Labeling for End-Use Products ................................... 34

C. Labeling Changes Summary Table ..................................... 34

VI. Related Documents and How to Access Them ................................ 41
CHLORSULFURON REREGISTRATION TEAM 

Office of Pesticide Programs: 

Health Effects Risk Assessment 

Susan Hanley 

Felicia Fort 

Environmental Fate and Effects Risk Assessment 

Kevin Costello 

Brian Kiernan 

Norman Birchfield 

Use and Usage Analysis 

Nicole Zinn 

Jin Kim 

Registration Support 

Erik Kraft 

Philip Errico 

Risk Management 

Susan Jennings 

i 
GLOSSARY OF TERMS AND ABBREVIATIONS

a.i. Active Ingredient 

AGDCI Agricultural Data Call-In 

AR Anticipated Residue 

BCF Bioconcentration Factor 

CAS Chemical Abstracts Service 

CNS Central Nervous System 

CSF Confidential Statement of Formula 

CFR Code of Federal Regulations 

CSFII USDA Continuing Surveys for Food Intake by Individuals 

DCI Data Call-In 

DEEM Dietary Exposure Evaluation Model 

DFR Dislodgeable Foliar Residue 

DRES Dietary Risk Evaluation System 

DWLOC Drinking Water Level of Comparison. 

EC Emulsifiable Concentrate Formulation 

EEC Estimated Environmental Concentration. The estimated pesticide concentration in an 

environment, such as a terrestrial ecosystem. 

EP End-Use Product 

EPA U.S. Environmental Protection Agency 

FAO Food and Agriculture Organization 

FDA Food and Drug Administration 

FIFRA Federal Insecticide, Fungicide, and Rodenticide Act 

FFDCA Federal Food, Drug, and Cosmetic Act 

FQPA Food Quality Protection Act 

GENEEC Tier I Surface Water Computer Model 

GLC Gas Liquid Chromatography 

GLN Guideline Number 

GM Geometric Mean 

GRAS Generally Recognized as Safe as Designated by FDA 

HDT Highest Dose Tested 

IR Index Reservoir 

LC50 Median Lethal Concentration. A statistically derived concentration of a substance that 

can be expected to cause death in 50% of test animals. It is usually expressed as the 

weight of substance per weight or volume of water, air or feed, e.g., mg/l, mg/kg or 

ppm. 

LD50 Median Lethal Dose. A statistically derived single dose that can be expected to cause 

death in 50% of the test animals when administered by the route indicated (oral, dermal, 

inhalation). It is expressed as a weight of substance per unit weight of animal, e.g., 

mg/kg. 

ii 
LEL Lowest Effect Level 

LOC Level of Concern 

LOD Limit of Detection 

LOAEL Lowest Observed Adverse Effect Level 

MATC Maximum Acceptable Toxicant Concentration 

MCLG Maximum Contaminant Level Goal (MCLG) The MCLG is used by the Agency to 

regulate contaminants in drinking water under the Safe Drinking Water Act. 

mg/kg/day Milligram Per Kilogram Per Day 

mg/L Milligrams Per Liter 

MOE Margin of Exposure 

MP Manufacturing-Use Product 

MRID Master Record Identification (number). EPA's system of recording and tracking 

studies submitted. 

NA Not Applicable 

N/A Not Applicable 

NAWQA USGS National Water Quality Assessment 

NOEC No Observed Effect Concentration 

NOEL No Observed Effect Level 

NOAEL No Observed Adverse Effect Level 

NPDES National Pollutant Discharge Elimination System 

NR Not Required 

OPP EPA Office of Pesticide Programs 

OPPTS EPA Office of Prevention, Pesticides and Toxic Substances 

Pa Pascal, unit measuring atmosphere pressure. 

PAD Population Adjusted Dose 

PADI Provisional Acceptable Daily Intake 

PAG Pesticide Assessment Guideline 

PAM Pesticide Analytical Method 

PCA Percent Crop Area 

PDP USDA Pesticide Data Program 

PHED Pesticide Handler's Exposure Data 

PHI Preharvest Interval 

ppb Parts Per Billion 

PPE Personal Protective Equipment 

ppm Parts Per Million 

PRN Pesticide Registration Notice 

PRZM/ 

EXAMS Tier II Runoff/Surface Water Computer Models 

Q1 * Unit Risk of Carcinogenic Potential of a Compound, Quantified by the EPA's Linear 

Low Dose Cancer Risk Model 

RAC Raw Agriculture Commodity 

iii 
RBC Red Blood Cell 

RED Reregistration Eligibility Decision 

REI Restricted Entry Interval 

RfD Reference Dose 

RQ Risk Quotient 

RS Registration Standard 

RUP Restricted Use Pesticide 

SAP Science Advisory Panel 

SCI-GROW Tier I Groundwater Computer Model 

SF 

SLC Single Layer Clothing 

SLN Special Local Need (Registrations Under Section 24(c) of FIFRA) 

TEP Typical End-Use Product 

TGAI Technical Grade Active Ingredient 

TLC Thin Layer Chromatography 

TMRC Theoretical Maximum Residue Contribution 

torr Unit of measure for atmospheric pressure 

TRR Total Radioactive Residue 

UF Uncertainty Factor 

μg/g Micrograms Per Gram 

μg/L Micrograms Per Liter 

USDA United States Department of Agriculture 

USGS United States Geological Survey 

UV Ultraviolet 

WHO World Health Organization 

WP Wettable Powder 

WPS Worker Protection Standard 

iv 
EXECUTIVE SUMMARY 

The Environmental Protection Agency (EPA or the Agency) has completed its review of the 

public comments on the revised human health and environmental risk assessments for chlorsulfuron and 

is issuing its risk management decision. The decisions outlined in this document include the 

reregistration eligibility decision for chlorsulfuron, but not the final tolerance reassessment decisions. 

Chlorsulfuron dietary and residential aggregate risks were assessed in an Agency action published in the 

Federal Register on August 14, 2002 (volume 67, number 157). This action established new 

tolerances for residues for chlorsulfuron in or on grass, forage and grass hay. This action also 

reassessed all other existing tolerances of chlorsulfuron as required by the Federal Food, Drug and 

Cosmetic Act (FFDCA), as amended by the Food Quality Protection Act (FQPA). Therefore, this 

Reregistration Eligibility Decision document and supporting risk assessments address only the 

environmental and occupational risks from the use of chlorsulfuron. For information on dietary and 

residential risks, please refer to the earlier notice published in the Federal Register. 

The Agency estimates that chlorsulfuron usage averaged approximately 72,000 pounds of 

active ingredient per year to treat over 5.5 million acres. Its largest markets in terms of total pounds 

active ingredient are winter wheat (90%) and spring wheat (5%). Data are not yet available for the 

new use on pastures and rangelands approved by EPA in 2002; however, chlorsulfuron is reportedly 

used in these areas by the US Department of Interior (Bureau of Land Management) to control invasive 

weed species. 

Risks summarized in this document are those that result only from the use of chlorsulfuron. The 

FQPA requires that the Agency consider “available information” concerning the cumulative effects of a 

particular pesticide’s residues and “other substances that have a common mechanism of toxicity.” The 

reason for consideration of other substances is due to the possibility that low-level exposures to multiple 

chemical substances that cause a common toxic effect by a common toxic mechanism could lead to the 

same adverse health effect at would a higher level of exposure to any of the substances individually. 

Unlike other pesticides for which EPA has followed a cumulative risk approach based on a common 

mechanism of toxicity, EPA has not made a common mechanism of toxicity finding for chlorsulfuron and 

any other substances and chlorsulfuron does not appear to produce a toxic metabolite produced by 

other substances. For the purposes of this action, therefore, EPA has assumed that chlorsulfuron does 

not have a common mechanism of toxicity with other substances. For information regarding EPA’s 

efforts to determine which chemicals have a common mechanism of toxicity and to evaluate the 

cumulative effects of such chemicals, see the policy statements released by EPA’s Office of Pesticide 

Programs concerning common mechanism determinations and procedures for cumulating effects from 

substances found to have a common mechanism on EPA’s website at 

http://www.epa.gov/pesticides/cumulative. 

v 
Overall Risk Summary 

The Agency’s human health risk assessment for chlorsulfuron indicates minimal risks. Both 

acute and chronic risks from food are well below the Agency’s level of concern. Dietary exposure 

from ground water or surface water sources of drinking water are also low and not of concern. There 

are no concerns about the risk to homeowners or occupational workers who handle chlorsulfuron or 

are exposed to residues after chlorsulfuron is applied. 

The ecological risk assessment for chlorsulfuron shows risk quotients (RQs) less than 0.01 for 

terrestrial and aquatic animals, which is significantly below the Agency’s level of concern. For plants, 

refined RQs range from 12 to 103 for non-target plants and from 18 to 693 for endangered plants. 

These values are significantly above the Agency’s level of concern of 1.0. 

Dietary and Aggregate Risks 

As mentioned earlier, chlorsulfuron dietary and residential aggregate risks were assessed in an 

Agency action published in the Federal Register on August 14, 2002 (volume 67, number 157). This 

assessment found that the risks from chlorsulfuron aggregate exposures (food + drinking water + 

residential) were not of concern. For all exposure scenarios, toddlers were the most highly exposed 

population subgroup. For both short-term and chronic exposure, aggregated risk from food, water and 

residential exposures account for a small portion of the risk cup. The expected concentration of 

chlorsulfuron in drinking water was 41.3 ppb for surface water and 3.5 ppb for groundwater. The 

Agency would have become concerned only if the expected concentrations in drinking water were 

greater than 1,461 ppb for short-term exposure and 161 for chronic exposure. Therefore, the risks 

from exposure to combined chlorsulfuron residues on food, in drinking water, and in a residential setting 

are not of concern. For more detailed information on dietary and residential risks, please refer to the 

earlier notice published in the Federal Register. 

Occupational Risk 

Occupational exposure to chlorsulfuron is not of concern to the Agency for handlers using 

baseline (i.e., long-sleeved shirt and long pants, shoes, socks, no respiratory protection and no 

chemical-resistant gloves) personal protective equipment. All route-specific and combined MOEs are 

greater than the target MOE of 100 and therefore risks are not of concern (MOEs range between 

1,000 and 56,000). Not all registered labels contain these personal protective equipment requirements 

at this time. 

Ecological Risk 

Ecological risks for aquatic and terrestrial animals are below the Agency’s level of concern, 

however, risks to aquatic and terrestrial plants are above the level of concern. Screening-level risk 

vi 
quotients (RQs) for non-target and endangered/threatened aquatic plants range from 12 to 21 for nontarget aquatic plants and from 18 to 31 for endangered aquatic plants. Likewise, RQs for terrestrial 

plants from the use on small grains range from 18 to 103 for non-target plants and from 122 to 1552 

for endangered/threatened plants. Direct exposure scenarios were not calculated, but RQs for plants 

and endangered plants would be significantly higher than those estimated from exposure via spray drift 

and/or runoff. 

EPA is not requiring specific label language at the present time relative to threatened and 

endangered species. The general risk mitigation required through this RED will serve to reduce the risk 

to listed species of potential concern until such time as the Agency refines its analysis. 

Regulatory Decision 

The Agency has determined that chlorsulfuron is eligible for reregistration. These products will 

be reregistered provided that the required product specific data, confidential statements of formula and 

revised labeling outlined in this document are received and accepted by EPA. Products which contain 

ingredients in addition to chlorsulfuron will be reregistered when all of their other active ingredients also 

are reregistered. Label changes are described in Section V. Appendix B identifies the generic data 

requirements that the Agency reviewed as part of its determination of reregistration eligibility of 

chlorsulfuron and lists the submitted studies that the Agency found acceptable. 

The Agency believes that specific drift language amendments proposed in this RED will 

substantially reduce, though may not completely eliminate, the risks to non-target plants. The Agency 

intends to conduct an additional assessment of chlorsulfuron, and may consider other similar herbicides, 

at a later date. Reviewing these pesticides as a possible group will allow the Agency to assess the risks 

from all of these pesticides simultaneously, rather than individually on a case-by-case basis. A 

cohesive, comprehensive decision to protect non-target plants (including endangered and threatened 

species) can then be implemented more consistently for all pesticides in the group. The Agency intends 

to initiate this review after August 3, 2006. 

The Agency is issuing this RED document for chlorsulfuron as announced in a Notice of 

Availability published in the Federal Register. This RED includes guidance and time frames for making 

any necessary label changes for products containing chlorsulfuron. 

Summary of Mitigation Measures 

EPA believes that chlorsulfuron is eligible for reregistration provided the following actions are 

implemented, combined with the general mitigation measures previously described: 

vii 
Dietary, Residential, and Aggregate Risks: 

• No label changes are necessary 

• Confirmatory data are required, including a two-generation reproduction study, as discussed in 

the 2002 notice published in the Federal Register and required by this RED 

Occupational Risks 

• Baseline PPE must be specified on the labels for all chlorsulfuron products. Additional PPE 

may be required on a product-specific basis. 

Ecological Risks 

• Label amendments to minimize the potential for spray drift. 

• Confirmatory data are required to determine possible reproductive toxicity of chlorsulfuron to 

plants exposed to small droplets of chlorsulfuron through drift. These data are important to 

refine the risk to plant reproduction, which may be more sensitive than seedling emergence or 

vegetative vigor. 

viii 
I. Introduction 

The Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) was amended in 1988 to 

accelerate the reregistration of products with active ingredients registered prior to November 1, 1984. 

The amended Act calls for the development and submission of data to support the reregistration of an 

active ingredient, as well as a review of all submitted data by the U.S. Environmental Protection 

Agency, henceforth referred to as EPA or “the Agency.” Reregistration involves a thorough review of 

the scientific database underlying a pesticide’s registration. The purpose of the Agency’s review is to 

reassess the potential hazards arising from the currently registered uses of the pesticide; to determine 

the need for additional data on health and environmental effects; and to determine whether the pesticide 

meets the “no unreasonable adverse effects” criteria of FIFRA. 

On August 3, 1996, the Food Quality Protection Act of 1996 (FQPA) was signed into law. 

This Act amends FIFRA to require reassessment of all existing tolerances for pesticides in food and 

also requires that EPA review all tolerances in effect on August 2, 1996, the day before the enactment 

of the FQPA, by August 3, 2006. The Agency has decided that, for those chemicals that have 

tolerances and are undergoing reregistration, the tolerance reassessment will be initiated through this 

reregistration process. FQPA also requires that, when considering whether to establish, modify, or 

revoke a tolerance, the Agency consider "available information" concerning the cumulative effects of a 

particular pesticide's residues and "other substances that have a common mechanism of toxicity." 

Risks summarized in this document are those that result only from the use of chlorsulfuron. The 

FQPA requires that the Agency consider available information concerning the cumulative effects of a 

particular pesticide’s residues and other substances that have a common mechanism of toxicity. The 

reason for consideration of other substances is due to the possibility that low-level exposures to multiple 

chemical substances that cause a common toxic effect by a common toxic mechanism could lead to the 

same adverse health effect that would occur at a higher level of exposure to any of the substances 

individually. Unlike other pesticides for which EPA has followed a cumulative risk approach based on 

a common mechanism of toxicity, EPA has not made a common mechanism of toxicity finding for 

chlorsulfuron and any other substances and chlorsulfuron does not appear to produce a toxic metabolite 

produced by other substances. For the purposes of this action, therefore, EPA has assumed that 

chlorsulfuron does not have a common mechanism of toxicity with other substances. For information 

regarding EPA’s efforts to determine which chemicals have a common mechanism of toxicity and to 

evaluate the cumulative effects of such chemicals, see the policy statements released by EPA’s Office of 

Pesticide Programs concerning common mechanism determinations and procedures for cumulating 

effects from substances found to have a common mechanism on EPA’s website at 

http://www.epa.gov/pesticides/cumulative. 

This document presents the Agency's decision regarding the reregistration eligibility of the 

registered uses of chlorsulfuron. The decisions outlined in this document include the reregistration 

eligibility decision, but not the tolerance reassessment decisions. Chlorsulfuron dietary and residential 

1
aggregate risks were assessed in an Agency action published in the Federal Register on August 14, 

2002 (volume 67, number 157). This action established new tolerances for residues for chlorsulfuron in 

or on grass, forage and grass hay. This action also reassessed all other existing tolerances of 

chlorsulfuron as required by the Federal Food, Drug and Cosmetic Act (FFDCA), as amended by the 

FQPA. Therefore, this Reregistration Eligibility Decision (RED) document and the supporting risk 

assessments address only the environmental and occupational risks from the use of chlorsulfuron. For 

information on dietary and residential risks and the tolerance reassessments, please refer to the earlier 

notice published in the Federal Register. 

In an effort to simplify the RED document, the information presented herein is summarized from 

more detailed information, which can be found in the technical supporting documents for chlorsulfuron 

referenced in this RED document. The revised risk assessments and related addenda are not included 

in this document, but are available on the Agency's web page at www.epa.gov/pesticides, and in the 

Public Docket at http://www.epa.gov/edocket under docket #OPP-2004-0219. 

This document presents the Agency’s revised occupational and ecological risk assessments and 

the reregistration eligibility decision for chlorsulfuron. This document consists of six sections. Section I 

contains the regulatory framework for reregistration/tolerance reassessment. Section II provides a 

profile of the use and usage of the chemical. Section III gives an overview of the revised human health 

and environmental effects risk assessments resulting from public comments and other information. 

Section IV presents the Agency's decision on reregistration eligibility and risk management for 

chlorsulfuron. Section V summarizes the label changes necessary to implement the risk mitigation 

measures outlined in Section IV. Section VI provides information on how to access related documents. 

Finally, the Appendices list references and contain other information, such as the Data Call-Ins (DCIs) 

to be issued with this RED. The preliminary and revised risk assessments for chlorsulfuron are available 

in the Public Docket at http://www.epa.gov/edocket under docket #OPP-2004-0219. 

II. Chemical Overview 

A. Regulatory History 

Chlorsulfuron was first registered in the United States in 1982 by E.I. du Pont de Nemours and 

Company. It was formulated into products for use on food crops (wheat, barley, and forage grasses) 

and non-food crops (non-cropland grasses and tree plantings). Since 1988 additional products have 

been registered, mostly by DuPont. Nufarm Americas Inc. has one registered product containing 

chlorsulfuron (EPA Reg. # 228-375) and Lesco Inc has one registered product containing chlorsulfuron 

(EPA Reg. # 10404-59). In addition there are two products registered as Special Local Needs (SLN) 

registrations for use in Oklahoma and Texas to allow aerial application to wheat. 

2
B. Chemical Identification 

Chlorsulfuron: 

Common Name: 

Chlorsulfuron 

Chemical Name: 2-chloro-N-[[(4-methoxy-6-methyl-1,3,5-triazin-2-

yl)amino]carbonyl]benzenesulfonamide 

Chemical family: Sulfonylurea 

Case number: 0631 

CAS registry numbers: 64902-72-3 

OPP chemical code: 118601 

Empirical formula: C12H12ClN5O4S 

Molecular weight: 357.7709 

Trade and other names: Glean®, Finesse®, Telar® 

Basic manufacturer: E.I. du Pont de Nemours and Company 

Technical grade chlorsulfuron has a melting point of 174-178° C, octanol/water partition 

coefficient of 1.11, and vapor pressure of 4.6 x 10-6 mmHg at 25° C. Chlorsulfuron is soluble in water 

(125 ppm at 25° C). 

3
C. Use Profile 

The following information is based on the currently registered uses of chlorsulfuron: 

Type of Pesticide: Herbicide 

Mode of Herbicidal Action: Inhibits the activity of acetolactate synthase, which is an enzyme 

required for plant cell growth. 

Summary of Use Sites: 

Food and/or feed crops 

• Cereal Grains 

• Pasture and Rangelands 

Non-food and outdoor residential 

• Industrial sites 

• Rights-of-way 

• Turf grass 

Public Health Uses: None 

Target Pests: alta fescue (Kentucky 31), annual ryegrass, annual sowthistle, aster, bahiagrass, 

bedstraw, Bermudagrass, big bluestems, black mustard, blue grama, blue mustard, bluegrass, 

bluestem, bouncingbet, broadleaf plantain, broadleaf weeds, bromegrass, buffalograss, bull 

thistle, bur beakchervil, burclover, buttercup, Canada thistle, chickweed, coast fiddleneck, 

common chickweed, common cinquefoil, common groundsel, common lambsquarters, common 

mallow, common mullein, common purslane, common ragweed, common speedwell, common 

sunflower, common tansy, common yarrow, conical catchfly, corn gromwell, corn spurry, cow 

cockle, crested wheatgrass, curly dock, cutleaf eveningprimrose, dandelion, downy brome, 

dyers woad, false chamomile, falseflax, fescue, fiddleneck, field pennycress, filaree, flixweed, 

foxtail, goldenrod, groundsel, hempnettle, henbit, hoary cress, horsetail, indiangrass, jim hill 

mustard, kochia, ladysthumb, lambsquarters, london rocket, lovegrass, marestail, mayweed, 

minerslettuce, mouseear chickweed, musk thistle, needlegrass, orchardgrass, pennsylvania 

smartweed, perennial grasses, perennial pepperweed, perennial ryegrass, pineappleweed, 

poison hemlock, prickly lettuce, prostrate knotweed, prostrate pigweed, puncturevine, 

purslane, ragweed, red clover, redroot pigweed, redstem filaree, russian knapweed, russian 

thistle, ryegrass, sand bluestem, scotch thistle, scouringrush, setaria, shepherdspurse, sideoats 

grama, smooth brome, smooth pigweed, smutgrass, speedwell, sunflower, sweetclover, 

4
switchgrass, tall fescue, tansymustard, tarweed, teasel, treacle mustard, tumble mustard, turkey 

mullein, velvetgrass, Virginia buttonweed, waterpod, western wheatgrass, wheatgrass, white 

clover, white cockle, whitetop, wild buckwheat, wild carrot, wild garlic, wild mustard, wild 

onion, wild parsnip, wild radish, wild turnip, wild violet, yellow rocket, yellow starthistle 

Formulation Types Registered: Water-dispersible granules 

Method and Rates of Application: 

Equipment - Aircraft; boom sprayer; hand-held sprayer; handgun; low volume ground 

sprayer; sprayer 

Method - Broadcast; low volume spray (concentrate); soil treatment; spot treatment; 

spray 

Timing - Early postemergence; fallow; postemergence; postplant; preemergence; 

preplant; when needed 

Use Classification: General use 

A. Estimated Usage of Pesticide 

This section summarizes the best estimates available for many of the pesticide uses of 

chlorsulfuron, based on available pesticide usage information. This information was used in the risk 

assessments for chlorsulfuron. Additional details are available in the “Quantitative Use Assessment” 

document, which is available in the public docket and on the Internet. The data, reported on an 

aggregate and site (crop) basis, reflect annual fluctuations in use patterns as well as the variability in 

using data from various information sources. 

The Agency estimates that chlorsulfuron usage averaged approximately 72,000 pounds of 

active ingredient per year to treat over 5.5 million acres. Its largest markets in terms of total pounds 

active ingredient are winter wheat (90%) and spring wheat (5%). The remaining usage is primarily on 

barley, oats, fallow fields and pasture/hay. Crops with a high percentage of the total U.S. planted acres 

treated include winter wheat (11%) and oats (2%), while registered sites with little or no usage include 

lawn and ornamental turf. Most chlorsulfuron usage is in California, Idaho, Kansas, Minnesota, North 

Dakota, Oklahoma, Oregon, South Dakota, Texas, and Washington. Data are not yet available for the 

new use on pastures and rangelands approved by EPA in 2002; however, chlorsulfuron is reportedly 

used in these areas by the US Department of Interior (Bureau of Land Management) to control invasive 

weed species. 

5
Although chlorsulfuron is registered for residential use, this is very minor compared to the 

agricultural uses. Chlorsulfuron is used by homeowners as a spot treatment on lawns; however, usage 

data show little or no usage on lawns. 

Table 1. Chlorsulfuron Estimated Usage 

Crop 

Average Pounds 

Active Ingredient 

Applied 

Percent Crop Treated

 Average Maximum 

Barley 1,000 1% 4% 

Oats 1,000 2% 4% 

Pasture and Hay, Other 1,000 0% < 1% 

Wheat, Spring 4,000 1% 3% 

Wheat, Winter 65,000 11% 17% 

Lawns and Ornamental Turf < 1,000 - -

III. Summary of Chlorsulfuron Risk Assessment 

The purpose of this summary is to assist the reader by identifying the key features and findings 

of these risk assessments, and to help the reader better understand the conclusions reached in the 

assessments. Human health and ecological risk assessment documents and supporting information were 

used to formulate the safety finding and regulatory decision for the herbicide chlorsulfuron. These 

documents may be found in the Public Docket at http://www.epa.gov/edocket under docket #OPP2004-0219. 

Chlorsulfuron dietary and residential aggregate risks were assessed in an Agency action 

published in the Federal Register on August 14, 2002 (volume 67, number 157). This 

assessment found that the risks from chlorsulfuron aggregate exposures (food + drinking water + 

residential) were not of concern. For all exposure scenarios, toddlers were the most highly exposed 

population subgroup. For both short-term and chronic exposure, aggregated risk from food, drinking 

water and residential exposures account for a small portion of the risk cup. The expected 

concentration of chlorsulfuron in drinking water was 41.3 ppb for surface water and 3.5 ppb for 

groundwater. The Agency would have become concerned only if the expected concentration in 

drinking water were greater than 1,461 ppb for short-term exposure and 161 ppb for chronic 

exposure. Therefore, the risks from exposure to combined chlorsulfuron residues on food, in drinking 

water, and in a residential setting are not of concern. 

This action established new tolerances for residues for chlorsulfuron in or on grass, forage and 

grass hay. This action also reassessed all other existing tolerances of chlorsulfuron as required by the 

Federal Food, Drug and Cosmetic Act (FFDCA), as amended by the Food Quality Protection Act 

6
(FQPA). The August 14, 2002, Federal Register notice contains a detailed discussion of the dietary, 

residential and aggregate risks from chlorsulfuron. Therefore, this Reregistration Eligibility Decision 

document and the supporting risk assessments address only the environmental and occupational risks 

from the use of chlorsulfuron. For more detailed information on dietary and residential risks, please 

refer to the earlier notice published in the Federal Register. 

As part of the public participation process for the RED, EPA released its preliminary 

environmental and occupational risk assessments for chlorsulfuron for public comment on September 

24, 2004 (Phase 3 of the public participation process). In response to comments received and new 

studies submitted during Phase 3, the ecological risk assessment was updated and refined. The 

occupational risk assessment remained unchanged. 

A. Human Health Risk Assessment 

As outlined in the 2002 Federal Register notice for chlorsulfuron, EPA has reviewed all 

toxicity studies submitted to the Agency and has determined that the toxicity database is sufficient to 

support this reregistration eligibility decision for all currently registered uses. For specific details on the 

toxicological endpoints to assess dietary and residential exposure, FQPA Safety Factor, dietary, 

residential and aggregate risk assessments and tolerance reassessments, please see the notice published 

in the Federal Register on August 14, 2002 (volume 67, number 157). 

1. Occupational Exposure and Risk 

A summary of the Agency’s occupational risk assessment is presented below. For detailed 

discussions of all aspects of the occupational risk assessment, see the technical support documents 

listed in Appendix C. Documents are available in the docket OPP-2004-0219 and on the internet at 

http://www.epa.gov/edockets. 

Occupational workers can be exposed to a pesticide through mixing, loading, applying a 

pesticide, or re-entering treated sites. For chlorsulfuron, occupational handlers of chlorsulfuron include 

individual farmers or growers who mix, load, and/or apply pesticides, as well as professional or custom 

agricultural applicators. 

Risk to occupational handlers is estimated using a margin of exposure (MOE), which is the ratio 

of the No Observed Adverse Effect Level (NOAEL) from an animal study with exposure. For 

chlorsulfuron, MOEs greater than 100 for occupational handlers are not of concern to the Agency. 

Based on the use pattern and site information for chlorsulfuron, exposure no longer than short-term 

exposure (1-28 days) is expected. Hence, intermediate-term (1 to 6 months) and long-term (greater 

than 6 months) occupational handler risks were not assessed. Because chlorsulfuron data show no 

evidence of carcinogenicity, no cancer risk assessment was conducted. 

7
a. Toxicity 

The toxicological endpoints used in assessing the risks from occupational exposures to 

chlorsulfuron are listed in Table 2. The assessment uses the NOAEL of 75 mg/kg/day from the rabbit 

developmental toxicity study as the endpoint for short-term dermal and inhalation exposure. Since no 

dermal or inhalation absorption data are available for chlorsulfuron, toxicity by the dermal and inhalation 

routes are considered to be equivalent to toxicity by the oral route of exposure (i.e., dermal absorption 

factor is assumed to be 100%). 

Table 2. Summary of Toxicological Endpoint Used in the Human Occupational Risk 

Assessment for Chlorsulfuron 

Assessment Effect Level Endpoint Study Absorption factor, % oral 

absorption

 Short-term 

dermal 

NOAEL = 75 

mg/kg/day 

Maternal toxicity, based 

on decreased body 

Rabbit 

Developmental 

100 

Short-term 

inhalation 

(LOAEL = 200 

mg/kg/day) 

weight/ body-weight gain 

in females 

Toxicity Study 

(MRID 41983101) 100 

The acute toxicity profile for chlorsulfuron is summarized in Table 3. Chlorsulfuron is not 

acutely toxic via the oral and inhalation [Toxicity Category IV] routes of exposure and via the dermal 

[Toxicity Category III] route of exposure. Adequate data are not available for an assessment of eye or 

skin irritation potential or for dermal sensitization potential. 

Table 3. Acute Toxicity Profile for Chlorsulfuron 

Guideline MRID Study Type Results Toxicity 

Category 

81-1 00031406 Acute Oral LD50 = 5.5/6.3 g/kg

 (males and females) IV 

81-2 00083956 Acute Dermal LD50 = 3400 mg/kg III 

81-3 00086825 Acute Inhalation LC50 = 5.9 m/L IV 

81-4 00126597 Primary Eye Irritation1 Not an eye irritant IV 

81-4 45833702 Primary Eye Irritation2 Not an eye irritant IV 

81-5 45833704 Primary Skin Irritation2 Not a skin irritant IV 

81-6 Dermal Sensitization No adequate study N/A 

1 MRID 00126597 is classified as unacceptable/nonguideline. 

2 MRIDs 45833702 and 45833704 have not yet been formally reviewed. Results are preliminary and will be 

confirmed before end-use products are reregistered. 

N/A Not available 

8 
b. Occupational Exposure 

Agricultural Handler Exposure. EPA assessed occupational exposure to chlorsulfuron using 

the Pesticide Handlers Exposure Database (PHED). There were no chemical-specific data available to 

assess potential exposure to workers for chlorsulfuron. EPA also used standard assumptions about 

average body weight, work day, and daily areas treated. For adult handlers using chlorsulfuron, an 

average adult body weight of 70 kg was used for all exposure scenarios because all scenarios are 

occupational and the toxic effect was seen in both males and females. EPA derived information about 

use patterns, application methods, and the range of application rates used in the exposure assessment 

from the current chlorsulfuron labels. The application rates specified on the chlorsulfuron labels range 

from 0.0625 to 0.14 lbs a.i./A in agricultural settings. The Agency typically uses acres treated per day 

values that are thought to represent eight hours of application work for specific types of application 

equipment. 

Occupational handler exposure assessments are conducted by the Agency using different levels 

of personal protection. The Agency typically evaluates all exposures with minimal protection and then 

adds additional protective measures using a tiered approach until the MOEs are no longer of concern, 

going from minimal to maximum levels of protection. The lowest suite of personal protective equipment 

(PPE) is baseline (long sleeve shirt, long pants, shoes and socks). If MOEs are of concern (less than 

100) at baseline, increasing levels of PPE are applied. If MOEs are still less than 100, engineering 

controls are applied. For chlorsulfuron, EPA only conducted an assessment using baseline PPE. 

Based on currently registered uses, the Agency identified the following major occupational 

exposure scenarios for chlorsulfuron: 

Scenario 1: Mixing and loading dry flowable for aerial application (wheat, high acreage) 

Scenario 2: Mixing and loading dry flowable for aerial application (cereal grains, low acreage) 

Scenario 3: Mixing and loading dry flowable for groundboom application (cereal grains) 

Scenario 4: Mixing and loading dry flowable for groundboom application (grass areas) 

Scenario 5: Mixing and loading dry flowable for high-pressure handwand (grass areas) 

Scenario 6: Applying sprays using aircraft (wheat) 

Scenario 7: Applying sprays using aircraft (cereal grains) 

Scenario 8: Applying sprays using groundboom (wheat) 

Scenario 9: Applying sprays using groundboom (cereal grain) 

Scenario 10: Applying sprays using high-pressure handwand (cereal grains) 

Scenario 11: Flagger for aerial application (cereal grains) 

Chlorsulfuron labels contain a variety of PPE, depending on the toxicity of the end-use product 

and the risk to users from any additional active ingredients. Some labels do not specify PPE, while 

other labels minimally require the PPE of long-sleeved shirt, long pants, shoes, socks, and gloves. This 

RED will address PPE needed solely based on the risk of the active ingredient chlorsulfuron. 

9
c. Occupational Handler Risk Summary 

As previously mentioned, EPA assessed exposure and risk for eleven scenarios. For 

chlorsulfuron, an MOE greater than 100 does not exceed the Agency’s level of concern for effects 

from short-term exposure. Based on the use pattern and site information for chlorsulfuron, exposure no 

longer than short-term exposure (1-28 days) is expected. Hence, intermediate-term (1 to 6 months) 

and long-term (greater than 6 months) occupational handler risks were not assessed. EPA did not 

evaluate cancer risk to agricultural handlers because no chlorsulfuron data showed evidence of 

carcinogenicity. 

At the baseline level of protection (i.e., long-sleeved shirt and long pants, shoes, socks, no 

respiratory protection and no chemical-resistant gloves) all route-specific and combined MOEs are 

greater than the target MOE of 100 and therefore risks are not of concern (MOEs range between 

1,000 and 56,000). Therefore, risks are below EPA’s level of concern and no additional levels of 

protection were considered in the risk assessment. Not all registered labels contain these personal 

protective equipment requirements at this time. 

Risks for agricultural handlers are summarized in Table 4 when handlers are wearing baseline 

attire (long sleeve shirt, long pants, shoes, and socks). 

Table 4. Summary of Chlorsulfuron Occupational Handler Risk: Baseline Clothing1 

Exposure Scenario 

Application 

Rate 

(lbs a.i./Acre) 

Area Treated2 

(Acres/Day) 

Combined (Dermal and Inhalation) 

Short-Term Margin of Exposure (MOE) 3 

Mixer/Loader 

(1) Aerial - wheat 

0.0625 

1200 1000 

(2) Aerial - grain 350 3600 

(3) Broadcast - grain 200 6300 

(4) Broadcast - grasses 

0.14 

80 7000 

(5) High-pressure handwand 

(100 gallons) 10 56,000 

Applicator 

(6) Aerial - wheat 

0.0625 

1200 14000 

(7) Aerial - grain 350 47000 

(8) Broadcast - wheat 200 28000 

(9) Broadcast - grain 0.14 80 32000 

10 
Exposure Scenario 

Application 

Rate 

(lbs a.i./Acre) 

Area Treated2 

(Acres/Day) 

Combined (Dermal and Inhalation) 

Short-Term Margin of Exposure (MOE) 3 

(10) High-pressure handwand 

(100 gallons) 0.14 10 2000 

(11) Flagging aerial spray ­

grain applications 0.0625 350 21,000 

1 Baseline clothing includes long-sleeved shirt, long pants, socks and shoes. 2 Amounts of acreage treated per day are maximum values from the HED Science Advisory Council for 

Exposure Policy #009 " Standard Values for Daily Acres Treated in Agriculture,” dated July 5, 2000. 3 MOE (unitless) = NOAEL (mg/kg/day) ÷ Combined Absorbed Daily Dose (mg/kg/day), where a NOAEL of 

75 mg/kg/day is used for short-term and dermal and inhalation exposures. 

d. Post-Application Exposure and Risk 

Because chlorsulfuron is used early in the season on crops/areas that have little worker activity, 

no post-application exposure is expected. Therefore, no post-application risks have been assessed. 

Based on a preliminary evaluation of the eye and skin irritation studies, the Agency believes that 

a 12-hour Restricted Entry Interval (REI) would be sufficiently protective for chlorsulfuron. These data 

will be formally reviewed to confirm the toxicity category. 

Chlorsulfuron also continues to be a candidate for a 4-hour REI. PR Notice 95-3 provides 

instructions and criteria for evaluating an end-use product to determine whether the 12-hour REI may 

be reduced to 4 hours. End-use products that currently contain a 4-hour REI may remain unchanged. 

2. Incident Reports 

Very few poisoning incidents related to the use of chlorsulfuron were reported in any of the 

data sources available to the Agency. Over nine years, only two incidents have been reported to the 

Poison Centers. Therefore, the Agency believes that the incident information for chlorsulfuron is 

insufficient to support any change in chlorsulfuron’s use directions or Personal Protective Equipment. 

B. Environmental Risk Assessment 

A summary of the Agency’s environmental risk assessment is presented below. For detailed 

discussions of all aspects of the environmental risk assessment, see the technical support documents 

listed in Appendix C. Documents are available in the docket OPP-2004-0219 and on the internet at 

http://www.epa.gov/edockets. 

Based on public comment and new data, revisions have been made to the environmental risk 

assessment since the preliminary risk assessment was completed. The Agency has considered and 

11
incorporated several of these comments, leading to a more refined risk assessment. Changes include 

recalculation of risk quotients for terrestrial plants based on the review of recent greenhouse studies that 

are more consistent with Agency guidelines than the previous studies, and the inclusion of terrestrial 

plant toxicity endpoints to better characterize the risk due to chlorsulfuron. However, the basic 

conclusions of the preliminary risk assessment of chlorsulfuron have not changed. Thus, adverse effects 

in nontarget aquatic and terrestrial plants are possible from the current labeled uses of chlorsulfuron 

modeled in this evaluation. 

1. Environmental Fate and Transport 

Chlorsulfuron is likely to be persistent and highly mobile in the environment. It may be 

transported to nontarget areas by runoff and/or spray drift. Degradation by hydrolysis appears to be 

the most significant mechanism for degradation of chlorsulfuron, but is only significant in acidic 

environments (23 day half-life at pH = 5); it is stable to hydrolysis at neutral to high pH. Degradation 

half-lives in soil environments range from 14 to 320 days. Additional information on the environmental 

fate of chlorsulfuron can be found in the supporting documents referenced in Appendix C. 

2. Ecological Risk Assessment 

The Agency’s ecological risk assessment compares toxicity endpoints from ecological toxicity 

studies to estimated environmental concentrations (EECs) based on environmental fate characteristics 

and pesticide use data. To evaluate the potential risk to nontarget organisms from the use of 

chlorsulfuron products, the Agency calculates a Risk Quotient (RQ), which is the ratio of the EEC to 

the toxicity endpoint values, such as the median lethal dose (LD50) or the median lethal concentration 

(LC50). These RQ values are then compared to the Agency's levels of concern (LOCs), which 

indicates whether a chemical, when used as directed, has the potential to cause undesirable effects on 

nontarget organisms. In general, the higher the RQ the greater the concern. When the RQ exceeds the 

LOC for a particular category, the Agency presumes a risk of concern to that category. The LOCs 

and the corresponding risk presumptions are presented in Table 5 below. 

Table 5. EPA’s Levels of Concern (LOCs) and Associated Risk Presumptions 

RQ Value Resulting Presumption 

Mammals and Birds 

Acute RQ > LOC of 0.5 Acute risk 

Acute RQ >LOC of 0.2 Risk that may be mitigated through restricted use 

Acute RQ > LOC of 0.1 Acute effects may occur in endangered species 

Chronic RQ > LOC of 1 Chronic risk to all species 

Fish and Aquatic Invertebrates 

Acute RQ > LOC of 0.5 Acute risk 

12 
RQ Value Resulting Presumption 

Acute RQ > LOC of 0.1 Risk that may be mitigated through restricted use 

Acute RQ >LOC of 0.05 Acute effects may occur in endangered species 

Chronic RQ > LOC of 1 Chronic risks to all species

 Plants 

The RQ > LOC of 1 Acute risk and endangered plants may be affected 

a. Ecological Hazard Profile 

Numerous ecological toxicity studies were conducted to support the reregistration of 

chlorsulfuron. Toxicity testing reported in this section does not represent all species of birds, mammals, 

or aquatic organisms. A few surrogate species are considered representative of all freshwater fish 

(2000+) and bird (680+) species in the United States. For mammals, acute studies are usually limited 

to Norway rat or the house mouse. Estuarine/marine testing is usually limited to a crustacean, a 

mollusk, and a fish. Also, neither reptiles nor amphibians are tested. The assessment of risk or hazard 

makes the assumption that avian and reptilian toxicities are similar. The same assumption is used for 

fish and amphibians. The results of these studies are summarized herein; for specific details, please see 

the documents referenced in Appendix C which also contain detailed discussion of toxicity studies for 

chlorsulfuron that have been published in public literature. 

Toxicity to Aquatic Animals 

Chlorsulfuron is practically nontoxic to both freshwater and estuarine/marine fish on an acute 

exposure basis and is slightly toxic to estuarine/marine invertebrates. Chronic exposure of rainbow 

trout (Oncorhynchus mykiss) to chlorsulfuron resulted in a No Observed Effect Concentration 

(NOEC) of 32 mg/L while a chronic study of waterfleas (Daphnia magna) resulted in a NOEC of 20 

mg/L. Table 6 summarizes the most sensitive endpoints used in the risk assessment of aquatic animals. 

Table 6. Summary of acute and chronic aquatic toxicity data for chlorsulfuron. 

Species 

Acute Toxicity Chronic Toxicity 

96-hr LC50 

(mg/L) 

48-hr EC50 

(mg/L) 

Acute Toxicity 

(MRID) 

NOEC 

(mg/L) 

Data Citation 

(MRID) 

Rainbow trout Practically 

Oncorhynchus mykiss >250 NA Nontoxic 32 41976405 

(formulated product) (41976405) 

Water flea 

Daphnia magna NA >370 

Practically 

Nontoxic 

(00035262) 

20 41976408 

13 
1 

Species 

Acute Toxicity Chronic Toxicity 

96-hr LC50 

(mg/L) 

48-hr EC50 

(mg/L) 

Acute Toxicity 

(MRID) 

NOEC 

(mg/L) 

Data Citation 

(MRID) 

Sheepshead minnow Practically 

Cyprinodon >980 NA Nontoxic NA NA 

variegatus (41976401) 

Mysid shrimp 

Mysidopsis bahia 89 NA Slightly Toxic (41976402) NA NA 

NA = Not Available 

Toxicity to Aquatic Plants 

Aquatic plant toxicity ranged from practically nontoxic to very highly toxic. Duckweed (Lemna 

gibba) was the most sensitive vascular aquatic plant, with an EC50 of 3.5 x 10-4 mg ai/L and a NOEC 

of 2.4 x 10-4 mg/L. The most sensitive nonvascular aquatic plant is green algae with an EC50 of 5.5x10-

5

 mg/L and an NOEC of 9.5x10-6 mg/L. 

Table 8. Summary of Chlorsulfuron Aquatic Plant Growth Toxicity Tests

 Species Toxicity Value Citation/MRID Author 

(Year) 

Study 

Classification 

Pseudokirchneriella 

subcapitata 

EC50 = 0.000055 mg/L 

NOEC = 0.0000095 mg/L 

42186801 

Blasburg, J. et al. (1991) Supplemental1 

Skeletonema 

costatum 

NOEC =126 mg/L 

EC50 >126 mg/L 

45832902 

R.L.Boeri et al. (2001) Core 

Navicula pelliculosa NOEC =126 mg/L 

EC50 >126 mg/L 

45832904 

R.L.Boeri et al. (2001) Core 

Anabaena flos-aquae NOEC = 0.236 mg/L 

EC50 = 0.609 mg/L 

45832903 

R.L.Boeri et al. (2001) Core 

Lemna gibba NOEC = 0.00024 mg/L 

EC50 = 0.00035 mg/L 

45832901 

R.L.Boeri et al. (2001) Supplemental1 

Studies conducted under static conditions. Concentrations should be renewed 3 - 4 times in 14-day test. 

Because of guideline deviations, some studies are classified as supplemental and do not fulfill 

data requirements for plant toxicity testing. However, these studies were determined to be scientifically 

sound and are suitable for use in the screening-level risk assessment for non-target and endangered 

plants. 

14
Toxicity to Terrestrial Animals 

Chlorsulfuron is practically non-toxic to birds and mammals on an acute exposure basis and is 

also practically nontoxic to birds on a subacute dietary exposure basis. Following chronic exposure, 

bobwhite quail exhibited significant reductions in female body weight, 14-day old survivors/normal 

hatchlings, viable embryos/eggs set, and 14-day hatchling survival/eggs set. Chlorsulfuron is also 

practically nontoxic to honeybees on an acute contact basis. Table 9 provides a summary of the most 

sensitive ecological toxicity endpoints used in the hazard assessment of terrestrial animals for 

chlorsulfuron. 

Table 9. Summary of Acute and Chronic Toxicity for Terrestrial Animals 

Species 

Acute Toxicity Chronic Toxicity 

LD50 1 Acute Oral 

Toxicity 

5-day 

LC50 1 

(ppm) 

Subacute 

Dietary 

Toxicity 

NOEC/LOEC 

(ppm) 

Affected 

Endpoints 

Northern bobwhite 

quail NA NA NA NA 174 / 961 reproduction 

Colinus virginianus 

Mallard duck 

Anas platyrhynchos NA NA >5,000 practically non-toxic NA NA 

Honey bee 

Apis meliferus

 25 

μg/bee NA NA NA NA NA 

Laboratory rat 

Rattus norvegicus 

5,500 

ppm 

practically 

non-toxic NA NA NA NA 

1 LD50 is the dosage that causes lethality to 50% of the test animals 

2 LC50 is the concentration that causes lethality to 50% of the test animals 

NA Not available 

Toxicity to Terrestrial Plants 

Laboratory-derived toxicity values for terrestrial and aquatic plants are summarized Table 10. 

Chlorsulfuron is toxic to nontarget terrestrial plants with EC25 values as low as 1.0 x 10-5 lbs a.i./A and 

an NOEC value of 5.4 x 10-6 lbs a.i. /A (vegetative vigor). Based on available data, the slope of the 

dose-response curve for chlorsulfuron varies between species, suggesting a range of expected 

sensitivities. 

Chlorsulfuron exposure may cause visible symptoms in days or weeks and may effect plant 

reproduction (fruit or seed production) with limited visible symptoms. Plants that have absorbed 

sufficient chlorsulfuron on their foliage, in the short term, may show initial symptoms of spotting, and leaf 

15
puckering or twisting (Felsot et al 1996). Exposed plants also may show chlorosis and discolored 

veins. 

Chlorsulfuron symptoms may become more pronounced and lead to plant death or the plant 

may outgrow the symptoms in 1 to 2 months depending on the sensitivity of the plant and the magnitude 

of the exposure. Developmental/reproductive effects of chlorsulfuron exposure may not be apparent 

for three or more months after exposure. Reduced seed and fruit development resulting from 

chlorsulfuron exposure has been documented in canola, smartweed, soybean, and sunflower (Fletcher 

et al 1996). Because reproductive effects may occur in the absence of other more immediate 

symptoms of herbicide exposure, it is expected to be difficult to recognize chlorsulfuron toxicity in the 

field. The studies listed in Table 10, which serve as the basis for the risk assessment, measured lethality 

as the effect. 

Table 10. Summary of Chlorsulfuron Toxicity Testing for Terrestrial Plants (based on 

most sensitive endpoints from MRIDs 46361801 and 46326801) 

Seedling Emergence Vegetative Vigor 

Plant Type Crop 

(Shoot dry weight) 

Crop 

(Shoot dry weight) 

NOEC EC25 NOEC EC25 

(lbs ai/A) (lbs ai/A) (lbs ai/A) (lbs ai/A) 

Dicot pea 1.8 x 10-4 2.2 x 10-4 sugar beet 5.4 x 10-6 1.0 x 10-5 

Monocot onion 4.6 x 10-5 

(shoot length) 3.1 x 10-4 onion 5.4 x 10-6 2.2 x 10-5 

b. Environmental Exposure to Non-Target Organisms 

Exposure to Aquatic Organisms 

Surface water concentrations resulting from chlorsulfuron application to wheat and turf were 

based on a screening-level model assessment. Four scenarios were simulated: North Dakota wheat, 

Texas wheat, Pennsylvania turf and Florida turf. The assessment estimates application timing from the 

product labels and uses a range of application dates. Detailed descriptions and model inputs can be 

found in the supporting documents listed in Appendix C. 

Because of its persistence, chlorsulfuron concentrations did not diminish over the simulation 

period, causing chronic and peak concentrations to be nearly the same for all scenarios tested. Table 

11 presents the peak and average concentrations of chlorsulfuron that the model predicts for a 

simulated farm pond. 

16
1 

1 

Table 11. Summary of Modeled Ecological Concentrations of Chlorsulfuron1 

Scenario Formulation and 

Application 

peak 

(ppb) 

96 hr 

(ppb) 

21-day 

(ppb) 

60-day 

(ppb) 

90-day 

(ppb) 

yearly 

(ppb) 

ND wheat Glean® @ 0.023 lb/A 4.2 4.2 4.2 4.2 4.2 4.2 

TX wheat Glean® @ 0.023 lb/A 6.3 6.3 6.3 6.3 6.3 6.3 

PA turf Telar® @ 0.0625 lb/A 5.9 5.9 5.9 5.9 5.9 5.8 

FL turf Telar® @ 0.0625 lb/A 9.5 9.5 9.5 9.5 9.5 9.5 

Based on one application per season at maximum labeled rate applied aerially 

Exposure to Terrestrial Organisms 

Exposure to Animals 

The Agency assessed exposure to terrestrial organisms by first predicting the amount of 

chlorsulfuron residues found on animal food items and then by determining the amount of pesticide 

consumed by using information on typical food consumption by various species of birds and mammals. 

The amount of residues on animal feed items are based on the Fletcher nomogram (a model developed 

by Fletcher, Hoeger, Kenaga, et al.). EPA modeled the maximum and mean residues of chlorsulfuron 

in various food items based on a single application at 0.0625 lbs a.i./A. EPA’s estimates of 

chlorsulfuron residues on various wild animal food items are summarized in Table 12. No monitoring 

data were available to use to estimate the terrestrial EECs. 

Table 12. EECs of Chlorsulfuron on Wild Animal Food Items 

Food Item 

EEC (ppm) 

Predicted Maximum Residue Predicted Mean Residue 

Short grass 15.00 5.31 

Tall grass 6.88 2.25 

Broadleaf/forage plants and small insects 1 8.44 2.81 

Seeds 0.94 0.44 

Surface to volume ratios of broadleaf plants and insects are similar; therefore, EPA assumes that they 

contain similar residue levels. 

Exposure to Plants 

A refined spray drift assessment was performed to better characterize the potential risk to nontarget plants at varying distances from a chlorsulfuron-treated field. This assessment considered both 

ground and aerial application, maximum application rates for pasture and rangeland and typical 

application rates for wheat, and a variety of wind speeds and droplet size spectra. 

17
c. Environmental Risk to Non-Target Organisms 

As previously mentioned, EPA compares toxicity endpoints from ecological toxicity studies to 

EECs for chlorsulfuron and calculates risk quotients (RQs) to evaluate the potential risk to nontarget 

organisms. These RQs are then compared to the Agency's levels of concern (LOCs). The 

chlorsulfuron RQs show that acute LOCs are not exceeded for terrestrial or aquatic animals. Chronic 

LOCs are also not exceeded for terrestrial or aquatic animals. EPA does have risk concerns for both 

terrestrial and aquatic non-target plants. 

Risk to Aquatic Organisms 

Risk to Freshwater and Estuarine/Marine Fish. Acute and chronic risk quotients do not 

exceed the LOC for freshwater or marine/estuarine fish. With acute toxicity values (LC50s) greater than 

50 ppm and EECs less than 10 ppb, chlorsulfuron is not expected to pose an acute risk to aquatic 

animal species. Chronic toxicity tests result in NOECs that are greater than or equal to 20 ppm. 

Therefore, chlorsulfuron is expected to present low acute or chronic risks to freshwater and 

marine/estuarine fish. Both the acute and the chronic risk quotients for freshwater and estuarine/marine 

fish are less than 0.01, which is significantly below than the Agency’s LOC. 

Risk to Invertebrates. Acute and chronic risk quotients do not exceed the LOC for 

freshwater or marine/estuarine invertebrates. With acute toxicity values (LC50s) greater than 50 ppm 

and EECs less than 10 ppb, chlorsulfuron is not expected to pose an acute risk to aquatic animal 

species. Chronic toxicity tests result in NOECs that are greater than or equal to 20 ppm. Therefore, 

chlorsulfuron is expected to present low acute or chronic risks to freshwater and marine/estuarine 

invertebrates. Both the acute and the chronic risk quotients for freshwater and estuarine/marine 

invertebrates are less than 0.01, which is significantly less than the Agency’s LOC. 

Risk to Non-target Aquatic Plants. Screening-level RQs for non-target and 

endangered/threatened aquatic plants are reported in Table 13. The Agency’s LOC for non-target 

aquatic plants is exceeded in all modeled scenarios. The assessment uses the EC50 to assess risk to 

aquatic plants, since they generally have a shorter recovery period from potential population effects 

because their reproductive cycles are shorter than terrestrial plants. At current maximum application 

rates used on wheat, non-target aquatic plant RQs range from 12 to 16 and from 18 to 23 for 

endangered aquatic plant species. For use on turf (at the same rate as rangeland), RQs range from 17 

to 21 for non-target aquatic plants and from 26 to 31 for endangered aquatic plants. 

Table 13. Risk Quotients to Aquatic Plants from Runoff (LOC is 1.0) 

Aquatic Plants 1 

Crop Scenario: application 

Non-target Endangered 

Turf: ground 17 - 21 26 - 31 

18 
1 

Crop Scenario: application 

Aquatic Plants 1 

Non-target Endangered 

Grains: ground 

12 - 16 18 - 23 

Grains: aerial 

Past./Range: ground Not Assessed 

Past./Range: aerial Not Assessed 

Non-crop (industrial) ground Not Assessed 

PRZM/EXAMS was used to estimate peak Estimated Environmental Concentrations (EECs). 

Risk to Terrestrial Organisms 

Risk to Birds 

With acute toxicity values (LC50s) greater than 5,000 ppm and relatively low EECs, 

chlorsulfuron is not expected to pose an acute risk to avian species. The NOEC for avian reproduction 

(174 mg/kg/day) is more than an order of magnitude above the highest EEC. Both the acute and the 

chronic RQs for birds are less than 0.01, which is significantly less than the Agency’s level of concern. 

Risk to Mammals 

Because of low acute toxicity to laboratory rats, RQs do not exceed the LOCs for mammals 

for acute risks. Both the acute RQs for mammalian species is less than 0.01, which is significantly 

below the Agency’s level of concern. No data are currently available to assess the chronic risk to 

mammalian species, however, the registrant has recently submitted a two-generation reproduction study 

to the Agency for review. Preliminary results indicate that chronic risks are expected to be not of 

concern; therefore, these data are considered confirmatory. 

Risk to Insects 

RQ are not calculated for terrestrial insects; however, based on an acute contact study, 

chlorsulfuron is classified as practically nontoxic to honeybees. Therefore, the Agency expects direct 

risk to insects to be minimal. 

Risk to Terrestrial Non-target Plants 

The Agency’s screening-level risk assessment for terrestrial non-target plants does not address 

direct application to plants, as this risk is assumed to be inevitable with the use of an herbicide. The 

Agency conducted a refined assessment of the risk to terrestrial plants from the use of chlorsulfuron. 

Whereas the initial assessment includes RQs calculated from the most sensitive EC25 from guideline 

laboratory plant toxicity tests, the refined assessment looks at a range of effect levels (EC10 to EC90) for 

all the plants tested that might occur from exposure to spray drift only. The EC25 is considered more 

appropriate for assessing effects to terrestrial plant populations, which typically have a longer 

19
reproductive cycle than aquatic plants, and thus adverse effects on populations may require a greater 

recovery period. Additionally, because the actual distribution of plant responses cannot be assessed 

from the 10 species required in the guideline studies, conservative assumptions are used in the risk 

assessment. The risk to endangered species is estimated using the NOEC, a more sensitive endpoint 

than the EC25 used to estimate acute risk to non-listed plant species. 

The results of this assessment indicate that while the extent of potential risk depends on the 

application rates and conditions chosen, almost all of the scenarios indicate the potential for adverse 

effects to plants hundreds of feet from chlorsulfuron-treated fields. The assessment focuses on risk due 

to exposures from off-target drift or runoff from four scenarios: 

1. Off-target drift and runoff of chlorsulfuron from a one acre application site to an 

adjacent one acre terrestrial area using seedling emergence toxicity data to calculate 

risk quotients (Table 14), based on a single application of chlorsulfuron. 

2. Off-target drift and no runoff of chlorsulfuron from a one acre application site to an 

adjacent one acre terrestrial area using vegetative vigor toxicity data to calculate risk 

quotients (Table 14), based on a single application of chlorsulfuron. 

3. Off-target drift and runoff of chlorsulfuron from a ten acre application site to an 

adjacent one acre semi-aquatic area (wetland) using seedling emergence toxicity data 

to calculate risk quotients (Table 14), based on a single application of chlorsulfuron. 

4. Use of contaminated irrigation water (groundwater or surface water inadvertently 

containing chlorsulfuron) using the vegetative vigor toxicity data to calculate risk 

quotients (Table 15), based on a single irrigation event. 

RQs for ground application of chlorsulfuron to small grains (wheat, barley, and oats), pasture 

and rangeland range from 3 to 23 for non-target terrestrial plants and from 21 to 43 for 

endangered/threatened terrestrial plants. RQs for aerial application to small grains, pasture and 

rangeland range from 4 to 115 for non-target plants and from 28 to 213 for endangered/threatened 

plants. At the current maximum application rate of chlorsulfuron to small grains, rangeland and pasture, 

level of concerns are exceeded for non-target and endangered/threatened terrestrial plants. The 

application of chlorsulfuron to industrial areas results in the highest calculated RQs. Direct exposure 

scenarios were not calculated, but RQs for plants and endangered plants would be significantly higher 

than those estimated from exposure via spray drift and/or runoff. 

Screening-level RQs for semi-aquatic areas (wetlands) resulting from off-target drift 

(concentrations estimated at the edge of the treated field) and runoff of chlorsulfuron from the 

application site (ten acres to one acre) are presented in Table 14. The RQs range from 122 to 1552 

for endangered plants and from 18 to 230 for other non-target plants. 

20
Table 14. Risk Quotients to Plants from Drift and/or Runoff (LOC is 1.0) 

Crop Scenario: 

application 

Terrestrial Plants 1 RQs 

(drift and runoff) 

Terrestrial Plants 2 RQs 

(drift and no runoff) 

Semi-aquatic Plants 3 RQs 

(drift and runoff) 

Non-target Endangered Non-target Endangered Non-target4 Endangered5 

Turf: ground 2 - 4 16 - 30 12 - 23 22 - 43 20 - 38 133 - 255 

Grains: ground 3 - 4 21 - 30 16 - 23 30 - 43 26 - 38 177 - 255 

Grains: aerial 4 - 6 28 - 40 80 - 115 148 - 213 18 - 26 122 - 175 

Past./Range: 

ground 3 - 12 21 - 82 16 - 63 30 - 116 26 - 103 177 - 693 

Past./Range: aerial 4 - 16 28 - 109 80 - 313 148 - 580 18 - 71 122 - 476 

Non-crop 

(industrial) ground 4 - 27 40 - 83 12 - 140 22 - 259 38 - 230 255 - 1552 

1 Runoff modeled from one-acre application site to adjacent one-acre terrestrial area, using seedling 

emergence toxicity data based on single application 2 Drift from one-acre application site to one-acre adjacent terrestrial area, using vegetative vigor toxicity data 

based on single application 3 Runoff modeled from ten-acre application site to one-acre adjacent wetland, using seedling emergence 

toxicity data based on a single application 4 EEC/EC50 

5 EEC/NOEC 

These calculations suggest that non-target plants may be adversely affected through the use of 

irrigation water containing chlorsulfuron. Results of modeling suggest that using surface water for 

irrigation may increase the risk over groundwater irrigation because chlorsulfuron is more likely to 

contaminate surface water than it is groundwater. 

Additionally, this screening-level assessment indicates that irrigation water may inadvertently 

contain high enough levels of chlorsulfuron to adversely impact sensitive agricultural crops (such as 

soybeans, sugarbeets, onions, etc.) if they are grown in fields that are irrigated with water containing 

chlorsulfuron. RQs for sensitive crops within irrigated fields range from 36 for irrigation using 

groundwater to 136 for using surface water to irrigate fields. In regions where chlorsulfuron has been 

used historically, agricultural crops grown in fields irrigated with groundwater or surface water 

containing chlorsulfuron could possibly be adversely affected. This assessment assumed that no 

endangered plants occur within irrigated fields. 

21
Table 15. Risk Quotients for Non-target Plants Exposed to Irrigation Water1 

Risk Quotients 

Location 

EEC 

(lb ai/A)2 Non-endangered Plants 3

 (EEC/EC25) 

Endangered Plants 

(EEC/NOEC) 

Wetland and terrestrial Groundwater: 1.8 x 10-5 Groundwater: 2 Groundwater: 3 

areas adjacent to irrigated 

fields4 Surface water: 6.8 x 10-5 Surface water: 7 Surface water: 13 

Within the irrigated field 5 Groundwater: 3.6 x 10-4 

Surface water: 1.4 x 10-3 

Groundwater: 36 

Surface water: 136 N/A 6 

1 Irrigation water contains 1.6 ppb chlorsulfuron in groundwater or 6.0 ppb in surface water. 

2 Estimated Environmental Concentration assuming one inch of irrigation water is applied to the target field. 

3 Non-target plants in areas adjacent to the irrigated field or sensitive agricultural crops within irrigated field. 

4 Assumes 5% drift of irrigation water containing chlorsulfuron and no runoff of irrigation water. 

5 Irrigation water applied directly to agricultural crops that may be sensitive to chlorsulfuron. 

6 It is assumed that there are no endangered plants within agricultural fields that are irrigated. 

d. Endangered/Threatened Species 

Available data indicate that chlorsulfuron does not exceed the LOCs for endangered/threatened 

terrestrial or aquatic animals. However, the screening-level risk assessment for endangered species 

indicates that chlorsulfuron exceeds the acute LOC for endangered and threatened terrestrial and 

vascular aquatic plants. Thus, the Agency considers this to be indicative of a potential for adverse 

effects to those listed species that rely either on a specific plant species (plant species obligate) or 

multiple plant species (plant dependant) for some important aspect of their life cycle. Further analysis 

regarding the overlap of individual species with each use site is required prior to determining the 

likelihood of potential impact to listed species.

 Chlorsulfuron was included in the small grains cluster consultation with the Fish and Wildlife 

Service (FWS) in 1983. As chlorsulfuron’s risks were assigned a “no effect” determination with regard 

to aquatic and terrestrial animals, Reasonable and Prudent Alternatives and Reasonable and Prudent 

Measures were not provided for this pesticide. Risks to endangered plants were not considered in this 

Biological Opinion. The FWS completed the rangeland cluster Biological Opinion in December 1984. 

Although chlorsulfuron was included in this Opinion, it did not consider endangered plants nor the 

potential indirect effects of chlorsulfuron on listed animals. 

Action Area 

For listed species assessment purposes, the action area is considered to be the area affected 

directly or indirectly by the Federal action and not merely the immediate area involved in the action. At 

the initial screening-level, the risk assessment considers broadly described taxonomic groups and so 

conservatively assumes that listed species within those broad groups are co-located with the pesticide 

22
treatment area. This means that terrestrial plants and wildlife are assumed to be located on or adjacent 

to the treated site and aquatic organisms are assumed to be located in a surface water body adjacent to 

the treated site. The assessment also assumes that the listed species are located within an assumed 

area, which has the relatively highest potential exposure to the pesticide, and that exposures are likely to 

decrease with distance from the treatment area. 

If the assumptions associated with the screening-level action area result in RQs that are below 

the listed species LOCs, a "no effect" determination conclusion is made with respect to listed species in 

that taxa, and no further refinement of the action area is necessary. Furthermore, RQs below the listed 

species LOCs for a given taxonomic group indicate no concern for indirect effects upon listed species 

that depend upon the taxonomic group covered by the RQ as a resource. However, when the 

screening assumptions lead to RQs in excess of the listed species’ LOCs for a given taxonomic group, 

a potential for a "may affect" conclusion exists and may be associated with direct effects on listed 

species belonging to that taxonomic group or may extend to indirect effects upon listed species that 

depend upon that taxonomic group as a resource. In such cases, additional information on the biology 

of listed species, the locations of these species, and the locations of use sites could be considered along 

with available information on the fate and transport properties of the pesticide to determine the extent to 

which screening assumptions regarding an action area apply to a particular listed organism. These 

subsequent refinement steps could consider how this information would impact the action area for a 

particular listed organism and may potentially include areas of exposure that are downwind and 

downstream of the pesticide use site. 

Taxonomic Groups Potentially at Risk 

The RQs calculated based on the ratio of estimated environmental concentrations (EECs) to 

toxicity endpoints, in this case the NOEC from plant toxicity studies, indicate potential to affect 

endangered plants should exposure to chlorsulfuron through spray drift or runoff occur. 

Should estimated exposure levels occur in proximity to listed resources, the available screeninglevel information suggests a potential concern for direct effects on listed plant species associated with 

use of chlorsulfuron, particularly wheat and pasture/rangeland. This Level I screening assessment is 

based on the initial assumption that listed species within the taxonomic groups of concern are actually 

present in areas for which the estimated exposure levels used for RQ calculation can be expected to 

occur. A specific determination of “may affect” for any RQ in excess of listed species LOCs cannot be 

made until a determination of the co-occurrence of the listed species with the action area has been 

determined. 

Indirect Effects Analysis 

Because plant RQs are above non-endangered species LOCs, the Agency considers this to be 

indicative of a potential for effects to those listed species that rely either on a specific plant species 

23
(plant species obligate) or multiple plant species (plant dependant) for some important aspect of their 

life cycle. The extent to which the use of chlorsulfuron on wheat and pasture/rangeland will indirectly 

affect listed animal species will require identification of listed species that co-occur in areas of 

chlorsulfuron use and an evaluation of critical habit as described below. Because of the national extent 

of the labeled uses of chlorsulfuron, we cannot preclude the possibility of a “may affect” for all listed 

animals, given the current extent of analysis of exposure, effects, and co-occurrence of listed species 

and areas of use. 

Critical Habitat 

The screening-level risk assessment has identified potential concerns for indirect effects on 

listed species for those organisms dependant upon plants sensitive to chlorsulfuron. In light of the 

potential for indirect effects, the next step for the Agency and the Service(s) is to identify which listed 

species and critical habitat are potentially implicated. Analytically, the identification of such species and 

critical habitat can occur in either of two ways. First, the agencies could determine whether the action 

area overlaps critical habitat or the occupied range of any listed species. If so, the Agency would 

examine whether the pesticide's potential impacts on non-endangered species would affect the listed 

species indirectly, or directly affect a constituent element of the critical habitat. Alternatively, the 

agencies could determine which listed species depend on biological resources, or have constituent 

elements that fall into the taxa, that may be directly or indirectly impacted by the pesticide. Then the 

Agency would determine whether use of the pesticide overlaps the critical habitat or the occupied range 

of those listed species. At present, the information reviewed by the Agency does not permit use of 

either analytical approach to make a definitive identification of species that are potentially impacted 

indirectly or critical habitats that is potentially impacted directly by the use of the pesticide. The Agency 

and the Service(s) will work together to conduct the necessary analysis. 

This screening-level risk assessment for critical habitat provides a listing of potential biological 

features that, if they are constituent elements of one or more critical habitats, would be of potential 

concern. These correspond to the taxa identified above as being of potential concern for indirect 

effects and include birds, mammals, terrestrial-phase amphibians, reptiles, fish, aquatic invertebrates 

and aquatic-phase amphibians. This list should serve as an initial step in problem formulation for further 

assessment of critical habitat impacts outlined above. 

Co-occurrence Analysis 

The goal of the analysis for co-location is to determine whether sites of pesticide use are 

geographically associated with known locations of listed species. At the screening-level, this analysis is 

accomplished using the Agency’s LOCATES database. The database uses location information for 

listed species at the county level and compares it to agricultural census data for crop production at the 

same county level of resolution. The product is a listing of federally listed species that are located within 

states known to produce the crop upon which the pesticide will be used. Because the Level I screening 

24
assessment considers both direct and indirect effects across generic taxonomic groupings, it is not 

possible to exclude any taxonomic group from a LOCATES database run for a screening risk 

assessment. 

Although use data is available, the labeled wheat usage allows for nationwide application. 

Additionally, the LOCATES database does not have a pasture/rangeland co-occurrence search 

capacity at the present time. As noted previously, at the screening-level, it is not possible to evaluate all 

the potential indirect effects that could impact endangered animals, because the potential biological 

significance of the interdependency between directly affected plants and potentially adversely affected 

animals requires species-specific analysis. Therefore, we cannot preclude the possibility of a “may 

effect” designation all listed animals at the current extent of this analysis. 

e. Ecological Incident Reports 

Results from a number of field studies, greenhouse studies and laboratory studies suggest that 

chlorsulfuron applied at labeled rates may result in high risk to non-target plants grown in the vicinity of 

application sites. Several researchers have concluded that these studies indicate that small quantities of 

chlorsulfuron change plant reproduction without altering vegetative growth. If the effect of chlorsulfuron 

on cherry trees is characteristic of other plant species, spray drift may severely reduce both the crop 

yields and fruit development on plants, the keystone component of the habitat and food web for wildlife. 

Plant reproductive processes may be more sensitive to chlorsulfuron than growth effects. Low levels of 

chlorsulfuron appear to adversely influence plant reproduction, which is not characteristic of many 

common herbicides. For a complete discussion of the field and greenhouse studies, please see the 

document entitled, “Revised Environmental Fate and Ecological Risk Assessment of Chlorsulfuron,” 

listed in Appendix C. 

There is uncertainty regarding the extent to which the incident data can be associated with 

chlorsulfuron alone. Additionally, while the risks to non-target plants from direct application of 

chlorsulfuron have not been estimated quantitatively in this risk assessment, RQs for direct application 

to plants are expected to be higher than those estimated for indirect exposure through runoff and/or 

drift. 

There are five non-target plant incidents that may be linked to offsite drift of chlorsulfuron in the 

Agency’s Ecological Incident Information System (EIIS) database. The most recent of these incidents 

(incident #I013884-012) occurred in June 1998 in Benton County, WA, where an orchard bound on 

three sides by “dry land” wheat reported four years of reduced Bing cherry production. The 

Washington State Department of Agriculture investigated the allegation, but the cause remains unknown 

and the investigation was not continued. Chlorsulfuron was one of the herbicides used on the wheat 

fields. 

25
While not in the Agency’s EIIS database, an alleged incident of chlorsulfuron drift was 

investigated by Fletcher (1991). An orchard suffered several years of reduce yield in the late 1980s in 

an area proximal to wheat farms at Horse Heaven Hills, where herbicides were regularly used. While 

the reduced yields and plant damage were not noted before the use of chlorsulfuron in the area, the 

investigation results were inconclusive. 

IV. Risk Management and Reregistration Decision 

A. Determination of Reregistration Eligibility 

Section 4(g)(2)(A) of Federal Insecticide, Fungicide and Rodenticide Act (FIFRA) calls for the 

Agency to determine, after submissions of relevant data concerning an active ingredient, whether 

pesticides containing the active ingredient are eligible for reregistration. The Agency has previously 

identified and required the submission of the generic (i.e., an active ingredient specific) data required to 

support reregistration of products containing chlorsulfuron as the active ingredient. 

The Agency has completed its assessment of the residential, occupational, and ecological risks 

associated with the use of pesticides containing the active ingredient chlorsulfuron as well as a 

chlorsulfuron-specific dietary risk assessment. Based on a review of these data and public comments 

on the Agency’s assessments for the active ingredient chlorsulfuron, EPA has sufficient information on 

the human health and ecological effects of chlorsulfuron to make decisions as part of the tolerance 

reassessment process under Federal Food, Drug and Cosmetic Act (FFDCA) and reregistration under 

FIFRA, as amended by the Food Quality Protection Act (FQPA). The Agency has determined that 

currently registered uses of chlorsulfuron will not pose unreasonable risks or adverse effects to humans 

or the environment if the risk mitigation measures and label changes outlined in the RED are 

implemented. The Agency has determined that chlorsulfuron is eligible for reregistration. These 

products will be reregistered provided that the required product specific data, confidential statements 

of formula and revised labeling outlined in this document are received and accepted by EPA. Products 

which contain ingredients in addition to chlorsulfuron will be reregistered when all of their other active 

ingredients also are reregistered. Label changes are described in Section V. Appendix B identifies the 

generic data requirements that the Agency reviewed as part of its determination of reregistration 

eligibility of chlorsulfuron and lists the submitted studies that the Agency found acceptable. 

The Agency believes that specific drift language amendments proposed in this RED will 

substantially reduce, though may not completely eliminate, the risks to non-target plants. The Agency 

intends to conduct an additional assessment of chlorsulfuron, and may consider other similar herbicides, 

at a later date. Reviewing these pesticides as a possible group will allow the Agency to assess the risks 

from all of these pesticides simultaneously, rather than individually on a case-by-case basis. A 

cohesive, comprehensive decision to protect non-target plants (including endangered and threatened 

26
species) can then be implemented more consistently for all pesticides in the group. The Agency intends 

to initiate this review after August 3, 2006. 

B. Summary of Public Comments 

When making its reregistration decision, the Agency took into account all comments received 

during Phase 3 of the public participation process for reregistration. These comments in their entirety 

are available in the public docket, under docket number OPP-2004-0219. DuPont, the technical 

registrant for chlorsulfuron, and several interested growers and grower groups submitted comments. 

The Agency has prepared responses to each of these comments, which are also available from Public 

Docket at http://www.epa.gov/edocket under docket #OPP-2004-0219. A summary of selected 

comments is provided below. 

C Benefits information was provided by several users and user groups. Although the 

Agency not completed a comprehensive benefits assessment at this time, it has 

considered this information in formulating this RED. 

C DuPont submitted risk assessments for several products which compete with 

chlorsulfuron in the cereal and fallow herbicide market. The purpose of the risk 

assessment for the chlorsulfuron RED is not to compare the environmental fate 

properties of chlorsulfuron to its alternatives, but rather to assess potential risks from 

the use of chlorsulfuron. 

C DuPont also submitted extensive comments on some of the data and assumptions 

underlying the ecological risk assessment. The Agency considered this information, and 

incorporated it where applicable (such as using new plant toxicity data). A detailed 

response is available in the docket. 

C. Regulatory Position 

1. FQPA Assessment 

a. “Risk Cup” Determination 

As part of the FQPA tolerance reassessment process, EPA assessed the risks associated with 

the use of chlorsulfuron. The assessment is for this individual pesticide only. FQPA requires the 

Agency to evaluate food tolerances on the basis of cumulative risk from substances sharing a common 

mechanism of toxicity. For purposes of tolerance reassessment and determination of reregistration 

eligibility of chlorsulfuron, EPA is assuming that chlorsulfuron does not share a common mechanism of 

toxicity with other compounds. 

27
Chlorsulfuron dietary and residential aggregate risks were assessed in an Agency action 

published in the Federal Register on August 14, 2002 (volume 67, number 157). This action 

established new tolerances for residues for chlorsulfuron in or on grass, forage and grass hay. This 

action also reassessed all other existing tolerances of chlorsulfuron as required by the Federal Food, 

Drug and Cosmetic Act (FFDCA), as amended by FQPA. 

b. Endocrine Disruptor Effects 

EPA is required under the FFDCA, as amended by FQPA, to develop a screening program to 

determine whether certain substances (including all pesticide active and other ingredients) "may have an 

effect in humans that is similar to an effect produced by a naturally occurring estrogen, or other such 

endocrine effects as the Administrator may designate." Following the recommendations of its 

Endocrine Disruptor Screening and Testing Advisory Committee (EDSTAC), EPA determined that 

there were scientific bases for including, as part of the program, the androgen and thyroid hormone 

systems, in addition to the estrogen hormone system. EPA also adopted EDSTAC’s recommendation 

that the Program include evaluations of potential effects in wildlife. For pesticide chemicals, EPA will 

use FIFRA and, to the extent that effects in wildlife may help determine whether a substance may have 

an effect in humans, FFDCA authority to require the wildlife evaluations. As the science develops and 

resources allow, screening of additional hormone systems may be added to the Endocrine Disruptor 

Screening Program (EDSP). When the appropriate screening and/or testing protocols being 

considered under the Agency’s EDSP have been developed, chlorsulfuron may be subjected to 

additional screening and/or testing to better characterize effects related to endocrine disruption. 

c. Tolerance Summary 

As mentioned earlier, chlorsulfuron dietary and residential aggregate risks were assessed in an 

Agency action published in the Federal Register on August 14, 2002 (volume 67, number 157). This 

action established new tolerances for residues for chlorsulfuron in or on grass, forage and grass hay. 

This action also reassessed all other existing tolerances of chlorsulfuron as required by the FFDCA, as 

amended by FQPA. This notice is available on the internet at: 

http://www.epa.gov/EPA-PEST/2002/August/Day-14/p20229.htm. 

1. Benefits Discussion 

EPA believes that plant growth regulators and sulfonylureas are likely alternatives for 

chlorsulfuron. Although 2,4-D or metsulfuron are the most likely alternatives; there are several other 

plant growth regulators and sulfonylurea herbicides, both single and multiple active ingredient products, 

that may also be used. The treatment cost of alternatives does not appear to be significantly different 

from the treatment cost of chlorsulfuron or chlorsulfuron combined with metsulfuron. Therefore, 

pesticide choice by growers to control weeds would also depend on such factors as the product 

28
efficacy, method of application, and other application costs; however, these factors were not quantified 

in this analysis. 

Table 16 provides the percent of winter wheat acres treated by chlorsulfuron and four other 

alternative herbicides. The total number of acres harvested in the surveyed states were 22.2 million. 

Table 16. Percent of Winter Wheat Treated with Herbicides in U.S., 2002 

Herbicide Percent US Acres 

Treated 

Percent OK Acres 

Treated 

Percent KS Acres 

Treated 

2,4-D 13 8 6 

Metsulfuron-methyl 13 19 16 

Chlorsulfuron 10 18 18 

Sulfosulfuron 6 13 3 

Tribenuron-methyl 5 NA NA 

Source: NASS Agricultural Chemical Usage, Field Crop Summary 2002, May 2003 

NA = Not Available 

Chlorsulfuron (Glean®) is registered for control of broadleaf weeds and a few grass weeds. In 

Oklahoma and Kansas, chlorsulfuron commonly targets: wild mustard, wild buckwheat, redroot 

pigweed, kochia and henbit (EPA proprietary data). Of these weeds, chlorsulfuron claims partial 

control of kochia and wild buckwheat. The Crop Profile for Winter Wheat in Kansas mentions henbit, 

wild buckwheat, and kochia as common weeds in wheat fields (Crop Profile for Winter Wheat in 

Kansas, 1999). 

Chlorsulfuron is often applied in combination with metsulfuron-methyl as the product, Finesse®. 

Mesosulfuron-methyl, registered in 2004 for use on wheat, has some limited overlap with chlorsulfuron. 

This herbicide is registered for control of grass weeds, but does not target some broadleaf weeds, such 

as wild mustard, henbit and redroot pigweed. 

Based on comments received during the RED process, discussions with extension specialists, 

and its own analysis, the Agency believes that growth regulators and sulfonylureas are likely alternatives 

for chlorsulfuron. Of the alternatives, EPA believes 2,4-D or metsulfuron-methyl are most commonly 

used. There are a number of other growth regulators and sulfonylurea herbicides, as well as 

combination products, available that may also be used. The cost of alternatives does not appear to be 

significantly different from the cost of chlorsulfuron and chlorsulfuron combined with metsulfuronmethyl. 

29
D. Regulatory Rationale 

EPA has determined that certain mitigation measures and label amendments are necessary for 

the currently registered uses of chlorsulfuron to be eligible for reregistration. The following is a 

summary of the rationale for managing occupational and ecological risks associated with the current use 

of chlorsulfuron. Where labeling revisions are warranted, specific language is set forth in the summary 

tables of Section V of this document. 

1. Human Health Risk Mitigation 

a. Dietary, Homeowner and Aggregate Mitigation 

Because these risks were addressed during the tolerance reassessment of chlorsulfuron, no 

further mitigation of dietary, homeowner, or aggregate risks is needed at this time. 

b. Occupational Risk Mitigation 

Agricultural Handler Risk 

There are no risks of concern for agricultural handlers as summarized in Table 4. When 

handlers are wearing baseline attire (long sleeve shirt, long pants, shoes, and socks), MOEs are greater 

than 100 and are therefore not of concern. Chlorsulfuron labels will be amended to explicitly state that 

all handlers must wear baseline attire. 

Post-Application Worker Risk 

Because chlorsulfuron is used early in the season on crops/areas that have little worker activity, 

no post-application exposure is expected. Therefore, no post-application risks have been assessed. 

Based on preliminary eye and skin irritation studies, the Agency believes that a 12-hour 

Restricted Entry Interval (REI) would be sufficiently protective for chlorsulfuron. These preliminary 

data will be formally reviewed to confirm the toxicity category before placing the 12-hour REI on 

current labels. 

Chlorsulfuron also continues to be a candidate for a 4-hour REI. PR Notice 95-3 provides 

instructions and criteria for evaluating an end-use product to determine whether the 12-hour REI may 

be reduced to 4 hours. End-use products that currently contain a 4-hour REI may remain unchanged. 

2. Environmental Risk Mitigation 

30 
Terrestrial and Aquatic Animal Risk 

EPA has no concerns about the risk to terrestrial or aquatic animals potentially exposed to 

chlorsulfuron via runoff, so no mitigation is necessary. 

Insect Risk 

Risk quotients are not calculated for terrestrial insects; however, based on an acute contact 

study, chlorsulfuron is classified as practically nontoxic to honeybees. Therefore, direct risk to insects is 

expected to be minimal. 

Non-target Plant Risk 

As mentioned earlier, screening-level risk quotients (RQs) for non-target and 

endangered/threatened aquatic plants range from 12 to 21 for non-target aquatic plants and from 18 to 

31 for endangered aquatic plants. Likewise, RQs for terrestrial plants from the use on small grains 

range from 2 to 313 for non-target plants and from 16 to 1552 for endangered or threatened plants. 

Direct exposure scenarios were not calculated, but RQs for plants and endangered plants would be 

significantly higher than those estimated from exposure via spray drift and/or runoff. 

Because chlorsulfuron is an herbicide and may therefore harm non-target plants exposed via 

drift, the Agency requires that chlorsulfuron be applied in a manner that minimizes spray drift. Strict use 

restrictions to minimize spray drift will be placed on the labels for all chlorsulfuron products. This 

language will include: 

– Application must be made using a Coarse or Very Coarse droplet spectrum (ASAE 

S572) 

– Prohibit applications into temperature inversions 

– Allow only one application per growing season, except for industrial use sites where 

total pounds applied per year may not exceed 0.125 lb ai/A (based on comments 

submitted by Pacific Gas and Electric Company) 

– Restrictions on pressure settings 

– Drift advisory language specifying further parameters that may be adjusted to reduce 

drift 

– Restrict distance between outer-most operating nozzles on the boom and wingspan or 

rotor width 

– Restrict application to industrial use sites to ground application only, except for rightsof-way where application by helicopter is permitted 

– Limit application to fine turf and ornamentals to spot treatment only where the area 

being treated does not exceed 240 square yards per acre. This mitigation will ensure 

31
that the application rate per acre to fine turf is no higher than the rate for unimproved 

industrial turf. 

In addition, the technical registrant has agreed to conduct a special study to evaluate the risk to 

non-target plants exposed to small droplets of chlorsulfuron. The Agency is concerned with the 

potential for adverse reproductive effects of chlorsulfuron on off-site non-target plant species. Such 

effects can have consequences to plant populations and community dynamics, as well as to higher 

trophic-level organisms. Studies performed by Fletcher et al. (1993, 1995, 1996) and Bhatti et al. 

(1995) demonstrate that extremely low concentrations (e.g. 1/1000th of label rates) of chlorsulfuron 

cause significant (40-99%) reductions in seed production in a variety of plant species. The registrant 

has agreed to conduct a special study to determine whether these studies are indicative of effects from 

exposure reasonably expected due to spray drift. The Agency will work with the registrant to develop 

appropriate protocols with which this uncertainty can be minimized. The protocols should build on 

previous work (e.g. similar phenologic timing of application) and include ecologically relevant plant 

species. EPA will evaluate risks to non-target plants, and any additional mitigation, after these studies 

are repeated and acceptable data have been submitted and reviewed. 

The Agency believes that specific drift language amendments proposed in this RED will 

substantially reduce, though may not completely eliminate, the risks to non-target plants. The Agency 

intends to conduct an additional assessment of chlorsulfuron, and may consider other similar herbicides, 

at a later date. Reviewing these pesticides as a possible group will allow the Agency to assess the risks 

from all of these pesticides simultaneously, rather than individually on a case-by-case basis. A 

cohesive, comprehensive decision to protect non-target plants (including endangered and threatened 

species) can then be implemented more consistently for all pesticides in the group. The Agency intends 

to initiate this review after August 3, 2006. 

3. Other Labeling 

In order to remain eligible for reregistration, other use and safety information must be placed on 

the labeling of all end-use products containing chlorsulfuron. For specific labeling statements, refer to 

Section V of this document 

a. Endangered Species Statement 

Available data indicate that chlorsulfuron does not exceed the LOCs for endangered/threatened 

terrestrial or aquatic animals. However, the screening-level risk assessment for endangered species 

indicates that chlorsulfuron exceeds the acute LOC for endangered and threatened terrestrial and 

vascular aquatic plants. Thus, the Agency considers this to be indicative of a potential for adverse 

effects to those listed species that rely either on a specific plant species (plant species obligate) or 

multiple plant species (plant dependant) for some important aspect of their life cycle. Further analysis 

32
regarding the overlap of individual species with each use site is required prior to determining the 

likelihood of potential impact to listed species. 

EPA is not requiring specific label language at the present time relative to threatened and 

endangered species. The general risk mitigation required through this RED will serve to reduce the risk 

to listed species of potential concern until such time as the Agency refines its analysis. 

b. Spray Drift Management 

The Agency has been working closely with stakeholders to develop improved approaches for 

mitigating risks to human health and the environment from pesticide spray and dust drift. As part of the 

reregistration process, we will continue to work with all interested parties on this important issue. 

From its assessment of chlorsulfuron, as summarized in this document, the Agency concludes 

that certain measures are needed to address the potential for off-target drift from chlorsulfuron 

products. Label statements implementing these measures are listed in the Spray Drift section of the 

label table (Table 16) in Chapter V of this RED document. In the future, chlorsulfuron product labels 

may need to be revised to include additional or different drift label statements. 

V. What Registrants Need to Do 

The Agency has determined that chlorsulfuron is eligible for reregistration provided that: (i) 

additional data are submitted to confirm this decision; (ii) the risk mitigation measures outlined in this 

document are adopted; and (iii) label amendments are made to reflect these measures. To implement 

the risk mitigation measures, the registrants will be required to amend their product labeling to 

incorporate the label statements set forth in the Label Summary Table in Section C below. In the near 

future, the Agency intends to issue Data Call-In Notices (DCIs) requiring label amendments, product 

specific data and additional generic (technical grade) data. Generally, registrants will have 90 days 

from receipt of a DCI to complete and submit response forms or request time extension and/or waiver 

requests with a full written justification. For product specific data, the registrant will have eight months 

to submit data and amended labels. For generic data, due dates can vary depending on the specific 

studies being required. Below are tables of additional generic data and label amendments that the 

Agency intends to require for chlorsulfuron to be eligible for reregistration. 

A. Manufacturing Use Products 

1. Additional Generic Data Requirements 

The generic data base supporting the reregistration of chlorsulfuron for the above eligible uses 

has been reviewed and determined to be substantially complete. However, the data listed below are 

necessary to confirm the reregistration eligibility decision documented in this RED. 

33
Table 16. Data Requirements for the Reregistration Eligibility Decision on Chlorsulfuron 

Guideline Study Name New OPPTS 

Guideline No. 

Old Guideline 

No. 

UV/Visible Absorption 830.7050 None 

21-Day Dermal Toxicity 870.3200 82-2 

90-day Inhalation Toxicity 870.3465 82-4 

Two-Generation Reproduction 870.3800 83-4 

Plant Toxicity – Effects from small droplets Special Study 

2. Labeling for Manufacturing-Use Products 

To ensure compliance with FIFRA, manufacturing use product (MUP) labeling should be 

revised to comply with all current EPA regulations, PR Notices, and applicable policies. The MUP 

labeling should bear the labeling contained in Table 17. 

B. End-Use Products 

1. Additional Product-Specific Data Requirements 

Section 4(g)(2)(B) of FIFRA calls for the Agency to obtain any needed product-specific data 

regarding the pesticide after a determination of eligibility has been made. The Registrant must review 

previous data submissions to ensure that they meet current EPA acceptance criteria and if not, commit 

to conduct new studies. If a registrant believes that previously submitted data meet current testing 

standards, then the study MRID numbers should be cited according to the instructions in the 

Requirement Status and Registrants Response Form provided for each product. The Agency intends to 

issue a separate product-specific data call-in (PDCI), outlining specific data requirements. 

2. Labeling for End-Use Products 

To be eligible for reregistration, labeling changes are necessary to implement measures outlined 

in Section IV above. Specific language to incorporate these changes is specified in Table 17. 

Generally, conditions for the distribution and sale of products bearing old labels/labeling will be 

established when the label changes are approved. However, specific existing stocks time frames will be 

established case-by-case, depending on the number of products involved, the number of label changes, 

and other factors. 

34
C. Labeling Changes Summary Table 

In order to be eligible for reregistration, all product labels must be amended to incorporate the 

risk mitigation measures outlined in Section IV. The following table (Table 17) describes how to 

amend the language on the labels. 

35
Table 17. Summary of Labeling Changes for Chlorsulfuron 

Description Amended Labeling Language Placement on Label 

Manufacturing Use Products 

For all Manufacturing 

Use Products 

“Only for formulation into an herbicide for the following use(s) [fill blank only with those uses that are 

being supported by MP registrant].” Directions for Use 

One of these statements “This product may be used to formulate products for specific use(s) not listed on the MP label if the 

may be added to a label to formulator, user group, or grower has complied with U.S. EPA submission requirements regarding 

allow reformulation of the support of such use(s).” 

product for a specific use Directions for Use 

or all additional uses “This product may be used to formulate products for any additional use(s) not listed on the MP label 

supported by a formulator if the formulator, user group, or grower has complied with U.S. EPA submission requirements 

or user group regarding support of such use(s).” 

"Do not discharge effluent containing this product into lakes, streams, ponds, estuaries, oceans, or 

Environmental Hazards other waters unless in accordance with the requirements of a National Pollution Discharge Elimination 

Statements Required by 

the RED and Agency 

System (NPDES) permit and the permitting authority has been notified in writing prior to discharge. 

Do not discharge effluent containing this product to sewer systems without previously notifying the Directions for Use 

Label Policies local sewage treatment plant authority. For guidance contact your State Water Board or Regional 

Office of the EPA." 

End Use Products Intended for Occupational Use 

PPE Requirements “Personal Protective Equipment (PPE)” Immediately 

Established by RED1 following/below 

for all end-use products “Mixers, loaders, applicators, and other handlers must wear: Precautionary Statements: 

intended for occupational Long-sleeved shirt and long pants Hazards to Humans and 

use Shoes plus socks.” Domestic Animals 

Precautionary Statements: 

User Safety Requirements “Follow manufacturer's instructions for cleaning/maintaining PPE. If no such instructions for 

washables exist, use detergent and hot water. Keep and wash PPE separately from other laundry.” 

Hazards to Humans and 

Domestic Animals 

(Immediately after PPE 

Requirements.) 

36 
Description Amended Labeling Language Placement on Label 

“User Safety Recommendations 

User Safety 

Recommendations 

Users should wash hands before eating, drinking, chewing gum, using tobacco, or using the toilet. 

Users should remove clothing/PPE immediately if pesticide gets inside. Then wash thoroughly and 

put on clean clothing. 

Users should remove PPE immediately after handling this product. Wash the outside of gloves before 

removing2 . As soon as possible, wash thoroughly and change into clean clothing.” 

Precautionary Statements 

immediately following 

User Safety Requirements 

(Must be placed in a box.) 

Environmental Hazards 

“Do not apply directly to water, or to areas where surface water is present or to intertidal areas below 

the mean high water mark. Do not contaminate water when disposing of equipment washwater or 

rinsate.” 

Precautionary Statements 

immediately following the 

User Safety 

Recommendations 

Restricted-Entry Interval 

For products containing chlorsulfuron as the sole active ingredient: 

“Do not enter or allow worker entry into treated areas during the restricted entry interval (REI) of 12 

hours:” 

NOTE: This active ingredient continues to be a candidate for a 4-hour REI. The end-use product 

registrant may follow the instructions in PR Notice 95-3 to evaluate the end-use product using the 

criteria described within the PRN to determine if the default 12-hour REI may be reduced to 4 hours. If 

the end-use product currently contains a 4-hour REI, then that 4-hour REI may be retained. The 

correct statement for a 4-hour REI is: 

“Do not enter or allow worker entry into treated areas during the restricted entry interval (REI) of 4 

hours:” 

Directions for Use, 

Agricultural Use 

Requirements Box 

“PPE required for early entry to treated areas that is permitted under the Worker Protection Standard 

Early Re-entry Personal and that involves contact with anything that has been treated, such as plants, soil, or water, is: 

Protective Equipment * coveralls, 

established by the RED. * shoes plus socks 

* chemical-resistant gloves made of any waterproof material” 

37
Description Amended Labeling Language Placement on Label 

“Avoid drift at the application site. This product should be applied only when the potential for drift to 

adjacent sensitive areas (e.g., residential areas, bodies of water, known habitat for threatened or 

endangered species, non-target crops, native plant communities) is minimal (e.g. when wind is blowing 

away from the sensitive areas). Avoid application under conditions that may allow spray drift since 

very small quantities of spray may seriously injure susceptible crops during either active growth 

periods or dormancy. Follow the additional precautions below to minimize the potential for spray drift. 

The interaction of many equipment and weather-related factors determines the potential for spray drift. 

The user is responsible for considering all these factors when making application decisions. 

Spray Drift Language for 

all products applied 

outdoors (including 

ground boom and aerial 

application) 

Where states have more stringent regulations, they must be observed. The applicator should be 

familiar and take into account the information covered in the following: 

Drift Control Adjuvants 

A drift control adjuvant may be used to further reduce the potential for drift. If a drift control adjuvant 

is used, follow the use directions and precautions on the manufacturer's label. Do not use an adjuvant 

which increases viscosity with Microfoil, Thru-Valve booms, or other systems that cannot 

accommodate viscous sprays. 

Directions for Use 

Controlling Droplet Size: 

- Nozzle Type 

Use a nozzle type according to manufacturer’s specifications that is designed for the intended 

application and produces a Coarse to Very Coarse droplet size spectrum (ASAE S572) under 

application conditions. Applicators must consider nozzle orientation, nozzle pressure, and flight 

speed in determining droplet size. Nozzles should always be oriented in the manner that minimizes the 

effects of air shear. Solid stream nozzles oriented straight back produce the largest droplets and the 

lowest drift.” 

38
Description Amended Labeling Language Placement on Label 

[Controlling Droplet Size (continued)]: 

“Pressure 

Do not exceed the nozzle manufacturer’s recommended pressures. When higher flow rates are needed, 

use a higher-capacity nozzle instead of increasing pressure.” 

“Swath Adjustment 

When applications are made with a crosswind, the swath will be displaced downwind. Therefore, on 

the up and downwind edges of the field, the applicator must compensate for this displacement by 

adjusting the path of the application equipment upwind. Swath adjustment distance should increase 

with increasing drift potential. 

Wind 

Spray Drift Language for 

all products applied 

outdoors (including 

ground boom and aerial 

application) 

Drift potential is lowest with a sustained wind between 2-10 mph. However, many factors, including 

droplet size and equipment type, determine drift potential at any given wind speed. Application 

should be avoided during gusty conditions, and when winds are below 2 mph due to variable wind 

direction and high potential for a temperature inversion. Note: Local terrain can influence wind 

patterns. Every applicator should be familiar with local wind patterns and how they affect spray drift. 

Temperature and Humidity 

When making applications in low relative humidity, set up equipment to produce larger droplets to 

compensate for evaporation. Droplet evaporation is most severe when conditions are both hot and 

dry. 

Directions for Use 

Surface Temperature Inversions 

Applications must not occur during a local, surface temperature inversion because drift potential is 

high. Temperature inversions restrict vertical air mixing, which causes small suspended droplets to 

remain in a concentrated cloud. This cloud can move in unpredictable directions due to the light 

variable winds which are common during inversions. Temperature inversions are common on nights 

with limited cloud cover and light to no wind. They begin to form as the sun sets and often continue 

into the morning. Their presence can be indicated by ground fog; however, if fog is not present, 

inversions can also be identified by the movement of the smoke from a ground source or an aircraft 

smoke generator. Smoke that layers and moves laterally in a concentrated cloud (under low wind 

conditions) indicates an inversion, while smoke that moves upward and rapidly dissipates indicates 

good vertical air mixing.” 

39
Description Amended Labeling Language Placement on Label 

“Shielded Sprayers 

Spray Drift Language for 

products applied by 

ground equipment 

Shielding the boom or individual nozzles can reduce the effects of wind. However, it is the 

responsibility of the applicator to verify that the shields are preventing drift and not interfering with 

uniform deposition of the product. 

Boom Length/Height 

Setting the boom at the lowest referenced height (if specified) which provides uniform coverage 

reduces the exposure of droplets to evaporation and wind. The boom should remain level with the 

crop and have minimal bounce. Limit nozzle height to no greater than 4 feet above the top of the 

largest plants.” 

Directions for Use 

“Application Height 

Application more than 10 ft. above the canopy increases the potential for spray drift. Make 

Spray Drift Language for 

products applied aerially 

applications no higher than 10 feet above the top of the target vegetation, unless a greater height is 

required for aircraft safety. Making applications at the lowest height that is safe reduces exposure of 

droplets to evaporation and wind. Directions for Use 

Boom Length 

The boom length must not exceed 75% of the wing span for fixed wing aircraft or 90% for rotor blade 

helicopters. Using shorter booms decreases drift potential.” 

General Precautions and "Do not apply this product in a way that will contact workers or other people, either directly or Near the beginning of 

Restrictions through drift. Only protected handlers may be in the area during application." Directions for Use 

Cereal Grains: 

“Maximum of one application per growing season.” 

Application Restrictions 

Industrial Use sites (including rights-of-ways): 

“Application is restricted to ground application only, with the exception of rights-of-way, which may 

also be treated by helicopter.” 

“Do not apply more than three times per year. Do not apply more than 0.125 lbs ai/A per year.” 

Place in the Directions for 

Use under Application 

Instructions for Each 

Crop 

Fine turf and ornamentals: 

“Broadcast application to lawns is prohibited. Application is limited to spot treatments of 240 square 

yards or less per acre." 

40
Description Amended Labeling Language Placement on Label 

End Use Products Intended Primarily for Use by Homeowners 

Application Restrictions “Do not apply this product in a way that will contact any person or pet, either directly or through drift. 

Keep people and pets out of the area during application.” 

Directions for Use under 

General Precautions and 

Restrictions 

Entry Restriction “Do not allow people or pets to enter the treated area until sprays have dried.” 

Directions for Use under 

General Precautions and 

Restrictions 

1 PPE that is established on the basis of Acute Toxicity of the end-use product must be compared to the active ingredient PPE in this document. The more 

protective PPE must be placed in the product labeling. For guidance on which PPE is considered more protective, see PR Notice 93-7. 

2 Reference to gloves may be removed if the end-use product does not require gloves. 

Instructions in the Labeling section appearing in quotations represent the exact language that should appear on the label.

Instructions in the Labeling section not in quotes represents actions that the registrant should take to amend their labels or product registrations.

41
VI. Related Documents and How to Access Them 

A list of technical support documents for the chlorsulfuron RED is provided in Appendix C. All 

technical support documents for this RED may be viewed on paper in the OPP Public Docket or 

electronically via the Internet. These documents may be found on the Agency’s web page at 

www.epa.gov/pesticides/reregistration/status.htm (documents through April 2002) or at 

www.epa.gov.edockets under docket OPP-2003-0293 (Documents from May 2002 to the present). 

Hard copies of these documents may be found in the OPP public docket, under docket numbers OPP34241A or B, for documents dated through April 2002, or under docket number OPP-2003-0293, for 

documents dated from May 2002 to the present. The OPP public docket is located in Room 119, 

Crystal Mall II, 1801 S. Bell Street, Arlington, VA. The docket is open Monday through Friday, 

excluding Federal holidays, from 8:30 a.m. to 4:00 p.m. 

42
Appendix A 

Chlorsulfuron (Case 0631): Use Patterns Subject to Reregistration 

Application Timing, Type 

and Equipment 

Formulation 

[EPA Reg. No.] 

Maximum 

Single 

Application Rate 

Maximum 

Applications 

Per Season 

Maximum 

Seasonal 

Rate 

Preharvest 

Interval, 

Days 

Use Directions and Limitations 

Turf 

Preemergence, early 

postemergence, 

postemergence 

Hand-held sprayer, 

backpack sprayer 

Waterdispersible 

granule 

[228-375, 

10404-59] 

0.25 lb ai /A 2 0.5 lb ai/A Not 

Applicable 

Minimum retreatment interval is 60 days. 

Broadcast application to lawns is prohibited. 

Application is limited to spot treatments of 240 

square yards or less per acre. 

Non-Agricultural Rights-of-Way/Fencerows/Industrial Areas 

Preemergence, early 

postemergence 

Hand-held sprayer, boom 

sprayer, backpack sprayer, 

helicopter (rights-of-way 

only) 

Waterdispersible 

granule 

[352-522, 352­

404, 352-620, 352­

621] 

0.14 lb ai /A 1 0.14 lb ai/A Not 

Applicable 

Application is restricted to ground application 

only, with the exception of rights-of-way, 

which may also be treated by helicopter. 

Cereal Grains (Wheat, Barlet, Oats) 

Fallow, preplant, Postplant, 

Postemergence, 

Low volume ground 

sprayer, aircraft 

Waterdispersible 

granule 

[352-445, 352­

522] 

0.023 lb ai/A 1 0.023 lb ai/A 

Not 

Applicable 

(due to 

timing) 

43
APPENDIX B

Data Supporting Guideline Requirements for the Reregistration of Chlorsulfuron 

REQUIREMENT 

USE PATTERN CITATION(S) New Guideline Old Guideline Title Number Number 

PRODUCT CHEMISTRY 

830.1550 61-1 Product Identity and Composition 

830.1600 61-2A Start. Mat. & Mnfg. Process 

830.1670 61-2B Formation of Impurities 

830.1700 62-1 Preliminary Analysis 

830.1750 62-2 Certification of limits 

830.1800 62-3 Analytical Method 

830.6302 63-2

830.6303 63-3

830.6304 63-4

830.7050 None

830.7200 63-5

Color 

Physical State 

Odor 

UV/Visable Absorption 

Melting Point 

830.7220 63-6 Boiling Point 

830.7300 63-7 Density 

830.7840 63-8 Solubility 830.7860 

830.7950 63-9 Vapor Pressure 

All 42454101

All 42454101

All 42454101

All 42454101

All 42454101

All 42454102

All 42454102

All 42454102

All 42454102

All Data Gap

All 42454102

Not Applicable (substance is solid at room All temperature)

All 42454102

All 42454102, 42454103, 42454104

All 42454102, 42454105

44
Data Supporting Guideline Requirements for the Reregistration of Chlorsulfuron 

REQUIREMENT 

USE PATTERN CITATION(S) New Guideline Old Guideline Title Number Number 

830.7370 63-10 Dissociation Constant All 42454102, 42454106 

830.7550 63-11 Octanol/Water Partition 

Coefficient All 42454102, 42454107 

830.7000 63-12 pH All 42454102 

830.6313 63-13 Stability All 42454102, 42454108 

ECOLOGICAL EFFECTS 

850.2100 71-1 Avian Acute Oral Toxicity 00035263 

00035264 

850.2200 71-2A Avian Dietary Toxicity - Quail 00035265 

850.2200 71-2B Avian Dietary Toxicity - Duck 00035266 

850.2300 71-4A Avian Reproduction - Quail 42634001 

850.2300 71-4B Avian Reproduction - Duck 42634002 

850.1075 72-1A Fish Toxicity Bluegill 00035258 

850.1075 72-1C Fish Toxicity Rainbow Trout 41976405 

850.1010 72-2A Invertebrate Toxicity 00035262 

None 72-3A Estuarine/Marine Toxicity - Fish 41976401 

None 72-3B Estuarine/Marine Toxicity ­

Mollusk 41976403, 42328601 

None 72-3C Estuarine/Marine Toxicity ­

Shrimp 41976402, 41976408 

None 72-4A Fish- Early Life Stage 41976405 

45 
Data Supporting Guideline Requirements for the Reregistration of Chlorsulfuron 

REQUIREMENT 

USE PATTERN CITATION(S) New Guideline 

Number 

Old Guideline 

Number Title 

None 72-4B Estuarine/Marine Invertebrate 

Life Cycle 41976408 

850.4225 123-1(a) Seedling Emergence, Tier II 46361801 

850.4250 123-1(b) Vegetative Vigor, Tier II 46326801 

850.4400 123-2 Aquatic Plant Growth 

42186801 

45832901 

45832902 

45832903 

45832904 

TOXICOLOGY 

870.1100 81-1 Acute Oral Toxicity-Rat 00031406 

870.1200 81-2 Acute Dermal ToxicityRabbit/Rat 00083956 

870.1300 81-3 Acute Inhalation Toxicity-Rat 00086825 

870.2400 81-4 Primary Eye Irritation-Rabbit Data Gap 

870.2500 81-5 Primary Skin Irritation Data Gap 

870.2600 81-6 Dermal Sensitization Data Gap 

870.6100 81-7 Acute Delayed Neurotoxicity ­

Hen Not Required 

870.6200 81-8 Acute Neurotoxicity Screen Not Required 

870.3100 82-1A 90-Day Feeding - Rodent Satisfied by chronic study 

870.3150 82-1B 90-Day Feeding - Non-rodent 00031420 

46
Data Supporting Guideline Requirements for the Reregistration of Chlorsulfuron 

REQUIREMENT 

New Guideline 

Number 

Old Guideline 

Number Title 

USE PATTERN CITATION(S) 

870.3200 82-2 21-Day Dermal - Rabbit/Rat Data Gap 

870.3465 82-4 90-Day Inhalation-Rat Data Gap 

870.4100 83-1A Chronic Feeding Toxicity ­

Rodent 00086003 

870.4100 83-1B Chronic Feeding Toxicity -

Non-Rodent 41862601 

870.4200 83-2A Oncogenicity - Rat 00086003 

870.4200 83-2B Oncogenicity - Mouse 00090030 

870.3700 83-3A Developmental Toxicity - Rat 41976406 

870.3700 83-3B Developmental Toxicity - Rabbit 41983101 

870.3800 83-4 2-Generation Reproduction - Rat Data Gap 

870.4300 83-5 Combined Chronic Toxicity/ 

Carcinogenicity 00086003 

870.5100 84-2a Gene Mutation (Bacterial) Data Gap (MRID 00031425 may be upgraded) 

870.5300 None Gene Mutation (Mammalian) Data Gap (MRID 00083943 may be upgraded) 

870.5375 84-2B Structural Chromosomal 

Aberration 00088755 

870.5450 84-4 Other Genotoxic Effects Data Gap (MRID 00090008 may be upgraded) 

870.7485 85-1 General Metabolism 42540701 

OCCUPATIONAL/RESIDENTIAL EXPOSURE 

875.2100 132-1A Foliar Residue Dissipation Waived due to low toxicity 

47
Data Supporting Guideline Requirements for the Reregistration of Chlorsulfuron 

REQUIREMENT 

USE PATTERN CITATION(S) New Guideline Old Guideline Title Number Number 

875.2400 133-3 Dermal Passive Dosimetry 

Exposure 

875.2500 133-4 Inhalation Passive Dosimetry 

Exposure 

None 231 Estimation of Dermal Exposure 

at Outdoor Sites 

None 232 Estimation of Ihhalation 

Exposure at Outdoor Sites 

ENVIRONMENTAL FATE 

835.2120 161-1 Hydrolysis 

835.2240 161-2 Photodegradation - Water 

835.2410 161-3 Photodegradation - Soil 

835.4100 162-1 Aerobic Soil Metabolism 

835.4200 162-2 Anaerobic Soil Metabolism 

835.1240 163-1 Leaching/Adsorption/Desorption 

835.6100 164-1 Terrestrial Field Dissipation 

None 165-4 Bioaccumulation in Fish 

Waived due to low toxicity 

Waived due to low vapor pressure 

Satisfied by DuPont’s participation in the 

Spray Drift Taskforce 

Satisfied by DuPont’s participation in the 

Spray Drift Taskforce 

42156701 

42156702 

42156703 

42214201, 01130013 

01130024 

42146704 

42156705 

42214202 

41714401 

42214204 

48
Data Supporting Guideline Requirements for the Reregistration of Chlorsulfuron 

REQUIREMENT 

USE PATTERN CITATION(S) New Guideline Old Guideline Title Number Number 

RESIDUE CHEMISTRY 

860.1300 171-4A Nature of Residue - Plants 42248701, 43388402 

860.1300 171-4B Nature of Residue - Livestock 43600801, 43388401, 42248702, 43143501 

860.1340 171-4C Residue Analytical Method ­

Plants 

44218601, 44183501, 4418601, 44183501, 

43737701, 42900601, 42900602, 42948901, 

43747301 

860.1340 171-4D Residue Analytical Method ­

Animals 42926601, 43107801, 43833001 

860.1380 171-4E Storage Stability 44705401, 41976407, 42292501 

860.1500 171-4K Crop Field Trials 

(Wheat) 44705401, 43767301 

860.1520 171-4L Processed Food/Feed (Wheat) 42900601 

OTHER 

None None Plant toxicity from exposure to 

small droplets Data Gap 

850.3020 141-1 Honey Bee Acute Contact 42129902 

49 
Appendix C. TECHNICAL SUPPORT DOCUMENTS 

Additional documentation in support of this RED is maintained in the OPP docket, located in 

Room 119, Crystal Mall #2, 1801, South Bell Street, Arlington, VA. It is open Monday through 

Friday, excluding legal holidays, from 8:30 am to 4 pm. 

The docket initially contained preliminary risk assessments and related documents as of 

September 26, 2004. Sixty days later the first public comment period closed. The EPA then 

considered comments and revised the risk assessment. 

All documents and related addenda are available on the Agency's web page at 

www.epa.gov/pesticides and in the Public Docket at http://www.epa.gov/edocket under docket 

#OPP-2004-0219. 

These documents include: 

Documents supporting human health risk assessments: 

1. Hanley, Susan. Chlorsulfuron: Occupational and Residential Exposure and 

Risk Assessment/Characterization for Reregistration Eligibility Decision 

Document and the Proposed use on Pasture and Rangeland Grasses. July 

1, 2002. 

2. Fort, Felicia. Chlorsulfuron. Product Chemistry Chapter for the 

Reregistration Eligibility Decision. December 16, 2002. 

3. Taylor, Linda. Toxicology Chapter for CHLORSULFURON. July 17, 

2002. 

4. Taylor, Linda. CHLORSULFURON - Report of the Hazard Identification 

Assessment Review Committee. June 5, 2002. 

5. Taylor, Linda. CHLORSULFURON - Second Report of the Hazard 

Identification Assessment Review Committee. June 17, 2002. 

Documents supporting environmental fate and effects risk assessments: 

1. Balluff, Young and Kiernan. Environmental Fate and Ecological Risk 

Assessment for the Re-registration of Chlorsulfuron. May 10, 2005. 

2. Kiernan, Brian; Costello, Kevin. Response to Comments on the 

Environmental Fate and Ecological Risk Assessment of Chlorsulfuron. 

February 15, 2005. 

3. Kiernan, Brian; Costello, Kevin. Revised Environmental Fate and 

Ecological Risk Assessment of Chlorsulfuron. January 31, 2005. 

4. Birchfield, Norman; Costello, Kevin. Review of DuPont’s phase 1 “Error 

Correction” comments on the spray drift analysis for chlorsulfuron (MRID 

46128400). July 26, 2004. 

50
5. Birchfield, Norman. Revised assessment of risk to non-target plants 

associated with chlorsulfuron spray drift. July 27, 2004. 

Documents supporting use analysis: 

1. Scheltema, Christina. Use Closure Memo for Chlorsulfuron. February 13, 

2003. 

2. Zinn, Nicole; Kim, Jin. BEAD Review of Chlorsulfuron Comments. 

February 7, 2005. 

3. Zinn, Nicole; Kim, Jin. Addendum to Chlorsulfuron Benefits Discussion for 

Aerial Applications: Alternatives Analysis for Winter Wheat. May 2, 2005. 

51
Appendix D. CITATIONS CONSIDERED TO BE PART OF 

THE DATA BASE SUPPORTING 

REREGISTRATION DECISION 

(BIBLIOGRAPHY) 

GUIDE TO APPENDIX D 

1. CONTENTS OF BIBLIOGRAPHY. This bibliography contains citations of all studies 

considered relevant by EPA in arriving at the positions and conclusions stated elsewhere in the 

Reregistration Eligibility Document. Primary sources for studies in this bibliography have been 

the body of data submitted to EPA and its predecessor agencies in support of past regulatory 

decisions. Selections from other sources including the published literature, in those instances 

where they have been considered, are included. 

2. UNITS OF ENTRY. The unit of entry in this bibliography is called a "study". In the case of 

published materials, this corresponds closely to an article. In the case of unpublished materials 

submitted to the Agency, the Agency has sought to identify documents at a level parallel to the 

published article from within the typically larger volumes in which they were submitted. The 

resulting "studies" generally have a distinct title (or at least a single subject), can stand alone for 

purposes of review and can be described with a conventional bibliographic citation. The 

Agency has also attempted to unite basic documents and commentaries upon them, treating 

them as a single study. 

3. IDENTIFICATION OF ENTRIES. The entries in this bibliography are sorted numerically by 

Master Record Identifier, or "MRID” number. This number is unique to the citation, and should 

be used whenever a specific reference is required. It is not related to the six-digit "Accession 

Number" which has been used to identify volumes of submitted studies (see paragraph 4(d)(4) 

below for further explanation). In a few cases, entries added to the bibliography late in the 

review may be preceded by a nine character temporary identifier. These entries are listed after 

all MRID entries. This temporary identifying number is also to be used whenever specific 

reference is needed. 

4. FORM OF ENTRY. In addition to the Master Record Identifier (MRID), each entry consists 

of a citation containing standard elements followed, in the case of material submitted to EPA, by 

a description of the earliest known submission. Bibliographic conventions used reflect the 

standard of the American National Standards Institute (ANSI), expanded to provide for certain 

special needs. 

a Author. Whenever the author could confidently be identified, the Agency has chosen to 

show a personal author. When no individual was identified, the Agency has shown an 

identifiable laboratory or testing facility as the author. When no author or laboratory 

could be identified, the Agency has shown the first submitter as the author. 

b. Document date. The date of the study is taken directly from the document. When the 

date is followed by a question mark, the bibliographer has deduced the date from the 

52
evidence contained in the document. When the date appears as (1999), the Agency 

was unable to determine or estimate the date of the document. 

c. Title. In some cases, it has been necessary for the Agency bibliographers to create or 

enhance a document title. Any such editorial insertions are contained between square 

brackets. 

d. Trailing parentheses. For studies submitted to the Agency in the past, the trailing 

parentheses include (in addition to any self-explanatory text) the following elements 

describing the earliest known submission: 

(1) Submission date. The date of the earliest known submission appears 

immediately following the word "received." 

(2) Administrative number. The next element immediately following the word 

"under" is the registration number, experimental use permit number, petition 

number, or other administrative number associated with the earliest known 

submission. 

(3) Submitter. The third element is the submitter. When authorship is defaulted to 

the submitter, this element is omitted. 

(4) Volume Identification (Accession Numbers). The final element in the trailing 

parentheses identifies the EPA accession number of the volume in which the 

original submission of the study appears. The six-digit accession number 

follows the symbol "CDL," which stands for "Company Data Library." This 

accession number is in turn followed by an alphabetic suffix which shows the 

relative position of the study within the volume. 

53
______________________________________________________________________________ 

BIBLIOGRAPHY 

MRID CITATION 

00031406 Trivits, R.L. (1979) Oral LD50 Test in Fasted Male and Female Rats: Report No. 

399-79. (Unpublished study received Jun 16, 1980 under 352-EX-105; submitted by 

E.I. du Pont de Nemours & Co., Wil- mington, Del.; CDL:099460-A) 

00031414 Brittelli, M.R. (1976) Eye Irritation Test in Rabbits: Report No. 744-76. (Unpublished 

study received Jun 16, 1980 under 352- EX-105; submitted by E.I. du Pont de 

Nemours & Co., Wilmington, Del.; CDL:099460-I) 

00031417 Goodman, N.C. (1976) Primary Skin Irritation and Sensitization Tests on 

GuineaReport No. 794-76. (Unpublished study received Jun 16, 1980 under 

352-EX-105; submitted by E.I. du Pont de Nemours & Co., Wilmington, Del.; 

CDL:099460-L) 

00035262 Goodman, N.C. (1979) 48-Hour LC50 to~Daphnia magna~?: Haskell Lab- oratory 

Report No. 152-79. (Unpublished study received Jun 16, 1980 under 352-105; 

submitted by E.I. du Pont de Nemours & Co., Wilmington, Del.; CDL:099462-H) 

00035264 Hinkle, S.; Bristol, K.L. (1980) Final Report--Acute Oral LD50 Study in Mallard 

Ducks: Project No. 201-525. (Unpublished study received Jun 16, 1980 under 

352-105; prepared by Hazelton Labo- ratories America, Inc., submitted by E.I. du 

Pont de Nemours & Co., Wilmington, Del.; CDL:099462-J) 

00035265 Hinkle, S. (1979) Final Report--Avian Dietary Toxicity (LC50) Study in Bobwhite 

Quail: Project No. 201-523. (Unpublished study re- ceived Jun 16, 1980 under 

352-105; prepared by Hazleton Labora- tories America, Inc., submitted by E.I. du 

Pont de Nemours & Co., Wilmington, Del.; CDL:099462-K) 

00035266 Hinkle, S.; Wentz, K.L. (1979) Final Report--Avian Dietary Toxicity (LC50) in 

Mallard Ducks: Project No. 201-524. (Unpublished study received Jun 16, 1980 

under 352-105; prepared by Hazleton Laboratories America, Inc., submitted by E.I. 

du Pont de Nemours & Co., Wilmington, Del.; CDL:099462-L) 

00083956 Edwards, D.F. (1979) Acute Skin Absorption Test on Rabbits--LD50: Haskell 

Laboratory Report No. 415-79. (Unpublished study received Sep 1, 1981 under 

352-EX-109; submitted by E.I. du Pont de Nemours & Co., Wilmington, Del.; 

CDL:245879-I) 

54
______________________________________________________________________________ 

BIBLIOGRAPHY 

MRID CITATION 

00086825 Ferenz, R.L. (1980) LC50--inhalation Test for Pesticide Registration – AlbinoHaskell 

Laboratory Report No. 129-80. (Unpublished study received Nov 13, 1981 under 

352-404; sub- mitted by E.I. du Pont de Nemours & Co., Inc., Wilmington, Del.; 

CDL:070471-H) 

41714401 Dietrich, R.; Taylor, G. (1990) Field Soil Dissipation of {Phenyl 

(U)-(Carbonhlorsulfuron and {Triazine-2-(Carbon 14)} Chlosulfuron in Madera, 

California: Lab Project Number: AMR-1417-89: EF-89-03. Unpublished study 

prepared by E. I. du Pont de Nemours and Co. in Association with Pan-Agricultural 

Laboratories, Inc. 66 p. 

41976401 Ward, T.; Boeri, R. (1991) Static Acute Toxicity of DPX-W4189-165 (Chlorsulfuron) 

to the Sheepshead Minnow, Cyprindon variegatus: Lab Project Number: 

MR-4581-866: 516-91: 9130-DU. Unpublished study prepared by EnviroSystems 

Division. 31 p. 

41976402 Ward, T.; Boeri, R. (1991) Static Acute Toxicity of DPX-W4189-165 (Chlorsulfuron) 

to the Mysid, Mysidopsis bahia: Lab Project Number: MR-4581-866: 523-91: 

9131-DU. Unpublished study prepared by EnviroSystems Division. 31 p. 

41976403 Ward, T.; Boeri, R. (1991) Static Acute Toxicity of DPX-W4189-165 (Chlorsulfuron) 

to Bivalve Mollusc Embryos and Larvae: Lab Project Number: MR-4581-866: 

524-91: 9132-DU. Unpublished study prepared by EnviroSystems Division. 31 p. 

41976405 Pierson, K. (1991) Flow-Through 77 Day Toxicity of DPX-W4189-170 to Embryo 

and Larval Rainbow Trout, Oncorhynchus mykiss: Lab Project Number: 494-91: 

MR-4581-866. Unpublished study prepared by E.I. du Pont de Nemours and Co. 471 

p. 

41976408 Hutton, D. (1991) Chronic Toxicity of DPX-W4189-94 to Daphnia magna Lab 

Project Number: 4581-655: 87-89. Unpublished study prepared by E.I. du Pont de 

Nemours and Co. 92 p. 

42156701 Dietrich, R.; McAleer, N. (1989) Hydrolysis of ?Phenyl(U)-?carbon 14||Chlorsulfuron 

and ?Triazine-2-?carbon 14||Chlorsulfuron: Lab Project Number: 

AMR-1455-89.161-1. Unpublished study prepared by E.I. du Pont de Nemours & 

Co., Inc. 61 p. 

42156702 Dietrich, R.; McAleer, N. (1989) Photodegradation of ?Phenyl(U)-?carbon 

14||Chlorsulfuron and ?Triazine-2-?carbon 14||Chlorsulfuron in Water Conducted in 

55
______________________________________________________________________________ 

BIBLIOGRAPHY 

MRID CITATION 

Sunlight: Lab Project Number: AMR-1455-89. Unpublished study prepared by E.I. du 

Pont de Nemours & Co., Inc. 44 p. 

42156703 Hawkins, D.; Kirkpatrick, D.; Dean, G.; et al. (1990) The Photodegradation of 

?carbon 14|Chlorsulfuron on a Silty Clay Loam Soil: Lab Project Number: HRC/DPT 

205/90571: AMR-1563-89. Unpublished study prepared by Huntingdon Research 

Centre Ltd. 58 p. 

42156704 Chrzanowski, R.; Priester, T. (1991) Degradation of ?carbon 14|-DPX-W4189 in 

Anaerobic Aquatic Environments: Lab Project Number: AMR 38-91. Unpublished 

study prepared by E.I. du Pont de Nemours and Co. 45 p. 

42156705 Priester, T.; Sheftic, G. (1989) Batch Equilibrum (Adsorption/Desorption) with 

?carbon 14| Chlorsulfuron and Soil Thin-Layer Chromatograhphy Studies with ?carbon 

14|Chlorsulfuron and its Major Soil Degradates: Lab Project Number: AMR-1277-88. 

Unpublished study prepared by E. I. du Pont de Nemours & Co., Inc. 58 p. 

42186801 Blasberg, J.; Hicks, S.; Stratton, J. (1991) Acute Toxicity of Chlorsulfuron tostrum 

capricornutum Printz: Final Report: Lab Project Number: AMR-2081-91: 39427. 

Unpublished study prepared by ABC Laboratories, Inc. 33 p. 

42214201 Priester, T. (1991) Aerobic Soil Metabolism of Chlorsulfuron: Lab Project Number: 

AMR 2213-91. Unpublished study prepared by E.I. du Pont de Nemours and Co. 

305 p. 

42214202 Djanegara, T. (1991) Field Soil Dissipation Studies of Chlorsulfuron: Lab Project 

Number: AMR 2205-91. Unpublished study prepared by E. I. du Pont de Nemours & 

Co. 229 p. 

42214204 Priester, T. (1991) Fish Accumulation Potential for Chlorsulfuron: Lab Project Number: 

AMR 2238-91. Unpublished study prepared by E. I. du Pont de Nemours & Co. 61 

p. 

42328601 Ward, T.; Boeri, R. (1991) Static Acute Toxicity of DPX-W4189-165 (Chlorsulfuron) 

to Bivalve Mollusc Embryos and Larvae: Lab Project Number: 524-91: 

MR-4581-866. Unpublished study prepared by EnviroSystems Division, Resource 

Analysts, Inc. 31 p. 

56
______________________________________________________________________________ 

BIBLIOGRAPHY 

MRID CITATION 

42587201 McKelvey, R.; Kuratle, H. (1992) Influence of Chlorsulfuron on Seed Germination, 

Seedling Emergence, and Vegetative Vigor of Several Terrestrial Plants: Revision No. 

1: Lab Project Number: AMR 2070-91. Unpublished study prepared by E.I. du Pont 

de Nemours and Co. 235 p. 

42634001 Beavers, J.; Foster, J.; Lynn, S.; et al. (1992) H-18,053 (Chlorsulfuron): A 

One-generation Reproduction Study with the Northern Bobwhite (Colinus virginianus): 

Lab Project Number: 112-266: 564-92. Unpublished study prepared by Wildlife 

International Ltd. 185 p. 

42634002 Beavers, J.; Foster, J.; Lynn, S.; et al. (1992) H-18,053 (Chlorsulfuron): A 

One-Generation Reproduction Study with the Mallard (Anas platyrhynchos): Lab 

Project Number: 112-267: 565-92. Unpublished study prepared by Wildlife 

International Ltd. 185 p. 

45832901 Boeri, R.; Wyskiel, D.; Ward, T. (2002) Chlorsulfuron (DPX-W4189) Technical:nce 

on Growth Rate of the Duckweed, Lemna gibba: Lab Project Number: 2042-DU: 

DUPONT-4468: ASTM E1415-91. Unpublished study prepared by T.R. Wilbury 

Laboratories. 38 p. 

45832902 Boeri, R.; Wyskiel, D.; Ward, T. (2001) Chlorsulfuron (DPX-W4189) Technical:nce 

on Growth and Growth Rate of the Alga, Skeletonema costatum: Lab Project Number: 

2043-DU: DUPONT-4465. Unpublished study prepared by T.R. Wilbury 

Laboratories. 37 p. 

45832903 Boeri, R.; Wyskiel, D.; Ward, T. (2001) Chlorsulfuron (DPX-W4189) Technical:nce 

on Growth and Growth Rate of Alga, Anabaena flos-aquae: Lab Project Number: 

DUPONT-4466: 2044-DU. Unpublished study prepared by T.R. Wilbury 

Laboratories. 38 p. 

45832904 Boeri, R.; Wyskiel, D.; Ward, T. (2001) Chlorsulfuron (DPX-W4189) Technical:nce 

on Growth and Growth Rate of the Alga, Navicula pelliculosa: Lab Project Number: 

DUPONT-4467: 2045-DU. Unpublished study prepared by T.R. Wilbury 

Laboratories. 37 p. 

46326801 Porch, J.; Martin, K. (2004) Chlorsulfuron (DPX-W4189) 75WG: A Greenhouseto 

Investigate the Effects on Vegetative Vigor of Ten Terrestrial Plants Following Foliar 

Exposure. Project Number: 112/542, DUPONT/13552, 14901. Unpublished study 

prepared by Wildlife International, Ltd. 191 p. 

57
46361801 Porch, J.; Martin, K. (2004) Chlorsulfuron (DPX-W4189) 75WG: A Greenhouse to 

Investigate the Effects on Seedling Emergence and Growth of Ten Terrestrial Plants 

Following Soil Exposure. Project Number: 112/541, 14901, 1495. Unpublished study 

prepared by Wildlife International, Ltd. 264 p. 

58
Appendix E. GENERIC DATA CALL-IN 

A complete Data Call-In (DCI), with all pertinent instructions, is being sent to registrants under 

separate cover. 

59
Appendix F. PRODUCT SPECIFIC DATA CALL-IN 

See attached table for a list of product-specific data requirements. Note that a complete Data 

Call-In (DCI), with all pertinent instructions, is being sent to registrants under separate cover. 

60
D R A F T C O P Y Page 1 of 1 

INSTRUCTIONS: Please type or print in ink. Please read carefully the attached instructions and supply the information requested on this form. 

Use additional sheet(s) if necessary. 

1. Company Name and Address 

4. EPA Product 

Registration 

OMB Approval 2070-0107 

OMB Approval 2070-0057 

United States Environmental Protection Agency 

Washington, D.C. 20460 

DATA CALL-IN RESPONSE 

3. Date and Type of DCI and Number 

PRODUCT SPECIFIC 

ID # 

2. Case # and Name 

0631 Chlorsulfuron 

Chemical # and Name 118601 

Chlorsulfuron 

5. I wish to 

cancel this 

product registration voluntarily 

6. Generic Data 7. Product Specific Data 

7a. My product is an MUP and 

I agree to satisfy the MUP 

requirements on the attached 

form entitled "Requirements 

Status and Registrant's 

Response." 

7b. My product is an EUP and 

I agree to satisfy the EUP 

requirements on the attached 

form entitled "Requirements 

Status and Registrant's 

Response." 

6a. I am claiming a Generic 

Data Exemption because I 

obtain the active ingredient 

from the source EPA registration number listed below. 

6b. I agree to satisfy Generic 

Data requirements as indicated 

on the attached form entitled 

"Requirements Status and 

Registrant's Response." 

SAMPLE COMPANY 

NO STREET ADDRESS 

NO CITY, XX 00000 PDCI-118601-NNNN 

DD-MMM-YYYY 

NNNNNN-NNNNN N.A. N.A.

10. Name of Company 11. Phone Number 

8. Certification I certify that the statements made on this form and all attachments are true, accurate, and complete. I acknowledge that any 9. Date

knowingly false or misleading statement may be punishable by fine, imprisonment or both under applicable law. 

Signature and Title of Company's Authorized Representative__________________________________ 
D R A F T C O P Y Page 1 of 4 

INSTRUCTIONS: Please type or print in ink. Please read carefully the attached instructions and supply the information requested on this form. 

Use additional sheet(s) if necessary. 

4. Guideline 

Requirement 

Number 

5. Study Title 

1. Company Name and Address 

OMB Approval 2070-0107 

OMB Approval 2070-0057 

United States Environmental Protection Agency 

Washington, D.C. 20460 

REQUIREMENTS STATUS AND REGISTRANT'S RESPONSE 

3. Date and Type of DCI and Number 

ID # 

PRODUCT SPECIFIC 

2. Case # and Name 

0631 Chlorsulfuron 

EPA Reg. No. 

8. Time Frame 

(Months) 

9. Registrant 

Response 

7. Test 

Substance 

6. Use 

Pattern 

P 

R 

O 

T 

O 

C 

O 

L 

Progress 

Reports 

1 2 3

SAMPLE COMPANY 

NO STREET ADDRESS 

NO CITY, XX 00000 

DD-MMM-YYYY 

PDCI-118601-NNNN

NNNNNN-NNNNN 

Product Chemistry Data Requirements (Conventional 

Chemical) 

830.1550 (1) A, B, C, D, E, F, G, H, I, TGAI/MP/EP 8

J, K, L, M, N, O 

Product Identity and composition 

830.1600 (2) A, B, C, D, E, F, G, H, I, TGAI/MP/EP 8

J, K, L, M, N, O 

Description of materials used to produce the 

product 

830.1620 (3) A, B, C, D, E, F, G, H, I, TGAI 8

J, K, L, M, N, O 

Description of production process 

830.1650 (4) A, B, C, D, E, F, G, H, I, MP/EP 8

J, K, L, M, N, O 

Description of formulation process 

830.1670 (5) A, B, C, D, E, F, G, H, I, TGAI/MP/EP 8

J, K, L, M, N, O 

Discussion of formation of impurities 

830.1700 (6 ,7 ,8) A, B, C, D, E, F, G, H, I, TGAI 8

J, K, L, M, N, O 

Preliminary analysis 

830.1750 (9 ,10) A, B, C, D, E, F, G, H, I, TGAI/MP/EP 8

J, K, L, M, N, O 

Certified limits 

830.1800 (11) A, B, C, D, E, F, G, H, I, TGAI/MP/EP 8

J, K, L, M, N, O 

Enforcement analytical method 

830.6302 (12) A, B, C, D, E, F, G, H, I, TGAI/MP/EP 8

J, K, L, M, N, O 

Color 

12. Name of Company 13. Phone Number 

Signature and Title of Company's Authorized Representative__________________________________ 

10. Certification I certify that the statements made on this form and all attachments are true, accurate, and complete. I acknowledge that any 

knowingly false or misleading statement may be punishable by fine, imprisonment or both under applicable law 

11. Date 
D R A F T C O P Y Page 2 of 4 

United States Environmental Protection Agency 

Washington, D.C. 20460 

REQUIREMENTS STATUS AND REGISTRANT'S RESPONSE 

OMB Approval 2070-0107 

OMB Approval 2070-0057 

INSTRUCTIONS: Please type or print in ink. Please read carefully the attached instructions and supply the information requested on this form. 

Use additional sheet(s) if necessary. 

1. Company Name and Address 

SAMPLE COMPANY 

NO STREET ADDRESS 

NO CITY, XX 00000 

2. Case # and Name 

0631 Chlorsulfuron 

EPA Reg. No. NNNNNN-NNNNN 

3. Date and Type of DCI and Number 

ID # 

PRODUCT SPECIFIC 

DD-MMM-YYYY 

PDCI-118601-NNNN 

4. Guideline 

Requirement 

Number 

5. Study Title P 

R 

O 

T 

O 

C 

O 

L 

Progress 

Reports 

6. Use 

Pattern 

7. Test 

Substance 

8. Time Frame 

(Months) 

9. Registrant 

Response 

1 2 3 

830.6303 

830.6304 

830.6313 

830.6314 

830.6315 

830.6316 

830.6317 

830.6319 

830.6320 

830.6321 

Physical state (13)

Odor (14)

Stability to sunlight, normal and elevated (15 ,16)

temperatures, metals, and metal ions 

Oxidizing or reducing action (17)

Flammability (18)

Explodability (19)

Storage stability of product (20)

Miscibility (21)

Corrosion characteristics (22)

Dielectric breakdown voltage (23)

A, B, C, D, E, F, G, H, I, 

J, K, L, M, N, O 

A, B, C, D, E, F, G, H, I, 

J, K, L, M, N, O 

A, B, C, D, E, F, G, H, I, 

J, K, L, M, N, O 

A, B, C, D, E, F, G, H, I, 

J, K, L, M, N, O 

A, B, C, D, E, F, G, H, I, 

J, K, L, M, N, O 

A, B, C, D, E, F, G, H, I, 

J, K, L, M, N, O 

A, B, C, D, E, F, G, H, I, 

J, K, L, M, N, O 

A, B, C, D, E, F, G, H, I, 

J, K, L, M, N, O 

A, B, C, D, E, F, G, H, I, 

J, K, L, M, N, O 

A, B, C, D, E, F, G, H, I, 

J, K, L, M, N, O 

TGAI/MP/EP 

TGAI/MP/EP 

TGAI 

MP/EP 

MP/EP 

MP/EP 

MP/EP 

MP/EP 

MP/EP 

MP/EP 

8 

8 

8 

8 

8 

8 

8 

8 

8 

8 

Initial to indicate certification 

(full text of certification is on

as to information on this page 

page one).

Date 
D R A F T C O P Y Page 3 of 4 

United States Environmental Protection Agency 

Washington, D.C. 20460 

REQUIREMENTS STATUS AND REGISTRANT'S RESPONSE 

OMB Approval 2070-0107 

OMB Approval 2070-0057 

INSTRUCTIONS: Please type or print in ink. Please read carefully the attached instructions and supply the information requested on this form. 

Use additional sheet(s) if necessary. 

1. Company Name and Address 

SAMPLE COMPANY 

NO STREET ADDRESS 

NO CITY, XX 00000 

2. Case # and Name 

0631 Chlorsulfuron 

EPA Reg. No. NNNNNN-NNNNN 

3. Date and Type of DCI and Number 

ID # 

PRODUCT SPECIFIC 

DD-MMM-YYYY 

PDCI-118601-NNNN 

4. Guideline 

Requirement 

Number 

5. Study Title P 

R 

O 

T 

O 

C 

O 

L 

Progress 

Reports 

6. Use 

Pattern 

7. Test 

Substance 

8. Time Frame 

(Months) 

9. Registrant 

Response 

1 2 3 

830.7000 

830.7050 

830.7100 

830.7200 

830.7220 

830.7300 

830.7370 

830.7550 

830.7570 

830.7840 

pH of water solutions or suspensions (24 ,25)

UV/Visible absorption 

Viscosity (26)

Melting point/melting range (27 ,28)

Boiling point/boiling range (29 ,30)

Density/relative density (31 ,32)

Dissociation constant in water (33 ,34)

Partition coefficient (n-octanol/water), shake flask (35)

method 

Partition coefficient (n-octanol/water), estimation by (36)

liquid chromatography 

Water solubility: Column elution method, shake flask (37)

method 

A, B, C, D, E, F, G, H, I, 

J, K, L, M, N, O 

A, B, C, D, E, F, G, H, I, 

J, K, L, M, N, O 

A, B, C, D, E, F, G, H, I, 

J, K, L, M, N, O 

A, B, C, D, E, F, G, H, I, 

J, K, L, M, N, O 

A, B, C, D, E, F, G, H, I, 

J, K, L, M, N, O 

A, B, C, D, E, F, G, H, I, 

J, K, L, M, N, O 

A, B, C, D, E, F, G, H, I, 

J, K, L, M, N, O 

A, B, C, D, E, F, G, H, I, 

J, K, L, M, N, O 

A, B, C, D, E, F, G, H, I, 

J, K, L, M, N, O 

A, B, C, D, E, F, G, H, I, 

J, K, L, M, N, O 

TGAI/MP/EP 

TGAI/PAI 

MP/EP 

TGAI 

TGAI 

TGAI/MP/EP 

TGAI or PAI 

TGAI/PAI 

TGAI/PAI 

TGAI or PAI 

8 

8 

8 

8 

8 

8 

8 

8 

8 

8 

Initial to indicate certification 

(full text of certification is on

as to information on this page 

page one).

Date 
D R A F T C O P Y Page 4 of 4 

United States Environmental Protection Agency 

Washington, D.C. 20460 

REQUIREMENTS STATUS AND REGISTRANT'S RESPONSE 

OMB Approval 2070-0107 

OMB Approval 2070-0057 

INSTRUCTIONS: Please type or print in ink. Please read carefully the attached instructions and supply the information requested on this form. 

Use additional sheet(s) if necessary. 

1. Company Name and Address 

SAMPLE COMPANY 

NO STREET ADDRESS 

NO CITY, XX 00000 

2. Case # and Name 

0631 Chlorsulfuron 

EPA Reg. No. NNNNNN-NNNNN 

3. Date and Type of DCI and Number 

ID # 

PRODUCT SPECIFIC 

DD-MMM-YYYY 

PDCI-118601-NNNN 

4. Guideline 

Requirement 

Number 

5. Study Title P 

R 

O 

T 

O 

C 

O 

L 

Progress 

Reports 

6. Use 

Pattern 

7. Test 

Substance 

8. Time Frame 

(Months) 

9. Registrant 

Response 

1 2 3 

830.7860 

830.7950 

870.1100 

870.1200 

870.1300 

870.2400 

870.2500 

870.2600 

Water solubility, generator column method (38)

Vapor pressure (39 ,40)

Toxicology Data Requirements (Conventional Chemical) 

Acute Oral Toxicity (41)

Acute dermal toxicity (42 ,43)

Acute inhalation toxicity (44)

Acute eye irritation (45)

Acute dermal irritation (46 ,47)

Skin sensitization (48 ,49)

A, B, C, D, E, F, G, H, I, 

J, K, L, M, N, O 

A, B, C, D, E, F, G, H, I, 

J, K, L, M, N, O 

A, B, C, D, E, F, G, H, I, 

J, K, L, M, N, O 

A, B, C, D, E, F, G, H, I, 

J, K, L, M, N, O 

A, B, C, D, E, F, G, H, I, 

J, K, L, M, N, O 

A, B, C, D, E, F, G, H, I, 

J, K, L, M, N, O 

A, B, C, D, E, F, G, H, I, 

J, K, L, M, N, O 

A, B, C, D, E, F, G, H, I, 

J, K, L, M, N, O 

TGAI or PAI 

TGAI or PAI 

TGAI,EP,dilute EP? 

TGAI,EP,dilute EP? 

TGAI & EP 

TGAI & EP 

TGAI & EP 

TGAI & EP 

8 

8 

8 

8 

8 

8 

8 

8 

Initial to indicate certification 

(full text of certification is on

as to information on this page 

page one).

Date 
D R A F T C O P Y Page 1 of 9 

United States Environmental Protection Agency 

Washington, D.C. 20460 

FOOTNOTES AND KEY DEFINITIONS FOR GUIDELINE REQUIREMENTS 

Case # and Name: 0631 Chlorsulfuron 

DCI Number: PDCI-118601-NNNN 

Key: MP/EP = Manufacturing-Use Product, Pure Active Ingredient; TGAI = Technical Grade Active Ingredient [TGAI]; TGAI & EP = Technical Grade of the Active Ingredient and End-Use Product; TGAI or 

PAI = Technical Grade of the Active Ingredient or Pure Active Ingredient; TGAI,EP,dilute EP? = Technical Grade of the Active Ingredient, End Use Product, and possibly diluted End Use Product; 

TGAI/MP/EP = Manufacturing-Use Product, Pure Active Ingredient and Technical Grade Active Ingredient; TGAI/PAI = Technical Grade Active Ingredient, Pure Active Ingredient 

Use Categories Key: 

A - Terrestrial food crop D - Aquatic food crop G - Aquatic non-food residential J - Forestry use M - Indoor nonfood use 

B - Terrestrial feed crop E - Aquatic nonfood outdoor use H - Greenhouse food crop K - Residential N - Indoor medical use 

C - Terrestrial nonfood crop F - Aquatic nonfood industrial use I - Greenhouse nonfood crop L - Indoor food use O - Residential Indoor use 

Footnotes: [The following notes are referenced in column two (5. Study File) of the REQUIREMENTS STATUS AND REGISTRANT'S RESPONSE form.] 

1 Data must be provided in accordance with the "Product Composition" Section.(158.155) 

2 Data must be provided in accordance with the "Description of Materials used to Produce the Product" Section.(158.160) 

3 Data must be provided in accordance with the "Description of Production Process" Section.(158.162) 

4 Data must be provided in accordance with the "Description of Formulation Process" Section.(158.165) 

5 Data must be provided in accordance with the "Description of Formation of Impurities" Section(158.167) 

6 Data must be provided in accordance with the "Preliminary Analysis" Section.(158.170) 
D R A F T C O P Y Page 2 of 9 

United States Environmental Protection Agency 

Washington, D.C. 20460 

FOOTNOTES AND KEY DEFINITIONS FOR GUIDELINE REQUIREMENTS 

Case # and Name: 0631 Chlorsulfuron 

DCI Number: PDCI-118601-NNNN 

Key: MP/EP = Manufacturing-Use Product, Pure Active Ingredient; TGAI = Technical Grade Active Ingredient [TGAI]; TGAI & EP = Technical Grade of the Active Ingredient and End-Use Product; TGAI or 

PAI = Technical Grade of the Active Ingredient or Pure Active Ingredient; TGAI,EP,dilute EP? = Technical Grade of the Active Ingredient, End Use Product, and possibly diluted End Use Product; 

TGAI/MP/EP = Manufacturing-Use Product, Pure Active Ingredient and Technical Grade Active Ingredient; TGAI/PAI = Technical Grade Active Ingredient, Pure Active Ingredient 

Footnotes: [The following notes are referenced in column two (5. Study File) of the REQUIREMENTS STATUS AND REGISTRANT'S RESPONSE form.] 

7 Required for TGAIs and products produced by an integrated system. 

8 If the TGAI cannot be isolated, data are required on the practical equivalent of the TGAI (i.e., if the active ingredient is either an acid, base or ionic form, and it is formulated into salts or 

esters, the concentration of the active ingredient in these products must be expressed in acid equivalent or active equivalent). 

9 Data must be provided in accordance with the "Certified Limits" Section(158.175) 

10 If the TGAI cannot be isolated, data are required on the practical equivalent of the TGAI (i.e., if the active ingredient is either an acid, base or ionic form, and it is formulated into salts or 

esters, the concentration of the active ingredient in these products must be expressed in acid equivalent or active equivalent). 

11 Data must be provided in accordance with the "Enforcement Analytical Method" Section.(158.180) 

12 If the TGAI cannot be isolated, data are required on the practical equivalent of the TGAI (i.e., if the active ingredient is either an acid, base or ionic form, and it is formulated into salts or 

esters, the concentration of the active ingredient in these products must be expressed in acid equivalent or active equivalent). 
D R A F T C O P Y Page 3 of 9 

United States Environmental Protection Agency 

Washington, D.C. 20460 

FOOTNOTES AND KEY DEFINITIONS FOR GUIDELINE REQUIREMENTS 

Case # and Name: 0631 Chlorsulfuron 

DCI Number: PDCI-118601-NNNN 

Key: MP/EP = Manufacturing-Use Product, Pure Active Ingredient; TGAI = Technical Grade Active Ingredient [TGAI]; TGAI & EP = Technical Grade of the Active Ingredient and End-Use Product; TGAI or 

PAI = Technical Grade of the Active Ingredient or Pure Active Ingredient; TGAI,EP,dilute EP? = Technical Grade of the Active Ingredient, End Use Product, and possibly diluted End Use Product; 

TGAI/MP/EP = Manufacturing-Use Product, Pure Active Ingredient and Technical Grade Active Ingredient; TGAI/PAI = Technical Grade Active Ingredient, Pure Active Ingredient 

Footnotes: [The following notes are referenced in column two (5. Study File) of the REQUIREMENTS STATUS AND REGISTRANT'S RESPONSE form.] 

13 If the TGAI cannot be isolated, data are required on the practical equivalent of the TGAI (i.e., if the active ingredient is either an acid, base or ionic form, and it is formulated into salts or 

esters, the concentration of the active ingredient in these products must be expressed in acid equivalent or active equivalent). 

14 If the TGAI cannot be isolated, data are required on the practical equivalent of the TGAI (i.e., if the active ingredient is either an acid, base or ionic form, and it is formulated into salts or 

esters, the concentration of the active ingredient in these products must be expressed in acid equivalent or active equivalent). 

15 If the TGAI cannot be isolated, data are required on the practical equivalent of the TGAI (i.e., if the active ingredient is either an acid, base or ionic form, and it is formulated into salts or 

esters, the concentration of the active ingredient in these products must be expressed in acid equivalent or active equivalent). 

16 Data on the stability to metals and metal ions is required only if the active ingredient is expected to come in contact with either material during storage. 

17 Required if the product contains an oxidizing or reducing agent 

18 Required when the product contains combustible liquids. 
D R A F T C O P Y Page 4 of 9 

United States Environmental Protection Agency 

Washington, D.C. 20460 

FOOTNOTES AND KEY DEFINITIONS FOR GUIDELINE REQUIREMENTS 

Case # and Name: 0631 Chlorsulfuron 

DCI Number: PDCI-118601-NNNN 

Key: MP/EP = Manufacturing-Use Product, Pure Active Ingredient; TGAI = Technical Grade Active Ingredient [TGAI]; TGAI & EP = Technical Grade of the Active Ingredient and End-Use Product; TGAI or 

PAI = Technical Grade of the Active Ingredient or Pure Active Ingredient; TGAI,EP,dilute EP? = Technical Grade of the Active Ingredient, End Use Product, and possibly diluted End Use Product; 

TGAI/MP/EP = Manufacturing-Use Product, Pure Active Ingredient and Technical Grade Active Ingredient; TGAI/PAI = Technical Grade Active Ingredient, Pure Active Ingredient 

Footnotes: [The following notes are referenced in column two (5. Study File) of the REQUIREMENTS STATUS AND REGISTRANT'S RESPONSE form.] 

19 Required when the product is potentially explosive. 

20 Please see attached "Additional Information and Requirements Pertaining to Storage Stability (OPPTS 830.6317) and Corrosion Characteristics (OPPTS 830.6320) Data Requirements of the 

Product Specific Data Call-Ins issued under the Reregistration Eligibility Decision (RED)/Interim Reregistration Eligibility Decision (IRED) Documents." 

21 Required if the product is an emulsifiable liquid and is to be diluted with petroleum solvents. 

22 Please see attached "Additional Information and Requirements Pertaining to Storage Stability (OPPTS 830.6317) and Corrosion Characteristics (OPPTS 830.6320) Data Requirements of the 

Product Specific Data Call-Ins issued under the Reregistration Eligibility Decision (RED)/Interim Reregistration Eligibility Decision (IRED) Documents." 

23 Required if the end-use product is a liquid and is to be used around electrical equipment. 

24 If the TGAI cannot be isolated, data are required on the practical equivalent of the TGAI (i.e., if the active ingredient is either an acid, base or ionic form, and it is formulated into salts or 

esters, the concentration of the active ingredient in these products must be expressed in acid equivalent or active equivalent). 
D R A F T C O P Y Page 5 of 9 

United States Environmental Protection Agency 

Washington, D.C. 20460 

FOOTNOTES AND KEY DEFINITIONS FOR GUIDELINE REQUIREMENTS 

Case # and Name: 0631 Chlorsulfuron 

DCI Number: PDCI-118601-NNNN 

Key: MP/EP = Manufacturing-Use Product, Pure Active Ingredient; TGAI = Technical Grade Active Ingredient [TGAI]; TGAI & EP = Technical Grade of the Active Ingredient and End-Use Product; TGAI or 

PAI = Technical Grade of the Active Ingredient or Pure Active Ingredient; TGAI,EP,dilute EP? = Technical Grade of the Active Ingredient, End Use Product, and possibly diluted End Use Product; 

TGAI/MP/EP = Manufacturing-Use Product, Pure Active Ingredient and Technical Grade Active Ingredient; TGAI/PAI = Technical Grade Active Ingredient, Pure Active Ingredient 

Footnotes: [The following notes are referenced in column two (5. Study File) of the REQUIREMENTS STATUS AND REGISTRANT'S RESPONSE form.] 

25 Required if the product is dispersible with water. 

26 Required if the product is a liquid. 

27 If the TGAI cannot be isolated, data are required on the practical equivalent of the TGAI (i.e., if the active ingredient is either an acid, base or ionic form, and it is formulated into salts or 

esters, the concentration of the active ingredient in these products must be expressed in acid equivalent or active equivalent). 

28 Required when the TGAI is solid at room temperature. 

29 If the TGAI cannot be isolated, data are required on the practical equivalent of the TGAI (i.e., if the active ingredient is either an acid, base or ionic form, and it is formulated into salts or 

esters, the concentration of the active ingredient in these products must be expressed in acid equivalent or active equivalent). 

30 Required if the TGAI is liquid at room temperature. 
D R A F T C O P Y Page 6 of 9 

United States Environmental Protection Agency 

Washington, D.C. 20460 

FOOTNOTES AND KEY DEFINITIONS FOR GUIDELINE REQUIREMENTS 

Case # and Name: 0631 Chlorsulfuron 

DCI Number: PDCI-118601-NNNN 

Key: MP/EP = Manufacturing-Use Product, Pure Active Ingredient; TGAI = Technical Grade Active Ingredient [TGAI]; TGAI & EP = Technical Grade of the Active Ingredient and End-Use Product; TGAI or 

PAI = Technical Grade of the Active Ingredient or Pure Active Ingredient; TGAI,EP,dilute EP? = Technical Grade of the Active Ingredient, End Use Product, and possibly diluted End Use Product; 

TGAI/MP/EP = Manufacturing-Use Product, Pure Active Ingredient and Technical Grade Active Ingredient; TGAI/PAI = Technical Grade Active Ingredient, Pure Active Ingredient 

Footnotes: [The following notes are referenced in column two (5. Study File) of the REQUIREMENTS STATUS AND REGISTRANT'S RESPONSE form.] 

31 If the TGAI cannot be isolated, data are required on the practical equivalent of the TGAI (i.e., if the active ingredient is either an acid, base or ionic form, and it is formulated into salts or 

esters, the concentration of the active ingredient in these products must be expressed in acid equivalent or active equivalent). 

32 True density or specific density are required for all test substances. Data on bulk density is required for MPs that are solid at room temperature. 

33 If the TGAI cannot be isolated, data are required on the practical equivalent of the TGAI (i.e., if the active ingredient is either an acid, base or ionic form, and it is formulated into salts or 

esters, the concentration of the active ingredient in these products must be expressed in acid equivalent or active equivalent). 

34 Required when the test substance contains an acid or base functionality (organic or inorganic) or an alcoholic functionality (organic). 

35 Required if the TGAI or PAI is organic and non-polar. 

36 Required if the TGAI or PAI is organic and non-polar. 
D R A F T C O P Y Page 7 of 9 

United States Environmental Protection Agency 

Washington, D.C. 20460 

FOOTNOTES AND KEY DEFINITIONS FOR GUIDELINE REQUIREMENTS 

Case # and Name: 0631 Chlorsulfuron 

DCI Number: PDCI-118601-NNNN 

Key: MP/EP = Manufacturing-Use Product, Pure Active Ingredient; TGAI = Technical Grade Active Ingredient [TGAI]; TGAI & EP = Technical Grade of the Active Ingredient and End-Use Product; TGAI or 

PAI = Technical Grade of the Active Ingredient or Pure Active Ingredient; TGAI,EP,dilute EP? = Technical Grade of the Active Ingredient, End Use Product, and possibly diluted End Use Product; 

TGAI/MP/EP = Manufacturing-Use Product, Pure Active Ingredient and Technical Grade Active Ingredient; TGAI/PAI = Technical Grade Active Ingredient, Pure Active Ingredient 

Footnotes: [The following notes are referenced in column two (5. Study File) of the REQUIREMENTS STATUS AND REGISTRANT'S RESPONSE form.] 

37 If the TGAI cannot be isolated, data are required on the practical equivalent of the TGAI (i.e., if the active ingredient is either an acid, base or ionic form, and it is formulated into salts or 

esters, the concentration of the active ingredient in these products must be expressed in acid equivalent or active equivalent). 

38 If the TGAI cannot be isolated, data are required on the practical equivalent of the TGAI (i.e., if the active ingredient is either an acid, base or ionic form, and it is formulated into salts or 

esters, the concentration of the active ingredient in these products must be expressed in acid equivalent or active equivalent). 

39 If the TGAI cannot be isolated, data are required on the practical equivalent of the TGAI (i.e., if the active ingredient is either an acid, base or ionic form, and it is formulated into salts or 

esters, the concentration of the active ingredient in these products must be expressed in acid equivalent or active equivalent). 

40 Not required for salts. 

41 Not required if test material is a gas or a highly volatile liquid. 

42 Not required if test material is a gas or a highly volatile liquid. 
D R A F T C O P Y Page 8 of 9 

United States Environmental Protection Agency 

Washington, D.C. 20460 

FOOTNOTES AND KEY DEFINITIONS FOR GUIDELINE REQUIREMENTS 

Case # and Name: 0631 Chlorsulfuron 

DCI Number: PDCI-118601-NNNN 

Key: MP/EP = Manufacturing-Use Product, Pure Active Ingredient; TGAI = Technical Grade Active Ingredient [TGAI]; TGAI & EP = Technical Grade of the Active Ingredient and End-Use Product; TGAI or 

PAI = Technical Grade of the Active Ingredient or Pure Active Ingredient; TGAI,EP,dilute EP? = Technical Grade of the Active Ingredient, End Use Product, and possibly diluted End Use Product; 

TGAI/MP/EP = Manufacturing-Use Product, Pure Active Ingredient and Technical Grade Active Ingredient; TGAI/PAI = Technical Grade Active Ingredient, Pure Active Ingredient 

Use Categories Key: 

A - Terrestrial food crop D - Aquatic food crop G - Aquatic non-food residential J - Forestry use M - Indoor nonfood use 

B - Terrestrial feed crop E - Aquatic nonfood outdoor use H - Greenhouse food crop K - Residential N - Indoor medical use 

C - Terrestrial nonfood crop F - Aquatic nonfood industrial use I - Greenhouse nonfood crop L - Indoor food use O - Residential Indoor use 

Footnotes: [The following notes are referenced in column two (5. Study File) of the REQUIREMENTS STATUS AND REGISTRANT'S RESPONSE form.] 

43 Not required if test material is corrosive to skin or has a pH of less than 2 or greater than 11.5. 

44 Required if the product consists of, or under conditions of use will result in, a respirable material (e.g., gas, vapor, aerosol, or particulate). 

45 Not required if test material is corrosive to skin or has a pH of less than 2 or greater than 11.5. 

46 Not required if test material is a gas or a highly volatile liquid. 

47 Not required if test material is corrosive to skin or has a pH of less than 2 or greater than 11.5. 

48 Not required if test material is corrosive to skin or has a pH of less than 2 or greater than 11.5. 
49 

D R A F T C O P Y Page 9 of 9 

United States Environmental Protection Agency 

Washington, D.C. 20460 

FOOTNOTES AND KEY DEFINITIONS FOR GUIDELINE REQUIREMENTS 

Case # and Name: 0631 Chlorsulfuron 

DCI Number: PDCI-118601-NNNN 

Key: MP/EP = Manufacturing-Use Product, Pure Active Ingredient; TGAI = Technical Grade Active Ingredient [TGAI]; TGAI & EP = Technical Grade of the Active Ingredient and End-Use Product; TGAI or 

PAI = Technical Grade of the Active Ingredient or Pure Active Ingredient; TGAI,EP,dilute EP? = Technical Grade of the Active Ingredient, End Use Product, and possibly diluted End Use Product; 

TGAI/MP/EP = Manufacturing-Use Product, Pure Active Ingredient and Technical Grade Active Ingredient; TGAI/PAI = Technical Grade Active Ingredient, Pure Active Ingredient 

Footnotes: [The following notes are referenced in column two (5. Study File) of the REQUIREMENTS STATUS AND REGISTRANT'S RESPONSE form.] 

Required if repeated dermal exposure is likely to occur under conditions of use. 
United States Environmental Protection Agency 

Washington, D.C. 20460 

LIST OF ALL REGISTRANTS SENT THIS DATA CALL-IN NOTICE 

Co. Nr. Company Name Agent For Address City & State Zip 

Case # and Name: 0631,Chlorsulfuron 

228 NUFARM AMERICAS INC. 1333 BURR RIDGE PARKWAY, SUITE 125A BURR RIDGE IL 605270866 

352 E. I. DU PONT DE NEMOURS AND PO Box 30 STINE-HASKELL RESEARCH NEWARK DE 197140030 

CO., INC. CENTER/1090 ELKTON RD 

10404 LESCO INC 1301 EAST 9TH STREET, SUITE 1300 CLEVELAND OH 441141849 
Appendix G. EPA’S BATCHING OF CHLORSULFURON PRODUCTS FOR MEETING 

ACUTE TOXICITY DATA REQUIREMENTS FOR REREGISTRATION 

In an effort to reduce the time, resources and number of animals needed to fulfill the acute 

toxicity data requirements for reregistration of products containing chlorsulfuron as the active ingredient, 

the Agency has batched products which can be considered similar for purposes of acute toxicity. 

Factors considered in the sorting process include each product’s active and inert ingredients (e.g., 

identity, percent composition and biological activity), type of formulation (e.g., emulsifiable concentrate, 

aerosol, wettable powder, granular), and labeling (e.g., signal word, use classification, precautionary 

labeling.). Note that the Agency is not describing batched products as "substantially similar" since some 

products within a batch may not be considered chemically similar or have identical use patterns. 

Using available information, batching has been accomplished by the process described in the 

preceding paragraph. Notwithstanding the batching process, the Agency reserves the right to require, 

at any time, acute toxicity data for an individual product should the need arise. 

Registrants of products within a batch may choose to cooperatively generate, submit or cite a 

single battery of six acute toxicological studies to represent all the products within that batch. It is the 

registrants’ option to participate in the process with all other registrants, only some of the other 

registrants, or only their own products within a batch, or to generate all the required acute toxicological 

studies for each of their own products. If a registrant chooses to generate the data for a batch, he/she 

must use one of the products within the batch as the test material. If a registrant chooses to rely upon 

previously submitted acute toxicity data, he/she may do so provided that the data base is complete and 

valid by today's standards (see acceptance criteria attached), the formulation tested is considered by 

EPA to be similar for acute toxicity, and the formulation has not been significantly altered since 

submission and acceptance of the acute toxicity data. Regardless of whether new data is generated or 

existing data is referenced, registrants must clearly identify the test material by the EPA Registration 

Number. If more than one confidential statement of formula (CSF) exists for a product, the registrant 

must indicate the formulation actually tested by identifying the corresponding CSF. 

In deciding how to meet the product specific data requirements, registrants must follow the 

directions given in the Data Call-In notice (DCI) and its attachments appended to the RED. The DCI 

notice contains two response forms which are to be completed and submitted to the Agency within 90 

days of receipt. The first form, “Data Call-In Response” asks whether the registrant will meet the data 

requirements for each product. The second form, “Requirements Status and Registrant's Response” 

lists the product specific data required for each product, including the standard six acute toxicity tests. 

A registrant who wishes to participate in a batch must decide whether he/she will provide the data or 

depend on someone else to do so. If a registrant supplies the data to support a batch of products, 

he/she must select one of the following options: Developing Data (Option 1), Submitting an Existing 

Study (Option 4), Upgrading an Existing Study (Option 5) or Citing an Existing Study (Option 6). If a 

registrant depends on another's data, he/she must choose among: Cost Sharing (Option 2), Offers to 

Cost Share (Option 3) or Citing an Existing Study (Option 6). If a registrant does not want to 

participate in a batch, the choices are Options 1, 4, 5 or 6. However, a registrant should know that 

choosing not to participate in a batch does not preclude other registrants in the batch from citing his/her 

studies and offering to cost share (Option 3) those studies. 

61
Eight products were found which contain chlorsulfuron as the active ingredient. These products 

have been placed into two batches and a "no batch" category in accordance with the active and inert 

ingredients and type of formulation. The batching for these products is contained in the following table. 

Batch 

Number EPA Reg. No. % Active Ingredient 

1 

228-375 75.0 

352-522 75.0 

2 

352-404 75.0 

10404-59 75.0 

352-516 98.00 

352-445 Chlorsulfuron: 62.50 

Metasulfuron: 12.50 

No Batch 

352-620 Chlorsulfuron: 18.75 

Sulfometuron methyl: 56.25 

352-621 Chlorsulfuron: 25.00 

Sulfometuron methyl: 50.00 

NOTE: The technical acute toxicity values included in this document are for informational purposes 

only. The data supporting these values may or may not meet the current acceptance criteria. 

62