Page 2 of 30

Executive Summary

The HED Registration Review Team has evaluated human health assessments for the herbicide 

halosulfuron-methyl to determine whether sufficient data are available and whether any updates 

are needed to support Registration Review. HED has considered the most recent human-health

risk assessments for halosulfuron-methyl, updates to the toxicity, exposure, and usage databases, 

and current Agency science policy and risk assessment methodologies to determine the scope of 

work necessary to support Registration Review. In addition, HED conducted an open literature 

search to look for new literature relevant to the human health risk assessment and found no 

relevant toxicity or exposure information. 

Halosulfuron-methyl, a sulfonylurea herbicide, inhibits the action of the plant enzyme 

acetolactate synthase. Halosulfuron-methyl has low acute toxicity. With repeated dosing, 

halosulfuron produces non-specific effects, which are frequently characterized by reduced body 

weight/body weight gain in the test animals. Halosulfuron-methyl is classified as “not likely to 

be carcinogenic to humans.” It is negative for mutagenicity in a battery of genotoxicity studies. 

The FQPA safety factor is 1X. Although the data indicated an increase in qualitative 

susceptibility in fetuses following prenatal exposure in rats and rabbits, the developmental 

effects were seen in the presence of maternal effects and clear NOAELs and LOAELs were 

established for both maternal and developmental effects. In addition, the developmental effects 

in rats were seen at doses approaching the limit dose (1000 mg/kg). It was concluded that the 

degree of concern was low and there was no residual uncertainty in either the rat or rabbit 

developmental toxicity study. In addition to a lack of residual concerns for susceptibility, there 

was no evidence of neurotoxicity, and exposures were not considered to be underestimated. The 

toxicology database is adequate, with the exception of the requirement for an immunotoxicity 

study. This study was required as a condition of registration. The 28-day inhalation toxicity 

study, also a condition of registration, was waived (Hazard and Science Policy Council 

(HASPOC) Meeting, TXR # 0054045, DP# D397243, D. Smegal, MPH, 2/22/12).

In addition to the agricultural food uses, halosulfuron-methyl is also registered for use on 

turfgrass, ornamentals, and a variety of non-crop areas including, but not limited to, airports, 

cemeteries, fallow non-crop areas, golf courses, landscaped areas, public recreation areas, 

residential property, roadsides, school grounds, sod or turf seed farms, sports fields, residential 

and commercial landscaped areas with established woody ornamentals, fairgrounds, race tracks, 

tennis courts, campgrounds, and rights-of-way.

All residential (turfgrass and ornamentals) and occupational exposure scenarios were not 

assessed based on current policies. Also, residential and occupational assessments for the higher 

registered application rate of 0.14 lb ai/A (based on label EPA Reg. No. 81880-24) have never 

been conducted. In addition, the highest application rate for field corn on one label (EPA Reg. 

No. 81880-20) has not been assessed and is the result of a typographical error. However, on 

February 28, 2012, the registrant requested the voluntary cancellation of this product, and the 

Agency will process this cancellation through the Federal Register. In light of the pending 

cancellation, this rate will not need to be assessed in registration review. 
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A new comprehensive human health risk assessment is not expected to be needed during 

registration review, unless the results of the immunotoxicity study or changes in science and 

policy result in changes to toxicological endpoints. Specifically, in addition, HED anticipates 

conducting a new risk assessment in July 2012 in conjunction with proposed new halosulfuron 

uses/tolerances under PRIA; this new assessment will entail new dietary and aggregate 

assessments and an occupational assessment of the proposed new uses. 

Introduction

Halosulfuron-methyl is a selective herbicide belonging to the sulfonylurea group of herbicides. 

It inhibits the action of the plant enzyme acetolactate synthase. The enzyme is not found in 

mammals (including humans). Halosulfuron-methyl is used for the pre- and postemergence 

control of annual broadleaf weeds and nutsedges in selected crops, residential turfgrass, and 

ornamentals. Halosulfuron-methyl is sold in the US as dry flowable/water-dispersible granule 

formulations or as emulsifiable concentrates.

The most recent risk assessment for halosulfuron-methyl was conducted in 2010 (DP# D366410, 

W. Phang, 4/5/10). Refer to Attachment 1 (Tables 1 and 2) for chemical identity of parent and 

structures of parent and metabolites. 

Hazard Identification/Toxicology

The toxicology database is adequate to support the existing tolerances, with the exception of the 

requirement for an immunotoxicity study. The immunotoxicity study is required under 40 CFR 

§158.500, and has been called in as a condition of registration (D366410, W. Phang, 4/5/10). 

The 28-day inhalation toxicity study has been waived (HASPOC Meeting, TXR # 0054045, DP#

D397243, D. Smegal, MPH, 2/22/12). A point of departure (POD) derived from the oral toxicity 

study data is sufficiently protective for risk assessment of potential maximum exposure via 

inhalation. The weight of evidence approach that was used by HASPOC considered all of the 

available hazard and exposure information for halosulfuron-methyl, including: (1) the use of an 

oral point of departure (POD) that results in margins of exposure (MOEs) greater than 12,000 

(the lowest MOE) for risk via the inhalation route resulting from occupational and residential 

exposures; (2) the physical/chemical properties and low volatility of halosulfuron-methyl; (3) the 

toxicological profile of halosulfuron-methyl is limited to general systemic toxicity with no target 

organ toxicity; and (4) the low acute inhalation toxicity of halosulfuron-methyl.

Halosulfuron-methyl has low acute toxicity via the oral, dermal, and inhalation routes. It is a 

non-irritant for skin and eyes and is not a dermal sensitizer. With repeated dosing, halosulfuron 

produces non-specific effects, which are frequently characterized by reduced body weight and 

body weight gains in the test animals. Carcinogenicity studies in rats and mice show no increase 

in treatment-related tumor incidence, and it is classified as “not likely to be carcinogenic to 

humans.” The results of both acute and subchronic neurotoxicity studies show no neurotoxic 

effects. Halosulfuron-methyl is negative for mutagenicity in a battery of genotoxicity studies. 

Although the data indicated an increase in qualitative susceptibility in fetuses following prenatal 

exposure in rats and rabbits, the developmental effects were seen in the presence of maternal 
Page 4 of 30

effects and clear NOAELs (no observed adverse effect levels) and LOAELs (lowest observed 

adverse effect levels) were established for both maternal and developmental effects. In addition, 

the developmental effects in rats were seen at doses approaching the limit dose (1000 

mg/kg/day). It was concluded that the degree of concern was low and there was no residual 

uncertainty in either the rat or rabbit developmental toxicity study. The Food Quality Protection 

Act (FQPA) safety factor was reduced to 1X. 

The points of departure (PODs) and toxicity endpoints from the most recent risk assessment 

(DP# D366410, W. Phang, 4/5/10) are summarized in Attachment 3, Table 4 (Dietary and NonOccupational) and Table 5 (Occupational). The toxicity endpoints and PODs for risk 

assessment were selected for the following exposure scenarios: acute and chronic dietary, shortand intermediate-term incidental oral, dermal and inhalation. Because of a common effect (i.e.,

body weight gain changes) seen in the studies selected for the endpoints for all three routes of 

exposure, MOEs and exposures can be aggregated where appropriate.

Conclusions: The toxicology database is adequate, with the exception of the requirement for an 

immunotoxicity study, which has been required as a condition of registration. Depending on the 

results of the additional study, endpoints may need to be reevaluated and a new risk assessment 

may be needed. 

Dietary Exposure

The most recent dietary exposure assessment (DP# D367059, D. Rate, 3/4/10) was conducted 

using the Dietary Exposure Evaluation Model DEEM-FCIDTM, Version 2.03, which uses food 

consumption data from the US Department of Agriculture’s (USDA’s) Continuing Surveys of 

Food Intakes by Individuals (CSFII) from 1994-1996 and 1998. In the most recent risk 

assessment, unrefined acute and chronic dietary (food and drinking water) exposure assessments

were conducted for all food uses and drinking water. The residue levels used in the assessments

for all commodities were tolerance levels and the assessments were conducted using the 

assumption that 100% of the registered/proposed crops were treated (100% CT). Default 

(DEEM 7.81) processing factors were used unless processing studies were available. 

Estimated concentrations of halosulfuron-methyl in drinking water from use on rice, which 

reflected the highest use rate, were provided by the Environmental Fate and Effects Division 

(EFED) and incorporated directly into the acute and chronic assessments. A Tier 1 drinking 

water assessment for the use on rice was performed using the FQPA Index Reservoir Screening 

Tool (FIRST) modeling. Estimated drinking water concentrations (EDWCs) for halosulfuronmethyl are based on estimated surface water residues reflecting a maximum annual application 

rate of 0.125 lb ai/A to rice. The acute estimated drinking water concentration (acute EDWC) of 

halosulfuron-methyl is not expected to exceed 59.2 ppb (0.0592 ppm). The annual mean 

(chronic) estimated drinking water concentration (chronic EDWC) of halosulfuron-methyl is not 

expected to exceed 59.2 ppb (0.0592 ppm).

The acute and chronic dietary (food and drinking water) exposures to halosulfuron-methyl are

below HED’s level of concern for the general US population and all population subgroups. For 

the general US population, an appropriate dose/endpoint attributable to a single dose was not 
Page 5 of 30

observed in the reviewed oral toxicity studies. However, a toxicological endpoint attributable to 

a single dose of halosulfuron-methyl was observed for the subgroup of females 13-49 years old. 

The acute dietary exposure estimate at the 95th percentile is <1% of the acute population adjusted 

dose (aPAD) for females 13-49 years old. The chronic dietary exposure estimates are 2% of the 

chronic PAD (cPAD) for the general US population and 5% of the cPAD for all infants (<1 year 

old), the most highly exposed population subgroup.

HED classified halosulfuron-methyl as “not likely to be a human carcinogen;” therefore, 

quantification of human cancer risk was not conducted. 

The residue chemistry database is sufficient to support current registrations. The nature of the 

residue in plants and livestock has been defined, and adequate enforcement methods are 

available. Adequate storage stability, field trial, and rotational crop data are available. Based on 

the absence of the parent compound in the confined studies and in the limited field rotational 

crop studies, with the exception of one forage sample, rotational crop tolerances and restrictions 

are not required for halosulfuron-methyl.

Since the most recent risk assessment, an amended registration (label amendment) to add postemergent use on rice was submitted by Canyon Group LLC (agent Gowan Company) and has 

been reviewed (DP# D391400, S. Funk, 9/20/11). Sixteen rice field trials and a rice processing 

study were submitted. The combination pre-emergence and foliar postemergence use is already 

registered to another company (Helm Agro USA, Inc, EPA Registration No. 74530-321). Thus, 

the use pattern has been considered as part of previous human health risk assessments. No new 

tolerances are required in connection with the petition. The existing tolerance for rice grain is 

adequate. However, HED is recommending that the established tolerance for halosulfuronmethyl in rice straw be revoked since rice straw is no longer considered a significant feed item in 

the US. The recent action on rice does not increase the dietary burdens for ruminants or poultry. 

The established livestock tolerances are adequate. 

Conclusions: A new risk assessment is not expected to be needed in the registration review 

process. New risk assessments including new dietary exposure assessments will be conducted in 

connection with a pending PRIA action for new uses on proso millet and Crop Group 17 (Grass 

Forage, Fodder, and Hay Group). In connection with the PRIA actions, the dietary exposure 

assessment will be updated to the new version of DEEM (Version 3.04), which may change 

dietary exposure estimates slightly as compared to Version 2.03. The tolerance expression will 

be reviewed during registration review. The chemical nomenclature for halosulfuron-methyl in 

the tolerance expression should be consistent with either the Chemical Abstracts Service (CAS) 

nomenclature (methyl 3-chloro-5-[[[[(4,6-dimethoxy-2-

pyrimidinyl)amino]carbonyl]amino]sulfonyl]-1-methyl-1H-pyrazole-4-carboxylate) or the 

IUPAC nomenclature (methyl 3-chloro-5-(4,6-dimethoxypyrimidin-2-ylcarbamoylsulfamoyl)-1-

methylpyrazole-4-carboxylate). 
Page 6 of 30

Residential Exposure

Residential use patterns include residential turfgrass, ornamentals, and recreational turf areas. 

There is potential for short- and intermediate-term residential exposure to halosulfuron-methyl 

during handling (mixing, loading, and applying) and post-application activities.

For residential exposure, the durations of exposure are expected to be short-term (1-30 days) and 

intermediate-term (1-6 months); long-term exposures are not anticipated. The level of concern 

(LOC) for risk estimates is a margin of exposure (MOE) of less than 100 for short- and 

intermediate-term exposure.

Residential Handlers

Residential handlers are likely to be exposed to halosulfuron-methyl residues via dermal and 

inhalation routes during handling activities. Specific potential residential handler scenarios were 

previously assessed for turfgrass at a maximum single application rate of 0.062 lb ai/A, and the 

calculated combined (dermal + inhalation) risk estimate for residential handlers was an MOE of 

20,000 (DP# D278588, K. O’Rourke, 8/28/2002). However, HED policies have since changed 

and new unit exposure values have been established. The most recent residential handler 

assessment was based on the HED Exposure Science Advisory Council (ExpoSAC) Residential

Standard Operating Procedures (SOPs) and the Pesticide Handler Exposure Database (PHED),

Version 1.1 unit exposures, as presented in the PHED Surrogate Exposure Guide (August 1998). 

Although there was no identified risk estimate of concern, an assessment for the higher 

registered application rate of 0.14 lb ai/A (based on label EPA Reg. No. 81880-24) has never 

been conducted. Also, the toxicological endpoints for short-term dermal and short- and 

intermediate-term inhalation exposures were changed.

Table 6 (Attachment 4) summarizes residential handler use patterns and corresponding MOEs. 

Residential Post-Application

Adults are likely to be exposed to halosulfuron-methyl residues via the dermal route during postapplication activities. Young children are likely to be exposed to halosulfuron-methyl via the 

dermal and oral routes during post-application activities. Exposure risk estimates from lawn 

treatment were assessed for (1) adults and children’s post-application dermal exposure, (2)

children’s incidental ingestion of pesticide residues on lawns from hand-to-mouth transfer, (3) 

children’s object-to-mouth transfer from mouthing of pesticide-treated turfgrass, and (4) 

children’s incidental ingestion of soil from pesticide-treated residential areas.

There were no identified risk estimates of concern for young children with dermal and incidental 

oral MOEs ranging from 1,100 to 3,200,000 and for adults with dermal MOEs ranging from 

1,800 to 7,000. However, HED policies have since changed and new unit exposure values have 

been established. Furthermore, a higher registered application rate of 0.14 lb ai/A has never been 

assessed. Also, the toxicological endpoint for short-term dermal exposure was changed.
Page 7 of 30

Table 7 (Attachment 4) summarizes residential post-application use patterns and corresponding 

MOEs.

Conclusions: There is sufficient information available to assess residential exposure. Although 

all residential exposure scenarios have not been assessed using current ORE policy and current 

toxicological endpoints, a new residential assessment is not expected to be needed in the 

registration review process. An updated residential exposure assessment will be conducted in 

connection with the pending PRIA action.

 

Aggregate Risk Assessment

In the most recent human health risk assessment (DP# D366410, W. Phang, 4/5/10), acute, shortterm, and intermediate-term aggregate exposures were assessed. Aggregate assessments 

considered exposures from food, drinking water, and residential uses. All risk estimates were 

below the level of concern. 

The chronic or long-term aggregate risk assessment takes into account average exposure 

estimates from dietary consumption of halosulfuron-methyl (food and drinking water) and 

residential uses. Based on the halosulfuron-methyl use pattern, no long-term residential 

exposures are expected. Therefore, the chronic aggregate assessment includes only food and 

water and is equivalent to the chronic dietary assessment, for which the risk estimate is below 

HED’s level of concern. 

A cancer aggregate risk assessment was not performed because halosulfuron-methyl has not been 

shown to be carcinogenic.

Conclusions: Since HED anticipates conducting a new risk assessment in 2012 in conjunction 

with proposed new halosulfuron uses/tolerances under PRIA, the 2012 assessment may preclude 

the need to conduct additional aggregate assessments for registration review.

HED expects to address the following issues in the new risk assessment in 2012: A new 

aggregate assessment may be needed depending on the results of the immunotoxicity study and 

the reevaluation of databases using current policies. Additional toxicology studies are required

so endpoints may need to be reevaluated. A new version of DEEM (Version 3.04) will be used 

in dietary exposure assessments in the future, which may change dietary exposure estimates. 

Residential exposure assessments must be reassessed using current Occupational and Residential 

Exposure (ORE) policy, the revised toxicological inhalation endpoint established in 2002, and 

including the highest application rates. In addition, the Agency may need to consider changes 

that consider off-target movement of pesticides into residential settings.

Occupational Exposure

Halosulfuron-methyl is registered for several agricultural uses and for use in non-crop areas. 

There is potential for short- and intermediate-term occupational exposure to halosulfuron-methyl 

during handling (mixing, loading, and applying) and post-application activities. Long-term 
Page 8 of 30

exposures are not anticipated. The level of concern (LOC) for risk estimates is a margin of 

exposure (MOE) of less than 100 for short- and intermediate-term exposure.

Occupational Handlers

Previous occupational handler exposure and risk assessments were conducted for all of the 

agricultural crop use sites based on PHED. However, HED policies have since changed yielding 

updated acreage assumptions as well as updated unit exposure values. In addition, all 

assessments conducted prior to updated FQPA policies did not include any inhalation exposure 

risk estimates. Also, the toxicological endpoints for short-term dermal and short- and 

intermediate-term inhalation exposures were changed.

Exposure and risk assessments have not been conducted for any of the registered non-crop areas. 

The highest registered application rate to be assessed for non-crop area occupational handler 

exposure is 0.14 lb ai/A (based on label EPA Reg. No. 81880-24). 

Table 8 (Attachment 5) lists the occupational handler scenarios for each use site and the 

corresponding MOEs, if previously assessed.

Occupational Post-Application

Occupational post-application exposure can occur via the dermal and/or inhalation routes. 

Several post-application dermal exposures and risk estimates have been previously assessed, 

resulting in risk estimates which are not of concern (MOEs ranging from 560 to 83,000). HED 

policies have since changed, i.e., new unit exposure values and transfer coefficients (TCs) have 

been established. However, an up-to-date occupational assessment is not expected to be needed 

during registration review as these changes are not expected to affect the risk conclusions of the 

previous assessment. 

Table 9 (Attachment 5) summarizes the previously assessed occupational post-application 

scenarios along with the corresponding MOEs. Based on the current assessments, the interim 

restricted entry interval (REI) of 12 hours is acceptable for all crops.

Based on the Agency's current practices, a quantitative occupational post-application inhalation 

exposure assessment has not been performed for halosulfuron-methyl at this time. However, 

there are multiple potential sources of post-application inhalation exposure to individuals 

performing post-application activities in previously treated fields. These potential sources 

include volatilization of pesticides and resuspension of dusts and/or particulates that contain 

pesticides. The Agency sought expert advice and input on issues related to volatilization of 

pesticides from its Federal Insecticide, Fungicide, and Rodenticide Act Scientific Advisory Panel 

(SAP) in December 2009. The Agency received the SAP’s final report on March 2, 2010 

(http://www.epa.gov/scipoly/SAP/meetings/2009/120109meeting.html). The Agency is in the 

process of evaluating the SAP report as well as available post-application inhalation exposure 

data generated by the Agricultural Reentry Task Force and may, as appropriate, develop policies 

and procedures to identify the need for and, subsequently, the way to incorporate occupational 

post-application inhalation exposure into the Agency's risk assessments. If new policies or 
Page 9 of 30

procedures are put into place, the Agency may revisit the need for a quantitative occupational 

post-application inhalation exposure assessment for halosulfuron-methyl.

Conclusions: There is sufficient information available to assess occupational exposure. 

However, not all occupational exposure scenarios have been assessed using current ORE policies

and current toxicological endpoints. HED does not anticipate conducting an up-to-date 

occupational assessment as it does not expect changes in unit exposures and transfer coefficients

to affect the risk conclusions of the previous assessment. If toxicological endpoints change 

based on the pending immunotoxicity study, then HED may revisit the need for an updated 

occupational assessment.

Endocrine Disruptor Screening Program (EDSP)

As required by the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) and the Federal 

Food, Drug, and Cosmetic Act (FFDCA), EPA reviews numerous studies to assess potential 

adverse outcomes from exposure to chemicals. Collectively, these studies include acute, 

subchronic and chronic toxicity, including assessments of carcinogenicity, neurotoxicity, 

developmental, reproductive, and general or systemic toxicity. These studies include endpoints 

which may be susceptible to endocrine influence, including effects on endocrine target organ 

histopathology, organ weights, estrus cyclicity, sexual maturation, fertility, pregnancy rates, 

reproductive loss, and sex ratios in offspring. For ecological hazard assessments, EPA evaluates 

acute tests and chronic studies that assess growth, developmental and reproductive effects in 

different taxonomic groups. As part of its most recent registration decision, EPA reviewed these 

data and selected the most sensitive endpoints for relevant risk assessment scenarios from the 

existing hazard database. However, as required by FFDCA section 408(p), halosulfuron-methyl 

is subject to the endocrine screening part of the Endocrine Disruptor Screening Program (EDSP). 

EPA has developed the EDSP to determine whether certain substances (including pesticide 

active and other ingredients) may have an effect in humans or wildlife similar to an effect 

produced by a “naturally occurring estrogen, or other such endocrine effects as the Administrator 

may designate.” The EDSP employs a two-tiered approach to making the statutorily required 

determinations. Tier 1 consists of a battery of 11 screening assays to identify the potential of a 

chemical substance to interact with the estrogen, androgen, or thyroid (E, A, or T) hormonal 

systems. Chemicals that go through Tier 1 screening and are found to have the potential to 

interact with E, A, or T hormonal systems will proceed to the next stage of the EDSP where EPA 

will determine which, if any, of the Tier 2 tests are necessary based on the available data. Tier 2 

testing is designed to identify any adverse endocrine-related effects caused by the substance, and 

establish a dose-response relationship between the dose and the E, A, or T effect. 

Under FFDCA section 408(p), the Agency must screen all pesticide chemicals. Between 

October 2009 and February 2010, EPA issued test orders/data call-ins for the first group of 67 

chemicals, which contains 58 pesticide active ingredients and 9 inert ingredients. Halosulfuronmethyl is not among the group of 58 pesticide active ingredients on the initial list to be screened 

under the EDSP. Accordingly, as part of registration review, EPA will issue future EDSP 

orders/data call-ins, requiring the submission of EDSP screening assays for halosulfuron-methyl.

For further information on the status of the EDSP, the policies and procedures, the list of 67 
Page 10 of 30

chemicals, future lists, the test guidelines and the Tier 1 screening battery, please visit our 

website: http://www.epa.gov/endo/.

Public Health and Pesticide Epidemiology Data

The evaluation of the OPP Incident Data System (IDS) indicated that no incidents were 

identified in the United States from January 1, 2006 through November 2, 2011 for the single 

chemical halosulfuron-methyl (DP# D395323, S. Recore, 12/8/11). In Aggregate IDS from 

January 1, 2006 to November 2, 2011, there are 14 incidents reported for halosulfuron-methyl. 

Because it falls within the categories reported as counts (which includes minor, unknown or no 

effects), there is no unique report that provides details about the incident and single chemical 

incidents are not distinguished from multiple chemical incidents; however, a high frequency of 

incidents indicates there is a high potential for exposure and vice versa. For halosulfuronmethyl, there appears to be a low potential for exposure. Halosulfuron-methyl is not included in 

the Agricultural Health Study (AHS), and therefore, the AHS does not provide information for 

this report. Based on the low frequency and severity of incident cases for halosulfuron-methyl, 

there does not appear to be a concern at this time that would warrant further investigation. The 

Agency will continue to monitor the incident information. If a concern is triggered, additional 

analysis will be included in the risk assessment.

Tolerance Assessment and International Harmonization

Permanent US tolerances are established under 40 CFR §180.479(a)(1) for residues of the 

herbicide halosulfuron-methyl, methyl 5-[(4,6-dimethoxy-2-

pyrimidinyl)amino]carbonylaminosulfonyl]-3-chloro-1-methyl-1H-pyrazole-4-carboxylate, 

including its metabolites and degradates, in/on the meat byproducts of cattle, goat, hog, horse, 

and sheep at 0.1 ppm. Compliance with the tolerance levels specified is to be determined by 

measuring only those halosulfuron-methyl residues containing the 3-chlorosulfonamide (3-CSA) 

moiety, expressed as the stoichiometric equivalent of halosulfuron-methyl.

Permanent US tolerances are established under 40 CFR §180.479(a)(2) for residues of the 

herbicide halosulfuron-methyl, methyl 5-[(4,6-dimethoxy-2-

pyrimidinyl)amino]carbonylaminosulfonyl]-3-chloro-1-methyl-1H-pyrazole-4-carboxylate, 

including its metabolites and degradates, in/on a variety of field, fruit, and vegetable crop 

commodities at levels ranging from 0.05 to 2.0 ppm. Compliance with the tolerance levels 

specified is to be determined by measuring only halosulfuron-methyl.

There are no Codex, Canadian, or Mexican maximum residue limits (MRLs) established for 

residues of halosulfuron-methyl in crop or livestock commodities (see Attachment 2, Table 3).

The US tolerance expression will be reviewed during registration review since the chemical 

nomenclature for halosulfuron-methyl in the tolerance expression should be consistent with 

either the CAS or IUPAC nomenclature. 
Page 11 of 30

Environmental Justice

Potential areas of environmental justice concerns, to the extent possible, will be considered in the 

registration review, in accordance with US Executive Order 12898, "Federal Actions to Address 

Environmental Justice in Minority Populations and Low-Income Populations," 

http://www.eh.doe.gov/oepa/guidance/justice/eo12898.pdf).

As a part of every pesticide risk assessment, OPP considers a large variety of consumer 

subgroups according to well-established procedures. In line with OPP policy, HED estimates 

risks to population subgroups from pesticide exposures that are based on patterns of that 

subgroup’s food and water consumption, and activities in and around the home that involve 

pesticide use in a residential setting. Extensive data on food consumption patterns are compiled 

by the USDA under the Continuing Survey of Food Intake by Individuals (CSFII) and are used 

in pesticide risk assessments for all registered food uses of a pesticide. These data are analyzed 

and categorized by subgroups based on age, season of the year, ethnic group, and region of the 

country. Additionally, OPP is able to assess dietary exposure to smaller, specialized subgroups 

and exposure assessments are performed when conditions or circumstances warrant. Whenever 

appropriate, non-dietary exposures based on home use of pesticide products and associated risks 

for adult applicators and for toddlers, youths, and adults entering or playing on treated areas 

postapplication are evaluated. Further considerations are currently in development as OPP has 

committed resources and expertise to the development of specialized software and models that 

consider exposure to bystanders and farm workers as well as lifestyle and traditional dietary 

patterns among specific subgroups.

Cumulative 

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 as 

to halosulfuron-methyl and any other substances and halosulfuron-methyl does not appear to 

produce a toxic metabolite produced by 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/.

Human Studies

Past halosulfuron-methyl risk assessments rely in part on data from studies in which adult human 

subjects were intentionally exposed to a pesticide to determine their dermal and inhalation 

exposure. Many such studies, involving exposure to many different pesticides, comprise generic 

pesticide exposure databases such as the Pesticide Handlers Exposure Database (PHED), the 

Outdoor Residential Exposure Task Force (ORETF), and the Agricultural Reentry Task Force 

(ARTF) Database. EPA has reviewed all the studies supporting these multi-pesticide generic 

exposure databases, and has found no clear and convincing evidence that the conduct of any of 

them was either fundamentally unethical or significantly deficient relative to the ethical 
Page 12 of 30

standards prevailing at the time the research was conducted. All applicable requirements of 

EPA’s Rule for the Protection of Human Subjects of Research (40 CFR Part 26) have been 

satisfied, and there is no regulatory barrier to continued reliance on these studies.

Data Requirements

As shown in References below, seven human health risk assessments have been conducted for 

halosulfuron-methyl between 1999 and 2010. A recent Section 3 petition for a label amendment 

on rice has been reviewed. As shown in detail in Attachment 6, there are outstanding data gaps 

associated with the Section 3 assessments, including a requirement for an immunotoxicity study

and the requirement that an analytical reference standard for the rearrangement ester (RRE) of 

halosulfuron-methyl be submitted to the EPA National Pesticide Standards Repository. 

References

Memoranda Relevant to Registration Review of Halosulfuron-methyl

Author Barcode 

(DP#)

Date Title

Risk Assessments

S. Weiss D251257 2/9/99 PP#6F4661 & PP#8F4937. Human Health Risk Assessment for 

Halosulfuron-methyl: New Uses on Sweet Corn, Popcorn, Cotton, 

Tree-nuts, and Rice; and Revised Tolerances on Field Corn, Grain 

Sorghum, and Sugar Cane

M. Rust D261708 6/29/00 HED Risk Assessment: Human Health Risk Assessment for 

Halosulfuron-methyl to be used on Subgroup 9B Crops 

(Squash/Cucumber Subgroup)

M. Rust D271574 10/16/01 HED Risk Assessment: Human Health Risk Assessment for 

Halosulfuron-methyl to Support Request for New Use in/on Melons 

(Crop Subgroup 9A)

M. Rust D278447 9/4/02 HED Risk Assessment: Human Health Risk Assessment for 

Halosulfuron-methyl to Support Request for New Use in/on Fruiting 

Vegetables (Crop Group 8), Dry Beans and Snap Beans

M. ClockRustD331643 9/21/06 Halosulfuron-methyl: Human Health Risk Assessment for Proposed 

Uses on Alfalfa

W. Phang D358031 6/30/09 Halosulfuron-methyl: Human Health Risk Assessment for Proposed 

Uses on Soybean

W. Phang D366410 4/5/10 Halosulfuron-Methyl: Human Health Risk Assessment for IR-4 

Proposed Uses on Crop Group 6B Succulent Shelled Pea and Bean 

Subgroup, Crop Group 1C Tuberous and Corn Vegetables Subgroup, 

Crop Group 6C Dried Shelled Pea and Bean (Except Soybean), 

Subgroup 13-07B Bushberry, Okra, Apples, and Rhubarb

Residue Chemistry

G. J. Herndon D173627 7/30/92 PP#2G4073. Temporary Tolerance Petition and Experimental Use 

Permit for Use of MON 12000 (Permit®) on Corn; 000524-EUP-TO. 

Evaluation of Analytical Method and Residue Data.

G. J. Herndon D189189 3/7/94 Permanent Tolerance Request for Use of MON 12000 (Halosulfuron) 

on Field Corn and Grain Sorghum (Milo). Evaluation of Analytical 

Method and Residue Data.

A. Acierto D271686 5/16/01 PP# 0E6206. Halosulfuron-methyl On Melon Subgroup. Review of 

Analytical Methods and Magnitude of Residue Data.

N. Dodd D358029 4/23/09 Halosulfuron-methyl. Application for Amended Section 3 
Page 13 of 30

Memoranda Relevant to Registration Review of Halosulfuron-methyl

Author Barcode 

(DP#)

Date Title

Registration to Add Uses on Soybeans. Summary of Analytical 

Chemistry and Residue Data.

D. Rate D367058 3/3/10 Halosulfuron-methyl. Application for Section 3 Registration of 

Sandea® Herbicide (EPA Reg. No. 81880-18) and GWN-3061 

Herbicide (EPA Reg. No. 81880-2) to Add New Uses on: Pea and 

Bean, Succulent Shelled, Subgroup 6B; Vegetable, Tuberous and 

Corm, Subgroup 1C; Rhubarb; Bushberry Subgroup 13-07B; Pea and 

Bean, Dried Shelled, Except Soybean, Subgroup 6C; Apple; and 

Okra. Summary of Analytical Chemistry and Residue Data.

S. Funk D391400 9/20/11 H Halosulfuron-methyl. Application for Section 3 Registration of 

Permit PlusTM Herbicide (EPA Reg. No. 81880-26) to Add a New 

Use on Rice. Summary of Analytical Chemistry and Residue Data.

Dietary Exposure Assessment

D. Rate D367059 3/4/10 H Halosulfuron-methyl Acute and Chronic Aggregate Dietary (Food 

and Drinking Water) Exposure and Risk Assessments for the Section 

3 Registration Action on Pea and Bean, Succulent Shelled, Subgroup 

6B; Vegetable, Tuberous and Corm, Subgroup 1C; Rhubarb; 

Bushberry Subgroup 13-07B; Apple; and Okra.

Occupational Residential Exposure

G. J. Herndon D223266 7/22/98 Halosulfuron. Label Amendment to Increase Application Rates on 

Grain Sorghum (Milo)

M. Rust D265726 6/21/00 Occupational and Residential Risk Assessment to Support Request for 

New Uses of Halosulfuron-methyl on Vegetables in the Cucumber 

and Squash Subgroup (Subgroup 9B)

J. Arthur D273929 4/20/01 Occupational and Residential Risk Assessment to Support Request for 

New Uses of Halosulfuron-methyl on Vegetables in the Cucumber 

and Squash Subgroup (Subgroup 9B)

J. Arthur D271574 9/17/01 Halosulfuron-methyl: Occupational and Residential Risk Assessment 

to Support Request for Use on Melons.

K. O’Rourke D278588 8/28/02 Halosulfuron-methyl: Occupational and Residential Risk Assessment 

to Support Request for Use on Dry Beans, Snap Beans, Asparagus, 

and Fruiting Vegetables.

K. O’Rourke D331645 8/29/06 Halosulfuron-methyl: Occupational and Residential Risk Assessment 

to Support Request for Use on Alfalfa.

B. O’Keefe D359456 4/27/09 Halosulfuron-methyl: Occupational and Residential Exposure 

Assessment for proposed field use of halosulfuron-methyl on 

soybeans. 

N. Tsaur D367060 3/4/10 Halosulfuron-methyl. Occupational and Residential Exposure 

Assessment for Proposed Field Use of Halosulfuron-Methyl on 

Succulent Shelled Peas and Beans (Subgroup 6B), Tuberous and 

Corm Vegetables (Subgroup 1C), Rhubarb, Bushberry (Subgroup 13-

07B), Dried Shelled Peas and Beans (Except Soybean, Subgroup 6C), 

Apples, and Okra.

N. Tsaur D393885 10/13/11 Halosulfuron-methyl. Occupational and Residential Exposure 

Assessment for a Proposed Addition of Post-Emergent Weed Control 

Use on Rice.

Toxicology

S. Recore D395323 12/8/11 Halosulfuron-methyl: Review of Human Incidents

D. Smegal D397243 2/22/12 Halosulfuron-methyl: Summary of Hazard and Science Policy 

Council (HASPOC) Meeting of February 9, 2012: Recommendations 

on waiver requests for 28-day inhalation study.
Page 14 of 30

Attachments

1. Chemical Identity Tables

2. Tolerance Summary Table

3. Endpoint Selection Table

4. Residential Exposure Tables

5. Occupational Exposure Tables

6. Outstanding Deficiencies to be Addressed by the Registrants
Page 15 of 30

Attachment 1

Chemical Identity Tables

Table 1. Chemical Identity – Halosulfuron-methyl

Common Name halosulfuron-methyl

Chemical Name (CAS) methyl 3-chloro-5-[[[[(4,6-dimethoxy-2-

pyrimidinyl)amino]carbonyl]amino]sulfonyl]-1-methyl-1H-pyrazole-4-

carboxylate

PC Code 128721

Chemical Abstracts No. 100784-20-1

Registration Review Case No. NA

Chemical Class sulfonylurea 

Chemical Structure 

Table 2. Structures of Metabolites

Chemical structure of

3-chlorosulfonamide moiety 

(3-CSA)

3-chloro-1-methyl-5-sulfamoyl1H-pyrazole-4-carboxylic acid

Rearrangement ester (RRE) of 

halosulfuron-methyl

N

N

CH3

Cl

N

N N

H

N

H

O

S

O

O

O

CH3

O

CH3

O

O

CH3

N

N

CH3

Cl

NH2 S

O

O

OH

O

N

N

O

CH3

O

CH3

N

H N

N

CH3

Cl

O

O

CH3
Page 16 of 30

Attachment 2

Tolerance/MRL Table

As shown in the table below, there are no Codex, Canadian, or Mexican maximum residue limits 

(MRLs) established for residues of halosulfuron-methyl in crop or livestock commodities.

Halosulfuron-methyl (128721; 10/03/2011)

Table 3. Summary of US and International Tolerances and Maximum Residue Limits 

Residue Definition:

US Canada Mexico Codex 1 2

40 CFR §180.479 (a) (1): Tolerances are established for residues 

of the herbicide halosulfuron-methyl, methyl 5-[(4,6-dimethoxy2-pyrimidiny)amino] carbonylaminosulfonyl]-3-chloro-1-methyl1H-pyrazole-4-carboxylate, including its metabolites and 

degradates, in or on the commodities in the following table. 

Compliance with the tolerance levels specified in the following 

table is to be determined by measuring only those halosulfuronmethyl residues containing the 3-chlorosulfonamide (3-CSA) 

moiety, expressed as the stoichiometric equivalent of 

halosulfuron-methyl.

None None

Commodity Tolerance (ppm) /Maximum Residue Limit (mg/kg) 1

US Canada Mexico Codex 1 2

Cattle, meat byproducts 0.1

Goat, meat byproducts 0.1

Hog, meat byproducts 0.1

Horse, meat byproducts 0.1

Sheep, meat byproducts 0.1

US Canada Mexico Codex 1 2

40 CFR §180.479(a)(2): Tolerances are established for residues 

of the herbicide halosulfuron-methyl, methyl 5-[(4,6-dimethoxy2-pyrimidiny)amino]carbonylaminosulfonyl]-3-chloro-1-methyl1H-pyrazole-4-carboxylate, including its metabolites and 

degradates, in or on the commodities in the following table. 

Compliance with the tolerance levels specified in the following 

table is to be determined by measuring only halosulfuron-methyl.

None None

Commodity Tolerance (ppm) /Maximum Residue Limit (mg/kg)

US Canada Mexico Codex 1 2

Alfalfa, forage 1.0

Alfalfa, hay 2.0

Almond, hulls 0.2

Apple 0.05

Asparagus 0.8

Bean, dry, seed 0.05

Bushberry, subgroup 13-07B 0.05

Corn, field, forage 0.2

Corn, field, grain 0.05

Corn, field, stover 0.8

Corn, pop, grain 0.05

Corn, pop, stover 0.8

Corn, sweet, forage 0.2
Page 17 of 30

Table 3. Summary of US and International Tolerances and Maximum Residue Limits 

Residue Definition:

US Canada Mexico Codex 1 2

Corn, sweet, kernel plus cob with 

husks removed

0.05

Corn, sweet, stover 0.8

Cotton, gin byproducts 0.05

Cotton, undelinted seed 0.05

Melon subgroup 9A 0.1

Nut, tree, group 14 0.05

Okra 0.05

Pea and bean, succulent shelled, 

subgroup 6

0.05

Pea and bean, succulent shelled, 

subgroup 6B

0.05

Pistachio 0.05

Rhubarb 0.05

Rice, grain 0.05

Rice, straw 0.2

Sorghum, grain, forage 0.05

Sorghum, grain, grain 0.05

Sorghum, grain, stover 0.1

Soybean, seed 0.05

Squash/Cucumber subgroup 9B 0.5

Sugarcane, cane 0.05

Vegetable, fruiting, group 8 0.05

Vegetable, tuberous and corm, 

subgroup 1C

0.05

Completed by: M. Negussie; 10/05/2011

1 Mexico adopts US tolerances and/or Codex MRLs for its export purposes.

2 * = absent at the limit of quantitation; Po = postharvest treatment, such as treatment of stored grains. PoP = 

processed postharvest treated commodity, such as processing of treated stored wheat. (fat) = to be measured on the 

fat portion of the sample. MRLs indicated as proposed have not been finalized by the CCPR and the CAC.
Page 18 of 30

Attachment 3

Summary of Toxicity Endpoints and Points of Departure of Halosulfuron-methyl

Table 4. Toxicological Doses and Endpoints for Halosulfuron-Methyl for Dietary and Non-Occupational 

Human Health Risk Assessments.

Exposure/

Scenario

Point of 

Departure

Uncertainty/

FQPA Safety 

Factors

RfD, PAD, 

Level of 

Concern for 

Risk 

Assessment

Study and Toxicological Effects

Acute Dietary

(Females 13-49 

years of age)

NOAEL= 

50 

mg/kg/day

UFA= 10x

UFH= 10x

FQPA SF= 1x

Acute RfD = 0.5 

mg/kg/day

aPAD =0.5 

mg/kg/day

Developmental Toxicity - Rabbit

LOAEL = 150 mg/kg/day based on decreased 

mean litter size, increased number of 

resorptions (total and per dam) and increased 

postimplantation loss (developmental 

toxicity).

Acute Dietary 

(General 

Population 

including Infants 

and Children)

N/A N/A N/A No adverse effect attributable to a single dose 

was identified; therefore, no dose/endpoint 

was selected for this exposure scenario.

Chronic 

Dietary (All 

Populations)

NOAEL= 

10 

mg/kg/day

UFA= 10x

UFH= 10x

FQPA SF= 1x 

Chronic RfD = 

0.1

mg/kg/day

cPAD = 0.1 

mg/kg/day

Chronic Toxicity - Dog

LOAEL = 40 mg/kg/day based on decreased 

body weight gains in females.

Incidental Oral

Short-Term (1-

30 days)

NOAEL= 

50 

mg/kg/day

UFA= 10x

UFH= 10x

FQPA SF= 1x 

Residential LOC 

for MOE = 100

Developmental Toxicity - Rabbit

LOAEL = 150 mg/kg/day based on decreased 

body weight gain, food consumption, and 

food efficiency (maternal toxicity). 

Incidental Oral 

IntermediateTerm (1-6 

months)

NOAEL= 

10 

mg/kg/day

UFA= 10x

UFH= 10x

FQPA SF= 1x 

Residential LOC 

for MOE = 100

13 Week Subchronic Toxicity - Dog

LOAEL = 40 mg/kg/day based on decreased 

body weight gains and food efficiency along 

with hematological and clinical chemistry 

changes.

Dermal ShortTerm (1-30 

days)

NOAEL= 

100 

mg/kg/day

UFA= 10x

UFH= 10x

FQPA SF= 1x 

Residential LOC 

for MOE = 100

21-Day Dermal Toxicity Study - Rat

LOAEL = 1000 mg/kg/day based on 

decreased body weight gain in males.

Dermal 

IntermediateTerm (1-6 

months)

NOAEL=10 

mg/kg/day

+

UFA= 10x

UFH= 10x

FQPA SF= 1x 

Residential LOC 

for MOE = 100

13 Week Subchronic Toxicity - Dog

LOAEL = 40 mg/kg/day based on decreased 

body weight gains and food efficiency along 

with hematological and clinical chemistry 

changes.

Inhalation 

Short- Term 

(1-30 days)

NOAEL = 

50 

mg/kg/day

UFA= 10x

UFH= 10x

FQPA SF= 1x 

Residential LOC 

for MOE = 100

Developmental Toxicity - Rabbit

LOAEL = 150 mg/kg/day based on decreased 

body weight gain, food consumption, and 

food efficiency (maternal toxicity).

Inhalation 

IntermediateTerm (1-6 

months)

NOAEL= 

10 

mg/kg/day

UFA= 10x

UFH= 10x

FQPA SF= 1x 

Residential LOC 

for MOE = 100

13 Week Subchronic Toxicity - Dog

LOAEL = 40 mg/kg/day based on decreased

body weight gains and food efficiency along 

with hematological and clinical chemistry 

changes.
Page 19 of 30

Table 4. Toxicological Doses and Endpoints for Halosulfuron-Methyl for Dietary and Non-Occupational 

Human Health Risk Assessments.

Exposure/

Scenario

Point of 

Departure

Uncertainty/

FQPA Safety 

Factors

RfD, PAD, 

Level of 

Concern for 

Risk 

Assessment

Study and Toxicological Effects

Cancer Classification: "not likely to be carcinogenic to humans" by the oral route, based on no 

evidence of carcinogenicity from studies in rats and mice. +

NOAEL = no observed adverse effect level. LOAEL = lowest observed adverse effect level. UF = uncertainty 

factor. UFA = extrapolation from animal to human (inter-species). UFH = potential variation in sensitivity among 

members of the human population (intra-species). FQPA SF = FQPA Safety Factor. PAD = population adjusted 

dose (a = acute, c = chronic). RfD = reference dose. MOE = margin of exposure. LOC = level of concern. N/A = 

not applicable.

A 75% dermal absorption factor should be used in route-to-route extrapolation for the intermediate term dermal 

exposure risk. Absorption via the inhalation route is presumed to be equivalent to oral absorption.

Table 5. Summary of Toxicological Doses and Endpoints for Halosulfuron-Methyl for Occupational Human 

Health Risk Assessments.

Exposure/

Scenario

Point of 

Departure

(mg/kg/day)

Uncertainty 

Factors

Level of Concern 

for Risk 

Assessment

Study and Toxicological Effects

Dermal ShortTerm (1-30 

days)

NOAEL= 

100 

UFA= 10x

UFH= 10x

Occupational LOC 

for MOE = 100

21-Day Dermal Toxicity Study - Rat

LOAEL = 1000 mg/kg/day based on 

decreased body weight gain in males.

Dermal 

IntermediateTerm (1-6 

months)

NOAEL=10 

+

UFA= 10x

UFH= 10x

Occupational LOC 

for MOE = 100

13 Week Subchronic Toxicity - Dog

LOAEL = 40 mg/kg/day based on 

decreased body weight gains and food 

efficiency along with hematological and 

clinical chemistry changes.

Inhalation 

Short-Term (1-

30 days)

NOAEL=50 UFA= 10x

UFH= 10x

Occupational LOC 

for MOE = 100

Developmental Toxicity – Rabbit

LOAEL = 150 mg/kg/day based on 

decreased body weight gain, food 

consumption, and food efficiency 

(maternal toxicity).

Inhalation 

Intermediateterm (1-6 

months)

NOAEL= 

10 

UFA= 10x

UFH= 10x

Occupational LOC 

for MOE = 100

13 Week Subchronic Toxicity - Dog

LOAEL = 40 mg/kg/day based on 

decreased body weight gains and food 

efficiency along with hematological and 

clinical chemistry changes.

Cancer Classification: "not likely to be carcinogenic to humans" by the oral route, based on no 

evidence of carcinogenicity from studies in rats and mice. +

NOAEL = no observed adverse effect level. LOAEL = lowest observed adverse effect level. UF = uncertainty 

factor. UFA = extrapolation from animal to human (intra-species). UFH = potential variation in sensitivity among 

members of the human population (inter-species). MOE = margin of exposure. LOC = level of concern. 

A 75% dermal absorption factor should be used in route-to-route extrapolation for the intermediate term dermal 

exposure risk. Absorption via the inhalation route is presumed to be equivalent to oral absorption.
Page 20 of 30

Attachment 4

Residential Exposure Tables

Table 6. Summary of Residential Use Patterns, Formulations, and Application Rates for HalosulfuronMethyl.

Registered 

Product Formulation 1 Application 

Equipment Use Sites

Maximum 

Application Rate Combined 

MOE 2

DP# 

Reference EPA Reg. No. % ai by weight lb ai/A

228-702 WDG 75%

Handheld 

Sprayers

Commercial, 

Industrial, 

Residential

Areas

0.125 --- NA3

228-711 WDG 75% 0.125 --- NA3

2749-528 WDG 75% 0.125 --- NA3

74530-34 WDG 75% 0.0625 20,000 278588

81880-1 WDG 75% 0.125 --- NA3

81880-6 WDG 12.5% 0.0625 20,000 278588

81880-14 WDG 75% 0.0625 20,000 278588

81880-17 WDG 75% 0.11 --- NA3

81880-19 WDG 75% 0.0625 20,000 278588

81880-22 WDG 75% 0.0625 20,000 278588

81880-23 WDG 10% 0.0625 20,000 278588

81880-24 WDG 5% 0.14 --- NA3

81880-26 WDG 66.2% 0.0621 covered 278588 1 WDG = water-dispersible granular. 2 --- = not assessed. Covered = Previous assessment is protective of this use pattern and application rate. 3 Not applicable.

Table 7. Residential Post-Application Exposure Scenarios for Halosulfuron-Methyl.

Pest/Use Site

Application 

Equipment

Formulation 

Type(s) 1

Registered 

Application Rate Post-Application MOEs 2 DP 

Barcode

lb ai/A

Commercial, 

Industrial, 

Residential Areas

Handheld 

Sprayers WDG

0.0625

Adults: ST: 7,000

IT: 1,800 278588

Children: ST: 3,200,000

IT: 1,100 278588

0.0621 covered 278588

0.11 --- NA3

0.125 --- NA3

0.14 --- NA3

1 WDG = water-dispersible granular. 2 --- = not assessed. Covered = Previous assessment is protective of this use pattern and application rate.
Page 21 of 30

Attachment 5

Occupational Exposure Tables

Table 8. Occupational Exposure Scenarios for Halosulfuron-Methyl.1

Crop/Use Site

Application 

Equipment Formulation 2

Maximum 

Registered 

Application 

Rate

lb ai/A

Scenario Combined MOE 3

Mixer/

Loader

Applicator Flagger4

DP

Barcode

Agricultural Uses – RACs

Alfalfa

ground WDG 0.047 ST: 11,000

IT: 1,500

ST: 48,000

IT: 6,600 --- 331645

aerial WDG 0.047 ST: 1,800

IT: 250

ST: 24,000

IT: 3,300 --- 331645

Apple

ground WDG 0.094 ST: 14,000

IT: 1,900

ST: 60,000

IT: 8,300 --- 367060

handheld WDG 0.094 ST: 4,800

IT: 650 --- 367060

aerial WDG 0.094 --- --- --- ---

airblast WDG 0.094 --- --- --- ---

Asparagus

ground WDG 0.07 ST: 11,000

IT: 2,100

ST: 51,000

IT: 10,000 --- 273929

backpack WDG 0.07 ST: 640

IT: 130 --- 273929

aerial WDG 0.07 --- --- --- ---

Bushberry 

(Subgroup 13B)

ground WDG 0.047 ST: 28,000

IT: 3,700

ST: 120,000

IT: 17,000 --- 367060

handheld WDG 0.047 ST: 9,300

IT: 1,300 --- 367060

aerial WDG 0.047 --- --- --- ---

airblast WDG 0.047 --- --- --- ---

Corn (Field)

ground WDG 0.063 ST 5,600

IT 1,100

ST 26,000

IT 5,300 --- 265726

aerial WDG 0.063 ST 940

IT 190

ST 12,000

IT 2,400 --- 265726

soil WDG 0.47 --- --- --- ---

Corn

(Sweet, Pop)

ground WDG 0.063 ST: 12,000

IT: 2,400

ST: 56,000

IT: 11,000 --- 251257

aerial WDG 0.063 ST: 2,800

IT: 560

ST: 36,000

IT: 16,000 --- 251257

Cotton

ground WDG 0.0625 ST: 12,000

IT: 2,400

ST: 56,000

IT: 11,000 --- 251257

backpack WDG 0.0625 ST: 2,800

IT: 560

ST: 36,000

IT: 16,000 --- 251257

aerial WDG 0.0625 --- --- --- ---
Page 22 of 30

Table 8. Occupational Exposure Scenarios for Halosulfuron-Methyl.1

Crop/Use Site

Application 

Equipment Formulation 2

Maximum 

Registered 

Application 

Rate

lb ai/A

Scenario Combined MOE 3

Mixer/

Loader

Applicator Flagger4

DP

Barcode

Nut, Tree

(Crop Group 14)

ground WDG 0.063 ST: 12,000

IT: 2,400

ST: 56,000

IT: 11,000 --- 251257

aerial WDG 0.063 ST: 2,800

IT: 560

ST: 36,000

IT: 16,000 --- 251257

airblast WDG 0.063 --- --- --- ---

Okra

ground WDG 0.047 ST: 28,000

IT: 3,700

ST: 120,000

IT: 17,000 --- 367060

handheld WDG 0.047 ST: 9,300

IT: 1,300 --- 367060

aerial WDG 0.047 --- --- --- ---

airblast WDG 0.047 --- --- --- ---

Pea and Bean, 

Dried Shelled, 

Except Soybean 

(Subgroup 6C)

ground WDG 0.047 ST: 28,000

IT: 3,700

ST: 120,000

IT: 17,000 --- 367060

handheld WDG 0.047 ST: 9,300

IT: 1,300 --- 367060

aerial WDG 0.047 --- --- --- ---

Pea and Bean, 

Succulent 

Shelled 

(Subgroup 6B)

ground WDG 0.023 ST: 56,000

IT: 7,600

ST: 250,000

IT: 34,000 --- 367060

aerial WDG 0.023 --- --- --- ---

Rhubarb

ground WDG 0.047 ST: 28,000

IT: 3,700

ST: 120,000

IT: 17,000 --- 367060

handheld WDG 0.047 ST: 9,300

IT: 1,300 --- 367060

aerial WDG 0.047 --- --- --- ---

Rice

ground WDG 0.063 ST: 12,000

IT: 2,400

ST: 56,000

IT: 11,000 --- 251257

aerial WDG 0.063 ST: 2,800

IT: 560

ST: 36,000

IT: 16,000 --- 251257

Sorghum, Grain 

(Milo)

ground WDG 0.047 ST: 110,000

IT: 22,000

ST: 76,000

IT: 15,000 --- 223266

aerial WDG 0.047 --- --- --- ---

Soybean

ground WDG 0.062 ST: 8,400

IT: 1,100

ST: 36,000

IT: 5,000 --- 359456

aerial WDG 0.062 ST: 1,400

IT: 190

ST: 18,000

IT: 2,500

ST: 28,000

IT: 

3,800

359456

Sugarcane

ground WDG 0.063 ST: 12,000

IT: 2,400

ST: 56,000

IT: 11,000 --- 251257

aerial WDG 0.063 ST: 2,800

IT: 560

ST: 36,000

IT: 16,000 --- 251257

Vegetable, 

Cucurbit ground WDG 0.047 ST: 26,000IT: 3,600

ST: 120,000

IT: 16,000 --- 278588
Page 23 of 30

Table 8. Occupational Exposure Scenarios for Halosulfuron-Methyl.1

Crop/Use Site

Application 

Equipment Formulation 2

Maximum 

Registered 

Application 

Rate

lb ai/A

Scenario Combined MOE 3

Mixer/

Loader

Applicator Flagger4

DP

Barcode

(Crop Group 9) aerial WDG 0.047 --- --- --- ---

Vegetable, 

Fruiting

(Crop Group 8)

ground WDG 0.047 ST: 26,000

IT: 3,600

ST: 120,000

IT: 16,000 --- 278588

aerial WDG 0.047 --- --- --- ---

Vegetable, 

Tuberous and 

Corm

(Subgroup 1C)

ground WDG 0.047 ST: 28,000

IT: 3,700

ST: 120,000

IT: 17,000 --- 367060

aerial WDG 0.047 --- --- --- ---

Non-Agricultural Uses

Non-Crop Areas 

(airports, 

cemeteries, 

fallow non-crop 

areas, golf 

courses, 

landscaped areas, 

public recreation 

areas, residential 

property, 

roadsides, school 

grounds, sod or 

turf seed farms, 

sports fields, 

residential and 

commercial 

landscaped areas 

with established 

woody

ornamentals, 

fairgrounds, race 

tracks, tennis 

courts, 

campgrounds 

and rights-of 

way)

Garden 

Hose WDG 0.062 ST: 20,000 --- 278588

Roadsides, 

Rights-of-Way, 

Tank Farms, 

Lumberyards, 

Fuel Storage 

Areas, Fallow 

Land, Fence 

Rows

Handheld WDG 0.14 --- --- ---
Page 24 of 30

Table 8. Occupational Exposure Scenarios for Halosulfuron-Methyl.1

Crop/Use Site

Application 

Equipment Formulation 2

Maximum 

Registered 

Application 

Rate

lb ai/A

Scenario Combined MOE 3

Mixer/

Loader

Applicator Flagger4

DP

Barcode

Turfgrass, 

Ornamentals, 

Fallow Ground

Handheld WDG 0.14 --- --- ---

1 The toxicological endpoint for short-term dermal exposure was changed since some calculations were done; calculations done 

before the toxicological endpoint was revised must be redone. 2 WDG = water dispersible granule. 3 MOE = margin of exposure. --- = not assessed. Bold numbers indicate that calculations do not include inhalation exposure 

(only dermal). Handheld equipment calculations are based on mixer/loader/applicator scenarios with glove PPE mitigation. 

Aerial equipment calculations are based on closed cab engineering control mitigation. Other scenarios calculated at baseline. 4

 Aerial applications are not shaded.
Page 25 of 30

Table 9. Occupational Post-Application Exposure Scenarios for Halosulfuron-Methyl.

Use Site

(TC Group)

Activity

Current

Dermal 

TC

Assessed 

TC 1 DFR 2 Dermal MOE 3

DP 

Barcode 4

Alfalfa

(field/row crops, 

low/medium)

irrigation 1,900 1,500 0.11 ST: 5,500

IT: 740 331645

scouting 1,100 100 0.11 ST: 83,000

IT: 11,000

Apple

(trees, fruit, deciduous)

thinning 3,600

--- --- --- ---

hand harvesting 1,400

scouting, hand pruning, 

training 580

transplanting 230

hand weeding, propping, 

orchard maintenance 100

Asparagus

(vegetables, stem/stalk)

irrigation 1,900 1,000 --- 600

273929

harvesting 1,100

transplanting 230 500 --- 1,300

scouting 210

300 --- 2,100 hand weeding 70

Bushberry

(Subgroup 13B)

(berry, low)

irrigation 1,900

500 0.11 ST: 17,000

IT: 2,200 367060

hand harvesting, scouting 1,100

transplanting 230

scouting 210

hand weeding, canopy 

management 70

Corn (field)

(field/row crops, tall)

irrigation 1,900

--- --- --- ---

scouting 1,100

scouting 210

hand weeding 70

Corn (sweet/pop)

(field/row crops, tall)

detasseling, hand 

harvesting 17,600

irrigation 1,900 --- --- --- 251257

scouting 1,100
Page 26 of 30

Table 9. Occupational Post-Application Exposure Scenarios for Halosulfuron-Methyl.

Use Site

(TC Group)

Activity

Current

Dermal 

TC

Assessed 

TC 1 DFR 2 Dermal MOE 3

DP 

Barcode 4

scouting 210

hand weeding 70

Cotton

(field/row crops, 

low/medium)

scouting 210

--- --- --- 251257

hand weeding 70

Nut, Tree

(Crop Group 14)

(tree, “nut”)

scouting 580

--- --- --- 251257

transplanting 230

mechanical harvesting 190

poling, orchard 

maintenance 100

Okra

(vegetable, fruiting)

irrigation 1,900

--- --- --- ---

hand harvesting, 

tying/training 1,100

transplanting 230

scouting 210

hand weeding 70

Pea and Bean, Dried 

Shelled, Except 

Soybean (Subgroup 6C)

(field/row crops, 

low/medium)

irrigation 1,900

100 0.11 ST: 83,000

IT: 11,000 367060

scouting 1,100

Pea and Bean, 

Succulent Shelled 

(Subgroup 6B)

(field/row crops, 

low/medium)

irrigation 1,900

--- --- --- ---

hand harvesting 1,100

scouting 210

hand weeding 70

Rhubarb

(vegetable, leafy)

irrigation 1,900

--- --- --- ---

hand harvesting 1,100

transplanting 230

scouting 210

hand weeding 70

Rice scouting 1,100 --- --- --- 251257
Page 27 of 30

Table 9. Occupational Post-Application Exposure Scenarios for Halosulfuron-Methyl.

Use Site

(TC Group)

Activity

Current

Dermal 

TC

Assessed 

TC 1 DFR 2 Dermal MOE 3

DP 

Barcode 4

(field/row crops, 

low/medium) hand weeding 70

Sorghum, Grain (milo)

(field/row crops, 

low/medium)

scouting 210

1,000 0.11 ST: 4,500

IT: 910 223266

hand weeding 70

Soybean

(field/row crops, 

low/medium)

scouting 1,100 1,500 0.14 ST: 4,200

IT: 560 359456

hand weeding 70 100 0.14 ST: 63,000

IT: 8,400

Sugarcane

(sugarcane)

hand harvesting 17,600

scouting 1,100 --- --- --- 251257

hand weeding 70

Vegetable, Cucurbit

(Crop Group 9)

(vegetable, cucurbit)

irrigation 1,900

--- --- --- ---

hand harvesting, turning, 

training, assisted 

mechanical harvesting

550

transplanting 230

scouting, hand weeding, 

hand pruning, thinning 

fruit

90

Vegetable, Fruiting

(Crop Group 8)

(vegetable, fruiting)

irrigation 1,900

1,000 0.11 ST: 8,300

IT: 1,100

278588

hand harvesting, 

tying/training 1,100

hand harvesting, 

tying/training 550

transplanting 230

500 0.11 ST: 17,000

IT: 2,200

scouting 210

hand pruning, scouting, 

hand weeding, thinning 

fruit

90

hand weeding, hand 

pruning 70

Vegetable, Tuberous 

and Corm

(Subgroup 1C)

(vegetable, “root”)

irrigation 1,900

1,500 0.11 ST: 5,500

IT: 740 hand harvesting 1,100 367060

scouting 210 300 0.11 ST: 28,000
Page 28 of 30

Table 9. Occupational Post-Application Exposure Scenarios for Halosulfuron-Methyl.

Use Site

(TC Group)

Activity

Current

Dermal 

TC

Assessed 

TC 1 DFR 2 Dermal MOE 3

DP 

Barcode 4

hand weeding 70 IT: 3,700

Non-Agricultural Uses

Non-Crop Areas, 

Turfgrass

(turf/sod)

maintenance, slab 

harvesting, 

transplanting/planting, roll 

harvesting

6,700 --- --- ---

278588

maintenance 3,700 --- --- ---

Ornamentals

(unassigned)

irrigation 1,900 --- --- ---

278588

hand harvesting, hand 

pruning, scouting, 

container moving, hand 

weeding, transplanting, 

grafting, propagating, 

pinching, tying/training

230 --- --- ---

1 --- = not assessed. 2 DFR = dislodgeable foliar residue. 3 MOE = margin of exposure. 4 DP# D251257 did not assess any post-application exposure estimates because “based on the timing of application (preemergent or postemergent during early stages of plant growth), there is expected to be minimal dermal contact with residue on 

foliage.”
Page 29 of 30

Attachment 6

Outstanding Deficiencies to be Addressed by the Registrants

Data Requirements 

Toxicology

870.7800 Immunotoxicity

● An immunotoxicity study is required under 40 CFR §158.500.

Residue Chemistry

860.1650 Submittal of Analytical Reference Standards

● Analytical reference standards are available for halosulfuron-methyl and the 3-CSA (3-

chlorosulfonamide acid) metabolite but not for the rearrangement ester (RRE) of 

halosulfuron-methyl (e-mail from C. Stafford, ACB/BEAD, 11/16/11). An analytical 

reference standard for the rearrangement ester (RRE) of halosulfuron-methyl must be 

submitted to the EPA National Pesticide Standards Repository. 

Occupational and Residential Exposure

None.
Page 30 of 30

Label Amendments

In connection with D366410: 

860.1200 Directions for Use

● For Crop Subgroup 6B (pea and bean, succulent shelled), the label for Sandea®

Herbicide (EPA Reg. No. 81880-18) should be amended to prohibit applications to 

legumes grown for livestock feeds because no residue data are available for cowpea 

forage and hay. The statement “Do not apply to cowpea used for livestock feed” should 

be added instead of the statement “Do not feed to livestock”.

● For Crop Subgroup 13-07B (bushberry), the label for Sandea® Herbicide (EPA Reg. No.

81880-18) should be amended to remove the instructions pertaining to the use of a nonionic surfactant. If it is IR-4’s intention to add a nonionic surfactant when Sandea® 

Herbicide is applied to these crops, then additional field trial data are required.