UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON, D.C. 20460 

OFFICE OF CHEMICAL SAFETY 

AND POLLUTION PREVENTION 

MEMORANDUM 

Date: l 5-SEP-2015 

SUBJECT: Sulfometuron Methyl. Draft Human Health Risk Assessment in Support of 

Registration Review. 

PC Code: 12200 I 

MRID No.: NA 

Petition No.: NA 

DP Barcode: 0 427028 

Registration No.: NA 

Regulatory Action: Regisrration Review 

Risk Assessment Type: NA Case No.: 3136 

TXR No.: NA CAS No.: 74222-97-2 

FROM: 

THRU: 

TO: 

Sara

Kelly 

h J

M. 

. L

Lowe

evy, Chemist 

, Environmental Scientist -::?«-e. ~ 

Monique M. Perron, Sc.D., Toxicologist ~ ;17~ 

Risk Assessment Branch l (RABI) 

Health Effects Division (HED: 7509P) 

Thurston G. Morton, Acting Branch hief ~ George F. Kramer, Ph.D., Senior Chemist ~:iiiilll~+-,r::~-'o::-::?--

RAB l/HED (7509P) 

Caitlin Newcamp 

Pesticide Re-evaluation Division (PRD; 7508P) 

As part of Registration Review, PRO of the Office of Pesticide Programs (OPP) has requested 

that HED evaluate the hazard and exposure data, and conduct occupational and residential 

exposure assessments, as needed, to estimate the risk to human health that will result from the 

currently registered uses of pesticides. This memorandum serves as HED's draft human health 

risk assessment of the dietary, occupational and residential exposure, and aggregate risk from the 

registered uses of sulfometuron methyl. 

Since the last human health risk assessment (W. Brinon el al.; 20-DEC-2007; D346064) and 

scoping document (W. Britton el al.; 08-NOY-2012; 0402498), the following updates have been 

incorporated for sulfometuron methyl. 

• The subchronic inhalation, imrnunotoxicity, and neurotoxicity (acute and subchronic) 

study requirements have been waived. 

• The acute dietary endpoint has been removed, and an incidental oral endpoint for spray 

drift assessment has been added. 

• The occupational risk assessment has been updated to incorporate new science policies. 

Page I of32 
Sulfometuron methyl Draft Human Health Risk Assessment 0427028 

• A high-end drinking water exposure value was used to assess screening-level dietary 

exposure/risk estimates. 

Page 2 of32 
Sulfometuron methyl Draft Human Health Risk Assessment D427028

Page 3 of 32

Table of Contents

1.0 Executive Summary ................................................................................................................................ 4

2.0 HED Recommendations.......................................................................................................................... 5

2.1 Tolerance Considerations...........................................................................................................5

2.2 Label Considerations .................................................................................................................5

3.0 Ingredient Profile .................................................................................................................................... 6

3.1 Chemical Identity and Physical/Chemical Properties................................................................6

3.2 Use Pattern.................................................................................................................................6

3.3 Anticipated Exposure Pathways.................................................................................................6

3.4 Consideration of Environmental Justice ....................................................................................6

4.0 Hazard Identification/Toxicology ........................................................................................................... 7

4.1 Summary of Toxicological Effects............................................................................................7

4.2 Safety Factor for Infants and Children (FQPA SF) ...................................................................7

4.3 Toxicity Endpoint and Point of Departure Selections................................................................7

4.4 Endocrine Disruption.................................................................................................................9

5.0 Dietary Exposure and Risk Assessment................................................................................................ 10

5.1 Water Residue Profile ..............................................................................................................10

5.2 Dietary Exposure and Risk Estimates......................................................................................11

6.0 Residential (Non-Occupational) Exposure and Risk Assessment......................................................... 12

6.1 Spray Drift ...............................................................................................................................12

6.1.1 Combined Risk Estimates from Lawn Deposition Adjacent to Applications..........12

6.2 Residential Bystander Post-Application Inhalation Exposure .................................................13

7.0 Aggregate Exposure and Risk Assessment........................................................................................... 13

8.0 Cumulative Exposure/Risk Characterization ........................................................................................ 13

9.0 Occupational Exposure/Risk Characterization ..................................................................................... 13

9.1 Occupational Handler Exposure/Risk Estimates .....................................................................13

9.2 Occupational Post-application Exposure/Risk Estimates ........................................................17

Appendix A: Chemical Identity Tables. .................................................................................................... 20

Appendix B: Sulfometuron Methyl Acute, Subchronic, and Chronic Toxicity Profile............................. 21

Appendix C: Registered Sulfometuron Methyl Use Patterns .................................................................... 24

Appendix D: Dietary Exposure/Risk Modeling Input and Output............................................................. 27

Appendix E. Review of Human Research ................................................................................................. 28

Appendix F. Occupational Non-cancer Algorithms.................................................................................... 29

Appendix G. Spray Drift Detailed Description........................................................................................... 31
Sulfometuron methyl Draft Human Health Risk Assessment D427028

Page 4 of 32

1.0 Executive Summary

Sulfometuron methyl [methyl 2-[[[[(4,6-dimethyl-2-pyrimidinyl)amino]carbonyl]amino]

sulfonyl]benzoate], is a sulfonylurea (SU) herbicide that provides broad spectrum pre- and postemergence control of annual and perennial grasses and broad-leaf weeds in forestry/Christmas 

trees and non-agricultural situations, including vegetative management of rights-of-way and 

railroads. Similar to other SU herbicides, sulfometuron methyl’s mode of action involves 

inhibiting the activity of the enzyme acetolactate synthase (ALS), which inhibits the production 

of amino acids required for cell growth in plants. 

The toxicity database for sulfometuron methyl is adequate to support current registration 

requirements; currently, no additional toxicological studies are required. Subchronic inhalation, 

immunotoxicity, and neurotoxicity (acute and subchronic) studies are not available for 

sulfometuron methyl, as required in accordance with the current 40 CFR Part 158 Toxicology 

Data Requirements. However, the Hazard and Science Policy Council (HASPOC) determined 

that these studies are not required at this time for sulfometuron methyl (K. Rury; 02-AUG-2012; 

TXR#0056431 and K. Rury; 06-AUG-2013; TXR#0056723). The latest risk assessment was 

conducted as part of the Reregistration Eligibility Decision (RED) document (W. Britton; 20-

DEC-2007; D346064). No new toxicity and/or metabolism data have been received. There have 

been no changes to the prior dose-response assessment except for the removal of the acute 

dietary endpoint and addition of an incidental oral endpoint for spray drift assessment. 

For dietary exposure, HED has conducted a screening-level chronic dietary risk assessment for 

sulfometuron methyl using a SU-class-wide screening-level estimate of residues in drinking 

water. Since sulfometuron methyl is a non-food use chemical, residues in food are not 

anticipated, and the dietary assessment includes only drinking water. Dietary risk estimates 

range from 2.7 to 9.7% of the chronic reference dose (cRfD) and are well below HED’s level of 

concern (LOC). HED did not conduct an acute or cancer dietary exposure/risk assessment due to 

the lack of an appropriate endpoint for acute dietary assessment, and sulfometuron methyl is not 

likely to be a carcinogen, respectively.

There are no registered residential uses or uses resulting in direct residential exposure associated 

with sulfometuron methyl. Therefore, a quantitative residential exposure assessment was not 

performed. 

Sulfometuron methyl can be applied via groundboom equipment and, therefore, there is the 

potential for indirect exposure to sulfometuron methyl related to spray drift. As a result, dermal 

risk estimates for adults and combined dermal plus incidental oral risk estimates for children 1 to 

<2 years old were calculated. Both children (1 to <2 years old) combined risk estimates, and 

adult dermal risk estimates result in no risks of concern at the field edge for groundboom 

applications (screening level assumptions for spray type/nozzle configuration). All MOEs are >

the LOC of 100.

In the case of sulfometuron methyl, aggregate exposure and risk estimates are equivalent to the 

dietary exposure and risk estimates, and do not exceed HED’s LOC.

The occupational handler exposure and risk assessment indicates that for all scenarios, combined 

dermal + inhalation risk estimates were not of concern (i.e., MOEs > 100) with either baseline 

protection (long-sleeved shirt, long pants, shoes plus socks, no gloves or respirator) or with the 
Sulfometuron methyl Draft Human Health Risk Assessment D427028

Page 5 of 32

use of gloves, as recommended on certain labels. PRD should ensure the appropriate personal 

protective equipment (PPE) is listed on registered labels.

 

Occupational exposures to workers re-entering sulfometuron methyl-treated non-agricultural 

areas are not anticipated because contact with previously treated areas is unlikely. However, 

there is a potential for post-application exposure from the registered forestry/Christmas tree use; 

therefore, a quantitative post-application assessment was conducted for that use. Short- and 

intermediate-term dermal post-application risk estimates are not a concern for the 

forestry/Christmas tree use on the day of application (i.e., all MOEs ≥ 100).

Sulfometuron methyl is classified as Toxicity Category III via the dermal route and for eye 

irritation potential, and Toxicity Category IV for dermal irritation potential. It is not a skin 

sensitizer. Under 40 CFR 156.208 (c) (2), ai’s classified as Toxicity Category III or IV for acute 

dermal, eye irritation and primary skin irritation are assigned a 12-hour Restricted Entry Interval 

(REI). Therefore, the [156 subpart K] Worker Protection Statement REI of 12 hours is adequate 

to protect agricultural workers from post-application exposures to sulfometuron methyl. The 

occupational post-application assessment indicated no risks of concern on the day of application 

as well; therefore, HED recommends a 12-hour REI for the sulfometuron methyl labels. 

It is noted that several of the registered sulfometuron methyl labels require either a 4-hour or a 

48-hour REI. For some of the labels, multiple active ingredients are included in the end-use 

product, and these additional active ingredients may require a longer REI. REIs may be further 

reduced if certain criteria are met in accordance with the Pesticide Registration (PR) Notice 95-3 

[Reduction of WPS Interim REIs for Certain Low Risk Pesticides]1. Upon review of the criteria 

for the active ingredient only, it appears that sulfometuron methyl is consistent with the criteria 

in PRN 95-3 that allow for a 4-hour REI. Note: The PR Notice also includes similar criteria for 

the end-use product. These criteria have not been evaluated by HED. 

2.0 HED Recommendations

HED has not identified any risk concerns associated with the registered uses of sulfometuron 

methyl. There are no data gaps that would require submission of additional toxicity, residue 

chemistry, or exposure data. Sulfometuron methyl is a non-food use chemical; therefore, there 

are no tolerances. No label changes are required at this time.

2.1 Tolerance Considerations

Sulfometuron methyl is a non-food use chemical; therefore, there are no tolerances.

2.2 Label Considerations

There are no label recommendations for registered products containing sulfometuron methyl. A 

summary of the occupational risk estimates has been provided, and shows that there are no risk 

estimates of concern for registered uses of sulfometuron methyl assuming either baseline 

protection (long-sleeved shirt, long pants, shoes plus socks, no gloves or respirator) or with the 

use of gloves, as recommended on certain labels. The occupational post-application assessment 

indicated no risks of concern on the day of application as well; therefore, HED recommends a 

12-hour REI for the sulfometuron methyl labels. Upon review of the 4-hr REI criteria for the 

 

1 Available: http://www.epa.gov/PR_Notices/pr95-3.html
Sulfometuron methyl Draft Human Health Risk Assessment D427028

Page 6 of 32

active ingredient only, it appears that sulfometuron methyl is consistent with the criteria in PRN 

95-3 that allow for a 4-hour REI. Note: The PR Notice also includes similar criteria for the enduse product. These criteria have not been evaluated by HED. 

3.0 Ingredient Profile

3.1 Chemical Identity and Physical/Chemical Properties

The chemical structure and nomenclature of sulfometuron methyl and a detailed description of 

the physicochemical properties are provided in Appendix A. 

3.2 Use Pattern

Sulfometuron methyl is used to control annual and perennial broadleaf weeds and grasses in 

forestry/Christmas trees and non-agricultural sites (i.e., rights of way, non-crop industrial sites, 

and unimproved turf). All sulfometuron-methyl-containing products are formulated as waterdispersible granules (WDGs). Applications of sulfometuron methyl can be made aerially by 

fixed-wing airplane and helicopter, and by groundboom or hand-held equipment. Additionally, 

sulfometuron methyl can be used to impregnate or coat dry bulk fertilizer for application to 

forested areas. Maximum application rates are 0.281 lb ai/A, and 0.053 lb ai/gal or 0.00281 lb 

ai/gal depending on the use site. PPE recommended on registered labels typically includes longsleeved shirts, long pants, and socks, with some labels also recommending the use of chemicalresistant gloves and protective eyewear. REIs range from 4 hours to 48 hours, depending on the 

product. Several products contain multiple active ingredients; however, this assessment only 

pertains to sulfometuron methyl. A summary of the registered uses are included in Appendix C.

3.3 Anticipated Exposure Pathways

Based on the registered application scenarios, dietary exposure is an anticipated exposure 

pathway as residues of sulfometuron methyl are expected to be found in drinking water. 

Although there are no registered residential uses of sulfometuron methyl, there is a potential for 

spray drift that may result in exposures in residential and non-occupational settings. In an 

occupational setting, applicators may be exposed while handling the pesticide prior to 

application, as well as during application. Occupational exposures to workers re-entering 

sulfometuron methyl non-agricultural treated areas are not anticipated because contact with 

previously treated areas is unlikely; however, post-application exposure is anticipated from the 

registered forestry/Christmas tree use. This risk assessment considers all of the aforementioned 

exposure pathways based on the existing uses of sulfometuron methyl.

3.4 Consideration of Environmental Justice 

Potential areas of environmental justice concerns, to the extent possible, were considered in this 

human health risk assessment, in accordance with U.S. Executive Order 12898, "Federal Actions 

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

(http://epa.gov/compliance/ej/resources/policy/exec_order_12898.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 United States 
Sulfometuron methyl Draft Human Health Risk Assessment D427028

Page 7 of 32

Department of Agriculture (USDA) under the National Health and Nutrition Examination 

Survey, What We Eat in America, (NHANES/WWEIA; 2003-2008) 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 

post-application 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.

4.0 Hazard Identification/Toxicology

The toxicology database for sulfometuron methyl, a non-food use chemical, is considered 

adequate for risk assessment. Subchronic inhalation, immunotoxicity, and neurotoxicity (acute 

and subchronic) studies are not available for sulfometuron methyl, as required in accordance 

with the current 40 CFR Part 158 Toxicology Data Requirements. However, the HASPOC 

determined that these studies are not required at this time for sulfometuron methyl (K. Rury; 02-

AUG-2012; TXR#0056431 and K. Rury; 06-AUG-2013; TXR#0056723). The TOXLINE 

(National Library of Medicine) database literature search did not identify any new toxicological 

information not already considered. The latest risk assessment was conducted as part of the RED

document (W. Britton; 20-DEC-2007; D346064). No new toxicity and/or metabolism data have 

been received. For a summary of the acute, subchronic, and chronic toxicity profile, see 

Appendix B. 

4.1 Summary of Toxicological Effects

Sulfometuron methyl has low acute toxicity via oral, dermal, and inhalation routes of exposure 

(Toxicity Category III or IV). It shows minimal eye irritation (Toxicity Category III) and is not a 

dermal irritant or sensitizer. The primary toxic effect in the toxicological database is hemolytic 

anemia in dogs. There is no evidence that sulfometuron methyl is a developmental toxicant 

based on prenatal developmental studies. Sulfometuron methyl is a non-food use chemical and 

given its limited use pattern and low likelihood for chronic durations of exposure, rodent chronic 

toxicity or carcinogenicity studies were not required. Sulfometuron methyl was negative in the 

mutagenicity/genetic toxicity studies. 

4.2 Consideration of Toxicity to Children

FQPA considerations do not apply to sulfometuron methyl for the non-food use patterns 

described in this assessment. However, the HED risk assessment team has reviewed the toxicity 

database for indications of susceptibility in the young. The toxicity database of sulfometuron 

methyl is considered adequate to assess the qualitative or quantitative susceptibility in the young. 

There is no evidence of increased susceptibility in rats or rabbits and no evidence of 

neurotoxicity.

4.3 Toxicity Endpoint and Point of Departure Selections
Sulfometuron methyl Draft Human Health Risk Assessment D427028

Page 8 of 32

There have been no changes to the prior dose-response assessment except for the removal of the 

acute dietary endpoint and addition of an incidental oral endpoint for spray drift assessment. 

Previously, the chronic oral toxicity study in dogs was used to evaluate acute dietary exposures; 

however, the effects seen in the study are not considered to be attributable to a single dose. 

Although abortions were noted in the rabbit developmental range-finding study, the effect was 

only seen at or near the limit dose following repeated dosing; therefore, the effect is not 

considered to be due to a single dose. As a result, an endpoint was not selected to evaluate acute 

dietary exposures.

It is recognized that the studies in the sulfometuron methyl database, including those used for 

endpoint selection, have not been updated to reflect current policy, and may be considered 

conservative. The currently selected points of departure (PODs) are protective of the effects 

observed in the sulfometuron methyl database and any updates would not impact the overall 

findings of the risk assessment given the current risk picture for sulfometuron methyl. 

Table 4.3.1. Summary of Toxicological Doses and Endpoints for Sulfometuron Methyl for Use in Dietary and 

Non-Occupational Human Health Risk Assessments.

Exposure 

Scenario POD

Uncertainty/

FQPA SFs

RfD, LOC for Risk 

Assessment Study and Toxicological Effects

Acute Dietary 

(All 

populations)

A dose and endpoint of concern attributable to a single dose was not observed.

Chronic Dietary 

(All 

Populations)

NOAEL = 27.5 

mg/kg/day

UFA = 10X

UFH = 10X

cRfD = 0.275 

mg/kg/day

Chronic Oral Toxicity Study (dog)

LOAEL = 148.5 mg/kg/day based 

on decreases in body weight gain 

in males, hemolytic anemia, and a 

slight increase in alkaline 

phosphatase in both sexes.

Incidental oral 

(short- and 

intermediateterm)

NOAEL = 27.5 

mg/kg/day

UFA = 10X

UFH = 10X Residential LOC for 

MOE <100

Chronic Oral Toxicity Study (dog)

LOAEL = 148.5 mg/kg/day based 

on decreases in body weight gain 

in males, hemolytic anemia, and a 

slight increase in alkaline 

phosphatase in both sexes.

Dermal 

exposure (shortand 

intermediateterm)

NOAEL = 27.5 

mg/kg/day

Dermal 

absorption 

factor = 100%

UFA = 10X

UFH = 10X Residential LOC for 

MOE <100

Chronic Oral Toxicity Study (dog)

LOAEL = 148.5 mg/kg/day based 

on decreases in body weight gain

in males, hemolytic anemia, and a 

slight increase in alkaline 

phosphatase in both sexes.

Cancer (oral, 

dermal, 

inhalation)

Given the limited use pattern and low likelihood for chronic durations of exposure for this 

compound, carcinogenicity studies were not required.

Point of departure (POD) = A data point or an estimated point that is derived from observed dose-response data and used to mark 

the beginning of extrapolation to determine risk associated with lower environmentally relevant human exposures. NOAEL = 

no-observed adverse-effect level. LOAEL = lowest-observed adverse-effect level. UF = uncertainty factor. UFA = extrapolation 

from animal to human (interspecies). UFH = potential variation in sensitivity among members of the human population 

(intraspecies). RfD = reference dose (a = acute, c = chronic). MOE = margin of exposure. LOC= level of concern.
Sulfometuron methyl Draft Human Health Risk Assessment D427028

Page 9 of 32

Table 4.3.2. Summary of Toxicological Doses and Endpoints for Sulfometuron Methyl for Use in 

Occupational Human Health Risk Assessments.

Exposure/

Scenario POD Uncertainty Factors

LOC for Risk 

Assessment

Study and Toxicological 

Effects

Dermal 

exposure (shortand 

intermediateterm)

NOAEL = 

27.5 

mg/kg/day

Dermal 

absorption 

factor = 100%

UFA = 10X

UFH = 10X

Occupational LOC for 

MOE <100

Chronic Oral Toxicity Study 

(dog)

LOAEL = 148.5 mg/kg/day 

based on decreases in body 

weight gain in males, 

hemolytic anemia, and a slight 

increase in alkaline 

phosphatase in both sexes.

Inhalation 

exposure (shortand 

intermediateterm)

NOAEL = 

27.5 

mg/kg/day

Inhalation 

assumed 

equivalent to 

oral

UFA = 10X

UFH = 10X

Occupational LOC for 

MOE <100

Chronic Oral Toxicity Study 

(dog)

LOAEL = 148.5 mg/kg/day 

based on decreases in body 

weight gain in males, 

hemolytic anemia, and a slight 

increase in alkaline 

phosphatase in both sexes.

Cancer (oral, 

dermal, 

inhalation)

Given the limited use pattern and low likelihood for chronic durations of exposure for this 

compound, carcinogenicity studies were not required.

Point of departure (POD) = A data point or an estimated point that is derived from observed dose-response data and used to mark 

the beginning of extrapolation to determine risk associated with lower environmentally relevant human exposures. NOAEL = 

no-observed adverse-effect level. LOAEL = lowest-observed adverse-effect level. UF = uncertainty factor. UFA = extrapolation 

from animal to human (interspecies). UFH = potential variation in sensitivity among members of the human population 

(intraspecies). MOE = margin of exposure. LOC = level of concern.

4.4 Endocrine Disruption

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 for sulfometuron 

methyl, 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), sulfometuron 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 
Sulfometuron methyl Draft Human Health Risk Assessment D427028

Page 10 of 32

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. A second list of chemicals 

identified for EDSP screening was published on June 14, 20132and includes some pesticides 

scheduled for Registration Review and chemicals found in water. Neither of these lists should be 

construed as a list of known or likely endocrine disruptors.

For further information on the status of the EDSP, the policies and procedures, the lists of 

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

website.3

5.0 Dietary Exposure and Risk Assessment

Since sulfometuron methyl is a non-food use chemical, there are no residue chemistry data 

requirements, and the dietary exposure assessment includes only drinking water. 

5.1 Water Residue Profile

Screening groundwater-sourced drinking water exposure estimates were generated with the 

Pesticide Root Zone Model for GroundWater (PRZM-GW; v.1.07) for use in the SU dietary risk 

assessments. Rather than produce chemical-specific estimated drinking water concentrations 

(EDWCs) following the usual assessment procedures, EFED provided coarse-screen estimates 

that should exceed upper-bound, chemical-specific EDWCs for any SU. This was achieved by 

using model inputs (rate, soil mobility, persistence) from all the SU herbicides which yielded the 

highest drinking water residue estimates. The resulting coarse-screen EDWCs from PRZM-GW 

were higher than the surface water estimates and were used as conservative estimates of potential 

residues in drinking water and are summarized in Table 5.1. The chronic dietary exposure

assessment for sulfometuron methyl used the post-breakthrough mean value of 492 μg/L (0.492 

ppm). 

Table 5.1. PRZM-GW Coarse-Screen EDWCs for SUs1.

Modeled Scenario Kd or KOC

Initial Application 

Dates (days postemergence)

Max. Daily Conc. 

(μg/L)

Mean 

Breakthrough 

Time (yrs)

Postbreakthrough 

Mean (μg/L)

WI corn

Kd 7 449 11.5 415

KOC 7 504 6.9 425

DMV corn

Kd 7 489 5.3 369

KOC 7 560 3.3 378

FL citrus

Kd 7 429 3.2 351

KOC 7 467 2.3 349

FL potato

Kd 7 375 2.6 272

KOC 7 407 2.2 275

 

2 See http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPPT-2009-0477-0074 for the final second list of 

chemicals.

3 http://www.epa.gov/endo/
Sulfometuron methyl Draft Human Health Risk Assessment D427028

Page 11 of 32

Table 5.1. PRZM-GW Coarse-Screen EDWCs for SUs1.

Modeled Scenario Kd or KOC

Initial Application 

Dates (days postemergence)

Max. Daily Conc. 

(μg/L)

Mean 

Breakthrough 

Time (yrs)

Postbreakthrough 

Mean (μg/L)

GA peanut

Kd 7 197 5.2 156

KOC 7 206 3.9 158

NC cotton

Kd 7 640 8.7 492

Kd 37 641 8.7 491

Kd 67 637 8.7 490

KOC 7 742 5.7 484

KOC 37 751 5.7 483

KOC 67 744 5.7 482

1 Maximum values are bolded.

5.2 Dietary Exposure and Risk Estimates

In support of Registration Review, an updated chronic dietary exposure and risk assessment was 

conducted using Dietary Exposure Evaluation Model software with the Food Commodity Intake 

Database (DEEM-FCID), ver. 3.16, which incorporates consumption data from the USDA 

NHANES/WWEIA; 2003-2008. As noted previously, since sulfometuron methyl is a non-food 

use chemical, the dietary assessment includes only drinking water. The EDWC of 0.492 ppm 

was incorporated directly into the chronic dietary analysis as “water, direct, all sources” and 

“water, indirect, all sources.” The chronic dietary exposure estimates are well below HED’s 

LOC (<100% cRfD) for the general U.S. population and all population subgroups (see Table 

5.2). The residue file as well as the results of the chronic assessment are provided in Appendix 

D. An acute dietary assessment was not conducted for sulfometuron methyl because an endpoint 

of concern attributable to a single dose was not identified. Furthermore, a cancer dietary 

assessment was not conducted because, given the limited use pattern and low likelihood for 

chronic durations of exposure for this compound, carcinogenicity studies were not required.

Table 5.2. Summary of Dietary (Food + Drinking Water) Exposure and Risk for Sulfometuron Methyl.

Population Subgroup1

Acute Dietary

(95th Percentile) Chronic Dietary Cancer

Dietary

Exposure 

(mg/kg/day)

% aRfD

Dietary 

Exposure

(mg/kg/day)

% cRfD

Dietary 

Exposure

(mg/kg/day)

Risk

General U.S. Population

NA NA

0.010302 3.7

NA NA

All Infants (<1 year old) 0.026564 9.7

Children 1-2 years old 0.014861 5.4

Children 3-5 years old 0.012521 4.6

Children 6-12 years old 0.009030 3.3

Youth 13-19 years old 0.007513 2.7

Adults 20-49 years old 0.010278 3.7

Adults 50-99 years old 0.010161 3.7

Females 13-49 years old 0.010241 3.7

1 The value for the highest exposed population is bolded.
Sulfometuron methyl Draft Human Health Risk Assessment D427028

Page 12 of 32

6.0 Residential (Non-Occupational) Exposure and Risk Assessment

There are no registered residential uses or occupational uses resulting in residential exposure 

associated with sulfometuron methyl. Therefore, a quantitative residential exposure assessment 

was not performed.

6.1 Spray Drift

A detailed description about HED’s spray-drift policy and how to evaluate the drift potential and 

associated risks is available in Appendix G. 

6.1.1 Combined Risk Estimates from Lawn Deposition Adjacent to Applications

The spray drift risk estimates are based on an estimated deposited residue concentration as a 

result of the screening level agricultural application scenarios. The potential risk estimates from 

these residues can be calculated using drift modeling onto 50-feet wide lawns coupled with 

methods employed for residential risk assessments for turf products. Sulfometuron methyl is 

used in forestry/Christmas trees and various non-agricultural sites, and can be applied via 

groundboom and aerial equipment. The recommended drift scenario screening level options are 

listed below: 

• Groundboom applications are based on the AgDrift® option for high boom height and 

using very fine to fine spray type using the 90th percentile results. 

• Aerial applications are based on the use of AgDrift® Tier 1 aerial option for a fine to 

medium spray type and a series of other parameters which will be described in more 

detail below (e.g., wind vector assumed to be 10 mph in a downwind direction for entire 

application/drift event). 

Both children (1 to <2 years old) combined incidental oral and dermal risk estimates, and adult 

dermal risk estimates from exposure to sulfometuron methyl related to spray drift result in no 

risks of concern at the field edge for aerial and groundboom applications (screening level 

assumptions for spray type/nozzle configuration; Table 6.1.1.1). All MOEs are ≥ the LOC or 

100.

Table 6.1.1.1. Sulfometuron Methyl Risk Estimates (MOEs) Related to Indirect Exposure to Spray Drift.

Lifestage Route of 

Exposure

Application 

Type

Spray Type/ Nozzle 

Configuration

Appl. Rate 

(lb ai/A)

TTR1

(ug/cm2)

MOEs At Edge of 

the Field2

(LOC = 100)

Adults Dermal

Aerial Fine to Medium

0.281 0.031

1,000

Groundboom High Boom Very fine 

to Fine 1,400

Children 

(1 to < 2 

years)

Dermal + 

Incidental Oral

Aerial Fine to Medium 500

Groundboom High Boom Very fine 

to Fine 690

1 TTR = Application Rate × F × (1-D)t × 4.54E8 μg/lb × 2.47E-8 acre/cm2

; where F = 0.1 and D = 0.10 per day. HED’s default assumption 

that 10% of the application is available for transfer on day 0 following the application and the residues dissipate at a rate of 10% each following 

day.

2. MOE = POD (27.5 mg/kg/day) ÷ Dose (mg/kg/day). For dose algorithms and inputs, see Turf SOP of the 2012 Residential SOPs 

(http://www.epa.gov/pesticides/science/residential-exposure-sop.html).
Sulfometuron methyl Draft Human Health Risk Assessment D427028

Page 13 of 32

6.2 Residential Bystander Post-Application Inhalation Exposure

Volatilization of pesticides may be a source of post-application inhalation exposure to 

individuals nearby pesticide applications. The agency sought expert advice and input on issues 

related to volatilization of pesticides from its FIFRA Scientific Advisory Panel (SAP) in 

December 2009, and received the SAP’s final report on March 2, 2010 

(http://www.epa.gov/scipoly/SAP/meetings/2009/120109meeting.html). The agency has 

evaluated the SAP report and has developed a Volatilization Screening Tool and a subsequent 

Volatilization Screening Analysis.4 During Registration Review, the agency will utilize this 

analysis to determine if data (i.e., flux studies, route-specific inhalation toxicological studies) or 

further analyses are required for sulfometuron methyl.

7.0 Aggregate Exposure and Risk Assessment

The Food Quality Protection Act of 1996 directs EPA to assess aggregate exposure to pesticide 

chemical residues, including all anticipated dietary exposures and all other exposures for which 

there is reliable information. In the case of sulfometuron methyl, aggregate exposure and risk 

estimates are equivalent to the dietary exposure and risk estimates (in Section 5), and risk 

estimates are not of concern to HED (i.e., MOEs ≥ 100).

8.0 Cumulative Exposure/Risk Characterization

In 2015, EPA’s Office of Pesticide Programs released a guidance document entitled, Pesticide 

Cumulative Risk Assessment: Framework for Screening Analysis 

[http://www.epa.gov/oppfead1/cb/csb_page/updates/2015/framework-for-screeninganalysis.html]. This document provides guidance on how to screen groups of pesticides for 

cumulative evaluation using a two-step approach beginning with the evaluation of available 

toxicological information and if necessary, followed by a risk-based screening approach. This 

framework supplements the existing guidance documents for establishing common mechanism 

groups (CMGs)5and conducting cumulative risk assessments (CRA)6. The Agency has utilized 

this framework to evaluate the SUs of which iodosulfuron-methyl-sodium is a member (J. 

D’Agostino; D428798; 9/9/15). Although the SUs share some chemical and toxicological 

characteristics, the toxicological database does not support a testable hypothesis for a common 

mechanism of action. No further mechanistic data are required and no further cumulative 

evaluation is necessary.

9.0 Occupational Exposure/Risk Characterization

9.1 Occupational Handler Exposure/Risk Estimates

Based on current labeling, types of equipment and techniques that can potentially be used, 

occupational handler exposure is expected from the registered uses on forestry/Christmas trees

and various non-crop sites. Occupational handlers are anticipated to have short-term (1-30 days) 

and intermediate-term (1-6 months) dermal and inhalation exposures. Long-term exposures 

(more than 6 months) are not anticipated.

 

4 Available at: http://www.regulations.gov/#!docketDetail;D=EPA-HQ-OPP-2014-0219.

5 Guidance For Identifying Pesticide Chemicals and Other Substances that have a Common Mechanism of Toxicity (USEPA, 1999)

6 Guidance on Cumulative Risk Assessment of Pesticide Chemicals That Have a Common Mechanism of Toxicity (USEPA, 2002)
Sulfometuron methyl Draft Human Health Risk Assessment D427028

Page 14 of 32

In support of Registration Review, an updated occupational exposure assessment for 

sulfometuron methyl was conducted for mixers/loaders and applicators for aerial and 

groundboom applications of a WDG formulation, as well as mixer/loader/applicators performing 

spot treatments with handheld equipment. The assessment was based on the maximum 

registered application rates noted in Appendix C, and maximum area treated per day or gallons 

handled. 

Handler exposure and risk were calculated at baseline (long pants, a long-sleeved shirt, no 

chemical-resistant gloves, and no respirator) and with PPE when necessary. PPE recommended 

on registered sulfometuron methyl labels typically includes long-sleeved shirts, long pants, and 

socks, with some labels also recommending the use of chemical-resistant gloves and protective 

eyewear. 

For all scenarios, combined dermal + inhalation risk estimates were not of concern (i.e., MOEs ≥ 

100) with either baseline protection (long-sleeved shirt, long pants, shoes plus socks, no gloves,

or respirator) or with the use of gloves, as recommended on some labels (see Table 9.1.1). 
Page 15 of 32

Table 9.1.1. Summary of Occupational Handler Exposure and Risk Estimates for Sulfometuron Methyl.

Scenario Crop / Target Category Application 

Ratea

Amount 

Handled / 

Area 

Treatedb

Dermal Unit 

Exposures 

(ug/lb ai)

Mitigationc

Inhalation 

Unit 

Exposures 

(ug/lb ai)

Mitigationc

Dermal Dose 

(mg/kg/day)d

Dermal 

MOEe

Inhalation 

Dose 

(mg/kgday)f

Inhalation 

MOEg

Combined 

MOEh

Mixer/Loader

DF/WDG 

Aerial 

application

Non-agricultural sites 0.281 lb 

ai//A 350 A

227

SL/No G 8.96

No-R

0.279 99

0.011 2,500

95

51.6

SL/G 0.0634 430 370

DF/WDG 

Commercial 

Treatment of 

Dry bulk 

Fertilizer Forestry -- Fertilizer, dry 

bulk, impregnated

1.99 lb 

ai/ton 960 tons 9.8EC

0.24

EC 0.234 120 0.00573 4,800 120

DF/WDG 

On Farm 

Treatment of 

Dry Bulk 

Fertilizer

0.199 lb 

ai//A 160 A 227SL/No G

8.96

No-R

0.0904 300 0.00356 7,700 290

DF/WDG 

Aerial 

ULV/Wide-area 

application

Forestry 0.199 lb 

ai//A 1200 A

227

SL/No G 8.96

No-R

0.678 41

0.0268 1000

39

51.6

SL/G 0.154 180 150

DF/WDG 

Groundboom 

application

Non-agricultural sites 0.281 lb 

ai//A 80 A 227SL/No G

8.96

No-R

0.0638 430 0.00251 11,000 410

Applicator

Aerial 

application Non-agricultural sites 0.281 lb ai//A 350 A

2.08

EC

0.0049

EC

0.00256 11000 0.00000603 4,600,000 11,000

Aerial 

ULV/Wide-area 

application

Forestry 0.199 lb 

ai//A 7500 A 0.0388 710 0.0000914 300,000 710

Groundboom 

application Non-agricultural sites 0.281 lb ai//A 80 A 78.6SL/No G

0.34

No-R

0.0221 1,200 0.0000955 290,000 1,200

Mechanicallypressurized 

Handgun 

application

Rights-of-way (e.g., 

utilities, railroad, 

roadways)

0.00281 lb 

ai/gal 1000 gal 1300SL/No G

3.9

No-R

0.0456 600 0.000138 200,000 600

Flagger

Aerial 

application Non-agricultural sites 0.281 lb ai//A 350 A

11

SL/No G

0.35

No-R

0.0135 2,000 0.00043 64,000 1,900
Sulfometuron methyl Draft Human Health Risk Assessment D427028

Page 16 of 32

Table 9.1.1. Summary of Occupational Handler Exposure and Risk Estimates for Sulfometuron Methyl.

Scenario Crop / Target Category Application 

Ratea

Amount 

Handled / 

Area 

Treatedb

Dermal Unit 

Exposures 

(ug/lb ai)

Mitigationc

Inhalation 

Unit 

Exposures 

(ug/lb ai)

Mitigationc

Dermal Dose 

(mg/kg/day)d

Dermal 

MOEe

Inhalation 

Dose 

(mg/kgday)f

Inhalation 

MOEg

Combined 

MOEh

Mixer/Loader/Applicator

DF/WDG 

Backpack

Rights-of-way (e.g., 

utilities, railroad, 

roadways)

0.00281 lb 

ai/gal

40 gal

8260 SL/No 

G

2.58

No-R

0.0116 2,400 0.00000363 7,600,000 2,400

Forestry

0.053 lb 

ai/gal 0.219 130 0.0000684 400,000 130

Landscaping, turf (lawns, 

athletic fields, parks, etc.)

Aquatic areas (lakes, 

ponds, etc.)

Industrial/commercial 

(tires, rail yards, junk 

yards, etc.)

0.00281 lb 

ai/gal

2510 SL/No 

G

30

No-R

0.00353 7,800 0.0000421 650,000 7,700

DF/WDG 

Manuallypressurized 

Handwand

Landscaping, turf (lawns, 

athletic fields, parks, etc.) 

Aquatic areas (lakes, 

ponds, etc.)

0.053 lb 

ai/gal

40 gal

100,000 

SL/No G

30

No-R

2.65 10

0.000795 35,000

10

430

SL/G 0.0114 2,400 2,200

Industrial/commercial 

(tires, rail yards, junk 

yards, etc.)

0.00281 lb 

ai/gal

100,000 

SL/No G

0.14 200 0.0000421 650,000 200

DF/WDG 

Mechanicallypressurized 

Handgun

Landscaping, turf (lawns, 

athletic fields, parks, etc.)

0.211 lb 

ai//A 5 A 1960 SL/No G

42

No-R

0.0259 1,100 0.000554 50,000 1,100

Industrial/commercial 

(tires, rail yards, junk 

yards, etc.) 0.00281 lb 

ai/gal

1000 gal

1300 SL/No 

G

3.9

No-R

0.0456 600 0.000138 200,000 600

Non-agricultural sites

Aquatic areas (lakes, 

ponds, etc.)

0.053 lb 

ai/gal

1300 SL/No 

G

0.861 SL/No 

G

32 0.00259 NoR

11,000 32

390 SL/G 0.259 110 110

Bolded MOEs are < HED’s LOC
Page 17 of 32

a. Based on maximum single application rates on registered labels (Appendix C).

b. Based on the Science Advisory Council for Exposure Policy 9.1: Standard Values for Daily Acres Treated in 

Agriculture. 

c. Based on the “Occupational Pesticide Handler Unit Exposure Surrogate Reference Table” (March, 2013). Mitigation 

Level: SL/No G = single layer clothing/no gloves; SL/G = single layer of clothing/gloves; No-R = no respirator; EC = 

engineering controls (e.g., enclosed cockpit for aerial applicators).

d. Dermal Dose (mg/kg/day) = [Rate (lb ai/A or lb ai/gal) * UE (mg/lb ai) * Acres Treated or Amount handled (A or 

gal/day)] * Dermal Absorption (100%) /BW (80 kg).

e. Dermal MOE = POD (27.5 mg/kg/day)/ Dermal Dose (mg/kg/day). LOC = 100.

f. Inhalation Dose (mg/kg/day) = [Rate (lb ai/A or lb ai/gal) * UE (mg /lb ai) * Acres Treated or Amount handled (A or 

gal/day)] /BW (80 kg).

g. Inhalation MOE = POD (27.5 mg/kg/day)/ Inhalation Dose (mg/kg/day). LOC = 100.

h. Combined MOE = POD (27.5 mg/kg/day) / Combined dose (dermal + inhalation).

9.2 Occupational Post-application Exposure/Risk Estimates

Occupational exposures to workers re-entering sulfometuron methyl-treated non-agricultural use 

sites are not anticipated because contact with previously treated areas is unlikely; therefore, a 

quantitative post-application assessment was not conducted for those sites. However, for the 

forestry/Christmas tree uses, a quantitative occupational post-application assessment was 

conducted. Based on the use directions on product labels, exposure is expected to be minimal for 

most of the activities listed below since applications are to be made during the dormant stage of 

growth, and labels indicate that sprays that come in contact with the foliage may cause injury to 

the trees. However, risk estimates for these activities have been included here as a worst case 

scenario, and should be considered conservative.

The results of the dermal post-application exposure and risk assessment indicate that dermal 

MOEs ≥ LOC (MOEs ≥ 100) on day 0 for all scenarios, and, therefore, are not of concern to 

HED. 

Table 9.2.1. Summary of Occupational Post-application Dermal Exposure and Risk Estimates.

Crop Crop Height / 

Foliage Density Activity Transfer Coefficient (cm2/hr)

Residue1,2

(ug/cm2)

Dermal Dose3

(mg/kg-day)

MOE4

DAT (Day After Treatment) = 0 (12 hours)

Forestry

High

Full

Harvesting, Seedling 

Production 6,700 0.022 0.015 1,800

High

Full

Irrigation (hand set) 1,900

0.56

0.106 260

High

Full

Harvesting, Seed Cone 

(Conifers) 1,400 0.078 350

High

Full / Min Scouting 580 0.078 850

Low

Min

Transplanting 230 0.032 2,100

High /Low

Full/Min

Hand weeding 100 0.013 4,900

Christmas 

tree 

plantations

High/Low

Full/Min

Hand weeding, 

Grading/Tagging 100

0.14

0.001 20,000

Low

Min

Transplanting 230 0.003 8,700

High/Low

Full/Min

Scouting / Shaping 580 0.008 3,400

High

Full

Hand harvesting 1,400 0.019 1,400
Sulfometuron methyl Draft Human Health Risk Assessment D427028

Page 18 of 32

Table 9.2.1. Summary of Occupational Post-application Dermal Exposure and Risk Estimates.

Crop Crop Height / 

Foliage Density Activity Transfer Coefficient (cm2/hr)

Residue1,2

(ug/cm2)

Dermal Dose3

(mg/kg-day) MOE4

DAT (Day After Treatment) = 0 (12 hours)

High/Low

Full Irrigation (hand set) 1,900 0.026 1,100

1. TTR for seedling production/harvesting = Application Rate × F × (1-D)t × 4.54E8 μg/lb × 2.47E-8 acre/cm2; where F = 0.1 and D = 0.10 

per day.

2. DFR for all other activities = Application Rate × F × (1-D)t × 4.54E8 μg/lb × 2.47E-8 acre/cm2; where F = 0.25 and D = 0.10 per day 

3. Daily Dermal Dose = [DFR (μg/cm2) × Transfer Coefficient × 0.001 mg/μg × 8 hrs/day × dermal absorption (100 %)]  BW (80 kg).

4. MOE = POD (27.5 mg/kg/day) / Daily Dermal Dose. 

Sulfometuron methyl is classified as Toxicity Category III via the dermal route and for eye 

irritation potential, and Toxicity Category IV for dermal irritation potential. It is not a skin 

sensitizer. Under 40 CFR 156.208 (c) (2) (iii), ai’s classified as Toxicity Category III or IV for 

acute dermal, eye irritation and primary skin irritation are assigned a 12-hour Restricted Entry 

Intervals (REI). Therefore, the [156 subpart K] Worker Protection Statement REI of 12 hours is 

adequate to protect workers from post-application exposures to sulfometuron methyl. The 

occupational post-application assessment indicated no risks of concern on the day of application 

as well; therefore, HED recommends a 12-hour REI for the sulfometuron methyl labels. 

It is noted that several labels require either a 4-hour or a 48-hour REI. For some of the 

sulfometuron methyl labels, multiple active ingredients are included in the end-use product and 

these additional active ingredients may require a longer REI. REIs may be reduced from 12-

hours if certain criteria are met in accordance with the Pesticide Registration (PR) Notice 95-3 

[Reduction of WPS Interim REIs for Certain Low Risk Pesticides]7. In PR Notice 95-3, there are 

a set of criteria listed for the active ingredient that must be met for chemicals to be eligible for a 

reduced REI. These criteria include:

1. The active ingredient is in Toxicity category III or IV based upon data for acute dermal 

toxicity, acute inhalation toxicity, primary skin irritation, and primary eye irritation. 

Acute oral toxicity data were used if no acute dermal data were available. If EPA lacked 

data on primary skin irritation, acute inhalation, or primary eye irritation of the active 

ingredient, the Agency reviewed data on that end-point for similar active ingredients 

(analogs), and excluded such active ingredients from consideration for the reduced REI, 

if the analog is in Toxicity Category I or II for that endpoint.

2. The active ingredient is not a dermal sensitizer (or in the case of biochemical and 

microbial active ingredients, no known reports of hypersensitivity exist).

3. The active ingredient is not a cholinesterase inhibitor (NMethyl carbamate and 

Organophosphate) as these chemicals are known to cause large numbers of pesticide 

poisonings and have the potential for serious neurological effects.

4. No known reproductive, developmental, carcinogenic, or neurotoxic effects have been 

associated with the active ingredient. If active ingredients did not have data available for 

these chronic health effects, EPA considered data on appropriate chemical and biological 

analogs. Active ingredients that have been classified as carcinogenic in Category B 

(probable human carcinogen) or Category C with a potency factor, Q* (possible human 

carcinogen, for which quantification of potential risk is considered appropriate), or are 

scheduled for the Health Effects Division's Cancer Peer Review process, were omitted 

from consideration.

 

7 Available: http://www.epa.gov/PR_Notices/pr95-3.html
Sulfometuron methyl Draft Human Health Risk Assessment D427028

Page 19 of 32

5. EPA does not possess incident information (illness or injury reports) that are ``definitely'' 

or ``probably'' related to post-application exposures to the active ingredient.

Upon review of the criteria for the active ingredient only, it appears that sulfometuron methyl

consistent with the criteria in PRN 95-3 that allow for a 4-hour REI. Note: The PR Notice also 

includes similar criteria for the end-use product. These criteria have not been evaluated by 

HED. Based solely on the active ingredient criteria, HED would recommend for reduction of the 

REI for sulfometuron methyl.
Sulfometuron methyl Draft Human Health Risk Assessment D427028

Page 20 of 32

Appendix A: Chemical Identity Tables.

Table A.1. Chemical Identity of Sulfometuron Methyl.

Chemical Structure

Empirical Formula C15H16N4O5S

Common Name Sulfometuron Methyl

IUPAC name methyl 2-(4,6-dimethylpyrimidin-2-ylcarbamoylsulfamoyl)benzoate

CAS Name methyl 2-[[[[(4,6-dimethyl-2-

pyrimidinyl)amino]carbonyl]amino]sulfonyl]benzoate

CAS Registry Number 74222-97-2

Chemical Class Pyrimidinylsulfonylurea Herbicides

Table A.2. Physiochemical Properties of Sulfometuron Methyl.

Parameter Value Reference

Molecular Weight 364.4

The Pesticide Manual: A World 

Compendium, 9th ed., 1991, C.R. 

Worthington, ed. The British Crop 

Protection Council, Surrey, UK pg. 774

Melting point 203-205°C

Physical state Colorless Solid

Vapor pressure (25°C) 6.0 x 10-5 mm Hg

Water solubility (25°C) 70 ppm

Log Kow (25°C) 1.2
Sulfometuron methyl Draft Human Health Risk Assessment D427028

Page 21 of 32

Appendix B: Sulfometuron Methyl Acute, Subchronic, and Chronic Toxicity Profile.

Table B.1. Sulfometuron Methyl Data Requirements.

Test Technical

Required Satisfied

870.1100 Acute Oral Toxicity ......................................................

870.1200 Acute Dermal Toxicity .................................................

870.1300 Acute Inhalation Toxicity .............................................

870.2400 Primary Eye Irritation ...................................................

870.2500 Primary Dermal Irritation .............................................

870.2600 Dermal Sensitization.....................................................

yes

yes

yes

yes

yes

yes

yes

yes

yes

yes

yes

yes

870.3100 Oral Subchronic (rodent)..............................................

870.3150 Oral Subchronic (nonrodent) ........................................

870.3200 21/28-Day Dermal ........................................................

870.3250 90-Day Dermal .............................................................

870.3465 90-Day Inhalation .........................................................

no

no

yes

no

no1

--

--

yes

--

--

870.3700 Developmental Toxicity (rodent)..................................

870.3700 Developmental Toxicity (nonrodent)............................

870.3800 Reproduction ................................................................

yes

yes

no2

yes

yes

--

870.4100a Chronic Toxicity (rodent).............................................

870.4100b Chronic Toxicity (nonrodent).......................................

870.4200a Carcinogenicity (rat).....................................................

870.4200b Carcinogenicity (mouse)...............................................

870.4300 Chronic Toxicity/Carcinogenicity (rodent)...................

no2

yes

no2

no2

no2

--

yes

--

--

--

870.5100 Mutagenicity—Gene Mutation - bacterial....................

870.5300 Mutagenicity—Gene Mutation - mammalian...............

870.5375 Mutagenicity—Structural Chromosomal Aberrations..

870.5385 Mutagenicity—Structural Chromosomal Aberrations..

870.5395 Mutagenicity—Other Genotoxic Effects......................

870.5550 Mutagenicity—Other Genotoxic Effects......................

yes

yes

yes

yes

yes

yes

yes

yes

yes

yes

yes

yes

870.6100 Acute Delayed Neurotox. (hen)....................................

870.6100 90-Day Neurotoxicity (hen)..........................................

870.6200a Acute Neurotox. Screening Battery (rat) ......................

870.6200b 90-Day Neurotoxicity Screening Battery (rat)..............

870.6300 Developmental Neurotoxicity.......................................

no

no

no1

no1

no

--

--

--

--

--

870.7485 General Metabolism .....................................................

870.7600 Dermal Penetration .......................................................

870.7800 Immunotoxicity ............................................................

yes

no

no1

yes

--

--

1 HASPOC concluded the subchronic inhalation, neurotoxicity (acute and subchronic), and immunotoxicity studies 

are not required at this time (K. Rury; 02-AUG-2012; TXR#0056431 and K. Rury; 06-AUG-2013; TXR#0056723).

2 Given the limited use pattern and low likelihood for chronic durations of exposure for this compound, rodent 

chronic toxicity or carcinogenicity studies were not required. 
Sulfometuron methyl Draft Human Health Risk Assessment D427028

Page 22 of 32

Table B.2. Acute Toxicity Profile – Sulfometuron Methyl.

Guideline No. Study Type MRID 

No.(s) Results Toxicity Category

870.1100 Acute oral rat 43089201 LD50 >5g/kg IV

870.1200 Acute dermal rabbit 43089202 LD50 >2g/kg III

870.1300 Acute inhalation rat 43089203 LC50 >5.0 mg/L IV

870.2400 Acute eye irritation rabbit 00071412 Minimal irritant III

870.2500 Acute dermal irritation rabbit 41672808 Not a dermal 

irritant2

IV

870.2600 Skin sensitization rabbit 43089204 Not a dermal 

sensitizer N/A

1 All studies were conducted on technical grade Sulfometuron methyl, of at least 98.8%, purity.

2 Minimal skin irritation was noted in the acute dermal toxicity study (MRID No. 43089202) and an older dermal 

irritation study of a 75% formulation (MRID No. 00071411).

Table B.3. Subchronic, Chronic and Other Toxicity Profile – Sulfometuron Methyl

Guideline 

No. Study Type MRID No. (year)/ Classification/Doses Results

870.3200 21-Day dermal 

toxicity (rabbit)

00126714 (1983) 

Acceptable/non-guideline 

M/F: 0, 125, 500, 2000 

mg/kg/day

NOAEL = 2000 mg/kg/day.

LOAEL not observed.

870.3700a Prenatal 

developmental 

(rabbit)

Main study

00078798 (1981) 

Acceptable/non-guideline 

F: 0, 30, 100, 300 

mg/kg/day

Range-finding

00078797 (1981)

F: 100, 300, 750, 1000 

mg/kg/day

Maternal NOAEL =300 mg/kg/day (HDT).

Maternal LOAEL = 750 mg/kg/day based on 

abortion observed in the range-finding study.

Developmental NOAEL = 300 mg/kg/day.

Developmental LOAEL not observed.

870.3700b Prenatal 

developmental in 

(rat)

00078796 (1981) 

Unacceptable/guideline 

Run I F: 0, 5,000, 20,000, 

40,000 and 60,000 ppm 

Run II & III F: 0, 50, 

1000, and 5,000 ppm (433 

mg/kg/day) 

Maternal NOAEL = >433 mg/kg/day.

Maternal LOAEL not observed.

Developmental NOAEL = >433 mg/kg/day.

Developmental LOAEL not observed. 

870.4100b Chronic toxicity 

(dog)

00129051 (1983) 

Acceptable/guideline 

M: 0, 5.2, 27.5, 152.6 

mg/kg/day 

F: 0, 5.3, 28.3, and 148.5 

mg/kg/day 

NOAEL = 27.5 mg/kg/day.

LOAEL = 148.5 mg/kg/day, based on hemolytic 

anemia in both sexes, decreased body-weight 

gain in males, and increased alkaline 

phosphatase in males and females. Effects on 

body weight were observed beginning on the 

fourth week of exposure (and persisting 

throughout the study).

Gene 

Mutation

Salmonella/ 

Microsome assay

00078792 (1979) 

Acceptable/guideline in 

strains TA 1535, TA 

1537, TA 98 and TA 100 

in the presence or absence 

of activation.

No mutagenic activity for all strains of bacteria 

tested.
Sulfometuron methyl Draft Human Health Risk Assessment D427028

Page 23 of 32

Table B.3. Subchronic, Chronic and Other Toxicity Profile – Sulfometuron Methyl

Guideline 

No. Study Type MRID No. (year)/ Classification/Doses Results

Gene 

mutation 

Chinese Hamster 

Ovary

00078793 (1981)

Acceptable/guideline

CHO cell line was used to 

detect mutations for 

HGPRT

No mutagenic activity with or without 

activation.

Chromosome 

aberration

Chinese Hamster 

Ovary in vitro 

cytogenetic assay

00146846 (1981)

Acceptable/guideline

CHO in vitro assay with 

and without activation

No increase in chromosome damage and 

aberrations.

Unscheduled 

DNA 

synthesis

Unscheduled DNA 

synthesis in rat 

hepatocytes in vitro

00146847 (1983)

Acceptable/guideline No induction of UDS was observed.
Sulfometuron methyl Draft Human Health Risk Assessment D427028

Page 24 of 32

Appendix C: Registered Sulfometuron Methyl Use Patterns

The use information provided in the following table is mostly based on the Biological and 

Economic Analysis Division’s (BEAD) Master Label Report (dated 5/29/2012). One additional 

product has been registered since this report, was reviewed for this assessment, and was not 

found to include any additional use sites and/or higher application rates than those included 

below.

Use Site Applic. Timing, Type, and Equip. Formulation 

Max 

Application 

Rate

Restricted Entry 

Interval (REI)

Agricultural Fallow 

/ Idleland / 

Conservation 

Reserve

When needed 

Broadcast

Groundboom and Helicopter

Water 

Dispersible 

Granular 

(WDG)

0.281 lb ai/A 4 hr

Agricultural RightsOf-Way / 

Fencerows / 

Hedgerows

When needed

Broadcast / Spot

Aerial (aircraft and helicopter), 

Groundboom and Handheld

WDG

0.281 lb ai/A

0.00281 lb 

ai/gal

4 hr

Agricultural 

Uncultivated Areas

When needed

Broadcast / Spot

Aerial (aircraft and helicopter), 

Groundboom and Handheld

WDG

0.281 lb ai/A

0.053 lb 

ai/gal

4 hr

Agricultural / Farm 

Premises

When needed

Broadcast

Groundboom

WDG 0.250 lb ai/A NA

Airports/Landing 

Fields

When needed

Broadcast / Spot

Aerial (aircraft and helicopter), 

Groundboom and Handheld

WDG

0.281 lb ai/A

0.053 lb 

ai/gal

NA

Forestry

Multiple depending on tree type (pretransplant, post-transplant, pre-emergence, 

post-emergence, preplant, etc)

Broadcast

Impregnated Fertilizer

Aerial (aircraft and helicopter), 

Groundboom

WDG

0.199 lb ai/A

0.053 lb 

ai/gal

4 - 48 hr

depending on label

Christmas Tree 

Plantations

Preemergence, early postemergence, 

dormant

Broadcast

Groundboom, Helicopter

WDG 0.049 lb ai/A 48 hr

Commercial / 

Industrial Lawns

Broadcast

Aerial (aircraft and helicopter), 

Groundboom

WDG 0.281 lb ai/A NA

Drainage systems

When needed

Broadcast WDG

0.281 lb ai/A

0.053 lb 

ai/gal

NA
Sulfometuron methyl Draft Human Health Risk Assessment D427028

Page 25 of 32

Use Site Applic. Timing, Type, and Equip. Formulation 

Max 

Application 

Rate

Restricted Entry 

Interval (REI)

Aerial (helicopter), Groundboom and 

Handheld

Industrial / 

Construction Areas

When needed

Broadcast

Aerial (aircraft and helicopter), 

Groundboom, Handheld

WDG

0.281 lb ai/A

0.00281 lb 

ai/gal

NA

Intermittently 

Flooded Areas

When needed

Broadcast

Aerial (aircraft and helicopter), 

Groundboom, Handheld

WDG

0.281 lb ai/A

0.00281 lb 

ai/gal

NA

Nonagricultural 

Rights-Of-Way / 

Fencerows / 

Hedgerows

When needed

Broadcast

Aerial (aircraft and helicopter), 

Groundboom, Handheld

WDG

0.281 lb ai/A

0.00281 lb 

ai/gal

NA

Nonagricultural 

Uncultivated 

Areas/Soils

When needed

Broadcast

Aerial (aircraft and helicopter), 

Groundboom, Handheld

WDG

0.281 lb ai/A

0.00281 lb 

ai/gal

NA

Ornamental Lawns 

and Turf

When needed

Broadcast / Spot

Aerial (aircraft and helicopter), 

Groundboom, and Handheld

WDG

0.281 lb ai/A

0.053 lb 

ai/gal

NA

Paved Areas 

(Private 

Roads/Sidewalks)

Preconstruction

Groundboom

WDG 0.25 lb ai/A NA

Rangeland

Fall / Spring

Broadcast

Aerial (aircraft) and Groundboom

WDG 0.07 lb ai/A 4 hr

Refuse/Solid Waste 

Sites (Outdoor)

When needed

Broadcast / Spot

Aerial (helicopter), Groundboom, 

Handheld

WDG

0.281 lb ai/A

0.00281 lb 

ai/gal

NA

Sewage Disposal 

Areas

When needed

Broadcast / Spot

Aerial (aircraft and helicopter), 

Groundboom, Handheld

WDG

0.281 lb ai/A

0.00281 lb 

ai/gal

NA

Swamps / Marshes / 

Wetlands / Stagnant 

Water

When needed

Broadcast / Spot

Aerial (aircraft and helicopter), 

Groundboom, and Handheld

WDG

0.281 lb ai/A

0.053 lb 

ai/gal

NA

Utility Poles / 

Rights-of-Way

When needed

Broadcast / Spot WDG

0.281 lb ai/A

0.00281 lb 

ai/gal

NA
Sulfometuron methyl Draft Human Health Risk Assessment D427028

Page 26 of 32

Use Site Applic. Timing, Type, and Equip. Formulation 

Max 

Application 

Rate

Restricted Entry 

Interval (REI)

Aerial (aircraft and helicopter), 

Groundboom, and Handheld
Sulfometuron methyl Draft Human Health Risk Assessment D427028

Page 27 of 32

Appendix D: Dietary Exposure/Risk Modeling Input and Output

Filename: C:\Users\slevy\Desktop\Sulfometuron-methyl\Sulfo.r08

Chemical: Sulfometuron

RfD(Chronic): .275 mg/kg bw/day NOEL(Chronic): 0 mg/kg bw/day

RfD(Acute): 0 mg/kg bw/day NOEL(Acute): 0 mg/kg bw/day

Date created/last modified: 04-08-2015/12:54:12 Program ver. 3.16, 03-08-d

Comment: No acute or cancer; no food uses - water only

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

 EPA Crop Def Res Adj.Factors Comment

 Code Grp Commodity Name (ppm) #1 #2 

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

8601000000 86A Water, direct, all sources 0.492000 1.000 1.000 

8602000000 86B Water, indirect, all sources 0.492000 1.000 1.000 

US EPA Ver. 3.16, 03-08-d

DEEM-FCID Chronic analysis for SULFOMETURON NHANES 2003-2008 2-day

Residue file name: C:\Users\slevy\Desktop\Sulfometuron\Sulfo.r08

 Adjustment factor #2 used.

Analysis Date 04-08-2015/12:55:03 Residue file dated: 04-08-2015/12:54:12

Reference dose (RfD, Chronic) = .275 mg/kg bw/day

COMMENT 1: No acute or cancer; no food uses - water only

===============================================================================

 Total exposure by population subgroup

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

 Total Exposure

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

 Population mg/kg Percent of 

 Subgroup body wt/day Rfd 

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

Total US Population 0.010302 3.7%

Hispanic 0.009836 3.6%

Non-Hisp-White 0.010596 3.9%

Non-Hisp-Black 0.008501 3.1%

Non-Hisp-Other 0.011874 4.3%

Nursing Infants 0.009320 3.4%

Non-Nursing Infants 0.034265 12.5%

Female 13+ PREG 0.009700 3.5%

Children 1-6 0.013195 4.8%

Children 7-12 0.008589 3.1%

Male 13-19 0.007082 2.6%

Female 13-19/NP 0.007936 2.9%

Male 20+ 0.009598 3.5%

Female 20+/NP 0.010821 3.9%

Seniors 55+ 0.009961 3.6%

All Infants 0.026564 9.7%

Female 13-50 0.010252 3.7%

Children 1-2 0.014861 5.4%

Children 3-5 0.012521 4.6%

Children 6-12 0.009030 3.3%

Youth 13-19 0.007513 2.7%

Adults 20-49 0.010278 3.7%

Adults 50-99 0.010161 3.7%

Female 13-49 0.010241 3.7%
Sulfometuron methyl Draft Human Health Risk Assessment D427028

Page 28 of 32

Appendix E. Review of Human Research

This risk assessment relies in part on data from studies in which adult human subjects were 

intentionally exposed to a pesticide or other chemical. These data are subject to ethics review 

pursuant to 40 CFR 26, have received that review, and are compliant with applicable ethics 

requirements. For certain studies, that review may have included review by the Human Studies 

Review Board. Descriptions of data sources as well as guidance on their use can be found at:

http://www.epa.gov/pesticides/science/handler-exposure-data.html and 

http://www.epa.gov/pesticides/science/post-app-exposure-data.html.
Sulfometuron methyl Draft Human Health Risk Assessment D427028

Page 29 of 32

Appendix F. Occupational Non-cancer Algorithms

Potential daily exposures for occupational handlers are calculated using the following formulas:

E=UE * AR * A * 0.001 mg/ug

where:

E = exposure (mg ai/day),

UE = unit exposure (μg ai/lb ai),

AR = maximum application rate according to registered labels (lb ai/A), and

A = area treated or amount handled (e.g., A/day).

The daily doses are calculated using the following formula:

ADD= 

E * AF

BW

where:

ADD = average daily dose absorbed in a given scenario (mg ai/kg/day),

E = exposure (mg ai/day),

AF = absorption factor (inhalation), and

BW = body weight (kg).

MOE: Non-cancer risk estimates for each application handler scenario are calculated using a 

MOE, which is a ratio of the toxicological endpoint to the daily dose of concern. The daily 

inhalation dose received by occupational handlers is compared to the appropriate POD (i.e., 

NOAEL) to assess the risk to occupational handlers. All MOE values are calculated using the 

following formula:

MOE= 

POD

ADD

where:

MOE = margin of exposure: value used by HED to represent risk estimates (unitless),

POD = point of departure (mg/kg/day), and

ADD = average daily dose absorbed in a given scenario (mg ai/kg/day).

Potential daily exposures for occupational post-application workers are calculated using the 

following formulas:

DFRt=AR * F* (1-D)t* (4.54E8

ug

lb) * (2.47E-8

A

cm2

)

where:
Sulfometuron methyl Draft Human Health Risk Assessment D427028

Page 30 of 32

DFRt = dislodgeable foliage residue on day "t" (μg/cm2),

AR = application rate (lb ai/acre),

F = fraction of ai retained on foliage or 25% (unitless),

D = fraction of residue that dissipates daily or 10% (unitless), and

t = number of days after application day (days).

E=TC * DFR t* ET * 0.001

mg

ug

where:

E = exposure (mg ai/day),

TC = transfer coefficient (cm2/hr),

DFRt = dislodgeable foliar residue on day “t” (μg/cm2), and

ET = exposure time (hours/day).

The daily doses are calculated using the following formula:

ADD= 

E * AF

BW

where:

ADD = average daily dose absorbed in a given scenario (mg ai/kg/day),

E = exposure (mg ai/day),

AF = absorption factor (dermal and/or inhalation), and

BW = body weight (kg).

Margin of Exposure: Non-cancer risk estimates for each scenario are calculated using a Margin 

of Exposure (MOE), which is a ratio of the toxicological endpoint to the daily dose of concern. 

The daily dermal dose received by occupational post-application workers is compared to the 

appropriate POD (i.e., NOAEL) to assess the risk to occupational post-application workers. All 

MOE values are calculated using the following formula:

MOE= 

POD

ADD

where:

MOE = margin of exposure: value used by HED to represent risk estimates (unitless),

POD = point of departure (mg/kg/day), and

ADD = average daily dose absorbed in a given scenario (mg ai/kg/day).
Sulfometuron methyl Draft Human Health Risk Assessment D427028

Page 31 of 32

Appendix G. Spray Drift Detailed Description

Off-target movement of pesticides can occur via many types of pathways and it is governed by a 

variety of factors. Sprays that are released and do not deposit in the application area end up offtarget and can lead to exposures to those the chemical may directly contact. Sprays can also 

deposit on surfaces where individuals come into contact with residues on these surfaces, leading 

to indirect exposures (e.g., children playing on lawns where residues have deposited next to 

treated fields).

The approach to be used for quantitatively incorporating spray drift into risk assessment is based 

on a premise of compliant applications which, by definition, should not result in direct exposures 

to individuals because of existing label language and other regulatory requirements intended to 

prevent them8. [Direct exposures would include inhalation of the spray plume or being sprayed 

directly.] Rather, the exposures addressed here are thought to occur indirectly through contact 

with impacted areas, such as residential lawns, when compliant applications are conducted. 

Given this premise, exposures for children (1 to 2 years old) and adults who have contact with 

turf where residues are assumed to have deposited via spray drift thus resulting in an indirect 

exposure are the focus of this analysis analogous to how exposures to turf products are 

considered in risk assessment. 

In order to evaluate the drift potential and associated risks, an approach based on drift modeling 

coupled with techniques used to evaluate residential uses of pesticides was utilized. Essentially, 

a residential turf assessment based on exposure to deposited residues has been completed to 

address drift from the agricultural applications of sulfometuron methyl. In the spray drift 

scenario, the deposited residue value was determined based on the amount of spray drift that may 

occur at varying distances from the edge of the treated field using the AgDrift® (v2.1.1) model 

and the Residential Exposure Assessment Standard Operating Procedures Addenda 1: 

Consideration of Spray Drift Policy. Once the deposited residue values were determined, the 

remainder of the spray drift assessment was based on the algorithms and input values specified in 

the 2012 Standard Operating Procedures for Residential Risk Assessment (SOPs). 

A screening approach was developed based on the use of the AgDrift® model in situations where 

specific label guidance that defines application parameters is not available9,10. AgDrift® is 

appropriate for use only when applications are made by aircraft, airblast orchard sprayers, and 

groundboom sprayers. When AgDrift® was developed, a series of screening values (i.e., the Tier 

1 option) were incorporated into the model and represent each equipment type and use under 

varied conditions. The screening options specifically recommended in this methodology were 

selected because they are plausible and represent a reasonable upper bound level of drift for 

common application methods in agriculture. These screening options are consistent with how 

spray drift is considered in a number of ecological risk assessments and in the process used to 

develop drinking water concentrations used for risk assessment. In all cases, each scenario is to 

be evaluated unless it is not plausible based on the anticipated use pattern (e.g., herbicides are 

not typically applied to tree canopies) or specific label prohibitions (e.g., aerial applications are 

not allowed). Section 6.1.1 provides the screening level drift related risk estimates. 

 

8 This approach is consistent with the requirements of the EPA’s Worker Protection Standard.

9 http://www.agdrift.com/

10 Note that for many cases the scenarios outlined in the screening approach represent actual use practice so risk 

assessors should be aware and characterize these appropriately.
Sulfometuron methyl Draft Human Health Risk Assessment D427028

Page 32 of 32

In many cases, risks are of concern when the screening level estimates for spray drift are used as 

the basis for the analysis. In order to account for this issue and to provide additional risk 

management options additional spray drift deposition fractions were also considered. These drift 

estimates represent plausible options for pesticide labels.