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AMENDMENT TO SEPTEMBER 18, 2008 SULFOMETURON METHYL 

REREGISTRATION ELIGIBILITY DECISION 

The Environmental Protection Agency (EPA, or the Agency) is publishing an amendment to the 

September 18, 2008 Sulfometuron Methyl Reregistration Eligibility Decision (SMM RED) 

document. 

Stakeholder comments, mitigation proposals, and other information received by the Agency 

following the publication of the SMM RED have provided reason for the Agency to further 

refine the ecological risk assessment for non-target plant species and the buffer zone 

requirements imposed in the SMM RED document to mitigate those risks. Based on these 

changes, the Agency was also able to revise the occupational handler exposure scenarios and 

revisit the Personal Protective Equipment (PPE) requirements of the SMM RED. All submitted 

comments, mitigation proposals, and other information connected to the Agency’s decision to 

revisit the RED mitigation measures can be found in the sulfometuron methyl docket (EPA-HQOPP-2008-0129) at www.regulations.gov. The Agency’s response to comments received on the 

SMM RED are also located in the docket. 

This document addresses public comments and mitigation proposals submitted to the Agency 

that effect the estimated risk and mitigation measures for sulfometuron methyl. This document 

also presents an updated label table for sulfometuron methyl that includes the amended 

mitigation as well as mitigation requirements required by the SMM RED that were not effected 

by public comments. 

Public comments that did not affect the risk assessment conclusions or mitigation decisions for 

sulfometuron methyl are addressed in separate documents: comments relating to human health 

are addressed in the document, Sulfometuron Methyl: Response to Public Comments for Phase 3 

Amendment of Sulfometuron Methyl: HED Chapter of the Registration Eligibility Decision 

(RED), (W.Britton, D346177). Comments regarding ecological fate or ecotoxicity are addressed 

in the document, Response to Environmental Fate and Effects Related Comments on 

Sulfometuron Reregistration Eligibility Document (M.Barrett, K.Sappington, D346169). 

Comments regarding policy or process are addressed in the document, Response to Comments 

Received Following the Publication of the Sulfometuron Methyl Reregistration Eligibility 

Document (R.Wasem, 11-20-09). These documents can be found in the sulfometuron methyl 

docket: (EPA-HQ-OPP-2008-0129) at www.regulations.gov. 

Various stakeholders from both the commercial forestry and the railroad industry commented on 

mitigation measures outlined in the SMM RED. Most commenters expressed concern about the 

measures (including application parameters and buffer zones), intended to mitigate potential 

ecological risk to non-target organisms (endangered and non-endangered plant species). 

Commenters noted that some of the measures required in the RED would make it difficult or 

dangerous to use sulfometuron methyl in a commercial forestry or railroad rights-of-way 

settings. During the comment period, EPA met with representatives from National Association 

of Forest Owners (NAFO) and National Council for Air and Stream Improvement (NCASI) to 

discuss elements of the Agency’s risk assessment including application methods (such as 
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equipment and practices) and application rates relevant to forestry uses.1 Following the 

comment period, the technical registrant, DuPont, also proposed reduced application rates and 

modified application requirements.2

 These documents can be found in the sulfometuron methyl 

docket: (EPA-HQ-OPP-2008-0129) at www.regulations.gov. 

Based upon proposed changes to the application parameters for both the commercial forestry use 

and other non-forestry uses (e.g. non-crop areas, rights-of-way), the Agency revised its 

ecological exposure risk estimates for non-target plant species, as well as certain occupational 

risk estimates. A brief discussion of changes and summary of the revised ecological and 

occupational risks are presented below. 

Application (Release) Height 

RED label language requirement: 

Aerial applications more than 10-feet above the canopy are prohibited.

Various stakeholders commented that a prohibition of aerial applications higher than 10 feet 

above the canopy is not appropriate for forestry settings. When modeling aerial applications, the 

Agency can model several release heights, but typically models a 10 foot release height. 

However, many commercial forestry operations are sited on land with varying terrain, also, in 

commercial forestry practices, there may be “leave” trees (stag stands that can drastically vary 

the canopy height. 

Given the terrain of commercial forestry stands, the Agency agrees that a fixed aerial application 

height is potentially unsafe and impractical. As a result, the Agency will change the aerial 

application height restriction to language that prescribes the lowest application height that is safe 

for the applicator and efficacious for the target spray area. The mandatory statement about spray 

height now contains a condition to allow for greater heights when necessary for applicator safety. 

Amendment: 

For commercial forestry applications, spray should be released at the lowest height consistent 

with pest control and flight safety. Do not spray from heights greater than 10 feet unless it is 

required for applicator safety. 

Application Equipment 

RED label language requirement: 

The Agency did not prohibit or specify certain formulations for sulfometuron use scenarios in the 

SMM RED. 

 

1

 NAFO and NCASI’s discussion on typical commercial forestry pesticide application parameters and settings can 

be found in the sulfometuron methyl docket under the letter entitled “4/13/09 - NAFO and NCASI Response to 

2.25.09 Meeting with EPA.” 

2

 DuPont’s proposal of mitigation options was communicated via email and can be found in the sulfometuron methyl 

docket under the title “7/24/09 – Email Correspondence between DuPont and US EPA Regarding Sulfometuron 

Methyl RED Mitigation.” 
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The technical registrant, DuPont, proposed to limit aerial application of sulfometuron methyl to 

rotary craft for all uses except for sulfometuron methyl impregnated fertilizer. NAFO, NCASI, 

and other commenters to the public docket indicated that this proposal was consistent with 

current forestry practices. The potential for drift is generally much higher for applications made 

via fixed wing aircraft than applications made by helicopter, and therefore, restriction to 

application by rotary aircraft represents some risk reduction. (While sulfometuron methyl can 

continue to be applied via fixed wing aircraft as an impregnated fertilizer, this formulation is 

expected to produce less drift than application of the liquid formulation and therefore, is 

expected to present less risk concern.) 

Amendment: 

Aerial applications of liquid formulations of sulfometuron methyl are restricted to rotary aircraft 

only. 

Application Rates 

RED label language requirement: 

Maximum single application rate is 0.375 lb ai/A for all uses. 

No comments were submitted that discussed typical application rates for the commercial forestry 

use of sulfometuron methyl. In its meeting with the Agency, NAFO and NCASI indicated that 

an acceptable maximum single application rate for commercial forestry use is 0.199 lb ai/A. The 

technical registrant, DuPont, proposed an application rate of 0.281 lb ai/A. Since the application 

practices associated with commercial forestry lead to greater drift than applications associated 

with the non-forestry uses of sulfometuron methyl, the Agency will adopt the lower single 

maximum application rate of 0.199 lb ai/A for commercial forestry uses (proposed by the 

NAFO). The Agency will reduce the application rate of sulfometuron methyl to 0.281 lb ai/A for 

all other sulfometuron methyl uses which currently exceed this value (i.e., non-crop areas, rightsof-way). 

Amendment: 

Maximum single application rate for forestry use (hardwoods, conifers) is 0.199 lb ai/A. 

Maximum single application rate for non-agricultural rights-of-way uses is 0.281 lb ai/A. 

Nozzle Size Requirements 

RED label language requirement: 

All applications must be made using medium or coarser droplet size spectrum according to 

American Society of Agricultural and Biological Engineers (ASABE) (S572) definition. 

The technical registrant proposed that sulfometuron methyl product labels be modified to require 

extremely coarse droplet size for all uses (>500 Volume Median Diameter (VMD)) according to 

ASABE (S572) guidelines). In its meeting with the Agency, the NAFO did not indicate that 

there was a specific typical droplet size spectrum for commercial forestry uses but indicated that 

typical droplet spectrum size was indeed greater than fine to medium (100 – 250 VMD), which 

the Agency assumed in its 2007 ecological risk assessment. Various commenters indicated that 
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typical droplet size spectrum used in commercial forestry was greater than fine to medium and 

can be as large as extremely coarse. Because larger droplets result in less off target movement of 

a product, the requirement to increase the droplet size reduces the Agency’s concern for 

sulfometuron methyl drift. Therefore, the Agency will modify the sulfometuron methyl label to 

require that all liquid applications be made using a droplet spectrum size of extremely coarse or 

greater. The Agency notes that dry impregnated fertilizer is not applied through spray tip 

nozzles and, therefore, is considered separately from requirements for liquid formulation 

applications. 

Amendment: 

All applications of liquid formulation sulfometuron methyl must be made using extremely coarse 

droplet size (>500 VMD) or larger, according to ASABE (S572) definition. 

Required Weather Conditions for Application 

RED label language requirement: 

Applications may not be made to powdery dry soil or light sandy soil when less than a 60% 

chance of rainfall is predicted to occur in the treatment area within 48 hours of application. 

The Agency received comments regarding the soil characterization “light sandy soil,” noting that 

this is not a soil texture class and therefore is not enforceable or helpful to applicators. However, 

the Agency believes that it is not feasible from either a technical or practical standpoint to 

precisely define soil types based on textural content or organic matter content. The Agency also 

believes that additional characterization can be added to the label language to better describe 

erodible soil which may lead to offsite pesticide movement. 

Amendment: 

Applications may not be made to soil that is subject to wind erosion when less than a 60% 

chance of rainfall is predicted to occur in the treatment area within 48 hours. Soils that are 

subject to wind erosion usually have a high silt and/or fine to very fine sand fractions. Soils with 

low organic matter also tend to be prone to wind erosion. 

Revised Estimated Ecological Risk and Buffer Zone Requirements 

The Agency’s ecological risk mitigation actions in the RED were based upon potential direct risk 

to aquatic or terrestrial non-target plants, and potential indirect risks to animals that depend upon 

plants for growth, survival and reproduction (via off target drift or surface water runoff). Based 

upon changes to application methods, rates, and droplet size requirements, EPA revised the 

sulfometuron methyl ecological exposure assessment. No new data or comments were submitted 

that modified the Agency’s ecological hazard profile for sulfometuron methyl and, therefore, the 

revised ecological risk assessment of sulfometuron methyl results from changes that reduced the 

estimated environmental concentrations and improved the overall risk picture. Overall, potential 

risk to non-target plants has been reduced due to comments and proposals submitted by 

stakeholders. 
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During the reregistration process, the Agency determined that suflometuron methyl uses resulted 

in risk quotients (RQs) that exceeded its level of concern (LOC), but also determined that 

sulfometuron methyl provides a benefit to users. Limited use information at the time of the RED 

indicated that sulfometuron methyl was among the top 10 chemicals used for: forestry, roadside, 

railroad, electric utilities, and pipeline and industrial usage (1990 data); and California data 

(2001 – 2006) indicated that sulfometuron methyl was among the top 10 chemicals for 

forestry/timberland use. Although no benefits data were submitted in response to the SMM 

RED, the volume and substance of comments indicating the need for SMM containing products 

reflects the value of sulfometuron methyl to the user community. 

RED label language requirement: 

For Ground Applications: 

Do not apply within 100 feet of aquatic vegetation (such as, but not limited to, lakes, reservoirs, 

rivers, streams, marshes, ponds, estuaries, and commercial fish ponds, or water used as an 

irrigation source) and crops. 

For Aerial Applications: 

Do not apply within 500 feet of aquatic vegetation (such as, but not limited to, lakes, reservoirs, 

rivers, streams, marshes, ponds, estuaries, and commercial fish ponds, or water used as an 

irrigation source) and crops. 

Through the RED, the Agency required buffer zones of 500 feet for aerial applications, and 100 

feet for ground applications. The Agency selected 500 foot buffer zones, even though 

unacceptable RQs were modeled 900 feet downwind from applications because the Agency 

believed requiring buffers zones greater than 500 feet would have greatly reduced the benefits of 

sulfometuron methyl. When considering options to mitigate the ecological risk, the Agency also 

considered the benefits of sulfometuron methyl, namely its efficacy at extremely low rates and, 

its low ecological toxicity profile to other non-target organisms. After considering these 

variables in the absence of other relevant use information, the Agency selected buffer zones of 

500 feet and 100 feet respectively for aerial and ground applications as part of its registration 

eligibility decision for sulfometuron methyl (see Tables 1 and 2 below). 

Table 1. Tier II AgdriftTM RQs for Aerial Applications from the RED 

Distance Down wind RQs 

 Non-Endangered 

Species 

Endangered Species 

0 10411 189293 

50 3567 64848 

100 2039 37071 

200 978 17778 

500 400 7273 

750 289 5253 

Input Parameters: Air Tractor (Fixed Wing Aircraft); Rate 0.375 lb ai/A; Wind Speed 10mph; Release Height 10ft; Droplet Size 

Fine to Medium (100-250 VMD) 
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Table 2. Tier I AgdriftTM RQs for Ground Applications from the RED 

Distance Down wind RQs 

 Non-Endang Endang 

0 21233 386061 

50 367 6667 

100 200 3636 

200 106 1919 

Input Parameters: Ground Boom; Rate 0.375 lb ai/A; Wind Speed 10mph; Release Height 4.17ft; Droplet Size Fine to Very 

Fine (<100-175 VMD) 

Public comments regarding typical use patterns for sulfometuron methyl in commercial forestry 

settings, and in rights-of-way settings, has allowed the Agency to revise application parameters 

that reflect actual use scenarios. Based on changes to the application parameters for these uses, 

the Agency has revised the estimated ecological exposure from sulfometuron methyl. Revised 

deposition values for commercial forestry and rights-of-way uses of sulfometuron methyl are 

presented below in Table 3. 

Table 3. Revised Tier I & II Estimated Amount of Sulfometuron Methyl Spray Drift 

AgDriftTM Tier II II I I 

Distance Down 

Wind (Feet) 

Lb ai/A 

[% of app. rate] 

Lb ai/A 

[% of app. rate] 

Lb ai/A 

[% of app. rate] 

Lb ai/A 

[% of app. rate] 

0 0.0327 

[16.44] 

0.0463 

[16.47]

0.2845 

[101.0] 

0.2831 

[101.0] 

30 0.0103 

[5.16] 

0.0146 

[5.19]

0.0050 

[1.79] 

0.0031 

[1.09] 

50 0.007 

[3.52] 

0.01 

[3.56]

0.0034 

[1.19] 

0.0021 

[0.74] 

75 0.0048 

[2.42] 

0.0069 

[2.47]

0.0025 

[0.87] 

0.0015 

[0.55 

100 0.0031 

[1.56] 

0.0045 

[1.60]

0.0020 

[0.70] 

0.0012 

[0.44] 

150 0.0018 

[0.90] 

0.0026 

[0.93]

0.0014 

[0.51] 

0.0009 

[0.33] 

200 0.0012 

[0.60] 

0.0018 

[0.63]

0.0011 

[0.40] 

0.0007 

[0.26] 

 

App rate 0.199 0.281 0.281 0.281 

Wind speed 

(mph) 

10 10 Unknown1 Unknown1

App. height 

(feet) 

10 10 4.17 1.67 

Median droplet 

size (um) 

519 519 3412 3412

Droplet size 

distribution 

category (ASAE) 

Very Coarse to 

Extremely Coarse 

Very Coarse to 

Extremely Coarse 

Fine to Medium 

coarse 

Fine to Medium 

coarse 

App. equipment WASP Helicopter WASP Helicopter Ground Ground 

1

: value not specified in AgDRIFTTM model documentation; likely reflects 10 mph 2

: for ground application scenarios, the AgdriftTM tier I model is restricted to using Fine to Medium coarse, and cannot 

model Very Coarse, which is required. 
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The Agency believes that the revised application requirements are in line with typical application 

practices of both the commercial forestry and rights-of-way uses of sulfometuron methyl. Based 

upon revised RQs to non-target plants, the Agency is modifying the buffer zones required to 

mitigate ecological risk from sulfometuron methyl use. 

When revising the buffer zone requirements for sulfometuron methyl, the Agency attempted to 

maintain a similar risk-benefit balance that it struck at the time of the RED by adopting revised 

buffer zones with associated RQs similar to those regulated upon at the time of the RED. 

Therefore, the revised buffer zone for aerial applications is 75 feet (rotary craft only), 50 feet for 

ground (broadcast) applications, and 30 feet for hand held spot treatment applications. The 

Agency believes spot treatment applications present less risk for off target movement than 

broadcast applications and therefore have the shortest buffer zone. Revised risk quotients for 

aerial, ground, and hand held applications are presented in Tables 4, 5, 6 and 7. 

Table 4. Revised Tier II AgdriftTM Risk Quotients For Aerial Application (Rotary Wing) at 0.199 lb ai/A 

for Commercial Forestry Applications 

Distance Down 

Wind (feet) 

Deposition Value RQs 

 Non-Endang Endang 

0 0.0327 1817 33,030 

30 0.0103 572 10,404 

50 0.007 389 7071 

75 0.0048 267 4848 

100 0.0031 172 3131 

150 0.0018 100 1818 

200 0.0012 67 1212 

Input Parameters: Wasp (Helicopter); Rate 0.200 lb ai/A; Wind 10mph; Height 10ft; Droplet Size Extremely Coarse (>450 

VMD) 

Table 5. Revised Tier II AgdriftTM Risk Quotients for Aerial Application (Rotary Wing) at 0.281 lb ai/A 

for Rights-of-Way Applications

Distance Down 

Wind (feet) 

Deposition Value RQs 

 Non-Endang Endang 

0 0.0463 2,572 46,768 

30 0.0146 811 14,747 

50 0.01 556 10,101 

75 0.0069 383 6,970 

100 0.0045 250 4,545 

150 0.0026 144 2,626 

200 0.0018 100 1,818 

Input Parameters: Wasp (Helicopter); Rate 0.281 lb ai/A; Wind 10mph; Height 10ft; Droplet Size Extremely Coarse (>450 

VMD) 
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Table 6. Revised Tier I AgdriftTM Risk Quotients for Ground Application at 0.281 lb ai/A 

Distance Down Wind 

(feet) 

Deposition Value RQs 

 Non-Endang Endang 

0 0.2845 15806 287347 

30 0.0050 278 5051 

50 0.0034 189 3434 

75 0.0025 139 2525 

100 0.0020 111 2020 

150 0.0014 78 1414 

200 0.0011 61 1111 

Input Parameters: Ground Boom; Rate 0.200 lb ai/A; Wind 10mph; Height 4.17ft; Droplet Size Fine to Medium Coarse4

(341VMD) 

Table 7. Revised Tier I AgdriftTM Risk Quotients for Hand Held Equipment at 0.281 lb ai/A 

Distance Down 

Down Wind (feet) 

Deposition Value RQs 

 Non-Endang Endang 

0 0.2831 1573 285,959 

30 0.0031 172 3131 

50 0.0021 117 2121 

75 0.0015 83 1515 

100 0.0012 67 1212 

Input Parameters: Ground Boom; Rate 0.281 lb ai/A; Wind 10mph; Height 1.67ft3; Droplet Size Fine to Medium Coarse4 (341 

VMD) 

The Agency notes that for the ground application scenarios, the AgDriftTM model is limited to 

using “fine to medium coarse” droplet sizes (i.e., the model cannot be parameterized to reflect an 

extremely coarse droplet size). Since the Agency is requiring that all applications, including 

ground applications, use extremely coarse or coarser nozzles, the RQ’s presented in Table 6 and 

7 likely overestimate risk. A summary of revised buffer zone requirements for liquid 

formulations of sulfometuron methyl is presented in Table 8. 

Table 8. Summary of Revised Buffer Zone Requirements for Sulfometuron Methyl (Liquid Formulation) 

App. Method Use Scenario Rate (lb ai/A) Buffer zone Comment 

Aerial (rotary craft) commercial forestry 

(desidous, conifer and 

christmas tree 

plantations) 

0.199 75 ft 

Aerial (rotary craft) non-crop, rights of way, 0.281 75 ft 

Ground equipment forestry 0.199 50 ft 

Ground equipment non-crop rights of way, 0.281 50 ft broadcast spray 

equipment 

Hand held equipment forestry spot treatment, 

non-crop spot treatment 

0.281 30 ft 

 

3

 While no comments or data were received regarding the release height of non-forestry uses of sulfometuron 

methyl, the Agency revised the release height for this scenario base upon its own research an inquiry into the rightsof-way use (such as non-crop area use by the railroad industry). 

4

 Limitations in the model required EPA to assume a droplet spectrum size of Fine to Medium for this scenario. 
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Amendment: 

For aerial applications to commercial forestry sites, do not apply within 75 feet of aquatic 

vegetation including, but not limited to, lakes, reservoirs, rivers, streams, marshes, ponds, 

estuaries, and commercial fish ponds, or water used as an irrigation source, or crops. 

For aerial applications to non-forestry sites, do not apply within 75 feet of aquatic vegetation 

including, but not limited to, lakes, reservoirs, rivers, streams, marshes, ponds, estuaries, and 

commercial fish ponds, or water used as an irrigation source, or crops. 

For broadcast ground applications, do not apply within 50 feet of aquatic vegetation including, 

but not limited to, lakes, reservoirs, rivers, streams, marshes, ponds, estuaries, and commercial 

fish ponds, or water used as an irrigation source, or crops. 

For hand held applications, do not apply within 30 feet of aquatic vegetation including but not 

limited to, lakes, reservoirs, rivers, streams, marshes, ponds, estuaries, and commercial fish 

ponds, or water used as an irrigation source, or crops. 

Revised Human Health Risk Assessment and Personal Protective Equipment (PPE) 

Requirements 

Based upon changes to application rates for commercial forestry and non-crop rights-of-way 

uses, EPA has revised the sulfometuron methyl occupational handler risk estimates. No new 

data or comments were submitted that modified the Agency’s human health hazard profile for 

sulfometuron methyl, therefore, the revised occupational handler risk assessment resulted from 

changes that reduced the handler exposure estimates and improved the overall risk picture. 

RED Label Requirement: 

All mixers, loaders, applicators and other handlers must wear: 

Long-sleeved shirt and long pants and shoes plus socks. 

Chemical-resistant gloves when mixing and loading to support aerial applications, and when 

using handheld nozzles or other handheld equipment, and chemical-resistant apron when mixing 

and loading to support aerial applications. 

Some materials that are chemical-resistant to this product are” (registrant inserts correct 

chemical-resistant material). If you want more options, follow the instructions for category 

[registrant inserts A,B,C,D,E,F,G,or H] “on an EPA chemical-resistance category selection chart. 

All liquid mixers, loaders, applicators, and other handlers must wear: 

Long-sleeved shirt and long pants, and Shoes plus socks. 

Chemical-resistant gloves when mixing, loading, and applying for low pressure hand wand. 

During the reregistration process, the Agency determined that all but two of the occupational 

handler exposure scenarios were not of concern, (i.e., had Margins of Exposure (MOEs) >100) 

when baseline PPE was assumed (baseline PPE is defined as long shirt, long pants, shoes and 

socks). Table 9, which is taken from the SSM RED, presents the two dermal occupational 

handler scenarios where MOEs of concern were identified at baseline PPE. To reduce the 

potential occupational risk, the Agency required additional PPE (gloves and an additional layer 
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of clothing) which increased the MOE’s (90 for water dispersible granules, and 12,000 for 

liquids). 

Table 9. Sulfometuron Methyl Selected Occupational Scenario MOEs of Combined Dermal and Inhalation Exposure From 

RED (Baseline PPE)a

No. Scenario Target App. Rateb 

(lb ai/acre) 

Area 

Treated 

(acres) 

Dermalc

MOEs 

Inhalationd

MOEs

Combinede

MOEs 

Mixer/Loaders 

1 

WDGs: Aerial 

Equipment (Fixed 

Wing and 

Helicopter) 

Forestry (Hardwoods, 

Conifers), Non-Crop Areas 

(Public, Private, Military 

Lands) 

0.38 1200 65 5600 64 

Mixer/Loader/Applicators 

4 

Liquids: Low 

Pressure 

Handwand 

Non-Crop Areas 0.38 1 51 170000 51 

a Baseline = Long pants, long-sleeved shirt, no gloves 

b Application rate based upon maximum labeled value. 

 c Dermal MOE = Dermal NOAEL (27.5 mg/kg/day)/ ( Dermal Daily Dose [Reference W.Britton, 345025]) 

 d Inhalation MOE = Inhalation NOAEL (27.5 mg/kg/day) / ( Inhalation Daily Dose [Reference W.Britton, 345025]) 

 e Combined MOE = 1/((1/Dermal MOE)+(1/Inhalation MOE)) 

Based on the rate reductions proposed by stakeholders, the Agency has revised the occupational 

handler exposure assessment for sulfometuron methyl for commercial forestry use, and for uses 

where the application rate exceeded 0.281 lb ai/A (i.e., non-crop areas, rights-of-way). Table 10 

presents revised occupational exposure estimates, based on reduced application rates, for these 

scenarios. The exposure scenario mixing/loading/applying of liquids for low pressure hand 

wand results in a combined MOE = 97 at baseline PPE. While this exposure scenario is of 

potential concern, the Agency notes that the MOE = 97 is conservative since dermal absorption 

is estimated at 100%, and in reality, dermal absorption is likely much lower. Based upon these 

revised risk estimates, the Agency will not require additional PPE beyond baseline PPE for 

mixers, loaders, applicators and other handlers of sulfometuron methyl products. (A full address 

of revised occupational exposure and risk estimates can be found in the document: Sulfometuron 

methyl: Amendment to the “HED Chapter of the Reregistration Eligibility Decision Documents 

(RED) (D346064)” which presents revised MOE’s for additional handler scenarios which were 

not of risk concern at the time of the SMM RED.) 
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Table 10. Revised Sulfometuron Methyl Selected Occupational Scenario MOEs of Combined Dermal and Inhalation 

Exposure (Baseline PPE)a

No. Scenario Target App. Rateb 

(lb ai/acre) 

Area 

Treated 

(acres) 

Dermalc

MOEs 

Inhalationd

MOEs

Combinede

MOEs 

Mixer/Loaders 

1 

WDGs: Aerial 

Equipment (Fixed 

Wing and 

Helicopter) 

Forestry (Hardwoods, 

Conifers), Non-Crop Areas 

(Public, Private, Military 

Lands), Turf Unimproved 

0.19 1200 120 10500 120 

Mixer/Loader/Applicators 

4 

Liquids: Low 

Pressure 

Handwand 

Non-Crop Areas 0.28 1 97 320000 97 

a Baseline = Long pants, long-sleeved shirt, no gloves 

b Application rate based upon maximum labeled value. 

 c Dermal MOE = Dermal NOAEL (27.5 mg/kg/day)/ ( Dermal Daily Dose [Reference W.Britton, 345025]) 

 d Inhalation MOE = Inhalation NOAEL (27.5 mg/kg/day) / ( Inhalation Daily Dose [Reference W.Britton, 345025]) 

 e Combined MOE = 1/((1/Dermal MOE)+(1/Inhalation MOE)) 

Amendment: 

All mixers, loaders, applicators and other handlers must wear: 

Long-sleeved shirt and long pants, and Shoes plus socks. 

A revised sulfometuron methyl label table is attached (Table 11) to this document along with the 

September 2008 RED. All other mitigation measures, label statements, and data requirements 

stated in the September 2008 SMM RED, not specifically discussed above, remain in effect. 

Supporting documents for the Amendment of the Sulfometuron methyl RED and submitted 

public comments are available in the public docket at (EPA-HQ-OPP-2008-0129) at 

www.regulations.gov. 

The Food Quality Protection Act of 1996 mandated registration review, where every 15 years the 

Agency reviews a pesticide to make sure that it will not cause unreasonable risks to human 

health or the environment when used as directed on product labeling. In the future, sulfometuron 

methyl will be reviewed again under the registration review program. 
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Table 11. Revised Summary of Labeling Changes for Sulfometuron Methyl 

(Changes From 2008 SMM RED Highlighted in Yellow) 

Description Amended Labeling Language 

For all Manufacturing Use Products 

“Only for formulation into a herbicide for the following use(s) [fill blank only with those uses that are being 

supported by MP registrant].” 

One of these statements may be added to a label to allow reformulation of the product for a specific use or all additional uses supported by a formulator or user 

“This product may be used to formulate products for specific use(s) not listed on the MP label if the formulator, user group, or grower has complied with U.S. EPA submission requirements regarding support of such use(s).” “This product may be used to formulate products for any additional use(s) not listed on the MP label if the 

formulator, user group, or grower has complied with U.S. EPA submission requirements regarding support of such use(s).” 

Environmental Hazards Statements Required by the RED and Agency Label Policies 

"Do not discharge effluent containing this product into lakes, streams, ponds, estuaries, oceans, or other 

waters unless in accordance with the requirements of a National Pollution Discharge Elimination System (NPDES) permit and the permitting authority has been notified in writing prior to discharge. Do not discharge effluent containing this product to sewer systems without previously notifying the local sewage treatment plant authority. For guidance contact your State Water Board or Regional Office of the EPA." 

End Use Products Intended for Occupational Use

PPE Requirements Established by the RED for WDG Formulations 

“Personal Protective Equipment (PPE)” “Some materials that are chemical-resistant to this product are” (registrant inserts correct chemical-resistant material). “If you want more options, follow the instructions for category” [registrant inserts A,B,C,D,E,F,G,or H] “on an EPA chemical-resistance category selection chart." “All mixers, loaders, applicators and other handlers must wear: Long-sleeved shirt and long pants, and Shoes plus socks.” See engineering controls for more requirements 
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PPE Requirements Established by the RED For Liquid Formulations 

“Personal Protective Equipment (PPE)” “Some materials that are chemical-resistant to this product are” (registrant inserts correct chemical-resistant material). “If you want more options, follow the instructions for category” [registrant inserts A,B,C,D,E,F,G,or H] “on an EPA chemical-resistance category selection chart." “All liquid mixers, loaders, applicators, and other handlers must wear: Long-sleeved shirt and long pants, and Shoes plus socks.” 

User Safety Requirements “Follow manufacturer's instructions for cleaning/maintaining PPE. If no such instructions for washables 

exist, use detergent and hot water. Keep and wash PPE separately from other laundry.” “Discard clothing and other absorbent materials that have been drenched or heavily contaminated with this 

product’s concentrate. Do not reuse them.” 

Engineering Controls for WDG and Granular formulations that permit aerial application 

“Pilots must use an enclosed cockpit in a manner that is consistent with the WPS for Agricultural Pesticides [40 CFR170.240(d)(6)].” 

User Safety Recommendations 

“User Safety Recommendations Users should wash hands before eating, drinking, chewing gum, using tobacco, or using the toilet. Users should remove clothing/PPE immediately if pesticide gets inside. Then wash thoroughly and put on clean clothing. Users should remove PPE immediately after handling this product. Wash the outside of gloves before removing. As soon as possible, wash thoroughly and change into clean clothing.” 
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Environmental Hazards “For terrestrial uses, except for under the forest canopy: Do not apply directly to water, or to areas where 

surface water is present or to intertidal areas below the mean high water mark. Do not contaminate water when disposing of equipment washwater or rinsate." “Exposure to (Brand Name) can injure or kill plants. Damage to susceptible plants can occur when soil particles are blown or washed off target onto cropland. Applications may not be made to soil that is subject to wind erosion when less than a 60% chance of rainfall is predicted to occur in the treatment area within 48 hours. Soils that are subject to wind erosion usually have a high silt and/or fine to very fine sand fractions. Soils with low organic matter also tend to be prone to wind erosion.” 

Restricted-Entry Interval for products with directions for use within scope of the Worker Protection Standard for Agricultural Pesticides (WPS) 

Basic REI Statement for all crops: “Do not enter or allow worker entry into treated areas during the restricted entry interval (REI) of 4 hours.” 

Early Entry Personal Protective Equipment for products with directions for use within the scope of the WPS 

“PPE required for early entry to treated areas that is permitted under the Worker Protection Standard and that involves contact with anything that has been treated, such as plants, soil, or water, is: 

* coveralls, * shoes plus socks, and * chemical-resistant gloves made of any waterproof material” 

Entry Restrictions for products having occupational uses on the label not subject to the WPS 

Entry Restriction for non-WPS uses applied as a spray:

“Do not enter or allow others to enter until sprays have dried.” Entry Restriction for non-WPS uses applied dry:

“Do not enter or allow others to enter until dusts have settled.” 

General Application Restrictions 

“Do not apply this product in a way that will contact workers or other persons, either directly or through 

drift. Only protected handlers may be in the area during application.” 
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Application Restrictions 

The following risk mitigation measures must be reflected in the directions for use: New maximum application rates for all formulations:Forestry (Including Deciduous, Conifers, Christmas Trees):  0.199 lb ai/A/application Non-Agricultural Rights of Way:  0.281 lb ai/A/application 

Other Application Restrictions (Risk Mitigation) 

“Applications may not be made to soil that is subject to wind erosion when less than a 60% chance of rainfall is predicted to occur in the treatment area within 48 hours. Soils that are subject to wind erosion usually have a high silt and/or fine to very fine sand fractions. Soils with low organic matter also tend to be prone to wind erosion.” 
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Spray Drift Droplet Size “Applications must be made using extremely coarse or coarser droplet size spectrum according to ASABE 

(S572) definition.” Wind Direction and Speed “Do not apply when wind speed is greater than 10 mph.” Temperature Inversion “Do not make aerial or ground applications into temperature inversions.” “Inversions are characterized by stable air and increasing temperatures with height above the ground. Mist or fog may indicate the presence of an inversion in humid areas. The applicator may detect the presence of an inversion by producing smoke and observing a smoke layer near the ground surface.” Additional Requirements for Ground Applications “For ground boom applications, apply spray at lowest height that is consistent with pest control objectives to minimize drift.” Additional Requirements for Aerial Applications “Spray must be released at the lowest height consistent with pest control objectives and flight safety.” “The spray boom should be mounted on the aircraft as to minimize drift caused by wingtip or rotor vortices. The minimum practical boom length should be used and must not exceed 75% of the wing span or 80% rotor blade diameter.” “Flight speed and nozzle orientation must be considered in determining compliance with the allowable droplet size spectrum.” “When applications are made with a cross-wind, the swath will be displaced downwind. The applicator must compensate for this displacement at the downwind edge of the application area by adjusting the path of the aircraft upwind.” 
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Buffer Zone Requirements For Ground Applications: 

“For broadcast ground applications, do not apply within 50 feet of aquatic vegetation (including, but not limited to, lakes, reservoirs, rivers, streams, marshes, ponds, estuaries, and commercial fish ponds), or water used as an irrigation source, or crops.” “For hand held spot treatment applications, do not apply within 30 feet of aquatic vegetation (including, but not limited to, lakes, reservoirs, rivers, streams, marshes, ponds, estuaries, and commercial fish ponds), or water used as an irrigation source, or crops.”For Aerial Applications: “Do not apply liquid formulations of [insert product] with fixed wing aircraft. Liquid formulations of [insert product] must be applied via rotary aircraft.” “Do not apply within 75 feet of aquatic vegetation (including, but not limited to, lakes, reservoirs, rivers, streams, marshes, ponds, estuaries, and commercial fish ponds), or water used as an irrigation source, or crops.”