### Date: Subject:



### From:
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IntroductionUNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGTON, D . C. 20460

Marc h 27, 2014 OFFICE OF CHEMICAL SAFETY AND POLLUTION PREVENTION

Rimsulfuron: Occupational and Residential Exposure Assessment for the New Use on ALS-Tolerant "DuPont INZEN Z" Sorghum

PC Code: 129009 Decision No.: 473406 Pet ii tion No.: Risk Assessment Type: ORE T XRNo.:NA MRIDNo.:NA DP Barcode: 418152 Registration No .: 352-748, 352-816 Regulatory Action: Section 3 Case No.: NA CAS No.: 122931-48-0 40 CFR: § 180.478
Cassi Walls, Ph.D., Senior Biologist

### ~ 2

### W~ Risk Assessment Branch III Health Effects Division (7509P) Barry O'Keefe, Branch Senior Scientist 

## (:5, 0**~ ~**  Risk Assessment Branch III

- 

# r Health Effects Division (7509P)

Jennifer Tyler, ExpoSAC Reviewer

# vJ).l.t**-{l;[ij;z~** _ and 

# t
l'\ Monica Hawkins, ExpoSAC Revie

### f~ Exposure Science Advisory Comm ixpoSAC) I 

### HED Kab l e Davis, RM#25 Registration Division (7505P)

The Registration Division (RD) requested that the Health Effec ts Division (HED) conduct an occupational and residential exposure and risk assessment for the proposed new use of rimsulfuron on ALS- Tolerant "DuPont INZEN Z" sorghum. It is HED policy to use the best available data to assess exposure. Several sources of generic data were used in this assessment as surrogate data in the absence of chemical-specific data, Page I of 19including Pesticide Handlers Exposure Da tabase Version 1.1 (PHED 1.1 ); the Agricultural Handler Exposure Task Force (AHETF) database; and the Agricultural Reentry Task Force (ARTF) database. Some of these data are proprietary, and subject to the data protection provisions of the Federa l Insectici de, Fungicide, and Rodenticide Act (FIFRA). Note: Thi s memorandum was reviewed b y the Exposure Science Advisory Committee (ExpoSAC) on March 20, 2014.

Page 2 of 19Table of Contents 1.0 Executive Summary
. .. .. .. .. .. . .. ...... .. ....................................................................................... 4 2.0 Risk Assessment Conclusions and Recommendations
........ .. ............ .................................. 5 3.0 Hazard Characterization
... . ........... . ...................................... . ............................. . ... . .. ... . .. .. .. .. 6 4.0 Use Profile
......................................................................... . ..... . ........................................... 8 5
.0 Res idential Exposure and Risk Estimates ........................................................ ...... .. .. .. .. .. .. .. 9 5.1 SprayDrift
............ .. .............. .. ..... .. .......... .. ...... .. ...... . .. .. . .. .. .. ............................................. 9 5.2 Residential Bystander Post-Application Inhalation Exposure
.......................... .. ........... l 0 6.0 Occupational Exposure and Risk Estimates
...... .. ...... .. .. .................................................... 10 6.1 Occupational Handler Expos ure/Risk Estimates
............................................... .. .. ......... 10 6.2 Occupational Post-application Exposure/Risk Estimates
.............................................. 15 6.2.1 Occupational Post-app licati on I nhal ation Exposure/Risk Estimates
...................... 15 6.2.2 Occupational Post-application Dermal Exposure/Risk Estimates
.......................... 15 Appendix A. S umm ary of Occupational and Residential Non

- cancer Algor ithms
..................... 18

Page 3 of 191.0 Executive Summary Rimsulfuron is a sulfonylurea herbicide (Group 2) that works via inhibition of acetolactate synthetase enzyme found in susceptible plants. It has been registered for weed control on bushberr ies, caneberries, grapes, citrus, tree nuts, pome fruits, stone fruits, corn, chicory and non-cropland. DuPont Crop Protection (DuPont) has submitted a petition to add a new use for rimsulfuron herbicide on "INZENTM Z", a var iety of sulfony lurea tolerant sorghum, and to add the proposed crop to the DuPontTM Resolve® Herbicide (EPA Reg. No. 352-748) and DuPontTM Steadfast®XP Herbicide (EPA Reg. No. 352-816) product labels. The Resolve® Herbicide end

- use product is a water soluble granule (WG) formulation containing 25% rimsulfuron as the active ingredient (ai). The Steadfast ® Herbicide end

- use product is a WG formu l ation containing 15% rimsulfuron and 30% nicosulfuron as the active ingredients. Nicosulfuron exposure and risk wi ll be assessed in a separate document. Proposed Use Profile: DuPontTM Resolve® Herbicide and DuPontTM Steadfast® XP Herbicide end -u se produc ts are proposed to include a use on "IN ZENTM Z" , a variety of sulfonylurea tolerant sorghum. Applicati ons are made using ground and aerial equipment. The proposed pos temergent appl ication rates are 0
.012- 0.031 lb ai/ A with a maximum seasonal rate of 0.031 lb ai/ A , a retreatment interval (RTI) of 7 days and, a pre -h arvest interval (PHI) of 69 days. Handlers are required to wear the following personal protective equipment (PPE): long-sleeved shirt, long pants, shoes, socks, and chemical-resi stan t gloves. Hazard Concerns : The adequacy of the rimsul furo n toxicity database is considered complete. Short- and intermediate

term dermal and inhalat ion risks are based on systemic effects observed at the lowest observed adverse effect level (LOAEL) of 125 mg/kg/day and a no observed adverse effect level (NOAEL) of6.25 mg/kg/day) from a 90-day oral toxicity study in dogs. T he HASPOC has determined that the requirement for a subchronic inhalation toxic ity study and dermal study (TRX 0050008) has been waived. Since no inhalation absorption data are available, toxicity by the inhalation route is considered to be equivalent to the estimated toxic ity by the oral route of exposure. Since no dermal absorption data are available, a dermal absorption factor of 100% was use d for the exposure asses sment. Since the dermal and inhalation endpoint is not based on developmental effects, the average body weight of an adu lt (80 kilograms) was used in the exposure assessments. The cancer classification is "not likely to be carc inogenic to humans." The rimsulfuron risk assessment team evaluated the quality of the toxicity and exposure data and , based on these data, recommended that the Food Quality Protection Act (FQPA) Safety Factor be reduced to 1 X. The level of concern (LOC) for occupationa l dermal and inh alation risk assessments is a margin of exposure (MOE) of 100
.

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age 4 of 19Occupational Exposure: Occupational Handler E xposures: Occupational short- and intermediate- term dermal and inhalation exposures are expected from rimsulfuron handler activities associated with the proposed sorghum use. Since the dermal and inhalatio n endpo ints are based on the same study, the exposures were combined
. A MOE greater than 100 for the dermal, inhalation , and combined routes is deemed adequate to protect occupational rimsulfuron handlers. All handler scenarios resulted in MOEs greater than the LO C (i.e., MOE s 

### 2:: 1 00) for dermal, inhalation, and combined exposures and, th erefore are not of conc ern. Occupational Post-application Exposures: Occupational short

- and intermedia t e-term dermal exposures are expected from rimsulfuron post-application activities associated wi t h the proposed sorghum use. All post-application scenario s resulted in MOEs greater than the level of concern (LOC 

## = MOEs 

### 2:: 1 00) for dermal exposures and, therefore are not of concern. Based on the Agency's current practices , a quantitative non-cancer occupational post-application inhalatio n exposure assessment was not performed for rimsul f uron at this time. If new policies or procedures are p u t into place, the Agency may revisit the need for a quantitative occupa tional post-application inhalation exposure asses s ment for rimsulfuron. Restricted Entry Interval (REI) : The prop o sed 4-hour REI which appears on the proposed supplemental label is consistent with 4-hour REI on the master label , and is adequate to protect for worker exposure. Human Studies Review 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, which include studies from PHED 1.1, AH E TF, and the ARTF database are ( 1) subject to ethics review pursuant to 40 CFR 26 , (2) have received that review , and (3) are compliant with applicable ethics requirements. For certain studies, the ethics review may have included review by the Human Studies Review Board. Descriptions of data sources, as well as guidance on their use, can b e found a t the Agency website 1 • 

### 2.0 Risk Assessment Conclusions an d Recommendations There are no occupational risk estimates of concern associated with the proposed new sorghum use of rimsulfuron. All of the dermal, inhalation, and combined handler and post-application MOEs based on the labeled PPE are greater than the LOC of 100 based on the proposed labeled PPE.

1 http: //www .epa.gov/pesticides/ sci enc e /hand l er- exposure-data.htm I and http: //www. epa. gov/pe sticides/ science /post-app-ex pos ure-data
.htm I Page 5 of 19Residue Data Requ irements Dislodgeable Foliar Residue (DFR): In accordance with the updated Part 158 data requirements (2007), one or more DFR studies are required when a pesticide has residential or occupational uses that could result in post-application dermal exposure. As part of the recent revision to the Health Effects Division's 2012 Standard Operating Pro cedures for Residential Pesticide Exposure Assessment, HE D analyzed a number of D FR studies and selected a new default value for the fraction of the application rate available to be dislodged after a foliar application (FAR). This def ault value is 25% and is based on an analysis of 19 DFR studies where the FAR value ranged from 2% to 89%. This value is recommended for use in both residential and occupational post-application assessments. Of the analyzed DFR studies, the maximum FAR value seen was 89% or 3.6 times higher than the default residue transfer value. Therefore, the HED has decided that a calculated MOE of approximately 4 times higher than the level of concern (e.g., an MOE> 400 if the LOC 

## = 1 00) using the default dislodged residue values would provide an adequate margin of safety for any potentially higher residues seen in a chemical-specific DFR study (Guidancefor Requiring / Waiving TurfTran s ferrable Residue (I'TR) and Dislodgeable Foliar Residue ( DFR) Studies. 6/7/ 2012, Exposure Science Advisory Council). A DFR study is not required for rimsulfuron at this time since the dermal MOE is greater than 4 times the LOC based on default values for the fraction of application rate available for transfer after a foliar application. 

### 3 .0 H azard Characterization For the proposed new use, the toxicological database for rimsulfuron is sufficient for risk assessment purposes. All the requirements of the new Part 15 8 guidelines have now been submitted or waived. The recently submitted immunotoxicity, acute neurotoxicity and subchronic neurotoxicity studied are currently under review. HASPOC w aived the subchronic inhalation study. Acute Toxicity Technical rimsulfuron has low toxicity (Toxicity Category IV) via oral, dermal and inhalation route of exposures. It is a moderate eye irritant (Toxicity Category III) and is not a skin sensiti zer (Table 3
. 1).

Table 3.1 Acute Toxicity Profile o fRi msu l fu ron Guideline No. Stu dy Type Resu lts Toxicity Category 870.1100 Acute oral

- rat LDs o 

### = > 5000 mg/kg IV 870.1200 Acute dermal

- rat LD so = > 2000 mg/kg IV 870.1300 Acute inhalation

- rat LC so 

### = > 5.4 mg/L IV 870.2400 Acute eye irritation Moderate eye irritant III 870.2500 Acute dermal irritation Not an irritant IV 870
.2600 Skin sensitizati on N ot a s e ns itizer 

## --

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age 6 of 19Toxicological PODs Used for Risk Assessment The toxicity database indicates that target organs for rimsulfuron are the liver and kidney in the rat and dog, along with the testis and blood in the mouse and dog
. In the mouse, the stomach was also a target organ. Adverse changes in body weight and food consumption were observed in rats, mice and dogs
. Effects seen in the subchronic and/ or chronic toxicity studies in one or more species included d ecreased body weight and body weight gain, increased relative and/or absolute liver and kidney weights, diuresis (increased urine volume) , decreased liver enzymes and bilirubin and increased serum cholesterol, fatty change, hepatocellular hypertrophy , increased red b lood cell (RBC), hemoglobin and platelet concentration, increased incidences of dilation and cysts in the glandul ar stomach, degenerati on of the testicular artery and tunica albuginea, increased incidence of seminiferous tubule degeneration and increased numbers of spermatid giant cells present in epididymides in males. Rimsulfuron is not mutagenic and has been classified as "Not Likely to be Carcinogenic to Humans," based on the lack of evidence for carcinogenicity in studies conduc ted in rats and mice. In the developmental toxicity study in rats , no developmental toxicity was seen at the highest d ose tested
. In the developmental toxicity study in rabbits, and in the two generation study in rats, developmental/offspring toxicity was seen in the presence of maternal/ systemic toxicity of comparable severity, and at similar dose levels. Consequently, there is no quantitative or qualitative evidence of increased susceptibility following pre - and/ or postnatal exposures , and there are no concerns or residual uncertainties. There was no evidence of neurotoxicity or immunotoxicity in the recently submitted studies which have undergone preliminary evaluation and are currently under detailed review. Therefore , HED has concluded that the FQPA Safety Fac tor should be reduced to 1 X. The LOC for occupational dermal and inhalation risk assessments is an MO E of 100. The endpoint for dermal and inhalation risk assessments for occupational workers was chosen from the 90-day oral study in the dog, and was based on kidney effects. A summary of the toxicological endpoints and doses used in the non-occupational and occupational risk assessment for rimsulfuron is provided in Table 3.2.

Table 3.2. Toxic olo!!ic a l Doses a n d E nd poi n ts Used i n Occ up a tio na l R isk Assessment of Rimsulf u ron. E xp osure/ Po in t of Unce r tai n ty LOC for R isk Study and Toxicological Sc enario Departure Factors Assess ment Effects Dermal NOAEL=6.25 UF A= lOx Occupational 90 Day Toxi c ity

- Dog Short- (1-30 Days) mg/ kg!day UFH = lOx LOC for MOE LOA E L= 125 mg!kg!day, based on and Intermed i ate- DAF= 100% = 100 kidn ey e ff e cts including increased Tenn (I- 6 urinary volume, increased kidney Months) weights, and decreased osmolality
.

P age 7 of 19Tab le 3 .2. Toxicolou ica l Doses a nd E ndp oi nts Use d i n Occ up a ti o n a l Risk Assessme n t of Rimsu l f u ron. Exposure/ Po int of U n cer t ain ty LOC fo r R isk Stu dy and Toxicological Scenario Depa r t u re Facto r s Assessment Effects In

halation NOAEL= 6.25 UFA = I Occupational Short- (1

- 30 Days) mg/kg/day UF H"" l O x LOC for MOE and Intermediat e - = 100 Term(I-6 Months) Cancer (oral, Rimsulfuron is classified as "not likely to be carcinogenic to humans" due to the absence o f dermal, inhalation) tumors in rat a!ld mouse carcinog enic ity studies
. OAF = dermal absorption factor, LOAEL = low e st observed adverse e f fect level, LOC = level of concern, MOE = margin of exposure, NOAEL = no observed adverse effect level, UF A = uncertainty factor for extrapolation from animal to human (interspecies) and UFH = uncertainty fac tor for potential variation in sensitivity among members of the human population ( i ntraspecies). Absorption S ince no dermal absorption data are available, a dermal absorption factor of 100% was used for the exposure assessment. Since no inhala tion absorption data are available, toxicity by the inhalation route is considered to be equivalent to the estimated tox icity by the oral route of exposure . Body Weight The standard body weight for the general population (80 kg) was used for all exposure scenarios covered in this risk assessment since the endpoints selected were not deve lopmental and/or fetal ef

fec t s. 

### 4.0 Use Profile The proposed use pattern for rimsu lfuron on sorghum is summarized in Table 4.1.
T ab le 4.1. Su m mary of D irectio ns for Use of R i msu l f ur o n. Formu latio Max. A pp lic. T imi ng , Appl ic. Max. No. RTP Seasona l P HI Use Directions and n Rate App li c . Ap pli c. an d Equipme nt (EPA Reg. J b ai/A per Season ( d ays) Rate (days) Limitations No.) l b a i /A Sulfonyl-Tolerant Varieties of Sorghum "I NZENTM Z"

Page 8 of 19Ta ble 4.1. Summary of Directions f or Use of R ims u l f uro n. Formulatio Applic. T im i ng, n and Equ ipment [EPA Reg. No.) Postemergence, 4

- 20 inches tall (Y3 Steadfast ®

- V7 s tage) ; XP 15%SG Aerial , Broadcast, [352-8 16] foliar; Ground equipment only. Postemergence, 4

- 20 inches tall (V3

- Y7 stage); Resolv e® 25%SG Aerial , Broadcast , [352-748] foliar ; Ground equipment only. ' 1 Rl I = Retreatment mterva l 1 PHI 

### = Preharvest interval. App li c . Max. No
. Rate A p p li c. lb a i /A pe r Seaso n 0.012 (1.25 oz/A) to 2 0.016 (1.67 oz/A) 0.016 ( 1.0 oz/ A) to 2 0.031 (2.0 oz/A ) Max. RTJ 1 Seasonal PHI Use Directio n s and Ap p lic. (days) Rate (days) Lim itations l b a i /A Do not apply through any 0
. 0 16 irrigation system. Aerial 7 (1
. 67 oz/A) 69 application is not permitted in New York State or California
.
Do not appl y through an y 0
. 03 1 irrigation system. Aerial 7 (2.0 o z/ A) 69 application is not permitted in New York State or California
.

The proposed use pattern for Steadfast®XP Herbicide on sulfo ny l -tolerant sorghum is to apply at a maximum rate of 1
. 67 

### ozl A/season (0
.0 16 lb ai/A/season) to provide selective postemergence grass and broadleaf weed control. The annual rate may be applied in two sequential treatments; with a minimum of 7 days between app li cations
. A preharve st interval (PH I) of 69 days has been proposed for sorghum grain and s tov er. The proposed use pattern for Resolve® Herbicide on sulfonyl-tolerant sorg hum is to apply at a maximum rate of2
. 0 ozJA/season (0.031 l b ai/A/season) to provide selec tive postemergence grass and broadleaf weed contro l. The annual rate may be applied in two sequential treatments; with a minimum of 7 days between applications
. A PHI of 69 days has been proposed fo r sorghum grain and s tover. 

### Persona l Protect ive Equipment (PPE): The PPE for S teadfast ®XP and Reso lve®Herbicides is long

- sleeved shirt, and long pants, shoes plus socks, and chemical resistant gloves
. 

### 5
. 0 Residential Exposure and Risk Estimates There are no existing or proposed uses for rimsulfu ron in residential settings, and therefore a residential exposure assessment was no t conduc ted. 

### 5.1 Spray Drift Spr ay drift is always a potential source of expo sure to residents nearby to spraying operations. T hi s i s particularly the case wi th aerial application, but, to a lesser extent, could also be a potential source of exposure from the ground application method employed for rimsulfuron. The Agency has been working with the Spray Drift Task Forc e, EPA Reg i onal Offices and State Lead Agencies for pes ticide regu l ation and other parties to develop the best spray drift
Page 9 of 19management practices (see the Agency's Spray Drift website for more information 2 • The Agency has completed its evaluation of the new database submitted by the Spray Drift Task Force, a membership of U.S. pesticide reg i strants, and is developing a policy on how to appropriately apply the data and the AgDRIFT computer model to its risk assessments for pesticides applied by air, orchard airblast a nd ground hydraulic methods. After the policy is in place, the Agency may impose further refinements in spray drift management practices to reduce otT-target drift with specific products with significant risk estimates associated with drift. Although a quantitative residential post-application inhalatio n exposure assessment was not performed as a result of pesticide drift from neighboring treated agricultural fields, an inhalation exposure assessment was performed for flaggers. This exposure scenario is representative of a worse case inhalation (drift) exposure and may be considered protective of most outdoor agricultural and commercial post-application inhalation expo sure scenarios. 5
. 2 Resident ial Bystander Post-App l ication Inhalation Exposure Based on the Agency's current prac tices, a quantitative post-a p plication inhalation exposure assessment was not performed for rimsulfuron at this time primarily because of the low acute inhalation toxicity (T oxicity Category IV) , low vapor pressure (1.13x 1 

## o- 8 mm Hg at 25 °C), and the low proposed use rate (0.031 lb ai/ A). However, volatilization of pesticides may be a source of post-application inhalation exposure to individuals nearby p esticide applications. The Agency sought expert advice and input on issues related to volatilization of pesticides from its Federal Insecticide , Fungicide, and Rodenticide Act Scientific Advisory Panel (SAP) in December 2009, and received the SAP's final report on March 2, 20103

. The Agency is in the process of evaluating the SAP report and may, as appropriate, develop policies and procedures to identify the need for and, subsequently, the way to incorporate post-application inhalation exposure into the Agency's risk assessments. If new pol icies or procedures are developed, the Agency may revisit the need for a quantitative post-app lication inhalation exposure assessment for rimsulfuron. 6 . 0 Occupational Exposure and Risk Estimates 6 . 1 Occupational Han d ler Exposure/Risk Estimates HED uses the term handlers to describe those individuals who are involved in the pesticide application process . HED believes that there are distinct job functions or tasks related to applications and exposures can vary depending on the specifics of each t ask. Job requirements (amount of chemical used in each application), the kinds of equipment used, the target being treated, and the level of protection used by a handler can cause exposure levels to differ in a manner specific to each application event. Based on the anticipated use patterns and current labeling, types of equipment and techniques that can potentially be used, occupational handler exposure is expected from the proposed uses.

2 Available:**hlil~t:£. ~\v** **epu~lli)Y op** **pOOOO** I ! lactshe e ts !spralf. dr ill.bJ!!.l 3 Available: http: //www. epa . gov/ scipoly/ SAP / mee tings/2 009/ 120 I09meetin g. html Page 10 of 19The quantitative exposure/ri sk assessment developed for occ u pational hand lers is based on the following scenarios:

• Mixer/Loader of SG formulation for groundboom application to sorghum, • Mixer /Loader of SG formulation for aerial app li cation to sorghum, • Applicator of liquid formulation for groundboom app li cati on to sorghum, • Applicator of liquid formu l ati on for aeri al application to sorghum, and • Flagging to support aerial spray applications. Occupational Handler Exposure Data and Assumptions A series of assumptions and exposure factors served as the basis for completing the occupational handler risk assessments. Eac h assumption and factor is detailed below on an individual basis. Application Rate: The maximum single application rate listed on the Resolve® SG Herbicide [EPA Reg. No. 352- 748 ] label is 0.031 l b ai/A, and is cons idered protective of the proposed application rates listed on the Steadfast®XP 15% SG [ 352-816 ] l abel. Unit Exposures: It is th e policy ofHED to use the best available data to assess handler exposure. Sources of generic handler data, used as surrogate data in the absence of chemica l -specific data, include PHED 1.1 and the AHETF database
. Some of these data are proprietary (e.g., AHETF data), and subject to the data protection provisions ofFIFRA. The standard values recommended for use in predicting handler exposure that are used in this assessment, known as "unit exposures", are outlined in the "Occupa tional Pesticide Handler Unit Exposure Surrogate Reference Ta ble4 ", which, along with additional information on HED policy on use of surrogate data, including descriptions of th e various sources, can be found at the Agency webs ite 5

. Area Treated or Amount Handled: The area treated or amount handled is based on guidance in HED ExpoSAC Policy 9
. 1. Refer to Table 6.1.1 for these assumptions for each scenario. Exposure Duration: HED classifies exposures from 1 to 30 days as short- term and exp osures 30 days to six months as intermediate-term. Exposure duration is determined by many things , including the exposed population, the use site, the pest pressure t r iggering the use of the pesticide, and the cultural practices surrounding that use site
. For most agricultural uses, it is reasonable to believe that occupational handlers will not apply the same chemical every day for more than a one-month time frame; however, there may be a large agribusiness and/o r commerc i al applicators who may app ly a product over a period of weeks (e.g., completing multiple applications for multiple clients within a region)
.

4 Available: http: //www.epa . gov/ oppOOOO I/science / handler-exposure-table.pdf 5 A vai !able: http: //www .epa .gov/ pesticides/ science / hand ler-exposure-data
.html

Page II of 19According to the proposed label, one application on sorghum is allowed per year at the maximum rate of0.031 lb ai/A, resulting in short-term handler exposures. Two sequential applications may be made at a maximum s easonal rate of 0.031 lb ai/A/growing season. HED typ icall y assumes commercial applicators use rimsulfuron for longer durations (> 1 month). Since the short- and intermedia te -term PODs are the same and therefore, only a short-term handler exposure was estimated which is considered protective of intermediate-term exposures. Lon g-term exposures are not expected; therefore, a long-term assessment was not conducted. Mitigation/Personal Protective Equipment: Estimates of dermal and inhalation exposure were calculated for various leve ls of PPE. Results are presented for labeled PPE which includes "basel ine'' plus gloves, defined as a single layer o f clothing consisting of a long sleeved shirt, long pants, shoes plus socks, and no respirator. The rimsulfuron product labels direct mixers, loaders, applicators and other handlers to wear lon gsleeved s hirt , long pants, shoes, socks, and chemical- resistan t gloves. Occupational Handler Exposure and Ri sk E stimate Equations The algorithms used to estimate exposure and dose for occupational handlers can be found in Appendix A. Combining Exposures/Risk Estimates: Dermal and inhalation risk estima tes were combined in this assessment, since the toxicological effects for these exposure routes were similar. Dermal and inhalation risk estimates were combined using the following formula: Total MOE ; Point of Departure (mg!kglday) 7 Combined dermal+ inhalation dose (mglkg/day) Summary of Occupational Handler Non

- Cancer Exposure and Risk Es timate s All of the MOEs for the occupational han d ler's dermal, inhalation, and combined exposures are greater than 100 at labeled PPE and therefore are not of concern. Table 6.1.1 summarizes the rimsulfuron occupational handler exposures and risks. The Agency matches quantitative occupational exposure assessment with appropriate characterization of exposure potential. While HED presents quantitative risk estimates for human flaggers where appropriate, agricultural aviation has changed dramatically over the past two decades. According the 2012 National Agricultural Aviation Association (NAAA) survey of thei r membership, the use o f GPS for swath gu idance in agricultural aviation has grown steadily from the mid 1990's. Over the same time period, the use of human flaggers for aerial pesticide applications has decreased steadily from**15 %**  in the late 1990's to only 1% in the most recent (20 12) NAAA survey. The Agency will continue to monitor all available information sources to best assess and characterize the exposure potential for human flaggers in agricultural aerial applications. HED has no data to assess exposures to pi lots using open cockpi ts. The only data available is for exposure to pilots in enclosed cockpits. Therefore, risks to pilots are assessed using the engineering control (enclosed cockpits) and baseline attire (long-sleeve shirt, lon g pants, shoes, and socks); per the Agency's Worker Protection Standard stipulations for engineering controls,
Page 12 of 19pilots are not required to wear protective gloves for the duration of the application. With this level of protection , there are no risk estimates of concern for applicators.

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age 13 of 19Table 6. 1. 1. STand lT Occ u pati ona l Ha nd ler Expos u re and Risk Estimates for Rimsu lfuron Derm a l Un it I n h alation Unit

Expos u re Expos u re Max imum Area Derma l Inha lation Exposure Scenario Crop (Jlg/lb a i) 1 (Jlg/lb ai) 1 Ap p licat ion Rate2 Basel ine ( lb a i /A) Baseline+ G loves (no respirator)
Aerial (SG form.) So rghum 51.6 8.96 Groundboom (SG form .) 51.6 8
. 96
Aerial (liquid form
.) So rghum 2
. 0 8 0.004 9 Groundboom (liquid form.) 16. 1 0.34 Flagger Sorghum 12.0 0.35

Based o n the " Occupational Pesticide Handler Un it Ex posure Surrogate Reference Table Based on registered or proposed label (Reg. No. 352-748) 3 Exposure Science Advisory Council Policy #9
. 1. Mixer/Loa der 0.031 O.D31 Applicator 0.0 3 1 O.D3 1 Flagger 0.03 1 Treated Da il r (A/day) Dose MOE5 Dose (mglkglday) 4 (mglkglday) 6
1200 0
. 024 260 0.0042 200 0
. 0040 1,600 0.00070
1200 0. 00094 6, 7 00 0.0000022 200 0
. 0013 5 , 000 0.000027
350 0.0016 3 , 800 0.000048

4 Dermal Dose = Derma l Unit Exposure (f.l g/

lb ai) x C onversion Factor (0.001 mg/)Jg) x Application Rate (lb ai/acre) x Area Treated ( Nday) x DAF {100%) + BW (80kg)
. 5 Dem1al MOE = D ermal NOAEL (6
. 25 mg!kg/day) + Dermal Dose (mg/kg/day). 6 Inhal a tion Dose = Inhalati on Unit Exposure (j.tg/lb ai) x Conversion Factor (0
.001**mg/~tg)** x Application Rate (lb ai/acre) x Area Treated (Nday) + BW (80kg)
. 7 Inhalation MOE = Inhalation NOAEL (6.25 mg!kg!day) +Inhalation Dose (mg/kg!day )
. 8 Total MOE= NOAE L (mg/kg/ day) + Dermal Dos e + Inhalation Dose.

Page 14 of 19 MOE7

1 , 500 9 , 000 2,800,000 240, 000
1 30,000 • Total i
! MOE8

220 j 1 ,400 6,700 1 , 000
3 , 800

### 6.2 Occupational Po st-application Exposure/Risk Estimates HED uses the term post-application to describe exposures that occur when individuals are present in an environment that has been previously treated with a pesticide (also referred to as reentry exposure). Such exposures may occur when workers enter previously treated areas to perform job functions, including activities related to crop production, such as scouting for pests or harvesting. Post-application exposure levels vary over time and depend on such things as the type of activity , t he nature of the crop or target that was treated, the type of pesticide application, and the chemical's degradation properties. In addition, the timing of pesticide applications, relative to harves t activities, can greatly reduce the potential fo r post-application exposure. 6.2.1 Occupational Post-application Inhalation Exposure/Risk Estimates Based on the Agency's current practices , a quantitative post-application inhalation exposure assessment was not performed for rimsulfuron at this time primarily because of the low acute inhalation toxicity (Toxicity Category IV), low vapor pressure (1.13xl0- 8 mm Hg at 25 °C), and the low proposed use rate (0.031 lb ai/ A). However, there are multiple potential sources of po stapplication inhalation exposure to individuals performing post-application activiti es in previously treated fields. These potential sources include volatilization of pesticides and resuspension of du sts and/or particulates that contain pesticides. The Agency sought expert advice and input on issues related to volatilization of pesticides from its Federal Insecticide, Fungicide, and Rodenticide Act Scientific Advisory Panel (SAP) in December 2009, and received the SAP's final report on March 2, 2010 6

. The Agency is in the process of evaluating the SAP report as well as available post-application inhalation exposure data generated by the ARTF and may , as appropriate, develop policies and procedures, to identify the need for and, subsequently, the way to incorporate occupa tional po st-application inhalation exposure into the Agency's ri sk assessments. If new policies or procedures are put into place, the Agency may revisit the need for a quantitative occupational post-application inhalation exposure assessment for rimsulfuron. Although a quantitative occupational post-application inhalation exposure assessment was not performed, an inhal ati on exposure assessment was performed for occupational/commercial handlers. Handler exposure resulting from application of pesticides outdoors is likely to result in higher exposure than post-application expos ure . Therefore, it is expected that these handler inhalation exposure estimates would be protective of mo st occupational post-application inhalation exposure scenarios. 6.2.2 Occupational Post-application Dermal Exposure/Risk Estimates Occupational Post-application Dermal Expos ure Data and Assumptions A series of assumptions and exposure factors served as the basis for completing the occupational post-application risk assessments. Each assumption and factor is detailed below on an individual basis.

6 Available: http: //www .ep a.gov/scipoly/ SAP / meetings/2009/ 120 I 09meeting.htm I Page 15 of 19Exposure Duration: HED classifies exposures from 1 to 30 days as short-term and exposures 30 days to six months as intermediate-term. For rimsulfuron, based on the proposed sorghum use, short- and intermediate

- exposures are expected
. Transfer Coefficients: It is the policy of HED to use the best available data to assess post
- application exposure. Sources of generic post-application data, used as surrogate data in the absence of chemicalspecific data, are derived from ARTF exposure monitoring studies, and, as proprietary data, are subject to the data protection provisions of FIFRA. The standard values recommended for use in predicting post-application exposure that are used in this assessment, known as "transfer coefficients", are presented in the ExpoSAC Policy 3 7 " which, along with additi onal information about the ARTF data, can be found at the Agency website 8 • Table 6.2.2.1. Anticipated Post- Ap pli cat io n Activit ies a nd De rmal T r a n sf e r C oe ffi c ients. Poli cy Crop C r op Fo li age Tra n sfer P rop osed Crops Gro up C o e ffi c ie nts Activities C a tegory He ig ht D e n sity (c m2/hr ) High Full 210 Scouting Field I row Low Full Sorghum, grain crop, tall High Full Low Full 70 Hand weeding Application Rate: The maximum single application rate listed on the Resolve® SG Herbicide [EPA Reg. No. 352

- 748] label is 0.031 lb ai/A, and is considered protective ofthe proposed application rates listed on the Steadfast® XP 15% SG [352-816] label. Exposure Time: The average occupational workday is assumed to be 8 hours. Dislodgeable Foliar Residues : Chemical-specific dis lodgeab le fo li ar res idue data have no t been submitted for rimsulfuron. Therefore, this assessment uses HED's default assumption that 25% of the application is avai l able for transfer on day 0 following the app licat i on and the res idues dissipate at a rate of 10% each following day
. Occupational Post-application Dermal Exposure and Risk Estimate Equations The algorithms used to estimate non-canc er exposure and dose for occupati onal post
- application workers can be found in Appendix A.

7 Available: http: // www.epa.gov/pesticides/ science / exposac policy 3.pdf 8 Available: http: //www.epa.gov/pesticides/ scienc e / pos t-ap p-exposure-data
.html

Page 16 of 19Occupational Post-application Dermal Ris k Estimates The dermal MOEs for each activity scenar i o using default assumptions are above the LOC of 100 on Day 0 and therefore , are not of conc ern (Table 6.2
. 2
. 2)
. Furthermore, a DFR study is no t required for rimsulfuron at this time since the dermal MOE is greater than 4 times the LOC based on default values for the fraction of application rate available for transfer after a foliar app lication. This decision of no t requestin g a DFR s tudy may need to be reconsidered if there is a chang e in use patterns for rimsulfuron
. T able 6
. 2.2.2. Occupational Post

- app li cat ion Non

- Cancer Exposure and Risk Estimates for Rimsulfuron. Crop/Site Activ ities Transfer Coefficient DFR 1 Dermal Dose MOE3 (cm 2/hr) (mg/kg/day) 2 Short- and Intermediate- term Sorghum Scouting 210 0
. 0869 0.0018 3 ,400 Hand Weeding 70 0. 0 869 0
. 00061 10 ,000 I DFR = Application Ra te x F x ( I·D)' x 4
. 54E 8 j.tg/ lb x 2 .47E ·8**acr e/e** **;** where F = 0.25 an d D = 0
. 10 per da y 2 Daily De rmal Dose= (DF R (j.tg/ cm 2) x Transf er Coeftici ent x 0.00 1 m g/

j.tg )< Slu s/

day x dermal ab s orpti on (1 00% ) ) + BW ( 80kg)
. 3 MO E = POD (6. 5 mg!kg/day) I Dai l y Dermal Dose
. Restricted E ntry Interval The currently registered product label lists a REI of 4 hours. P R Notice 95-03 on the Reduced REI policy (3

- May-1995) does not list rims ulfuron as an active ingredient approved for a 4-hour REI. However, PR 95

- 03 allows a 4-hour REI provided that end

- use products meet the following reduced risk cr iteria: (1) The active ingredient is in T oxicity Category III or IV based upon data for acute dermal toxicity , acute inhalation toxicity , p rimary skin irritation, and primary eye irritation. (2) The active ingredient is not a derm a l sensitizer. (3) The ac tive ingredient is not a cholinesterase inhibitor. (4) The active ingredient is not associated with known reproductive, developmental, carcinogenic , or neurotoxic e f fects
. (5) EPA does not possess incident information that is "definitely" or "probably " related to the po s t
- applica tion exposures to the active ingredient. The label REI i s typically based on the acu te toxicity of technical chemical. Under the WPS , active ingredients cl assified as Toxicity C at egory IV for Acu te Dermal and Primary Skin Irri t ation are assigned a 4-hour REI; therefore , the 4-hour REI on the proposed label is acceptab le and considered appropriate to protect agricultural workers from post-application exposures to rimsul furon.

Page 17 o f 19Appendix A . Summary of Occupational and Residential Non·cancer Algorithms Occupational Handler Algorithms Potential daily exposures for occupational handlers are calculated using the following formulas:
where: E UE AR A 

## =
= = E = UE 

### *AR *A* 0
. 001 mg /ug
exposure (mg ai/day), unit exposure (!lg ai/lb ai), maximum application rate ac cording to proposed label (lb ai A or lb ailgal), and area treated or amount handled (e.g., A/day, gal/day). The daily doses are calculated using the following formula:

where: ADD 

## = E 

## = AF BW 

### = ADD= E*AF 

### BW
average daily dose absorbed in a given scenario (mg ai/kg/day), exposure (mg ai/day), absorption factor (dermal and/or inhalation), and body weight (kg). Margin of Exposure: Non-cancer risk estimates for each application handler 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 and inhalation dose received by occupational handlers are compared to the appropriate POD (i.e., NOAEL) to assess the risk to occupational handlers for each exposure route. All MOE values are calculated using the following formula:

where: MOE 

## = POD ADD 

## = POD A10E= ADD margin of exposure: value used by HED t o represent risk estimates (unitless), point of departure (mglkg/day), an d average daily dose absorbed in a given scenario (mg ailkg/day). Occupational Post-application Algorithms Potential daily exposures for occupational post-application workers are calculated using the following formulas: DFR, = AR 

### *

# F*(l-D/*(4.54£8~!) *(2.4 7E -8

# c~**)** Page 18 of 19where: DFRt AR F D t

where: E TC DFRt ET =

= 

## =

= = 

### = dis lodgeab le foliage residue on day "t"**(~-tg/cm ),**  application rate (lb ai /acre), fraction of ai re ta in ed on fo liage or 25% (unitless), fract i on of residue that dissipates daily or 10% (unitless), and number of days after app licati on day (days). 

### E = TC 

## * DFR 1 

## * ET 

## * 0.001 mg ug exposure (mg ai/day), transfer coefficient (cm2 /hr), dislodgeable foliar residue on day "t" (!lg/cm 2), and exposure time (hours/day). The daily doses are calculated using the following formula:

where: ADD 

### = E AF 

### = BW 

### = ADD = E*AF 

### BW
average daily dose absorbed in a given scenario (mg ai/kg/day), exposure (mg ai/day), absorption factor (dermal and/or inhalation), and body weight (kg). Margin of Exposure: Non-cancer ri s k estimates for each scenario are calculated using a Margin of Exposure (MOE), which is a rati o of the tox icological endpoint to the dai ly dose of concern. The dail y dermal dose received by occupational post
- application workers is compared to the appropriate POD (i .e., NOAEL) to assess the risk to occupat i onal post-application workers
. All MOE values are calcul ated using the fo ll owing form u l a:

where: MOE 

## = POD ADD 

## = POD MOE= ADD
margin of exposure: value use d by HED to represent risk est imates (unitless), point of departure (mg/kg/day), and average daily dose absorbed in a given scenario (mg ai/kg/day).

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