Page 1 of 12 

### UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, D.C. 20460

OFFICE OF CHEMICAL SAFETY AND
POLLUTION PREVENTION



### MEMORANDUM

DATE: Marc h 19 , 2011

SUBJECT: FL AZASULFURON : Occupational and Residential Exposure/Risk Assessment
for Use on Citrus, Grapes, Sugarcane, Christmas Trees , and Industrial Vegetation Management

PC Code: 119011 DP Barcode: D 37 8633
Decision Number: 42525 3 Registra tion Number: 71512

- RI
Petition Number: 9F7666 Regulatory Action: NA Risk Assessment Type: NA Case Number: NA

T XR Number: NA CAS Number: 104040

- 78

- 0
MRID Numbers: NA 40CFR: NA

FROM: Cassi L. Walls

, Ph.D., Senior Biologist

R isk Assessment Branch III Health Effects Division (7509P)

THROUGH: Barry O’Keefe, ORE Team Leader

R isk Assessment Branch III Health Effects Division (7509P)

TO: Cassi L. Walls, Ph.D.

, Risk Assessor

R isk Assessment Branch 3 Health Effects Division (7509P)

The Registration Division (RD) requested that the Health Effects Division (HED) conduct an occupational expo sure and risk assessment for proposed first food uses of fl azasulfuron in/ on citrus, grapes, sugarcane and proposed uses on Christmas trees and industrial vegetation
management areas.Page 2 of 12 

### 1.0 Executive Summary

Flazasulfuron is a herbicide for control of certain broadleaf weeds and grasses which acts by inhibiting the acetolactate synthas e (ALS) biochemical process . It is currently registered for use on golf courses, sod farms, athletic fields, and commercial lawns

. A Section 3 registration is being requested by ISK Biosciences Corporation for the proposed first new food uses of
flazasul furon in/on citrus, grapes and sugarcane. Additionally, flazasulfuron is also being proposed for use on Christmas trees and industrial vegetation management in nonagricultural

areas

. ISK has submitted an application to register these uses on the propose d label ISK Flazasulfuron Herbicide (EPA Reg. No. 71512

- ), which is a water dispersible granule formulation containing a 25.0% active ingredient

.

Proposed Use Profile :

ISK Flazasulfuron Herbicide is proposed for use on citrus, grapes, sugarcane, Christma s trees

, and nonagricultural vegetation management areas

. Soil directed spray application for citrus and

grapes are proposed at rates of 0.03 3

– 0.045 lb ai/A/application with a maximum seasonal rate
of 0.15 lb ai/A

. Preharvest intervals (PHIs) are propo sed at 1 day for citrus and 75 days for

grapes. Over

- the

- top applications for sugarcane are pr oposed at rates of 0.014

– 0.023 lb ai/A/application with a retreatment interval (RTI) of 14 days. Post

- directed applications for sugarcane are proposed at rate s of 0.014

– 0.045 lb ai/A/application with a maximum seasonal
rate of 0.15 lb ai/A. The proposed PHI for sugarcane is 180 days. Over

- the

- top and soil directed spray applications are proposed for Christmas trees at rates of 0.033

– 0.045 lb ai/A/applicat ion.

Over

- the

- top applications must be made prior to spring bud break or when conifers are sufficiently hardened off. Application rates for vegetation management in nonagricultural areas are proposed at 0.047 lb ai/A/application with an RTI of 4 to 6 wee ks . These applications many not be made near residential properties or near sensitive desired plants.

It should be noted that RTIs are currently not provided specifically for citrus, grapes, or Christmas trees while maximum seasonal rates are not provide d for Christmas trees or nonagricultural areas. HED recommends that these use directions be included on the proposed
label.

Hazard Concerns:

Short

- and i ntermediate

- term inhalation risks are based on systemic effects observed at the LOAEL of 10 mg/kg/day (NOAEL of 2 mg/kg/day) from a 90

- day oral toxicity study in dogs. No short

- or intermediate

- term dermal hazard was identified. Since the inhalation endpoint is not based on developmental effects, t he average body weig ht of an adult (70 kilograms) was used in the exposure

assessment s. The cancer classification is “not like ly to be carcinogenic to humans. ”

FQPA : The adequacy of the flazasulfuron toxicity database is considered complete

. The
flazasulfuron risk assessment team evaluated the quali ty of the toxicity and exposure data and, based on these data, recommended that the FQP A Safety Factor be reduced to 1X

.

Occupational Exposure:Page 3 of 12 

### Occupational short

- term (1

- 30 days) and intermediate

- term (1

- 6 months) dermal and inhalation exposures are expected from flazasulfuron handler activities associated with both the proposed ag ricultural and Christmas tree uses. HED used data from the Pesticide Handlers Exposure Database (PHED) Version 1.1 as presented in the PHED Surrog ate Exposure Guide (8/98) to assess handler exposures (HED Science Advisory Council for Exposure (ExpoSAC) Standard Operating Procedure (SOP) No. 7, dated 01/28/1999). Since no hazard was identified for the dermal route of exposure, dermal risks were not assessed

. A Margin of Exposure (MOE) greater than 100 for the inhalation route is deemed adequate to protect occupational flazasulfuron
handlers. All handler scenarios resulted in MOEs greater than the level of concern (LOC) (i.e.,

MOEs ≥ 100) for inhala tion exposures and, therefore are not of concern. Agricultural Handlers:

Occupational short

- and intermediate

- term dermal exposures are expected from post

- application activities. However, since no hazard was identified for the dermal route of e xposure, dermal
risks were not assessed Agricultural P ost

- a pplication:

Restricted Entry Interval : The ISK Flazasulfuron Herbicide label proposes a 4

- hour reduced reentry interval (REI). In accordance with criteria for reduced REI candidates, an active ingredient cannot elicit reprodu ctive, developmental, neurotoxic or carcinogenic effects. Flazasulfuron elicits developmental effects, and therefore cannot be a candidate for a reduced REI. Per the Worker Protection Standard (WPS), chemicals classified as Toxicity Categories III
and IV require a 12

- hr restricted entry interval (REI). HED recommends that RD ensure that the
REI on the label be corrected to 12 hours.

Review of Human Research:

This risk assessment relies in part on data from studies in which adult human subjects were
int entionally exposed to a pesticide or other chemical. These studies, which comprise of the Pesticide Handlers Exposure Database (PHED), have been determined to require a review of
their ethical conduct and have received that review.

Residential Exposure:

This document only presents the assessment of the proposed new ag ricultural uses of
flazasulfuron

. N o residential uses are being reque sted at this time; therefore, a residential risk
assessment has not been conducted.

2.0 Hazard Characterization

2.1 Ha zard Profile

The hazard profile for flazasulfuron has not changed since the previous risk assessment was
written in November of 2005 . For complete details on the hazard profile refer to “ Flazasulfuron: Human Health Risk Assessment for the Proposed Uses o n Golf Courses, Sod Farms,Page 4 of 12 

### Professionally Managed Athletic Fields (College and Professional), and Commercial Lawns

. 

### ” 

### (D303573, Gerome Burke, 11/16/2005 ). The acute toxicity findings for technical flazasulfuron

are presented in Table 1.

Table 1. Acut e Toxicity Profile

– Flazasulfuron , TGAI

Guideline

No. Study Type MRID(s) Results Toxicity Category

870.1100 Acute oral

– rat 46220908 LD 50 > 5000 mg/kg (male and females) IV

870.1200 Acute dermal

- rat 46220909 LD 50 > 2000 mg/kg (male and females) III

870.1300 Acute inhalation

– rat 46220910 LC 50 > 5 mg/L (male and females) IV

870.2400 Acute eye irritation

– rabbit 46220911 Minimal conjunctivitis through 48 hours. Free by 72 hours. III

870.2500 Acute dermal irritation

– rabbit 46220912 No erythema, edema, or dermal
effects observed at application site. IV

870.2600 Skin sensitization

– guinea pig 46220913 Not a sensitizer

-



### No short

- or int ermediate

- term dermal hazard was identified, since dermal or systemic toxicity was not
seen in a subchronic dermal study in rabbits at dose levels up to the limit dose. Short

- and

i ntermediate

- term inhalation risks are based on liver toxicity (increase in deposition of brown pigments, glutamic pyruvic transaminase, creatine phosphokinase, inflammato ry cell infiltration, microgranulomas) observed at the LOAEL of 10 mg/kg/day ( NOAEL of 2 mg/kg/day) from a 90

- day oral toxicity study in dogs. An inhala tion absorption value of 100% was assumed, since the endpoint is based on an oral study. The average b ody weig ht of an adult (70 kilograms) was used in the assessment, since the effects are not a developmental study

.

HED’s LOC for the MOE is defined by the uncertainty factors that are applied to the assessment. HED applies a 10X factor to account for i nterspecies extrapolation and a 10X factor to account for intraspecies sensitivity. Therefore, the total uncertainty factor that has been applied to the non

- cancer risk assessment is 100 for occupational exposure. Occupational risks resulting in MOEs gre ater than or equal to 100 do not exceed HED’s LOC.

There was no evidence of carcinogenicity to humans based on lack of carcinogenic effects in the rat and mouse carcinogenicity studies and lack of a mutagenicity concern. Quantification of cancer risk is therefore not required. The cancer classification is “not likely to be carcinogenic to humans.”Page 5 of 12 

### FQPA : The adequacy of the f lazasulfuron toxicity database is considered complete

. The
flazasulfuorn risk assessment team evaluated the quality of the toxici ty and exposure data and, based on these data, recommended that the FQPA Safety Factor be reduced to 1 X

.

Applicable toxicological doses and endpoints for use in this occupational risk asses sment are presented in Table 2.

Table 2. Summary of Toxicologic al Doses and Endpoints for Flazasulfuron for Use in Occupational Human
Health Risk Assessments

Exposure/
Scenario Point of Departure Uncertainty/ FQPA Safety

Factors Level of
Concern for
Risk
Assessment Study and Toxicological Effects

Dermal
Short

- Term (1

- 30 days)

Interme diate

Term (1

- 6 months) NOAEL =

N/A (dermal absorption rate = 45%) UF A = N/A

UF H = N/A Residential:
LOC for MOE =

N/A 21

- day Dermal study
NOAEL > 1000 mg/kg/day.
This risk assessment is not required

Inhalation
Short

- Term (1

- 3 0 days)

and

Intermediate

Term (1

- 6 months) NOAEL = 2 mg/kg/day (inhalation absorption rate = 100%) UF A = 10x

UF H = 10x Occupational:
LOC for MOE =

100 90

- Day oral toxicity in (dog) LOAEL = 10 mg/kg/day based on changes in liver (increase in: depositi on of brown pigments, glutamic pyruvic transaminase, creatine phosphokinase, inflammatory cell infiltration, microgranulomas).

Cancer (oral, dermal, inhalation) Classification: No evidence of carcinogenicity to humans based on lack of carcinogenic effec ts in the rat and mouse carcinogenicity studies and lack of a mutagenicity concern

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. UF A = extrapolation from animal to human (interspecies). UF H = poten tial variation in sensitivity among members of the human population (intraspecies). MOE = margin of exposure. LOC = level of

concern

.



### 3.0 Summary of Proposed Uses

Flazasulfuron is a sulfonylurea herbicide for control of certain broad

- leaf weeds and gra sses, and acts by inhibiting the acetolactate synthase (ALS) biochemical process. A summary of the proposed new flazasulfuron uses is presented in Table 3 below.Page 6 of 12 Table 3. Use Profile for Proposed New Flazasulfuron Uses

Use Site Max

. Rate for Single

Appl. Max.

Rate

per Season Retreatment

Interval and
Maximum

No. of Applications PHI Application Method and
Instructions

ISK Flazasulfuron Herbicide [ EPA Reg. No 71512

- RI ]

Citrus 0.045 lb
ai/acre 0.15 lb
ai/acre Not reported 1

Not reporte d 1 day P re

- eme rgence and Post

emergence

Apply only as a directed spray to the soil beneath the trees using ground spray equipment

Use a non

- ionic surfactant at 0.25% v/v for post

emergence applications.

Grapes 0.045 lb
ai/acre 0.15 lb
ai/acre Not reported 1

Not repor te d 75 day s Pr e

- emergence and Post

emergence

Apply only as a directed spray to the soil beneath the vines using ground spray equipment

Use a non

- ionic surfactant at 0.25% v/v for post

emergence applications.

Sugarcane Over

- the

Top or

Post

directed :

0.02 3 lb

ai/acre 0.15 lb
ai/acre 14 days

Not reporte d 180 day s Apply prior to spiking or on ratoon up to 24 inches
tall at a 0.014 lb ai/A rate.

Use a non

- ionic surfactant
at 0.25% v/v.

Allow a 12 month interval

between the last application and the planting of the rotational

crop.

Post

directed :

0.045 lb
ai/acre 0.15 lb

ai/acre 14 days
Not reported 180 day s Apply to sugarcane that is 18 inches tall up through layby. Applications

should minimize contact
with the whorl of the

sugarcane.

Use a non

- ionic surf actant at 0.25% v/v.

Allow a 12 month interval
between the last application and the planting of the rotational

crop.Page 7 of 12 Table 3. Use Profile for Proposed New Flazasulfuron Uses

Use Site Max

. Rate for Single

Appl. Max.

Rate

per Season Retreatment

Interval and
Maximum

No. of Applications PHI Application Method and
Instructions

Christmas trees 0.045 lb
ai/acre Not
reporte d Not reported 1

Not reporte d NA Pre

- emergence and Post

emergence

Do not apply to conifer

se edbeds. Do not apply to trees within 1 year of seeding. May be applied

over

- the

- top to conifers prior to spring bud break

or when conifers are sufficiently hardend off. Directed sprays must be
made to conifers that have new growth or are not
sufficientl y hardened off. Directed sprays are preferred and

recommended to reduce phytotoxicity potential

Use a non

- ionic surfactant
at 0.25% v/v.

Uncultivated nonagricultural areas (airports, ditch banks, dry canals, highway, railroad and utility

rights

- of

- ways, industrial sites, storage areas, and warehouse areas) 0.047 lb
ai/acre Not
reporte d 4 to 6 weeks

Not reporte d NA Post

- emergence

Do not use near residential properties.

Use a non

- ionic surfactant
at 0.25% v/v.

1 A retreatment interval specifically for citrus and grapes was not provided. A generic retreatment interval was provided.



### General application information on the label states that pre

- emergence and post

- emergence applications should be made in 15 to 50 gallons of water per acre. For directed po st

- emergence sprays, a spray volume of 20 gallons or more per acre is recommended. Applications should be made using conventional low pressure ground spray equipment. Applications cannot be made aerially or through any irrigation system. The general lab el application restrictions also state that repeat applications may be made at 2 to 6 weeks after application. However, the label also states that split applications should be made at 4 to 6 weeks after the first application, and that sequential applicati ons are made on a longer term interval such as spring followed by a fall application.

4.0 Occupational Exposure and Risk

4.1 Handler Exposure and Risk

Che mical

- specific exposure data we re not submitted to s upport the proposed flazasulfuron uses

. W h en chemical

- specific mon itoring data are not available, i t is the policy of HED to use dataPage 8 of 12 

### from PHED Version 1.1 as presented in the PHED Surrogate Exposure Guide (8/98) 1 

### to assess handler exposures for regulatory actions. Additionally, typical HED stand ard values were used for the amount treated per day (ExpoSAC Policy # 9, 7/5/00).

Based upon the proposed flazasulfuron use patterns, HED assessed risks to occupational pesticide handlers in the following scenarios:

**•** 

### mixing/loading dry flowable powder t o support groundboom applications,

**•** 

### mixing/loading dry flowable powder to support groundboom applications,

**•** 

### applying sprays with groundboom equipment,

**•** 

### applying sprays with right

- of

- way sprayer equipment,

**•** 

### mixing/loading/applying sprays with backpack sprayers, and

**•** 

### wettable powder mixing/loading/appl ying with low pressure handwand.

Equations and Calculations:

Daily Exposure: Daily handler exposures are estimated for each applicable handler task with the application rate, the amount of acres treated in a day, a nd the applicable unit expo sure using the following equation :

Daily Exposure (mg ai/day) = UE (μ g /lb ai ) or (mg /lb ai) x AR (lbs ai/A ) x AT (A/day) x CF (as needed) (mg/1,000 μg)

Where:

Daily Exposure = Amount (mg ai/day) deposited on the surface of the skin that is available for dermal absorption or amount inhaled that is available for inhalation absorption,

UE = Unit e xposure value (μg /lb ai) or (mg/lb ai)

A R = Ap plication rate (lb ai/A) or (lb ai/gal ) based on maximum labeled rate

AT = Area treated (A/day) or Amount handled (gal/day)



### Daily Dose: Daily dose (inhalation or dermal) is calculated by normalizing the daily dermal or inhalation exposure value by body weight and accounting for dermal and i nhalation absorption.

Average Daily Dose (mg/kg/day ) = Body Weight (kg) Daily Exposure (mg ai/day) x Absorption Factor (%)

Where:

Average Daily Dose = Absorbed dose received from exposure to a pesticide in a given

scenario (mg pesticide active ingredient/kg body weight/day)

, Daily Exposure = Amount (mg ai/day) deposited on the surface of the skin that is available for dermal absorption or amount inhaled that is available for inhalation absorption, Absorption Factor = A measure of the amount of chemical that crosses a biological boundary such as the skin or lungs, and Body Weight = Body weight determined to represent the population of interest in a risk

assessment.

1 HED Science Advisory Council for Exposure [ExpoSAC] Policy .007, “Use of Values from PHED Surrogate
Table and Chemical

- S pecific Data” HED, OPP, 1/28/99Page 9 of 12 

### Margin of Exposure (MOE): The daily dermal dose and daily inhalation dose rec eived by

occupa tional handlers are compared to the appropriate point of departure (i.e., N OAEL) to assess the risk to occupational handlers for each exposure route. All MOE values are calculated separately for dermal and inhalation exposure lev els using the following eq uation :

MOE = Average Daily Dose (mg/kg/day ) N OAEL (mg/kg/day)

Where:

MOE = Margin of exposure value used by HED to represent risk or how close a chemical exposure is to being a concern (unitless),

ADD = Average daily dose is the absorbed dos e received from exposure to pesticide (mg/kg/day)

NOAEL = No Observable A dvers e Effect Level (mg/kg/day)



### HED’s LOC for the MOE is defined by the uncertainty factors that are applied to th e assessment. HED applies a 10X factor to account for interspec ies extrapolation and a 10X factor to account for intraspecies sensitivity. T herefore, t he total uncertainty factor that has been applied to the

non

- cancer risk assessment is 1 00 for occupational expo sure. Occupational risk s resulting in MOEs greater tha n or equal to 1 00 do not exceed HED ’s LOC

.

Short

- and intermediate

- term r isk estimate s for occupational handlers are included in Table 4

. A ll handler scenarios resulted in MOEs greater tha n the LOC (MOEs ≥ 1 00)

, and therefore a re not of concern

.

Table 4

. Summary Of Short

- and Intermediate

- Term Occupational Handler Exposures And Risks

Exposure
Scenario Crop Grouping Application

Rate a (lb ai/A) Area
Treated Daily b (A/day) Baseline
Inhalation c

Un it Exposure

(μg/lb ai) Baseline
Inhalation Dose

(mg/kg/day) Baseline
Inhalation

ST MOE d
(LOC ≥ 100) Baseline
Inhalation

IT MOE e (LOC ≥ 100)

Mixer/Loader

Mixing/Loading

Dry Flowable
for
Groundboom Applications Citrus

0.045 80 0.77 0.000040 2,200,000 51,000 Grapes Sugarcane

Christmas

Trees

Non

- crop 0.047 80 0.77 0.000041 2,100,000 48,000

Mixing/Loading

Dry Flowable
for Right

- of

Way Applications Non

- crop 0.047 40 0.77 0.000021 4,200,000 97,000

Applicator

Applying Sprays via
Groundboom Equipment (open cab) Citrus Grapes Sugarcane
Christmas

Trees 0.045 80 0.74 0.000038 2,300,000 53,000

Non

- crop 0.047 80 0.74 0.000040 2,200,000 50,000

Applying Sprays via Right

- of

- Way Non

- crop 0.0024 (lb ai/gal) 1000 (gal/day) 3.9 0 .00013 670,000 15,000Page 10 of 12 Table 4

. Summary Of Short

- and Intermediate

- Term Occupational Handler Exposures And Risks

Exposure
Scenario Crop Grouping Application

Rate a (lb ai/A) Area
Treated Daily b (A/day) Baseline
Inhalation c

Un it Exposure

(μg/lb ai) Baseline
Inhalation Dose

(mg/kg/day) Baseline
Inhalation

ST MOE d
(LOC ≥ 100) Baseline
Inhalation

IT MOE e (LOC ≥ 100)

Equipment

Mixer/Loader/Applicator

Backpack Christmas

Trees 0.0023 40 30 0.000039 2,300,000 52,000

Non

- crop 0.0024 40 30 0.00004 0 2,200,000 50,000
(lb ai/gal) (gal/day)

Low Pressure

Handwand Christmas

Trees 0.0023 40 1100 0.0014 62,0 00 1,400

Non

- crop 0.0024 40 1100 0.0015 59,000 1,400
(lb ai/gal) (gal/day)

a Application rates are the maximum application rates determined from p roposed labels for flazasulfuron

. b Amount handled per day values are HED estimates of acres treate d per day based on Exposure SAC SOP #9 “Standard Values for Daily Acres Treated in Agriculture,”

c Baseline Inhalation: no respirator.
d Inhalation ST MOE = ST NOAEL (87.5 mg/kg/day) / inhalation daily dose (mg/ kg/ day), where inhalation dose = daily
uni t exposure (μg/ lb ai) x applicatio n rate (lb ai/A) x area treated (A/day) x 100% inhalation absorption / body weight (70 kg adult). LOC = 100

e Inhalation ST MOE = STNOAEL (2 mg/kg/day) / inhalation daily dose (mg/ kg/ day), where inhalation dose = dai ly unit exposure (μg/ lb ai) x applicatio n rate (lb ai/A) x area treated (A/day) x 100% inhalation absorption / body weight (70 kg adult). LOC = 100



### 4.2 Occupational Post

- application Exposure and Risk

There is a possibility for agricultural workers t o have post

- application dermal exposure to flazasulfuron following its proposed new uses. However, a dermal hazard was not identified ; therefore, post

- application dermal exposures were not assessed.

Occupational Post

- application Inhalation

Based on the Agency's current practices, a quantitative post

- application inhalation exposure

assessment was not performed for flazasulfuron at this time primarily because of the low acute inhalation toxicity (Toxicity Category IV) and low vapor pressure ( < 1 x 10 - 7 

### t orr ). However, there are multiple potential sources of post

- application inhalation exposure to individuals performing post

- application activities in previously treated fields. These potential sources include volatilization of pesticides and resuspension o f dusts and/or particulates that contain pesticides. The Agency sought expert advice and input on issues related to volatilization of pesticides from its Federal Insecticide, Fungicide, and Rodenticide Act Scientific Advisory Panel (SAP) in December 2009, and received the SAP’s final report on March 2, 2010 ( http://www.epa.gov/scipoly/SAP/meetings/2009/120109meeting.html ). The Agency is in the process of evaluating the SAP report as well as available post

- application inhalation exposure data generated by the Agricultural Reentry Task Force and may, as appropriate, develop policies and procedures, to identify the need for and, subsequently, the way to incorporate occupational
post

- application inhalation exposure into the Agency's risk assessments. If new p olicies orPage 11 of 12 

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

- application inhalation ex posure assessment for flazasulfuron

.

Although a quantitative occupational post

- application inhalation exposure assessme nt was not performed, an inhalation exposure assessment was performed for occupational handlers. Handler exposure resulting from application of pesticides outdoors is likely to result in higher exposure than post

- application exposure. Therefore, it is ex pected that these handler inhalation exposure estimates would be protective of most occupational post

- application inhalation exposure scenarios.

Restricted Entry Interval: The ISK Flazasulfuron Herbicide label proposes a 4

- hour reduced reentry interval ( REI). In accordance with criteria for reduced REI candidates, an active ingredient cannot elicit reproductive, developmental, neurotoxic or carcinogenic effects. Flazasulfuron elicits developmental effects, and therefore cannot be a candidate for a reduc ed REI. Per the Worker Protection Standard (WPS), chemicals classified as Toxicity Categories III and IV require a 12

- hr restricted entry interval (REI). HED recommends that RD ensure that the
REI on the label be corrected to 12 hours.

5.0 Residential Exposure and Risk

5.1 Residential Handler and Post

- application Exposures and Risks

This document only presents the assessment of the proposed new ag ricultural uses of
flazasulfuron . No residential uses are being reque sted at this time; therefore, a resi dential risk
assessment was not necessary to conduct

.

Flazasulfuron is currently registered for use on golf courses and other non

- residential turf areas such as industrial parks, tank farms, sod farms, seed farms, professionally managed sports fields,

a nd commercial lawns. Post

- application short

- term dermal exposure s are expected to occur for recreational golfers or players of various sports who use a golf course or athletic field after flazasulfuron has been applied. However, since a dermal hazard was not identified, dermal exposures and risk were not assessed.

Based on the Agency's current practices, a quantitative post

- application inhalation exposure

assessment was not performed for flazasulfuron at this time primarily because of the low acute
inha lation toxicity (Toxicity Category IV) and low vapor pressure ( < 1 x 10 - 7 

### torr ). However, 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 Federal Insecticide, Fungicide, and Rodenticide Act 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 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 i nto the Agency's risk assessments. If new policies or procedures are developed, the Agency may revisit the need for a quantitative post

- application
inhalation ex posure assessment for flazasulfuron

.Page 12 of 12 

### 5.2 Spray Drift

Spray drift is always a potential sourc e of exposure to residents nearby to spraying operations. This is particularly the case with aerial application, but, to a lesser extent, could also be a potential source of exposure from the ground application method em ployed for flazasulfuron

. The Agen cy has been working with the Spray Drift Task Force, EPA Regional Offices and State Lead Agencies for pesticide regulation and other parties to develop the best spray drift management practices (see the Agency’s Spray Drift website for more information at http://www.epa.gov/opp00001/factsheets/spraydrift.htm). On a chemical by chemical basis, the Agency is now requiring interim mitigation measures for aerial applications that must be placed on product labels/labeling. The Agency has completed its evaluati on of the new database submitted by the Spray Drift Task Force, a membership of U.S. pesticide registrants, 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 a ir, orchard airblast and ground hydraulic methods. After the policy is in place, the Agency may impose further refinements in spray drift management practices to reduce off

- target drift with specific products with significant risks
associated with drift.