### UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGTON, 

### D.C. 20460



### Date:

Subject: September 18, 2013 OFFICE OF CHEMICAL SAFETY

AND POLLUTION PREVENTION



### Trinexapac-ethyl. Preliminary Occupational and Residential Exposur e/Ri s k

Assessment for Registration Review

PC Code: I 12602

Decision No.: lf';3f'1?;

Petition No.: DP Barcode: 

### D4/.J030 Registra t ion No.: Regulatory Action: Reg Rev iew

Case No.: 7228 

### Risk Assessment 

### Type: OccupationaVResidential Exposure Assessment

T XRNo.: NA CAS No.: 95266-40 -3

40CFR: MRIDNo.: NA



### From:

Through:

To:

Introduction Monica Hawkins

, Ph.D., M.P.H., Environmental Health ScientistJYl&v\J., 'Ctlt.,

# ~**~** Risk Assessment Branch VI

Health Effects Division (7509 P )

Felecia Fort, Branch Chief 

# --:l**/)~~** 

# /-

Risk Assessment Branch 6**~** 

## u 07

Health Effects Division (7509P)

and

Kelly Lowe, ExpoSAC Reviewer #1

# ~**~** Ana Rivera-Lupianez, ExpoSAC Reviewer #2 

## flvl-/v
Exposure Science Advisory Committee (ExpoSAC) I HED

Sheila Pip er, Senior Chemi st/Risk Assessor

Risk Assessment Branch VI

Health Effects Division (7509P)

Kaitlin Keller

, Chemical R eview Manager

Risk Management and Implementation Branch 3

Pesticide Re-Evaluation Di v i s ion (7508P)

As part of Registration Review

, the Pesticid e Re-evaluation Divi sion ( PRD ) of OPP reque sted

that the Hea l th E ffects Divi sion (HE D) conduct an occupational and residential exposure

Page I of41

### assessment, as needed

, to estimate th e risk to human health that w ill result from the currently

reg i stered uses oftrinexapac-ethyl.

It is HED policy to use the best avai lable data to assess exposure. Several sources of generic

data were used in this assessment as surrogate data in the absence of chemical-specific data, including: Pesticide Handlers Exposure Database Version 1.1 (PHED 1.1 ); 

### th e Agricultural

Handler Exposure Tas k Force (AHETF) database; the Outdoor Residential Expo sure Task Force (ORETF) database; the Agricultural Reentry Task Force (A RTF) database; the Residential SOPs (Turf/Lawn); and a chemical-specific turftransferable residue (TTR) study (MRID 45260201).

Some of these data are proprietary, and subject to the data protection provisions of the Federal
Insecticide, Fungicide, and Rodenticide Act (FIFRA).

Note: Thi s memorandum was reviewed by the Exposure Science Advisory Committee (ExpoSAC) on [7/18/13).

Page 2 of 41Page 3 of 41 

### Table of Contents

1.0 Executive Summary

................................ ................................ ................................ ............. 4

2.0 Risk Assessment Conclusions and Recommendations

................................ ........................ 6

2.1 Summary of Risk Estimates

................................ ................................ ............................. 6

2.2 Label Recommendations from Occupational/Residential Assessment

............................ 6

2.3 Data Deficiencies and Requirements

................................ ................................ ............... 6

3.0 Hazard Characterization

................................ ................................ ................................ ....... 7

4.0 Use Profile

................................ ................................ ................................ ......................... 10

5.0 Residential Exposure and Risk Estimates

................................ ................................ .......... 12

5.1 Residential Handler Exposure/Risk Estimates

................................ ............................... 13

5.2 Residential Post

- application Exposure/Risk Estimates

................................ .................. 17

5.3 Residential Risk Estimates for Use in Aggregate Assessment

................................ ...... 18

5.4 Spray Drift

................................ ................................ ................................ ...................... 20

5.5 Residential Bystander Post

- Application Inhalation Exposure

................................ ....... 20

6.0 Occupational Exposure and Risk Estimates

................................ ................................ ...... 21

6.1 Occupational Handler Exposure/Risk Estimates

................................ ............................ 21

6.2 Occupational Post

- application Exposure/Risk Estimates

................................ .............. 31

6.2.1 Occupational Post

- application Inhalation Exposure/Risk Estimates

...................... 31

6.2.2 Occupational Post

- application Dermal Exposure/Risk Estimates

.......................... 31 Appendix A. Summary of Occupational and Residential Non

- cancer Algorithms

..................... 35

1.2 Residential Handler Dose Calculations

................................ ................................ .......... 35Page 4 of 41



### 1.0 Executive Summary

Use Profile

Trinexapac

– ethyl is a cyclohexadione plant growth regulator that is marketed as an emulsifiable concentrate, wettable powder packed in water

- soluble bags, granule, and as a technical chemical used for formulation only. Trinexapac

- ethyl has multiple end

- us e products that are registered for use on turf areas such as sod farms, golf courses, sports fields, cemeteries and similar areas , and

on grasses grown for seed, sugarcane, and cereals (wheat, barley, oats, triticale)

. The label

required personal protecti ve equipment (PPE) for occupational applicators and handlers is a long

- sleeved shirt, long pants, shoes, and socks , chemical

- resistant gloves, and protective

eyewear

.

Hazard Profile

Since the previous human health risk assessment (D377921, S.Piper, 11/23/2011)

, no changes

have been made to the hazard characterization for t rinexapac

- ethyl. Endpoints of concern for the

incidental oral , inhalation, and dermal scenarios for children are not available from the trinexapac

- ethyl toxicity studies (see ratio nale in Section 3, Hazard Characterization below). For

short

- and intermediate

- term dermal and inhalation exposures for adults , the point of departure (POD) is from a n oral developmental study in rabbits . The LOAEL (Lowest Observed Adverse Effect Level) from this study was 360 mg/kg/day based on a decrease in the mean number of fetuses/litter and an increase in post

- implantation loss. The NOAEL (No Observed Adverse Effect Level) from this study was 60 m g/kg/day. A dermal absorption factor of 77.5 % was used for the exposure assessment based on information from a rat dermal penetration study (MRID 42238105)

. An oral study was selected for the inhalation route because there was no inhalation study of app ropriate duration, and based on a review by HASPOC

, a route

- specific inhalation toxicity study is not required at this time

. The level of concern (LOC) for occupational and non

occupational risk is for margins of expo sure (MOEs) less (<) than 100. A body weight of 69 kg was used for the inhalation and dermal assessment since the endpoints were from a developmental toxicity study with fetal effects. Since the dermal and inhalation scenarios are based on the same study, they can be combined when assessing occupational and residential

exposure. Trinexapac

- ethyl is classified as “Not likely to be carcinogenic to humans.”

Residential Exposure/Risk

HED determined that there is a potential for residential handler and post

- application exposure to trinexapac

- ethyl from the currently registered turf products

. An updated residential handler a nd
post

- application assessment was conducted because HED recently updated the Standard Operating Procedures for Residential Pesticide Exposure Assess ment ( http://www.epa.gov/opp00001/science/EPA

- OPP

- HED_Residential%20SOPS_Feb2012.pdf ) and body weights to be used in all human health assessments. The combined der mal plus

inhalation risk estimate s to residential handlers do not excee d HED’s LOC for all scenarios (i.e., MOEs ≥ 100) ; MOEs ranged from 240 to 21,000,000. The short

- term dermal residential post

application MOEs ranged from 450 to 61 ,000

, and therefore

, do n ot exceed HED’s LOC (MOE s ≥ 100) . Chemical

- speci fic TTR data are available for trinexapac

- ethyl and were used in thePage 5 of 41



### residential post

- application exposure assessment in conjunction with standard default assumptions

.

Occupational Exposure/Risk

HED d etermined that there is a potential for occupational handler and post

- application exposure to trinexapac

- ethyl from the currently registered products. The occupational handler assessment was completed assuming the maximum label application rate for each crop. The occupational handler exposure and risk estimates indicate that short

- and intermediate

- term dermal and

inhalation combined MOEs are not of con cern to HED (i.e., MOEs ≥ 100) w ith baseline attire and/or with the addition of gloves (as required on the labels ). Wi th baseline attire and/or gloves

, t he dermal plus inhalation MOEs range from 140 to 2,100,000

.

Chemical

- speci fic TTR data are available for trinexapac

- ethyl and were used in the occupational
post

- application exposure assessment to assess turf in conjunction with standard default assumptions to assess sugarcane, cereals (wheat, barley, oats, triticale), and grasses gr own for

seed

. The occupational post

- application dermal exposure and risk estimates indicate that short

and intermediate

- term MOEs are not of concern to HED (i.e., MOEs ≥ 100) on the day of application , except for hand

- harvesting sugarcane (MOE=87) whe re risk estimate s are of concern

until 2 days after application (MOE=110)

. The occupational post

- application MOEs on the day of application range from 87 to 43,000. Based on HED’s occupational post

- a pplication exposure

assessment, the restricted

- entry interval (REI) fo r hand

- harvesting sugarcane was estimated to be

2 days for short

- and intermediate

- term exposure. However, HED does not recommend that sugarcane REI’s be changed on the trinexapac

- ethyl labels at this time based on two main issues. One, almost all sugarcane harvesting in the United States is done mechanically. Two, the proposed trinexapac

- ethyl labels have a 28

- day pre

- harvest interval (PHI) for sugarcane

, so hand harvesting should not occur until after 28 days which is protective of the estimated REIs

. C urrent trinexapac

- ethyl labels have either no REI, 0 days, or a 4

- hour REI. The trinexapac

ethyl technical material has been classified in Toxicity Category III for acute dermal, oral, and primary eye irritation, and Category IV for acute inhalation and primary skin irritation. Therefore, the acute toxicity categories for this chemical require a 12 hour REI under 40 CFR 156.208 (c) (2) (iii). The Registration Division (RD) should ensure the proper REIs are put in place on the label s to reflect these requirements (D392798, M. Hawkins, 11/23/2011).

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

- cancer occupational post

- application inhalation exposure assessment was not performed for trinexapac

- ethyl at this time. If new policies or procedures are put into place, the Agency may revisit the need for a quantit ative occupational post

- application inhalation exposure assessment for trinexapac

- ethyl

.

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; the AHETF database; the Outdoor Residential Exposure Task Force (ORETF)

database ; the ARTF database ; the Res idential SOPs (Turf/Lawn ) ; and a chemical

- spe cific TTR study (MRID 45260201) 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 certainPage 6 of 41



### studies, the ethics review may have included review by the Human Studies Review Board. Descriptions of d ata sources, as well as guidance on their use, can be found at the Agency

website 1



### .

2.0 Risk Assessment Conclusions and Recommendations

2.1 Summary of Risk Estimates

There are no occupational/residential risk estimates of concern associated with the currently registered uses of trinexapac

- ethyl.

2.2 Label Re commendations from Occupational/Residential Assessment

The Registration Division (RD) should ensure the proper REIs are put in place considering the
post

- application assessment, the acute toxici ty of trinexapac and the criteria for 4

- hr REIs on the labels to reflect these requirements. (Hawkins, M., DP392798, 11/23/11).

2.3 Data Deficiencies and Requirements

Turf Transferable Residue (TTR): In accordance with the updated Part 158 data require ments (2007), a TTR study is required for all occupational (e.g., sod farms, golf courses, parks, and recreational areas) or residential turf uses. A TTR study (MRID 45260201) has been submitted

and reviewed for trinexapac

- ethyl. Therefore, there is not a data deficiency for this requirement.

Dislodgeable Foliar Residue (DFR): In accordance with the updated Part 158 data requirements (2007), one or more DF R stud ies are required when a pesticide has residential or occupational

uses t hat could result in post

- application dermal exposure. As part of the recent revision to the Health Effects Division’s 2012 Standard Operating Procedures for Residential Pesticide Exposure Assessment , HED analyzed a number of DFR studies and selected a new default value

for t he fraction of the application rate available to be dislodged after a foliar application (F AR 

### ).

This default value is 25 % and is based on an analysis of 19 DFR studies where the F AR 

### value ranged from 2% to 89%. This value is recommended for use in both r esidential and occupational
post

- application assessments. Of the analyzed DF R studies, the maximum F AR 

### 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 = 100) 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 ( Guidance for Requiring/Waiving Turf Transferrable Residue (TTR) and Dislodgeable Foliar Residue (DFR) Studies . 6/7/2012, Exposure Science Advisory Council ). A DFR study is required for trinexapac

- ethyl at this time since the re are dermal MOEs less than 4 times the

LOC based on default values for the fraction of application rate available for transfer after a foliar application.

1 http://www.epa.gov/pesticides/science/handler

- exposure

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

- app

- exposure

- data.htmlPage 7 of 41



### 3 .0 Hazard Characterization

Acute Toxicity

The acute toxicity for trinexapac

- ethyl technical formulation was classified as Toxicity Category III for acute oral, dermal, and eye irritation, and IV for acute inhalation and skin irritation

. Table

3. 1 presents a summary of the acute toxicity information for trinexapac

- ethyl

.

Table 3.1. Acute Toxicity Profile

- Trinexapac

- ethyl (97%)

Guideline

No. Study Type MRID Results Toxicity Category

870.1100 Acute oral [rat] 41563901 ♂ LD 50 = 4613 mg/kg ♀ LD 50 = 4212 mg/kg

Combined LD 50 = 4458 mg/kg III

870.1200 Acute dermal [rabbit] 41563910 LD 50 > 4000 mg/kg III

870.1300 Acute inhalation [rat] 41563912 LC 50 ≥ 5.3 mg/L IV

870.2400 Acute eye irritation [rabbit] 41563914 Minimal irritant; cleared by 72 hours III

870.2500 Acute dermal irritation [rabbit] 41563916 Slightly irritating; cleared by day 7 IV

870.2600 Skin sensitization [guinea pig] 41869522 Not a dermal sensitizer N/A



### Since the previous human health risk assessment (D377921, S.Piper, 11/23/2011)

, no changes have been made to the hazard characterization for trinexapac

- ethyl. A NOAEL of 60 mg/kg/day

was selected as the POD for short

- and intermediate

- term adult dermal and inhalation exposure.

The LOAEL is 360 mg/kg/day based on a decrease in the mean number of fetuses/litter and an

incre ase in post

- implantation loss. The chronic dog study was also considered since it has a similar LOAEL (357 mg/kg/day). The NOAELs established in these two studies, however, are 2

- fold different due to the dose

- spread in the two studies. Therefore, the higher NOAEL of 60 mg/kg/day from the rabbit developmental study (LOAEL 360 mg/kg/day) is protective of the effects observed (LOAEL 357 mg/kg/day) in the chronic dog study with NOAEL of 31.6 mg/kg/day. In addition, a lthough the 21

- day rabbit dermal study did not result in systemic

toxici ty at the limit dose and suggests a dermal assessment is not warranted, this study is performed only in adult animals, not pregnant animals. It is currently unknown if a dermal study with pregnant rabbits would result in an in utero effect similar to that observed in the rabbit developmental study. Therefore, the use of the rabbit developmental study for the short

- and

intermediate

- term adult dermal and inhalation scenarios is conservative and protective for these routes of exposure. Since the dermal and inhalation scenarios are based on the same study, they can be combined when assessing occupational and residential exposure.

The need for a subchronic inhalation study for trinexapac

- ethyl was discussed by the Hazard and Science Policy Co uncil (HASPOC) o n June 20, 2013 ( TXR 0056699 )

. The HASPOC concluded that based on a weight

- of

- evidence approach, considering all the available hazard and exposure information for trinexapac

- ethyl, a subchronic inhalation study is not needed at this time.

The short

- an d intermediate

- term dermal and inhalation endpoints selected for adults are only applicable to adults (females) because the endpoint is based on in utero effects. HED reviewed the full toxicological database for trinexapac

- ethyl in an attempt to select endpoints for thePage 8 of 41



### dermal and inhalation children scenarios; however, no appropriate endpoint was available for these scenarios based on the following reasons:

dermal irritation effects are mild after 21/28 days of exposure in the rabbit study, dermal irritation effects after a single exposure disappear after seven days, there are no systemic effects up to the limit dose in the dermal rabbit study, there are no adverse toxicological effects (at doses close to the limit dose of 1000 mg/kg/day) in the 2

- generation reproductive study in rats or in the chronic/carcinogenicity studies in rats and mice, there is no maternal toxicity in the developmental toxicity studies in both rats and rabbits, and there are no identifiable endpoints for the oral studies in the rat or rabbit.

An endpoint of concern for the incidental oral scenario is also not available from the available trinexapac

- ethyl toxicity studies and t he rationale for this conclusion is based on the following weight of evidence considerations:

the toxicity observed during the appropriate duration of concern (short/intermediate term) were observed only at high doses [LOAEL s = 900 mg/kg/day in the dog, 1000 mg/kg/day in the rat, and 1212 mg/kg/day in the reproduction study], the brain lesions observed in the chronic dog study are not appropriate for this scenario since the brain lesions were seen only at termination (i.e. after exposure for

1

- year) and toxicity observed after chronic exposure is not appropriate for application to the short/intermediate term scenarios,

the brain lesion s observed in the chronic study are not expected to occur after short term exposure due to the lack of similar lesion s or associated toxicity (i.e., clinical neurologic signs) in the 90

- day studies in rats or dogs,

the cause for concern for the brain lesions is low because of the minimal lesion severity, lack of associated changes (i.e., gliosis, myelin loss astrocyte hy pertrophy, neuronal necrosis etc), and the non

- specific nature of the lesions (i.e., focal vacuoles), the overall toxicity profile of this chemical clearly shows that toxicity is observed only at high doses (lowest LOAEL = 360 m g /k g /d ay in the chronic dog study), and

the in utero endpoint identified in the rabbit study is not appropriate for this population of concern (chi ldren) (D392798, M.Hawkins, 11/23/2011).

The Agency’s LOC for risks (i.e., target level for MOEs) is defined by uncertainty factors. The Agency applies a factor of 10X to account for interspecies extrapolation to humans from the animal test species and another factor of 10X to account for intra

- species sensitivity. HED previously concluded that the 10X FQPA Safety Factor for trinexapac

- ethyl can be reduced to 1X (D377921, S.Piper, 11/23/2011). The total uncertainty factor that has been applied to occupational and residential adult risk assessments is 100 for short

- and intermediate

- term dermal and inhalation exposures.Page 9 of 41



### Trinexapac

- ethy l is classified as “Not likely to be carcinogenic to humans.” This is based on the lack of carcinogenic potential noted in the available studies. There is no concern for mutagenicity and clastogenicity. Quantification of cancer risk is not required.

Absorption A dermal absorption factor of 77.5 % was used for the exposure assessment based on information from a rat dermal penetration study (MRID 42238105)

. The dermal absorption

factor was estimated based on the sum of 56.5% absorbed after 10 hours in the low dose group (0.01 mg/cm 2 

### ), in addition to 21% of applied dose that was associated with the application site. Since no inhalation absorption data are available, toxicity by the inhalation route is considered to be equivalent to the estimated toxicit y by the oral route of exposure.

Body Weight Since the dermal and inhalation PODs are based on developmental and/or fetal effects, the body weight appropriate for dermal and inhalation assessments is 69 kg.

Table 3. 2 presents the selected points of departure for trinexapac

- ethyl.

Table 3.2. Summary of Toxicological Doses and Endpoints for Trinexapac

- ethyl for use in Occupational/Residential Human Health Risk Assessments

. Exposure/

Scenario Point of Departure Uncerta inty/

FQPA Safety

Factors Level of Concern

for Risk

Assessment Study and Toxicological Effects

Acute Dietary (General Population, including Infants and Children) No appropriate endpoint for the general population including infants and children

Incidental Oral (Short and

Intermediate

- Term ) No appropriate endpoint was available for the incidental oral scenario.

Dermal & Inhalation (Children)

Short and

Intermediate

- Term (1

- 6 months) No appropriate endpoint was available for the children’s dermal and inhalation scenarios.

Dermal & Inhalation (Adults)

Short and

Intermediate

- Term (1

- 6 months) NOAEL= 60 mg/kg/day

Dermal absorption rate

= 77.5% of oral absorption

Inhalation absorption rate

= 100% of oral absorption UF A = 10x

UF H = 10x FQPA SF= 1x Residential LOC

for MOE = 100

Occupational

LOC for MOE =

100 Developmental rabbit study

MRID 41869524

LOAEL = 360 mg/kg, based on a

decrease in mean number of fetuses/litter and an increase in post

implantation loss

Cancer (oral, dermal, inhalation) Classification: “Not likely to be Carcinogenic to Humans”

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 = potential variation in sensitivity among members of the human population (intraspecies). FQPA SF = FQPA Safety Factor.Page 10 of 41



### 4 .0 Use Profile

Table 4. 1 provides a summary of the registered uses of trinexapac

- ethyl and represents the highest application r ate for each of the trinexapac

- ethyl formula tions. Several of the trinexapac

ethyl labels did not provide the pounds (lb) active ingredient (ai) per gallon of product; therefore, HED made assumptions in order to convert the rates to lb ai/A. A detailed s ummary of the registered products and application rates is provided in an attached Excel spreadsheet

.

Table 4. 1 Trinexapac

- ethyl Use Patterns and Formulations

Applic. Timing, Type, and Equip. Formulation

[EPA Reg. No.] Applic.

Rate (lb ai/A) Max. Seasonal

Applic. Rate (lb ai/A) Max.

Applic.

per

Season REI Use Directions and

Limitations

Turf

Back Pack, Hand Sprayers, Boom Sprayers, Hand Gun Sprayers 12% ai, EC

Primo Liquid
(EPA Reg. No.

100

- 729) 0.36 lb

ai/A (0.017 lb ai/gallon ; 0.000008

lb ai/ft 2 ) 0.36 lb ai/A Multiple 0 days Do not apply this product through any type of irrigation

system.

Back Pack, Hand Sprayers, Boom Sprayers, Spray

Gun 25.0 % ai,

Primo WSB

WP in Water Soluble Bag (EPA Reg. No.

100

- 752) 0.34 lb

ai/A (0.016 lb ai/gallon) 0.34 lb ai/A Multiple 0 days Do not apply this product through any type of irrigation

system.

Turf (Edging/Banding)

Spreader, Shaker

Can .01 %

- 1.0 % ai,

Lawn Primo F, Granule, (EPA Reg. No.

100

- 931) 0.88 lb

ai/A (0.00002

lb ai/ft 2 ) 0.88 lb ai/A Multiple 0 days Be sure the lawn has adequate fertility before using the product.

Backpack Sprayers, Hand Sprayers, Boom Sprayers, Spray

Guns 12% ai, EC

Primo Liquid
(EPA Reg. No.

100

- 729) 0.7 3 lb

ai/A 0.7 3 lb ai/A Multiple 0 days Do not apply this product through any type of irrigation

system.

Back Pack, Hand Sprayers, Boom Sprayers, Spray

Gun 25.0 % ai,

Primo WSB

, WP in Water Soluble Bag (EPA Reg. No.

100

- 752) 0.68 lb

ai/A 0.68 lb ai/A Multiple 0 days Do not apply this product through any type of irrigation

system.

Turf and Edging/Banding

Spreader, Shaker

Can 0.39% ai,

The Andersons

0.39% Trinexapac

0.88 lb

ai/A 0.88 lb ai/A Multiple 0 days Do not apply this product to grasses not listed on the label.Page 11 of 41 Table 4. 1 Trinexapac

- ethyl Use Patterns and Formulations

Applic. Timing, Type, and Equip. Formulation

[EPA Reg. No.] Applic.

Rate (lb ai/A) Max. Seasonal

Applic. Rate (lb ai/A) Max.

Applic.

per

Season REI Use Directions and

Limitations

ethyl + Fertilizer,

Granule,
(EPA Reg. No.

9198

- 246)

Sod Farm

Back Pack, Hand Sprayers, Boom Sprayers, Hand Gun Sprayers 12% ai, EC

Primo Liquid
(EPA Reg. No.

100

- 729) 0.36 lb

ai/A 0.36 lb ai/A Multiple 0 days Do not apply this product through any type of irrigation

system.

Back Pack, Hand Sprayers, Boom Sprayers, Spray

Gun , Aerial, Chemigation 25.0 % ai,

Primo WSB

, WP in Water Soluble Bag (EPA Reg. No.

100

- 752) 0.34 lb

ai/A 0.34 lb ai/A Multiple 0 days Do not apply this product through any type of irrigation

system.

Golf Course Fairways

Spreader, Shaker

Can 0.39% ai,

The Andersons

0.39% Trinexapac

ethyl + Fertilizer,

Granule,

(EPA Reg. No.

9198

- 246) 0.44 lb

ai/A 0.44 lb ai/A 0 days Do not apply this product to grasses not listed on the label.

Back Pack, Hand Sprayers, Boom Sprayers, Hand Gun Sprayers 12% ai, EC

Primo Liquid

(EPA Reg. No.

100

- 729) 0.18 lb

ai/A 0.18 lb ai/A Multiple 0 days Do not apply this product through any type of irrigation

system.

Back Pack, Hand Sprayers, Boom Sprayers, Spray

Gun 25.0 % ai,

Primo WSB

, WP in Water Soluble Bag (EPA Reg. No.

100

- 752) 0.17 lb

ai/A 0.17 lb ai/A Multiple 0 days Do not apply this product through any type of irrigation

system.

Golf Course Greens

Back Pack, Hand Sprayers, Boom Sprayers, Hand Gun Sprayers 11.3% ai,

Microemulsion

Concentrate

Primo Maxx
(EPA Reg. No.

100

- 937) 0.07 lb

ai/A 0.07 lb ai/A Multiple 0 days Do not apply this product through any type of irrigation

system.Page 12 of 41 Table 4. 1 Trinexapac

- ethyl Use Patterns and Formulations

Applic. Timing, Type, and Equip. Formulation

[EPA Reg. No.] Applic.

Rate (lb ai/A) Max. Seasonal

Applic. Rate (lb ai/A) Max.

Applic.

per

Season REI Use Directions and

Limitations

Spreader, Shaker

Can .01 %

- 1.0 % ai,

Lawn Primo F, Granule, (EPA Reg. No.

100

- 931) 0.07 lb

ai/A 0.07 lb ai/A Multiple 0 days Be sure the lawn has adequate fertility before using the product.

Back Pack, Hand Sprayers, Boom Sprayers, Spray

Gun 25.0 % ai,

Primo WSB

, WP in Water Soluble Bag (EPA Reg. No.

100

- 752) 0.05 lb

ai/A 0.05 lb ai/A Multiple 0 days Do not apply this product through any type of irrigation

system.

Grasses Grown For Seed

Aerial, Ground, Chemigation 12 %

Palisade EC, EC,
(EPA Reg. No.

100

- 949) 0.5 lb ai/A 0.5 lb ai/A 2 12 hours PHI = 35 days

Sugarcane

Aerial, Ground, Chemigation 12 %

Palisade EC, EC,
(EPA Reg. No.

100

- 949) 0.31 lb

ai/A 0.31 lb ai/A 2 12 hours PHI = 28 days

Cereals (Wheat, Barley, Oats, Triticale)

Aerial, Ground, Chemigation 12 %

Palisade EC, EC,
(EPA Reg. No.

100

- 949) 0.1 lb ai/A 0.11 lb ai/A 2 12 hours PHI = 45 days.



### 5 .0 Residential Exposure and Risk Estimates

This document addresses the potential residential exposure to trinexapac

- ethyl from the currently registered turf products. U pdated residential handler and post

- application assessments were

conducted be cause HED recently updated the Standard Operating Procedures for Residential Pesticide Exposure Assessment ( http://www.epa.gov/opp00001/science/EPA

- OPP

HED_Residential%20SOPS_Feb2012.pdf ) and body weights to be used in all human health

assessments. Based on the updated assessments, t he combined dermal plus inhalation risk

estimate s to residential handlers do not exceed HED’s level of concern for all scenarios (i.e., MOEs ≥ 100) . S hort

- term dermal post

- application risk estimate s were assessed for adults and children 11 to < 16 years old , and t he residential post

- a pplication MOEs ranged from 4 50 to

61 ,000 and ther efore do not exceed HED’s LOC (MOE s ≥ 100). The revision of residential exposures will impact the human healt h aggregate risk assessment for trinexapac

- ethyl

.Page 13 of 41



### 5 .1 Residential Handler 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 tasks related to applications and that exposures can vary depending on the specifics of each task. Residential handlers are addressed

somewhat differ ently by HED as homeowners are assumed to complete all elements of an application without use of any protective equipment.

The quantitative exposure/risk assessment developed for residential handlers is based on the following scenarios:

Mix ing/Loading/ Applying Liquid with Hose

- E nd Sprayer

, Mixing/Loadi ng/Applying Liquid with Manually

- P ressurized Handwand

, Mixing/Loading/Applying Liquid with Sprinkler Can

, Mixing/Loading/Applying Liquid with Backpack

, Mixing/Loading/Applying Wettable Powde rs in Water

- Soluble Packaging with Hose

- end Sprayer

, Mixing/Loading/Applying Wettable Powde rs in Water

- Soluble Packaging with Manually

- P ressurized Handwand

, Mixing/Loading/Applying Wettable Powde rs in Water

- Soluble Packaging with Backpack

, Applying Granule s with Push

- Type Rotary Spreader

, Applying Granules with Belly Grinder

, Applying Granules with Spoon

, Applying Granules with Cup

, Applying Granules with Hand Dispersal

, Applying Granules with Shaker Can

.

Residential Handler Exposure Data and Assumptions

A series of assumptions and exposure factors served as the basis for completing the residential handler risk assessments. Each assumption and factor is detailed below.

Application Rate : The maximum application rate s for the currently registered uses for

t rinexapac

- ethyl are listed in Table 4.1.

Unit Exposures and Area Treated or Amount Handled : Unit exposure values and estimates for

area treated or amount handled were taken from HED’s 2012 Residential SOPs 2



### .

Exposure Duration: Residential handler exposure is expected to be short

- term in duration.

Intermediate

- term exposures are not likely because of the intermittent nature of applications by

homeowners

.

Residential Handler Non

- Cancer Exposure and Risk Estimate Equations

2 Available: http://www.epa.g ov/pesticides/science/residential

- exposure

- sop.htmlPage 14 of 41



### The algorithms used to es timate exposure and dose for residential handlers can be found in Appendix A and/or the 2012 Residential SOPs 3



### .

Combining Exposures/Risk Estimate s:

Dermal and inhalation risk estimate s were combined in this assessment, since the toxicological

effects for these exposure routes were similar. Dermal and inhalation risk estimate s were combined using the following formula:

Total MOE = Point of Departure (mg/kg/day) ÷ Combined D ermal + I nhalation dose (mg/kg/day)



### Summary of Residential Handler Non

- Cancer Exposure and Risk Estimates

The combined dermal and inhalation MOEs for residential handlers ranged from 240 to 21,000,000. The MOEs for all of the scenarios excee d the LOC of 100 which indicate that the residential handler exposure risk estimate s are not of concern. The residential handler exposures

and MOEs are calculated as detailed in Table 5.1 .1.

3 Available: http://www.epa.gov/pesticides/science/residential

- exposure

- sop.htmlPage 15 of 41

Table 5.1.1. Residential Handler Non

- cancer Expo sure a nd Risk Estimates for Trinexapac

- ethyl

.

Exposure Scenario Level of

Concern Dermal Unit

Exposure (m g/lb ai) Inhalation

Unit Exposure (m g/lb ai) Maximum

Application

Rate 1 Area Treated or

Amount

Handled Daily 2 Dermal Inhalation Total

Dose (mg/kg/day) 3 MOE 4 Dose (mg/kg/day) 5 MOE 6 MOE 7

Mixer/ L oader/Applicator

Lawns/Turf L iquid with

Hose

- End Sprayer 100 13.4 0.022 0.36 lb ai/A 0.5 acres 0.027 2,200 0.000058 1,000,000 2,200

Lawns/Turf Liquid with Manually

- Pressurized

Handwand 100 63 0.018 0.017 lb ai/gallon 5 gallons 0.06 1,000 0.000022 2,700,000 1,000

Lawns/Turf Liquid with Sprinkler Can 100 13.4 0.022 0.000008 lb

ai/ft 2 1,000 ft 2 0.0012 50,000 0.0000026 24,000,000 50,000

Lawns/Turf Liquid with Backpack 100 130 0.14 0.017 lb ai/gallon 5 gallons 0.12 480 0.00017 350,000 480

Lawns/Turf Liquid with Backpack (Edging/Banding) 100 130 0.14 0.034 lb ai/gallon 5 gallons 0.2482 240 0.00034 170,000 240

Lawns/Turf Wettable

Powders in Water

Soluble Packaging with

Hose

- End Sprayer 100 6.26 0.034 0.3 4 lb ai/A 0.5 acres 0.01 2 5,0 00 0.0000 84 720 ,000 5,0 00

Lawns/Turf Wettable

Powders in Water

Soluble Packaging with Manually

- Pressurized

Handwand 100 63 0.018 0.016 lb ai/gallon 5 gallons 0.057 1,100 0.000021 2,900,000 1,100

Lawns/Turf Wettable

Powders in Water

Soluble Packaging with Backpack 100 63 0.018 0.016 lb ai/gallon 5 gallons 0.057 1,100 0.000021 2,900,000 1,100

Lawns/Turf Granule

with Push

- Type Rotary Spreader 100 0.81 0.0026 0.88 lb ai/A 0.5 acres 0.004 15,000 0.000017 3,600,000 15,000

Lawns/Turf Granule with Belly Grinder 100 360 0.039 0.00002 lb

ai/ft 2 1,200 ft 2 0.097 620 0.000014 4,400,000 620

Lawns/Turf Granule with Spoon 100 6.2 0.087 0.00002 lb

ai/ft 2 100 ft 2 0.00014 430,000 0.0000025 24,000,000 420,000

Lawns/Turf Granule 100 0.11 0.013 0.00002 lb 100 ft 2 0.0000025 24,000,000 0.00000038 160,000,000 21,000,000Page 16 of 41

Table 5.1.1. Residential Handler Non

- cancer Expo sure a nd Risk Estimates for Trinexapac

- ethyl

.

Exposure Scenario Level of

Concern Dermal Unit

Exposure (m g/lb ai) Inhalation

Unit Exposure (m g/lb ai) Maximum

Application

Rate 1 Area Treated or

Amount

Handled Daily 2 Dermal Inhalation Total

Dose (mg/kg/day) 3 MOE 4 Dose (mg/kg/day) 5 MOE 6 MOE 7

with Cup ai/ft 2

Lawns/Turf Granule with Hand Dispersal 100 160 0.38 0.00002 lb

ai/ft 2 100 ft 2 0.0036 17,000 0.000011 5,400,000 17,000

Lawns/Turf Granule

with Shaker Can 100 0.11 0.013 0.00002 lb

ai/ft 2 100 ft 2 0.0000025 24

, 000,000 0.00000038 160,000,000 21,000,000

1 Based on currently registered trinexapac

- ethyl label s

. 2 Based on HED’s 2012 Residential SOPs ( http://www.epa.gov/pesticides/science/residential

- exposure

- sop.html ).

3 Dermal Dose = Dermal Unit Exposure (mg/lb ai) × Application Rate (lb ai/acre or gal) × Area Treated or Amount Handled (A /day or gallons/day) × Dermal Absorption Factor ( 77.5 %) ÷ Body Weight ( 69 kg).

4 Dermal MOE = Dermal NOAEL ( 60 mg/kg/day) ÷ Dermal Dose (mg/kg/day).

5 Inhalation Dose = Inhalation Unit Exposure (mg/lb ai) × Application Rat e (lb ai/acre or gal) × Area Treated or Amount Handled (A /day or gallons/day) ÷ B ody W eight ( 69 kg).

6 Inhalation MOE = Inhalation NOAEL ( 60 mg/kg/day) ÷ Inhalation Dose (mg/kg/day).

7 Total MOE = NOAEL ( 60 mg/kg/day) ÷ (Dermal Dose + Inhalat ion Dose)Page 17 of 41



### 5

. 2 Residential Post

- application Exposure/Risk Estimates

There is the potential for post

- application exposure for individuals exposed as a result of being in

an environment that h as been previously treated with trinexapac

- ethyl. Although there is the potential for dermal and oral post

- application exposure to children, no dermal or oral exposure endpoint s were selected (see rationale in Section 3, Hazard Characterization above). Therefore, a quantitative dermal and oral post

- appli cation assessment for children was not conducted.

The quantitative exposure/risk assessment for residential post

- application exposures is based on the following scenarios:

Adults (dermal) performing high contact yard work on treated turf,

Adults (der mal) mowing treated turf, and

Adults (dermal) playing golf on treated turf

. Child 11 to < 16 years old (dermal) playing golf on treated turf Child 11 to < 16 years old (dermal) mowing treated turf

Residential Post

- application Exposure Data and Assumptions A series of assumptions and exposure factors served as the basis for completing the residential
post

- application risk assessment . Each assumption and factor is detailed in the 2012 Residential

SOPs 4 

### . In addition, chemical

- specific residue data from a TT R study (MRID No. 45260201) was used to estimate day zero residues for the dermal post

- application exposure assessments from use of liquid formulations

. In the TTR study (MRID No. 45260201), the test site s consisted of plots located in Georgia, California , and Indiana treated with a microemulsion

formulation . The Georgia site resulted in the highest average p redicted day 0 residue value of

0 .0 31 ug/cm 2 

### but this was based on the edging/banding application rate of 0.69 lb ai/ A

. Therefore, HED adjusted the residue value of 0.0 31 ug/cm 2 

### for the maximum broadcast turf rate s of 0.36 and 0.88 lb ai/A for liquid and granular formulations, respectively, and the maximum golf course rate s of 0.18 and 0.44 lb ai/A, for liquid and granul ar formulations, respectively,

which resulted in predicted day 0 residue values of 0.0 16 and 0.0 0 8 ug/cm 2 

### for the liquid

formulations and 0.040 and 0.020 ug/cm 2 

### for the granular formulations (See Appendix B for more details). Chemical

- specific residue data from the TTR study (MRID No. 45260201) was used to assess residential post

- application risk estimates from exposure to the liquid and granular

formulations

. The exposure potential to a gr anular formulation is expected to be less than that from a liquid formulation; therefore, the assessment of dermal exposure from the granula r formulation should be considered a conservative assessment.

Residential Post

- application Non

- Cancer Exposure and Risk Equations The algorithms used to estimate residential post

- application exposure and dose can be found in Appendix A and/or the 2012 Residential SOPs 5



### .

Summary of Residential Post

- application Non

- Cancer Exposure and Risk Estimates

4 Available: http://www.epa.gov/pesticides/science/residential

- exposure

- sop.html

5 Available: http://www.epa.gov/pesticides/science/r esidential

- exposure

- sop.htmlPage 18 of 41



### The residential post

- application dermal MOEs ranged from 450 to 61 ,000 and therefore do not exceed HED’s LOC (MOE s ≥ 100). A summary of the residential post

- application exposures/risk estimates is presented in Table 5.2.1.

Table 5.2.1 Residential Post

- application Non

- Canc er Exposure and Risk Estimates for Trinexapac

- ethyl.

Lifestage Post

- application Exposure

Scenario TTR (ug/cm 2 ) 1 Dose

(mg/kg/day) 2 MOEs 3

Use Site Activity / Route

of Exposure Sprays

Chil d 11 to < 16 years old Turf Golf Course (Dermal) 0.00 8 0.002 31,000

Child 11 to 16 years old Turf Mowing (Dermal) 0.016 0.001 61,000

Adult Turf High Contact

Lawn Activities (Dermal) 0.0 1 6 0. 0 49 1,200

Mowing (Dermal) 0.0 1 6 0.00 1 61 ,000

Golf Course (Dermal) 0.0 0 8 0.00 2 31,000

Granular Formulation

Child 11 to < 16 years old Turf Golf Course (Dermal) 0.0 20 0.005 13,000

Child 11 to 16 years old Turf Mowing (Dermal) 0.040 0.002 25,000

Adult Turf High Contact

Lawn Activities (Dermal) 0. 0 40 0. 135 450

Mowing (Dermal) 0. 0 40 0.00 2 24 ,000

Golf Course (Dermal) 0. 0 20 0.00 5 13 ,000

1 TTR= chemical

- specific data from MRID 45260201 for the Georgia site adjusted for differences in application rates (0.36 lb ai/A for residential turf and 0.18 lb ai/A for golf courses)

. See Appendix B for more information regarding the available data.

2 Dose (mg/kg/day) equations: See Appendix A and Appendix B for input s

. 3 MOE = POD ( 60 mg/kg/day) ÷ Dose (mg/kg/day).



### 5

. 3 Residential Risk Estimates for Use in Aggregate Assessment

Table 5.3 .1 reflects the residential risk estimates that are recommended for use in the aggregate

as sessment for trinexapac

- ethyl.

The recommended residential exposure for use in the adult aggregate assessment reflects

dermal and inhalation exposure from handler e xposure to sprays that are applied on turf with backpack sprayers (edging/banding)

, which resulted in a MOE of 240

. The recommended residential exposure use in the child aggregate assessment reflect s dermal exposure from mowing turf that has been treate d with a granular formulation

, which resulted in a MOE of 13,000.Page 19 of 41

Table 5

. 3 .1. Recommendations for the Residenti al Exposures for the Trinexapac

- ethyl Aggregate Assessment

. 1

Lifestage Residential Handler Residential Post

- application

Dose (mg/kg/day) 2 MOE 3 Dose (mg/kg/day) 4 MOE 5

Dermal Inhalation Total Dermal Inhalation Total Dermal Inhalation Oral Total Dermal Inhalation Oral Total

Short

- Term

Adult Female 0. 2482 0.000 34 0. 249 240 170 ,000 240 0. 135 N/A N/A 0. 135 450 N/A N/A 450

C hild 11 to 16 years old N/A N/A N/A N/A N/A N/A 0.005 N/A N/A 0.005 13,000 N/A N/A 13,000

1 Bolded risk estimates should contribute to the residential exposure portion of the aggregate assessment.

2 Residential Handler Dose = the highest handler dose for each applicable lifestage of all scenarios assessed from Table 5.1.1

. Total = dermal + inh alation.

3 Residential Handler MOE = the MOEs associated with the highest doses identified in Table 5.1.1. Total = 1 ÷ (1/Dermal MOE) + (1/Inhalation MOE).

4 Residential Post

- application Dose = the highest post

- application dose for each applicable lifesta ge of all scenarios assessed from Table 5.2.1. Total = dermal + inhalation + incidental oral, where applicable.

5 Residential Post

- application MOE = the MOEs associated with the highest doses identified in Table 5.2.1. Total = 1 ÷ (1/Dermal MOE) + (1/Inhalation MOE) + (1/Incidental oral MOE).Page 20 of 41



### 5

. 4 Spray Drift

Off

- target movement of pesticides can occur via many types of pathways and it is governed by a variety of factors. Sprays that are released and do not depo sit in the application area end up off

target and can lead to exposures to those it may directly contact. They can also deposit on surfaces where contact with residues can eventually lead to indirect exposures ( e.g. , children playing on lawns where residue s have deposited next to treated fields). The potential risk estimates from these residues can be calculated using drift modeling coupled with methods employed for residential risk assessments for turf products.

The approach to be used for quantitatively incorporating spray drift into risk assessment is based on a premise of compliant applications which, by definition, should not result in direct exposures to individuals because of existing label language and other regulatory requirements intended to

preve nt them. 6 

### Direct exposures would include inhalation of the spray plume or being sprayed directly. Rather, the exposures addressed here are thought to occur indirectly through contact with impacted areas, such as residential lawns, when compliant applicat ions are conducted. Given this premise, exposures for children (1 to 2 years old) and adults who have contact with turf where residues are assumed to have deposited via spray drift thus resulting in an indirect exposure are the focus of this analysis anal ogous to how exposures to turf products are

considered in risk assessment.

Several trinexapac

- ethyl products have existing labels for use on turf, thus it was considered whether the risk assessment for that use may be considered protective of any type o f exposure that would be associated with spray drift. It should be noted that t he registered residential uses on turf result in exposure greater than potential exposure from spray drift; therefore, no new

residential assessment for spray drift needs to be completed

. If the maximum application rate on crops adjusted by the amount of drift expected is less than or equal to existing turf application rates, the existing turf assessment is considered protective of spray drift exposure. The proposed

maximum si ngle ap plication rate of trinexapac

- ethyl on grasses grown for seed is 0.5 lb ai /acre. According to the Tier 1 output from the groundboom spray profile of the AgDrift mode l

, trinexapac

- ethyl passed the spray drift screening because the maximum applicatio n rate to a crop target site (grasses grown for seed) multiplied by the adjustment factor for drift of 0.26 is less than the direct spray residential turf application rate (0.36 lb ai/A) 7



### . The turf post

- application

MOEs have been previously assessed and are based on the revised SOPs for Residential Exposure Assessment (see above in Section 5.2).

5

. 5 Residential Bystander Post

- Application Inhalation Exposure

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

- application inhalation exposure assessment was not performed for trinexapac

- ethyl at this time primarily because of the low acute inhalation toxicity (Toxicity Category III and IV)

. However, volatilization of pesticides may be a source of post

- application inhalation exposure to individuals nearby pesticide

6 

### This approach is consistent with the requirements of the EPA’s Worker Protection Standard which, when included on all labels, pre cludes direct exposure pathways

. 7 0.5 lb ai/A x 0.26 = 0.13 lb ai/APage 21 of 41



### 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 200 9, and received the SAP’s final report on March 2, 2010 8



### . 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

- applicatio n inhalation exposure into the Agency's risk assessments. If new policies or procedures are developed, the Agency may revisit the need for a quantitative post

- application inhalation exposure assessment for trinexapac

- ethyl

.

6 .0 Occupational Exposure and Risk Estimates

6 .1 Occupational Handler 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 applic ations and exposures can vary depending on the specifics of each task. 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 exposu re is expected from the currently

reg istered uses. The quantitative exposure/risk assessment developed for occupational handlers is based on the following scenarios: Mixing/Loading Granules for Tractor Drawn Spreader Applications Mixing/Loading Liquids for Aerial A pplications Mixing/Loading Liquids for C hemigation Mixing/Loading L iquid s for G roundboom A pplications Mixing/Loading Wettable Powders in Water Soluble Bags for Aerial A pplications Mixing/Loading Wettable Powders in Water Soluble B ags for C hemigation Mixing/Loading Wettable P owders in Water Soluble Bags for Groundboom A pplications Applying Sprays for Aerial A pplications Applying Sprays for G roundboom Applications Applying G ranu les for Tractor Drawn Spreader A pplications Flagging (S prays ) during Aerial A pplications Mixing/Loading/A ppl yin g Liquids for B ackpack A pplications Mixing/Loading/A pply ing L iquids f or Manually

- Pressurized Handwand Applications Mixing/Loading/Applying L iquids for Mechanically

- Pressurized Handgun Applications Mixing/Loading/Applying Wettable Powders in Water Solubl e B ags for Backpack

A pplications Mixing/Loading/A pplying Wettable Powders in W ater Soluble Bags for Manually

Pressurized Handwand A pplications Mixing/Loading/Applying Wettable Powders in Water Soluble Bags for Mechanically

Pressurized Handgun Applications

8 Available: http://www.epa.gov/scipoly/SAP/meetings/2009/120109meeting.htmlPage 22 of 41



### Loading/Applying Granules for Belly Grinder A pplications

L oading/applying granules for Rotary Spreader A pplications

Occupational Handler Exposure Data and Assumptions

A series of assumptions and exposure factors served as the basis for completing the occupational handler risk assessments. Each assumption and factor is detailed below on an individual basis.

Application Rate : The maximum application rate s for the currently registered uses of trinexapac

ethyl, as presented in Table 4

. 1

, w ere used to es timate occupational ha ndler exposure

.

Unit Exposures: It is the policy of HED to use the best available data to assess handler exposure. Sources of generic handler data, used as surrogate data in the absence of chemical

- specific data, include PHED 1.1, the AHETF database, the Outdoor Residential Exposure Task Force (ORETF) database, or other registrant

- submitted occupational exposure studies. Some of these data are proprietary (e.g., AHETF data), and subject to the data protection provisions of FIFRA. The standard values recommended for use in predicting handler exposure that are used in this assessment, known as “unit exposures”, are outlined in the “Occupational Pesticide Handler Unit Exposure Surrogate Reference Table 9 

### ”, which, along with additional information on HED policy on use of surrogate data, including descriptions of the various sources, can be found at the Agency website 10



### .

Area Treated or Amount Handled :

T ractor

- drawn spreader application s for golf course (fairways, tees, greens): 40 a cres
T ractor

- drawn spreader application s for golf course (tees and greens only) : 5 acres

A erial application s for typical crops: 350 acres Aerial applications for high acre crops: 120 0 acres

C hemigation application s for typical and high acre crops: 350 acres
G roundboom application s for golf course (tees and greens only) : 5 acres

G roundboom application s for golf course (fairways, tees, greens) : 40 acres

G roundboom application s for typical crop s : 80 acres Groundboom applications for high acre crops : 200 acres Flagging for aerial applications: 350 acres Backpack applications: 40 gallons Manually

- pressurized handgun: 40 gallons Mechanically

- pressurized handgun: 5 acres Belly grinder applications: 1 acre Rotary spreader application: 5 acres

Exposure Duration : HED classifies exposures from 1 to 30 days as short

- term and exposures 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 triggering the use of the

9 Available: http://www.epa.gov/opp00001/science/handler

- exposure

- table.pdf

10 Available: http://www.epa.gov/pesticides/science/handler

- exposure

- data.htmlPage 23 of 41



### 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 la rge agribusiness and/or commercial applicators who may apply a product over a period of weeks (e.g., completing multiple applications for multiple clients within a region).

For trinexapac

- ethyl , based on the currently registered use s
, short

- and interme diate

- term exposure is expected for handlers. The short

- and intermediate

- term endpoints and PODs are the same for each exposure route, therefore only short

- term handler exposures were estimated, and are considered protective for intermediate

- term exposur e and risk. Long

- term exposures are not expected.

Mitigation/Personal Protective Equipment: Estimates of dermal and inhalation exposure were calculated for various levels of personal protective equipment (PPE). Results are presented for “baseline,” def

ined as a single layer of clothing consisting of a long sleeved shirt, long pants, shoes plus socks, no protective gloves, and no respirator, as well as baseline with various levels

of PPE as necessary (e.g., gloves, respirator, etc ). The trinexapac

- ethyl product labels direct mixers, loaders, applicators and other handlers to wear long

- sleeved shirt, long pants, shoes, and

socks , chemical

- resistant gloves, and protective eyewear.

Occupational Handler Non

- Cancer Exposure and Risk Estimate Equations The algorithms used to estimate non

- cancer exposure and dose for occupational handlers can be found in Appendix A

.

Combining Exposures/ Risk Estimates :

Dermal and inhalation risk estimates 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/kg/day) ÷ Combined dermal + inhalation dose (mg/kg/day)



### Summary of Occupational Handler Non

- Cance r Exposure and Risk Estimates

The short

- and intermediate

- term risk estimates for occupational handlers are included in Table

6.1.1. All dermal and inhalation occupational handler scenarios are above HED’s LOC (MOEs

≥ 100) with baseline attire and/or gloves and engineering control (i.e., enclosed co ckpits) for aerial applications

. With baseline attire and/or gloves, the dermal plus inhalation MOEs range from 140 to 2,100,000.

The Agency matches quantitative occupatio nal 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 to the 2012 National Agricultural Aviation Association (NAAA) survey of their membership, the use of GPS for swath guidance 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 recentPage 24 of 41



### (2012) NAAA survey. The Agency will continue to monitor all available information sources to best assess and characterize the exposure potential for human flagg ers in agricultural aerial applications.

HED has no data to assess exposures to pilots using open cockpits. The only data available is for exposure to pilots in enclosed cockpits. Therefore, risks to pilots are assessed using the engineering control (e nclosed cockpits) and baseline attire (long

- sleeve shirt, long pants, shoes, and socks); per the Agency’s Worker Protection Standard stipulations for engineering controls, pilots are not required to wear protective gloves for the duration of the applicatio n . With this level of protection, there are no risk estimates of concern for applicators.Page 25 of 41

Table 6.1.1. Occupational Handler Non

- Cancer Exposure and Risk Estimates for Trinexapac

- ethyl

.

Exposure Scenario Crop or Target Dermal Unit Exposure ( μ g/lb ai) 1 Inhalation Unit

Exposure ( μ g/lb ai) 1 Maximum

Application

Rate 2 Area

Treated or

Amount

Handled Daily 3 Dermal Inhalation Total

Mitigation Level Mitigation Level Dose (mg/kg/day) 4 MOE 5 Dose (mg/kg/day) 6 MOE 7 MOE 8

M ixing/Loading Granules

Tractor

- Drawn Spreader Application Golf Course

(Fairways, Tees, Greens) 8.4 1.7 0.44 40 0.00166 36,000 0.000433 140,000 29

, 000

Golf Course (Tees and Greens Only) 8.4 1.7 0.44 5 0.000208 290,000 0.0000542 1,100,000 230

, 000

Mixing/Loading Liquids

Aerial Application Sod 220 0.219 0.36 350 0.314 190 0.000404 150,000 190

Grasses G rown For Seed 220 0.219 0.5 350 0.432 140 0.000555 110,000 140

Sugarcane 220 0.219 0.31 350 0.268 220 0.000345 170,000 220

Cereals ( Wheat, Barley, Oats, Triticale) 220 0.219 0.11 1200 0.326 180 0.000419 140,000 180

Chemigatio n Application Sod 220 0.219 0.36 350 0.314 190 0.000404 150,000 190

Grasses Grown

For Seed 220 0.219 0.5 350 0.432 140 0.000555 110,000 140

Sugarcane 220 0.219 0.31 350 0.268 220 0.000345 170,000 220

Cereals (Wheat, Barley, Oats, Triticale) 220 0.219 0.11 350 0.0951 630 0.000122 490,000 630

Groundboom Application Golf Course (Tees and Greens Only) 220 0.219 0.07 5 0.000865 69,000 0.00000111 54,000,000 69,000

Golf Cour se (Fairways, Tees, Greens) 220 0.219 0.18 40 0.018 3,300 0.000023 2,600,000 3,300

Sod 220 0.219 0.36 80 0.072 830 0.0000925 650,000 830

Grasses Grown

For Seed 220 0.219 0.5 80 0.0988 610 0.000127 470,000 610Page 26 of 41

Table 6.1.1. Occupational Handler Non

- Cancer Exposure and Risk Estimates for Trinexapac

- ethyl

.

Exposure Scenario Crop or Target Dermal Unit Exposure ( μ g/lb ai) 1 Inhalation Unit

Exposure ( μ g/lb ai) 1 Maximum

Application

Rate 2 Area

Treated or

Amount

Handled Daily 3 Dermal Inhalation Total

Mitigation Level Mitigation Level Dose (mg/kg/day) 4 MOE 5 Dose (mg/kg/day) 6 MOE 7 MOE 8

Sugarcane 220 0.219 0.31 80 0.0613 980 0.0000787 760,000 980

Cereals ( Wheat, Barley, Oats, Triticale) 220 0.219 0.11 200 0.0544 1,100 0.0000699 860,000 1,100

Mixing/Loading Wettable Powders In Water Soluble Packaging

Aerial Application Sod 9.8 (EC) 0.24 (EC) 0.34 350 0.0131 (EC) 4,600 (EC) 0.000414 (EC) 140,000 (EC) 4,500 (EC)

Chemigation Application Sod 9.8 (EC) 0.24 (EC) 0.34 350 0.0131 (EC) 4,600 (EC) 0.000414 (EC) 140,000 (EC) 4,500 (EC)

Groundboom Golf Course

(Tees and Greens Only) 9.8 (EC) 0.24 (EC) 0.05 5 0.0000275 (EC) 2,200,000

(EC) 0.00000087

(EC) 69,000,000

(EC) 2,100,000

(EC)

Groundboom Golf Course

(Fairways, Tees, Greens) 9.8 (EC) 0.24 (EC) 0.17 40 0.000748 (EC) 80,000

(EC) 0.0000236

(EC) 2,500,000

(EC) 78,000

(EC)

Groundboom Sod 9.8 (EC) 0.24 (EC) 0.34 80 0.003 (EC) 20,000 (EC) 0.0000946

(EC) 630,000

(EC) 19,000

(EC)
Appling Sprays

Aerial Application Sod 2.08 (EC) 0.0049 (EC) 0.36 350 0.00298 (EC) 20,000

(EC) 0.00000904

(EC) 6,600,000

(EC) 20,000

(EC)

Grasses Grown

For Seed 2.08 (EC) 0.0049 (EC) 0.5 350 0.00409 (EC) 15,000

(EC) 0.0000124(EC) 4,800,000 (EC) 15,000

(EC)

Sugarcane 2.08 (EC) 0.0049 (EC) 0.31 350 0.00254 (EC) 24,000

(EC) 0.00000771

(EC) 7,800,000(EC) 24,000 (EC)

Cereals (Wheat, Barley, Oats, Triticale) 2.08 (EC) 0.0049 (EC) 0.11 1200 0.00309 (EC) 19,000

(EC) 0.00000938

(EC) 6,400,000

(EC) 19,000

(EC)

Groundboom Application Golf Course (Tees and Greens Only) 78.6 0.34 0.07 5 0.000309 190,000 0.00000172 35,000,000 190,000

Golf Course (Fairways, Tees, Greens) 78.6 0.34 0.18 40 0.00642 9,300 0.0000359 1,700,000 9,200Page 27 of 41

Table 6.1.1. Occupational Handler Non

- Cancer Exposure and Risk Estimates for Trinexapac

- ethyl

.

Exposure Scenario Crop or Target Dermal Unit Exposure ( μ g/lb ai) 1 Inhalation Unit

Exposure ( μ g/lb ai) 1 Maximum

Application

Rate 2 Area

Treated or

Amount

Handled Daily 3 Dermal Inhalation Total

Mitigation Level Mitigation Level Dose (mg/kg/day) 4 MOE 5 Dose (mg/kg/day) 6 MOE 7 MOE 8

Sod 78.6 0.34 0.36 80 0.0257 2,300 0.000143 420,000 2,300

Grasses Grown

For Seed 78.6 0.34 0.5 80 0.0353 1,700 0.000197 300,000 1,700

Sugarcane 78.6 0.34 0.31 80 0.0219 2,700 0.000122 490,000 2,700

Cereals ( Wheat, Barley, Oats, Triticale) 78.6 0.34 0.11 200 0.0194 3,100 0.000108 560,000 3,100

Appl y ing Granules

Tractor

- Drawn Spreader Application Golf Course

(Fairways, Tees, Greens) 9.9 1.2 0.44 40 0.00195 31,000 0.000306 200,000 27,000

Tractor

- Drawn Spreader Application Golf Course

(Tees and Greens Only) 9.9 1.2 0.44 5 0.000245 240,000 0.0000383 1,600,000 210,000

Flagger

Aerial Application Sod 11 0.35 0.36 350 0.0157 3

, 800 0.000646 93,000 3

, 700

Grasses Grown

For Seed 11 0.35 0.5 350 0.0217 2

, 800 0.000888 68,000 2

, 700

Sugarcane 11 0.35 0.31 350 0.0134 4

, 500 0.000551 110,000 4

, 300

Cereals ( Wheat, Barley, Oats, Triticale) 11 0.35 0.11 350 0.00476 13

, 000 0.000196 310,000 12

, 000

Mixing/Loa ding/Appling Liquids

Backpack Application Landscaping Turf (Lawns, Athletic Fields, Parks, etc.) 8260 2.58 0.017 40 0.0631 950 0.0000254 2,400,000 950

Manually

– Pressurized

Handwand Landscaping

Turf (Lawns, Athletic Fields, Parks, etc.) 100000

(baseline) 30 0.017 40 0.764 (baseline) 79

(baseline) 0.000296 200,000 79 (baseline)

430 (with gloves) 0.00328 (with gloves) 18,000

(with 1 7 ,000 (withPage 28 of 41

Table 6.1.1. Occupational Handler Non

- Cancer Exposure and Risk Estimates for Trinexapac

- ethyl

.

Exposure Scenario Crop or Target Dermal Unit Exposure ( μ g/lb ai) 1 Inhalation Unit

Exposure ( μ g/lb ai) 1 Maximum

Application

Rate 2 Area

Treated or

Amount

Handled Daily 3 Dermal Inhalation Total

Mitigation Level Mitigation Level Dose (mg/kg/day) 4 MOE 5 Dose (mg/kg/day) 6 MOE 7 MOE 8

gloves) gloves)

Ba ckpack Application Edging/Banding for Landscaping Turf (Lawns, Athletic Fields, Parks, etc.) 8260 2.58 0.03 40 0.11 540 0.0000449 1,300,000 540

Manually

– Pressurized

Handwand Edging/Banding

for Landscaping Turf (Lawns, Athletic Fields, Parks, etc.) 100000

(baseline)

30 0.03 40 1.35 (baseline) 44

(baseline)

0.000522 110,000 44 (baseline)

430 (with gloves) 0.0058 (with gloves) 10,000

(with gloves) 9,200 (with gloves)

Me chanically

- Pressurized Handgun Golf Course

(Tees and Greens Only) 1140 1.9 0.07 5 0.00448 13,000 0.00000964 6,200,000 13,000

Mechanically

- Pressurized Handgun Golf Course

(Fairways, Tees, Greens) 1140 1.9 0.18 5 0.0117 5,100 0.0000251 2,400,000 5,100

Mechanically

- Pressurized Handgun Landscaping

Turf (Lawns, Athletic Fields, Parks, etc.) 1140 1.9 0.36 5 0.0233 2,600 0.0000501 1,200,000 2,600

Mechanically

- Pressurized Handgun Edging/Banding

for Landscaping Turf (Lawns, Athletic Fields, Parks, etc.) 1140 1.9 0.73 5 0.0467 1,300 0.000101 590,000 1,300

Mixing/Loading/Applying Wettable Powders In Water Soluble Packaging

Backpack Application Landscaping Turf (Lawns, Athletic Fields, Parks, etc.) 8260 2.58 0.016 40 0.0 594 1,000 0.0000239 2,500,000 1,000

Manually

– Pressurized

Handwand Landscaping

Turf (Lawns, Athletic Fields, 100000

(baseline) 30 0.016 40 0.7 19 (baseline) 83

(baseline) 0.000278 220,000 83 (baseline)

430 0.00309 19,000 17,000Page 29 of 41

Table 6.1.1. Occupational Handler Non

- Cancer Exposure and Risk Estimates for Trinexapac

- ethyl

.

Exposure Scenario Crop or Target Dermal Unit Exposure ( μ g/lb ai) 1 Inhalation Unit

Exposure ( μ g/lb ai) 1 Maximum

Application

Rate 2 Area

Treated or

Amount

Handled Daily 3 Dermal Inhalation Total

Mitigation Level Mitigation Level Dose (mg/kg/day) 4 MOE 5 Dose (mg/kg/day) 6 MOE 7 MOE 8

Parks, etc.) (with gloves) (with gloves) (with gloves) (with gloves)

Backpack Application Edging/Banding for Landscaping Turf (Lawns, Athletic Fields, Parks, etc.) 8260 2.58 0.03 40 0. 11 540 0.0000449 1,300,000 540

Manually

– Pressurized

Handwand Edging/Banding

for Landscaping Turf (Lawns, Athletic Fields, Parks, etc.) 100000

30 0.03 40 1.35 (baseline) 44

(baseline)

0.000522 110,000 44 (baseline)

430 (with gloves) 0.0058 (with gloves) 10,000

(with gloves) 9,200 (with gloves)

Mechanically

- Pressurized Handgun Golf Course

(Tees and Greens Only) 1350 18 0.0 5 5 0.00 38 16,000 0.0000652 920,000 16,000

Mechanically

- Pressurized Handgun Golf Course

(Fairways, Tees, Greens) 1350 18 0.1 7 5 0.01 29 4,700 0.000222 270,000 4,600

Mechanically

- Pressurized Handgun Landscaping

Turf (Lawns, Athletic Fields, Parks, etc.) 1350 18 0.34 5 0.02 58 2,300 0.000443 140,000 2,300

Mechanically

- Pressurized Handgun Edging/Banding

for Landscaping Turf (Lawns, Athletic Fields, Parks, etc.) 1350 18 0.68 5 0.0 516 1,200 0.000887 68,000 1,200

Loading/Applying Granules

Belly Grinder Application Landscaping Turf (Lawns, Athletic Fields, Parks, etc.) 10000 62 0.88 1 0.0988 610 0.000791 76,000 610

Rotary Spreader Application Golf Course

(Tees and 440 10 0.44 5 0.0109 5,500 0.000319 190,000 5,300Page 30 of 41

Table 6.1.1. Occupational Handler Non

- Cancer Exposure and Risk Estimates for Trinexapac

- ethyl

.

Exposure Scenario Crop or Target Dermal Unit Exposure ( μ g/lb ai) 1 Inhalation Unit

Exposure ( μ g/lb ai) 1 Maximum

Application

Rate 2 Area

Treated or

Amount

Handled Daily 3 Dermal Inhalation Total

Mitigation Level Mitigation Level Dose (mg/kg/day) 4 MOE 5 Dose (mg/kg/day) 6 MOE 7 MOE 8

Greens Only)

Rotary Spreader Application Golf Course

(Fairways, Tees, Greens) 440 10 0.44 5 0.0109 5,500 0.000319 190,000 5,300

Rotary Spreader Application Landscaping

Turf (Lawns, Athletic Fields, Parks, etc.) 440 10 0.88 5 0.0218 2,800 0.000638 94,000 2,700

1 Based on the “Occupational Pesticide Handler Unit Exposure Surrogate Reference Table” ( March 2013 ); Leve l of mitigation: Baseline (single layer of clothing, no gloves, no respirator), Baseline with gloves, or Eng. Controls (EC; closed cockpit) for aerial applicators

. 2 Based on currently registered label s

. 3 Exposure Science Advisory Council Policy #9.1.

4 Dermal Dose = Dermal Unit Exposure ( μ g/lb ai) × Conversion Factor (0.001 mg/ μ g) × Application Rate (lb ai/acre or gal) × Area Treated or Amount Handled (A or gal/day) × DAF ( 77.5 %) ÷ BW ( 69 kg).

5 Dermal MOE = Dermal NOAEL ( 60 mg/kg/day) ÷ Dermal Dose (mg/ kg/day).

6 Inhalation Dose = Inhalation Unit Exposure ( μ g/lb ai) × Conversion Factor (0.001 mg/ μ g) × Application Rate (lb ai/acre or gal) × Area Treated or Amount Handled (A or gal/day) ÷ BW ( 69 kg).

7 Inhalation MOE = Inhalation NOAEL ( 60 mg/kg/day) ÷ Inh alation Dose (mg/kg/day).

8 Total MOE = NOAEL ( 60 mg/kg/day) ÷ Dermal Dose + Inhalation Dose.Page 31 of 41



### 6

. 2 Occupational Post

- 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 re

entry exposure). Such exposures may occur when workers enter previously treated areas to perform job functions, i ncluding activities related to crop production, such as scouting for pests or harvesting. Post

- application exposure levels vary over time and depend o n such things as the type of activity, the nature of the crop or target that was treated, the type of pes ticide application, and the chemical’s degradation properties. In addition, the timing of pesticide applications, relative to harvest activities, can greatly reduce the potential for 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 trinexapac

- ethyl at this time primarily because of the low acute inhalation toxicity (Toxicity Category III and IV)

. However, there are multiple potential sources of post

- application inhalation exposure to individuals performing post

- application activities in previously treated fields. These potential sources include volatilization of pesticides and resuspension of dusts and/or particulates that contain pesticides. The Agency sought expert advice and input on issues related to volatilization of pesticides from its Federal Insecticide, Fungicide, and Rodenticide Act Scientific Advisory Panel (SAP) in December 2009, and received the SAP’s final report on March 2, 2010 11



### . 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 polici es and procedures, to identify the need for and, subsequently, the way to incorporate occupational post

- application inhalation exposure into the Agency's risk assessments. If new policies or procedures are put into place, the Agency may

revisit the need f

or a quantitative occupational post

- application inhalation exposure assessment

for trinexapac

- ethyl

.

Although a quantitative occupational post

- application inhalation exposure assessment was not performed, an inhalation exposure assessment was performed fo r occupational/commercial handlers. Handler exposure resulting from application of pesticides outdoors is likely to result in higher exposure than post

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

- application inhalation exposure scenarios.

6

. 2 .2 Occupational Post

- application Dermal Exposure/Risk Estimates

Occupational Post

- application Dermal Exposure 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.

11 Available: http://www.epa.gov/scipoly/SAP/meetings/2009/120109meeting.htmlPage 32 of 41



### Exposure Duration: HED classifies exposures from 1 to 30 days as short

- term and exposures 30 days to six months as intermediate

- term. For trinexapac

- ethyl , based on the currently registered

use s , short

- and intermediate

- term exposure is expected

.

Transfer Coefficients : It is the policy of HED to use the best available data to asses s post

application exposure. Sources of generic post

- application data, used as surrogate data in the

absence of chemical

- specific data, are derived from ARTF exposure monitoring studies, and, as proprietary data, are subject to the data protection provisi ons 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 12 

### ” which, along with

additional information about the A RTF data, can be found at the Agency website 13



### .

Table 6

. 2 .2

. 1

. Anticipated Post

- Application Activities and Dermal Transfer Coefficients.

Crops Policy Crop

Group Category Crop

Height Foliage

Density Transfer

Coefficients (cm 2 /hr ) Activities

Golf Course Turf/sod Low Full 3700 Maintenance

Golf Course Turf/Sod Low Full 2500 Maintenance, greens only

Sod Turf/Sod Low Full 6700 Maintenance, Slab Harvesting, Transplanting/Planting

Sugarcane Sugarcane High Full 1100 Scouting

Sugarcane Sugarcane High Full 8800 Hand Harvesting

Sugarcane Sugarcane Low Minimum 70 Hand Weeding

Cereals (Wheat, Barley, Oats, Triticale) Field/row

crop, low/medium Low Full/Minimum 1100 Scouting

Cereals (Wheat, Barley, Oats, Triticale) Field/row

crop, low/medium Low Full/Minimum 70 Hand Weeding

Grasses Grown For

Seed Field/row

crop, low/medium Low Full 1900 Hand Set Irrigation

Grasses Grown For

Seed Field/row

crop, low/medium Low Minimum 1100 Scouting



### Application Rate: The maximum application rates, as detailed in Table 4.1, were used in the occupational pos t

- application calculations.

Exposure Time : The average occupational workday is assumed to be 8 hours.

Dislodgeable Foliar Residues :

12 Available: http://www.epa.gov/pesticides/science/exposac_policy 3.pdf

13 Available: http://www.epa.gov/pesticides/science/post

- app

- exposure

- data.htmlPage 33 of 41



### Chemical

- specific dislodgeable foliar residue (DFR) d ata have not been submitted f or trinexapac

- ethyl

. Therefore, the assessment uses HED’s default assumption that 25% of the appli cation is available for transfer on day 0 following the application and the residues dissipate

at a rate of 10% each following day.

Chemical

- specific TTR da ta are available for trinexapac

- ethyl and were used in the occupational
post

- application exposure assessment to assess turf in conjunction with standard default assumptions to assess sugarcane, cereals (wheat, barley, oats, triticale), and grasses grown for

seed. Therefore, the assessment uses surface residues from the day of application (assume that individuals could be exposed to residues imme diately after application ) for occupational turf uses (see Appendix B for more details).

Occupational Post

- application Non

- Cancer Dermal Exposure and Risk Estimate Equations The algorithms used to estimate non

- cancer exposure and dose for occupational post

- application workers can be found in Appendix A

.

Occupational Post

- application Non

- Cancer Dermal Risk Estimates

The short

- and intermediate

- term occupational post

- application dermal exposure and risk

estimates indicate that the MOEs are not of concern to HED (i.e., MOEs ≥ 100) on the day of application , except for hand

- harvesting sugarcane (MOE=87) where risk estimate s are of concern until 2 days after application (MOE=110) as detailed in Table 6.2.2.2.

Table 6

. 2 .2.2

. Occupational Post

- applica tion Non

- Cancer Exposure and Risk Estimates for Trinexapac

ethyl

.

Crop/Site Activities Transfer Coefficient (cm 2 /hr) DFR/TTR 1 Dermal Dose (mg/kg/day) 2 MOE 3

Short

- term

/Intermediate

- term

Granular Formulation

Golf Course (Turf/Sod) Maintenance 3700 0.015 0.005 12,000

Golf Course (Turf/Sod) Maintenance, Greens Only 2500 0.015 0.003 18,000

Liquid Formulations

Golf Course (Turf/Sod) Maintenance 3700 0.006 0.002 29,000

Golf Course (Turf/Sod) Maintenance, Greens Only 2500 0.006 0.001 43,000

Sod (Turf/Sod) Maintenance,

Harvesting, Slab, Transplanting 6700 0.012 0.008 8,000

Sugarcane Scouting 1100 0.87 0.086 700

Sugarcane Hand Harvesting 8800 0.87 0.688 87 (MOE=110 at Day 2 after

treatment )

Sugarcane Hand Weeding 70 0.87 0.005 11,000

Cereals (Wheat, Barley, Oats, Triticale) Scouting 1100 0.31 0.030 2,000

Cereals (Wheat, Barley, Oats, Triticale) Hand Weeding 70 0.31 0.002 31,000Page 34 of 41

Table 6

. 2 .2.2

. Occupational Post

- applica tion Non

- Cancer Exposure and Risk Estimates for Trinexapac

ethyl

.

Crop/Site Activities Transfer Coefficient (cm 2 /hr) DFR/TTR 1 Dermal Dose (mg/kg/day) 2 MOE 3

Short

- term

/Intermediate

- term

Grasses Grown For

Seed Hand Set Irrigation 1900 1.40 0.239 250

Grasses Grown For

Seed Scouting 1100 1.40 0.139 430

1 DFR = Application Rate × F × (1

- D) t × 4.54E8 μg/lb × 2.47E

- 8 acre/cm 2 ; where F = 0.25 and D = 0.10 per day or TTR = chemical

- specific data from MRID 45260201 for the Indiana site adjusted for differences in application rates

2 Daily Dermal Dose = [DFR (μg/cm 2 ) × Transfer Coefficient × 0.001 mg/μg × 8 hrs/day × dermal absorption ( 77.5 %)] BW ( 69 kg).

3 MOE = POD ( 60 mg/kg/da y) / Daily Dermal Dose. Daily Dermal Dose = [DFR /TTR (μg/cm 2 ) × TC × 0.001 mg/μg × 8 hrs/day × dermal absorption factor ( 77.5 %) ] BW ( 69 kg)

.



### Restricted Entry Interval

The REI specified on the currently registered labels is based on the acute toxicity of trinexapac ethyl. Trinexapac

- ethyl is classified as Toxicity Category III via the dermal route and Toxicity Category IV for skin irritation potential. It is not a skin sensitizer. Short

- and intermediate

- term post

- application risk estimates were not a concern on day 0 (12 hours following application) for all post

- application activities. Under 40 CFR 156.208 (c) (2) (iii), ai ’s classified as Acute III or IV for acute dermal, eye irritation and primary skin irrigation are assigned a 12

- hour REI. Therefore, the [156 subpart K] Worker Protection Statement interim REI of 12 hours is adequate to protect agricultural workers from p ost

- application exposures to trinexapac

- ethyl

.Page 35 of 41



### Appendix A. Summary of Occupational and Residential Non

- cancer Algorithms

Residential Non

- cancer Handler Algorithms

Daily dermal and inhalation exposure (mg/day) for residential pesticide handlers, for a given

formulation

- application method combination, is estimated by multiplying the formulation

application method

- specific unit exposure by an estimate of the amount of active ingredient handled in a day, using the equation below:

E = UE * AR * A

wh ere:

E = exposure (mg/day); UE = unit exposure (mg/lb ai); AR = application rate (e.g., lb ai/ft 2 

### , lb ai/gal); and A = area treated or amount handled (e.g., ft 2 

### /day, gal/day).

1.2 Residential Handler Dose Calculations

Dermal and/or inhalation absorbed d oses normalized to body weight are calculated as:

D = E *AF / BW

where:

D = dose (mg/kg

- day); E = exposure (mg/day); AF = absorption factor (dermal and/or inhalation); and BW = body weight (kg).

Residential Non

- cancer Post

- application Algorithms

Post

- application Dermal Exposure Algorithm

– Physical Activities on Turf

Exposure resulting from contacting previously treated turf while performing physical activities is calculated as shown below. Residential post

- application exposure assessment must include calculation of exposure on the day of application. Therefore, though an assessment can present exposures for any day “t” following the application, it must include “day 0” exposure.

E = TTRt * CF1 * TC * ET

where:

E = exposure (mg/day);

TTRt = turf transferable residue on day t (μg/cm 2 

### ); CF1 = weight unit conversion factor (0.001 mg/μg);Page 36 of 41



### TC = transfer coefficient (cm 2 

### /hr); and ET = exposure time (hr/day).

C hemical

- specific TTR data are available,

Dermal absorbed doses are calculated as:

where:

D = dose (mg/kg

- day);

E = exposure (mg/day);

AF = absorption factor (dermal); and

BW = body weight (kg).

Table A

- 2: Turf (Physical Activities)

-- Inputs for Residential Post

- application Dermal Exposure

Algorithm Notation Exposure Factor (units) Point Estimate(s)

TC Transfer

Coefficient (cm 2 /hr) L/WP/WDG Adults 180,000
Children 1 < 2 years old 49,000

Granules Adults 200,000

Children 1 < 2 years old 54,000

ET Exposure Time

(hours per day) Adults 1.5

Children 1 < 2 years old 1.5

BW Body Weight (kg) Adults 69

Children 1 < 2 years old 11 L/WP/WDG = Liquids/Wettable Powders/Water

- dispersible Granules



### Post

- application Dermal Exposure Algorithm

– Mowing Exposure resulting from contacting previously treated turf while mowing is calculated as

follows:

E = TTRt * CF1 * TC * ET

where :

E = exposure (mg/day);

TTR t 

### = turf transferable residue on day "t" (μg/cm 2 

### ); CF1 = weight unit conversion factor (0.001 mg/μg); TC = transfer coefficient (cm 2 

### /hr); and

ET = exposure time (hr/day).

and

TTRt = AR * F AR 

### * (1

- F

D 

### ) t 

### * CF2 * CF3Page 37 of 41



### where :

TTR t 

### = turf transferable residue on day "t" (μg/cm 2 

### ); AR = application rate (lbs ai/ft 2 

### or lb ai/acre);

F AR 

### = fraction of ai retained on turf (unitless);

F D 

### = fraction of re sidue that dissipates daily (unitless);
t = post

- application day on which exposure is being assessed; CF2= weight unit conversion factor (4.54 x 10 8 

### μg/lb); and CF3 = area unit conversion factor (1.08 x 10 - 3 

### ft 2 

### /cm 2 

### or 2.47 x 10 - 8 

### acre/cm 2 

### ).

Absorbed dose , normalized to body weight, are calculated as:

where : D = dose (mg/kg

- day);

E = exposure (mg/day);

AF = absorption factor (dermal); and

BW = body weight (kg).

Table A

- 6: Turf (Mowing)

– Inputs for Residential Post

- application Dermal Exposure

Algorithm Notation Exposure Factor (units) Point Estimate(s)

TC Transfer Coefficient (cm 2 /hr) Adult 5,500

Children 11 < 16 years

old 4,500

ET Exposure time (hours per day) 1

BW Body Weight (kg) Adults 69

Children 11 < 16 years

old 57

L/WP/WDG = liquid/wettable powder/water dispersible granule



### Post

- application Dermal Exposure Algorithm

– Golfing Exposure resulting from contacting previously treated turf while golfing is calculated as follows:

E = TTRt * CF1 * TC * ET

where :

E = exposure (mg/day);

TTR t 

### = turf transferable residue on day "t" (μg/cm 2 

### ); CF1 = weight unit conversion factor (0.001 mg/μg); TC = transfer coefficient (cm 2 

### /hr); and ET = exposure time (hr/day).

andPage 38 of 41 

### TTRt = AR * F * (1

- F D 

### ) t 

### * CF2 * CF3

where :

TTR t 

### = turf transferable residue on day "t" (μg/cm 2 

### ); AR = application rate (lbs ai/ft 2 

### or lb ai/acre); F = fraction of ai retained on turf (unitless);’

F D 

### = fraction of residue that dissipat es daily (unitless);
t = post

- application day on which exposure is being assessed; CF2 = weight unit conversion factor (4.54 x 10 8 

### μg/lb); and CF3 = area unit conversion factor (1.08 x 10 - 3 

### ft 2 

### /cm 2 

### or 2.47 x 10 - 8 

### acre/cm 2 

### ).

Absorbed dose, normalized to bo dy weight, is calculated as:

where : D = dose (mg/kg

- day);

E = exposure (mg/day);

AF = absorption factor (dermal); and

BW = body weight (kg).

Table A

- 7: Turf (Golfing)

– Inputs for Residential Post

- application Dermal Exposure Algorithm

Notation Exposure Factor (units) Point Estimate(s)

TC Transfer Coefficient

(cm 2 /hr) Adult 5,300 Children 11 < 16 years old 4,400 Children 6 < 11 years old 2,900

ET Exposure time

(hours per day) Pesticides used on greens, tees, and fairways 4

Pesticides used only on greens

and tees 1

BW Body Weight (kg) Adults 69

Children 11 < 16 years old 57 Children 6 < 11 years old 32 NA = not applicable L/WP/WDG = liquid/wettable powder/water dispersible granule



### Occupational Non

- cancer Handler Algorithms

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

where:

E = e xposure (mg ai/day),

UE = u nit e xposure (μ g ai/ lb ai),Page 39 of 41



### AR = m aximum applica tion rate according to registered label s (lb ai A or lb ai/gal ), and

A = a rea treated or amount handled (e.g., A/day, gal/day)

.

The daily doses are calculated using the following formula:

where:

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

E = e xposure (mg ai/day),

AF = absorption fa ctor (dermal and/or inhalation), and

BW = body weight (kg)

.

Margin of Exposure: Non

- cancer risk estimates for each application handler scenario are

ca lculated 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 a re compared to the appropriate POD ( i.e.

, NOAEL) to assess the risk to occupational handlers for each exposure route. All MOE values a re calculated using the following formula:

where:

MOE = m argin of e xposure: value used by HED to represent risk estimates (unitless),

POD = p oint of d eparture (mg/kg/day)

, and

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

.

Occupational Non

- cancer Post

- application Algorithms

Potential daily exposures for occupational post

- application workers are calculated using the following formulas:

where:

DFR t 

### = dislodgeable foliage residue on day "t" (μg/cm 2 

### ),

AR = a pplication r ate (lb ai/acre),

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

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

t = number of days after application day (days)

.Page 40 of 41



### where:

E = e xposure (mg ai/day),

TC = t ransfer coefficient (cm 2 

### /hr),

DFR t 

### = d islodgeable f oliar r esidue on day “t” (μg/cm 2 

### ), and

ET = e xposure t ime (hours/day).

The daily doses are calculated using the following formula:

where:

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

E = e xposure (mg ai/day),

AF = absorption fa ctor (dermal and/or inhalation), and

BW = body weight (kg).

Margin of Exposure: Non

- cancer risk estimates for each scenario are calculated using a Margin of Exposure (MOE), which is a ratio of the toxicological endpoint to the daily dose of concern. The daily dermal dose received by occu pational post

- application workers is compared to the appropriate POD ( i.e.

, NOAEL) to assess the risk to occupational post

- application workers

. All

MOE values a re calculated using the following formula:

where:

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

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

ADD = average daily dose absorbed in a given scenario (mg ai/kg/day).Page 41 of 41



### Appendix B. Summary of the TTR Study: Determination of Transfe rable Residues of
Trinexapac

- ethyl Turf Treated with Primo Maxx (MRID 45260201 )

The study was designed to determine the total tran s ferable residues (TTR) of trinexapac

- ethyl dislodged from turf treated with Primo Maxx, a microemulsion concentrat e containi ng 11.3% trinexapac

- ethyl as the active ingredient. The test site consisted of one treated plot located in Georgia, California, and Indiana

. The treated plot was divided into subplots and three replicate samples were collected at each sampling interval. Applications were made at a rate of 0.69 lb

ai/A to the treated plot (maximum application rate for edging/banding), which is twice the

maximum broadcast application rate of 0.35 lb ai/A. The application was made as a ground application to a single treatment plot at each site using a water carrier through a turf handgun

sprayer. The Modified California Roller technique was used to evaluate the amount of transferable residues from turf grass

. First

- order dissipation kinetics were assumed to generate dissipation curves for trinexapac

- ethyl at the test sites. The individual residue data w ere collected after the last application through the first day when all triplicate TTR levels were less than the level of quantitation (LOQ). For values that were less than the LOQ, a value was used

that is one

- half of the LOQ. A linear regression analysis was conducted using the natural logarithm of the individ ual TTR values from cloth dosimeters.

At the Indiana test site, the average trinexapac

- ethyl TTR value on Day 0 was 0.05 4 ug/cm 2



### . At the California test site, the average trinexapac

- ethyl TTR value on Day 0 was 0.024 ug/cm 2



### . At the Georgia test site, t he average trinexapac

- ethyl TTR value on Day 0 was 0.03 8 ug/cm 2



### . The average TTR values were highest immediately after application for all sites.

Based on the study results, the half

- life was determined to be 11.1 hours (R 2 

### =0. 893 ) for Indiana,

1 3

. 3 hours (R 2 

### =0.9 44 ) for Califor nia, and 7

. 6 hours (R 2 

### =0.9 84 ) for Georgia.

The results of the study are acceptable for risk assessment purposes.

Table B1. Summary of TTR Values and Regression Analysis Results for Treated Turf with Primo Maxx (MRID# 45260201 ).

Input/Parameter Georgia California Indiana

Application Rate (lb ai/A) 0.69 0.69 0.69

Spray Volume (GPA) 145 124.8 114

Measured Average Day 0 Residue (μg/cm 2 ) 0.03 8 0.024 0.05 4

Predicted Day 0 Residue (μg/cm 2 ) 0.031 0.018 0.02 3

Slope

- 2. 20

- 1.25

- 1. 50

Half

- life (days) 0.3 15 0. 553 0. 464

R 2 0.98 4 0.9 44 0. 893