UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGTON, D. C. 20460 OFFICE OF PREVENTION, PESTICIDES AND TOXIC SUBSTANCES Date: July 15, 2001 MEMORANDUM SUBJECT: REVISED OCCUPATIONAL AND RESIDENTIAL EXPOSURE ASSESSMENT AND RECOMMENDATIONS FOR THE REREGISTRATION ELIGIBILITY DECISION DOCUMENT FOR OXADIAZON FROM: Seyed Tadayon, Chemist Chemistry Exposure Branch I Health Effect Division ( 7509C)

THRU: Francis Suhre, Senior Scientist Chemistry Exposure Branch I Health Effects Division ( 7509C)

TO: Nancy McCarroll, Geneticist Toxicology Branch I Health Effects Division ( 7509C)

Please find the review of oxadiazon. DP Barcode: D276360 PC Codes: 109001 EPA Reg Nos: 264 450, 264 502, 432 886, 432 887, 432 893, 432 898, 538 143, 538 146, 538 147, 538 164, 538 241, 538 257, 961 340, 961 371, 961 379, 961 380, 961 382, 8660 17, 8660 35, 8660 36, 9198 75, 9198 154, 9198 155, 10404 63, 10404 93, 34704 771, 35512 43, 35512 44, 48234 1, 48234 2, 48234 10, 48234 14, 48234 15, 52287 1, 52287 2, 52287 3, 55615 4, 55615 5, 67508 1, CA97001800, FL82004500, HI97000100.

EPA MRID No: 449955 01, 449955 02, 435178 01 LUIS Report: 05/ 04/ 99 PHED: Yes, Version 1.1 2 CONTENTS EXECUTIVE SUMMARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.0 BACKGROUND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 1.1 Summary of Toxicity Concerns Relating to Agricultural Exposures . . . . . . . . . . . . 6 1.2 Summary of Use Pattern and Formulations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 1.3 Method and Types of Equipment Used for Mixing/ Loading/ Applying . . . . . . . . . 10 1.4 Incident Reports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 2.0 OCCUPATIONAL EXPOSURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 2.1 Handler Exposures & Assumptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 2.1.1 Summary of Occupational Handler Exposures . . . . . . . . . . . . . 14 2.1.2 Summary of Uncertainties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 2.1.3 Calculations of Exposure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 2.1.4 Calculations of Cancer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 2.2 Risk From Handler Exposures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 2.2.1 Risk From Handler Exposures . . . . . . . . . . . . . . . . . . . . . . . . . 20 2.2.2 Summary of MOEs and cancer . . . . . . . . . . . . . . . . . . . . . . . . . 22 3.0 POSTAPPLICATION EXPOSURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 3.1 Postapplication Exposures & Assumptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 3.1.1 Data Source and Assumptions For Scenario Considered . . . . . . 27 3.1.2 Assumptions Used in Postapplication Exposure . . . . . . . . . . . . 28 3.1.3 Exposure and Risk Calculation . . . . . . . . . . . . . . . . . . . . . . . . . 28 3.1.4 Postapplication Exposure Risk estimates . . . . . . . . . . . . . . . . . . 29 3.2 Non occupational Postapplication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 3.2.1 Postapplication Exposure Scenarios . . . . . . . . . . . . . . . . . . . . . 30 3.2.2 Data Sources for Scenarios Considered . . . . . . . . . . . . . . . . . . 30 3.2.3 Assumptions Used in Postapplication Exposure Calculations . . 31 3.2.4 Postapplication Exposure Risk Estimates . . . . . . . . . . . . . . . . . 36 3.2.5 Data Gaps and Uncertainties . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 APPENDIX A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 APPENDIX B . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 APPENDIX C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 EXECUTIVE SUMMARY 3 Purpose This is a revision of the original Occupational and Residential Exposure Assessment and Recommendations Document for Oxadiazon, ( S. Tadayon June 12, 2001). This chapter has been revised to address comments made by the Risk Assessment Review Committee ( RARC).

This document addresses the exposures and risks associated with the use of the oxadiazon, that occur through non dietary exposure. These exposures can occur as a result of applying oxadiazon or by entering areas that have been previously treated with oxadiazon. Exposures can occur as a part of one's job or through uses of oxadiazon on residential lawns and other areas that are frequented by the general public. Occupational and residential exposures are addressed separately in this document.

Oxadiazon, 2 tert butyl 4 ( 2,4 dichloro 5 isopropoxyphenyl 1,3,4 oxadiazolin 5 one), is a selective pre emergence and early post emergence herbicide used primarily to control annual grasses and broadleaf weeds. The occupational use sites include golf course turf, ornamental turf, conifer nursery, landscape  industrial sites, ornamental noncroplands, roadside landscape plantings, sod farms, woody ornamental shrubs, vines and trees and herbaceous ornamental crops. The outdoor residential use site include cemeteries, athletic fields, residential condominiums and school ground. A wide variety of application techniques have been identified that could potentially be used to apply oxadiazon such as groundboom sprayers, handheld sprayers ( low and high pressure devices and low pressure/ high volume sprayguns commonly used on turf), backpack sprayers, tractor drawn granular spreaders, push type granular lawn spreaders, and bellygrinders. Oxadiazon is formulated as a manufacturing product ( 94.0% active ingredient), several granular formulations ( up to 50.0% active ingredient) and three wettable powders ( 50.0% active ingredient).

Hazard Identification The Report of the Hazard Identification Assessment Review Committee ( HIARC) for oxadiazon, dated December 21, 2000, indicates that there are toxicological endpoints of concern for oxadiazon. A short term ( 1 7 days) to intermediate term ( one week to several months) oral endpoint was selected for incidental oral exposure in children, using a NOAEL of 12 mg/ kg/ day based on a statistically significant decrease in maternal body weight gains at 40 mg/ kg/ day ( LOAEL) in a developmental study in rats.

For short term and intermediate dermal exposure, an oral endpoint was selected using a NOAEL of 12 mg/ kg/ day based on a statistically significant decrease in maternal body weight gains at 40 mg/ kg/ day ( LOAEL) in a developmental study in rats. The committee recommended a dermal absorption factor of 9% ( rounded up from 8.7%) based on a dermal penetration study to be used in the calculation.

Due to a lack of inhalation studies, the HIARC selected an endpoint from oral studies for 4 inhalation risk assessments. For short and intermediate term inhalation exposure, the same oral study was chosen as for dermal exposure of this duration, with a NOAEL of 12 mg/ kg/ day. An absorption factor of 100% is applied for inhalation exposures. The target margin of exposure ( MOE) of 100 or more for occupational exposure scenarios was selected based upon 10x for intraspecies and 10x for interspecies variation. Because the effects from dermal and inhalation exposure are the same, the doses for these routes and duration may be aggregated.

Since 1987, the Agency's decision on the carcinogenic potential of oxadiazon concurred with the Scientific Advisory Panel's ( SAP) classification of oxadiazon as a Group C carcinogen and the Q 1* had been set at 1.4 x 10 1( mg/ kg/ day) 1 in human equivalents. Since that time, new chronic/ carcinogenicity data have been submitted and reviewed by the Cancer Assessment Review Committee ( CARC). Based on this revisit, CARC has reclassified oxadizon as a " Likely To Be Carcinogenic To Humans". For the purpose of the lifetime cancer risk assessment by the Agency, the most potent unit risk, Q 1 *, is that for male mouse liver adenoma and/ or carcinoma combined tumor rates at 7.11 x 10 2 ( mg/ kg/ day) 1 in human equivalents. All unit risks have been converted from animals to humans by use of the 3/ 4' s scaling factor.

Oxadiazon has not been reported to cause life threatening illness or death. Most of the cases appear to be related to irritation to the skin, eyes and mucous membranes. Some cases may be related to an allergic reaction On the list of the top 200 chemicals for which NPTN ( National Pesticide Telecommunications Network) received calls from 1984 1991 inclusively, oxadiazon was ranked 192nd with 12 incidents in humans reported and 5 incidents in animals ( mostly pets).

Occupational Handler Exposure and Risk Estimates HED has determined that there are potential exposures to mixers, loaders, applicators, and other handlers during usual use patterns associated with oxadiazon. Fourteen major exposure scenarios were identified for oxadiazon, including mixing, loading, and applying using ground spray, granular, and lawn application methods.

Handler Scenarios with Risk Concerns The results of the short and intermediate term handler assessments indicate that all potential exposure scenarios provide at least one application rate with a total MOE( s) greater than or equal to 100 at either the baseline ( i. e., long pants, long sleeved shirts, no gloves) using open systems, PPE ( i. e., long pants, long sleeved shirts, and chemical resistant gloves while using open systems) or using engineering controls ( i. e., closed systems). In the majority of cases, it is dermal exposure rather than the inhalation exposure driving the total MOEs. In total, 37 MOEs were calculated for the various application rates. The total MOEs for all the scenarios range from 2 to 3000.

The results of the Cancer Risk indicate that the values range from 1.65E 2 to 4.66E 7 at the baseline ( i. e. long pants, long shirts and no gloves), 2.56E 3 to 4.11E 7 at PPE1 ( i. e. long 5 pants, long shirts, gloves and no respirator), 2.40E 3 to3.51E 7 at PPE2 ( i. e. long pants, long shirts, double layer, gloves and no respirator), 1.05E 3 to 1.98E 7 at PPE3 ( i. e. long pants, long shirts, gloves and respirator), 8.90E 4 to 1.38E 07 at PPE4 ( i. e. long pants, long shirts, double layer, gloves and respirator) and 4.92E 5 to 1.10E 8 at engineering control.

Postapplication Worker Exposure and Risk Estimates Most of the oxadiazon used on golf course turf ( 71%), ornamental turf, conifer nursery, landscape  industrial sites, ornamental non croplands, roadside landscape planting, sod farms, woody ornamental shrubs, vines and trees and herbaceous ornamental crops is applied early in the season, either pre plant or before weeds emerge ( pre emergence). This fact, and the degree of mechanization in cultivating these crops, minimizes the postapplication contact of workers with the chemical on these crops. Three chemical specific studies, were submitted to the Agency for consideration. Theses studies were reviewed and only the re entry study found to be acceptable for use in the oxadiazon risk assessment.

Using the revised residential SOP postapplication short and intermediate term dermal risk estimates for occupational workers are between 30 and 1,000. The cancer risk for all occupational handlers is between 9.92 x 10 5 to 3.01 x 10 6.

Residential Postapplication Exposure and Risk Estimates Dermal postapplication exposure estimates were conducted using the highest mean postapplication residue from the Jazzercise study ( wettable powder formulations). The dermal transfer coefficients from the Jazzercize study and the revised residential SOPs were used. Using the Jazzercize wettable powder application study residue data and revised residential SOPs , all of the scenario had short term and intermediate dermal MOEs greater than 100. The cancer risks for all residential dermal postapplication is between 6.22x 10 6 to 7.51 x 10 7 .

The Residential SOPs and submitted Jazzercize study data were used to estimate incidental oral exposure for toddlers on treated turf. The short term MOE was100 for the toddler hand to mouth using residential SOPs and between 90 to 240 for the submitted study. The intermediate term MOE was not calculated since exposure by this route for weeks to months is considered less likely to occur than short term exposure. Incidental turfgrass mouthing and soil ingestion had MOEs greater than 100 for short term exposures.

Uncertainties in Risk Assessment and Data Gaps Residential handler exposure and risk estimates were conducted using a set of surrogate chemical data: the ORETF study data and the Residential SOPs. Dermal postapplication exposures to oxadiazon were based on the highest residues from the chemical specific re entry study data and are of fairly high confidence. Oral ingestion scenarios are based on standard assumptions and formulae ( Residential SOPs) which are designed to be screening level. Granular 6 ingestion is considered episodic in nature.

1.0 BACKGROUND Purpose In this document, which is for use in EPA's development of the oxadizon. Reregistration Eligibility Decision Document ( RED), EPA presents the results of its review of the potential human health effects of occupational and residential exposure to oxadiazon.

Criteria for Conducting Exposure Assessments An occupational and/ or residential exposure assessment is required for an active ingredient if ( 1) certain toxicological criteria are triggered and ( 2) there is potential exposure to handlers ( mixers, loaders, applicators, etc.) during use or to persons entering treated sites after application is complete. For oxadiazon, both criteria are met.

1.1 Summary of Toxicity Concerns Relating to Agricultural Exposures Acute Toxicology Categories Table 1 presents the acute toxicity categories as outlined in the Hazard Identification Document ( Dec 21, 2000). 1 Table 1: Acute Toxicity Categories For Oxadiazon Guideline No. Study Type MRID #( S). Results Toxicity Category 81 1 Acute Oral Rat 41866501 LD50 = > 5000 mg/ kg (

 , combined) IV 81 2 Acute Dermal Rabbit 41866502 LD50 = > 2000 mg/ kg (

 , combined) III 81 3 Acute Inhalation Rat 41866503 LC50 = > 1.94 mg/ L (

 , combined) III 81 4 Primary Eye Irritation Rabbit 41866504 Mild irritant to ocular tissue III 81 5 Primary Skin Irritation Rabbit 41866505 Negligibly irritating to skin III 81 6 Dermal Sensitization Guinea Pig 41230401 Not a dermal sensitizer ( Buehler test)

81 8 Acute Neurotoxicity ND Other Endpoints of Concern The report of the Hazard Identification Assessment Review Committee ( HIARC) for oxadiazon, dated Dec 21, 20001, identified toxicological endpoints of concern for oxadiazon. 7 All calculations completed in this document are based on the most current toxicity information available for oxadiazon. The endpoints that were used to complete this assessment are summarized below in Table 2:

Table 2: Endpoints selected by HIARC for Assessing Occupational and Residential Risks for Oxadiazon EXPOSURE SCENARIO DOSE ( mg/ kg/ day) ENDPOINT STUDY Incidental Oral, Short Term NOAEL= 12 Maternal effects Reduced body weight/ body weight gain at 40 mg/ kg/ day ( LOAEL). Developmental Toxicity  Rat MRID No. 40470202 Incidental Oral, Intermediate Term NOAEL= 12 Maternal effects Reduced body weight/ body weight gain at 40 mg/ kg/ day ( LOAEL). Developmental Toxicity  Rat MRID No. 40470202 Dermal, Short Term NOAEL= 12 Maternal effects/ Developmental effects Reduced body weight/ body weight gain at 40 mg/ kg/ day ( LOAEL) / Increased fetal resorptions/ postimplantation loss, increased incidence of incomplete ossification at 40 mg/ kg/ day ( LOAEL). For this risk assessment, the dermal absorption rate of 9% is applied. Developmental Toxicity  Rat MRID No. 40470202 Dermal, Intermediate Term NOAEL= 12 Maternal effects/ Developmental effects Reduced body weight/ body weight gain at 40 mg/ kg/ day ( LOAEL) / Increased fetal resorptions/ postimplantation loss, increased incidence of incomplete ossification at 40 mg/ kg/ day ( LOAEL). For this risk assessment, the dermal absorption rate of 9% is applied. Developmental Toxicity  Rat MRID No. 40470202 Dermal, Long Term NOAEL= 0.36 Reduced body weight/ body weight gain at 40 mg/ kg/ day ( LOAEL) / Increased centrilobular swelling in male livers at 3.5 mg/ kg/ day ( LOAEL). For this risk assessment, the dermal absorption rate of 9% is applied. Combined Chronic Feeding/ Oncogenicity  Rat MRID Nos. 40993401, 00149003/ 00157780 Inhalation, Short Term NOAEL= 12 Maternal effects/ Developmental effects Reduced body weight/ body weight gain at 40 mg/ kg/ day ( LOAEL) / Increased fetal resorptions/ postimplantation loss, increased incidence of incomplete ossification at 40 mg/ kg/ day ( LOAEL). For this risk assessment, route to route extrapolation and a 100% absorption rate are applied Developmental Toxicity  Rat MRID No. 40470202 Inhalation, Intermediate Term NOAEL= 12 Maternal effects/ Developmental effects Reduced body weight/ body weight gain at 40 mg/ kg/ day ( LOAEL) / Increased fetal resorptions/ postimplantation loss, increased incidence of incomplete ossification at 40 mg/ kg/ day ( LOAEL). For this risk assessment, route to route extrapolation and a 100% absorption rate are applied. Developmental Toxicity  Rat MRID No. 40470202 Inhalation, Long Term NOAEL= 0.36 Increased centrilobular swelling in male livers at 3.5 mg/ kg/ day ( LOAEL). Route to route extrapolation and a 100% absorption rate aplied. Combined Chronic Feeding/ Oncogenicity  Rat MRID Nos. 40993401, 00149003/ 00157780 Cancer Q 1* of 7.11 x 10 2 ( mg/ kg/ day) 1 Significant increase ( pair wise and trend, p< 0.01) in liver adenomas and adenomas and/ or carcinomas combined in males at

9.3 mg/ kg/ day). Combined Chronic Feeding/ Carcinogenicity  Mouse MRID Nos. 40993301 1.2 Summary of Use Patterns and Formulations At this time, products containing oxadiazon are intended for both occupational and residential uses. 8 Type of pesticide/ target pests Oxadiazon, 2 tert butyl 4 ( 2,4 dichloro 5 isopropoxyphenyl 1,3,4 oxadiazolin 5 one), is a selective pre emergence and early post emergence herbicide used primarily to control annual grasses and broadleaf weeds. Table 3 presents a list of oxadiazons ' s active products. The annual grasses and broadleaves controlled by oxadiazon include the following:

1. Annual grasses: annual blugrass, barnyardgrass, crabgrass, fall panicum, giant foxtail ( yellow and green), goosegrass, junglerice, signalgrass, sprangletop, Texas panicum and hophornbeam copperleaf $ Broadleaves: Florida beggarweed, carpet weed, cudweed, dayflower, ducksalad, filaree, groundsel, jimsonweed, lambersquarters, mustards, pigweed, prickly sida, prostrate knotweed, purslane, purslane, redmaids, smartweed, sowthistle, velvetleaf, morningglory and black night shade Formulation types and percent active ingredient Oxadiazon is formulated as a manufacturing product ( 94.0% active ingredient), several granular formulations ( up to 50.0% active ingredient) and three wettable powders ( 50.0% active ingredient). Wettable powders are marketed in bags and water soluble bags.

Registered use sites, application rates and frequency of application Oxadiazon is applied as a pre plant or pre emergent herbicide on non food/ outdoor crops. occupational applications ( i. e., to turf and ornamentals) are made to established areas such as lawns or golf course greens prior to the emergence of the target plant species. Residential/ nonoccupational applications are made to residential lawns, parks, cemeteries, schools, athletic fields and golf courses. The frequency of application ranges from 1 to 3 applications per season. Oxadiazon can be applied at a minimum application rate of 2.0 pounds of active ingredient per acre up to a maximum application rate of 4.0 pounds active ingredient per acre to turf and ornamentals. Oxadiazon use sites are non food crops ( primarily golf course greens, 77% of all use), residential outdoor use ( approximately 12% of all use), roadside ( approximately 3% of all use) and nurseries ( approximately 8% of all use). The granular formulations account for 91% of the total oxadiazon use ( turf use).

Table 3 represents information on registered use sites, products name, application rates, percent active ingredient and frequency of application per growing season for oxadiazon2. Application rate covers various type of equipment used to apply oxadiazon.

Table 3: Use Patterns, Application Rate, and Frequency of Application for Oxadiazon Reg No A. I % Product Name Crop Type Max Appl rate No of Appl per/ y 10404 63 0.95 Lesco Turfic for Crabgrass with Ronstar G turf: golf course 4 lb ai/ acre 3 10404 63 0.95 Lesco Turfic for Crabgrass with RonstarG turf: ornamental 4 lb ai/ acre 3 10404 93 0.63 Ronstar Weed and Feed 63 G nursery: woody ornamental shrubs, vines and trees 4 lb ai/ acre 3 9 10404 93 0.63 Ronstar Weed and Feed 63 G nursery: woody ornamental shrubs, vines and trees 4 lb ai/ acre 3 10404 93 0.63 Ronstar Weed and Feed 63 G turf: golf course 4 lb ai/ acre 3 10404 93 0.63 Ronstar Weed and Feed 63 G turf: ornamental ( parks, athletic fields, recreational) 4 lb ai/ acre 3 10404 93 0.63 Ronstar Weed and Feed 63 G turf: sod farms 4 lb ai/ acre 3 264 445 2 Chipco Ronstar G nursery: conifer 4 lb ai/ acre 1 264 445 2 Chipco Ronstar G nursery: woody ornamentals, shrubs, vines and trees 4 lb ai/ acre 1 264 445 2 Chipco Ronstar G turf: golf course 4 lb ai/ acre 1 264 445 2 Chipco Ronstar G turf: lawns 4 lb ai/ acre 1 264 445 2 Chipco Ronstar G turf: ornamental ( parks) 4 lb ai/ acre 1 264 450 94 oxadiazon technical Formulating use only 264 502 50 Ronstar 50% Intermediate Formulating use only 264 538 50 Chipco Ronstar 50 WSP landscape: woody ornamental shrubs, vines and trees 2 lb ai/ acre 1 264 538 50 Chipco Ronstar 50 WSP nursery: conifer 4 lb ai/ acre 1 264 538 50 Chipco Ronstar 50 WSP nursery: woody ornamental shrubs, vines and trees 4 lb ai/ acre 1 264 538 50 Chipco Ronstar 50 WSP turf: golf course ( no tees and greens) 3 lb ai/ acre 3 264 538 50 Chipco Ronstar 50 WSP turf: ornamental ( parks) 3 lb ai/ acre 3 264 538 50 Chipco Ronstar 50 WSP turf: sod farms in HI 3 lb ai/ acre 3 34704 771 2 Napropamide Oxadiazon 4 2 Granules landscape: woody ornamental shurbs vines and trees 3 lb ai/ acre 34704 771 2 Napropamide Oxadiazon 4 2 Granules nursery: conifer 3 lb ai/ acre 34704 771 2 Napropamide Oxadiazon 4 2 Granules nursery: woody ornamental shurbs vines and trees 3 lb ai/ acre 35512 43 1 Turf Pride Fertilizer with Ronstar 5 20G turf: golf course 4 lb ai/ acre 1 35512 43 1 Turf Pride Fertilizer with Ronstar 5 20G turf: ornamental ( parks, athletic fields, recreational) 4 lb ai/ acre 1 35512 43 1 Turf Pride Fertilizer with Ronstar 5 20G turf: sod farms 4 lb ai/ acre 1 35512 44 1 RegalstarG turf: established 2 lb ai/ acre 1 35512 44 1 RegalstarG turf: golf course 2 lb ai/ acre 1 48234 1 1 RegalstarG turf: established 2 lb ai/ acre 1 48234 1 1 RegalstarG turf: golf course ( not greens) 2 lb ai/ acre 1 48234 10 1 Regal O Herbicide G landscape: woody ornamental shrubs, vines and trees 3 lb ai/ acre 48234 10 1 Regal O Herbicide G nursery: woody ornamentals shrubs, trees, vines 3 lb ai/ acre 48234 10 1 Regal Ronstar Plus I G nursery: woody ornamentals shrubs, trees, vines 4 lb ai/ acre 3 48234 10 1 Regal Ronstar Plus I G turf: golf course 4 lb ai/ acre 1 48234 10 1 Regal Ronstar Plus I G turf: ornamental 4 lb ai/ acre 1 48234 15 1 RegalStar II G landscape: woody ornamentals shrubs, trees, vines 2 lb ai/ acre 1 48234 15 1 RegalStar II G nursery: woody ornamentals shrubs, trees, vines 2 lb ai/ acre 1 48234 15 1 RegalStar II G turf: golf course 2 lb ai/ acre 1 48234 15 1 RegalStar II G turf: sod farms 2 lb ai/ acre 1 48234 2 2 Regal Ronstar Plus G landscape: woody ornamental shrubs, vines and trees 4 lb ai/ acre 1 48234 2 2 Regal Ronstar Plus G nursery: conifer 4 lb ai/ acre 1 48234 2 2 Regal Ronstar Plus G nursery: woody ornamental shrubs, vines and trees 4 lb ai/ acre 3 48234 2 2 Regal Ronstar Plus G turf: golf course 4 lb ai/ acre 1 48234 2 2 Regal Ronstar Plus G turf: ornamental ( parks) 4 lb ai/ acre 1 52287 1 0.95 Harrells Crabgrass Control with Ronstar G turf: golf course 4 lb ai/ acre 3 52287 1 0.95 Harrells Crabgrass Control with Ronstar G turf: ornamental 4 lb ai/ acre 3 52287 2 1.5 Harrells Ronstar 1.5 G turf: golf course 4 lb ai/ acre 3 52287 2 1.5 Harrells Ronstar 1.5 G turf: ornamental 4 lb ai/ acre 3 52287 3 0.67 Harrells Ronstar 0.67 with Fertilizer G turf: golf course 4 lb ai/ acre 3 52287 3 0.67 Harrells Ronstar 0.67 with FertilizerG turf: ornamental 4 lb ai/ acre 3 538 164 1.31 Scotts ProTurf Goosegrass/ Crabgrass Control 8656 turf: golf course ( fairways and greens) 0.75 538 164 1.31 Scotts ProTurf Goosegrass/ Crabgrass Control 8656 turf: golf course ( fairways and tees) 1.5 538 164 1.31 Scotts ProTurf Goosegrass/ Crabgrass Control 8656G turf: golf course ( greens) 1.5 538 164 1.31 Scotts ProTurf Goosegrass/ Crabgrass Control 8656 turf: ornamental 0.75 538 241 ~ 1 Scotts Turf Starter Plus G turf: golf course fairways 4 lb ai/ acre 1 538 241 ~ 1 Scotts Turf Starter Plus G turf: ornamental 4 lb ai/ acre 1 538 257 0.2 Scotts  ProTurf Fertilizer Plus Preemergent Weed Control II turf: golf course 4 lb ai/ acre 2 538 257 0.2 Scotts  ProTurf Fertilizer Plus Preemergent Weed Control II turf: ornamental 4 lb ai/ acre 2 55615 4 0.75 Wilbro Fertilizer with 0.75% Ronstar G turf: golf course 4 lb ai/ acre 1 55615 4 0.75 Wilbro Fertilizer with 0.75% Ronstar G turf: ornamental 4 lb ai/ acre 1 557 1966 0.69 ParEx Plus Ronstar G turf: golf course 4 lb ai/ acre 1 557 1966 0.69 ParEx Plus Ronstar G turf: ornamental ( parks) 4 lb ai/ acre 1 557 1974 1.5 ParEx Fertilizer Plus 1.5% RonstarG turf: golf course ( fairways) 4 lb ai/ acre 1 557 1974 1.5 ParEx Fertilizer Plus 1.5% Ronstar G turf: lawns ( but not home lawns) 4 lb ai/ acre 1 557 1974 1.5 ParEx Fertilizer Plus 1.5% Ronstar G turf: ornamental ( parks) 4 lb ai/ acre 1 557 2026 1 ParEx Fertilizer Plus 1% Ronstar G turf: golf course 4 lb ai/ acre 1 557 2026 1 ParEx Fertilizer Plus 1% Ronstar G turf: lawns 4 lb ai/ acre 1 10 557 2026 1 ParEx Fertilizer Plus 1% Ronstar G turf: ornamental 4 lb ai/ acre 1 67508 1 1 Ronstar 1% with Fertilizer G turf: golf course 4 lb ai/ acre 1 67508 1 1 Ronstar 1% with Fertilizer G turf: ornamental 4 lb ai/ acre 1 8660 17 1 Sta Green G turf: golf course 2.5 1 8660 17 1 Sta Green G turf: lawns 2.5 1 8660 36 1 Vertagreen Fertilizer with Ronstar G turf: golf course 4 lb ai/ acre 3 8660 36 1 Vertagreen Fertilizer with Ronstar G turf: ornamental 4 lb ai/ acre 3 9198 154 1 Andersons Fertilizer with 1% Ronstar and 0.125% Dimension G turf: golf course ( fairways and roughs) 4 lb ai/ acre 3 9198 154 1 Andersons Fertilizer with 0.125% Dimension and 1.0% Ronstar G turf: golf course ( fairways) 2 lb ai/ acre 3 9198 154 1 Andersons Fertilizer with 0.125% Dimension and 1.0% Ronstar G turf: golf course ( roughs) 1.5 3 9198 154 1 Andersons Fertilizer with 1% Ronstar and 0.125% Dimension G turf: lawns 4 lb ai/ acre 3 9198 154 1 Andersons Fertilizer with 1% Ronstar and 0.125% Dimension G turf: ornamental 4 lb ai/ acre 3 9198 75 1.38 Andersons Fertilizer with 1.38% Ronstar G turf: golf course ( fairways, tees) 4 lb ai/ acre 9198 75 1.38 Andersons Fertilizer with 1.38% Ronstar G turf: golf course( fairways and tees) 4 lb ai/ acre 9198 75 1.38 Andersons Fertilizer with 1.38% Ronstar G turf: lawns 4 lb ai/ acre 9198 75 1.38 Andersons Fertilizer with 1.38% Ronstar G turf: ornamental 4 lb ai/ acre 9198 75 1.38 Andersons Fertilizer with 1.38% Ronstar G turf: ornamental 4 lb ai/ acre 961 340 1.73 Lebanon Country Club with Ronstar G landscape: woody ornamentals, shrubs, vines 4 lb ai/ acre 3 961 340 1.73 Lebanon Country Club with Ronstar G nursery: conifer 4 lb ai/ acre 3 961 340 1.73 Lebanon Country Club with Ronstar G nursery: woody ornamentals shrubs, trees, vines 4 lb ai/ acre 3 961 340 1.73 Lebanon Country Club with Ronstar G turf: golf course 4 lb ai/ acre 1 961 340 1.73 Lebanon Country Club with Ronstar G turf: ornamental ( parks and gardens) 4 lb ai/ acre 1 961 371 0.5 Lebanon Country Club with Ronstar G turf: golf course 4 lb ai/ acre 961 371 0.5 Lebanon Country Club with Ronstar G turf: ornamental 4 lb ai/ acre CA 970018 50 Chipco Ronstar 50 WSP landscape: specific ornamental crops 3 lb ai/ acre NS CA 970018 50 Chipco Ronstar 50 WSP nursery: specific ornamental crops 3 lb ai/ acre NS FL 820045 2 Chipco Ronstar G leatherleaf ferns 2 lb ai/ acre NS HI 970001 2 Chipco Ronstar G turf: Lalo 3 lb ai/ acre 1 1.3 Methods and Types of Equipment Used for Mixing/ Loading/ Applying The following use patterns are associated with the application equipment: chemigation, groundboom, rights of way sprayer, handgun sprayer, tractor drawn spreader, backpack sprayer, low pressure handwand, high pressure handwand lawn handgun, belly grinder and push type spreader. ( aerial application was voluntarily canceled by the registrant)

1.4 Incident reports The following data bases have been consulted for the poisoning incident data on the active ingredient oxadiazon3.

I. Incident Data System Please note that the following cases from the IDS do not have documentation confirming exposure or health effects unless otherwise noted.

Incident# 6920 2 A pesticide incident occurred in 1998, when a man applied oxadiazon on a wet lawn. He reported nausea, headache, and difficulty breathing. No further information on the disposition of the case was reported.

Incident# 7424 1 11 A pesticide incident occurred in 1998, when oxadiazon was sprayed onto landscaping at a large apartment complex. Several individuals reported congestion, sore throat, running eyes, and hoarseness. No further information on the disposition of the case was reported.

Incident# 8383 1 A pesticide incident occurred in 1998, when a man used oxadiazon for two weeks on the landscape of several properties. He reported hives over his entire body area, itching, and a swollen face. He experienced a rash that lasted for twenty four hours. However, these effects only occurred on the last two days of use and may, instead, be a reaction to ibuprofen. He was seen by a physician. No further information on the disposition of the case was reported.

Incident# 8383 2 A pesticide incident occurred in 1997, when an unknown person applied the product to grass around a home. A year and a half later, a man who has chronic fatigue syndrome, reported malaise. He now lives with his brother and reports developing acute symptoms whenever he returns to his home. No further information on the disposition of the case was reported.

Incident# 8476 1 A pesticide incident occurred in 1999, when a golf course was treated. Several months later, a female employee reported respiratory irritation and muscle weakness. No further information on the disposition of the case was reported.

Incident# 9413 1 A pesticide incident occurred in 1999, when a man mixed the product in his home and reported a seizure the next morning. Two days later he poured the chemical into a spreader and ten minutes later reported a seizure. This individual has a history of ongoing seizure and is taking medication for his condition. Physicians treating this case did not believe that the seizure were related to the pesticide exposure. No further information on the disposition of the case was reported.

Incident# 10179 10 A pesticide incident occurred in 1996, when a teacher and his daughter reported headaches, dizziness, burning eyes and skin, coughing, sore throat and hoarseness after oxadiazon was applied to a school campus. No further information on the disposition of the case was reported. This same case is reported in the California data summary.

No consistent pattern of ill effects was seen in this relatively small number of incidents. There was some evidence of irritative and allergic effects to the skin and respiratory system.

II. Poison Control Center Data  1993 through 1998 Results for the years 1993 through 1998 were acquired for 37 exposures to oxadiazon reported to Poison Control Centers. Cases involving exposures to multiple products are 12 excluded. Only 4 cases were reported among children under six years of age and six cases among older children and adults exposed at their workplace. This was too few cases to warrant detailed analysis. None of these cases reported a serious outcome and only one of the occupational cases had a moderate outcome. There were 27 non occupationally exposed cases among older children and adults.

III. California Data  1982 through 1996 Detailed descriptions of 31 cases submitted to the California Pesticide Illness Surveillance Program ( 1982 1996) were reviewed. In 26 of these cases, oxadiazon was used alone or was judged to be responsible for the health effects. Only cases with a definite, probable or possible relationship were reviewed. Oxadiazon ranked 84th as a cause of systemic poisoning in California based on data for 1982 through 1994. Category includes cases where skin, eye, or respiratory effects were also reported.

IV. National Pesticide Telecommunications Network On the list of the top 200 chemicals for which NPTN received calls from 1984 1991 inclusively, oxadiazon was ranked 192nd with 12 incidents in humans reported and 5 incidents in animals ( mostly pets).

2.0 OCCUPATIONAL EXPOSURES 2.1 Handler Exposures & Assumptions iii. Handler Exposure Scenarios Exposure scenarios can be thought of as ways of categorizing the kinds of exposures that occur related to the use of a chemical. The use of scenarios as a basis for the exposure assessment is described in the U. S. EPA Guidelines For Exposure Assessment ( U. S. EPA; Federal Register Volume 57, Number 104; May 29, 1992).

HED uses the term " Handlers" to describe those individuals who are involved in the pesticide application process. HED believes that there are distinct job functions or tasks related to applications and that exposures can vary depending on the specifics of each task. Job requirements ( e. g., amount of chemical to be used in an application), the kinds of equipment used, the crop or target being treated, and the circumstances of the user ( e. g., the level of protection used by an applicator) can cause exposure levels to differ in a manner specific to each scenario.

HED has developed a series of general descriptions for tasks that are associated with pesticide applications. Tasks associated with pesticide use ( i. e., for " handlers") can generally be categorized using one of the following terms: 13

Occupational Mixer/ loaders: these individuals perform tasks in preparation for an application. For example, they would prepare dilute spray solutions and/ or load/ transfer solid materials ( e. g., granulars) or dilute spray solutions into application equipment such as a groundboom tractor or planter prior to application.

Occupational Applicators: these individuals operate application equipment during the application of oxadiazon to registered sites. These individuals can make applications using equipment such as groundboom sprayers or tractor drawn spreaders for granular materials.

Occupational Mixer/ loader/ applicators: these individuals are involved in the entire pesticide application process ( i. e., they do all job functions related to a pesticide application event). These individuals would prepare a dilute spray solution and then also apply the solution. HED always considers some exposures to be mixer/ loader/ applicator exposures because of the equipment used and the logistics associated with such applications. For example, if one uses a small handheld device such as a 1 gallon low pressure handwand sprayer it is anticipated that one individual will mix a spray solution and then apply the solution because of labor and logistical considerations.

HED has determined that there are potential exposures to mixers, loaders, applicators, or other handlers during usual use patterns associated with oxadiazon. Based on the use patterns and potential exposures described above, 14 major exposure scenarios are identified in this document to represent the extent of oxadiazon uses. These scenarios include: mixing/ loading wettable powders for chemigation application ( 1a), mixing/ loading wettable powders for groundboom application ( 1b), mixing/ loading wettable powders for rights of way sprayer ( 1c), loading granular formulations ( 2), applying with a groundboom ( 3), applying with a rights of way sprayer ( 4), applying wettable powders for handgun applicators ( ORETF) ( 5), applying granular with a tractor drawn spreader ( 6), backpack sprayer ( LCO) ( 7), low pressure handwand wettable powder formulations ( LCO) ( 8), high pressure handwand  ( wettable powder formulations) ( 9), lawn handgun ( wettable powder formulations) ( ORETF) ( 10), granulars with a push type spreader ( ORETF) ( 11), granulars with a bellygrinder ( LCO) ( 12).

In most cases, HED assesses the exposure and risk to mixer/ loaders and applicators separately for tractor drawn applications ( i. e. granular spreaders) in the RED chapter. This practice has evolved, not because it is believed that there are always separate job functions, but rather because of the limited amount of information regarding these practices along with limited exposure data. For occupational RED chapters process, HED has adopted a methodology to present the risks separately for some scenarios and combine others. Most of the hand held equipment such as backpack sprayers, and push type granular spreaders are assessed as a combined function. With these types of small operations the mixing, loading, and applying are almost always carried out by the same individual and there are data available to estimate exposure from these activities. 14 For equipment such as groundboom tractors, the applications is assessed separately from the individual who mixes and loads the formulated product. By separating the two job functions, HED can determine the most appropriate PPE or engineering control without requiring the handler to wear PPE throughout the entire workday or engineering controls that are not needed.

2.1.1 Summary of Occupational Handler Exposures Table 4 presents the exposure scenarios, application rates, and area ( i. e., acres ) potentially treated that have been used in the exposure calculations. Oxadiazon labels include a multitude of uses and a range of application rates.

Chemical specific data for assessing human exposures during pesticide handling activities were not submitted to the Agency in support of the reregistration of oxadiazon. Consequently it is the policy of the HED to use data from the Pesticide Handlers Exposure Database ( PHED) 4 Version 1.1 to assess handler exposures for regulatory actions when chemical specific monitoring data are not available.

PHED was designed by a task force of representatives from the U. S. EPA, Health Canada, the California Department of Pesticide regulation, and member companies of the American Crop Protection Association. PHED is a software system consisting of two parts  a database of measured exposure values for workers involved in the handling of pesticides under actual field conditions and a set of computer algorithms used to subset and statistically summarize the selected data. Currently, the database contains values for over 1,700 monitored individuals ( i. e., replicates)

Users select criteria to subset the PHED database to reflect the exposure scenario being evaluated. The subsetting algorithms in PHED are based on the central assumption that the magnitude of handler exposures to pesticides are primarily a function of activity ( e. g., mixing/ loading, applying), formulation type ( e. g., wettable powders, granulars), application method ( e. g., groundboom), and clothing scenarios ( e. g., gloves, double layer clothing).

Once the data for a given exposure scenario have been selected, the data are normalized ( i. e., divided by) by the amount of pesticide handled resulting in standard unit exposures ( milligrams of exposure per pound of active ingredient handled). Following normalization, the data are statistically summarized. The distribution of exposure values for each body part ( e. g., chest upper arm) is categorized as normal, lognormal, or " other" ( i. e., neither normal nor lognormal). A central tendency value is then selected from the distribution of the exposure values for each body part. These values are the arithmetic mean for normal distributions, the geometric mean for lognormal distributions, and the median for all " other" distributions. Once selected, the central tendency values for each body part are composited into a " best fit" exposure value representing the entire body.

The unit exposure values calculated by PHED generally range from the geometric mean to 15 the median of the selected data set. To add consistency and quality control to the values produced from this system, the PHED Task Force has evaluated all data within the system and has developed a set of grading criteria to characterize the quality of the original study data. The assessment of data quality is based on the number of observations and the available quality control data. These evaluation criteria and the caveats specific to each exposure scenario are summarized in TableA4. While data from PHED provide the best available information on handler exposures, it should be noted that some aspects of the included studies ( e. g., duration, acres treated, pounds of active ingredient handled) may not accurately represent labeled uses in all cases. HED has developed a series of tables of standard unit exposure values for many occupational scenarios that can be utilized to ensure consistency in exposure assessments.

The method of risk assessment for adult non occupational/ residential handlers was essentially the same as that for occupational workers with similar application methods. The Residential SOPs ( 1997) and the Outdoor Residential Exposure Task Force ( ORETF ) study data were both used to estimate exposure and compared. After preliminary review by the Agency, the ORETF data was found to be equal or superior in quality to the data set from the Standard Operating Procedures ( SOPs) for Residential Exposure Assessments ( revised December 1999) currently used by the Agency. Some of these data may be combined, but they are used separately for this assessment.

Table 4: Exposure Variables for Uses ofOxadiazon Exposure Scenario ( Scenario #) Crop Type Application Rates ( lb ai/ acre) a Daily Acres Treatedb Mixer/ Loader Exposure Mixing/ Loading Wettable Powders for Chemigation Application ( 1a) sod farms 3 350 Mixing/ Loading Wettable Powders for Groundboom Application ( 1b) conifer nurseries, woody ornamentals 4 40 herbaceous ornamentals 3 40 sod farms 3 80 golf courses 4 40 Mixing/ Loading Wettable Powders for Rights of Way Sprayer ( 1c) roadside turf, ornamentals 4 40 Loading Granular formulations ( 2) sod farms, conifers forest. 4 80 golf course turf, parks, recreational areas 4 40 woody ornamentals 4 40 Applicator Table 4: Exposure Variables for Uses ofOxadiazon Exposure Scenario ( Scenario #) Crop Type Application Rates ( lb ai/ acre) a Daily Acres Treatedb 16 Applying with a Groundboom ( 3) sod farms 3 80 herbaceous ornamentals 3 40 golf courses 4 40 conifer nurseries, woody ornamentals 4 40 Applying with a Rights of Way Sprayer ( 4) roadsides 4 40 Applying Wettable Powders for Handgun Applicators ( ORETF) ( 5) lawns, parks, recreational areas 4 5 Applying Granular with a Tractor Drawn Spreader ( 6) sod farms 4 80 golf courses 4 40 Mixer/ Loader/ Applicator Backpack Sprayer ( LCO) ( 7) l a w n s , g o l f c o u r s e s , ornamentals nurseries 4 5 Low Pressure Handwand  Wettable Powder Formulations ( LCO) ( 8) lawns, golf courses, nursery stock 4 5 High Pressure Handwand  ( Wettable Powder Formulations) ( 9) woody ornamentals, conifer nurseries. 4 5 Lawn Handgun ( Wettable Powder Formulations) ( ORETF) ( 10) ornamentals, lawns, parks rec areas 4 5 Granulars with a Push Type Spreader ( ORETF) ( 11) lawns, golf courses, parks, r e c r e a t i o n a l a r e a s , ornamentals 4 5 Granulars with a Bellygrinder ( LCO) ( 12) golf courses, parks, rec areas. 4 1 a Application rates are the maximum or range found on oxadiazon labels b Daily acres treated are based on HED's estimates of acreage that would be reasonably expected to be treated in a single day for each exposure scenario of concern. LCO = lawn care operators 2.1.2 Summary of Uncertainties The handler exposure assessments encompass all of the major uses of oxadiazon throughout the country. It is difficult to assess all of the " typical" uses ( i. e., actual or predominate application rates and farm sizes), and therefore, an assessment has been developed that is believed to be realistic and yet provides a reasonable certainty that the exposures are not underestimated. 17 Daily Dermal Exposure mg ai Day

Dermal Unit Exposure mg ai lb ai

Max. Appl. Rate lb ai Acre

Max. Area Treated Acres Day Daily Inhalation Exposure mg ai day

Unit Exposure

g ai lb ai x Conversion Factor 1mg 1,000

g x Use Rate lb ai A x Daily Acres Treated A day The assumptions and uncertainties are identified below to be used in risk management decisions:

Application Rates: The application rates are the maximum allowable that were identified on the available product labels.

Amount Handled: The daily acres treated are HED standard values ( see Table 4). The values for groundboom applications in agriculture and on turf/ ornamentals vary. Groundboom applications in an agricultural setting are based on an 80 acre day because the Agency believes it would take 8 hours to complete that type of application with common equipment and that acreage estimate for various crops is reasonable. On the other hand, the value for groundboom applications on golfcourse turf is based on treating 40 acres because that is the value calculated to represent a 18 hole course ( they account for about 10% of all golf courses based on registrants comments and investigation by Agency personnel). The 40 acre value is not the maximum that can be treated on a single day given that the application equipment is likely capable of treating higher acreage. The daily limitation of 40 acres per day is based on the fact that an applicator would only treat a course a single time on any given day.

2.1.3 Calculations of Exposure Potential daily dermal exposure is calculated using the following formula:

Potential daily inhalation exposure is calculated using the following formula:

These calculations of potential daily exposure to oxadiazon by handlers are used to calculate the absorbed doses and total risk to those handlers ( see Occupational Risk section).

2.1.4 Calculation of Cancer Cancer risk assessments for handler used baseline exposure scenarios and, as needed, increasing levels of risk mitigation ( PPE and engineering controls) to achieve cancer risks that are not of concern. Tables B1 to B4 in Appendix B present total cancer risk calculations at baseline, with various PPE ( ie., single layer+ gloves and no respirator, double layer + gloves and no 18 Daily Dermal Exposure mg ai day

Unit Exposure mg ai lb ai x Use Rate lb ai A x Daily Acres Treated A day Daily Inhalation Exposure mg ai day

Unit Exposure

g ai lb ai x Conversion Factor 1mg 1,000

g x Use Rate lb ai A x Daily Acres Treated A day Daily Inhalation Dose mg ai kg/ day

Daily Inhalation Exposure mg ai day x 1 Body Weight ( kg)

Daily Dermal Dose mg ai Kg/ Day

Daily Dermal Exposure mg ai Day x 1 Body Weight ( Kg) x 0.09 Dermal Absorption Factor Total Daily Dose

Daily Dermal Dose mg kg/ day  Daily Inhalation Dose mg kg/ day LADD mg kg/ day

Daily Total Dose mg kg/ day x days worked 365 days per year x 35 years worked 70 year lifetime respirator, single layer+ gloves and respirator and double layer + gloves and respirator) and with engineering controls, respectively, for each exposure scenario.

The calculations of daily dermal and inhalation exposure to oxadiazon by handlers were used to calculate the daily dose, and hence the risks, to those handlers. Potential daily dermal exposure was calculated using the following formula:

Potential daily inhalation exposure was calculated using the following formula:

The daily dermal and inhalation doses were calculated using a 70 kg body weight using the following formulas:

The lifetime average daily dose ( LADD) was calculated using the following formula:

T otal cancer risk was calculated using the following formula: 19 Total Cancer Risk

LADD x Q1  where Q 1 * = 7.11x10 2 ( mg/ kg/ day) 1 The following assumptions and factors were used in order to complete this cancer risk assessment:

The average body weight of 70 kg is used, representing a typical adult.

Career duration is assumed to be 35 years. This represents a typical working lifetime.

Lifetime is assumed to be 70 years.

Dermal absorption is assumed to be 9 %, and inhalation absorption is assumed to be 100 percent of the oral dose. The dermal and inhalation doses were added together to represent total daily dose.

The Q1* used in the cancer assessment was 7.11x10 2( mg/ kg/ day) 1 .

Two exposure frequencies were used in the calculations, the first represented the maximum number of applications per site per season to represent private use ( 3), and the second frequency applied a factor of ten to the first frequency to represent commercial handlers making multiple applications per site per season ( 30).

The Agency has defined a range of acceptable cancer risks based on a policy memorandum issued in 1996 by then office director, Dan Barolo. This memo refers to a predetermined quantified " level of concern" for occupational carcinogenic risk. In summary, this policy memo indicates occupational carcinogenic risks that are 1 x 10 6 or lower require no risk management action. For those chemicals subject to reregistration, the Agency is to carefully examine uses with estimated risks in the 10 6 to 10 4 range to seek ways of cost effectively reducing risks. If carcinogenic risks are in this range for occupational handlers, increased levels of personal protection would be warranted as is commonly applied with noncancer risk estimates ( e. g., additional PPE or engineering controls). Carcinogenic risks that remain above 1.0 x 10 4 at the highest level of mitigation appropriate for that scenario remain a concern.

2.2 Risk From Handler Exposures Using the daily dermal exposure scenarios identified in the exposure section, EPA calculated the potential risk to persons from handler exposures and post application exposures to oxadiazon. 20 Daily Inhalation Dose mg ai kg/ day

Daily Inhalation Exposure mg ai day x 1 Body Weight ( kg)  1 ( 100%)

Daily Dermal Dose mg ai kg/ Day

Daily Dermal Exposure mg ai Day x 1 Body Weight ( kg)  0.09 ( 9%)

MOE

NOAEL mg kg/ day Dermal Daily Dose mg kg/ day MOE

NOAEL mg kg/ day Inhlation Daily Dose mg kg/ day Potential dermal and inhalation daily exposures for occupational handlers were calculated using the following formulas ( 9% dermal absorption was assumed):

The daily dermal and inhalation doses were calculated using a 60 kg body weight using the following formulas:

The MOEs were calculated using the following formulas:

A total MOE is also calculated because there is a common endpoint. The uncertainty factor of 100 is applied to all routes and exposure durations. Route specific data are available for the dermal and oral routes, and therefore, the following reciprocal MOE calculation is used:

1/(( 1/ Dermal MOE) + ( 1/ Inhalation MOE)

2.2.1 Risk From Handler Exposures Handler exposure assessments are completed by EPA using a baseline exposure scenario and, if required, increasing levels of risk mitigation ( PPE and engineering controls) to achieve a margin of exposure of 100 for dermal and inhalation exposure or cancer risk of 1.0x 10 4 to 1.0x 10 6. Appendix A presents the short term and intermediate term MOE calculations for baseline exposure plus the risk mitigation measures of personal protective equipment ( PPE) and engineering controls using data from PHED and ORTEF for the uses of oxadiazon. Aventis is a member of the ORETF so there are no data compensation issues associated with the use of this data. Appendix B Tables B1 to B4 presents the cancer risk calculations for baseline exposure plus the risk mitigation measures of personal protective equipment ( PPE) and engineering 21 controls.

EPA calculated the baseline MOE ( short term and intermediate term) and cancer for each of the exposure scenarios using the following baseline PPE assumptions:

$ all occupational handlers are wearing footwear ( socks plus shoes or boots).

$ occupational mixers and loaders using open mixing techniques are wearing longsleeved shirts, long pants, and no gloves.

$ occupational applicators use open cab tractor driven application equipment.

$ occupational handlers ( mixers, loaders, and applicators) who use hand held application equipment are wearing long sleeve shirts, long pants, and no gloves.

If the baseline short term or intermediate term MOE calculated using this baseline PPE was 100 or greater ( since the NOAEL is based on data from animal studies) for an exposure scenario, then no further calculations were made. If the baseline short term or intermediate term MOE was less than 100 for any exposure scenario, an additional short term or intermediate term MOE was calculated based on increasing the level of PPE over the baseline PPE. HED calculated the additional PPE short term or intermediate term MOE for each occupational exposure scenario with a baseline total MOE of less than 100, using the following additional PPE assumptions:

$ all occupational handlers are wearing footwear ( socks plus shoes or boots)

$ occupational mixers and loaders using open mixing techniques are wearing longsleeved shirts and long pants and gloves; this represents minimum PPE $ occupational mixers and loaders using open mixing techniques are wearing longsleeved shirts and long pants, coveralls and gloves; this represents maximum PPE $ occupational applicators who use open cab tractor driven application equipment $ Also, if necessary, dust/ mist respirator represented by 5 fold protection factor or an organic vapor respirator represented by a 10 fold protection factor are added to mitigate the risks.

If the additional PPE short term or intermediate term MOE calculated using this additional PPE was 100 or greater ( the NOAEL is based on data from animal studies) for an exposure scenario, then no further calculations were made. If the additional PPE short term or intermediate term MOE remained less than 100 for any occupational exposure scenario, an addition short term or intermediate term MOE was calculated based on mandatory use of engineering controls where feasible. Engineering controls are not available for occupational handlers ( mixers, loaders, and applicators) who use hand held application equipment. HED calculated the engineering control short term or intermediate term MOE for each occupational exposure scenario with an additional PPE short term or intermediate term MOE of less than 100, using the following engineering control assumptions:

$ all occupational handlers are wearing footwear ( socks plus shoes or boots).

$ occupational mixers and loaders handling liquid formulations using a closed system 22 are wearing chemical resistant gloves plus long sleeved shirts and long pants.

$ occupational mixers and loaders handling wettable powders using a closed system ( water soluble packages) are wearing long sleeved shirts and long pants, and chemical resistant gloves.

$ occupational applicators who use tractor driven application equipment are located in enclosed cabs are wearing long sleeved shirts and long pants, and no gloves.

2.2.2 Summary of Handler MOEs and Cancer Table 5 summarizes the numeric MOE values for both the short and intermediate term exposure durations. The MOEs are presented for baseline, PPE and engineering controls. Cancer values also summarized in Table 6 at different levels of mitigation. Baseline for non cancer assessment represents long pants, long sleeved shirts and no gloves or respirator, PPE dermal unit exposure represents long pants, long shirts and gloves for scenarios 5, 7, 9 and long pants, long shirts gloves and double layer ( 50% protection) for scenarios 1a, 1b, 1c, and 8. PPE inhalation unit exposure represents dust/ mist respirator ( 80 % protection) for scenarios 1a, 1b, 1c, and 8.

Engineering Control dermal unit exposure scenarios includes long pants, long shirts, gloves and water soluble packages for scenario 1a.

The results of the short and intermediate term handler assessments indicate that all potential exposure scenarios provide at least one application rate with a total MOE( s) greater than or equal to 100 at either the baseline ( i. e., long pants, long sleeved shirts, no gloves) using open systems, PPE ( i. e., long pants, long sleeved shirts, and chemical resistant gloves while using open systems) or using engineering controls ( i. e., closed systems). In the majority of cases, it is dermal exposure rather than the inhalation exposure driving the total MOEs. In total, 37 MOEs were calculated for the various application rates. The total MOEs for all the scenarios range from 2 to 3000.

The results of the Cancer Risk indicate that the values range from 1.65E 2 to 4.66E 7 at the baseline ( long pants, long shirts and no gloves), 2.56E 3 to 4.11E 7 at PPE1 ( long pants, long shirts, gloves and no respirator), 2.40E 3 at PPE2 ( long pants, long shirts, double layer, gloves and no respirator), 1.05E 3 to 1.98E 7 at PPE3 ( long pants, long shirts, gloves and respirator), 8.90E 4 to 1.38E 07 at PPE4 ( long pants, long shirts, double layer, gloves and respirator) and 9.92E 5 to 1.10E 8 at engineering control.

Table 5: Exposure Variables, MOEs for Uses of Oxadiazon Exposure Scenario ( Scenario #) Crop Type App Rates ( lb ai/ acre) Daily Acres Treated Dermal MOEs Inhalation MOEs Base line PPE Eng. Control Base line PPE En Con Mixer/ Loader Table 5: Exposure Variables, MOEs for Uses of Oxadiazon Exposure Scenario ( Scenario #) Crop Type App Rates ( lb ai/ acre) Daily Acres Treated Dermal MOEs Inhalation MOEs Total MOEs Base line PPE Eng. Control Base line PPE Eng. Control Base line PPE Eng. Control 23 Mixing/ Loading Wettable Powders for Chemigation Application ( 1a) sod farms 3 350 2 59 gl, dl 780 wsp 16 80 resp 2900 2 35 610 Mixing/ Loading Wettable Powders for Groundboom Application ( 1b) conifer nurseries, woody ornamentals 4 40 14 380 gl, dl NA 100 520 resp NA 12 220 NA herbaceous ornamentals 3 40 18 510 gl, dl NA 140 700 resp NA 16 300 NA sod farms 3 80 9 260 gl, dl NA 70 350 resp NA 8 150 NA golf courses 4 40 14 380 gl, dl NA 100 520 resp NA 12 220 NA Mixing/ Loading Wettable Powders for Rights of Way Sprayer ( 1c) r o a d s i d e t u r f ,

ornamentals 4 40 14 380 gl, dl NA 100 520 resp NA 12 220 NA Loading Granular formulations ( 2) so d f a rms , coni fer s forest 4 80 3000 NA NA 1300 NA NA 920 NA NA golf course turf, parks,

recreational areas 4 40 6000 NA NA 2600 NA NA 1800 NA NA woody ornamentals 4 40 6000 NA NA 2600 NA NA 1800 NA NA Applicator Applying with a Groundboom ( 3) sod farms 3 80 2400 NA NA 4100 NA NA 1500 NA NA herbaceous ornamentals 3 40 4800 NA NA 8100 NA NA 3000 NA NA golf courses 40 3600 NA NA 6100 NA NA 2300 NA NA conifer nurseries, woody ornamentals 4 40 3600 NA NA 6100 NA NA 2300 NA NA Applying with a Rights of Way Sprayer ( 4) roadsides 4 40 38 130 NA 1200 1200 NA 37 120 NA Applying Wettable Powders for Handgun Applicators ( ORETF) ( 5) l a w n s , p a r k s ,

recreational areas 4 5 See PPE 550 gl NA 36000 36000 NA See PPE 540 NA Table 5: Exposure Variables, MOEs for Uses of Oxadiazon Exposure Scenario ( Scenario #) Crop Type App Rates ( lb ai/ acre) Daily Acres Treated Dermal MOEs Inhalation MOEs Total MOEs Base line PPE Eng. Control Base line PPE Eng. Control Base line PPE Eng. Control 24 Applying Granular with a Tractor Drawn Spreader ( 6) sod farms 4 80 2500 NA NA 1900 NA NA 1100 NA NA golf courses 4 40 5100 NA NA 3800 NA NA 2200 NA NA Mixer/ Loader/ Applicator Backpack Sprayer ( LCO) ( 7) l awns, gol f courses,

ornamentals nurseries 4 5 See PPE 160 gl NA 1200 1200 NA See PPE 140 NA Low Pressure Handwand

Wettable Powder Formulations ( LCO) ( 8) lawns, golf courses,

nursery stock 4 5 14 65 gl, dl NF 33 160 resp NF 10 46 NF High Pressure Handwand

( Wettable Powder Formulations)

( 9) woody ornamentals,

conifer nurseries. 4 5 See PPE 160 gl NA 300 300 NA See PPE 100 NA Lawn Handgun ( Wettable Powder Formulations) ( ORETF) ( 10) ornamentals, lawns,

parks rec areas 4 5 560 NA NA 580 NA NA 280 NA NA Granulars with a Push Type Spreader ( ORETF) ( 11) lawns, golf courses,

parks, recreational areas,

ornamentals 4 5 1100 NA NA 4800000 NA NA 1100 NA NA Granulars with a Bellygrinder ( LCO) ( 12) golf courses, parks, rec areas. 4 1 200 NA NA 2900 NA NA 190 NA NA Baseline dermal unit exposure scenarios includes long pants, long shirts and no gloves. .

Baseline inhalation unit exposure represents no respirator PPE dermal unit exposure includes long pants, long shirts and gloves for scenarios5, 7, and 9.

PPE dermal unit exposure includes long pants, long shirts gloves and double layer ( 50% protection) for scenarios 1a, 1b, 1c, and 8.

PPE inhalation unit exposure represents dust/ mist respirator ( 80 % protection) for scenarios 1a, 1b, 1c, and 8.

Engineering Control dermal unit exposure scenarios includes long pants, long shirts, gloves and water soluble packages for scenario 1a.

Engineering inhalation unit exposure represents no respirator NA = Not applicable NF= not feasible gl = gloves dl = double layer wsp = water soluble packages resp = dust mist respirator 25 Table 6: Exposure Variables, Cancer for Uses of Oxadiazon Exposure Scenario ( Scenario #) Crop/ Target Appl Rates ( lb ai/ acre) Daily Acres Treated Cancer Base line PPE 1 PPE 2 PPE 3 PPE 4 Eng. Control Mixer/ Loader Mixing/ Loading Wettable Powders for Chemigation Application ( 1a) sod farms 3 350 1.65e 03/

1.65e 02 2.56e 04/

2.56e 03 2.40e 04/

2.40e 03 1.05e 04/

1.05e 03 8.90e 05/

8.90e 04 4.92e 06/

4.92e 05 Mixing/ Loading Wettable Powders for Groundboom Application ( 1b) conifer nurseries, woody ornamentals 4 40 2.51e 04/

2.51e 03 3.89e 05/

3.89e 04 3.65e 05/

3.65e 04 1.60e 05/

1.60e 04 1.36e 05/

1.36e 04 7.49e 07/

7.49e 06 herbaceous ornamentals 3 40 1.88e 04/

1.88e 03 2.92e 05/

2.92e 04 2.74e 05/

2.74e 04 1.20e 05/

1.20e 04 1.02e 05/

1.02e 04 5.62e 07/

5.62e 06 sod farms 3 80 3.77e 04/

3.77e 03 5.84e 05/

5.84e 04 5.48e 05/

5.48e 04 2.39e 05/

2.39e 04 2.03e 05/

2.03e 04 1.12e 06/

1.12e 05 golf courses 4 40 2.51e 04/

2.51e 03 3.89e 05/

3.89e 04 3.65e 05/

3.65e 04 1.60e 05/

1.60e 04 1.36e 05/

1.36e 04 7.49e 07/

7.49e 06 Mixing/ Loading Wettable Powders for Rights of Way Sprayer ( 1c) roadside turf, ornamentals 4 40 2.51e 04/

2.51e 03 3.89e 05/

3.89e 04 3.65e 05/

3.65e 04 1.60e 05/

1.60e 04 1.36e 05/

1.36e 04 7.49e 07/

7.49e 06 Loading Granular formulations ( 2) sod farms, conifers forest 4 80 3.28e 06/

3.28e 05 3.10e 06/

3.10e 05 2.68e 06/

2.68e 05 1.28e 06/

1.28e 05 8.63e 07/

8.63e 06 2.20e 08/

2.20e 07 golf course turf, parks,

recreational areas 4 40 1.64e 06/

1.64e 05 1.55e 06/

1.55e 05 1.34e 06/

1.34e 05 6.42e 07/

6.42e 06 4.31e 07/

4.31e 06 1.10e 08/

1.10e 07 woody ornamentals 4 40 1.64e 06/

1.64e 05 1.55e 06/

1.55e 05 1.34e 06/

1.34e 05 6.42e 07/

6.42e 06 4.31e 07/

4.31e 06 3.29e 08/

3.29e 07 Applicator Applying with a Groundboom ( 3) sod farms 3 80 2.00e 06/

2.00e 05 2.00e 06/

2.00e 05 1.73e 06/

1.73e 05 1.41e 06/

1.41e 05 1.14e 06/

1.14e 05 4.94e 07/

4.94e 06 herbaceous ornamentals 3 40 1.00e 06/

1.00e 05 1.00e 06/

1.00e 05 8.67e 07/

8.67e 06 7.06e 07/

7.06e 06 5.71e 07/

5.71e 06 2.47e 07/

2.47e 06 golf courses 4 40 1.34e 06/

1.34e 05 1.34e 06/

1.34e 05 1.16e 06/

1.16e 05 9.42e 07/

9.42e 06 7.61e 07/

7.61e 06 3.29e 07/

3.29e 06 Table 6: Exposure Variables, Cancer for Uses of Oxadiazon Exposure Scenario ( Scenario #) Crop/ Target Appl Rates ( lb ai/ acre) Daily Acres Treated Cancer Base line PPE 1 PPE 2 PPE 3 PPE 4 Eng. Control 26 conifer nurseries, woody ornamentals 4 40 1.34e 06/

1.34e 05 1.34e 06/

1.34e 05 1.16e 06/

1.16e 05 9.42e 07/

9.42e 06 7.61e 07/

7.61e 06 3.29e 07/

3.29e 06 Applying with a Rights of Way Sprayer ( 4) roadsides 4 40 8.07e 05/

8.07e 04 2.60e 05/

2.60e 04 2.00e 05/

2.00e 04 2.40e 05/

2.40e 04 1.80e 05/

1.80e 04 NA Applying Wettable Powders for Handgun Applicators ( ORETF) ( 5) lawns, parks, recreational areas 4 5 See PPE 5.57e 06/

5.57e 05 2.94e 06/

2.94e 05 5.50e 06/

5.50e 05 2.87e 06/

2.87e 05 NA Applying Granular with a Tractor Drawn Spreader ( 6) sod farms 4 80 9.31e 07/

9.31e 06 8.23e 07/

8.23e 05 7.03e 07/

7.03e 06 3.95e 07/

3.95e 06 2.75e 07/

2.75e 06 1.82e 07/

1.82e 06 golf courses 4 40 4.66e 07/

4.66e 06 4.11e 07/

4.11e 06 3.51e 07/

3.51e 06 1.98e 07/

1.98e 06 1.38e 07/

1.38e 06 9.11e 08/

9.11e 07 Mixer/ Loader/ Applicator Backpack Sprayer ( LCO) ( 7) l a w n s , g o l f c o u r s e s ,

ornamentals nurseries 4 5 See PPE 2.13e 05/

2.13e 04 1.45e 05/

1.45e 04 1.93e 05/

1.93e 04 1.25e 05/

1.25e 04 NA Low Pressure Handwand  Wettable Powder Formulations ( LCO) ( 8) lawns, golf courses, nursery stock 4 5 3.10e 04/

3.10e 03 1.56e 04/

1.56e 03 1.38e 04/

1.38e 03 8.30e 05/

8.30e 04 6.50e 05/

6.50e 04 NA High Pressure Handwand  ( Wettable Powder Formulations) ( 9) woody ornamentals, conifer nurseries. 4 5 See PPE 1.88e05/

1.88e 04 1.20e 05/

1.20e 04 1.98e 05/

1.98e 04 1.31e 05/

1.31e 04 NA Lawn Handgun ( Wettable Powder Formulations) ( ORETF) ( 10) ornamentals, lawns, parks rec areas 4 5 1.06e 05/

1.06e 04 1.06e 05/

1.06e 04 8.03e 06/

8.03e 05 6.44e 06/

6.44e 05 3.89e 06/

3.89e 05 NA Granulars with a Push Type Spreader ( ORETF) ( 11) lawns, golf courses, parks,

recreational areas, ornamentals 4 5 2.33e 06/

2.33e 05 1.80e 06/

1.80e 05 No data 1.80e 06/

1.80e 05 No data NA Granulars with a Bellygrinder ( LCO) ( 12) golf courses, parks, rec areas. 4 1 1.61e 05/

1.61e 04 1.50e 05/

1.50e 04 9.60e 06/

9.60e 05 1.42e 05/

1.42e 04 8.77e 06/

8.77e 05 NA Baseline dermal unit exposure scenarios includes long pants, long shirts and no gloves.

PPE 1 cancer risk includes long pants, long shirts, gloves and no respirator.

PPE 2 cancer risk includes long pants, long shirts, double layer, gloves and no respirator.

PPE 3 cancer risk includes long pants, long shirts, gloves and respirator.

PPE 4 cancer risk includes long pants, long shirts, double layer, gloves and respirator.

Engineering Control dermal unit exposure scenarios includes long pants, long shirts, gloves and water soluble packages.

Engineering inhalation unit exposure represents no respirator. 27 Two exposure frequencies were used for cancer, the first represented the maximum number of applications per site per season to represent private use ( 3), and the second frequency applied a factor of ten to the first frequency to represent commercial handlers making multiple applications per site per season ( 30). NA= Not applicable 3.0 POSTAPPLICATION EXPOSURES 3.1 Postapplication Exposure & Assumption HED uses the term " post application" to describe those individuals who can be exposed to pesticides after entering areas previously treated with pesticides and performing certain tasks or activities ( also often referred to as reentry exposure). Most of the oxadiazon used in agriculture is applied either pre plant or when the crops are quite small ( early post emergence). This fact, and the degree of mechanization, minimizes the postapplication contact of workers with oxadiazon. However, The Agency has determined that there are potential postapplication exposures to individuals re entering oxadiazon treated areas for the purpose of:

° Roadsides: mowing ° Bermuda grass rights of way: mowing ° Sod farms: mowing and harvesting ° Golf course turfgrass: mowing 3.1.1 Data Source and Assumptions for Scenario Considered Although two transferable turf residues ( TTR) studies ( MRID# 449955 01and 449955 02) and one Jazzercize study ( MRID# 435178 01) were submitted in support of the reregistration of oxadiazon, only the Jazzercize study found to be acceptable for this assessment. The TTR studies were reviewed and found to have TTR transfer efficiencies of less than1% ( transfer efficiency = % of the application rate). TTR data generated by ORETF members rely on a modified version of the California roller ( ORETF roller) that appears to have a much lower transfer efficiency ( percent of application rate) than the original version. Many TTR data submitted by ORETF members show percent transferabilities of less than 1% of the application rate for sprayable formulations and less than 0.5% of the application rate for granular formulations. ORD has conducted a round robin test of TTR methods that included the ORETF roller ( Fortune 1997). While ORD concluded that the ORETF roller performed the best of all methods, transfer efficiency for three liquid herbicide formulations indicated a transfer efficiency of ~ 0.5%. The ORETF data was not used with the revised Transfer Coefficients referenced in current residential SOP since these revised TCs are based on TTR transfer efficiencies of ~ 1 5% ( transfer efficiency = % of the application rate). Therefore the TTR values from these studies are not included in this assessment. The Jazzercize study ( MRID # 435178 01) was reviewed and found to be acceptable for this assessment.

MRID 435178 01. Evaluation of Turf Re entry Exposure to a Broadcast Application of Ronstar ® 50 WP, L. Rosenheck ( 1995). Pan Agricultural Labs, Inc. Number: 93293 Unpublished study prepared by Rhone Poulenc AG Company. 300 pages. 28 This study on turf transferable residues ( TTR) was submitted by Rhone Poulenc Ag Company, in response to an occupational/ residential exposure Data Call In, and in support of oxadiazon re registration requirements. Ronstar ® 50 WP a wettable powder product containing ~ 50 % oxadiazon, was applied to turf in North Carolina. The study was conducted in order to quantify the dermal exposure associated with re entry onto oxadiazon treated turf. Ronstar ® 50 WP which is labeled for use on dormant, Bermuda grass, St. Augustine grass and Zoisia turf in areas such as fairways, parks, and lawns was used at a maximum label rate of 3 .0 lb ai/ A. Two different exposure scenarios were monitored:

a) Application at the maximum label rate followed by re entry as soon as the turf was dry. b) Application within 30 minuted by sprinkler irrigation of 1/ 10 inch of water with re entry occurring as soon as the turf is dry.

Overall, the study met most criteria of the OPPTS Post application Exposure Monitoring Test Guidelines, 875.2100, Transferable Residue Dissipation: Lawn and Turf.

Most of the field samples returned results that were < LOQ for oxadiazon,. No LOD value was defined in the study, however. The overall mean recovery for field fortification samples of oxadiazon ranged between 64.7 to 99.6%. On Day 0, the highest average turf transferable residues ( TTR) for non irrigated plot was 1.22 µ g per cm 2 and 0.694 µ g per cm 2 on irrigated plot. The TTR values adjusted for an application rate of 4.0 lb ai/ A.

The TTR value from the above study utilized a wettable powder formulation which by far has a higher potential for exposure than the oxadiazon granular formulations. Since 91% of the total use involves granular formulations, using wettable powder TTR values is a conservative approach and can be considered the upper level estimates of exposure.

A linear regression to calculate a dissipation rate ( T ½ ) for oxadiazon TTR from irrigated and non irrigated test sites was performed, using all non zero, uncorrected, averaged data point from DAT 0 through DAT 7. Calculated dissipation half lives for the irrigated plot was 1.7days ( R2= 0.64) and for the non irrigated plot was 1.4 days ( R2= 0.64)

3.1.2 Assumptions Used in Postapplication Exposure Calculations Based on data submitted for reregistration, the most common postapplication exposures will occur for workers on turf. Based on label restrictions and pattern of use, oxadiazon is applied early in the season, either pre plant or before weeds emerge ( pre emergence). Mowing would be a common postapplication activity after either spraying method. Treated turf or grasses will routinely require reentry activities, such as mowing and watering, and eventually harvesting in the case of sod farms.

Because oxadiazon has a low vapor pressure ( 1.0 x 10 6mm Hg) and is only used outdoors, the inhalation component of postapplication exposure is anticipated to be negligible. Therefore, all calculations of postapplication risk estimates have been done for dermal exposure only. Postapplication exposure via the inhalation route is considered to be negligible. 29 Dose ( mg/ kg/ d)

( DFR (

g/ cm 2) x Tc ( cm 2/ hr) x CF 1 mg 1,000

g x Abs x ED ( hrs/ day))

BW MOE

NOAEL ( mg/ kg/ day) Dose ( mg/ kg/ day) 3.1.3 Exposure and Risk Calculations Short and intermediate term daily absorbed doses and MOEs were calculated as follows:

Where: DFR = daily DFR, as calculated above for the assumed average reentry day Tc = transfer coefficient; CF = conversion factor ( i. e., 1 mg/ 1,000

g) Abs = dermal absorption ( 9%) ED = exposure duration; 8 hours worked per day BW = body weight ( 60 kg)

Dermal MOEs were calculated as follows:

Where: NOAEL = 12 mg/ kg/ day for short term and intermediate term Dose = calculated absorbed dermal dose For the purposes of occupational risk assessments, the following residue values were chosen:

° For short term and intermediate term postapplication turf activities, the Residential SOP standard 5% of the amount ai applied is used, along with standard transfer coefficients ( updated 8/ 2000).

3.1.4 Postapplication Exposure Risk Estimates For turf or sod mowing and harvesting, transfer coefficients of 500 and 16,500 cm2/ hr were used, based on the ARTF data ( see HED Exposure SAC Policy guidance 3.1, 8/ 00). As shown in Table C1, short and intermediate  term exposure had an estimated MOEs of 30 1,000. Similarly occupational post application cancer risks were estimated to fall within the acceptable range of 1 x 10 4 to 1 x 10 6. Residential SOP standard value of 5% of application rate used.( see Appendix C, Table C1)

3.2 Non Occupational Postapplication Exposures and Risk Estimates 30 The Agency has determined that there are potential postapplication exposures to residents entering oxadiazon treated lawns, either as a result of commercial or private application.

3.2.1 Postapplication Exposure Scenarios The scenarios likely to result in postapplication exposures are presented below. The duration of postapplication dermal exposure is expected to be either short term or intermediate term, based on oxadiazon turf residue dissipation data. As calculated from the previously discussed Jazzercise study ( MRID # 435178 01), oxadiazon has a half life on turf of up to 1.4 days ( irrigated) and 1.7 days ( non irrigated) after spraying, requiring several days to dissipate to non detectable levels of transferable residues. Because the label prohibits application more than 3 times per year, and even with the slow dissipation rates, it is not expected that individual residential exposure duration would exceed 30 days in duration. Exposure on a residential lawn would diminish continuously with time, while exposure through recreation turf contact would be more like random intermittent events of varying doses, all less than the dose predicted in this assessment. The resulting risk estimates are summarized in Tables C2 ( non cancer) and C3 ( cancer). Residential postapplication exposure assessments assumed residents wear the following attire: short sleeved shirt, short pants, shoes and socks, and no gloves or respirator. As stated in the occupational postapplication risk section of this document, negligible oxadiazon inhalation exposure is anticipated for non handlers, due to low chemical vapor pressure and dilution of vapor outdoors. The scenarios likely to result in postapplication exposures are as follows:

° dermal postapplication risks to adults and toddlers when entering oxadiazon treated turf and lawns;

° oral postapplication risks to toddlers from " hand to mouth" ( i. e., ingestion of grass, soil, granular pellets, or hand to mouth contact) exposure when reentering lawns treated with granular and wettable powder formulations.

Representative turf reentry activities include, but are not limited to:

( 1) Adults involved in a low exposure activity, such as golfing or walking on treated turf. ( 2) Toddlers involved in a low exposure activity, such as walking on treated turf. ( 3) Adults mowing or other moderate contact activity, for 1 2 hours. ( 4) Adults involved in a high exposure activity, such as heavy yard work ( doses similar to occupational scenarios for cutting and harvesting sod). ( 5) Toddlers involved in high exposure activities on turf.

3.2.2 Data Sources for Scenarios Considered A turf re entry exposure study ( Jazzercise study), using a spray application, was described in the Occupational Postapplication exposure section of this document. As the study was found to be acceptable for the risk assessment, the highest mean residues were also used to estimate short term ( DAT 0 1) for irrigated and non irrigated plots. 31 Only limited information was received regarding the size and distribution of granular formulations. This information would help to refine or characterize the estimate of potential risk from episodic incidental ingestion of granules beyond the current screening level. If the particles are very fine, individual grains would be difficult to pick up, or even to see when applied on a lawn. If used according to label directions, it is unlikely that oxadiazon granules would be accessible to a child. However, larger granules or pellets of a few millimeters diameter might be attractive and easily picked up by a toddler.

3.2.3 Assumptions Used in Postapplication Exposure Calculations Dermal Exposure to Golf Course Turfgrass According to a 1992 report from The Center For Golf Course Management, 12.2 percent of the population are golfers ( i. e., 28.5 million people). Golfing is considered a lifetime sport so individuals of all ages, excluding very small children, routinely play. Children who are 12 years of age or older are likely to represent the vast majority of the youth that play golf on any sort of routine basis. However, the popularity of golf as a recreational pastime has increased steadily over the last few years which has resulted in more and more young children ( i. e., less than 12 years old for this discussion) becoming involved in the sport. Risk assessments for these age children are more difficult to complete because of the increased uncertainties associated with any extrapolations using adult dermal exposure data and because of the increased likelihood that other behaviors that might contribute to exposure such as mouthing contaminated hands or golf balls.

Dermal exposures are calculated using the standard transfer coefficient approach that is used for postapplication exposure assessments. ADD( t) ( mg/ kg/ day) = (( TTR( t) (

g/ cm2) x TC ( cm2/ hr) x ET( hr/ day) x ( 1 mg/ 1000

g) )/( BW ( kg))

Where: ADD= average daily dose ( mg/ kg/ day) at time ( t) attributable to golfing on previously treated turf ( mg/ kg/ day); TTR( t)= turf transferable residue at time ( t) (

g/ cm2); TC = transfer coefficient ( cm2/ hour); ET = exposure duration ( hours); and BW = body weight ( kg).

° Duration is 4 hours for a chemical that can be used on all parts of a course ( greens, tees, and fairways). This estimate of the average time it takes to play a round of golf which is based on the report completed by the Center For Golf Course Management [ 1992 Golf Course Operations: Cost of Doing Business/ Profitability. Library of Congress GV975. G56 1992].

° The dose levels calculated for adult golfers can be considered upper level estimates of exposure because of several reasons including the clothing scenario considered ( i. e., shorts and short sleeved shirts are not worn by all golfers), combining average values across several 32 input parameters mathematically results in an upper percentile calculated product.

° Children of various ages down to the very young ( e. g., 4 or 5 years old) are currently playing golf, the agency recognize this but has not yet developed a quantitative approach for calculating their risk, based to analysis of surface area to body weight ratio it appears that the dose for these children may be as much as 1.7 times than for adults.

Dermal Exposure values on each day after application were calculated based on the following equation ( see Residential 2.2 ( 1997): Postapplication dermal potential dose from pesticide residues on turf):

DE( t) ( mg/ day) = ( TTR( t) (

g/ cm2) x TC ( cm2/ hr) x Hr/ Day)/ 1000 (

g/ mg)

Where:

DE = Dermal exposure at time ( t) attributable for activity in a previously treated area ( mg/ day); TTR = Turf Transferable Residue at time ( t) where the longest duration ( t) is dictated by the kinetics observed in the TTR study; TC = Transfer Coefficient; and Hr = Exposure duration in hours.

The activities that were selected as the basis for the risk assessment are represented by the following transfer coefficients ( for short term and intermediate term endpoints):

° Transfer Coefficient = 500 cm2/ hour for adults involved in a low exposure activity on turf such as golfing or light work activities; based on Policy Memo # 003 .1 " Agricultural Transfer Coefficients," Revised  August 7, 2000.. ° Transfer Coefficient = 14,500 cm2/ hour for adults involved in a high exposure activity on turf such as heavy yard work; Based on the revised residential SOP  February 2001 ° Transfer Coefficient = 5200 cm2/ hour for toddler involved in a high exposure activity on turf such as heavy yard work; Based on the revised residential SOP  February 2001 ° Transfer Coefficient = 7,400 cm2/ hour ( non irrigated) for adults involved in a high exposure activity on turf such as heavy yard work; Based on the submitted re entry study ( MRID # 435178 01) ° Transfer Coefficient = 4,300 cm2/ hour ( irrigated) for adults involved in a high exposure activity on turf such as heavy yard work; Based on the submitted re entry study ( MRID # 435178 01) and ° Transfer Coefficient = 2,700 cm2/ hour ( non irrigated) for toddlers involved in a high exposure activity. Based on the submitted re entry study ( MRID # 435178 01) ° Transfer Coefficient = 1,600 cm2/ hour ( irrigated) for toddlers involved in a high exposure activity. Based on the submitted re entry study ( MRID # 435178 01) ° Transfer Coefficient = 16,500 cm2/ hour for sod harvesting ( hand or mechanical); based on Policy Memo # 003 .1 " Agricultural Transfer Coefficients," Revised  August 7, 2000. 33 PDR

( DFR  SA  Freq  Hr  ( 1mg/ 1000

g)) The Agency's Residential SOPs contains guidance for considering children's exposure to treated turf. The dermal calculations, as noted above, were completed based on the guidance provided in the document. All nondietary exposures were also calculated using guidance from this document. Specifically, the kinds of nondietary exposures that were considered in this assessment include the following:

° Dose from hand to mouth activity calculated using Residential SOP 2.3.2: Postapplication potential dose among toddlers from incidental nondietary ingestion of pesticide residues on residential lawns from hand to mouth transfer. ° Dose from mouthing treated turf calculated using Residential SOP 2.3.3: Postapplication potential dose among toddlers from the ingestion of pesticide treated turfgrass; and ° Dose from incidental ingestion of soil calculated using Residential SOP 2.3.4: Postapplication potential dose among toddlers from the ingestion of soil in pesticide treated areas.

Although incidental exposures incurred by hand to mouth exposure are included as part of the nondietary risk assessment, these type of exposures are considered episodic in nature. The hand licking, mouthing of turf, and eating of soil are considered more likely to co occur, with the hand licking constituting the largest incidental oral exposure component.

The following demonstrates the method used to calculate exposures that are attributable to a child touching treated turf and then putting their hands in their mouth ( SOP 2.3.2):

where: PDR = potential dose rate ( mg/ day) DFR( t)= Dislodgeable Residue ( 5%) on day of treatment (

g/ cm2); SA = surface area of two fingers ( cm2); Freq = frequency of hand to mouth events ( events/ hour); and Hr = exposure duration ( hours).

As indicated above, the dislodgeable foliar residue represents the amount of pesticide that can be removed from turf by the ( potentially wet) hands of a child, while the turf transferable residue represents the amount of chemical on the surfaces of treated leaves that can rub off on dry skin or clothing. These observations are based on empirical data, and therefore the Residential SOP standard 5% of the amount ai applied is used, rather than the data from the TTR study. The surface area for 1 3 fingers used ( 20 cm2) is the median surface area for a toddler ( age 3 years) as updated by the SAP in 12/ 99. The frequency of hand to mouth events is 20 events per hour as updated in 12/ 99. The 2 hour duration value is a recommended value from the U. S. EPA Exposure Factors Handbook. This model for hand to mouth dose is based on the premise that a child puts 2 3 fingers in their mouths, 50% of the residues on the hands are transferred from the hands to the mouth, and that all of the dislodgeable residues available on the treated turf transfer to the child's 34 PDR

( DFR  IgR  ( 1mg/ 1000

g)) hand each time they exhibit this behavior.

The following illustrates the approach used to calculate exposures that are attributable to a child mouthing treated turf ( SOP 2.3.3):

where: PDR = potential dose rate ( mg/ day); DFR( t)= Dislodgeable Foliar Residue ( DFR) at time ( t) where the longest duration ( t) is dictated by the kinetics observed in the TTR study (

g/ cm2); and IgR= ingestion rate for mouthing of grass per day ( cm2/ day).

The ingestion rate used ( 25 cm2/ day) assumes that a child will grab a handful of turf, mouth it and remove all oxadiazon residues, and then remove it from their mouth as described in the Residential SOPs. The standard time period is 2 hours, as explained above. The surface area of ( 25 cm2/ day) is thought to approximate a handful of turf that is mouthed. The maximum average TTR values were used for this scenario.

Incidental Soil Ingestion:

PDR = ( SR t * IgR * CF1)

where: PDR = potential dose rate ( mg/ day) SR t = soil residue on day " t" (

g/ g), assuming average day of reentry " t" is day 0 IgR = ingestion rate of soil ( mg/ day), assumed to be 100 mg/ day CF1 = weight unit conversion factor to convert the

g of residues on the soil to grams to provide units of mg/ day ( 1E 6 g/

g) and SR t = AR * F * ( 1 D) t * CF2 * CF3 * CF4 where:

AR = application rate ( lb ai/ acre) F = fraction of ai available in uppermost cm of soil ( fraction/ cm), assumed to be 100 percent based on soil incorporation into top 1 cm of soil after application D = fraction of residue that dissipates daily ( unitless) t = postapplication day on which exposure is being assessed CF2 = weight unit conversion factor to convert the lbs ai in the application rate to

g for the soil residue value ( 4.54 x 108

g/ lb) CF3 = area unit conversion factor to convert the surface area units ( ft2) in the application rate to cm2 for the SR value ( 2.47 x 10 8 acre/ cm2 if the application rate is per acre) 35 CF4 = volume to weight unit conversion factor to convert the volume units ( cm3) to weight units for the SR value ( 0.67 cm3/ g soil) t = postapplication day on which exposure is being assessed, assumed to be day zero The following specific assumptions and factors were used in order to complete this exposure assessment:

These assessments were based on the guidance provided in the Residential SOPs. Several of the assumptions and factors used in the exposure assessment are described in that document.

The TTR values are assumed to be 5 percent of the application rate at day 0 for turfgrass application ( the 5 percent rate for turfgrass is the high end of the values observed in Hurto and Prinster, 1993, Goh et al., 1986, and Cowell et al., 1993,

Calculations are completed at the maximum application rates recommended by the available oxadiazon labels to bracket risk levels associated with the various use patterns and activity scenarios.

Due to a lack of scenario specific exposure data, HED has calculated exposure values for adults using surrogate dermal transfer coefficients that represent activities such as mowing, golfing, and yard work. Most of the transfer coefficients used are based on data submitted by the ARTF and ORETF and are reflected in the revised HED exposure guidance Policy 3.1 ( 8/ 2000).

° For the short and intermediate term risk assessment, the equations and assumptions used for each of the scenarios were taken from the Residential SOPs guidance document.

° Adults were assumed to weigh 60 kg for the short and intermediate term postapplication dermal dose estimate. Toddlers ( 3 years old) were assumed to weigh 15 kg.

° Postapplication exposure is generally assessed on the same day the pesticide is applied because it is assumed that the resident could be exposed to turf immediately after application.

° A dermal absorption factor of 9 % was used in the calculation of short and intermediate term postapplication dermal dose. MOEs were calculated using the same formula ( NOAEL divided by absorbed dermal dose) described in the residential handler portion of this chapter, and are considered to be below the level of concern when results are greater than 100.

3.2.4 Postapplication Exposure Risk Estimates 36 Using the revised residential SOP postapplication short and intermediate term dermal risk estimates for occupational workers are between 30 and 1,000. The cancer risk for all occupational handlers is between 9.92 x 10 5 to 3.01 x 10 6.

Dermal postapplication exposure estimates were conducted using the highest mean postapplication residue from the Jazzercise study( wettable powder formulations). The dermal transfer coefficients from the Jazzercize study and the revised residential SOPs were used. Using the Jazzercize wettable powder application study residue data and revised residential SOPs , all of the scenario had short term and intermediate term dermal MOEs greater than 100 on the application day ( i. e., day 0). The cancer risks for all residential dermal postapplication is between 6.22x 10 6 to 7.51 x 10 7 .

The Residential SOPs and submitted Jazzercize study data were used to estimate incidental oral exposure for toddlers on treated turf. The short term MOE was100 for the toddler hand tomouth using residential SOPs and between 90 to 240 for the submitted Jazzercize study, however since wettable powder formulation has a higher exposure than granular formulation, therefore the MOE, s can be considered upper level estimates of exposure. The intermediate term MOE was not calculated since exposure by this route for weeks to months is considered less likely to occur than short term exposure. Incidental turfgrass mouthing and soil ingestion had MOEs greater than 100 for short term exposures ( see Appendix C Table C4).

Under the Worker Protection Standard ( WPS), interim restricted entry intervals ( REI) for all uses within the scope of the WPS are based on the acute toxicity of the active ingredient. The toxicity categories of the active ingredient for acute dermal toxicity, eye irritation potential, and skin irritation potential are used to determine the interim WPS REI. If one or more of the three acute toxicity effects are in toxicity category I, the interim WPS REI is established at 48 hours. If none of the acute toxicity effects are in category I, but one or more of the three is classified as category II, the interim WPS REI is established at 24 hours. If none of the three acute toxicity effects are in category I or II, the interim WPS REI is established at 12 hours.( all of the three oxadiazon acute toxicity effects are in category III) 3.2.5 Data Gaps and Uncertainties The following data gap or uncertainties were associated with this assessment:

° Granular ingestion is considered episodic, rather than continuous, in nature. 37 APPENDIX A SHORT TERM AND INTERMEDIATE TERM HANDLER EXPOSURE RISK TABLES A1 THROUGH A4 38 Table A1: Occupational Handler Short term and Intermediate term Risk from Oxadiazon at Baseline Exposure Scenario ( Scenario #) Crop type Baseline Dermal Baseline Inhalation Total MOEg Unit Exposure ( mg/ lb ai) a Daily Dose ( mg/ kg/ day) b Dermal MOEc Unit Exposure ( ug/ lb ai) d Daily Dose ( mg/ kg/ day) e Inhalation MOEf Mixer/ Loader Exposure Mixing/ Loading Wettable Powders for Chemigation Application ( 1a) sod farms 3.7 5.8 2.0 43 0.75 16 2 Mixing/ Loading Wettable Powders for Groundboom Application ( 1b) conifer nurseries, woody ornamentals 0.89 14 0.11 100 12 herbaceous ornamentals 0.67 18 0.086 140 16 sod farms 1.3 9 0.17 70 8 golf courses 0.89 14 0.11 100 12 Mixing/ Loading Wettable Powders for Rights of Way Sprayer ( 1c) roadside turf, ornamentals 0.89 14 0.11 100 12 Loading Granular formulations ( 2) sod farms, conifers forest 0.0084 0.004 3000 1.7 0.0091 1300 920 golf course turf, parks, recreational areas 0.002 6000 0.0045 2600 1800 woody ornamentals 0.002 6000 0.0045 2600 1800 Applicator Applying with a Groundboom ( 3) sod farms 0.014 0.005 2400 0.74 0.003 4100 1500 herbaceous ornamentals 0.0025 4800 0.0015 8100 3000 golf courses 0.0034 3600 0.002 6100 2300 conifer nurseries, woody ornamentals 0.0034 3600 0.002 6100 2300 Applying with a Rights of Way Sprayer ( 4) roadsides 1.3 0.31 38 3.9 0.01 1200 37 Applying Wettable Powders for Handgun Applicators ( ORETF) ( 5) lawns, parks, recreational areas See PPE See PPE See PPE 1 0 36000 See PPE Applying Granular with a Tractor Drawn Spreader ( 6) sod farms 0.0099 0.0048 2500 1.2 0.0064 1900 1100 golf courses 0.0099 0.0024 5100 1.2 0.0032 3800 2200 Table A1: Occupational Handler Short term and Intermediate term Risk from Oxadiazon at Baseline Exposure Scenario ( Scenario #) Crop type Baseline Dermal Baseline Inhalation Total MOEg Unit Exposure ( mg/ lb ai) a Daily Dose ( mg/ kg/ day) b Dermal MOEc Unit Exposure ( ug/ lb ai) d Daily Dose ( mg/ kg/ day) e Inhalation MOEf 39 Mixer/ Loader/ Applicator Backpack Sprayer ( LCO) ( 7) lawns, golf courses, ornamentals nurseries See PPE See PPE See PPE 30 0.01 1200 See PPE Low Pressure Handwand  Wettable Powder Formulations ( LCO) ( 8) lawns, golf courses, nursery stock 29 0.87 14 1100 0.37 33 10 High Pressure Handwand  ( Wettable Powder Formulations) ( 9) woody ornamentals, conifer nurseries. See PPE See PPE See PPE 120 0.04000 300 See PPE Lawn Handgun ( Wettable Powder Formulations)

( ORETF) ( 10) ornamentals, lawns, parks rec areas 0.99 0.022 560 62 0.021 580 280 Granulars with a Push Type Spreader ( ORETF) ( 11) l awn s , g o l f c o u r s e s , p a r k s ,

recreational areas, ornamentals 0.35 0.011 1100 0.0075 2.50e 06 4800000 1100 Granulars with a Bellygrinder ( LCO) ( 12) golf courses, parks, rec areas. 10 0.06 200 62 0.0041 2900 190 a Baseline dermal unit exposure scenarios includes long pants, long shirts and no gloves.

b Daily Dermal Dose ( mg/ kg/ day) = Daily Dermal Exposure ( mg/ day)/ Body weight ( 60 kg)* Dermal Absorption Factor ( 9%) .

c Short term or Intermediate term Dermal MOE = NOAEL ( 12 mg/ kg/ day)/ Daily Dermal Dose ( mg/ kg/ day).

d Baseline inhalation unit exposure represents no respirator e Daily Inhalation Dose ( mg/ kg/ day) = Daily Inhalation Exposure ( mg/ day)/ Body weight ( 60 kg).

f Short term or Intermediate term Inhalation MOE = NOAEL ( 12 mg/ kg/ day)/ Daily Inhalation Dose ( mg/ kg/ day).

g Total Dermal MOE = 1/ (( 1/ Dermal MOE) + ( 1/ Inhalation MOE)). 40 Table A2: Occupational Handler Short term and Intermediate term Risk from Oxadiazon at PPE Exposure Scenario ( Scenario #) Crop type PPE Dermal PPE Inhalation Total MOEg Unit Exposure ( mg/ lb ai) a Daily Dose ( mg/ kg/ day) b Dermal MOEc Unit Exposure ( ug/ lb ai) d Daily Dose ( mg/ kg/ day) e Inhalation MOEf Mixer/ Loader Exposure Mixing/ Loading Wettable Powders for Chemigation Application ( 1a) sod farms 0.13 ( gl, dl) 0.2 59 8.6 dust/

mist respirator 0.15 80 35 Mixing/ Loading Wettable Powders for Groundboom Application ( 1b) conifer nurseries, woody ornamentals 0.031 380 0.023 520 220 herbaceous ornamentals 0.023 510 0.017 700 300 sod farms 0.047 260 0.034 350 150 golf courses 0.031 380 0.023 520 220 Mixing/ Loading Wettable Powders for Rights of Way Sprayer ( 1c) roadside turf, ornamentals 0.031 380 0.023 520 220 Loading Granular formulations ( 2) sod farms, conifers forest NA NA NA NA NA NA NA golf course turf, parks, recreational areas NA NA NA NA NA woody ornamentals NA NA NA NA NA Applicator Applying with a Groundboom ( 3) sod farms NA NA NA NA NA NA herbaceous ornamentals NA NA NA NA NA golf courses NA NA NA NA NA conifer nurseries, woody ornamentals NA NA NA NA NA Applying with a Rights of Way Sprayer ( 4) roadsides 0.39 ( gl) 0.094 130 3.9 ( no resp) 0.01 1200 120 Applying Wettable Powders for Handgun Applicators ( ORETF) ( 5) lawns, parks, recreational areas 0.73 ( gl) 0.022 550 1.0 ( no resp) 0.00030 36000 540 Applying Granular with a Tractor Drawn Spreader ( 6) sod farms NA NA NA NA NA NA NA golf courses NA NA NA NA NA NA NA Table A2: Occupational Handler Short term and Intermediate term Risk from Oxadiazon at PPE Exposure Scenario ( Scenario #) Crop type PPE Dermal PPE Inhalation Total MOEg Unit Exposure ( mg/ lb ai) a Daily Dose ( mg/ kg/ day) b Dermal MOEc Unit Exposure ( ug/ lb ai) d Daily Dose ( mg/ kg/ day) e Inhalation MOEf 41 Mixer/ Loader/ Applicator Backpack Sprayer ( LCO) ( 7) lawns, golf courses, ornamentals nurseries 2.5 ( gl) 0.075 160 30 ( no resp) 0.01 1200 140 Low Pressure Handwand  Wettable Powder Formulations ( LCO) ( 8) lawns, golf courses, nursery stock 6.2 ( gl dl) 0.19 65 220 dust/

mist resp 0.073 160 46 High Pressure Handwand  ( Wettable Powder Formulations) ( 9) woody ornamentals, conifer nurseries. 2.5 ( gl) 0.075 160 120 ( no resp) 0.040 300 100 Lawn Handgun ( Wettable Powder Formulations)

( ORETF) ( 10) ornamentals, lawns, parks rec areas NA NA NA NA NA NA NA Granulars with a Push Type Spreader ( ORETF)

( 11) lawns, golf courses, parks, recreational areas,

ornamentals NA NA NA NA NA NA NA Granulars with a Bellygrinder ( LCO) ( 12) golf courses, parks, rec areas. NA NA NA NA NA NA NA a PPE dermal unit exposure includes long pants, long shirts and gloves for scenarios 5, 7, and 9. PPE dermal unit exposure includes long pants, long shirts gloves and double layer ( 50%

protection) for scenarios 1a, 1b, 1c, and 8.

b Daily Dermal Dose ( mg/ kg/ day) = Daily Dermal Exposure ( mg/ day)/ Body weight ( 60 kg)* Dermal Absorption Factor ( 9%) .

c Short term or Intermediate term Dermal MOE = NOAEL ( 12 mg/ kg/ day)/ Daily Dermal Dose ( mg/ kg/ day).

d PPE inhalation unit exposure represents dust/ mist respirator for scenarios 1a, 1b, 1c, and 8.

e Daily Inhalation Dose ( mg/ kg/ day) = Daily Inhalation Exposure ( mg/ day)/ Body weight ( 60 kg).

f Short term or Intermediate term Inhalation MOE = NOAEL ( 12 mg/ kg/ day)/ Daily Inhalation Dose ( mg/ kg/ day).

g Total Dermal MOE = 1/ (( 1/ Dermal MOE) + ( 1/ Inhalation MOE)).

NA= Not applicable 42 Table A3: Occupational Handler Short term and Intermediate term Risk from Oxadiazon at Engineering Control Exposure Scenario ( Scenario #) Crop type PPE Dermal PPE Inhalation Total MOEg Unit Exposure ( mg/ lb ai) a Daily Dose ( mg/ kg/ day) b Dermal MOEc Unit Exposure ( ug/ lb ai) d Daily Dose ( mg/ kg/ day) e Inhalation MOEf Mixer/ Loader Mixing/ Loading Wettable Powders for Chemigation Application ( 1a) sod farms 0.0098 ( water soluble Packages) 0.015 780 0.24 0.00420 2900 610 Mixing/ Loading Wettable Powders for Groundboom Application ( 1b) conifer nurseries, woody ornamentals NA NA NA NA NA herbaceous ornamentals NA NA NA NA NA sod farms NA NA NA NA NA golf courses NA NA NA NA NA Mixing/ Loading Wettable Powders for Rights of Way Sprayer ( 1c) roadside turf, ornamentals NA NA NA NA NA Loading Granular formulations ( 2) sod farms, conifers forest NA NA NA NA NA NA NA golf course turf, parks, recreational areas NA NA NA NA NA woody ornamentals NA NA NA NA NA Applicator Applying with a Groundboom ( 3) sod farms NA NA NA NA NA NA herbaceous ornamentals NA NA NA NA NA golf courses NA NA NA NA NA conifer nurseries, woody ornamentals NA NA NA NA NA Applying with a Rights of Way Sprayer ( 4) roadsides NA NA NA NA NA NA NA Applying Wettable Powders for Handgun Applicators ( ORETF)

( 5) lawns, parks, recreational areas NA NA NA NA NA NA NA Applying Granular with a Tractor Drawn Spreader ( 6) sod farms NA NA NA NA NA NA NA Table A3: Occupational Handler Short term and Intermediate term Risk from Oxadiazon at Engineering Control Exposure Scenario ( Scenario #) Crop type PPE Dermal PPE Inhalation Total MOEg Unit Exposure ( mg/ lb ai) a Daily Dose ( mg/ kg/ day) b Dermal MOEc Unit Exposure ( ug/ lb ai) d Daily Dose ( mg/ kg/ day) e Inhalation MOEf 43 golf courses NA NA NA NA NA NA NA Mixer/ Loader/ Applicator Backpack Sprayer ( LCO) ( 7) lawns, golf courses, ornamentals nurseries NA NA NA NA NA NA NA Low Pressure Handwand  Wettable Powder Formulations ( LCO)

( 8) lawns, golf courses, nursery stock NF NF NF NF NF NF NF High Pressure Handwand  ( Wettable Powder Formulations) ( 9) woody ornamentals, conifer nurseries. NA NA NA NA NA NA NA Lawn Handgun ( Wettable Powder Formulations) ( ORETF) ( 10) ornamentals, lawns, parks rec areas NA NA NA NA NA NA NA Granulars with a Push Type Spreader ( ORETF) ( 11) l awns, gol f c o u r s e s , p a rk s,

recreational areas, ornamentals NA NA NA NA NA NA NA Granulars with a Bellygrinder ( LCO) ( 12) golf courses, parks, rec areas. NA NA NA NA NA NA NA a Engineering Control dermal unit exposure scenarios includes long pants, long shirts, gloves and water soluble packages for scenario 1a.

b Daily Dermal Dose ( mg/ kg/ day) = Daily Dermal Exposure ( mg/ day)/ Body weight ( 60 kg)* Dermal Absorption Factor ( 9%) .

c Short term or Intermediate term Dermal MOE = NOAEL ( 12 mg/ kg/ day)/ Daily Dermal Dose ( mg/ kg/ day).

d inhalation unit exposure represents no respirator e Daily Inhalation Dose ( mg/ kg/ day) = Daily Inhalation Exposure ( mg/ day)/ Body weight ( 60 kg).

f Short term or Intermediate term Inhalation MOE = NOAEL ( 12 mg/ kg/ day)/ Daily Inhalation Dose ( mg/ kg/ day).

g Total Dermal MOE = 1/ (( 1/ Dermal MOE) + ( 1/ Inhalation MOE)).

NA = Not applicable NF = Not feasible 44 Table A4 : Exposure Scenario Descriptions for the Use of Oxadiazon Exposure Scenario # Data Source Standard Assumptionsa ( 8 hr work day) Commentsb Mixer/ Loader Descriptors Mixing/ Loading Wettable Powder Formulations ( 1a/ 1b/ 1c) PHED V1.1 350 acres for chemigation,

80 acres for groundboom in sod farms, 40 acres for groundboom on golf course turf, 5 acres/ day for the turf loading scenarios Baseline: Hands, dermal and inhalation = ABC grades. Hands = 7 replicates, dermal = 22 45 replicates and inhalation = 44 replicates. Low confidence in dermal, hands data due to the low number of hand replicates. Medium confidence in inhalation data.

PPE: Gloved data for hands = ABC grades. Hands = 24 replicates. Medium confidence in hands data.

Dermal values calculated by applying a 50% protection factor to baseline values to account for an additional layer of clothing. A 5 fold PF ( e. g. 80% PF was applied to the baseline inhalation data).

Engineering Controls: Water soluble bags. Dermal = AB grades. Hands and inhalation = All grade.

Inhalation = 15 replicates, dermal = 6 15 replicates and hands = 5 replicates. Low confidence in the dermal, hands and inhalation data.

Loading Granular Formulations ( 2) PHED V1.1 80 acres for tractor drawn spreaders for most crops; 40 acres for golf course turf Baseline: Low confidence in dermal and hand data ( due to low hand replicates). High confidence in inhalation data. No protection factors were needed to define the unit exposure values.

Applicator Descriptors Groundboom Application ( 3) PHED V1.1 80 acres for tractor drawn spreaders for sod farms; 40 acres for golf course turf Baseline: Dermal ( 23 to 42 replicates); hand ( 29 replicates); and inhalation ( 22 replicates) exposure values are based on AB grade data. High confidence in the unit exposure values. No protection factors were required to define the unit exposure value.

Applying Liquids with Rights of

Way Sprayer ( 4) PHED V1.1 40 acres Baseline: Dermal ( 4 to 20 replicates) exposure value is based on ABC grade data. Hand ( 16 replicates)

exposure value based on AB grade data and inhalation ( 16 replicates) exposure value is based on A grade data. Low confidence in the dermal unit exposure value and high confidence in the inhalation data. No protection factors were needed to define the unit exposure value.

PPE: The same dermal and inhalation data are used as for the baseline coupled, if needed, with a 50%

protection factor to account for an additional layer of clothing and an 80% protection factor to account for the use of a dust/ mist respirator. Gloved hand ( 4 replicates) exposure value is based on AB grade data. Low confidence in the dermal/ hand unit exposure value.

Engineering Controls: Not available for this scenario.

Applying Liquids with a Handgun ( 5) ( ORTEF) ORTEF 5 acres Baseline: Inhalation ( 90 replicates) exposure value is based on B grade data.

PPE: Hand ( 90 replicates) and dermal ( 90 replicates) exposure values are based on B grade data.

Engineering Controls: Not available for this scenario Applying Granulars with a Tractor Drawn Spreader ( 6) PHED V1.1 40 acres for golf course turf Baseline: Low confidence in hand, dermal, and inhalation data. No protection factors were required to define the unit exposure values.

Mixer/ Loader/ Applicator Descriptors Table A4 : Exposure Scenario Descriptions for the Use of Oxadiazon Exposure Scenario # Data Source Standard Assumptionsa ( 8 hr work day) Commentsb 45 Mixing/ Loading/ Applying with a Backpack Sprayer ( 7) PHED V1.1 5 acres for occupational uses Baseline: Only low confidence inhalation data available ( no non gloved hand monitoring data are available, therefore the assessment was not completed).

PPE: Low confidence single layer clothing dermal monitoring data available, coupled with a 50%

protection factor to account for an additional layer of clothing. Inhalation data coupled with a 90%

protection factor to account for the use of a respirator. Hand exposure data with gloves were monitored ( considered low confidence).

Engineering Controls: Not feasible Mixing/ Loading/ Applying Liquids with a Low Pressure Handwand ( 8) PHED V1.1 5 acres for occupational uses Baseline: Dermal and inhalation data = ABC grades, and hands data = All grade. Dermal = 9 80 replicates; hands = 70 replicates; and inhalation = 80 replicates. Low confidence in hands, dermal data.

Medium confidence in inhalation data.

PPE and Engineering Controls: Not required for assessment.

Mixing/ Loading/ Applying with a High Pressure Handwand ( 9) PHED V1.1 5 acres Baseline: Only low confidence inhalation data available ( no non gloved hand monitoring data are available, therefore the assessment was not completed).

PPE: Low confidence single layer clothing dermal monitoring data available, coupled with a 50%

protection factor to account for an additional layer of clothing. Inhalation data coupled with a 90%

protection factor to account for the use of a respirator. Hand exposure data with gloves were monitored ( considered low confidence).

Engineering Controls: Not feasible Mixing/ Loading/ Applying with a Handgun ( turf grass application)

( 10) ORTEF 5 acres for occupational uses. Data for open mixing of liquids and handgun turfgrass application were combined to generate mixer/ loader/ applicator value as this is the most likely exposure scenario.

Baseline for application: Low confidence in hand, dermal, and inhalation data. Baseline dataset was based on the use of chemical resistant gloves. Therefore, a reverse 80% PF was used on the gloved hand data to assess baseline exposure for individuals wearing no gloves ( i. e., it is a typical use scenario demanding a baseline assessment and the exposures are generally lower compared with other handheld methods).

PPE for applicator: As appropriate, the same dermal, hand, and inhalation data are used as for the baseline coupled with a 50% protection factor to account for an additional layer of clothing and a 80%

protection factor to account for the use of a respirator. Hand exposure data with gloves were monitored ( considered low confidence).

Engineering Controls: Not feasible.

Mixing/ Loading/ Applying with a Push Type Granular Spreader ( 11) ORTEF 5 acres for occupational uses. Baseline: Low confidence in the dermal and hand data. High confidence in the inhalation data. No protection factors were required to define the unit exposure values ( a 50 percent protection factor was used to back calculate the homeowner exposure scenario).

Mixing/ Loading/ Applying with a Bellygrinder ( 12) PHED V1.1 5 acres for occupational uses. Baseline: Medium confidence in hand and dermal data. High confidence in inhalation data. No protection factors were required to define the unit exposure values ( also applies to homeowner scenarios).

a All Standard Assumptions are based on a typical work day ( the components that involve pesticide use) as estimated by HED.

b All handler exposure assessments in this document are based on the " Best Available" data as defined by the PHED SOP for meeting Subdivision U Guidelines ( i. e., completing exposure assessments). Best available grades are assigned to data as follows: matrices with A and B grade data ( i. e., Acceptable Grade Data) and a minimum of 15 replicates; if not available, then grades 46 A, B and C data and a minimum of 15 replicates; if not available, then all data regardless of the quality ( i. e., All Grade Data) and number of replicates. Generic data confidence categories are assigned as follows:

High = grades A and B and 15 or more replicates per body part Medium = grades A, B, and C and 15 or more replicates per body part Low = grades A, B, C, D and E or any combination of grades with less than 15 replicates.

Protection factors applied to exposure data for the use of respiratory protection, protection afforded with the use of an additional layer of clothing, and protection from the use of chemical resistant gloves are as follows: 90 % ( respirator); 50 % ( layer of clothing); and 90% ( gloves). 47 APPENDIX B OCCUPATIONAL HANDLER CANCER ( Q*) RISKS TABLES B1  B4 48 Table B1: Occupational Handler, Cancer ( Q*) Risk from Oxadiazon at baseline Exposure Scenario # Crop Type Total Baseline Daily Dose ( mg/ kg/ day) a Baseline Daily LADDb 3/ 30 days Baseline Riskc Mixer/ Loader Exposure Mixing/ Loading Wettable Powders for Chemigation Application ( 1a) sod farms 5.600 2.30e 02/ 2.30e 01 1.65e 03/ 1.65 02 Mixing/ Loading Wettable Powders for Groundboom Application ( 1b) conifer nurseries, woody ornamentals 0.860 3.50e 03/ 3.5e 02 2.51e 04/ 2.51e 03 herbaceous ornamentals 0.640 2.60e 03/ 2.60e 02 1.88e 04/ 1.88e 03 sod farms 1.300 5.30e 03/ 5.30e 02 3.77e 04/ 3.77e 03 golf courses 0.860 3.50e 03/ 3.50e 02 2.51e 04/ 2.51e 03 Mixing/ Loading Wettable Powders for Rights of Way Sprayer ( 1c) roadside turf, ornamentals 0.860 3.50e 03/ 3.50e 02 3.14e 05/ 3.14e 04 Loading Granular formulations ( 2) sod farms, conifers forest 0.011 4.60e 04/ 4.60e 03 3.28e 06/ 3.28e 05 golf course turf, parks, recreational areas 0.0056 2.30e 05/ 2.30e 04 1.64e 06/ 1.64e 05 woody ornamentals 0.0056 2.30e 05/ 2.30e 04 1.64e 06/ 1.64e 05 Applicator Applying with a Groundboom ( 3) sod farms 0.007 2.80e 05/ 2.80e 04 2.00e 06/ 2.00e 05 herbaceous ornamentals 0.003 1.40e 05/ 1.40e 04 1.00e 06/ 1.00e 05 golf courses 0.005 1.90e 05/ 1.90e 04 1.34e 06/ 1.34e 05 conifer nurseries, woody ornamentals 0.005 1.90e 05/ 1.90e 04 1.34e 06/ 1.34e 05 Applying with a Rights of Way Sprayer ( 4) roadsides 0.280 1.10e 03/ 1.10e 02 8.07e 05/ 8.07e 04 Applying Wettable Powders for Handgun Applicators ( ORETF) ( 5) lawns, parks, recreational areas See PPE See PPE See PPE/

Applying Granular with a Tractor Drawn Spreader ( 6) sod farms 0.010 1.30e 05/ 1.30e 04 9.31e 07/ 9.31e 06 golf courses 0.005 6.50e 06/ 6.50e 05 4.66e 07/ 4.66e 06 Mixer/ Loader/ Applicator Backpack Sprayer ( LCO) ( 7) lawns, golf courses, ornamentals nurseries See PPE See PPE See PPE Low Pressure Handwand  Wettable Powder Formulations ( LCO) ( 8) lawns, golf courses, nursery stock 1.060 4.40e 03/ 4.40e 02 3.10e 04/ 3.10e 03 Table B1: Occupational Handler, Cancer ( Q*) Risk from Oxadiazon at baseline Exposure Scenario # Crop Type Total Baseline Daily Dose ( mg/ kg/ day) a Baseline Daily LADDb 3/ 30 days Baseline Riskc 49 High Pressure Handwand  ( Wettable Powder Formulations) ( 9) woody ornamentals, conifer nurseries. See PPE See PPE See PPE Lawn Handgun ( Wettable Powder Formulations) ( ORETF) ( 10) ornamentals, lawns, parks rec areas 0.036 1.50e 04/ 1.50e 03 1.06e 05/ 1.06e 04 Granulars with a Push Type Spreader ( ORETF) ( 11) lawns, golf courses, parks, recreational areas,

ornamentals 0.008 3.30e 05/ 3.30e 04 2.33e 06/ 2.33e 05 Granulars with a Bellygrinder ( LCO) ( 12) golf courses, parks, rec areas. 0.055 2.30e 04/ 2.30e 03 1.61e 05/ 1.61e 04 a Baseline Total Daily Dose = [ Baseline Daily Dermal Exposure ( mg/ day) * Dermal absorption factor ( 9%) + Baseline Daily Inhalation Exposure ( mg/ day)]/ Body Weight ( 70 kg).

b Baseline LADD ( mg/ kg/ day) = Baseline Total Daily Dose ( mg/ kg/ day) * ( Number of days exposed per year) / 365 days per year) * 35 years worked/ 70 year lifetime.

c Baseline Total Cancer Risk = Baseline LADD ( mg/ kg/ day) * ( Q 1*), where Q 1* = 7.11e 2 ( mg/ kg/ day) 1.

Baseline cancer risk includes long pants, long shirts no gloves and no respirator.

Two exposure frequencies were used for cancer, the first represented the maximum number of applications per site per season to represent private use ( 3), and the second frequency applied a factor of ten to the first frequency to represent commercial handlers making multiple applications per site per season ( 30). 50 Table B2: Occupational Handler, Cancer ( Q*) Risk from Oxadiazon at PPE Exposure Scenario # Crop Type Total PPE 1 Daily Dose ( mg/ kg/ day) a PPE 1 LADDb 3/ 30 days PPE 1 Riskc Total PPE 2 Daily Dose ( mg/ kg/ day) a PPE 2 LADDb 3/ 30 days PPE2 Riskc Mixer/ Loader Exposure Mixing/ Loading Wettable Powders for Chemigation Application ( 1a) sod farms 0.870 3.58e 03/

3.58e 02 2.56e 04/

2.56e 03 0.82 3.37e 01/

3.37e 02 2.40e 04/

2.40e 03 Mixing/ Loading Wettable Powders for Groundboom Application ( 1b) conifer nurseries, woody ornamentals 0.130 5.48e 04/

5.48e 03 3.89e 05/

3.89e 04 0.130 5.14e 4/

5.14e 03 3.65e 05/

3.65e 04 herbaceous ornamentals 0.100 4.11e 04/

4.11e 03 2.92e 05/

2.92e 04 0.094 3.85e 04/

3.85e 03 2.74e 05/

2.74e 04 sod farms 0.200 8.22e 04/

8.22e 03 5.84e 05/

5.84e 04 0.190 7.71e 04/

7.71e 03 5.48e 05/

5.48e 04 golf courses 0.130 5.48e 04/

5.48e 03 3.89e 05/

3.89e 04 0.130 5.14e 04/

5.14e 04 3.65e 05/

3.65e 04 Mixing/ Loading Wettable Powders for Rights of Way Sprayer ( 1c) roadside turf, ornamentals 0.130 5.48e 04/

5.48e 03 3.89e 05/

3.89e 04 0.016 5.14e 04/

5.14e 03 4.57e 06/

4.57e 04 Loading Granular formulations ( 2) sod farms, conifers forest 0.011 4.36e 05/

4.36e 04 3.10e 06/

3.10e 05 0.009 3.77e 05/

3.77e 04 2.68e 06/

2.68e 05 golf course turf, parks, recreational areas 0.005 2.18e 05/

2.18e 04 1.55e 06/

1.55e 05 0.0046 1.88e 05/

1.88e 04 1.34e 06/

1.34e 05 woody ornamentals 0.005 2.18e 05/

2.18e 04 1.55e 06/

1.55e 05 0.0046 1.88e 05/

1.88e 04 1.34e 06/

1.34e 05 Applicator Applying with a Groundboom ( 3) sod farms 0.007 2.82e 05/

2.82e 04 2.00E 06/

2.00e 05 0.0059 2.44e 05/

2.44e 04 1.73e 06/

1.73e 05 herbaceous ornamentals 0.003 1.41e 05/

1.41e 04 1.00e 06/

1.00e 05 0.003 1.22e 05/

1.22e 04 8.67e 07/

8.67e 06 golf courses 0.005 1.88e 05/

1.88e 04 1.34e 06/

1.34e 05 0.004 1.63e 05/

1.63e 04 1.16e 06/

1.16e 05 conifer nurseries, woody ornamentals 0.005 1.88e 05/

1.88e 04 1.34e 06/

1.34e 05 0.004 1.63e 05/

1.63e 04 1.16e 06/

1.16e 05 Table B2: Occupational Handler, Cancer ( Q*) Risk from Oxadiazon at PPE Exposure Scenario # Crop Type Total PPE 1 Daily Dose ( mg/ kg/ day) a PPE 1 LADDb 3/ 30 days PPE 1 Riskc Total PPE 2 Daily Dose ( mg/ kg/ day) a PPE 2 LADDb 3/ 30 days PPE2 Riskc 51 Applying with a Rights of Way Sprayer ( 4) roadsides 0.890 3.66e 04/

3.66e 03 2.60e 05/

2.60e 04 0.069 2.82e 04/

2.82e 03 2.00e 05/

2.00e 04 Applying Wettable Powders for Handgun Applicators ( ORETF) ( 5) lawns, parks, recreational areas 0.019 7.83e 05/

7.83e 04 5.57e 06/

5.57e 05 0.010 4.13e 05/

4.13e 04 2.94e 06/

2.94e 05 Applying Granular with a Tractor Drawn Spreader ( 6) sod farms 0.008 1.16e 05/

1.16e 04 8.23e 07/

8.23e 05 0.0072 9.88e 06/

9.88e 05 7.03e 07/

7.03e 06 golf courses 0.004 5.79e 06/

5.79e 05 4.11e 07/

4.11e 06 0.0036 4.94e 06/

4.94e 05 3.51e 07/

3.51e 06 Mixer/ Loader/ Applicator Backpack Sprayer ( LCO) ( 7) lawns, golf courses, ornamentals nurseries 0.073 2.99e 04/

2.99e 03 2.13e 05/

2.13e 04 0.05 2.04e 04/

2.04e 03 1.45e 05/

1.45e 04 Low Pressure Handwand  Wettable Powder Formulations ( LCO)

( 8) lawns, golf courses, nursery stock 0.540 2.20e 03/

2.20e 03 1.56e 04/

1.56e 03 0.47 1.95e 03/

1.95e 02 1.38e 04/

1.38e 03 High Pressure Handwand  ( Wettable Powder Formulations) ( 9) woody ornamentals, conifer nurseries. 0.064 2.64e 04/

2.64e 03 1.88e 05/

1.88e 04 0.041 1.69e 04/

1.69e 03 1.20e 05/

1.20e 04 Lawn Handgun ( Wettable Powder Formulations) ( ORETF) ( 10) ornamentals, lawns, parks rec areas 0.036 1.49e 04/

1.49e 03 1.06e 05/

1.06e 04 0.027 1.13e 04/

1.13e 03 8.03e 06/

8.03e 05 Granulars with a Push Type Spreader ( ORETF) ( 11) l a wn s , g o l f c o u r s e s , p a r k s ,

recreational areas, ornamentals 0.006 2.54e 05/

2.54e 04 1.80e 06/

1.80e 05 No Data No Data No data Granulars with a Bellygrinder ( LCO) ( 12) golfcourses, parks, rec areas. 0.051 2.11e 04/

2.11e 03 1.50e 05/

1.50e 04 0.033 1.35e 04/

1.35e 03 9.60e 06/

9.60e 05 a PPE1, 2 Total Daily Dose = [ PPE Daily Dermal Exposure ( mg/ day) * Dermal absorption Factor ( 9%) + baseline Daily Inhalation Exposure ( mg/ day)]/ Body Weight ( 70 kg).

b PPE1, 2 LADD ( mg/ kg/ day) = PPE Total Daily Dose ( mg/ kg/ day) * ( Number of days exposed per year) / 365 days per year) * 35 years worked/ 70 year lifetime.

C PPE1, 2 Total Cancer Risk = PPE LADD ( mg/ kg/ day) * ( Q 1*), where Q 1* = 7.11e 2 ( mg/ kg/ day) 1.

PPE 1 cancer risk includes long pants, long shirts, gloves and no respirator.

PPE 2 cancer risk includes long pants, long shirts, double layer, gloves and no respirator.

Two exposure frequencies were used for cancer, the first represented the maximum number of applications per site per season to represent private use ( 3), and the second frequency applied a factor of ten to the first frequency to represent commercial handlers making multiple applications per site per season ( 30). 52 Table B3: Occupational Handler, Cancer ( Q*) Risk from Oxadiazon at PPE Exposure Scenario # Crop Type Total PPE 3 Daily Dose ( mg/ kg/ day) a PPE 3 LADDb 3/ 30 days PPE 3 Riskc Total PPE 4 Daily Dose ( mg/ kg/ day) a PPE 4 LADDb 3/ 30 days PPE 4 Riskc Mixer/ Loader Exposure Mixing/ Loading Wettable Powders for Chemigation Application ( 1a) sod farms 0.360 1.47e 03/

1.47e 02 1.05E 04/

1.05e 03 0.3 1.25e 03/

1.25e 02 8.90e 05/

8.90e 04 Mixing/ Loading Wettable Powders for Groundboom Application ( 1b) conifer nurseries, woody ornamentals 0.055 2.25e 04/

2.25e 03 1.60e 05/

1.60e 04 0.046 1.91e 04/

1.91e 03 1.36e 05/

1.36e 04 herbaceous ornamentals 0.041 1.68e 04/

1.68e 03 1.20e 05/

1.20e 04 0.035 1.43e 04/

1.43e 03 1.02e 05/

1.02e 04 sod farms 0.082 3.37e 04/

3.37e 03 2.39e 05/

2.39e 04 0.070 2.86e 04/

2.86e 03 2.03e 05/

2.03e 04 golf courses 0.055 2.25e 04/

2.25e 03 1.60e 05/

1.60e 04 0.046 1.91e 04/

1.91e 03 1.36e 05/

1.36e 04 Mixing/ Loading Wettable Powders for Rights of Way Sprayer ( 1c) roadside turf, ornamentals 0.055 2.25e 04/

2.25e 03 1.60e 05/

1.60e 04 0.046 1.91e 04/

1.91e 03 1.36e 05/

1.36e 04 Loading Granular formulations ( 2) sod farms, conifers forest 0.004 1.81e 05/

1.81e 04 1.28e 06/

1.28e 05 0.003 1.21e 05/

1.21e 04 8.63e 07/

8.63e 06 golf course turf, parks,

recreational areas 0.002 9.03e 06/

9.03e 05 6.42e 07/

6.42e 06 0.0015 6.07e 06/

6.07e 05 4.31e 07/

4.31e 06 woody ornamentals 0.002 9.03e 06/

9.03e 07 6.42e 07/

6.42e 06 0.0015 6.07e 06/

6.07e 05 4.31e 07/

4.31e 06 Applicator Applying with a Groundboom ( 3) sod farms 0.005 1.99e 05/

1.99e 04 1.41e 06/

1.41e 05 0.0039 1.61e 05/

1.61e 04 1.14e 06/

1.14e 05 herbaceous ornamentals 0.002 9.93e 06/

9.93e 05 7.06e 07/

7.06e 06 0.002 8.03e 06/

8.03e 05 5.71e 07/

5.71e 06 golf courses 0.003 1.32e 05/

1.32e 04 9.42e 07/

9.42e 06 0.003 1.07e 05/

1.07e 04 7.61e07/

7.61e 06 conifer nurseries, woody ornamentals 0.003 1.32e 05/

1.32e 04 9.42e07/

9.42e 06 0.003 1.07e 05/

1.07e 04 7.61e07/

7.61e 06 Table B3: Occupational Handler, Cancer ( Q*) Risk from Oxadiazon at PPE Exposure Scenario # Crop Type Total PPE 3 Daily Dose ( mg/ kg/ day) a PPE 3 LADDb 3/ 30 days PPE 3 Riskc Total PPE 4 Daily Dose ( mg/ kg/ day) a PPE 4 LADDb 3/ 30 days PPE 4 Riskc 53 Applying with a Rights of Way Sprayer ( 4) roadsides 0.082 3.37e 04/

3.37e 03 2.40e 05/

2.40e 04 0.061 2.52e 04/

2.52e 03 1.80e 05/

1.80e 04 Applying Wettable Powders for Handgun Applicators ( ORETF) ( 5) lawns, parks, recreational areas 0.019 7.74e 05/

7.74e 04 5.50e06/

5.50e 05 0.0098 4.04e 05/

4.04e 04 2.87e06/

2.87e 05 Applying Granular with a Tractor Drawn Spreader ( 6) sod farms 0.004 5.56e 06/

5.56e 05 3.95e07/

3.95e 06 0.0028 3.87e 06/

3.87e 05 2.75e07/

2.75e 06 golf courses 0.002 2.78e 06/

2.78e 05 1.98e07/

1.98e 06 0.0014 1.94e 06/

1.94e 05 1.38e07/

1.38e 06 Mixer/ Loader/ Applicator Backpack Sprayer ( LCO) ( 7) l a wn s , g o l f c o u r s e s ,

ornamentals nurseries 0.066 2.71e 04/

2.71e 03 1.93e 05/

1.93e 04 0.043 1.76e 04/

1.76e 03 1.25e05/

1.25e 04 Low Pressure Handwand  Wettable Powder Formulations ( LCO) ( 8) lawns, golf courses, nursery stock 0.280 1.17e 03/

1.17e 02 8.30e05/

8.30e 04 0.22 9.14e 04/

9.14e 03 6.50e05/

6.50e 04 High Pressure Handwand  ( Wettable Powder Formulations) ( 9) woody ornamentals, conifer nurseries. 0.068 2.79e 04/

2.79e 03 1.98e05/

1.98e 04 0.045 1.84e 04/

1.84e 03 1.31e05/

1.31e 04 Lawn Handgun ( Wettable Powder Formulations) ( ORETF) ( 10) ornamentals, lawns, parks rec areas 0.022 9.06e 05/

9.06e 04 6.44e 06/

6.44e 05 0.013 5.47e 05/

5.47e 04 3.89e06/

3.89e 05 Granulars with a Push Type Spreader ( ORETF) ( 11) lawns, golf courses, parks,

r e c r e a t iona l ar e a s ,

ornamentals 0.006 2.54e 05/

2.54e 04 1.80e06/

1.80e 05 No Data No Data No data Granulars with a Bellygrinder ( LCO) ( 12) golfcourses, pa rk s, rec areas. 0.049 1.99e 04/

1.99e 03 1.42e05/

1.42e 04 0.03 1.23e 04/

1.23e 03 8.77e06/

8.77e 05 a PPE 3,4 Total Daily Dose = [ PPE Daily Dermal Exposure ( mg/ day) * Dermal absorption Factor ( 9%)+ baseline Daily Inhalation Exposure ( mg/ day)]/ Body Weight ( 70 kg).

b PPE 3, 4 LADD ( mg/ kg/ day) = PPE Total Daily Dose ( mg/ kg/ day) * ( Number of days exposed per year) / 365 days per year) * 35 years worked/ 70 year lifetime.

C PPE 3, 4 Total Cancer Risk = PPE LADD ( mg/ kg/ day) * ( Q 1*), where Q 1* = 7.11e 2 ( mg/ kg/ day) 1.

PPE3 cancer risk includes long pants, long shirts, gloves and respirator.