Page 1 of 36 UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGTON, D. C. 20460 OFFICE OF PREVENTION, PESTICIDES AND TOXIC SUBSTANCES February 27, 2006 Memorandum:

SUBJECT: Didecyl Dimethyl Ammonium Chloride ( DDAC): Occupational and Residential Exposure Assessment for the Reregistration Eligibility Decision Document.

FROM: Matthew Lloyd, Industrial Hygienist Reregistration Branch   RRB1 Health Effects Division ( HED) ( 7509C)

THROUGH: Whang Phang, Branch Senior Scientist Reregistration Branch   RRB1 Health Effects Division ( HED) ( 7509C)

TO: Tracy Lantz, Regulatory Management Branch Antimicrobials Division ( AD) ( 7510C)

PC Code: 069149 DP Barcode: D326896 The attached assessment is the occupational and residential exposure and risk estimates for DDAC to support AD's reregistration eligibility decision ( RED) document. This exposure assessment was based on the toxicity endpoints selected by AD. The data analysis included in this assessment was prepared by Versar, Inc. under the supervision of HED. Page 2 of 36 Table of Contents Executive Summary................................................................................................................................................................................... 3 1.0 Occupational and Residential Exposure/ Risk Assessment ............................................................................................................ 6 1.1 Purpose...................................................................................................................................................................... 6 1.2 Criteria for Conducting Exposure Assessments................................................................................................... 6 1.3 Summary of Hazard Concerns for DDAC........................................................................................... 6 1.4 Incident Reports..................................................................................................................................................... 10 1.5 Summary of Physical and Chemical Properties of DDAC................................................................................ 11 1.6 Summary of Use Patterns and Formulations ..................................................................................................... 11 1.6.1 End Use Products ................................................................................................................. 11 1.6.2 Registered Use Categories and Sites................................................................................... 11 1.6.3 Application Methods ............................................................................................................ 12 2.0 Occupational Exposures and Risks................................................................................................................................................. 12 2.1 Occupational Handler Exposures and Risks...................................................................................................... 12 2.1.1 Data and Assumptions for Handler Exposure Scenarios ................................................ 14 <IP_ADDRESS> Assumptions for Handler Exposure Scenarios ............................................................. 14 <IP_ADDRESS> Exposure Data for Handler Exposure Scenarios ......................................................... 15 <IP_ADDRESS> DDAC Inhalation Handler Exposure Scenarios .......................................................... 15 2.1.2 DDAC Handler Exposure and Assessment ....................................................................... 16 <IP_ADDRESS> DDAC Handler Exposure and Risk Calculations........................................................ 16 <IP_ADDRESS> DDAC Risk Summary..................................................................................................... 17 2.1.3 Cancer DDAC Handler Exposure and Risk Assessment................................................. 19 2.1.4 Summary of Risk Concerns and Data Gaps for Occupational Handlers...................... 19 <IP_ADDRESS> Summary of Risk Concerns............................................................................................. 19 <IP_ADDRESS> Summary of Data Gaps ................................................................................................... 20 2.1.5 Recommendations For Refining Occupational Handler Risk Assessment.................... 20 2.2 Occupational Postapplication Exposures and Risks ......................................................................................... 20 2.2.1 Occupational Postapplication Exposure Scenarios.......................................................... 20 2.2.2 Data/ Assumptions for Postapplication Exposure Scenarios ........................................... 21 2.2.3 Occupational Postapplication Exposure and Risk Estimates ......................................... 22 2.2.4 Occupational Postapplication Exposure and Risk Estimates for Cancer ..................... 25 2.2.5 Summary of Occupational Postapplication Risk Concerns and Data Gaps................. 25 2.2.6 Recommendations for Refining Occupational Postapplication Risk Assessment ........ 25 3.0 Residential and Other Non Occupational Exposures and Risks ................................................................................................ 25 3.1 Residential Handler Exposures and Risks.......................................................................................................... 25 3.1.1 DDAC Dermal Handler Exposure Scenarios.................................................................... 26 3.1.2 Data and Assumptions for Handler Exposure Scenarios ................................................ 27 3.1.3 Residential Handler Exposure and Risk Estimates.......................................................... 27 3.1.4 Residential Handler Exposure and Risk Estimates for Cancer...................................... 31 3.1.5 Summary of Risk Concerns and Data Gaps for Handlers .............................................. 32 3.1.6 Recommendations for Refining Residential Handler Risk Assessment......................... 32 3.2 Residential Postapplication Exposures and Risks ............................................................................................. 32 3.2.1 Residential Postapplication Exposure Scenarios.............................................................. 32 3.2.2 Data and Assumptions for Residential Postapplication Exposure Scenarios............... 33 3.2.3 Residential Postapplication Exposure and Risk Estimates ............................................. 34 3.2.4 Residential Postapplication Exposure and Risk Estimates for Cancer ......................... 35 3.2.5 Summary of Residential Postapplication Risk Concerns and Data ............................... 36 Gaps......................................................................................................................................................................... 36 3.2.6 Recommendations for Refining Residential Postapplication Risk Assessments........... 36 List Of Appendices Appendix A   DDAC Occupational Handler Risk Calculations Appendix B   DDAC Agricultural and Residential Handler Risks Page 3 of 36 Executive Summary DDAC ( Group I Quat Cluster) is a group of structurally similar quaternary ammonium compounds (" quats"). Most of the registered uses of DDAC are classified as antimicrobial uses and will be assessed by the Antimicrobial Division in EPA= s Office of Pesticide Programs. This document is the occupational and residential exposure assessment for DDAC from its use as a plant growth regulator. In this document, the Agency presents the results of its review of the potential human health effects of occupational and residential/ non occupational exposure to DDAC.

Toxicological endpoints were selected for short term dermal, short and intermediate term inhalation, and incidental oral exposures to DDAC. There is a significant potential for exposure in a variety of occupational agricultural and commercial settings, as well as in residential settings. Therefore, risk assessments are required for occupational and residential handlers, as well as for occupational and residential postapplication exposures that can occur as a result of DDAC use.

The use patterns of DDAC can range from short term through intermediate term exposure durations. Endpoints were selected to address each of these durations. DDAC exposures are expected to occur to both occupational and residential users. The Agency selected a short term dermal endpoint for DDAC based on adverse dermal effects rather than systemic toxicity. The short term dermal NOAEL was 2 mg/ kg/ day and the LOAEL was 6 mg/ kg/ day, based on increased clinical and gross findings of the skin ( erythema, edema, exfoliation, excoriation, and ulceration). No intermediate or long term dermal endpoints were identified for DDAC. The short and intermediate term inhalation and short term incidental oral risk assessments for DDAC were based on a NOAEL of 10 mg/ kg/ day, which was chosen from a prenatal developmental toxicity study in rats. The LOAEL ( 20 mg/ kg/ day) was based largely on increased incidence of skeletal variations in females. Long term inhalation exposure to DDAC ( i. e., greater than 6 months) is not expected based on the use pattern of currently registered products. No cancer endpoint was identified.

The level of concern ( LOC) for occupational and non occupational DDAC dermal and inhalation exposures is a margin of exposure ( MOE) of less than 100. The MOE was based on 10x for interspecies extrapolation, and 10x for intraspecies variability. For calculating dermal exposure risk, no body weight is needed for the dermal endpoint, since no systemic dose is calculated ( i. e. the NOAEL of 0.15 µ g/ cm2 is used for risk assessment). Since the endpoint is female specific, the weight of 60 kilograms is used in the assessment. This represents the average body weight of an adult female.

DDAC is formulated as a soluble concentrate, emulsifiable concentrate, ready to use solution, pressurized liquid, wettable powder, and water soluble packet. There are many end use products that contain DDAC, and each label could not be reviewed to determine the formulationtype and the registered uses. Additionally, the Master Label does not indicate the formulation types that have been registered for individual use patterns. As a conservative approach, this chapter will assume that when used as a growth regulator, DDAC may be formulated as a liquid Page 4 of 36 concentrate, a water dispersible granular, and a wettable powder.

In occupational settings, DDAC is applied with several types of application equipment B including low pressure handwand sprayers, handgun sprayers ( high pressure handwand), watering cans, and pump trigger sprayers. DDAC dermal exposures and risks were not estimated for occupational handler exposures. Instead, dermal exposures and risks will be mitigated using default personal protective equipment requirements based on the toxicity of the end use product. To minimize dermal exposures, the minimum PPE required for mixers, loaders, and others exposed to end use products containing concentrations of DDAC that result in classification of category I or II for skin irritation potential will be long sleeve shirt, long pants, shoes, socks, chemical resistant gloves, and chemical resistant apron. The minimum PPE required for mixers, loaders, and others exposed to end use products containing concentrations of DDAC that result in classification of category III for skin irritation potential will be long sleeve shirt, long pants, shoes, socks, and chemical resistant gloves. Once diluted, if the concentration of DDAC in the diluted solution would result in classification of toxicity category IV for skin irritation potential, then the chemical resistant gloves and chemical resistant apron can be eliminated for applicators and others exposed to the dilute. Note that chemical resistant eye protection will be required if the end use product is classified as category I or II for eye irritation potential.

In all occupational handler scenarios, inhalation MOEs exceed 100 at baseline ( i. e., no respirator) and are not of concern. Since no dermal endpoint for systemic toxicological effects was selected, no dermal doses were estimated. Dermal and inhalation risks were not combined because the dermal endpoint ( adverse dermal effects) is different from the inhalation endpoint ( developmental effects).

DDAC can be used on ornamental crops in greenhouse and outdoor occupational settings. As a result, individuals can potentially be exposed by working in areas that have been previously treated. There is concern about the kinds of exposures one can encounter in the workplace after DDAC is applied to ornamentals. The following occupational postapplication risks are of concern until:

$ day 63 for all crops and all postapplication activities, assuming 400 gallons are applied per acre,

$ day 57 for all crops and all postapplication activities, assuming 200 gallons are applied per acre,

$ day 50 for all crops and all postapplication activities, assuming 100 gallons are applied per acre.

$ Inhalation exposures are thought to be negligible in outdoor postapplication scenarios, since DDAC has low vapor pressure, and the dilution factor in an outdoor environment is considered infinite. In addition, under the Worker Protection Standard for Agricultural Pesticides B WPS B ( 40 CFR 170) greenhouses must be appropriately ventilated ( ventilation criteria are provided in section 2.2.1) following pesticide applications so that postapplication inhalation exposures are minimal. As such, inhalation postapplication Page 5 of 36 exposures are not considered in this assessment.

It has been determined that there is a potential for exposure in residential settings during the application process for homeowners who use products containing DDAC. There is also a potential for exposure from entering DDAC treated areas, such as home gardens and greenhouses that could lead to exposures scenarios. Risk assessments have been completed for both residential handler and postapplication scenarios.

The NOAEL's for residential handler risks are based on 80% TGAI ( 4 µ g/ cm2). When the end use product is formulated with 10% or less of DDAC, one scenario for residential handlers is of concern. Mixing/ loading/ applying liquid concentrates with a hose end sprayer is of concern for ornamental plants at the 0.034 lb ai/ gal rate with an MOE of 68. When the end use product is formulated with more than 10% DDAC, the dermal risks for residential handlers are of concern for all DDAC residential handler scenarios where data are available ( MOEs < 1). The short term inhalation risks for residential handlers are not of concern for any residential uses of DDAC.

Short term MOEs were calculated for adults performing tasks in home greenhouses and gardens following applications of DDAC. Cancer risks were not calculated, since no toxicological endpoint for cancer was selected. In residential settings, HED does not use restricted entry intervals or other mitigation approaches to limit postapplication exposures, because they are viewed as impractical and not enforceable. As such, risk estimates on the day of application are the key concern. In the assessment for residential postapplication exposure, there are risk concerns for DDAC as currently used in a residential environment ( MOEs < 1). Page 6 of 36 1.0 Occupational and Residential Exposure/ Risk Assessment 1.1 Purpose DDAC ( Group I Quat Cluster) is a group of structurally similar quaternary ammonium compounds (" quats") that are characterized by having a positively charged nitrogen covalently bonded to two alkyl group substituents ( at least one C8 or longer) and two methyl substituents. In finished form, these quats are salts with the positively charged nitrogen ( cation) balanced by a negatively charged molecule ( anion). The anion for the quats in this cluster is chloride or bromide. Most of the registered uses of DDAC are classified as antimicrobial uses and will be assessed by the Antimicrobial Division in EPA= s Office of Pesticide Programs.

This document is the occupational and residential exposure assessment for DDAC from its use as a plant growth regulator. In this document, the Agency presents the results of its review of the potential human health effects of occupational and residential/ nonoccupational exposure to DDAC.

1.2 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 a potential for exposure to handlers ( mixers, loaders, applicators) during use or to persons entering treated sites or exposed to vapors after application is complete. Toxicological endpoints were selected for short term dermal, short and intermediate term inhalation, and incidental oral exposures to DDAC. There is a significant potential for exposure in a variety of occupational agricultural and commercial settings as well as in residential settings. Therefore, risk assessments are required for occupational and residential handlers as well as for occupational and residential postapplication exposures that can occur as a result of DDAC use.

1.3 Summary of Hazard Concerns for DDAC The toxicological endpoints used to complete the occupational and residential risk assessment were based on the best professional judgement of EPA toxicologists. Adverse effects were identified at durations of exposure ranging from short term ( up to 30 days) to intermediateterm durations (> 30 days up to 6 months) and long term durations (> 6 months). No cancer endpoint was identified; therefore, cancer risks were not assessed.

DDAC is a plant growth regulator. The use patterns can range from short term through intermediate term exposure durations. Endpoints were selected to address each of these durations of exposure. DDAC exposures are expected to occur to both occupational and residential users.

Dermal Route Page 7 of 36 No short or intermediate term dermal endpoint for systemic effects was selected for DDAC, since no systemic effects were identified at the limit dose of 1000 mg/ kg/ day of a diluted end use product containing 0.13% active ingredient ( ai). However, a short term dermal endpoint was identified for DDAC based on adverse dermal effects. The short term dermal NOAEL was 2 mg/ kg/ day which is equivalent to 0.15 µ g/ cm2) was determined from a LOAEL of 6 mg/ kg/ day based on increased clinical and gross findings of the skin ( erythema, edema, exfoliation, excoriation, and ulceration). The Agency did not select intermediate or long term dermal endpoints for DDAC.

Inhalation Route The short and intermediate term inhalation risk assessment for DDAC is based on an NOAEL of 10 mg/ kg/ day, derived from a prenatal developmental toxicity study in rats. The oral LOAEL ( 20 mg/ kg/ day) was based largely on increased incidence of skeletal variations in females. Long term inhalation exposure to DDAC ( i. e., greater than 6 months) is not expected for current registered uses. It was assumed that inhalation absorption is equivalent to oral absorption ( i. e. 100%).

Incidental Oral Route The short term incidental oral risk assessment for DDAC is based on a NOAEL of 10 mg/ kg/ day, derived from a prenatal developmental toxicity study in rats. The LOAEL ( 20 mg/ kg/ day) was based largely on increased incidence of skeletal variations in females, and the FQPA factor was 1x.

Level of Concern ( LOC)

The level of concern ( LOC) for occupational and non occupational DDAC dermal and inhalation exposures is an MOE of less than 100. The MOE was based on 10x for interspecies extrapolation, and 10x for intraspecies extrapolation.

Body Weight For calculating dermal exposure, body weight was not needed for the dermal endpoint, since no systemic dose was calculated. Section 3.1.1 contains a detailed description of this logic. Since the toxicological endpoint for inhalation is female specific, a body weight of 60 kilograms is used in the assessment. This represents the average body weight of an adult female.

Aggregation The dermal and inhalation margins of exposure were not combined for the DDAC risk assessment because the toxicity endpoints for the dermal and inhalation routes of exposure were Page 8 of 36 based on different toxicological effects.

Cancer No cancer endpoint was identified.

Acute Toxicity DDAC is corrosive and is of moderate acute toxicity by oral, dermal, or inhalation routes of exposure. DDAC is a severe eye irritant. DDAC is a weak dermal sensitizer. The acute toxicity data for DDAC are summarized below in Table 1 ( USEPA, 2006).

Table 1. Acute Toxicity Profile for DDAC Guideline No. Study Type MRID #( S). Results Toxicity Category 81 1 Acute Oral 41394404 LD50 (   ) = 331mg/ kg; LD50(   ) = 238mg/ kg; LD50 ( combined) = 262 mg/ kg II 81 2 Acute Dermal 42053801 LD50 (   ) = 3140mg/ kg; LD50 (   ) = 2730mg/ kg; LD50 ( combined) = 2930 mg/ kg III 81 3 Acute Inhalation 00145074 LC50 = between 0  0.7mg/ L II 81 4 Primary Eye Irritation 41394404 Severe eye irritant I 81 5 Primary Skin Irritation 41891405 Severe dermal irritant I 81 6 Dermal Sensitization 00160084 Slight sensitization Page 9 of 36 Table 2. Toxicological Endpoints of Concern for DDAC Exposure Scenario Dose Used in Risk Assessment ( mg/ kg/ day) Target MOE/ UF, Special FQPA SF for Risk Assessment Study and Toxicological Effects NOAEL ( developmental) = 10 mg/ kg/ day FQPA SF = 1 UF = 100 ( 10x inter species extrapolation, 10x intraspecies variation) Prenatal Developmental Toxicity  Rat MRID 41886701 LOAEL = 20 mg/ kg/ day based on increased incidence of skeletal variations. Acute Dietary ( Females 13 50)

Acute RfD = 0.1 mg/ kg/ day ( for Females age 13 50)

NOAEL = 10 mg/ kg/ day FQPA SF = 1 UF = 100 ( 10x inter species extrapolation, 10x intraspecies variation Chronic Toxicity Study  Dog MRID 41970401 LOAEL = 20 mg/ kg/ day based on decreased total cholesterol levels in females. Chronic Dietary ( general population)

Chronic RfD = 0.1 mg/ kg/ day Non Dietary Exposures Incidental Oral Short Term NOAEL ( developmental) = 10 mg/ kg/ day Target MOE = 100 ( 10x inter species extrapolation, 10x intra species variation) FQPA SF = 1 Prenatal Developmental Toxicity  Rat MRID 41886701 LOAEL = 20 mg/ kg/ day based on increased incidence of skeletal variations.

Incidental Oral Intermediate Term NOAEL = 10 mg/ kg/ day Target MOE = 100 ( 10x inter species extrapolation, 10x intra species variation) FQPA SF = 1 Chronic Toxicity Study  Dog MRID 41970401 LOAEL = 20 mg/ kg/ day based on decreased total cholesterol levels in females.

Dermal, Short term ( formulated product, 0.13% ai) No endpoint identified. No dermal or systemic effects identified in the 21 day dermal toxicity study ( MRID 45656601) up to and including the limit dose of 1000 mg/ kg/ day Dermal, Short term ( formulated product, 6% a. i.) NOAEL= 500 mg/ kg/ day ( 7750 µ g/ cm2) a Target MOE = 100 ( 10x inter species extrapolation, 10x intra species variation) 21 day dermal toxicity guinea pigs MRID 41105801 LOAEL = 1000 mg/ kg/ day, based on denuded nonvascularized epidermal layer. Page 10 of 36 Table 2. Toxicological Endpoints of Concern for DDAC Exposure Scenario Dose Used in Risk Assessment ( mg/ kg/ day) Target MOE/ UF, Special FQPA SF for Risk Assessment Study and Toxicological Effects Dermal, Short term ( TGAI 80%) NOAEL( dermal) = 2 mg/ kg/ day ( 4.0 Fg/ cm2) b Target MOE = 100 ( 10x inter species extrapolation, 10x intra species variation) 90 day Dermal Toxicity  Rat MRID 41305901 LOAEL = 6 mg/ kg/ day based on increased clinical and gross findings ( erythema, edema, exfoliation, excoriation, and ulceration)

Dermal, Intermediate and Long term ( formulated product) No appropriate endpoint identified.

Inhalation, Short Term NOAEL = 10 mg/ kg/ day Target MOE = 100 ( 10x inter species extrapolation, 10x intra species variation) c FQPA SF = 1 Prenatal Developmental Toxicity  Rat MRID 41886701 LOAEL = 20 mg/ kg/ day based on increased incidence of skeletal variations.

Inhalation, Intermediate and Long Term NOAEL = 10 mg/ kg/ day Target MOE = 100 ( 10x inter species extrapolation, 10x intra species variation) c FQPA SF = 1 Chronic Toxicity Study  Dog MRID 41970401 LOAEL = 20 mg/ kg/ day based on decreased total cholesterol levels in females.

a Formulated based dermal endpoint = ( 500 mg/ kg guinea pig x 0.4 kg guinea pig x 1000 ug/ mg) / 25.8 cm2 area treated = 7,750 µ g/ cm2 . b TGAI based dermal endpoint = ( 2 mg/ kg rat x 0.2 kg rat x 1000 ug/ mg) / 100 cm2 area treated = 4 µ g/ cm2 . C an additional uncertainty factor of 10x is used for route extrapolation from an oral endpoint.

1.4 Incident Reports The incident report is being prepared under a separate memo by Jonathan Chen, of the Office of Pesticide Programs. Page 11 of 36 1.5 Summary of Physical and Chemical Properties of DDAC The following table shows physical/ chemical characteristics that have been reported for DDAC.

Table 3. Physical/ Chemical Properties of DDAC Parameter DDAC Molecular Weight 362.08 Density 0.9216 g/ cm3 at 25 C Boiling Point NA Water Solubility Completely soluble Vapor Pressure 2.33E 11 mmHg 1.6 Summary of Use Patterns and Formulations 1.6.1 End Use Products DDAC ( Group I Quat Cluster) is a group of structurally similar quaternary ammonium compounds (" quats"). It is used in agricultural, commercial, and residential settings. DDAC is formulated as a soluble concentrate, emulsifiable concentrate, ready to use solution, pressurized liquid, wettable powder, water soluble packet, and impregnated material. Note that there are many end use products that contain DDAC and each label could not be reviewed to determine the formulation type and the registered uses. Also note that the Master Label does not indicate the formulation types registered for individual use patterns. Therefore, as a conservative approach, this chapter will assume that when used as a growth regulator, DDAC may be formulated as a liquid concentrate, a water dispersible granular, and a wettable powder.

1.6.2 Registered Use Categories and Sites An analysis of the current labeling and available use information was completed by the Antimicrobial Division. DDAC is registered for use in a variety of occupational and residential scenarios and thus both occupational and residential populations could be potentially exposed while performing DDAC applications. It is also possible for occupational and residential populations to be exposed to DDAC during postapplication time periods. Table 4 provides a summary of the maximum application rates, equipment, and amounts handled daily for registered DDAC uses. Page 12 of 36 Table 4: Summary of Maximum Application Rates for Registered DDAC Agricultural, Commercial, and Residential Uses Crop Target Maximum Application Rate Formulation Application Equipment Amount Handled Daily low pressure handwand sprayer 40 gallonsa 5 gallonsb handgun sprayer ( high pressure handwand) 1000 gallonsa 100 gallonsb Hose end sprayer 100 gallons Liquid Concentrate, Wettable Powder, Water Dispersible Granule watering can 5 gallons Ornamental Plants Foliage Spray or Soil Drench 0.034 lb ai/ gal Ready to use liquid pump trigger sprayer 1 gallon a   occupational rate b   residential rate All other amounts indicate dual use rate.

1.6.3 Application Methods DDAC is applied with several types of application equipment B including low pressure handwand sprayers, handgun sprayers ( high pressure handwand), watering cans, and pumptrigger sprayers.

2.0 Occupational Exposures and Risks There is a potential for exposure to DDAC in occupational scenarios from handling DDAC products during the application process ( i. e., mixer/ loaders, applicators, and mixer/ loader/ applicators) and a potential for postapplication worker exposure from entering into areas previously treated with DDAC. As a result, risk assessments have been completed for occupational handler scenarios as well as occupational postapplication scenarios.

2.1 Occupational Handler Exposures and Risks 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 target being treated, and the level of protection used by a handler can cause exposure levels to differ in a manner specific to each application event.

HED uses exposure scenarios to describe the various types of handler exposures that may Page 13 of 36 occur for a specific active ingredient. The use of scenarios as a basis for exposure assessment is very common as described in the U. S. EPA Guidelines for Exposure Assessment ( U. S. EPA; Federal Register Volume 57, Number 104; May 29, 1992). Information from the current labels, use and usage information, toxicology data, and exposure data were all key components in the development of the exposure scenarios. HED has developed a series of general descriptions for tasks that are associated with pesticide applications. Tasks associated with occupational pesticide handlers are categorized using one of the following terms:

$ Mixers and/ or Loaders: These individuals perform tasks in preparation for an application. For example, prior to application, mixer/ loaders would mix the DDAC and load it into the holding tank of the airplane or groundboom.

$ Applicators: These individuals operate application equipment during the release of a pesticide product into the environment. These individuals can make applications using equipment such as airplanes or groundboom.

$ Mixer/ Loader/ Applicators and or 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 transfer DDAC into the application equipment and then also apply it.

A chemical can produce different effects based on how long a person is exposed, how frequently exposures occur, and the level of exposure. HED classifies exposures up to 30 days as short term and exposures greater than 30 days up to several months as intermediate term. HED completes both short and intermediate term assessments for occupational scenarios in essentially all cases, because these kinds of exposures are likely and acceptable use/ usage data are not available to justify deleting intermediate term scenarios. Based on use data and label instructions, HED believes that occupational DDAC exposures may occur over a single day or up to weeks at a time for many use patterns and that intermittent exposure over several weeks also may occur. Some applicators may apply DDAC over a period of weeks, because they are custom or commercial applicators who are completing multiple applications for a number of different clients. Long term handler exposures are not expected to occur for DDAC.

Other parameters are also defined from use and usage data such as application rates and application frequency. HED typically completes risk assessments using maximum application rates for each in order to ensure there are no concerns for each specific use.

Occupational handler exposure assessments are completed by the Angency using different levels of risk mitigation. Typically, HED uses a tiered approach. The lowest tier is designated as the baseline exposure scenario ( i. e., no respirator). If risks are of concern at baseline attire, then increasing levels of personal protective equipment or PPE ( e. g., respirators) are evaluated. If risks remain of concern with maximum PPE, then engineering controls ( e. g., enclosed cabs, water soluble packaging, and closed mixing/ loading systems) are evaluated. This approach is used to ensure that the lowest level of risk mitigation that provides adequate protection is Page 14 of 36 selected, since the addition of PPE and engineering controls involves an additional expense to the user and B in the case of PPE B also involves an additional burden to the user due to decreased comfort and dexterity and increased heat stress and respiratory stress.

2.1.1 Data and Assumptions for Handler Exposure Scenarios <IP_ADDRESS> Assumptions for Handler Exposure Scenarios A series of assumptions and exposure factors served as the basis for completing the occupational handler risk assessments. Each assumption and factor is detailed below on an individual basis. The assumptions and factors used in the risk calculations include:

$ Occupational handler exposure estimates were based on surrogate data from: ( 1) the Pesticide Handlers Exposure Database ( PHED) and ( 2) the Outdoor Residential Exposure Task Force ( ORETF).

$ The toxicological endpoint of concern for dermal risks is from a dermal study; with the effects being irritation ( no systemic effects were observed). Therefore, no dose is calculated and no body weight is used to complete the dermal exposure assessment. The toxicological endpoint of concern for inhalation risks is from a prenatal developmental toxicity study; with the effects seen in females; therefore, the average body weight of an adult female ( i. e., 60 kg) is used to complete the inhalation exposure assessment.

$ Generic protection factors ( PFs) were used to calculate exposures when data were not available. For example, an 80 percent protection factor was assumed for the use of a respirator equipped with a quarter face dust/ mist filter.

$ Exposure factors used to calculate daily exposures to handlers are based on applicable data, if available. For lack of appropriate data, values from a scenario deemed similar enough by the assessor might be used. For example, ORETF data for hose end sprayers is used as a surrogate for inhalation unit exposures for mixing/ loading/ applying with a sprinkling can.

$ The Agency typically assumes the maximum application rates allowed by labels in its risk assessments ( see Table 4).

$ The average occupational workday is assumed to be 8 hours.

$ The daily areas treated were defined for each handler scenario ( in appropriate units) by determining the amount that can be reasonably treated in a single day ( e. g., gallons per day). When possible, the assumptions for daily areas treated are taken from the Health Effects Division Science Advisory Committee on Exposure SOP # 9: Standard Values for Daily Acres Treated in Agriculture, completed in July, 2000. However, no standard values are available for numerous scenarios. Assumptions for these scenarios are based on Page 15 of 36 HED estimates and could be further refined from input from affected sectors.

There are data gaps that have been identified for some DDAC applications. Each is identified in the calculation tables and is also noted in the summary of risk calculations.

<IP_ADDRESS> Exposure Data for Handler Exposure Scenarios Exposure analyses were performed using the Pesticide Handlers Exposure Database ( PHED) as tabulated in the PHED Surrogate Exposure Guide of August 1998. A description of PHED is included in Appendix A. The unit exposures calculated by PHED generally range from the geometric mean to the median of the selected data set. The assessment of data quality is based on the number of observations and the available quality control data. 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.

Unit exposures values have been taken from both the Pesticide Handler Exposure Database ( PHED) and studies provided by the Outdoor Residential Exposure Task Force ( ORETF) where the scenario unit exposure values are more applicable. Appendix A contains background information on PHED and ORETF.

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 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 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 Abest fit@ exposure value representing the entire body.

ORETF Handler Studies ( MRID 449722 01): A report was submitted by the ORETF ( Outdoor Residential Exposure Task Force) that presented data in which the application of various products used on turf by homeowners and lawncare operators ( LCOs) was monitored. All of the data submitted in this report were completed in a series of studies. The study that monitored LCO exposure scenarios using a low pressure, high volume turf handgun ( ORETF Study OMA002) is summarized in Appendix A as is the study that monitored homeowner exposures while using a hose end sprayer ( ORETF Study OMA004).

<IP_ADDRESS> DDAC Inhalation Handler Exposure Scenarios It has been determined that exposure to pesticide handlers is likely during the occupational use of DDAC in a variety of occupational environments. The anticipated use patterns and current Page 16 of 36 labeling indicate several occupational exposure scenarios based on the types of equipment and techniques that can potentially be used for DDAC applications.

DDAC inhalation exposure was estimated using PHED or ORETF data. Risks were calculated by comparing the inhalation dose to the short and intermediate term NOAEL to determine the Margin of Exposure ( MOE).

DDAC dermal exposures and risks were not estimated for occupational handler exposures. Instead, dermal exposures and risks will be mitigated using default personal protective equipment requirements based on the toxicity of the end use product. To minimize dermal exposures, the minimum PPE required for mixers, loaders, and others exposed to end use products containing concentrations of DDAC that result in classification of category I or II for skin potential will be long sleeve shirt, long pants, shoes, socks, chemical resistant gloves, and chemical resistant apron. The minimum PPE required for mixers, loaders, and others exposed to end use products containing concentrations of DDAC that result in classification of category III for skin potential will be long sleeve shirt, long pants, shoes, socks, and chemical resistant gloves. Once diluted, if the concentration of DDAC in the diluted solution would result in classification of toxicity category IV for skin potential, then the chemical resistant gloves and chemical resistant apron can be eliminated for applicators and others exposed to the dilute. Note that chemical resistant eye protection will be required if the end use product is classified as category I or II for eye irritation potential.

The quantitative inhalation exposure assessment developed for occupational handlers is based on the following scenarios. [ Note: The scenario numbers correspond to the tables of risk calculations included in the occupational risk calculation aspects of the appendices.]

Mixer/ Loader/ Applicators: ( 1) Liquid Formulations: Low Pressure Handwand Sprayer ( ORETF data) ( 2) Wettable Powder Formulations: Low Pressure Handwand Sprayer ( PHED data) ( 3) Water Dispersible Granules with Low Pressure Handwand ( using liquids ORETF data) ( 4) Liquid Formulations: Handgun Sprayer ( ORETF data) ( 5) Wettable Powders with a Handgun Sprayer ( ORETF data) ( 6) Water Soluble Bags with Handgun Sprayer ( ORETF data) ( 7) Dry Flowables Concentrates with a Handgun Sprayer ( ORETF data) ( 8) Liquid Formulations: Sprinkling Can ( ORETF hose end data) ( 9) Liquid Formulations: Ready to Use Pump Trigger Sprayer ( ORETF data)

2.1.2 DDAC Handler Exposure and Assessment <IP_ADDRESS> DDAC Handler Exposure and Risk Calculations Handler risks ( i. e. MOEs) were calculated as described in Appendix A. The basic rationale for these calculations is that the daily exposure is the product of the amount of ai handled per day times a unit exposure value. The MOEs were calculated for short/ intermediate Page 17 of 36 term dermal and inhalation exposures. These MOEs were calculated separately because the dermal and inhalation endpoints were based upon different effects. A MOE greater than 100 indicates the risk is not of concern for that scenario.

<IP_ADDRESS> DDAC Risk Summary The short and intermediate term risks for each inhalation exposure scenario are presented in Table 5 and details are presented in Appendix B.

Short and Intermediate term Inhalation Risks In all occupational handler scenarios, inhalation MOEs are not of concern at baseline ( i. e., no respirator). In the case that the MOE is below 1000, the Agency may request a confirmatory inhalation toxicity study according to AD's policy ( oral communication from Tim Leighton).

Short and Intermediate term Total Risks Since no dermal endpoint for systemic toxicological effects was selected, no dermal exposure was estimated. Therefore, no combined dermal and inhalation risks were calculated. Page 18 of 36 Table 5: Short and Intermediate Term Inhalation Exposures and Risks to Occupational Handlers Exposure Scenario Application Ratea ( lb ai/ gallon) Area Treated Dailyb ( gallons) Baseline Inhalation Unit Exposurec ( ug/ lb ai) Baseline Inhalation Exposure ( mg/ day) Baseline Inhalation Dose ( mg/ kg/ day) Baseline Inhalation MOE Mixer/ Loader/ Applicator Mixing/ Loading/ Applying ( M/ L/ A) Liquid Concentrates with Low Pressure ( LP) Handwand ( 1) 0.034 40 2.7 0.0037 0.000061 160000 M/ L/ A Wettable Powders ( WP) with LP Handwand ( 2) 0.034 40 1100 1.5 0.025 400 M/ L/ A Water Dispersible Granules ( WDG) with LP Handwand ( liquid concentrate ORETF data as surrogate) ( 3) 0.034 40 2.7 0.0037 0.000061 160000 M/ L/ A Liquid Concentrates with a Handgun Sprayer ( 4) 0.034 1000 1.5 0.051 0.00085 12000 M/ L/ A WP with a Handgun Sprayer ( 4) 0.034 1000 64 2.2 0.036 280 M/ L/ A WSB with Handgun Sprayer ( 5) 0.034 1000 7.2 0.24 0.0041 2500 M/ L/ A Dry Flowables Concentrates ( DF) with a Handgun Sprayer ( 6) 0.034 1000 22 0.75 0.012 800 M/ L/ A Liquids with a Watering Can ( 7) 0.034 5 17 0.0029 0.000048 210000 a Application rates are the maximum application rates determined from the EPA Master Label provided for DDAC from AD b Amount handled per day values are HED estimates of gallons applied per day based on Exposure SAC SOP # 9 A Standard Values for Daily Acres Treated in Agriculture,@ industry sources, and HED estimates.

c Baseline Inhalation: no respirator.

d Baseline inhalation exposure ( mg/ day) = application rate ( lb ai/ gal ) x amount handled per day ( gal/ day) x baseline inhalation unit exposure ( µ g/ lb ai) x conversion factor from µ g to mg ( 0.001)

e Baseline inhalation dose ( mg/ kg/ day) = baseline inhalation exposure ( mg/ day) x inhalation absorption factor ( 100%) / female bodyweight ( 60 kg)

f Inhalation MOE = inhalation NOAEL ( 10 mg/ kg/ day) / baseline inhalation dose ( mg/ kg/ day) Page 19 of 36 2.1.3 Cancer DDAC Handler Exposure and Risk Assessment No cancer endpoints were identified for DDAC; therefore, cancer risks to handlers were not assessed.

2.1.4 Summary of Risk Concerns and Data Gaps for Occupational Handlers There are no occupational handler scenarios for DDAC that have inhalation risks associated with them that are above the Agency's level of concern for risk assessments. However, there are some occupational handler scenarios for DDAC that are data gaps because of lack of unit exposure data.

<IP_ADDRESS> Summary of Risk Concerns The short and intermediate term inhalation handler risk assessment for DDAC indicates no risk concerns for occupational handler scenarios at baseline ( no respirator). See Section <IP_ADDRESS> for a detailed summary.

Three scenarios fall below an inhalation MOE of 1000 at the maximum level of mitigation, and the Agency may request a confirmatory inhalation toxicity study:   Mix/ Load/ Apply wettable powders with low pressure handwand ( MOE   400)   Mix/ Load/ Apply wettable powders with handgun sprayer ( high pressure handwand) ( MOE   280)   Mix/ Load/ Apply dry flowables with high pressure handwand ( MOE   800)

DDAC dermal exposures and risks were not estimated for occupational handler exposures. Instead, dermal exposures and risks will be mitigated using default personal protective equipment requirements based on the toxicity of the end use product. To minimize dermal exposures, the minimum PPE required for mixers, loaders, and others exposed to end use products containing concentrations of DDAC that result in classification of category I or II for skin irritation potential will be long sleeve shirt, long pants, shoes, socks, chemical resistant gloves, and chemicalresistant apron. The minimum PPE required for mixers, loaders, and others exposed to end use products containing concentrations of DDAC that result in classification of category III for skin irritation potential will be long sleeve shirt, long pants, shoes, socks, and chemical resistant gloves. Once diluted, if the concentration of DDAC in the diluted solution would result in classification of toxicity category IV for skin irritation potential, then the chemical resistant gloves and chemical resistant apron can be eliminated for applicators and others exposed to the dilute. Note that chemical resistant eyewear will be required if the end use product is classified as category I or II for eye irritation potential. Page 20 of 36 <IP_ADDRESS> Summary of Data Gaps Two data gaps were identified for DDAC:

$ mixing/ loading/ applying dry flowables using a low pressure handwand sprayer ( data for liquid formulations was used as a surrogate), and $ mixing/ loading/ applying liquid concentrates for sprinkling can ( ORETF data for hose end sprayers was used as a surrogate).

2.1.5 Recommendations For Refining Occupational Handler Risk Assessment In order to refine this occupational risk assessment, data on actual use patterns including rates, timing, and areas treated would better characterize DDAC risks. Exposure studies for many equipment types that lack data or that are not well represented in PHED ( e. g., because of low replicate numbers or data quality) should also be considered based on the data gaps identified above and based on a review of the quality of the data used in this assessment.

2.2 Occupational Postapplication Exposures and Risks HED uses the term " postapplication" to describe exposures to individuals that occur as a result of being in an environment that has been previously treated with a pesticide ( also referred to as reentry exposure). HED believes that there are distinct job functions or tasks related to the kinds of activities that occur in previously treated areas. Job requirements ( e. g., the kinds of jobs to cultivate a crop), the nature of the crop or target that was treated, and how the chemical residues degrade in the environment can cause exposure levels to differ over time. Each factor has been considered in this assessment.

2.2.1 Occupational Postapplication Exposure Scenarios DDAC can be used on ornamental crops in greenhouse and outdoor occupational settings. As a result, individuals can potentially be exposed by working in areas that have been previously treated. HED is concerned about the kinds of exposures one can receive in the workplace after DDAC is applied to ornamentals.

Since no toxicological endpoint was identified for dermal systemic adverse effects, no postapplication occupational exposures and risks were assessed using the traditional method of transfer coefficients specific to activities performed. Instead, a dermal endpoint was identified and expressed as µ g/ cm2. Postapplication dermal risks were assessed by:

$ converting the application rate from lb ai/ A to µ g/ cm2;

$ using HED= s default assumption that 20 percent of the initial application is available for transfer on day 0 ( i. e., 12 hours after application);

$ using HED= s default assumption that the residue dissipates at a rate of 10 percent Page 21 of 36 per day;

$ assuming that during the exposure period the skin repeatedly contacts foliar surfaces until a concentration of residues on the hand is equal to the concentration of residues on foliar surfaces, and thereafter, a steady state is achieved whereby the concentration on the hands remains the same as the concentration on the foliar surfaces.

Inhalation exposures are thought to be negligible in outdoor postapplication scenarios, since DDAC has low vapor pressure and the dilution factor in an outdoor environment is considered infinite. In addition, under the Worker Protection Standard for Agricultural Pesticides B WPS B ( 40 CFR 170) greenhouses must be appropriately ventilated ( ventilation criteria are provided) following pesticide applications so that postapplication inhalation exposures are minimal. As such, inhalation postapplication exposures are not considered in this assessment. However, HED recommends that WPS ventilation criteria be imposed on non WPS applications indoors in settings such as an atrium, interiorscape, or other commercial plant setting. The WPS ventilation requirements are:

$ 10 air exchanges, or $ 2 hours of mechanical ventilation ( i. e., fans), or $ 4 hours of passive ventilation ( i. e., windows, vents), or $ 11 hours of no ventilation followed by 1 hour of mechanical ventilation, or $ 11 hours of no ventilation followed by 2 hours of passive ventilation, or $ 24 hours of no ventilation In agricultural crop settings, the use of personal protective equipment or other types of equipment to mitigate postapplication exposures to workers is not considered a viable alternative for the regulatory process. This is described in some detail in the WPS. Instead, an administrative approach B a Restricted Entry Interval or REI B is used to mitigate postapplication risks following applications to crops. The REI is the period following a pesticide application during which entry into the treated area is restricted. Postapplication risk levels are generally calculated in the risk assessment process on a chemical, crop, and activity specific basis. To establish REIs, HED considers postapplication risks on varying days after application.

2.2.2 Data/ Assumptions for Postapplication Exposure Scenarios A series of assumptions and exposure factors served as the basis for completing the occupational postapplication worker risk assessments. Each assumption and factor is detailed below on an individual basis.

$ Maximum application rates were considered.

$ Levels of Concern: HED has established levels of concern ( LOC) for occupational postapplication risks B margins of exposure of less than 100 for occupational dermal risks are considered of concern. Page 22 of 36 $ Dislodgeable Foliar Residues: No DDAC specific dislodgeable foliar residue ( DFR) data were available. Therefore, this assessment uses HED= s default assumption that 20 percent of the application rate is available on day 0 ( i. e., 12 hours after application) and the residue dissipates at a rate of 10 percent per day.

$ Application rates are provided on the label only in terms of pounds active ingredient per gallon of spray. No information is provided for pounds active ingredient applied per acre. Postapplication assessments rely on the amount of active ingredient applied per unit area. To complete the postapplication occupational risk assessment for DDAC, a rangefinder was used based on gallons per acre that are often used in agriculture. Risks were assessed based on a rangefinder of gallons of dilute spray that might be applied per acre. The rangefinder includes: 400 gallons per acre ( as might be used in drench scenarios), 200 gallons per acre, and 100 gallons per acre.

2.2.3 Occupational Postapplication Exposure and Risk Estimates Occupational risks were calculated using a Margin of Exposure ( MOE), which is a ratio of the daily exposure to the toxicological endpoint of concern. Postapplication risks diminish over time because DDAC residues eventually dissipate in the environment. As a result, risks were calculated over time based on changing residue levels. Postapplication exposure ( i. e. MOEs) were calculated as described in Appendix A.

Postapplication Risk Summary A summary of the postapplication risks are provided in Table 6 and details are presented in Appendix B. The occupational postapplication exposure and risk assessment for ornamental crop uses of DDAC indicates that dermal risks are of concern until:

$ day 63 for all crops and all postapplication activities, assuming 400 gallons are applied per acre,

$ day 57 for all crops and all postapplication activities, assuming 200 gallons are applied per acre,

$ day 50 for all crops and all postapplication activities, assuming 100 gallons are applied per acre. Page 23 of 36 Table 6: Dermal Risks to Occupational Postapplication Workers Day After Exposure Daily residue dissipation percent ( minus 10% after day 0) Residue Concentration on Skinc ( ug/ cm2) Dermal MOEd Handling treated ornamental plants, Spray Formulation 0.034 lb ai/ gal, assuming 400 gallons per acre, 20% initial default transferable residue, 31 ug/ cm2 DFR on day 0.

0 ( 12 hours) 0% 31 < 1 1 ( 24 hours) 10% 27 < 1 10 ( days) 10% 11 < 1 20 10% 3.7 1 30 10% 1.3 3 40 10% 0.45 9 50 10% 0.16 25 60 10% 0.055 73 61 10% 0.049 81 62 10% 0.044 90 63 10% 0.04 100 Handling treated ornamental plants, Spray Formulation 0.034 lb ai/ gal, assuming 200 gallons per acre, 20% initial default transferable residue, 15 ug/ cm2 DFR on day 0.

0 ( 12 hours) 0% 15 < 1 1 ( 24 hours) 10% 14 < 1 10 ( days) 10% 5.3 1 20 10% 1.9 2 30 10% 0.65 6 40 10% .23 18 50 10% 0.079 51 55 10% 0.046 86 56 10% 0.042 96 57 10% 0.038 110 Page 24 of 36 Table 6: Dermal Risks to Occupational Postapplication Workers Day After Exposure Daily residue dissipation percent ( minus 10% after day 0) Residue Concentration on Skinc ( ug/ cm2) Dermal MOEd Handling treated ornamental plants, Spray Formulation 0.034 lb ai/ gal, assuming 100 gallons per acre, 20% initial default transferable residue, 8 ug/ cm2 DFR on day 0.

0 ( 12 hours) 0% 7.6 1 1 ( 24 hours) 10% 6.9 1 10 ( days) 10% 2.7 2 20 10% .93 4 30 10% .32 12 40 10% .11 35 48 10% 0.049 82 49 10% 0.044 92 50 10% 0.039 100 a Maximum application rate on label ( lb ai/ gal). b Gallons of dilute applied per acre ( rangefinder). c Residue concentration available to be transferred on day A t @

= application rate in µ g/ cm2 ( lb ai/ gal * gallons/ A * conversion factors ( lb to µ g and A to cm2)* DFR available on day 0 ( 20%) * ( daily dissipation for day @

t @) * percent of DFR transferrable to skin.

d Dermal MOE = dermal endpoint 80% TGAI ( 4 µ g/ cm2) / residue concentration on skin. Page 25 of 36 2.2.4 Occupational Postapplication Exposure and Risk Estimates for Cancer Since no toxicological endpoint of concern was identified for cancer, cancer risks from occupational postapplication exposures were not assessed.

2.2.5 Summary of Occupational Postapplication Risk Concerns and Data Gaps The Agency has used the most up to date information available to complete this postapplication risk assessment for DDAC. A summary of the postapplication risks are provided in Table 6. The occupational postapplication exposure and risk assessment for ornamental crop uses of DDAC indicates that risks are of concern until:

$ day 63 for all crops and all postapplication activities, assuming 400 gallons are applied per acre,

$ day 57 for all crops and all postapplication activities, assuming 200 gallons are applied per acre,

$ day 50 for all crops and all postapplication activities, assuming 100 gallons are applied per acre.

2.2.6 Recommendations for Refining Occupational Postapplication Risk Assessment To refine this occupational risk assessment, data on actual use patterns including rates, timing, and the gallons per acre that are required to apply DDAC as a plant growth regulator would better characterize DDAC risks. In addition, DDAC specific DFR data could refine exposure and risk estimates.

3.0 Residential and Other Non Occupational Exposures and Risks It has been determined there is a potential for exposure in residential settings during the application process for homeowners who use products containing DDAC. There is also a potential for exposure from entering DDAC treated areas, such as home gardens and greenhouses that could lead to exposures to adults. Risk assessments have been completed for both residential handler and postapplication scenarios.

3.1 Residential Handler Exposures and Risks The Agency uses the term Ahandlers@ to describe those individuals who are involved in the pesticide application process. The Agency believes that there are distinct tasks related to applications and that exposures can vary depending on the specifics of each task as was described above for occupational handlers Page 26 of 36 3.1.1 DDAC Dermal Handler Exposure Scenarios Scenarios are used to define risks based on the U. S. EPA Guidelines for Exposure Assessment ( U. S. EPA; Federal Register Volume 57, Number 104; May 29, 1992). Assessing exposures and risks resulting from residential uses is very similar to assessing occupational exposures and risks, with the following exceptions:

$ Residential handler exposure scenarios are considered to be short term only, due to the infrequent use patterns associated with homeowner products.

$ Homeowner handler assessments are based on the assumption that individuals experience irritation based on hand contact with DDAC.

$ Homeowner handlers are expected to complete all tasks associated with the use of a pesticide product including mixing/ loading if needed as well as the application.

$ Master Label use rates and use information specific to residential products serve as the basis for the risk calculations.

$ Area/ volumes of spray or chemical used in the risk assessment are based on The Agency= s guidance specific to residential use patterns.

Dermal risks were estimated by using the dermal unit exposure for hands from PHED for the application equipment/ method being assessed divided by the surface area of adult hands and then normalizing for the amount handled per day ( application rate in pounds active ingredient per gallon times the gallons handled per day). The residue concentration on skin ( µ g/ cm2) was then compared directly to the dermal endpoint ( NOAEL 4 µ g/ cm2 for a 80% ai formulated product). The margin of exposure for the dermal assessment is less than 100.

It has been determined that exposure to pesticide handlers is likely during the residential use of DDAC in indoor ( greenhouse) and outdoor while treating ornamentals. The anticipated use patterns and current labeling indicate several residential handler exposure scenarios based on the types of equipment and techniques that can potentially be used to make DDAC applications. The quantitative exposure/ risk assessment developed for residential handlers is based on these scenarios. [ Note: The scenario numbers correspond to the tables of risk calculations included in the residential risk calculations in Appendix B].

Mixer/ Loader/ Applicators: ( 1) Liquid Formulations: Low Pressure Handwand ( PHED data for dermal and ORETF data for inhalation) ( 2) Wettable Powder Formulations: Low Pressure Handwand ( PHED data for dermal and inhalation) ( 3) Dry Flowable Formulations: Low Pressure Handwand ( using liquid concentrate Page 27 of 36 PHED data for dermal and liquid concentrate ORETF data for inhalation) ( 4) Liquid Concentrates: Hose End Sprayer ( PHED data for dermal and ORETF data for inhalation) ( 5) Wettable Powder Formulations: Hose End Sprayer ( no data) ( 6) Dry Flowable Formulatons: Hose End Sprayer ( no data) ( 7) Ready to Use Formulations: Hose End Sprayer ( no data) ( 8) Liquid Concentrates: Watering Can ( using PHED hose end sprayer data for dermal and ORETF hose end data for inhalation)

3.1.2 Data and Assumptions for Handler Exposure Scenarios A series of assumptions and exposure factors served as the basis for completing the residential handler risk assessments. Each assumption and factor is detailed below. In addition to these factors, unit exposure values were used to calculate risk estimates. Dermal unit exposure values were taken from the Pesticide Handlers Exposure Database ( PHED). Both PHED and the individual studies are presented below. [ Note: Several of the assumptions and factors used for the assessment are similar to those used in the occupational assessment presented above. As such, only factors that are unique to the residential scenarios are presented below.]

Assumptions and Factors: The assumptions and factors used in the risk calculations include:

$ Exposure factors used to calculate daily exposures to handlers were based on applicable data if available. When appropriate data is unavailable, values from a scenario deemed similar might be used.

$ HED typically considers the maximum application rates allowed by labels in its risk assessments. If additional information such as average or typical rates is available, these values also may be used to allow risk managers to make a more informed risk management decision. Average/ typical application rates were not available for residential scenarios.

$ Residential risk assessments are based on estimates of what homeowners would typically treat, such as the size of a lawn or the size of a garden. The factors used for the DDAC assessment were from the Health Effects Division Science Advisory Committee Policy 12: Recommended Revisions to the Standard Operating Procedures for Residential Exposure Assessment which was completed on February 22, 2001, and on professional judgement. The daily volumes handled used in each residential scenario are provided in Table 4.

Residential Handler Exposure Studies: The unit exposure values that were used in this assessment were based on the Outdoor Residential Exposure Task Force studies and the Pesticide Handler Exposure Database ( PHED, Version 1.1 August 1998) [ Note: PHED and some ORETF studies are described above in Section 2.1.1.] More details can be found in Appendix A.

3.1.3 Residential Handler Exposure and Risk Estimates Page 28 of 36 Risks were calculated using the Margin of Exposure ( MOE) as described in Section 2.1.3. Assessing exposures and risks resulting from residential uses is very similar to assessing occupational exposures and risks, except as described in Section 3.1.1.

Residential Risk Summary The Agency believes that the scenarios assessed in this document represent worse case exposures and risks resulting from use of DDAC in residential environments. It should be noted that there were many other scenarios where medium to low PHED quality data were used to complete the assessment. Data quality should be considered in the interpretation of the uncertainties associated with each risk value presented.

Short term dermal and inhalation risks for residential handlers ( intermediate term exposures are not likely because of the intermittent nature of applications by homeowners) are presented in Tables 7, 8, and 9. When the end use product is formulated with 10% or less of DDAC, one scenario for residential handlers is of concern. Mixing/ loading/ applying liquid concentrates with a hose end sprayer is of concern for ornamental plants at the 0.034 lb ai/ gal rate with an MOE of 68. When the end use product is formulated with more than 10% DDAC, the dermal risks for residential handlers are of concern for all DDAC residential handler scenarios where data are available. The short term inhalation risks for residential handlers are not of concern for any residential uses of DDAC.

Table 7: Short term Dermal Risks to Residential Handlers Using Formulations with 10% or Less DDAC Scenario Crop/ Target Application Ratea ( lb ai/ gal) Quantity Handled per Dayb ( gallons/ day) Unit Exposure for Handsc ( mg/ lb ai) Surface Area of Adult Handsd ( cm2) Estimated Residue Transferred to Skin of Handse ( ug/ cm2/ day) Dermal MOEf ( UF = 100)

Mixing/ Loading Applying ( M/ L/ A) Liquid Concentrates with Low Pressure ( LP) Handwand ( 1) 0.034 5 102 820 21 370 M/ L/ A Wettable Powders ( WP) with LP Handwand ( 2) Ornamental Plants ( drench or spray)

0.034 5 229 820 47 160 Page 29 of 36 Table 7: Short term Dermal Risks to Residential Handlers Using Formulations with 10% or Less DDAC Scenario Crop/ Target Application Ratea ( lb ai/ gal) Quantity Handled per Dayb ( gallons/ day) Unit Exposure for Handsc ( mg/ lb ai) Surface Area of Adult Handsd ( cm2) Estimated Residue Transferred to Skin of Handse ( ug/ cm2/ day) Dermal MOEf ( UF = 100)

M/ L/ A Dry Flowables ( DF) with LP Handwand ( 3) 0.034 5 102 820 21 370 M/ L/ A Liquid s with Hose end Sprayer ( 4) 0.034 100 27.5 820 110 68 M/ L/ A Liquids with a Watering Can ( PHED residential hose end data as surrogate) ( 8) 0.034 5 27.5 820 6 1,400 a Application rates are the maximum application rates determined from EPA registered labels for DDAC b Amount handled per day values are HED estimates of acres, square feet, or cubic feet treated or gallons applied based on Exposure SAC SOP # 9 A Standard Values for Daily Acres Treated in Agriculture,@ industry sources, and HED estimates. c From residential PHED unit exposures values for hands for the scenarios listed. d From Exposure Factors Handbook e Application rate ( lb ai/ gal) * amount handled per day ( gal/ day) * dermal unit exposures value ( mg/ lb ai) * conversion factor mg to µ g ( 1000) / surface area of adult hands ( cm2) f Dermal MOE = Estimated Residue transferred to Skin of Hands ( µ g/ cm2/ day)/ Dermal Endpoint ( 7750 µ g/ cm2/ day) for 6% ai product Table 8: Short term Dermal Risks to Residential Handlers Using Formulations with More than 10% DDAC Page 30 of 36 Scenario Crop/ Target Application Ratea ( lb ai/ gal) Quantity Handled per Dayb ( gallons/ day) Unit Exposure for Handsc ( mg/ lb ai) Surface Area of Adult Handsd ( cm2) Estimated Residue Transferred to Skin of Handse ( ug/ cm2/ day) Dermal MOEf ( UF = 100)

M/ L/ A Liquid LP Handwand ( ORETF data) ( 1) 0.034 5 102 820 21 < 1 M/ L/ A WP with LP Handwand ( 2) 0.034 5 229 820 47 < 1 M/ L/ A Water Dispersible Granules ( WDG) with LP Handwand ( liquid concentrate ORETF data as surrogate) ( 3) 0.034 5 102 820 21 < 1 M/ L/ A Liquid Concentrates with a Hose end Sprayer ( 4) Ornamental Plants ( drench or spray)

0.034 100 27.5 820 110 < 1 M/ L/ A Liquids with a Watering Can ( ORETF residential hose end data as surrogate) ( 8) Ornamental Plants ( drench) 0.034 5 27.5 820 6 < 1 a Application rates are the maximum application rates determined from EPA registered labels for DDAC b Amount handled per day values are HED estimates of acres, square feet, or cubic feet treated or gallons applied based on Exposure SAC SOP # 9 A Standard Values for Daily Acres Treated in Agriculture,@ industry sources, and HED estimates. c From residential PHED unit exposures values for hands for the scenarios listed. d From Exposure Factors Handbook e Application rate ( lb ai/ gal) * amount handled per day ( gal/ day) * dermal unit exposures value ( mg/ lb ai) * conversion factor mg to µ g ( 1000) / surface area of adult hands ( cm2) f Dermal MOE = Estimated Residue transferred to Skin of Hands ( µ g/ cm2/ day)/ Dermal Endpoint ( 4.0 µ g/ cm2/ day) for 80% TGAI Page 31 of 36 Table 9: Short term Inhalation Risks to Residential Handlers Scenario Crop/ Target Application Ratea ( lb ai/ gal) Quantity Handled/ Treated per Dayb ( gal/ day) Baseline Inhalation Unit Exposurec ( ug/ lb ai) Baseline Inhalation Exposured ( mg/ day) Baseline Inhalation Dosee ( mg/ kg/ day) Inhalation MOEf UF = 100)

M/ L/ A Liquid Concentrates with LP Handwand ( 1) 0.034 5 2.7 0.00046 7.7E 06 7,800,000 M/ L/ A WP with LP Handwand ( 2) 0.034 5 1063 0.18 0.003 20,000 M/ L/ A WDG LP Handwand ( liquid concentrate ORETF data as surrogate) ( 3) 0.034 5 2.7 0.00046 7.7E 06 7,800,000 M/ L/ A Liquid Concentrates with a Hose end Sprayer ( 4) 0.034 100 0.82 0.0028 0.000046 1,300,000 Loading/ Applying Readyto Use Formulation with a Hose end Sprayer ( 7) Ornamental Plants ( drench or spray)

0.034 100 11 0.037 0.00062 97,000 M/ L/ A Liquids with a Watering Can ( ORETF residential hose end data as surrogate) ( 8) Ornamental Plants ( drench) 0.034 5 17 0.0029 0.000048 1,300,000 a Application rates are the maximum application rates determined from EPA registered labels for DDAC b Amount handled per day values are HED estimates of gallons applied per day based on Exposure SAC SOP # 9 A Standard Values for Daily Acres Treated in Agriculture,@ industry sources, and HED estimates. c Baseline Inhalation: no respirator. d Baseline inhalation exposure ( mg/ day) = application rate ( lb ai/ gal ) x amount handled per day ( gal/ day) x baseline inhalation unit exposure ( µ g/ lb ai) x conversion factor from µ g to mg ( 0.001) e Baseline inhalation dose ( mg/ kg/ day) = baseline inhalation exposure ( mg/ day) x inhalation absorption factor ( 100%) / female bodyweight ( kg) f Inhalation MOE = inhalation NOAEL ( 10 mg/ kg/ day) / baseline inhalation dose ( mg/ kg/ day)

3.1.4 Residential Handler Exposure and Risk Estimates for Cancer Page 32 of 36 Residential handler cancer risks are not assessed, since no toxicological endpoint of concern for cancer was selected.

3.1.5 Summary of Risk Concerns and Data Gaps for Handlers Risks for all inhalation scenarios were not of concern for residential handlers. When the end use product is formulated with 10% or less of DDAC, one scenario for residential handlers is of concern. Mixing/ loading/ applying liquid concentrates with a hose end sprayer is of concern for ornamental plants at the 0.034 lb ai/ gal rate with an MOE of 68. However all residential dermal scenarios were of concern when the end use product formulation was more than 10 percent.

There are several data gaps identified by HED for residential handlers including:

$ mixing/ loading/ applying dry flowables with low pressure handwand sprayers and with hose end sprayers;

$ mixing/ loading/ applying wettable powders with hose end sprayers;

$ mixing/ loading/ applying liquid concentrates with a sprinkling can.

3.1.6 Recommendations for Refining Residential Handler Risk Assessment In order to refine this residential risk assessment, more data on actual use patterns including rates, timing, and areas treated would better characterize DDAC risks. In addition, if ORETF hand data are available separately from other dermal data, then ORETF hand data could be used to refine the dermal exposures and risks. Exposure studies for many equipment types that lack data or that are not well represented in PHED ( e. g., because of low replicate numbers or data quality) should also be considered based on the data gaps identified above and based on a review of the quality of the data used in this assessment.

3.2 Residential Postapplication Exposures and Risks HED uses the term Apostapplication@ to describe exposures to individuals that occur as a result of being in an environment that has been previously treated with a pesticide. DDAC can be used in many areas that can be frequented by the general population including residential areas ( e. g., home greenhouses and gardens). As a result, individuals can be exposed by entering these areas if they have been previously treated.

3.2.1 Residential Postapplication Exposure Scenarios Postapplication exposure scenarios were developed for each residential setting where DDAC can be used. Assessing postapplication exposures and risks resulting from residential uses is very similar to assessing occupational postapplication exposures and risks ( Section 2.2), except in residential assessments the risks must not be of concern on day 0. Page 33 of 36 HED relies on a standardized approach for completing residential risk assessments that is based on current DDAC labels and guidance contained in the following five documents:

$ Series 875, Residential and Residential Exposure Test Guidelines: Group B  Postapplication Exposure Monitoring Test Guidelines ( V 5.4, Feb. 1998): This document provides general risk assessment guidance and criteria for analysis of residue dissipation data.

$ Standard Operating Procedures for Residential Exposure Assessment ( Dec. 1997): This document provides the overarching guidance for developing residential risk assessments including scenario development, algorithms, and values for inputs.

$ Science Advisory Council for Exposure Policy 12 ( Feb. 2001): Recommended Revisions To The Standard Operating Procedures ( SOPs) For Residential Exposure Assessment: This document provides additional, revised guidance for completing residential exposure assessments.

$ Overview of Issues Related to the Standard Operating Procedures for Residential Exposure Assessment ( August 1999 Presentation To The FIFRA SAP): This document provides rationale for Agency changes in SOPs.

Usually HED considers children of differing ages as well as adults in its postapplication residential exposure and risk assessments. Only adults were considered in the assessment since the dermal endpoint is for skin irritation potential. The sole postapplication residential scenario assessed is for residential adults. These individuals are members of the general population that are exposed to chemicals by engaging in activities at their residences ( e. g., in home greenhouses or gardens) previously treated with a pesticide. These kinds of exposures are attributable to a variety of activities and are usually addressed by HED in risk assessments by considering a representative activity as the basis for the exposure calculation.

The SOPs for Residential Exposure Assessment define several scenarios that apply to uses specified in current labels. These scenarios served as the basis for the residential postapplication assessment along with the modifications to them and the additional data and approaches described above. HED used this guidance to define the exposure scenarios that essentially include dermal exposure to adults in treated greenhouses and gardens. The SOPs and the associated scenarios are presented below:

$ Potential residues on skin from dermal exposure to treated foliage in greenhouses or gardens.

3.2.2 Data and Assumptions for Residential Postapplication Exposure Scenarios Page 34 of 36 Assumptions and Exposure Factors A series of assumptions and exposure factors served as the basis for completing the residential postapplication risk assessments. The assumptions and factors used in the risk calculations are consistent with current Agency policy for completing residential exposure assessments ( i. e., SOPs for Residential Exposure Assessment). The values used in this assessment include:

$ There are many factors that are common to the occupational and residential postapplication risk assessments, such as body weights for adults and analysis of residue dissipation data, Please refer to the assumptions and factors in Section 2.1.2 for further information concerning these common values.

$ Exposures to adults working in home greenhouses and gardens have been addressed using the latest HED approaches for this scenario including: the DFR data used for the assessments are the default assumption that 20 percent of the application rate is available for transfer, since no DDAC specific DFR data are available.

$ Postapplication residential risks are based on maximum application rates or values specified in the SOPs for Residential Exposure Assessment.

3.2.3 Residential Postapplication Exposure and Risk Estimates Risks were calculated using the Margin of Exposure ( MOE) approach, which is a ratio of the skin burden to the dermal endpoint of concern. Exposures were calculated by considering the potential sources of exposure ( i. e., DFRs on ornamental plants), then calculating potential skin residues.

Dermal Exposure from Treated Ornamental Greenhouses and Gardens ( adult)

The approach used to calculate the dermal exposures that are attributable to exposure from contacting treated gardens is:

RC( 0) = AR ( lb ai/ A) x CF1 x CF2 x F Where:

RC( 0) = Residue concentration transferred to the surface of the skin on day ( t) attributable for activity in a previously treated area ( µ g/ cm2/ day); AR = application rate in lb ai/ A ( if application rate is lb ai/ gal, then this is multiplied by the gallons of dilute applied per acre to achieve lb ai/ A); CF1 = Conversion factor from pounds to micrograms ( 4.5E+ 08); CF2 = Conversion factor from acres to centimeters squared ( 2.47E 08); Page 35 of 36 F = fraction of ai available for transfer on day 0 ( 20%)

Residential Risk Summary:

Adults Table 10 presents the postapplication MOE values calculated for adults after home greenhouse or garden applications of DDAC. The short term dermal MOEs are less than 100 on the day of application for these scenarios and are of concern.

Table 10: Dermal Risks to Residential Postapplication Workers Exposure Scenario Formulation Application Ratea ( lb ai/ gal) Gallons per Acresb Day After Exposure Default transferable residue (%) Default DFR on Postapplication Day Zeroc ( ug/ cm2) Residue Concentration on Skin ( ug/ cm2) Dermal MOEd Assuming 400 gallons per acre Handling Treated Ornamental Plants Spray 0.034 400 0 ( 12 hours) 20% 31 31 < 1 Assuming 200 gallons per acre Handling Treated Ornamental Plants Spray 0.034 200 0 ( 12 hours) 20% 15 15 < 1 Assuming 100 gallons per acre Handling Treated Ornamental Plants Spray 0.034 100 0 ( 12 hours) 20% 7.6 7.6 < 1 a Maximum application rate on label ( lb ai/ gal). b Gallons of dilute applied per acre ( rangefinder). c Residue concentration available to be transferred on day A t @

= application rate in µ g/ cm2 ( lb ai/ gal * gallons/ A * conversion factors ( lb to µ g and A to cm2)* DFR available on day 0 ( 20%) * ( daily dissipation for day @

t @) * percent of DFR transferrable to skin d Dermal MOE = dermal endpoint 80% TGAI ( 4 ug/ cm2)/ residue concentration on skin 3.2.4 Residential Postapplication Exposure and Risk Estimates for Cancer Residential postapplication cancer risks were not assessed for DDAC, since no toxicological endpoint of concern was selected for cancer. Page 36 of 36 3.2.5 Summary of Residential Postapplication Risk Concerns and Data Gaps Short term MOEs were calculated for adults performing tasks in home greenhouses and gardens following applications of DDAC. Cancer risks were not calculated, since no toxicological endpoint for cancer was selected. In residential settings, HED does not use restricted entry intervals or other mitigation approaches to limit postapplication exposures, because they are viewed as impractical and not enforceable. As such, risk estimates on the day of application are the key concern.

In the assessment for residential postapplication exposure and risk, there are risk concerns for DDAC as it is currently used in a residential environment.

3.2.6 Recommendations for Refining Residential Postapplication Risk Assessments In order to refine this residential assessment, data on actual use patterns including rates, timing, and the kinds of tasks performed are required to better characterize DDAC risks.