### REVISED DRAFT Tributlytin - containing Compounds Tributyltin oxide (TBTO) Tributyltin benzoate (TBTB) Tributyltin maleate (TBTM) Occupational and Residential Exposure Assessment

Office of Pesticide Programs Antimicrobials Division U.S. Environ mental Protection Agency

One Potomac Yard 2777 South Crystal Drive Arlington, VA 22202
- 4501

Date: June 26 , 2008Page 1 of 43



### TABLE OF CONTENTS EXECUTIVE SUMMARY ................................ ................................ ................................ ................................ .... 2 1.0 INTRODUCTION ................................ ................................ ................................ ................................ ... 5 1.1 Purpose ................................ ................................ ................................ ................................ ................ 5 1.2 Criteria for Conducting Exposure Assessments ................................ ................................ ................... 5 1.3 Chemical Identification ................................ ................................ ................................ ........................ 7 1.4 Physical/Chemical Properties ................................ ................................ ................................ .............. 7 2.0 USE IN FORMATION ................................ ................................ ................................ ............................ 8 2.1 Formulation Types and Percent Active Ingredient ................................ ................................ ............. 8 2.2 Summary of Use Pattern and Formulations ................................ ................................ ........................ 8 3.0 SUMMARY OF TOXICITY DATA ................................ ................................ ................................ ....... 9 3.1 Acute Toxicity ................................ ................................ ................................ ................................ ..... 9 3.2 Summary of Toxicity Endpoints ................................ ................................ ................................ ........ 10 4.0 RESIDENTIAL EXPOSURE ASSESSMENT ................................ ................................ ...................... 13 4.1 Summary of Registered Uses ................................ ................................ ................................ ............. 13 4.2 Residential Exposure ................................ ................................ ................................ ......................... 13 4.2.1 Residential Handler Exposures ................................ ................................ ................................ 14 4.2.2 Residential Post
- application Exposures ................................ ................................ ................... 16 4.2.2.1 Textiles ........ ........................................................................................ ... ... 16 4.2.2.2 Mattresses................................................................................................... 19 4.2.3 Data Limitations/Uncertainties.......................................................................... 22 5.0 RESIDENTIAL AGGREGATE RISK ASSESSMENT AND CHARACTERIZATION ..................... 24 6.0 OCCUPATIONAL EXPOSURE ASSESSMENT ................................ ................................ ................. 24 6.1 Occupationa l Handler Exposures ................................ ................................ ................................ ....... 26 6.2 Occupational Post
- application Exposures ................................ ................................ .......................... 31 6.4 Data Limitations/Uncertainties ................................ ................................ ................................ .......... 35 7.0 REFERENCES ................................ ................................ ................................ ................................ ....... 36 APPENDIX A: Summary of CMA and PHED Data ................................ ................................ ............................ 37 APPENDIX B: MCCEM O utput (Fogging) .................. ........................... ..................................... 37Page 2 of 43



### EXECUTIVE SUMMARY This document is the Occupational and Residential Exposure Chapter of the Reregistration Eligibility Decision (RED) document for the tributly tin (TBT)
- c ontaining compounds including tributyltin oxide (TBTO), tributyltin benzoate (TBTB), and tributyltin maleate (TBTM) . It addresses the potential risks to humans that result from its direct use in occupational settings and resulting treated articles in residential settings. TBT is used as a bacteriostat, microbicide/microbistat, fungicide, slimicide, algaecide, antifoulant, virucide, disinfectant, sanitizer, miticide, and insecticide . TBT is formulated as a soluble concentrate. T BT concentration s in produ cts range from 0.3 to 53 perc ent (i.e., 74489
- 1) . The product is used in the following use categories: agricultural premises, commercial/ institutional/industrial premises and equipment, material preservatives, industrial processes and water systems , anti fouling coatings, and wood preservations (i.e., stains/water sealants) . Examples of uses for TBT in these settings include its use by residential and commercial painters ( as a wood preservative), as a material preservative incorporated into textiles, metalworking fluids, oil field injection systems , l aundry additive , sonar domes, and in industrial process water systems such as pulp and paper mills, cooling tower water (recirculating cooling towers), etc. The durations and routes of exposure evaluated in this assessment include short
- term (ST), intermediate
- term (IT), and/or long
- term (LT) durations for the inhalation, dermal, and oral routes of exposure. The oral, dermal, and inhalation endpoint s for all durations (ST/IT/LT durations) are based on the s ame study . The BMD 10 

### (bench mark dose) of 0.03 mg/kg/day (NOAEL of 0.025 mg/kg/day and LOAEL of 0.25 mg/kg/day ) is used for all durations. The adverse effect for this endpoint is based on immunosupression. Because the toxicological endpoints selected fo r inhalation, dermal, and oral routes of exposure are not female
- specific, a body weight of 70 kilograms is used in the assessment. EPA’s level of concern (LOC) for occupational and residential TBT inhalation, dermal, and oral routes of exposures is 100 ( i.e., a margin of exposure (MOE) less than 100 exceeds the level of concern). The level of concern is based on 10x for interspecies extrapolation and 10x for intraspecies variation. An additional 10 x special sensitivity factor is applied to the non occupational population. This occupational and residential assessment was based on examination of the product label s that describe the uses. It has been determined that there are residential products of TBT that are applied directly (e.g., wood stain pre servative) as well as an in
- can preservative use (e.g., laundry additive 10466
- 24) . Occupational handlers may be exposed in the manufacturing of other products (e.g., textiles ), during treatment of water systems, agricultural poultry, farm premise applications, commercial painters, and metalworking fluids (MWF). Post
- application exposures are likely to occur in residential settings by contacting treated articles such as clothing or in occupational settings such as reentry into poultry /animal premises . The representative scenarios selected by EPA for assessment were evaluated using maximum application rates as stated on the product label s . The representative scenarios are believed to represent high
- end uses resulting in dermal, inhalation, and incidental o ral exposures.Page 3 of 43



### To assess the handler risks, EPA used surrogate unit exposure data from the Chemical Manufacturers Association (CMA) antimicrobial exposure study and the Pesticide Handlers Exposure Database (PHED). Post application/bystander exposures were assessed using EPA’s standard assumptions (e.g., Health Effects Division’s (HED) Standard Operating Procedures (SOPs) for Residential Exposure Assessment). Residential Handler Risk Summary Dermal The residential handler dermal exposure scenarios are best represented by the short
- term duration (i.e., staining with a paint brush and /or airless sprayer are considered to be intermittent in nature). The short
- term dermal MOEs for the paint brush and airless sprayer are both < 1 , and therefore, the risks are of concern . The residential target MOE is 1000. Inhalation For the residential painting inhalation assessment, the inhalation MOEs were less than 1 which is below the target MOE of 1 0 00 for the brush and airless application techniques , and therefore, are of concern. Residential Post Application/Bystander Risk Summary Dermal & Oral The residential post
- application short
- and intermediate
- term dermal and incidental oral risks were assessed for children and/or adults coming in contact with or wearing treated textiles such as clothing. Dermal risks are of concern using the transfer residue study developed for a screening
- level assessment (i.e., toddler dermal MOE = 35 ). A second residue transfer study was conducted to refine the transfer of residues . This study determined the residues to be <10 ppb. However, there is insufficient information available in the study to assume that a reasonable certainty of no harm would occur from a child exposed to TBTO
- treated fabric using the revised methodology . In addition, the incidental oral exposures from children mouthing treated fabric is of concern (oral MOE = 2 ). Furthermore, the dermal MOEs are also of concern for dermal contact on TBT - treated mattresses (MOE i s 8 for children when using the transfer re sidue data from the first residue transfer study ). Inhalation Based on the application methods, inhalation exposure is expected to be minimal. Occupational Handler Risk Summary In summary, fo r the non fogging agricultural uses the inhalation MOEs are greater than 100, and therefore not of concern. Some of the dermal MOEs for the same scenarios are above and some below the target MOE of 100. However, the use of chemical resistant gloves was not assessed for all scenarios because the data were not available. Based on the low application rate (i.e., 0.00033 lb ai/gallon), the magnitude of the MOEs, and assuming that chemical resistantPage 4 of 43



### gloves would afford substantial reduction in exposure, these dermal MOEs do not appear to be of concern if gloves are required on the labels (confirmatory data would be required). The MOEs for the material preservative use are below the target MOE of 100. Potential mitigation for material preservative additives would be to require closed loading systems. The industrial process and water system uses also need to be restricted to closed loading systems. At this time, it is unclear how the antifouling coatings are applied and additional information on the application techniques are requested. Finally, the commercial app lication s of stains indicate MOEs of concern (i.e., MOEs less than 1). Occupational Post Application/Bystander Risk Summary Based on the application methods, inhalation post
- application exposure s are expected to be minimal except for the machinist using TBT - treated cutting fluids . The dermal and inhalation MOEs for machinists are 3 and 36, respectively . The risks are of concern for the machinist. Data Limitations and Uncertainties: There are a number of uncertainties associated with this assessment and these have been reiterated from Sections 4.2.3 (residential) and 6.4 (occupational). The data limitations and uncertainties associated with the handler and post
- application exposure assessments include the following:

· Surrogate dermal and inhalation unit exposure values were taken from the proprietary Chemical Manufacturers Association (CMA) antimicrobial exposure study (USEPA, 1999: DP Barcode D247642) or from the Pesticide Handler Exposure Database (USEPA, 1998) (See Appendix B for summaries of these data sources). Most of the CMA data are of poor quality therefore, EPA requests that confirmatory monitoring data be generated to support the values used in these assessments. · The quantities handled/treated were estimated based on information from various sources, including HED’s Standard Operating Procedures (SOPs) for Residential Exposure Assessments (USEPA 2000, and 2001). In certain cases, no standard values were available for some scenarios. Assumptions for these scenarios were based on EPA estimates and could be further refined from input from registrants.Page 5 of 43



### 1.0 INTRODUCTION 1.1 Purpose In this document, EPA’s Antimicrobials Division (AD) presents the results of its review of the potential human health effects of occupational and residential exposure to TBT - containing compounds (TBTO, TBTB, TBTM) , case number 26 20 . The information presented in this Occupational and Residential Exposure chapter is for use in EPA's development of the TBT Reregistration Eligibility Decision (RED) document. 1.2 Criteria for Conducting Exposure Assessments An occupational and/or residential exposure assessment is required for an active ingredient i f (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 T B T , both criteria are met. Toxicolo gical endpoints were selected for short
- , intermediate
- , and long
- term dermal, inhalation, and incidental oral exposures to T B T . There is the potential for exposure in a variety of occupational and residential settings. Therefore, risk assessments are req uired for occupational and residential handlers as well as for occupational and residential post application exposures that can occur as a result of T B T use. In this document, handler scenarios were assessed by using unit exposure data to estimate occupational and residential handlers’ exposures. Unit exposures are estimates of the amount of exposure to an active ingredient a handler receives while performing various handler tasks and are expressed in terms of micrograms or milligrams (1 mg = 1,000 μg) of active ingredient per pounds of active ingredient handled. A series of unit exposures have been developed that are unique for each scenario ty pically considered in assessments (i.e., there are different unit exposures for different ty pes of application eq

uipment, job functions, and levels of protection). The unit exposure concept has been established in the scientific literature and also through various exposure monitoring guidelines published by the USEPA and international organizations such as Health Canada and OECD (Organization for Economic Cooperation and Development). Using surrogate unit exposure data, maximum application rates from labels, and EPA estimates of daily amount handled, exposures and risks to handlers were assessed. The exposure/ris ks were calculated using the following equations: Daily Exposure: Daily inhalation and dermal handler exposures are estimated for each applicable handler task with the application rate, quantity treated/handled in a day, and the applicable inhalation unit exposure using the following formula: Daily Exposure: E = UE x AR x AT (Eq. 1) Where: E = Amount (mg ai/day) inhaled or contacted dermally that is available for absorption;Page 6 of 43

UE = Unit exposure value (mg ai/lb ai) derived from August 1998 PHED data or from 1992 CMA data; AR = Maximum application rate based on a logical unit treatment, such as square feet (sq. ft.), gallons

(gal), or cubic feet (cu. ft). Maximum values are generally used (lb ai/sq ft, lb ai/gal, lb ai/cu ft); and AT = Normalized appl ication area based on a logical unit treatment such as square feet (sq ft/day),

gallons (gal/day), or cubic feet (cu ft/day). 

### Daily Dose: The inhalation and dermal doses are calculated by normalizing the daily exposure by body weight and adjusting, if n ecessary, with an appropriate absorption factor. An absorption factor of 100% was used for inhalation exposures. An absorption factor was not necessary for dermal exposures because a route
- specific dermal endpoint is available. Daily dose was calculated using the following formula: Daily Dose: ADD = E x ABS (Eq. 2)

BW Where: ADD = Average daily dose or the absorbed dose received from exposure to a chemical in a given scenario (mg active ingredient/kg body weight/day); E = Amount (mg ai/day) inhaled or contacted dermally that is available for absorption; ABS = A measure of the amount of chemical that crosses a biological boundary such as lungs (% of the total available absorbed); and BW = Body we ight determined to represent th e population of interest in a risk assessment (kg). 

### Margins of Exposure: Non - cancer inhalation and dermal risks for each applicable handler scenario are calculated using a Margin of Exposure (MOE). This is the ratio of the daily inhalation or dermal dos e to the toxicological endpoint of concern. Margins of Exposure: MOE = NOAEL or LOAEL (Eq. 3) ADD Where: MOE = Margin of exposure, value used to represent risk or how close a chemical exposure is to being a concern (unitless); NOAEL or L OAEL = Systemic toxicity level where no observed adverse effects (NOAEL) or where the lowest observed adverse effects (LOAEL) occurred in the study (mg ai/kg body weight/day); and ADD = Average daily dose in a given scenario (mg ai/kg body weight/day) . 

### In addition to the target MOEs presented in Table 3.2 that were used for the analysis, a series of assumptions and exposure factors served as the basis for completing the handler risk assessment. Each general assumption and factor for both residential and occupational assessments is detailed below. Assumptions specific to the use site category are listed in each separate section of this document. The general assumptions and factors include:Page 7 of 43



### · The T B T product s have a large number of use patterns that are difficult to completely capture in this document. As such, EPA has patterned this risk assessment on a series of likely representative scenarios for each use site that are believed by EPA to represent the vast majority of T B T uses. · Based on the adverse effects for the endpoints, the body weight of 70 kg is used for the inhalation and dermal and oral routes of exposure. · Exposure factors used to calculate daily exposures to handlers were based on applicable data, if available. When appropriate data were lacking, values from a scenario deemed similar were used. · The maximum application rates allowed by labels were assumed. 1.3 Chemical Identification Molecular structures for tributly tin
- containing compounds are illustrated in Figure 1 .
HO O

O

O S n C

H3 C H3 H3 C 

### Figure 1. Molecular Structure s of TBT O, TBTB, and TBTM, respectively . 1.4 Physical/Chemical Properties Table 1.2 shows physical/chemical characteristics that have been reported for TBT (TBT Product Chemistry Chapter) .

Table 1.2. Physical/Chemical Properties of TBT Parameter TBTO TBTB 

### TBTM Molecular Weight (g/mol) 596 411 4 05.13 Half life in air 0.125 days 0.241 days 2.5 hrs Boiling Point ( 

###  ̊C) 417 390 41 5 Water Solubility (mg/L) 0.0896 0.257 4.086 Vapor Pressure (

### mm Hg at 25  ̊C) 7.8E - 6 1.34E - 6 1 . 74 E - 7Page 8 of 43



### 2.0 USE INFORMATION 2.1 Formulation Types and Percent Active Ingredient TBT is used as a bacteriostat, microbicide/microbistat, fungicide, slimicide, algaecide, antifoulant, virucide, disinfectant, sanitizer, miticide, and insecticide. TBT is formulated as a soluble concentrate. TBT concentrations in products range from 0.3 to 53 percent (i.e., 74489
- 1). 2.2 Summary of Use Pattern and Formulations The Agency determines potential exposures to handlers of pesticide products by identifying exposure scenarios from the various application methods that are plausible, given the labeled uses. The following Use Site Categories (USC) w as identified based on a review of the T B T product label s :

n (I) Agricultural premises and equipment; n (III) Commercial, institutional and i ndustrial premises and equipment ; n (VII) Material preservatives; n (VIII) Industri al processes and water systems; n ( IX ) Antifoul ing coatings; and n (X ) Wood p reservatives. Specific uses within these use categories are identified in Tabl e 2.1. From Table 2.1, EPA has selected representative exposure scenarios to assess TBT in this document. These scenarios were selected to be representative of the vast majority of uses and are believed to provide high
- end degrees of dermal, inhalation, or incidental ingestion exposure. The representative scenarios assessed in this document are shown in Table 4.1 (residential) and Table 6.1 (occupational). Table 2.1. Potential Use Scenario s Based on Product Labels for TBT. Use Site Category Example Us e Sites Scenarios Use Site Category I Agricultural premises and equipment · Use Site Category III Commercial, institutional and industrial premises and equipment · Polymers Use Site Category VII Material Preservatives Used in the production of various household, institutional and industrial items Addition to products during manufacture, including: · Polymers Use Site Category VIII Industrial processes and water systems Used on fresh water supplies for commercial and industrial systems · Addition to water for recirculating cooling towers · Use Site CategoryPage 9 of 43

Antifoulant coatings Use Site Category Wood preservatives Used in preservation of wood products 

### 3.0 SUMMARY OF TOXICITY DATA 3.1 Acute Toxicity The acute toxicity data for T B T are summarized below in Table 3.1. The acute toxicity database for the tributyltin compounds is considered incomplete; the battery of acute toxicity studies required for labeling purposes has not been submitted by the registrants for each of the tributyltin compounds (tributyltin oxide, tributyltin maleate and tributyltin benzoate) grouped in this hazard assessment. The available data does show that exposure to tributy ltin oxide and tributyltin maleate can result in severe oral and dermal toxicities (Toxicity Category II). However, tributyltin oxide and tributyltin maleate are not dermal sensitizers. Dermal and oral exposures to tributyltin benzoate can potentially cause moderate (Toxicity category III) t o severe (Toxicity category II) toxicities, respectively . Table 3.1. Acute Toxicity Profile for Technical (95.0 - 97.5 % a.i.) Tributyltin Compounds Guideline Number Study Type MRID Number Results Toxicity Category Tributyltin O xide 870.1100 (§ 81
- 1) Acute Oral

– Rat 00085004, 92172013 LD 50 =180 mg/kg (males)

LD 50 =150 mg/kg (females) LD 50 =170 mg/kg (combined) II

870.1100 (§ 81
- 1) Acute Oral

– Rat 00085003, 92172004 LD 50 =193 mg/kg (males)

LD 50 =123 mg/kg (females) LD 50 =1 60 mg/kg (combined) II

870.2600 (§ 81
- 6) Skin Sensitization

–

Guinea pigs 00104789, 92172014 Non sensitizer Not applicable 

### T ributyltin Maleate 870.1100 (§ 81
- 1) Acute Oral

– Rat 43851201 LD 50 = 224.7 mg/kg II 870.2600 (§ 81
- 6) Skin Sensitization

–

Guinea pigs 44142303 Non sensitizer. Not sensitizing; minimal irritation in response to induction, but no increase in response to challenge dose Not applicablePage 10 of 43 

### Tributyltin B enzoate 870.1100 (§ 81
- 1) Acute Oral

– rat

Purity 42415801 LD 50 =115 mg/kg (mal es) LD 50 =115 mg/kg (females) LD 50 =115 mg/kg (combined) II

870.1200 (§ 81
- 2) Acute Dermal

– rat

Purity 42415802 LD 50 > 2000 mg/kg (combined) III 870.2500 (§ 81
- 5) Primary Dermal

Irritation

– rabbit Purity 42415803 Severe Irritation I



### 3.2 Summa ry of Toxicity Endpoints Table 3.2 summarizes the toxicological endpoints for T B T. Exposure Scenario Dose Used in Risk

Assessment (mg/kg/day) Special Sensitivity*,

UF , Target MOE, for Risk Assessment Study and Toxicological Effects Dietary Risk Assessments Acute Dietary (females 13
- 49 and general population) No appropriate endpoints were identified in the oral toxicity studies that represent a single

dose effect for the general population and females 13
- 49. In addition, the current use patterns for the tributyltin
- containing chemicals do not indicate the potential for direct or indirect dietary exposures. Therefore, an acute dietary risk assessment is not required.Page 11 of 43



### Exposure Scenario Dose Used in Risk

Assessment (mg/kg/day) Special Sensitivity*,

UF , Target MOE, for Risk Assessment Study and Toxicological Effects Chronic Dietary (all populations) BMD 10 = 0.03

mg/kg/day based on immunosupression (established by EPA/IRIS and used to estimate their oral RfD of 0.0003 mg/kg/day

). Special Sensitivity = 10 UF = 100 (10x inter
species extrapolation, 10x intra
- specie s variation) Chronic RfD (cRfD) = 0.00003 mg/kg/day Although the current use patterns for the tributyltin
containing chemicals do not indicate the potential for chronic dietary exposures, this endpoint is selected for future reference. A chronic dietary risk assessment is not required at this time. Open Literature Study Vos et al. , (1990) Immunotoxicity of bis(tri
- n -butyltin)oxide in the rat: Effects on thy

mus - dependent immunity and on nonspecific resistance following long
- term exposure in young vs aged rats. Toxicol. Appl. Pharmacol. 105:144
- 155. NOAEL = 0.025 mg/kg/day LOAEL = 0.25 mg/kg/day based on immunotoxicity (depression of IgE titers and increase in T. spiralis larvae in muscle) following 4 months and 16.5 months of exposure to Tributyl T in Oxide. (Review by EPA/IRIS, 1997). Non - Dietary Risk Assessments Incidental Oral Short
- Term (1
- 30 days) and Intermediate
- Term (1
- 6 months) BMD 10 = 0.03

mg/kg/day based on immunosupression (established by EPA/IRIS and used to estimate their oral RfD of 0.0003 mg/kg/day

). Special Sensitivity = 10 UF = 100 (10x inter
species extrapolation, 10x intra
- species variation) Target MOE = 1000 Open Literature Study Vos et al. , (1990) Immunotoxicity of bis(tri
- n -butyltin)oxide in the rat: Effects on thy

mus - dependent immunity and on nonspecific resistance following long
- term exposure in young vs aged rats. Toxicol. Appl. Pharmacol. 105:144
- 155. NOAEL = 0.025 mg/kg/day LOAEL = 0.25 mg/kg/day based on immunotoxicity (depression of IgE titers and increas e in T. spiralis larvae in muscle) following 4 months and 16.5 months of exposure to Tributyl Tin Oxide. (Review by EPA/IRIS, 1997).Page 12 of 43



### Exposure Scenario Dose Used in Risk

Assessment (mg/kg/day) Special Sensitivity*,

UF , Target MOE, for Risk Assessment Study and Toxicological Effects

Dermal (all durations) BMD 10 = 0.03

mg/kg/day based on immunosupression (established by EPA/IRIS and used to estimate their oral RfD of 0.0003 mg/kg/day

). Special Sensitivity = 10 UF = 100 (10x inter
species extrapolation, 10x intra
- species variation) Target MOE occ. = 100 Target MOE res. = 1000 Open Literature Study Vos et al. , (1990) Immunotoxicity of bis(tri
- n -butyltin)oxide in the rat: Effects on thy

mus - dependent immunity and on nonspecific resistance following long
- term exposure in young vs aged rats. Toxicol. Appl. Pharmacol. 105:144
- 155. NOAEL = 0.025 mg/kg/day LOAEL = 0.25 mg/kg/day based on immunotoxicity (d epression of IgE titers and increase in T. spiralis larvae in muscle) following 4 months and 16.5 months of exposure to Tributyl Tin Oxide. (Review by EPA/IRIS, 1997). Inhalation (all durations) BMD 10 = 0.03

mg/kg/day based on immunosupression (establi shed by EPA/IRIS and used to estimate their oral RfD of 0.0003 mg/kg/day

). Special Sensitivity = 10 UF = 100 (10x inter
species extrapolation, 10x intra
- species variation) Target MOE occ. = 100 Target MOE res. = 1000 Open Literature Study Vos et al. , (1 990) Immunotoxicity of bis(tri
- n -butyltin)oxide in the rat: Effects on thy

mus - dependent immunity and on nonspecific resistance following long
- term exposure in young vs aged rats. Toxicol. Appl. Pharmacol. 105:144
- 155. NOAEL = 0.025 mg/kg/day LOAEL = 0. 25 mg/kg/day based on immunotoxicity (depression of IgE titers and increase in T. spiralis larvae in muscle) following 4 months and 16.5 months of exposure to Tributyl Tin Oxide. (Review by EPA/IRIS, 1997). Dermal Absorption Although there is no guideline dermal toxicity study (range
- finding study only) and no

acceptable dermal absorption study (75% recovery of 113 Sn
- tributyltin oxide), a 15% dermal absorption factor for tributyltin oxide has been used (EPA/HED) for route
- to - route extrapolation. UF = uncertainty factor, NOAEL = no observed adverse effect level, LOAEL = lowest observed adverse effect level,Page 13 of 43

RfD = reference dose, MOE = margin of exposure, NA = Not Applicable 

### * The S pecial Sensitivity factor is applied to a selected dose if there is evid ence of increased susceptibility to children from non
- dietary exposures to pesticides. Several published literature show that tributyltin oxide causes depression of immune functions dependent on the thy mus, particularly in young animals. This is a critic al effect that occurs at doses lower than those causing other toxicities. Therefore, application of this factor provides adequate protection to the most sensitive population, children. 

### 4.0 RESIDENTIAL EXPOSURE ASSESSMENT 4.1 Summary of Registered Uses There are registered products containing TBT that can come in contact with adults and/or children. For example, there are TBT products that can be applied directly by the homeowner . The consumer product s include EPA Reg. No s . 577 - 539, 577 - 544, 1022 - 511, 7313 - 6, 8177 - 71, 9339 - 14 that are for preserving wood such as siding, shingles, fences, decks, millwork, etc. Articles treated with T B T in occupational settings may also have the potential for post
application residential exposure. For example, there are TBT treated articles such as textiles including mattress pads, ticking, and covers. Additionally, there are labels such as 3090
- 123 listing textile treatments with restrictions for no food contact or diapers. However, there are no other clothing restrictions, and therefore, it is assumed clothing worn by adults and/or children can be treated. 4.2 Residential Exposure The exposure scenarios assessed in this document for the representative uses of T B T selected by EPA are listed in Table 4.1. The table also shows the maximum application rate associated with the representative use and the EPA label registration number. Handler dermal and inhalation exposures are assessed for the wood preservative use . Post - application dermal, inhalation, and/or incidental ingestion exposures are assessed for treated articles including clothing and mattress . Post - application/bystander i nhalation exposures are expected to be minimal for most uses, except for drift occurring during the airless spray painting. The inhalation bystander exposure to aerosols generated during painting are assumed to be less then that of the applicator and are therefore not assessed separately .Page 14 of 43



### Table 4.1. Representative Uses Associated with Residential Exposure to T B T . Representative Use Application Method Exposure Scenario Example Registration Number Application Rate Wood Preservative · Brush and a irless sprayer (Note: dip not assessed separately) ST Handler: adult

dermal and inhalation. 1022 - 511 ( 577 - 539, 577 - 544, 1022 - 511, 7313 - 6, 8177 - 71 ) 0.0 62 lb ai/gallon

[ 8.3 lbs per gal density x 0.75 % ai = 0.0 62 lb ai/gallon of st ain] Textiles (a) (exposures to treated articles are represented by exposure to clothing and mattress ) · NA a ST Post
- app: wearing treated clothing, adult dermal; child incidental ingestion and dermal

ST Post
- appl: Sleeping on treated mattress ; adult dermal and child incidental ingestion and dermal 3090 - 123 (textile)

10466 - 24 (mattress) 0.05% ai or 500 ppm TBT

[1% pesticide product by we ight of material treated x 5% ai in formulated product = we ight fraction of 0.0005 ai or 0.05% ai or 500 ppm]
0.056% ai or 560 ppm TBT [3.5% formulated product by weight of goods x 1.6% ai in formulated product = we ight fraction of 0.00056 ai or 0.056% ai or 560 ppm] ( a) The handlers scenarios for textiles we re not assessed for residents because the products can only b e applied occupationally . 

### 4.2.1 Residential Handler Exposures The residential handler scenarios described in Table 4.1 were assessed to determine dermal and inhalation exposures. The scenarios were assessed using PHED data and the equations in Sectio n 1.2, “Criteria for Conducting Risk Assessment.” A summary of the PHED data are presented in Appendix A. Unit Exposure Values : Unit exposure values were taken from the PHED data presented in HED’s Residential SOPs (USEPA, 1997)

· For the airless spra

yer scenario, measured PHED dermal and inhalation unit exposure values for a residential handler applying a pesticide using an airless sprayer to stain the siding of a residential home were used as a surrogate for this scenario . These unitPage 15 of 43



### ungloved exposure values (79 mg/lb a.i. for dermal and 0.83 mg/lb a.i. for inhalation) represent a handler wearing short pants and a short sleeve shirt, with no gloves. · For the brush/roller scenario, measured PHED dermal and inhalation unit exposure values for a residential handler applying a pesticide using a paint brush to the interior of a bathroom were used as a surrogate for this scenario . These unit exposure values (230 mg/lb a.i. for dermal and 0.28 mg/lb a.i. for inhalation) represent a handler wearing short pants and a short sleeve shirt, with no gloves. Quantity handled/treated : The quantities handled/treated were estimated based on information from various sources, including EPA estimates.

n For the brush/roller in paint applications , it is assumed that 20 lb s (approximately 2 gallons) of treated st ain will be used. This is based on the 90 th 

### percentile value of 8 gallons of latex paint used per year divided by the mean frequency of 4 painting events/year. n For the airless sprayer in paint applications , it is assumed that 150 lbs (approximately 15 gallons) of treated st ain will be used. This is based on the coverage of approximately 200 ft2

### /gallon and a house size of 40 x 30 x 20 ft (surface area of 2,800 ft2 

### ). Duration of Exposure: The duration of exposure for most handler homeowner uses is believed to be best represented by the short
- term duration (1 to 30 days). The reason that short term duration was chosen to be assessed is because painting is episodic in nature, not daily . In addition, homeo wners are assumed to use different products with varying activities, not exclusively TBT treated products (e.g., in
- can paint preservative). Results The resulting short
- term inhalation and dermal exposures and MOEs for the representative residential han dler scenarios are presented in Tables 4.2. The calculated inhalation and dermal MOEs are below the target MOE of 10 0 0 for all scenarios. Therefore, the risks exceed EPA’s level of concern. Table 4.2 TBT Short- Term Residential Handler Inhalation and Dermal MOEs. Unit Exposure (mg/lb a.i.) Daily Dose

(mg/kg/day) c MOE d

(Target MOE = 1 0 00) Exposure Scenario Application Method Application

Method Application Rate a Quantity Handled/ Treated per day

b Inhalation Dermal Inhalation Dermal Inhalation Dermal Paint brush 2 gallons 0.28 230 5E - 4 0. 06 1 60 <1 Staining/ Painting Airless

sprayer 0.0 62 lb ai/gal 15 gallons 0.83 79 0.011 0.16 3 <1 a Application rates are the maximum application rates determined from EPA registered label for TBT (i.e., 0.7 5% ai in EPA Reg. No. 1022
- 99; next highest rate is 0.5% ai) . b Amount handled per day values are estimated.Page 16 of 43

c Daily dose (mg/kg/day) = [unit exposure (mg/lb a.i.) x application rate (lb ai/gal) x quantity treated (gal/day) x

absorption factor (10 0% for i nhalation and 15% dermal)]/ Body weight (70 kg). d MOE = NOAEL / Daily Dose. [Where short
- term inhalation and dermal BMD 10 = 0.03 mg/kg/day]. Target MOEs =

10 0 0. 

### 4.2.2 Residential Post- application Exposures For the purposes of this screening level assessment, post
- application scenarios represent a high end exposure scenario for all products represented. As shown in Table 4.1, representative post - application scenarios assessed include wearing treated clothing and sleeping on mattresses (dermal exposure to adults and children and incidental oral exposure to children). 4.2.2.1 Textiles Dermal Exposure to Adults and Toddlers from Contacting Treated Clothing There is the potential for dermal exposure to adults and children from wearing clothing treated during manufacturing with TBT as a preservative (i.e., bacteriostatic/fungistatic ). A post
application assessment assuming no laundering by the homeowner was conducted as a conservative measure (i.e., the effe ct on dislodgeable residues over time during washing is not quantifiable at this time). It should be noted that not all articles of clothing are treated with TBT products or worn on a continuous basis. In general, it is believed that most treated textile s used in a residential setting will result in exposures occurring over a short
- term time duration (1 to 30 days) because residents are assumed to be exposed to treated textiles with vary ing active ingredients, not exclusively TBT treated textiles. Noneth eless, the short
- term dermal toxicological endpoint is protective of the intermediate
- and long
- term duration s because the same endpoint value is used to assess all durations. Exposure Calculations Potential doses are calculated as follows: PDD = W x % applied x % a.i. x % transfer

BW where: PDD = potential daily dose (mg/kg/day ); W = weight of clothing worn (g/day ); % applied = percent of product applied (%); % a.i. = percent active ingredient in product (%); % transfer = p ercent transferred (%); and BW = body weight (kg). AndPage 17 of 43



### W = (SW/SSA) * BSA where: W = weight of clothing worn (g/day ); SW = weight of medium shirt (g); SSA = surface area of medium shirt (cm2 

### ); and BSA = surface area of body covered (cm2 

### ). Assumptions · The formulated product is applied at rates as high 1% by weight of the textiles and the formulated product itself is 5% ai ( 1% formulated product by weight of textile x 5% ai = 0.0 005 weight fraction or 0.05% ai in textiles or 500 ppm TBT in textiles ). · The median surface area of clothing contacting skin for a 3
- ye ar - old toddler is 5,670 cm2 

### (total body surface area minus the head) (USEPA, 1997). For adults, the median surface area is 16,900 cm2 

### (total body surface area minus the head) (USEPA, 1 997). · The textile density is 10 mg/cm2 

### based on the density of mixed cotton and sy nthetics (HERA 2003). It is assumed that the mixed cotton/sy nthetic is used to cover the body for both adults and toddlers, minus the head surface area. Therefore, the to tal amount of fabric worn per day is equal to the density of the fabric (10 mg or 0.01 grams per cm2 

### ) times the surface area covered (5,670 cm2 

### for toddlers, 16,900 cm2 

### for adults), or 56.7 g/day for toddlers, and 169 g/day for adults. · Potential doses were in i tially calculated using a conservative residue transfer factor of 100%, which assumes that all residues are transferable from clothing surfaces to the skin. In cases where the MOEs did not meet the Agency ’s target MOE, potential doses were also calculated using a less conservative residue transfer factor of 5%, which is based on the amount of residue assumed to be transferable from carpeted surfaces (USEPA, 2000 and 2001). In these cases, confirmatory data are needed to support the use of the lower transfer factor. In this revised assessment, two mattress ticking leaching studies were submitted for TBTO. Although these studies used mattress ticking, not clothing, it does provide measured residues transferred from a fabric. In the first study (Thomson Research Associates Report No. RG
- 2002 - 03 - 01) , Ultra
- Fresh 300DN was applied at 2.58% formulated product (1 % TBTO in product) to the mattress ticking. Exposure was simulated using an artificial sweat solution applied to a piece of poly /cotton fabric, we ighted, and rolled over the treated mattress ticking 350, 700, and 1,400 times to simulate exposure for 1, 2, and 4 weeks, respectively . This simulated 50 movements per night for an individual. The results of this study indicated up to 0.41 ug/cm2 

### was transferred from the mattress ticking when simulated for 4 weeks . Therefore, the amount available on a daily basis is 0.41 ug/cm2 

### / 28 days = 0.015 ug/cm2



### . A second study (Thomson Research Associates Report No. RG
- 2004 - 03 - 01) applied 1.72% formulated produ ct (1 % TBTO in product) and monitored the residue transfer using a less abrasive monitoring technique . The second study indicated no leaching of TBTO residues (LOD = 10 ppb). In sufficient information was available in the second study to calculate the am ount of TBTO in ug/cm2 

### transferred from the mattress ticking (i.e., weight of material not provided to convert the 10 ppb concentration to ug/cm2 

### ). Therefore, MOEs at 1⁄2 LODPage 18 of 43



### are not presented. The first study was designed to simulate the “worst
- case” of residue transfer as a screening
- level assessment. The methodology for the “worst
- case” scenario was then refined to attempt to develop a “reasonable worst
- case”. However, neither method provided information linking residue transfer to actual human exposure. The first study appears to be representative of the high end residue transfer to be used as a screening
- level assessment. But there is insufficient information available in the second study to assume that a reasonable certainty of no harm would occur from a child exposed to TBTO
- treated fabric using the methodology of the second study . This revised TBT assessment would have provide d a range of risks from these two studies if the LOD of 100 ppb could be converted to ug/cm2 

### . Nonetheless, the second stu dy can not be confirmed as being designed to represent a reasonable certainty of no harm and the incidental oral component of the treated clothing would still be the risk driver for this use on textiles . Note: The application rates in these studies (i.e. , 2.58% and 1.72% by weight product containing 1% TBTO) are less then the maximum labeled rate for TBTO (i.e., 5% product by weight containing 1% TBTO). · Toddlers (3 years old) are assumed to weigh 15 kg. This is the mean of the median values for male and f

emale toddlers (USEPA, 1997). For adults, a body weight of 70 kg has been assumed. (USEPA, 1997). Results The calculations of the short
- term dermal doses and MOEs for adults and toddlers wearing treated clothing are shown in Table 4. 3 . The dermal MO Es for adults and toddlers are less than the target MOE of 10 0 0 assuming a 100% and 5% residue transfer factor s and the results of one of the two TBTO leaching studies . Note: A second study indicated that the residue transfer was less then 10 ppb ; however there i s insufficient information in the study to convert the 10 ppb to ug/cm2 

### and it is not possible to determine if the second study is representative of a high end exposure potential . Therefore, the risks are of concern.Page 19 of 43

a. Weight of clothing worn (g/day) = (Density of fabric 0.01 g/cm 2 ) * (surface area of body covered, cm 2 ) * 1 outfit/day b. Absorbed Daily Dose (mg/kg/day) = [(weight of clothing worn, g/day) * (percent a.i. in product, %) / 100 * (percent of product appli ed, %) / 100 * (percent residue transferred from clothing to skin, %) * (dermal absorption factor, 0. 1 5 ) * (conversion factor, 1000 mg/g)] / (body weight, 15 kg child and 70 kg adult).

– or -- Absorbed daily dose (mg/kg/day) = Surface area exposed (cm2) x measured residue (ug/cm2) x 15% dermal abs x unit conversion ug to mg (1/1000) x (1/15 kg child BW). c. Dermal MOE = BMD 10 (mg/kg/day) / Daily Dose [Where dermal BMD 10 = 0 .03 mg/kg/day]. Target MOE = 1 0 00. 

### Incidental Oral Exposure to Toddlers Mouthing Treated Textiles (Clothing/Blankets) Exposure Calculations There is the potential for incidental oral exposure to toddlers from mouthing textiles treated with T B T . Potential doses are calculated as follows: PDD = C x SE x SA BW where : PDD = potential daily dose (mg/kg/day ); C = concentration on clothing (mg/cm2 

### ); SE = saliva extraction efficiency (%); SA = surface area mouthed (cm2

### /day ); and BW = body weight (kg). Table 4. 3 : Dermal Post- ap plication Exposures and MOEs for Toddlers and Adults Contacting Treated Clothing Exposure Scenario Weight of

clothing worn (g/day) a Surface Area

Exposed (cm2) Measured

Residue (ug/cm2) Percent residue

transferred from clothing to skin (%) Daily dose b

(mg a.i./ kg/day) Dermal MOE c

(Target MOE=10 0 0) Maximum Labeled Rate: 5% product by w eight (product containing 1% TBTO) 100 0.284 <1 Toddler 56.7 5,670 NA 5 0.0142 2 100 0.181 <1 Adult 169 16,900 NA 5 0.0091 3

Study #1 Application Rate: 2.58% product by w eight (product containing 1% TBTO) Toddler NA 5,670 0.015 NA 0.00085 35

Study #2 Application Rate: 1.72% product by w eight (product containing 1% TBTO) Toddler NA 5,670 <10 ppb NA Need more information to convert LOD of 10 ppb to ug/cm2Page 20 of 43



### And C = % a.i. x % applied x W where: C = concentration on clothing (mg/cm2 

### ); % applied = percent of product applied (%); % a.i. = percent ac tive ingredient in product (%); and W = weight of clothing (m g/ c m 2 

### ). Assumptions · The formulated product is applied at rates as high1% by weight of the textiles and the formulated product itself is 5% ai (1% formulated product by weight of textile x 5% ai = 0.0005 weight fraction or 0.05% ai in textiles or 500 ppm TBT in textiles). · The textile density is 10 mg/cm2 

### based on the density of mixed cotton and sy nthetics (HERA 2003). · The saliva extraction efficiency was 50% (USEPA, 2000 and 2001). · The surface area of textiles mouthed by toddlers is 100 cm2 

### (professional judgment). · Toddlers (3 years old) are used to represent the 1 to 6 year old age group. For three
- ye ar olds, the median body weight is 15 kg (USEPA, 1997). Results Table 4. 4 shows the calculation of the short
- and intermediate
- term oral dose and oral MOE for toddlers mouthing treated textiles. The MOE value is less than target MOE of 1 0 00 for the maximum concentration allowed on the label (MOE is ). Table 4. 4 : Incidental Oral Exposures and MOEs for Toddlers Wearing Treated Textiles (Clothing/Blankets) Weight of clothing (g/cm2 ) % Product

Applied Concentration

on clothing a (mg/cm2 ) Surface are a

mouthed (cm2/day) Saliva

extraction efficiency (%) Potential daily

dose (mg a.i./kg/day) Incidental Oral

MOE c (Target MOE

= 10 00) 0.01 1 % 0.005 100 50 0.017 2
a. Concentration on clothing (mg/cm 2 ) = (5 percent a.i. in product, %) / 100 * ( 1 percent product applied, %) / 100 * (weight of clothing, g/cm2 ) * 1,000 mg/g b. Potential Daily Dose (mg/kg/day) = (concentration on clothing, mg/cm 2 ) * (surface area mouthed, cm 2/day) * (saliva extraction efficiency, %)/100 / (body weight, 15 kg). c Oral MOE = BMD 10 (mg/kg/day) / Potential Daily Dose [Where short
- and intermediate
- term incidental oral BMD 10 = 0.03 mg/kg/day]. Target MOE = 10 0 0. 

### Note: The dermal and incidental oral exposure occurring from textiles sh ould also be reported as a total exposure (i.e., dermal and oral combined) because of the same toxicological effect is used for both routes of exposure. However, the two routes of exposure were not combined at this time because the risks are of concern individually .Page 21 of 43



### 4.2.2.2 Mattresses Mattress pads, ticking , and m attress covers can be treated with TBT during the manufacturing process. Therefore post application dermal exposures to treated mattresses may occur. It was assumed that exposure to a textile mattress cov er will represent exposure to all other mattress components. Since the mattress cover is actually impregnated with TBT both short
- and intermediate
- term exposures durations were assessed. Dermal Exposure to Treated Mattress Covers Exposure Calculations Short- and Intermediate - term exposures - There the potential for short
- and intermediate
- term exposures leading to systemic effects when adults and children come into contact with mattress covers treated with TBT , through the regular use of the mattress . Dermal e xposures and MOEs were calculated for children and adults contacting treated mattresses in residential homes. To determine short and intermediate
- term exposures to TBT in mattresses, the following equation was used: PDD = D x WF1 x WF2 x PF x SA x DA

BW where: PDD = Potential daily dose (mg/kg/day ) D = Mattress textile weight density (mg/cm2 ) WF 1 = Weight fraction of TBT in the mattress cover (% ) WF 2 = Wei ght fraction of TBT transfer red from the mattress cover to skin (cover) PF = Protection factor from single layer of clothing/sheet (%) SA = Body surface area contacting mattress (cm2/day ) DA = Dermal absorption (%) BW = Body weight (kg) 

### Assumptions

· Mattress covers are treated at the rate of 3.5% fo rmulated product by weight of goods x 1.6% ai in formulated product = weight fraction of 0.00056 ai or 0.056% ai or 560 ppm (EPA Reg. No. 10466 - 24). · The mattress cover density is assumed to be 1 0 m g/cm2 

### based on the density of mixed cotton and sy nthetics ( HERA 2003). · In the initial TBT assessment, default residue transfer factors of 100% and 5% were used. In this revised assessment, two mattress ticking leaching studies were submitted for TBTO. I n the first study (Thomson Research Associates Report No. RG
- 2002 - 03 - 01), Ultra
- Fresh 300DN was applied at 2.58% formulated product (1 % TBTO in product) to the mattressPage 22 of 43



### ticking. Exposure was simulated using an artificial sweat solution applied to a piece of poly /cotton fabric, weighted, and rolled over the treat ed mattress ticking 350, 700, and 1,400 times to simulate exposure for 1, 2, and 4 weeks, respectively . This simulated 50 movements per night for an individual. The results of this study indicated up to 0.41 ug/cm2 

### was transferred from the mattress ticking when simulated for 4 weeks. Therefore, the amount available on a daily basis is 0.41 ug/cm2 

### / 28 days = 0.015 ug/cm2 

### . A second study (Thomson Research Associates Report No. RG
- 2004 - 03 - 01) applied 1.72% formulated product (1 % TBTO in product) and moni tored the residue transfer using a less abrasive monitoring technique. The second study indicated no leaching of TBTO residues (LOD = 10 ppb). In sufficient information was available in the second study to calculate the amount of TBTO in ug/cm2 

### transferre d from the mattress ticking (i.e., weight of material not provided to convert the 10 ppb concentration to ug/cm2 

### ). Therefore, MOEs at 1⁄2 LOD are not presented. The first study was designed to simulate the “worst
- case” of residue transfer as a screening
- le vel assessment. The methodology for the “worst
- case” scenario was then refined to attempt to develop a “reasonable worst
- case”. However, neither method provided information linking residue transfer to actual human exposure. The first study appears to be representative of the high end residue transfer to be used as a screening
- level assessment. But there is insufficient information available in the second study to assume that a reasonable certainty of no harm would occur from a child exposed to TBTO
- treated fabric using the revised methodology . This revised TBT assessment would have provided a range of risks from these two studies if the L OD of 100 ppb could be converted to ug/cm2 

### . Nonetheless, the second study can not be confirmed as being designed to represent a reasonable certainty of no harm. Note: The application rates in these studies (i.e., 2.58% and 1.72% by weight product containing 1% TBTO) are less then the maximum labeled rate for TBTO (i.e., 3. 5% product by weight containing 1 .6 % TBTO). · Th e protection factor reducing exposure to TBT residues in the mattress from the use of a sheet or clothing is 50% based on PHED protection factor for a single layer of clothing (US EPA 1998). · The child skin area contacting the mattress was assumed to 3,283 cm2 

### (50% of the total surface area of a toddler) (NAFTA guidance per US EPA 1997 ). · The adult skin area contacting the mattress was assumed to 9,220 cm2 

### (50% of the total surface area of an adult) (NAFTA guidance on surface areas per US EPA 1997 ). · The chemi cal specific dermal absorption study is 15% . · The body weight of a child was assumed to be 15 kg. · The body weight of an adult was assumed to be 70 kg Results Table 4. 5 shows the calculation of the short and intermediate
- term dermal exposures and MOEs for children and adults contacting treated mattress covers. The dermal MOEs are below the t arget MOE of 1 0 00, and therefore are of concern for adults and children contacting the cover and assuming 100% and 5% transfer to skin and the results of one of the tw o TBTO leaching studies. Note: A second study indicated that the residue transfer was less then 10 ppb; howeverPage 23 of 43



### there is insufficient information in the study to convert the 10 ppb to ug/cm2 

### and it is not possible to determine if the second study is representative of a high end exposure potential. Therefore, the risks are of concern. Table 4. 5 . Short - and Interm ediate - term Derm al Exposure s and MOE s for Children and Adults Contacting Treated Mattress Covers

Duration % a.i. Mattress

density (mg/cm2 ) F raction

transferred to skin Skin surface

area contacting mattress (cm2/day) Protective

factor (%) Dermal

Absorption (%) ST and IT

Exposure a (mg/kg/day) Dermal MOE

(Target MOE

= 10 0 0 ) b Children 100% 3,283 50% 1 5 % 0.092 <1 ST/IT 0.056

% 10 5% 3,283 50% 1 5 % 0.0046 7 Adults 100% 9,220 50% 1 5 % 0.055 <1 ST/IT 0.056

% 10 5% 9,220 50% 1 5 % 0.0028 11 Study #1 Application Rate: 2.58% product by w eight (product containing 1% TBTO) ST/IT Children 0.026

% NA 0.015

ug/cm 2 3,283 50% 15% 0.0037 8 Study #2 Application Rate: 1.72% product by w eight (product containing 1% TBTO) ST/IT Children 0.017

% NA <10 ppb 3,283 50% 15% Need more information to convert LOD of 10 ppb to ug/cm2 a Equations used to estimate exposure are presented above for estimates based on percent transferred. For study numbers 1 and 2 the absorbed daily dose (mg/kg/day) = Surface area exposed (cm 2 ) x measured residue (ug/cm 2 ) x 15% dermal abs x 50% protection factor from sheets x unit conversion ug to mg (1/1000) x (1/15 kg child BW). B Dermal MOE = BMD10 / dermal dose [Where: ST and IT dermal BMD10 = 0.03 mg/kg/day ; Target MOE = 1000 ]. 

### 4.2.3 Data Limitations/Uncertainties There are several data limitations and uncertainties associated with the residential handler and post
- application exposure assessments. These include the following:

· Surrogate dermal and inhalation unit exposure values were taken from the Pesticide Handler Exposure Database (USEPA, 1998) (See Appendix B for summaries of the data source). Some of the PHED data are of poor quality, therefore, EPA requires that confirmatory monitoring data be generated to support the values used in these assessments. · The quantities handled/treated were estimated based on information from various sources, including HED’s Standard Operating Procedures (SOPs) for Residential Exposure Assessments (USEPA, 2000 and 2001). In certain cases, no standard values were availablePage 24 of 43



### for some scenarios. Assumptions for these scenarios were based on EPA estimates and could be further refined from input from registrants. · Two residue transfer studies were submitted for TBTO. Both studies reported results for the mattress ticking. The data are also used in this review for estimating risks to the clothing. The first of two studies was designed to simulate the “worst
- case” of residue transfer as a screening
- level assessment. The methodology for the “worst
- case” scenario was then refined to attempt to develop a “reasonable worst
- case”. However, neither method provided information linking residue transfer to actual human exposure. The first study appears to be representative of the high end residue transfer to be used as a screening
level assessment. But there is insufficient information available in the s econd study to assume that a reasonable certainty of no harm would occur from a child exposed to TBTO
treated fabric using the revised methodology . This revised TBT assessment would have provided a range of risks from these two studies if the LOD of 100 ppb could be converted to ug/cm2 

### . Nonetheless, the second study can not be confirmed as being designed to represent a reasonable certainty of no harm. Note: The application rates in these studies (i.e., 2.58% and 1.72% by weight product containing 1% TBT O) are less then the maximum labeled rate s for TBTO . 5.0 RESIDENTIAL AGGREGATE RISK ASSESSMENT AND CHARACTERIZATION The inhalation, dermal, and oral endpoints are based on the same toxicological study /effects, and therefore, it would be appropriate to estimate aggregate MOEs. The residential uses that could potentially be aggregated are the paint applications , the textiles , and the mattresses . There is the likelihood of co
- occurrence for two of the uses but it would be unlikely that all three uses would c o - occur because of the limited frequency a resident paints coupled with not all paints and/or textiles are treated with TBT . Therefore, residential uses could be aggregated for two of the uses . However, at this time the risks are of concern for each of the individual uses, and therefore, there is no need to aggregate the risks. 6.0 OCCUPATIONAL EXPOSURE ASSESSMENT The exposure scen arios assessed in this document for the representative uses selected by EPA are shown in Table 6.1. The table also shows the maximum application rate associated with the representative use and the appropriate EPA Registration number for the product label. It should be noted that for the calculation of application rates in which 8.34 lb/gal is noted, the product is assumed to have the density of water because no product
- specific density is available. Potential occupational handler exposure for T B T can o ccur in six Use Categories: agricultural premises and equipment; commercial/institutional/in dustrial premises and equipment; material preservatives ; and industrial processes and water systems ; antifoul ing coatings; and wood p reservatives .Page 25 of 43



### Table 6.1. Re presentative Exposure Scenarios Associated with Occupational Exposures to TBT Representative Use Method of Application Exposure Scenario Example Registration # Application Rate Agricultural Premises and Equipm ent (Use Category I) Agricultural/farm

/ poultry structures/buildings and equipment Brush , mo p, wipe,

spray , and fogger for poultry farm buildings and poultry hatcheries (incubators, hatchers, hatchery rooms) ST/IT Handler: Inhalation Dermal 65020 - 12 Liquid: 0.00033 lb ai/gal [ ( 0.5 oz formulated pro duct x 1 % ai x 8.34 lb/128 oz ) / ( 1 gal water) = 0.00033 lb ai/gal] Fogger: 1.3E - 6 lb ai/ft3 [ ( 1 gal formulated product x 8.34 lb/gal density x 1 % ai ) / (6000ft2 x 10 ft ceiling) = 1.3E - 6 lb ai/ft 3 as the maximum rate representing poultry farm building s] Com me rcial/Industrial/Institutional Premises (Use Category III) (See wood preservative category for commercial painters using treated stain) NA NA NA NA

Material Preservatives (Use Category VII) C aulks, sealants, adhesives, etc Liquid pour

Metered p ump ST/IT Handler:

Inhalation dermal 5383 - 47

(67360
- 3, 1529 - 30, and 1529 - 35) 0.145% ai

[0.5% formulated product x 29% ai = 0.145% ai or 1450 ppm ai] MWF Liquid pour

Machinist ST/IT/LT

handler/machinist: Dermal Inhalation 5383 - 47 0.145% ai in cutting oil [0.5% formulated product x 29% ai = 0.145% ai or 1450 ppm ai ] Industrial processes and Water S ystem s (Use Category VIII) Pulp and Paper Metered pump ST/IT Handler: Inhalation dermal 47371 - 29 Initial: 0.0 14 lb ai/ton Continuous: 0.0 07 lb ai/ton [ Initial : 9.6 oz/ton paper Continuous feed : 4.8 oz/ton p aper . Where 9.6 oz product x 2 .2 5% ai x 8.34 lb/128 oz = 0.014 lb ai/ton paper ]Page 26 of 43



### Table 6.1. Re presentative Exposure Scenarios Associated with Occupational Exposures to TBT Representative Use Method of Application Exposure Scenario Example Registration # Application Rate Recirculating Cooling Water Liquid pour

Metered pump ST/IT Handler:

Inhalation dermal 5 185 - 399 Initial: 0.089 lb ai/1000 gal Continuous : 0.022 lb ai/1000 gallons of water [ Initial: 40 oz product x 8.34 lb/128 oz x 3.4% ai /1000 gal lons water Continuous feed: 10 oz product x 8.34 lb/128 oz x 3.4% ai /1000 gallons water ] Oil fields and petrochemical water injection systems Liquid pour

Metered pump ST/IT Handler:

Inhalation dermal 5185 - 399 Initial: 0.089 lb ai/1000 gal Continuous: 0.022 lb ai/1000 gallons of water [ Initial: 40 oz product x 8.34 lb/128 oz x 3.4% ai /1000 gallons water Continuous feed: 10 oz product x 8.34 lb/128 oz x 3.4% ai /1000 gallons water] Antifouling Coatings (Use Category IX) Sonar Domes & Hulls Unknown ST/IT Handler: Inhalation Dermal (assumed) 1225 - 11

74489 - 01 5.78 % ai in formulation

53% ai in formulation Wood Preservatives (Use Category X) Staining (commercial painters) Paint brush,



### Airless sprayer ST/IT Handler:

Inhalation Dermal 1022 - 511

( 577 - 539, 577 - 544, 1022 - 511, 7313 - 6, 8177 - 71 ) 0.062 lb ai/gallon

[8.3 lbs per gal density x 0.75% ai = 0.062 lb ai/gallon of stain]


### 6.1 Occupational Handler Exposures The occupational handler scenarios included in Table 6.1 were assessed to determine inhalation and dermal exposures. The general assumptions and equations that were used to calculate occupational handler inhalation and dermal risks are provided in Section 1.2, Criteria for Conducting the Risk Assessment. The majority of the scenarios were assessed using CMA data and Equations 1
- 3. However, for the occupational scenarios in which CMA data were insufficient, other data and methods were applied.Page 27 of 43



### Unit Exposure Values (UE): Inhalation and dermal unit exposure values were taken from the proprietary Chemical Manufacturers Association (CMA) antimicrobial exposure study (USEPA, 1999b: DP Barcode D 247642) or from the Pesticide Handler Exposure Database (USEPA, 1998).

· For the mopping scenario, the CMA dermal and inhalation unit exposure values for ungloved mopping were used (71.6 mg/lb a.i. and 2.38 mg/lb a.i., respectively ). These values are based on data collected from six replicates in which the applicator mopped the floor and received exposure via contact with the mop or with the bucket. · For the wiping scenario, the CMA dermal and inhalation unit exposure values for ungloved wiping were used ( 2,870 mg/lb a.i. and 67.3 mg/lb a.i., respectively ). These values are based on data collected from six replicates (dental technicians) who used a finger pump sprayer to apply the product and then wiped the surfaces with a paper towel · For the low pressure handwand scenarios, the CMA dermal and inhalation unit exposure values for ungloved use of a low pressure spray were used (191 mg/lb a.i. and 0.681 mg/lb a.i., respectively

). These values are based on data collected from eight replicates in which the appl icator hand sprayed carpet using 200 psi, then used a push broom rake to raise the carpet nap . · For the high -

pressure spray scenario, the PHED dermal and inhalation unit exposure values for liquid/open pour/high pressure spray (PHED scenario 35) were used ( single layer of clothing and gloves). The dermal and inhalation unit exposure values are 2.5 mg/lb a.i. and 0.12 mg/lb a.i., respectively .
· For the liquid pour scenarios for materials preservatives, the unit exposure depends on the material being treated. The following CMA unit exposures were available and used for the assessment of the risk associated with the treatment of the specified materials. o Metalworking fluid : CMA metal fluid gloved data. The dermal UE is 0.184 mg/lb a.i. and the inhalation UE is 0.00854 mg/lb a.i.. The values are based on 8 replicates where the test subjects were wearing a single layer of clothing and chemical resistant gloves. o Sealants, caulks, grout, etc : CMA preservative gloved data. The dermal UE is 0.135 mg/lb a.i. and the inhalation UE is 0.00346 mg/lb a.i.. The values are based on 2 replicates where the test subjects were wearing a single layer of clothing and chemical resistant gloves. Although this unit exposure is based on minimal replicates, the exposure value is simil ar to the one found in PHED for a similar scenarios. o Fogging : It is assumed that most of the exposure to the handler will be due to preparing the fogger, and that the handler leaves the room immediately after fogging commences. Therefore, the available CMA disinfectant liquid pour dermal and inhalation unit exposure values were used. The dermal and inhalation unit exposure values are 36.5 mg/lb a.i. and 1.89 mg/lb a.i., respectively . This value is based on data collected from two gloved replicates involving pouring a disinfectant product from a jug into sterilization trays designed for dental instruments, adding water and instruments to the tray, removing the instruments, and discarding the old solution.Page 28 of 43



### · For the liquid pump scenarios, AD has recently de veloped definitions and exposure methodology guidance when working with closed loading and delivery systems in commercial and industrial settings. Closed loading systems are engineering controls that are “...designed to prevent human exposure and should not require human intervention to eliminate exposure” (CDPR 2003). Closed transfer systems that require the worker to open pour the concentrate into a transfer system are not considered under this definition of closed loading systems because the initial expo sure for the open pour will require a quantitative assessment. Although closed loading and delivery systems are designed to prevent or eliminate exposure, zero exposure is difficult to obtain. Even though analy tical techniques can measure residues at extremely low levels, for practical purposes at some point these residues can be considered negligible or minimal . To account for the fact that some residues are available for dermal contact (and to a lesser degree available for inhalation exposure), EPA is requiring that appropriate PPE be worn by the worker. Negligible exposure can be considered to result from the use of systems that are designed to drip less than 2 mL per coupling as in dry coupling or metering pumps that are closed on both ends. The s econd category, minimal exposure , has been established because some closed systems are not entirely enclosed or have not been engineered to reduce drips to 2 mL, but for practical purposes effectively reduce exposure such that risks are not of concern. Minimal exposure can be considered to result from closed systems that are designed to prevent or eliminate inhalation and dermal exposure but are not engineered to a specification (e.g., volume expected to be discharged). In the case of T B T , EPA expects that occupational exposures will be negligible or minimal assuming that label
- specified PPE (i.e., coveralls, long pants, long
- sleeved shirts, and chemical resistant gloves) and label
- specified closed delivery and loading systems such as dry coupling and c losed system metering pumps are consistently utilized. Therefore, a quantitative exposure and risk assessment is not warranted and the risks can be considered not a concern.

· For roller/brush scenarios, the occupational PHED dermal and inhalation unit exp osure values for paintbrush applications (PHED scenario 22) were used (single layer of clothing). The inhalation exposure value is 0. 28 mg/lb a.i. The dermal unit exposures are 180 mg/lb a.i. for ungloved replicates and 24 mg/lb a.i. for gloved replicates . · For airless sprayer scenarios, the occupational PHED dermal and inhalation unit exposure values for airless sprayer application (PHED scenario 23) were used (single layer of clothing). The inhalation exposure value is 0.83 mg/lb a.i. The dermal unit exp osures are 38 mg/lb a.i. for ungloved replicates and 14 mg/lb a.i. for gloved replicates. Quantity handled/treated : The quantity handled/treated values were estimated based on information from various sources. The following assumptions were made:Page 29 of 43



### · For the low-

pressure handwand scenario , it was assumed that 10 gallons of solution are used in agricultural uses. · For the high -

pressure spray scenario, it was assumed that 40 gallons of solution are used. · For the mopping scenario, it was assumed that two gal lons of solution are used. · For the wiping scenario, it was assumed that 0.26 gallons were used based on standard assumptions of the amount used for hard surface disinfection. · For the fogging scenario in the agricultural use site category , it was assumed th at a poultry house of 600 ft x 66 ft x 10 ft or 39,600 ft 2 area or 396,000 ft3 volume is treated. · For the liquid pour scenarios, the quantity of the chemical that is handled depends on the material that is being treated. The following values were used for the different materials to be treated : o Metalworking fluid : 2,502 lbs (approximately 300 gallons, based on the density of water, 8.34 lb a.i./gal) o Adhesives and Textiles : 10,000 lbs (standard AD assumption). o Oil fields : Up to 5 gallons of product are assumed to be open poured in some instances before a metering system is employed. · For the roller/brush painting scenario, it was assumed that 50 lbs (approximately 5 gallons of paint with a density of 10 lb/gal) of treated stain are used (standard AD a ssumption). · For the airless sprayer in the painting scenario, it was assumed that 500 lbs (approximately 50 gallons of paint with a density of 10 lb/gal) of treated stain are used. (standard AD assumption). Duration of Exposure : The MOEs were calculated f or the short
- and intermediate
- term durations for occupational handlers using the appropriate endpoints in Table 3.2. Exposure Calculations and Results The resulting inhalation and dermal exposures and MOEs for the representative occupational handler scenarios are presented in Table 6.2. In summary, fo r the non fogging agricultural uses the inhalation MOEs are greater than 100, and therefore not of concern. Some of the dermal MOEs for the same scenarios are above and some below the target MOE of 100 . However, the use of chemical resistant gloves was not assessed for all scenarios because the data were not available. Based on the low application rate (i.e., 0.00033 lb ai/gallon), the magnitude of the MOEs, and assuming that chemical resistant gloves would afford substantial reduction in exposure, these dermal MOEs do not appear to be of concern if gloves are required on the labels (confirmatory data would be required). The MOEs for the material preservative use are below the target MOE of 100. Potential mitigation for material preservative additives would be to require closed loading systems. The industrial process and water system uses also need to be restricted to closed loading systems. At this time, it is unclear how the antifouling coatings a re applied and additional information on the application techniques are requested. Finally, the commercial application of stains indicate MOEs of concern (i.e., MOEs less than 1).Page 30 of 43



### Table 6.2. Short- and Intermediate - Term Risks Associated with Occupation al Handlers Unit Exposure (mg/lb a.i.) Daily Dose (mg/kg/day) a MOE b

(Target MOE = 100) Exposure Scenario Method of

Application Inhalation Dermal Applicatio n Rate Quantity

Handled/ Treated per day Inhalation Dermal Inhalation Dermal Agricultural Premises and E quipment (Use Site Category I ) Brush
- on 0.28 180 no gloves ( 24 gloves ) 5 gal 6.6E - 6 0.0006 4 4500 47

(350 gloves) Wipe 6 7.3 2870 0.26 gal 8.2E - 5 0.0005 3 360 57 Mop 2.38 71.6 2 gal 2.2E - 5 0.001 1300 300 Spray (hand held) 0.681 191 10 gal 3.2E - 5 0.0014 930 22 Spray (mechanical) 0.12 2.5 0.00033 lb ai/gal
40 gal 2.3E - 5 7.1E - 5 1300 420 Agricultural/farm

/ poultry structures/buildings and equipment
Fogger 1.89 36.5 1.3E - 6 lb ai/ft 3 396,000 ft 3 0.014 0.040 2 <1 Comme rcial, Institutional and Industrial Premises and Equipm ent (Use Site Category III ) (See wood preservative category for commercial painters using treated stain)

Material Preservatives (Use Site Category VII) Liquid pour 0.00346 0.135 (gloves) 2000 lbs 0.00014 0.0008 4 210 36 Caulks, adhesives, grout, etc. (manufacturing process) Liquid pump 0.000403 0.454 0.145% ai 10,000 lbs 8.3E - 5 0.014 360 2 MWF Liquid pour 0.00854 0.184 0.145% ai 300 gal (2,500 lbs) 0.00044 0.0014 68 21 In dustrial Processes and Water Systems (Use Site Category VIII) Pulp and Paper Metering pump 0.000265 0.00454 (gloves) 0.014 lb

ai/ton 500 tons Recirculating Cooling Water Metering pump 0.000265 0.00454 (gloves) 0.089 lb

ai/1000 gal 5E7 gallons Closed loading systems are expected to result in minimal exposure. Specify closed loading system on label along with long pants, long sleeved
- shirts, and chemical

resistant gloves. Pour liquid 0.45 10.1 (gloves) 5 gal product (41.7 lbs) 0.0091 0.031 3 3 Oil fields and petrochemical water injection systems Metering pump 0.000265 0.00454 (gloves) 0.089 lb

ai/1000 gal lons treated (3.4% ai) Up to

420,000 gallons See closed loading language above. Antifouling Paints (Use Site Category IX) Sonar Domes & Hull s Specialty use. Application rates and methods are unknown. Wood Preservatives (Use Site Category X) Painting/staining Paint brush 0.28 180 0.062 5 gallons 0.0012 0.12 24 <1Page 31 of 43



### Table 6.2. Short- and Intermediate - Term Risks Associated with Occupation al Handlers Unit Exposure (mg/lb a.i.) Daily Dose (mg/kg/day) a MOE b

(Target MOE = 100) Exposure Scenario Method of

Application Inhalation Dermal Applicatio n Rate Quantity

Handled/ Treated per day Inhalation Dermal Inhalation Dermal (commercial) Airless sprayer 0.83 38 lb ai/gal 50 gallons 0.037 0.25 <1 < 1
a Absorbed Daily dose (mg/kg/day) = [unit exposure (mg/lb a.i.) x absorption factor ( dermal 0 . 15 ) x application rate x quantity treated / Body weight

(70 kg). b MOE = NOAEL (mg/kg/day) / Daily Dose [Where ST and IT inhalation BMD10 = 0.0 3 mg/kg/day] . Target MOE = 100. 

### 6.2 Occupational Post- application Exposures Occupational post
- application dermal and inhalation exposures are assumed to be negligible except for the machinist exposed to T B T - treated metalworking fluids. Metalworking Fluids: Machinist

There is a potential for dermal and inhalation exposure when a worker handles treated metalworking fluids. This route of exposure occurs after the chemical has been incorporated into the metalw orking fluid and a machinist is using/handling this TBT treated end
product. Dermal Exposures Exposure Calculations Short
- , intermediate
- and long
- term exposure estimates were derived using the 2
- hand immersion model f

rom ChemSTEER. The model is available at www.epa.gov/opptintr/exposure/docs/chemsteer.htm . The 2
- hand immersion equation is as follows: PDR = SA x % a.i. x FT x FQ BW where: PDR = Potential dose rate (mg/kg/day ); SA = Surface area o f both hands plus the forearms (cm2 

### ); % a.i. = Fraction active ingredient in treated metalworking fluid (unitless) FT = Film thickness of metal fluid on hands (mg/cm2 

### ) FQ = Frequency of events (event/day ); BW = Body weight (kg)Page 32 of 43



### Assumptions

· The surface of area of both hands and forearms is 2013 cm2 

### (USEPA 1997) · The body weight of an adult is 70 kg (USEPA 1997) · The percent active ingredient in treated metalworking fluid is 145 0 ppm (i.e., 0.145% ai) calculated from 0.5% formulated product x 2 9 % ai (EPA Registration No. 5383 - 47 ). · For short
- , intermediate
- and long
- term durations, the film thickness on the hands is 1.75 mg/cm2 

### , which was extracted from the document entitled, “A Laboratory Method to Determine the Retention of Liquids on the Surface of Hands” (USEPA 1992). The film thickness methodology represents a machinist immersing both hands in metalworking fluid and then partially cleaning hands with a rag. The film thickness was chosen because the dermal endpoint for short
- , intermediate
- and long
- term durations is based on systemic effects. Inhalation Exposures Exposure Calculations A screening
- level intermediate and long term inhalation exposure estimate for treated metalworking fluids has been developed using the OSHA PEL for oil mist. The equation used for calculating the inhalation dose is: PDR = PEL x IR x % a.i. x ED

BW where: PDR = Potential dose rate (mg/kg/day ); PEL = OSHA PEL (mg/m 3 

### ); IR = Inhalation rate (m 3 /hr

### ) % a.i. = Fraction active in gredient in treated metalworking fluid (unitless) ED = Exposure duration (hrs/day ); BW = Body weight (kg) Assumptions

· The high
- end oil mist concentration is based on OSHA’s Permissible Exposure Limit (PEL) of 5 mg/m 3 

### (NI OSH, 1998). · The percent active ingredient in treated metalworking fluid is 1450 ppm (i.e., 0.145% ai) calculated from 0.5% formulated product x 29% ai (EPA Registration No. 5383
- 47 ). · The inhalation rate for a machinist is 1.0 m 3 /hr 

### . · A machinist is exposed to the metalworking fluid 8 hours a day, for 5 days a week.
· 

### The body weight of an adult is 70 kg (USEPA 1997).Page 33 of 43



### Dermal and Inhalation Results Table 6.3 shows the calculation of the absorbed daily dose and MOE for a machinist working with metalworking fluids. The dermal and inhalation MOE values are be low the target MOE of 100 for all durations. Table 6.3. Short- , Intermediate - , and Long - Term Risks Associated with Postapplication

Exposure to Metalworking Fluids treated with BNS (Machinist) Dermal Inputs Inhalation Inputs Absorbed Daily Dose (mg/kg/day) MOE
% a.i. Hand & Forearm Surface Area (cm 2 ) Film thickness (mg/cm 2 ) Frequency

(event/day) OSHA

PEL (mg/m 3 ) Inhal.

rate (m 3 /hr) Exposure Duration (hrs/day) Dermal a

(mg/kg/day) Inhal ation . b

(mg/kg/day) Dermal MOE

(Target MOE = 100) c Inhalation MOE

(Target MOE = 100) d

0. 14 5 2013 1.75 1 5 1.0 8 0.0 11 0.000 83 3 36

a Dermal Daily Dose (mg/kg/day) = [(% active ingredient * hand & forearm surface area* dermal absorption factor (1)* f ilm thickness (mg/cm 2 )* Frequency (event/day)] / Body weight (70 kg). b Inhalation Daily Dose (mg/kg/day) = % active ingredient * OSHA PEL (mg/m 3 ) * Inhalation rate (m 3 /hr) * exposure duration (hr/day) *

inhalation absorption factor (1)/ body weight (70 kg) c Dermal MOE = BMD 10 (mg/kg/day) / Daily Dose (mg/kg/day) [Where: ST/IT/LT dermal BMD 10 = 0 .03 mg/kg/day; target MOE =

100]. d Inhalation MOE = BMD 10 (mg/kg/day) / Daily Dose (mg/kg/day) [Where: inhalation BMD 10 = 0.03 mg/kg/day for all durations; target

MOE = 100 for all durations] 

### Fogging ( Poultry farm building) Post - application inhalation exposure (to aerosols) was assessed for entry into a poultry farm building after a fogging application. The inhalation exposures and resulting REI s are based on modeling of the aerosols from the maximum application rate. Fogging poultry farm buildings based on the label rate is assumed to be the high end of the air concentrations (mg/m 3 

### ) when fogging the incubators, hatchers, and hatchery rooms . The air conc entration applied and the air exchange rates of the structure are used to estimate the REI s . Therefore, nuances in the treatment of poultry farm buildings versus poultry hatcheries are based on the target air concentration appli cation rate . Any dermal po st application is presumed to be negligible. The inhalation exposure assessment was conducted using the Multi
- Chamber Concentration and Exposure Model (MCCEM v1.2). MCCEM estimates average and peak indoor air concentrations of chemicals released from products or materials in houses, apartments, townhouses, or other residences. Although the data libraries contained in MCCEM are limited to residential settings, the model can be used to assess other indoor environments. The MCCEM model was executed uti lizing the rate of 1.3E - 6 lb ai/ft 3 

### (EPA Reg No. 65020 - 12 states to fog 1 gallon of product per 6,000ft2 

### of floor space and EPA assumed 10 ftPage 34 of 43



### ceilings to calculate an air concentration per volume) for poultry houses. Upon commencement of fogging activities , TBT labels state that the building should be well ventilated and not entered until 1 to 4 hours after fogging. I f the building must be entered, the label stat es individuals entering the building must wear a self
- contained respirator approved by NI OSH/MS HA, goggles, long sleeves and long pants. Therefore, exposure was calculated for a person entering the building 1 , 2, and 4 hours after all the applied fogger has been deployed. The following assumptions were included along with the standard input parameters of the MCCEM model.

· The area being fogged is a one
- chamber barn with dimensions o f 600ft x 66ft x 10ft (AD standard assumption). · For the poultry structures, the air exchange rate is 4 per hour based on the rate for a poultry barn (Jacobson, 2005). · Fo gging occurs instantaneously, so that the entire mass of product is mixed homogeneously with the indoor air as soon as fogging commences. · It is assumed that all of the aerosols are inhalable and/or respirable. A de tailed report is presented in Appendix B, including air concentrations reported for every 10 minutes for several days . Upon entry after 1 hour, the 8
- hour time weighted average (TWA) air concentration for a worker exposed for 8 hours the MOEs is less then the target MOE of 100 (i.e., MOE = 17 ). However, the MOE is greater than the target MOE of 100 if the REI is set at 2 hours and there are 4 air exchange rates per hour (ACH). If specific REI s are warranted for hatcheries that differ from 2 hours, a comparison of the fogging concentration rates (e.g., mg/m 3 

### ) should be discussed during mitigation. Table 22. Short and Interm ediate Term Inhalation Risks Associated with Postapplication Exposure to TBT After Fogging a Poultry House Parameter a Value Rationale Dimensions 600 ft x 66t x10 ft, 39, 600 ft2 floor area, 396,000 ft 3 (11214 m3 ) volume Standard AD assumption Air Changes per Hour (ACH) * 4/hr Jacobson, 2005 Activity Pattern * Time Weighted Average (TWA) starting at expiration of 1 and 4 hr

REI Based on product’s re
- entry interval Concentr ation of Fogging Liquid Not needed lb ai/gal Product Label ( 65020 - 12 )

Use rate 1.3E - 6 lb ai/ft 3 Product label states to fog 1 gal product / 6 000 ft2 x 10 ft ceiling ( ceiling height assumed) Concentration in room after fogging (initial concentration rate at time 0) * 20.61 mg ai/m3 See Appendix B spreadsheet

Body Weight 7 0 kg (adult) NAFTA (USEPA, 1997) Inhalation Rate 1.0 m3 /hr NAFTA Light Activity for Adults (USEPA, 1997) MCCEM OUTPUT 1 hour REI 2 hour

REI 4 hour

REIPage 35 of 43

Table 22. Short and Interm ediate Term Inhalation Risks Associated with Postapplication Exposure to TBT After Fogging a Poultry House Parameter a Value Rationale Concentration after appropriate REI

(mg/m3 ) 0. 377 0.0069 2.3E - 6 MCCEM calculated air concentration 8 - hour Time Weighted Average (TWA) air c oncentration (mg/m3 ) 0.0 16 (TWA from 1 to 9 HAT) 2.9E - 4

(TWA from 1 to 9 HAT) 9.7E - 8

(TWA from 4 to 12 HAT) MCCEM
- calculated 8 - hr TWA air

concentration starting after REI for 8 hour working shift Dose (mg/kg/day) 0.00 18 3.3E - 5 1.1E - 8 ( TWA Air Conc.) x (Exposure Time of 8 hr) x (Inhal. Rate) / BW ( 7 0kg) Short
- term MOE 17 910 2.7E+6 BMD10 (0 .03 mg/kg/day) / Dose *Used as MCCEM input. Default value s from MCCEM were used for all inputs not listed in the table abov e. HAT = hours after treatment. 

### 6.4 Data Limitations/Uncertainties There are several data limitations and uncertainties associated with the occupational handler and post application exposure assessments. These include:

· Surrogate dermal and inhalation unit exposure values were taken from the proprietary Chemical Manufacturers Association (CMA) antimicrobial exposure study (USEPA, 1999: DP Barcod e D247642) or from the Pesticide Handler Exposure Database (USEPA, 1998) (See Appendix B for summaries of these data sources). Since the CMA data are of poor quality, the Agency requires that confirmatory data be submitted to support the occupational scenarios assessed in this document. · The quantities handled/treated were estimated based on information from various sources, including HED’s Standard Operating Procedures (SOPs) for Residential Exposure Assessments (USEPA, 2000 and 2001), and personal commun ication with experts. In particular, the use information for the pulp and paper processing, drilling mud uses, and cooling water tower uses are based on personal communication with biocide manufacturers for these ty

pes of uses. The individuals contacted have experience in these operations and their estimates are believed to be the best available without undertaking a statistical survey of the uses. In certain cases, no standard values were available for some scenarios. Assumptions for these scenarios were based on EPA estimates and could be further refined from input from registrants.Page 36 of 43



### 7.0 REFERENCES USEPA. 1992. A L aboratory Method to Determine the Retention of Liquids on the Surface of Hands, Exposure Evaluation Division, Office of Pollution Prevention and Toxic, USEPA, EPA 747 - R - 92 - 003, September, 1992. USEPA. 1996. Office of Research and Development, Descriptive Statistics Tables from a Detailed Analysis of the National Human Activity Pattern (NHAPS) Data; EPA/600/R
- 96/148, July 1996. Data Collection Period October 1992
- September 1994 . USEPA. 1997. Exposure Factors Handbook. Volume I
- II. Office of Research and Development. Washington, D.C. EPA/600/P
- 95/002Fa. August 1997. USEPA. 1998. PHE D Surrogate Exposure Guide. Estimates of Worker Exposure from the Pesticide Handler Exposure Database Version 1.1. Washington, DC: U.S. Environmental Protection Agency . USEPA. 1999. Evaluation of Chemical Manufacturers Associatio n Antimicrobial Exposure Assessment Study (Amended on 8 December 1992). Memorandum from Siroos Mostaghimi, PH.D., USEPA to Julie Fairfax, USEPA. Dated November, 4 1999. DP Barcode D247642. USEPA. 2000. Residential SOPs. EPA Office of Pesticide Programs, Human Health Effects Division. Dated April 5, 2000. USEPA. 2001. HED Science Advisory Council for Exposure. Policy Update, November 12. Recommended Revisions to the Standard Operating Procedures (SOPs) for Residential Exposure Assessment, February 22, 2001.Page 37 of 43 

### APPENDIX A: Summary of CMA and PHED DataPage 38 of 43



### Chemical Manufacturers Association (CMA) Data: In response to an EPA Data Call
- In Notice, a study was undertaken by the Institute of A gricultural Medicine and Occupational Health of The University of I owa under contract to the Chemical Manufacturers Association. In order to meet the requirements of Subdivision U of the Pesticide Assessment Guidelines (superseded by Series 875.1000
- 875.1 600 of the Pesticide Assessment Guidelines), handler exposure data are required from the chemical manufacturer specifically registering the antimicrobial pesticide. The applicator exposure study must comply with the assessment guidelines for Applicator Exposure Monitoring in Subdivision U and the Occupational and Residential Exposure Test Guidelines in Series 875. For this purpose, CMA submitted a study on 28 February, 1990, entitled "Antimicrobial Exposure Assessment Study (amended on December 8, 1992)" which was conducted by William Popendorf, et al. It was evaluated and accepted by Occupational and Residential Exposure Branch (OREB) of Health Effect Division (HED), Office of Pesticides Program (OPP) of EPA in 1990. The purpose of this CMA study was t o characterize exposure to antimicrobial chemicals in order to support pesticide reregistrations (CMA, 1992). The unit exposure value s presented in the most recent EPA evaluation of the CMA database (USEPA, 1999b) were used in this assessment. The advant ages of CMA data over other surrogate data sets is that the chemicals and the job functions of mixer/loader/applicator were defined based on common application methods used for antimicrobial pesticides. A few of the deficiencies in the CMA data are noted below:

· The inhalation concentrations were ty pically below the detection limits, so the unit exposure value s for the inhalation exposure route could not be accurately calculated. · QA/QC problems in the study includ ed a lack of or low recovery of either/or field fortification, laboratory recoveries, and storage stability information. · Data have an insufficient amount of replicates. The Pesticide Handlers Exposure Database (PHED): The Pesticide Handlers Exposure Database (PHED) has been developed by a Task Fo rce consisting of representatives from Health Canada, the U.S. Environmental Protection Agency (EPA), and the American Crop Protection Association (ACPA). PHED provides generic pesticide worker (i.e., mixer/loader and applicator) exposure estimates. The dermal and inhalation exposure estimates generated by PHED are based on actual field monitoring data, which are reported generically (i.e., chemical specific names not reported) in PHED. It has been the Agency ’ s policy to use surrogate or generic exposure data for pesticide applicators in certain circumstances because it is believed that the physical parameters (e.g., packaging ty pe) or application technique (e.g., aerosol can), not the chemical properties of the pesticide, attribute to exposure levels. [N ote: Vapor pressures for the chemicals in PHED are in the range of E
- 5 to E - 7 mm Hg.] Chemical specific properties are accounted for by correcting the exposure data for study specific field and laboratory recovery values as specified by the PHED grading c riteria. PHED handler exposure data are generally provided on a normalized basis for use in exposure assessments. The most common method for normalizing exposure is by pounds of activePage 39 of 43



### ingredient (ai) handled per replicate (i.e., exposure in mg per repli cate is divided by the amount of ai handled in that particular replicate). These unit exposures are expressed as mg/lb ai handled. This normalization method presumes that dermal and inhalation exposures are linear based on the amount of active ingredient handled.Page 40 of 43 

### Appendix B MCCEM Output Air Concentration Estimates for Fogging Poultry HousesPage 41 of 43

Time (days) Time

(hour) Conc Outdoors

(mg/m3) Conc Zone 1 (mg/m3) Conc@Person(mg/m3) 0 0 0 20.61 0 0.00694444 0.1666666 1.12E - 55 10.5816 10.5816 0.0138889 0.3333336 1.70E - 55 5.43277 5.43277 0.0208333 0.4999992 2.00E - 55 2.78928 2.78928 0.0277778 0.6666672 2.15E - 55 1.43207 1.43207 0.0347222 0.8333328 2.23E - 55 0.735252 0.735252 0.0416666 0.9999984 2.27E - 55 0.377492 0.377492 0.0486111 1.1666664 2 .29E - 55 0.193811 0.193811 0.0555555 1.333332 2.30E - 55 0.0995064 0.0995064 0.0625 1.5 2.31E - 55 0.0510884 0.0510884 0.0694444 1.6666656 2.31E - 55 0.0262297 0.0262297 0.0763888 1.8333312 2.31E - 55 0.0134668 0.0134668 0.0833333 1.9999992 2.31E - 55 0.00691413 0.00691413 0.0902777 2.1666648 2.31E - 55 0.00354984 0.00354984 0.0972222 2.3333328 2.31E - 55 0.00182255 0.00182255 0.104167 2.500008 2.31E - 55 0.000935733 0.000935733 0.111111 2.666664 2.31E - 55 0.000480423 0.000480423 0.118055 2.83332 2.31E - 55 0.0002466 58 0.000246658 0.125 3 2.31E - 55 0.000126639 0.000126639 0.131944 3.166656 2.31E - 55 6.50E - 05 6.50E - 05 0.138889 3.333336 2.31E - 55 3.34E - 05 3.34E - 05 0.145833 3.499992 2.31E - 55 1.71E - 05 1.71E - 05 0.152778 3.666672 2.31E - 55 8.80E - 06 8.80E - 06 0.159722 3.833 328 2.31E - 55 4.52E - 06 4.52E - 06 0.166667 4.000008 2.31E - 55 2.32E - 06 2.32E - 06 0.173611 4.166664 2.31E - 55 1.19E - 06 1.19E - 06 0.180555 4.33332 2.31E - 55 6.11E - 07 6.11E - 07 0.1875 4.5 2.31E - 55 3.14E - 07 3.14E - 07 0.194444 4.666656 2.31E - 55 1.61E - 07 1.61E - 07 0. 201389 4.833336 2.31E - 55 8.27E - 08 8.27E - 08 0.208333 4.999992 2.31E - 55 4.25E - 08 4.25E - 08 0.215278 5.166672 2.31E - 55 2.18E - 08 2.18E - 08 0.222222 5.333328 2.31E - 55 1.12E - 08 1.12E - 08 0.229167 5.500008 2.31E - 55 5.75E - 09 5.75E - 09 0.236111 5.666664 2.31E - 55 2 .95E - 09 2.95E - 09 0.243055 5.83332 2.31E - 55 1.52E - 09 1.52E - 09 0.25 6 2.31E - 55 7.78E - 10 7.78E - 10 0.256944 6.166656 2.31E - 55 4.00E - 10 4.00E - 10 0.263889 6.333336 2.31E - 55 2.05E - 10 2.05E - 10 0.270833 6.499992 2.31E - 55 1.05E - 10 1.05E - 10 0.277778 6.666672 2. 31E - 55 5.41E - 11 5.41E - 11 0.284722 6.833328 2.31E - 55 2.78E - 11 2.78E - 11 0.291666 6.999984 2.31E - 55 1.43E - 11 1.43E - 11 0.298611 7.166664 2.31E - 55 7.32E - 12 7.32E - 12 0.305555 7.33332 2.31E - 55 3.76E - 12 3.76E - 12 0.3125 7.5 2.31E - 55 1.93E - 12 1.93E - 12Page 42 of 43

0.319444 7.666656 2.31E - 55 9.90E - 13 9.90E - 13 0.326389 7.833336 2.31E - 55 5.08E - 13 5.08E - 13 0.333333 7.999992 2.31E - 55 2.61E - 13 2.61E - 13 0.340278 8.166672 2.31E - 55 1.34E - 13 1.34E - 13 0.347222 8.333328 2.31E - 55 6.88E - 14 6.88E - 14 0.354166 8.499984 2.31E - 55 3.53E - 1 4 3.53E - 14 0.361111 8.666664 2.31E - 55 1.81E - 14 1.81E - 14 0.368055 8.83332 2.31E - 55 9.31E - 15 9.31E - 15 0.375 9 2.31E - 55 4.78E - 15 4.78E - 15 0.381944 9.166656 2.31E - 55 2.45E - 15 2.45E - 15 0.388889 9.333336 2.31E - 55 1.26E - 15 1.26E - 15 0.395833 9.499992 2.31E - 5 5 6.47E - 16 6.47E - 16 0.402778 9.666672 2.31E - 55 3.32E - 16 3.32E - 16 0.409722 9.833328 2.31E - 55 1.71E - 16 1.71E - 16 0.416666 9.999984 2.31E - 55 8.76E - 17 8.76E - 17 0.423611 10.166664 2.31E - 55 4.50E - 17 4.50E - 17 0.430555 10.33332 2.31E - 55 2.31E - 17 2.31E - 17 0.43 75 10.5 2.31E - 55 1.19E - 17 1.19E - 17 0.444444 10.666656 2.31E - 55 6.09E - 18 6.09E - 18 0.451389 10.833336 2.31E - 55 3.12E - 18 3.12E - 18 0.458333 10.999992 2.31E - 55 1.60E - 18 1.60E - 18 0.465277 11.166648 2.31E - 55 8.24E - 19 8.24E - 19 0.472222 11.333328 2.31E - 55 4.23 E - 19 4.23E - 19 0.479166 11.499984 2.31E - 55 2.17E - 19 2.17E - 19 0.486111 11.666664 2.31E - 55 1.11E - 19 1.11E - 19 0.493055 11.83332 2.31E - 55 5.72E - 20 5.72E - 20 0.5 12 2.31E - 55 2.94E - 20 2.94E - 20