UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, DC 20460

			OFFICE OF  PREVENTION, PESTICIDES,  AND TOXIC SUBSTANCES

 

September 17, 2007

MEMORANDUM:

Subject:		Revised Occupational and Residential Exposure Chapter for
Octhilinone (OIT) for the Reregistration Eligibility Decision (RED)
Document (Case 2475)

To:			K. Avivah Jacob, Chemical Review Manager,

			Regulatory Management Branch II

Antimicrobials Division (7510P)

From: 			Cassi Walls, Ph.D., Chemist

Risk Assessment and Science Support Branch (RASSB)

Antimicrobials Division (7510P)

Thru:			Norm Cook, Branch Chief

Risk Assessment and Science Support Branch (RASSB)

Antimicrobials Division (7510P)

DP Barcode: 		

Chemical Name:	2-n-Octyl-4-isothiazolin-3-one (Octhilinone or OIT)	

		

PC Code:		099901 

CAS Registry No. 	26530-20-1TABLE OF CONTENTS

  TOC \h \l "1-4"   HYPERLINK \l "_Toc159733450"  EXECUTIVE SUMMARY	 
PAGEREF _Toc159733450 \h  2  

  HYPERLINK \l "_Toc159733451"  1.0	INTRODUCTION	  PAGEREF _Toc159733451
\h  6  

  HYPERLINK \l "_Toc159733452"  1.1	Purpose	  PAGEREF _Toc159733452 \h 
6  

  HYPERLINK \l "_Toc159733453"  1.2	Criteria for Conducting Exposure
Assessments	  PAGEREF _Toc159733453 \h  6  

  HYPERLINK \l "_Toc159733454"  1.3	Chemical Identification	  PAGEREF
_Toc159733454 \h  8  

  HYPERLINK \l "_Toc159733455"  1.4	Physical/Chemical Properties	 
PAGEREF _Toc159733455 \h  8  

  HYPERLINK \l "_Toc159733456"  2.0	USE INFORMATION	  PAGEREF
_Toc159733456 \h  8  

  HYPERLINK \l "_Toc159733457"  2.1	 Formulation Types and Percent
Active Ingredient	  PAGEREF _Toc159733457 \h  8  

  HYPERLINK \l "_Toc159733458"  2.2	Summary of Use Pattern and
Formulations	  PAGEREF _Toc159733458 \h  8  

  HYPERLINK \l "_Toc159733459"  3.0	SUMMARY OF TOXICITY CONCERNS
RELATING TO EXPOSURE	  PAGEREF _Toc159733459 \h  10  

  HYPERLINK \l "_Toc159733460"  3.1	Acute Toxicity	10 

  HYPERLINK \l "_Toc159733461"  3.2	Summary of Toxicity Endpoints	 
PAGEREF _Toc159733461 \h  10  

  HYPERLINK \l "_Toc159733463"  4.0	RESIDENTIAL EXPOSURE ASSESSMENT	 
PAGEREF _Toc159733463 \h  12  

  HYPERLINK \l "_Toc159733464"  4.1	Summary of Registered Uses	  PAGEREF
_Toc159733464 \h  12  

  HYPERLINK \l "_Toc159733465"  4.2	Dietary Exposure/Risk Pathway	12 

  HYPERLINK \l "_Toc159733466"  4.3	Drinking Water Exposure/Risk Pathway
  PAGEREF _Toc159733466 \h  13  

  HYPERLINK \l "_Toc159733467"  4.4	Residential Exposures	  PAGEREF
_Toc159733467 \h  13  

  HYPERLINK \l "_Toc159733468"  4.4.1	Residential Handler Exposures	 
PAGEREF _Toc159733468 \h  13  

  HYPERLINK \l "_Toc159733469"  4.4.2	Residential Post-application
Exposures	  PAGEREF _Toc159733469 \h  17  

  HYPERLINK \l "_Toc159733470"  4.4.2.1	Treated Carpet	  PAGEREF
_Toc159733470 \h  17  

  HYPERLINK \l "_Toc159733471"  4.4.2.2	Treated Vinyl	21 

  HYPERLINK \l "_Toc159733472"  4.4.2.3	Textiles (Clothing)	  PAGEREF
_Toc159733472 \h  25  

  HYPERLINK \l "_Toc159733473"  4.4.2.4	Mattresses	27 

  HYPERLINK \l "_Toc159733474"  4.4.2.5	Plastics	  PAGEREF _Toc159733474
\h  29  

  HYPERLINK \l "_Toc159733475"  4.4.3	Data Limitations/Uncertainties	31 

  HYPERLINK \l "_Toc159733476"  5.0	RESIDENTIAL AGGREGATE RISK
ASSESSMENTS AND RISK CHARACTERIZATION	32 

  HYPERLINK \l "_Toc159733477"  6.0	OCCUPATIONAL EXPOSURE AND RISK	 
PAGEREF _Toc159733477 \h  34  

  HYPERLINK \l "_Toc159733478"  6.1	Summary of Registered Uses	  PAGEREF
_Toc159733478 \h  34  

  HYPERLINK \l "_Toc159733479"  6.2	Occupational Handler Exposures	37 

  HYPERLINK \l "_Toc159733480"  6.3	Occupational Post-application
Exposures	41 

  HYPERLINK \l "_Toc159733481"  6.4	Metalworking Fluids:  Machinist	41 

  HYPERLINK \l "_Toc159733482"  6.5	Professional Painter	44 

  HYPERLINK \l "_Toc159733482"  6.5.1	Professional Painter - Short-term
Dermal Exposure (Irritation)	44 

  HYPERLINK \l "_Toc159733482"  6.5.2	Professional Painter – Airless
Sprayer Inhalation Exposure	44 

  HYPERLINK \l "_Toc159733483"  6.6	Leather Processing	46 

  HYPERLINK \l "_Toc159733485"  6.7	Data Limitations/Uncertainties	48 

  HYPERLINK \l "_Toc159733486"  7.0	REFERENCES	48 

 

EXECUTIVE SUMMARY tc \l1 "EXECUTIVE SUMMARY 

		The Antimicrobials Division (AD) prepared this revised occupational
and residential exposure chapter for the inclusion in the Octhilinone
(OIT) Reregistration Eligibility Decision (RED) Document.  It addresses
the potential risks to humans that result from the use of this chemical
in occupational and residential settings. The initial assessment was
updated to incorporate error only and public comments received during
previous Phases of the RED process.  

Currently, OIT is an active ingredient used for materials preservation
(Use Site Category VII), wood preservation (Use Site Category X), and
water systems biocide treatments (Use Site Category VIII).  Examples of
the materials preserved using OIT include carpeting, vinyl, leather,
textiles, mattresses, metalworking fluids, plastics, polymers, and
coatings (e.g., stains, paints).  The percentage of OIT in various
end-use products can range from 1.29% to 46.5%.  Products containing OIT
are formulated as liquid concentrates.

The routes and duration of exposure evaluated in this assessment
include: short-term (ST) (1-30 days) and intermediate-term (IT) (1 - 6
months) dermal, inhalation, and incidental oral exposures.  The NOAEL is
5 mg/kg/day for ST and IT incidental oral exposure, 0.0674 mg/cm2 for ST
dermal exposure leading to irritation, 5.95 mg/kg/day for IT dermal
exposure leading to systemic effects, and 0.073 mg/m3 for ST and IT
inhalation exposure.  The target margin of exposure (MOE) varies by
route and duration of exposure.  For OIT, the target MOE is 100 for ST
incidental oral and IT dermal exposures; 30 for ST and IT inhalation
exposures; 300 for IT incidental oral exposure; and 10 for ST dermal
exposures leading to irritation.   

	Based on examination of product labels describing uses for this
antimicrobial, it has been determined that exposure to handlers can
occur in a variety of occupational and residential environments. 
Additionally, post-application exposures are likely to occur in these
settings.  The representative scenarios selected by AD were evaluated
using maximum application rates as stated on the product labels. To
assess the handler and post-application exposures and risks, AD used
standard assumptions, surrogate unit exposure data (from the Chemical
Manufacturers Association (CMA) antimicrobial exposure study, the
Pesticide Handlers Exposure Database (PHED), 2005 Human and
Environmental Risk Assessment on Ingredients of Household Cleaning
Products (HERA), and EPA’s Health Effects Division’s (HED) Standard
Operating Procedures (SOPs) for Residential Exposure Assessments.

Handler Risk Summary

		For the residential handler exposure assessment, the ST dermal and
inhalation MOE resulting from application of paint using a brush/roller
results in MOEs above 10 and 30, respectively.  The other residential
painter ST inhalation exposures were below the target MOE of 30, as
follows:

ST inhalation exposures resulting from the application of paint using an
airless sprayer:  MOE = 1 - 6.

		

For the occupational handler dermal and inhalation risk assessment, the
MOEs were above target MOEs of 100 (IT dermal), 10 (ST dermal), and 30
(ST/IT inhalation), for all scenarios except the following:

IT dermal exposure resulting from liquid pour for preservation of
plastics and vinyl:  MOE = 39.

ST/IT inhalation exposures resulting from liquid pour for preservation
of plastics and vinyl:  MOE = 2.

IT dermal exposure resulting from liquid pump for preservation of
plastics and vinyl:  MOE = 83.

ST/IT inhalation exposures resulting from liquid pump for preservation
of plastics and vinyl:  MOE = 2.

IT dermal exposure resulting from liquid pour for preservation of paint:
 MOE = 67.

ST/IT inhalation exposures resulting from liquid pour for preservation
of paint:  MOE = 4.

ST/IT inhalation exposures resulting from liquid pump for preservation
of paint:  MOE = 3.

ST/IT inhalation exposures resulting from liquid pour for preservation
of textiles:  MOE = 14.

ST/IT inhalation exposure resulting from applying paint via
brush/roller:  MOE = 25.

ST/IT inhalation exposures resulting from the application of paint using
an airless sprayer:  MOE = 1 - 2.

	It should be noted that in most cases the short-term dermal exposures
were not assessed for the occupational handler because the endpoint is
based on dermal irritation.  Instead, dermal irritation exposures and
risks will be mitigated using default personal protective equipment
requirements based on the toxicity of the end-use product.  To minimize
dermal exposures, the minimum PPE required for mixers, loaders, and
others exposed to end-use products that result in classification of
category I, II, or III for skin irritation potential will be a
long-sleeve shirt, long pants, shoes, socks, chemical-resistant gloves,
and a chemical-resistant apron.  Once diluted, if the concentration in
the diluted solution will result in classification of toxicity category
IV for skin irritation potential, then the chemical-resistant gloves and
chemical-resistant apron can be eliminated for applicators and others
exposed to the dilute product. Note that chemical-resistant eyewear will
be required if the end-use product is classified as category I or II for
eye irritation potential.   In cases where gloves are not a viable
mitigation option (e.g., painters and metal working machinists), ST
dermal exposures were assessed.

Post-application/Bystander Risk Summary

Occupational post-application exposures are assumed to be minimal and
therefore not quantitatively assessed.  For the residential
postapplication risk assessment, MOEs are above the respective target
MOEs (10 for ST dermal exposures, 100 for IT dermal exposures, 100 for
ST incidental ingestion exposures, and 300 for IT incidental ingestion
exposures) for all scenarios except for the following:

ST dermal exposure of children to treated carpet: MOE = 9  

IT dermal exposure of children to treated carpet: MOE = 6

ST incidental ingestion exposure of children to treated carpet: MOE = 6 


IT incidental ingestion exposure of children to treated carpet: MOE = 13

IT dermal exposure of children to treated mattresses: MOE = 73

Aggregate Risk Summary

	For the residential aggregate risk assessments, the MOEs were above
target MOE for all scenarios except the following:

ST incidental oral aggregate exposure of children: MOE = 69 (Target MOE
= 100)

Data Limitations and Uncertainties:

There are a number of uncertainties associated with this assessment,
including the following: 

Surrogate dermal and inhalation unit exposure values were taken from the
proprietary CMA antimicrobial exposure study (US EPA 1999: DP Barcode
D247642) or the Pesticide Handler Exposure Database (US EPA 1998). Most
of the CMA data are of poor quality therefore, AD 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 (US EPA 2000, 2001) and standard AD
assumptions that can be further refined from input from registrants. 

The water system uses are only listed on an MUP label (EPA Reg. No.
707-308) which does not provide application or use rates.  Since there
are no EUP labels containing water system uses, these uses were not
assessed.  The MUP labels need to be updated to delete these uses or new
EUP labels need to be submitted and reviewed by the Agency.  As a follow
up to the September 14, 2006 SMART meeting, the registrant indicated
that the water system use will be removed from the label.

The dermal exposure estimate for both the residential and occupational
painter scenarios using treated paint was based on wet film thickness
data from a study where the user’s hands were immersed twice in
mineral oil; no information specific to the wet film thickness of paint
was identified.  The method employed may result in an underestimate of
dermal exposures to paint.  The assessment could be refined by
conducting a dermal irritation study where OIT treated paint is the test
substance.

For the airless sprayer inhalation exposure scenarios, the aerosol
particle size distribution resulting from the use of an airless sprayer
is largely unknown.  The NPCA study suggested that the respirable
aerosol mass in the breathing zone was no more than 16% of the total
mass measured.  The study did not provide raw data to support this
statement nor did it actually measure the particle sizes.  Therefore, a
study is needed to determine aerosol size distribution that is less than
100 microns.  Without this data, the PHED exposure estimates can not be
corrected for the aerosol size distribution, as suggested by the OIT
Task Force.

There are no available data on the quantity of residue dislodged from
treated leather.  As a result, it was assumed that the residential post
application exposure from textiles is representative of post-application
exposures from leather.  

A confirmatory study is needed to verify the 5% transfer factor for
clothing and mattress covers.

The default residue transfer factors for carpeting (5%) and clothing
(5%) may not be representative of the actual transfer values.  It is
uncertain to what degree the residue is actually being transferred
because OIT is impregnated in the fiber matrix and it is unknown whether
or not the matrix is actually binding the OIT thereby reducing the
potential transfer.

Although AMEM modeling was conducted, it is uncertain to what degree the
residue is actually being transferred throughout the vinyl flooring
matrix.

The textile preserved at the manufacturing facility scenario also
represents the laundered clothing scenario, however the transfer factors
may be different.  The fabrics preserved in the manufacturing facility
may have a lower transfer factor than those laundered due to the matrix
effects.  It would seem reasonable that the residues on the laundered
fabrics are on the surface of the material rather than “impregnated”
thus having a higher dislodgeable potential.  

1.0	 INTRODUCTION tc \l1 "1.0	INTRODUCTION 

		1.1	Purpose  tc \l2 "1.1	Purpose  

		This document presents the results of a review of the potential human
health effects of occupational and residential exposure to octhilinone
(OIT).  This information is for use in EPA’s development of the OIT
Reregistration Eligibility Decision (RED) Document. 

		1.2	Criteria for Conducting Exposure Assessments tc \l2 "1.2	Criteria
for Conducting Exposure Assessments 

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

In this document, 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 (1mg = 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
typically considered in assessments (i.e., there are different unit
exposures for different types of application equipment, 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 U.S. EPA 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 estimates of daily amount handled, exposures and risks to
handlers were assessed.  The exposure/risks were calculated using the
following equations:

Daily Exposure: Daily dermal or inhalation handler exposures are
estimated for each applicable handler task with the application rate,
quantity treated/handled in a day, and the applicable dermal or
inhalation unit exposure using the following formula:

Daily Exposure:	E = UE x AR x AT						(Eq. 1)

Where:  

E	=	Amount (mg a.i./day) deposited on the surface of the skin that is
available for dermal absorption or amount inhaled that is available for
inhalation absorption;

UE	=	Unit 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, square
feet (sq. ft.), gallons (gal), or cubic feet (cu. ft). Maximum values
are generally used (lb a.i./sq ft, lb ai/gal, lb ai/cu ft); and

AT 	=	Normalized application 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 daily dermal or inhalation dose is calculated by
normalizing the daily exposure by body weight and adjusting, if
necessary, with an appropriate absorption factor.  For OIT, a dermal
endpoint was used for evaluation of dermal exposures and an inhalation
endpoint was used for evaluation of inhalation exposures; therefore, an
absorption factor of 100% was used for all exposures.  Daily dose was
calculated using the following formula:

Daily Dose:	ADD = E x ABS							(Eq. 2)

			   BW						

Where:

ADD 	= 	Absorbed dose received from exposure to a chemical in a given
scenario (mg active ingredient/kg body weight/day);

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

ABS 	= 	A measure of the amount of chemical that crosses a biological
boundary such as lungs (% of the total available absorbed); and

BW	= 	Body weight determined to represent the 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), which is a ratio of the daily dose 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 LOAEL	= 	Dose level in a toxicity study, where no observed
adverse effects (NOAEL) or where the lowest observed adverse effects
(LOAEL) occurred in the study; and

ADD 			= 	Average daily dose or the absorbed dose received from exposure
to a chemical in a given scenario (mg ai/kg body weight/day).

	In addition to the target MOEs from 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:

OIT products are registered for various use patterns and use conditions
too numerous to conduct a comprehensive assessment for this document. 
As such, this risk assessment has been patterned on a series of
scenarios that are believed to represent the vast majority of OIT uses.

Average body weights of 70 kg for adults and 15 kg for children were
used as appropriate to complete the non-cancer risk assessment.  

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 tc \l2 "1.3	Chemical Identification 

		The chemical under review is octhilinone (OIT), with a molecular
formula of C11H19NOS.  The Product Code for this chemical is 099901 and
the CAS RN is 26530-20-1.  

		1.4	Physical/Chemical Properties tc \l2 "1.4	Physical/Chemical
Properties 

		Table 1.2 shows physical/chemical characteristics that have been
reported for OIT.

Table 1.2.  Physical/Chemical Properties of OIT



Molecular Weight	

213.34 g/mol



Vapor Pressure	

3.68E-05 mmHg



2.0	 USE INFORMATION tc \l1 "2.0	USE INFORMATION 

		2.1	 Formulation Types and Percent Active Ingredient tc \l2 "2.1	
Formulation Types and Percent Active Ingredient 

		The products containing OIT as the active ingredient (a.i.) are
formulated as soluble concentrates in end-use products.  Concentrations
of OIT in these products range from 1.29% to 46.5%.

		

		2.2	Summary of Use Pattern and Formulations tc \l2 "2.2	Summary of Use
Pattern and Formulations 

	OIT is an industrial microbiocide that is an active ingredient in 31
registered products.  AD determined potential occupational and
residential exposure scenarios by reviewing currently registered labels.
 These scenarios are presented in Table 2.1.  Based on this review of
the labels, it was determined that OIT products are intended for use as
materials preservatives (Use Site Category VII), industrial mildewcides
for cooling tower and air washer water systems (Use Site Category VIII),
and as a wood preservative (Use Site Category X).  Examples of
registered uses for OIT as a materials preservative include metalworking
fluids, coatings, stains and paints, glues and adhesives, building
materials, fabrics, carpet, glazes, paper, leather and leather products,
and polymers (which may include plastic toys). 

Table 2.1. Potential Use Scenarios Based on Product Labels for
Octhilinone



Use Site Category	

Example Use Sites	

Scenarios



Use Site Category VII

Material Preservatives	

Used in the production of various household, institutional and
industrial items	

Addition to products during manufacture, including:

Polymers compounds, including plastic; polyurethane; and PVC flooring,
wall coverings, slippers, gloves, tiles, and fibers

Leather, hides, skins, and artificial leather

Textiles, including treated and laundered fabrics, towels, and linen

Shoes

Gloves

Coated fabrics (wall coverings, upholstery, pillow/mattress ticking,
awnings, tents, tarpaulins, protective covers, awnings, aprons,
automotive landau tops)

Indoor/outdoor carpeting and backing

Foams (pillow/mattress foam, carpet underlay, gaskets, shoe soles)

Feather and down fill

Caulks, sealants, adhesives, fillers, grouts, wallpaper paste, stucco,
and other building materials 

Coatings/sealants (industrial urethane coatings, artificial leather,
sail cloth, rainwear, silicone caulks for bathroom and industrial use,
carpet backing)

Paints, mastics, stains, and coatings

Adhesives and tackifiers 

Polymer, synthetic, and rubber lattices

Garden hoses and cable casings

Air filter media and polyester fiber

Soluble, synthetic, and semi-synthetic metalworking fluids

Soluble oils, high water-based and invert-emulsion hydraulic fluids 

Water based emulsions, including latex and latex coatings

Vinyl film and sheeting (liners for pools, ponds, ditches, and
waterbeds, shower curtains, mats, insulators); 

Plastisols (vinyl flooring, adhesives for industrial coated fabrics,
vinyl, and windows, grout/pipe sealants)

Molded goods (vinyl floor tile, waste containers, shoe soles)

Extruded profiles (automotive moldings, weather stripping, exterior
trim, gaskets, floor moldings); 

Refrigerator gaskets

Interior automotive parts



Use Site Category VIII

Industrial processes and water systems	

Used on fresh water supplies for commercial and industrial systems	

Addition to water for cooling towers

Addition to water for air washers



Use Site Category X

Material Preservatives	

Used in preservation of  wood products	

Application to Pinus radiata logs for plywood

	From Table 2.1, representative exposure scenarios were selected for
assessment in this document.  These scenarios were selected to be
representative of the vast majority of uses and are believed to provide
high-end estimates 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).

3.0	SUMMARY OF TOXICITY DATA tc \l1 "3.0	SUMMARY OF TOXICITY CONCERNS
RELATING TO EXPOSURE 

3.1	Acute Toxicity

 tc \l2 "3.1	Acute Toxicity 

Adequacy of database for Acute Toxicity:  The acute toxicity database
for octhilinone is considered incomplete. The acute toxicity data for
OIT is summarized below in Table 3.1.

Table 3.1 Acute Toxicity Profile Octhilinone

Guideline Number	Study Type/Test substance (% a.i.)	MRID Number/
Classification	Toxicity Category

870.1100	Acute Oral Toxicity (gavage) – Rat (Technical 85-95% a.i.)
MRID 00070456	Toxicity Category III

870.1200	Acute Dermal Toxicity – Rabbit (Technical 85 -95 % a.i.)	MRID
00070456

Acceptable - Guideline	Toxicity Category II

	Acute Inhalation Toxicity – Mouse (Technical 95% a.i.)	MRID 00070456

Not acceptable/ Not Guideline	Toxicity Category III



870.2400	Primary eye irritation – Rabbit (Technical 95% a.i.)	MRID
00070456

Acceptable - Guideline	Toxicity Category I (Corrosive)

870.2500	Primary Skin irritation – Rabbit (50% a.i.)	MRID 00063214

Not acceptable/ Not Guideline	Toxicity Category I (Corrosive)

870.2600	Dermal Sensitization – Guinea Pig	MRID 41482505, 41482507

Not acceptable/ Not Guideline	Sensitizer



	3.2	Summary of Toxicity Endpoints tc \l2 "3.2	Summary of Toxicity
Endpoints 

The interim toxicological endpoints were selected for octhilinone. 
Table 3.2 summarizes the toxicological endpoints for OIT used in the
evaluation of exposures and MOEs.  The reader is referred to the
following memorandum for more details: Memorandum: Evaluation of
Toxicology Database for the Reregistration Eligibility Decision Document
Disciplinary Chapter, From:  Steven M. Malish, Ph.D. and Tim McMahon,
Ph.D., To: K. Avivah Jacob, dated March 5, 2007.

Table 3.2. Summary of Toxicological Dose and Endpoints for Octhilinone
for Use in Risk Assessment



Exposure  Scenario	

Dose (mg/kg/day)

	

   Endpoint	

   Study



Acute Dietary	

Will  not be  used  on food, therefore,  acute RfD not required



Chronic Dietary	

Will  not be  used  on food, therefore, chronic RfD not required 



Occupational /Residential Exposure



1. Incidental Oral 

Short Term;

Intermediate Term

MRID 41482508

	Systemic: 

NOAEL: 5 mg/kg/day

MOE = 100 for Short-term

MOE = 300 for Intermediate Term	Systemic: Mortality, decreased body
weight and body weight gain, decreased food consumption 	Developmental
Study 

Acceptable/Guideline



2. Short-term  (Dermal)

[1 Day to 30 Days]

MRID 43935705

[5 x 7 cm application area]	

Dermal Irritation: 

NOAEL: 0.0674 mg/cm2

(10 mg/kg/day)

MOE = 10+	

Dermal: dermal irritation in both sexes 

Systemic: No systemic effects

	

14 Day Dermal Study

Acceptable/Non-guideline



4. Intermediate-term (Dermal)

[30 Days to 6 Months]

MRID 42007301

[4 x 5 cm application area]	

Systemic: NOAEL: 5.95 mg/kg/day

MOE = 100

	

Systemic: 

Decreases in HGB, HCT, RBC, albumin, and total protein and a decrease in
body weight gain in the male	

90 Day Dermal Study

Acceptable/Guideline



5. Long-term (Dermal)

(>6 Months)	

Not Selected	

Not Selected	

Not Selected



6. Inhalation

(short/intermediate-term

[0 to 30 Days]/[30 Days to 6 Months]

MRID 415447-01	

++

2 hr HEC: 0.29 mg/m3

4 hr HEC: 0.15 mg/m3

6 hr HEC: 0.10 mg/m3

8 hr HEC: 0.073 mg/m3

MOE = 30	

Clinical signs (rales, dyspnea) decreases in body weight gain, and
pulmonary and nasal cavity pathology	

90 Day Inhalation Toxicity

Acceptable-Guideline

+	The use of dermal irritation is applied only for the short short-term
dermal exposure scenario.  A margin of exposure (MOE) of 10 is used for
the short-term assessment (3x inter-species variation, 3x intra-species
variation).  

++	Human Equivalent Concentrations (HECs) were calculated using the
Regional Deposited Dose Ratio (RDDR) for nonhygroscopic particles and
the study NOAEL of 0.64 mg/m3

	Where, HEC = RDDR x NOAEL x (6hr (rats exposure time in study) / hr
(worker exposure time)) 

4.0	RESIDENTIAL EXPOSURE ASSESSMENT tc \l1 "4.0	RESIDENTIAL EXPOSURE
ASSESSMENT  

	4.1	Summary of Registered Uses tc \l2 "4.1	Summary of Registered Uses 

	Although no products containing OIT are labeled for residential uses,
residents may be exposed to household items that have been treated with
OIT through material preservation (e.g., carpet, paints, and plastics). 
Table 2.1 presents a summary of exposure scenarios that may occur from
the residential use site category based on examination of product
labels.  Table 4.1 identifies the representative exposure scenarios
assessed in this document.

Table 4.1. Representative Uses Associated with Residential Exposure 



Representative Use	

Exposure Scenario	

Application Method	

Registration #	

Application Rate

Using treated paints	ST handler: dermal (irritation) and inhalation
(aerosol) 	brush/ roller

airless sprayer	67071-31

	0.23% a.i. by weight (16.84% a.i. x 13.8 lb product/1000 lb paint)

Using treated carpet	ST and IT post-app: child incidental ingestion and
dermal	NA	67071-6	0.12% a.i. by weight (0.25% product by weight of
material x 46.5% a.i. in product) 

Using treated vinyl floor	ST and IT post-app: child incidental ingestion
and dermal	NA	67071-43	0.37% a.i. by weight (4% product by weight of
material x 9.3% a.i. in product)

Using treated textiles (e.g., clothing and linen) a 	ST post-app: child
incidental ingestion and dermal	NA

	67071-6	0.12% a.i. by weight (0.25% product by weight of material x
46.5% a.i. in product)

Using treated mattresses	ST and IT post-app: child dermal	NA	81348-8
0.4% a.i. by weight (2% product by weight of material x 20% a.i. in
product)

Using treated plastic/polymer products	ST post-app: infant/child
incidental ingestion	NA	81348-8	0.4% a.i. by weight (2% product by
weight of material x 20% a.i. in product)

a Exposure to OIT as a preservative for fabrics/textiles is assumed to
also represent exposure to leather processed using OIT preserved
products

	

	4.2	Dietary Exposure tc \l2 "4.2	Dietary Exposure/Risk Pathway  

Any risks pertinent to dietary exposures are discussed in the
Preliminary Risk Assessment.

	4.3	Drinking Water Exposure tc \l2 "4.3	Drinking Water Exposure/Risk
Pathway  

Any risks pertinent to drinking water exposures are discussed in the
Preliminary Risk Assessment. 

	4.4	Residential Exposures tc \l2 "4.4	Residential Exposures 

	4.4.1	Residential Handler Exposures tc \l3 "4.4.1	Residential Handler
Exposures 

	The types of products treated with OIT that are handled in a
residential setting are treated paints, mastics, stains, building
materials, and similar products as described in Table 4.1.  The
short-term inhalation and dermal residential painter exposures were
assessed and are considered to be representative of all other
residential handler exposures.  Only short-term exposure durations (1 to
30 days) were estimated because it was assumed that a homeowner or
do-it-yourself painter would typically paint on an intermittent basis
(i.e., a few times per year).

Inhalation Exposures

	Residential handlers using preserved paint may have inhalation
exposures to both aerosols and vapors.  In the case of OIT, the vapor
pressure is relatively low therefore the vapor phase was not necessary
to evaluate.  Only inhalation exposure to paint aerosols was
quantitatively assessed.

Exposure Calculation Assumptions

Unit Exposure Values:  Do-it-yourself painters have several techniques
for paint application including paint brush, roller, and airless
sprayer.  There are no chemical-specific exposure data to assess these
techniques however surrogate data are available for painting with a
brush and an airless sprayer.  The surrogate data are based on PHED and
NCPA data for painters wearing no respiratory protection.

For the brush/roller scenario, the PHED inhalation unit exposure value
for a residential handler applying a pesticide using a paint brush was
used.  The test subjects were painting a bathroom with a paint brush. 
This unit exposure value (0.28 mg/lb a.i.) represents a handler wearing
no respiratory protection.

For the airless sprayer scenario, the PHED inhalation unit exposure
value for a residential handler applying a pesticide using an airless
sprayer was used.  The test subjects were staining the outside of a
house with an airless sprayer.  Although these exposures may differ
slightly from exposures of painters of OIT persevered products, these
data are judged to be adequately representative.  The inhalation unit
exposure value for the airless sprayer application was available in
terms of an air concentration (mg/m3/% a.i.) as well as, in terms of
amount handled (mg/lb a.i.).  Since the inhalation toxicity endpoint was
determined from an inhalation study (as opposed to an oral study), the
endpoint units are given in terms of an air concentration (mg/m3). 
Therefore, in order to estimate inhalation risks (MOEs), it was
appropriate to use the unit exposure value in terms of an air
concentration (mg/m3/% a.i.) rather than amount handled (mg/lb a.i.). 
The inhalation unit exposure value of 0.68 mg/m3/% a.i was used for
baseline (i.e., no respirator) exposures.

For the airless sprayer scenario, the OIT Task Force provided an
additional exposure study to supplement the existing PHED data.  The
purpose of this study, conducted by the National Paints and Coatings
Association (NPCA) (Reinhardt and Fendick, 2000), was to estimate
exposure to crystalline silica while spray painting or sanding three
different formulations of latex paint in an indoor environment. Although
the study was conducted to specifically evaluate crystalline silica
exposure, respirable aerosol paint concentrations were measured during
airless spraying activities.  Each of the three paint formulations was
applied by a professional painter on three consecutive days resulting in
nine samples of respirable aerosol paint concentrations.  The test
worker painted the walls and ceilings of rooms measuring 8 feet high, 10
feet wide, and 12 feet long.  A daily painting exposure test (i.e., 8
hour work day) required painting five to eight standard rooms while each
room took 17 – 34 minutes to complete.  The results showed that the
average respirable aerosol breathing zone concentration during airless
spraying of paint was 3.67 mg/m3. The NPCA study suggested that the
respirable aerosol mass in the breathing zone was no more than 16% of
the total mass measured.  Therefore, because the endpoint was based on
nasal irritation, the respirable aerosol paint concentration of 3.67
mg/m3 was adjusted up by 16% to estimate the inhalable aerosol paint
concentration (i.e., air concentration up to 100 microns) of 22.91
mg/m3.  These data were used to further characterize the airless sprayer
inhalation exposure even though the following were identified as
uncertainties or limitations in the NCPA study:

The study did not provide raw data to support the statement that the
respirable aerosol mass in the breathing zone was no more than 16% of
the total mass measured; 

The particle sizes were not actually measured;

No cut point was provided for the size of respirable or inhalable
aerosols.

Based on these limitations, an additional study is needed to determine
aerosol size distribution that is less than 100 microns.  Furthermore,
there is insufficient information on the distribution on the aerosol
size/diameter from the PHED data using the 2L/min sampling pump with
sampling cassettes facing downwards to adjust total aerosols to
inhalable particle size (i.e., 100 microns). Without this data, the air
concentration estimates using the PHED data can not be adjusted down to
estimate only inhalable aerosol concentrations, as suggested by the OIT
Task Force.

Quantity handled/treated: The quantities handled/treated were estimated
based on information from various sources and assumptions. 

For the brush/roller in paint applications, it is assumed that 20 lbs
(approximately 2 gallons) of treated paint will be used.  This is based
on the 90th percentile value of 8 gallons of latex paint used per year
divided by the mean frequency of 4 painting events/year.  	

Exposure time:  It was assumed that it could take residential
applicators 2, 4, or 6 hours to apply paint using a brush/roller or an
airless sprayer.   

Results

	Tables 4.2.1 and 4.2.2 present the calculations of the inhalation doses
and MOEs for a residential painter working with treated paint.  The
short-term inhalation MOEs estimated for use of a brush/roller is above
the target MOE of 30 and not a concern.  However, the short-term
inhalation MOEs estimated while using an airless sprayer are below the
target MOE of 30 and therefore a concern.

Table 4.2.1.  Short-term Inhalation Exposure and MOE for Residential
Painter Using a Brush or Roller

Method of Application	Inhalation Unit Exposure

(mg/lb a.i.)	App. Rate

(% ai)	Quantity Handled 

(lb/day)	Daily Dose (mg/kg/day) a	Air Conc.

(mg/m3)b	HEC

(mg/m3)	MOE (ST) c

Brush/roller	  SEQ CHAPTER \h \r 1 0.28	0.23% 	20 lbs 

(2 gal)	0.00018	0.0016	0.29 at 2 hrs	180

	  SEQ CHAPTER \h \r 1 0.28	0.23% 	20 lbs 

(2 gal)	0.00018	0.0016	0.15 at 4 hrs	90

	  SEQ CHAPTER \h \r 1 0.28	0.23% 	20 lbs 

(2 gal)	0.00018	0.0016	0.10 at 6 hrs	60

a	Inhalation Daily Dose (mg/kg/day) = inhalation unit exposure (mg/lb
a.i.) x application rate x quantity handled / body weight (70 kg).

b	Air conc.(mg/m3) = Dose (mg/kg/day) x BW (70 kg) x Light activity
inhalation rate (day/8m3)

c 	Inhalation MOE = HEC (mg/m3) / Air conc. (mg/m3).  Target inhalation
MOE is 30.

Table 4.2.2.  Short-term Inhalation Exposures and MOEs for Residential
Painter Using an Airless Sprayer

Method of Application	App.Rate 

(% a.i.)	Inhalation Unit Exposure

PHED (mg/m3/%ai) 

NPCA (mg/m3)	Air Conc.

(mg/m3)a	HEC

(mg/m3)	Route Specific 

MOE (ST) b

Airless Sprayer

(PHED)	0.23% 	  SEQ CHAPTER \h \r 1 0.681	0.16	0.29 at 2 hrs	2

	0.23% 	  SEQ CHAPTER \h \r 1 0.681	0.16	0.15 at 4 hrs	1

	0.23% 	  SEQ CHAPTER \h \r 1 0.681	0.16	0.10 at 6 hrs	1

Airless Sprayer

(NPCA)	0.23% 	22.91	0.0053	0.29 at 2 hrs	6

	0.23% 	22.91	0.0053	0.15 at 4 hrs	3

	0.23% 	22.91	0.0053	0.10 at 6 hrs	2

a Air conc (mg/m3) = App Rate (%ai) x PHED UE (mg/m3/%ai)  

(Note that the %ai incorporated the PHED UE is in terms of whole
numbers, not fraction (i.e., 0.23 not 0.0023), therefore the App rate is
used as a whole number in the Air conc. estimate)

Air conc (mg/m3) = App Rate (%ai) x NPCA UE (mg/m3)  

(Note that the App rate is used as a weight fraction in the Air conc.
estimate (i.e., 0.0023))

b Inhalation MOE = HEC (mg/m3) / Air conc. (mg/m3).  Target inhalation
MOE is 30.

Dermal Exposures

Exposure Calculation Assumptions

	As presented in Table 3.2, dermal irritation is a relevant
toxicological endpoint for short-term exposures.  This scenario was
based on EPA’s ChemSteer Model’s two hand immersion method which is
used for the metal working fluid exposure scenario.  Because the ST
dermal endpoint is based on irritation and not systemic effects, the
exposure equation was modified in order to estimate exposure in terms of
a surface area (mg/cm2) rather than a dose (mg/kg/day).    

	Short-term dermal exposures for do-it-yourself painters were assumed to
pose potential risks due to dermal irritation.  Short-term exposure
estimates based on surface area were derived using the following
equation: 

	PE = % ai x FT x PME	         			

where: 

PE		=	Potential exposure (mg/cm2)

% ai	=	Fraction active ingredient in treated paint (unitless)

FT		=	Film thickness of paint on hands (mg/cm2)

PME	=	Paint Matrix Effect (%)

Assumptions

The percent active ingredient was calculated using information from the
label that results in the maximum exposure to OIT (EPA Reg. No.
67071-31, with 16.84% a.i.).  Application rate of this product is 5.5 -
13.8 lb product/1000 lb paint.  Therefore, 

	(% a.i. in paint) 	=	(% a.i. in product) x (application rate)

		=	(16.84% a.i.) x (13.8 lb product/1000 lb paint)

		=	0.23% a.i.

For short-term dermal irritation effects, the film thickness of the
paint on the hands was assumed to be 10.3 mg/cm2.  This film thickness
value is based on a measurement where a worker completely immersed both
hands into mineral oil and allowed no wiping (US EPA 1992). Using this
film thickness may result in an underestimate of exposure because the
actual film thickness of paint is potentially higher than the film
thickness of mineral oil.  A more accurate assessment would require a
dermal irritation study using paint as the test substance.

The “paint matrix effect” parameter pertains to the observation that
OIT is essentially “bound” within the paint matrix thereby reducing
the potential dermal exposure. The OIT Task Force submitted a study that
evaluated the amount of OIT that was available on the skin for exposure
when used in a paint matrix (DiDonato and Hazelton, 1990).  The
percentages of radio-labeled OIT formulated in solvent systems (ethanol
and acetone) and paints (a water-based paint and a solvent-based stain)
remaining on guinea pig skin were compared after 3 hours of exposure. 
The 3 hour duration was selected as the worst case to ensure that the
paint would be wet (a dry film would further bind the OIT to the paint).
The results of the study are summarized below:  

ethanol (500 ppm OIT); unoccluded: 29% availability on skin

acetone (100 ppm OIT); occluded: 36% availability on skin

acetone (500 ppm OIT); occluded: 30% availability on skin

acetone (2000 ppm OIT); occluded: 30% availability on skin

paint 1(1000 ppm OIT); occluded: 7 and 8% availability on skin

paint 2 (1000 ppm OIT); occluded: 5 and 6% availability on skin

stain 1 (5000 ppm OIT); occluded: 5% availability on skin

stain 2(1000 ppm OIT); occluded: 4% availability on skin

By taking into account the ratios of the amount of OIT from paint to the
amount of OIT from the solvent (i.e., 4/36 to 8/29), it appears that OIT
is available for dermal exposure in the range of 11% – 28% when
formulated in the paint matrix as compared to a solvent.  Based on these
results, 28% was used for the paint matrix effect parameter. 

Results

	Table 4.3 shows the calculation of the dermal exposure and MOE for a
residential painter applying treated paint.  Since the calculated MOE of
10 is not below the target MOE of 10, there is no concern for this
scenario.

Table 4.3.  Short-term Dermal Exposures and MOEs for Residential Painter

Exposure Scenario	% ai	Film thickness (mg/cm2)	Paint Matrix Effect (%)
Exposure (mg/cm2)	Dermal MOE 

(Target MOE is 10) a

Painter	0.23%	10.3	28%	0.0067	10

a 	MOE = NOAEL  (mg/cm2) / Potential exposure (mg/cm2) [Where: NOAEL for
short-term dermal irritation = 0.0674 mg/cm2, Table 3.2]. 

	4.4.2	Residential Post-application Exposures tc \l3 "4.4.2	Residential
Post-application Exposures 

	For the purposes of this screening level assessment, postapplication
scenarios have been developed that encompass multiple products, but
still represent high end exposure scenarios for all products
represented. As shown in Table 4.1, representative postapplication
scenarios assessed include contacting treated carpets and vinyl floors
(dermal and incidental oral exposure to children), wearing treated
clothing (dermal exposure to children), using treated mattresses (dermal
exposure to children), mouthing treated textiles such as clothing and
blankets (incidental oral exposure to children), and mouthing treated
plastic toys (incidental oral exposure to infants).  It should be noted
that because OIT has a relatively low vapor pressure, post application
inhalation exposures were not assessed.

	4.4.2.1 Treated Carpet

	Carpet fibers can be treated with OIT during the manufacturing process.
 Therefore post application dermal and incidental oral exposures to
treated carpet fibers may occur.  Since the carpet fibers are actually
impregnated with OIT and the carpeting can be used in a residential
setting there is potential for exposure to occur everyday, assuming that
OIT has a relatively long half life in indoor environments.  Therefore
both short- and intermediate-term exposures durations were assessed.  tc
\l4 "4.4.2.1	Treated Carpet 

Child Dermal Exposure from Treated Carpet

Exposure Calculations

	Short-term exposures - There is the potential for short-term dermal
exposures leading to dermal irritation when children come into contact
with carpeting treated with OIT. Potential exposures and MOEs were
calculated for children contacting treated carpet in residential homes
(short-term exposure).  To determine child short-term exposure to OIT in
carpeting, the following equation was used:

 

where:

PE 	= 	Potential exposure (mg/cm2)

D 	= 	Carpet weight density (oz/yd2)

CF1 	= 	Conversion factor (1.196E-4 yd2/cm2)

WF1 	= 	Weight fraction of commercial product in carpet (oz. product/oz.
carpet)

WF2  	= 	Weight fraction of OIT in commercial product (% a.i.)

WF3 	= 	Weight fraction of OIT transferred from carpet to skin
(unitless)

CF2 	= 	Conversion factor (28,350 mg/oz)

	Intermediate-term exposures - There is also the potential for
intermediate-term dermal exposures leading to systemic effects when
children come into contact with carpeting treated with OIT.  Exposures
and MOEs were calculated for children contacting treated carpet in
residential homes.  To determine child intermediate-term exposure to OIT
in carpeting, the following equation was used:

 

where:

PDD 	= 	Potential daily dose (mg/kg/day)

D 	= 	Carpet weight density (oz/yd2)

CF1 	= 	Conversion factor (1.196x10-4 yd2/cm2)

SA 	= 	Body surface area contacting carpet (cm2)

WF1 	= 	Weight fraction of commercial product in carpet (oz product/oz
carpet)

WF2 	= 	Weight fraction of OIT in commercial product (% a.i.)

WF3 	= 	Weight fraction of OIT transferred from carpet to skin
(unitless)

CF2 	= 	Conversion factor (28,350 mg/oz)

ET 	=  	Exposure time (hr/day)

CF3 	= 	Conversion factor (1 day/24 hr)

BW 	= 	Body weight (kg)

Assumptions

The product contains 46.5% a.i. by weight and is used in carpet at a
rate of 0.25% product by weight of material thus, the % a.i. in carpet
is 46.5% x 0.25% = 0.12%  (EPA Reg No. 67071-6).

The carpet density is 36 oz/yd2 based on a standard assumption (USAF
2003). 

It is assumed that 5% of the OIT on the carpet is transferred to skin
contacting the carpet (US EPA 2001).

For intermediate-term exposures, it was assumed that the skin area
contacting the vinyl was 6570 cm2 (median SA of a toddler, US EPA
1997b).

For intermediate-term exposures, the exposure duration was assumed to be
8 hrs/day (US EPA 2001) 

The body weight of a child was assumed to be 15 kg.

Results

	Table 4.4 shows the calculations of the short- and intermediate-term
dermal doses and MOEs for children contacting treated carpet.  Neither
of the MOEs is above the target MOE for the respective endpoint.  The
default residue transfer factor may not be representative of the actual
transfer value.  It is uncertain to what degree the residue is actually
being transferred because OIT is impregnated in the carpet matrix and it
is unknown whether or not the matrix is actually binding the OIT thereby
reducing the potential transfer.  Therefore, a residue transfer study
may help to refine the exposures and resulting MOEs.  Furthermore, if
the carpet use was limited to carpet backing and not the pile of the
carpet, it would be assumed that exposure is negligible and a
quantitative assessment would not be necessary to conduct.

Table 4.4.  Short- and Intermediate-term Dermal Exposures and MOEs for
Children Contacting Treated Carpet

Duration	% a.i.	Carpet density (oz/yd2)	OIT fraction transferred to skin
Skin surface area contacting carpet (cm2)	Exposure time (hrs/day)
Exposure a 

(mg/cm2 for ST; mg/kg/day for IT)	ST/IT MOE (Target MOE is 10 for ST,
100 for IT) b

ST	0.12%	36	5%	N/A	N/A	0.0073	9

IT	0.12%	36	5%	6,570	8	1.07	6

a 	Potential exposure for ST is expressed as mg a.i. per cm2 of exposed
skin; absorbed daily dose is mg/kg/day.  Equations used to estimate
exposure are presented above.

b	MOE = NOAEL/exposure estimate [Where: short-term NOAEL = 0.0674 mg/cm2
and intermediate-term NOAEL = 5.95 mg/kg/day for dermal exposures, Table
3.2]. 

Child Incidental Ingestion Exposure from Treated Carpet

	

Exposure Calculations

	

	Short- and intermediate-term exposures – There is potential for
short- and intermediate-term incidental oral exposures when children
exhibiting hand-to-mouth behavior come into contact with carpeting
treated with OIT.  Incidental oral exposures and MOEs were calculated
for children contacting treated carpet in residential or commercial day
care settings.  To determine child short- and intermediate-term
incidental oral exposure to OIT on carpeting, the following equation was
used:

 

where:

PDD 	= 	Potential daily dose (mg/kg/day)

D 	= 	Carpet weight density (oz/yd2)

CF1 	= 	Conversion factor (1.196x10-4 yd2/cm2)

SA 	= 	Surface area of the hands that contact both the treated area, and
the individual’s mouth (cm2/event)

WF1 	= 	Weight fraction of commercial product in carpet (oz product/oz
carpet)

WF2 	= 	Weight fraction of OIT in commercial product (oz OIT/oz carpet)

WF3 	= 	Weight fraction of OIT transferred from carpet to skin
(unitless)

SE 	= 	Saliva extraction efficiency (unitless fraction)

FQ 	= 	Frequency of hand-to-mouth events (events/hr)

ET 	=  	Exposure time (hr/day)

CF2 	= 	Conversion factor (28,350 mg/oz)

BW 	= 	Body weight (kg)

Assumptions

The product contains 46.5% a.i. by weight and is used in carpet at a
rate of 0.25% product by weight of material thus, the % a.i. in carpet
is 46.5% x 0.25% = 0.12% (EPA Reg No. 67071-6).

The carpet density is 36 oz/yd2 based on a standard assumption (USAF
2003). 

The surface area of the hands that contact both the treated area and the
individual’s mouth per exposure event is 20 cm2/event (US EPA 2001).

It is assumed that 5% of the OIT on the carpet is transferred to skin
contacting the carpet (US EPA 2001).

The saliva extraction efficiency is assumed to be 50% (US EPA 2001).

The frequency of hand-to-mouth events is assumed to be 20 events/hr for
ST exposures and 9.5 events/hr for IT exposures (US EPA 2001).

The time of exposure is assumed to be 8 hrs/day (US EPA 2001).

The body weight of a child was assumed to be 15 kg.

Results

	Table 4.5 shows the calculations of the short- and intermediate-term
incidental oral exposures and MOEs for children contacting treated
carpet.  Neither of the MOEs is above the target MOE for the respective
endpoint.  As previously stated, a residue transfer study may help to
refine the exposures and risks and changing the use pattern to carpet
backing only would eliminate the need for a quantitative exposure
assessment.

Table 4.5.  Short- and Intermediate-term Incidental Oral Exposures and
MOEs for Children Contacting Treated Carpet

Duration	% a.i.	Carpet density (oz/yd2)	OIT fraction transferred to skin
Saliva extraction efficiency	Surface area of hands (cm2)	Frequency of
hand-to-mouth events (events/hr)	Exposure time (hrs/day)	Exposure a 

(mg/kg/day)	ST/IT MOE (Target MOE is 100 for ST, 300 for IT) b

ST	0.12%	36	5%	50%	20	20	8	0.78	6

IT	0.12%	36	5%	50%	20	9.5	8	0.37	13

a 	Potential exposures are expressed as mg/kg/day; equations used to
estimate exposure are presented above.

b	MOE = NOAEL/exposure estimate [Where: ST and IT NOAEL = 5 mg/kg/day
for incidental oral exposures, Table 3.2]. 

		

	4.4.2.2	Treated Vinyl tc \l4 "4.4.2.1	Treated Vinyl 

	Vinyl tiles used for flooring can be treated with OIT during the
manufacturing process.  Therefore post application dermal and incidental
oral exposures to treated vinyl flooring may occur.  Since the vinyl is
actually impregnated with OIT and the vinyl can be used in a residential
setting there is potential for exposure to occur everyday, assuming that
OIT has a relatively long half life in indoor environments.  Therefore
both short- and intermediate-term exposures durations were assessed.

Child Dermal Exposure from Treated Vinyl

Exposure Calculations

	

	Short-term exposures - There is the potential for short-term dermal
exposures leading to dermal irritation when children come into contact
with vinyl treated with OIT. Potential exposures and MOEs were
calculated for children contacting treated vinyl in residential homes
(short-term exposure).  To determine child short-term exposure to OIT in
vinyl, the following equation was used:

PE = D x VT x CF1 x WF1 x WF2 x WF3 x WF4 x CF2

where:

PE 	= 	Potential exposure (mg/cm2)

D 	= 	Vinyl weight density (1.3 g/cm3)

VT	=	Vinyl thickness (3 mm)

CF1 	= 	Conversion factor (0.001 cm/mm)

WF1 	= 	Weight fraction of commercial product in vinyl (oz product/oz
vinyl)

WF2  	= 	Weight fraction of OIT in commercial product (oz OIT/oz)

WF3 	= 	Weight fraction of OIT available at the surface of impregnated
vinyl (unitless)

WF4 	= 	Weight fraction of OIT transferred from vinyl to skin (unitless)

CF2 	= 	Conversion factor (1000 mg/g)

	Intermediate-term exposures - There is also the potential for
intermediate-term vinyl exposures leading to systemic effects when
children come into contact with vinyl treated with OIT.  Exposures and
MOEs were calculated for children contacting treated vinyl in
residential homes.  To determine child intermediate-term exposure to OIT
in vinyl, the following equation was used:

PDD = D x VT x CF1 x SA x WF1 x WF2 x WF3 x WF4 x ET x CF2 x CF3

				BW

where:

PDD 	= 	Potential daily dose (mg/kg/day)

D 	= 	Vinyl weight density (1.3 g/cm3)

VT	=	Vinyl thickness (3 mm)

CF1 	= 	Conversion factor (0.001 cm/mm)

SA 	= 	Body surface area contacting vinyl (cm2)

WF1 	= 	Weight fraction of commercial product in vinyl (oz product/oz
vinyl)

WF2 	= 	Weight fraction of OIT in commercial product (oz OIT/oz vinyl)

WF3 	= 	Weight fraction of OIT available at the surface of impregnated
vinyl (unitless)

WF4 	= 	Weight fraction of OIT transferred from vinyl to skin (unitless)

CF2 	= 	Conversion factor (1000 mg/g)

ET 	=  	Exposure time (hr/day)

CF3 	= 	Conversion factor (1 day/ 24 hr)

BW 	= 	Body weight (kg)

Assumptions

The product contains 9.3% a.i. by weight and is used in vinyl at a rate
of 4% product by weight of material; thus, the % a.i. in the vinyl
flooring is 9.3% x 4 % = 0.37% (EPA Reg. No. 67071-43).

The vinyl density is 1.3 g/cm2 based on the density of polyvinyl
chloride, and vinyl flooring is assumed to be 3 mm thick. 

Because OIT is impregnated in the vinyl matrix, it was assumed that not
all of the additive was available for exposure.  Based on the results of
the OIT Task Force AMEM modeling, it was assumed that 0.9% of the OIT
impregnated within the vinyl matrix is available at the surface of the
flooring which is subsequently available for human exposure.

It was assumed that 10% of the OIT on the vinyl surface is transferred
to skin (US EPA 2001).

For intermediate-term exposures, it was assumed that the skin area
contacting the vinyl was 6570 cm2 (median SA of a toddler, US EPA
1997b).

For intermediate-term exposures, the exposure duration was assumed to be
4 hrs/day (US EPA 2001) 

The body weight of a child was assumed to be 15 kg.

Results

	Table 4.6 shows the calculations of the short- and intermediate-term
dermal doses and MOEs for children contacting treated vinyl.  The short-
and intermediate-term MOEs are above the target MOE of 10 and 100,
respectively, and therefore not a concern.  Although AMEM modeling was
conducted, it is uncertain to what degree the residue is actually being
transferred. 

Table 4.6.  Short- and Intermediate-term Dermal Exposures and MOEs for
Children Contacting Treated Vinyl Flooring

Duration	% a.i.	Vinyl density (g/cm3)	Vinyl flooring thickness (mm)
Fraction available on surface of vinyl 	Fraction transferred to skin
Skin surface area contacting vinyl (cm2)	Exposure time (hrs/day)
Exposure a 

(mg/cm2 for ST; mg/kg/day for IT)	ST/IT MOE (Target MOE is 10 for ST,
100 for IT) b

ST	0.37%	1.3	3	0.9%	10%	N/A	N/A	0.000013	5,200

IT	0.37%	1.3	3	0.9%	10%	6,570	4	0.00095	6,300

a 	Potential exposure for ST is expressed as mg a.i./ cm2 of exposed
skin; Potential exposure for IT is expressed absorbed daily dose is
mg/kg/day.  Equations used to estimate exposure are presented above.

b	MOE = NOAEL/exposure [Where: short-term NOAEL = 0.0674 mg/cm2 and
intermediate-term NOAEL = 5.95 mg/kg/day for dermal exposures, Table
3.2]. 

Child Incidental Ingestion Exposure from Treated Vinyl

	

Exposure Calculations

	

	Short- and intermediate-term exposures – There is potential for
short- and intermediate-term incidental oral exposures when children
exhibiting hand-to-mouth behavior come into contact with vinyl flooring
treated with OIT.  Incidental oral exposures and MOEs were calculated
for children contacting treated vinyl in residential or commercial day
care settings.  To determine child short- and intermediate-term
incidental oral exposure to OIT on vinyl flooring, the following
equation was used:

PDD = D x VT x CF1 x SA x WF1 x WF2 x WF3 x WF4 x SE x ET x CF2

				BW

where:

PDD 	= 	Potential daily dose (mg/kg/day)

D 	= 	Vinyl weight density (1.3 g/cm3)

VT	=	Vinyl thickness (3 mm)

CF1 	= 	Conversion factor (0.001 cm/mm)

SA 	= 	Surface area of the hands that contact both the treated area, and
the individual’s mouth (cm2/event)

WF1 	= 	Weight fraction of commercial product in vinyl (oz product/oz
vinyl)

WF2 	= 	Weight fraction of OIT in commercial product (oz OIT/oz vinyl)

WF3 	= 	Weight fraction of OIT transferred from vinyl to skin (unitless)

WF3 	= 	Weight fraction of OIT available on surface of impregnated vinyl
(unitless)

WF4 	= 	Weight fraction of OIT transferred from vinyl to skin (unitless)

SE 	= 	Saliva extraction efficiency (unitless fraction)

FQ 	= 	Frequency of hand-to-mouth events (events/hr)

ET 	=  	Exposure time (hr/day)

CF2 	= 	Conversion factor (1000 mg/g)

BW 	= 	Body weight (kg)

Assumptions

The product contains 9.3% a.i. by weight and is used in vinyl at a rate
of 4% product by weight of material; thus, the % a.i. in the vinyl
flooring is 9.3% x 4 % = 0.37% (EPA Reg. No. 67071-43).

The vinyl density is 1.3 g/cm2 based on the density of polyvinyl
chloride, and vinyl flooring is assumed to be 3 mm thick. 

The surface area of the hands that contact both the treated area and the
individual’s mouth per exposure event is 20 cm2/event (US EPA 2001).

Because OIT is impregnated in the vinyl matrix, it was assumed that not
all of the additive was available for exposure.  Based on the results of
the OIT Task Force AMEM modeling, it was assumed that 0.9% of the OIT
impregnated within the vinyl matrix is available at the surface of the
flooring which is subsequently available for human exposure.

It was assumed that 10% of the OIT on the vinyl surface is transferred
to skin contacting the flooring (US EPA 2001).

The saliva extraction efficiency was assumed to be 50% (US EPA 2000).

The frequency of hand-to-mouth events was assumed to be 20 events/hr for
ST exposures and 9.5 events/hr for IT exposures (US EPA 2001).

The time of exposure was assumed to be 4 hrs/day (US EPA 2001).

The body weight of a child was assumed to be 15 kg.

Results

	Table 4.7 shows the calculations of the short- and intermediate-term
incidental oral exposures and MOEs for children contacting treated
vinyl.  Both short- and intermediate-term MOEs are above the target MOE
of 100 and 300, respectively, and therefore not a concern.  

Table 4.7.  Short- and Intermediate-term Incidental Oral Exposures and
MOEs for Children Contacting Treated Vinyl Flooring

Duration	% a.i.	Vinyl density (g/cm3)	Vinyl flooring thickness (mm)
Fraction available on surface of vinyl 	Fraction transferred to skin
Saliva extraction efficiency	Surface area of hands (cm2)	Frequency of
hand-to-mouth events (events/hr)	Exposure time (hrs/day)	Exposure a 

(mg/kg/day)	ST/IT MOE (Target MOE is 100 for ST, 300 for IT) b

ST	0.37%	1.3	3	0.9%	10%	50%	20	20	4	0.00069	7,200

IT	0.37%	1.3	3	0.9%	10%	50%	20	9.5	4	0.00033	15,000

a 	Potential exposures are expressed as mg/kg/day; equations used to
estimate exposure are presented above.

b	MOE = NOAEL/exposure estimate [Where: ST and IT NOAEL = 5 mg/kg/day
for incidental oral exposures, Table 3.2]. 

	4.4.2.3	Textiles (Clothing)  tc \l4 "4.4.2.3	Textiles (Clothing) 

	Textiles (which includes fabric used for clothes) can be treated with
OIT during the manufacturing process.  Therefore post application dermal
and incidental oral exposures to treated clothing may occur.  It was
assumed that not all clothing is treated with OIT and the clothing that
is treated will not be worn everyday therefore exposure would occur
intermittently.  Thus only short-term exposures durations were assessed.

	OIT can also be used to prevent mildew in laundered fabric.  However,
it was determined that the amount used in the commercial laundry
application is much lower than the amount used from the materials
preservative use during manufacturing.  Therefore, the materials
preservative use represents all textile applications.

	It should be noted that leather can also be treated with OIT during the
tanning process.  Since dislodgeable residue data from treated leather
do not exist, residential post-application exposure to OIT on leather
(e.g., in clothing or furniture) is represented by the textiles
preservative use.  It was assumed that treated and then tanned and
rinsed leather results in lower OIT residues when compared to textiles
where the fabric is treated, laundered, and worn.	

Dermal Exposure to Treated Clothing

Exposure Calculations	

	There is the potential for short-term dermal exposure leading to dermal
irritation when adults or children contact clothing made of textiles
that have been commercially/industrially treated with OIT or laundered
using a mildewcide containing OIT.  To determine the short-term dermal
exposure to OIT for this scenario, the following equation was used:

 

where:

PE 	= 	Potential exposure (mg/cm2)

P 	= 	Textile density (mg/cm2)

WF1 	= 	Weight fraction of commercial product in textile (mg product/mg
textile)

WF2  	= 	Weight fraction of OIT in commercial product (mg OIT/mg
product)

WF3 	= 	Weight fraction of OIT transferred from textile to skin
(unitless)

Assumptions

The product contains 46.5% a.i. by weight and is applied to textiles at
a rate of 0.25% product by weight of material; thus, the % a.i. in the
textiles is 46.5% x 0.25% = 0.12%.

The textile density is 10 mg/cm2 based on the density of mixed cotton
and synthetics (HERA 2003). 

Since there are no clothing specific residue transfer factors available
at this time a default of 100% and 5% were used.  The 5% residue
transfer factor is based on the default residue transfer from treated
carpets and a confirmatory study is needed to support this assumption
(US EPA 2001).

Results

	Table 4.8 shows the calculation of the short-term dermal exposures and
MOEs for children contacting treated textile/clothing.  Since the MOE is
below the target MOE of 10 when using a transfer factor of 100% but
above the target MOE when using the 5% transfer factor, a confirmatory
study is required.

	It should be noted that although this scenario also represents the
laundered clothing scenarios, the transfer factors may be different. 
The fabrics preserved in the manufacturing facility may have a lower
transfer factor than those laundered due to the matrix effects.  It
would seem reasonable that the residues on the laundered fabrics are on
the surface of the material rather than “impregnated” thus having a
higher dislodgeable potential.  

Table 4.8.  Short-term Dermal Exposure and MOE for Adults and Children
Contacting Treated Clothing

Duration	% a.i.	Cloth density (mg/cm2)	fraction transferred to skin
Exposure a 

(mg/cm2)	ST MOE 

(Target MOE is 10) b

ST	0.12%	10	100%	0.012	6

ST	0.12%	10	5%	5.8E-04	116

a 	Potential exposure is expressed as mg/cm2; equation used to estimate
exposure is presented above.

b	MOE = NOAEL/exposure estimate [Where: ST and IT NOAEL = 0.0674 mg/cm2
for dermal irritation exposures, Table 3.2]. 

Child Incidental Ingestion Exposure from Wearing Treated Clothing

	

Exposure Calculations

	

	There is the potential for short-term incidental ingestion exposures
when children come into contact with textiles treated with OIT.  For
reasons specified previously, only short-term exposures were assessed. 
The exposure and MOE were calculated for children contacting treated
textiles.  To determine child short-term oral exposure to OIT in
textiles, the following equation was used:

 

where:

PDD 	= 	Potential daily dose (mg/kg/day)

P 	= 	Textile weight density (mg/cm2)

WF1 	= 	Weight fraction of commercial product in textile (mg product/mg
textile)

WF2  	= 	Weight fraction of OIT in commercial product (mg OIT/mg
product)

SM	=	Surface area of fabric that is mouthed (cm2/day)

SE 	= 	Saliva extraction efficiency (unitless fraction)

BW 	= 	Body weight (kg)

Assumptions

The product contains 46.5% a.i. by weight and is applied to textiles at
a rate of 0.25% product by weight of material; thus, the % a.i. in the
textiles is 46.5% x 0.25% = 0.12%.

The textile density is 10 g/cm2 based on the density of mixed cotton and
synthetics (HERA 2003). 

The area of fabric that is mouthed per day is assumed to be 100 cm2 (AD
standard assumption)

The saliva extraction efficiency is assumed to be 50% (US EPA 2001).

The body weight of a child was assumed to be 15 kg.

Results

	Table 4.9 shows the calculations of the short-term incidental oral
exposure and MOE for children contacting treated clothing.  The
resulting MOE is above the target MOE of 100 and therefore not a
concern.

Table 4.9.  Short-term Incidental Oral Exposures and MOEs for Children
Contacting Treated Clothing

Duration	% a.i.	Cloth density (mg/cm2)	Area of fabric mouthed (cm2)
Saliva extraction efficiency	Exposure a 

(mg/kg/day)	ST MOE (Target MOE is 100 for ST) b

ST	0.12%	10	100	50%	0.039	130

a 	Potential exposures are expressed as mg/kg/day; equations used to
estimate exposure are presented above.

b	MOE = NOAEL/exposure estimate [Where: ST NOAEL = 5 mg/kg/day for
incidental oral exposures, Table 3.2]. 

	4.4.2.4	Mattresses tc \l4 "4.4.2.2	Mattresses 

	Mattresses including ticking, covers, and foam can be treated with OIT
during the manufacturing process.  Therefore post application dermal
exposures to treated mattresses may occur.  It was assumed that exposure
to a mattress cover will represent exposure to all other mattress
components.  Since the mattress cover is actually impregnated with OIT
and it can be used everyday, both short- and intermediate-term exposures
durations were assessed.

Dermal Exposure to Treated Mattress Covers

Exposure Calculations	

	Short-term - There is the potential for short-term dermal exposures
leading to irritation when adults and children contact mattress covers
that have been treated with OIT during the manufacturing process.  To
determine the short-term dermal exposure to OIT for this scenario, the
following equation was used:

 

where:

PE 	= 	Potential exposure (mg/cm2)

P 	= 	Fabric density (mg/cm2)

WF1 	= 	Weight fraction of commercial product in mattress (mg product/mg
mattress)

WF2  	= 	Weight fraction of OIT in commercial product (mg OIT/mg
product)

WF3 	= 	Weight fraction of OIT transferred from mattress to skin
(unitless)

PF	= 	Protection factor from single layer of clothing or sheet
(unitless)

	Intermediate-term exposures - There is also the potential for
intermediate-term exposures leading to systemic effects when adults and
children come into contact with mattress covers treated with OIT,
through the regular use of the mattress.  Exposures and MOEs were
calculated for children contacting treated mattresses in residential
homes.  To determine child intermediate-term exposure to OIT in
mattresses, the following equation was used:

 

where:

PDD 	= 	Potential daily dose (mg/kg/day)

P	= 	Mattress textile weight density (mg/cm2)

WF1 	= 	Weight fraction of commercial product in mattress (mg product/mg
mattress)

WF2 	= 	Weight fraction of OIT in commercial product (mg OIT/mg product)

WF3 	= 	Weight fraction of OIT transferred from vinyl to skin (unitless)

PF	=	Protection factor from single layer of clothing/sheet (%)

SA 	= 	Body surface area contacting mattress (cm2)

ET 	=  	Exposure time (hr/day)

CF 	= 	Conversion factor (1 day/ 24 hr)

BW 	= 	Body weight (kg)

Assumptions

The product contains 20% a.i. by weight and is applied to textiles at a
rate of 2% product by weight of material; thus, the % a.i. in the
mattress cover is 20% x 2% = 0.4%.

The mattress cover density is assumed to be 10 g/cm2 based on the
density of mixed cotton and synthetics (HERA 2003). 

Since there are no mattress specific residue transfer factors available
at this time a default of 100% and 5% were used.  The 5% residue
transfer factor is based on the default residue transfer from treated
carpets and a confirmatory study is needed to support this assumption
(US EPA 2001).

The protection factor inhibiting exposure to OIT 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 2,955 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 a toddler) (NAFTA guidance per US EPA
1997).

The time of exposure is assumed to be 10 hrs/day (US EPA 1997b)

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 4.10 shows the calculation of the short and intermediate-term
dermal exposure and MOE for children and adults contacting treated
mattress covers.  Since the ST MOE is below the target MOE of 10 when
using a transfer factor of 100% but above the target MOE when using the
5% transfer factor, a confirmatory study is required.  Additionally, the
IT MOE for children using a 5% transfer factor is below the MOE of 100
and is of concern.  

Table 4.10.  Short- and Intermediate-term Dermal Exposure and MOE for
Children and Adults Contacting Treated Mattress Covers

Duration	% a.i.	Mattress density (mg/cm2)	Fraction transferred to skin
Skin surface area contacting mattress (cm2)	Protective factor

	Exposure Time (hrs/day)	Exposure a 

(mg/cm2 for ST; mg/kg/day for IT)	MOE 

(Target MOE is 10 for ST, 100 for IT) b

Children

ST	0.40%	10	100%	N/A	50%	N/A	0.020	3

ST	0.40%	10	5%	N/A	50%	N/A	0.0010	67

IT	0.40%	10	100%	2,955	50%	10	1.6	4

IT	0.40%	10	5%	2,955	50%	10	0.082	73

Adults

ST	0.40%	10	100%	N/A	50%	N/A	0.020	3

ST	0.40%	10	5%	N/A	50%	N/A	0.0010	67

IT	0.40%	10	100%	9,220	50%	10	1.1	5

IT	0.40%	10	5%	9,220	50%	10	0.055	110

a 	Potential exposure for ST is expressed as mg a.i. per cm2 of exposed
skin; absorbed daily dose is mg/kg/day.  Equations used to estimate
exposure are presented above.

b	MOE = NOAEL/exposure estimate [Where: short-term NOAEL = 0.0674 mg/cm2
and intermediate-term NOAEL = 5.95 mg/kg/day for dermal exposures, Table
3.2]. 

4.4.2.5	Plastics tc \l4 "4.4.2.4	Plastics 

	Plastics and polymers used in toys can be treated with OIT during the
manufacturing process.  Therefore children’s post application
incidental oral exposures to treated toys may occur.  It was assumed
that not all plastic toys are treated with OIT and the toys that are
treated will not be used everyday therefore exposure would occur
intermittently.  Thus only short-term exposures durations were assessed.

Child Incidental Ingestion Exposure from Treated Plastic

	

Exposure Calculations

	

	Short-term exposures – There is potential for short- term incidental
ingestion exposures when children come into mouth plastic toys treated
with OIT.  To determine child short-term exposure to OIT in plastic
toys, the following equations were used:

PDD = SR x SE x SA

	      BW							

where: 

PDD	= 	potential daily dose (mg/kg/day);

SR 	= 	surface residue (mg/cm2);

SE	=	saliva extraction efficiency (unitless fraction)

SA	=	surface area of toy mouthed (cm2/day)

BW 	= 	body weight of a 12 month old infant (kg).

And

SR = % a.i x W x CF x F	

	         SA					

where:

SR	=	surface residue (mg a.i./cm2)

% a.i.	=	fraction active ingredient in toy by total weight (unitless)

W	=	weight of toy (g)

CF	=	conversion factor (1,000 mg/g)

F	=	fraction additive available at the surface of the toy (unitless)

SA	=	surface area of toy (cm2)

Assumptions

It is assumed that 500 cm2 is a representative surface area of plastic
that is mouthed (AD standard assumption).

Since chemical specific leaching data were not available, the actual
amount of active ingredient at the surface of the toy which is available
for mouthing is based on the following assumptions

The toy is manufactured from ABS or polystyrene plastic;

The diffusion of the active ingredient available at the surface of the
toy to the child’s mouth is allowed to reach equilibrium; and 

No more than 0.5% of the additive is available on the surface of the toy
for each mouthing event.

The weight of a 500 cm2 toy is 50 g, which is based on data showing that
a polyethylene highchair sample with a surface area of 12.7 cm2 weighs
1.3072 g (i.e., 0.1 g/cm2) (AD standard assumption).

The product contains 20% a.i. by weight and is used in plastic at a rate
of 2% product by weight of material; thus, the % a.i. in plastic is 20%
x 2% = 0.40%.

The saliva extraction efficiency is assumed to be 50% (US EPA 2001).

The body weight of a child was assumed to be 15 kg.

Results

	Table 4.12 shows the calculations of the short-term incidental oral
exposure and MOE for children mouthing treated plastic toys.  The ST MOE
is above the target MOE of 100 and is not of concern.

Table 4.12.  Short-term Incidental Oral Exposure and MOE for Children
Mouthing Treated Plastic Toys

Duration	% a.i.	Plastic Weight (g)	Fraction OIT available on plastic
surface 

	Surface area mouthed (cm2)	Surface area of plastic (cm2)	Saliva
extraction efficiency

	Exposure a 

(mg/kg/day)	ST MOE (Target MOE is 100 for ST) b

ST	0.40%	50	0.5%	500	500	50%	0.033	152

a 	Potential exposures are expressed as mg/kg/day; equations used to
estimate exposure are presented above.

b	MOE = NOAEL/exposure estimate [Where: ST NOAEL = 5 mg/kg/day for
incidental oral exposures, Table 3.2]. 

4.4.3	Data Limitations/Uncertainties tc \l3 "4.4.3	Data
Limitations/Uncertainties 

	There are several data limitations and uncertainties associated with
the residential handler and postapplication exposure assessments which
include the following:

The dermal exposure estimate for the residential painter scenario
applying treated paint was based on wet film thickness data from a study
where the user’s hands were immersed twice in mineral oil; no
information specific to the wet film thickness of paint was identified. 
The method employed may result in an underestimate of dermal exposures
to paint.  The assessment could be refined using a dermal irritation
study where paint is the test substance.

There are no available data on the quantity of residue dislodged from
treated leather.  As a result, it was assumed that the residential post
application exposure from textiles is representative of post-application
exposures from leather.  

A confirmatory study is needed to verify the 5% transfer factor for
clothing and mattress covers.

The default residue transfer factors for carpeting (5%) and clothing
(5%) may not be representative of the actual transfer values.  It is
uncertain to what degree the residue is actually being transferred
because OIT is impregnated in the matrix and it is unknown whether or
not the matrix is actually binding the OIT thereby reducing the
potential transfer.

Although AMEM modeling was conducted, it is uncertain to what degree the
residue is actually being transferred from the vinyl flooring.

The textile preserved at the manufacturing facility scenario also
represents the laundered clothing scenario, however the transfer factors
may be different.  The fabrics preserved in the manufacturing facility
may have a lower transfer factor than those laundered due to the matrix
effects.  It would seem reasonable that the residues on the laundered
fabrics are on the surface of the material rather than “impregnated”
thus having a higher dislodgeable potential.  

The method used to estimate exposure from mouthing treated plastic toys
is conservative because it does not account for washing of the toy or
depletion of residue after each toy-to-mouth episode.  However, the
amount of OIT residue remaining in plastic toys is largely unknown.

5.0	RESIDENTIAL AGGREGATE RISK ASSESSMENT AND CHARACTERIZATION tc \l1
"5.0	RESIDENTIAL AGGREGATE RISK ASSESSMENTS AND RISK CHARACTERIZATION 

	

5.1	Acute and Chronic Dietary Aggregate Risk

	This is included in the Preliminary Risk Assessment.

5.2	Short and Intermediate Term Aggregate Risk tc \l2 "5.2	Short-,
Intermediate-, and Long-Term Aggregate Risk 

	In order for a pesticide registration to continue, it must be shown
“that there is reasonable certainty that no harm will result from
aggregate exposure to pesticide chemical residue, including all
anticipated dietary exposures and other exposures for which there are
reliable information.”  Aggregate exposure is the total exposure to a
single chemical (or its residues) that may occur from dietary (i.e.,
food and drinking water), residential, and other non-occupational
sources, and from all known or plausible exposure routes (oral, dermal,
and inhalation).  However, this assessment only addresses non-dietary
residential aggregate exposures and risks.  The Preliminary Risk
Assessment (PRA) of the RED will address the complete aggregate
assessment including both dietary and non-dietary residential exposures
and risks. 

	In performing aggregate exposure and risk assessments, the Office of
Pesticide Programs has published guidance outlining the necessary steps
to perform such assessments (General Principles for Performing Aggregate
Exposure and Risk Assessments, November 28, 2001; available at
http://www.epa.gov/pesticides/trac/science/aggregate.pdf).  Steps for
deciding whether to perform aggregate exposure and risk assessments are
listed, which include: identification of toxicological endpoints for
each exposure route and duration; identification of potential exposures
for each pathway (food, water, and/or residential);  reconciliation of
durations and pathways of exposure with durations and pathways of health
effects; determination of which possible residential exposure scenarios
are likely to occur together within a given time frame; determination of
magnitude and duration of exposure for all exposure combinations;
determination of the appropriate technique (deterministic or
probabilistic) for exposure assessment; and determination of the
appropriate risk metric to estimate aggregate risk

  SEQ CHAPTER \h \r 1 Short- and Intermediate-Term Aggregate Exposures
and Risks

	Short- and intermediate-term aggregate exposures and risks were
assessed for adults and children that could be exposed to OIT residues
from the use of products in non-occupational environments.  The
following lists summarize all of the non-dietary, non-occupation
potential sources of OIT exposures for adults and children:

Adult OIT exposures sources:

Applying of OIT preserved paint in residential settings

Wearing treated clothing

Sleeping on a treated mattress

	

Child OIT exposures sources:

Post-application exposures to impregnated residues on carpeted surfaces

Post-application exposures to impregnated residues on hard surfaces
(i.e., vinyl floors)

Wearing treated clothing

Sleeping on a treated mattress

Playing with OIT preserved plastic toys

	The use patterns of the products and probability of co-occurrence must
be considered when selecting scenarios for incorporation in the
aggregate assessment.  For example, homeowner painting activities occur
only once or twice a year; therefore the probability of co-occurrence
and the potential for exposure to residues from this use with other OIT
products on the same day is highly unlikely.    SEQ CHAPTER \h \r 1
Because most of the OIT products are used as a materials preservative in
the manufacturing of various materials and exposure to some of these
materials (e.g., mattresses, carpets, vinyl tiles) can occur on a
continuous basis, they were included in the aggregate assessments.   It
should be noted that based on the probability of co-occurrence of the
uses that have intermediate-term exposure potential, it was determined
that adult intermediate-term aggregate assessment was not necessary to
conduct.  However, child intermediate-term aggregate assessments should
be conducted for carpet and mattress exposure but since the individual
risks are of concern the aggregate risks will also be of concern and
there is no need to quantitatively assess this scenario.   Table 5.1
summarizes the scenarios included in the short-term aggregate
assessments.

Table 5.1:  Summary of Exposure Scenarios Included in the Short-Term
Aggregate Assessments

	Short-term Aggregate

Adults 	Dermal:

exposure to residues in fabrics/clothing preserved during manufacturing 

exposure to residues in mattresses preserved during manufacturing 

Children	Dermal:

exposure to residues in fabrics/clothing preserved during manufacturing 

exposure to residues in mattresses preserved during manufacturing

exposure to residues in vinyl tiles preserved during manufacturing

	Oral:

exposure to residues in fabrics/clothing preserved during manufacturing 

exposure to residues in polymers (toys) preserved during manufacturing



  SEQ CHAPTER \h \r 1 It should be reiterated that the post-application
exposures to carpet OIT residues alone are of concern to the Agency. 
Incorporation of this scenario in the aggregate assessment would result
in risks of concern.  Therefore, the carpet scenario was not
incorporated in the aggregate assessment.   If these exposures did not
result in risks of concern, then they would have been included in the
aggregate assessments instead of exposures to vinyl floors.  

Since the endpoint for each route of exposure was based on a route
specific study resulting in different effects, separate route specific
aggregate assessment were conducted.  The Total MOE method outlined in
OPP guidance for aggregate risk assessment (September 1, 2000, Standard
Operating Procedure (SOP) for Incorporating Screening Level Estimates of
Drinking Water Exposure into Aggregate Risk Assessments) was utilized. 
This method was used because the oral, dermal and inhalation endpoints
have the same uncertainty factors or target MOEs.   The target MOE for
all ST dermal exposure is 10 and ST oral is 100.   The general equation
used to estimate total or aggregate MOEs is:  

Aggregate MOE = 1 / ((1/MOEroute 1, scenario 1) + (1/ MOEroute1,
scenario 2) + (1/MOE route 1, scenario n))

 

Where, route represents oral or dermal exposures, and scenario
represents post-app carpet, mattress, etc.

Tables 5.2 and 5.3 present the resulting MOEs for the short-term dermal
and short- oral aggregate assessments, respectively.    SEQ CHAPTER \h
\r 1 The short-term dermal aggregate MOEs for adults and children were
above the target MOE of 10. However, the short-term oral aggregate MOE
for children was below the target MOE of 100 and therefore a concern.

Table 5.2 ST Dermal Aggregate Assessments

	MOEs

Exposure Route	Vinyl	Clothing	Mattress	Aggregate	Target MOE

Adults 	 

 

 

   dermal	NA	116	67	42	10

Child	 

 

 

   dermal	5,200	116	67	42	10

a: Aggregate MOE = 1/((1/MOEvinyl) + (1/MOEclothing) + (1/MOEmattress))

Table 5.3 ST Oral Aggregate Assessments

	MOEs

Exposure Route	Vinyl	Clothing	Toys	Aggregate	Target MOE

Child	 

 

 

  incidental oral	7,200	130	150	69	100

a: Aggregate MOE = 1/((1/MOEvinyl) + (1/MOEclothing) + (1/MOEtoys))

6.0	OCCUPATIONAL EXPOSURE ASSESSMENT tc \l1 "6.0	OCCUPATIONAL EXPOSURE
AND RISK 

	6.1	Summary of Registered Uses tc \l2 "6.1	Summary of Registered Uses 

	The exposure scenarios assessed in this document for the representative
uses selected by AD are shown in Table 6.1.  The table also shows the
maximum application rates associated with the representative use and the
appropriate EPA Registration number for the product label.  For
handlers, the representative uses assessed include use as a material
preservative (metalworking fluid, paint/coatings, plastics, leather, and
mattresses), industrial biocide for cooling water tower systems and a
wood preservative.  

	Potential occupational handler exposures can occur during the
preservation of materials that are used for institutional and industrial
uses, along with the use of cooling water tower biocides and wood
preservatives.  The “preservation of materials” refers to the
scenario of a worker adding the preservative to the material being
treated (metalworking fluid, paint, textiles, etc.) through either
liquid pour or liquid pump methods.  Liquid pour refers to transferring
the antimicrobial product from a small container to an open vat.  Liquid
pump refers to transferring the preservative by connecting/disconnecting
a chemical metering pump from a tote or by gravity flow.  Due to their
complexity or special considerations, exposures for some scenarios are
discussed in separate sections, including exposures for a machinist
working with metalworking fluids (Section 6.4), short-term dermal
exposures for a professional painter applying treated paint (Section
6.5.1), inhalation exposures for a professional painter using an airless
sprayer (Section 6.5.2), and exposures that occur during leather
processing (Section 6.6). 

It should be noted that short-term dermal exposures were not assessed
for the most occupational handler scenarios because the endpoint is
based on dermal irritation.  Instead, dermal irritation exposures and
risks will be mitigated using default personal protective equipment
requirements based on the toxicity of the end-use product.  To minimize
dermal exposures, the minimum PPE required for mixers, loaders, and
others exposed to end-use products that result in classification of
category I, II, or III for skin irritation potential will be a
long-sleeve shirt, long pants, shoes, socks, chemical-resistant gloves,
and a chemical-resistant apron.  Once diluted, if the concentration in
the diluted solution will result in classification of toxicity category
IV for skin irritation potential, then the chemical-resistant gloves and
chemical-resistant apron can be eliminated for applicators and others
exposed to the dilute product. Note that chemical-resistant eyewear will
be required if the end-use product is classified as category I or II for
eye irritation potential. 

	However, gloves are not a viable mitigation option for in-can
preservative products such as paints because it is not feasible to label
the end-use product with the biocide information.  Furthermore, gloves
are also not a viable mitigation option for machinist using biocide
treated metalworking fluids.  Therefore, short-term dermal exposures
were assessed for these scenarios.

	Further note that no total MOEs (i.e., that account for combined
exposures via dermal and inhalation routes) were calculated for
occupational use scenarios because the toxicological endpoints for
dermal and inhalation exposures are different.

Table 6.1.  Representative Exposure Scenarios Associated with
Occupational Exposures to Octhilinone



Representative Use	Method of Application	Exposure Scenario	Registration
#	Application Rate

Material Preservatives

Metalworking fluid	Liquid pour 

Liquid pump

Use of treated metalworking fluid	Handler (worker pouring preservative
into fluid being treated): IT dermal; ST and IT inhalation

Machinist:  ST and IT dermal and inhalation	67071-6

	0.0075% a.i. by weight (75 ppm a.i.)

Paint1	Preservation of paint

Liquid pour

Liquid pump

Professional painter

Brush/roller

Airless sprayer	Handler: IT dermal; ST and IT inhalation

Professional Painter:

ST dermal and inhalation	67071-31	0.23% a.i. by weight (13.8 lb
product/1000lb paint x 16.84% a.i. in product)



Plastics and vinyl2	Liquid pour 

Liquid pump

	Handler: IT dermal; ST and IT inhalation	81348-8	0.4% a.i. by weight
(2% product by weight of material treated x 20% a.i. in product)

Leather	Liquid pour 

Metering pump	Handler: IT dermal; ST and IT inhalation	707-121	0.019%
a.i. by weight hides (3,530 ppm product in hides (wet weight) x 5.5%
a.i. in product)



Textiles	Liquid pour 

Liquid pump

	Handler: IT dermal; ST and IT inhalation

	67071-6	0.12% a.i. by weight (0.25% product by weight of material
treated x 46.5% a.i. in product)

Mattresses	Mechanical metering pump	Handler: IT dermal; ST and IT
inhalation	81348-8	0.4% a.i. by weight (2% product by weight of material
x 20% a.i. in product)

Industrial Processes and Water Systems

Cooling tower waters3	N/A	N/A	707-100	N/A

Wood Preservatives

Wood preservative 	High Pressure Spray

	Handler: IT dermal; ST and IT inhalation 	73612-1	0.096% a.i. solution
(80 liters product/ 1000 liters water x 1.2% a.i. in product)

1 Preservation of paint is assumed to be representative of various
exposures related to the incorporation of  OIT into liquid substances
during production (including sealants, adhesives, and other viscous
materials) as well as addition of OIT to solid products where addition
of product occurs during manufacture; e.g., carpets, molded goods,
etc.).

2 Assumed to be representative of exposures related to addition of OIT
to plastics, polymers, vinyl, and similar products during the
manufacturing process.

3 Use directions on label are described for manufacturing use product
only; no end uses are provided.  Therefore, no exposure assessment was
conducted for this scenario.

	6.2	Occupational Handler Exposures tc \l2 "6.2	Occupational Handler
Exposures 

	The occupational handler scenarios included in Table 6.1 were assessed
to determine dermal and inhalation exposures.  The general assumptions
and equations that were used to calculate occupational handler 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 through 3.  However, for the occupational scenarios in which CMA data
were insufficient, other data and methods were applied. 

	

Unit Exposure Values (UE):  The majority of the dermal and inhalation
unit exposure values were taken from the proprietary CMA antimicrobial
exposure study (US EPA 1999: DP Barcode D247642) or from the Pesticide
Handler Exposure Database (US EPA 1998).  

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.

Metalworking fluid: CMA metal fluid gloved data.  The dermal UE is 0.184
mg/lb ai and the inhalation UE is 0.00854 mg/lb ai. The values are based
on 8 replicates where the test subjects were wearing a single layer of
clothing and chemical resistant gloves.

Plastics, paints, and textiles: CMA preservative gloved data.  The
dermal UE is 0.135 mg/lb ai and the inhalation UE is 0.00346 mg/lb ai.
The values are based on 2 replicates where the test subjects were
wearing a single layer of clothing and chemical resistant gloves.

For the liquid pump scenarios, 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.

Metalworking fluid:  CMA metal fluid gloved data.  The dermal UE is
0.312 mg/lb a.i. and the inhalation UE is 0.00348 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.  

Plastics, paint, textiles, and mattresses:  CMA preservative gloved
data.  The dermal UE is 0.00629 mg/lb a.i. and the inhalation UE is
0.000403 mg/lb a.i. for inhalation.  The values are based on two
replicates where the test subjects were wearing a single layer of
clothing and chemical resistant gloves. 

For the roller/brush scenarios, the occupational PHED inhalation unit
exposure value of 0.28 mg/lb a.i for paintbrush applications (PHED
scenario 22) was used.

For the high pressure spray scenario, dermal and inhalation unit
exposure values were taken from PHED (MLA liquid/open pour/high pressure
spray).  These unit exposure data were monitored in greenhouses where
the applications were made to floors, benches, and overhead plants.  The
dermal and inhalation unit exposure values are 1.6 mg/lb a.i. and 0.012
mg/lb a.i., respectively.  It should be noted that protection factors
were incorporated in these unit exposure values because the wood
preservative labels require PPE (i.e., gloves, overalls and respiratory
protection). 

Quantity handled/treated:  The quantity handled/treated values were
estimated based on information from various sources.  The following
assumptions were made:

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:

Metalworking fluid:  2,502 lbs (approximately 300 gallons, where the
density of the fluid is assumed to be that of water, 8.34 lb/gal) (AD
assumption).

Plastics and paint:  20,000 lbs (approximately 2,000 gallons, where
paint/plastic density is 10 lb/gal) (AD assumption).

Textiles:  10,000 lbs of textiles treated per day (AD assumption).

For the liquid pump scenarios the quantity that is handled depends on
the material that is being treated.  The following values were used for
the different materials:

Metalworking fluid:  2,502 lbs (approximately 300 gallons, where the
density of the fluid is assumed to be that of water, 8.34 lb/gal) (AD
assumption). 

Plastics and paint:  200,000 lbs (approximately 20,000 gallons, where
paint/plastic density is 10 lb/gal) (AD assumption).

Textiles:  10,000 lbs of textiles treated per day based on standard
assumptions.

Mattresses:  It was assumed that 1,300 kg (2,860 lb) of mattress ticking
are treated per worker day in a standard textile mill (AD assumption).  

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 paint are used (US EPA 2001).

For the high pressure/high volume spray wood treatment scenario, it was
assumed that 2,195 lbs (263 gallons (or 1,000 liters) where the density
of the solution is assumed to be that of water, 8.34 lb/gal) of solution
were handled in one day.  This was based on the label (73612-1) use rate
directions indicating that the working solution is prepared on a 1,000
liter basis (i.e., mix 80 liters of concentrate per 1,000 liters of
water).  This value could be further refined from input from
registrants.

Duration of Exposure:  Exposures and MOEs were calculated for the
intermediate-term duration for dermal exposures and short- and
intermediate-term durations for inhalation exposures for occupational
handlers using the appropriate endpoints in Table 3.2.  Short-term
dermal exposures were not assessed for most occupational uses.  It was
assumed that dermal irritation via short-term exposures will be
mitigated through the use of personal protective equipment (PPE) as
specified on the product labels.  The professional painter scenario is
the exception; gloves are not a viable mitigation option for in-can
preservative products such as paints because it is not feasible to label
these types of end-use products with the biocide information (exposures
for this scenario are presented in Section 6.5). 

For intermediate-term dermal exposures (resulting in the potential for
systemic effects), the PPE used by occupational users were assumed, at a
minimum, to be a long-sleeve shirt, long pants, shoes, socks,
chemical-resistant gloves, and goggles or face shield.  For the
professional painter scenario, no intermediate-term exposures were
assessed because it is assumed that painters will not use OIT-preserved
paint on a continuous basis.

Table 6.2 Short- and Intermediate-Term Exposures and MOEs for
Occupational Handlers using OIT



Exposure Scenario	

Method of Application	Unit Exposure

(mg/lb a.i.)	App. Rate	Quantity Handled/ Treated per day	Absorbed Daily
Dose (mg/kg/day)	MOEe



Dermala	Inhalation

	IT Dermal c

	ST/IT Inhalation c mg/kg/day	ST/IT

Air Concd

mg/m3	IT Dermal 

(Target MOE = 100)	ST/IT Inhalation

(Target MOE = 30)

Preservation of metalworking fluid	Liquid pour	0.184	0.0085	0.0075% a.i.
by weight	2,502 lbs

 (300 gal) 	0.00049	2.3E-05	0.000199	12,000	370

	Liquid pump	0.312	0.00348	0.0075% a.i by weight	2,502 lbs

 (300 gal)	0.00084	9.3E-06	0.000082	7,100	890

Preservation of plastics and vinyl	Liquid pour	0.135	0.00346	0.4% a.i.
by weight	20,000 lbs

(2,000 gal)	0.15	0.0040	0.034600	39	2

	Liquid pump	0.00629	0.000403	0.4% a.i. by weight	200,000 lbs

(20,000 gal)	0.072	0.0046	0.040300	83	2

Preservation of paint	Liquid pour	0.135	0.00346	0.23% a.i. by weight
20,000 lbs

(2,000 gal)	0.090	0.0023	0.019895	67	4

	Liquid pump	0.00629	0.000403	0.23% a.i. by weight	200,000 lbs

(20,000 gal)	0.041	0.0026	0.023173	140	3

Preservation of textiles 	Liquid pour	0.135	0.00346	0.12% a.i. by weight
10,000 lbs	0.023	0.00059	0.005190	260	14

	Liquid pump	0.00629	0.000403	0.12% a.i. by weight	10,000 lbs	0.0011
6.9E-05	0.000605	5,500	120

Preservation of mattresses	Liquid pump	0.00629	0.000403	0.4% a.i. by
weight	2,860 lbs

(1,300 kg)	0.0010	6.6E-05	0.000576	5,800	130

Application of paint by professionals	Brush/ roller	NC b	0.28	0.23% a.i.
by weight	50 lbs

(5 gal)	NC	0.00046	0.004025	NC	25

Mixing, loading, and applying wood preservative solution	High
pressure/high volume spray	2.5	0.12	0.096% a.i.	2,195 lbs

(263 gal)	0.048	0.00036	0.0032	130	200

ST = short-term, IT = intermediate-term, NC = Not conducted

a	With the exception of the scenario for application of paint, all
dermal unit exposure estimates used for occupational handler scenarios
represent exposures incurred assuming the use of PPE (at least a
long-sleeve shirt and long pants plus gloves), as specified on the
product labels.  For the application of paint by professional painters,
dermal exposures were calculated for baseline dermal exposures
(long-sleeve shirt, long pants, and no gloves).

b	NC = not conducted. Short-term dermal exposures during the application
of paint resulting in the potential for dermal irritation are evaluated
in Section 6.5.  Intermediate-term dermal exposures during the
application of paint are not assessed because it was assumed that
professional painters will not use OIT-preserved paint on a continuous
basis.

c	Absorbed Daily dose (mg/kg/day) = [unit exposure (mg/lb ai) *
application rate (%a.i. by weight) * quantity treated or handled
(lb/day) / Body weight (70 kg).

d	Air conc (mg/m3) = dose (mg/kg/day) x 70 kg x light activity
inhalation rate (day/ 8m3)

e	MOE = NOAEL (mg/kg/day) / Absorbed Daily Dose [Where IT dermal NOAEL =
5.95 mg/kg/day and the ST/IT inhalation 8 hr HEC = 0.073 mg/m3 and ST/IT
inhalation 6 hr HEC = 0.098 mg/m3 for professional painter] 

Exposure Calculations and Results 			

	The calculated dermal and inhalation exposures and MOEs are shown in
Table 6.2.  All MOEs in the occupational setting were above the target
MOE of 100 for IT dermal and 30 for ST and IT inhalation exposures
except for the following scenarios: 

IT dermal exposure resulting from liquid pour for preservation of
plastics and vinyl:  MOE = 39.

ST/IT inhalation exposures resulting from liquid pour for preservation
of plastics and vinyl:  MOE = 2.

IT dermal exposure resulting from liquid pump for preservation of
plastics and vinyl:  MOE = 83.

ST/IT inhalation exposures resulting from liquid pump for preservation
of plastics and vinyl:  MOE = 2.

IT dermal exposure resulting from liquid pour for preservation of paint:
 MOE = 67.

ST/IT inhalation exposures resulting from liquid pour for preservation
of paint:  MOE = 4.

ST/IT inhalation exposures resulting from liquid pump for preservation
of paint:  MOE = 3.

ST/IT inhalation exposures resulting from liquid pour for preservation
of textiles:  MOE = 14.

ST/IT inhalation exposure resulting from applying paint via
brush/roller:  MOE = 25.

	 

	6.3	Occupational Post-application Exposures tc \l2 "6.3	Occupational
Post-application Exposures 

	No occupational post-application exposures are assumed to occur for the
scenarios summarized in Table 6.1; any post-application exposures from
these uses are expected to occur in a residential setting.  These
exposure scenarios are assessed in the residential exposure assessment
in Section 4.

	6.4	Metalworking Fluids:  Machinist tc \l2 "6.4	Metalworking Fluids: 
Machinist 

	There is the 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 metalworking fluid and
a machinist is using/handling this treated end-product.

Dermal Exposure

Exposure Calculations 

	Short-term exposures – Short-term exposures for machinists were
assumed to pose potential risks due to dermal irritation.  Short-term
exposure estimates based on surface area were derived using the
following equation: 

	PE = % ai x FT

	         			

where: 

PE		=	Potential exposure (mg/cm2)

% ai	=	Fraction active ingredient in treated metalworking fluid
(unitless)

FT		=	Film thickness of paint on hands (mg/cm2)

	Intermediate-term exposures - There is also the potential for
intermediate-term exposures for a machinist that regularly comes in
contact with metalwork fluids treated with OIT, potentially leading to
systemic effects.  To determine intermediate-term exposure to OIT for
this scenario, the following equation, based on the 2-hand immersion
model from ChemSTEER, was used.  The model is available at   HYPERLINK
"http://www.epa.gov/opptintr/exposure/docs/chemsteer.htm" 
www.epa.gov/opptintr/exposure/docs/chemsteer.htm .  The 2-hand immersion
equation is as follows: 

PDR = SA x % ai x FT x FQ

	          BW			

where: 

PDR	=	Potential dose rate (mg/kg/day);

SA		=	Surface area of both hands (cm2/event);

% 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)

Assumptions

The percent active ingredient in the treated fluid was assumed to be the
highest use rate for metalworking use scenarios (75 ppm, or 0.0075%,
a.i. in treated metalworking fluid; Reg. No. 67071-6). 

It was assumed that exposure to a machinist’s hands would occur in the
absence of gloves.

For short-term duration exposures, the film thickness on the hands was
assumed to be 10.3 mg/cm2 (US EPA 1992).  This film thickness is based
on a machinist completing a double dip in which both hands are immersed
and remain wet.  The film thickness was chosen because the dermal
endpoint for short-term durations is based on dermal irritation effects
and represents an estimate in the absence of more specific data

For the intermediate-term duration, the film thickness on the hands is
1.75 mg/cm2 (US EPA 1992).  This film thickness is based on 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 the intermediate-term duration is based on systemic
effects.

For the intermediate-term exposure, the surface of area of both hands is
840 cm2/event (US EPA 1997b) and the body weight of an adult is 70 kg
(US EPA 1997b).

Results

	Table 6.3 shows the calculation of the dermal doses and dermal MOEs for
a machinist working with metal fluids. The MOE values are above the
target MOEs (10 for ST and 100 for IT) and therefore not a concern.

Table 6.3.  Short- and Intermediate-term Dermal Exposures and MOEs for
Machinist Exposure to Metalworking Fluids



Exposure Scenario	

% ai	

Hand Surface Area (cm2/event)	

Film thickness (mg/cm2)	

Frequency (event/ day)	Exposure a	

Dermal MOE (Target MOE is 10 for ST and  100 for IT) b

Machinist - two hand immersion	0.0075%	N/A	10.3 for ST	N/A	7.7E-4 mg/cm2
87



840	1.75 for IT	1	0.0016 mg/kg/day	3,800

a	For ST, exposures are calculated as a.i. per area of skin exposed
(mg/cm2) =  (% active ingredient x film thickness mg/cm2 (10.3 for ST
exposure).  For IT, exposures are calculated as an Absorbed Daily Dose
normalized to body weight (mg/kg/day) = [(% active ingredient x hand
surface area (cm2/event) x film thickness (mg/cm2) × Frequency
(event/day)] / Body weight (70 kg).

b	MOE = NOAEL (mg/kg/day) / exposure, where exposure is a.i./ skin area
(mg/cm2) for ST and Absorbed Daily Dose (mg/kg/day) for IT.  [Where:
short-term NOAEL = 0.0674 mg/cm2 and intermediate-term NOAEL = 5.95
mg/kg/day for dermal exposures, Table 3.2.] 

Inhalation Exposures

	The screening-level short- and intermediate-term inhalation exposure
estimate for treated metalworking fluids have been developed using the
OSHA PEL for oil mist.  The equation used for calculating the inhalation
exposure is:

PDR = PEL x % a.i.

where:

PDR		=	Potential dose rate (mg/m3);

PEL		=	OSHA PEL (mg/m3);

% a.i.		=	Fraction active ingredient in treated metalworking fluid
(unitless)

Assumptions  

		

The high-end oil mist concentration is based on OSHA’s Permissible
Exposure Limit (PEL) of 5 mg/m3 (NIOSH, 1998).

The percent active ingredient in the treated fluid was assumed to be the
highest use rate for metalworking use scenarios (75 ppm, or 0.0075%,
a.i. in treated metalworking fluid; Reg. No. 67071-6). 

Results

	Table 6.4 shows the calculation of the ST and IT inhalation exposures
and MOEs for a machinist working with metalworking fluids.  The
inhalation MOE values for ST and IT exposures to OIT are above the
target MOE of 30 and therefore not a concern.

Table 6.4.  Short- and Intermediate-term Inhalation Exposures and MOEs
Associated with Postapplication Exposure to Metalworking Fluids treated
with OIT (Machinist)

Exposure Scenario	% a.i.	OSHA PEL (mg/m3)	ST/IT Daily Exposurea (mg/m3)
ST/IT Inhalation MOE (Target MOE = 30) b

Machinist	0.0075%	5	0.000375	200

a 	Daily exposure or air concentration (mg/m3) = % active ingredient x
OSHA PEL (mg/m3).

b	MOE = 8 hr HEC (0.073 mg/m3) / air concentration (mg/m3)

	6.5   Professional Painter	

	6.5.1	Professional Painter - Short-term Dermal Exposure (Irritation) 
tc \l2 "6.5	Professional Painter - Short-term Dermal Exposure
(Irritation) 

	In this section, the potential for ST dermal exposure during
professional painting activities to OIT resulting in dermal irritation
is assessed.  IT exposures were not assessed for the professional
painter because it was assumed that not all of the paint used by a
professional on an intermediate-term basis is treated with OIT.

	The short-term exposure estimate based on surface area (i.e., as mg
a.i. per cm2 of skin area exposed) is derived using the approach
presented previously in Section 4.4.1 for the residential painter. 
Because the inputs for the professional painter are identical to those
used for the residential painter, the estimated exposure and MOE for
brush/roller and airless spray applicators are also the same (see Table
4.3).  There is not a concern with short-term dermal exposure because
the calculated MOE is10 (target MOE = 10).

	6.5.2  Professional Painter – Airless Sprayer Inhalation Exposure

	Table 6.2 presents the ST inhalation exposures and MOEs for application
of OIT preservative to the paint via brush/roller methods.  In this
section, the potential for ST inhalation exposures for professional
painters using an airless sprayer is assessed.  

Unit Exposure: For the airless sprayer scenario, the PHED inhalation
unit exposure value for a residential handler applying a pesticide using
an airless sprayer was used.  The test subjects were staining the
outside of a house with an airless sprayer.  Although these exposures
may differ slightly from exposures of painters of OIT persevered
products, these data are judged to be adequately representative.  The
inhalation unit exposure value for the airless sprayer application was
available in terms of an air concentration (mg/m3/% a.i.) as well as, in
terms of amount handled (mg/lb a.i.).  Since the inhalation toxicity
endpoint was determined from an inhalation study (as opposed to an oral
study), the endpoint units are given in terms of an air concentration
(mg/m3).  Therefore, in order to estimate inhalation risks (MOEs), it
was appropriate to use the unit exposure value in terms of an air
concentration (mg/m3/% a.i.) rather than amount handled (mg/lb a.i.). 
The inhalation unit exposure value of 0.68 mg/m3/% a.i was used for
baseline (i.e., no respirator) exposures.

Additionally, the OIT Task Force provided another exposure study to
supplement the existing PHED data.  The purpose of this study, conducted
by the National Paints and Coatings Association (NPCA) (Reinhardt and
Fendick, 2000), was to estimate exposure to crystalline silica while
spray painting or sanding three different formulations of latex paint in
an indoor environment. Although the study was conducted to specifically
evaluate crystalline silica exposure, respirable aerosol paint
concentrations were measured during airless spraying activities.  Each
of the three paint formulations was applied by a professional painter on
three consecutive days resulting in nine samples of respirable aerosol
paint concentrations.  The test worker painted the walls and ceilings of
rooms measuring 8 feet high, 10 feet wide, and 12 feet long.  A daily
painting exposure test (i.e., 8 hour work day) required painting five to
eight standard rooms while each room took 17 – 34 minutes to complete.
 The results showed that the average respirable aerosol breathing zone
concentration during airless spraying of paint was 3.67 mg/m3. The NPCA
study suggested that the respirable aerosol mass in the breathing zone
was no more than 16% of the total mass measured.  Therefore, because the
endpoint was based on nasal irritation, the respirable aerosol paint
concentration of 3.67 mg/m3 was adjusted up by 16% to estimate the
inhalable aerosol paint concentration (i.e., air concentration up to 100
microns) of 22.91 mg/m3.  These data were used to further characterize
the airless sprayer inhalation exposure even though the following were
identified as uncertainties or limitations in the NCPA study:

The study did not provide raw data to support the statement that the
respirable aerosol mass in the breathing zone was no more than 16% of
the total mass measured; 

The particle sizes were not actually measured;

No cut point was provided for the size of respirable or inhalable
aerosols.

Based on these limitations, an additional study is needed to determine
aerosol size distribution that is less than 100 microns.  Furthermore,
there is insufficient information on the distribution on the aerosol
size/diameter from the PHED data using the 2L/min sampling pump with
sampling cassettes facing downwards to adjust total aerosols to
inhalable particle size (i.e., 100 microns). Without this data, the air
concentration estimates using the PHED data can not be adjusted down to
estimate only inhalable aerosol concentrations, as suggested by the OIT
Task Force.

Exposure time:  It was assumed that it could take professional
applicators 6 hours to apply paint using an airless sprayer.   

Results

	Table 6.5 presents the calculations of the inhalation MOE for a
professional painter working with OIT treated paint.  The short-term
inhalation MOEs estimated for use of an airless sprayer are well below
the target MOE of 30 and therefore a concern.

Table 6.5.  Short-term Inhalation Exposures and MOEs for Professional
Painter Using an Airless Sprayer

Method of Application	App.Rate 

(% a.i.)	Inhalation Unit Exposure

PHED (mg/m3/%ai)

NCPA (mg/m3)	Air Conc.

(mg/m3)a	HEC

(mg/m3)	Route Specific 

MOE (ST) b

Airless Sprayer (PHED)	0.23% 	  SEQ CHAPTER \h \r 1 0.681	0.16	0.10 at 6
hrs	1

Airless Sprayer (NCPA)	0.23%	22.91	0.053	0.10 at 6 hrs	2

A Air con (mg/m3) = App Rate (%ai) x UE (mg/m3/%ai)  

(Note that the %ai in the PHED UE is in terms of whole numbers, not
fraction (i.e., 0.23 not 0.0023)

Air con (mg/m3) = App Rate (%ai) x UE (mg/m3i)  

(Note that the %ai using the NCPA UE is in terms of fraction (i.e.,
0.0023)

b Inhalation MOE = HEC (mg/m3) / Air conc. (mg/m3).  Target inhalation
MOE is 30.

	6.6	Leather Processing tc \l2 "6.6	Leather Processing 

	OIT can be used “...in the prevention of mold, bacteria, and fungi in
the storage and transport of wet leather stock such as pickled,
chrome-tanned, and vegetable-tanned leather” (EPA Reg. No. 707-121). 
The product, Kathon LM, contains 5.5% OIT and has a product density of
8.6 lbs per gallon (0.47 lbs ai/gallon).  The label specifies PPE (e.g.,
goggles or face shield and rubber gloves).  The label states that Kathon
LM should be used at a rate of 1,170 to 3,530 ppm (64 to 194 ppm a.i.)
based on wet hide weight depending on storage conditions and the length
of protection required.  

	The potential for occupational exposure was based on the loading of the
product by open pouring or connecting/disconnecting the metering pump. 
Chemical-specific exposure data were not submitted to support leather
processing.  Therefore, a screening-level assessment was developed using
surrogate data to determine the potential risks associated with leather
processing.  Although EPA does not have a specific surrogate exposure
scenario for pouring or metering antimicrobials into raceways, mixers,
or tanning drums, similar exposure data for loading products are
available.  The maximum amount of product handled during open pouring
was assumed to be 5 gallons (i.e., 2.36 lbs a.i. = 5 gal/day x 8.6
lb/gal product x 5.5% ai).  Because the labeled use rates are based on
the weight of the hides, it was assumed that the amount of product
potentially handled during metered pump activities would depend only on
the weight hides being processed (not the combined weight of the amount
of brine solution or salt used and the weight of the hides), which was
estimated based on standard EPA OPP/AD assumptions as follows.  

Raceways – Raceways are primarily used by hide processors to
facilitate the brine curing of raw hides; they are not typically found
in tanneries.    SEQ CHAPTER \h \r 1 The high end label rate of Kathon
LM used in raceways is 3,530 ppm.  High end treatment in raceways is
~1,000 hides per day; 300 hides treated per day is typical (each hide
weighs ~65 lbs).  Therefore, the high-end label concentration of 3,530
ppm requires that 12.6 lbs a.i. are handled daily during metered pump
operation, which was derived from (1,000 hides x 65 lbs/hide) x 0.000194
(i.e., 3,530 ppm x 5.5% ai in product).  This value was used for the
short-term (ST) assessment.  The typical amount of ai handled for
treating 300 hides per day (assuming the same rate of 3,530 ppm) was 3.8
lbs ai per day which was used for the intermediate- term (IT) inhalation
exposure assessment. 

Mixers - During leather processing, approximately 200 hides are treated
in a mixer per day (each hide weighs ~65 lbs).  The 200 hides treated
per day is assumed to represent the high end as well as typical
treatment.  The mixer uses salt in the treatment without water, and ~500
lbs of salt is used.  Therefore, the high end label concentration of
3,530 ppm requires that 2.62 lbs a.i. are handled daily during metered
pump operation, which was derived from [(500 lbs salt) + (200 hides x 65
lbs/hide)] x 0.000194 (i.e., 3,530 ppm x 5.5% ai in product).  

Tanning Drum - During leather processing, 400 hides are soaked in a
tanning drum (each hide weighs ~65 lbs).  The 400 hides treated per day
is assumed to represent the high end as well as typical treatment. 
Therefore, the high end label concentration of 3,530 ppm requires that
5.0 lbs a.i. are handled daily, which was derived from (400 hides x 65
lbs/hide)] x 0.000194 (i.e., 3,530 ppm x 5.5% ai in product).  

	The most representative exposure data available for industrial uses are
the monitoring data from the CMA Antimicrobial Exposure Assessment Study
(US EPA 1999: DP Barcode D247642).  The liquid open pour and liquid pump
data from the preservative loading were used to develop the
screening-level assessment.  The dermal UEs of 0.135 mg/lb a.i. for
liquid open pour and 0.00629 mg/lb a.i. for liquid pump are both based
on only 2 replicates where the test subjects were wearing a single layer
of clothing and chemical resistant gloves (UE are not available for the
“no glove” scenarios).  The inhalation UEs are based on the same 2
replicates.  The inhalation UE for open pour is 0.00346 mg/lb a.i. and
the UE for liquid pump is 0.000403 mg/lb a.i.  Although these exposure
scenarios are based on minimal replicates, the exposure values are
similar to those found in PHED for similar scenarios.

  SEQ CHAPTER \h \r 1 	Table 6.6 presents the potential non-cancer
dermal and inhalation risks for the leather processing use of OIT.  None
of the dermal and inhalation handler MOEs are of concern.  

Table 6.6.  Short and Intermediate-term Dermal and Inhalation Risks
Associated With Occupational Handling of OIT in Leatherworking

Equipment	Exposure Scenario	Unit Exposures

(mg/ lb a.i.)	Amount Handled

(lbs a.i./day)	Daily Dose

(mg/kg/day)	MOE d



Dermal	Inhal.

 IT Dermal a	ST/IT Inhal Dose b	ST/IT Inhal Air Conc.c	IT Dermal

Target MOE= 100	ST/IT Inhalation

Target MOE= 30

Raceway	Open pour – liquid	  SEQ CHAPTER \h \r 1 0.135	  SEQ CHAPTER
\h \r 1 0.00346	2.36	0.0046	1.2E-04	0.0010	1,300	72

	Metering pump	0.00629	0.000403	12.6 (ST) 

3.8 (IT)	0.00034	7.3E-05 (ST) 

2.2E-05 (IT)	0.00064 (ST)

0.00019 (IT)	17,000	120 (ST) 

380 (IT)

Mixer	Open pour – liquid	  SEQ CHAPTER \h \r 1 0.135	0.00346	2.36
0.0046	1.2E-04	0.0010	1,300	72

	Metering pump	0.00629	0.000403	2.62	2.3E-04	1.5E-05	0.00013	25,000	560

Tanning drum	Open pour – liquid	  SEQ CHAPTER \h \r 1 0.135	0.00346
2.36	0.0046	1.2E-04	0.0010	1,300	72

	Metering pump	0.00629	0.000403	5.0	4.5E-04	2.9E-05	0.00025	13,000	290

  SEQ CHAPTER \h \r 1 a	Dermal Dose (mg/kg/day) = Dermal UE (mg/lb ai) x
amount handled (lb ai/day) / 70kg .

b	Inhalation Dose (mg/kg/day) = Inhalation UE (mg/lb ai) x amount
handled (lb ai/day) / 70kg .

c	Air conc (mg/m3) = Inhal dose (mg/kg/day) x 70 kg x Inhal rate (day
/8m3)

d	MOE = NOAEL / Dose.  Where IT dermal NOAEL = 5.95 mg/kg/day, and ST
and IT inhalation HEC = 0.073 mg/m3. 

	6.7	Data Limitations/Uncertainties tc \l2 "6.8	Data
Limitations/Uncertainties 

	There are several data limitations and uncertainties associated with
the occupational handler exposure assessments which include the
following:

Surrogate dermal and inhalation unit exposure values were taken from the
proprietary CMA antimicrobial exposure study (US EPA 1999: DP Barcode
D247642) or from the Pesticide Handler Exposure Database (US EPA 1998).
Most of the CMA data are of poor quality therefore, AD requests that
confirmatory monitoring data be generated to support the values used in
these assessments.  

The quantities handled/treated were estimated based on standard AD
assumptions that can be further refined from input from registrants. 

The dermal exposure estimate for the occupational painter scenario using
treated paint was based on wet film thickness data from a study where
the user’s hands were immersed twice in mineral oil; no information
specific to the wet film thickness of paint was identified.  The method
employed may result in an underestimate of dermal exposures to paint.
The assessment could be refined by using a dermal irritation study where
the test substance is paint.

7.0	REFERENCES tc \l1 "7.0	REFERENCES  

DiDonato and Hazelton. 1990.  14C-RH-893: Effect of Vehicle, Formulation
or Occlusion on Dermal Bioavailability in Male Guinea Pigs.  Rohm and
Haas. May 22, 1990.

  SEQ CHAPTER \h \r 1 HERA.  2003.  Human and Environmental Risk
Assessment, Guidance Document Methodology, April 22, 2002 (  HYPERLINK
"http://www.heraproject.com/files/Guidancedocument.pdf" 
http://www.heraproject.com/files/Guidancedocument.pdf ).

Reinhardt and Fendick. 2000.  Exposure to Crystalline Silica and
Estimation of the Associated Human Health Risks from Painting and
Sanding Interior Flat Latex Paint.  Prepared for National Paint &
Coatings Association, Inc. (NPCA).  September 11, 2000.

SIMetric.  2005.  Mass, Weight, Density, or Specific Gravity of Bulk
Materials.    HYPERLINK "http://www.simetric.co.uk/si_materials.htm" 
http://www.simetric.co.uk/si_materials.htm , last accessed January 2007.

U.S. Air Force (USAF).  2003.  Department of The Air Force -
Headquarters Air Force Civil Engineer Support Agency, April 16, 2003
memo with the subject "Engineering Technical Letter (ETL) 03-3: Air
Force Carpet Standard."

U.S. Environmental Protection Agency (US EPA).  1992.  A Laboratory
Method to Determine the Retention of Liquids on the Surface of Hands. 
Prepared by C. Cinalli, C. Carter, A. Clark, and D. Dixon, under EPA
Contract No. 68-02-4254.  EPA-747/R-92-003.  Exposure Evaluation
Division, Office of Pollution Prevention and Toxics.  September 1992.

U.S. Environmental Protection Agency (US EPA).  1997a.  Standard
Operating Procedures (SOPs) for Residential Exposure Assessments.  EPA
Office of Pesticide Programs(Human Health Effects Division (HED). 
December 18, 1997.

U.S. Environmental Protection Agency (US EPA).  1997b.  Exposure Factors
Handbook. Volume I-II.  Office of Research and Development.  Washington,
D.C.  EPA/600/P-95/002Fa.

U.S. Environmental Protection Agency (US EPA).  1998.  PHED Surrogate
Exposure Guide.  Estimates of Worker Exposure from the Pesticide Handler
Exposure Database Version 1.1.   Washington, DC:  U.S. Environmental
Protection Agency.

U.S. Environmental Protection Agency (US EPA).  1999.  Evaluation of
Chemical Manufacturers Association Antimicrobial Exposure Assessment
Study.  Memorandum from Siroos Mostaghimi, Ph.D., USEPA, to Julie
Fairfax.

U.S. Environmental Protection Agency (US EPA).  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.

 It should be noted that water system uses are only listed on MUP labels
which do not provide application or use rates.  Since there are no EUP
labels containing water system uses, these uses were not assessed.  The
MUP labels need to be updated to delete these uses or new EUP labels
need to be submitted and reviewed by the Agency.

 It should be noted that water system uses are only listed on MUP labels
which do not provide application or use rates.  Since there are no EUP
labels containing water system uses, these uses were not assessed.  The
MUP labels need to be updated to delete these uses or new EUP labels
need to be submitted and reviewed by the Agency.

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