Document ID: EPA-HQ-OPP-2004-0305-0030
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2006-03-22T05:00Z

PHMB
Occupational/
Residential
Exposure
Assessment
CASE
3122
PC
CODE
111801
February
3,
2005
Timothy
Leighton,
Ph.
D.

Cassi
Walls,
Ph.
D.

Office
of
Pesticide
Programs
Antimicrobials
Division
U.
S.
Environmental
Protection
Agency
1200
Pennsylvania
Avenue,
NW
Washington,
DC
20460
2
EXECUTIVE
SUMMARY
The
Occupational
and
Residential
Exposure
Chapter
of
the
poly(
hexamethylenebiguanide)

hydrochloride
(
PHMB)
Reregistration
Eligibility
Decision
(
RED)
addresses
potential
exposures
and
risks
to
humans
who
may
be
exposed
to
PHMB
in
"
occupational
settings"
and
the
general
population
in
residential
settings.
In
particular,
the
following
exposed
populations
have
been
identified:
(
1)
handlers
(
mixers,
loaders,
applicators)
of
PHMB
products;
and
(
2)
individuals
who
are
involved
in
post­
application
or
reentry
activities.
At
this
time,
EPA
does
not
have
available
chemical­
specific
handler
or
postapplication
exposure
studies
to
support
PHMB.
Therefore,
inhalation
and
dermal
exposures
were
addressed
for
occupational
populations
using
surrogate
data
from
the
Chemical
Manufacturers
Association
(
CMA),
the
Pesticide
Handlers
Exposure
Database
(
PHED),
and
several
studies
which
relate
to
the
use
patterns
of
PHMB.
Using
surrogate
unit
exposure
data,
application
rates
from
labels,
and
EPA
estimates
of
daily
amount
handled,
exposure
and
risks
to
handlers
and
post­
application
workers
were
assessed.

The
registrant
for
PHMB
has
indicated
that
~
95
percent
of
the
use
of
this
chemical
is
for
pools
and
spas
(
PHMB
SMART
Meeting).
However,
it
should
be
noted
that
there
are
many
registered
use
categories
for
this
chemical
in
addition
to
its
use
in
pools
and
spas.
The
handler
scenarios
considered
in
this
assessment
are
summarized
in
tabular
format
to
follow.
These
scenarios
were
selected
based
on
examination
of
product
labels
describing
uses
for
the
product.

PHMB
Handler
Scenarios
Category
Scenario
Material
Preservatives
Pouring
PHMB
industrial
preservative
into
vats
or
tanks
of
slurry
containing
leather
processing
fluids,
silicones,
adhesives,
mineral
slurries,
etc.

Food
Handling/
Storage
Establishments
Premises
and
Equipment
Pouring
PHMB
preservative
into
vats
or
tanks
for
tunnel
pasteurization.

Industrial
Processes
and
Water
Systems
Pouring
or
pumping
PHMB
preservative
into
vats
or
tanks
for
preservation
of
oil
well
injection
fluids,
mud
packer
solutions,
and
workover
solutions.

Swimming
Pools
Pouring
PHMB
biocide/
sanitizer/
algae
control
preservatives
into
pools
or
spas.

Residential
and
Public
Access
Premises
PHMB
is
used
as
a
disinfectant
to
spray,
mop
and
wipe
surfaces
throughout
the
kitchen,
bath
and
other
areas
of
the
house.
Category
Scenario
3
Medical
Premises
and
Equipment
PHMB
is
used
in
a
spray,
wipe
and
mop
to
sterilize
surfaces
as
a
hospital
cleaner
disinfectant
and
medical
equipment.
Disinfectants
are
applied
by
spray,
mopping
and
wiping.

Handlers
The
exposure
and
risk
assessments
were
conducted
using
labeled
rates
with
standard
useinformation
and
CMA
and/
or
PHED
unit­
exposure
data.
After
performing
the
exposure
assessment,
EPA
determined
that
the
greatest
potential
for
exposure
appears
to
be
the
dermal
scenarios
involving:
pour
liquid
for
drilling
muds
(
dermal
MOE
=
74
and
inhalation
MOE
=
370)
and
pour
liquid
for
workover
fluids
(
dermal
MOE
=
74
and
inhalation
MOE
=
370).
In
order
to
achieve
MOEs
above
the
target
level
(
i.
e.,
greater
than
100),
scenarios
involving
drilling
muds
and
workover
fluid
must
use
mitigation
measures
such
as
metering
pump
systems.
Calculated
MOEs
using
the
pump
liquid
scenario
are
greater
than
the
target
MOEs.
As
the
mitigation
measure
brings
the
inhalation
MOE
above
1,000
(
which
includes
the
additional
10x
route­
to­
route
extrapolation),
no
confirmatory
inhalation
toxicity
study
is
needed.
All
of
the
other
occupational
uses
of
PHMB
are
not
of
concern
using
open
pouring
techniques.

Among
the
residential
and
commercial
handlers,
use
of
PHMB
did
not
trigger
risks
of
concern
for
the
spray/
mop/
wipe
and
swimming
pool/
spa
applications.

Post­
application
Residential
post­
application
exposures
to
children
playing
on
treated
floors
and
swimming
in
treated
pools/
spas
(
adults
too)
are
considered
in
this
assessment.
MOEs
are
greater
than
the
target
MOE
(
100)
for
residential
post­
application
exposure
to
adults
and
children
in
swimming
pools,
child
hand­

tomouth
ingestion
after
crawling
on
mopped
floors,
and
dermal
exposure
to
children
playing
on
treated
floors
after
mopping.
4
1.0
BACKGROUND
Purpose
In
this
document,
which
is
for
use
in
EPA's
development
of
the
PHMB
Reregistration
Eligibility
Decision
Document
(
RED),
EPA
presents
the
results
of
its
review
of
the
potential
human
health
effects
of
occupational
and
residential
exposure
to
PHMB.

Criteria
for
Conducting
Exposure
Assessments
An
occupational
and/
or
residential
exposure
risk
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
PHMB,
both
criteria
are
met.

2.0
Summary
of
Toxicity
Concerns
Relating
to
Occupational
and
Residential
Exposures
Acute
Toxicology
Categories
The
toxicological
database
for
PHMB
is
adequate
and
will
support
re­
registration
eligibility.

Toxicity
categories
for
PHMB
are
shown
in
Table
1.

Table
1.
Acute
Toxicity
Categories
for
20%
PHMB
Test
Results
Toxicity
Category
Acute
Oral
Toxicity
LD50=
2,747
mg/
kg
III
Acute
Dermal
Toxicity
LD50
>
5.0
mg/
kg
III
Acute
Inhalation
Toxicity
None
­­

Primary
Eye
Irritation
Severe
Eye
Irritant
I
Primary
Dermal
Irritation
Severe
Dermal
Irritant
I
Dermal
Sensitization
Moderate
Sensitization
­­
5
Selection
of
Toxicological
Endpoints
The
PHMB
Hazard
Identification
Assessment
Review
Committee
(
HIARC)
report
(
dated
April
18,
2001)
indicates
that
there
are
toxicological
endpoints
for
PHMB
(
U.
S.
EPA,
2001a).
Table
2
summarizes
these
endpoints.

Table
2.
Toxicological
Endpoints
for
Assessing
Occupational
and
Residential
Exposures/
Risks
Exposure
Scenario
Dose
Used
in
Risk
Assessment,
UF
Special
FQPA
SF*
and
Level
of
Concern
for
Risk
Assessment
Study
and
Toxicological
Effects
Acute
Dietary
(
Females
13­
50
years
of
age)
NOAEL
=
20
mg/
kg/
day
UF
=
100
Acute
RfD
=
0.2
mg/
kg/
day
FQPA
SF
=
1
aPAD
=
acute
RfD
FQPA
SF
=
0.2
mg/
kg/
day
Rabbit
Developmental
Study
(
MRID
42865901)

LOAEL
=
40
mg/
kg/
day
based
on
reduced
number
of
litters
and
skeletal
abnormalities.

Acute
Dietary
(
General
population
including
infants
and
children)
No
Appropriate
single
dose
effects
was
identified
for
general
population
Chronic
Dietary
(
All
populations)
NOAEL=
20
mg/
kg/
day
UF
=
100
Chronic
RfD
=

0.2
mg/
kg/
day
FQPA
SF
=
1
cPAD
=

chronic
RfD
FQPA
SF
=
0.2
mg/
kg/
day
Rabbit
Developmental
Study
(
MRID
#:

42865901)

LOAEL
=
40
mg/
kg/
day
Based
on
the
increased
mortality,
reduced
food
consumption,
and
clinical
toxicity;

Mouse
Developmental
Study
(
Report
No.

CTL/
P/
335,
1977
(
cited
in
Report
No.

003810,
1978.
Section
C­
9))

LOAEL
=
40
mg/
kg/
day;

Based
on
reduced
body
weight
gain;
and
Rat
Developmental
Study
(
Report
No.

CTL/
P/
1262,
1976
(
cited
in
Report
No.

003810,
1978.
Section
C­
11))

LOAEL
=
50
mg/
kg/
day
Based
on
reduced
food
consumption.
Exposure
Scenario
Dose
Used
in
Risk
Assessment,
UF
Special
FQPA
SF*
and
Level
of
Concern
for
Risk
Assessment
Study
and
Toxicological
Effects
6
Short­
Term
Incidental
Oral
(
1­
30
days)
NOAEL=
20
mg/
kg/
day
UF
=
100
Residential
LOC
for
MOE
=

100
Occupational
=
NA
See
Chronic
RfD
Intermediate­
Term
Incidental
Oral
(
1­
6
months)
NOAEL=
20
mg/
kg/
day
UF
=
100
Residential
LOC
for
MOE
=

100
Occupational
=
NA
See
Chronic
RfD
Short­
Term,

Intermediate­
Term,

and
Long­
Term
Dermal
Exposure
Dermal
(
or
oral)
study
NOAEL=
150
mg/
kg/
day
UF
=
100
(
Relative
dermal
absorption
rate
=
100%)
Residential
LOC
for
MOE
=
100
Occupational
LOC
for
MOE
=
100
80­
Week
Dermal
Painting
Study
(
MRIDs
00066475
and
00104796)

LOAEL
=
750
mg/
kg/
day
based
on
decreased
body
weight
and
liver
tumors.

Short­
Term,

Intermediate­
Term,

and
Long­
Term
Inhalation
Exposure
An
appropriate
route­
specific
inhalation
study
is
not
available.
The
oral
endpoint
of
20
mg/
kg/
day
with
a
Target
MOE
of
100
(
10x
inter­
species
extrapolation,
10x
intra­
species
variation)
is
used.
An
additional
10x
route­
to­
route
extrapolation
is
used
to
determine
if
a
confirmatory
inhalation
toxicity
study
is
warranted.

Cancer
(
oral,
dermal)
The
HED
Cancer
Assessment
Review
Committee.
(
CARC)
classified
PHMB
as
"
Suggestive
Evidence
of
Carcinogenicity,
but
not
sufficient
to
Assess
Human
Carcinogenic
Potential"
by
the
oral
and
dermal
routes.

Quantification
of
human
cancer
risk
is
not
required.

UF
=
uncertainty
factor,
FQPA
SF
=
FQPA
safety
factor,
NOAEL
=
no
observed
adverse
effect
level,
LOAEL
=
lowest
observed
adverse
effect
level,
PAD
=
population
adjusted
dose
(
a
=
acute,
c
=
chronic)
RfD
=
reference
dose,
LOC
=
level
of
concern,
MOE
=
margin
of
exposure
Dermal
Absorption
A
dermal
absorption
factor
was
not
needed
because
the
dermal
toxicity
is
based
on
a
dermal
study.

3.0
Handler
Exposures
and
Risks
EPA
has
determined
that
there
exists
a
potential
for
exposure
to
mixers,
loaders,
applicators,
or
other
handlers
during
usual
use­
patterns
associated
with
PHMB.
There
are
potential
exposures
from
use
in
industrial
settings
as
well
as
commercial
and
residential
uses
of
products.
At
the
PHMB
SMART
Meeting,
the
registrant
indicated
that
~
95
percent
of
the
use
of
this
chemical
is
for
pools
and
spas.

However,
there
are
many
other
registered
use
categories
for
this
chemical
in
addition
to
its
use
in
pools
and
spas.
7
3.1
Occupational
Handlers
Based
on
the
use
patterns,
EPA
has
identified
PHMB
products
that
are
used
in
the
following
use
site
categories
(
USC):

°
Material
Preservatives;

°
Food
Handling/
Storage
Establishments
Premises
and
Equipment;

°
Industrial
Processes
and
Water
Systems;

°
Swimming
Pools;

°
Residential
and
Public
Access
Premises;
and
°
Medical
Premises
and
Equipment.

Table
3
provides
a
description
of
exposure
scenarios
for
the
general
categories
of
occupational
handlers
(
e.
g.,
open
pour
for
Material
Preservatives).

3.2
Residential
Handlers
Based
on
the
use
patterns,
EPA
has
identified
the
four
major
exposure
scenarios
for
residential
handlers
including:

°
Open
pouring
for
swimming
pools/
spas;

°
Spraying
(
aerosol
and/
or
trigger
pump
sprays)
disinfectants;

°
Mopping
with
disinfectants;
and
°
Wiping
with
disinfectants.

Table
3
provides
a
description
of
exposure
scenarios
for
the
general
categories
of
occupational
handlers
(
e.
g.,
spray/
mop/
wipe
for
Residential
and
Public
Access
Premises).
8
Table
3.
Exposure
Scenarios
for
Occupational
Handlers
Use
Site
Categories
Scenario
Descriptions
Data
Source
Material
Preservatives
Silicones
and
Aqueous
Industrial
Chemicals;
Leather
Processing
Preservation
of
Fresh
Animal
Hides
and
Skins;
Preservation
of
Cellulosic
Fibers
and
Textiles;
Aqueous
Based
Polymer
Latices;
Aqueous
Mineral
Slurries;
Aqueous
Based
Adhesives;

Industrial
Electrocoats;
and
Household
Consumer
Products
Scenario
encompasses
a
variety
of
uses,

including
preservatives
added
to
silicones
and
aqueous
industrial
chemicals,
leather
processing,
etc.
Exposure
occurs
when
pouring
or
pumping
using
metering
systems.
Exposure
occurs
either
via
loading
and
filling
of
bulk
tanks,
contact
with
pipes,
or
hoses
or
setup/
maintenance
of
the
automated
metering
system.
General
preservatives
are
added
to
a
mechanical
system
and
mixed
into
slurries
in
tanks
or
bins.
CMA
data
for
general
preservatives
for
pour
liquid
are
used
as
the
most
conservative
measure
of
upper
bound
exposure.*

(
CMA,
1992;
U.
S.
EPA
1999).

Food
Handling/
Storage
Establishments
Premises
and
Equipment
Tunnel
Pasteurization
Scenario
encompasses
use
of
antimicrobial
additive
in
the
preservation
waters
of
canned
and
bottled
food
and
drink.
Exposure
occurs
when
pouring
or
pumping
using
metering
systems
by
filling
of
bulk
tanks,
contact
with
pipes,
or
hoses
or
setup/
maintenance
of
the
automated
metering
system.
CMA
data
for
general
preservatives
for
pour
liquid
are
used
as
the
most
conservative
measure
of
upper
bound
exposure.*

(
CMA,
1992;
U.
S.
EPA
1999).

Industrial
Processes
and
Water
Systems
Oil
Well
Injection
Systems
Drilling
Muds,
and
Workover
Fluids
Drilling
muds
and
preservatives
are
used
to
prevent
microbial
degradation
of
the
starch
component
of
fresh
water
drilling
fluids
and
to
stop
the
toxic
corrosive
hydrogen
sulfide
production.
The
primary
function
of
a
workover
fluid
is
to
control
formation
pressure,
transport
movable
solids
and
minimize
formation
damage.
Packaging
for
the
liquid
is
in
55­
gallon
drums
and
bulk
tanks
ranging
from
110
to
550
gallons.
The
products
are
poured
in
or
fed
by
chemical
pumps
specifically
designed
for
this
purpose.
CMA
data
for
general
preservatives
for
pour
liquid
and
pump
liquid
is
used
(
CMA,
1992;
U.
S.
EPA
1999).

Swimming
Pools
Pools
and
Spas
Spas
PHMB
can
be
used
as
a
chlorine­
free
biocide,
a
sanitizer,
and
for
control
of
algae
in
pools.
Exposure
occurs
when
pouring
or
pumping
using
metering
systems.
Exposure
occurs
either
via
pouring
or
pumping
using
automated
metering
systems.
CMA
data
for
general
preservatives
for
pour
liquid
are
used.*
(
CMA,
1992;
U.
S.
EPA
1999).

Residential
and
Public
Access
Premises
All
Purpose
Cleaner
PHMB
is
used
as
a
cleaner
in
residential
settings
via
sprays,
mopping,
and
wiping.
PHED
data
for
sprays
and
CMA
data
for
wiping/
mopping
(
CMA,
1992;
U.
S.
EPA
1999).

Medical
Premises
and
Equipment
Disinfectants
(
Sprays,
Mopping,
and
Wipes)
PHMB
is
used
in
a
wipe
to
sterilize
surfaces
and
medical
equipment.
Disinfectants
are
applied
by
spray,
mopping
and
wiping.
PHED
data
for
sprays
and
CMA
data
for
wiping/
mopping.
(
CMA,
1982,
U.
S.
EPA,
1999).

*
Pump
liquid
is
not
assessed
because
the
calculated
MOE
for
pouring
is
greater
than
the
target
MOE.
9
3.3
Handler
Data
and
Assumptions
In
the
course
of
development
of
this
Reregistration
Eligibility
Decision
document
(
RED),
limited
handler
exposure
data
were
available.
In
the
absence
of
PHMB
chemical­
specific
data,
surrogate
data
from
the
Chemical
Manufacturers
Association
(
CMA,
1992)
were
used
to
estimate
unit
exposure.
PHMB
labeling
information
along
with
EPA
estimates
were
used
to
determine
the
approximate
amount
handled
per
day.
These
data
were
used
to
predict
handler
exposures
for
the
various
scenarios.

Chemical
Manufacturers
Association
(
CMA)
Data
In
response
to
an
EPA
Data
Call­
In
Notice,
a
study
was
undertaken
by
the
Institute
of
Agricultural
Medicine
and
Occupational
Health
of
The
University
of
Iowa
under
contract
to
the
Chemical
Manufacturers
Association.
In
order
to
meet
the
requirements
of
Subdivision
U
of
the
Pesticide
Assessment
Guidelines
(
superseded
by
Series
875.1000­
875.1600
of
the
Pesticide
Assessment
Guidelines),
handler
exposure
data
are
required
from
the
chemical
manufacturer
specifically
registering
the
antimicrobial
pesticide.
The
applicator
exposure
study
must
comply
with
the
assessment
guidelines
for
"
Applicator
Exposure
Monitoring"
in
Subdivision
U
and
the
"
Occupational
and
Residential
Exposure
Test
Guidelines"
in
Series
875.
For
this
purpose,
CMA
submitted
a
study
on
28
February,
1990,
entitled
"
Antimicrobial
Exposure
Assessment
Study
(
amended
on
December
8,
1992)"
which
was
conducted
by
William
Popendorf,
et
al.
It
was
evaluated
and
accepted
by
Occupational
and
Residential
Exposure
Branch
(
OREB)
of
Health
Effect
Division
(
HED),
Office
of
Pesticides
Program
(
OPP)
of
EPA
in
1990.

The
purpose
of
this
CMA
study
was
to
characterize
exposure
to
antimicrobial
chemicals
in
order
to
support
pesticide
reregistrations
(
CMA,
1992).
The
unit
exposures
presented
in
the
most
recent
EPA
evaluation
of
the
CMA
database
(
U.
S.
EPA,
1999)
were
used
in
this
assessment.

The
Agency
determined
that
the
CMA
study
had
fulfilled
the
basic
requirements
of
Subdivision
U
­
Applicator
Exposure
Monitoring.
The
advantages
of
CMA
data
over
other
"
surrogate
data
sets"
is
that
the
chemicals
and
the
job
functions
of
mixer/
loader/
applicator
were
defined
based
on
common
application
methods
used
for
antimicrobial
pesticides.
A
few
of
the
deficiencies
in
the
CMA
data
are
noted
below:

°
The
inhalation
concentrations
were
typically
below
the
detection
limits,
so
the
unit
exposures
for
the
inhalation
exposure
route
could
not
be
accurately
calculated.

°
QA/
QC
problems
including
lack
of
field
fortification,
laboratory
recoveries,
and/
or
storage
stability
information.

°
Data
have
an
insufficient
amount
of
replicates.

The
Pesticide
Handlers
Exposure
Database
(
PHED)
10
The
Pesticide
Handlers
Exposure
Database
(
PHED)
has
been
developed
by
a
Task
Force
consisting
of
representatives
from
Health
Canada,
the
U.
S.
Environmental
Protection
Agency
(
EPA),
and
the
American
Crop
Protection
Association
(
ACPA).
PHED
provides
generic
pesticide
worker
(
i.
e.,

mixer/
loader
and
applicator)
exposure
estimates.
The
dermal
and
inhalation
exposure
estimates
generated
by
PHED
are
based
on
actual
field
monitoring
data,
which
are
reported
generically
(
i.
e.,
chemical
specific
names
not
reported)
in
PHED.
It
has
been
the
Agency's
policy
to
use
"
surrogate"
or
"
generic"
exposure
data
for
pesticide
applicators
in
certain
circumstances
because
it
is
believed
that
the
physical
parameters
(
e.
g.,
packaging
type)
or
application
technique
(
e.
g.,
aerosol
can),
not
the
chemical
properties
of
the
pesticide,
attribute
to
exposure
levels.
[
Note:
Vapor
pressures
for
the
chemicals
in
PHED
are
in
the
range
of
E­
5
to
E­
7
mmHg.]
Chemical­
specific
properties
are
accounted
for
by
correcting
the
exposure
data
for
study­
specific
field
and
laboratory
recovery
values
as
specified
by
the
PHED
grading
criteria.

PHED
handler
exposure
data
are
generally
provided
on
a
normalized
basis
for
use
in
exposure
assessments.
The
most
common
method
for
normalizing
exposure
is
by
pounds
of
active
ingredient
(
ai)

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

Estimated
Amount
Handled
Table
4
provides
the
assumptions
used
to
estimate
the
amount
of
PHMB
handled
per
day.
The
estimated
amounts
handled
per
day
were
used
in
conjunction
with
data
from
CMA
and
PHED
to
yield
exposure
estimates
for
handlers
in
various
scenarios.

It
should
be
noted
that
according
to
the
registrant
(
MRID
440513­
01)
PHMB
is
not
marketed
for
use
in
public
swimming
pools.
Instead,
PHMB
is
assessed
using
a
typical
residential
swimming
pool
capacity
of
20,000
gallons.
In
addition,
in
MRID
440513­
01,
the
registrant
estimates
that
the
upper­
end
of
the
range
for
amount
of
pools
that
a
pool
maintenance
worker
can
treat
in
one
day
is
20
pools.

However,
the
market
share
of
PHMB
in
residential
pools
is
not
believed
to
be
100
percent.
Therefore,

even
if
one
assumed
that
the
PHMB
market
share
for
treating
residential
pools
is
50
percent,
the
maximum
number
of
pools
treated
per
day
would
be
10
(
i.
e.,
10
pools/
day
x
20,000
gallons/
pool
=

200,000
gallons
treated
daily,
which
is
also
believed
to
be
representative
of
the
volume
of
a
typical
public
pool).

Table
4.
Exposure
Estimates/
Assumption
for
the
Daily
Amount
of
Preservative
Handled
Table
4.
Exposure
Estimates/
Assumption
for
the
Daily
Amount
of
Preservative
Handled
(
Continued)

11
Exposure
Scenarios
Pounds
Active
Ingredient
Used
Occupational
Handlers
(
1)
Open
Pour
Liquids
for
Material
Preservation
Scenario
encompasses
a
variety
of
uses
including
preservatives
added
to
silicones
and
aqueous
industrial
chemicals,
leather
processing,
etc.
Exposure
occurs
when
pouring
or
using
a
metering
system.
Exposure
occurs
either
via
loading
and
filling
of
bulk
tanks,
contact
with
pipes,
hoses,
or
setup/
maintenance
of
the
automated
metering
system.
General
preservatives
are
added
to
a
mechanical
system
and
mixed
into
slurries
in
tanks
or
bins.
PHMB
can
be
added
as
a
general
preservative
in
adhesives,
caulks,
coatings.
Assumes
10,000
pounds
of
slurry
(
e.
g.,
adhesives,
coatings,
emulsions,
etc)
are
treated
per
day.
Labels
indicate
the
following:
­
Silicones
and
Aqueous
Industrial
Products.
Dosage
is
listed
as
1
to
50
lb
Vantocil
®
per
10,000
lb
product.
Using
maximum
rate
(
50
lbs)
and
assuming
1,000
to
10,000
lb
of
product
treated,
the
total
amount
of
active
ingredient
(
20%
ai)
is
1
to
10
lb.
­
Leather
Processing.
Dosage
is
listed
as
1
to
30
lb
Vantocil
®
per
10,000
lb
product.
Using
the
maximum
rate
(
30
lb)
and
assuming
1,000
to
10,000
lb
of
product
treated,
the
total
amount
of
active
ingredient
(
20%
ai)
is
0.6
to
6
lb.
­
Aqueous
Based
Polymer
Latices.
Dosage
is
listed
as
5
to
50
lb
Vantocil
®
per
10,000
lb
product.
Using
the
maximum
rate
(
50
lb)
and
assuming
1,000
to
10,000
lb
of
product
treated,
the
total
amount
of
active
ingredient
(
20%
ai)
is
1
to
10
lb.
­
Animal
Skins
and
Hides.
Dosage
is
listed
as
1
to
2.6
lb
Vantocil
®
per
1,000
lb
of
hides.
Using
the
maximum
rate
(
2.6
lb)
and
assuming
1,000
to
10,000
lb
of
hides
treated,
the
total
amount
of
active
ingredient
(
20%
ai)
is
0.52
to
5.2
lb.
­
Cellulosic
Materials
and
Textiles.
Dosage
is
listed
as
0.025­
2%
based
on
the
dry
weight
of
the
product.
Using
the
maximum
rate
and
assuming
1,000
to
10,000
lb
of
product
treated,
the
total
amount
of
active
ingredient
(
20%
ai)
is
4
to
40
lb.
­
Aqueous
Mineral
Slurries.
Dosage
is
listed
as
5
to
50
lb
Vantocil
®
per
10,000
lb
product.
Using
the
maximum
rate
and
assuming
1,000
to
10,000
lb
of
product
treated,
the
total
amount
of
active
ingredient
(
20%
ai)
is
1
to
10
lb.
­
Aqueous
Based
Adhesives.
Dosage
is
listed
as
5
to
50
lb
Vantocil
®
per
10,000
lb
product.
Using
the
maximum
rate
and
assuming
1,000
to
10,000
lb
of
product
treated,
the
total
amount
of
active
ingredient
(
20%
ai)
is
1
to
10
lb.
­
Industrial
Electrocoats.
Dosage
is
listed
as
5
to
50
lb
Vantocil
®
per
10,000
lb
product.
Using
the
maximum
rate
and
assuming
1,000
to
10,000
lb
of
product
treated,
the
total
amount
of
active
ingredient
(
20%
ai)
is
1
to
10
lb.
­
Household
Consumer
Products.
Dosage
is
listed
as
2.5
to
25
lb
Vantocil
®
per
10,000
lb
product
(
250­
2,500
ppm).
Using
the
maximum
rate
and
assuming
1,000
to
10,000
lb
of
product
treated,
the
total
amount
of
active
ingredient
(
20%
ai)
is
0.5
to
5
lb.

(
2)
Open
Pour
Liquids
for
Food
Handling/
Storage
Equipment
Premises
Biocides
are
added
to
preserve
the
water
used
in
tunnel
pasteurization
and
tunnel
cooling
of
sealed
packages
of
canned
and
bottled
foodstuffs.
The
Agency
typically
assumes
1000
to
10,000
(
3,785­
37,850
liters)
gallons
of
tunnel
pasteurization
water
are
produced
per
day.
Labels
indicate
that
100­
1000
ppm
active
ingredient
are
added
in
the
diluted
fluid.
Using
the
maximum
dose
rate
on
the
label,
approximately
3,785
to
37,850
grams
of
ai
are
used
per
day
(
8.34­
83.4
lb
ai
per
day).
Exposure
Scenarios
Pounds
Active
Ingredient
Used
12
(
3)
Open
Pour
Liquids
and
Pump
Liquids
for
Industrial
Processes
and
Water
Systems
Biocides
are
added
to
preserve
oil
well
injection
water,
drilling
muds,
and
workover
fluids.
The
Agency
typically
assumes
1,000
barrels
(
42,000
gallons
or
158,987
liters)
handled
per
day
for
oil
well
injection
systems,
drilling
muds,
and
workover
fluids.
The
maximum
slug
treatment
to
oil
injection
waters
is
4
gallons
of
Vantocil
®
per
1,000
barrels
or
95
ppm.
Using
the
maximum
dose
on
the
label,
this
means
that
approximately
15,103
grams
of
ai
are
used
per
day
(
3.3
lb
ai
per
day).
For
drilling
muds
and
workover
fluids,
the
maximum
dose
on
the
label
is
126
gallons
of
Vantocil
®
per
1,000
barrels
or
3,000
ppm.
Using
the
maximum
dose
on
the
label,
approximately
476,961
grams
of
are
used
per
day
(
1,052
lb
ai
per
day).

Commercial
and
Residential
Handlers
(
1)
Open
Pour
Liquids
for
Swimming
Pools
(
Commercial
treaters)
Biocide
added
to
multiple
residential
pools
by
a
commercial
swimming
pool
company.
The
Agency
assumes
that
a
typical
residential
swimming
pools
capacity
is
20,000
gallons.
The
pool
is
treated
at
a
maximum
rate
of
50
ppm.
Using
the
maximum
dose
on
the
label,
approximately
1,000
grams
are
used
per
day
(
2.2
lb
ai
per
day).
For
commercial
treaters
of
residential
pools
(
i.
e.,
pool
company),
an
upper
bound
estimate
of
the
amount
of
PHMB
used
is
estimated
as
22
lb
ai
per
day
(
i.
e.,
10
residential
pools
treated
per
day).

(
2)
Open
Pour
Liquids
for
Swimming
Pools
(
Residential
pools)
Biocide
added
to
a
single
residential
pool
by
a
homeowner.
The
Agency
assumes
that
a
typical
swimming
pools
capacity
is
20,000
gallons.
The
pool
is
treated
at
a
maximum
rate
of
50
ppm.
Using
the
maximum
dose
on
the
label,
approximately
1,000
grams
are
used
per
day
(
2.2
lb
ai
per
day)
for
a
single
pool.

(
3)
Pump
Spray
Disinfectant
(
Residential
and
Medical
Premises)
PHMB
is
used
as
a
general
purpose
cleaner
(
e.
g
EPA
Reg
71661­
1).
EPA
Reg
71661­
1
indicates
a
concentration
of
0.56%.
It
is
assumed
that
1
liter
is
sprayed
per
day
for
the
medical
applications
and
that
the
product
has
a
density
of
1
gm/
mL.
Therefore
the
amount
handled
would
be
5.6
gm
ai
or
0.012
lb
ai
per
day.
For
the
residential
use,
it
is
assumed
that
the
maximum
used
would
be
0.5
liters
or
0.006
lb
ai/
day.

(
4)
Disinfectant
Mopping
(
Residential
and
Medical
Premises)
EPA
Reg.
71661­
1
indicates
a
concentration
of
0.56%
and
the
density
is
assumed
to
be
1
gm/
mL.
Assuming
that
2­
gallon
(
3.78
L)
mop
bucket
is
used
per
day
in
medical
premises,
the
amount
handled
would
be
21.2
gm
ai
or
0.047
lb
ai
per
day.
One
gallon
is
assumed
for
residential
uses
(
0.023
lb
ai/
day).

(
5)
Disinfectant
Wiping
(
Residential
and
Medical
Premises)
A
specific
label
for
the
wipes
was
not
used,
instead
it
is
assumed
that
the
application
rate
is
similar
to
that
of
EPA
Reg.
71661­
1.
Assuming
that
1
liter
is
used
per
day
in
medical
premises
for
wiping,
the
amount
handled
would
be
5.6
gm
ai
or
0.012
lb
ai
per
day.
½
liter
is
assumed
for
residential
uses
(
0.006
lb
ai/
day).

3.4
Handler
Risk
Assessment
and
Characterization
Exposure
estimates
for
occupational
handlers
are
presented
in
Table
5.
The
CMA
study
data
are
considered
to
be
the
most
appropriate
estimates
for
the
unit
exposures
associated
with
the
antimicrobial
uses
of
PHMB.
The
CMA
study
reports
two
risk
mitigation
methods
(
open
pouring
of
liquid/
solids
and
13
pump
metering
liquid).
These
two
risk
mitigation
methods
are
both
reported
in
Table
5.
This
assessment
traditionally
assumes
that
the
body
weight
of
adults
is
70
kg.
CMA
and
PHED
data
were
used
to
assess
dose
calculations.
PHED
estimates
are
limited
to
the
aerosol
can
spray.

Dermal
Daily
Dose
The
dermal
daily
dose
in
Tables
5
and
6
was
calculated
using
the
following
formula:

where:

Unit
Exposure
(
mg
ai/
lb
ai)
=
Values
obtained
from
CMA
(
CMA,
1992),
PHED
(
PHED,
1997),
or
Residential
SOPs
(
U.
S.
EPA,

1997a)

Use
Rate
=
Values
from
Table
4
Amount
Handled
(
lb/
day
or
gal/
day)
=
Values
from
Table
4
Body
weight
(
kg)
=
70
kg
14
Table
5.
Short­,
Intermediate­,
and
Long­
Term
Exposures
and
Risks
to
Occupational
Handlers
from
PHMB
Uses
Dermal
Exposurea
(
mg/
lb
ai)
Baseline
Inhalation
Unit
Exposurea
(
mg/
lb
ai)
App.
Rateb
(
lb
ai)
Dermal
c
Dermal
d
Inhalation
c
OCCUPATIONAL
Use
Site
Daily
Daily
Daily
Inhalation
d
Inhalation
Dermal
PRIMARY
USES
Category
Description
Exposure
Dose
Exposure
Daily
Dose
MOE
MOE
e
Application
Method
(
mg/
day)
(
mg/
kg/
day)
(
mg/
day)
(
mg/
kg/
day)

Material
Preservatives
Liquid
pour
Silicons
and
Aqueous
Industrial
Products
0.135
0.00361
1
0.135
0.00193
0.00361
0.0000516
390,000
77,700
0.135
0.00361
10
1.35
0.0193
0.0361
0.000516
39,000
7,770
Leather
Processing
0.135
0.00361
0.6
0.0810
0.00116
0.00217
0.0000310
650,000
129,000
0.135
0.00361
6
0.810
0.0116
0.0217
0.000310
65,000
12,900
Aqueous
Based
Polymer
Latices
0.135
0.00361
1
0.135
0.00193
0.00361
0.0000516
390,000
77,700
0.135
0.00361
10
1.35
0.0193
0.0361
0.000516
39,000
7,770
Animal
Skins
and
Hides
0.135
0.00361
0.52
0.0702
0.00100
0.00188
0.0000268
750,000
150,000
0.135
0.00361
5.20
0.702
0.0100
0.0188
0.000268
75,000
15,000
Cellulosic
Materials
and
Textiles
0.135
0.00361
4
0.54
0.00771
0.0144
0.000206
97,000
19,500
0.135
0.00361
40
5.40
0.0771
0.144
0.00206
9,700
1,950
Aqueous
Mineral
Slurries
0.135
0.00361
1
0.135
0.00193
0.00361
0.0000516
390,000
77,700
0.135
0.00361
10
1.35
0.0193
0.0361
0.000516
39,000
7,770
Aqueous
Based
Adhesives
0.135
0.00361
1
0.135
0.00193
0.00361
0.0000516
390,000
77,700
0.135
0.00361
10
1.35
0.0193
0.0361
0.000516
39,000
7,770
Industrial
Electrocoats
0.135
0.00361
1
0.135
0.00193
0.00361
0.0000516
390,000
77,700
0.135
0.00361
10
1.35
0.0193
0.0361
0.000516
39,000
7,770
Household
Consumer
Products
0.135
0.00361
0.5
0.0675
0.000964
0.00181
0.0000258
750,000
156,000
0.135
0.00361
5
0.675
0.00964
0.0181
0.000258
75,000
15,600
Food
Handling/
Storage
Premises
and
Equipment
Liquid
Pour
Tunnel
Pasteurization
0.135
0.00361
8.34
1.13
0.0161
0.0301
0.000430
47,000
9,320
0.135
0.00361
83.4
11.3
0.161
0.301
0.00430
4,700
932
Industrial
Processes
and
Water
Systems
Liquid
Pour
Oil
Injection
Waters
0.135
0.00361
3.3
0.446
0.00637
0.0119
0.000170
120,000
23,500
Drilling
Muds
0.135
0.00361
1052
142
2.03
3.80
0.0543
370
74
Workover
Fluids
0.135
0.00361
1052
142
2.03
3.80
0.0543
370
74
Liquid
Pump
Drilling
Muds
0.00629
0.000403
1052
6.62
0.0946
0.424
0.00606
3,300
1,590
Workover
Fluids
0.00629
0.000403
1052
6.62
0.0946
0.424
0.00606
3,300
1,590
a
Unit
exposures
based
on
CMA
data
for
inhalation
and
dermal
exposure.
Data
represent
single
layer
clothing
and
no
gloves.

b
Application
Rate
based
on
label
information
and
assumptions
on
daily
amounts
handled.

c
Dermal/
Inhalation
Exposure
(
mg/
day)=
Unit
Exposure
(
mg/
lb
ai)
*
Application
Rate
(
lb
ai).

d
Dermal/
Inhalation
Dose
(
mg/
kg/
day)=
Dermal
or
Inhalation
Exposure
(
mg/
day)/
Body
Weight
(
70
kg).

e
Dermal
MOE=
Dermal
NOAEL
(
150
mg/
kg/
day)/
Dermal
Dose
(
mg/
kg/
day).
Target
MOE
=
100.
15
Table
6.
Short­,
Intermediate­,
and
Long­
Term
Exposures
and
Risks
to
Residential
and
Commercial
Handlers
from
PHMB
Uses
RESIDENTIAL
HANDLERS/
SECONDARY
OCCUPATIONAL
USES
Dermal
Unit
Exposure
(
mg/
lb
ai)
Baseline
Inhalation
Unit
Exposure
(
mg/
lb
ai)
App.

Rate
(
lb
ai)
Dermal
Daily
Exposure
(
mg/
day)
Dermal
Daily
Dose
(
mg/
kg/
day)
Inhalation
Daily
Exposure
(
mg/
day)
Inhalation
Daily
Dose
(
mg/
kg/
day)
Dermal
MOE
Inhalation
MOE
Use
Site
Application
Method
Category
Description
Liquid
Pour
Swimming
Pools
(
commercial
treater)
0.135
0.00361
22
2.97
0.0424
0.0794
0.00113
3,535
18,000
Liquid
Pour
Swimming
Pools
(
residential)
0.135
0.00361
2.2
0.297
0.00424
0.00794
0.000113
35,000
180,000
Medical
Premises
and
Equipment
Spray
Disinfectant
(
Consumer
Product)
190
1.3
0.012
see
dose
0.033
see
dose
2.2E­
4
4,600
91,000
Mopping
Disinfectant
(
Consumer
Product)
71.6
2.38
0.047
see
dose
0.048
see
dose
0.0016
3,100
13,000
Wiping
Disinfectant
(
Consumer
Product)
2870
67.3
0.012
see
dose
0.492
see
dose
0.012
300
1,700
Residential
and
Public
Access
Spray
Disinfectant
(
Consumer
Product)
220
(
shorts)
1.3
0.006
see
dose
0.019
see
dose
1.1E­
4
8,000
180,000
Mopping
Disinfectant
(
Consumer
Product)
71.6
2.38
0.023
see
dose
0.024
see
dose
0.00078
6,400
26,000
Wiping
Disinfectant
(
Consumer
Product)
2870
67.3
0.006
see
dose
0.25
see
dose
0.0058
610
3,400
Footnotes:

a
Unit
exposures
based
on
PHED
and
CMA
data
for
inhalation
and
dermal
exposure.
Data
represent
single
layer
clothing
and
no
gloves
(
residential
spray
based
on
short­
pants
and
short­
sleeved
shirt
 
PHED
and
HED's
Residential
SOPs)
.

b
Application
Rate
based
on
label
information
and
assumptions
on
daily
amounts
handled.

c
Dermal/
Inhalation
Exposure
(
mg/
day)=
Unit
Exposure
(
mg/
lb
ai)
*
Application
Rate
(
lb
ai).

d
Dermal/
Inhalation
Dose
(
mg/
kg/
day)=
Dermal
or
Inhalation
Exposure
(
mg/
day)/
Body
Weight
(
70
kg).

e
Dermal
MOE=
Dermal
NOAEL
(
150
mg/
kg/
day)/
Dermal
Dose
(
mg/
kg/
day).
Target
MOE
=
100
16
Inhalation
Daily
Dose
Potential
daily
inhalation
dose
was
calculated
using
the
following
formula:

where:

Unit
Exposure
(
mg
ai/
lb
ai)
=
Values
obtained
from
CMA
(
CMA,
1992),

PHED
(
PHED,
1997),
or
Residential
SOPs
(
U.
S.
EPA,
1997a).

Use
Rate
(
lb
ai)
=
Values
from
Table
4
Amount
Handled
(
lb/
day
or
gal/
day)
=
Values
from
Table
4
Body
weight
(
kg)
=
70
kg
(
adults)

The
calculations
of
the
daily
dermal
and
inhalation
doses
of
PHMB
received
by
handlers
are
used
to
assess
the
dermal
risk
to
handlers.
The
MOEs
were
calculated
using
a
dermal
NOAEL
of
150
mg/
kg/
day
and
an
oral
NOAEL
of
20
mg/
kg/
day
for
inhalation
(
route­
to­
route
extrapolation).
The
following
formula
describes
the
calculation
of
an
MOE:

MOE
=
NOAEL
mg
kg
/
day
Daily
Dose
(
mg
/
kg
/
day)
 

 
 
 

 
 

Handler
Non­
Cancer
Risks
from
Dermal
and
Inhalation
Exposures
to
PHMB
For
PHMB,
a
MOE
greater
than
the
target
MOE
(
100)
is
an
indication
that
there
is
no
risk
concern
for
short­
term,
intermediate­
term,
and
chronic
exposures.

The
exposure
and
risk
assessments
were
conducted
using
the
maximum
use
rates
stated
on
the
labels
with
standard
use­
information
and
CMA
and/
or
PHED
unit
exposure
data.
After
performing
the
exposure
assessment,
EPA
determined
that
the
greatest
potential
for
exposures
appears
to
be
in
scenarios
involving:
pour
liquid
for
drilling
muds
(
dermal
MOE
=
74
and
inhalation
MOE
=
370);
and
pour
liquid
for
workover
fluids
(
dermal
MOE
=
74
and
inhalation
MOE
=
370).
In
order
to
achieve
MOEs
above
the
target
level
(
i.
e.,
dermal
greater
than
100),
scenarios
involving
drilling
muds
and
workover
fluid
must
use
17
mitigation
measures
such
as
using
metering
pump
systems.
Calculated
dermal
MOEs
using
the
pump
liquid
scenario
are
greater
than
the
target
MOE
(
i.
e.,
dermal
MOE=
1,600
and
inhalation
MOE
=
3,300).

As
the
mitigation
measure
brings
the
inhalation
MOE
above
1,000
(
which
includes
the
additional
10x
route­
to­
route
extrapolation),
no
confirmatory
inhalation
toxicity
study
is
needed.
MOEs
for
workers
in
medical
premises
using
PHMB
as
a
disinfectant
for
spraying,
mopping,
and
wiping
do
not
present
risks
of
concern
(
dermal
MOEs
=
4,600,
3,100,
and
300
while
inhalation
MOEs
=
91,000,
13,000,
and
1,700,

respectively).
MOEs
for
scenarios
involving
pouring
PHMB
liquid
into
swimming
pools
and
spas
for
a
commercial
treater
treating
10
residential
pools
per
day
are
greater
than
the
target
MOEs
(
dermal
MOE
=

3,500
and
inhalation
MOE
=
18,000).

The
calculations
of
short­,
intermediate­,
and
long­
term
inhalation
and
dermal
risk
for
residential
handlers
using
the
disinfectant
cleaners
indicate
no
risks
of
concern
(
for
dermal:
spraying
MOE
=
8,000,

mopping
MOE
=
6,400,
and
wiping
MOE
=
610;
and
for
inhalation
spraying
=
180,000,
mopping
MOE
=

26,000,
and
wiping
MOE
=
3,400).
Finally,
a
homeowner
pouring
PHMB
into
a
single
swimming
pool
does
not
pose
a
risk
of
concern
(
dermal
MOE=
35,000
and
inhalation
MOE
=
180,000).
All
calculated
MOEs
for
these
scenarios
were
greater
then
the
target
MOE.

4.0
Post­
Application
Assessment
In
the
course
of
development
of
this
exposure
chapter
for
the
Reregistration
Eligibility
Decision
(
RED),
limited
residential
exposure
data
were
available.
Most
of
the
information
provided
for
this
part
of
the
risk
assessment
were
provided
by
studies
performed
by
the
registrant.
These
studies
focus
largely
on
the
potential
of
increased
susceptibility
of
infants
and
children
from
exposure
to
PHMB,
as
required
by
the
Food
Quality
Protection
Act
(
1996).
FQPA
sets
an
explicit
standard
for
assessing
risks
from
potential
exposures
to
children.
EPA
must
determine
whether
exposures
to
pesticides
are
safe
for
children
and
includes
an
additional
safety
factor
for
children,
considering
special
sensitivities
and
exposures
to
pesticide
chemicals.
Specifically,
FQPA
requires
EPA
to
give
special
consideration
to
exposure
to
"
ensure
that
there
is
a
reasonable
certainty
that
no
harm
will
result
to
infants
and
children
from
aggregate
exposure
to
the
pesticide
chemical
residue."

Based
on
the
use
patterns,
EPA
has
identified
residential
post­
application
exposure
scenarios
for
the
swimming
pool/
spa
use
along
with
the
hard
surface
cleaners.
The
exposure
scenarios
that
are
considered
representative
of
the
high­
end
exposures
associated
with
PHMB
include:

°
Dermal
exposure
and
ingestion
of
PHMB
via
swimming
in
treated
pools
for
adults
and
children.

°
Dermal
contact
and
incidental
ingestion
(
i.
e.,
hand­
to­
mouth
residue
transfer)
resulting
from
toddlers
crawling
on
floors
after
mopping.
18
Descriptions
of
these
scenarios
are
presented
in
Table
7.

Table
7.
Residential
Exposure
Scenarios
Use
Site
Categories
Scenario
Descriptions
Data
Source
Swimming
Pools
Pools
are
treated
with
PHMB
(
biocide/
sanitizer/
control
growth
of
algae)
Adults
and
children
are
exposed
via
dermal
contact
to
swimming
pool
water
and
ingestion.
Risk
calculations
have
been
performed
for
both
competitive
swimmers
and
non­
competitive
swimmers.
SWIMODEL
3.0
Residential
and
Public
Access
Disinfectant
is
applied
on
counter
tops
and
floors
Toddlers
may
have
dermal
contact
with
floors
and
incidentally
ingest
disinfectants
after
mopping.
Residential
SOP
assumptions
Potential
occupational
post­
application
exposures
to
workers
using
liquid
pumps
for
drilling
muds
and
handling
workover
fluids
for
industrial
process
and
wastewater
systems
outdoors
are
expected
to
be
minimal.
Neither
of
these
activities
has
any
known
associated
post­
application
exposures.

4.1
Swimming
Pool
Use
4.1.1
Dermal
Exposure
to
PHMB
through
Swimming
Pool
Use
The
SWIMODEL
3.0
was
developed
by
EPA
as
a
screening
tool
to
conduct
exposure
assessments
of
pesticides
found
in
swimming
pools
and
spas.
The
SWIMODEL
uses
well­
accepted
screening
exposure
assessment
equations
to
calculate
the
total
worst­
case
exposure
for
swimmers
expressed
as
a
mass­
based
intake
value
(
mg/
event).
The
model
focuses
on
potential
chemical
intakes
only
and
does
not
take
into
account
metabolism
or
excretion
of
the
chemical
of
concern.
Detailed
information
and
the
downloadable
executable
file
are
available
at
http://
www.
epa.
gov/
oppad001/
swimodel.
htm.

Although,
the
actual
model
was
not
used
in
this
assessment,
the
same
equations
and
default
parameters
as
provided
in
the
SWIMODEL
User's
Manual
(
version
3.0)
were
used
in
a
spreadsheet
format
to
estimate
postapplication
dermal
and
incidental
oral
exposures.

The
following
equation
was
used
to
develop
dermal
doses:
19
where:

Dose
=
Daily
dose
for
pools,
(
mg/
kg/
day),

Cw
=
Chemical
concentration
in
pool
water
(
mg/
L),

Kp
=
Permeability
constant
(
cm/
hr),

SA
=
Surface
area
(
cm2),

ET
=
Exposure
time
(
hrs/
day),

CF
=
Conversion
factor
(
0.001
L/
cm3)

BW
=
Body
weight
(
kg).

The
Cw
and
Kp
parameters
are
chemical
specific
values
whereas,
the
remaining
parameters
are
based
on
the
default
values
provided
in
the
SWIMODEL
3.0.
The
PHMB
pool
water
concentration
of
10.4
mg/
L
is
based
on
information
provided
by
the
registrant
(
MRID
44051301)
and
the
permeability
constant
of
5x10­
6
cm/
hr
is
a
measured
value
also
determined
by
the
registrant
(
MRID
44046301).
It
should
be
noted
that
since
the
permeability
constant
provides
estimates
of
an
internal
dose
from
the
dermal
route
of
exposure,
the
oral
toxicity
endpoint
rather
than
the
dermal
toxicity
endpoint
is
used
to
assess
the
risks
from
the
dermal
swimming
route.
The
assumed
surface
area
presented
in
the
SWIMODEL
is
1.82
m2
for
adults,
1.42
m2
for
children
(
age
11­
14
years),
and
1.04
m2
for
children
(
age
7­
10
years).
The
assumed
body
weight
is
70
kg
for
adults,
48
kg
for
children
(
age
11­
14
years),
and
30
kg
for
children
(
age
7­
10
years).
Exposure
time
for
non­
competitive
swimmers
is
based
on
data
provided
in
EPA's
Exposure
Factors
Handbook
(
1997)
whereas
competitive
swimmer
exposure
time
data
are
based
on
the
Agency's
review
of
the
American
Chemistry
Council
(
ACC)
study
(
ACC,
2002).

It
should
be
noted
that
this
exposure
assessment
identifies
short­
term
(
1­
30
days)
and
intermediate­
term
(
1­
6
month)
noncancer
exposure
doses
based
on
the
reported
toxicology
endpoints
for
PHMB.
Because
of
the
shorter
exposure
durations
of
these
toxicological
endpoints,
conservative
eventbased
exposure
assumptions
are
used
to
calculate
upper
bound
daily
dose
estimates.
The
noncancer
doses
are
not
amortized
over
a
lifetime.
For
longer
term
chronic
and
cancer
doses,
exposure
times
and
frequencies
generated
by
ACC
will
likely
be
considered
and
adjusted
in
the
SWIMODEL
in
the
future.

The
dermal
doses
for
competitive
and
non­
competitive
adults,
children
7­
10
yrs,
and
children
11­

14
yrs
are
presented
in
Table
8.
The
parameters
used
to
calculate
the
dermal
exposure
are
also
included
in
this
table.
20
Table
8.
Parameters
for
Dermal
Swimming
Exposure
and
Dose
Estimate
Dermal
Adult
Adult
Child
(
7­
10
yrs)
Child
(
7­
10
yrs)
Child
(
11­
14
yrs)
Child
(
11­
14
yrs)

Type
of
Swimmer
Comp.
Non­

Comp.
Comp.
Non­

Comp.
Comp.
Non­

Comp.

Cw
(
mg/
L)
10.4
10.4
10.4
10.4
10.4
10.4
Kp
(
cm/
hr)
5E­
6
5E­
6
5E­
6
5E­
6
5E­
6
5E­
6
ET
(
hr/
day)
3
5
1
5
2
3
SA
(
cm2)
1.82E4
1.82E4
1.04E4
1.04E4
1.42E4
1.42E4
BW
(
kg)
70
70
30
30
48
48
CF
(
L/
cm3)
0.001
0.001
0.001
0.001
0.001
0.001
Dose
(
mg/
kg/
day)
4.06E­
5
6.76E­
5
1.80E­
5
9.01E­
5
3.08E­
5
4.62E­
5
The
dermal
swimming
route
is
assessed
using
the
oral
NOAEL
of
20
mg/
kg/
day
because
the
SWIMODEL
estimates
an
internal
dose
resulting
from
the
dermal
route.
The
target
MOE
is
100.
The
equation
for
calculating
the
MOE
based
on
the
dermal
route
of
exposure
is
presented
below:

Table
9
presents
the
estimated
dose
from
the
dermal
route
of
exposure
and
the
corresponding
MOEs
based
on
the
oral
endpoint
for
the
swimming
scenarios
for
each
age
group.
21
Table
9.
Dermal
Dose
and
MOE
for
Residential
Post­
Application
Swimming
Exposure
Use
Type
Scenario
Description
Dose
(
mg/
kg/
day)
Dermal
MOEa
Swimming
Pool
Adult
Competitive
4.06E­
5
490,000
Adult
Non­
Competitive
6.76E­
5
300,000
Child
(
7­
10
yrs)

Competitive
1.80E­
5
1,100,000
Child
(
7­
10
yrs)

Non­
Competitive
9.01E­
5
220,000
Child
(
11­
14
yrs)

Competitive
3.08E­
5
650,000
Child
(
11­
14
yrs)

Non­
Competitive
4.62E­
5
430,000
aMOE
=
NOAEL
(
mg/
kg/
day)/
Dose
(
mg/
kg/
day).
Dermal
dose
for
swimmers
is
an
internal
dose
based
on
the
SWIMODEL
results,
and
therefore,
the
oral
NOAEL
of
20
mg/
kg/
day
is
used.

Target
MOE
=
100
The
calculated
results
for
short­,
intermediate­,
and
long­
term
exposures
and
risks
indicate
that
the
risks
from
the
dermal
route
of
exposure
are
not
of
concern
(
MOE>
100)
for
the
post­
application
scenarios
developed
in
this
assessment.

4.1.2
Ingestion
of
PHMB
through
Swimming
Pool
Use
The
following
equation
was
used
to
develop
ingestion
doses:

where:

Dose
=
Daily
dose
for
pools,
(
mg/
kg/
day),

Cw
=
Chemical
concentration
in
pool
water
(
mg/
L),

IR
=
Ingestion
rate
of
pool
water
(
L/
hr),

ET
=
Exposure
time
(
hrs/
day),

BW
=
Body
weight
(
kg),
22
The
PHMB
concentration
in
pool
water
is
based
on
information
provided
by
the
registrant
(
MRID
440513­
01).
The
ingestion
rates
used
in
the
SWIMODEL
3.0
are
based
on
the
values
used
in
EPAs
Residential
SOPs
(
USEPA,
2000)
and
an
EPA
pilot
study
as
discussed
in
ACC's
swimmer
survey
(
ACC,

2002).
The
rest
of
the
assumptions
used
in
calculating
the
ingestion
dose
for
competitive
and
non
competitive
adults
and
children
(
7­
10
yrs
and
11­
14
yrs)
are
presented
in
Table
10
and
are
consistent
with
the
assumptions
used
in
the
dermal
assessment.

Table
10.
Parameters
for
Swimming
Ingestion
Exposure
and
Dose
Estimate
Age
Adult
Adult
Child
7­
10
yrs
Child
7­
10
yrs
Child
11­
14
yrs
Child
11­
14
yrs
Type
of
Swimmer
Comp.
Non­

Comp.
Comp.
Non­

Comp.
Comp.
Non­
Comp.

Cw
(
mg/
L)
10.4
10.4
10.4
10.4
10.4
10.4
IR
(
L/
hr)
0.0125
0.0125
0.05
0.05
0.025
0.05
ET(
hr/
day)
3
5
1
5
2
3
BW(
kg)
70
70
30
30
48
48
Dose
(
mg/
kg/
day)
0.0056
0.019
0.017
0.087
0.011
0.033
The
equation
for
calculating
the
oral
MOE
is
presented
below:

MOE
values
calculated
for
ingestion
of
PHMB
in
swimming
pool
water
are
presented
in
Table
11.
23
Table
11.
Ingestion
Dose
and
MOE
for
Residential
Swimming
Post­
Application
Use
Type
Scenario
Description
Dose
(
mg/
kg/
day)
Ingestion
MOE
a
Swimming
Pool
Adult,
Competitive
0.0056
3600
Adult,
Non­
Competitive
0.019
1100
Child
(
7­
10
yrs),
Competitive
0.017
1200
Child
(
7­
10
yrs),
Non­
Competitive
0.087
230
Child
(
11­
14
yrs),
Competitive
0.011
1800
Child
(
11­
14
yrs),
Non­
Competitive
0.033
620
aMOE
=
NOAEL
mg/
kg/
day/
Dose
(
mg/
kg/
day).
Oral
NOAEL
is
20
mg/
kg/
day.

Target
MOE
=
100
The
calculations
for
intermediate
incidental
ingestion
of
PHMB
indicate
no
risk
concern
for
the
non­
competitive
or
competitive
swimming
pool
scenarios
(
i.
e.,
MOE>
100).

4.2
General
Purpose
Cleaner
(
Floor
Treatments)

4.2.1
Dermal
Contact
From
Toddlers
Crawling
On
Floors
After
Mopping
There
is
the
potential
for
dermal
exposure
to
toddlers
crawling
on
treated
floors
after
mopping
with
PHMB.
To
determine
toddler
exposure
to
residues
on
treated
floors,
the
following
equation
was
used:

PDD
FR
x
SA
BW
=

where:

PDD
=
Potential
daily
dose
FR
=
Flux
rate
of
chemical
from
material
(
mg/
m2/
day)

SA
=
Surface
area
of
the
body
which
is
in
contact
with
the
floor
(
m2)

BW
=
Body
weight
(
kg)

The
following
conservative
assumptions
were
made
in
calculating
the
exposures/
risks
due
to
limited
data:
24
°
Toddlers
(
3
years
old)
are
used
to
represent
the
1
to
6
year
old
age
group
and
are
assumed
to
weigh
15
kg,
the
median
for
male
and
female
toddlers
(
USEPA,
2000b).
A
body
surface
area
of
0.657
m2
has
been
assumed,
which
is
the
median
value.

°
The
label
did
not
provide
information
on
the
volume
of
disinfectant
to
be
used
for
cleaning
surfaces
such
as
floors.
It
was
assumed
that
the
diluted
treatment
solution
is
applied
at
a
rate
of
1000
sq.
ft.
per
gallon.

°
No
data
could
be
found
regarding
the
quantity
of
solution/
residue
left
on
the
floor
after
treatment.
As
a
conservative
measure,
it
has
been
assumed
that
25%
of
the
mop
solution
remains
after
the
final
mop.

°
No
leaching
data
were
available
that
could
be
used
to
estimate
a
flux
rate
of
the
chemical
from
the
floor/
hard
surface.
Therefore,
the
Residential
SOPs
estimate
of
10%
of
the
amount
on
the
floor/
hard
surface
available
for
dermal
transfer
is
used.

According
to
label
information
(
EPA
Reg
71661­
1),
this
product
can
be
used
as
a
floor
cleaner
and
contains
0.56%
active
ingredient.
Assuming
that
1
gallon
of
solution
treats
1000
ft2
and
the
density
is
equivalent
to
water
(
1
g/
mL),
the
applied
amount
would
be
227
mg/
m2.
The
SOPs
assume
that
an
average
of
10%
of
the
application
rate
is
available
on
the
hard
surfaces
as
dislodgeable
residues.
Additionally,
it
was
assumed
that
25%
of
the
formulation
remains
on
the
hard
surface.
Therefore,
the
indoor
surface
residue
at
time
zero
would
be
5.68
mg/
m2.
The
SOPs
also
conservatively
assume
that
post­
application
exposure
occurs
immediately
after
application.

The
calculation
of
the
dermal
dose
and
the
dermal
MOE
are
shown
in
Table
14
.
The
dermal
MOE
calculated
is
above
the
target
MOE
of
100
and,
therefore,
not
of
concern.
25
Table
12.
Short­
and
Intermediate­
Term
Risks
Associated
with
Post­
Application
Dermal
Exposure
to
Disinfectant
on
Treated
Floors.

Parameter
Value
Rationale
Application
Rate
1gallon
of
solution/
1000
ft2
USEPA
Assumption
%
A.
I.
in
Formulated
Product
0.56%
Maximum
rate
listed
on
label
(
71661­
1)

Density
of
Cleaning
Solution
1.0
g/
mL
Assumed
to
be
similar
to
density
of
water
Flux
Rate
of
Chemical
from
Hard
Surface
Flooring
5.68
mg/
m2/
day
(
App.
Rate)
*(
Density)
*

(%
A.
I.)
*
(
25%
remaining)*

(
10%
transfer)
*
(
Conversion
Factors)

Surface
Area
of
Body
in
Contact
with
Hard
Surface
Flooring
0.657
m2
Median
surface
area
of
toddler
Body
Weight
15
kg
Median
body
weight
of
toddler
Potential
Dermal
Exposure
0.25
mg/
kg/
day
FR
*
SA
*
DA/
BW
Dermal
NOAEL
150
mg/
kg/
day
Dermal
MOE
600
(
Derm.
NOAEL)
/
(
Daily
Derm.
Dose).
Target
MOE
=
100.

4.2.2
Incidental
Ingestion
of
PHMB
Resulting
From
Floor
Treatments
(
Hand­
to­
Mouth)

In
addition
to
dermal
exposure,
infants
crawling
on
treated
floors
will
also
be
exposed
to
PHMB
via
incidental
oral
exposure.
To
calculate
incidental
ingestion
exposure
to
PHMB
due
to
hand­
to­
mouth
transfer,
the
scenarios
established
in
the
Standard
Operating
Procedures
(
SOPs)
for
Residential
Exposure
Assessments
were
used.
These
scenarios
use
assumptions
that
are
similar
to
those
used
in
calculating
exposures
due
to
dermal
contact
of
PHMB
from
toddlers
crawling
on
floors
after
mopping.

These
assumptions
level
to
an
estimate
of
0.565
:
g
PHMB/
cm2
being
available
for
dislodging
from
the
floor.
The
estimated
potential
dose
rate
immediately
after
application
would
be
calculated
as
follows:

PDRnorm=
ISRt
x
SA
x
FQ
x
SE
x
ET
x
0.001
mg/:
g
BW
where:
26
PDRnorm
=
Potential
dose
rate
(
mg/
kg/
day);

ISRt
=
Indoor
surface
residue
(:
g/
cm2)
at
time
0;

SA
=
Surface
area
of
the
hands
that
contact
both
the
treated
area,
and
the
individuals
mouth
(
cm2/
event);

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

SE
=
Saliva
extraction
efficiency
(
50%);

ET
=
Exposure
time
(
4
hrs/
day);
and
BW
=
Body
weight
(
15
kg)

The
surface
area
used
for
each
hand­
to­
mouth
event
is
20
cm2
.
It
is
assumed
that
there
are
20
hand­
to­
mouth
exposure
events
per
hour
(
90th
percentile)
for
the
short­
term
and
9.5
events/
hour
(
mean)
for
the
intermediate­
term
duration.
The
PDR
generated
in
this
assessment
is
an
acute
estimate
of
exposure
to
wet
surfaces
only.
In
order
to
calculate
the
short­
term
and
intermediate­
term
dermal
exposure
for
post­
application
dermal
exposures,
the
proposed
data
presented
by
the
Hazard
Identification
Assessment
Review
Committee
(
HIARC)
suggests
that
an
oral
NOAEL
of
20
mg/
kg/
day
should
be
used
as
the
toxicity
endpoint
for
both
short­
and
intermediate­
term
incidental
ingestion
exposures
(
U.
S.
EPA,
2001a).
The
calculation
of
the
potential
dose
rate
(
PDR)
is
0.031
mg/
kg/
day
for
the
short­
term
and
0.014
mg/
kg/
day
for
the
intermediate­
term
duration.
The
resulting
MOEs
for
toddlers
are
660
for
the
short­
term
and
1,400
for
the
intermediate­
term,
which
are
above
the
target
MOE
of
100.

5.0
Uncertainties
5.1
Occupational
Handler
Scenarios
Currently,
PHMB
chemical­
specific
handler
or
post­
application
exposure
studies
that
meet
Agency
guidelines
have
not
been
identified.
Surrogate
dermal
and
inhalation
data
from
the
Chemical
Manufacturers
Association
(
CMA)
database,
were
used
to
assess
handler
exposure.
Note
that
CMA
surrogate
data
have
the
following
deficiencies:

°
The
inhalation
concentrations
were
typically
below
the
detection
limits,
so
the
unit
exposures
for
the
inhalation
exposure
route
could
not
be
accurately
calculated.

°
The
quality
of
the
CMA
data
were
assessed
using
the
same
grading
criteria
as
PHED
and
the
grades
were
all
at
C,
D,
E,
lower
than
PHED
standards
(
e.
g.,
most
of
PHED
are
at
grades
A,
B,
C).

°
Grade
C,
D,
E
data
frequently
may
have
QA/
QC
problems
including
lack
of
field
fortification,
laboratory
recoveries,
and/
or
storage
stability
information.
27
°
Grade
C,
D,
E
data
have
an
insufficient
amount
of
replicates.

°
Grade
C,
D,
E
data
may
have
higher
variabilities
(
e.
g.,
high
CVs).

5.2
Post­
Application
Scenarios
Calculations
for
the
swimming
pool
scenarios
rely
on
the
use
of
SWIMODEL,
a
model
which
has
the
following
limitations:

°
SWIMODEL
focuses
on
potential
chemical
intakes
only.
It
does
not
account
for
metabolism
or
excretion
of
the
chemical
of
concern.

°
SWIMODEL
does
NOT
predict
or
calculate
chemical
concentration
values
in
exhaled
air
or
blood.
Therefore,
biological
monitoring
results
cannot
be
directly
compared
or
related
to
SWIMODEL
outputs.

°
SWIMODEL
uses
the
following
absorption
factors
for
each
route
of
exposure:

­
Ingestion:
100%
absorption
of
ingested
chemical
assumed
­
Dermal:
Uses
a
chemical­
specific
dermal
permeability
coefficient
°
Dermal
exposure
estimates
are
predicated
on
a
one
compartment
model
of
the
skin.
The
rate­
limiting
step
is
penetration
of
the
stratum
corneum.
The
model
uses
Fick's
Law
of
Diffusion
to
calculate
a
general
exposure
value,
without
regard
for
differences
in
the
skin
permeability
of
specific
body
parts.

6.0
REFERENCES
ACC.
2002.
American
Chemistry
Council
(
ACC).
An
Analysis
of
the
Training
Patterns
and
Practices
of
Competitive
Swimmers.
Prepared
by
Richard
Reiss.
Sciences
International,
Inc.
Alexandria,
Virginia.
December
19,
2002.

CMA.
1992.
Chemical
Manufacturers
Association
Antimicrobial
Exposure
Assessment
Study.
Popendorf,
W,
Selim,
M.,
Kross,
B.
The
University
of
Iowa.
MRID
425875­
01.
December
8,
1992.

IT
Environmental
Programs,
Inc.,
1991
Chemical
Engineering
Branch
Manual
for
the
Preparation
of
Engineering
Assessments.
Contract
No.
68­
D8­
0112.
Work
Assignment
P3­
7.
U.
S.
Environmental
Protection
Agency.
Office
of
Toxic
Substances.
February
28,
1991.

MRID
440463­
01.
14C­
Polyhexamethylene
Biguanide
(
PHMB):
Absorption
Through
Human
Epidermis
and
Rat
Skin
In
Vitro.
Sponsor
Facility:
Zeneca
Inc.
October
15,
1982.

MRID
440513­
01.
Assessment
of
Worker
and
Postapplication
Exposure
to
PHMB
Used
in
Pools
and
Spas.
Sponsor
Facility:
Zeneca
Specialties.
Subcontractor:
Jellinek,
Schwartz,
and
Connolly,
Inc.
June
27,
1996.
28
MRID
451877­
01.
A
Health
Risk
Assessment
for
PHMB
(
Vantocil
IB)
Used
on
100%
Cotton
Textile
Application­
Systemic
Toxicity
by
an
Infant
Sucking
Textile.
Sponsor
Facility:
Avecia,
Inc.
August
10,
2001.

PHED.
1997.
Surrogate
Exposure
Guide.
Estimates
of
Worker
Exposure
from
the
Pesticide
Handler
Exposure
Database
Version
1.1
May
1997.

U.
S.
EPA.
1997a.
Standard
Operating
Procedures
(
SOPs)
for
Residential
Exposure
Assessments.
Contract
No.
68­
W6­
0030.
Prepared
by
the
Residential
Exposure
Assessment
Work
Group.
Office
of
Pesticide
Programs,
Health
Effects
Division
and
Versar.
July
1997.

U.
S.
EPA.
1997b.
Exposure
Factors
Handbook.
National
Center
for
Environmental
Assessment,
Office
of
Research
and
Development.

U.
S.
EPA.
2000.
Standard
Operating
Procedures
(
SOPs)
for
Residential
Exposure
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