Document ID: EPA-HQ-OPP-2003-0250-0010
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2004-03-11T05:00Z

Occupational
Risk
Characterization
Date
completed:
Feb
18,
2004
Prepared
for:

Regulatory
Management
Branch
II
Antimicrobial
Division
Office
of
Pesticide
Programs
U.
S.
Environmental
Protection
Agency
Arlington,
VA
22202
Prepared
by:

Jonathan
Chen,
Ph.
D.
Risk
Assessment
and
Science
Branch
Antimicrobial
Division
Office
of
Pesticide
Programs
U.
S.
Environmental
Protection
Agency
Arlington,
VA
22202
TABLE
OF
CONTENTS
BACKGROUND
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1
1.0
HAZARD
ASSESSMENT
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1
1.1
Adequacy
of
the
Data
Base
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1
1.2
Hazard
Assessment
of
Inorganic
Arsenic
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2
1.3
Hazard
Assessment
of
Chromium
(
VI)
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5
1.4
FQPA
Consideration
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5
2.0
EXPOSURE
ASSESSMENT
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5
2.1
Identification
of
Potential
Receptor
Populations
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8
2.1.1
Primary
Occupational
Handlers
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2.1.2
Postapplication
Occupational
Receptors
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2.2
Identification
of
Potential
Exposure
Assumptions
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9
3.0
RISK
CHARACTERIZATION
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9
3.1
Non­
carcinogenic
Risk
Characterization
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10
3.2
Carcinogenic
Risk
Characterization
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10
3.2.1
Arsenic
Carcinogenic
Risk
Characterization
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10
3.2.2
Chromium
Carcinogenic
Risk
Characterization
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10
6.0
UNCERTAINTY
ANALYSIS
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19
6.1
Uncertainties
and
Deficiencies
in
Hazard
Assessment
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19
6.1.1
Using
Human
Data
Setting
the
Short­
term
and
Intermediate­
term
Incidental
Oral
and
Dermal
Exposures
End­
Points
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19
6.1.2
Dermal
Absorption
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19
6.1.3
Arsenic
Cancer
Potency
Factors
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20
6.2
Uncertainties
and
Deficiencies
in
Exposure
Assessment
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20
6.2.1
Data
Gaps
and
Limitations
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20
7.0
CONCLUSIONS
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20
7.1
Primary
Handler
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20
7.2
Postapplication
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21
8.0
REFERENCES
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22
LIST
OF
TABLES
Table
1.
Acute
Toxicity
Summary
of
Arsenic
Acid
(
75%)
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3
Table
2.
Toxicological
Endpoints
for
Assessing
Occupational
Exposures/
Risks
to
Arsenic
(
V)
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4
Table
3:
Acute
Toxicity
Summary
of
the
Chromium
(
VI)
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6
Table
4.
Toxicological
Endpoints
for
Assessing
Occupational
Exposures/
Risks
to
Chromium
(
VI)
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7
Table
5.
Risk
Characterization
of
Exposure
Assessment
to
Primary
Handler
Short­,
Intermediate­,
and
Long­
term
B
Non­
Cancer
Risks
to
CCA
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11
Table
6.
Risk
Characterization
of
Exposure
Assessment
to
Postapplication
­
Short­,
Intermediate­,
and
Long­
term
B
Non­
Cancer
Risks
to
CCA
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12
Table
7The
Cancer
Risks
Associated
with
Exposure
to
Arsenic
­
Primary
Application
Handler
13
Table
8The
Cancer
Risks
Associated
with
Exposure
to
Arsenic
­
Postapplication
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14
Table
9The
Cancer
Risks
Associated
with
Exposure
to
Chromium
­
Primary
Handler
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15
Table
10
The
Cancer
Risks
Associated
with
Exposure
to
Hexavalent
chromium
­
Postapplication
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16
Table
11
CCA
Occupational
Risk
Assessment
­
Summary
of
Primary
Handler
Exposure
Scenarios
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17
Table
12
CCA
Occupational
Risk
Assessment
­
Summary
of
Postapplication
Exposure
Scenarios
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18
1
BACKGROUND
The
purpose
of
risk
characterization
is
to
quantify
the
potential
health
risks
to
the
potential
receptors
associated
with
exposure
to
the
chemicals
of
concern.
Inorganic
Arsenical
wood
preservatives
containing
mixtures
of
arsenic,
chromium
and
copper
active
ingredients
are
most
commonly
formulated
as
Chromated
Copper
Arsenate
or
CCA.
The
mixture
prolongs
the
life
of
wood
by
preventing
mold,
fungi
and
insect
attack.
CCA
is
composed
of
a
mixture
of
Arsenic
(+
5),
Chromium
(+
6)
and
Copper
(+
2).
The
CCA
is
applied
by
forced
into
the
wood
under
high
pressure
and
is
trapped
in
the
intercellular
spaces
(
hence
the
name
pressure
treated
wood).
All
non
pressure
treatments
have
been
voluntarily
cancelled
by
the
registrants.
The
cancellation
letter
dated
May
28,
2003,
removed
all
non
pressure
treatments
on
EPA
Reg.
Nos.
3008­
21,
75341­
1
(
formerly
3008­
8),
and
75341­
7
(
formerly
3008­
68).
There
are
no
other
CCA
non
pressure
treatments.

Presented
herein
is
the
risk
characterization
of
the
"
occupational"
exposure
and
risk
assessment
for
industrial
workers
involved
in
both
pressure
and
non­
pressure
wood
treatments
using
Chromated­
Copper­
Arsenate.
These
risk­
estimates
are
calculated
using
the
exposure
parameters
and
exposure
point
concentrations
developed
in
the
Occupational
Exposure
and
Risk
Assessment
Section
and
the
toxicological
endpoints
reported
in
the
Hazard
Assessment
Sections.
The
scope
of
EPA­
registered
preservative
chemicals
covered
by
the
term
Chromated­
Copper­
Arsenate
includes:

°
Separate
chromium
(
Cr),
copper
(
Cu),
and
arsenic
(
As)
technical
source,
manufacturinguse
products
registered
with
the
Agency
for
use
in
formulating
inorganic
arsenical
preservative
mixtures
for
the
pressure­
treatment
of
wood;
and
°
Registered
industrial
end­
use
product
concentrates
containing
CCA
chemical
mixtures
of
Cr,
Cu,
and
As
intended
for
dilution
with
water
to
create
work
solutions
for
wood
pressure­
treatments.

The
current
risk
assessment
is
focusing
on
arsenic
and
chromium
only.
Cupric
Oxide,
the
form
of
copper
used
in
CCA
treatment
solutions,
is
not
included
as
an
active
ingredient
covered
under
this
RED.
Reregistration
requirements
for
Cupric
Oxide
will
be
addressed
separately
in
a
RED
document
for
Copper,
and
oxides,
Case
Number
4025,
slated
to
be
issued
at
a
future
date.

1.0
HAZARD
ASSESSMENT
1.1
Adequacy
of
the
Data
Base
The
toxicological
data
base
for
the
arsenic
and
chromium
compounds
found
in
inorganic
arsenicals
is
adequate
and
will
support
reregistration
eligibility
for
CCA
and
related
wood
preservative
pesticides.
The
hazard
assessment
of
inorganic
arsenic
and
chromium
are
summarized
in
following
sections.
2
1.2
Hazard
Assessment
of
Inorganic
Arsenic
The
acute
toxicity
summary
of
inorganic
arsenic
(
arsenic
acid
7.5%)
is
summarized
in
Table
1.
Humans
are
very
sensitive
to
arsenic
toxicity
when
compared
with
other
experimental
animals.
Inorganic
arsenic
is
acutely
toxic,
and
ingestion
of
large
doses
leads
to
gastrointestinal
symptoms,
disturbances
of
cardiovascular
and
nervous
system
functions,
and
eventually
death.
The
effects
seen
after
short­
term
arsenic
exposure
(
appearance
of
edema,
gastrointestinal
or
upper
respiratory
symptoms)
differ
from
those
after
longer
exposure
(
symptoms
of
skin
and
neuropathy).
Some
of
the
effects
after
short­
term
exposure
tended
to
subside
gradually
from
the
5th
day
of
the
illness,
despite
continuous
intakes
of
the
poison.
In
contrast,
symptoms
of
peripheral
neuropathy
appeared
in
some
individuals
even
after
the
cessation
of
arsenical
intakes
On
August
21,
2001,
the
OPP's
Hazard
Identification
Assessment
Review
Committee
(
HIARC)
evaluated
the
toxicology
data
base
of
Inorganic
Arsenic
and
established
the
toxicological
endpoints
for
occupational
exposure
risk
assessments.
On
October,
23­
25
2001,
the
FIFRA
Scientific
Advisory
Panel
(
SAP)
met
and
discussed
some
issues
concerning
the
end
points
proposed
by
the
HIARC.
The
conclusions
related
to
inorganic
arsenic
are
summarized
in
Table
2.
3
Table
1.
Acute
Toxicity
Summary
of
Arsenic
Acid
(
75%)

Guideline
Reference
No.
Study
Type
MRID/
Data
Accession
No.
Results
Toxicity
Category
81­
1
(
OPPTS
870.1100)
Acute
Oral
404090­
01
Mouse
LD50
=

141
mg/
kg
=

160
mg/
kg
M+
F
=
150
mg/
kg
II
26356
Rat
LD50
=

76
mg/
kg
=

37
mg/
kg
M+
F
=
52
mg/
kg
I
81­
2
(
OPPTS
870.1200)
Acute
Dermal
26356
Rabbit
LD50
=

1750
mg/
kg
=

2300
mg/
kg
II
81­
3
(
OPPTS
870.1300)
Acute
Inhalation
404639­
02
Mouse
LC50
=

1.153
mg/
L
=

0.79
mg/
L
M+
F
=
1.040
mg/
L
II
81­
4
(
OPPTS
870.2400)
Primary
Eye
Irritation
26356
Rabbit
3/
6
animals
died
by
day
7.
The
3
surviving
animals
were
sacrificed
on
day
9
because
of
severe
ocular
irritation
and
corrosion.
I
81­
5
(
OPPTS
870.2500)
Primary
Skin
Irritation
26356
Rabbit
At
30
minutes,
all
animals
showed
moderate
to
severe
erythema
and
slight
to
severe
edema.
All
animals
died
prior
to
the
24
hour
observation.
I
81­
6
(
OPPTS
870.2600)
Dermal
Sensitization
406462­
01
Guinea
Pig
Not
a
Sensitizer
4
Table
2.
Toxicological
Endpoints
for
Assessing
Occupational
Exposures/
Risks
to
Arsenic
(
V)

EXPOSURE
SCENARIO
DOSE
(
mg/
kg/
day)
ENDPOINT
STUDY
Acute
Dietary
This
risk
assessment
is
not
required.

Chronic
Dietary
This
risk
assessment
is
not
required.

Incidental
Short­
and
Intermediate­
Term
Oral
LOAEL=
0.05
MOE
=
30
Based
on
edema
of
the
face,
gastrointestinal,
upper
respiratory,
skin,
peripheral
and
neuropathy
symptoms
Franzblau
et
al.(
1989)
and
Mizuta
et
al.
(
1956)

Dermal
Short­
and
Intermediate­
Term
(
a)
(
b)
LOAEL=
0.05
MOE
=
30
Based
on
edema
of
the
face,
gastrointestinal,
upper
respiratory,
skin,
peripheral
and
neuropathy
symptoms
Franzblau
et
al.(
1989)
and
Mizuta
et
al.
(
1956)

Dermal
Long­
Term
(
a)
(
b)
NOAEL=
0.0008
MOE
=
3
Based
on
hyperpigmentation,
keratosis
and
possible
vascular
complications.
Tseng
et
al.
(
1968)
and
Tseng
(
1977)

Inhalation
Short­
and
Intermediate­
Term(
c)
LOAEL=
0.05
MOE
=
30
Based
on
edema
of
the
face,
gastrointestinal,
upper
respiratory,
skin,
peripheral
and
neuropathy
symptoms
Franzblau
et
al.(
1989)
and
Mizuta
et
al.
(
1956)

Inhalation,
Long­
Term
NOAEL=
0.0008
MOE
=
3
Based
on
hyperpigmentation,
keratosis
and
possible
vascular
complications.
Tseng
et
al.
(
1968)
and
Tseng
(
1977)

Carcinogenicity
­
Inhalation
(
Inhalation
Risk)
CSF
=
15.1
(
d)
(
mg/
kg/
day)­
1
(
For
general
Population)
Lung
cancer
Chronic
epidemiological
inhalation
study
on
humans
CSF
=
5.0
(
e)
(
mg/
kg/
day)­
1
(
For
8
hour
working
day)

Carcinogenicity
­
Oral
Ingestion
(
Oral
and
Dermal
Risks)
CSF=
3.67
(
f)
(
mg/
kg/
day)­
1
Internal
organ
cancer
(
liver,
kidney,
lung
and
bladder)
and
skin
cancer
Chronic
epidemiological
oral
study
on
humans
Note:
(
a).
MOE
=
Margin
of
Exposure;
NOAEL
=
No
observed
adverse
effect
level;
and
LOAEL
=
Lowest
observed
adverse
effect
level.
(
b).
The
dermal
absorption
factor
=
6.4%.
(
Note:
The
FIFRA
Scientific
Advisory
Panel
recommended
use
of
a
lower
value
of
2­
3%.
The
occupational
assessment
in
the
risk
assessment
uses
6.4
percent
dermal
absorption
because
the
handlers
and
workers
are
exposed
to
the
arsenic
residue
from
the
aqueous
solution
during
mixing,
loading,
and
handling
or
are
exposed
to
newly
treated,
or
"
wet'
wood
which
has
arsenic
residues
on
the
surface
of
the
wood).
(
c).
For
inhalation
exposure,
a
default
absorption
factor
of
100%
is
used.
Route­
to­
route
extrapolation
is
used
to
estimate
the
exposed
dose.
(
d).
Inhalation
unit
risk
(
IUR)
is
derived
from
a
24
hour
exposure
inhalation
unit
risk
with
a
value
of
4.3
x
10­
3
(
µ
g/
m3)­
1.
To
convert
the
IUR
to
a
cancer
slope
factor
in
units
of
(
mg/
kg/
day)
­
1
for
the
general
population
=
IUR
(
µ
g/
m3)­
1
x
1/
70
kg
x
20
m3/
day
x
1
mg/
1,000
µ
g
(
EPA,
1989).
(
e).
For
workers
working
8
hour
per
day,
the
inhalation
cancer
slope
factor
(
CSF)
derived
from
the
24
hour
IUR
for
general
population,
is
adjusted
for
an
8
hour
work
day.
CSF
for
8­
hr
work
day
=
general
population
CSF
of
15.1
(
mg/
kg/
day)­
1
x
(
8hrs/
24
hrs)
=
5.0
(
mg/
kg/
day)­
1.
(
e).
CSFis
derived
from
the
risk
assessment
associated
with
inorganic
in
drinking
water
are
presented
in
2000.
The
2001
National
Research
Council
(
NRC)
update
made
specific
recommendation
with
respect
to
the
overall
cancer
risk
estimates.
The
Agency
is
currently
considering
these
recommendations
and
their
potential
impact
on
the
cancer
potency
estimate.
Based
on
the
Agency's
considerations
of
these
recommendations,
the
current
proposed
cancer
potency
number
may
change
in
the
final
version
of
this
risk
assessment.
5
1.3
Hazard
Assessment
of
Chromium
(
VI)
The
acute
toxicity
of
Chromium
(
VI)
is
summarized
in
Table
3.
In
acute
toxicity
animal
studies,
administration
of
chromium
(
VI)
(
as
chromic
acid)
by
the
oral,
dermal,
and
inhalation
routes
resulted
in
significant
acute
toxicity
as
measured
by
lethality.
The
measured
oral
LD50
in
rats
was
reported
as
52
mg/
kg,
the
dermal
LD50
as
57
mg/
kg,
and
the
inhalation
LC50
as
0.217
mg/
L,
placing
chromium
(
VI)
in
Toxicity
Category
I
for
acute
lethality.
Human
reports
of
death
after
ingestion
of
chromium
show
lethality
at
similar
dose
levels
(
ATSDR,
1998).
Chromium
(
VI)
is
a
significant
eye
and
skin
irritant,
and
severe
allergic
reactions
consisting
of
redness
and
swelling
of
the
skin
have
also
been
noted
in
exposed
animals
and
humans.

Subchronic
oral
toxicity
studies
in
experimental
animals
have
demonstrated
hematologic
and
hepatic
effects
from
repeated
oral
exposure
to
Cr(
VI)
(
NTP,
1996).
Oral
ingestion
of
Cr(
VI)
compounds
in
experimental
animals
also
results
in
significant
developmental
toxicity
Trivedi
et
al
(
1989)
observed
reported
decreased
fetal
weight,
increased
resorption,
absence
of
uterine
implantation,
and
increased
abnormalities
(
tail
kinking,
delay
ossification
of
the
cranium)
in
mice
exposed
to
250,
500,
and
1,000
ppm
potassium
dichromate
daily
through
drinking
water
during
the
entire
gestational
period.
Other
investigators
have
also
reported
developmental
effects
(
Junaid
et
al.,
1996;
Kanojia,
et
al.,
1996).
Cr
(
VI)
is
known
to
be
carcinogenic
in
humans
by
the
inhalation
rout
of
exposure
((
U.
S.
EPA
2000),
and
some
data
suggest
that
orally
ingested
hexavalent
chromium
may
also
be
carcinogenic
by
this
route,
although
further
investigation
is
necessary
(
Costa,
1997).

On
August
28,
2001,
the
OPP's
Hazard
Identification
Assessment
Review
Committee
(
HIARC)
evaluated
the
toxicology
data
base
of
Cr(
VI)
and
established
the
toxicological
endpoints
for
occupational
exposure
risk
assessments.
On
October,
23­
25
2001,
the
antimicrobial
Division,
Office
of
Pesticide
Programs
presented
a
series
of
issues
to
the
FIFRA
Scientific
Advisory
Panel
(
SAP)
which
included
questions
on
the
validity
of
the
toxicological
endpoints
for
Cr(
VI).
The
endpoints
selected
for
Cr(
VI)
for
use
in
CCA
occupational
risk
assessment
as
a
result
of
the
HIARC
meeting
and
the
FIFRA
SAP
meeting
are
summarized
in
Table
X
­
4.
To
address
of
concern
for
potential
skin
irritation
and
allergic
potential
for
Cr(
VI)
from
occupational
exposure,
and
in
accordance
with
OPP
policy,
it
was
concluded
that
precautionary
label
statements
should
be
included
on
the
CCA
wood
preservative
treatment
solutions
used
in
pressure
treatment
facility.

1.4
FQPA
Consideration
No
FQPA
concerns
will
be
addressed
in
assessing
risks
associated
with
occupational
exposure
scenarios.

2.0
EXPOSURE
ASSESSMENT
The
purpose
of
the
exposure
assessment
is
to
estimate
the
nature
and
magnitude
of
potential
chemical
intakes
for
various
receptors.
Detailed
exposure
assessment
associated
with
occupational
exposure
to
CCA
is
addressed
in
the
Occupational
Exposure
and
Risk
Assessment
Section.
Table
3:
Acute
Toxicity
Summary
of
the
Chromium
(
VI)
6
Guideline
Study
Type
[
Substance]
MRID/
Literature
Results
Toxicity
Category
81­
1
(
OPPTS
870.1100)
Acute
Oral/
Rat
[
Chromic
Acid,
100%
a.
i.]
434294­
01
LD50
=

56
mg/
kg
=

48
mg/
kg
M+
F
=
52
mg/
kg
I
81­
2
(
OPPTS
870.1200)
Acute
Dermal/
Rabbit
[
Chromic
Acid,
100%
a.
i.]
434294­
02
LD50
=

>
48
mg/
kg
=

48
mg/
kg
M+
F
=
57
mg/
kg
I
81­
3
(
OPPTS
870.1300)
Acute
Inhalation/
Rat
[
Chromic
Acid,
100%
a.
i.]
434294­
03
LC50
=

0.263
mg/
L
=

0.167
mg/
L
M+
F
=
0.217
mg/
L
I
81­
4
(
OPPTS
870.2400)
Primary
Eye
Irritation
[
Various
Cr(
VI)
compounds]
Literature
Waiver
Corrosive
I
81­
5
(
OPPTS
870.2500)
Primary
Dermal
Irritation
[
Various
Cr(
VI)
compounds]
Literature
Waiver
Corrosive
I
81­
6
(
OPPTS
870.2600)
Dermal
Sensitization
/
Guinea
Pig
[
Various
Cr(
VI)
compounds]
Literature
Strong
sensitizer
7
Table
4.
Toxicological
Endpoints
for
Assessing
Occupational
Exposures/
Risks
to
Chromium
(
VI)

EXPOSURE
SCENARIO
DOSE
(
mg/
kg/
day)
ENDPOINT
STUDY
Acute
Dietary
This
risk
assessment
is
not
required.

Chronic
Dietary
This
risk
assessment
is
not
required.

Incidental
Shortand
Intermediate­
Term
Oral
(
a)
NOAEL=
0.5of
chromic
acid
[
0.12
of
Cr(
VI)]

MOE
=
100
based
on
the
increased
incidence
of
maternal
mortality
and
decreased
body
weight
gain
at
LOAEL
of
2.0
[
0.48
of
Cr
(
VI)]
Developmental/
Rabbit
Tyl,
1991
Dermal
Exposure
(
b)

(
All
Durations)
Because
dermal
irritation
and
dermal
sensitization
are
the
primary
concern
through
the
dermal
exposure
route,
no
toxicological
end­
point
is
selected
for
use
in
assessing
dermal
exposure
risks
to
chromium.

Inhalation
Exposure
(
All
Durations)
(
a)
LOAEL=
0.002
mg/
m3;
(
or
2.3
x
10­
4
mg/
kg/
day)
MOE
=
100
nose
and
throat
symptoms
observed
at
the
0.002
mg/
m3
level
Linberg
and
Hedenstierna,
1983.

Carcinogenicity
­
Inhalation
(
Inhalation
Risk)
CSF=
40.6
(
c)(
mg/
kg/
day)­
1
(
For
general
Population)
Lung
tumors
IRIS
CSF=
13.5
(
d)(
mg/
kg/
day)­
1
(
For
8
hour
working
day)

Note:
(
a).
MOE
=
Margin
of
Exposure;
NOAEL
=
No
observed
adverse
effect
level;
and
LOAEL
=
Lowest
observed
adverse
effect
level.
(
b).
The
dermal
absorption
factor
for
Cr(
VI)
=
1.3%
for
handler
dermal
contact
with
chromated
arsenical
pesticides.
(
c)
The
24
hours
inhalation
unit
risk
is
1.16
x
10­
2
(
µ
g/
m3)­
1
which
can
also
be
expressed
as
0.0116
m3/

g.
To
convert
the
air
concentration
to
a
dose
to
yield
units
of
kg­
day/
mg
or
(
mg/
kg/
day)­
1
the
unit
risk
is
expressed
mathematically
as
0.0116
m3/

g
x
day/
20
m3
x
1000

g/
mg
x
70
kg
=
40.6
(
mg/
kg/
day)­
1
(
EPA,
1989).
(
d)
For
workers
working
8
hour
per
day,
the
inhalation
cancer
slope
factor
(
CSF)
derived
from
the
24
hour
CSF
for
the
general
population,
is
adjusted
for
an
8
hour
work
day
.
CSF
for
8­
hr
work
day
=
general
population
CSF
of
40.6
(
mg/
kg/
day)­
1
x
(
8hrs/
24
hrs)
=
13.5
(
mg/
kg/
day)­
1.
8
2.1
Identification
of
Potential
Receptor
Populations
The
exposure
scenarios
developed
for
this
RED
Chapter
are
representative
of
potential
occupational
exposures
to
the
chemicals
of
concern
over
short­
term
(
1
day
to
1
month),
intermediate­
term
(
1­
6
months),
and
long­
term
(
>
6
months)
exposure
durations.
Potential
occupational
exposures
were
identified
for
both
the
handlers
and
postapplication
activities.

2.1.1
Primary
Occupational
Handlers
The
CCA
is
applied
by
forcing
into
the
wood
under
high
pressure
and
is
trapped
in
the
intercellular
spaces
(
hence
the
name
pressure
treated
wood).
In
this
risk
assessment,
the
potential
occupational
workers
involved
in
the
application
of
the
product
will
be
addressed.

For
wood
treatment
plant
workers
involved
with
pressure
treatments,
one
potential
exposure
scenario
is
identified.

°
Potential
Exposure
Scenario
1
­
Worker
applying
diluted
chromated
arsenical
liquid
treatment
solutions
at
a
pressure
treatment
plant
using
an
automated/
closed
delivery
system.
In
this
risk
assessment,
the
risk
associated
with
both
Treatment
Operator
(
TO)
and
Treatment
Assistant
(
TA)
will
be
assessed.
These
worker
activities
involve
applying
the
product
using
an
automated/
closed
delivery
system
to
mechanically
pump
a
1­
2%
CCA­
C
treatment
solution
from
the
"
work
tank"
to
the
pressure
treatment
cylinder
(
i.
e.,
retort)
to
pressure
treat
a
charge
of
wood.
Exposure
may
occur
to
treatment
operators
and
treatment
assistants
while
handling
leads
and
charge
chains,
opening
and
closing
retort
doors,
as
well
as
cleaning
and
maintenance
of
systems.
Treatment
operators
operate
and
monitored
application
system
valves
and
controls,
they
sometimes
opened
and
closed
cylinder
doors,
and
they
supervise
the
insertion
and
removal
of
charges
(
loads
of
dried,
debarked
poles
or
untreated
ties)
of
poles
from
the
treatment
cylinders
2.1.2
Postapplication
Occupational
Receptors
Postapplication
exposure
occurs
following
the
application
of
a
pesticide
product.
In
the
wood
pressure
treatment
plants,
postapplication
occurs
when
job
functions
require
that
there
be
contact
with
freshly
treated
wood
and
pressure
treatment
machinery
(
e.
g.,
retort
door)
or
pipes,
or
when
occupying
treatment
areas
directly
after
pesticide
applications.
A
study
by
the
Chemical
Manufacturer's
Association
(
CMA)
entitled
the
"
Assessment
of
Potential
Inhalation
and
Dermal
Exposure
Associated
with
Pressure
Treatment
of
Wood
with
Arsenical
Products"
(
MRID
455021­
01)
was
submitted
to
EPA
as
part
of
the
reregistration
requirements.
In
this
report,
six
different
potential
postapplication
occupational
receptors
are
identified.

°
Loader
Operator
­
Worker
scenario
pertains
to
a
formulating
facility
or
wood
pressure
treatment
facility.
Worker
operates
self­
propelled
vehicles
that
are
used
to
9
load
wood
products
onto
and
off
of
trams,
and
to
move
charges
into
and
out
of
treatment
cylinders
and
to
and
from
load
out
areas.
Worker
may
perform
certain
out­
of­
cab
tasks
such
as
collect
tank
samples,
perform
test
boring
and
lab
analysis
of
treatment
solutions
of
wood.

°
Test
Borer
­
Worker
scenario
pertains
to
a
wood
pressure
treatment
facility.
Worker
takes
pole
cores
to
test
for
CCA
penetration.
May
also
test
concentration
of
lots
of
CCA,
and
perform
other
QC
laboratory
duties.

°
Tram
Setter
­
Worker
positions
trams
for
loading,
places
wood
spacers
on
trams
where
needed
to
elevate
wood
to
be
treated.
Does
all
lead
and
chain
handling
for
that
site.
Removes
and
shreds
all
bands
from
treated
stacks
of
lumber.
Sweeps
and
pressure­
washes
pad
areas.
Picks
up
and
disposes
of
treated
wood
waste.
May
also
perform
various
labor
and
cleanup
duties
in
drip
pad
area.

°
Supervisor
­
Supervisor
duties
were
not
fully
described
in
the
study
report.

°
Tally
Man
­
Main
duties
include
counting
and
inspection
of
incoming
and
outgoing
truckloads
of
wood
products,
and
supervision
of
loading
and
unloading
of
lumber
trucks
at
drip
pad
and
elsewhere.
May
also
perform
some
treatment­
related
duties,
such
as
end­
marking
of
treated
items
or
chaining
of
charges
for
treatment.
His
office
was
located
immediately
adjacent
to
the
drip
pad.

°
Stacker
Operator
­
Worker
operates
a
lumber
stacking
device,
which
arranges
treated
boards
in
stacks
for
banding
and
shipment
to
customers,
and
removes
wood
spacer
sticks
from
bundles
of
treated
boards.
This
worker
manually
positions
ends
of
all
treated
boards
moving
through
devices
so
they
are
evenly
positioned.

2.2
Identification
of
Potential
Exposure
Assumptions
In
order
to
calculate
the
exposure
of
chemicals
as
a
result
of
exposure
to
the
chemicals
of
concern
(
CCA)
and
to
estimate
the
associated
potential
health
risks,
a
number
of
exposure
parameters
must
first
be
quantified.
In
this
risk
assessment,
the
exposure
estimates
for
both
the
primary
occupational
handlers
(
wood
treatment
plant
workers
involved
with
pressure
treatments),
and
the
postapplication
exposure
are
using
the
results
of
the
"
Assessment
of
Potential
Inhalation
and
Dermal
Exposure
Associated
with
Pressure
Treatment
of
Wood
with
Arsenical
Products"
(
MRID
455021­
01)
submitted
by
the
American
Chemistry
Council
(
ACC,
2001).

3.0
RISK
CHARACTERIZATION
The
risk
characterization
(
both
non­
carcinogenic
and
carcinogenic
risks)
associated
with
occupational
handler
and
postapplication
exposure
to
the
chemicals
of
concern
(
inorganic
arsenic
and
chromium)
in
CCA
are
presented.

3.1
Non­
carcinogenic
Risk
Characterization
10
Based
on
the
discussions
in
the
hazard
assessment
and
exposure
assessment,
the
total
daily
exposure
and
Margin
of
Exposure
(
MOE)
for
each
potential
exposure
receptor
and
potential
exposure
routes
are
calculated.
The
non­
carcinogenic
risk
characterizations
of
exposure
assessment
for
the
primary
exposure
scenarios
for
both
arsenic
and
hexavalent
chromium
are
summarized
in
Table
5.
The
non­
carcinogenic
risk
characterizations
of
exposure
assessment
for
the
postapplication
potential
exposure
receptors
for
both
arsenic
and
hexavalent
chromium
are
summarized
in
Table
6.
In
general,
if
the
MOE
is
greater
than
the
specified
target
MOE,
the
risk
is
considered
not
of
concern.
Otherwise,
when
the
MOE
is
less
than
the
specified
uncertainty
factor,
exposure
to
the
specific
chemical
through
the
potential
exposure
route
is
considered
to
indicate
a
potential
health
concern.
In
both
Tables
5
and
6,
the
exposure
scenarios
with
the
calculated
MOE
in
the
cells
marked
with
(

)
pose
a
risk
of
concern.
Since
no
inhalation
studies
are
available,
the
OPP's
Hazard
Identification
Assessment
Review
Committee
(
HIARC)
selected
the
same
studies
as
for
the
dermal
risk
assessments.
For
arsenic
risk
assessment,
the
HIARC
recommended
that
the
dose
from
both
dermal
and
inhalation
exposure
be
combined
and
then
be
compared
to
the
oral
LOAEL
of
0.05
mg/
kg/
day
for
short
and
intermediate
term
exposure
and
the
oral
NOAEL
of
0.0008
mg/
kg/
day
for
long­
term
exposure
to
evaluate
the
total
risk
concern.
However,
because
the
dermal
exposure
is
higher
than
the
inhalation
exposure,
there
is
minimum
increase
in
the
combined
risk.

3.2
Carcinogenic
Risk
Characterization
The
carcinogenic
concerns
for
occupational
exposure
to
both
inorganic
arsenic
and
hexavalent
chromium
are
presented.
In
general,
if
the
calculated
cancer
risk
is
greater
than
1x
10­
6,
the
associated
exposure
scenario
is
posing
a
cancer
risk
of
concern.
Otherwise,
if
the
calculated
cancer
is
less
than
1x
10­
6
,
the
associated
exposure
scenario
is
not
of
concern.

3.2.1
Arsenic
Carcinogenic
Risk
Characterization
The
dermal
and
inhalation
cancer
risks
associated
with
inorganic
arsenic
for
primary
exposure
scenarios
are
calculated
and
summarized
in
Table
7.
The
dermal
and
inhalation
cancer
risks
associated
with
inorganic
arsenic
for
postapplication
exposure
receptors
are
calculated
and
summarized
in
Table
8.
The
cells
marked
with
(

)
stand
for
the
exposure
scenario
pose
a
risk
concern.

3.2.2
Chromium
Carcinogenic
Risk
Characterization
There
is
no
carcinogenic
concern
for
dermal
exposure
to
hexavalent
chromium.
The
potential
cancer
risks
associated
with
inhalation
exposure
to
the
hexavalent
chromium
in
CCA
are
calculated
and
summarized
in
Table
9
and
10
The
exposure
scenarios
for
handler
and
postapplication
activities
are
all
of
concern
(
i.
e.,
handler
risks
are
1.8
x
10­
4
and
1.6
x
10­
4
;
postapplication
risks
ranged
from
1.6
x
10­
4
to
2.0
x
10­
4).
However,
it
is
important
to
note
that
all
inhalation
monitoring
samples
were
below
the
limit
of
detection
(
i.
e.,
cancer
risks
are
based
on
½
LOD).
The
analytical
technique
used
to
determine
the
amount
of
Cr+
6
in
the
sample
was
inadequate.
11
Table
5.
Risk
Characterization
of
Exposure
Assessment
to
Primary
Handler
Short­,
Intermediate­,
and
Long­
term
 
Non­
Cancer
Risks
to
CCA
Exposure
Scenario
(
Scen.
#)
Chemical
of
Concern
Dermal
Inhalation
Dermal
+
Inhalation
Short­

and
Intermediateterm
MOEa
Long­
term
MOEb
Short­,

and
Intermediateterm
MOEc
Long­
term
MOEd
Short­,

and
Intermediateterm
MOEc
Long­
term
MOEd
(
1)
Applying
Liquid
Formulations
at
Pressure
Treatment
Plants
using
an
Automatic/
Closed
Delivery
System
(
Operating
and
Closing
the
Retort)
­

Treatment
Operator
(
TO)
Arsenic
(
As)
16
(

)

(
Target
MOE
30)
0.3
(

)

(
Target
MOE
3)
467
(
Target
MOE
30)
7
(
Target
MOE
3)
16
(

)

(
Target
MOE
30)
0.3
(

)

(
Target
MOE
3)

Hexavalent
chromium
(
Cr)
NA
NA
7
(

)

(
Target
MOE
100)
7
(

)

(
Target
MOE
100)
­
­

(
1)
Applying
Liquid
Formulations
at
Pressure
Treatment
Plants
using
an
Automatic/
Closed
Delivery
System
(
Operating
and
Closing
the
Retort)
­

Treatment
Assistant
(
TA)
Arsenic
(
As)
48
(
Target
MOE
30)
0.8
(
Target
MOE
3)
769
(
Target
MOE
30)
12
(
Target
MOE
3)
45
(
Target
MOE
30)
0.7
(
Target
MOE
3)

Hexavalent
chromium
(
Cr)
NA
NA
7
(

)

(
Target
MOE100)
7
(

)

(
Target
MOE
100)
­
­

Footnotes:

a
Short­
and
Intermediate­
term
dermal
MOE
=
dermal
NOAEL
/
Short­
and
Intermediate­
term
dermal
daily
dose
(
mg/
kg/
day).
Where
As
LOAEL
=
0.05
mg/
kg/
day.

b
Long­
term
MOE
=
dermal
NOAEL/
Long­
term
dermal
daily
dose
(
mg/
kg/
day).
Where
As
NOAEL
=
0.0008
mg/
kg/
day.

c
Short­,
Intermediate­
term
inhalation
MOE
=
inhalation
NOAEL
/
Short­,
Intermediate­
term
inhalation
dose
(
mg/
kg/
day).
Where
As
LOAEL
=
0.05
mg/
kg/
day,
and
Cr
NOAEL
=
6.9
x
10­
5
mg/
kg/
day
(
derived
from
a
LOAEL
=
2.4
x10­
4
mg/
m3).

d
Long­
term
inhalation
MOE
=
inhalation
NOAEL
or
LOAEL
/
long­
term
inhalation
dose.
Where
As
NOAEL
=
0.0008
mg/
kg/
day
and
Cr
NOAEL
=
6.9
x
10­
5
mg/
kg/
day
(
derived
from
a
LOAEL
=
2.4
x10­
4
mg/
m3).

e
MOE
=
inhalation
NOAEL
or
LOAEL
/
long­
term
inhalation
dose.
Where
As
NOAEL
=
0.0008
mg/
kg/
day
and
Cr
NOAEL
=
6.9
x
10­
5
mg/
kg/
day
(
derived
from
a
LOAEL
=
2.4
x10­
4
mg/
m3).

NA
Not
applicable
NOTE:
Recommended
Dermal
MOE
for
Arsenic:
short­
and
intermediate­
term
=
30;
long­
term
=
3.

Recommended
Inhalation
MOE
for
Arsenic:
short­
and
intermediate­
term
=
30,
long­
term
=
3.

Recommended
Inhalation
MOE
for
Chromium
VI:
Short­,
intermediate­
and
long­
term
=
100
The
exposure
scenario
with
the
calculated
MOE
in
the
cell
marked
with
(

)
pose
a
risk
concern.
12
Table
6.
Risk
Characterization
of
Exposure
Assessment
to
Postapplication
­
Short­,
Intermediate­,
and
Long­
term
 
Non­
Cancer
Risks
to
CCA
Exposure
Scenario
(
Scen.
#)
Chemical
of
Concern
Dermal
Inhalation
Dermal
+
Inhalation
Short­

and
Intermediateterm
MOEa
Long­
term
MOEb
Short­,

and
Intermediateterm
MOEc
Long­
term
MOEd
Short­,

and
Intermediateterm
MOEc
Long­
term
MOEd
(
1)
Loader
Operator
Arsenic
(
As)
21
(

)
0.3
(

)
581
9
20
(

)
0.3
(

)

Chromium
(
Cr)
NA
NA
6
(

)
6
(

)
­
­

(
2)
Test
Borer
Arsenic
(
As)
263
4
1471
24
223
4
Chromium
(
Cr)
NA
NA
NA
NA
­
­

(
3)
Tram
Setter
Arsenic
(
As)
8
(

)
0.1
(

)
195
3
8
(

)
0.1
(

)

Chromium
(
Cr)
NA
NA
6
(

)
6
(

)
­
­

(
4)
Supervisor
Arsenic
(
As)
16
(

)
0.3
(

)
325
5
15
(

)
0.3
(

)

Chromium
(
Cr)
NA
NA
6
6
(

)
­
­

(
5)
Tally
Man
Arsenic
(
As)
18
(

)
0.3
(

)
1136
18
18
(

)
0.3
Chromium
(
Cr)
NA
NA
NA
NA
NA
NA
(
6)
Stacker
Operator
Arsenic
(
As)
38
0.6
(

)
1515
24
38
0.6
(

)

Chromium
(
Cr)
NA
NA
6
(

)
6
(

)
­
­

Footnotes:

a
Short­
and
Intermediate­
term
dermal
MOE
=
dermal
NOAEL
/
Short­
and
Intermediate­
term
dermal
daily
dose
(
mg/
kg/
day).
Where
As
LOAEL
=
0.05
mg/
kg/
day.

b
Long­
term
MOE
=
dermal
NOAEL/
Long­
term
dermal
daily
dose
(
mg/
kg/
day).
Where
As
NOAEL
=
0.0008
mg/
kg/
day.

c
Short­,
Intermediate­
term
inhalation
MOE
=
inhalation
NOAEL
/
Short­,
Intermediate­
term
inhalation
dose
(
mg/
kg/
day).
Where
As
LOAEL
=
0.05
mg/
kg/
day,
and
Cr
NOAEL
=
6.9
x
10­
5
mg/
kg/
day
(
derived
from
a
LOAEL
=
2.4
x10­
4
mg/
m3).

d
Long­
term
inhalation
MOE
=
inhalation
NOAEL
or
LOAEL
/
long­
term
inhalation
dose.
Where
As
NOAEL
=
0.0008
mg/
kg/
day
and
Cr
NOAEL
=
6.9
x
10­
5
mg/
kg/
day
(
derived
from
a
LOAEL
=
2.4
x10­
4
mg/
m3).

NA
Not
applicable
NOTE:
Recommended
Dermal
MOE
for
Arsenic:
short­
and
intermediate­
term
=
30;
long­
term
=
3.

Recommended
Inhalation
MOE
for
Arsenic:
short­
and
intermediate­
term
=
30,
long­
term
=
3.

Recommended
Inhalation
MOE
for
Chromium
VI:
Short­,
intermediate­
and
long­
term
=
100.

The
exposure
scenario
with
the
calculated
MOE
in
the
cell
marked
with
(

)
pose
a
risk
concern.
13
Table
7
The
Cancer
Risks
Associated
with
Exposure
to
Arsenic
­
Primary
Application
Handler
Exposure
Scenario
(
Scen.
#)
Route
of
Exposure
Cancer
Slope
Factor
(
CSF)
(
per
mg/
kg/
day)
Lifetime
Average
Daily
Dose
(
mg/
kg/
day)
Cancer
Risks
(
a)

(
1)
Treatment
Operator
(
TO)
Dermal
3.67
(
b)
1.12E­
3
4.1E­
3
(

)

Inhalation
5.0
(
c)
3.9E­
5
1.9E­
4
(

)

(
1)
Treatment
Assistant
(
TA)
Dermal
3.67
(
b)
3.8E­
4
1.4E­
3
(

)

Inhalation
5.0
(
c)
2.4E­
5
1.2E­
4
(

)

Note:
(
a).
Cancer
Risk
=
Slope
Factor
x
Lifetime
Average
daily
Dose
(
LADD).
The
exposure
scenario
with
the
calculated
cancer
risk
in
the
cell
marked
with
(

)
pose
a
risk
concern.
(
b).
CSF
is
derived
from
the
risk
assessment
associated
with
inorganic
in
drinking
water
are
presented
in
2000.
The
2001
National
Research
Council
(
NRC)
update
made
specific
recommendation
with
respect
to
the
overall
cancer
risk
estimates.
The
Agency
is
currently
considering
these
recommendations
and
their
potential
impact
on
the
cancer
potency
estimate.
Based
on
the
Agency's
considerations
of
these
recommendations,
the
current
proposed
cancer
potency
number
may
change
in
the
final
version
of
this
risk
assessment.
(
c).
For
workers
working
8
hour
per
day,
the
inhalation
potency
factor
is
derived
from
the
24
hour
inhalation
potency
factor
for
general
population.
CSF
=
15.1
(
mg/
kg/
day)­
1
x
(
8hrs/
24
hrs)
=
5.0
(
mg/
kg/
day)­
1.
14
Table
8
The
Cancer
Risks
Associated
with
Exposure
to
Arsenic
­
Postapplication
Exposure
Scenario
(
Scen.
#)
Route
of
Exposure
Cancer
Slope
Factor
(
Q*)
(
per
mg/
kg/
day)
Lifetime
Average
Daily
Dose
(
mg/
kg/
day)
Cancer
Risks
(
a)

(
1)
Loader
Operator
(
LO)
Dermal
3.67
(
b)
8.9E­
4
3.3E­
3
(

)

Inhalation
5.0
(
c)
3.1E­
5
1.5E­
4
(

)

(
2)
Test
Border
(
TB)
Dermal
3.67
(
b)
6.8E­
5
2.5E­
4
(

)

Inhalation
5.0
(
c)
1.2E­
5
6.0E­
5
(
3)
Tram
Setter
(
TS)
Dermal
3.67
(
b)
2.3E­
3
8.4E­
3
(

)

Inhalation
5.0
(
c)
9.4E­
5
4.7E­
4
(

)

(
4)
Supervisor
(
S)
Dermal
3.67
(
b)
1.1E­
3
4.1E­
3
(

)

Inhalation
5.0
(
c)
5.6E­
5
2.8E­
4
(

)

(
5)
Tally
Man
(
TM)
Dermal
3.67
(
b)
1.0E­
3
3.8E­
3
(

)

Inhalation
5.0
(
c)
1.6E­
5
8.0E­
5
(
6)
Stacker
Operator
(
SO)
Dermal
3.67
(
b)
4.8E­
4
1.8E­
3
(

)

Inhalation
5.0
(
c)
1.2E­
5
6.0E­
5
Note:
(
a).
Cancer
Risk
=
Slope
Factor
x
Lifetime
Average
daily
Dose
(
LADD).
The
exposure
scenario
with
the
calculated
cancer
risk
in
the
cell
marked
with
(

)
pose
a
risk
concern.
(
b).
CSF
is
derived
from
the
risk
assessment
associated
with
inorganic
in
drinking
water
are
presented
in
2000.
The
2001
National
Research
Council
(
NRC)
update
made
specific
recommendation
with
respect
to
the
overall
cancer
risk
estimates.
The
Agency
is
currently
considering
these
recommendations
and
their
potential
impact
on
the
cancer
potency
estimate.
Based
on
the
Agency's
considerations
of
these
recommendations,
the
current
proposed
cancer
potency
number
may
change
in
the
final
version
of
this
risk
assessment.
(
c).
For
workers
working
8
hour
per
day,
the
inhalation
potency
factor
is
derived
from
the
24
hour
inhalation
potency
factor
for
general
population.
CSF
=
15.1
(
mg/
kg/
day)­
1
x
(
8hrs/
24
hrs)
=
5.0
(
mg/
kg/
day)­
1.
15
Table
9
The
Cancer
Risks
Associated
with
Exposure
to
Chromium
­
Primary
Handler
Exposure
Scenario
(
Scen.
#)
Route
of
Exposure
Cancer
Slope
Factor
(
Q*)
(
per
mg/
kg/
day)
Lifetime
Average
Daily
Dose
(
mg/
kg/
day)
Cancer
Risks
(
a)

(
1)
Treatment
Operator
(
TO)
Dermal
NA
NA
NA
Inhalation
13.5(
b)
1.3E­
5
1.8E­
4
(

)

(
1)
Treatment
Assistant
(
TA)
Dermal
NA
NA
NA
Inhalation
13.5(
b)
1.2E­
5
1.6E­
4
(

)

Note:
(
a).
Cancer
Risk
=
Slope
Factor
x
Lifetime
Average
daily
Dose
(
LADD).
The
exposure
scenario
with
the
calculated
cancer
risk
in
the
cell
marked
with
(

)
pose
a
risk
concern.
(
b).
For
workers
working
8
hour
per
day,
the
inhalation
potency
factor
is
derived
from
the
24
hour
inhalation
potency
factor
for
general
population.
CSF
=
40.6
(
mg/
kg/
day)­
1
x
(
8hrs/
24
hrs)
=
13.5
(
mg/
kg/
day)­
1.
16
Table
10
The
Cancer
Risks
Associated
with
Exposure
to
Hexavalent
chromium
­
Postapplication
Exposure
Scenario
(
Scen.
#)
Route
of
Exposure
Cancer
Slope
Factor
(
Q*)
(
per
mg/
kg/
day)
Lifetime
Average
Daily
Dose
(
mg/
kg/
day)
Cancer
Risks
(
a)

(
1)
Loader
Operator
(
LO)
Dermal
NA
NA
­

Inhalation
13.5
(
b)
1.5E­
5
2.0E­
4
(

)

(
2)
Test
Border
(
TB)
Dermal
NA
NA
­

Inhalation
13.5
(
b)
NA
NA
(
3)
Tram
Setter
(
TS)
Dermal
NA
NA
­

Inhalation
13.5
(
b)
1.5E­
5
2.0E­
4
(

)

(
4)
Supervisor
(
S)
Dermal
NA
NA
­

Inhalation
13.5
(
b)
1.5E­
5
2.0E­
4
(

)

(
5)
Tally
Man
(
TM)
Dermal
NA
NA
­

Inhalation
13.5
(
b)
NA
NA
(
6)
Stacker
Operator
(
SO)
Dermal
NA
NA
­

Inhalation
13.5
(
b)
1.2E­
5
1.6E­
4
(

)

Note:
(
a).
Cancer
Risk
=
Slope
Factor
x
Lifetime
Average
daily
Dose
(
LADD).
The
exposure
scenario
with
the
calculated
cancer
risk
in
the
cell
marked
with
(

)
pose
a
risk
concern.
(
b).
For
workers
working
8
hour
per
day,
the
inhalation
potency
factor
is
derived
from
the
24
hour
inhalation
potency
factor
for
general
population.
CSF
=
40.6
(
mg/
kg/
day)­
1
x
(
8hrs/
24
hrs)
=
13.5
(
mg/
kg/
day)­
1.
17
Table
11
CCA
Occupational
Risk
Assessment
­
Summary
of
Primary
Handler
Exposure
Scenarios
Cells
Marked
with
(

)
Stand
for
the
exposure
Scenario
Pose
a
Risk
Concern
Potential
Receptor
(
Receptor
#)
Chemical
of
Concern
Non­
Carcinogenic
Cancer
Dermal
Inhalation
Dermal
+
Inhalation
Dermal
Inhalation
Short­,
and
Intermediateterm
Long­
term
Short­,
and
Intermediateterm
Long­
term
Short­,
and
Intermediateterm
Long­
term
(
1)
Applying
Liquid
Formulations
at
Pressure
Treatment
Plants
using
an
Automatic/
Closed
Delivery
System
(
Opening
and
Closing
the
Retort)
­
Treatment
Operator
(
TO)
Arsenic
(
As)
16
(

)

(
Target
MOE
30)
0.3
(

)

(
Target
MOE
3)
467
(
Target
MOE
30)
7
(
Target
MOE
3)
16
(

)

(
Target
MOE
30)
0.3
(

)

(
Target
MOE
3)
4.1E­
3
(

)
1.9E­
4
(

)

Chromium
(
Cr)
NA
NA
7
(

)

(
Target
MOE
100)
7
(

)

(
Target
MOE
100)
­
­
NA
1.8E­
4
(

)

(
1)
Applying
Liquid
Formulations
at
Pressure
Treatment
Plants
using
an
Automatic/
Closed
Delivery
System
(
Opening
and
Closing
the
Retort)
­
Treatment
assistant
(
TA)
Arsenic
(
As)
48
(
Target
MOE
30)
0.8
(
Target
MOE
3)
769
(
Target
MOE
30)
12
(
Target
MOE
3)
45
(
Target
MOE
30)
0.7
(
Target
MOE
3)
1.4E­
3
(

)
1.2E­
4
(

)

Chromium
(
Cr)
NA
NA
7
(

)

(
Target
MOE
100)
7
(

)

(
Target
MOE
100)
­
­
NA
1.6E­
4
(

)

Note:
a).
IA
=
HIARC
concluded
that
the
skin
irritation
and
the
skin
allergenicity
effects
are
the
primary
concern
for
Cr(
VI)
through
the
dermal
exposure
route.
For
the,
risk
concern
of
the
dermal
contact
of
Cr(
VI)
associated
with
worker
scenarios
should
be
addressed
through
precautionary
labeling
statements.

b).
NA
=
Not
Applicable.
18
Table
12
CCA
Occupational
Risk
Assessment
­
Summary
of
Postapplication
Exposure
Scenarios
Cells
Marked
with
(

)
Stand
for
the
exposure
Scenario
Pose
a
Risk
Concern
Potential
Receptor
(
Receptor
#)
Chemical
of
Concern
Non­
Carcinogenic
Cancer
Dermal
Inhalation
Inhalation
Dermal
Inhalation
Short­,
and
Intermediate­
term
Long­
term
Short­,
and
Intermediateterm
Long­
term
Short­,
and
Intermediateterm
Long­
term
(
1)
Loader
Operator
Arsenic
(
As)
21
(

)
0.3
(

)
581
9
20
(

)
0.3
(

)
3.3E­
3
(

)
1.5E­
4
(

)

Chromium
(
Cr)
NA
NA
6
(

)
6
(

)
­
­
­
(
c)
2.0E­
4
(

)

(
2)
Test
Borer
Arsenic
(
As)
263
4
1471
24
223
4
2.5E­
4
(

)
6.0E­
5
Chromium
(
Cr)
NA
NA
NA
NA
­
­
­
NA
(
3)
Tram
Setter
Arsenic
(
As)
8
(

)
0.1
(

)
195
3
8
(

)
0.1
(

)
8.4E­
3
(

)
4.7E­
4
(

)

Chromium
(
Cr)
NA
NA
6
(

)
6
(

)
­
­
­
2.0E­
4
(

)

(
4)
Supervisor
Arsenic
(
As)
16
(

)
0.3
(

)
325
5
15
(

)
0.3
(

)
4.1E­
3
(

)
2.8E­
4
(

)

Chromium
(
Cr)
NA
NA
6
6
­
­
­
2.0E­
4
(

)

(
5)
Tally
Man
Arsenic
(
As)
18
0.3
(

)
1136
18
18
(

)
0.3
(

)
3.8E­
4
(

)
8.0E­
5
Chromium
(
Cr)
NA
NA
NA
NA
NA
NA
­
NA
(
6)
Stacker
Operator
Arsenic
(
As)
38
0.6
(

)
1515
24
38
0.6
(

)
1.8E­
3
(

)
6.0E­
5
Chromium
(
Cr)
NA
NA
6
(

)
6
(

)
­
­
­
1.6E­
4
(

)

Note:
a).
Recommended
Dermal
and
Inhalation
MOE
for
Arsenic:
short­
and
intermediate­
term
=
30;
long
term
=
3;

Recommended
Inhalation
MOE
for
Chromium
VI:
Short­,
intermediate­
and
long­
term
=
100.

b).
NA
=
Not
Applicable.

c).
HIARC
concluded
that
the
skin
irritation
and
the
skin
allergenicity
effects
are
the
primary
concern
for
Cr(
VI)
through
the
dermal
exposure
route.
For
the,
risk
concern
of
the
dermal
contact
of
Cr(
VI)
associated
with
worker
scenarios
should
be
addressed
through
precautionary
labeling
statements.
19
6.0
UNCERTAINTY
ANALYSIS
6.1
Uncertainties
and
Deficiencies
in
Hazard
Assessment
There
are
uncertainties
inherent
in
each
hazard
assessment
procedure.
However,
there
are
some
uncertainties
specific
to
this
risk
assessment.
Since
no
inhalation
toxicity
on
studies
are
available
for
non­
cancer
endpoints,
oral
toxicity
endpoints
have
been
selected
for
this
risk
assessment
and
will
be
discussed
in
this
Section.

6.1.1
Using
Human
Data
Setting
the
Short­
term
and
Intermediate­
term
Incidental
Oral
and
Dermal
Exposures
End­
Points
The
lowest­
observed­
adverse­
effect
level
(
LOAEL)
selected
for
short­
and
intermediate­
term
dermal
exposures
for
arsenic
was
0.05
mg/
kg/
day
was
based
on
toxic
effects
including
edema
of
the
face;
gastrointestinal,
upper
respiratory,
skin,
peripheral
and
neuropathy
symptoms.
The
LOAEL
comes
from
the
work
of
Franzblau
et
al.
(
1989)
and
Mizuta
et
al.
(
1956)
who
examined
oral
exposure
to
individuals
exposed
during
a
reported
poisoning
incident
involving
the
presence
of
arsenic
[
probably
calcium
arsenate]
contained
in
soy­
sauce.
Both
HIARC
(
2001)
and
SAP
(
2001)
considered
this
is
an
appropriate
toxicological
endpoint
and
a
margin
of
exposure
of
30
from
this
LOAEL
is
recommended
for
non­
cancer
health
effects,
this
approach
may
either
over
or
underestimate
the
risk.
Although
some
panel
members
in
the
SAP
(
2001)
suggested
a
target
MOE
of
10
should
be
enough
for
this
risk
assessment.,
a
value
of
30
has
been
selected.

6.1.2
Dermal
Absorption
In
evaluating
the
exposure
of
inorganic
arsenic
through
the
dermal
exposure
route,
6.4%
dermal
absorption
is
used
in
the
dermal
risk
assessment.
The
value
of
6.4%
dermal
absorption
was
suggested
by
HIARC
(
2001)
and
was
selected
based
on
the
use
of
non­
human
primates
exposure
to
inorganic
arsenic
in
aqueous
solution
for
derivation
of
this
value
and
the
fact
that
this
was
a
well­
conducted
study.
It
is
observed
in
the
study
that
a
higher
dose
on
the
skin
resulted
in
lower
dermal
absorption
as
noted
above,
but
the
data
suggests
sufficient
variability
in
the
absorption
such
that
use
of
the
6.4%
dermal
absorption
value
is
sufficiently
but
not
overly
conservative.
The
SAP
(
2001)
was
suggesting
using
dermal
absorption
value
of
2­
3%
for
dermal
absorption
of
inorganic
arsenic
in
the
soil
or
wood
surface
residue.
However,
because
only
worker
exposure
scenarios
are
involved
in
this
risk
assessment,
the
dermal
absorption
value
of
6.4%
for
arsenic
in
water
was
used
in
this
risk
assessment.
Using
of
the
dermal
absorption
value
of
6.4%
may
overor
underestimate
the
risk.
20
6.1.3
Arsenic
Cancer
Potency
Factors
The
oral
cancer
potency
factor
of
3.67
per
mg/
kg/
day
is
derived
from
the
risk
assessment
associated
with
inorganic
arsenic
in
drinking
water.
Following
the
EPA's
presentation
of
the
risk
assessment
in
2000,
EPA
asked
the
National
Research
Council
(
NRC)
to
meet
again
to:
(
1)
review
EPA's
characterization
of
potential
human
health
risks
from
ingestion
of
inorganic
arsenic
in
drinking
water;
(
2)
review
the
available
data
on
the
carcinogenic
and
non­
carcinogenic
effects
of
inorganic
arsenic;
(
3)
review
the
data
on
the
metabolism,
kinetics
and
mechanism(
s)/
mode(
s)
of
action
of
inorganic
arsenic;
and
(
4)
identify
research
needs
to
fill
data
gaps.
In
2001
NRC
published
an
update
to
the
1999
NRC
report
and
concluded
that
(
1).
Arsenic­
induced
bladder
and
lung
cancers
still
should
be
the
focus
of
arsenic­
related
cancer
risk
assessment;
(
2)
the
southwestern
Taiwan
data
are
still
the
most
appropriate
for
arsenic­
related
cancer
risk
assessment;
and
(
3)
present
modes
of
action
data
are
not
sufficient
to
depart
from
the
default
assumption
of
linearity.
However,
the
2001
NRC
update
made
specific
recommendations
with
respect
to
the
overall
cancer
risk
estimate.
The
Agency
is
currently
considering
these
recommendations
and
their
potential
impact
on
the
cancer
potency
estimate.
Based
on
the
Agency's
considerations
of
these
recommendations,
the
current
proposed
cancer
potency
number
may
change
in
the
final
version
of
this
risk
assessment.

6.2
Uncertainties
and
Deficiencies
in
Exposure
Assessment
6.2.1
Data
Gaps
and
Limitations
In
the
course
of
the
occupational
exposure
chapter
development
for
this
RED,
chemical­
specific
handler
data
submitted
by
industry
and
identified
from
pertinent
literature
sources
were
reviewed
for
use
in
developing
exposure
estimates
for
worker
populations.
Certain
studies
are
presented
in
this
section
as
an
overview
of
the
available
data,
however
only
data
from
the
ACC
Worker
Exposure
Study
(
MRID
455021­
01)
(
ACC,
2001)
were
used
in
developing
appropriate
occupational
scenarios
for
wood
treatment
plant
workers
involved
with
pressure
treatments.
These
data
were
deemed
the
most
appropriate.

Hexavalent
chromium
inhalation
exposure
data
were
not
available
for
postapplication
exposure
for
scenarios
for
Tram
setter
(
TS)
and
Tally
Man
(
TM).

7.0
CONCLUSIONS
In
conclusion,
all
the
scenarios
for
non­
carcinogenic
and/
or
carcinogenic
risks
are
summarized
in
Tables
11
and
12
7.1
Primary
Handler
The
results
of
the
handler
exposure
and
risk
assessment
indicate
that
short­,
intermediate­,
and
long­
term
risks
for
dermal
and
inhalation
exposures
exceed
the
level
of
concern
for
arsenic
for
some
of
the
handler
scenarios.
For
arsenic,
a
margin
of
exposure
(
MOE)
of
30
or
more
for
shortand
intermediate­
term
dermal
risk
is
considered
not
to
be
of
concern
and
an
MOE
of
3
or
more
is
considered
not
to
be
of
concern
for
long­
term
risks.
The
calculated
MOE
for
both
treatment
operator
(
TO)
and
treatment
assistant
(
TA)
for
dermal
and
combined
(
dermal
+
inhalation)
21
exposure
of
arsenic
are
all
below
the
target
MOE
for
both
short­,
intermediate
and
long
term
scenarios.
Therefore,
the
results
of
the
risk
assessment
indicate
that
the
exposure
of
arsenic
through
dermal
route
posed
risks
of
concern
to
primary
handlers.

The
MOEs
for
the
inhalation
exposure
scenarios
presented
in
the
risk
assessment
do
not
exceed
the
Agency's
level
of
concern
for
both
short­,
and
intermediate­
term
and
long­
term
inhalation
exposures
to
arsenic
(
i.
e.,
MOEs
<
30)
.
Therefore,
for
inhalation
only,
exposure
through
arsenic
only
does
not
pose
risk
of
concern
to
primary
handler
scenarios.
However,
the
combined
risk
(
inhalation
+
dermal)
still
pose
risk
concern
for
both
TA
and
TO.

The
MOEs
for
the
inhalation
exposure
scenarios
presented
in
the
risk
assessment
exceed
the
Agency's
level
of
concern
long­
term
inhalation
exposures
to
hexavalent
chromium
(
i.
e.
MOEs
<
100)
for
both
TO
and
TA,
Exposure
to
hexavalent
chromium
pose
short­
term­,
intermediateterm
and
long
term
exposure
health
concern.
However,
to
chrome
pose
unacceptable
risk
to
both
TA
and
TO.

In
addition,
dermal
and
inhalation
exposure
to
arsenic
pose
a
cancer
risk
concern
for
all
primary
handler
scenarios
(
risk
exceed
the
level
of
concern
=
1E­
04).
Inhalation
exposure
to
chrome
also
pose
a
cancer
risk
concern
to
both
TA
and
TO.
It
is
important
to
know
that
all
inhalation
monitoring
samples
were
below
the
limit
of
detection(
i.
e.,
cancer
risks
are
based
on
½
LOD).
The
analytical
technique
used
to
determine
the
amount
of
Cr+
6
in
the
sample
was
inadequate.

7.2
Postapplication
Many
of
the
MOEs
for
the
dermal
exposure
scenarios
presented
in
the
risk
assessment
exceed
the
Agency's
level
of
concern
for
short­,
intermediate­
and
long­
term
dermal
exposures
to
arsenic.

The
risks
for
the
inhalation
exposure
scenarios
presented
in
the
risk
assessment
do
exceed
the
Agency's
level
of
concern
for
short­,
and
intermediate­
inhalation
exposures
to
arsenic
(
i.
e.,
MOEs<
100)
based
on
the
toxicological
information
for
arsenic.

The
risks
for
the
inhalation
exposure
scenarios
presented
in
the
risk
assessment
exceed
the
Agency's
level
of
concern
for
short­,
intermediate­
and
long­
term
inhalation
exposures
to
chromium
(
i.
e.
MOEs
<
30)
for
some
of
the
postapplication
scenarios
based
on
the
toxicological
information
for
Chromium
(
VI).

The
cancer
risks
assessment
associated
with
dermal
exposure
to
arsenic
pose
risk
concern
for
all
postapplication
worker
scenarios.
Inhalation
exposure
would
pose
cancer
risk
concern
for
Loader
Operator
,
Tram
Setter,
Supervisor
and
Staker
Operator,
but
not
to
Test
Borer
and
Tally
man.
All
inhalation
monitoring
samples
were
below
the
limit
of
detection,
but
because
the
analytical
technique
used
to
determine
the
amount
of
Cr+
6
in
the
sample
was
inadequate.
In
the
cancer
risk
calculation,
by
using
½
LOD,
inhalation
exposure
pose
cancer
risk
concerns
for
all
postapplication
scenarios.
22
8.0
REFERENCES
American
Chemistry
Council
(
ACC),
2001.
Arsenical
Wood
Preservatives
Task
Force.
Assessment
of
Potential
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Dermal
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24,
2001.

National
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1999.
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National
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Surrogate
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1998.
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from
the
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August
1998.

U.
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1984.
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of
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D.
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1984.

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U.
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EPA,
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C.
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S.
EPA,
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875­
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Residential
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Office
of
Pesticide
Programs,
Health
Effects
Division.
February
1998.

U.
S.
EPA,
2002.
Inorganic
Arsenic
­
Report
of
the
Hazard
Identification
Assessment
Review
Committee;
Inorganic
Chromium
­
Report
of
the
Hazard
Identification
Assessment
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J.
Chen,
S.
Malish,
and
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McMahon.
April
15,
2002.

U.
S.
EPA,
2000.
National
Primary
Drinking
water
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Arsenic
and
Clarifications
to
Regulations;
Arsenic
and
Clarifications
to
Compliance
and
New
Source
Contaminants
Monitoring
Proposed
Rule.
40
CFR
Parts
141
and
142.