Document ID: EPA-HQ-OPP-2005-0263-0003
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2005-10-26T18:41:26Z

Page
1
of
13
UNITED
STATES
ENVIRONMENTAL
PROTECTION
AGENCY
OFFICE
OF
PREVENTION,
PESTICIDES,
AND
TOXIC
SUBSTANCES
WASHINGTON,
D.
C.
20460
October
19,
2005
MEMORANDUM
SUBJECT:
MCPB:
Revised
Occupational
and
Residential
Exposure
and
Risk
Assessment
for
the
Reregistration
Eligibility
Decision
(
RED)
PC
Code:
019201
(
MCPB
Acid)
and
019202
(
MCPB
Sodium
Salt)
DP
Barcode:
D314051
FROM:
Timothy
C.
Dole,
CIH,
Industrial
Hygienist
Reregistration
Branch
I
Health
Effects
Division
(
7509C)

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

TO:
James
Parker,
Chemical
Review
Manager
Reregistration
Branch
I
Special
Review
and
Reregistration
Division
(
7508C)

Attached
is
the
Revised
Occupational
and
Residential
Exposure
and
Risk
Assessment
for
the
MCPB
HED
RED
Chapter.
This
assessment
has
been
revised
as
appropriate
to
address
Error
Only
Comments
that
were
submitted
by
MCPB
Task
Force
on
9/
23/
2005
and
9/
29/
2005.

Expo
Sac
Reviewer:
Matt
Crowley
Page
2
of
13
Executive
Summary
3
1.0
Background
Information
5
1.1
Purpose
and
Criteria
for
Conducting
Exposure
Assessments
5
1.2
Toxicological
Endpoints
5
1.3
Incident
Reports
6
1.4
Summary
of
Use
Patterns,
Formulations
and
Application
Methods
6
2.0
Occupational
and
Residential
Exposures
and
Risks
9
2.1
Occupational
Handler/
Applicator
Exposures
&
Risks
9
2.1.1
Exposure
Scenarios
9
2.1.2
Exposure
Assumptions
and
Data
Sources
9
2.1.3
Exposure
and
Risk
Estimates
10
2.1.4
Risk
Characterization
10
2.2
Occupational
Post­
Application
Exposures
&
Risks
11
2.2.1
Exposure
Scenarios
11
2.2.2
Exposure
Data
Sources,
Assumptions
and
Transfer
Coefficients
11
2.2.3
Exposure
and
Risk
Estimates
12
2.2.4
Risk
Characterization
12
3.0
Information
Sources
12
4.0
Glossary
of
Terms
13
Appendices
A
­
Standard
Formulas
Used
for
Calculating
Occupational
Exposures
to
MCPB
A­
1
B
­
Occupational
Handler
Exposure
Data
and
Risk
Calculations
for
MCPB
B­
1
C
­
Occupational
Post­
Application
Risks
of
MCPB
C­
1
Page
3
of
13
Executive
Summary
MCPB
Product
Descriptions,
Uses
and
Application
Methods:

MCPB
[
4­(
2­
methyl­
4
­
chlorophenoxy)
butyric
acid]
is
a
phenoxy
herbicide
that
is
produced
as
an
acid
and
as
sodium
salt.
It
is
used
only
on
peas
and
one
application
is
typically
made
per
growing
season.
The
are
no
residential
uses
of
MCPB.
The
MCPB
labels
allow
ground
and
aerial
application,
however,
they
do
not
allow
chemigation.

Toxicology
Endpoints:

The
toxicity
database
for
MCPB
was
limited
and
was
supplemented
with
the
closely
related
compound,
MCPA.
The
following
endpoints
were
used
for
assessing
MCPB
occupational
risks:

A
dermal
NOAEL
of
100
mg/
kg/
day
was
selected
from
a
21
day
dermal
toxicity
study
using
MCPA
during
which
kidney
toxicity
and
decreased
body
weight
gain
were
observed
with
a
LOAEL
of
1000
mg/
kg/
day.
This
endpoint
is
applicable
to
short
and
intermediate
term
dermal
exposures.

An
oral
NOAEL
of
5
mg/
kg/
day
was
selected
from
a
rabbit
developmental
toxicity
study
using
MCPB
during
which
clinical
signs
and
maternal
mortality
were
observed
in
the
dams
with
a
LOAEL
of
20
mg/
kg/
day.
This
endpoint
is
applicable
to
short
and
intermediate
term
inhalation
exposures.

Endpoints
were
also
selected
for
chronic
exposures,
however,
these
endpoints
were
not
used
in
this
assessment
because
chronic
occupational
exposures
to
MCPB
would
not
be
expected
to
occur.
MCPB
is
only
applied
once
during
the
growing
season
and
rapidly
dissipates
from
the
foliage.

The
target
Margin
of
Exposure
(
MOE)
for
occupational
populations
is
100,
which
includes
the
standard
safety
factors
of
10X
for
intraspecies
variability
(
i.
e.
differences
among
humans)
and
10X
for
interspecies
variability
(
differences
between
humans
and
animals).

Acute
toxicity
data
indicates
that
MCPB
is
of
low
to
moderate
toxicity
via
the
oral,
inhalation
or
dermal
routes
of
exposure.
It
causes
mild
to
moderate
eye
irritation.
It
is
non­
irritating
to
the
skin
and
it
is
not
a
dermal
sensitizer.

Occupational
Handler/
Applicator
Exposure
and
Risk
Estimates:

The
MOEs
for
occupational
exposures
were
calculated
for
short/
intermediate
term
dermal
and
inhalation
exposures.
These
MOEs
were
calculated
separately
because
the
dermal
and
inhalation
endpoints
were
based
upon
different
effects.
Standard
assumptions,
PHED
unit
exposure
data
and
maximum
label
rates
were
used.
All
of
the
inhalation
MOEs
exceed
the
target
of
100
with
baseline
respiratory
protection
(
i.
e.
no
respirators
worn)
and
are
not
of
concern.
All
of
the
Page
4
of
13
dermal
MOEs
exceed
the
target
MOE
with
single
layer
PPE
for
mixer/
loaders
and
baseline
PPE
for
applicators.

Post­
Application
Occupational
Exposure
and
Risk
Estimates:

Post­
application
exposure
to
re­
entry
workers
is
possible
because
MCPB
can
be
applied
over
the
top
to
peas.
Post­
application
activities
including
irrigation
and
scouting,
which
can
result
in
dermal
exposures.
The
exposures
were
assessed
using
standard
assumptions
and
the
maximum
label
rate.
All
of
the
post­
application
MOEs
are
above
the
target
MOE
of
100
on
Day
0.

Risk
Characterization
This
assessment
was
conducted
using
the
maximum
rate
of
1.5
lb
ae/
acre.
Typical
rates
are
lower
particularly
if
MCPB
is
tank
mixed
with
Basagram.

Many
of
the
labels
require
waterproof
gloves
instead
of
chemical
resistant
gloves.
It
is
not
known
if
these
gloves
provide
adequate
protection.
It
is
recommended
that
mixers
and
loaders
wear
gloves
made
of
chemically
resistant
and
waterproof
material
when
handling
MCPB.
Page
5
of
13
1.0
Background
Information
1.1
Purpose
and
Criteria
for
Conducting
Exposure
Assessments
Occupational
and
residential
exposure
and
risk
assessments
are
required
for
an
active
ingredient
if:
(
1)
certain
toxicological
criteria
are
triggered
and
(
2)
there
is
potential
exposure
to
handlers
during
use,
or
to
field
workers
entering
treated
areas
after
application
is
completed.
MCPB
[
4­(
2­
methyl­
4­
chlorophenoxy)
butyric
acid];
CAS
#
94­
81­
5
meets
both
criteria.
There
is
potential
exposure
to
handlers
and
field
workers
from
agricultural
site
applications
of
MCPB.

1.2
Toxicological
Endpoints
A
summary
of
the
acute
toxicity
test
results
is
included
in
Table
1.
These
results
indicate
that
MCPB
is
of
low
to
moderate
toxicity
via
the
oral,
inhalation
or
dermal
routes
of
exposure.
MCPB
causes
mild
to
moderate
eye
irritation.
MCPB
is
non­
irritating
to
the
skin
and
is
not
a
dermal
sensitizer.

Table
1
­
Acute
Toxicity
of
MCPB
Guideline
No.
Study
Type
MRID
Results
Toxicity
Category
870.1100
870.1100
Acute
oral
­
rat
Acute
oral
­
rat
116340
144801
LD50
=
1570
mg/
kg
LD50
=
4300
mg/
kg
III
III
870.1200
870.1200
Acute
dermal
­
rabbit
Acute
dermal
­
rat
116342
144799
LD50
>
10000
mg/
kg
LD50
>
2000
mg/
kg
IV
II
870.1300
Acute
inhalation
­
rat
416300­
01
LC50
>
1.14
mg/
L
III
870.2400
870.2400
Acute
eye
irritation
­
rabbit
Acute
eye
irritation
­
rabbit
116343
144797
Moderately
irritating
Mildly
irritating
II
III
870.2500
Acute
dermal
irritation
­
rabbit
144798
Non­
irritating
IV
870.2600
Skin
sensitization
­
guinea
pig
144800
Negative
IV
Because
the
toxicity
database
for
MCPB
was
limited,
studies
with
the
closely
related
compound,
MCPA
were
used
to
select
some
of
the
toxicity
endpoints.
The
endpoints
that
were
used
to
complete
occupational
exposure
assessments
are
summarized
in
Table
2.

The
target
Margin
of
Exposure
(
MOE)
for
occupational
populations
is
100,
which
includes
the
standard
safety
factors
of
10X
for
intraspecies
variability
(
i.
e.
differences
among
humans)
and
10X
for
interspecies
variability
(
differences
between
humans
and
animals).
Although
there
are
no
residential
uses
of
MCPB,
it
is
worth
noting
that
the
target
MOE
for
residential
populations
is
300,
because
an
FQPA
factor
of
3
is
required
for
database
uncertainty
due
to
a
lack
of
a
Page
6
of
13
developmental
nuerotoxicity
study.

In
accordance
with
the
1999
Draft
Guidelines
for
Cancer
Risk
Assessment
(
July,
1999),
the
HIARC
classified
MCPB
as
"
not
likely
to
be
carcinogenic
to
humans".
This
classification
was
based
on
the
lack
of
evidence
of
carcinogenicity
in
mice
and
rats.

Table
2
­
MCPB
Toxicological
Endpoints
Used
for
Occupational
Risk
Assessment
Exposure
Scenario
Dose
or
Factor
Used
in
Risk
Assessment
Study
and
Toxicological
Effects
Dermal
Short/
Intermediate
term
Dermal
NOAEL
=
100
mg/
kg/
day
21
day
dermal
toxicity
study
(
MCPA).
LOAEL
=
1000
mg/
kg/
day
based
upon
kidney
toxicity
and
decreased
body
weight
gain.

Dermal
Long­
term
Oral
NOAEL=
4.4
mg/
kg/
day*
Chronic
toxicity
study
in
rats
(
MCPA).
LOAEL
=
17.6
mg/
kg/
day
based
on
liver
and
kidney
toxicity.

Inhalation
Short/
Intermediate
term
Oral
NOAEL
=
5.0
mg/
kg/
day*
Developmental
toxicity
in
rabbits
(
MCPB).
LOAEL
=
20
mg/
kg/
day
based
upon
clinical
signs
and
maternal
mortality.

Inhalation
long­
term
Oral
NOAEL=
4.4
mg/
kg/
day*
Chronic
toxicity
study
in
rats
(
MCPA).
LOAEL
=
17.6
mg/
kg/
day
based
on
liver
and
kidney
toxicity.

Dermal
Absorption
Factor
7
percent
Dermal
absorption
study
in
rats
with
MCPA.

Uncertainty
Factor
for
Occupational
Exposures
100
Includes
standard
factors
of
10
and
10
for
intraspecies
variability
and
interspecies
extrapolation.

*
Since
an
oral
NOAEL
was
selected,
a
dermal
absorption
factor
should
be
used
in
route
to
route
extrapolation.
+
Inhalation
absorption
is
assumed
to
be
equivalent
to
oral
absorption
(
100
percent
default
value).

1.3
Incident
Report
The
incident
report
is
being
prepared
under
a
separate
memo
by
Monica
Spann,
M.
P.
H.
and
Jerome
Blondell,
PhD.
of
the
Office
of
Pesticide
Programs.

1.4.
Summary
of
Use
Patterns,
Formulations
and
Application
Methods
Uses
Based
upon
the
MCPB
product
labels,
MCPB
is
intended
only
for
agricultural
applications
on
peas.
There
are
no
residential
uses
of
MCPB.
Page
7
of
13
Mode
of
Action
and
Targets
Controlled
According
to
the
product
labels,
MCPB
provides
postemergence
control
of
weeds
such
as
Canada
thistle
(
which
is
a
particularly
troublesome
weed
in
pea
fields)
as
well
as
other
broadleaf
weeds
such
as
common
lambsquarters,
pigweed,
smartweed,
sowthistle
and
morningglories.
According
to
the
Farm
Chemicals
Handbook
(
Meister
2002),
MCPB
is
oxidized
to
MCPA
in
susceptible
plants.

Formulation
Types
and
Percent
Active
Ingredient
According
to
EPA
OPPIN
tracking
system,
as
of
07/
05/
05,
there
are
3
active
end
use
products
of
MCPB
formulated
from
two
technical
products.
The
technical
products
are
the
acid
form
of
MCPB
and
the
end
use
products
are
the
sodium
salt
form
of
MCPB
(
Table
3).
All
of
the
products
are
formulated
as
liquids.

Table
3
­
MCPB
Forms
and
Number
of
End
Use
Product
Labels
MCPB
Form
PC
CODE
Number
of
Product
Labels
Formulation
Other
Formulations
Acid
019201
2
Technical
None
Sodium
Salt
019202
3
Liquids
None
Application
Rates,
Timing
and
Frequency
of
Applications
The
labels
indicate
that
MCPB
applications
can
be
made
to
peas
from
shoot
emergence
until
about
3
leaf
nodes
before
flowering
and
pea
plants
typically
have
6
to
12
nodes
at
the
normal
time
of
Canada
thistle
treatment.
Applications
cannot
be
made
later
than
3
nodes
before
pea
flowering
or
after
pea
flower
buds
appear.

The
application
rates
as
taken
from
labels
are
included
in
Table
4
and
are
given
in
terms
of
acid
equivalent
(
ae)
which
are
based
upon
the
molecular
weight
of
the
acid
excluding
the
sodium
salt.
These
rates
range
from
0.5
to
1.5
lbs
ae/
acre
depending
on
the
leaf
stage
of
the
target
weed
and
the
use
in
tanks
mixes
with
Basagran.
The
highest
rate
is
applied
when
MCPB
is
used
alone
to
treat
Canada
thistle
that
has
reached
the
bud
stage.

The
Screening
Level
Usage
Analysis
(
SLUA)
from
BEAD
indicates
that
percent
crop
treated
is
10
percent
as
an
average
and
15
percent
as
a
maximum.
Use
data
from
the
USDA
National
Agricultural
Statistics
Service
(
NASS)
indicate
that
the
average
rate
applied
is
0.59
lb
ae/
acre
for
the
major
pea
growing
states.
Page
8
of
13
Table
4
­
MCPB
Application
Rates
Crop
Acid
Equivalent
Application
Rates
Per
Application
(
lb
ae/
acre)

Minimum
Application
Rate
Max
Label
Application
Rate
Average
Rate1
Percent
Crop
Treated2
Peas
0.5
1.5
0.59
10
to
15
Notes
1.
Based
upon
NASS
Data
for
Peas,
Green,
Processing
from
1994
to
2002.
States
included
are
MN,
NY,
OR,
WA
and
WI.
2.
PCT
is
from
MCPB
SLUA
Report
of
April
19,
2005.
This
report
includes
usage
data
from
1998
to
2003.

Other
Sources
of
Use
Information
The
Phenoxy
Herbicide
NAPIAP
report
(
Burnside
et.
al.
1996)
has
some
information
regarding
the
use
of
MCPB.
This
is
summarized
in
Table
5.

Table
5
­
MCPB
Use
Information
in
the
Phenoxy
Herbicide
NAPIAP
Report
Use
Site
NIPIAP
Findings
Peas
MCPA
and
MCPB
are
the
most
effective
for
herbicides
for
many
of
the
broadleaf
weeds
found
in
pea
such
as
common
lambsquarters
and
Canada
thistle.

Application
Methods
The
MCPB
labels
allow
ground
and
aerial
application,
however,
they
do
not
allow
chemigation.
A
listing
of
application
methods
and
amounts
of
acreage
treated
per
8
hour
day
is
presented
in
Table
6.

Table
6
­
MCPB
Application
Methods
Application
Method
Typical
Crops
Treated
Treated
Areaa
1
­
Groundboom
peas
200
2
­
Fixed
Wing
Aircraft
peas
350
a.
Based
upon
HED
ExpoSAC
SOP
#
9
"
Standard
Values
for
Daily
Acres
Treated
in
Agriculture",
Revised
July
5,
2000
Page
9
of
13
2.0
Occupational
Exposures
and
Risks
As
discussed
above,
MCPB
is
used
only
in
the
agricultural
environment.
The
risks
of
mixing,
loading
and
applying
MCPB
are
discussed
in
section
2.1.
Post­
application
exposures
and
risks
are
discussed
in
section
2.2.

2.1
Occupational
Handler/
Applicator
Exposures
&
Risks
2.1.1
Exposure
Scenarios
Based
upon
the
application
methods
shown
in
Table
6,
the
following
exposure
scenarios
were
assessed.

Mix/
Load
Liquid
Formulations
Aerial
Application
Groundboom
Application
Flag
Aerial
Application
2.1.2
Occupational
Handler
Exposure
Assumptions
and
Data
Sources
Exposure
Assumptions
The
following
assumptions
and
factors
were
used
in
order
to
complete
the
exposure
and
risk
assessments
for
occupational
handlers/
applicators:

The
average
work
day
was
8
hours.

The
daily
acreage
treated
was
taken
from
EPA
Science
Advisory
Council
for
Exposure
Standard
Operating
Procedure
#
9
"
Standard
Values
for
Daily
Acres
Treated
in
Agriculture,"
Revised
July
5,
2000.
These
values
are
listed
in
Table
7.

The
maximum
label
application
rate
was
used
to
assess
short/
intermediate
term
risks
because
it
is
possible
that
these
rates
could
be
used
for
one
to
thirty
consecutive
days.

A
body
weight
of
70
kg
was
assumed
because
the
endpoint
is
not
gender
specific.

The
inhalation
absorption
rate
is
100%.

Baseline
PPE
includes
long
sleeve
shirts,
long
pants
and
no
gloves
or
respirator.

Single
Layer
PPE
includes
baseline
PPE
with
chemical
resistant
gloves.

Aerial
applicators
utilize
closed
cockpit
aircraft
and
do
not
wear
chemical
resistant
gloves.

Exposure
Data
Sources
Exposure
analyses
were
performed
using
the
Pesticide
Handlers
Exposure
Database
(
PHED)
as
tabulated
in
the
PHED
Surrogate
Exposure
Guide
of
August
1998.
A
description
of
PHED
is
included
in
Appendix
A.
The
unit
exposure
values
calculated
by
PHED
generally
range
from
the
geometric
mean
to
the
median
of
the
selected
data
set.

2.1.3
Occupational
Handler
Exposure
and
Risk
Estimates
Page
10
of
13
Calculation
Methodology
and
Equations
Handler
risk
(
i.
e.
MOEs)
were
calculated
as
described
in
Appendix
A.
The
basic
rationale
for
these
calculations
is
that
the
daily
exposure
is
the
product
of
the
amount
of
ai
handled
per
day
times
a
unit
exposure
value.
The
MOEs
were
calculated
for
short/
intermediate
term
dermal
and
inhalation
exposures.
These
MOEs
were
calculated
separately
because
the
dermal
and
inhalation
endpoints
were
based
upon
different
effects.
The
target
MOEs
are
100.
Scenarios
with
an
MOE
less
than
100
indicate
a
risk
of
concern.

Results
and
Comparison
to
Target
MOE
The
MOEs
for
handlers
are
summarized
in
Table
7
and
detailed
calculations
are
presented
in
Appendix
B.
All
of
the
dermal
MOEs
are
greater
than
100
if
single
layer
PPE
is
worn.
All
of
the
inhalation
MOEs
are
greater
than
100
with
baseline
PPE
(
i.
e.
respirators
are
not
needed).

Table
7
­
MCPB
MOEs
for
Handlers
(
Short/
Intermediate
Term
Dermal
and
Inhalation)

Exposure
Scenario
Crop
Application
Rate
(
lb
ae/
acre)
Acres/
Day
Baseline
Dermal
MOE
Single
Layer
Dermal
MOE
Baseline
Inhalation
MOE
Mix/
Load
Liquids
for
Aerial
Peas
1.5
350
5
580
560
Mix/
Load
Liquids
for
Groundboom
Peas
1.5
200
8
1000
970
Aerial
Application
Peas
1.5
350
2700
N/
A
9800
Groundboom
Application
Peas
1.5
200
1700
1700
1600
Flag
Aerial
Application
Peas
1.5
350
1200
1100
1900
2.1.4
Occupational
Handler
Risk
Characterization
This
assessment
was
conducted
using
the
maximum
rate
of
1.5
lb
ae/
acre.
The
average
rate
is
0.59
lb
ae/
acre
as
reported
by
NASS.

The
product
labels
require
waterproof
gloves
instead
of
chemical
resistant
gloves.
It
is
not
known
if
these
gloves
provide
adequate
protection.
It
is
recommended
that
mixers
and
loaders
wear
gloves
made
of
chemically
resistant
and
waterproof
material
when
handling
MCPB.

2.2
Occupational
Post­
Application
Exposure
and
Risks
Page
11
of
13
Post­
application
MCPB
exposures
can
occur
when
workers
enter
pea
fields
recently
treated
with
MCPB
to
conduct
tasks
such
as
scouting
and
irrigation.
MCPB
applications
cannot
be
made
after
pea
flower
buds
appear
and
peas
are
harvested
mechanically
approximately
three
weeks
after
bloom
(
USDA,
2002),
thus
worker
exposures
during
harvesting
are
not
anticipated.

2.2.1
Occupational
Post­
Application
Exposure
Scenarios
Because
MCPB
is
typically
applied
once
per
season,
it
is
anticipated
that
MCPB
exposures
would
be
of
short/
intermediate
term
duration
and
long
term
exposures
were
not
assessed
Potential
inhalation
exposures
are
not
anticipated
for
the
post­
application
worker
scenarios
because
of
the
low
vapor
pressure
of
MCPB
(
7.1e­
07
mm
Hg
at
23.6o
C).
As
a
result,
only
dermal
exposures
were
evaluated
in
the
post­
application
worker
assessment.

2.2.2
­
Exposure
Data
Sources,
Assumptions
and
Transfer
Coefficients
Data
Sources:

There
were
no
data
submitted
for
MCPB,
therefore,
standard
values
and
assumptions
were
used
as
discussed
below.

Assumptions
The
following
assumptions
were
made
regarding
occupational
post­
application:

The
maximum
application
rates
were
used.

The
transfer
coefficients
are
from
an
interim
transfer
coefficient
policy
developed
by
HED's
Science
Advisory
Council
for
Exposure
using
proprietary
data
from
the
Agricultural
Re­
entry
Task
Force
(
ARTF)
database
(
US
EPA,
August
7,
2001).

The
initial
percent
of
application
rate
as
Dislodgeable
Foliar
Residue
(
DFR)
was
assumed
to
be
20%
for
all
crops.
This
a
standard
value.

Calculation
Methodology
for
Post­
Application
Exposures
The
calculations
used
to
estimate
the
exposures
for
the
post­
application
scenarios
are
similar
to
those
described
previously
for
the
handler/
applicator
scenarios
and
are
described
in
Appendix
A.
Daily
dermal
exposure
is
calculated
by
multiplying
the
residue
level
(
ug/
cm2
of
leaf
area)
times
a
transfer
coefficient
(
amount
of
leaf
area
contacted
per
unit
time).
The
MOEs
are
then
calculated
using
the
short/
intermediate­
term
dermal
NOAEL.
Page
12
of
13
2.2.3
Occupational
Post­
Application
Exposure
and
Risk
Estimates
A
summary
of
the
worker
risks
for
post­
application
exposures
is
given
in
Table
8,
and
the
calculations
are
included
in
Appendix
C.
All
of
the
MOEs
are
above
100
on
Day
0
which
indicates
that
the
risks
are
not
of
concern.

Table
8
­
MCPB
Post­
Application
Worker
Risks
Crop
Application
Rate
(
lb
ae/
acre)
Task
Transfer
Coefficient
(
cm2/
hr)
Day
0
Dermal
MOE
Peas
1.5
Irrigation,
scouting,
immature
plants
Scouting
mature
plants
100
1500
2600
170
2.2.4
Occupational
Post­
Application
Risk
Characterization
This
assessment
was
conducted
using
the
maximum
rate
of
1.5
lb
ae/
acre.
Typical
rates
are
lower
particularly
if
MCPB
is
tank
mixed
with
Basagram.

3.0
Information
Sources
Burnside,
Oliver
C.
et
al,
Biologic
and
Economic
Assessment
of
Benefits
from
Use
of
Phenoxy
Herbicides
in
the
United
States,
National
Agricultural
Pesticide
Impact
Assessment
Program
(
NAPIAP)
Report
Number
1­
PA­
96,
November
1996
U.
S.
D.
A,
January
2002.
Crop
Profile
for
Peas
in
Minnesota
U.
S.
EPA,
1998.
PHED
Surrogate
Exposure
Guide,
V1.1.
U.
S.
Environmental
Protection
Agency,
Office
of
Pesticide
Programs,
August
1998.

U.
S.
EPA,
1999,
"
Use
of
Values
from
the
PHED
Surrogate
Table
and
Chemical­
Specific
Data."
Science
Advisory
Council
for
Exposure,
Policy.
007,
U.
S.
Environmental
Protection
Agency,
Office
of
Pesticide
Programs.

U.
S.
EPA,
August
7,
2000,
"
Agricultural
Default
Transfer
Coefficients"
Science
Advisory
Council
for
Exposure,
SOP
003.1,
.
U.
S.
Environmental
Protection
Agency,
Office
of
Pesticide
Programs.

U.
S.
EPA,
July
5,
2000,
"
Standard
Values
for
Daily
Acres
Treated
in
Agriculture"
HED
Science
Advisory
Council
for
Exposure,
Policy.
009,
U.
S.
Environmental
Protection
Agency,
Office
of
Pesticide
Programs.

U.
S.
EPA,
July
27,
2001
"
R.
E.
D.
Use
Profile
Report
For
MCPB
dimethylamine
salt"

U.
S.
EPA,
April
19,
2005,
Screening
Level
Estimates
of
Agricultural
Uses
of
MCPB.
Page
13
of
13
4.0
Glossary
of
Terms
Used
in
Occupational/
Residential
Exposure
Assessment
TERM
DEFINITION
AE
­
Acid
Equivalent
The
weight
of
MCPB
excluding
the
weight
of
the
amine
salt
group.

Baseline
PPE
Includes
long
pants,
long
sleeved
shirt,
shoes,
socks
and
no
gloves
or
respirator
Dose
The
amount
of
pesticide
that
is
absorbed
into
the
body.

ExpoSac
­
Scientific
Advisory
Committee
for
Exposure
A
committee
within
the
EPA
Health
Effects
Division
that
reviews
pesticide
exposure
assessments
and
develops
policy.

Exposure
The
amount
of
pesticide
that
impinges
upon
the
skin
or
is
inhaled.

Handler/
Applicator
A
worker
who
mixes,
loads
and/
or
applies
pesticides
HED
Health
Effects
Division
of
the
Office
of
Pesticide
Programs
Intermediate­
term
31
days
to
six
months
MOE
­
Margin
of
Exposure
The
ratio
of
the
NOAEL
or
LOAEL
from
animal
studies
divided
by
the
estimated
human
exposure.
Formerly
called
the
Margin
of
Safety.

NOAEL
No
Observed
Adverse
Effect
Level
PHED
Pesticide
Handlers
Exposure
Database
Re­
entry
Worker
One
who
works
in
fields
that
have
been
treated
with
pesticides
REI
­
Restricted
Entry
Interval
The
period
of
time
that
must
pass
following
pesticide
application
before
workers
are
allowed
to
re­
enter
the
treated
area.

Short­
term
One
to
thirty
days
Single
Layer
PPE
Includes
baseline
PPE
with
chemical
resistant
gloves