Page
1
of
9
UNITED
STATES
ENVIRONMENTAL
PROTECTION
AGENCY
WASHINGTON,
D.
C.
20460
OFFICE
OF
PREVENTION,
PESTICIDES
AND
TOXIC
SUBSTANCES
May
20,
2004
Memorandum
SUBJECT:
Response
to
"
Evaluation
of
the
Potential
Exposure
of
Workers
to
Propanil
During
Mixing/
Loading
and
Aerial
Application
to
Rice
Fields
Using
Simultaneous
Dermal
Dosimetry
and
Biological
Monitoring
Techniques"
and
"
Propanil
Exposures
and
Risk
Assessment
Based
on
Data
from
an
Aerial
Application
Study
in
Rice
with
Liquid
Formulations"

FROM:
Shanna
Recore,
Industrial
Hygienist
Bill
Smith,
Environmental
Protection
Specialist
Reregistration
Branch
II
Health
Effects
Division
(
7509C)

THRU:
Al
Nielsen,
Branch
Senior
Scientist
Reregistration
Branch
II
Health
Effects
Division
(
7509C)

TO:
Carmen
Rodia,
Chemical
Review
Manager
Reregistration
Branch
Special
Review
and
Reregistration
Division
(
7508C)

DP
Barcode:
297899
PC
Code:
028201
EPA
MRID
No.:
461478­
01
Attached
is
the
Health
Effects
Division's
(
HED)
response
to
both
"
Evaluation
of
the
Potential
Exposure
of
Workers
to
Propanil
During
Mixing/
Loading
and
Aerial
Application
to
Rice
Fields
Using
Simultaneous
Dermal
Dosimetry
and
Biological
Monitoring
Techniques"
and
"
Propanil
Exposure
and
Risk
Assessment
Based
on
Data
from
an
Aerial
Application
Study
in
Rice
with
Liquid
Formulations"
submitted
by
The
Propanil
Task
Force
II
to
EPA
on
August
15,
2003
and
December
5,
2003,
respectively.
Page
2
of
9
The
Propanil
Task
Force
II
submitted
to
EPA
September
13,
2003,
a
study
titled
Evaluation
of
the
Potential
Exposure
of
Workers
to
Propanil
During
Mixing/
Loading
and
Aerial
Application
to
Rice
Fields
Using
Simultaneous
Dermal
Dosimetry
and
Biological
Monitoring
Techniques
(
MRID
#
46075501).
The
purpose
of
this
study
was
to
quantify
inhalation
and
dermal
exposure
of
handlers
during
mixing/
loading
and
aerial
application
of
propanil
to
rice
fields.
Thirty
individuals
participated
in
the
study
at
eleven
test
sites
(
15
mixer/
loaders,
14
pilots,
and
1
combined
mixer/
loader/
pilot).
The
sites
for
this
study
were
located
in
Texas,
Louisiana,
and
Arkansas
and
there
were
multiple
sites
in
each
state.

The
study
produced
propanil­
specific
biomonitoring
and
passive
dosimetry
data.
The
study
author
indicates
that
the
study
design
employs
a
"
commonly
used
technique
of
simultaneous
dosimetry
and
biological
monitoring."
The
technique
involves
the
use
of
an
outer
dosimeter
(
long­
sleeve
shirt
and
long
pants)
worn
over
an
inner
dosimeter
(
tee
shirt
and
briefs).
The
author
states
that
this
dosimetry
design
"
allows
for
penetration
of
the
propanil
residues
through
the
clothing
as
would
occur
under
normal
field
agricultural
practices,
and
does
not
block
the
penetration
of
propanil
through
the
skin
as
would
occur
if
a
long
underwear
whole
body
dosimeter
were
worn
under
the
long­
sleeve
shirt
and
long
pants."

Total
Handler
Exposure
Total
handler
exposure
was
calculated
in
the
study
through
combining
inhalation
exposures
(
measured
using
personal
air
samplers)
with
dermal
exposures
(
measured
through
passive
dosimetry
techniques).
The
dermal
passive
dosimetry
techniques
included
hand
washes,
hat
patches,
and
by
the
use
of
an
"
outer"
dosimeter
for
the
torso,
arms,
and
legs
and
an
"
inner"
dosimeter
for
the
torso.
The
study
author
compared
the
residues
on
the
inner
dosimeter
to
the
torso
residues
on
the
outer
dosimeter
and
derived
a
"
protection
factor"
attributable
to
the
outer
dosimeter.
Dermal
exposure
to
the
torso,
arms,
and
legs
was
then
estimated
by
applying
the
protection
factor
to
the
outer
dosimeter
residues.
Total
dermal
exposure
was
calculated
by
adding
the
adjusted
torso,
arms,
and
legs
exposure
to
the
hand
exposure
values
and
head/
face/
neck
exposure
values.

Total
handler
exposure
was
also
calculated
in
the
study
using
biomonitoring
techniques
 
through
analysis
of
the
handlers'
urine
for
3,4­
dichloroaniline
(
3,4­
DCA),
which
the
study
author
cites
as
the
major
metabolite
of
propanil.
The
study
protocol
required
that
handlers
participating
in
the
study
would
not
be
exposed
to
propanil
for
at
least
3
days
prior
to
and
at
least
3
days
following
the
day
of
the
study.
In
the
study
itself,
however,
only
two
handlers
out
of
the
30
participants
were
known
to
have
had
no
exposure
in
the
3
days
before
and
3
days
following
the
study.
Six
other
handlers
may
not
have
had
exposures
in
the
3
days
before
and
3
days
following
the
study,
but
there
was
some
uncertainty.
The
remaining
22
participants
were
known
to
have
had
exposures
in
one
or
more
of
the
3
days
before
and
3
days
following
the
study.
The
urine
data
collected
for
eight
handlers
who
were
presumed
to
have
had
no
propanil
exposures
for
three
days
before
or
three
days
after
the
study
were
input
into
a
model
to
determine
the
half­
life
of
the
excretion
of
detectable
urine
residues.
The
half­
life
of
the
excretion
of
propanil
metabolites
was
found
to
be
23.9
hours.
Using
a
model
to
adjust
for
propanil
residues
that
handlers
may
have
received
other
than
during
the
study,
the
study
author
calculated
an
approximate
dose
of
propanil
Page
3
of
9
for
each
handler
on
day
0.
The
study
author
calculated
unit
exposures
of
54.7
±
120
:
g/
kg
ai/
day
for
mixer/
loaders
and
35.5
:
g/
kg
ai/
day
for
pilots.
For
both
mixer/
loaders
and
pilots,
the
unit
exposure
values
obtained
from
biomonitoring
are
much
higher
than
those
obtained
from
whole
body
dosimetry.

Use
of
the
Passive
Dosimetry
Study
Data
HED
has
numerous
concerns
about
the
data
produced
by
the
study,
including:

°
The
study
protocol
states
that
"
mixer/
loaders
will
wear
new
or
freshly
laundered
longsleeved
shirts,
new
or
freshly
laundered
long
pants,
new
or
freshly
laundered
t­
shirt
and
brief,
new
chemical­
resistant
gloves,
new
shoes,
new
socks,
and
protective
eyewear
as
required
by
the
label."
However,
mixers/
loaders
in
the
study
wore
either
a
chemicalresistant
apron
or
a
Tyvek
coverall
over
the
"
outer"
dosimeter
(
cotton
coverall)
and
also
wore
chemical­
resistant
footwear.
In
calculating
potential
dermal
exposures
to
mixers/
loaders,
the
study
author
does
not
factor
in
this
additional
personal
protective
equipment,
which
exceeds
the
requirements
of
the
product
labeling.

°
The
study
states
that
most
mixers/
loaders
used
a
siphoning
device
to
transfer
the
propanil
from
the
drum
into
the
mix
tank
and
then
used
a
dry­
lock
system
(
an
engineering
control)
to
pump
the
dilute
mixture
into
the
airplane
spray
tank.
This
would
result
in
artificially
low
mixer/
loader
exposures
due
to
the
use
of
the
engineering
control
in
part
of
the
mix/
load
process.

°
The
study
protocol
states
that
"
all
workers
will
perform
their
work
tasks
for
a
typical
amount
of
time
that
represents
an
entire
workday.
One
replicate
will
be
an
entire
workday
for
each
test
subject.
.
.
.
The
air
sampling
pump
will
operate
for
the
entire
monitoring
replicate
(
estimated
to
be
6­
12
hours)."
However,
the
average
duration
of
actual
handling
for
each
replicate
in
the
study
was
only
2.2
hours
for
mixers/
loaders
and
only
1.7
hours
for
pilots.

°
The
study
protocol
states:
"
applications
of
the
test
substance
to
rice
fields
will
be
made
at
a
rate
of
6
lbs
ai/
acre."
However,
the
average
application
rate
used
in
the
study
was
approximately
2.8
pounds
active
ingredient
per
acre
 
ranging
from
1.9
to
4.5
lb
ai/
acre.

°
Overall,
there
were
thirteen
amendments
and
forty
deviations
to
the
study
protocol.

Triple
Layers
for
Mixers/
Loaders:
In
the
study
protocol,
where
the
use
of
a
protection
factor
was
presented
as
an
approach
to
calculating
exposure
to
the
torso,
arms,
and
legs,
the
study
authors
stated
that
mixers/
loaders
would
wear
new
or
freshly
laundered
long­
sleeve
shirt
and
long
pants
over
a
tee­
shirt
and
briefs.
EPA
agreed
that
such
attire
would
permit
the
calculation
of
a
penetration
factor
for
estimating
risks
to
the
torso,
arms,
and
legs.
However,
in
the
actual
study,
all
mixers/
loaders
wore
either
a
chemical­
resistant
apron
or
a
Tyvek
coverall
as
an
additional
layer
over
cotton
coveralls.
The
study
did
not
use
the
residues
on
the
apron
or
Tyvek
coveralls,
but
measured
residues
on
the
cotton
coverall
as
the
"
outer
dosimeter"
and
on
the
Page
4
of
9
tee
shirt
and
briefs
as
the
"
inner
dosimeter."
However,
the
apron
provided
a
chemical­
resistant
barrier
over
the
coverall
in
the
torso
section
and
presumably
reduced
penetration
to
the
coverall
itself
to
a
significant
degree.
Since
an
apron
would
not
provide
similar
exposure
to
the
legs
and
arms,
applying
a
penetration
factor
calculated
on
the
torso
exposures
to
the
residues
measured
on
the
arms
and
legs
would
result
in
a
calculated
penetration
factor
that
would
be
artificially
low.
Similarly,
the
Tyvek
coverall
reduced
exposure
to
the
cotton
coverall
to
a
significant
degree.
Therefore,
any
calculated
penetration
factor
also
would
be
artificially
low.
HED
considered
calculating
a
penetration
factor
using
the
Tyvek
coverall
as
the
outer
dosimeter
and
the
cotton
coverall
as
the
inner
dosimeter.
However,
only
four
mixer/
loader
replicates
were
performed
with
Tyvek
coveralls,
which
would
not
provide
a
statistically
significant
number.
In
addition,
nonwoven
fabric,
such
as
Tyvek,
is
known
to
allow
significantly
less
penetration
than
a
cotton
coverall,
therefore
a
calculated
penetration
factor
would
not
be
representative
of
the
penetration
through
cotton
coveralls.
Due
to
many
practical
considerations,
including
cost
and
heat
stress
concerns,
EPA
does
not
require
routine
use
by
mixers/
loaders
or
applicators
of
coveralls
made
from
Tyvek
or
other
nonwoven
fabrics.

Reduced
Likelihood
of
Penetration
of
Coverall:
Penetration
of
a
chemical
through
a
matrix
is
dependent
on
three
factors:
1.
composition
of
the
matrix,
2.
concentration
of
the
residue
on
the
matrix
surface,
and
3.
time
of
residue
contact
with
the
matrix
surface.
This
study
used
application
rates
lower
than
the
maximum
6
pounds
active
ingredient
listed
in
the
protocol
and
on
the
product
labeling
(
STAM
M4),
with
an
average
application
rate
in
the
study
slightly
less
than
3
pounds
active
ingredient
per
acre.
In
addition,
this
study
involved
much
lower
handling
times
than
were
listed
in
the
protocol.
The
average
actual
handling
time
for
mixers/
loaders
was
only
2.2
hours
and
for
pilots
was
only
1.7
hours
and
the
average
dermal
monitoring
time
was
less
than
4.5
hours
for
both
handling
tasks.
The
application­
rate
factor
would
be
expected
to
result
in
less
residue
being
deposited
on
the
outer
dosimeter
and
the
handling
time
factor
would
be
expected
to
result
in
less
time
for
the
residue
to
penetrate
the
outer
dosimeter.

Dermal
Exposures
to
Mixers/
Loaders
and
Pilots:
HED
used
the
propanil
passive
dosimetry
data
to
calculate
dermal
exposure
to
the
torso,
arms,
and
legs
for
the
pilot
scenarios
only.
HED
did
not
calculate
dermal
exposure
to
the
torso,
arms,
and
legs
for
the
mixer/
loader
or
for
the
mixer/
loader/
applicator
scenarios,
since
an
appropriate
protection
factor
could
not
be
calculated
from
the
data
as
presented
in
the
study.
HED
calculated
the
dermal­
body
exposure
to
pilots
using
the
same
method
as
the
study
author.
First,
a
penetration
factor
was
derived
by
dividing
the
amount
of
residue
on
the
inner
dosimeter
(
tee
shirt
and
briefs)
by
the
residue
on
the
torso
section
of
the
outer
dosimeter.
Then
outer
dosimeter
residues
for
arms,
legs,
and
torso
were
multiplied
by
the
penetration
factor.
For
the
pilot
study,
dermal
unit
exposures
averaged
1.05E­
04
mg/
lb
ai
for
the
arms,
4.82E­
05
mg/
lb
ai
for
the
legs,
and
7.46E­
05
mg/
lb
ai
for
the
torso.

HED
then
calculated
total
dermal
unit
exposure
for
pilots
by
summing
the
dermal
unit
exposures
to
hands
(
from
hand
washes),
to
face,
head,
and
neck
(
from
head
patches),
and
to
the
arms,
legs,
and
torso
(
as
described
above).
Total
dermal
unit
exposure
estimates
averaged
1.27E­
03
mg/
lb
ai
Page
5
of
9
handled
for
the
pilots.
Total
dermal
unit
exposure
to
mixers/
loaders
and
to
the
mixer/
loader/
applicator
were
not
calculated
by
HED,
since
an
appropriate
protection
factor
could
not
be
calculated
from
the
data
as
presented
in
the
study
for
dermal
exposure
to
the
torso,
arms,
and
legs
for
these
two
scenarios.

Use
of
the
Biomonitoring
Study
Data
HED
has
the
same
concerns
 
excess
PPE,
short
handling
periods,
and
low
amount
of
active
ingredient
handled
 
about
the
biomonitoring
study
data
as
for
the
passive
dosimetry
study
data.
In
addition,
HED
has
concerns
that
22
of
30
study
participants
were
known
to
have
had
propanil
exposures
in
one
or
more
of
the
3
days
before
and
3
days
following
the
study.

The
report
that
the
Propanil
Task
Force
II
submitted
to
EPA
on
December
5,
2003,
titled
"
Propanil
Exposure
and
Risk
Assessment
Based
on
Data
from
an
Aerial
Application
Study
in
Rice
with
Liquid
Formulations"
states:

Analysis
of
DCA
in
urine
was
conducted
only
as
a
marker
metabolite
to
afford
a
qualitative
indication
of
exposure
to
propanil.
DCA
is
not
a
major
metabolite,
but
the
short
term
dosing
study
in
rats
shows
that
approximately
47%
of
parent
metabolizes
into
dicarboxylic
acids
in
rats
that,
when
hydrolyzed
with
hydrochloric
acid,
are
converted
to
the
DCA
moiety.
Only
rat
metabolism
data
is
available
for
propanil.
Because
no
human
metabolism
data
exist,
urine
analysis
for
DCA
is
not
valid
as
a
tool
for
quantification
of
exposure
to
propanil,
but
is
valid
as
a
qualitative
tool
to
indicate
exposure
to
propanil.
(
Dow
AgroSciences
LLC,
Study
ID:
GH­
C
5691,
page
14­
15)

Therefore,
the
Propanil
Task
Force
II
did
not
attempt
to
use
the
biomonitoring
data
to
perform
a
quantitative
assessment
of
mixers/
loaders
and
pilots
exposures
to
propanil.

Revised
Exposure
and
Risk
Assessment
to
Pilots
Applying
Propanil
to
Rice
HED
assessed
the
exposure
and
risks
to
pilots
applying
propanil
to
rice
using
data
from
version
1.1
of
the
Pesticide
Handlers
Exposure
Database
(
which
contains
24
to
48
replicates
for
pilots
using
enclosed
cockpits)
and
using
passive
dosimetry
and
biomonitoring
data
from
the
study
(
MRID
#
46075501)
titled
Evaluation
of
the
Potential
Exposure
of
Workers
to
Propanil
During
Mixing/
Loading
and
Aerial
Application
to
Rice
Fields
Using
Simultaneous
Dermal
Dosimetry
and
Biological
Monitoring
Techniques
(
which
contains
14
replicates
for
pilots
using
enclosed
cockpits).
HED
believes
the
propanil­
specific
passive
dosimetry
study
data
represents
artificially
low
exposure
values,
due
to
the
limited
amount
of
active
ingredient
handled
by
pilots
and
the
limited
period
of
time
the
pilots
wore
the
dosimeters.
In
a
normal
work
day,
HED
believes
it
is
unlikely
that
pilots
would
change
out
of
their
work
clothes
until
the
end
of
an
8
to10­
hour
workday.
Page
6
of
9
The
results
of
the
revised
exposure
and
risk
assessment
indicate
that:

°
risks
are
not
a
concern
using
the
propanil­
specific
passive
dosimetry
data
when
applying
propanil
at
the
3
or
6
pounds
active
ingredient
per
acre
application
rate
at
up
to
3200
acres
per
day.
(
Note:
HED
believes
the
passive
dosimetry
data
represents
artificially
low
exposure
values.)

°
risks
remain
a
concern
using
the
propanil­
specific
biomonitoring
data
when
applying
propanil
at
the
3
or
6
pounds
active
ingredient
per
acre
application
rate
at
350
to
3200
acres
per
day.

°
risks
remain
a
concern
using
PHED
data
>
at
the
6
pounds
active
ingredient
per
acre
application
rate
for
scenarios,
even
when
only
350
acres
are
treated
per
day
and
>
at
the
3
pounds
active
ingredient
per
acre
application
rate
and
1200
or
3200
acres
per
day.

°
risks
are
not
a
concern
using
PHED
data
when
applying
propanil
at
the
3
pounds
active
ingredient
per
acre
application
rate
to
350
or
500
acres
per
day.

These
risks
calculated
from
the
study
passive
dosimetry
data
are
essentially
the
same
as
those
calculated
in
the
report
titled
"
Propanil
Exposure
and
Risk
Assessment
Based
on
Data
from
an
Aerial
Application
Study
in
Rice
with
Liquid
Formulations"
that
was
submitted
to
EPA
on
December
5,
2003,
by
the
Propanil
Task
Force
II.

See
table
below
 
Summary
of
Risks
to
Pilots
in
Enclosed
Cockpits
Using
PHED
and
Propanil­
Specific
Data.
Page
7
of
9
Summary
of
Risks
to
Pilots
in
Enclosed
Cockpits
Using
PHED
and
Propanil­
Specific
Data
Exposure
Scenario
Data
Sourcea
Application
Rate
(
lb
ai/
A)
Area
Treated
Dailyb
(
acres)
Engineering
Controls
(
Enclosed
Cockpits)

Dermal
Unit
Exposure
(
mg/
lb
ai)
Inhalation
Unit
Exposure
(
ug/
lb
ai)
Biomonitoring
Unit
Exposure
(
mg/
lb
ai)
Dermal
MOE
Inhalation
MOE
Dermal
+
Inhalation
MOE
Geometric
Mean
Target
MOE
=
300
Applying
Sprays
to
Rice
with
Enclosed
Cockpit
Aerial
Equipment
PHED
6
3200
0.005
0.068
N/
A
33
480
31
Propanil
Dosimetry
0.00027
0.00093
N/
A
610
35,000
600
Propanil
Biomonitoring
N/
A
N/
A
0.016
N/
A
N/
A
2.1
PHED
data
1200
0.005
0.068
N/
A
88
1300
82
Propanil
Dosimetry
0.00027
0.00093
N/
A
1600
94,000
1600
Propanil
Biomonitoring
N/
A
N/
A
0.016
N/
A
N/
A
5.5
PHED
data
500
0.005
0.068
N/
A
210
3100
200
Propanil
Dosimetry
0.00027
0.00093
N/
A
3900
230,000
3800
Propanil
Biomonitoring
N/
A
N/
A
0.016
N/
A
N/
A
13
PHED
data
350
0.005
0.068
N/
A
300
4400
280
Propanil
Dosimetry
0.00027
0.00093
N/
A
5600
320,000
5500
Propanil
Biomonitoring
N/
A
N/
A
0.016
N/
A
N/
A
19
PHED
data
3
3200
0.005
0.068
N/
A
66
970
62
Propanil
Dosimetry
0.00027
0.00093
N/
A
1200
71,000
1200
Propanil
Biomonitoring
N/
A
N/
A
0.016
N/
A
N/
A
4.1
PHED
data
1200
0.005
0.068
N/
A
180
2600
170
Propanil
Dosimetry
0.00027
0.00093
N/
A
3200
190,000
3100
Propanil
Biomonitoring
N/
A
N/
A
0.016
N/
A
N/
A
11
PHED
data
500
0.005
0.068
N/
A
420
6200
390
Propanil
Dosimetry
0.00027
0.00093
N/
A
7800
450,000
7700
Propanil
Biomonitoring
N/
A
N/
A
0.016
N/
A
N/
A
26
Exposure
Scenario
Data
Sourcea
Application
Rate
(
lb
ai/
A)
Area
Treated
Dailyb
(
acres)
Engineering
Controls
(
Enclosed
Cockpits)

Dermal
Unit
Exposure
(
mg/
lb
ai)
Inhalation
Unit
Exposure
(
ug/
lb
ai)
Biomonitoring
Unit
Exposure
(
mg/
lb
ai)
Dermal
MOE
Inhalation
MOE
Dermal
+
Inhalation
MOE
Geometric
Mean
Target
MOE
=
300
Page
8
of
9
PHED
data
350
0.005
0.068
N/
A
600
8800
560
Propanil
Dosimetry
0.00027
0.00093
N/
A
11,000
650,000
11,000
Propanil
Biomonitoring
N/
A
N/
A
0.016
N/
A
N/
A
38
Footnotes:

a
PHED
data
is
from
version
1.1
of
the
Pesticide
Handlers
Exposure
Database;
Propanil
Data
is
from
the
Propanil
Study
Evaluation
of
the
Potential
Exposure
of
Workers
to
Propanil
During
Mixing/
Loading
and
Aerial
Application
to
Rice
Fields
Using
Simultaneous
Dermal
Dosimetry
and
Biological
Monitoring
Techniques
dated
September,
13,
2003.

b
Acres
treated
daily:
3200
acres
was
the
high
end
estimate
for
rice
provided
by
the
Propanil
Task
Force
at
the
SMART
Meeting
that
occurred
on
March
23,
2001,

1200
acres
per
day
is
the
default
acres
treated
for
rice
under
Policy
9
of
the
Science
Advisory
Council
for
Exposure
(
06/
23/
2000)
titled
"
Standard
Values
for
Daily
Acres
Treated
in
Agriculture,"
and
500
acres
and
300
acres
are
presented
for
rangefinder
purposes.
Page
9
of
9
