Page
1
of
4
UNITED
STATES
ENVIRONMENTAL
PROTECTION
AGENCY
WASHINGTON,
D.
C.
20460
OFICE
OF
PREVENTION,
PESTICIDES
AND
TOXIC
SUBSTANCES
July
5,
2006
MEMORANDUM
SUBJECT:
Piperonyl
Butoxide:
Addendum
to
Occupational
and
Residential
Exposure
Assessment:
DP
Barcode
D327790
FROM:
Becky
Daiss
Environmental
Health
Scientist
Reregistration
Branch
4/
HED
(
7509C)

THROUGH:
Susan
Hummel
Branch
Senior
Scientist
Reregistration
Branch
4/
HED
(
7509C)

TO:
Cathryn
O'Connell
Chemical
Review
Manager
Reregistration
Branch
2
Reregistration
Division
(
7505C)

This
addendum
provides
quantitative
assessments
for
exposures
to
piperonyl
butoxide
from
1)
indoor
metered
release
systems,
2)
indoor
application
of
piperonyl
butoxide
with
handheld
fogging
equipment,
and
3)
mixing
loading
and
applying
piperonyl
butoxide
for
forrest
management.
It
also
characterizes
potential
risks
from
long
term
application
of
piperonyl
butoxide
by
Pesticide
Control
Operators
(
PCO).
Page
2
of
4
Indoor
Residential
Metered
Release
Misters
Absent
exposure
data
for
these
uses,
indoor
concentrations
of
piperonly
butoxide
resulting
from
the
use
of
the
compact
metered
release
units
in
homes
were
modeled
using
MCCEM.
Single
chamber
modeling
was
used
to
determine
the
air
concentrations
that
would
result
from
a
whole
house
installation
of
multiple
compact
units.
Multi­
zone
modeling
was
used
to
determine
the
air
concentrations
that
would
result
from
the
installation
of
a
compact
unit
in
one
room
of
the
house
such
as
the
kitchen.
In
both
cases
the
emissions
source
was
defined
in
the
data
entry
screen
of
MCCEM
as
one
emission
that
lasts
for
a
minute
and
which
occurs
every
fifteen
minutes.
The
emission
rates
were
111
mg/
hr
for
one
minute
for
the
whole
house
scenario
and
46
mg/
hr
for
one
minute
for
the
kitchen
only
scenario
(
MCCEM
requires
that
the
emission
be
expressed
as
units
per
hour).
Because
the
units
run
continuously
for
thirty
days
before
the
cartridge
needs
to
be
changed,
it
is
assumed
that
exposures
could
occur
at
steady
state
concentrations,
therefore,
the
steady
state
concentrations
were
used
for
exposure
assessment.
The
piperonyl
butoxide
short/
intermediate
term
MOEs
for
indoor
residential
metered
release
(
i.
e.
aerosol
dispensers)
range
from
12
to
240.
Estimated
MOEs
for
this
scenario
are
all
below
the
target
MOE
of
300.

Piperonyl
Butoxide
Residential
Post­
Application
Inhalation
Risks
Following
Metered
Release
Exposed
Population
MCCEM
Execution
Mode
Application
Rate
(
lb
ai/
1000
cf/
day)
Initial
Concentration
(
mg/
m3)
Air
Changes
per
HourF
Steady
State
Air
Concentration
(
mg/
m3)
Inhalation
ExposureJ
(
mg/
day)
Inhalation
DoseK
(
mg/
kg/
day)
Short/
Intemediate
Term
MOEL
Adults
5.7
0.081
50
Children
0.0001375A
0.0225C
0.18
0.54G
4.7
0.313
12
Adults
3.0
0.042
90
Children
Single
Chamber
0.0001375A
0.0225C
0.45
0.225G
1.95
0.130
30
Adults
2.85
0.041
100
Children
0.00075B
1.25
KitchenD
<
0.0005
ROHE
0.18
0.050
KitchenH
0.190
ROH
0.215
TWAI
1.85
0.123
30
Adults
1.15
0.016
240
Children
Use
Interzonal
Air
Flow
Rates
0.00075B
0.025
KitchenD
<
0.0005
ROHE
0.45
0.021
KitchenH
0.070
ROH
0.085
TWAI
0.75
0.050
80
A.
The
application
rates
are
based
upon
the
Clean
Air
Purge
II
Label
(
9444­
161).
This
product
contains
1%
Pyrethrins
by
weight
in
a
232
gram
container.
One
container
will
apply
3000
sprays
per
month
at
fifteen
minute
intervals
and
is
sufficient
for
a
6000
cf
interior
space.
B.
Based
on
the
use
of
Clean
Air
Purge
II
in
the
MCCEM
generic
kitchen
which
has
an
interior
volume
of
1060
cubic
feet.
C.
Initial
concentration
for
whole
house
treatment
is
0.77
mg
per
6000
cubic
feet
converted
to
mg/
m3
(
6000
cf
=
170
m3)
D.
Initial
concentration
for
kitchen
treatment
is
0.77
mg
per
1060
cubic
feet
converted
to
mg/
m3
(
1060
cf
=
30m3)
E.
ROH
=
Rest
of
House
excluding
the
kitchen.
F.
The
MCCEM
air
change
rates
per
hour
are
0.18
for
the
average
summer
house
and
0.45
for
the
average
fall/
spring
house.
G.
Is
the
average
concentration
at
steady
state
and
was
calculated
using
MCCEM
in
single
chamber
mode.
H.
Calculated
using
MCCEM
in
multi­
zone
mode
with
the
kitchen
as
zone
one
and
the
rest
of
house
(
ROH)
as
zone
two.
I.
The
time
weighted
average
(
TWA)
concentration
is
based
upon
2
hours
per
day
in
the
kitchen
and
22
hours
per
day
in
the
rest
of
the
house.
J.
Inhalation
Exposure
(
mg/
day)
=
Steady
state
air
concentration
(
mg/
m3)
*
breathing
rate
(
13.3
m3/
day
for
adults
and
8.7
m3/
day
for
children)
K.
Inhalation
Dose
(
mg/
kg/
day)
=
Inhalation
Exposure
(
mg/
day)
/
BW
(
70
kg
for
adults
and
15
kg
for
children)
L.
MOE
=
NOAEL/
Dose;
where
the
NOAEL
is
3.91
mg/
kg/
day
for
short/
intermediate
term
exposures.
Page
3
of
4
Thermal/
Cold
Foggers
Used
for
Indoor
Applications
Lacking
exposure
data
for
these
uses,
HED
conducted
a
quantitative
assessment
of
exposure
and
risk
for
this
scenario
using
label
application
rates
and
the
following
assumptions.

­
master
label
rate
of
0.002
lb
ai/
1000
ft3
for
piperonyl
butoxide
is
applied
to
an
indoor
space.
­
ventilation
system
is
turned
off
during
application.
­
applicator
spends
4
hours
per
day
setting
up
and
4
hours
per
day
fogging.
­
applicator
is
exposed
to
master
label
rates
while
fogging.
­
breathing
rate
is
16.7
liters
per
hour.

Based
on
this
assessment,
the
daily
piperonyl
butoxide
dose
is
1.93
mg/
kg/
day.
The
NOAEL
is
3.91
mg/
kg/
day.
The
resulting
MOE
is
2
which
is
significantly
less
than
the
target
MOE
of
300.
This
assessment
indicates
that
the
applicator
should
either
operate
the
fogger
from
outside
the
treatment
area
or
wear
an
appropriate
respirator.
The
appropriate
respirator
would
be
need
to
provide
a
protection
factor
of
150X
which
is
beyond
the
typical
respirator
normally
specified
on
labels.
Additional
fogger
exposure
data
are
needed
to
refine
this
estimate.

Forestry
Uses
Occupation
exposure
and
risk
from
forestry
uses
of
piperonyl
butoxide
were
assessed
using
the
maximum
master
label
application
rate
of
1.25
lb
ai
per
acre
and
an
upper
range
default
assumption
of
1200
acres
treated
per
day.
The
estimated
MOE
for
mixing
loading
activities
is
less
than
the
target
MOE
of
300
when
baseline
PPE
is
assumed.
When
use
of
a
PF5
respirator
is
assumed
the
estimated
MOE
is
greater
than
the
target
MOE,
i.
e.,
risk
are
not
of
concern.
The
estimated
MOE
for
aerial
application
is
above
the
target
MOE.

Piperonyl
Butoxide
­
Occupational
Exposure
and
Risk
from
Forestry
Use
Exposure
Scenario
Maximum
Application
Rate
Amount
Treated
Estimated
MOE
Target
MOE
Mixing/
Loading
Liquid
for
Aerial
Application
Baseline
PPE
1.25
lb
ai/
acre
(
Master
Label
Rate)
1200
acres/
day
upper
range
for
forestry
(
non­
ULV
app)
60
300
PPE
=
PF5
Resp
1.25
lb
ai/
acre
1200
acres/
day
770
300
Aerial
Application
Closed
Cab
1.25
lb
ai/
acre
1200
acres/
day
2200
300
Characterization
of
Potential
Long­
Term
Exposures/
Risk
to
Pesticide
Control
Operators
Piperonyl
butoxide
is
used
to
control
a
large
number
and
a
wide
variety
of
pests
and
labels
do
not
restrict
or
preclude
repeated
applications
or
long
term
use.
Given
the
potential
for
multiple
applications
and
long­
term
use
for
occupational
handlers,
inclusion
of
a
repeated
use/
long­
term
exposure
scenario
for
pest
control
operators
and
mosquito
abatement
is
considered
reasonable.
The
results
of
the
worker
exposure
assessment
indicate
that
certain
pest
control
operator
scenarios
(
i.
e.,
mixing/
loading/
applying
and/
or
aerosol
application)
result
in
MOEs
less
than
the
target
MOE
of
1000
for
long­
term
exposure.
However,
it
is
important
to
note
that
for
Page
4
of
4
pest
control
operator
and
mosquito
abatement
scenarios,
assuming
full
day,
long
term
application
for
each
application
method
is
likely
to
significantly
overestimate
total
exposure.
Based
on
data
on
usage
of
likely
piperonyl
butoxide
containing
pesticides
presented
in
the
National
Pest
Management
Association
Survey,
this
assumption
would
result
in
significant
overestimate
of
exposure
for
PCOs.
Similarly,
assuming
continuous
usage
of
piperonyl
butoxide
containing
pesticides
for
mosquito
abatement
applications
would
also
significantly
overestimate
total
exposure
based
on
personal
communication
with
mosquito
control
district
officials
regarding
current
usage
of
these
products.
