Document ID: EPA-HQ-OPP-2005-0123-0134
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2006-03-29T05:00Z

UNITED
STATES
ENVIRONMENTAL
PROTECTION
AGENCY
WASHINGTON,
D.
C.
20460
OFFICE
OF
PREVENTION,
PESTICIDES
AND
TOXIC
SUBSTANCES
MEMORANDUM
Date:
March
21,
2006
Subject:
Agency
Responses
to
Phase
3
Public
Comments
Related
to
Methyl
Bromide's
Uses
in
Enclosures,
Chambers,
and
Structural
Food
Processing/
Storage
Facilities
From:
Steven
Weiss,
Chemical
Review
Manager
Special
Review
Branch,
Special
Review
and
Reregistration
Division
To:
Methyl
Bromide
Docket
(
EPA­
HQ­
OPP­
2005­
0123)

The
Environmental
Protection
Agency
(
EPA)
is
developing
a
Reregistration
Eligibility
Decision
(
RED)
for
the
uses
of
Methyl
Bromide
through
a
6­
phase
public
participation
process
that
the
Agency
uses
to
involve
the
public
in
developing
pesticide
reregistration
and
tolerance
reassessment
decisions.
During
Phase
3
of
the
process,
the
Agency
received
52
separate
public
comment
entries
on
the
methyl
bromide
risk
assessments
and
supporting
documents
that
are
summarized
in
Table
1.
These
52
entries
were
merged
into
a
matrix
of
96.

As
part
of
the
Phase
5
revised
risk
assessment
uses
in
enclosures,
chambers,
and
structural
food
processing/
storage
facilities,
the
Agency
has
prepared
responses
related
to
comments
on
commodity
uses
and
human
toxicity
endpoints
(
see
Table
2).
Responses
from
Biological
and
Economic
Analysis
Division
(
BEAD)
are
also
attached
(
March
15,
2006
memo
from
BEAD/
B.
Chism
to
SRRD/
S.
Weiss).
Responses
to
comments
related
to
methyl
bromide's
other
uses
(
e.
g.
pre­
plant
soil
applications)
will
be
released
later
this
year
along
with
the
Phase
5
revised
risk­
assessment
for
the
soil
uses.
Table
1.
Summary
of
Phase
3
Public
Comments
1
OPP­
2005­
0123­
0052
Comments
Submitted
by
Barbara
Sachau
2
OPP­
2005­
0123­
0053
Comments
from
Various
Private
Citizens
(
Campaign
Letters).
A
Total
of
837
Letters
were
Received.
3
OPP­
2005­
0123­
0054
Comments
from
the
Al­
FLEX
Exterminators,
Inc.
4
OPP­
2005­
0123­
0056
Comments
from
the
Association
of
Floral
Importers
5
OPP­
2005­
0123­
0057
Comments
submitted
by
the
Peruvian
Asparagus
Industry
6
OPP­
2005­
0123­
0058
Comments
submitted
by
Lee
Murphy,
President/
CEO
California
Cut
Flower
Commission
7
OPP­
2005­
0123­
0076
Comments
from
the
Lassen
Canyon
Nursery,
Inc.
8
OPP­
2005­
0123­
0077
Comments
from
the
International
Paper
Company
9
OPP­
2005­
0123­
0083
Comments
from
the
Smurfit­
Stone
Rock
Creek
Nursery
10
OPP­
2005­
0123­
0084
Comments
from
the
La
Department
of
Agriculture
and
Forestry
 
Oberlin
Nursery
11
OPP­
2005­
0123­
0085
Comments
from
the
Associated
Oregon
Hazelnut
Industry
12
OPP­
2005­
0123­
0086
Comments
from
the
Association
of
Floral
Importers
of
Florida
13
OPP­
2005­
0123­
0087
Comments
from
the
Georgia
Forestry
Commission's
Flint
River
Nursery
14
OPP­
2005­
0123­
0088
Comments
from
the
Southern
Forest
Nursery
Management
Cooperative
15
OPP­
2005­
0123­
0089
Comments
from
the
Louisiana
Department
of
Agriculture
&
Forestry
16
OPP­
2005­
0123­
0090
Comments
from
the
Texas
Forest
Service
17
OPP­
2005­
0123­
0091
Comments
from
the
South
California
Forestry
Commission
18
OPP­
2005­
0123­
0092
Comment
from
the
Tennessee
Department
of
Agriculture
19
OPP­
2005­
0123­
0093
Comments
from
the
Sunrise
Growers
Inc.
20
OPP­
2005­
0123­
0094
Comments
from
the
Sunrise
Growers,
Inc.
(
repeat
of
previous
comment)
21
OPP­
2005­
0123­
0095
Comments
from
the
Peruvian
Asparagus
Importers
Association
22
OPP­
2005­
0123­
0096
Comments
from
the
FJ
Pugliese
Company
Inc.
23
OPP­
2005­
0123­
0097
Comments
submitted
by
Don
Stringfield
24
OPP­
2005­
0123­
0101
Comments
from
the
Warren
Co.
Ag.
Extension
Service
25
OPP­
2005­
0123­
0102
Comment
submitted
by
Plum
Creek
26
OPP­
2005­
0123­
0103
Comments
from
the
California
Carrot
Board
27
OPP­
2005­
0123­
0104
Comments
from
the
California
Pepper
Commission
28
OPP­
2005­
0123­
0105
Comments
from
the
Fumigation
Service
&
Supply,
Inc.
29
OPP­
2005­
0123­
0106
Comments
from
the
California
Tomato
Commission
30
OPP­
2005­
0123­
0107
Comments
from
the
California
Tomato
Growers
Association
31
OPP­
2005­
0123­
0108
Comments
from
the
California
Pistachio
Industry
32
OPP­
2005­
0123­
0109
Comments
from
the
University
of
Hawaii
33
OPP­
2005­
0123­
0110
Comments
from
the
Royal
Fumigation
Inc.
34
OPP­
2005­
0123­
0111
Comments
from
California
Minor
Crops
Council
35
OPP­
2005­
0123­
0112
Comments
from
the
Pesticide
Action
Network
(
these
comments
were
re­
submitted,
see
below)
36
OPP­
2005­
0123­
0113
Comments
from
the
Pesticide
Action
Network
(
these
comments
were
re­
submitted,
see
below)
37
OPP­
2005­
0123­
0114
Comments
from
the
Western
Industries­
North,
Inc.
38
OPP­
2005­
0123­
0115
Comments
from
the
National
Pest
Management
Association
Inc.
39
OPP­
2005­
0123­
0116
Comments
from
the
Golf
Course
Superintendents
Association
of
America
40
OPP­
2005­
0123­
0116
Comments
from
the
Golf
Course
Superintendents
Association
of
America
41
OPP­
2005­
0123­
0117
Comments
from
Fumigation
Service
&
Supply,
Inc.
42
OPP­
2005­
0123­
0118
Comments
from
Fred
Leitz,
Leitz
Farms
LLC
43
OPP­
2005­
0123­
0119
Comments
from
the
Plant
Protection
and
Quarantine
Program/
US
Department
of
AHHIS
44
OPP­
2005­
0123­
0121
Comments
submitted
by
Bayer
Corporate
and
Business
Services,
LLC
45
OPP­
2005­
0123­
0122
Comments
submitted
by
the
Natural
Resources
Defense
Council
46
OPP­
2005­
0123­
0123
Comments
on
Methyl
Bromide
from
Private
Citizen
Carol
Fisher
47
OPP­
2005­
0123­
0124
Comments
from
John
Kepner,
Beyound
Pesticides
(
re­
submitted
version
of
OPP­
2005­
0112)
48
OPP­
2005­
0123­
0125
Comment
from
Private
Citizen
RL
McKay
49
OPP­
2005­
0123­
0126
Comments
from
Chava
McKeel
of
GCSA
50
OPP­
2005­
0123­
0127
Comments
of
the
MBIP
of
the
ACC
51
OPP­
2005­
0123­
0128
Comments
from
Pesticide
Action
Network
52
OPP­
2005­
0123­
0129
Comment
submitted
by
Almond
Hullers
&
Processors
Association
Table
2.
Responses
to
Phase
3
Public
Comments
OPP­
2005­
0123
Document
ID
Public
Comment
Agency
Response
1
0056,
0076,
0077,

0083,
0084,
0085,

0086,
0087,
0088,

0089,
0090,
0091,

0092,
0093,
0102,

0110,
0111,
0118
The
Agency
makes
a
number
of
assumptions
on
the
rates
of
application,
methods
of
use
and
other
use
practices
for
methyl
bromide.
These
assumptions
do
not
reflect
typical
use
practices.
The
Agency
assessed
risk
based
on
a
range
of
application
rates
and
other
parameters
such
as
field/
chamber
size,
weather
conditions,
etc.
Data
submitted
by
stakeholders
on
typical
rates,
methods
and
other
practices
throughout
the
risk
assessment
process
has
been
reviewed
and
incorporated
into
the
revised
risk
assessment
as
appropriate.
The
Agency
has
also
worked
with
USDA­
APHIS
to
refine
the
risk
assessment.

2
0056,
0058,
0077,

0083,
0084,
0086,

0087,
0089,
0090
0091,
0092,
0093,

0102,
0110,
0111,

0118
Based
on
the
errors
in
EPA's
assumptions
about
use
practices,
we
are
concerned
that
EPA
has
neither
reviewed
nor
incorporated
any
of
the
usage
information
previously
provided
by
the
grower
community.
The
Agency's
inaccurate
assumptions
have
resulted
in
risk
assessments
that
grossly
overestimate
exposure
and
potential
risks.
Given
the
importance
of
methyl
bromide
as
a
crop
protection
tool,
EPA's
risk
determinations
must
be
accurate.
Thus,
it
is
imperative
that
the
Agency
refine
its
occupational
and
bystander
risk
assessments
to
reflect
accurate
data
on
use
patterns,
rates,
and
methods
applications.
See
response
to
comment
#
1
3
0056,
0076,
0077,

0083,
0084,
0086,

0087,
0089,
0090,

0091,
0092,
0093
We
have
found
the
60­
day
comment
period
to
be
insufficient
given
the
amount
of
information
made
public,
the
complexity
of
the
analyses
involved
and
the
voluminous
level
of
material
placed
in
the
supporting
dockets.
The
Agency
extended
the
comment
period
another
30
days,
from
September
12,
2005
to
October
12,
2005.

4
0054
On
page
45­
50
on
the
assumptions
for
commodity
fumigations:
we
disagree
with
the
application
rate
stated
here
should
be
3lb/
1000
ft.
Also
loss
rate
should
be
a
minimum
of
2­
3
lb/
1000
ft.
And
loss
during
aeration
should
be
aeration
completed
when
tacted
with
drager
tubes
less
than
5ppm.
We
are
an
exterminating
company
dealing
with
tenting
and
fumigation
of
crates
and
pallets.
See
response
to
comment
#
1
5
0077
EPA's
assumed
typical
application
rate
is
overstated.
International
Paper's
typical
rate
is
23%
less
averaging
just
over
330
pound
of
active
ingredient
per
acre
(
350
pounds/
acre
of
Mbr/
Chloropicrin
at
the
98/
2
formulation)
.
Fields
are
typically
fumigated
every
fourth
year
either
in
the
fall
or
early
spring
.
A
crop
is
grown
in
a
field
for
two
years
after
fumigation
and
then
rotated
"
out"
for
the
next
two
growing
season
See
response
to
comment
#
1
6
0083
According
to
EPA's
Preliminary
Human
Health
Risk
Assessment
on
page
5,
they
state
that
typical
usage
rates
are
around
430
1bs/
ai.
Are
actual
usage
rate
averages
around
300
1bs/
ai
.
On
page
37,
the
agency
assumes
a
field
size
of
40
acres.
We
are
averaging
around
20
to
25
acres
per
year.
Other
usage
issues
have
been
researched
by
the
Auburn
Coop
and
the
Fumigator.
See
response
to
comment
#
1
7
0084
 
the
Agency
makes
a
number
of
assumptions
on
the
rates
of
application,

methods
of
use
and
other
use
practices
for
methyl
bromide.
These
assumptions
do
not
reflect
typical
use
practices.
The
typical
size
of
fields
treated
at
the
Oberlin
Nursery
are
anywhere
from
12
to
15
acres
See
response
to
comment
#
1
8
0085
 
the
Agency
makes
a
number
of
assumptions
on
the
rates
of
application,

methods
of
use
and
other
use
practices
for
methyl
bromide
.
These
assumptions
do
See
response
to
comment
#
1
Table
2.
Responses
to
Phase
3
Public
Comments
OPP­
2005­
0123
Document
ID
Public
Comment
Agency
Response
not
all
reflect
typical
use
practices.
Hazelnut
handlers
typically
use
approximately
3
pounds
ai
methyl
bromide
per
1,000
cu
ft
.
The
assessment
has
the
rate
at
9
pounds.
If
other
assessment
data
is
also
overstated,
it
is
imperative
that
the
correct
data
be
collected
and
used
in
the
risk
assessment.
An
extension
of
the
comment
period
may
help
industries
collect
more
information
that
can
be
used
to
justify
or
to
change
the
actual
use
figures.
Or,
perhaps
the
project
should
be
put
on
hold
until
more
correct
information
is
collected
.

9
0087
 
the
Agency
makes
a
number
of
assumptions
on
the
rates
of
application,

methods
of
use
and
other
use
practices
for
methyl
bromide.
These
assumptions
do
not
reflect
typical
use
practices.
[
Here
at
Flint
River
Nursery
we
typically
fumigate
30
acres
.
Each
field
fumigated
is
10
acres
in
size.
The
rate
of
use
is
400
lbs
ai
per
acre
in
a
67/
33
or
a
98/
2
mixture
of
Methyl
Bromide
and
Chloropicorin.]
See
response
to
comment
#
1
10
0088
As
mentioned
previously,
use
surveys
conducted
by
the
Nursery
Cooperative
for
its
members
for
2000­
2005
indicate
that,
on
average,
the
pre­
plant
use
of
MBr
for
34
nurseries
was
270
lbs
MBr
ai
per
acre.
This
is
significantly
less
than
what
is
reported
in
EPA's
use
patterns
which
reports
430
lbs/
ai
of
MBr
per
acre.

Use
surveys
conducted
by
the
Nursery
Cooperative
for
its
members
for
2000­
2005
indicate
that
approximately
23
acres
were
treated
per
year
in
each
nursery.
Many
of
these
treated
areas
were
in
small
blocks,
10
acres
or
less
in
size,
scattered
throughout
the
nursery.
Requiring
multiple
buffer
areas
for
these
small
blocks
would
be
impractical
and
cost
prohibitive
.
This
is
significantly
less
than
what
is
reported
in
EPA's
use
patterns
which
assumes
a
maximum
field
size
of
40
acres.

Based
on
the
errors
in
EPA's
assumptions
about
use
for
forest­
tree
nursery
practices,
I
am
concerned
that
EPA
has
not
incorporated
any
of
the
usage
information
previously
provided
by
the
forest­
seedling
industry.
These
inaccurate
assumptions
have
resulted
in
risk
assessments
that
grossly
overestimate
exposure
and
potential
risks.
Given
the
importance
of
methyl
bromide
as
a
standard
seedling
protection
tool,
EPA's
risk
determinations
must
be
accurate.
See
response
to
comment
#
1
11
0090
 
the
Agency
makes
a
number
of
assumptions
on
the
rates
of
application,

methods
of
use
and
other
use
practices
for
methyl
bromide
.
These
assumptions
do
not
reflect
typical
use
practices.

°
We
typically
contract
to
have
between
350
and
400
pounds
of
methyl
bromide
applied
per
acre
under
plastic
tarps
that
stay
down
at
least
49
hours
prior
to
removal
and
aeration
of
soil
.

°
In
a
typical
year
we
will
contract
to
have
between
5
and
25
acres
of
methyl
bromide
fumigation
performed
on
our
nursery
property
at
the
above
described
application
rates.
See
response
to
comment
#
1
12
0091
..
the
Agency
makes
a
number
of
assumptions
on
the
rates
of
application,
methods
of
use
and
other
use
practices
for
methyl
bromide
.
These
assumptions
do
not
reflect
typical
use
practices
.

°
At
Taylor
Nursery,
we
currently
use
only
350
lbs./
acre
of
Mbr
33%.
We
inject
it
8"
into
properly
prepared
soil
and
immediately
tarp
it
with
1
mil
plastic
.
The
tarp
remains
for
72
hours
and
then
is
removed
and
disposed
of
at
our
local
approved
See
response
to
comment
#
1
Table
2.
Responses
to
Phase
3
Public
Comments
OPP­
2005­
0123
Document
ID
Public
Comment
Agency
Response
waste
disposal
center.
I
believe
this
is
less
than
reported
as
typical.
This
is
the
rate
we
have
been
suing
for
over
25
years
.

°
We
have
125
production
acres
under
irrigation
and
out
of
this
acreage,
we
will
only
fumigate
20
acres
this
year
.
This
is
broken
up
into
20
small
fields,
which
averages
between
6­
6.5
acres
each.
Our
entire
nursery
property
is
surrounded
by
large
trees,
wind
breaks
or
pine
plantations
that
act
as
buffers
for
wind,
noise,

visual
screens
and
pesticide
applications
to
surrounding
property
owners.

13
0092
Apparently,
the
Agency
assumes
that
a
typical
application
rate
for
methyl
bromide
is
430
lbs/
ai
per
acre
.
However,
this
rate
is
not
typical
for
our
nursery.
For
several
years
we
have
used
343
lbs/
ai
of
methyl
bromide
per
acre
as
our
standard
rate
.
In
addition,
the
Agency
apparently
assumes
a
maximum
field
size
of
40
acres;

however
this
size
field
is
also
not
typical
for
our
nursery.
Our
fields
range
from
2.5
to
9.0
acres
in
size,
with
an
average
size
of
5
acres
.
In
a
typical
year,
we
would
fumigate
no
more
than
3
of
these
fields.
See
response
to
comment
#
1
14
0093
Sunrise
rarely,
if
ever,
uses
the
maximum
rate
of
Methyl
Bromide
allowable
by
law.
The
typical
maximum
rate
of
application
is
325
pounds
per
acre,
not
the
430
pounds
the
EPA
has
suggested.

Sunrise
has
no
typical
field
size
.
Our
fields
range
from
3
acres
up
to
80­
100
acres
.
There
are
many
growers
in
California
whose
fields
are
well
below
the
EPA's
typical
field
of
40
acres.
See
response
to
comment
#
1
15
0094
As
more
fully
explained
below,
we
are
concerned
that
EPA's
preliminary
risk
assessments
are
based
on
assumptions
regarding
use
rates
and
application
methodologies
that
do
not
reflect
actual
use
practices.
These
errors
appear
to
have
distorted
the
Agency's
assessments.

Typical
rates
of
application
will
vary
from
1
­
1.5
lbs
per
1000
cubic
feet.

Effective
sealing
can
reduce
additional
bump­
up
and
provide
effective
treatment.
See
response
to
comment
#
1
16
0110
The
use
rate
assumed
by
EPA
for
both
commodity
and
industrial
structural
fumigation
with
methyl
bromide
is
9
lbs./
1,000
cubic
feet.
The
most
common
application
rate
that
Royal
uses
is
4
lbs./
1,000
cubic
feet.
The
application
rates
we
use
range
from
1.5
lbs.
to
3
lbs./
1,000
cubic
feet
for
most
commodities,
3
lb./
1,000
cubic
feet
for
wood
packing
material
and
5
lbs./
1,000
cubic
feet
for
most
log
fumigations.
EPA's
assumption
of
9
lbs.
is
therefore
more
than
twice
the
norm.

EPA
also
assumes
loss
rates
of
approximately
33%
during
commodity
fumigations
and
45%
during
industrial
structural
fumigations.
Royal
experiences
negligible
loss
during
fumigation.
EPA
also
assumes
that
during
aeration,
methyl
bromide
is
specifically
channeled
away
only
in
the
case
of
venting
the
gas
through
a
stack.
Royal
directs
the
path
of
the
gas
in
all
its
fumigations
by
the
use
of
powerful
evacuation
fans
to
which
are
attached
collapsible
ducts.
With
this
equipment,
the
stream
of
exhaust
from
a
fumigation
can
be
directed
hundreds
of
feet.
In
addition,
even
in
the
case
of
a
stack,
Royal
can
utilize
ventilation
systems
that
mix
air
with
the
stream
from
fumigation
to
dilute
the
stream,
thus
enabling
it
to
compensate
for
stacks
that
are
short.
Royal
controls
bystander
presence,
which
See
response
to
comment
#
1
Table
2.
Responses
to
Phase
3
Public
Comments
OPP­
2005­
0123
Document
ID
Public
Comment
Agency
Response
does
not
appear
to
be
contemplated
by
EPA.
In
Royal's
largest
fumigations,
those
of
Chilean
fruit,
all
operations
take
place
at
night
in
a
secured
port
warehouse
and
with
the
cooperation
of
port
security
to
keep
bystanders
from
being
in
the
area.

Aeration
generally
takes
place
at
midnight
or
later,
when
few
people
are
likely
to
be
in
the
area
surrounding
the
fumigation.
Other
fumigations
are
also
performed
at
night
for
precisely
the
same
control
and
safety
goals.

17
0110
Finally,
with
respect
to
worker
exposure
EPA
mentions
the
use
of
"
respirators."

Royal's
personnel
use
self­
contained
breathing
apparatus
(
SCBA)
for
any
aspect
of
a
methyl
bromide
fumigation
where
they
might
be
exposed
to
the
gas.
Since
EPA
does
not
define
what
it
includes
in
the
category
of
"
respirator"
the
distinction
should
be
drawn,
as
SCBA
greatly
decreases
the
degree
of
worker
risk.
The
risk
assessment
does
estimate
risk
for
workers
with
no
respirator,
negative
pressure
respirators
with
a
protection
factor
of
10,
and
SCBAs
with
a
protection
factor
of
10,000.

18
0114
As
has
been
pointed
out
by
various
commenters,
certain
assumptions,
which
EPA
has
made
do
not
appear
to
reflect
actual
use
practices.
Our
focus
is
primarily
on
perishable
commodity
fumigations,
which
in
the
largest
part,
are
carried
out
under
PPQ
regulations.
The
highest
application
rate
that
we
are
required
to
apply
to
perishables
is
4
lbs/
1000
cubic
feet
and
depending
on
the
temperature
of
the
commodity
that
application
rate
may
be
as
low
as
1.5
lbs/
1000
cubic
feet
(
PPQ
T101­
a­
1
or
equivalent).
EPA
assumption
puts
application
rate
for
commodity
fumigation
at
9
lbs/
1000
cubic
feet
with
a
loss
rate
during
treatment
of
3
lbs/
1000
cubic
feet
and
6
lbs/
1000
cubic
feet
during
aeration.

Question:
In
conjunction
with
the
above
how
does
EPA
determine
the
loss
rate
and
how
does
that
relate
to
the
risk
assessment?
Based
on
the
EPA
figures,
at
an
application
rate
of
4
lbs/
1000
cubic
feet
would
we
expect
a
loss
rate
of
1.33
lbs/
1000
cubic
feet
during
treatment
and
2.66
lbs/
1000
cubic
feet
during
aeration?
The
Agency
has
based
its
assumptions
for
loss
rates
on
CDPR's
1994
Suggested
Permit
Conditions
for
Methyl
Bromide
Fumigation
and
also
the
USDA­
APHIS
PPQ
treatment
handbook
as
well
as
other
sources
of
information
(
e.
g.,
MBAO.
ORG
presentations).

19
0115
We
are
concerned,
however,
that
the
Agency
has
not
included
post
harvest
stakeholders
in
the
methyl
bromide
reregistration
process
as
effectively
as
it
did
during
the
reregistration
of
aluminum
and
magnesium
phosphide.
In
fact,

documents
the
Agency
has
released
continually
use
the
term
"
soil
fumigant"
and
generally
mislead
readers
into
thinking
that
structural
or
commodity
uses
of
methyl
bromide
are
not
covered
or
impacted
by
these
assessments.
Moreover,
at
a
July
13
technical
briefing
on
the
risk
assessments
for
methyl
bromide
and
the
other
fumigants,
EPA
noted
on
sixth
slide
of
a
239­
slide
presentation,
that
commodity
and
structural
fumigation
were
not
included.
Obviously,
the
future
use
of
methyl
bromide
in
commodity
or
structural
fumigation
would
be
impacted
by
the
final
methyl
bromide
Reregistration
Eligibility
Decision
document,
and
we
want
to
make
sure
that
only
the
most
up
to
date
and
accurate
information
is
used
to
make
regulatory
decisions.
Much
of
the
focus
thus
far
has
been
on
soil
uses
since
the
majority
of
use
in
the
US
is
from
soil
uses.

However,
the
Agency
recognizes
the
importance
and
impact
of
the
other
uses
such
as
post­
harvest
commodity
fumigation.
Furthermore,
the
risk
assessment
that
is
being
released
in
April
2006
is
based
on
commodity
uses.
The
Agency
values
the
input
of
post
harvest
stakeholders
and
encourages
comments
all
aspects
of
the
documents
included
in
the
docket
20
0117
Phosphine
fumigants
have
recently
gone
through
an
extensive
RED
process
.
MB
product
labels
need
to
be
amended
and
submitted
to
the
Agency
with
cautions
to
protect
applicators,
bystanders,
and
the
community's
environment.
The
15
RMMs
that
phosphine
registrants
and
stakeholders
worked
through
should
also
apply
to
MB
:
Fumigation
Management
Plan,
Incident
Reporting,
Monitoring
Studies,

Worker
Exposure
Limits,
Training
/
Certification.
We
at
Fumigation
Service
&
The
Agency
is
considering
a
similar
process
for
methyl
bromide.
The
Agency
is
asking
all
stakeholders
to
comment
on
risk
mitigation
options
paper
for
commodity
uses
that
was
released
along
with
the
revised
risk
assessment.
Table
2.
Responses
to
Phase
3
Public
Comments
OPP­
2005­
0123
Document
ID
Public
Comment
Agency
Response
Supply,
Inc
.
were
part
of
the
Phosphine
Coalition
that
worked
through
this
RED
for
phosphine
and
believe
that
there
is
a
workable
standard
for
Methyl
Bromide
too
.
We
ask
that
you
hold
Methyl
Bromide
to
the
same
standard
as
phosphine
and
sulfuryl
fluoride
when
it
is
evaluated
.
We
believe
that
the
new
phosphine
and
sulfuryl
fluoride
labels
have
helped
us
to
better
steward
these
products
21
0118
EPA's
Human
Health
Risk
Assessment
assumes
a
typical
rate
of
4301bs/
ai
of
methyl
bromide
per
acre.
On
all
the
vegetable
crops
we
use
methyl
bromide
on
the
recommendation
is
400
lbs
of
67%
methyl
bromide
and
33%
chloropicrin
or
67/
33.
Assuming
this
percentage
of
use
we
would
use
only
268
lb/
ai
of
methyl
bromide
per
acre
.
This
is
not
a
typical
use
in
vegetable
production
either
.
We
use
plasticulture
as
the
preferred
method
of
growing.
By
doing
this
we
cut
down
on
fertilizer,
water
and
fumigant.
The
width
of
the
row
and
how
far
apart
the
rows
are
determine
the
square
footage
of
application.
We
have
two
foot
wide
rows
and
5
feet
between
row
centers.
In
other
words
2
out
of
5
feet
is
being
used
or
40%
of
the
ground
.
Using
67/
33
at
the
recommended
rate
gives
us
1081bs/
ai
of
methyl
bromide
per
acre.
This
is
typical
usage
for
fruit
and
vegetable
farms
in
the
Midwest
.
The
size
of
our
fields
is
variable.
I
have
fields
that
are
8
acres
to
40
acres
in
size
on
the
same
farm.
We
have
multiple
locations
in
the
same
county.

We
size
fields
to
meet
planting
schedules,
water
availability,
soil
and
wind
erosion,
and
proximity
to
neighbors
when
we
plan
.
See
response
to
comment
#
1
22
0119
APHIS
is
concerned
that
EPA
may
not
have
a
complete
understanding
of
how
commodity
fumigation
is
conducted
at
our
nation's
ports­
of­
entry,
and
this
may
be
affecting
some
of
the
assumptions
that
EPA
has
made
in
developing
their
risk
assessments.
The
Agency
has
been
working
closely
with
USDAAPHIS
to
better
understand
the
commodity
fumigation
process
has
incorporated
information
from
meetings,

conference
calls,
and
written
comments
into
the
revised
risk
assessment.
It
should
be
noted
that
the
Agency
risk
assessment
covers
APHIS
and
non­
APHIS
supervised
facilities.

23
0119
EPA's
assumptions
regarding
treatment
and
flux
rates
described
in
the
preliminary
risk
assessments
on
commodity
fumigation
exceed
actual
treatment
and
flux
rates
for
imported
commodities
fumigated
under
APHIS
supervision.
The
Agency
has
based
its
assumptions
for
loss
rates
on
CDPR's
1994
Suggested
Permit
Conditions
for
Methyl
Bromide
Fumigation.
The
Agency
has
attempted
to
estimate
risk
for
a
wide
range
of
conditions.
It
should
be
noted
that
the
Agency
risk
assessment
covers
APHIS
and
non­
APHIS
supervised
facilities.

24
0119
APHIS
has
analyzed
all
treatments
conducted
under
a
variety
of
treatment
schedules
and
has
determined
that,
for
imported
commodities,
the
decrease
in
methyl
bromide
concentrations
are
much
smaller
than
that
estimated
in
EPA's
Draft
Risk
Assessment
(
Figure
5).
The
observed,
minimal
decrease
in
fumigant
is
attributable
to
absorption/
adsorption
of
the
fumigant
by
commodities
and
particularly
by
wood
packing
which
absorbs
large
amounts
of
fumigant;
the
decrease
is
not
attributable
to
loss
of
gas
from
the
enclosure
to
the
outside
(
flux).
See
response
to
comment
#
23
25
0119
APHIS
does
not
believe
that
a
model
which
requires
a
flux
input
to
estimate
bystander
risks
during
the
treatment
phase
of
fumigations
is
appropriate.
Any
decrease
in
methyl
bromide
concentrations
during
the
treatment
period
is
attributable
to
absorption
by
the
commodity
or
wood
packing.
In
the
event
that
EPA
considers
this
decrease
as
treatment
flux,
APHIS
respectfully
requests
that
the
estimate
of
loss
be
significantly
reduced,
and
the
by­
stander
risk
model,

including
the
Human
Equivalent
Concentration,
be
re­
assessed
to
reflect
an
average
treatment
time
of
3
hours
rather
than
24
hours.
The
Agency
is
now
using
PERFUM
model
and
is
incorporating
a
range
of
%
loss
rates.

26
0119
APHIS
appreciates
the
difficulty
in
modeling
the
dispersal
of
methyl
bromide
but
has
difficulty
in
understanding
how
the
use
of
the
ISCST3
model,
a
smokestack
simulation
used
to
estimate
the
concentration
of
air
pollutants
emitted
over
a
24­

hour
period,
estimates
the
dispersal
of
methyl
bromide
following
commodity
fumigation.
It
is
not
clear
whether
the
chemical
methyl
bromide
disperses
from
an
aeration
vent
in
the
same
way
as
particulate
matter
emitted
from
an
incinerator's
smokestack.
Secondly,
EPA's
model
estimates
of
treatment
rates
and
treatment/
aeration
flux
are
grossly
exaggerated
compared
to
what
occurs
during
APHIS­
supervised
commodity
fumigation.
The
Agency
is
now
using
PERFUM
model
and
is
assessing
1,
4,
and
24
hr
periods.
This
allows
for
a
closer
approximation
of
actual
emissions
and
for
better
characterization
of
risks
compared
to
the
available
HECs
for
commodity
uses.

27
0119
EPA's
model
assumes
a
commodity
treatment
rate
of
9
lb
of
methyl
bromide
per
1,000
cubic
feet.
A
graph
depicting
APHIS
fumigation
rates
is
presented
in
Figure
6.
Nearly
100%
of
imported
commodities
are
treated
at
rates
less
than
9
lb/
1,000
cubic
feet;
most
imported
commodities
are
treated
at
3
or
4
lb/
1,000
cubic
feet.

Three­
quarters
of
all
APHIS­
supervised
treatments,
including
both
imports
and
exports,
are
conducted
at
4
lb/
1000
cubic
feet
or
less.
Only
21%
of
APHISsupervised
treatments
are
at
rates
of
9
lb/
1,000
cubic
feet
or
more;
although
a
small
portion
of
these
treatments
may
be
for
imported
tiles,
most
of
these
treatments
are
for
exported
logs,
which
are
not
APHIS­
regulated
commodities.
In
an
effort
to
fulfill
the
second
prong
of
the
Congressional
mandate
(
facilitate
agricultural
trade),
APHIS,
as
a
courtesy
to
other
countries,
has
agreed
to
supervise
certain
fumigations
according
to
those
countries'
requirements,
which,

for
logs,
involve
a
treatment
rate
of
15
lb
of
methyl
bromide/
1,000
cubic
feet.
This
information
along
with
other
data
provided
to
the
Agency
by
USDA­
APHIS
has
been
incorporated
into
the
assessment
as
appropriate.

28
0119
During
a
treatment
period,
there
is
minimal,
if
any
emission
(
flux)
from
a
fumigation
enclosure,
as
it
must
be
sealed
to
hold
the
gas.
Besides
having
to
bear
the
high
cost
of
loosing
fumigant,
a
fumigator
who
lost
2
or
3
lb/
1,000
cubic
feet
during
a
treatment
period,
as
assumed
by
EPA
in
the
Draft
Risk
Assessment,

stands
to
lose
APHIS
certification
to
operate
at
U.
S.
ports­
of­
entry.
See
response
to
comment
#
25.
A
wide
range
of
loss
rates
were
considered
in
order
to
evaluate
the
possible
range
of
conditions
across
the
country.

29
0119
APHIS
is
concerned
about
the
manner
in
which
the
by­
stander
risk
model
is
calculated,
since
the
Human
Equivalent
Concentration
used
to
calculate
bystander
risk,
was
developed
based
on
a
24­
hour
exposure
of
the
expelled
stream
of
methyl
bromide,
not
a
15­
30
minute
exposure.
Furthermore,
the
assumption
that
the
entire
amount
is
carried
in
a
single
direction
to
a
model
human
being
standing
at
various
distances
from
the
aeration
site
is
unrealistic
and
overconservative;

consequently,
it
greatly
overestimates
risks
to
bystanders.
See
response
to
comment
#
26
30
0119
APHIS
is
concerned
about
the
amount
released
during
aeration.
The
total
amount
of
fumigant
released
during
aeration
can
be
no
more
than
the
total
amount
introduced
into
the
enclosure.
EPA's
model
assumes
that
6
lb/
1,000
cubic
feet
is
released
during
aeration.
Since
most
import
fumigations
are
at
4
lb/
1,000
cubic
feet
or
less
(
the
amount
expected
to
be
expelled
during
aeration)
this
model
clearly
overestimates
the
release
of
fumigant.
See
response
to
comments
#
1
&
25
31
0119
APHIS
is
concerned
about
the
use
of
this
model
in
general.
EPA
had
to
use
a
variety
of
enclosure
sizes
to
estimate
by­
stander
risk,
and
use
various
assumptions
about
flux,
aeration,
and
stack
height.
In
reality
many
of
the
largest
APHISsupervised
enclosures
are
fumigated
at
no
more
than
2
or
3
lb/
1,000
cubic
feet.

These
large
enclosures,
however,
release
much
larger
quantities
of
gas
than
do
the
smaller
enclosures,
typically
used
to
fumigate
a
small
proportion
of
imported
commodities
at
the
higher
rates
of
8
or
9
lb/
1,000
cubic
feet
or
greater.
It
would
seem
to
be
more
appropriate
to
investigate
by­
stander
risk
as
a
function
of
the
quantity
of
gas
introduced
into
an
enclosure,
rather
than
as
a
function
of
enclosure
size,
treatment
rates
and
flux
rates.
See
response
to
comment
#
27
32
0119
APHIS
notes
that
no
APHIS­
supervised
enclosure
reaches
the
250,000
cubic
foot
size
as
used
in
EPA
modeling;
the
largest
enclosure
supervised
by
APHIS
is
136,000
cubic
feet.
APHIS
also
notes
that,
unlike
EPA's
model,
which
evaluates
exposure
to
non­
active
aeration
events,
all
APHIS­
supervised
enclosures
are
actively
aerated
using
fans,
which
are
required
according
to
the
label.
See
response
to
comment
#
27
33
124
We
do
not
agree
with
the
choice
of
study
and
dose
selection
for
the
assessment
of
short­
term
and
intermediate
methyl
bromide
exposure
and
human
health
risks.
We
conclude
that
an
estimated
NOAEL
of
0.5
ppm
(
0.14
mg/
kg­
day)
should
be
used
for
assessing
short­
term
and
intermediate
risk
of
methyl
bromide
exposure.
This
NOAEL
is
estimated
by
dividing
the
LOAEL
of
5
ppm
for
decreased
responsiveness
in
dogs
observed
after
34
exposure
days
(
Newton
199439)
by
a
factor
of
ten.
The
use
of
a
ten­
fold
uncertainty
factor
to
extrapolate
from
a
LOAEL
to
a
NOAEL
using
these
data
is
consistent
with
the
ten­
fold
uncertainty
factor
applied
by
US
EPA
when
extrapolating
from
a
LOAEL
to
a
NOAEL,
where
a
true
NOEL
(
no
observable
effect
level)
is
not
evident
from
available
data.
The
Agency
has
evaluated
two
subchronic
inhalation
studies
in
dogs
and
has
conducted
a
weight­
of­
evidence
evaluation
in
establishing
the
point
of
departure
for
this
risk
assessment.
While
in
MRID
43386802
unresponsiveness
and/
or
depressed
appearance
was
reported
for
2/
8
females
exposed
to
5.3
ppm
after
32
days
of
exposure,
the
Agency
has
concluded
that
these
observations
are
spurious
given
that
no
effects
were
observed
after
5
weeks
of
exposure
at
11
ppm.

Moreover,
in
a
non­
guideline
inhalation
toxicity
study
in
dogs
(
MRID
45722801)
no
effects
were
seen
at
the
5.3
ppm
exposure
concentration
after
6
weeks
of
exposure.
Thus,
the
Agency
reaffirms
its
conclusions
that
the
NOAEL
for
these
studies
should
be
established
at
5
ppm
and
that
no
additional
uncertainty
factor
(
UF)

for
lack
of
a
NOAEL
is
required.

34
124
The
selection
of
the
chronic
inhalation
toxicity
endpoint
also
presents
a
problem.

Although
it
is
understandable
that
US
EPA
desires
to
use
the
chronic
rat
study
because
the
study
design
meets
US
EPA
guidelines
for
conducting
chronic
and
carcinogenicity
inhalation
studies
in
rodents,
the
scientific
evidence
supports
the
determination
that
dogs
are
the
most
sensitive
test
species
to
methyl
bromide
exposure.
In
2003,
US
EPA50
had
recommended
using
the
Newton
(
1994)
dog
study
for
chronic
inhalation
exposure
risk
assessment.
This
would
be
an
acceptable
approach.
If
US
EPA
insists
on
using
the
basal
cell
hyperplasia
toxicity
The
Agency
has
concluded
that
use
of
the
inhalation
chronic
toxicity
study
in
rats
is
appropriate
for
the
chronic
inhalation
risk
assessment.
This
study
is
of
the
appropriate
duration
for
this
risk
assessment
and
yield
the
lowest
HEC
(
0.13
pmm)
for
this
risk
assessment.

Since
a
NOAEL
for
the
effects
of
concern
was
not
identified
in
this
study,
the
Agency
has
retained
a
3X
uncertainty
factor
(
due
to
the
limited
severity
of
the
endpoint
in
rats51
(
LOAEL
=
3
ppm)
as
the
endpoint
for
chronic
inhalation
toxicity,
then
an
additional
uncertainty
should
be
included
(
see
discussion
below).

This
use
of
the
rat
endpoint
is
consistent
with
CDPR,
52
which
used
an
estimated
NOAEL
of
0.3
ppm
in
its
2002
risk
assessment
for
inhalation
exposures
to
methyl
bromide.
There
is
also
a
discrepancy
between
CDPR
and
US
EPA
in
the
selection
of
the
study,
critical
endpoint,
and
dose
for
chronic
dietary
risk
assessment.
In
its
2002
risk
characterization
document
for
dietary
methyl
bromide
exposure,
53
CDPR
selected
the
1996
chronic
oral
dog
study
conducted
by
Newton,
and
a
NOAEL
of
1.5
ppm
for
decreased
hemoglobin
and/
or
hematocrit
levels
in
male
dogs.
US
EPA's
decision
to
use
a
NOAEL
of
50
ppm
from
a
rat
study
is:
a)

inconsistent
with
the
widely
accepted
methodology
to
select
a
toxicity
endpoint
from
the
more
sensitive
species
when
there
are
adequate
toxicity
data
available
in
more
than
one
species,
b)
does
not
result
in
the
lowest
human
equivalent
concentration,
and
c)
is
inconsistent
with
CDPR,
something
that
US
EPA
stated
it
was
trying
to
avoid.
We
recommend
that
the
more
health­
protective
toxicity
endpoint
and
dose
level
of
concern
(
1.5
ppm)
from
the
dog
study
be
used
in
the
dietary
exposure
risk
assessment.
effect,
HED
concluded
a
3X
UF
would
be
sufficient
to
extrapolate
from
the
LOAEL
to
the
NOAEL).
As
it
pertains
to
the
Agency's
selection
of
a
point
of
departure
for
the
chronic
dietary,
the
Agency
notes
that
given
the
conduct
of
the
study
(
using
fumigated
feed)
it
is
not
feasible
to
accurately
determine
the
concentration
level
at
which
the
animals
were
exposed.

Given
the
limitations
of
this
study,
the
Agency
has
concluded
that
it
is
not
appropriate
for
selection
of
a
point
of
departure
for
risk
assessment.
Consequently,

the
Agency
has
selected
the
chronic
dietary
toxicity
study
in
rats
to
establish
a
chronic
reference
dose
(
cRfD).
In
this
study,
rats
were
exposed
to
microencapsulated
methyl
bromide
thus
allowing
for
a
more
appropriate
quantification
of
the
exposure
concentration.
The
Agency
also
notes
that
HECs
are
not
calculated
for
dietary
exposures
as
the
commenter
implies
in
part
(
b)
of
its
comments.
In
conclusion,
the
Agency
considers
the
use
of
the
Chronic
Dietary
Toxicity
Study
in
Rats
in
the
risk
assessment
is
appropriate
and
justified.

35
124
We
find
it
particularly
troubling
that
after
almost
20
years
of
intensive
evaluation
of
the
health
effects
and
risks
of
methyl
bromide
exposures,
there
is
still
a
data
gap
for
a
developmental
neurotoxicity
study,
a
key
study
for
evaluating
effects
on
what
is
probably
the
most
vulnerable
subpopulation
for
methyl
bromide
toxicity.

We
understand
that
the
Registrant
has
finally
initiated
the
study,
however
it
may
take
months
to
years
for
US
EPA
to
evaluate
the
findings,
validate
the
results,
and
decide
how
the
data
should
be
used.
When
the
study
results
are
available,
we
urge
US
EPA
to
release
them
to
the
public
to
allow
for
further
discussion
and
analysis
of
methyl
bromide
toxicity
and
risk.
Furthermore,
we
request
that
any
changes
made
to
the
risk
assessment
for
methyl
bromide
based
on
the
results
of
this
study
be
disseminated
for
public
review
and
comment.
An
inhalation
DNT
study
has
been
submitted
to
the
Agency.
The
Agency
has
reviewed
the
study
and
incorporated
into
the
revised
risk
assessment.
A
review
of
the
study
is
available
to
the
public
by
contacting
the
Chemical
Review
Manager
for
Methyl
Bromide
(
Steven
Weiss,
703­
308­
8293
or
weiss.
steven@
epa.
gov).
The
selected
endpoints
from
the
previous
risk
assessment
have
not
changed
based
on
DNT
results.
The
10x
factor
that
was
previously
applied
for
lack
of
a
DNT
has
been
removed
in
the
current
assessment.

36
124
According
to
both
US
EPA
and
CDPR,
methyl
bromide
is
highly
toxic
by
both
the
dermal
and
ocular
routes
of
exposure
(
Toxicity
Category
I).
However,
based
on
a
flawed
assumption
that
one
or
both
of
these
exposure
routes
would
not
be
expected
for
humans,
a
risk
assessment
for
dermal/
ocular
exposure
was
not
included
in
the
assessment.
There
are
enough
occurrences
of
spills
and
whole
body
exposures
described
in
the
methyl
bromide
toxicity
incident
reports
to
warrant
a
risk
determination
via
dermal/
ocular
exposure.
In
fact,
on
August
29,

2005,
a
Modesto
Bee
newspaper
article
described
a
worker
who
was
sprayed
in
the
face
and
eyes
with
methyl
bromide,
the
result
of
faulty
equipment.
We
urge
US
EPA
to
include
this
analysis
in
the
risk
assessment,
especially
for
workers.

Furthermore,
an
aggregate
exposure/
risk
assessment
must
include
dermal
exposures
along
with
all
other
routes
of
exposure.
The
Agency
agrees
that
workers
may
be
exposed
via
the
dermal
and
inhalation
route.
Risk
mitigation
measures
(
including
PPE)
focus
on
all
routes
of
exposure.
Bystander
exposure
is
limited
to
the
inhalation
route.
However,
inhalation
is
the
main
route
of
exposure
in
terms
of
the
Agency's
risk
assessment
focus.
The
Agency
believes
that
dermal
exposure
worker
studies
and
toxicity
studies
are
not
feasible
or
practical.
Incident
reports
such
as
the
one
described
in
August
29,
2005
have
been
incorporated
to
the
Agency's
risk
assessment.
37
124
In
general,
the
discussion
and
justification
for
the
use
of
uncertainty
factors
in
the
methyl
bromide
risk
assessment
is
difficult
to
follow
and
the
rationale
for
selecting
uncertainty
factors
so
unclear
as
to
appear
as
if
US
EPA's
decisions
were
subjective
and
arbitrary.
We
recommend
that
US
EPA
adopt
the
more
widely
used
and
recognized
methodology
in
risk
assessment
for
deriving
levels
of
concern
for
humans
from
toxicity
data.
That
is,
dividing
NOAELs
by
factors
of
ten
(
or
factors
of
three
only
when
adequate
data
and
scientific
support
are
available
and
a
complete
discussion
provided)
to
correct
for
interspecies
and
intraspecies
variation,
converting
LOAELs
to
NOAELs,
and
for
addressing
adequacy
or
uncertainty
in
the
database.
In
the
methyl
bromide
risk
assessment,
the
Agency
has
used
the
RfC
Methodology
developed
by
the
USEPA
Office
of
Research
and
Development
(
ORD)
and
published
in
1994.
The
RfC
methodology
applies
a
dosimetric
adjustment
that
takes
into
consideration
not
only
the
differences
in
ventilation
rate
(
MV)
but
also
the
physicochemical
properties
of
the
inhaled
compound,
the
type
of
toxicity
observed
(
e.
g.
systemic
vs.
port
of
entry)
and
the
pharmacokinetic
(
PK)
but
not
pharmacodynamic
(
PD)
differences
between
animals
and
humans.
As
a
result,
the
interspecies
UF
is
reduced
from
10X
to
3X
(
a
3X
is
retained
to
account
for
the
pharmacodynamic
differences
between
animals
and
humans).
For
a
more
detailed
discussion
of
the
use
of
the
RfC
methodology
and
uncertainty
factors
the
reader
is
referred
to
the
website
http://
cfpub.
epa.
gov/
ncea/
cfm/
recordisplay.
cfm?
deid=
7
1993
38
124
In
2001,
US
EPA
concluded
that
an
additional
uncertainty
factor
of
ten
should
be
"
retained"
for
methyl
bromide
54
as
required
by
the
Food
Quality
Protection
Act
of
1996
to
address
weight­
of
evidence
considerations
and
the
differential
toxicity
between
infants
and
children
and
adults.
In
2003,
US
EPA
reversed
its
decision
and
concluded
that
no
additional
uncertainty
factor
was
warranted
because
the
database
is
complete.
At
that
time,
the
only
new
data
to
be
submitted
to
US
EPA
was
the
Schaefer
(
2002)
dog
study
previously
addressed
in
these
comments.
In
other
words,
there
were
no
additional
or
new
data
available
to
US
EPA
specifically
addressing
developmental
neurotoxicity
or
the
differential
effects
of
methyl
bromide
on
the
developing
fetus,
infants,
and
children.
This
apparently
arbitrary
decision
was
not
discussed
in
the
2005
risk
assessment.
Nevertheless,
if
this
change
remains
in
the
risk
assessment,
the
result
is
that
the
developing
fetus,

infants,
and
children
will
not
be
afforded
additional
protection
compared
to
adults
when
exposed
to
regulatory
levels
considered
acceptable
to
US
EPA.
There
are
several
scientific
and
public
health
policy
arguments
to
justify
additional
protection
for
children
and
infants,
as
presented
below.
From
a
regulatory
perspective,
there
is
a
data
gap
for
a
developmental
neurotoxicity
data.
This
is
a
key
missing
study
because
the
available
data
from
generic
developmental
toxicity
studies
do
not
specifically
address
the
most
sensitive
endpoint
of
concern
for
methyl
bromide,
which
is
neurotoxicity.
The
observed
developmental
toxicity,

neurotoxicity,
and
genotoxicity
of
methyl
bromide
in
experimental
studies
are
other
factors,
as
is
the
observed
difference
in
sensitivity
for
the
developing
fetus
and
newborn
with
methyl
bromide
exposure,
when
compared
to
adults.

Furthermore,
there
is
a
wide
variation
in
responses
to
methyl
bromide
toxicity
observed
in
exposed
adults.
Therefore,
the
conventional
ten­
fold
uncertainty
factor
applied
for
human
variability
might
only
account
for
adult
variation,
and
The
Agency
notes
that
a
10X
UF
for
lack
of
the
DNT
was
retained
in
the
2005
risk
assessment.
Since
then,

an
acceptable
DNT
has
been
submitted
and
reviewed
by
the
Agency.
The
results
of
this
study
have
been
considered
in
the
revised
risk
assessment.
Based
on
the
availability
of
this
study
and
the
Agency's
review,

the
10X
UF
has
been
reduced
to
1X.
not
for
differences
between
adults
and
infants
and
children.
Some,
but
not
all,
of
the
observed
differences
in
sensitivity
among
fetuses,
newborn
infants,
developing
young,
and
adults
are
overlapping.
Nevertheless,
we
conclude
that
the
scientific
evidence
supports
that
an
additional
uncertainty
factor
of
ten
be
used
in
calculating
the
target
concentrations
in
air,
water,
and
the
diet
for
methyl
bromide
that
are
fully
protective
of
infants
and
children.
Therefore,
we
recommend
that
US
EPA
apply
the
default
1,000­
fold
uncertainty
factor
to
the
rat
study
LOAEL
in
order
to
define
the
chronic,
non­
carcinogenicity
level
of
concern
for
the
risk
assessment.

39
124
The
preliminary
risk
assessment
for
chronic
inhalation
risks
defines
the
level
of
concern
as
the
LOAEL
from
a
chronic
toxicity/
carcinogenicity
in
rats
divided
by
an
uncertainty
factor
of
100.
The
universal
risk
assessment
default
is
to
apply
a
1,000­
fold
uncertainty
factor
when
no
NOAEL
is
identified
from
a
toxicity
study
in
animals.
However,
in
its
risk
assessment
US
EPA
assumes:
a)
their
RfC
methodology
already
accounts
for
a
three­
fold
interspecies
difference,
and
b)
the
toxicity
endpoint,
basal
cell
hyperplasia,
is
not
severe
enough
effect
to
warrant
the
full
default
uncertainty
factor
value
of
ten­
fold
for
the
extrapolation
of
a
NOAEL
from
a
LOAEL.
This
logic
is
flawed
on
three
grounds.
First,
as
mentioned
above,

rats
are
less
sensitive
to
methyl
bromide
toxicity
than
dogs.
This
could
mean
that
the
interspecies
differences
between
humans
and
experimental
animals
are
underestimated.
One
solution
is
to
use
the
intermediate
term
toxicity
study
results
of
Newton
(
1994)
for
chronic
toxicity
as
proposed
by
US
EPA
in
2003.
However,

the
studies
in
dogs
were
not
designed
to
be
chronic
toxicity/
carcinogenicity
studies.
A
more
practical
solution
is
to
use
a
larger
uncertainty
factor
in
deriving
the
levels
of
concern.
See
response
to
comment
#
34
40
124
Methyl
bromide
is
a
direct­
acting
mutagen,
especially
in
in
vitro
systems.
It
was
found
positive
in
Salmonella
typhimurium
strains
TA
100
and
TA
1535,

Escherichia
coli
strains
Sd­
4
and
WP2hcr,
and
in
Saccharomyces
cerevisiae.
It
also
produced
a
dose­
dependent
induction
of
sex­
linked
recessive
lethality
in
Drosophila
melanogaster.
In
in
vivo
assays,
methyl
bromide
was
found
to
cause
dominant
lethal
mutations,
an
increase
of
micronuclei,
and
a
dose­
related
increase
in
the
frequency
of
sister
chromatid
exchanges
in
bone
marrow.
DNA
adducts
were
detected
in
liver,
lung,
stomach,
and
forestomach
of
rats
exposed
to
high
concentration
of
methyl
bromide
by
inhalation.
Although
there
is
no
clear
evidence
of
oncogenicity
in
the
currently
available
chronic/
carcinogenicity
studies
in
animals,
CDPR
in
its
Summary
of
Toxicological
Data
for
Methyl
Bromide,

does
describe
some
data
that
are
suggestive
of
carcinogenic
potential.
This
is
a
significant
biological
contradiction.
The
lack
of
correlation
between
the
strong
mutagenic
activity
and
the
largely
negative
results
in
cancer
bioassays
for
methyl
bromide
is
significant
enough
to
warrant
discussion
in
the
risk
assessment
as
well
as
some
added
degree
of
uncertainty
in
the
results.
Finally,
there
is
recent
evidence
that
methyl
bromide
increases
the
incidence
of
prostate
cancer
in
male
agricultural
workers
(
applicators).
62
The
Agency's
classification
of
methyl
bromide
as
"
not
likely
to
be
carcinogenic
in
humans"
fails
to
encompass
a
growing
body
of
epidemiology.
A
recent
large
prospective
cohort
study
conducted
by
the
National
Cancer
Institute
of
55,332
male
pesticide
handlers
in
two
states
The
Agency
acknowledges
the
positive
findings
in
the
genotoxicity
testing
battery.
However,
no
indication
of
carcinogenesis
is
evident
in
the
rat
or
mouse
cancer
bioassays.
The
Agency
also
recognizes
the
findings
from
the
Agricultural
Health
Study
(
AHS)
suggesting
a
link
between
prostate
cancer
and
MeBr
use.
In
2003,

methyl
bromide
was
among
a
small
numbers
of
pesticides
linked
with
an
overall
14%
excess
of
prostate
cancer.
The
study
was
of
566
new
cases
of
prostate
cancers
between
1993
and
1999,
among
55,332
farmers
and
commercial
pesticide
applicators.

Cumulative
exposure
increased
risk
to
3
fold
for
methyl
bromide.
Lead
by
the
National
Cancer
Institute
(
NCI)
and
other
Federal
Agencies,
including
US
EPA,

this
study
is
being
followed
by
a
second
study
that
is
designed
to
confirm
the
previous
findings,
since
a
family
history
of
prostate
cancer
increased
risk.

The
second
study
is
of
men
diagnosed
with
prostate
cancer
since
the
completion
of
the
first
study.
The
second
study
when
completed
will
be
published,
and
so
(
Iowa
and
North
Carolina)
found
use
of
methyl
bromide
significantly
associated
with
heightened
risk
of
prostate
cancer.
The
association
had
an
exposure
related
trend
with
odds
ratios
of
2.73
(
95%
CI
1.18,
6.33)
and
3.47
(
95%
CI:
1.37,
8.76)

in
the
two
highest
exposure
categories.
63
Moreover,
a
study
of
California
farmworkers
(
ecological
epidemiology
study
design)
found
a
suggestion
of
elevated
risk
of
prostate
cancer
among
farmworkers
judged
to
have
high
exposures
to
methyl
bromide
as
assessed
from
pesticide
use
records
for
crops,

counties
and
time
periods
of
work.
The
Odds
Ratio
was
1.16
(
95%
CI:
0.77,

1.75).
64
Virtually
no
discussion
of
this
study
is
included
in
the
2005
risk
assessment
or
any
of
the
post
2003
memoranda
and
documents
produced
by
US
EPA
staff.
This
is
an
important
oversight
that
must
be
corrected.

The
new
human
evidence
linking
methyl
bromide
exposures
with
increased
risk
of
cancer
coupled
with
the
strong
evidence
of
genotoxic
and
mutagenic
potential
of
methyl
bromide
supports
our
determination
that
EPA
needs
to
conduct
a
thorough
and
transparent
scientific
reassessment
of
the
cancer
risk
associated
with
methyl
bromide.
This
assessment
should
undergo
public
review
by
a
Scientific
Advisory
Panel
that
includes
authors
of
the
main
epidemiology
and
ecological
studies
of
methyl
bromide
cancer
risks.
Presuming
that
a
risk
of
cancer
is
found
to
be
associated
with
methyl
bromide,
EPA
should
conduct
a
quantitative
risk
estimate
(
Q*)
presuming
linearity
at
low
exposures.
The
EPA
2005
Cancer
Guidelines
Supplemental65
are
clear
that
when
infants
or
children
may
be
exposed,
the
default
assumption
is
to
assume
no
safe
level
of
exposure,
and
use
a
linear
low
dose
extrapolation
for
mutagens.
The
EPA
assessment
of
methyl
bromide
cancer
risks
will
have
no
credibility
or
scientific
defense
if
EPA
fails
to
conduct
a
thorough
and
transparent
review
of
the
cancer
risks
for
methyl
bromide
consistent
with
the
2005
Cancer
Guidelines.
far
it
reportedly
has
found
no
excess
risk
associated
with
methyl
bromide
exposure.
At
this
time,
there
is
no
definitive
explanation
for
the
differences
in
these
two
studies
and
further
investigations
are
being
conducted.
When
the
results
of
these
evaluations
become
available,
the
Agency
will
reevaluate
the
carcinogenic
classification
for
methyl
bromide.

41
124
Chloropicrin
is
combined
with
methyl
bromide
as
a
warning
agent
and
also
as
an
active
ingredient.
Chloropicrin
is
used
with
methyl
bromide
in
various
products
at
ratios
varying
from
approximately
1:
400
to
1:
1.
In
California,
4.93
million
pounds
of
chloropicrin
were
reported
used
in
1997,
compared
to
7.38
million
pounds
of
methyl
bromide
(
Pesticide
Use
Report,
CDPR,
2003).
This
is
particularly
relevant
in
applications
to
strawberries,
for
which
reported
methyl
bromide
use
in
2003
was
3.67
million
pounds,
and
reported
chloropicrin
use
was
3.28
million
pounds
presumably
applied
together).
US
EPA
includes
a
brief
discussion
of
the
public
health
data
regarding
chloropicrin/
methyl
bromide
formulations
in
its
risk
assessment.
However,
there
is
not
enough
information
to
adequately
convey
the
impact
of
combining
these
two
active
ingredients
on
human
health.
We
have
provided
general
comments
regarding
US
EPA's
methods
to
evaluate
cumulative
risks
of
the
soil
fumigants
(
see
Section
1.5).
It
is
essential
that
US
EPA
quantify
the
health
risks
of
the
exposure
to
the
combination
of
methyl
bromide
and
chloropicrin,
including
a
complete
toxicological
evaluation
of
combined
toxicity,

exposure,
and
interaction
between
chloropicrin
and
methyl
bromide
to
address
the
risk
of
using
these
formulations.
When
US
EPA
completes
its
assessment
for
chloropicrin
as
an
active
ingredient,
we
believe
that
the
findings
will
demonstrate
that
chloropicrin
is
much
more
acutely
toxic
than
methyl
bromide
(
up
to
about
50
times
more
potent
as
an
irritant).
Therefore,
we
believe
that
the
effects
of
Soil
Uses
­
Phase
5
of
The
Agency's
risk
assessment
for
methyl
bromide's
soil
uses
along
with
the
Phase
3
risk
assessment
for
chloropicrin
is
planned
to
begin
this
summer.
Since
the
focus
of
this
comment
is
on
soil
uses,
a
response
will
be
included
with
the
release
of
Phase
5
risk
assessment
for
methyl
bromide's
soil
uses.
chloropicrin,
and
not
methyl
bromide
will
dominate
the
acute
toxicity
hazard
from
the
use
of
chloropicrin/
methyl
bromide
mixtures.
In
addition,
because
the
volatility
and
evaporation
rate
of
chloropicrin
is
lower
than
that
of
methyl
bromide,
it
is
likely
that
chloropicrin
persists
longer
in
the
environment.

Therefore,
measured
levels
of
methyl
bromide
in
ambient
air
would
not
accurately
predict
chloropicrin
levels
based
on
the
initial
mixture
ratio.
It
appears
that
the
longer­
duration
inhalation
exposures
from
use
of
the
combined
products
could
be
essentially
chloropicrin
exposure.
We
have
already
alluded
to
the
polymorphism
of
glutathione­
S­
transferase
(
GST)
enzymes
in
humans
and
the
role
of
GST
in
mediating
methyl
bromide
toxicity.
Because
GST
also
activates
chloropicrin66
there
is
clearly
a
need
for
US
EPA
to
research
the
association
between
the
mechanism
of
action
and
the
cumulative
toxicity
of
these
two
agents.
In
looking
toward
the
future
for
assuring
worker
and
public
health
and
safety
related
to
fumigants,
we
remain
concerned
about
the
absence
of
regulatory
controls
specific
to
chloropicrin,
an
agent
with
high
acute
toxicity,
and
chloropicrin
used
in
combination
with
methyl
bromide
and
other
fumigants.
Some
registered
methyl
bromide
products
currently
contain
up
to
50%
chloropicrin,
thereby
increasing
our
concern
regarding
this
agent.
Even
if
methyl
bromide
use
continues,
or
if
its
use
declines
or
is
phased
out
altogether,
it
is
likely
that
some
growers
will
choose
to
use
other
fumigant
that
also
utilize
chloropicrin
as
an
active
ingredient
and
warning
agent.
Since
products
containing
chloropicrin
are
being
re­
evaluated
for
registration
purposes
at
this
time,
it
seems
appropriate
and
timely
that
US
EPA
initiate
rule
making
for
chloropicrin,
as
it
is
used
in
combination
with
other
soil
fumigants,
in
particular
methyl
bromide
and
Telone.
We
believe
that
when
assessed
together,
the
combination
of
the
toxicity
levels
of
concern
and
the
exposure
risks
for
residents
and
workers
will
require
even
more
stringent
mitigation
and
control
measures
than
the
use
of
either
of
these
chemicals
alone.
It
is
quite
possible
that
the
data
will
demonstrate
that
there
is
no
acceptable
means
to
handle
mixtures
of
methyl
bromide
and
chloropicrin.

42
124
For
methyl
bromide,
there
are
four
distinct
sources
of
exposure
in
the
environment
and
workplace
(
air,
water,
diet,
and
direct
contact)
and
three
important
exposure
routes
(
inhalation,
ingestion,
and
dermal
contact).
An
appropriate
aggregate
risk
assessment
for
a
single
chemical
considers
all
routes
of
exposure
together
to
characterize
short­
term
(
acute),
intermediate
(
subchronic)
and
long­
term
(
chronic)

risks.
Although
the
toxicity
endpoint
often
differs
in
animal
studies
depending
on
the
route
and
duration
of
exposure,
for
methyl
bromide
there
are
common
endpoints
for
which
aggregate
risks
can
be
estimated.
At
a
minimum,
these
toxicity
endpoints
include
neurotoxicity,
weight
loss,
and
developmental
effects.

The
sections
referring
to
aggregate
risk
assessment
are
so
poorly
written
that
is
not
clear
what
approach
US
EPA
has
taken
in
deriving
aggregate
risks
for
methyl
bromide.
The
document
does
not
present
a
useful
characterization
of
risks
from
exposure
through
multiple
exposure
routes.
Therefore,
the
risk
assessment
is
incomplete
in
this
regard.
Most
likely,
inhalation
risks
would
dominate
an
aggregate
risk
assessment,
especially
for
subchronic
and
chronic
toxicity.

However,
dermal
exposure
is
especially
critical
for
acute
exposures
in
workers,

but
was
completely
ignored
by
US
EPA.
We
recommend
the
authors
revise
the
The
Agency
believes
that
its
aggregate
assessment
is
appropriate.
It
is
the
Agency's
policy
not
to
aggregate
worker
exposure
with
dietary
exposure.

Nonoccupational
exposure
to
methyl
bromide
via
the
dermal
route
is
not
expected.
In
terms
of
the
acute,
sub
chronic,
and
chronic
aggregate
risk,
the
Agency's
estimates
that
the
contribution
of
dietary
and
drinking
water
exposure
is
negligible
(<
14%)
in
comparison
to
exposure
from
bystander
inhalation
exposure.

Additionally,
it
should
also
be
noted
that
in
the
current
assessment
neither
dietary
nor
combined
dietary
and
water
exposures
were
of
concern.
risk
assessment
document
to
include
a
full
quantitative
analysis
of
all
three
exposure
routes
and
all
four
exposure
sources
and
provide
a
table
showing
aggregate
risks
for
acute,
subchronic
and
chronic
exposure
to
methyl
bromide.

43
0122
Would
OPP
consider
in
all
its
risk
assessments
placing
the
Data
Evaluation
Reports
(
DER)
into
the
Docket
for
the
studies
that
EPA
relies
on
as
the
basis
for
derivation
of
the
reference
dose
and
toxicological
assessment?
Without
access
to
the
underlying
data
it
is
impossible
for
the
public
to
do
much
more
than
rely
on
the
OPP
risk
assessment
document.
It
is
a
logical
impossibility
to
evaluate
the
reliability
of
the
risk
assessment
by
relying
only
on
the
information
provided
in
the
risk
assessment
itself.
Even
public
access
to
the
EPA
DER's
would
be
very
helpful,
since
this
provides
some
additional
detail
about
the
study
design
and
findings,
along
with
the
expert
opinion
of
EPA
technical
staff.
For
copies
of
DERs
not
included
in
the
docket,
contact
the
Chemical
Review
Manager
for
Methyl
Bromide
(
Steven
Weiss,
703­
308­
8293
or
weiss.
steven@
epa.
gov).

44
0122
How
will
EPA
consider
the
toxicity
data
suggesting
that
different
species
have
varying
sensitivities
to
methyl
bromide,
and
therefore
that
humans
are
likely
to
also
have
varying
sensitivities?
For
example,
in
the
developmental
toxicity
study
(
MRID
41580401),
pregnant
rabbits
(
26
animals/
dose)
were
exposed
by
whole
body
inhalation.
In
the
high
dose
treatment
group
(
80
ppm)
3/
26
adult
exposed
rabbits
were
reported
by
EPA
to
exhibit
signs
of
toxicity
(
lethargy,
ataxia,
etc.),

and
exhibited
a
treatment­
related
but
not
dose­
related
decrease
in
body
weight.

This
suggests
that
there
may
be
individual
differences
in
response
to
MeBr
toxicity,
likely
mediated
through
differences
in
glutathione
activity.
Thus,
even
a
full
10X
adjustment
for
variation
within
species
is
likely
inadequate.
Has
EPA
fully
considered
the
implications
of
glutathione
differences
across
individuals?
The
Agency
has
considered
the
variation
that
is
likely
to
occur
within
a
species
and
has
therefore
retained
a
10X
UF
for
the
intraspecies
variation
in
keeping
with
the
Agency's
policy
and
standard
practices.

45
0122
Acute
dietary
(
all
exposure
scenarios)
and
acute
inhalation:
How
does
EPA
justify
eliminating
the
10X
FQPA
based
on
the
expected
receipt
of
the
required
inhalation
DNT
study,
without
having
received
and
reviewed
the
study,
and
given
data
in
two
species
indicating
juveniles
are
more
sensitive
than
adults?
The
10X
FQPA
is
meant
to
adjust
for
increased
sensitivity
of
the
juvenile,
compared
with
the
adult,
and
not
to
simply
check
off
whether
or
not
data
has
been
received.
How
is
EPA
intending
to
evaluate
and
incorporate
the
findings
of
the
DNT?
What
will
EPA
do
if
the
results
indicate
that
juveniles
are
likely
to
be
more
than
10X
sensitive
than
adults
to
MeBr
toxicity?
Does
EPA
intend
to
simply
waive
the
10X
FQPA
factor
if
a
test
is
received,
no
matter
what
the
data
indicate?
See
response
to
comment
#
38
46
0122
Acute
dietary
(
all
exposure
scenarios)
and
acute
inhalation:
How
does
EPA
justify
reducing
the
FQPA
factor
from
10X
to
1X,
given
the
rabbit
developmental
toxicity
data
in
rabbits
(
MRID41580401)
used
by
EPA
reports
much
more
severe
and
irreversible
effects
in
the
offspring,
compared
with
the
exposed
mothers?
This
study
reports
that
at
the
high
dose
(
80
ppm;
28mg/
kg/
day)
mothers
experienced
toxicity
including
ataxia,
lethargy,
decreased
apetite,
etc.,
whereas
in
the
exposed
offspring
toxicity
effects
included
fused
vertebrae,
failure
to
develop
a
gall
bladder,
and
decreased
body
weight.
The
number
of
fused
sternebrae
in
fetallyexposed
offspring
was
statistically
significantly
increased
in
the
high
dose
group
(
12.6%)
compared
to
the
control
group
(
0%).
These
data
demonstrate
that
the
effects
in
the
offspring,
fused
vertebrae
and
failure
to
develop
a
gall
bladder,
are
considerably
more
severe
than
the
observations
in
the
mother
animals
(
lethargy
ataxia)
at
the
same
dose.
Yet,
the
EPA
has
determined
that
both
the
mothers
and
In
the
developmental
toxicity
study
in
rabbits
both
maternal
and
developmental
NOAELs
were
established
at
40
ppm.
The
Agency
concludes
from
this
data
that
no
quantitative
sensitivity
differences
exist
between
adult
and
young
animals
and
that
use
of
a
40
ppm
NOAEL
as
a
point
of
departure
would
be
protective
of
the
effects
noted
in
both
maternal
animals
and
the
developing
fetus.
As
a
result,
no
additional
uncertainty
factor
is
required
for
this
risk
assessment.
the
offspring
show
the
same
NOAEL
(
40
ppm)
and
the
same
LOAEL
(
80
ppm).

In
contrast,
the
FQPA
Safety
Factor
Committee
(
June
21,
2001;
0035)

recommended
retaining
a
full
10X
FQPA
factor
based
on
both
the
qualitative
and
quantitative
effects
in
the
rabbit
study
and
also
"
qualitative
and
quantitative
evidence
of
increased
susceptibility
following
pre­
and
postnatal
exposure
to
methyl
bromide
in
the
2­
generation
reproduction
study
in
rats"
(
June
21,
2001;

0035).
A
factor
of
10X
is
supported
by
the
reproduction
rat
study
(
MRID
00160477),
for
which
EPA
reports
a
parental
NOAEL
of
30
ppm,
and
an
offspring
NOAEL
of
3
ppm.

47
0122
Short­
and
Intermediate­
term
inhalation
(
occ
and
non­
occ):
Why
has
EPA
not
considered
and
discussed
the
dog
study
by
Newton
(
1994),
which
has
a
lower
and
therefore
more
protective
LOAEL
of
5
ppm,
than
the
dog
study
used
by
EPA
with
a
NOAEL
of
5
ppm?
Since
there
are
two
available
non­
guideline
methyl
bromide
inhalation
studies
conducted
in
dogs
(
Newton,
1994;
Schaefer,
2002),
why
has
EPA
only
discussed
and
evaluated
one
for
this
assessment?
Both
studies
have
been
reviewed
by
California
EPA
and
the
National
Academies
review
in
2000.

The
Newton
study
reports
a
LOAEL
of
5
ppm
based
on
decreased
responsiveness
in
dogs
after
34­
days
of
exposure,
and
does
not
determine
a
NOAEL.
In
its
2003
review,
EPA
determined
that
the
Newton
study
was
most
appropriate
to
derive
a
toxicity
endpoint
for
subchronic
and
chronic
inhalation,
but
changed
its
determination
in
its
2005
assessment.
Given
the
importance
of
this
decision,

would
EPA
explain
why
it
selected
the
less
protective
endpoint
rather
than
the
more
protective
value?
Why
has
EPA
not
selected
the
more
protective
study,
and
then
applied
a
10X
UF
to
extrapolate
from
a
LOAEL
of
5
ppm
to
a
NOAEL
of
0.5
ppm,
because
the
study
did
not
identify
a
true
"
no
effect"
level?
How
does
EPA
explain
the
inconsistency
between
its
own
earlier
determination
and
this
more
recent
less
protective
one?
How
does
EPA
explain
its
inconsistency
between
its
more
recent
assessment
and
that
done
by
California
EPA?
See
response
to
comment
#
33
48
0122
Short­
and
Intermediate­
term
inhalation
(
occ
and
non­
occ):
How
does
EPA
justify
selecting
a
NOAEL
of
5
ppm
from
the
dog
study
(
MRID
43386802),
rather
than
the
lower
and
therefore
more
protective
NOAEL
of
3
ppm
(
LOAEL
of
30
ppm)

from
the
multi­
generation
rat
reproduction
study
(
Appendix
B)?
The
nonoccupational
HEC
value
resulting
from
the
offspring
in
the
rat
study
is
0.54
ppm,

significantly
lower
than
the
HEC
value
derived
from
the
dog
study
of
1.0
ppm.

The
occupational
HEC
value
derived
from
the
rat
study
is
2.3
ppm,
lower
than
the
4.4
ppm
value
derived
from
the
dog
study
(
Appendix
B).
How
does
EPA
justify
choosing
the
less­
protective
study
NOAEL?
Has
EPA
fully
considered
that
pregnant
women
work
in
agriculture
fields
and
may
be
involved
in
fumigation
activities,
and
in
addition
children
are
legally
allowed
to
do
agriculture
work
and
may
be
involved
in
fumigation
activities?
Does
EPA
not
think
that
a
NOAEL
derived
from
the
offspring
of
a
multigenerational
reproduction
rat
study
is
as
relevant
to
inhalation
risks
as
a
NOAEL
derived
from
an
adult
dog
study?
In
addition,
the
selection
of
the
NOAEL
from
the
dog
study
should
also
be
more
protective.
The
Agency
has
selected
the
subchronic
inhalation
dog
study
for
this
risk
assessment.
This
study
is
of
the
appropriate
duration
for
these
risk
assessments.

Though
a
lower
HEC
was
identified
for
the
offspring
toxicity
in
the
multigeneration
toxicity
study
in
rats,

this
study
was
not
used
since
the
effects
noted
occurred
after
a
longer
period
of
exposure
than
the
ones
considered
for
these
risk
assessments
49
0122
Short­
and
Intermediate­
term
inhalation
(
occupational
and
non­
occupational):

How
does
EPA
resolve
the
discrepancy
between
its
toxicity
profile
determination
The
Agency
notes
the
discrepancy
in
the
document
and
will
change
the
toxicity
profile
to
reflect
its
most
recent
for
the
dog
study
(
Appendix
A)
and
its
use
of
the
data
in
the
human
health
inhalation
risk
assessment?
EPA
reports
that
it
has
used
a
5­
7
wk
inhalation
study
in
dogs
(
MRID
43386802)
as
a
basis
for
its
HED/
HEC's.
Yet,
the
Appendix
A
toxicity
profile
reports
that
the
NOAEL=<
5ppm
and
the
LOAEL=
5
ppm
(
0.21
mg/
L)
based
on
decreased
responsiveness
in
females.
However,
in
its
final
Human
Health
Inhalation
Risk
Assessment,
EPA
has
reported
a
NOAEL=
5
ppm
and
a
LOAEL=
10
ppm,
based
on
the
same
toxicity
endpoint
of
decreased
responsiveness
in
females,
and
also
fecal
effects
and
eye
irritation
(
MRID
45722801).
If
EPA
did
not
determine
a
true
NOAEL
for
females
from
the
study,

why
has
EPA
not
used
an
UF
of
at
least
3X
and
preferable
10X,
as
is
its
normal
practice?
determination
that
the
5
ppm
is
a
NOAEL.

50
0122
Subchronic
inhalation:
How
does
EPA
justify
making
a
determination
that
findings
of
unresponsiveness
in
female
dogs
exposed
to
methyl
bromide
(
MRID
43386802)
are
not
treatment
related
"
because
these
effects
did
not
show
clear
dose­
response
relationship"
(
Appendix
A)
when
only
4
dogs
/
sex/
dose
were
used
in
the
study?
Has
EPA
calculated
the
power
of
the
study
to
find
a
dose­
response
relationship
with
so
few
animals?
Has
EPA
considered
the
clear
dose­
response
trend
in
the
5
wk
data,
where
2/
8
dogs
at
53.1
ppm
showed
decreased
activity
by
day
14,
3/
8
dogs
at
102.7
ppm
by
day
9,
and
all
dogs
by
sacrifice.
Can
EPA
justify
dismissal
of
toxicity
simply
because
a
dose­
response
isn't
evident
from
such
a
small
and
underpowered
study?
Has
EPA
considered
the
more
likely
interpretation
that
the
effect
is
treatment­
related
and
suggests
that
there
are
sensitive
individuals
within
the
same
species
that
respond
variably
to
MeBr
exposure?
See
response
to
comment
#
33
51
0122
Inhalation
endpoints:
How
does
EPA
justify
reducing
the
interspecies
UF
from
10X
to
3X,
based
on
pharmacokinetic
species
extrapolation
data
that
has
only
been
validated
in
rats,
and
not
in
the
species
used
by
EPA
for
its
assessment,

rabbits
or
dogs?
EPA
has
used
only
a
3X
interspecies
adjustment
for
acute,

subchronic
and
chronic
inhalation
determinations.
However,
this
reduction
has
only
been
validated
in
rats
and
mice.
EPA
used
dog
and
rabbit
studies
for
its
inhalation
toxicity
endpoints.
Since
there
are
no
data
to
guide
the
extrapolation
from
rodent
metabolism
to
either
dogs,
rabbits,
or
humans,
how
can
EPA
justify
reduction
in
the
protection
factor?
This
is
especially
unscientific
given
the
evidence
from
both
the
dog
and
rabbit
studies
(
see
points
2
and
7)
suggesting
that
there
is
significant
variability
within
species,
and
therefore
likely
also
between
species
and
within
humans,
in
response
to
MeBr
toxicity.
California
DPR
used
a
10X
interspecies
extrapolation
factor
in
its
assessment
of
MeBr,
and
this
was
reviewed
and
supported
by
the
National
Academies
in
its
review.
See
response
to
question
#
37.
More
specifically,
for
the
case
where
a
dog
study
is
used
the
effects
of
concern
are
systemic.
In
the
case
of
systemic
effects,

the
RGDR
is
defined
as
the
ratio
of
the
blood:
gas
partition
coefficient
of
the
chemical
for
the
test
species
to
humans
(
Hb/
g
animal/
Hb/
g
human).
When
this
ratio
is
unknown
or
when
the
Hb/
g
animal
>
Hb/
g
human
a
default
value
of
1.0
is
used
as
the
RGDR.
Thus
the
calculations
used
in
the
risk
assessment
are
consistent
with
the
recommendations
put
forth
in
the
RfC
methodology
document
available
at
the
website
cited
in
the
response
to
comment
#
37
52
0122
Why
has
EPA
failed
to
fully
consider
the
implications
of
glutathione
polymorphisms
in
humans
as
an
indication
of
diverse
intraspecies
sensitivities?

The
National
Academies
recommended
that
this
issue
be
more
fully
considered
in
its
review.
Fully
understanding
the
mechanism
of
toxicity
of
MeBr
will
involve
consideration
of
the
human
polymorphic
GST
catalysing
conjugation
following
MeBr
inhalation.
Inter­
individual
variations
in
xenobiotic
metabolism
capacities
may
be
due
to
polymorphisms
of
the
genes
coding
for
the
enzymes
themselves
or
of
the
genes
coding
for
the
receptors
or
transcription
factors
which
regulate
the
See
response
to
comment
#
44
expression
of
the
enzymes.
Also,
polymorphisms
in
several
regions
of
genes
may
cause
altered
ligand
affinity,
transactivation
activity
or
expression
levels
of
the
receptor
subsequently
influencing
the
expression
of
the
downstream
target
genes.
ii
A
medical
case
report
noted
that
genotyping
of
the
glutathione­
S­
transferase
TI
enzyme
in
erthyrocytes
characterized
a
predisposition
to
the
neurotoxic
effects
of
methyl
bromide.
iii
How
will
OPP
consider
its
evaluation
to
be
complete
if
these
intraspecies
variations
are
not
fully
considered
and
discussed,
and
the
magnitude
of
such
variations
evaluated?

53
0122
How
does
EPA
intend
to
incorporate
the
risks
related
to
continued
MeBr
use
from
skin
cancer
and
other
illnesses
resulting
from
ozone
depletion
?
Assessment
of
health
risks
under
FIFRA
must
include
the
full
range
of
such
risks,
including
methyl
bromide's
adverse
effects
on
public
health
and
the
environment
through
ozone
depletion.
See,
for
example,
ICF,
Inc,
"
Economic
Impact
Analysis
for
Methyl
Bromide
Allocation
in
the
United
States,
Chapter
4
(
Revised
Draft
Report,

Dec.
2,
2003)
and
Chapter
8
(
Revised
Draft
Report,
Oct.
9,
2003).
(
NRDC
will
submit
copies
of
these
two
documents
to
the
docket
by
hand
on
October
20,

2005.)
This
report
assessed
the
risks
of
skin
cancer
and
other
illnesses
from
an
assumed
schedule
of
critical
use
exemptions
in
the
United
States
for
a
13­
year
period
running
from
2005
through
2017
(
Chapter
4,
p.
45,
Exh.
4.1.1).
The
table
shows
that
the
total
amount
of
critical
use
exemptions
in
the
U.
S.
assumed
over
this
period
is
approximately
193
million
pounds.
(
This
figure
is
derived
as
follows:
The
annual
exemption
percentages
presented
in
Table
4.1.1.
total
343
percent
of
the
U.
S.
1991
baseline
level
of
methyl
bromide
production
and
consumption,
which
was
25,528
metric
tons.
Multiplying
by
3.43
yields
87,561
metric
tonsm
or
approximately
193
million
pounds.)
Chapter
8
of
the
report
applies
a
model
developed
by
ICF,
known
as
the
Atmospheric
and
Health
Effects
Framework
("
AHEF"),
to
produce
estimates
of
the
likely
increases
in
skin
cancer
mortality,
non­
fatal
skin
cancer
incidence,
and
cataract
incidence
resulting
from
emissions
of
ozone­
depleting
chemicals,
including
methyl
bromide.
Using
the
AHEF
model,
the
health
impacts
of
methyl
bromide
exemptions
totaling
193
million
pounds
are
estimated.
Exhibit
8.3.1
summarizes
the
results:

o
125
skin
cancer
deaths
(
83
from
cutaneous
malignant
melanoma
and
42
from
basal
and
squamous
cell
carcinoma);

o
24,221
non­
fatal
skin
cancer
cases
(
660
from
cutaneous
malignant
melanoma
and
23,
561
from
basal
and
squamous
cell
carcinoma);
and
o
8,105
cataract
cases.

(
Exhibit
8.3.1
also
presents
uncertainty
ranges
reflecting
a
variety
of
factors.
For
example,
the
range
for
skin
cancer
deaths
extends
from
9,689
to
38,753.
The
range
for
cataract
cases
extends
from
3,242
to
12,968.)

How
does
EPA
intend
to
incorporate
these
risks
into
the
methyl
bromide
risk
assessment
and
comparisons
conducted
in
the
cluster
rule?
The
Agency
has
included
an
assessment
of
UV­
related
skin
cancer
incidents
and
deaths
from
methyl
bromide
uses
conducted
by
the
Office
of
Atmospheric
Programs
(
OAP)
in
the
methyl
bromide
docket.
Stakeholders
are
encouraged
submit
comments
on
this
assessment.
The
results
of
this
assessment
will
be
considered
in
conjunction
with
the
current
OPP
assessment
in
determining
any
regulatory
action
related
to
methyl
bromide.

54
127
Application
Rates
and
Field
Sizes
for
Soil
Fumigation
­­
Human
Health
Risk
Assessment,
Pages
5
and
37
In
the
Human
Health
Risk
Assessment,
EPA
incorrectly
assumes
a
rate
of
430
lbs
of
ai/
acre
for
pre­
plant
soil
fumigation
for
all
uses.
However,
actual
application
rates
for
the
vast
majority
of
current
uses
are
considerably
lower
than
that.
For
example,
typical
application
rates
for
soil
uses
See
response
to
comment
#
1
are
below
200
lb/
acre.
Rates
above
this
amount
may
be
used,
but
only
in
rare
cases.
Moreover,
beginning
in
2005,
the
vast
majority
of
methyl
bromide
used
in
the
U.
S.
will
fall
under
Critical
Use
Exemptions
that
are
regulated
under
the
Federal
Clean
Air
Act
and
an
international
environmental
treaty
known
as
the
Montreal
Protocol.
The
Methyl
Bromide
Technical
Options
Committee,
an
international
technical
body
that
is
responsible
for
reviewing
all
Critical
Use
Exemptions
recently
reviewed
and
compiled
standard
use
presumptions
for
Critical
Uses.
The
standard
presumption
for
use
rate
for
soil
applications
was
20g
methyl
bromide
per
m
or
178
lbs
of
methyl
bromide
per
acre
in
standard
mixtures
of
methyl
bromide
­
chloropicrin
(
67:
33).
The
vast
majority
of
soil
applications
in
the
United
States
utilize
these
same
67:
3
3
mixtures.
Other
mixtures
with
lower
amounts
of
methyl
bromide
(
methyl
bromide/
chioropicrin
57:
43)
are
utilized
for
a
significant
portion
of
the
remaining
soil
applications.
Because
of
the
standards
set
by
the
Methyl
Bromide
Technical
Options
Committee,
future
allocations
of
Critical
Use
Exemptions
under
the
Montreal
Protocol
will
be
contingent
upon
a
use
rate
less
than
200
lb/
acre.
Thus,
it
is
wrong
for
EPA
to
assume
an
application
rate
of
more
than
double
that
amount
 
430
lb/
acre
 
when
assessing
future
risks
of
exposure
from
methyl
bromide
soil
applications.

Similarly,
EPA
continues
to
assume
a
maximum
soil
application
block
size
of
up
to
40
acres.
However,
the
typical
size
of
a
treated
field
is
10
acres.
Collected
data
on
actual
application
rates
and
field
sizes
in
California
(
the
State
with
the
highest
use
of
methyl
bromide)
confirm
that
typical
rates
are
well
below
EPA
assumption.

The
MBIP
queried
the
California
Pesticide
Use
Reporting
(
PUR)
Database
for
the
years
2001­
2003
for
all
soil
fumigations
in
which
methyl
bromide
was
used.
For
this
time
period,
the
average
application
rate
for
methyl
bromide
was
140
lb./
acre,

and
the
median
fumigation
block
size
was
9.7
acres.
Rates
and
application
block
sizes
reported
by
commercial
applicators
are
also
consistent
with
these
values.

The
PRA
should
assess
risks
on
the
basis
of
typical
rates
of
application
and
field
sizes
for
soil
fumigation.
Correction
factors
should
be
utilized
to
account
for
the
rare
use
of
higher
or
lower
rates.

55
127
Application
Rates
for
Commodity
Fumigation
 
Human
Health
Risk
Assessment,
Pages
49­
50
EPA
continues
to
assume
an
application
rate
for
post­
harvest
fumigation
of
9
lb/
I
000
ft
Actual
application
rates
for
the
vast
majority
of
commodity
fumigation
scenarios
are
much
lower,
ranging
from
0.75­
2.5
lb/
1000
ft
These
rates
are
specified
in
criteria
set
by
the
Technology
and
Economic
Assessment
Panel
(
TEAP),
an
international
technical
body
affiliated
with
the
Montreal
Protocol.
The
TEAP
criteria
for
post­
harvest
commodity
fumigations
call
for
a
maximum
dosage
of
20
g/
m
or
1.25
lb/
1000
ft
In
California,
actual
rates
of
application
reported
in
the
PUR
database
range
from
2
to
2.5
lb
methyl
bromide/
1000
ft
for
fresh
commodities.
Rates
for
fumigation
of
structures/
storage
areas
were
reported
as
0.75
to
1.5
lb
methyl
bromide/
1000
ft
As
in
the
case
of
soil
applications,
the
PRA
should
be
based
on
typical
application
rates.
Correction
factors
should
be
utilized
to
account
for
the
relatively
small
fraction
of
commodity
applications
are
conducted
at
higher
rates.
See
response
to
comment
#
1
Given
the
importance
of
methyl
bromide
as
a
crop
protection
tool,
EPNs
risk
determinations
must
be
accurate.
The
MBIP
urges
EPA
to
consider
the
data
presented
here
and
in
user
comments
submitted
on
the
PRA,
and
revise
its
risk
assessments
to
reflect
actual
use
practices
and
rates
of
application.

56
127
10X
Uncertainty
Factor
For
Lack
of
DNT
Study
­­
Pages
10­
12
EPA
continues
to
add
a
TOX
uncertainty
factor
for
the
lack
of
a
DNT
study
in
the
calculation
of
the
Human
Equivalent
Concentration
(
HEC)
for
the
acute
dietary
and
inhalation
exposure
scenarios.
The
MBIP
has
completed
a
DNT
study,
which
eliminates
the
need
for
the
additional
lox
factor.
The
HEC
used
in
the
PRA
increases
from
0.033
ppm
to
0.33
ppm
without
the
factor.
This
translates
into
buffer
zone
estimates
that
are
dramatically
different
than
those
presented
in
the
PRA.
An
interim
report
of
the
in­
life
phase
of
the
DNT
study
was
submitted
to
EPA
on
June
8,
2005.
A
meeting
to
discuss
the
preliminary
results
of
the
study
with
EPA
staff
was
held
on
June
15,
2005.
The
final
report
for
the
study,

including
neuropathological
evaluations,
was
submitted
to
EPA
on
October
5,

2005.
The
MBIP
urges
EPA
to
review
the
results
of
the
DNT
study
and
adjust
the
HEC
in
PRA
to
account
for
the
removal
of
the
tox
uncertainty
factor.
See
response
to
comment
#
35
57
127
Endpoints
for
Short­
and
Intermediate­
Term
Inhalation
Exposures
­­
Pages
10­
11
EPA
continues
to
use
a
sub­
chronic
inhalation
study
in
dogs
 
MRID
45722801
(
Schaefer
Study)
 
to
derive
the
endpoint
for
the
short­
and
intermediate­
term
inhalation
exposures.
As
noted
in
the
MBIFs
prior
comments,
the
Schaefer
Study
establishes
a
NOAEL
of
20
ppm.
The
Agency
continues
to
utilize
a
different
NOAEL
 
5.3
ppm
for
male
dogs
and
10
ppm
for
female
dogs.
The
MBIP
incorporates
its
previous
comments
and
submissions
on
this
issue
(
see
Attachments
1
and
2),
and
reiterates
its
request
that
EPA
reconsider
its
position
on
the
NOAEL
for
this
study.
The
Agency
concludes
that
the
effects
seen
at
the
10
and
20
ppm
concentrations
represent
part
of
the
doseresponse
curve
for
the
endpoint
identified
in
the
study
(
i.
e.,
lack
of
proprioceptive
placing).
Thus
the
Agency
reaffirms
its
conclusions
regarding
the
endpoint
and
point
of
departure
for
the
risk
assessments.

Ecological
risks
will
be
addressed
later
in
2006/
2007
along
with
the
pre­
plan
soil
uses
of
methyl
bromide.

58
127
Bystander
Exposure
and
Risk
From
Pre­
Plant
Agricultural
Use
 
PERFUM
Model
­­
Estimation
of
Flux
Rates
 
Pages
32­
45
The
MBJP
supports
EPA's
use
of
the
PERFUM
Model
to
estimate
nonoccupational
exposures.
Using
this
approach
leads
to
more
accurate
exposure
estimates
than
applying
the
ISCST3
model.
However,
there
is
a
serious
technical
flaw
in
the
way
EPA
has
calculated
the
flux
rates
that
were
used
in
the
PERFUIVI
modeling.
Compared
to
the
other
soil
fumigants,
methyl
bromide
has
an
extensive
array
of
field
studies
from
which
flux
rates
can
be
estimated.
In
the
PRA,
EPA
relies
on
work
done
by
the
California
Department
of
Pesticide
Regulation
(
CDPR)

to
generate
composite
flux
rate
profiles
(
i.
e.,
flux
rate
versus
time
since
application)
for
each
type
of
field
application
(
see
Johnson,
19992;
Johnson
and
Segawa,
2000
Johnson,
2004
This
work
was
not
intended
to
be
used
for
developing
flux
rate
profiles
and
certain
aspects
of
CDPR's
procedure
for
calculating
the
profiles
are
problematic
and
lead
to
the
overestimation
of
risk.

Under
CDPR's
approach,
a
mean
"
emission
ratio"
is
estimated
for
each
application
type
based
on
all
of
the
field
study
data.
The
emission
ratio
is
defined
as
the
percentage
of
methyl
bromide
mass
that
volatilizes
in
the
first
24
hours
after
the
application.
This
part
of
the
procedure
is
scientifically
sound
and
acceptable.

CDPR
then
develops
a
composite
decline
profile
for
methyl
bromide
that
is
meant
See
response
to
comment
#
41
to
reflect
the
proportion
of
mass
that
volatilizes
over
each
hour
since
the
start
of
the
application.
There
is
a
significant
technical
flaw
in
the
manner
in
which
EPA
is
using
this
aspect
of
CDPR's
analysis,
the
result
of
which
is
an
overestimation
of
buffer
zones.

The
technical
flaw
arises
from
the
decline
curves
developed
by
CDPR.
Those
curves
were
based
on
the
average
downwind
concentration
as
opposed
to
the
flux
rate.
While
there
is
a
correlation
between
these
two
parameters,
it
is
not
perfect.

For
example,
a
higher
flux
rate
is
needed
during
the
daytime
to
achieve
the
same
concentrations
near
the
field
as
during
the
nighttime,
due
to
the
more
conducive
dispersion
conditions
during
the
daytime.

The
problem
with
using
the
concentration
to
develop
a
decline
curve
for
the
flux
rate
is
illustrated
by
the
following
example.
Using
data
from
a
study
at
Seal
Beach,
California,
CDPR
developed
a
decline
curve
for
the
bedded
tarp
application
using
the
shank­
ahead
method
The
application
occurred
on
June
24,

1999.
The
decline
curve
is
reported
in
Johnson,
1999
(
see
Figure
A9).
Figure
1
below
reproduces
the
decline
curve
in
the
original
CDPR
report
and
plots
the
concentrations
and
flux
rates
using
the
mid­
point
of
the
measurement
interval.
The
concentration
values
(
triangle
symbol)
fall
very
close
to
the
decline
curve.
This
is
expected
since
the
concentration
values
were
used
to
estimate
the
decline
curve.

The
flux
rate
is
in
different
units.
Therefore,
it
was
plotted
on
a
separate
axis
and
the
peak
value
at
hour
3
was
matched
to
approximately
fall
on
the
decline
curve.

The
second
flux
rate
point
falls
substantially
below
the
decline
curve.
The
result
is
that
the
flux
rate
estimated
with
the
CDPR
decline
curve
is
much
higher
during
the
nighttime
period
than
actually
occurred
during
the
study.

To
illustrate
the
effect
of
the
poorly
specified
flux
rate
decline
curve,
the
MBIP
modeled
the
actual
flux
rate
data
from
the
Seal
Beach
shank­
ahead
study
to
compare
the
results
with
the
composite
curve
used
by
EPA.
Table
1
summarizes
the
flux
rates
for
the
Seal
Beach
study
and
the
composite
flux
rate
used
by
EPA,

both
scaled
to
an
application
rate
of
430
lbs/
acre.
Using
the
actual
data,
the
flux
rates
are
generally
higher
in
the
daytime
following
the
application.
However,

during
the
nighttime
period,
the
smoothed
flux
rates
are
several­
fold
higher
than
the
actual
flux
rates.
This
is
problematic
and
scientifically
unsound
because
the
atmosphere
is
less
conducive
to
dispersion
at
night,
and
placing
more
mass
in
the
nighttime
period
than
actually
occurred
results
in
an
overestimation
of
the
buffer
zones
as
shown
in
Figure
2.

Figure
2
presents
the
95
percentile
buffer
distances
for
both
the
whole
field
and
maximum
concentration
approaches
using
both
the
datasets
summarized
in
Table
1.
The
buffer
zones
using
the
actual
flux
rates
are
about
20%
lower
than
with
the
smoothed
flux
rates.
The
reason,
as
noted
above,
is
that
the
smoothed
flux
rates
artificially
place
more
mass
in
the
nighttime
period
than
actually
occurred
in
the
volatility
study.
In
the
PRA,
EPA
should
correct
this
issue
by
either:
(
1)
using
the
actual
flux
rates
in
the
modeling
as
was
done
for
all
of
the
other
fumigants,
or
(
2)

developing
a
smoothing
method
based
on
the
flux
rates,
and
not
raw
concentration
values.

59
127
Bystander
Exposure
and
Risk
From
Pre­
Plant
Agricultural
Use
 
PERFUM
Model
 
Whole
Field
v.
Maximum
Concentration
Approach
­­
Pages
36­
46
See
response
to
comment
#
41.
These
issues
have
also
been
considered
characterization
of
the
risks
for
methyl
The
Human
Health
Risk
Assessment
presents
results
from
the
PERFUM
model
based
on
twenty­
five
combinations
of
flux
and
meteorological
data
for
field
(

preplant
agricultural)
applications.
The
PERFUM
model
generates
two
statistical
distributions
of
buffer
zones
in
its
output
 
one
based
on
the
maximum
concentration
approach
and
the
other
based
on
the
whole
field
approach.
Both
are
presented
in
the
PRA.
For
the
maximum
concentration
approach,
the
direction
from
the
field
with
the
highest
concentration
is
selected
for
each
simulated
day
and
the
values
for
all
of
the
simulated
days
are
assembled
into
a
distribution.

Essentially,
this
represents
a
variability
distribution
around
the
maximally
exposed
individual
(
MEI),
except
that
in
this
case,
it
is
not
necessarily
known
that
there
is
an
individual
at
the
maximally
exposed
location.
In
fact,
given
the
sparse
population
near
many
applications,
the
odds
are
against
someone
being
right
at
the
maximum
concentration
location
(
and
for
all
24­
hours
after
the
application
as
EPA
assumed
for
methyl
bromide).

By
contrast,
the
whole
field
distribution
expands
upon
the
maximum
concentration
distribution
by
including
locations
in
every
direction
around
the
field,
not
just
the
direction
that
produces
the
maximum
concentration.
Therefore,

the
whole
field
distribution
is
essentially
a
population
distribution
at
the
buffer
zone.
It
represents
the
variability
in
exposure
at
the
perimeter
of
the
buffer
zone.

The
debate
between
using
the
whole
field
versus
the
maximum
concentration
approach
largely
falls
towards
what
is
meant
by
probabilistic
risk
assessment.

EPA
recently
explained
what
"
probabilistic
analysis"
means
in
its
Risk
Assessment
Principals
&
Practices.
There
it
stated
that
probabilistic
analysis
is
"
a
means
for
describing
the
uncertainty
in
risk
estimates
by
characterizing
the
uncertainty
and
population
variability
in
the
individual
steps
by
probability
distributions."
Only
the
whole
field
approach
represents
a
"
population
variability."
The
maximum
concentration
approach
only
represents
the
variability
in
exposure
of
a
single
individual,
the
ME
In
fact,
the
whole
purpose
of
probabilistic
risk
assessment
was
to
move
away
from
just
focusing
on
the
MEl.
In
other
OPP
assessments
such
as
for
dietary
exposure,
the
percentiles
used
for
regulation
define
population
variability.
Furthermore,
in
the
OP
cumulative
assessment
of
all
exposure
pathways,
the
percentiles
also
referred
to
a
population
variability.
For
all
of
these
reasons,
EPA
should
utilize
the
whole
field
approach
in
assessing
risks
of
exposure
to
methyl
bromide.

The
MBIP
believes
that
exposure
should
be
assessed
on
the
basis
of
a
population,

not
a
single
individual.
Although
specification
of
the
exposed
population
is
not
entirely
straightforward
given
the
nature
of
field
fumigation,
the
PERFUM
model
defines
the
population
in
the
most
constrained
way
possible.
The
population
only
includes
the
locations
around
the
buffer
zone
perimeter.
As
one
moves
away
from
the
perimeter,
the
concentrations
fall
and
defining
the
population
as
alternatively
being
some
distance
from
the
field
beyond
the
buffer
zone
would
have
resulted
in
smaller
values.
Going
the
other
way,
it
is
clearly
inappropriate
to
include
those
locations
inside
the
buffer
zone,
as
these
locations
will
be
protected
from
exposures
while
the
buffer
zone
is
in
place.
Therefore,
the
PERFUM
model
(
using
the
whole
field
approach)
defines
the
population
in
the
most
conservative
manner
possible.
bromide
and
other
fumigant
chemicals
and
they
will
be
given
due
consideration
in
any
regulatory
action.
60
127
Bystander
Exposures
from
Greenhouse,
Commodity,
Industrial
Facility
and
Residential
Use
 
Pages
46­
56
The
PRA
includes
an
assessment
of
bystander
exposures
and
risks
from
industrial
uses
(
i.
e.,
greenhouse,
commodity,
industrial
and
residential
applications).
The
Agency
acknowledges
that
the
PERFUM
model
provides
the
most
refined,

scientifically
defensible
approach
for
calculating
and
characterizing
risks.

However,
it
was
unable
to
utilize
the
PERFUM
mode!
for
the
industrial
uses
because
the
version
of
the
model
available
to
EPA
was
only
capable
of
providing
results
for
pre­
plant
agricultural
field
scenarios.
Thus,
by
default,
the
Agency
ran
the
ISCST3
model
for
these
industrial
scenarios
using
data
from
methyl
bromide
studies
conducted
by
the
California
Department
of
Pesticide
Regulation
(
CDPR).

The
PERFUM
model
has
been
updated
to
include
the
capability
to
model
these
types
of
application
scenarios.
PERFUM
2.0
allows
mode!
ing
of
raised
area
and
point
sources
using
the
PERFUM
framework.
In
the
remainder
of
this
section,
the
MBIP
demonstrates
how
PERFUM
2.0
can
be
used
to
estimate
buffer
zones
for
the
industrial
application
scenarios
using
the
assumptions
made
by
HED
in
the
PRA.
The
MBIP
urges
EPA
to
consider
these
results
in
assessing
potential
exposures
associated
with
the
use
of
methyl
bromide
for
fumigation
of
greenhouses,
potting
soil,
commodities,
residential
buildings
and
industrial
buildings.
The
Agency
revised
assessment
for
commodity
uses
is
now
based
on
the
PERFUM
model
and
has
incorporated
these
comments
as
appropriate.

61
127
In
reviewing
the
EPA
modeling
files,
the
MBIP
identified
several
issues:

°
EPA's
Model
Does
Not
Account
for
24­
hour
Toxicity
Averaging
Time.
The
most
significant
issue
with
EPA's
modeling
in
the
PRA
is
that
it
does
not
account
for
the
24­
hour
toxicity
averaging
time
for
methyl
bromide
for
the
commodity
aeration
scenarios.
For
emission
periods
less
than
24­
hours
(
e.
g.,
15
minutes
or
1
hour),
EPA
calculated
a
result
for
that
smaller
time
period,
but
did
not
adjust
the
result
to
match
the
toxicity
averaging
period
of
24
hours.
This
mismatch
results
in
a
100­
fold
underestimation
of
the
MOE's
(
i.
e.,
overestimation
of
risk)
for
the
"
Commodity
Aeration
with
No
Stack"
and
"
Commodity
Aeration
with
Minimal
Stack"
scenarios.

°
EPA
Assumes
the
Wrong
Release
Height.
For
the
commodity
fumigation
scenarios,
EPA
used
3
feet
as
the
release
height
for
all
of
the
building
area
sources.
According
to
the
dimensions
of
the
250,000
ft
building
used
by
EPA,
the
building
should
be
25
feet
tall
given
the
lOOxlOO'
base
assumed
by
EPA.

Therefore
the
release
height
does
not
match
the
building
dimensions
(
although
CDPR
found
that
lower
heights
worked
better).
According
to
CDPR
(
CDPR
1994),
using
a
release
height
of
3
feet
overestimated
the
concentrations
when
attempting
to
model
a
building
fumigation.
Therefore,
a
release
height
equal
to
half
of
the
building
height
(
based
on
area
and
volumes
used
in
EPA'
s
modeling)

was
used,
to
account
for
the
fact
that
not
all
of
the
fumigant
will
be
released
from
the
top
of
the
building.

°
EPA
Assumptions
on
Building
Downwash
are
Unexplained
and
Unwarranted.

EPA
used
an
ISC
algorithm
for
modeling
building
downwash
for
the
aeration
with
stack
scenario,
which
is
when
a
nearby
building
influences
the
air
dispersion
from
a
source
by
altering
the
airflow
pattern
in
the
vicinity
of
the
source.
Inexplicably,

EPA's
downwash
building
height
was
higher
than
the
stack.
There
is
no
See
response
to
comment
#
25,
26,
60.
In
the
updated
assessment
a
variety
of
inputs
have
been
considered.

Complete
modeling
inputs
and
output
files
can
be
provided
for
consideration
by
stakeholders.
Much
of
the
factors
considered
in
this
comment
have
been
updated
based
on
newly
available
use
information
and
the
modification
of
the
PERFUM
model
for
use
in
commodity
assessments.
discussion
in
the
risk
assessment
of
this
assumption,
and
it
appears
unwarranted.

The
MBIP
disputes
the
inclusion
of
building
downwash
in
the
modeling.

62
Although
there
are
several
issues
to
be
resolved,
the
MBIP
urges
EPA
to
step
back
and
carefully
consider
the
PERFUM
2.0
approach
to
estimating
potential
exposures
from
building
fumigations.
The
MBIP
is
committed
to
work
with
the
Agency
to
develop
an
adequate
solution
to
these
complex
problems
so
that
PERFUM
2.0
can
be
utilized
to
improve
the
accuracy
of
assessments
for
these
application
scenarios.
See
response
to
comment
#
25,
26,
60
63
127
HUMAN
HEALTH
RISK
ASSESSMENT
­­
Occupational
Exposure
 
Pre­
Plant
and
Field
Fumigation
In
the
PRA
at
pages
69­
71
and
Appendix
T,
EPA
presents
the
results
of
its
assessment
of
potential
occupational
exposures
and
risks
associated
with
pre­
plant
agricultural
field
fumigation.
In
the
PRA,
all
of
the
data
on
worker
exposures
are
taken
from
studies
performed
in
the
State
of
California.
Thus,
the
Agency's
entire
analysis
of
risk
for
these
workers
rests
solely
on
California
exposure
data.
As
a
result,
it
is
critical
that
the
exposure
data
be
placed
in
the
historical
framework
of
the
use
of
methyl
bromide
in
California.

The
Agency
has
not
done
this
and
has
in
fact
treated
all
measurements
of
exposure
with
absolutely
no
consideration
of
the
historical
context
of
the
studies
in
which
they
were
reported.
This
failure
to
properly
interpret
the
California
data
is
the
primary
reason
for
the
Agency's
conclusion
that
current
exposures
pose
unacceptable
risks.
A
proper
evaluation
using
corrected
data
leads
to
the
conclusion
that
current
exposures
are
safe.
The
PRA
also
presents
a
risk
characterization
that
is
fraught
with
errors.
These
errors
occurred
in
both
the
exposure
and
risk
characterization
processes.
These
errors
have
further
obscured
the
context
of
the
exposures.
See
response
to
comment
#
41.
Stakeholders
are
also
encouraged
to
submit
additional
data
which
better
aligns
with
their
current
situation
which
would
allow
for
a
more
refined
risk
assessment.
At
this
time,
the
vast
majority
of
all
methyl
bromide
data
have
been
generated
in
California
so
it
is
not
possible
to
more
accurately
represent
conditions
in
other
geographic
regions
such
as
the
mid­
atlantic
or
upper
midwest.

64
127
Overview
of
Errors
and
Flaws
In
EPA's
Analysis
of
Pre­
plant
and
Field
Fumigation
Workers
Available
data
on
worker
exposure
and
the
proper
use
of
methyl
bromide
toxicity
data
indicate
that
current
risks
are
significantly
lower
than
the
estimates
given
in
the
PRA.
As
a
threshold
issue,
the
MOE
calculations
presented
in
Table
6
of
the
Agency's
"
Overview"
document
and
Table
20
in
the
Revised
Human
Health
Risk
Assessment
(
June
13,
2005)
appear
to
be
incorrect.
It
appears
that
the
Agency
applied
a
Human
Equivalent
Concentration
(
HEC)
of
10
ppm
to
calculate
the
MOE
for
both
the
acute
and
the
short­
and
intermediate­
term
scenarios.
However,
this
HEC
value
does
not
match
the
HEC
concentrations
for
these
occupational
scenarios
that
are
presented
in
Table
2
in
the
"
Overview"

document
(
Table
4
in
the
Revised
Human
Health
Risk
Assessment).
For
acute
occupational
exposure,
the
HEC
is
reported
as
30
ppm
(
not
10
ppm)
and
the
required
MOE
is
30.
In
essence,
this
is
equivalent
to
an
acceptable
acute
human
exposure
concentration
of
1
ppm.
It
also
appears
that
the
acute
and
the
short­
and
intermediate­
term
exposure
concentrations
for
"
All
Workers
at
Field
Application"

are
in
error.

As
stated
in
the
introduction
of
this
section,
the
Agency's
analysis
is
based
solely
on
data
from
workers
in
the
State
of
California.
Based
on
that
data,
the
Agency
concludes
that
all
of
the
job
classifications
evaluated
in
the
assessment
fail
the
1
ppm
risk
criterion.
However,
in
California,
soil
applications
are
currently
being
See
response
to
comment
#
41
conducted
to
meet
a
210
ppb
24­
hour
TWA
standard.
This
standard
has
been
set
by
the
California
Department
of
Pesticide
Regulation
(
CDPR)
and
is
applicable
to
all
workers.
The
standard
has
the
effect
of
placing
a
cap
on
the
exposures
that
occur
in
any
8­
hour
period.
The
highest
amount
of
exposure
that
can
occur
in
this
shorter
period
is
three
times
the
24­
hour
standard
or
630
ppb
(
0.63
ppm).
Methyl
bromide
applications
in
California
currently
meet
this
standard.
Therefore,
EPA
should
expect
that
data
from
California
would
support
a
finding
that
current
exposures
do
not
exceed
0.63
ppm,
and
as
a
result,
that
current
exposures
also
will
not
exceed
the
higher
health
criterion
of
1
ppm.

Despite
the
fact
that
the
soil
fumigation
industry
is
meeting
the
more
stringent
standard,
EPA
has
determined
in
the
PRA
that
the
available
data
indicate
that
all
seven
jobs
classifications
associated
with
soil
fumigation
pose
unacceptable
risks.

The
Agency
is
led
to
this
conclusion
because
it
has
failed
to
account
for
current
practices
that
control
exposure.
The
root
of
this
error
is
the
Agency's
use
of
monitoring
data
that
dates
back
to
1981.
Prior
to
1992,
the
standards
for
exposure
were
15
ppm
and
as
a
result,
levels
of
exposure
above
I
ppm
were
permitted
in
the
1980s.
Application
practices
have
changed
since
the
1
980s
and
current
exposures
are
lower.
Modifications
currently
in
place
in
California
that
reduce
current
exposures
include:

°
Reduction
of
the
application
rates;

°
Changes
in
applications
methods
(
improved
injection
designs,
rapid
closure
of
injection
shank
furrows,
and
separation
of
tarp
cutting
and
tarp
removal
processes)

that
minimize
the
amount
of
methyl
bromide
that
is
released;

°
Use
of
high
barrier
tarps;

°
Modification
of
tractors;
and
°
Use
of
ventilation
fans
in
the
tractor
cabs.

Because
the
worker
monitoring
data
from
the
1990s
is
more
recent
and
because
of
the
documented
changes
in
engineering
practices
data
from
the
1
980s,
the
studies
performed
in
the
1980s
should
not
be
used
in
the
PRA.
A
second
problem
with
the
Agency's
analysis
is
that
it
has
included
all
of
the
data
from
studies
of
engineering
controls
where
the
above
technologies
have
been
demonstrated.
These
data
included
the
"
control"
data
where
the
technology
was
not
applied.
If
EPA
had
limited
measurements
used
in
these
studies
to
the
data
that
reflect
the
current
controls,
the
results
would
indicate
that
workers
are
not
exposed
to
unsafe
levels.

While
the
decision
to
include
monitoring
data
that
do
not
reflect
current
practices
is
the
major
reason
for
EPA's
finding
of
unacceptable
risk,
the
PRA
also
contains
a
large
number
of
factual
errors
in
the
compilation
of
monitoring
data
from
the
California
studies.
These
errors
include:

°
Errors
in
the
citation
of
studies;

°
Failure
to
include
all
of
the
data
in
a
given
study;

°
Duplicative
citations
of
the
same
data;

°
Inclusion
of
studies
for
pests
that
are
not
supported
by
current
labels
(
ground
squirrels);

°
Misapplying
data
to
the
wrong
job
classifications.

These
errors
are
outlined
below.
In
preparing
these
comments,
the
MBIP
has
sought
to
correct
the
data
and
to
provide
a
more
accurate
characterization
of
the
currently
available
studies.
A
corrected
data
set
is
presented
in
Attachment
4.

Aside
from
these
errors,
EPA
has
failed
to
interpret
properly
the
available
monitoring
data
in
several
respects.
These
errors
include:

1.
EPA
does
not
give
equal
weight
to
data
from
studies
from
the
early
1980s
that
are
not
representative
of
current
exposures
and
data
from
more
recent
studies.

2.
EPA
incorrectly
gives
equal
weight
to
samples
taken
with
and
without
controls.

3.
EPA
incorrectly
gives
equal
weight
to
short
term
measurements
(
30
mm.
and
less
in
duration)
and
measurements
over
an
entire
working
day.

4.
EPA
assessment
fails
to
consider
the
impact
of
reduced
application
rates
and
other
mitigation
measures
already
in
use
in
California
on
current
exposures.

These
points
are
discussed
in
detail
below.

Finally,
this
assessment
has
focused
on
the
impacts
of
a
proper
interpretation
of
the
toxicity
and
exposure
for
acute
risks,
specifically
whether
workers
in
2005
will
be
exposed
to
levels
above
1
ppm
8
h
TWA
on
any
given
day.
The
comments
have
focused
on
the
acute
risks
because
these
are
the
risks
that
the
PRA
identified
as
being
of
the
greatest
concern.
However,
the
proper
evaluation
of
the
exposure
studies
described
below
will
also
result
in
lower
estimates
of
short/

intermediateterm
and
long­
term
exposures.
These
lower
estimates
also
result
in
acceptable
risks
for
these
toxicological
endpoints
without
the
need
for
respirators.

65
127
Errors
and
Data
Related
Issues
in
the
PRA
Analysis
The
MBIP
found
numerous
errors
in
the
data
underlying
the
Agency's
analysis.

These
errors
were
not
evident
in
the
prior
rounds
of
the
error
correction
phase
because
the
underlying
data
have
only
now
been
made
available.
Thus,
this
is
the
first
opportunity
that
the
MBIP
has
had
to
discover
them.

As
more
fully
detailed
below,
the
errors
in
the
data
are
numerous.
For
ease
of
reference,
the
errors
are
organized
based
on
the
study
names
as
listed
in
the
bibliography
to
the
PRA
(
Appendix
C).
In
the
tables
provided
in
Appendix
T,
16
studies
are
listed
as
contributing
data
to
the
PRA
(
Field
3,
4,
5,
7,
16,
18,
20,
21,

21,
23,
38,
39,
49,
and
50).
Three
studies
have
duplicate
listings
(
Field
22
is
also
Field
40,
Field
38
is
also
Field
41,
and
Field
49
is
also
Field
50).
Thus
there
are
actually
only
13
named
studies,
not
16.
In
addition,
as
the
following
indicates,
the
names
on
the
actual
documents
do
not
necessarily
match
up
with
the
names
in
the
bibliography.

°
Field
4.
Siemer
and
Associates,
Inc.
(
1992c)
AMBI:
Shallow
Shank­
Tarped
Bed
Fumigation
Assessment
(
Interim
Report
No.
SM924096C,
M).

This
"
study"
consists
of
two
reports.
The
EPA
analysis
omits
data
from
the
second
of
the
two
reports.
In
this
analysis
these
data
are
included.
This
adds
19
additional
measurements
to
the
database.
As
discussed
below,
the
missing
data
also
provide
information
on
how
commonly
used
controls
reduce
worker
exposures
in
the
fumigation
of
beds.

In
addition,
the
data
from
Siemer
and
Associates,
Inc.
(
1992c)
on
Shovelman
(
Table
4
of
the
study)
were
not
used
in
the
EPA
analysis.
The
MBIP
used
these
data
in
the
assessment
summarized
below.
Data
on
the
job
that
EPA
labeled
as
"
Plastic
Truck
Driver"
are
included
in
the
"
Second
Driver"
job.
However,
the
"
Second
Driver"
appears
to
be
intended
to
cover
workers
in
vehicles
that
follow
See
response
to
comment
#
41
the
tractor
pulling
the
methyl
bromide
injection
equipment.
These
vehicles
can
include
tractors
laying
tarps
and
pulling
cultipackers,
but
they
do
not
include
the
"
Plastic
Truck
Drivers".
These
drivers
bring
the
tarps
to
the
work
site
but
do
not
enter
the
fields.
Therefore
these
workers
should
not
be
included
in
the
"
Second
Driver"
job.
The
data
in
this
study
is
also
reported
under
Field
39.

°
Field
5.
Maddy,
K.;
Lowe,
J.;
Fredrickson,
S.
(
1984)
Employee
Exposure
To
Methyl
Bromide
Used
For
Ground
Squirrel
Control:
HS­
1238.
Unpublished
study
prepared
by
California
Dept.
of
Food
&
Agriculture,
l3p.

This
study
reports
on
exposures
that
occur
from
the
control
of
ground
squirrels.

The
registrants
no
longer
support
this
use.
In
addition,
the
method
of
application
is
so
different
from
soil
fumigation
(
squirting
methyl
bromide
down
a
burrow
by
hand)
that
the
data
are
not
a
relevant
measure
of
agricultural
worker
exposures
from
soil
fumigants.
The
data
from
this
study
should
not
be
included
in
the
PRA.

°
Field
18.
Maddy,
K.;
Gibbons,
D.;
Lowe,
S.;
et
al
(
1984)
A
Study
Of
the
Inhalation
Exposure
of
Workers
to
Methyl
Bromide
during
Preplant
Soil
Fumigation
(
Shallow
Injection)
in
1980
and
1981:
HS­
900.
Unpublished
study
prepared
by
California
Dept.
of
Food
and
Agriculture,
Div.
of
Pest
Management,

Environmental
Protection
and
Worker
Safety,
Worker
Health
and
Safety
Unit.

37p.

The
name
of
the
studies
that
provide
the
data
listed
under
Field
18a­
e
in
the
Tables
in
Appendix
I
is
incorrectly
listed
in
Appendix
C.
The
data
in
Field
18
are
taken
from
three
sources.
Two,
and
possibly
three
of
these
sources
are
from
studies
other
than
the
one
cited
for
Field
18.
The
first
set
of
data
listed
as
18a
comes
from
a
1982
Study
by
Maddy
(
A
Study
of
the
Inhalation
Exposure
of
Workers
to
Methyl
Bromide
During
Preplant
Soil
Fumigants
(
Shallow
injection)

in
1980
and
1981.)
The
second
set
of
data,
listed
as
I
8b
comes
from
an
unreferenced
table
described
as
"
preliminary
results
 
for
review
and
discussion
only."
The
table
does
not
include
any
supporting
information
on
the
origin
of
the
data
or
the
date
that
it
was
collected.
The
third
set
of
data,
listed
as
1
8c­
e,
is
a
series
of
internal
studies
from
TriCal
Inc.
collected
by
Donald
Richmond
of
the
State
of
California.
This
set
of
data
is
presented
later
as
part
of
the
data
entered
as
Field
49.

The
data
from
the
first
two
sources
(
labeled
1
8a
and
1
8b)
are
used
to
evaluate
the
Driver,
Co­
pilot,
and
Shovelman
job
classifications.
The
data
from
all
three
sources
(
labeled
1
8a,
1
8b,
1
8c,
1
8d,
and
1
8e)
are
used
in
the
determination
of
"
All
Workers
at
Field
Application."
In
the
corrected
analysis
presented
below,

only
the
data
from
the
first
source
is
used.
The
data
from
the
second
source,
the
1984
table,
should
not
be
used
since
the
table
lacks
any
description
on
where
the
data
originates,
how
it
was
collected,
and
how
the
values
were
calculated.
Finally
these
data
are
described
as
preliminary.
The
data
from
the
third
source
appear
to
be
a
subset
of
the
data
presented
in
Field
49
and
are
entered
under
that
Field
number.

°
Field
19.
Gillis
M.
Becker
(
1994
c)
Report
on
New
High
Barrier
Film
Evaluation
Studies,
TC233
1,
TC233
2
and
TC233
3,
TRICAL
Inc.

This
study
is
not
listed
in
Appendix
C
but
is
listed
in
Appendix
T.

°
Field
20.
TriCal,
Inc.
(
1993a)
Tarp
Removal
Worker
Exposure
Vol.
1­
2
(
TC211).

EPA
used
a
measurement
of
Tarp
Puller
exposure
that
reflects
a
technical
problem
in
the
field
and
is
not
representative
of
typical
tarp
remover
exposures.
This
data
point
should
be
removed
from
EPA
analysis.

°
Field
22
(
Also
listed
as
Field
40).
Siemer
and
Associates,
Inc.
(
1993b)
Deep
Shank,
Nontarped
Fumigation­
Mitigation
of
Methyl
Bromide
Worker
Exposure
and
Offsite
Drift
(
Interim
Report
No.
SM934104,
1­
2,
Report
No.

SM934104.2­
1,
Vol.
1­
2).

Data
from
this
study
are
listed
under
Fields
22
and
40
in
the
RED.
Thus
the
data
are
double­
counted
in
the
EPA
analysis.
In
the
MBIP's
corrected
analysis,
these
data
are
entered
only
once
under
the
heading
of
Field
22.

°
Field
39.
Siemer
and
Associates,
Inc.
(
1992b)
Nontarp
Deep
Injection
for
Measurement
of
Methyl
Bromide
Exposure
to
the
Applicator,
Applicator
Assistant,
and
Cultipacker
Tractor
Driver
(
Interim
Report
No.
SM924096B).

This
Field
is
mislabeled
in
Appendix
C.
The
data
for
Field
39
actually
comes
from
the
study,
Siemer
and
Associates,
Inc.
(
1992c)
AMBI:
Shallow
Shank­
Tarped
Bed
Fumigation
Assessment
(
Interim
Report
No.
SM924096C,
M).
The
data
from
Siemer
and
Associates,
Inc
(
1992c)
is
already
entered
into
the
PRA
analysis
under
Field
4.

In
the
corrected
analysis
presented
below,
the
data
from
Siemer
and
Associated,

Inc
(
1
992c)
is
removed
from
the
Field
39
entry
and
is
replaced
with
the
data
from
Siemer
and
Associates,
Inc.
(
1992b).

°
Field
49
(
Also
listed
as
Field
50).
TriCal,
Inc.
(
1987)
Response/
California
Notice
87­
5:
Risk
Assessment/
Methyl
Bromide.
DPN
123­
099.
Record
No.
64748
to
64753.

Field
49
is
incorrectly
listed
in
Appendix
C.
It
is
actually
an
interoffice
memo
dated
1981
(
Great
Lakes
Chemical
Corporation,
(
1981)
Interoffice
Memorandum
From
D.
L.
McAllister
to
R.
J.
McKeand,
Subject
Methyl
Bromide
 
Applicator
Exposures)
and
is
composed
of
a
series
of
data
sheets
on
worker
monitoring.

A
number
of
errors
were
identified
in
the
transcription
of
the
data.
The
EPA
analysis
failed
to
use
data
labeled
"
Swamper."
This
is
an
alternative
name
for
copilot
These
data
have
been
included
in
the
corrected
data
as
part
of
the
co­
pilot
data.
The
data
on
tarp
cutters
was
also
omitted.
These
data
are
also
included
in
the
MBIFs
analysis.

Field
50
is
also
incorrectly
listed
in
Appendix
C
and
differs
from
the
TriCal
Inc.

(
1987)
reference.
The
data
actually
come
from
a
document
defined
as
"
Results
of
Worker
Monitoring
of
Deep
Tarpless
Application
at
Various
Sites
in
CA,
by
Rick
Stange
Sponsored
by
TriCal,
04/
03/
1986."

A
measurement
point
from
a
grab
sample
taken
when
an
applicator
fixed
a
connection
is
listed
as
an
applicator
exposure.
This
measurement
is
too
short
a
duration
(
1
minute)
to
be
indicative
of
the
8
hr
TWA
exposures.
This
data
point
should
not
be
used
EPA's
analysis.

Finally
it
is
unclear
why
a
"
Shovelman"
exposure
is
reported
when
the
study
is
described
as
Tarpless.

°
Additional
Errors
­­
Miscellaneous
In
Appendix
T,
EPA
Lists
the
same
data
from
Field
4
under
both
the
"
Second
Tractor
Driver"
and
"
Irrigation
Worker"
job
classifications.
This
is
incorrect.
In
the
MBIP's
reanalysis,
the
data
have
been
listed
under
"
Irrigation
Worker."

66
Temporal
Trends
in
Worker
Exposures
Due
to
Improved
Technology
The
available
monitoring
data
on
worker
exposure
levels
present
a
strong
case
that
technological
changes
in
California
have
greatly
reduced
exposure
to
methyl
bromide
over
the
period
of
1981
to
1994.
The
following
figure
presents
the
maximum
values
for
each
of
the
seven
job
classifications
as
given
by
each
of
the
available
monitoring
studies.
Where
a
study
demonstrates
the
use
of
a
technology
that
is
now
in
common
use
in
California,
only
the
data
from
the
samples
that
reflect
the
use
of
that
technology
are
presented.
Thus,
in
Field
4
only
data
from
the
fields
that
used
the
rapid
closure
technology
(
closing
shoes
followed
by
a
roller
that
compacts
the
soil
prior
to
tarp
placement)
are
used'.
In
Field
23
only
data
from
the
fields
treated
with
a
noble
plow
are
used.
As
the
figure
shows
there
is
a
strong
trend
of
reduced
exposure
over
time.
Data
from
the
early
1990s
indicates
that
when
controls
are
used,
most
of
the
jobs
are
below
1
ppm.
This
finding
is
expected
because
CDPR
lowered
the
permissible
exposure
to
Methyl
Bromide
to
a
24­
hour
TWA
of
210
ppb
in
the
early
1990'
s.
See
response
to
comment
#
41
67
127
Changes
in
Engineering
and
Practice
In
the
1980s
a
number
of
engineering
practices
in
soil
fumigation
were
modified
to
reduce
exposures.
Some
of
these
practices
were
captured
in
s
guidance
on
the
use
of
methyl
bromide
When
methyl
bromide
is
injected
into
soil
the
injection
is
performed
by
a
series
of
injections
at
the
bottom
of
the
shanks
of
plows
pulled
behind
a
tractor.
The
tractor
pulls
the
application
equipment
across
a
field.
Once
the
equipment
reached
the
end
of
the
field,
the
plows
and
injection
equipment
must
be
raised
to
allow
the
tractor
to
swing
around
and
begin
plowing
the
next
section
of
the
field.
In
the
early
1980s
the
practice
was
to
shut
off
the
supply
of
methyl
bromide
into
the
injection
equipment
prior
to
raising
the
plows.
This
was
done
using
a
"
shut­
off
valve."
This
prevented
the
spraying
of
methyl
bromide
into
the
air
when
the
injection
shanks
were
in
a
raised
position.
However,
a
substantial
amount
of
methyl
bromide
remained
in
the
tubes
leading
down
to
the
shanks.
This
residual
methyl
bromide
in
the
injection
equipment
would
escape
during
the
time
the
tractor
repositioned
itself
and
began
plowing
the
next
portion
of
the
field.
These
releases
occurred
each
time
the
tractor
reached
the
end
of
the
field
and
resulted
in
increased
exposures
to
all
employees
at
the
site.

In
the
mid
1980s,
the
injection
equipment
was
modified
to
allow
compressed
air
to
flush
the
methyl
bromide
from
the
shanks
prior
to
lifting
the
shanks
from
the
soil.
This
flushing
was
performed
after
the
cutoff
valve
was
closed
and
before
the
shanks
were
raised
from
the
soil.
As
a
result,
methyl
bromide
is
not
released
to
the
air.

A
second
modification
that
also
occurred
during
this
period
was
the
requirement
that
engine
fans
of
the
tractor
blow
back
towards
the
injection
equipment.
Prior
to
this
modification
certain
types
of
tractors
used
to
pull
the
injection
equipment
(
Caterpillar
tractors)
had
fans
that
pulled
air
from
the
rear
of
the
tractor
over
the
engine
and
blew
the
air
out
of
the
front
of
the
vehicle.
This
practice
"
pulled"
air
See
response
to
comment
#
41
over
the
injection
equipment
and
carried
the
methyl
bromide
towards
the
driver
and
co­
pilot.
In
the
mid
1980s,
this
mechanism
of
exposure
was
identified
and
the
tractors
were
modified
to
blow
air
from
the
front
of
the
tractor
back
across
the
engine
to
the
rear
of
the
tractor.
This
caused
any
methyl
bromide
released
from
the
injection
equipment
to
be
blown
away
from
the
driver
and
co­
pilot
and
resulted
in
reduced
exposures
to
these
jobs.

In
addition
to
these
changes,
in
the
early
1
990s
CDPR
required
the
use
of
tarps
with
low
permeability
to
Methyl
Bromide'
Specifically
these
regulations
require
that
tarps
used
for
methyl
bromide
soil
fumigations
in
California
shall
have
a
permeability
factor
between
5
and
8
milliliters
per
hour
per
square
meter
per
1000
ppm
of
methyl
bromide
at
30
degrees
Celsius
and
be
approved
by
the
Department.

Tarps
used
prior
to
this
time
had
much
higher
permeability
and
as
a
result
general
air
levels
at
treated
fields
were
higher
in
the
1980s
than
after
the
1990s.

68
127
Decreased
Application
Rates
will
Reduce
Occupational
Exposures
The
existing
monitoring
data
are
all
more
than
12
years
old.
Typical
application
rates
of
Methyl
Bromide
are
now
significantly
lower
then
the
levels
in
the
monitoring
studies
performed
in
the
1980s
and
1990s.
As
discussed
in
Section
II
above,
typical
rate
for
soil
fumigation
are
now
below
200
lb/
acre.
As
the
data
in
Attachment
4
shows,
almost
all
of
the
monitoring
data
utilized
by
EPA
in
the
PRA
reflects
usage
rates
from
greater
than
200
lbs/
acre
and
includes
data
from
fields
where
the
application
rates
were
as
high
as
400
lbs/
acre.

The
role
of
application
rates
as
a
factor
in
methyl
bromide
exposure
has
been
discussed
by
a
number
of
authors
(
Maddy
et
al.
Abdalla
et
al.'
and
higher
levels
of
exposure
are
believed
to
occur
when
application
rates
are
high.
Quantitative
evidence
of
the
role
of
application
rate
and
air
concentrations
can
be
seen
in
the
monitoring
data.

In
Field
23
(
Siemer
and
Associates,
Inc.,
1992a),
First
Tractor
Drivers,
Co­
Pilots,

and
Shovelman
were
monitored.
The
purpose
of
the
study
was
to
demonstrate
the
reduction
of
exposure
from
the
use
of
the
Nobel
plow.
However,
as
the
following
three
figures
show
the
exposures
to
all
three
jobs
declines
as
the
application
rates
decline.
This
decline
occurs
for
both
types
of
plow.
These
data
show
that
as
the
application
rates
approach
200
lbs/
acre,
the
measured
exposures
to
methyl
bromide
drop
to
less
than
0.5
ppm
for
all
three
jobs.

Similar
patterns
can
be
seen
in
other
studies.
The
finding
that
concentrations
drop
with
application
rates
indicates
that
the
current
use
rates
of
methyl
bromide
result
in
lower
exposures
than
the
studies
from
the
1980s
and
1990s
indicate.
Since
the
studies
from
the
1990s
indicate
that
uses
in
the
range
of
200­
400
lbs
can
meet
the
current
1
ppm
criterion,
future
levels
of
exposure
are
likely
to
be
well
below
1
ppm.
See
response
to
comment
#
41
69
127
Use
of
Short
Term
Data
to
Predict
8­
hour
TWA
In
the
PRA,
EPA
has
assumed
that
the
air
concentrations
reported
by
the
authors
of
the
various
studies
can
be
assumed
to
be
predictors
of
8
hr
TWA.
This
is
incorrect.
The
range
of
sampling
times
for
these
measurements
has
ranged
from
less
than
30
minutes
up
to
six
hours
with
the
majority
of
the
samples
less
than
three
hours
in
duration.
Since
short­
term
sampling
is
taken
at
those
times
where
the
potential
for
exposure
is
the
highest,
the
values
reported
may
be
higher
than
See
response
to
comment
#
41
the
8­
hour
TWA
exposure
received
by
the
worker.
This
occurs
for
two
reasons.

First,
if
the
sample
was
taken
over
a
period
of
relatively
high
exposure
(
correction
of
a
malfunction
of
a
piece
of
equipment)
then
the
measurement
could
over
estimate
the
average
exposure
during
the
time
of
injection.

Second,
any
measure
of
exposure
taken
during
the
time
of
actual
injection
of
methyl
bromide
will
overestimate
the
8­
hr
TWA,
since
methyl
bromide
is
not
injected
for
8
hours
a
day.
Soil
fumigation
requires
that
large
pieces
of
equipment
be
transported
to
the
site
of
the
soil
fumigation.
Once
there,
equipment
preparation
and
set
up
requires
approximately
1
­
1.5
hours.
Application
of
methyl
bromide
must
cease
during
lunch.
At
the
end
of
the
day
shut
down
and
removal
processes
require
approximately
1
hour.
Thus
in
a
nine
hour
working
day
only
5.5
hours
of
injection
occurs
(
personal
communication
Tom
Dufala,
2005).

Evidence
that
applications
occur
for
less
than
8
h
per
day
can
be
seen
in
the
sampling
times
from
a
number
of
the
recent
surveys
where
workers
were
monitored
for
an
entire
injection
period.
The
durations
in
these
surveys
are
typically
in
the
range
of
4­
5
hours.
Additional
evidence
for
a
5.5
h
injection
time
is
seen
in
a
1998
study
that
investigated
the
temporal
patterns
of
worker
exposure
in
the
methyl
bromide
soil
fumigation
industry
(
MBIP,
1998'
s).
In
this
study,
data
on
the
number
of
acres
treated
by
each
of
47
workers
in
each
month
of
a
1
2­

month
period
(
May
1997­
April
1998)
was
analyzed.
The
time
necessary
to
treat
an
acre
and
the
assumption
the
injection
time
will
be
limited
to
5.5
hrs
per
day
were
used
to
solve
for
how
many
days
in
the
month
the
worker
was
injecting
methyl
bromide.
In
every
case,
the
total
number
of
acres
treated
in
a
given
month
by
a
worker
did
not
exceed
the
number
that
could
be
treated
in
a
5.5
hr
workday
(
given
a
5­
6
day
workweek).

For
both
of
these
reasons
the
finding
that
a
specific
sample
is
greater
than
1
ppm
cannot
be
taken
as
evidence
that
the
worker
has
had
an
8
hour
TWA
exposure
of
greater
than
1
ppm.

70
127
Comments
on
Specific
Job
Classifications
in
the
PRA
EPA
establishes
seven
job
classifications
in
its
assessment
of
soil
fumigation
exposures.
The
following
section
presents
the
specific
comments
on
these
seven
job
classifications.
As
the
comments
indicate,
two
of
the
jobs
classes
(
second
tractor,
and
irrigation
worker)
should
be
dropped.
As
the
comments
indicate
MIBP
believes
that
the
available
data
indicate
that
the
current
exposures
for
the
remaining
five
jobs
are
not
likely
to
exceed
1
ppm.

°
First
Tractor
Driver
There
is
a
large
amount
of
data
for
the
First
Tractor
Driver
or
Applicator.
As
data
on
historical
trends
indicates,
the
exposures
to
methyl
bromide
for
this
job
have
been
reduced
to
levels
below
1
ppm
in
the
early
1990s.
This
reduction
was
achieved
by
improved
injection
methods,
use
of
high
barrier
films,
modifications
in
the
engine
fans,
and
the
introduction
of
ventilation
fans
in
the
driver's
cabin.

Moreover,
current
levels
are
expected
to
be
lower
than
the
levels
in
the
studies
from
the
early
1
990s
since
application
rates
have
declined
over
the
last
10
years.

°
Co­
pilot
The
co­
pilot's
exposure
tends
to
be
more
variable
than
the
driver's
reflecting
the
wider
range
of
tasks
performed
by
the
co­
pilot.
However,
the
co­
pilots
exposures
See
response
to
comment
#
41
have
been
reduced
over
time
by
the
use
of
better
injection
methodologies,

improved
barrier
films,
and
modifications
in
the
engine
fans
of
the
tractors.
As
in
the
case
of
the
tractor
driver
and
applicator,
current
levels
are
expected
to
be
lower
than
the
levels
in
the
studies
from
the
early
1990s
since
application
rates
have
declined
over
the
last
10
years.

°
Shovelman
Exposures
to
these
workers
are
controlled
by
improved
injection
techniques
and
by
use
of
high
barrier
films.
Current
levels
are
expected
to
be
lower
than
the
levels
in
the
studies
from
the
early
1
990s
since
application
rates
have
declined
over
the
last
10
years.

°
Tarp
Cutter
and
Tarp
Remover
Tarp
cutters
and
tarp
removers
have
a
potential
for
exposure
that
is
potentially
increased
by
the
use
of
high
barrier
films
(
tmpping
more
methyl
bromide).

However
as
the
study
listed
as
Field
20
indicates,
these
exposures
can
be
greatly
minimized
if
the
cutting
of
the
tarps
is
performed
on
one
day
and
the
tarps
are
removed
on
a
subsequent
day.
Cutting
the
tarps
allows
the
residual
methyl
bromide
to
dissipate
prior
to
removal
of
the
tarps.
Current
levels
are
expected
to
be
lower
than
the
levels
in
the
studies
from
the
early
1990s
since
application
rates
have
declined
over
the
last
10
years.

°
Second
Tractor
Driver
MBIP
recommends
that
EPA
drop
this
classification
for
the
following
reasons.

First,
the
Pipe
Layer
and
Pipe
Tractor
workers
are
listed
under
the
"
Irrigation
Workers"
job
category
and
should
not
be
considered
under
this
category.
Second,

the
classification
includes
measurements
at
are
no
longer
common
practice.
The
reference
to
"
Tarp
Layer"
occurs
in
the
study
listed
as
"
Field
3".
In
this
study,
a
second
tractor
applied
the
tarp
following
the
tractor
that
injected
the
Methyl
Bromide.
This
practice
is
not
common
today.
The
reference
to
"
Cultipacker
Driver"
occurs
in
the
study
listed
as
"
Field
22".
In
this
study,
a
second
tractor
pulls
a
cultipacker
that
closes
the
soil
furrows
following
injection
of
Methyl
Bromide.
Again
this
practice
is
not
common
today.
Under
current
practices,
a
single
tractor
pulls
equipment
that
both
injects
the
Methyl
Bromide,
and
lays
the
tarp
in
one
operation.

Third,
the
remaining
workers,
"
Drip
Tape",
and
"
Plastic
Truck
Driver"
represent
two
very
different
jobs.
The
"
Drip
Tape
Layer"
is
the
driver
of
a
tractor
lays
a
drip
line,
or
drip
tape,
in
the
field
prior
to
the
injection
of
the
Methyl
Bromide
and
tarp
placement.
The
"
Plastic
Truck
Driver"
delivers
the
rolls
of
plastic
tarp
to
the
tractor
but
does
not
enter
the
treated
field.
The
differences
between
these
two
tasks
makes
the
grouping
useless
in
characterizing
occupational
exposures.

Fourth,
there
is
only
a
single
measurement
for
each
of
the
categories.
This
is
too
limited
a
data
set
to
reach
any
conclusions.

Finally,
the
various
jobs
occur
at
locations
that
are
farther
from
the
soil
injection
process
than
the
locations
of
the
First
Tractor
Driver,
Co­
pilot,
and
Shovelman
and
are
likely
to
have
exposures
that
are
lower
than
those
jobs.
Mitigations
that
protect
these
three
exposure
categories
will
also
protect
the
more
distant
workers.

°
Irrigation
Worker
The
irrigation
workers
are
the
pipe
layers
and
the
pipe
tractor
drivers.
Data
on
these
workers
comes
from
two
studies
of
raised
bed
tarped
applications
(
Fields
4
and
22).
These
workers
were
involved
in
placing
water
on
top
of
the
tarp
as
a
means
of
forcing
the
tarp
to
remain
on
the
ground.
In
these
instances,
the
tarp
remains
on
the
field
as
mulch.
This
practice
is
not
commonly
performed
today.

Because
of
this
change
in
practices
there
is
no
need
to
evaluate
this
job
classification.
71
127
Overall
Conclusions
on
Occupation
Exposures
for
Pre­
plant
Soil
Fumigation
In
short,
the
available
data
on
methyl
bromide
exposures
resulting
from
soil
fumigation
indicate
that
the
current
exposures
are
significantly
lower
than
the
estimates
given
in
the
PRA.
The
MBIP
urges
EPA
to
take
the
foregoing
comments
into
account
and
reconsider
its
conclusions
on
potential
occupational
risks
from
soil
applications.
See
response
to
comment
#
41
72
127
Acute
exposure
The
Agency
identified
a
potential
acute
risk
concern
for
avian
species.
Exposure
modeling
was
performed
using
the
ISCST3
model
and
risk
assessments
performed.
Under
these
conditions,
the
Agency
showed
that
the
acute
inhalation
risks
to
birds
do
not
exceed
even
the
lowest
of
the
LOCs,
including
endangered
species.
The
avian
acute
RQ
was
0.03.
Based
on
the
conservative
exposure
concentrations
generated
by
the
ISCST3
model,
conducting
acute
inhalation
testing
in
avian
species
is
considered
a
waste
of
animal
resources
and
the
study
requirement
should
be
waived.
The
avian
inhalation
risk
assessment
is
based
on
extrapolation
from
mammals.
The
extrapolation
uses
acute
oral
data
for
mammals
and
birds,
mammal
inhalation
data,
and
a
mammal
to
bird
conversion
factor.
Acute
avian
inhalation
data
will
reduce
any
uncertainty
associated
with
this
extrapolation.

73
127
Chronic
exposure
In
its
risk
assessment,
the
Agency
indicated
that
a
chronic
avian
inhalation
study
"
will
enable
the
Agency
to
address
chronic
exposure
to
birds".
The
Agency
concern
relates
to
the
potential
for
wild
birds
to
be
exposed
repeatedly
as
a
result
of
treatment
of
multiple
fields
over
multiple
days
in
the
birds'
home
range
or
territory.

Chronic
(
long­
term)
exposure
testing
of
avian
species
is
covered
by
guideline
OPPTS
850.2300,
Avian
Reproduction
study.
This
data
requirement
is
for
assessing
dietary
risk.
The
study
design
entails
initial
exposure
of
adult
male
and
females
birds
for
a
period
of
10
weeks.
During
that
period,
the
light
cycle
is
gradually
increased
(
photostimulation)
to
induce
egg
laying.
Any
significant
stress
or
disruption
to
the
birds
would
have
significant
impact
on
the
study.
For
inhalation
exposure,
the
birds
would
need
to
be
moved
each
day
to
confined
cages
within
the
inhalation
chamber.
Such
movement
and
confinement
alone
would
significantly
stress
the
birds
leading
to
deficits
in
body
weight,
food
consumption
and
survival.
Addition
of
chemical
exposure
would
most
likely
add
to
the
stress
on
the
birds.
Stress
also
may
lead
to
production
of
infertile
eggs.

The
second
phase
of
the
study
is
the
egg
laying
phase
in
which
eggs
are
collected
for
at
least
10
weeks,
incubated
and
hatched.
OPPTS
850.2300
specifically
states
that
"
taking
of
body
weights
during
egg
laying
is
discouraged
because
of
possible
adverse
effects
on
egg
production."
During
the
egg
laying
phase,
the
physical
handling
and
placement
of
the
birds
into
the
inhalation
chambers
alone
would
be
expected
to
lead
to
ruptured
yolks
and
broken
eggs
within
the
female
reproductive
tract
and
ultimately
lead
to
death
of
those
birds.

Clearly,
long­
term
exposure
of
avian
species
is
not
a
practical
consideration.
No
meaningful
results
would
be
achieved
given
the
way
the
study
is
required
to
be
designed,
and
there
would
be
no
scientific
benefit
to
running
it.
In
short,
it
would
amount
to
a
waste
of
test
animals
and
resources.
As
an
aside,
it
also
is
evident
that
there
are
no
laboratories
equipped
to
conduct
long­
term
avian
inhalation
studies
yet
alone
attempt
a
reproductive
study
by
this
route
of
exposure.
EFED
envisions
an
inhalation
study
longer
than
the
typical
(
e.
g.,
mammal)
acute
study
(
4
hours),
not
a
full
reproduction
study.
74
(
EFED)
127
Terrestrial
Risks
­­
Risks
to
Non­
Target
Terrestrial
Plants
 
Page
28
The
Agency
has
requested
that
terrestrial
plant
guideline
toxicity
data
are
needed
to
evaluate
risks
to
non­
target
plants
off
site.
The
terrestrial
plant
guideline
studies
are
designed
to
evaluate
the
effect
of
pesticide
products
on
seedling
emergence
(
850.4100)
and
vegetative
vigor
(
850.4150).
The
general
concern
is
related
to
either
overspray
or
spray
drift
of
pesticide
products
from
the
treated
area.

Methyl
bromide
is
directly
injected/
applied
to
field
areas
that
are
tarped.
The
treated
area
is
defined
so
that
off
site
applications
will
not
occur.

The
seedling
emergence
study
is
not
appropriate
for
methyl
bromide
because
the
method
of
application
is
such
that
overspray
and/
or
drift
will
not
occur
in
nontarget
areas.

The
vegetative
vigor
study
is
designed
to
evaluate
phytotoxicity
from
direct
spraying
on
nontarget
plants.
Generally
several
concentrations
are
used
spanning
the
field
application
rate
and
level
above
and
below
that
rate.
Methyl
bromide
is
not
directly
applied
to
plants.
There
is
no
evidence
that
methyl
bromide
vapors
would
plate
on
plant
surfaces
in
areas
outside
of
the
treated
area.
Thus,
this
study
is
not
appropriate
to
methyl
bromide
and
its
requirement
must
be
reconsidered.
Seedling
emergence
and
vegetative
vigor
study
protocols
have
been
submitted
by
another
registrant
for
another
fumigant.
The
goal
is
to
evaluate
the
toxicity
of
the
volatilized
vapors
to
plants.
Protocols
for
methyl
bromide
should
also
be
submitted.

75
(
EFED)
127
Aquatic
Risks
­­
Page
29
On
page
29
of
the
"
Overview
of
the
Preliminary
Methyl
Bromide
Risk
Assessment
(
July
13,
2005)"
it
is
stated
that:
Acute
and
chronic
LOCs
for
freshwater
fish
are
not
exceeded,
but
the
analysis
is
based
on
supplemental
data
(
acute)
and
on
open
literature
(
chronic)
only.
Core
acute
and
chronic
fish
data
on
methyl
bromide
are
needed
to
more
fully
evaluate
risk
to
fish.

LOCs
for
aquatic
plants
are
not
exceeded
based
on
available
data,
but
additional
toxicity
data
are
needed
to
complete
this
assessment.

Although
these
statements
appear
in
the
`
Revised
Draft
Methyl
Bromide
Environmental
Fate
and
Ecological
Risk
Assessment
following
the
review
of
30­

Day
Error
Correction
Comments
(
June
6,
2005)',
it
is
important
to
note
that
the
document
also
states
in
the
Executive
Summary
age
4
of
92)
that:

Toxicity
databases
for
acute
exposure
of
mammals,
birds,
fish,
aquatic
invertebrates
and
algae
and
chronic
exposure
of
mammals
and
fish
are
adequate
to
estimate
risk
using
a
RQ
approach."

The
MBIP
concurs
with
the
conclusion
that
the
current
databases
above
are
adequate.
Conducting
further
testing
would
not
be
fruitful
or
relevant
to
potential
environmental
exposures
related
to
the
actual
uses
of
methyl
bromide.

The
Environmental
Fate
and
Ecological
Risk
Assessment
states
that
"
the
Henry's
law
constant
of
744
Pa­
m3/
mol
suggests
that
it
will
be
volatized
from
surface
water,
thus
chronic
exposure
to
methyl
bromide
is
expected
to
be
low."
Because
of
the
volatility
of
methyl
bromide
from
water,
artificial
test
systems
were
developed
to
permit
evaluation
of
short­
term
exposures
of
aquatic
organisms
to
methyl
bromide.

Aquatic
acute
studies
with
rainbow
trout
and
daphnids
were
conducted
by
the
MBTP
and
submitted
to
EPA
in
fulfillment
of
reregistration
requirements.

Because
of
the
rapid
volatilization
of
methyl
bromide
from
water,
these
studies
were
conducted
in
exposure
chambers
with
minimal
to
no
headspace
and
sealed
to
prevent
loss
from
the
test
chambers.
Rainbow
trout
were
exposed
in
4L
serum
1)
Supplemental
studies
may
be
used
for
risk
quotients,

but
this
does
not
mean
that
Acceptable
(
formerly
Core)

studies
are
not
still
needed.
Better
quality
data
can
improve
the
quality
of
the
risk
assessment.

2)
It
is
EFED's
understanding
that
chronic
flowthrough
studies
with
measured
concentrations
are
possible
and
appropriate.
bottles
containing
approximately
4
liters
of
test
solution
(
MRID
43066701).
The
bottles
were
sealed
with
22
mm
Teflon
faced
septa.
Methyl
bromide
gas
was
directly
introduced
into
the
exposure
chambers
by
piercing
the
septum
and
injecting
the
methyl
bromide
gas
directly
into
the
water
column.
In
order
to
further
maintain
methyl
bromide
concentrations,
the
studies
were
conducted
under
static
conditions
since
it
was
anticipated
that
the
methyl
bromide
would
rapidly
dissipate
from
the
water
column.
As
per
guideline,
the
water
temperature
in
this
study
was
maintained
in
the
range
of
10.9
to
11.8
°
C.

Table
7
below
summarizes
the
methyl
bromide
concentrations
in
water
seen
under
the
artificial
exposure
conditions
described
above.
The
results
show
that
it
was
possible
to
maintain
methyl
bromide
concentrations
of
approximately
I
to
2
mgfL
over
the
4­
day
exposure
period.
Despite
the
measures
to
prevent
methyl
bromide
loss,
methyl
bromide
concentrations
declined
by
10%
to
20%
over
the
4­
day
period
at
higher
concentrations
(
2
to
9
mgIL).
The
96­
hour
LC5O
under
these
conditions
was
3.9
mg/
L
classifying
methyl
bromide
as
slightly
to
moderately
toxic
to
fish.

Similar
artificial
conditions
were
used
to
exposure
cladocerans
(
Daphnia
magna)

to
methyl
bromide.
The
daphnids
were
exposed
in
1
00­
ml
serum
bottles
containing
approximately
125
ml
of
test
solution
with
no
headspace.
The
bottles
were
sealed
with
20
mm
Teflon
faced
septa
to
prevent
volatilization
of
methyl
bromide.
The
water
temperature
was
maintained
at
20
±
1
°
C.
The
methyl
bromide
concentrations
seen
in
the
daphnid
study
are
summarized
in
Table
8
as
follows:

The
analytical
results
demonstrate
that
stable
methyl
bromide
concentrations
were
maintained
during
the
48­
hour
exposure
period.
The
apparent
differences
in
the
stability
of
the
high
test
concentrations
between
the
daphnid
and
trout
studies
may
be
attributed
to
the
shorter
duration
of
the
study,
the
smaller
exposure
vessels
and
the
"
overfilling"
of
the
exposure
vessels
with
water
to
assure
no
headspace.

Collectively,
the
analytical
results
show
that
stable
concentrations
of
methyl
bromide
in
water
can
be
maintained
under
static
conditions
with
no
headspace
for
48
hours.

The
standard
methodologies
for
longer­
term
aquatic
studies
require
flow­
through
systems
to
assure
that
both
test
substance
concentration
and
water
quality
conditions
are
maintained.
This
testing
methodology
would
not
be
practical
for
methyl
bromide
as
it
would
be
logistically
difficult,
if
not
impossible
to
conduct
long­
term
studies
under
flow­
through
conditions
in
a
completely
sealed
system,

i.
e.,
no
headspace
in
the
exposure
vessel
into
which
methyl
bromide
would
dissipate
or
closed
flow
cells
without
headspace.
Further,
water
turbulence
in
such
a
system
would
drive
methyl
bromide
from
the
water.
Thus,
it
would
not
be
possible
to
consistently
maintain
methyl
bromide
concentrations.

Neither
is
it
practical
to
conduct
the
longer­
term
studies
under
static
conditions.
In
the
rainbow
trout
acute
study,
loss
of
methyl
bromide
occurred
over
the
4­
day
period
even
in
a
virtually
sealed
system.
More
importantly,
a
34%
decrease
in
dissolved
oxygen
concentration
occurred,
a
condition
that
would
be
detrimental
to
the
health
of
the
aquatic
organisms.

In
any
event,
the
test
methodologies
described
above
clearly
do
not
simulate
the
potential
exposure
of
aquatic
organism
and
aquatic
plants
to
methyl
bromide.
Such
exposures
could
be
simulated
by
direct
injection
of
methyl
bromide
into
the
water
column
however,
methyl
bromide
would
rapidly
volatilize
from
the
water
and
stable
concentrations
could
not
be
maintained.
These
types
of
studies
would
need
to
be
conducted
in
chambers
to
contain
methyl
bromide
vapors
to
avoid
occupational
exposure
to
technical
staff.
It
is
not
practical
to
conduct
the
aquatic
toxicity
studies
in
enclosed
systems
since
a
number
of
processes
in
long
term
aquatic
studies
would
require
opening
of
the
test
vessels
and
losses
of
methyl
bromide.

The
trigger
for
the
acute
and
chronic
aquatic
organism
and
the
acute
aquatic
plant
toxicity
studies
is
related
to
the
potential
for
methyl
bromide
to
either
be
directly
added
to
water
or
to
translocate
to
water
bodies.
The
volatility
of
the
product
argues
against
translocation
and
methyl
bromide
is
not
used
in
a
manner
leading
to
direct
application
to
water.
Further,
the
Henry's
law
constant
supports
a
conclusion
that
methyl
bromide
would
not
remain
in
water
even
if
trans
location
occurred.

As
recognized
by
the
Agency
scientists,
the
toxicity
databases
for
acute
exposure
of
mammals,
birds,
fish,
aquatic
invertebrates
and
algae
and
chronic
exposure
of
mammals
and
fish
are
adequate
and
have
permitted
the
estimation
of
risks
using
a
RQ
approach.

In
consideration
of
the
ability
of
the
Agency
to
perform
risk
assessment
coupled
with
the
chemical
nature
of
methyl
bromide,
the
very
low
potential
for
exposure
to
aquatic
organism
and
the
impracticality
of
testing
methyl
bromide
in
standard
aquatic
toxicity
studies,
the
MBIP
requests
the
Agency
reconsider
the
requirements
for
testing
in
aquatic
organism
and
plants.

76
(
EFED)
127
Aquatic
Organisms
 
Bromide
Toxicity
Field
applications
of
methyl
bromide
are
not
expected
to
increase
levels
of
free
bromide
that
would
translocate
to
water
bodies.
Flux
studies
have
demonstrated
that
the
vast
majority
of
methyl
bromide
volatilizes
from
the
soil.
The
MBIP
requests
that
the
Agency
reconsider
the
requirements
for
the
evaluation
of
bromide
toxicity
on
aquatic
organisms.
References
cited
in
the
Ecological
Risk
Assessment
of
Methyl
Bromide
document
suggest
that
a
significant
portion
of
applied
methyl
bromide
can
degrade
in
soils
(
page
17)
and
consequently
bromide
ions
can
potentially
accumulate
in
soils
(
Page
36).
Thus,

accumulated
bromide
ions
in
soil
can
potentially
transport
to
nearest
water
bodies
via
runoff
events.
As
indicated
in
the
7/
8/
04
memorandum,
"
current
aquatic
modeling
indicates
the
potential
for
chronic
exposure
to
the
bromide
ion,
very
near
the
available
open
literature
fish
NOAEC.
This
study
will
enable
a
complete
chronic
risk
assessment
for
freshwater
fish,

with
reduced
uncertainty".

77
128
°
"
Safe
use"
of
these
fumigants
cannot
be
ensured,
as
indicated
by
the
number
and
severity
of
poisoning
incidents
for
different
fumigants.
We
highlight
a
number
of
these
poisonings
and
their
effects
on
the
lives
of
individuals
and
strongly
urge
EPA
to
phase
out
the
use
of
these
chemicals.
The
Agency's
risk
assessment
process
will
include
a
thorough
analysis
of
incident
reports.

78
°
The
FQPA's
"
reasonable
certainty
of
no
harm"
standard
is
not
consistently
employed
in
risk
assessment,
nor
is
a
consideration
of
all
routes
of
exposure
to
ensure
adults
and
children
are
protected.
See
response
to
comment
#
36
&
42
79
°
External
costs
of
fumigant
use
are
rarely
considered
including
costs
associated
with
ill
health,
disabilities,
and
environmental
damage
caused
by
fumigant
The
Agency
agrees
that
alternatives
along
with
other
risk
mitigation
options
(
e.
g.
emission
reduction
exposure.

°
Real
world
conditions
warrant
assessment
of
cumulative
risks
of
exposure
to
multiple
fumigants
to
ensure
protection
of
the
most
fumigant­
affected
populations,

i.
e.
farm
workers
and
nearby
residents.

°
Non­
chemical
alternatives
to
fumigants
exist,
are
documented,
and
warrant
greater
emphasis
and
evaluation.
EPA
plays
a
key
role
in
calling
out
these
alternatives
to
USDA
to
develop
methods
of
support
for
farmers
to
ensure
a
just
transition
to
alternatives.

°
Affected
communities
must
be
consulted
at
all
stages
of
the
fumigant
cluster
assessment
process
methods)
must
be
considered
in
combination
with
a
cost/
benefits
analysis.
Furthermore,
along
with
the
Phase
5
revised
risk
assessment,
the
Agency
seeks
public
comment
on
Risk
Mitigation
Options
for
commodity
uses
The
Agency
is
working
with
closely
with
USDA's
Agricultural
Research
Service
to
fund
research
on
methyl
bromide
alternatives.

80
128
Although
we
do
not
object
to
the
use
of
pharmacokinetic
data
to
refine
the
fumigant
risk
assessments,
we
do
believe
that
the
scientific
support
and
information
provided
in
US
EPA's
calculation
of
human
equivalency
concentrations
(
HEC)
in
each
risk
assessment
is
inadequate.
Another
flaw
in
the
US
EPA's
derivation
of
HECs
is
that
test
animal
exposures
to
fumigants
do
not
match
typical
human
exposures.
We
offer
specific
recommendations
in
our
comments
to
make
the
derivation
of
HECs
for
inhalation
exposures
more
transparent
and
accurate.
See
response
to
comment
#
37.
The
Agency
also
notes
that
part
of
the
dosimetric
adjustment
conducted
in
this
risk
assessment
to
derive
HECs
includes
an
adjustment
for
duration
of
exposure.
Hence,
the
different
HECs
calculated
for
occupational
vs.
non­
occupational
exposures.
For
occupational
exposures,
the
Agency
assumes
that
individuals
may
be
exposed
during
the
course
of
an
average
workweek
(
8
hrs/
day
and
5
days/
week).
In
the
case
of
non­
occupational
exposures
(
i.
e.,
bystanders),
it
is
assumed
that
exposure
may
occur
24
hours/
day
for
7
days/
week.
By
conducting
these
adjustments
as
part
of
the
HEC
derivation,
the
Agency
believes
that
the
differences
between
animals
and
humans
exposure
to
the
fumigant
have
been
accounted
for
in
the
risk
assessment.

81
128
In
general,
the
discussion
and
justification
for
the
use
of
uncertainty
factors
in
the
risk
assessment
is
difficult
to
follow,
and
the
rationale
for
selecting
uncertainty
factors
unclear;
it
appears
to
us
that
US
EPA's
decisions
were
subjective
and
arbitrary.
We
recommend
that
US
EPA
adopt
the
more
widely
used
default
methodology,
as
explained
in
our
comments,
and
consider
additional
uncertainty
factor
applications
in
specific
cases.
See
response
to
comment
#
37
82
128
In
general,
the
sections
referring
to
aggregate
risk
in
the
risk
assessments
are
too
superficial
to
fully
understand
what
US
EPA
is
attempting
to
do.
We
recommend
that
US
EPA
revise
the
risk
assessment
documents
to
include
a
full
quantitative
analysis
for
the
combination
of
the
three
major
exposure
routes
for
all
exposure
sources
for
each
chemical
fumigant.
See
response
to
comment
#
36
&
42
83
128
There
is
no
attempt
by
US
EPA
to
consider
human
exposures
to
mixtures
of
fumigants,
or
sequential
exposures
to
the
fumigants
as
they
are
applied
in
practice.

We
provide
specific
examples
in
our
comments
on
how
the
risk
assessments
could
be
revised
to
include
cumulative
risk
assessment.
Section
8.0
of
the
risk
assessment
characterizes
the
Agency
position
on
cumulative
exposure
related
to
methyl
bromide
uses.

84
128
In
conducting
cumulative
risk
assessments,
we
urge
US
EPA
to
define
the
methodology
in
broader
terms
than
simply
summing
the
risks
for
comparable
toxicity
endpoints
for
chemicals
with
the
same
mechanism
of
action.
Detrimental
effects
to
the
body
caused
by
a
chemical
might
make
an
individual
more
vulnerable
to
the
toxicity
of
another
chemical,
which
acts
by
a
different
mechanism.
In
the
absence
of
data
to
substantiate
taking
no
action,
an
additional
See
response
to
comment
#
83
uncertainty
factor
is
indicated.

85
128
Bystander
Exposure
Assessment
A
review
of
major
poisonings
shows
that
common
features
are
low
wind
speeds
and
other
conditions
necessary
for
high
atmospheric
stability.

Low
wind
speeds
occur
frequently,
during
at
least
10%
of
the
hours
annually,
and
up
to
30%
of
the
hours
depending
on
the
cutoff
defining
low
wind
speeds
and
the
weather
stations
used
for
the
estimates.

The
ISCST3
model
and
methodology
used
by
EPA
systematically
underestimates
air
concentrations
during
calm
and
near­
calm
wind
conditions
by
treating
concentrations
calculated
for
these
conditions
as
missing.

The
AERMOD
model
which
can
provide
estimates
under
these
circumstances
is
available
and
should
be
used
to
compute
realistic
fumigant
air
concentrations.

Use
of
the
AERMOD
model
instead
of
the
ISCST3
model
in
this
circumstance
is
in
compliance
with
EPA
regulatory
guidelines.
In
the
revised
assessment
for
commodities,
the
PERFUM
model
is
now
being
used
with
ISCST3.
The
Agency
is
in
process
of
accounting
for
low
wind
speeds
in
modeling
estimates
as
well
as
the
feasibility
and
benefit
of
using
AERMOD
in
place
of
ISCST3.

The
first
indication
related
to
AERMOD
is
that
it
will
not
provide
significantly
different
results
since
the
major
modifications
have
been
to
the
algorithms
that
address
buoyant
plumes
(
e.
g.,
heated
stack
emissions)

and
not
non­
buoyant
plumes
(
e.
g.,
methyl
bromide
which
is
not
heated
and
more
dense
that
air).

86
128
There
is
insufficient
detail
to
follow
or
comment
on
the
indirect
back­
calculation
method
for
determining
flux.
Detail
lacking
includes
the
field
monitoring
studies
used,
the
criteria
for
combining
or
eliminating
study
results,
and
the
comparison
of
study
results.
The
flux
calculation
and
hence
the
exposure
modeling
calculation
are
therefore
not
transparent.
See
response
to
comment
#
41
87
128
The
model
(
including
its
calibration
through
the
back­
calculation
of
flux
values)

was
not
corroborated
with
known
major
poisoning
incidents.
Demonstrating
that
the
calibrated
model
correctly
predicts
past
incidents
would
increase
confidence
that
the
model
results
will
correctly
validate
risk
mitigation
strategies
and
prevent
future
incidents.
See
response
to
comment
#
41
88
Dismissal
of
ambient
chronic
and
sub­
chronic
exposure
is
premature
for
multiple
reasons
including
the
fact
that
some
of
the
existing
studies
did
indicate
that
levels
of
concern
were
exceeded,
the
sensitivity
of
the
result
to
HEC
and
MOE
values,

and
trends
of
increasing
use
which
render
old
air
monitoring
studies
obsolete
The
Agency
has
calculated
chronic
and
sub­
chronic
risks
based
on
available
ambient
data.

89
128
Assessments
for
multiple
(
successive,
geographically
neighboring)
applications
have
not
been
included
and
will
increase
the
exposure
estimates
when
they
are.
The
Agency
aggress
that
this
is
possible.

90
128
Occupational
Exposure
Assessment
These
risk
assessments
show
that
a
majority
of
occupational
exposures
to
metam
sodium,
dazomet
and
methyl
bromide
are
much
too
high,
with
the
Agency's
estimates
of
exposure
for
many
jobs
having
little
or
no
safety
margin.

Our
concerns
are
heightened
because
these
risk
assessments
are
based
on
many
assumptions
which
underestimate
occupational
exposures.
Specifically
we
conclude
that
the
length
of
workday,
number
of
days
worked
per
year
and
fumigant
exposure
levels
are
underestimated.
In
contrast,
respiratory
protection
factors
are
overestimated.
The
Agency
is
committed
to
refining
risk
estimates
based
on
information
from
all
stakeholders.
The
Agency
believes
that
the
revised
risk
assessment
adequately
characterizes
the
conservativeness
and
uncertainties.

91
128
EPA
Must
Seriously
Consider
Existing
Viable
Alternatives
The
substantial
evidence
of
the
hazards
fumigants
pose
to
workers
and
bystanders
indicates
that
EPA
cannot
be
assured
that
there
is
a
reasonable
certainty
of
no
harm
from
registration
and
use
of
these
chemicals.
For
workers
especially,
it
is
clear
that
the
extreme
risks
outweigh
the
limited
benefits.
The
Agency
agrees
that
alternatives
along
with
other
risk
mitigation
options
(
e.
g.
emission
reduction
methods)
must
be
considered
in
combination
with
a
cost/
benefits
analysis.
Furthermore,
along
with
the
Phase
5
revised
risk
assessment,
the
Agency
seeks
The
fumigants
considered
in
this
cluster
assessment
have
viable
non­
toxic
alternatives
that
are
being
used
successfully
for
fumigant­
intensive
crops
in
many
climatic
and
ecological
zones.
These
fumigants
continue
to
be
responsible
for
mass
poisonings
as
well
as
chronic
adverse
health
effects.
We
urge
EPA
to
invest
more
resources
in
alternatives
assessment
work
with
USDA
to
help
farmers
transition
away
from
fumigants
as
a
soil
pest
control
strategy
public
comment
on
Risk
Mitigation
Options
for
commodity
uses
The
Agency
is
working
with
closely
with
USDA's
Agricultural
Research
Service
to
fund
research
on
methyl
bromide
alternatives.

92
129
 
one
problem
with
the
current
modeling
is
that
it
does
not
take
the
seasonality
of
applications
by
crop
into
account
.
For
example
more
than
75%
of
the
pre­
plant
MeBr
applications
in
almonds
occur
Nov­
Jan
.

In
2002
5%,
in
2003
9%,
and
in
2004
13%
of
the
applications
took
place
between
May
1
and
October
31,
and
most
of
those
were
in
October.
Given
that
rain
fall,
air
temperature
and
winds
are
very
different
during
the
winter
months
from
the
summer
months
in
the
Central
Valley,
accounting
for
seasonality
of
applications
by
crop
is
critical
to
understand
the
actual
bystander
exposure
risks
posed.
See
response
to
comment
#
41
93
129
Nor
does
the
model
account
for
the
days
when
methyl
bromide
cannot
be
applied
due
to
,
the
weather
conditions.
Any
MeBr
application
requires
a
permit
from
the
county
ag.
commissioner's
office
as
well
as
a
24
h
pre­
notification
of
the
planned
application.
If
there
are
inversion
weather
conditions
the
ag
.
commissioner
will
not
allow
the
fumigation.
Similarly
if
the
soil
is
too
moist,
which
leads
to
poor
penetration,
the
ag.
commissioners
will
not
permit
the
application
.
Thus,
there
is
not
an
equal
probability
at
methyl
bromide
will
be
applied
any
of
the
365
days
of
the
year
by
almond
growers
as
currently
assumed
in
the
model
.
It
is
unclear
whether
EPA
made
any
effort
to
exclude
weather
conditions
where
MeBr
would
not
be
applied
in
their
calculations
and
thus
in
the
data
presented
as
bystander
exposure.
See
response
to
comment
#
41
94
129
It
was
impossible
to
understand
the
assumptions
EPA
used
in
the
worker
exposure
risk
assessment
for
methyl
bromide
(
the
referred
to
appendices
were
completely
unintelligible
and/
or
illegible)
.
A
updated
legible
version
of
the
appendices
has
been
added
to
the
docket.

95
129
The
pre­
plant
applications
of
methyl
bromide
in
almonds
are
exclusively
done
by
custom
applications
as
required
by
the
State
of
California
.
Thus,
it
is
likely
that
a
single
applicator
will
be
exposed
to
methyl
bromide
several
days
in
a
row
.

However,
the
state
has
also
recently
introduced
limitations
to
the
number
of
hours
and
acres
that
a
single
applicator
may
treat
in
a
day
to
reduce
worker
exposure.

The
typical
application
will
involve
the
applicator,
who
also
does
the
mixing
and
loading,
along
with
a
supervisor.

The
presence
of
a
second
trained
person
is
required
by
California
for
monitoring.

Most
commonly
a
third
person
will
be
disking
the
soil
as
a
seal
several
rows
behind
the
applicator.
Tarps
are
not
used
in
the
almond
industry.
EPA
does
not
discuss
the
single
tree­
hole
treatment
.
These
applications
are
typically
done
by
the
growers
or
employees
.
The
state
requires
special
training
of
anyone
working
with
methyl
bromide
as
well
as
the
presence
of
two
persons
during
the
application
.
The
methyl
bromide
is
injected
into
the
prepped
hole
(
loose
soil)
ideally
at
2­
3
ft
depth
using
a
injector
attached
to
a
pressurized
canister.
As
mentioned
above
the
typical
rate
is
1
lb/
hole.
This
is
method
is
most
commonly
used
to
treat
replants
of
young
trees
in
an
existing
orchard
that
have
died
due
to
soil
pest
issues.
See
response
to
comment
#
41
96
129
EPA
discusses
the
bystander
exposure
both
in
terms
of
the
maximum
buffer
distances
from
the
field
where
the
MOE
is
achieved
as
well
as
whole
field
buffer
distances.
Unfortunately
it
is
still
very
difficult
to
understand
what
the
whole
field
buffer
distances
mean
both
mathematically
as
well
as
in
reality.
If
EPA
would
like
to
use
whole
field
buffer
calculations
in
the
risk
assessments
and
risk
mitigation,
then
a
greater
effort
is
needed
to
educate
readers
on
what
the
whole
field
buffers
represent.
See
response
to
comment
#
41
Page
42
UNITED
STATES
ENVIRONMENTAL
PROTECTION
AGENCY
WASHINGTON,
D.
C.
20460
OFFICE
OF
PREVENTION,
PESTICIDES
AND
TOXIC
SUBSTANCES
MEMORANDUM
Subject:
Response
to
Comments
­­
Methyl
Bromide's
Uses
in
Enclosures,
Chambers,
Structural
Food
Processing/
Storage
Facilities
(
Docket
Number
EPA­
HQ­
OPP­
2005­
0123).

From:
Jonathan
Becker,
Ph.
D.,
Senior
Science
Advisor
William
Chism,
Ph.
D.,
Senior
Agronomist
Biological
Analysis
Branch
Biological
and
Economic
Analysis
Division
(
7503C)

To:
Steven
Weiss,
Chemical
Review
Manager
Special
Review
Branch
Special
Review
and
Reregistration
Division
(
7508C)

Product
Review
Panel
Date:
March
15,
2006
The
Environmental
Protection
Agency
(
EPA)
has
received
a
number
of
comments
related
to
the
risk
assessment
for
methyl
bromide.
Comments
submitted
to
the
docket
(
EPA­
HQ­
OPP­
2005­
0123)
related
to
the
commodity
or
structural
uses
of
methyl
bromide
are
discussed
generally
below.
Comments
related
to
the
soil
uses
of
this
chemical
will
be
addressed
at
a
later
date.

Comments
on
the
commodity
and
structural
uses
of
methyl
bromide
can
be
grouped
into
three
subject
areas:
the
importance
of
methyl
bromide
to
commodity
fumigation,
use
practices
and
application
rates
used
in
the
risk
assessment,
and
limitations
of
methyl
bromide
alternatives.

Importance
of
methyl
bromide
in
commodity
and
structural
fumigation
Comments:
Many
of
the
comments
emphasized
the
importance
of
methyl
bromide
related
to
the
elimination
of
unwanted
pests
(
phytosanitary
and
quarantine
purposes).
Fumigation
with
methyl
bromide
is
required
for
export
to
certain
countries
and
is
required
by
USDA/
APHIS
for
importation
of
some
commodities
into
the
United
States.
Further,
because
the
use
of
methyl
bromide
allows
rapid
fumigation
and
ventilation
of
commodities,
certain
market
windows
can
be
met
only
with
the
use
of
this
fumigant.

EPA
Response:
EPA
recognizes
the
benefits
of
methyl
bromide
in
commodity
and
structural
fumigation.
Since
the
initiation
of
the
Methyl
Bromide
Critical
Use
Exemption
process
under
the
Page
43
Montreal
Protocol,
the
Biological
and
Economic
Analysis
Division
of
the
Office
of
Pesticide
Programs,
in
conjunction
with
the
Office
of
Air
and
Radiation,
has
developed
the
annual
United
States
nomination
for
critical
use
exemptions
from
the
phaseout
of
methyl
bromide.
These
technical
documents
discuss
in
detail
the
benefits
of
methyl
bromide.
The
most
recent
documents
for
commodities
and
structures
may
be
located
at:
http://
www.
epa.
gov/
ozone/
mbr/
CUN2008/
CUN2008_
Commodities.
pdf
and
http://
www.
epa.
gov/
ozone/
mbr/
CUN2008/
CUN2008_
PostHarvest.
pdf
.

Use
practices
and
application
rates
used
in
the
risk
assessment
Comments:
Several
comments
indicated
that
the
risk
assessment
did
not
reflect
their
experience
using
methyl
bromide
in
terms
of
general
use
practices
and
application
rates.

EPA
Response:
Many
of
these
comments
have
been
incorporated
in
the
revised
risk
assessment.
Please
refer
to
the
risk
assessment
for
the
commodity
uses
of
methyl
bromide
in
"
Methyl
Bromide:
Revised
Health
Effects
Division
(
HED)
Human
Health
Risk
Assessment
for
Phase
5"
(
Jeff
Dawson,
March
10,
2006).
This
document
is
included
the
Methyl
Bromide
Docket
(
EPAHQ
OPP­
2005­
0123).

Limitations
of
methyl
bromide
alternatives
Comments:
Several
comments
indicate
that
some
alternatives
damage
the
commodity
(
e.
g.,
heat),
are
not
accepted
by
the
market
(
e.
g.,
irradiation),
are
restricted
by
regulation
(
e.
g.,
township
caps
for
Telone),
or
have
limited
efficacy
against
key
pests.

EPA
Response:
EPA
acknowledges
the
limitations
of
some
alternatives.
Any
proposed
change
in
the
use
pattern
of
methyl
bromide
will
be
evaluated
in
an
impact
assessment.

Since
the
initiation
of
the
Methyl
Bromide
Critical
Use
Exemption
process
under
the
Montreal
Protocol,
the
Biological
and
Economic
Analysis
Division
of
the
Office
of
Pesticide
Programs,
in
conjunction
with
the
Office
of
Air
and
Radiation,
has
developed
the
United
States
nomination
for
critical
use
exemptions
from
the
phaseout
of
methyl
bromide.
These
technical
documents
discuss
in
detail
the
benefits
of
methyl
bromide.
The
most
recent
documents
for
commodities
and
structures
may
be
located
at:
http://
www.
epa.
gov/
ozone/
mbr/
CUN2008/
CUN2008_
Commodities.
pdf
and
http://
www.
epa.
gov/
ozone/
mbr/
CUN2008/
CUN2008_
PostHarvest.
pdf
.