UNITED
STATES
ENVIRONMENTAL
PROTECTION
AGENCY
WASHINGTON,
D.
C.
20460
OFFICE
OF
PREVENTION,
PESTICIDES
AND
TOXIC
SUBSTANCES
December
17,
2002
MEMORANDUM
SUBJECT:
EFED
response
to
Bell
Laboratories'
errors­
only
comments
on
the
Agency
document
"
Comparative
Risks
of
Nine
Rodenticides
to
Birds
and
Nontarget
Mammals"

TO:
John
Pates,
Chemical
Review
Manager
Susan
Lewis,
Branch
Chief
FROM:
William
Erickson,
Biologist
Douglas
Urban,
Senior
Biologist
Environmental
Risk
Branch
III,
Environmental
Fate
and
Effects
Division
THRU:
Stephanie
Irene,
Acting
Chief
Environmental
Risk
Branch
III,
Environmental
Fate
and
Effects
Division
The
Environmental
Fate
and
Effects
Division
(
EFED)
has
reviewed
Bell
Laboratories'
30­
day
errors­
only
response
to
the
Agency
document
"
Comparative
Risks
of
Nine
Rodenticides
to
Birds
and
Nontarget
Mammals"
dated
October
3,
2001.
Bell
Laboratories'
comments
of
December
6,
2001
were
prepared
by
C.
W.
Spragins.
As
stated
in
the
Agency's
October
23,
2001
cover
letter
for
the
assessment,
the
registrants'
30­
day
response
should
address
only
mathematical,
computational,
typographic,
or
other
similar
errors.
Matters
of
policy,
interpretation,
or
applicability
of
data
will
be
addressed
after
the
public
comment
period
in
accordance
with
the
Agency's
reregistration
process
for
pesticides.

In
response
to
error
comments
by
Bell
Laboratories,
other
rodenticide
registrants,
and
the
Rodenticide
Registrants
Task
Force,
EFED
has
made
necessary
computational
and/
or
typographical
corrections.
However,
EFED
notes
that
many
comments
relate
to
policy,
interpretation,
or
applicability
of
data,
and
those
comments
will
be
addressed
along
with
public
comments
after
the
60­
day
public­
comment
period.
1
See
December
8­
9,
1998
http://
www.
epa.
gov/
scipoly/
sap/
1998/
index.
htm
2
Dear
Mr.
Pates:

Please
accept
the
following
comments
as
part
of
Bell
Laboratories'
response
to
EPA's
document
entitled
"
Comparative
Risks
of
Nine
Rodenticides
to
Birds
and
Nontarget
Mammals"
(
CRA).
Note
that
further
commentary
from
Bell
will
be
provided
through
the
joint
comments
that
will
be
submitted
shortly
by
the
Rodenticide
Registrants
Task
Force.

1.
Comment:
The
CRA
includes
a
large
amount
of
information
on
the
toxicity
and
possible
hazards
associated
with
consumption
by
mammals
or
birds
of
rodenticides
or
rodents
that
have
consumed
rodenticides.
The
CRA
is
however,
not
a
true
risk
assessment
as
risk
takes
into
consideration
hazard
combined
with
exposure
probability.
Exposure
models
and
probabilities
are
not
considered
in
the
CRA,
hence
it
cannot
be
considered
a
risk
assessment.
The
presumption
of
equal
exposure
in
the
document
is
in
no
way
justified.
As
the
Agency
may
be
aware
some
other
governments
are
looking
at
the
ecological
risks
of
various
pesticides,
including
rodenticides.
In
discussion
of
this
topic
with
the
UK
authorities
who
are
conducting
a
review
at
present,
they
pointed
out
that
they
would
not
jump
to
any
conclusions
or
take
actions
until
they
"
felt
they
had
developed
a
reasonable
model
for
assessing
exposure",
which
they
don't
feel
exists
for
rodenticides
at
present.
A
risk
assessment
cannot
be
completed
without
such
a
model.

EFED
response:
It
is
well
known
that
rodenticide
baits
are
formulated
to
be
lethal
to
rodents
and
a
few
other
small
mammals,
and
they
are
not
selective
to
the
target
species.
Although
many
factors
influence
which
nontarget
animals
might
be
exposed
to
baits,
many
nontarget
organisms
are
attracted
to
and
consume
grain­
based
baits.
Predators
and
scavengers
also
feed
on
rats
and
mice
or
other
target
species,
and
they
are
not
likely
to
avoid
feeding
on
those
that
have
eaten
rodenticide
bait.
Thus,
rodenticide
baits
also
pose
potential
secondary
risks.
EFED
believes
that
the
potential
for
risks
to
birds
and
nontarget
mammals
is
well
established
for
some
of
these
rodenticides.

The
risk
assessment
is
based
on
the
available
data.
Registrants
have
not
submitted
the
data
that
would
be
needed
to
assess
the
probability
of
exposure.
These
data
have
been
outlined
in
a
section
on
Uncertainty
and
Data
Needs
in
the
revised
assessment.
The
methodology
used
is
similar
to
that
used
in
the
Agency's
"
Comparative
Analysis
of
Acute
Risk
From
Granular
Pesticides"
(
EPA
1992)
and
"
A
Comparative
Analysis
of
Ecological
Risks
from
Pesticides
and
Their
Use:
Background,
Methodology,
Case
Study"
(
EPA
1998)
1;
both
were
reviewed
by
a
FIFRA
Scientific
Review
Panel.
Concerning
the
latter
analysis,
the
Panel
noted
the
many
scientific
uncertainties
in
the
method,
yet
agreed
that
it
was
a
useful
screening
tool
that
provides
a
rough
estimate
of
relative
risk.
The
Panel
made
a
number
of
helpful
suggestions
to
improve
the
utility
of
the
method,
most
of
which
are
included
here.
2
See
Guidelines
for
Ecological
Risk
Assessment
(
EPA/
630/
R­
95/
002F,
1998)
at
http://
cfpub.
epa.
gov/
ncea/
cfm/
recordisplay.
cfm?
deid=
12460
3
Risk
conclusions
are
presented
in
tabular
and
graphical
form
based
on
two
analyses
of
the
available
data.
The
first
is
a
comparative
ranking
of
the
potential
risk
based
on
a
comparative­
analysis
model,
and
the
second
is
a
tabular
comparative
rating
of
potential
risk
based
on
a
qualitative
"
weight­
of­
evidence"
assessment.
Quantitative
estimates
of
risk
are
used
in
both;
however,
the
"
weight­
of
evidence"
assessment
includes
qualitative
assessments
of
secondary
risk
based
on
mortality
and
other
adverse
effects
reported
in
laboratory
and
field
studies,
operational
control
programs,
and
incident
reports,
as
well
as
toxicokinetic
data
and
residue
levels
reported
in
primary
consumers.
This
approach
is
in
concert
with
EPA's
risk­
assessment
guidelines2,
where
professional
judgement
or
other
qualitative
evaluation
techniques
may
be
used
to
rank
risks
using
categories
such
as
low,
medium,
and
high
when
exposure
and
effects
data
are
limited
or
are
not
easily
expressed
in
quantitative
terms.

2.
Comment:
The
tone
of
the
CRA
is
disappointingly
biased
for
what
should
be
a
scientifically
objective
review
by
a
government
agency.
It
appears
the
outcome
was
decided
in
advance
and
the
authors
constructed
the
document
to
prove
the
outcome.
In
blunt
terms,
the
CRA
reads
like
a
Brodifacoum
witch
hunt.
The
CRA
includes
presentation
of
many
lab
dosing
studies
wherein
the
investigators
record
relatively
black
and
white
results
which
is
quite
appropriate
provided
they
are
presented
for
what
they
are
(
such
data
encompasses
potential
hazard,
but
only
plays
a
part
in
assessing
overall
risk).
Where
the
picture
gets
particularly
muddled
is
in
the
presentation
of
incident
data
and
in
field
studies
wherein
the
investigators
for
example
go
out
seeking
animals
to
analyze
after
a
product
has
been
used
in
an
actual
treatment
program
for
which
it
is
registered.
Such
data
has
considerably
more
value
in
assessing
actual
risk
but
are
also
much
more
open
to
intepretation,
speculation
and
bias.
It
is
in
the
presentation
of
this
type
of
data
that
the
CRA
falls
woefully
short
of
objectivity
and
the
line
between
fact
and
speculation
is
repeatedly
blurred.
The
authors
give
much
space
and
weight
to
results
from
those
investigators
who
concur
with
the
outcome
that
appears
to
have
been
decided
in
advance.
Some
of
these
investigators
are
openly
biased,
for
example
Ward
Stone
has
stated
publicly
that
he
"
will
see
the
end
of
Brodifacoum".
Charles
Eason
developed
Cholecalciferol
for
the
lucrative
New
Zealand
possum
control
market
and
has
an
interest
in
it's
success.
Brodifacoum
(
and
Compound
1080)
are
direct
and
less
expensive
competitors.
The
Cholecalciferol
product
was
registered
for
possums
in
New
Zealand
in
about
1996,
and
since
that
time,
Mr.
Eason
has
generated
an
ongoing
stream
of
studies
and
papers
directed
at
the
hazards
of
Brodifacoum
use.
While
the
authors
of
the
CRA
subject
the
considerable
amount
of
information
and
analysis
submitted
by
the
RRTF
to
only
brief
review
and
harsh
criticism,
there
appears
to
be
little
critical
analysis
of
the
cited
data
that
concurs
with
the
apparently
predetermined
outcome.
While
the
Agency
might
argue
that
registrants
also
4
have
an
"
agenda",
registrants'
data
has
always
been
subjected
to
far
more
critical
review
by
the
Agency
than
that
of
those
who
oppose
pesticides
or
certain
pesticides,
and
are
thus
forced
to
be
far
more
scientifically
certain
of
their
results
presented.

EFED
response:
This
is
not
an
errors
response.
EFED
believes
that
the
risk
assessment
presents
an
accurate
balance
of
results
from
available
reports
and
the
contention
that
it
is
biased
is
unsupported.
EFED
notes
that
the
peer
reviews
and
the
credentials
of
the
peer
reviewers
will
be
available
in
the
public
docket.

3.
Much
of
the
data
presented
in
the
second
category
as
noted
above
(
incident
and
actual
field
data)
are
from
outside
the
United
States
where
the
use
patterns
are
completely
different.
For
example,
Eason's
New
Zealand
work
refers
to
broadcast
uses
over
large
land
areas.
Field
(
noncommensal
uses
do
not
exist
in
the
U.
S.
for
Brodifacoum,
or
other
second
generation
compounds
(
except
in
the
tiny
exception
of
specific
island
restoration,
which
is
irrelevant
in
the
context
of
the
CRA
as
such
uses
undergo
extensive
evaluation
for
ecologial
impact
on
a
specific
case
by
case
basis
before
they
are
approved.
It
is
interesting
that
the
authors,
while
mentioning
the
island
use,
fail
to
state
that
the
purpose
of
such
use
is
to
actually
preserve
the
native
fauna
and
flora
­
i.
e.
a
benefit
of
rodenticides.
Brodifacoum
is
most
often
chosen
for
such
uses
due
to
its
very
high
level
of
effectiveness).
The
CRA
contains
other
examples
of
data
from
uses
which
do
not
exist
in
the
U.
S.
as
well,
and
fails
overall
to
transparently
make
the
distinction.
Again,
such
data
are
useful
in
assessing
hazard,
but
must
be
viewed
very
carefully
in
assessing
actual
risk.

EFED
response:
This
is
not
an
errors
response.
EFED
notes
that
the
field
studies
are
presented
in
a
hazard
context
and
confirm
the
potential
for
adverse
effects
in
exposed
nontarget
animals,
regardless
of
the
use
pattern
or
location.
The
Agency
believes
that
the
description
of
the
field
studies
and
their
results
provide
useful
information
on
the
effects
of
rodenticides
used
outdoors.

4.
The
CRA
makes
repeated
reference
to
an
"
2­
gram
bait
pellet"
or
a
2­
gram
grain,
eg.
an
oat
groat
and
uses
this
to
state
that
a
"
single
pellet
or
grain"
can
deliver
a
lethal
dose
­
an
incorrect
statement.
These
numbers
are
grossly
inaccurate
­
all
of
Bell's
commensal
use
pellets
are
0.2
g
or
less
and
the
vast
majority
of
field
use
pellets
as
well
(
a
very
large
pellet,
approaching
2
g,
was
used
for
the
Anacapa
island
restoration
project).
Oats
groats
are
about
0.1
g
each.
Conversely,
the
Agency
chooses
a
25
g
non­
target
mammal
for
its
calculations,
which
is
at
the
extreme
bottom
end
of
the
spectrum
of
mammals
(
only
mice
are
that
small
as
adults
and
they
are
typically
the
target
species).

EFED
response:
The
size
of
the
bait
pellet
has
been
corrected
in
the
revised
assessment.
