Ms.
Sonja
Pascatore
3059
Garfield
Road
Jamestown,
New
York
14701
Dear
Ms.
Pascatore,

Thank
you
for
your
letter
regarding
the
reregistration
of
endothall.
Public
comments
that
the
Agency
receives
during
public
comment
periods
are
an
integral
part
of
the
reregistration
process.
It
is
my
understanding
that
a
reply
letter
was
already
sent
to
you
from
Administrator
Johnson's
office.
However,
I
wanted
to
specifically
address
several
of
your
comments,
as
well
as
the
documents
that
you
provided
to
the
Agency.
Below
you
will
find
responses
to
several
of
your
direct
comments.
In
addition,
formal
responses
from
the
Environmental
Fate
and
Effects
Division
and
Health
Effects
Division
are
available
in
the
endothall
docket
(
OPP­
2004­
0370)
that
includes
responses
to
several
of
your
comments.

After
considering
your
comments
which
raise
concerns
about
endothall
concentrations
increasing
in
aquatic
environments
(
a
and
i),
we
reexamined
the
report
cited
and
found
that
it
reported
a
160%
increase
in
dissipation,
not
concentration.
The
study
that
is
referenced
(
Yeo,
1970.
Dissipation
of
Endothall
and
Effects
on
Aquatic
Weeds
and
Fish.
Weed
Science,
18(
2):
282­
284)
indicates
an
overall
decrease
in
endothall
concentrations
over
time.
Initial
concentrations
of
3
ppm
decreased
to
1.15
over
12
days
(
Table
3).

In
response
to
comment
b,
pertaining
to
the
possibility
of
a
small
child
ingesting
endothall
at
doses
that
would
result
in
adverse
health
effects:
The
Agency
is
concerned
with
children
being
exposed
to
pesticides
in
ways
that
would
result
in
health
risks.
However,
as
part
of
the
reregistration
process,
health
risks
resulting
from
labeled
use
patterns
are
assessed.
For
endothall,
a
risk
assessment
was
conducted
to
assess
risks
to
children
and
adults
swimming
in
endothall
treated
water.
Incidental
oral
exposure
estimates
for
adults
and
children
are
below
the
Agency's
level
of
concern.
The
swimming
exposure
scenario
relies
on
very
conservative
assumptions,
including
an
UNITED
STATES
ENVIRONMENTAL
PROTECTION
AGENCY
WASHINGTON,
D.
C.
20460
OFFICE
OF
PREVENTION,
PESTICIDES
AND
TOXIC
SUBSTANCES
exposure
time
of
3
hours
a
day
for
approximately
70
days
for
children
and
300
days
for
adults.
The
Agency
also
expects
exposure
to
swimmers
from
the
dermal
route
to
be
extremely
low.

Regarding
comment
c,
concerning
eye
irritation:
the
active
ingredient
endothall
is
an
eye
irritant
and
can
cause
eye
damage
if
it
comes
in
contact
with
the
eyes.
There
is
a
precautionary
statement
on
all
products
with
endothall
as
its
active
ingredient.
The
precautionary
statement
is
directed
towards
mixers,
loaders,
and
applicators,
which
come
in
direct
contact
with
the
undiluted
product.
Labels
currently
require
the
use
of
eyewear
for
occupational
handlers.
Because
children
are
not
anticipated
to
participate
in
applications
or
other
handler
activities,
the
Agency
did
not
assess
such
risks
to
children.
In
addition,
because
of
typical
use
patterns,
the
Agency
does
not
believe
that
swimmers
(
children
or
adults)
will
be
exposed
to
endothall
at
concentrations
that
would
result
in
eye
irritation.

In
response
to
comment
e,
pertaining
to
toxicity
of
endothall
to
fish:
the
Agency
is
concerned
that
application
of
endothall
to
water
bodies
may
lead
to
fish
kills,
and
this
risk
is
addressed
in
the
ecological
risk
assessment
as
well
as
on
the
product
label.
For
most
applications
to
public
water
bodies,
proper
permitting
must
be
acquired
before
endothall
can
be
applied.
If
a
permit
is
required,
the
applicator
must
inform
the
municipality
in
the
jurisdiction
of
the
risks
associated
with
the
chemical
that
is
to
be
applied.
In
addition,
it
is
not
the
goal
of
endothall
applicators
to
kill
fish,
and
applicators
take
precautions
to
minimize
risks
to
fish.

After
considering
your
comments
regarding
endothall
labels
lacking
a
skull
and
crossbones
warning
sign
(
f),
we
re­
examined
current
labels.
Technical
grade
endothall
is
characterized
as
toxicity
category
I
for
acute
oral
toxicity,
acute
eye
irritation,
and
acute
dermal
irritation.
However,
some
label
language
(
i.
e.,
skull
and
crossbones)
is
based
on
the
acute
toxicity
characteristics
of
the
end­
use
products.
Endothall
end­
use
products
do
not
contain
100%
active
ingredient.
Therefore,
end­
use
products
usually
have
different
toxicity
than
the
active
ingredient.
As
part
of
product
reregistration,
which
follows
active
ingredient
reregistration,
the
registrant
is
required
to
submit
toxicity
studies
that
use
enduse
formulations.
After
the
end­
use
product
toxicity
studies
are
reviewed,
appropriate
label
language
will
be
added
to
end­
use
labels
(
i.
e.,
goggles,
gloves,
etc.).
In
addition,
in
response
to
comment
g,
the
Pesticide
Applicators
Manual
likely
categorizes
endothall
technical
as
toxicity
category
I
for
handler
and
applicator
purposes.
Further,
the
numerous
incident
databases
that
the
Agency
consults
during
the
reregistration
process
contained
relatively
few
incidents
of
illness
due
to
endothall.
No
endothall
related
hospitalizations
have
been
reported
due
to
endothall
use.

In
response
to
comment
h,
regarding
endothall's
carcinogenic
potential:
the
submitted
pages
are
taken
from
the
paper
"
Health
Effects
of
Using
2,4­
D
or
Endothall
is
Lakes"
by
Ruth
W.
Shearer,
Ph.
D,
dated
May
21,
1984.
Only
two
pre­
1980
published
mutagenicity
studies
were
positive.
Prior
to
this
article,
the
only
available
oncogenicity
studies
sponsored
by
the
registrant
were
a
rat
study
by
Industrial
Biotest
Laboratories
(
IBT)
and
an
unidentified
mouse
test.
IBT
was
subsequently
convicted
of
supplying
fraudulent
data
and
IBT
studies
are
not
used
in
EPA
evaluations.
Neither
of
these
studies
were
used
in
the
evaluation
of
endothall
because
they
were
performed
prior
to
1970,
and
the
Federal
Insecticide,
Fungicide,
and
Rodenticide
Act
of
1988
forbids
using
studies
for
pesticide
reregistration
that
were
performed
prior
to
1970.
The
Agency
has
a
complete
set
of
valid
oncogenicity
tests
(
rat
and
mouse)
performed
in
the
80s
and
90s
which
are
negative
for
oncogenic
response.

Again,
thank
you
for
your
comments.
The
Agency
appreciates
carefully
thought
through
comments
such
as
yours
because
they
serve
as
a
way
for
us
to
assure
that
our
evaluation
is
correct.
I
hope
that
the
answers
to
your
comments
are
helpful.
If
you
have
any
further
questions,
feel
free
to
contact
me
at
703­
308­
0041
or
via
email
at
hunter.
mika@
epa.
gov.

Sincerely,

Mika
J.
Hunter
Chemical
Review
Manager
Cc:
Anne
Overstreet
Robert
McNally
Debbie
Edwards
