Endothall
Occupational
Exposure
Discussion
with
the
Army
Corp
of
Engineers
Meeting
Minutes
July
27,
2005
On
July
27,
2005
EPA
met
with
Kurt
Getsinger
of
the
Army
Corp
of
Engineers
to
discuss
the
aquatic
herbicide
endothall.
Endothall
is
commonly
used
by
the
Army
Corp
for
exotic
weed
management,
and
is
also
the
subject
of
ongoing
research
conducted
by
the
Army
Corp
and
Kurt
Getsinger.
The
Agency
requested
the
meeting
with
the
Army
Corp
to
better
understand
endothall
use
patterns
and
occupational
exposures.

Currently
several
hand­
held
application
scenarios
are
of
concern
to
the
Agency.
The
exposure
scenarios
that
the
Agency
used
in
the
occupational
assessment
are
derived
from
agricultural
application
scenarios
because
aquatic
data
is
not
available.
The
technical
registrant,
Cerexagri,
commented
that
the
exposure
scenarios
used
are
not
indicative
of
typical
endothall
applications,
particularly
the
amount
of
area
treated.
The
Army
Corp
was
able
to
describe
typical
applications
for
the
Agency
to
use
in
refining
their
application
exposure
estimates.

To
assess
applications
to
lakes,
the
Agency
assumed
that
a
depth
of
5
feet
and
an
area
up
to
30
acres
per
day
could
be
treated
by
an
applicator
making
an
application
with
hand­
held
equipment.
Both
the
registrant
and
the
Army
Corp
commented
that
it
is
unlikely
an
area
this
large
would
be
treated
by
hand.
The
Army
Corp
commented
that
this
was
likely
a
2
to
4
fold
exaggeration
of
typical
application
scenarios.
The
Agency
commented
that
for
2,4­
D
surface
treatments,
10
acres
per
day
was
the
assumption
used
to
assess
hand­
held
applications.
In
addition,
the
Army
Corp
agreed
that
it
was
unlikely
that
a
depth
of
5
feet
would
be
treated,
especially
because
handheld
applications
are
primarily
used
to
spot­
treat
heavy
infestations
of
aquatic
vegetation
that
is
commonly
close
to
the
surface.

To
assess
hand­
held
applications
to
canals,
the
Agency
assumed
that
an
area
of
40
miles
per
day
could
be
treated.
Both
the
Army
Corp
and
the
registrant
commented
that
this
area
was
too
large
to
be
treated
by
hand
in
a
single
day,
and
that
it
was
not
typical
practice
to
make
such
a
large
application
using
hand­
held
equipment.
Mr.
Getsinger
commented
that
40
miles
per
day
was
likely
a
2
to
4­
fold
exaggeration
of
typical
scenarios.

Due
to
the
characterization
of
applications
by
the
Army
Corp,
and
the
Agency's
understanding
the
hand­
held
applications
are
typically
made
to
limited
areas
as
spottreatments
the
Human
Health
Division
is
exploring
the
use
of
the
smaller
areas
treated
in
the
occupational
risk
assessment.
It
has
been
recommended
by
the
Agency
and
the
Army
Corp
that
the
hand­
held
exposure
scenarios
are
similar
to
those
used
in
the
2,4­
D
occupational
risk
assessment,
incorporating
reduced
areas
of
treatment.
