UNITED
STATES
ENVIRONMENTAL
PROTECTION
AGENCY
WASHINGTON,
D.
C.
20460­
0001
OFFICE
OF
PESTICIDES
PROGRAMS
October
27,
2003
John
J.
Jachetta,
Ph.
D
Regulatory
Manager
Regulatory
Success­
America
Dow
AgroSciences
LLC
9330
Zionsville
Road
Indianapolis,
IN
46268­
1050
Dear
Dr.
Jachetta:

The
purpose
of
this
letter
is
to
advise
you
of
the
results
of
EPA's
reevaluation
of
the
terms
of
the
phase­
out
of
chlorpyrifos
methyl
(
CPM).
The
reevaluation
resulted
from
a
meeting
with
representatives
of
USDA's
Office
of
Pesticide
Policy
and
others
in
March
of
this
year
where
the
USDA
requested
that
the
phase­
out
of
Reldan
4E
®
be
extended
until
Codex
MRLs
for
alternatives
were
established.
Further,
they
noted
the
effectiveness
of
combination
products
which
include
lower
concentrations
of
CPM
plus
an
alternative
compound.

The
Agency's
2001
decision
on
CPM
provided
a
phase­
out
of
the
43%
liquid
formulation
end
use
product
Reldan
4E
®
.
Under
the
phase­
out
schedule,
Dow
AgroScience
could
sell,
and
distribute
this
product
through
December
31,
2003,
and
the
last
use
date
is
December
31,
2004.
The
Agency
recognized
the
importance
of
CPM
to
grain
storage,
particularly
for
on­
farm
storage
and
the
smaller
country
elevators,
and
allowed
for
a
phase­
out
in
order
to
transition
to
alternative
means
of
pest
control.
As
a
condition
of
the
phase­
out,
EPA
required
additional
studies
to
better
characterize
risk
associated
with
CPM,
and
Dow
AgroSciences
has
provided
an
acute
delayed
neurotoxicity
study,
and
a
two­
generation
rat
reproduction
study.
These
studies
have
been
received
and
are
currently
being
reviewed.

The
Agency
agreed
in
the
IRED
to
reevaluate
the
phase­
out
in
2003
to
determine
if
viable
alternatives
were
available,
and
extend
the
phase­
out
if
it
were
determined
that
no
adequate
alternatives
were
available.
Since
the
IRED
was
signed,
a
few
new
chemicals
have
come
on
the
market
that
are
promising
for
stored
grain.
However,
many
of
these
new
chemicals
lack
Codex
MRLs,
thus
effectively
limiting
their
use
to
crops
that
are
not
exported.
Also,
the
Agency
reevaluated
its
decision
on
whether
the
database
for
chlorpyrifos
ethyl
(
CPY)
was
adequate
to
address
data
gaps
for
CPM.
­
2­
The
Agency
has
reconsidered
the
toxicity
data
gaps
identified
in
the
CPM
Toxicology
Chapter
of
the
RED
dated
April
19,
2000,
and
concluded
that
CPM
is
likely
to
be
less
toxic
than
CPY
based
on
a
side­
by­
side
comparison
of
cholinesterase
inhibition
levels
in
existing
studies
(
See
Chlorpyrifos
Methyl:
Status
of
Toxicity
Data
Gaps,
Impact
of
New
Data
on
the
Risk
Assessment
and
Impact
on
Cumulative
Risk
Assessment,
July
8,
2003
which
is
attached).
We
have
also
concluded
that
given
the
structural
similarities
between
the
two
chemicals,
toxicity
data
generated
using
CPY
could
be
used
to
address
data
gaps
for
CPM
with
the
exception
of
the
acute
toxicity
test
requirements.
CPM
will
continue
to
be
regulated
using
its
specific
endpoints,
and
the
10x
database
uncertainty
factor
will
be
retained.
This
uncertainty
factor
is
consistent
with
the
10x
on
CPY
which
is
based
on
a
weight­
of­
the
evidence
approach
to
sensitivity.
EPA
has
also
concluded
that
retaining
CPM
on
stored
grain
will
not
have
an
impact
on
the
Organophosphate
Cumulative
Risk
Assessment.

Based
on
this
information,
the
Agency
has
determined
that
the
database
for
CPY
is
adequate
to
assess
the
risk
associated
with
CPM,
and
CPM
is
eligible
for
reregistration.
The
CPY
database
addresses
the
data
requirements
for
CPM
with
the
exception
of
product­
specific
acute
toxicity
data.

The
Agency
will
extend
the
phase­
out
of
Reldan
4
®
through
December
2004.
According,
the
last
date
for
sales
and
distribution
of
Reldan
4E
®
is
December
31,
2004,
and
the
last
use
date
is
December
31,
2005.
This
extension
should
allow
time
for
the
Codex
MRLs
that
are
currently
in
process
for
combination
products
containing
CPM
and
cyfluthrin,
and
spinosad
to
be
approved.

We
intend
to
publish
an
amendment
to
the
IRED
and
the
Federal
Register
Notice
of
April
24,
2002,
to
inform
all
interested
stakeholders
of
EPA's
reevaluation
of
CPM
in
the
near
future.
If
you
have
any
questions,
please
contact
Jackie
Mosby
of
my
staff
at
(
703)
305­
6792.

Sincerely,

Betty
Shackleford,
Acting
Director
Special
Review
&
Reregistration
Division
Enclosures
