UNITED
STATES
ENVIRONMENTAL
PROTECTION
AGENCY
WASHINGTON,
D.
C.
20460
OFFICE
OF
PREVENTION,
PESTICIDES
AND
TOXIC
SUBSTANCES
6/
2/
04
MEMORANDUM
Subject:
2,4­
D.
Phase
2
Revisions
to
the
Product
and
Residue
Chemistry
Chapters
of
the
Reregistration
Eligibility
Decision;
Reregistration
Case
No.
0073.
Chemical
I.
D.
No.
030001;
DP
Barcode
No.
D302263.

From:
William
J.
Hazel,
Ph.
D.,
Chemist
Reregistration
Branch
I
Health
Effects
Division
(
7509C)

Through:
Whang
Phang,
Ph.
D.,
Branch
Senior
Scientist
Reregistration
Branch
I
Health
Effects
Division
(
7509C)

To:
William
J.
Hazel,
Ph.
D.,
Risk
Assessor
Reregistration
Branch
I
Health
Effects
Division
(
7509C)

and
Mark
Seaton,
Ph.
D.,
Chemical
Review
Manager
Reregistration
Branch
2
Special
Review
and
Reregistration
Division
(
7508W)

Attached
are
the
Phase
2
Product
and
Residue
Chemistry
Chapters
of
the
2,4­
D
Reregistration
Eligibility
Decision
revised
to
reflect
error
comments
provided
by
the
Industry
Task
Force
for
2,4­
D
Data
and
a
separate
set
of
comments
provided
by
PBI/
Gordon
to
address
2,4­
D­
DEA.
An
Executive
Summary
of
the
Chapters
highlighting
the
conclusions
and
data
gaps
is
presented
below.

Executive
Summary
of
the
2,4­
D
Product
and
Residue
Chemistry
Chapters
Product
Chemistry.
The
outstanding
product
chemistry
data
requirements
for
the
2,4­
D
acid,
salt,
and
ester
products
are
summarized
in
Table
3
of
the
attached
Product
Chemistry
Chapter
of
the
2,4­
D
RED,
and
are
detailed
in
the
attached
data
summary
table.
Provided
that
the
registrants
submit
the
data
required
in
the
attached
data
summary
tables
for
their
T/
TGAI
and
FI
products,
2
and
either
certify
that
the
suppliers
of
beginning
materials
and
the
manufacturing
processes
for
the
2,4­
D
manufacturing­
use
products
have
not
changed
since
the
last
comprehensive
product
chemistry
reviews
or
submit
complete
updated
product
chemistry
data
packages,
HED
has
no
objections
to
the
reregistration
of
2,4­
D
and
its
salts
and
esters
with
respect
to
product
chemistry
data
requirements.

Residue
Chemistry.
2,4­
Dichlorophenoxyacetic
acid
(
2,4­
D)
is
an
alkylchlorophenoxy
herbicide
used
to
control
a
variety
of
broadleaf
weeds.
2,4­
D
may
also
occasionally
be
used
as
a
plant
growth
regulator
or
fungicide.
There
are
nine
active
ingredients
(
AIs)
in
2,4­
D
Reregistration
Case
0073
that
are
components
of
a
registered
pesticide
product
labeled
for
use
on
a
food
or
feed
crop;
these
same
nine
AIs
are
also
being
supported
for
reregistration
by
the
Industry
Task
Force
II
on
2,4­
D
Research
Data
(
hereafter
referred
to
as
Task
Force
II).
These
AIs
are:
the
acid
form
of
2,4­
D,
the
sodium
salt,
four
amine
salts,
and
three
esters.
The
members
of
Task
Force
II
currently
include
Agro­
Gor
Corp
(
jointly
owned
by
Atanor,
S.
A.
and
PBI­
Gordon
Corp.),
Dow
AgroSciences,
and
Nufarm
USA.
In
addition,
USDA's
Interregional
Project
No.
4
(
IR­
4)
is
supporting
the
reregistration
of
a
number
of
minor
crop
uses
for
2,4­
D
and
the
California
Citrus
Quality
Council
(
CCQC)
is
supporting
selected
uses
of
2,4­
D
isopropyl
ester
(
IPE)
on
citrus
fruits.

2,4­
D
is
currently
registered
by
Task
Force
II
members
for
food/
feed
uses
on
a
variety
of
field
and
orchard
crops
and
aquatic
sites.
The
2,4­
D
formulation
classes
registered
for
food/
feed
uses
include
wettable
powders
(
WP),
granules
(
G),
soluble
concentrates
in
both
liquid
(
SC/
L)
and
solid
(
SC/
S)
forms,
and
emulsifiable
concentrates
(
EC).
These
formulations
are
typically
applied
as
broadcast,
banded,
or
directed
(
spray
or
wiper)
applications
during
dormancy
or
preplant,
preharvest,
preemergence,
emergence,
postemergence,
or
postharvest
using
ground
or
aerial
equipment.
Tolerances
are
currently
established
for
residues
of
2,4­
D
per
se
in/
on:
numerous
raw
agricultural
commodity
(
RAC)
human
foods
derived
from
fruits,
grasses,
grains,
nuts,
vegetables,
sugarcane,
cotton,
hops,
and
asparagus
at
0.1
ppm
to
5
ppm;
processed
products
of
sugarcane
(
5
ppm)
and
grains
(
2
ppm);
fish
and
shellfish
at
1.0
ppm
and
potable
water
at
0.1
ppm
[
40
CFR
§
180.142(
a)(
1­
6
and
9­
13)].
A
time­
limited
tolerance
of
0.02
ppm
for
2,4­
D
per
se
in/
on
soybean
seed,
expiration
12/
31/
04,
has
since
been
extended
[
40
CFR
§
180.142(
a)(
11);
FR
Notice
Vol.
67,
No.
46,
March
8,
2002].
A
time­
limited
tolerance
of
0.1
ppm
in/
on
wild
rice
established
under
FIFRA
Section
18
will
expire
12/
31/
05
(
FR
Notice
Vol.
68,
No.
11,
Jan.
16,
2003).
Tolerances
for
residues
in
livestock
commodities
are
currently
established
in
terms
of
residues
of
2,4­
D
and/
or
its
metabolite
2,4­
dichlorophenol
[
40
CFR
§
180.142(
a)(
8)].
The
MARC
has
determined
that
2,4­
D
per
se
is
the
residue
of
concern
in
plant
and
livestock
commodities
as
well
as
drinking
water
and
that
tolerances
listed
at
40
CFR
§
180.142
are
to
be
defined
as
"
residues
of
2,4­
D,
both
free
and
conjugated,
determined
as
the
acid"
(
W.
Hazel/
L.
Taylor,
D293119,
TXR
No.
0052264,
12/
3/
03).

There
are
numerous
2,4­
D
EPs
registered
under
FIFRA
Section
3
to
the
members
of
Task
Force
II.
To
indicate
what
uses
are
being
supported
by
Task
Force
II
members,
they
have
provided
the
Agency
with
a
Master
Label
which
SRRD
determined
would
serve
as
the
universe
of
supported
3
uses
for
reregistration
purposes.
For
each
use
site,
the
Master
Label
generally
summarizes
the
following
information:
forms
of
2,4­
D
being
supported
(
i.
e.
acid,
amine
salts,
and/
or
esters);
types
of
formulations
being
supported
(
i.
e.
EC,
WP,
etc.);
limitations
on
the
type
and
timing
of
application(
s);
allowed
application
equipment;
reentry
interval
(
REI);
maximum
single
and
seasonal
application
rates;
minimum
retreatment
interval
(
RTI);
regional
restrictions;
and
restrictions
on
the
preharvest
and
grazing
intervals
(
PHI
and
PGI).
The
Master
Label
does
not
provide
details
for
uses
on
labels
of
specific
EPs.
A
very
brief
summary
of
several
representative
label
directions
for
use
on
major
crops
include:
(
i)
small
grains,
1.25
+
0.5
lb
ae/
A
postemergence
+
preharvest,
14­
d
PHI,
<
1.75
lb
ae/
A/
season;
(
ii)
field
corn,
1
+
0.5
+
1.5
lb
ae/
A
pre­
+
postemergence
+
preharvest,
7­
d
PHI,
<
3
lb
ae/
A/
season;
(
iii)
pasture
and
range,
2
lb
ae/
A
postemergence,
7­
d
precutting
interval;
(
iv)
grapes,
1.36
lb
ae/
A,
postbloom,
100­
d
PHI;
orchard
fruits
and
nuts,
2
x
2
lb
ae/
A
postemergence/
yr,
14­
d
PHI
for
pome
fruits,
40­
d
for
stone
fruits,
and
60­
d
PHI
for
nuts;
and
(
v)
citrus
plant
growth
regulator
use,
12­
200
ppm
foliar
application
with
7­
day
PHI,
500
ppm
postharvest
application
with
no
PHI.

For
the
purposes
of
reregistration,
the
following
amendments
are
recommended
to
be
made
to
all
labels
having
the
designated
uses
of
2,4­
D:
(
i)
directions
for
preharvest
uses
on
citrus
in
the
U.
S.
should
be
restricted
to
AZ
and
CA
and
should
list
a
maximum
use
rate
of
0.27
lb
ae/
A/
crop
cycle;
(
ii)
a
7­
day
PHI
should
be
specified
for
corn
forage
(
all
types);
(
iii)
for
uses
on
stone
fruits,
tree
nuts,
and
pistachios,
the
maximum
single
use
rate
should
be
reduced
to
1.4
lb
ae/
A,
and
the
maximum
seasonal
use
rate
should
be
reduced
to
2.8
lb
ae/
A;
(
iv)
all
labels
bearing
aquatic
uses
should
be
amended
to
indicate
that:
(
a)
all
treated
bodies
of
water
to
be
used
or
likely
to
be
used
as
a
drinking
water
source
must
be
demonstrated
to
contain
2,4­
D
at
<
70
ppb
using
an
approved
assay
before
diversion
for
drinking
water
may
occur;(
b)
the
aquatic
uses
of
2,4­
D
should
be
restricted
to
Federal,
State,
or
local
agencies
or
applicators
under
their
control;
and
(
c)
when
treating
moving
bodies
of
water,
applications
must
be
made
while
traveling
upstream
to
prevent
concentration
of
2,4­
D
downstream
from
the
application.
The
1500­
foot
setback
proposed
on
the
Master
Label
may
optionally
be
specified
on
labels
bearing
an
aquatic
use
as
an
additional
means
of
mitigating
2,4­
D
exposure
via
drinking
water
although
this
restriction
alone
does
not
reliably
reduce
dietary
risk
to
an
acceptable
level.
An
interested
party
may
choose
to
propose
and
support
a
longer
drinking
water
intake
setback
distance
if
demonstrated
to
be
practical,
enforceable,
and
reduce
exposure
significantly.
(
v)
all
labels
bearing
pasture
and
range
(
grass
forage/
hay)
uses
should
prescribe
a
3­
day
pregrazing
interval
for
dairy
animals
as
milk
residues
3
days
after
the
last
day
of
dosing
in
a
feeding
study
were
used
for
milk
tolerance
reassessment
and
the
dietary
exposure
assessment.
A
similar
PGI
is
not
considered
to
be
practical
or
enforceable
for
meat
animals.
The
3­
day
preslaughter
interval
(
PSI)
on
all
labels
bearing
pasture
and
range
uses
should
be
deleted
because
this
is
not
considered
to
be
practical
or
enforceable.

In
addition,
HED
notes
that,
according
to
the
Master
Label,
the
Task
Force
II
is
not
supporting
the
use
of
2,4­
D
esters
on
pistachios,
filberts,
and
other
tree
nut
crops.
However,
adequate
residue
data
are
available
supporting
the
use
of
ester
forms
of
2,4­
D
on
these
crops.
Therefore,
4
labels
for
the
ester
forms
of
2,4­
D
may
include
use
directions
for
pistachios,
tree
nuts,
and
filberts
(
sucker
control)
if
a
party
is
interested
in
labeling
for
such
uses.

Also,
a
40­
day
PHI
is
presently
being
specified
for
stone
fruits.
However,
the
available
residue
data
indicate
that
residues
are
<
LOQ
(<
0.05
ppm)
at
a
14­
day
posttreatment
interval.
Therefore,
strictly
from
a
residue
chemistry
perspective,
the
PHI
for
stone
fruits
could
be
reduced
to
14
days
without
affecting
the
tolerance
level.

The
supported
use
on
grapes
is
restricted
to
CA
only;
however,
adequate
field
trial
data
reflecting
use
of
2,4­
D
amine
salts
are
available
for
the
entire
U.
S.
Therefore,
labels
for
the
acid
and
amine
salt
forms
of
2,4­
D,
strictly
from
a
residue
chemistry
perspective,
do
not
need
to
restrict
the
use
on
grapes
to
only
CA.

The
reregistration
requirements
for
plant
and
livestock
metabolism
are
fulfilled.
Adequate
metabolism
studies
are
available
depicting
the
qualitative
nature
of
the
residues
in
three
dissimilar
crops
(
lemon,
potato,
and
wheat),
the
goat,
and
the
hen.
Based
on
the
available
data,
on
9/
3/
03,
the
MARC
determined
that
the
residue
of
concern
in
plants
and
livestock
for
both
tolerance
expression
and
risk
assessment
purposes
is
2,4­
D,
free
and
conjugated,
determined
as
the
acid
(
W.
Hazel
and
L.
Taylor,
12/
3/
03,
D293128,
TXR
No.
0052264).

Adequate
methods
are
available
for
data
collection
and
the
enforcement
of
plant
commodity
tolerances.
Task
Force
II
submitted
an
adequate
proposed
GC/
ECD
enforcement
method
for
plants
(
designated
as
EN­
CAS
Method
No.
ENC­
2/
93,
described
below)
which
has
been
independently
validated
and
radiovalidated.
Two
separate
(
but
essentially
comparable)
proposed
enforcement
methods
were
submitted
for
determination
of
2,4­
D
in
livestock
commodities.
These
have
been
adequately
radiovalidated.
The
Agency
concluded
that
the
methods
are
adequate
provided
the
registrants
satisfactorily
address
two
minor
issues.
The
10/
97
edition
of
FDA
PAM
Volume
I,
Appendix
I
indicates
that
2,4­
D
is
partially
recovered
(
50­
80%)
using
Multiresidue
Methods
Section
402
E1
and
402
E2.

The
reregistration
requirements
for
magnitude
of
the
residue
in
plants
have
been
evaluated
and
deemed
fulfilled
for
the
following
raw
agricultural
commodities
(
RACs):
almonds
and
almond
hulls;
apples;
asparagus;
aspirated
grain
fractions
(
corn
and
wheat
grain);
blueberries;
cherries;
corn
(
field)
grain,
forage,
and
stover;
corn
(
sweet)
K+
CWHR;
cranberries;
filberts;
grapes;
grapefruit
(
preharvest);
grass
forage
and
hay;
hops,
lemons
(
pre­
and
postharvest);
oranges
(
preand
postharvest);
peaches;
pears;
pecans;
pistachios,
plums/
fresh
prunes;
potatoes;
rice
grain
and
straw;
wild
rice
grain;
sorghum
grain,
forage,
and
stover;
soybean
forage,
hay,
and
seeds;
strawberries;
sugarcane;
and
wheat
grain,
forage,
and
straw.

Overall,
acceptable
field
trials
were
performed
representing
the
maximum
registered
use
patterns
and
conditions
under
which
the
pesticide
could
be
applied.
The
geographic
representation
for
each
commodity
is
generally
adequate,
and
a
sufficient
number
of
trials
reflecting
representative
5
formulation
classes
were
conducted.
Additional
field
trials
are
required
only
for
wheat
hay,
which
will
be
translated
to
several
other
small
grain
crops.

The
reregistration
requirements
for
magnitude
of
the
residue
in
the
processed
commodities
of
the
following
crops
have
been
fulfilled:
apples,
barley,
citrus
fruits,
corn,
oats,
plum/
prunes,
potatoes,
rice,
rye,
sorghum,
soybeans,
sugarcane,
and
wheat.
Residues
of
2,4­
D
did
not
concentrate
in
any
regulated
processed
commodities
derived
from
apple,
corn
grain,
plum/
prunes,
and
sorghum
grain.
However,
concentration
of
residues
was
observed
in
regulated
commodities
processed
from
citrus
fruits,
sugarcane,
and
wheat
grain.

The
reassessed
tolerances
for
residues
of
2,4­
D
in/
on
livestock
feed
items
range
from
0.02
ppm
in/
on
soybean
seeds
to
360
ppm
in/
on
grass
forage.
The
maximum
theoretical
dietary
burdens
(
MTDB)
for
beef
and
dairy
cattle
has
been
calculated
to
be
874
ppm,
the
majority
of
which
is
derived
from
the
tolerance
level
for
grass
forage.
Based
on
feeding
studies,
the
2,4­
D
tolerance
in
milk
may
be
reduced
from
0.1
ppm
to
0.05
ppm
whereas
the
2.0­
ppm
tolerance
in
kidney
has
been
reassessed
at
4.0
ppm
and
the
0.2­
ppm
tolerances
in
meat,
fat,
and
meat
byproducts
except
kidney
(
of
cattle,
goats,
horses,
and
sheep)
have
been
reassessed
at
0.3
ppm.
The
MTDB
for
poultry
and
swine
is
1.6
ppm,
based
primarily
on
the
2.0
ppm
tolerance
on
wheat
grain.
The
reregistration
requirements
for
studies
pertaining
to
magnitude
of
the
residue
in
swine
tissues
and
poultry
tissues
and
eggs
have
been
waived
as
there
is
no
reasonable
expectation
of
finite
residues
in
swine
tissues,
poultry
tissues,
and
eggs
[
Category
3
of
40
CFR
§
180.6(
a)(
3)]
when
2,4­
D
is
applied
according
to
registered
use
directions.
Therefore,
tolerances
for
residues
of
2,4­
D
in
poultry
and
swine
commodities
are
not
necessary.
Also,
they
will
be
excluded
from
the
dietary
exposure
assessment.

An
adequate
fish
metabolism
study
is
available
that
fulfills
reregistration
requirements.
In
the
fish
metabolism
study,
the
major
14C­
residue
in
edible
tissues
of
bluegill
sunfish
was
2,4­
D
(
80%
TRR)
along
with
minor
amounts
of
2,4­
DCP
(
7.9%
TRR).
Based
on
these
data,
the
residue
to
be
regulated
in
fish
and
shellfish
is
the
same
as
that
in
livestock,
i.
e.,
2,4­
D,
free
and
conjugated,
determined
as
the
acid
(
W.
Hazel
and
L.
Taylor,
12/
3/
03,
D293128,
TXR
No.
0052264).

Adequate
studies
are
available
depicting
the
magnitude
of
2,4­
D
residues
in
catfish,
bluegill
sunfish,
crayfish,
and
clams
exposed
to
water
containing
6.0
ppm
(
1.5x)
of
2,4­
D
in
a
static
system.
Based
on
these
studies,
tolerances
for
2,4­
D
residues
have
been
reassessed
at
0.1
ppm
in
fish
and
1.0
ppm
in
shellfish.

Note
that
EPA's
Office
of
Water
(
OW)
has
established
a
Maximum
Contaminant
Level
(
MCL)
of
0.07
ppm
for
2,4­
D
in
drinking
water.
The
aquatic
use
patterns
currently
being
supported
by
Task
Force
II
also
prohibit
the
use
of
2,4­
D
treated
water
for
use
as
potable
water
unless
an
approved
assay
indicates
that
2,4­
D
concentrations
are

0.07
ppm.
The
0.1­
ppm
tolerance
in
potable
water
[
40
CFR
180.142(
a)(
13)]
should
be
revoked
as
levels
of
contaminants
in
drinking
water
are
now
under
the
regulatory
purview
of
OW
as
opposed
to
OPP.
6
The
aquatic
use
patterns
currently
being
supported
by
Task
Force
II
prohibit
the
use
of
2,4­
D
treated
water
for
irrigation
unless
an
approved
assay
indicates
that
2,4­
D
concentrations
are

0.1
ppm.
Irrigated
crop
data
are
sufficient
to
establish
tolerances
in
all
crops
except
sugar
beet
and
perennial
crops
(
to
be
represented
by
strawberry).
A
number
of
direct­
treated
crop
tolerances
are
high
enough
to
accomodate
any
additional
2,4­
D
residues
that
may
be
incurred
by
irrigation
with
treated
water.

The
reregistration
requirements
for
confined/
field
rotational
crop
studies
are
fulfilled.
The
available
confined
rotational
crop
data
indicate
that
additional
field
trials
are
not
required.
In
addition,
no
rotational
crop
tolerances
are
necessary,
and
no
plantback
intervals
following
2,4­
D
application
are
needed.
The
majority
of
the
14C­
residues
in
confined
crop
studies
were
characterized
as
either
aqueous
soluble
or
unextractable
and
reflected
the
incorporation
of
radioactivity
into
natural
components.
The
only
residues
detected
in
any
matrix
were
2,4­
D
and
2,4­
dichloroanisole,
both
at
very
low
levels.

The
following
confirmatory
data
are
recommended:
wheat
hay
field
trials
and
limited
irrigated
crop
studies
(
sugar
beet
roots
and
tops
and
strawberry)
are
recommended
to
support
tolerance
establishment/
reassessment
associated
with
the
use
patterns
currently
supported
by
Task
Force
II.

cc:
L.
Taylor
(
HED),
T.
Dole
(
HED),
Tom
Myers
(
SRRD)
7509C:
RRB2:
WJHazel:
wjh:
CM#
2:
Rm
722J:
305­
7677:
6/
2/
04
WPhang:
6/
2/
04
