RED
FACTS;
MCPB
EPA
738­
R­
06­
011
March
2006
All
pesticides
sold
or
distributed
in
the
United
States
must
be
registered
by
EPA,
based
on
scientific
studies
showing
that
they
can
be
used
without
posing
unreasonable
risks
to
people
or
the
environment.
Because
of
advances
in
scientific
knowledge,
the
law
requires
that
pesticides
first
registered
before
November
1,
1984,
be
reregistered
to
ensure
that
they
meet
today's
more
stringent
standards.

In
evaluating
pesticides
for
reregistration,
EPA
obtains
and
reviews
a
complete
set
of
studies
from
pesticide
producers
that
describe
the
human
health
and
environmental
effects
of
each
pesticide.
To
implement
provisions
of
the
Food
Quality
Protection
Act
(
FQPA)
of
1996,
EPA
considers
the
special
sensitivity
of
infants
and
children
to
pesticides,
as
well
as
aggregate
exposure
of
the
public
to
pesticide
residues
from
all
sources,
and
the
cumulative
effects
of
pesticides
and
other
compounds
with
common
mechanisms
of
toxicity.
The
Agency
develops
any
mitigation
measures
or
regulatory
controls
needed
to
effectively
reduce
each
pesticide's
risks.
EPA
then
reregisters
pesticides
that
meet
current
human
health
and
safety
standards
and
can
be
used
without
posing
unreasonable
risks
to
human
health
and
the
environment.

When
a
pesticide
is
eligible
for
reregistration,
EPA
explains
the
basis
for
its
decision
in
a
Reregistration
Eligibility
Decision
(
RED)
document.
This
fact
sheet
summarizes
the
information
in
the
RED
document
for
the
pesticide
MCPB
(
4­(
2­
methyl­
4­
chlorophenoxy)
butyric
acid)
and
salts,
case
number2365.

Uses
 
MCPB
is
a
phenoxy
herbicide
produced
as
a
sodium
salt
and
an
acid.
 
MCPB
is
registered
for
use
on
pea
crops
before
flowering,
for
post­
emergence
control
of
broadleaf
annual
and
perennial
weeds
including
Canadian
thistle,
buttercup,
mustard,
purslane,
ragweed,
common
lambsquarters,
pigweed,
smartweed,
sowthistle,
and
morning
glory.
 
Application
rates
range
from
0.5
to
1.5
lb
ae/
A
applied
once
per
year.
The
highest
rate
is
used
to
treat
Canada
thistle
at
the
bud
stage.
 
MCPB
is
a
general
use
pesticide
with
no
residential
uses.
 
There
is
one
tolerance
established
for
residues
of
MCPB
per
se
in/
on
peas
at
0.1
ppm
(
40
CFR
§
180.318).
 
Approximately
12,000
pounds
of
MCPB
is
used
annually.
Health
Effects
 
MCPB
has
low
to
moderate
acute
toxicity.
 
MCPB
is
not
a
dermal
sensitizer
and
nor
is
it
irritating
to
the
skin
 
Kidney
and
liver
effects
are
the
most
prevalent
hazard
concerns
for
MCPB.
 
Developmental
and
reproductive
toxicity
studies
do
not
indicate
an
enhanced
sensitivity
or
susceptibility
to
young
animals.
 
Neurotoxicity
effects
were
noted
in
studies
conducted
on
MCPA
(
a
structurally
similar
compound
and
metabolite
of
MCPB),
and
therefore
a
developmental
neurotoxicity
study
is
required
for
MCPB.

Ecological
Effects
 
MCPB
is
not
volatile,
not
persistent,
and
not
likely
to
bioconcentrate
 
MCPB's
acidic/
anionic
nature,
physicochemical
properties,
and
relatively
low
sorption
to
soil
indicate
that
MCPB
is
prone
to
leach
and
runoff.
 
MCPB
is
slightly
to
moderately
toxic
to
freshwater
fish
on
an
acute
basis,
and
slightly
toxic
to
freshwater
invertebrates
on
an
acute
basis.
 
MCPB
is
classified
as
moderately
toxic
to
birds
based
on
data
from
an
acute
oral
gavage
study,
and
it
is
classified
as
practically
non­
toxic
to
birds
on
an
acute
dietary
basis.
 
MCPB
is
classified
as
slightly
toxic
to
practically
non­
toxic
to
mammals
on
an
acute
oral
basis.
However,
developmental
effects
and
maternal
toxicity
were
noted
in
a
developmental
study.
 
MCPB
is
an
herbicide,
and
therefore
plant
toxicity
is
expected.

Risks
 
Acute
and
chronic
dietary
risks
for
food
and
drinking
water
are
below
the
Agency's
level
of
concern
(
i.
e.,
less
than
100
percent
of
the
population
adjusted
dose
(
PAD)).
The
most
highly
exposed
population
subgroup
was
infants
(<
1
years
old),
at
approximately
6%
of
the
acute
PAD
(
at
the
95th
percentile
of
exposure)
and
approximately
10%
of
the
chronic
PAD.
 
Dermal
and
inhalation
risks
to
occupational
handlers
are
below
the
Agency's
level
of
concern
with
baseline
clothing
and
chemical­
resistant
gloves.
 
Risks
to
workers
entering
pea
fields
recently
treated
with
MCPB
to
perform
tasks
such
as
scouting
and
irrigation
are
below
EPA's
level
of
concern
with
a
12­
hour
Restricted
Entry
Interval.
 
No
acute
or
chronic
risks
are
predicted
for
freshwater
fish,
freshwater
invertebrates,
or
marine/
estuarine
fish.
 
There
are
potential
acute
risks
to
small
birds
that
consume
short
grass.
All
other
avian
risk
quotients
are
below
the
Agency's
level
of
concern.
No
chronic
avian
risks
are
predicted
for
MCPB.
 
No
acute
risks
to
mammals
are
predicted
for
MCPB.
However,
EPA's
level
of
concern
is
exceeded
for
chronic
risks
to
mammals
of
all
weight
classes
that
consume
grasses,
broadleaf
forage,
and
small
insects.
 
EPA's
level
of
concern
is
exceeded
for
terrestrial
plants.

Risk
Mitigation
The
following
risk
mitigation
measures
are
required
for
MCPB
to
address
risks
of
concern.

 
To
address
potential
acute
risks
to
small
birds
and
terrestrial
plants,
and
chronic
risks
to
mammals,
EPA
is
requiring
medium
or
coarser
droplet
sizes
to
minimize
the
potential
for
spray
drift.

Regulatory
Conclusion
EPA
has
determined
that
all
supported
uses
of
DCNA
are
eligible
for
reregistration,
provided
that
registrants
implement
risk
mitigation
measures
described
in
the
RED
and
make
required
changes
to
product
labeling
and
provided
that
additional
data
identified
in
Chapter
V
of
the
RED
confirm
this
decision.

For
More
Information
Electronic
copies
of
the
MCPB
RED
and
all
supporting
documents
are
available
in
Docket
#
EPAHQ
OPP­
2005­
0263
at
http://
www.
regulations.
gov
.

For
more
information
about
EPA's
pesticide
reregistration
program,
the
MCPB
RED,
or
reregistration
of
individual
products
containing
MCPB,
please
contact
the
Special
Review
and
Reregistration
Division
(
7508C),
Office
of
Pesticide
Programs,
US
EPA,
Washington,
DC
20460,
telephone
703­
308­
8000.

For
information
about
the
health
effects
of
pesticides,
or
for
assistance
in
recognizing
and
managing
pesticide
poisoning
symptoms,
please
contact
the
National
Pesticide
Information
Center
(
NPIC).
Call
toll­
free
1­
800­
858­
7378,
from
6:
30
am
to
4:
30
am
Pacific
Time,
or
9:
30
am
to
7:
30
pm
Eastern
Standard
Time,
seven
days
a
week.
The
NPIC
internet
address
is
http://
npic.
orst.
edu.
