United
States
Prevention,
Pesticides
EPA
738­
R­
06­
014
Environmental
Protection
and
Toxic
Substances
July
2006
Agency
(
7509P)

Reregistration
Eligibility
Decision
(
RED)
for
Inorganic
Chlorates
ii
REREGISTRATION
ELIGIBILITY
DECISION
for
Inorganic
Chlorates
Case
No.
4049
Approved
by:

______________________
Debra
Edwards,
Ph.
D.
Director,
Special
Review
and
Reregistration
Division
________________________
Date
iii
TABLE
OF
CONTENTS
Inorganic
Chlorates
Reregistration
Eligibility
Decision
Team....................................................
v
Glossary
of
Terms
and
Abbreviations
.......................................................................................
vi
Abstract
..................................................................................................................................
viii
I.
Introduction.......................................................................................................................
1
II.
Chemical
Overview
.......................................................................................................
3
A.
Regulatory
History
........................................................................................................
3
B.
Chemical
Identification
 
Sodium
Chlorate
.................................................................
3
C.
Use
Profile......................................................................................................................
3
D.
Estimated
Usage
of
Sodium
Chlorate
...........................................................................
4
III.
Summary
of
Inorganic
Chlorates
Risk
Assessments
.......................................................
6
A.
Human
Health
Risk
Assessment
.....................................................................................
6
1.
Toxicity
of
Sodium
Chlorate
.......................................................................................
6
2.
Carcinogenicity
of
Sodium
Chlorate
...........................................................................
9
3.
Sodium
Chlorate
Endocrine
Effects
.......................................................................
10
4.
Metabolites
and
Degradates
....................................................................................
10
5.
Dietary
Exposure
and
Risk
(
Food)............................................................................
11
6.
Dietary
Exposure
and
Risks
(
Drinking
Water)
......................................................
13
7.
Residential
Exposure
and
Risk
...............................................................................
17
8.
Aggregate
Risk.........................................................................................................
20
9.
Occupational
Exposure
and
Risk............................................................................
21
B.
Environmental
Fate
and
Effects
Risk
Assessment
.....................................................
27
1.
Environmental
Fate
and
Transport
........................................................................
27
2.
Ecological
Exposure
and
Risk...................................................................................
28
IV.
Risk
Management,
Reregistration,
and
Tolerance
Reassessment..................................
40
A.
Determination
of
Reregistration
Eligibility
...................................................................
40
B.
Public
Comments
and
Responses................................................................................
40
C.
Regulatory
Position.......................................................................................................
41
1.
Food
Quality
Protection
Act
Findings.......................................................................
41
2.
Endocrine
Disruptor
Effects
...................................................................................
42
3.
Cumulative
Risks.....................................................................................................
42
4.
Endangered
Species.................................................................................................
43
D.
Tolerance
Reassessment
Summary.........................................................................
44
E.
Regulatory
Rationale...................................................................................................
46
1.
Human
Health
Risk
Management
..........................................................................
46
2.
Non­
Target
Organism
(
Ecological)
Risk
Management..........................................
52
3.
Summary
of
Mitigation
Measures
..........................................................................
57
F.
Other
Labeling
Requirements
....................................................................................
58
1.
Endangered
Species
Considerations
.......................................................................
58
2.
Spray
Drift
Management
........................................................................................
59
V.
What
Registrants
Need
to
Do
.........................................................................................
60
A.
Manufacturing­
Use
Products......................................................................................
60
1.
Generic
Data
Requirements
....................................................................................
60
2.
Labeling
for
Manufacturing­
Use
Products.............................................................
61
B.
End­
Use
Products........................................................................................................
61
1.
Additional
Product­
Specific
Data
Requirements
...................................................
61
iv
2.
Labeling
for
End­
Use
Products...............................................................................
61
C.
Labeling
Changes
Summary
Table.............................................................................
61
D.
Existing
Stocks.............................................................................................................
61
v
Inorganic
Chlorates
Reregistration
Eligibility
Decision
Team
Biological
and
Economic
Analysis
Assessment
Rafael
Prieto
Alan
Halvorson
Nicole
Zinn
Andrew
Lee
Environmental
Fate
and
Effects
Risk
Assessment
Brian
Anderson
Silvia
Termes
Jim
Goodyear
Stephanie
Syslo
Health
Effects
Risk
Assessment
Susan
Hummel
Bonnie
Cropp­
Kohlligian
Abdullah
Khasawinah
Matthew
Crowley
Thurston
Morton
Gary
Otakie
Registration
Support
Juanita
Gilchrist
Jim
Tompkins
Risk
Management
Molly
Clayton
Kimberly
Nesci
Office
of
General
Counsel
Erin
Koch
vi
Glossary
of
Terms
and
Abbreviations
a.
i.
Active
Ingredient
aPAD
Acute
Population
Adjusted
Dose
APHIS
Animal
and
Plant
Health
Inspection
Service
ARTF
Agricultural
Re­
entry
Task
Force
BCF
Bioconcentration
Factor
CDC
Centers
for
Disease
Control
CDPR
California
Department
of
Pesticide
Regulation
CFR
Code
of
Federal
Regulations
ChEI
Cholinesterase
Inhibition
CMBS
Carbamate
Market
Basket
Survey
cPAD
Chronic
Population
Adjusted
Dose
CSFII
USDA
Continuing
Surveys
for
Food
Intake
by
Individuals
CWS
Community
Water
System
DCI
Data
Call­
In
DEEM
Dietary
Exposure
Evaluation
Model
DL
Double
layer
clothing
{
i.
e.,
coveralls
over
SL}
DWLOC
Drinking
Water
Level
of
Comparison
EC
Emulsifiable
Concentrate
Formulation
EDSP
Endocrine
Disruptor
Screening
Program
EDSTAC
Endocrine
Disruptor
Screening
and
Testing
Advisory
Committee
EEC
Estimated
Environmental
Concentration.
The
estimated
pesticide
concentration
in
an
environment,
such
as
a
terrestrial
ecosystem.
EP
End­
Use
Product
EPA
U.
S.
Environmental
Protection
Agency
EXAMS
Tier
II
Surface
Water
Computer
Model
FDA
Food
and
Drug
Administration
FFDCA
Federal
Food,
Drug,
and
Cosmetic
Act
FIFRA
Federal
Insecticide,
Fungicide,
and
Rodenticide
Act
FOB
Functional
Observation
Battery
FQPA
Food
Quality
Protection
Act
FR
Federal
Register
GL
With
gloves
GPS
Global
Positioning
System
HIARC
Hazard
Identification
Assessment
Review
Committee
IDFS
Incident
Data
System
IGR
Insect
Growth
Regulator
IPM
Integrated
Pest
Management
RED
Reregistration
Eligibility
Decision
LADD
Lifetime
Average
Daily
Dose
LC50
Median
Lethal
Concentration.
Statistically
derived
concentration
of
a
substance
expected
to
cause
death
in
50%
of
test
animals,
usually
expressed
as
the
weight
of
substance
per
weight
or
volume
of
water,
air
or
feed,
e.
g.,
mg/
l,
mg/
kg
or
ppm.
LCO
Lawn
Care
Operator
LD50
Median
Lethal
Dose.
Statistically
derived
single
dose
causing
death
in
50%
of
the
test
animals
when
administered
by
the
route
indicated
(
oral,
dermal,
inhalation),
expressed
as
a
weight
of
substance
per
unit
weight
of
animal,
e.
g.,
mg/
kg.
LOAEC
Lowest
Observed
Adverse
Effect
Concentration
LOAEL
Lowest
Observed
Adverse
Effect
Level
LOC
Level
of
Concern
LOEC
Lowest
Observed
Effect
Concentration
mg/
kg/
day
Milligram
Per
Kilogram
Per
Day
MOE
Margin
of
Exposure
MP
Manufacturing­
Use
Product
MRID
Master
Record
Identification
(
number).
EPA's
system
of
recording
and
tracking
studies
submitted.
vii
MRL
Maximum
Residue
Level
N/
A
Not
Applicable
NASS
National
Agricultural
Statistical
Service
NAWQA
USGS
National
Water
Quality
Assessment
NG
No
Gloves
NMFS
National
Marine
Fisheries
Service
NOAEC
No
Observed
Adverse
Effect
Concentration
NOAEL
No
Observed
Adverse
Effect
Level
NPIC
National
Pesticide
Information
Center
NTP
National
Toxicology
Program
NR
No
respirator
OP
Organophosphorus
OPP
EPA
Office
of
Pesticide
Programs
ORETF
Outdoor
Residential
Exposure
Task
Force
PAD
Population
Adjusted
Dose
PCA
Percent
Crop
Area
PDCI
Product
Specific
Data
Call­
In
PDP
USDA
Pesticide
Data
Program
PF10
Protections
factor
10
respirator
PF5
Protection
factor
5
respirator
PHED
Pesticide
Handler's
Exposure
Data
PHI
Preharvest
Interval
ppb
Parts
Per
Billion
PPE
Personal
Protective
Equipment
PRZM
Pesticide
Root
Zone
Model
RBC
Red
Blood
Cell
RAC
Raw
Agricultural
Commodity
RED
Reregistration
Eligibility
Decision
REI
Restricted
Entry
Interval
RfD
Reference
Dose
RPA
Reasonable
and
Prudent
Alternatives
RPM
Reasonable
and
Prudent
Measures
RQ
Risk
Quotient
RTU
(
Ready­
to­
use)
RUP
Restricted
Use
Pesticide
SCI­
GROW
Tier
I
Ground
Water
Computer
Model
SF
Safety
Factor
SL
Single
layer
clothing
SLN
Special
Local
Need
(
Registrations
Under
Section
24(
c)
of
FIFRA)
STORET
Storage
and
Retrieval
TEP
Typical
End­
Use
Product
TSH
Thyroid
Stimulating
Hormone
TGAI
Technical
Grade
Active
Ingredient
TRAC
Tolerance
Reassessment
Advisory
Committee
TTRS
Transferable
Turf
Residues
UF
Uncertainty
Factor
USDA
United
States
Department
of
Agriculture
USFWS
United
States
Fish
and
Wildlife
Service
USGS
United
States
Geological
Survey
WPS
Worker
Protection
Standard
viii
Abstract
The
Environmental
Protection
Agency
(
EPA
or
the
Agency)
has
completed
the
human
health
and
environmental
risk
assessments
for
the
Inorganic
Chlorates
and
is
issuing
its
risk
management
decision
and
tolerance
reassessment.
The
risk
assessments,
which
are
summarized
below,
are
based
on
the
review
of
the
required
target
database
supporting
the
use
patterns
of
currently
registered
products
and
additional
information
received
through
the
public
docket.
After
considering
the
risks
identified
in
the
revised
risk
assessments,
comments
received,
and
mitigation
suggestions
from
interested
parties,
the
Agency
developed
its
risk
management
decision
for
uses
of
inorganic
chlorates
that
pose
risks
of
concern.
As
a
result
of
this
review,
EPA
has
determined
that
inorganic
chlorate­
containing
products
are
eligible
for
reregistration,
provided
that
risk
mitigation
measures
are
adopted
and
labels
are
amended
accordingly.
That
decision
is
discussed
fully
in
this
document.

Sodium
chlorate
is
an
inorganic
salt
herbicide
that
was
first
registered
in
1966.
It
is
a
defoliant
and
a
desiccant
that
is
primarily
used
on
cotton,
but
it
also
has
other
agricultural
and
non­
agricultural
uses.
As
a
non­
selective
herbicide
it
is
used
to
kill
grasses
and
weeds
in
industrial
and
non­
agricultural
sites
such
as
driveways,
tennis
courts,
and
recreational
areas.
The
initial
risk
assessment
indicated
some
ecological
and
occupational
risks
of
concern.
Risk
assessments
were
revised
based
on
refinements
to
the
assessments
as
well
as
mitigation
measures.
Occupational
and
ecological
risks
resulting
from
non­
agricultural
uses
have
been
mitigated
by
reducing
application
rates,
as
well
as
limiting
applications
of
sodium
chlorate
to
spot
treatments
only.
Use
on
rights­
of­
way
and
ditch
banks
will
be
cancelled.
The
Agency
may
require
changes
to
the
language
of
the
sodium
chlorate
label
in
the
future
if
deemed
necessary
under
the
Endangered
Species
Protection
Program.
1
I.
Introduction
The
Federal
Insecticide,
Fungicide,
and
Rodenticide
Act
(
FIFRA)
was
amended
in
1988
to
accelerate
the
reregistration
of
products
with
active
ingredients
registered
prior
to
November
1,
1984.
The
amended
Act
calls
for
the
development
and
submission
of
data
to
support
the
reregistration
of
an
active
ingredient,
as
well
as
a
review
of
all
submitted
data
by
the
U.
S.
Environmental
Protection
Agency
(
referred
to
as
EPA
or
"
the
Agency").
Reregistration
involves
a
thorough
review
of
the
scientific
database
underlying
a
pesticide's
registration.
The
purpose
of
the
Agency's
review
is
to
reassess
the
potential
hazards
arising
from
the
currently
registered
uses
of
the
pesticide,
to
determine
the
need
for
additional
data
on
health
and
environmental
effects,
and
to
determine
whether
or
not
the
pesticide
meets
the
"
no
unreasonable
adverse
effects"
criteria
of
FIFRA.

On
August
3,
1996,
the
Food
Quality
Protection
Act
(
FQPA)
was
signed
into
law.
This
Act
amends
FIFRA
and
the
Federal
Food,
Drug,
and
Cosmetic
Act
(
FFDCA)
to
require
reassessment
of
all
existing
tolerances
for
pesticides
in
food.
FQPA
also
requires
EPA
to
review
all
tolerances
in
effect
on
August
2,
1996,
by
August
3,
2006.
In
reassessing
these
tolerances,
the
Agency
must
consider,
among
other
things,
aggregate
risks
from
non­
occupational
sources
of
pesticide
exposure,
whether
there
is
increased
susceptibility
of
infants
and
children,
and
the
cumulative
effects
of
pesticides
with
a
common
mechanism
of
toxicity.
When
a
safety
finding
has
been
made
that
aggregate
risks
are
not
of
concern
and
the
Agency
concludes
that
there
is
a
reasonable
certainty
of
no
harm
from
aggregate
exposure,
the
tolerances
are
considered
reassessed.
EPA
decided
that,
for
those
chemicals
that
have
tolerances
and
are
undergoing
reregistration,
tolerance
reassessment
will
be
accomplished
through
the
reregistration
process.

Of
the
inorganic
chlorates
listed
as
active
ingredients
(
i.
e.,
sodium
chlorate
(
073301),
calcium
chlorate
(
073302),
potassium
chlorate
(
073303),
and
magnesium
chlorate
(
530200)),
only
sodium
chlorate
is
present
as
an
active
ingredient
in
currently
registered
products.
As
such,
sodium
chlorate
is
the
primary
focus
of
the
reregistration
eligibility
decision.
Sodium
chlorate
is
a
strong
oxidizer
and
may
be
reduced
to
a
variety
of
chemical
species
depending
on
the
environmental
conditions.
As
a
consequence
of
its
reaction
as
an
oxidant,
sodium
chlorate
generates
reduced
chloro
species
(
i.
e.,
chlorine
in
lower
oxidation
states
than
chlorate),
such
as
chlorite
and
hypochlorite.
Since
chlorite
is
also
an
active
ingredient
and
is
being
considered
in
the
chlorite/
chlorine
dioxide
reregistration
eligibility
decision
(
case
number
4043).
The
Agency
will
not
consider
the
tolerances
for
chlorate
reassessed
until
the
assessment
of
chlorite
is
complete.
As
mentioned
above,
FQPA
requires
EPA
to
consider
available
information
concerning
the
cumulative
effects
of
a
particular
pesticide's
residues
and
"
other
substances
that
have
a
common
mechanism
of
toxicity."
Potential
cumulative
effects
of
chemicals
with
a
common
mechanism
of
toxicity
are
considered
because
low­
level
exposures
to
multiple
chemicals
causing
a
common
toxic
effect
by
a
common
mechanism
could
lead
to
the
same
adverse
health
effect
as
would
a
higher
level
of
exposure
to
any
one
of
these
individual
chemicals.

EPA
has
not
made
a
common
mechanism
of
toxicity
finding
as
to
parent
sodium
chlorate
and
any
other
substances,
and
sodium
chlorate
does
not
appear
to
produce
a
toxic
metabolite
that
is
in
common
with
those
produced
by
other
substances.
For
the
purposes
of
this
reregistration
eligibility
decision
(
RED),
therefore,
EPA
has
not
assumed
that
the
inorganic
chlorates
have
a
common
mechanism
of
toxicity
with
other
substances.
For
information
regarding
EPA's
efforts
2
to
determine
which
chemicals
have
a
common
mechanism
of
toxicity
and
to
evaluate
the
cumulative
effects
of
such
chemicals,
see
the
policy
statements
released
by
EPA's
Office
of
Pesticide
Programs
concerning
common
mechanism
determinations
and
procedures
for
cumulating
effects
from
substances
found
to
have
a
common
mechanism
on
EPA's
website
at
http://
www.
epa.
gov/
pesticides/
cumulative/.

This
document
presents
EPA's
revised
human
health
and
ecological
risk
assessments,
its
progress
toward
tolerance
reassessment,
and
the
reregistration
eligibility
decision
for
inorganic
chlorates.
The
document
consists
of
six
sections.
Section
I
contains
the
regulatory
framework
for
reregistration/
tolerance
reassessment;
Section
II
provides
a
profile
of
the
use
and
usage
of
the
chemical;
Section
III
gives
an
overview
of
the
human
health
and
environmental
effects
risk
assessments;
Section
IV
presents
the
Agency's
decision
on
reregistration
eligibility
and
risk
management;
and
Section
V
summarizes
the
label
changes
necessary
to
implement
the
risk
mitigation
measures
outlined
in
Section
IV.
Finally,
the
Appendices
list
related
information,
supporting
documents,
and
studies
evaluated
for
the
reregistration
decision.
The
revised
risk
assessments
for
inorganic
chlorates
are
available
in
the
Office
of
Pesticide
Programs
(
OPP)
public
docket
under
docket
number
OPP­
2005­
0507
available
on
the
Agency's
web
page
at
http://
www.
epa.
gov/
oppsrrd1/
reregistration/
inorganicchlorates/.
3
II.
Chemical
Overview
Of
the
inorganic
chlorates
listed
as
active
ingredients
(
i.
e.,
sodium
chlorate
(
073301),
calcium
chlorate
(
073302),
potassium
chlorate
(
073303),
and
magnesium
chlorate
(
530200)),
only
sodium
chlorate
is
present
as
an
active
ingredient
in
currently
registered
products.
Sodium
chlorate,
calcium
chlorate,
and
potassium
chlorate
are
present
as
inert
ingredients
in
currently
registered
products
and
exposures
as
a
result
of
those
uses
are
addressed
herein.
Sodium
chlorate
is
a
defoliant/
desiccant,
and
is
used
as
an
herbicide.

A.
Regulatory
History
Sodium
chlorate
was
first
registered
in
February
23,
1966
by
Value
Gardens
Supply,
LLC,
for
use
on
both
annual
and
perennial
grasses
and
weeds
for
the
following
non­
agricultural
use
sites:
garage
areas,
tennis
courts,
curbs,
driveways,
walks,
and
patios.
On
October
30,
1968,
Helena
Chemical
Company
registered
it
for
use
as
a
desiccant
on
agricultural
sites
(
sorghum
and
cotton).
Currently,
there
are
56
active
product
registrations
containing
sodium
chlorate
as
an
active
ingredient,
including
11
technical
(
manufacturing
use)
registrations,
and
45
end­
use
products
ranging
from
2.3%
to
99.7%
active
ingredient.
Sodium
chlorate
is
currently
manufactured
by
seven
companies.
The
compound
may
be
used
in
combination
with
other
herbicides,
such
as
atrazine,
2,4­
D,
bromacil,
diuron,
and
sodium
metaborate.

B.
Chemical
Identification
 
Sodium
Chlorate
Chemical
Structure:

Common
Names:
Sodium
chlorate,
soda
chlorate,
chloric
acid,
sodium
salt
Chemical
Name:
Sodium
chlorate
Trade
Names:
Ferti­
Lome,
Barespot,
Tri­
Kil,
Bareground,
Prometon,
Pramitol,
Killsall,
TriChlor
Chemical
Family:
Inorganic
salt
Case
Number:
4049
CAS
Number:
7775­
09­
9
PC
Code:
073301
Molecular
Weight:
106.5
Empirical
Formula:
NaClO3
Technical
Registrants:
EKA
Chemicals,
ERCO
Chemicals,
Kerr­
McGee
Chemical,
Nexen
Chemical
USA,
Moore
Agricultural
Products
Company,
Inc.

C.
Use
Profile
The
following
is
information
on
the
currently
registered
uses
of
sodium
chlorate,
including
an
overview
of
use
sites
and
application
methods.
A
detailed
table
of
the
uses
of
sodium
chlorate
eligible
for
reregistration
is
available
in
Appendix
A.
4
Type
of
Pesticide:
Herbicide
(
desiccant/
defoliant)

Target
Pest:
Broadleaf
weeds
Mode
of
Action:
Non­
selective,
contact
herbicide
that
penetrates
the
cuticle
causing
cell
death
by
altering
the
metabolic
processes.

Use
Sites
Agricultural
uses:
Agriculturally,
it
is
primarily
used
on
cotton;
however,
it
is
also
applied
to
a
wide
variety
of
other
crops
including,
but
not
limited
to,
rice,
corn,
soybeans,
dry
beans,
potatoes,
sunflowers,
flax,
safflower,
chili
peppers
(
for
processing
only),
grain
sorghum,
and
wheat.

Non­
agricultural
Uses:
Sodium
chlorate
is
used
on
nonagricultural
(
residential
and
industrial)
areas
such
as
rights­
of­
ways,
building
perimeters,
ditch
banks,
bleachers,
airport
runways,
vacant
lots,
fire
hydrants,
or
as
a
pre­
paving
treatment.
It
is
also
used
by
a
small
percentage
of
water
treatment
facilities
for
the
generation
of
chlorine
dioxide.

Use
Classification:
General
Use
Formulation
Types:
Agricultural
products
are
all
formulated
as
soluble
concentrates/
liquids;
non­
crop
products
are
formulated
as
soluble
concentrates/
liquids
and
granules
or
pellets/
tablets.

Application
Methods:
Sodium
chlorate
as
a
defoliant/
desiccant
in
agricultural
settings
is
applied
using
aerial
and
groundboom
equipment.
As
an
herbicide
in
nonagricultural
settings,
it
is
applied
using
handheld
equipment
such
as
a
low­
pressure
handwands
or
sprinkling
cans;
it
is
also
applied
via
groundboom
or
handgun
sprayer
application
methods
for
larger
commercial
scenarios.
Granular
formulations
can
be
applied
using
belly
grinders,
push­
type
spreaders,
tractor­
drawn
spreaders,
or
by
hand.

Application
Rates:
In
agriculture,
rates
range
from
6
pounds
active
ingredient
per
acre
(
6
lb
ai/
A)
to
12.5
lbs
ai/
A.
Industrial
and
other
noncrop
site
rates
range
from
132
to
1032
lbs
ai/
A,
based
on
current
labels.
Sodium
chlorate
can
be
applied
multiple
times
per
year.

Application
Timing:
Sodium
chlorate
is
applied
post­
emergence.

D.
Estimated
Usage
of
Sodium
Chlorate
The
primary
non­
pesticidal
use
for
sodium
chlorate
is
as
a
precursor
in
chlorine
dioxide
generation
through
a
closed
system
to
bleach
wood
pulp/
paper.
The
pesticidal
uses
of
sodium
chlorate,
including
the
agricultural
uses
as
a
defoliant/
desiccant,
are
a
small
percentage
(
approximately
2%)
of
the
total
sodium
chlorate
used
in
the
United
States.
According
to
Agency
5
data,
approximately
2.8
million
pounds
of
sodium
chlorate
are
applied
annually
to
agricultural,
residential,
and
commercial
use
sites.
A
screening­
level
usage
analysis
(
SLUA)
of
sodium
chlorate
from
1998
to
2005
indicates
that
approximately
2.1
million
pounds
of
sodium
chlorate
are
used
annually
on
agricultural
use
sites
in
the
United
States.
In
terms
of
pounds
applied,
the
greatest
use
is
on
cotton
(
1.9
million
lbs
ai
per
year);
annually
this
represents
approximately
5
percent
of
cotton
acreage
treated.

Exposure
to
the
chlorate
may
also
occur
as
a
result
of
the
drinking
water
disinfection
process.
This
use
and
resulting
exposure
are
explained
in
detail
in
this
document.
6
III.
Summary
of
Inorganic
Chlorates
Risk
Assessments
The
following
is
a
summary
of
EPA's
revised
human
health
and
ecological
risk
assessments
for
inorganic
chlorates,
as
presented
fully
in
the
documents,
revised
Inorganic
Chlorates.
HED
Chapter
of
the
Reregistration
Eligibility
Decision
Document
(
RED),
dated
January
26,
2006,
and
the
revised
Sodium
Chlorate
Ecological
Risk
Assessment,
dated
June
1,
2006.
The
purpose
of
this
summary
is
to
assist
the
reader
by
identifying
the
key
features
and
findings
of
these
risk
assessments,
and
to
help
the
reader
better
understand
the
conclusions
reached
in
the
assessments.

The
human
health
and
ecological
risk
assessment
documents
and
supporting
information
listed
in
Appendix
C
were
used
to
reach
the
safety
finding
and
regulatory
decision
for
sodium
chlorate.
While
the
risk
assessments
and
related
addenda
are
not
included
in
this
document,
they
are
available
from
the
OPP
Public
Docket,
located
at
http://
www.
regulations.
gov,
under
docket
number
EPA­
HQ­
OPP­
2005­
0507.

EPA's
use
of
human
studies
in
the
sodium
chlorate
risk
assessment
is
in
accordance
with
the
Agency's
Final
Rule
promulgated
on
January
26,
2006,
related
to
Protections
for
Subjects
in
Human
Research,
which
is
codified
in
40
CFR
Part
26.

A.
Human
Health
Risk
Assessment
The
human
health
risk
assessment
incorporates
potential
exposure,
hazard,
and
risks
from
all
sources,
which
include
food,
drinking
water,
residential
(
if
applicable),
and
occupational
scenarios.
Aggregate
assessments
combine
food,
drinking
water,
and
any
residential
or
other
non­
occupational
(
if
applicable)
exposures
to
determine
potential
exposures
to
the
U.
S.
population.
The
Agency's
human
health
assessment
considers
all
U.
S.
populations,
including
infants
and
young
children.
For
more
information
on
the
inorganic
chlorates
human
health
risk
assessment,
see
Revised
Inorganic
Chlorates.
HED
Chapter
of
the
Reregistration
Eligibility
Decision
Document
(
RED)
dated
June
26,
2006.

1.
Toxicity
of
Sodium
Chlorate
Toxicity
assessments
are
designed
to
predict
whether
a
pesticide
could
cause
adverse
health
effects
in
humans
(
including
short­
term
or
acute
effects
such
as
skin
or
eye
damage,
and
lifetime
or
chronic
effects
such
as
cancer,
developmental
effects,
or
reproductive
effects),
and
the
level
or
dose
at
which
such
effects
might
occur.
The
Agency
has
reviewed
all
toxicity
studies
submitted
for
sodium
chlorate
and
has
determined
that
the
toxicological
database
is
complete,
reliable,
and
sufficient
for
reregistration.
For
more
details
on
the
toxicity
and
carcinogenicity
of
the
inorganic
chlorates,
see
Revised
Inorganic
Chlorates.
HED
Chapter
of
the
Reregistration
Eligibility
Decision
Document
(
RED)
dated
January
26,
2006,
which
is
available
under
docket
number
EPA­
HQ­
OPP­
2005­
0507.

a.
Acute
Toxicity
Profile
In
acute
toxicity
tests,
sodium
chlorate
is
slightly
toxic
by
the
oral
(
Toxicity
Category
IV),
dermal
(
Toxicity
Category
III),
and
inhalation
routes
(
Toxicity
Category
IV).
Sodium
chlorate
crystals
were
mildly
irritating
to
the
rabbit
eye
(
Toxicity
Category
III),
and
were
a
7
minimal
to
mild
dermal
irritant
(
Toxicity
Category
III).
Incident
reports
show
that
ingestion
of
toxic
doses
of
sodium
chlorate
by
humans
produces
gastritis,
hemolysis,
methemoglobinemia,
hemoglobinurea,
late
toxic
nephritis,
and
acute
renal
failure.
Doses
in
excess
of
100
mg/
kg
are
generally
fatal
to
humans.
The
acute
toxicity
profile
for
sodium
chlorate
is
summarized
in
Table
1
below.

Table
1.
Acute
Toxicity
Profile
­
Sodium
Chlorate
Guideline
Number
Study
Type
MRID
No.
Results
Toxicity
Categorya
870.1100
Acute
oral
­
Rats
41819901
LD50
 
5000
mg/
kg
(
rat)
IV
870.1200
Acute
dermal
­
Rabbits
42497601
LD50
=
>
2000
mg/
kg
III
870.1300
Acute
inhalation
­
Rats
41819903
LC50
=
5.59
mg/
L
IV
870.2400
Acute
eye
irritation
­
Rabbit
00085090
00102998
41819904
mildly
irritating
III
870.2500
Acute
dermal
irritation
­
Rabbit
42497602
minimally
irritating
III
870.2600
Skin
sensitization
­
guinea
pigs
41819906
not
a
dermal
sensitizer
NA
a.
The
technical
acute
toxicity
values
included
in
this
document
are
for
informational
purposes
only.
The
data
supporting
these
values
may
or
may
not
meet
the
current
acceptance
criteria.

b.
FQPA
Safety
Factor
Considerations
The
Federal
Food,
Drug,
and
Cosmetic
Act
(
FFDCA),
as
amended
by
the
Food
Quality
Protection
Act
(
FQPA),
directs
the
Agency
to
use
an
additional
ten
fold
(
10x)
safety
factor
(
SF)
to
account
for
potential
pre­
and
postnatal
toxicity
and
completeness
of
the
data
with
respect
to
exposure
and
toxicity
to
infants
and
children.
FQPA
authorizes
the
Agency
to
modify
the
10x
FQPA
SF
only
if
reliable
data
demonstrate
that
the
resulting
level
of
exposure
would
be
safe
for
infants
and
children.

For
sodium
chlorate,
based
on
the
hazard
data
and
the
exposure
data,
the
FQPA
SF
was
reduced
to
1x.
There
was
no
pre­
or
postnatal
sensitivity
or
susceptibility
observed
in
the
submitted
developmental
studies
in
rats
and
rabbits
or
the
2­
generation
reproduction
study
in
rats.
However,
there
is
a
concern
for
developing
offspring
because
of
the
effects
of
inorganic
chlorate
on
thyroid
function
in
rats.
The
thyroid
hormone
system
plays
a
critical
role
in
development,
and
it
is
therefore
important
to
understand
whether
the
thyroid
hormone
system
in
the
developing
young
differs
in
response
to
thyroid
toxicants
compared
to
adults.
There
exists,
therefore,
an
uncertainty
regarding
information
on
comparative
thyroid
response
in
young
versus
(
vs.)
adult
rats;
however,
a
SF
reflecting
the
uncertainty
in
comparative
response
is
not
necessary
and
the
10x
FQPA
SF
can
be
removed
(
reduced
to
1x).

The
rationale
for
removal
of
the
FQPA
SF
lies
in
the
comparative
thyroid
physiology
of
rats
vs.
humans.
As
a
consequence
of
these
dynamic
differences,
rats
are
much
more
sensitive
to
thyroid
toxicants,
such
as
chlorate,
than
humans
and
non­
human
primates.
As
discussed
in
the
section
below,
the
chronic
reference
dose
(
RfD)
for
inorganic
chlorates
is
0.03
mg/
kg/
day
based
on
thyroid
hypertrophy
in
adult
rats.
There
is
a
study
of
the
effects
of
chlorate
on
adult
monkeys,
in
which
the
no
observed
adverse
effects
level
(
NOAEL)
for
effects
on
blood
thyroxine
levels
8
was
58
mg/
kg/
day.
If
the
NOAEL
from
the
monkey
study
were
used
to
derive
a
chronic
RfD
with
uncertainty
factors
of
10x
for
interspecies
extrapolation
and
10X
for
intraspecies
variability,
and
an
FQPA
SF
of
10x
reflecting
uncertainties
in
effects
to
the
young,
the
chronic
RfD
would
be
0.06
mg/
kg/
day.
The
chronic
RfD
selected
by
the
risk
assessment
team
of
0.03
mg/
kg/
day
derived
from
a
chronic
rat
study,
conducted
by
the
National
Toxicology
Program
(
NTP),
is
therefore
protective
of
thyroid
effects
in
primates
(
including
a
10X
factor
for
uncertainty
with
respect
to
developing
young)
without
the
necessity
of
an
additional
uncertainty
factor
applied
to
the
rat
data.

In
addition,
the
moderately
refined
dietary
food
assessment
uses
field
trial
data
and
percent
crop
treated
estimates
for
all
commodities,
and
the
residential
exposure
assessment
is
based
on
reliable
data;
as
such,
exposure
will
not
be
underestimated.
The
dietary
drinking
water
assessment
uses
residues
in
finished
drinking
water
collected
from
water
treatment
facilities,
which
use
chlorine
dioxide
or
hypochlorite
to
treat
drinking
water.
See
Revised
Inorganic
Chlorates.
HED
Chapter
of
the
Reregistration
Eligibility
Decision
Document
(
RED)
dated
January
26,
2006,
for
additional
details.

c.
Toxicological
Endpoints
The
toxicological
endpoints
used
in
the
human
health
risk
assessment
for
sodium
chlorate
are
listed
in
Table
2
below.
Although
several
studies
were
considered,
an
acute
reference
dose
(
aRfD)
was
not
identified.
None
of
the
available
studies
provided
an
endpoint
of
toxicity
attributable
to
a
single
exposure.

Sodium
chlorate
is
unlikely
to
be
absorbed
by
the
skin
based
on
its
high
water
solubility
and
ionic
nature;
therefore,
a
risk
assessment
for
dermal
exposure
is
not
needed
and
a
dermal
endpoint
was
not
selected.
For
inhalation
absorption,
a
default
factor
of
100%
was
used
since,
per
Agency
policy,
the
inhalation
dose
was
derived
from
an
oral
endpoint.

The
usual
interspecies
uncertainty
factor
is
10x,
but
there
are
several
important
quantitative
dynamic
differences
between
rats
and
humans
with
respect
to
thyroid
function
that
permit
an
interspecies
factor
of
less
than
10x
for
a
thyroid
toxicant
like
sodium
chlorate.
The
half­
life
of
thyroid
hormone
T4
in
rats
is
approximately
12
hours,
whereas
in
humans,
the
halflife
is
5­
9
days.
The
shorter
half­
life
in
rats
is
likely
related
to
a
high­
affinity
binding
globulin
for
thyroxin
that
is
present
in
humans,
but
absent
in
rodents.
In
the
absence
of
a
functional
thyroid
gland,
a
rat
requires
approximately
10­
times
more
T4
than
an
adult
human
for
full
reconstitution.
Constitutive
thyroid
stimulating
hormone
(
TSH)
levels
are
nearly
25­
times
higher
in
rats
than
in
humans,
reflecting
the
increased
activity
of
the
thyroid­
pituitary
axis
in
rats.
Therefore,
the
10x
interspecies
factor
can
be
reduced
to
3x
based
on
dynamic
considerations.
The
uncertainty
factors
(
UF)
and
safety
factors
used
to
account
for
interspecies
extrapolation,
intraspecies
variability,
and
susceptibility
of
infants
and
children
(
FQPA
SF)
are
also
described
in
Table
2.
9
Table
2.
Summary
of
Toxicological
Doses
and
Endpoints
for
Chlorate
per
se
for
Use
in
Human
Risk
Assessments
for
Inorganic
Chlorates
Exposure
Scenario
Dose,
Uncertainty
Factors
FQPA
Safety
Factor
and
Level
of
Concern
Study
and
Endpoint
for
Risk
Assessment
Acute
Dietary
Acute
RfD=
not
applicable
Although
several
studies
were
considered,
an
acute
reference
dose
(
aRfD)
was
not
identified.
None
of
the
available
studies
provided
an
endpoint
of
toxicity
attributable
to
a
single
exposure.

Chronic
Dietary
(
all
populations)
BMDL1
=
0.9
mg/
kg/
day
UF
=
30
(
3x
interspecies
and
10x
intraspecies)

Chronic
RfD
=
0.03
mg/
kg/
day
FQPA
SF
=
1X
cPAD
=
Chronic
RfD
FQPA
SF
cPAD=
0.03
mg/
kg/
day
Chronic
Study
in
rats
(
NTP,
2004).
The
LOAEL=
5
mg/
kg/
day
based
on
increased
thyroid
gland
follicular
cell
hypertrophy
and
follicular
cell
mineralization.

Short­
and
Intermediate­
Term
Incidental
Oral
Oral
NOAEL
=
30
mg/
kg/
day
UF
=
100
FQPA
SF
=
1X
Residential
LOC
for
MOE
=
100
Subchronic
study
in
rats
McCauley
et
al,
1995.
Pituitary
effects
(
vacuolization)
and
thyroid
gland
effects
(
colloid
depletion),
body
weight
decrease
and
organ
weight
changes
and
reduction
in
erythrocyte
counts
and
hemoglobin
content
at
the
LOAEL
of
100
and
150
mg/
kg/
day
in
males
and
females,
respectively
Short­,
Intermediate­,
and
Long­
Term
Dermal
Not
applicable
Dermal
absorption
is
unlikely
due
to
the
ionic
nature
and
water
solubility
of
sodium
chlorate
Short­,
Intermediate­,
and
Long­
Term
Inhalation
NOAEL
=
30
mg/
kg/
day2
UF
=
100
FQPA
SF
=
1X
Residential
LOC
for
MOE
=
100
Occupational
LOC
for
MOE
=
100
McCauley
et
al,
1995
Cancer
(
Oral,
dermal,
inhalation)
Classification:
Not
likely
to
be
carcinogenic
to
humans
at
doses
that
do
not
alter
thyroid
hormone
homeostasis.

UF
=
uncertainty
factor,
FQPA
SF
=
FQPA
safety
factor,
NOAEL
=
no
observed
adverse
effect
level,
LOAEL
=
lowest
observed
adverse
effect
level,
PAD
=
population
adjusted
dose
(
a
=
acute,
c
=
chronic),
RfD
=
reference
dose,
MOE
=
margin
of
exposure,
LOC
=
level
of
concern,
NA
=
Not
Applicable
1.
A
NOAEL
was
not
identified
in
this
study.
Therefore
a
bench
mark
dose
(
BMD)
analysis
was
performed
and
a
BMDL
of
28
mg
sodium
chlorate/
L
(
22
mg
chlorate/
L)
was
calculated.
This
corresponds
to
0.9
mg
chlorate/
kg/
day
oral
dose.
2.
A
100%
inhalation
absorption
factor
is
used
for
extrapolating
from
an
oral
endpoint
of
toxicity.

2.
Carcinogenicity
of
Sodium
Chlorate
Sodium
chlorate
is
a
thyroid
toxicant
producing
thyroid
gland
follicular
cell
hypertrophy
in
rats
and
mice
following
chronic
exposures.
The
Agency
classified
sodium
chlorate
as
not
likely
to
be
carcinogenic
to
humans
at
doses
that
do
not
alter
thyroid
hormone
homeostasis
in
accordance
with
the
EPA
policy,
Assessment
of
Thyroid
Follicular
Cell
Tumors,
dated
March
10
1998.
This
policy
states
that
nonmutagenic
pesticides
that
induce
elevated
levels
of
TSH
and
thyroid
follicular
cell
tumors
in
the
rat
are
classified
as
not
likely
to
be
carcinogenic
to
humans
at
doses
that
do
not
alter
thyroid
hormone
homeostasis.

The
preliminary
results
of
a
draft
2­
year
National
Toxicology
Program
(
NTP)
bioassay
study
on
sodium
chlorate
to
determine
the
potential
of
this
chemical
to
induce
tumors
in
laboratory
animals
(
rats
and
mice)
(
NTP,
2004)
showed
evidence
of
thyroid
gland
follicular
cell
hyperplasia
and
follicular
cell
tumors
in
male
rats.
The
effects
may
be
attributed
to
changes
in
levels
of
thyroid
hormones
seen
after
administration
of
high
doses
of
sodium
chlorate.
A
final
study
report
is
expected
later
this
year.
In
female
mice
there
was
equivocal
and
marginal
evidence
of
increased
pancreatic
islet
carcinoma.
Sodium
chlorate
was
negative
in
most
bacterial
gene
mutation
assays
and
in
several
cytogenetics
tests,
including
a
hypoxanthineguanine
phosphoribosyl­
transferase
(
HGPRT)
assay
in
Chinese
hamster
ovaries
and
a
micronucleus
assay.

The
Agency
selected
a
chronic
endpoint
based
on
the
thyroid
effects
from
the
NTP
bioassay
study
using
a
benchmark
dose
analysis
approximation
of
the
NOAEL.
This
endpoint
is
protective
for
all
populations,
including
children
because
children
are
not
expected
to
be
more
susceptible
to
chlorate­
induced
thyroid
effects
than
adults.
Therefore,
the
current
chronic
risk
assessments
presented
in
this
document
are
protective
of
any
cancer­
related
effects
for
all
populations.
For
more
information,
see
the
document
Revised
Inorganic
Chlorates.
HED
Chapter
of
the
Reregistration
Eligibility
Decision
Document
(
RED)
dated
January
26,
2006.

3.
Sodium
Chlorate
Endocrine
Effects
The
EPA
is
required
under
the
FFDCA,
as
amended
by
FQPA,
to
develop
a
screening
program
to
determine
whether
certain
substances
(
including
pesticides
active
and
other
ingredients)
"
may
have
an
effect
in
humans
similar
to
an
effect
produced
by
a
naturally
occurring
estrogen,
or
other
such
endocrine
effects
as
the
Administrator
may
designate."
Following
recommendations
of
its
Endocrine
Disruptor
and
Testing
Advisory
Committee
(
EDSTAC),
EPA
determined
that
there
was
a
scientific
basis
for
including,
as
part
of
the
program,
the
androgen
and
thyroid
hormone
systems,
in
addition
to
the
estrogen
hormone
system.

The
available
toxicity
studies
on
sodium
chlorate
demonstrate
the
thyroid
gland
to
be
its
target
of
toxicity.
The
endpoints
selected
to
assess
chronic
dietary
risk
and
short­
and
intermediate­
term
oral
and
inhalation
risks
in
this
document
are
protective
of
the
observed
thyroid
effects
seen
in
the
available
toxicity
studies.
When
additional
appropriate
screening
and/
or
testing
protocols
being
considered
under
the
Agency's
Endocrine
Screening
Disruption
Program
have
been
developed,
sodium
chlorate
may
be
subject
to
further
screening
and/
or
testing
to
better
characterize
effects
related
to
endocrine
disruption.

4.
Metabolites
and
Degradates
The
Agency
reviewed
the
metabolism
of
the
inorganic
chlorates,
and
concluded
that
there
are
several
residues
of
concern
in
food.
In
plants,
the
terminal
residues
of
sodium
chlorate
in/
on
plants
are
likely
chlorate
(
ClO3
­),
chlorite
(
ClO2
­),
and
chloride
(
Cl­).
Based
on
published
rat
metabolism
data,
11
terminal
residues
of
sodium
chlorate
in
animal
tissues
are
also
expected
to
be
chlorate
(
ClO3
­),
chlorite
(
ClO2
­),
and
chloride
(
Cl­).

In
the
environment,
because
chlorate
is
a
strong
oxidizing
agent
(
oxidation
state
V),
it
gets
reduced
to
chlorine
species
in
lower
oxidation
states,
such
as
the
oxyanions
chlorite
(
ClO2
­,
oxidation
state
III)
and
hypochlorite
(
ClO­,
oxidation
state
I),
chlorine
dioxide
(
oxidation
state
IV),
and
chloride
(
oxidation
state
­
I).
Thus,
at
least
some,
and
possibly
a
substantial,
reduction
of
the
chlorate
resulting
from
the
application
of
sodium
chlorate
is
likely
to
occur
in
the
field
prior
to
any
runoff
to
surface
water.
Under
environmental
(
terrestrial
field)
redox
conditions,
and
based
on
chemical
equilibria
alone,
the
thermodynamically
favored,
end
reduction
product
of
chlorate
in
soil
and
in
water
is
the
chloride
anion.
Any
intermediate
chlorine
dioxide
that
may
form
under
environmental
conditions
will
undergo
photochemical
reactions
when
exposed
to
sunlight.
The
chlorine
oxyanions,
chlorite
and
hypochlorite
(
other
possible
more
reduced
intermediates
in
the
ultimate
reduction
of
chlorate
to
chloride),
are
strong
oxidizers
in
themselves;
thus,
they
are
also
reduced
and/
or
undergo
disproportionation
reactions.
Although
reduction
reactions
of
chlorate,
chlorite,
and
hypochlorite
are
said
to
occur
very
fast,
how
fast
they
occur
is
not
known
(
i.
e.,
the
actual
rate
constants
in
the
environment
are
not
known).
Therefore,
at
any
given
time
the
distribution
of
reduced
species
(
type
and
concentration)
cannot
be
estimated.
However,
it
is
unlikely
that
a
single
reduced
species
would
be
present.
Chlorite
is
being
considered
in
the
chlorite/
chlorine
dioxide
reregistration
eligibility
decision
(
case
number
4043).
(
See
Revised
Inorganic
Chlorates.
HED
Chapter
of
the
Reregistration
Eligibility
Decision
Document
(
RED)
dated
January
26,
2006,
for
additional
details.)

5.
Dietary
Exposure
and
Risk
(
Food)

Dietary
exposure
(
food
only)
to
inorganic
chlorates
as
the
chlorate
ion
(
ClO3
­)
may
be
expected
from
the
following
dietary
exposure
routes:
1)
from
sodium
chlorate
as
an
active
ingredient
in
conventional
(
agricultural)
pesticides
used
on
food
crops;
2)
from
sodium
chlorate
and
potassium
chlorate
as
inert
ingredients
in
conventional
pesticides
used
on
food
crops
or
in
poultry
premises;
3)
from
secondary
residues
in
meat/
milk/
poultry/
eggs
due
to
residues
in
animal
feedstuffs;
4)
from
sodium
chlorate
and
calcium
chlorate
as
inert
ingredients
in
antimicrobial
agents
used
as
fruit,
vegetable,
and
egg
sanitizing
washes,
as
treatments
to
mushrooms
to
control
bacterial
blotch,
as
treatments
to
seed
used
for
sprouting,
for
conditioning
live
oysters,
in
poultry
drinking
water,
in
fish
filleting,
and
in
pecan
cracking/
dyeing;
and
5)
as
a
potential
redox
of
chlorine
dioxide
and
sodium
chlorite
in
conventional
and
antimicrobial
pesticides;
(
6)
from
degradation
of
hypochlorites
in
antimicrobial
agents
used
as
fruit
and
vegetable
washes;
and,
(
7)
from
translocation
of
very
small
amounts
of
chlorate
ion
(
ClO3
­)
by
plants
(
translocation
of
significant
amounts
would
be
phytotoxic
to
plants)
from
the
environment
which
may
be
present
as
a
result
of
inorganic
chlorate
pesticide
uses.

No
acute
dietary
endpoint
was
selected
because
effects
attributable
to
a
single
dose
were
not
seen
in
the
available
data.
Chronic
and
cancer
dietary
analyses
were
conducted
for
the
general
U.
S.
population
and
various
population
subgroups.

a.
Exposure
Assumptions
A
chronic
dietary
risk
assessment
was
conducted
using
the
Dietary
Exposure
Evaluation
12
Model
software
with
the
Food
Commodity
Intake
Database
(
DEEM­
FCID
 
,
Version
2.03),
which
uses
food
consumption
data
from
the
USDA's
Continuing
Surveys
of
Food
Intakes
by
Individuals
(
CSFII)
from
1994­
1996
and
1998.
No
food
monitoring
data
are
available
for
this
risk
assessment;
therefore,
exposure
estimates
in
food
were
based
on
field
trial
data
or,
in
the
case
of
fruit/
vegetable/
other
washes,
were
derived
from
a
film
thickness
model.
No
chemicalspecific
livestock
metabolism
or
feeding
data
are
available;
exposure
estimates
in
meat,
milk,
poultry,
and
eggs
were
derived
from
rat
metabolism
data,
field
trial
data,
and
livestock
reference
information
concerning
feed
consumption,
tissue
weights,
and
milk
production.
Default
concentration
factors
(
no
chemical­
specific
processing
data
are
available)
and
the
effects
of
washing
after
foliar
treatments
were
also
incorporated
into
the
risk
assessment.
Percent
crop
treated
data
were
used
in
this
analysis.
Exposures
were
single
point
estimates;
no
residue
decline
was
utilized.

b.
Population
Adjusted
Dose
A
population
adjusted
dose,
or
PAD,
is
the
reference
dose
(
RfD)
adjusted
for
the
FQPA
SF.
A
risk
estimate
that
is
less
than
100%
of
the
acute
PAD
(
aPAD),
the
dose
at
which
an
individual
could
be
exposed
over
the
course
of
a
single
day
and
no
adverse
health
effects
would
be
expected,
does
not
exceed
EPA's
level
of
concern.
Likewise,
a
risk
estimate
that
is
less
than
100%
of
the
chronic
PAD
(
cPAD),
the
dose
at
which
an
individual
could
be
exposed
over
the
course
of
a
lifetime
and
no
adverse
health
effects
would
be
expected,
does
not
exceed
EPA's
level
of
concern.
c.
Acute
Dietary
Risk
(
Food)

No
acute
dietary
endpoint
was
selected
because
effects
attributable
to
a
single
dose
were
not
seen
in
the
available
data;
therefore,
an
acute
dietary
risk
assessment
was
not
conducted.

d.
Chronic
Dietary
Risk
(
Food)

A
chronic
(
non­
cancer)
dietary
risk
assessment
was
conducted
for
all
potential
chlorate
dietary
exposure
routes
using
food
consumption
data
from
1994­
1996
and
1998.
The
chronic
dietary
exposure
and
risk
estimates
resulting
from
food
intake
were
determined
for
the
general
U.
S.
population
and
various
population
subgroups.

The
chronic
(
non­
cancer)
dietary
(
food
only)
risk
is
below
the
Agency's
level
of
concern
for
the
general
US
population
and
all
population
subgroups.
The
most
likely
highest
exposed
population
subgroup,
children
1­
2
years
of
age,
was
at
28%
of
the
cPAD.
See
Table
3
below
for
details.

Table
3.
Results
of
Chronic
Dietary
(
Food
only)
Exposure
Analysis
Population
Subgroup
cPAD
(
mg/
kg/
day)
Exposure
(
mg/
kg/
day)
%
cPAD
All
populations
0.002730
9
All
infants
(<
1
year
old)
0.03
0.004511
15
13
Table
3.
Results
of
Chronic
Dietary
(
Food
only)
Exposure
Analysis
Children
1­
2
years
old
0.008376
28
Children
3­
5
years
old
0.006906
23
A
cancer
dietary
risk
assessment
was
conducted
for
all
potential
chlorate
dietary
exposure
routes,
using
the
same
dietary
(
food
only)
exposure
estimates
used
in
the
chronic
(
non­
cancer)
dietary
risk
assessment
for
the
US
population.
As
discussed
above,
sodium
chlorate
is
a
thyroid
toxicant
producing
thyroid
gland
follicular
cell
hypertrophy
in
rats
and
mice
following
chronic
exposures,
and
may
be
producing
follicular
cell
tumors
in
rats.
The
lack
of
mutagenicity
indicates
that
the
thyroid
tumors
are
induced
by
a
non­
mutagenic
mechanism.
Children
are
not
expected
to
be
more
susceptible
to
chlorate­
induced
thyroid
effects
than
adults,
and
the
endpoint
selected
for
the
thyroid
effects
is
protective
for
all
populations,
including
children.
Therefore,
as
shown
in
Table
3
above,
the
chronic
(
food
only)
dietary
risk
assessment
is
protective
for
cancer
for
the
general
US
population,
since
the
estimated
risk
does
not
exceed
100%
of
the
cPAD.

6.
Dietary
Exposure
and
Risks
(
Drinking
Water)

Drinking
water
exposure
to
pesticides
can
occur
through
surface
and
groundwater
contamination.
Chronic
dietary
(
water
only)
risk
assessments
were
conducted
using
DEEMFCID
 
Version
2.03
and
drinking
water
consumption
data
from
the
USDA's
CSFII
from
1994­
1996
and
1998.
Exposures
were
single
point
estimates;
no
residue
decline
was
utilized.

Drinking
water
exposure
can
result
from
several
different
uses
for
sodium
chlorate.
Agriculturally,
sodium
chlorate
is
used
as
a
defoliant
and
dessicant,
primarily
on
cotton;
however,
it
is
also
applied
to
a
wide
variety
of
other
crops
including,
but
not
limited
to,
rice,
corn,
soybeans,
dry
beans,
potatoes,
sunflowers,
flax,
safflower,
chili
peppers
(
for
processing
only),
grain
sorghum,
and
wheat.
As
a
non­
selective
herbicide,
it
is
applied
to
industrial/
noncrop
areas
such
as
rights­
of­
ways,
building
perimeters,
ditch
banks,
bleachers,
airport
runways,
vacant
lots,
fire
hydrants,
or
as
a
pre­
paving
treatment.
Sodium
chlorate
is
also
used
to
generate
chlorine
dioxide,
which
is
then
used
to
bleach
wood
pulp/
paper
and,
in
some
cases,
treat
drinking
water.
All
of
these
uses
could
result
in
chlorate
reaching
water
systems.
However,
the
majority
of
chlorate
in
drinking
water
is
a
result
of
drinking
water
disinfection
treatment
practices.

In
the
US,
there
are
two
primary
methods
of
drinking
water
treatment.
The
first
method
is
the
generation
of
chlorine
dioxide.
In
the
second
method,
either
gaseous
chlorine
or
hypochlorite
is
used
to
produce
free
chlorine.
Each
of
these
methods,
except
the
use
of
gaseous
chlorine,
produce
chlorate
as
a
disinfection
byproduct
(
DBP).
The
American
Water
Works
Association
(
AWWA)
Disinfection
Systems
Committee
tracks
disinfection
practices
in
US
community
water
systems.
AWWA's
most
recent
comprehensive
survey
(
completed
in
1998)
estimated
that,
of
all
community
water
systems
(
CWS),
approximately
20%
of
CWSs
serving
populations
greater
than
10,000
use
sodium
hypochlorite
(
2%
generated
it
on­
site),
8%
use
chlorine
dioxide,
and
<
1%
use
calcium
hypochlorite.
For
CWSs
using
groundwater
and
serving
populations
less
than
10,000,
the
survey
estimated
that
approximately
34%
use
sodium
hypochlorite,
none
use
chlorine
dioxide,
and
at
least
4.5%
use
calcium
hypochlorite.
For
CWSs
14
using
surface
water
and
serving
less
than
10,000,
the
survey
estimated
that
17%
use
sodium
hypochlorite,
6%
use
chlorine
dioxide,
and
9%
use
calcium
hypochlorite.

For
chlorine
dioxide
generation,
both
sodium
chlorate
and
sodium
chlorite
are
used
as
precursor
materials,
and
both
typically
result
in
chlorate
byproduct
in
finished
drinking
water.
Sodium
chlorite
is
more
commonly
used
than
sodium
chlorate.
The
free
chlorine
disinfection
process
involves
the
use
of
either
gaseous
chlorine,
or
sodium
or
calcium
hypochlorite,
as
precursor
materials.
Historically,
gaseous
chlorine
has
far
more
widely
been
used
than
hypochlorite
to
produce
free
chlorine.
In
recent
years,
primarily
as
a
result
of
various
homeland
security
measures,
many
drinking
water
systems
are
switching
from
gaseous
chlorine
to
hypochlorite.
While
the
use
of
gaseous
chlorine
does
not
result
in
chlorate
byproduct
in
finished
drinking
water,
the
use
of
either
sodium
or
calcium
hypochlorite
can
produce
chlorate
byproduct,
and
this
will
be
discussed
in
greater
detail
later
in
this
section.

Chlorine
Dioxide
The
use
of
chlorine
dioxide
can
introduce
chlorate
into
the
finished
water
by
several
routes.
Drinking
water
plants
generally
use
sodium
chlorite
as
a
starting
material
(
i.
e.,
feedstock)
in
the
production
of
chlorine
dioxide.
Chlorate
ion
may
be
present
as
a
contaminant
in
the
sodium
chlorite
feedstock
(
usually
less
than
four
percent
of
the
active
chlorite
is
chlorate).
A
typical
range
of
chlorate
carryover
to
the
finished
water
from
chlorite
feedstock
contamination
is
about
50
µ
g/
L
for
a
1
mg/
L
dose
of
chlorine
dioxide.
Technology
to
generate
chlorine
dioxide
using
sodium
chlorate
is
now
available
to
the
drinking
water
industry,
which
introduces
the
possibility
of
chlorate
carryover
to
the
finished
water
from
the
chlorate
feedstock.
However,
since
this
method
is
more
technically
complicated
than
the
method
used
with
sodium
chlorite,
sodium
chlorite
is
far
more
commonly
used
in
the
generation
of
chlorine
dioxide
than
sodium
chlorate.

Chlorate
ion
(
ClO3
­)
may
also
be
produced
due
to
inefficient
generation
of
chlorine
dioxide.
Excess
chlorine
will
favor
the
production
of
chlorate
over
chlorine
dioxide,
as
will
keeping
the
generator
mixtures
at
highly
alkaline
(
pH
>
11)
or
acidic
(
pH
<
3)
conditions.
If
the
concentrations
of
feedstock
reactants
are
too
low,
or
too
much
dilution
water
is
added
during
the
reaction,
chlorate
formation
is
also
favored.

Chlorite
ion
(
ClO2
­)
is
a
major
degradation
product
resulting
from
the
reaction
of
chlorine
dioxide
with
inorganic
and
organic
constituents
in
the
water.
When
free
chlorine
is
used
after
the
application
of
chlorine
dioxide
in
the
treatment
process,
chlorite
is
oxidized
to
chlorate.
This
conversion
will
continue
over
time
as
the
water
travels
through
the
distribution
system.
Chlorate
ion
is
also
formed
by
photodecomposition
of
chlorine
dioxide
when
treated
water
is
exposed
to
bright
sunlight
in
open
basins.

There
are
ways
that
water
systems
can
control
the
levels
of
chlorate
in
drinking
water,
and
these
will
be
discussed
in
Section
4
of
this
document.
15
Hypochlorite
Chlorine­
based
disinfectants,
such
as
free
chlorine,
are
also
used
by
drinking
water
treatment
systems
to
treat
drinking
water.
Some
of
these
water
systems
use
sodium
hypochlorite
or
calcium
hypochlorite
as
their
source
of
free
chlorine.
Chlorate
ion
can
be
formed
in
these
products
during
the
manufacturing
process,
but
the
decomposition
of
hypochlorite
solutions
during
storage
is
the
more
significant
source
of
chlorate
ion
in
systems
using
hypochlorite.

Chlorate
ion
concentrations
increase
between
the
time
of
manufacture
and
delivery
to
the
water
plant.
The
rate
at
which
hypochlorite
ion
disproportionates
to
chlorate
is
influenced
by
concentration
of
hypochlorite,
pH,
and
temperature.
As
with
the
chlorine
dioxide
methods,
there
are
several
ways
that
water
systems
using
hypochlorite
can
control
the
levels
of
chlorate;
these
will
be
discussed
in
Section
4
of
this
document.

a.
Drinking
Water
Exposure
Data
on
the
occurrence
of
chlorate
ion
in
drinking
water
were
available
from
two
primary
sources:
1)
the
Information
Collection
Rule
(
ICR)
Auxiliary
1
Database,
Version
5.0,
and
2)
the
American
Water
Works
Association
Research
Foundation
(
AwwaRF)
study
on
the
control
of
chlorate
ion
in
hypochlorite
solutions.
The
ICR
data
is
the
more
extensive
data
set,
and
the
water
systems
represented
in
the
ICR
database
serve
60%
of
the
total
US
population.
The
EPA
Office
of
Water
(
OW)
issued
the
ICR
in
order
to
collect
data
to
support
future
regulation
of
microbial
contaminants,
disinfectants,
and
disinfection
byproducts.
Monitoring
for
chlorate
was
included
in
the
ICR,
since
chlorate
is
a
disinfection
byproduct.
Source
water
and
drinking
water
were
monitored
for
chlorate
ion
between
July
1997
and
December
1998.
Water
systems
serving
a
population
of
at
least
100,000
were
required
to
monitor
for
chlorate
ion
at
treatment
plants
using
chlorine
dioxide
or
hypochlorite
solutions
in
the
treatment
process.
Plants
using
chlorine
dioxide
collected
monthly
samples
of
the
source
water
entering
the
plant,
the
finished
water
leaving
the
plant,
and
at
three
sample
points
in
the
distribution
system
(
near
the
first
customer,
an
average
residence
time,
and
a
maximum
residence
time).
Plants
using
hypochlorite
solutions
were
required
to
collect
quarterly
samples
of
the
water
entering
and
leaving
the
plant.
If
chlorine
dioxide
or
hypochlorite
solutions
were
used
intermittently
at
a
plant,
chlorate
ion
samples
were
only
required
in
sample
periods
in
which
they
were
in
use.

The
ICR
Database
was
considered
the
more
appropriate
data
source
for
estimating
average
chlorate
concentrations
in
drinking
water
from
individual
water
treatment
plants.
The
AwwaRF
study
is
a
less
robust
data
set,
consisting
of
only
one
sample
per
utility,
whereas
the
ICR
database
included
multiple
samples
over
an
18
month
period.
Both
the
AwwaRF
study
and
the
ICR
data
reveal
high
concentrations
of
chlorate
ion
to
be
a
local
problem
affecting
a
relatively
small
number
of
systems.

Based
on
the
ICR
monitoring
data,
the
Agency
was
able
to
assess
exposure
to
chlorate
in
drinking
water.
The
ICR
data
confirm
the
presence
of
chlorate
in
untreated
source
water
which
may
be
the
result
of
agricultural
and
other
uses
of
sodium
chlorate.
However,
the
chlorate
concentrations
in
ambient
water
are
generally
very
low
and
are
minor
compared
to
those
observed
in
drinking
water
treated
with
chlorine
dioxide
or
hypochlorite.
Table
4
below
16
summarizes
the
annual
chlorate
concentrations
calculated
for
each
plant.
The
data
listed
for
hypochlorite
plants
is
the
average
chlorate
concentrations,
taken
from
samples
collected
at
the
entry
point
to
a
distribution
system.
The
figures
for
chlorine
dioxide
in
the
next
two
columns
(
chlorine
dioxide
plans
and
combined
hypochlorite
and
chlorine
dioxide
plants)
represent
the
distribution
system
average
chlorate
concentrations.
As
previously
explained,
for
chlorine
dioxide
plants,
samples
were
collected
from
three
points
in
the
distribution
systems;
the
data
from
these
three
collection
points
were
used
to
calculate
a
distribution
system
average.
Monitoring
in
the
distribution
system
was
required
by
the
ICR,
since
chlorate
concentrations
are
expected
to
change
as
the
water
travels
through
the
distribution
system.
The
concentration
changes,
because
many
of
the
chlorine
dioxide
systems
use
chlorine
to
maintain
a
disinfectant
residual
in
the
distribution
system,
and
chlorine
reacts
with
the
chlorite
ion
to
form
chlorate
ion.

Table
4.
Distribution
of
Average
Annual
Chlorate
Concentrations
­
ICR
Data
Hypochlorite
Plantsa
Chlorine
Dioxide
Plants
b
Combined
Hypochlorite
and
Chlorine
Dioxide
Plants
Number
of
Public
Water
Systems
44
22
66
Number
of
Water
Treatment
Plants
61
29
90
Chlorate
Concentration
(
µ
g/
L)

10th
Percentile
23
52
24
20th
Percentile
37
79
53
50th
Percentile
(
Median)
99
129
108
80th
Percentile
155
217
179
90th
Percentile
239
264
242
Maximum
502
691
691
a.
Concentrations
for
hypochlorite
plants
are
an
average
of
samples
collected
from
distribution
system
entry
points.
b.
For
chlorine
dioxide
pants,
the
distribution
system
average
concentration
was
calculated
for
each
WTP
using
the
three
distribution
system
sample
points.

b.
Acute
Dietary
Risk
(
Drinking
Water)

No
acute
dietary
endpoint
was
selected
because
effects
attributable
to
a
single
dose
were
not
seen
in
the
available
data;
therefore,
an
acute
dietary
(
drinking
water
only)
risk
assessment
was
not
conducted.

c.
Chronic
Dietary
Risk
(
Drinking
Water)

The
chronic
dietary
(
water
only)
risk
assessment
for
chlorate
in
drinking
water,
using
the
highest
annual
average
concentration
estimated
at
0.69
mg/
L,
is
below
100%
of
the
cPAD,
and
therefore,
is
below
the
Agency's
level
of
concern
for
the
general
US
population
and
all
population
subgroups
except
infants
(<
1
year
of
age).
The
highest
exposed
subgroup,
infants,
was
159%
of
the
cPAD,
based
on
the
highest
annual
average
concentration
of
chlorate
in
Table
4
(
0.69
mg/
L).
Using
the
90th
percentile
annual
average
concentration
estimated
at
0.24
mg/
L,
the
chronic
(
non­
cancer)
dietary
(
water
only)
risk
for
infants
was
55%
of
the
cPAD.
Also
for
infants,
using
the
median
annual
average
concentration
estimated
at
0.11mg/
L,
the
risk
was
25%
17
of
the
cPAD.
See
Table
5
below
for
details.

Table
5.
Sum
Table
5.
Summary
of
Estimated
Chronic
Dietary
(
water
only)
Exposure
and
Risk
for
Sodium
Chlorate
by
Average
Annual
Concentration
in
Large
Drinking
Water
Systems
%
cPAD
Population
Subgroup
cPAD
mg/
kg/
day
Water
Estimated
at
the
Highest
Annual
Average
(
0.69
mg/
L)
Water
Estimated
at
the
90th
Percentile
Annual
Average
(
0.24
mg/
L)
Water
Estimated
at
the
Median
Annual
Average
(
0.11
mg/
L)

General
U.
S.
Population
49
17
8
All
Infants
(<
1
yr)
159
55
25
Children
1­
2
yrs
72
25
12
Children
3­
5
yrs
67
23
11
Children
6­
12
yrs
47
16
7
Youth
13­
19
yrs
35
12
6
Adults
20­
49
yrs
45
16
7
Adults
50+
yrs
48
17
8
Females
13­
49
yrs
0.03
45
16
7
7.
Residential
Exposure
and
Risk
Residential
exposure
assessments
consider
all
potential
non­
occupational
pesticide
exposure,
other
than
exposure
due
to
residues
in
foods
or
in
drinking
water.
For
sodium
chlorate,
the
Agency
has
evaluated
potential
exposure
and
risk
to
sodium
chlorate
for
homeowners
who
handle
(
mix,
load,
and
apply)
products
containing
sodium
chlorate.
The
Agency
also
evaluated
potential
post­
application
exposure
and
risk
to
adults
and
children
entering
sodium
chlorate­
treated
areas,
such
as
lawns,
or
patio
areas.
Since
the
episodic
nature
of
residential
exposure
for
sodium
chlorate
is
inconsistent
with
the
mechanism
of
chlorate
carcinogenicity,
a
residential
cancer
risk
assessment
was
not
conducted.

To
estimate
residential
non­
cancer
(
dermal
and
inhalation)
risks,
the
Agency
calculates
a
margin
of
exposure
(
MOE),
which
is
the
ratio
of
the
NOAEL
selected
for
risk
assessment
to
the
exposure.
This
MOE
is
compared
to
a
level
of
concern
which
is
the
same
value
as
the
uncertainty
factor
(
UF)
applied
to
a
particular
toxicity
study.
The
standard
UF
is
100x
(
10x
to
account
for
interspecies
extrapolation
and
10x
for
intraspecies
variation),
plus
any
additional
FQPA
SF
retained
due
to
concerns
unique
to
the
protection
of
infants
and
children.
The
FQPA
SF
for
sodium
chlorate
is
reduced
to1x
for
reasons
explained
above;
thus,
the
Agency's
LOC
is
100.

a.
Residential
Handler
Risks
The
Agency
determined
that
there
is
the
potential
for
residential
handlers
to
be
exposed
to
sodium
chlorate
in
outdoor
residential
settings
during
the
application
of
conventional
pesticide
18
products
containing
sodium
chlorate
as
the
active
ingredient.
Sodium
chlorate
can
be
used
as
a
non­
selective
herbicide
in
outdoor
residential
environments
as
a
spot
treatment
or
edging
treatment
around
patios,
along
fence
lines,
lawn
edges,
around
foundations,
underneath
or
around
wood
decks,
and
in
cracks
and
crevices
of
driveways.
Although
there
is
the
potential
for
dermal
exposure
by
residential
handlers,
sodium
chlorate
is
an
inorganic
salt;
therefore,
significant
absorption
of
sodium
chlorate
through
intact
skin
is
not
expected.
Hence,
only
a
short­
term
risk
assessment
for
residential
handlers
exposed
to
sodium
chlorate
via
the
inhalation
exposure
route
was
conducted.

The
risk
assessment
considered
seven
residential
exposure
scenarios
based
on
the
types
of
equipment
and
techniques
that
can
potentially
be
used
to
make
sodium
chlorate
applications,
such
as
handheld
equipment
(
hand
wand
sprayers)
and
ready­
to­
use
(
RTU)
methods
(
sprinkler
cans).
The
use
patterns
assessed
are
representative
of
the
range
of
sodium
chlorate
residential
uses.

The
Agency
considered
residential
handler
exposure
scenarios
to
be
short­
term
(
1­
30
days)
only
due
to
infrequency
of
use
associated
with
homeowner
products.
The
residential
risk
assessment
is
also
based
on
estimates
of
what
and
how
much
homeowners
would
typically
treat,
such
as
the
size
of
the
lawn
or
garden,
based
on
the
Agency's
standard
operating
procedures
for
residential
exposures.
For
more
information
on
the
daily
volume
handled
and
the
area
treated
used
in
each
residential
handler
scenarios,
refer
to
Inorganic
Chlorates:
Residential
and
Occupational
Exposure
Assessment
for
the
Reregistration
Eligibility
Decision
Document,
dated
January
26,
2006.

Risk
to
homeowners
handling
sodium
chlorate
products
are
below
the
Agency's
LOC.
The
inhalation
MOEs
for
all
scenarios
assessed
are
greater
than
100
(
ranging
from
370
to
710,000).
See
Table
6
for
further
detail.

Table
6.
Sodium
Chlorate
Residential
Risk
Estimates1
Exposure
Scenario
(
Scenario
#)
Daily
Area
Treated
Crop/
Target
Application
Rate
Inhalation
MOE2
Mixing/
loading/
applying
liquids
with
a
low
pressure
hand
wand
sprayer
1000
ft2/
day
Spot/
edging
treatment
23.7
lb
ai/
1000
ft2
3000
Loading/
applying
RTU
liquid
with
a
trigger
pump
sprayer
1
gallon/
day
Spot/
edging
treatment
0.196
lb
ai/
gallon
87000
Mixing/
loading/
applying
liquids
with
a
sprinkler
can
1000
ft2/
day
Spot/
edging
treatment
23.7
lb
ai/
1000
ft2
5200
Applying
liquid
with
a
RTU
sprinkler
can
1
gallon
/
day
Spot/
edging
treatment
0.27
lb
ai/
gallon
710000
Applying
granules
by
hand
1000
ft2/
day
Spot/
edging
treatment
12
lb
ai/
1000
ft2
370
Loading
and
applying
granules
with
a
1000
ft2/
day
Spot/
edging
treatment
12
2800
19
Table
6.
Sodium
Chlorate
Residential
Risk
Estimates1
Exposure
Scenario
(
Scenario
#)
Daily
Area
Treated
Crop/
Target
Application
Rate
Inhalation
MOE2
belly
grinder
lb
ai/
1000
ft2
Loading
and
applying
granules
with
a
push­
type
spreader
1000
ft2/
day
Spot/
edging
treatment
12
lb
ai/
1000
ft2
200000
1.
Residential
exposures
assessments
do
not
include
personal
protective
equipment
(
PPE).
2.
Inhalation
MOE
=
Oral
NOAEL
(
30
mg/
kg/
day)
/
Daily
Inhalation
Dose.
The
LOC
for
MOE
is
100.

b.
Residential
Post­
Application
Risks
The
Agency
uses
the
term
"
post­
application"
to
describe
exposures
to
individuals
that
occur
as
a
result
of
being
in
an
environment
that
has
been
previously
treated
with
a
pesticide.
Unlike
residential
handler
exposure,
where
the
EPA
assumed
only
adults
will
be
handling
and
applying
sodium
chlorate
products,
individuals
of
varying
ages
can
potentially
be
exposed
when
reentering
or
performing
activities
in
areas
that
have
been
previously
treated.
For
products
containing
sodium
chlorate
as
the
active
ingredient,
a
post­
application
exposure
assessment
was
not
conducted
for
the
following
reasons:

 
Although
potential
for
post­
application
dermal
exposure
in
residential
and
occupational
settings
exists,
sodium
chlorate
is
an
inorganic
salt;
therefore,
significant
absorption
of
sodium
chlorate
through
the
skin
is
not
expected.
 
Post­
application
inhalation
exposure
is
not
expected
due
to
a
negligible
vapor
pressure.
 
Post­
application
exposure
assessments
for
residential
settings
(
dermal
and
incidental
oral)
are
not
typically
performed
for
spot
treatments/
edging
treatments.

However,
for
products
containing
sodium
chlorate
as
an
inert
ingredient,
there
is
the
potential
for
post­
application
exposure
in
outdoor
residential
settings
from
entering
areas
previously
treated.
Therefore,
a
residential
post­
application
risk
assessment
was
conducted
based
on
this
use.
As
an
inert
ingredient
in
herbicide
formulations
professionally
broadcast
on
residential
sites,
there
is
potential
for
children
to
have
incidental
oral
exposures
(
i.
e.,
hand­
tomouth
object­
to­
mouth,
and
soil
ingestion).
As
stated
above,
residential
post­
application
exposures
via
dermal
and
inhalation
routes
are
not
of
concern.
Although
there
is
the
potential
for
post­
application
dermal
exposure
in
residential
settings,
sodium
chlorate
is
an
inorganic
salt;
therefore,
significant
dermal
absorption
of
sodium
chlorate
through
intact
skin
is
not
expected.
Post­
application
inhalation
exposure
for
sodium
chlorate
is
not
expected
due
to
negligible
vapor
pressure.

A
series
of
conservative
assumptions
and
exposure
factors
served
as
the
basis
for
completing
the
residential
post­
application
risk
assessment,
and
those
assumptions
and
factors
are
listed
in
detail
in
the
previously
referenced
Inorganic
Chlorates:
Residential
and
Occupational
Exposure
Assessment
for
the
Reregistration
Eligibility
Decision
Document,
dated
January
26,
2006.
The
risk
estimates
for
incidental
oral
exposures
to
sodium
chlorate
as
an
inert
ingredient
in
other
pesticide
formulations
and
the
highest
exposed
population
subgroup
are
20
shown
in
Table
7.
The
combined
oral
MOE
of
23,000
is
greater
than
100;
therefore,
the
risk
is
below
the
Agency's
level
of
concern.

Table
7.
Residential
Post­
application
Risk
Estimates
for
Sodium
Chlorate
as
an
Inert
Ingredient
in
Herbicide
Products
Applied
Professionally
to
Residential
Sites
Population
Subgroup
Scenario
Route
MOE
Combined
MOE
Hand­
to­
Mouth
Oral
29000
Object­
to­
Mouth
Oral
110000
Child
Soil
Ingestion
Oral
8600000
23000
8.
Aggregate
Risk
The
FQPA
amendments
to
the
Federal
Food,
Drug,
and
Cosmetic
Act
(
FFDCA,
Section
408(
b)(
2)(
A)(
ii))
require
"
that
there
is
a
reasonable
certainty
that
no
harm
will
result
from
aggregate
exposure
to
the
pesticide
chemical
residue,
including
all
anticipated
dietary
exposures
and
other
exposures
for
which
there
is
reliable
information."
Aggregate
exposure
will
typically
include
exposures
from
food,
drinking
water,
residential
uses
of
a
pesticide,
and
other
nonoccupational
sources
of
exposure.

In
accordance
with
FQPA,
the
Agency
must
consider
and
aggregate
pesticide
exposures
and
risks
from
three
major
sources:
food,
drinking
water,
and
if
applicable,
residential
or
other
non­
occupational
exposures.
In
an
aggregate
assessment,
exposures
from
relevant
sources
are
added
together
and
compared
to
quantitative
estimates
of
hazard
(
e.
g.,
a
NOAEL),
or
the
risks
themselves
can
be
aggregated.
When
aggregating
exposures
and
risks
from
various
sources,
the
Agency
considers
both
the
route
and
duration
of
exposure.
Aggregate
exposure
and
risk
assessments
for
sodium
chlorate
include
the
following
scenarios:
short­
term
(
food
+
water
+
residential
handler)
and
chronic
dietary
(
food
+
drinking
water).
Results
of
the
aggregate
risk
assessment
are
summarized
here,
and
are
discussed
more
extensively
in
the
document:
Revised
Inorganic
Chlorates.
HED
Chapter
of
the
Reregistration
Eligibility
Decision
Document
(
RED)
dated
January
26,
2006,
which
is
available
in
the
public
docket
and
on
the
internet.

a.
Short­
Term
Aggregate
Risk
(
food
+
drinking
water)

Short­
term
aggregate
risk
was
assessed
for
adults
only,
using
the
highest
exposure
scenario
(
inhalation
exposure
while
applying
granules
by
hand).
Short­
term
aggregate
risk
for
children
would
be
less
than
the
short­
term
aggregate
risk
for
adults
(
MOE
of
324),
because
the
short­
term
MOE
for
residential
risk
to
children
from
the
use
of
sodium
chlorate
as
an
inert
is
significantly
greater
(
i.
e.,
lower
risk)
than
the
residential
handler
short­
term
MOE
for
adults.
Thus,
all
short­
term
aggregate
risks
are
below
the
Agency's
level
of
concern
(
i.
e.,
MOEs
are
greater
than
100),
as
presented
in
Table
8.
21
Table
8.
Short­
Term
Aggregate
Risk
Calculations
Population
Target
Aggregate
MOE
MOE
Food
+
water
MOE
inhalation
Aggregate
MOE
(
food
+
water
+
residential)

Adult
100
1715
400
324
b.
Chronic
Aggregate
Risk
(
food
+
drinking
water)

Since
no
chronic
residential
(
non­
dietary)
exposure
scenarios
have
been
identified,
the
chronic
aggregate
risk
assessment
considers
exposure
only
through
food
and
drinking
water.
To
assess
aggregate
risks
from
chronic
food
and
drinking
water
exposure,
the
Agency
used
conservative
Tier
1
chronic
food
estimates
and
incorporated
drinking
water
monitoring
data
collected
under
the
Information
Collection
Rule
(
ICR).
For
chronic
aggregate
dietary
risks,
using
the
estimated
highest
annual
average
of
drinking
water
concentrations,
food
and
drinking
water
chronic
exposure
estimates
were
above
the
Agency's
level
of
concern
for
all
infants
(<
1
year
old),
the
most
highly
exposed
population,
at
174%
cPAD.
Chronic
aggregate
dietary
risks
were
at
the
Agency's
level
of
concern
(
100
%
cPAD)
for
children
1­
2
years
of
age.
All
other
population
subgroups
were
<
100
%
cPAD,
and
therefore,
below
the
Agency's
level
of
concern.
At
the
90th
percentile
and
median
annual
average
water
concentration,
all
population
subgroups
are
below
the
Agency's
LOC.
The
results
of
this
assessment
for
sodium
chlorate
are
presented
below
in
Table
9.

Table
9.
Summary
of
Chronic
Dietary
Aggregate
(
food
+
drinking
water)
Risk
for
Sodium
Chlorate
%
cPAD
(
food
+
drinking
water)

Population
Subgroupa
cPAD
(
mg/
kg/
day)
Highest
Annual
Average
(
0.69
mg/
L)
90th
Percentile
Annual
Average
(
0.24
mg/
L)
Median
Annual
Average
(
0.11
mg/
L)

General
US
Population
58
26
17
All
Infants
(<
1
yr)
174
70
40
Children
1­
2
yrs
100
53
39
Children
3­
5
yrs
0.03
90
47
34
9.
Occupational
Exposure
and
Risk
The
occupational
risk
assessment
addresses
risks
to
workers
who
may
be
exposed
to
sodium
chlorate
when
mixing,
loading,
or
applying
a
pesticide
(
i.
e.,
handlers),
and
when
entering
treated
sites
for
routine
tasks
(
post­
application).
Please
see
Table
2
for
the
toxicological
endpoints
used
in
the
sodium
chlorate
occupational
assessment.
Based
on
the
registered
use
patterns
of
sodium­
chlorate,
short­
term
(
1­
30
days)
and
intermediate­
term
(
1­
6
months)
occupational
exposures
were
assessed;
long­
term
(>
6
months)
exposure
is
not
expected.
22
Exposure
for
workers
generally
occurs
via
the
dermal
or
inhalation
route;
however,
since
sodium
chlorate
is
an
inorganic
salt,
and
significant
absorption
of
sodium
chlorate
through
the
skin
is
not
expected,
a
dermal
toxicological
endpoint
was
not
selected.
As
such,
a
risk
assessment
for
dermal
exposure
was
not
performed.
Similarly,
post­
application
exposure
was
not
assessed
due
to
the
physical
and
chemical
characteristics
of
sodium
chlorate
as
an
inorganic
salt;
no
significant
amount
of
sodium
chlorate
is
expected
to
be
absorbed
through
the
skin,
and
the
vapor
pressure
is
negligible.
Further,
for
the
antimicrobial
use
of
sodium
chlorate
in
chlorine
dioxide
generation
for
drinking
water
treatment,
exposure
to
chlorate
is
expected
to
be
negligible
because
of
its
conversion
to
chlorine
dioxide
inside
the
closed
generators.
Post­
application
exposure
to
chlorine
dioxide
will
be
addressed
in
the
chlorine
dioxide
risk
assessment
and
RED.

The
occupational
assessment
estimates
non­
cancer
risks
using
the
MOE
approach.
MOEs
greater
than
100
are
below
the
Agency's
level
of
concern
for
short­
and
intermediate­
term
occupational
exposure.

Occupational
exposure
to
sodium
chlorate
was
assessed
using
data
from
the
Pesticide
Handler
Exposure
Database
(
PHED)
and
Outdoor
Residential
Exposure
Task
Force
(
ORETF).
In
addition,
standard
default
assumptions
pertaining
to
average
body
weight,
work
day,
and
area
treated
daily
were
used
to
calculate
risk
estimates.
Application
rates
used
in
this
assessment
are
derived
directly
from
current
sodium
chlorate
labels.
Worker
exposure
and
risk
estimates
are
based
on
the
best
data
currently
available
to
the
Agency.

The
occupational
risk
assessment
is
summarized
here.
For
further
detail,
see
the
following
documents:
(
1)
Revised
Inorganic
Chlorates.
HED
Chapter
of
the
Reregistration
Eligibility
Decision
Document
(
RED)
dated
January
26,
2006;
(
2)
Inorganic
Chlorates:
Occupational
and
Residential
Exposure
Assessment
for
the
Reregistration
Eligibility
Decision
(
RED)
Document
(
Case
4049),
dated
June
13,
2005;
and
(
3)
Sodium
Chlorate:
Occupational
and
Residential
Exposure
Assessment
of
Antimicrobial
Uses
for
the
Reregistration
Eligibility
Decision
Document
dated
January
24,
2005.

a.
Handler
Risks
Occupational
handler
exposure
assessments
are
conducted
by
the
Agency
using
different
levels
of
protection.
The
Agency
typically
evaluates
all
exposures
with
minimal
protection
and
then
adds
protective
measures
in
a
tiered
approach
to
determine
the
level
of
protection
necessary
to
obtain
appropriate
MOEs.
The
lowest
level
(
baseline)
includes
long
sleeve
shirts,
long
pants,
shoes,
and
socks.
A
single
layer
of
PPE
includes
the
addition
of
chemical­
resistant
gloves
to
the
baseline
attire
of
long
sleeves,
long
pants,
shoes,
and
socks.
A
respirator
may
also
be
added
if
there
is
a
concern
for
inhalation
exposure.
If
MOEs
at
that
level
of
PPE
are
less
than
100,
increasing
levels
of
PPE
are
applied
(
i.
e.,
coveralls
are
added
to
provide
a
double
layer
of
protective
clothing
or
respirators).
If
MOEs
are
still
less
than
100
with
maximum
PPE,
then
engineering
controls
are
applied
(
i.
e.,
enclosed
cabs
or
cockpits
and
closed
mixing/
loading
systems).
Note
that
the
lower
levels
of
PPE
protect
against
dermal
exposure,
and
dermal
exposure
is
not
anticipated
for
sodium
chlorate.
The
types
of
protection,
including
PPE
and
engineering
controls,
which
were
used
to
calculate
inhalation
occupational
exposure
from
sodium
chlorate
are
as
follows:
23
°
Baseline:
No
respirator
°
PPE:
Dust/
mist
respirator
with
an
80%
reduction
factor
°
Engineering
Controls:
Enclosed
cockpits
or
enclosed
cabs
Anticipated
use
patterns
and
current
labeling
for
sodium
chlorate
indicate
several
major
occupational
exposure
scenarios
that
can
result
in
handlers
receiving
inhalation
exposures
to
sodium
chlorate,
including
the
antimicrobial
use
of
sodium
chlorate
to
generate
chlorine
dioxide
for
drinking
water
treatment.
These
exposure
scenarios
are
based
on
the
chemical
formulations,
equipment,
and
techniques
that
handlers
can
use
to
make
sodium
chlorate
applications.
Exposures
are
also
considered
based
on
their
duration.
The
Agency
assessed
short­
(
1
to
30
days)
and
intermediate­
term
(
30
days
to
several
months)
exposures
to
sodium
chlorate,
though
the
results
were
essentially
the
same
because
the
toxicological
endpoints
for
short­
and
intermediate­
term
exposures
are
the
same
in
the
case
of
sodium
chlorate.
For
short
and
intermediate­
term
exposures,
MOEs
greater
than
100
are
not
of
concern
to
the
Agency.

Risks
to
handlers
treating
water
systems
are
below
the
Agency's
level
of
concern,
with
inhalation
MOEs
of
800
to
95,000
depending
on
the
size
of
the
generator.
All
sodium
chlorate
applications
to
chlorine
dioxide
generators
occur
in
closed
delivery
systems.
In
addition,
risk
for
most
occupational
handler
scenarios
do
not
exceed
the
Agency's
level
of
concern
of
100
(
i.
e,
most
scenarios
had
MOEs
>
100)
at
the
baseline
level
of
protection.
However,
risks
for
the
following
occupational
scenarios
did
exceed
the
Agency's
level
of
concern
at
baseline
level
of
protection:

°
Mixing/
Loading
liquids
for
groundboom
application
to
industrial/
non­
crop
sites
at
1032
lb
ai
per
acre
(
MOE
=
42)
and
523
lb
ai
per
acre
(
MOE
=
84);
°
Loading
granules
for
tractor­
drawn
spreader
applications
to
industrial/
non­
crop
sites
at
523
lb
ai
per
acre
(
MOE
=
59);
°
Applying
sprays
to
industrial/
non­
crop
sites
using
groundboom
equipment
(
open
cab)
at
1032
lb
ai
per
acre
(
MOE
=
69);
at
523
lb
ai
per
acre
(
MOE
=
140);
°
Mixing/
Loading/
Applying
liquids
for
low
pressure
handwand
applications
to
industrial/
non­
crop
sites
at
1032
lb
ai
per
acre
(
MOE
=
34)
and
523
lb
ai
per
acre
(
MOE
=
67);
and
°
Loading/
Applying
granules
to
industrial/
non­
crop
sites
using
a
belly
grinder
at
523
lb
ai
per
acre
(
MOE
=
65);

Inhalation
handler
risk
for
these
scenarios
did
not
exceed
the
Agency's
level
of
concern
with
the
addition
of
a
dust/
mist
respirator
(
with
an
80%
reduction
factor).
Additionally,
risks
for
certain
scenarios
were
below
the
Agency's
level
of
concern,
without
the
application
of
PPE
or
engineering
controls,
once
lower
application
rates
were
used.
All
risks
of
concern
were
at
the
high
end
of
application
rates
(>
523
lb
ai
per
acre),
whereas
at
lower
rates
the
risks
were
not
of
concern.
Table
10
summarizes
the
risk
results
for
short­
term
and
intermediate­
term
occupational
handlers.
24
Table
10.
Sodium
Chlorate:
Short­
and
Intermediate­
Term
Occupational
Inhalation
Exposure
Exposure
Scenario
Daily
Area
Treated1
Crop/
Target
Application
Rate
(
lb
ai/
A)
Baseline
Inhalation
MOE2
PPE3
Engineering
Controls
Mixer/
Loaders
Cotton,
Corn,
Rice,
Dry
Beans,
Grain
Sorghum,
Flax,
Safflower,
Sunflower,
Soybeans
7.5
190
­­­­­­­
­­­­­­­­
1200
Fallow
Land,
Wheat
6
240
­­­­­­­
­­­­­­­­

Chili
Peppers
(
for
processing
only),
Potatoes
12.5
400
­­­­­­­
­­­­­­­­

Ornamental
Gourds,
Cucurbits
(
grown
for
seed)
6
830
­­­­­­­
­­­­­­­­
Mixing/
Loading
liquids
for
aerial
application
350
Guar
Beans,
Southern
Peas
7.5
670
­­­­­­­
­­­­­­­­

Cotton,
Corn,
Rice,
Dry
Beans,
Grain
Sorghum,
Flax,
Safflower,
Sunflower,
Soybeans
7.5
1200
­­­­­­­
­­­­­­­­
200
Fallow
Land,
Wheat
6
1500
­­­­­­­
­­­­­­­­

Chili
Peppers
(
for
processing
only),
Potatoes
12.5
1800
­­­­­­­
­­­­­­­­

Ornamental
Gourds,
Cucurbits
(
grown
for
seed)
6
3600
­­­­­­­
­­­­­­­­
80
Guar
Beans,
Southern
Peas
7.5
2900
­­­­­­­
­­­­­­­­

1032
42
210
­­­­­­­­

523
84
420
­­­­­­­­
Mixing/
Loading
liquids
for
groundboom
application
40
Industrial/
Non­
Crop
Sites
132
330
­­­­­­­
­­­­­­­­

1032
340
­­­­­­­
­­­­­­­­

523
670
­­­­­­­
­­­­­­­­
Mixing/
Loading
liquids
for
rightsof
way
sprayer
application
5
Rights­
of­
Way
&
Industrial/
Non­
Crop
Sites
132
2700
­­­­­­­
­­­­­­­­

523
59
300
­­­­­­­­

240
130
­­­­­­­
­­­­­­­­
Loading
granules
for
tractor­
drawn
spreader
application
40
Industrial/
Non­
Crop
Sites
161
190
­­­­­­­
­­­­­­­­

Applicators
Aerial
spray
applications
(
enclosed
cockpit)
1200
Cotton,
Corn,
Rice,
Dry
Beans,
Grain
Sorghum,
Flax,
Safflower,
Sunflower,
Soybeans
7.50
­­­­­­­­
­­­­­­­
3400
25
Table
10.
Sodium
Chlorate:
Short­
and
Intermediate­
Term
Occupational
Inhalation
Exposure
Exposure
Scenario
Daily
Area
Treated1
Crop/
Target
Application
Rate
(
lb
ai/
A)
Baseline
Inhalation
MOE2
PPE3
Engineering
Controls
Fallow
Land,
Wheat
6
­­­­­­­­
­­­­­­­
4300
Guar
Beans,
Southern
Peas
7.5
­­­­­­­­
­­­­­­­
12000
Chili
Peppers
(
for
processing
only),
Potatoes
12.5
­­­­­­­­
­­­­­­­
7100
350
Ornamental
Gourds,
Cucurbits
(
grown
for
seed)
6
­­­­­­­­
­­­­­­­
15000
Cotton,
Corn,
Rice,
Dry
Beans,
Grain
Sorghum,
Flax,
Safflower,
Sunflower,
Soybeans
7.5
1900
­­­­­­­
­­­­­­­­
1200
Fallow
Land,
Wheat
6
2400
­­­­­­­
­­­­­­­­

Guar
Beans,
Southern
Peas
7.5
4700
­­­­­­­
­­­­­­­­

Chili
Peppers
(
for
processing
only),
Potatoes
12.5
2800
­­­­­­­
­­­­­­­­
350
Ornamental
Gourds,
Cucurbits
(
grown
for
seed)
6
5900
­­­­­­­
­­­­­­­­

1032
69
340
1200
(
closed
cab)

523
140
­­­­­­­
2300
(
closed
cab)
Groundboom
spray
applications
40
Industrial/
Non­
Crop
Sites
132
540
­­­­­­­
9200
(
closed
cab)

1032
110
­­­­­­­
­­­­­­­­

523
210
­­­­­­­
­­­­­­­­
Rights­
of­
way
sprayer
applications
5
Rights­
of­
Way
&
Industrial/
Non­
Crop
Sites
132
820
­­­­­­­
­­­­­­­­

523
84
420
460
(
closed
cab)

240
180
­­­­­­­
990
(
closed
cab)
Tractor­
drawn
spreader
applications
40
Industrial/
Non­
Crop
Sites
161
270
­­­­­­­
1500
(
closed
cab)

Flaggers
Flagging
for
aerial
spray
applications
350
Various
Agricultural
Crops
12.5
1400
­­­­­­­
­­­­­­­­

Mixer/
Loader/
Applicators
&
Loader/
Applicators
1032
34
170
­­­­­­­­

523
67
330
­­­­­­­­
M/
L/
A
liquids
with
a
low
pressure
handwand
sprayer
2
Industrial/
Non­
Crop
Sites
132
270
­­­­­­­
­­­­­­­­
26
Table
10.
Sodium
Chlorate:
Short­
and
Intermediate­
Term
Occupational
Inhalation
Exposure
Exposure
Scenario
Daily
Area
Treated1
Crop/
Target
Application
Rate
(
lb
ai/
A)
Baseline
Inhalation
MOE2
PPE3
Engineering
Controls
1032
230
­­­­­­­
­­­­­­­­

523
450
­­­­­­­
­­­­­­­­
M/
L/
A
liquids
with
a
handgun
sprayer
5
Industrial/
Non­
Crop
Sites
132
1800
­­­­­­­
­­­­­­­­

523
65
320
­­­­­­­­

240
140
­­­­­­­
­­­­­­­­
L/
A
granules
with
a
belly
grinder
1
Industrial/
Non­
Crop
Sites
161
210
­­­­­­­
­­­­­­­­

523
110
­­­­­­­
­­­­­­­­

240
240
­­­­­­­
­­­­­­­­
L/
A
granules
with
a
push­
type
spreader
5
Industrial/
Non­
Crop
Sites
161
360
­­­­­­­
­­­­­­­­

1.
Amount
treated
is
presented
in
acres/
day.
2.
Inhalation
MOE
=
Oral
NOAEL
(
30
mg/
kg/
day)
/
Daily
Inhalation
Dose.
LOC
for
MOE
is
100.
3.
PPE
dust/
mist
respirator
with
an
80%
reduction
factor.

a.
Incident
Reports
Available
sources
of
incident
data
in
humans
were
reviewed
for
the
active
ingredients
sodium
chlorate
and
calcium
chlorate
(
not
currently
registered).
No
data
were
found
in
any
of
the
available
databases
on
calcium
chlorate,
so
this
review
exclusively
addresses
sodium
chlorate.
Data
were
available
from
the
following
sources:
OPP
Incident
Data
System
(
IDS)
consisting
of
reports
submitted
to
EPA
by
registrants,
other
federal
and
state
health
and
environmental
agencies,
and
the
public,
since
1992;
Poison
Control
Centers
(
1993­
2001);
California
Department
of
Pesticide
Regulation
for
pesticide
poisoning
since
1982;
National
Pesticide
Telecommunications
Network
(
NPTN)
for
ranking
of
the
top
200
active
ingredients
for
which
phone
calls
were
received
during
calendar
years
1984­
1991;
and
National
Institute
of
Occupational
Safety
and
Health's
Sentinel
Event
Notification
System
for
Occupational
Risks
(
NIOSH
SENSOR)
from
1998­
2002.

A
total
of
21
cases
were
recorded
by
the
Poison
Control
Center
from
1993
through
2001.
Seven
reported
minor
symptoms,
and
two
reported
moderate
medical
outcomes,
primarily
due
to
dermal
effects
such
as
swelling
and
rash.
It
is
difficult
to
draw
any
conclusions
from
these
reports
because
of
the
small
number
of
cases.

Detailed
descriptions
of
36
cases
submitted
to
the
California
Pesticide
Illness
Surveillance
Program
(
1982­
2002)
were
reviewed.
However,
sodium
chlorate
was
determined
to
be
the
primary
cause
of
illness
in
just
four
of
these
cases,
and
all
four
occurred
in
an
agricultural
setting
(
three
in
cotton
fields
and
one
unknown).
Two
of
these
cases
were
classified
as
systemic
and
one
each
involved
skin
or
eye
effects.
The
two
systemic
cases
involved
applicators;
one
with
nausea
and
the
other
with
nausea,
headache,
and
itching
skin
after
spraying
for
one
week.
27
Both
of
these
cases
were
classified
as
"
possibly"
due
to
sodium
chlorate.
The
skin
case
involved
a
worker
exposed
to
drift
from
an
adjacent
field
and
the
eye
case
occurred
when
a
worker
bumped
into
a
spray
nozzle
while
getting
off
the
tractor
and
was
splashed
in
the
face.
The
skin
case
was
classified
as
"
probably,"
and
the
eye
case
as
"
definitely,"
due
to
sodium
chlorate.

A
number
of
suicidal
ingestions
of
sodium
chlorate
have
been
reported
in
the
literature,
and
many
of
these
have
led
to
death.
The
chance
of
ingesting
a
fatal
dose
accidentally
is
small
unless
the
compound
is
mistaken
for
a
drug
and
taken
purposely.
However,
a
near­
fatal
poisoning
occurred
when
a
13­
year­
old
boy
"
tasted"
crystals
of
this
weed
killer
which
he
found
in
his
father's
shed.
In
spite
of
intensive
treatment,
recovery
did
not
begin
until
about
the
15th
day
and
required
a
little
over
40
days.

Dermal
absorption
associated
with
agricultural
use
of
sodium
chlorate
is
not
sufficient
to
cause
systemic
poisoning.
Even
by
mouth,
a
large
dose
is
required
to
produce
illness.
A
6.35%
solution
of
potassium
chlorate
was
long
used
as
a
gargle,
or
a
300­
mg
tablet
was
allowed
to
dissolve
slowly
in
the
mouth
to
treat
pharyngitis
before
modern
antibiotics
became
available.
The
toxicities
of
the
sodium
and
potassium
salts
are
similar.
It
was
considered
that
a
dose
of
10,000
mg
was
fatal.
The
smallest
recorded
fatal
dose
was
7500
mg.
However,
vigorous
treatment
saved
one
person
who
had
ingested
about
40,000
mg.

B.
Environmental
Fate
and
Effects
Risk
Assessment
A
summary
of
the
Agency's
environmental
fate
and
effects
risk
assessment
is
presented
below.
For
detailed
discussion
of
all
aspects
of
the
environmental
risk
assessment,
please
see
the
Revised
Environmental
Fate
and
Ecological
Risk
Assessment
of
Sodium
Chlorate,
dated
June
1,
2006;
it
is
available
on
the
internet
and
in
the
public
docket.
This
risk
assessment
was
refined
and
updated
to
incorporate
public
comments
and
data
received
during
the
phase
3
public
comment
period.

1.
Environmental
Fate
and
Transport
Sodium
chlorate,
an
inorganic
salt,
is
not
a
naturally
occurring
chemical.
It
is
made
by
electrolysis
of
brine
under
controlled
temperature
and
pH
conditions
to
optimize
the
efficiency
of
the
process
and
yield.
Since
targeted,
guideline
studies
designed
to
understand
the
environmental
fate
of
chlorate
are
not
available,
open,
peer­
reviewed
chemical
literature
and
descriptive
chemistry
of
the
chlorine
system
were
used
as
the
basis
for
understanding
the
redox
behavior
of
chlorate
(
at
least
on
a
qualitative
basis)
and
for
generating
a
screening­
level
environmental
fate
assessment.

Physical
and
chemical
properties
of
a
chemical
can
be
used
to
identify
potential
routes
of
exposure.
For
example,
the
vapor
pressure
and
Henry's
Law
Constant
provide
an
indication
of
the
potential
to
volatilize
from
soil
and
water
(
partitioning
into
air),
and
the
n­
octanol/
water
partition
coefficient
provides
an
indication
of
the
potential
to
bioaccumulate
in
fish
or
other
aquatic
organisms.
Based
on
the
very
low
vapor
pressure
and
very
high
solubility
of
sodium
chlorate
in
water,
sodium
chlorate
is
not
expected
to
volatilize
from
soil
or
water.
In
addition,
the
low
log
n­
octanol/
water
partition
coefficient
indicates
that
sodium
chlorate
has
low
potential
28
to
bioaccumulate.

As
stated
above,
sodium
chlorate
is
highly
soluble.
In
addition,
sodium
chlorate
is
completely
ionized
in
water,
thus
producing
sodium
(
Na+)
and
the
chlorate
(
ClO
3
­)
anion.
Anions
do
not
bind
readily
to
soil
or
sediment
particulates1
and,
therefore,
are
expected
to
be
very
mobile.
Assuming
that
chlorate
does
not
undergo
any
redox
reactions,
it
is
expected
to
be
very
mobile
and
to
partition
predominantly
into
the
water.
However,
extensive
redox
reactions
are
expected
to
occur
in
the
environment
that
will
reduce
the
concentration
of
chlorate
in
the
water
column.

The
redox
chemistry2
of
chlorate
affects
its
behavior
in
soils
and
natural
water.
Therefore,
identification
of
the
conditions
under
which
chlorate
and
other
oxyanions
of
chlorine
may
predominate
is
an
important
consideration
in
the
environmental
fate
and
risk
assessment
of
chlorate.
The
oxidation­
reduction
reactions
of
chlorate
with
organic
matter
and
other
inorganic
chemical
species
are
very
complex
and
depend
on
the
redox
conditions
of
the
media,
nature
and
concentration
of
reductants,
chlorate
concentration,
temperature,
pH,
and
degree
of
moisture
(
soils).
For
example,
chlorate
is
generally
more
stable
under
alkaline
than
acidic
conditions;
however,
when
a
chemical
element
(
chlorine)
can
exist
in
two
or
more
oxidation
states
(
i.
e.,
chlorite
and
chlorate),
the
redox
potential
of
the
media
also
effects
the
predominance
of
the
reduction
products.
Nitrate
concentrations
in
soil
and
water
(
as
well
as
other
physical
and
chemical
properties
of
soil
and
water)
play
an
important
role
in
the
redox
chemistry
of
chlorate
in
the
environment.

2.
Ecological
Exposure
and
Risk
To
estimate
potential
ecological
risk,
EPA
integrates
the
results
of
exposure
and
ecotoxicity
studies
using
the
risk
quotient
method.
Risk
quotients
(
RQs)
are
calculated
by
dividing
acute
and
chronic
estimated
environmental
concentrations
(
EECs)
by
ecotoxicity
values
for
various
wildlife
and
plant
species.
RQs
are
then
compared
to
levels
of
concern
(
LOCs),
and
when
the
RQ
exceeds
the
level
of
concern
for
a
particular
category,
the
Agency
presumes
a
risk
of
concern
to
that
category.
See
Table
11
below
for
the
Agency's
ecological
LOCs.
Risk
characterization
provides
further
information
on
potential
adverse
effects
and
the
possible
impact
of
those
effects
by
considering
the
fate
of
the
chemical
and
its
degradates
in
the
environment,
organisms
potentially
at
risk,
and
the
nature
of
the
effects
observed.

1
Unless
they
chemisorb
to
soil
or
sediment
particulates.
Chemisorption
of
chlorate
is
unlikely.

2
The
term
"
redox
chemistry"
is
used
as
an
overall
term
for
oxidation
and
reduction
reactions.
Other
terms
that
are
frequently
used
for
oxidizers
are
"
oxidants,"
"
oxidizing
agents."
Reductants
are
frequently
referred
to
as
"
reducing
agents."
All
redox
reactions
require
an
oxidant
and
a
reductant.
Reductants
are
electron
donors,
while
oxidants
are
electron
acceptors.
29
Table
11.
EPA's
Ecological
Levels
of
Concern
(
LOCs)
and
Risk
Presumptions
If
a
calculated
RQ
is
greater
than
the
LOC
presented,
then
the
Agency
presumes
that 
LOC
terrestrial
animals
LOC
aquatic
animals
LOC
plants
Acute
Risk
 
there
is
potential
for
acute
risk;
regulatory
action
may
be
warranted
in
addition
to
restricted
use
classification
0.5
0.5
1.0
Acute
Endangered
Species
 
endangered
species
may
be
adversely
affected
0.1
0.05
1.0
Chronic
Risk
 
there
is
potential
for
chronic
risk
1
1
NA
a.
Terrestrial
Organisms
1.
Birds
and
Mammals
a.
Exposure
Sodium
chlorate
may
be
applied
as
a
spray
(
agricultural
and
nonagricultural
uses)
or
as
granules
(
nonagricultural
uses
only).
The
Agency's
methods
for
assessing
exposure
to
terrestrial
organisms
are
different
for
each
of
these
application
methods
and
are
discussed
below.

For
spray
applications,
the
Agency's
terrestrial
exposure
model
(
ELL­
FATE)
was
used
to
estimate
exposures
and
risks
to
avian
and
mammalian
species.
Input
values
on
avian
and
mammalian
toxicity,
as
well
as
chemical
application
and
foliar
dissipation
half­
life
data,
are
required
to
run
the
model.
The
model
provides
estimates
of
both
exposure
concentrations
and
RQs.
Specifically,
the
model
provides
estimates
of
concentrations
(
maximum
and
average)
of
chemical
residues
on
the
surface
of
different
types
of
foliage
that
may
be
sources
of
exposure
to
avian,
mammalian,
reptilian,
or
terrestrial
phase
amphibian
receptors.
The
surface
residue
concentration
(
ppm)
is
estimated
by
multiplying
the
application
rate
(
pounds
active
ingredient
per
acre)
by
a
value
specific
to
each
food
item.
In
all
screening­
level
assessments,
the
organisms
are
assumed
to
consume
100%
of
their
diet
as
one
food
type.
These
exposure
estimates
are
only
applicable
to
the
applied
pesticide,
sodium
chlorate.
It
is
uncertain
to
what
extent
exposure
to
reduced
species
of
chlorate,
such
as
chlorite,
may
occur.

ELL­
FATE
was
run
for
sodium
chlorate
for
use
on
agricultural
crops
using
the
inputs
provided
in
Table
12
below.
In
the
absence
of
foliar
dissipation
half­
life
data
for
sodium
chlorate,
the
Agency's
default
half­
life
value
of
35
days
was
used
for
all
scenarios.

Table
12.
Input
Parameters
for
Sodium
Chlorate
Used
in
ELL­
FATE
Crop
Maximum
labeled
application
rate
No.
of
applications
Application
interval
Chili
peppers;
white/
Irish
potatoes
12.5
lbs
ai/
A
1
N/
A
Cotton
7.5
lbs
ai/
A
2
30
days
Corn;
flax,
guar;
southern
peas;
rice;
safflower;
sorghum;
soybeans;
sunflower
7.5
lbs
ai/
A
1
N/
A
30
Table
12.
Input
Parameters
for
Sodium
Chlorate
Used
in
ELL­
FATE
Crop
Maximum
labeled
application
rate
No.
of
applications
Application
interval
Agricultural
fallow
land;
dried
beans;
corn;
cucurbits,
flax,
gourds;
guar;
southern
peas;
white/
Irish
potatoes;
rice;
safflower;
sorghum;
soybeans;
sunflower
6
lbs
ai/
A
1
N/
A
The
predicted
upper
90th
percentile
and
mean
chlorate
EECs
(
agricultural
and
nonagricultural
uses)
on
various
wild
animal
food
items
are
presented
in
Table
13
below.

Table
13.
EECs
(
mg
ai/
kg­
food
item)
for
Terrestrial
Animal
Risk
Assessment
for
Sodium
Chlorate
Crops
Predicted
90th
Percentile
Residue
Levels
Predicted
Mean
Residue
Levels
short
grass
tall
grass
broadleaf
forage,
small
insects
fruit,
pods,
seeds,
small
insects
short
grass
tall
grass
broadleaf
forage,
small
insects
fruit,
pods,
seeds,
small
insects
Agricultural
Uses
(
Spray
Applications)

Chili
peppers;
white/
Irish
potatoes
3000
1400
1700
190
1100
450
560
88
Cotton
2800
1300
1600
170
990
420
520
81
Corn;
flax,
guar;
southern
peas;
rice;
safflower;
sorghum;
soybeans;
sunflower
1800
830
1000
110
640
270
340
53
Agricultural
fallow
land;
dried
beans;
corn;
cucurbits,
flax,
gourds;
guar;
southern
peas;
white/
Irish
potatoes;
rice;
safflower;
sorghum;
soybeans;
sunflower
1400
660
810
90
510
220
270
42
Non­
Agricultural
Uses
(
Spray
Applications)

Industrial
sites
such
as
driveways,
paths,
brick
walks,
cobble
gutters,
tennis
courts
12500
5700
7000
780
4400
1900
2300
360
31
Table
13.
EECs
(
mg
ai/
kg­
food
item)
for
Terrestrial
Animal
Risk
Assessment
for
Sodium
Chlorate
Crops
Predicted
90th
Percentile
Residue
Levels
Predicted
Mean
Residue
Levels
short
grass
tall
grass
broadleaf
forage,
small
insects
fruit,
pods,
seeds,
small
insects
short
grass
tall
grass
broadleaf
forage,
small
insects
fruit,
pods,
seeds,
small
insects
Parking
lots,
fence
lines,
building
perimeters,
ditch
banks,
picnic
areas,
vacant
lots,
wood
decks,
bleachers,
cemeteries,
fuel
tanks,
runways,
helo
pads,
etc.
125,000
57,000
70,000
7800
44,000
19,000
23,000
3600
For
granular
applications,
estimation
of
chlorate
loading
per
unit
area
(
mg/
ft2)
is
calculated.
This
approach,
which
is
intended
to
represent
exposure
via
multiple
routes
(
e.
g.,
incidental
ingestion
of
contaminated
soil,
dermal
contact
with
treated
seed
surfaces
and
soil
during
activities
in
the
treated
areas,
preening
activities,
and
ingestion
of
drinking
water
contaminated
with
pesticide)
and
not
just
direct
ingestion,
considers
observed
effects
in
toxicity
studies
and
relates
them
to
the
amount
of
pesticide
applied
to
surface
area.
The
maximum
labeled
application
rate
for
the
active
ingredient
is
the
basis
for
the
exposure
estimate.
The
terrestrial
EECs
for
sodium
chlorate's
non­
agricultural
use
granular
applications
are
presented
in
Table
14
below.

Table
14.
Range
of
Terrestrial
EECs
(
Granular
Applications)
for
Sodium
Chlorate
Non­
Agricultural
Uses
Use
Application
Rate
(
lbs
ai/
A)
EEC
(
mg/
ft2)
a
Parking
lots,
under
asphalt
paving,
fence
lines,
building
perimeters,
ditch
banks,
picnic
areas,
vacant
lots,
wood
decks,
bleachers,
cemeteries,
fuel
tanks,
runways,
helo
pads,
etc.
520
5400
Around
buildings,
storage
areas,
fences,
pumps,
machinery,
fuel
tanks,
recreational
areas,
roadways,
guard
rails,
airports,
rights
of
ways.
160
1700
a.
EEC
=
Application
rate
(
lbs/
Acre)
x
453,000
mg/
lb
÷
43,600
sq
ft/
Acre
b.
Toxicity
Effects
characterization
describes
the
potential
effects
a
pesticide
can
produce
in
a
terrestrial
organism,
and
is
based
on
registrant­
submitted
studies
that
describe
acute
and
chronic
toxicity
effects
for
various
terrestrial
animals.
Table
15
summarizes
the
toxicity
effects
and
reference
values
used
to
assess
risks
for
sodium
chlorate
to
mammals
and
birds.
32
Table
15.
Toxicity
Reference
Values
for
Mammals
and
Birds
for
Sodium
Chlorate.

Exposure
Scenario
Species
Toxicity
Value
Used
in
Risk
Assessment
Effect
Mammals
Acute
Rat
LD50
=
>
5000
mg/
kg­
bw
At
5000
mg/
kg­
bw,
1/
10
animals
died.

Chronic
Rat
NOAEC
=
500
mg/
kg­
bw,
highest
dose
tested
(
approx.
10,000
ppm)
No
reproductive
effects
Birds
Acute
Mallard
duck
LD50
>
2510
mg/
kg­
bw
No
mortality
and
no
clinical
signs
of
toxicity
were
observed.

Chronic
Bobwhite
quail
NOAEC
=
271
ppm
The
LOAEC
was
964
ppm
based
on
effects
on
egg
production
and
thickness,
embryonic
survival,
and
hatchling
body
weight.

c.
Avian
Risk
Estimates
Acute
RQs
for
birds
were
not
calculated,
because
no
mortality
or
signs
of
toxicity
were
observed
in
the
submitted
subacute
or
acute
toxicity
studies
at
concentrations
that
are
above
the
limit
for
these
types
of
studies.

Avian
chronic
RQs
for
agricultural
crops,
at
the
estimated
upper
90th
percentile
residue
levels,
are
presented
in
Table
16
below.
RQ
values
for
all
crops
and
all
avian
food
items
assessed,
except
the
fruits,
pods,
seeds,
and
small
insects
category,
marginally
exceeded
the
Agency's
chronic
LOC
of
1.0.
The
highest
chronic
avian
RQ
was
11
(
chili
pepper/
potato
and
short
grass
scenario).
Chronic
RQs
based
on
mean
EECs,
although
not
presented
here,
would
be
approximately
three
times
lower
for
most
food
items
than
those
based
on
the
90th
percentile
residue
levels
shown
below.

Table
16.
Avian
Chronic
Risk
Quotients
for
Sodium
Chlorate
Agricultural
Uses
Crops
Short
grass
Tall
grass
Broadleaf
forage,
small
insects
Fruit,
pods,
seeds,
small
insects
Chili
peppers;
white/
Irish
potatoes
11.0
5.2
6.3
0.7
Cotton
10.0
4.8
5.9
0.63
Corn;
flax,
guar;
southern
peas;
rice;
safflower;
sorghum;
soybeans;
sunflower
6.6
3.1
3.7
0.41
Agricultural
fallow
land;
dried
beans;
corn;
cucurbits,
flax,
gourds;
guar;
southern
peas;
white/
Irish
potatoes;
rice;
safflower;
sorghum;
soybeans;
sunflower
5.2
2.4
3.0
0.33
Chronic
RQs
for
birds
are
not
presented
for
chlorate's
non­
agricultural
uses
(
granular
or
33
spray).
However,
RQs
would
be
considerably
higher
for
birds
foraging
where
chlorate
is
applied
at
the
rates
assessed
for
the
non­
agricultural
uses.
EECs
ranged
from
12,500
to
125,000
(
short
grass
food
item),
which
would
result
in
chronic
avian
RQs
of
46
to
460.
The
size
of
the
treated
areas
for
these
uses
is
uncertain,
and
this
will
be
discussed
further
in
Section
IV
of
this
document;
therefore,
the
likelihood
that
a
bird
would
consume
100%
of
its
diet
from
a
nonagricultural
area
treated
with
sodium
chlorate
is
uncertain.

d.
Mammalian
Risk
Estimates
Acute
RQs
were
not
calculated
for
mammals.
The
LD50
from
a
core
acute
oral
toxicity
study
in
rats
was
>
5000
mg/
kg­
bw.
In
this
study,
10%
(
1/
10)
of
the
rats
administered
5000
mg/
kg
died.
Mortality
was
not
observed
at
any
other
dose.
Therefore,
the
data
were
not
sufficient
to
allow
for
characterization
of
the
dose­
response
relationship
and
the
proximity
of
the
LD50
to
5000
mg/
kg­
bw
is
uncertain.
For
this
reason,
acute
RQs
were
not
calculated.
However,
Tables
17
and
18
below
present
a
comparison
of
the
body
weight
adjusted
LD50s
to
the
agricultural
and
non­
agricultural
EECs,
respectively,
based
on
current
use
rates
and
the
spray
application
method.
These
ratios
can
be
used
to
estimate
high­
end
acute
risk
to
exposed
mammals.
Actual
RQs
would
be
lower
than
the
values
in
Tables
17
and
18.

Table
17.
Proximity
of
the
lowest
observed
acute
toxic
dose
in
mammals
to
the
upper
90th
percentile
EEC
(
mg/
kg­
bw)
for
the
range
of
maximum
application
rates
for
all
agricultural
uses
Food
item
Size
of
mammal
(
grams)
Adjusted
lowest
observed
toxic
dose
(
mg/
kg­
bw)
Range
of
EECs
(
mg/
kg­
bw)
a
Ratio
of
lowest
observed
toxic
dose
to
the
upper
90th
percentile
EEC
(
unitless)

15
10,989
1400
­
2900
0.13
­
0.26
35
8891
950
­
2000
0.11
­
0.22
Short
grass
1000
3846
200
­
450
0.052
­
0.12
15
10,989
630
­
1300
0.057
­
0.12
35
8891
440
­
910
0.049
­
0.10
Tall
grass
1000
3846
99
­
210
0.026
­
0.055
15
10,989
770
­
1600
0.070
­
0.15
35
8891
540
­
1100
0.061
­
0.12
Broadleaf
plants/
small
insects
1000
3846
120
­
250
0.031
­
0.065
15
10989
86
­
180
<
0.01
­
0.016
35
8891
59
­
120
<
0.01
­
0.013
Fruits,
pods,
large
insects
1000
3846
14
­
28
<
0.01
­
<
0.01
a.
EECs
were
calculated
by
assuming
that
small,
medium,
and
large
mammals
consume
95%,
66%,
and
15%
of
their
body
weight
daily.
Only
the
highest
and
lowest
EECs
from
chlorate's
agricultural
uses
are
used
in
this
assessment.

For
sodium
chlorate's
agricultural
uses,
all
of
the
acute
ratios
are
below
the
Agency's
acute
and
endangered
species
LOC
of
1.0
and
0.1,
respectively,
with
the
exception
of
small
34
mammals
eating
short
grass.
The
highest
exceedence
is
for
15
gram
mammals
eating
short
grass
(
ratio
=
0.26).

Based
on
current
non­
agricultural
use
application
rates,
the
only
group
that
does
not
exceed
the
Agency's
acute
mammalian
LOC
of
1.0
is
animals
eating
fruits,
pods,
or
large
insects
(
ratios
range
from
0.3
to
0.7).
The
Agency's
acute
mammalian
endangered
species
LOC
of
0.1
is
potentially
exceeded
for
all
size
animals
and
food
items.
While
the
ratios
presented
in
Table
18
suggest
that
there
could
be
risk
to
mammals
of
all
sizes
that
forage
in
the
area
where
chlorate
is
used
for
the
non­
agricultural
spray
applications,
the
risk
was
likely
over­
estimated,
since
an
LD50
has
not
been
established.
The
highest
dose
tested
in
the
available
toxicity
studies
(
5000
mg/
kg­
bw)
induced
10%
mortality.
The
proximity
of
the
LD50
to
5000
mg/
kg­
bw
is
uncertain.
Furthermore,
many
of
the
non­
agricultural
uses
will
likely
result
in
small
contiguously
treated
areas;
therefore,
the
likelihood
that
an
animal
will
consume
100%
of
its
diet
from
the
areas
treated
with
sodium
chlorate
is
low
for
some
of
these
uses.
Nonetheless,
the
EECs
were
predicted
to
be
up
to
11
times
higher
than
5000
mg/
kg­
bw
for
the
non­
agricultural
uses.
Therefore,
there
may
be
some
acute
risk
to
mammals
at
levels
of
concern
to
the
Agency
for
nonagricultural
uses.

Table
18.
Proximity
of
the
lowest
observed
acute
toxic
dose
in
mammals
to
the
predicted
EEC
(
mg/
kg­
bw)
for
the
range
of
maximum
application
rates
for
all
non­
agricultural
uses
(
spray
applications)

Food
item
Size
of
mammal
(
grams)
Adjusted
lowest
observed
toxic
dose
(
mg/
kg­
bw)
Range
of
EECs
(
mg/
kg­
bw)
a
Ratio
of
lowest
observed
toxic
dose
to
the
upper
90th
percentile
EEC
(
unitless)

15
10989
11,900
­
119,000
1.1
­
11
35
8891
8200
­
82,000
0.93
­
9.3
Short
grass
1000
3846
1900
­
19,000
0.49
­
4.9
15
10989
5400
­
54,000
0.49
­
4.9
35
8891
3800
­
38,000
0.43
­
4.3
Tall
grass
1000
3846
860
­
8600
0.22
­
2.2
15
10989
6700
­
67,000
0.61
­
6.1
35
8891
4600
­
46,000
0.52
­
5.2
Broadleaf
plants/
small
insects
1000
3846
1100
­
11,000
0.27
­
2.7
15
10989
740
­
7400
0.07
­
0.7
35
8891
520
­
5200
0.06
­
0.6
Fruits,
pods,
large
insects
1000
3846
120
­
1200
0.03
­
0.3
a.
EECs
were
calculated
by
assuming
that
small,
medium,
and
large
mammals
consume
95%,
66%,
and
15%,
respectively,
of
their
body
weight
daily,
and
were
calculated
using
the
lowest
and
highest
labeled
application
rates
(
52
lbs
ai/
A
and
520
lbs
ai/
A)
that
are
most
likely
to
result
in
exposure
RQs
were
not
calculated
for
acute
risk
for
non­
agricultural
granular
applications
for
reasons
previously
discussed.
However,
Table
19
below
presents
a
comparison
of
the
body
weight
adjusted
lowest
observed
toxic
dose
in
rats
(
5000
mg/
kg­
day)
to
the
granular
application
35
EECs
(
mg/
ft2).
These
ratios
indicate
a
potential
acute
risk
to
mammals
of
all
size
classes,
as
the
lowest
ratio
(
0.43
for
large
mammals
and
the
building
and
storage
area
perimeter
scenario)
exceeds
the
acute
endangered
species
LOC
of
0.1.

Table
19.
Range
of
ratios
of
chlorate's
body
weight
adjusted
LD50
to
granular
EECs
(
mg/
ft2)
for
sodium
chlorate's
non­
agricultural
uses
(
granular
formulations)

Use
Body
Weight
(
g)
Rat
LD50
mg/
kg­
bw
EEC
(
mg/
ft2)
a
Ratio
of
LD50
to
EEC
15
10,989
5400
33
35
8891
5400
17
Parking
lots,
under
asphalt
paving,
fence
lines,
building
perimeters,
ditch
banks,
picnic
areas,
vacant
lots,
wood
decks,
bleachers,
cemeteries,
fuel
tanks,
runways,
helo
pads,
etc.

1000
3846
5400
1.4
15
10,989
1700
10
35
8891
1700
5.4
Around
buildings,
storage
areas,
fences,
pumps,
machinery,
fuel
tanks,
recreational
areas,
roadways,
guard
rails,
airports,
rights
of
ways.
1000
3846
1700
0.43
a.
EEC
=
Application
rate
(
lbs/
Acre)
x
453,000
mg/
lb
÷
43,600
sq
ft/
Acre
For
mammals,
the
Agency
typically
evaluates
the
mammalian
reproductive
effects
for
exposures
greater
than
30
days.
Interpretation
of
the
RQs
resulting
from
the
NOAEL
of
500
mg/
kg­
day
observed
in
a
2­
generation
rat
study
is
difficult
in
this
respect.
Although
the
study
did
indicate
some
chronic
effects,
reproduction
effects
were
not
observed
at
any
dose
level
tested.
Because
500
mg/
kg
was
the
highest
dose
tested,
it
is
uncertain
whether
there
is
a
NOAEL
for
reproductive
effects.
In
addition,
if
there
is
an
actual
NOAEL
for
reproductive
effects,
it
could
be
much
greater
than
500
mg/
kg.

However,
the
Agency
calculated
RQs
based
on
the
500
mg/
kg­
day
NOAEL
as
a
conservative
estimate
of
risk,
as
presented
in
Table
20.
Based
on
this
conservative
estimate,
chronic
mammalian
LOC
of
1.0
was
only
slightly
exceeded
for
the
smallest
weight
classes
of
mammals
for
most
food
items
and
the
largest
weight
class
of
mammals
feeding
on
short
grass.
Based
on
the
lack
of
observed
reproductive
effects
in
the
chronic
study
and
the
slight
RQs
exceedances
for
agricultural
uses,
the
Agency
does
not
anticipate
a
chronic
risk
of
concern
to
mammals
from
agricultural
uses
of
sodium
chlorate.

Table
20.
Mammalian
Chronic
Risk
Quotients
for
Sodium
Chlorate's
Agricultural
Uses
(
Spay
Application)

Use
Food
Item
15­
gram
mammal
35­
gram
mammal
1000­
gram
mammal
Single
application
of
12.5
lbs
ai/
A
Chili
peppers;
white/
Irish
potatoes
Short
Grass
2.6
2.2
1.2
36
Table
20.
Mammalian
Chronic
Risk
Quotients
for
Sodium
Chlorate's
Agricultural
Uses
(
Spay
Application)

Use
Food
Item
15­
gram
mammal
35­
gram
mammal
1000­
gram
mammal
Single
application
of
12.5
lbs
ai/
A
Tall
Grass
1.2
1.0
0.55
Broadleaf
plants/
small
insects
1.5
1.3
0.67
Chili
peppers;
white/
Irish
potatoes
Fruits/
pods/
large
insects
0.16
0.14
0.07
Multiple
applications
(
7.5
lbs
ai/
A,
2
applications,
30­
day
interval)

Short
Grass
2.4
2.1
1.1
Tall
Grass
1.1
0.95
0.51
Broadleaf
plants/
small
insects
1.4
1.2
0.62
Cotton
Fruits/
pods/
large
insects
0.15
0.13
0.07
Single
application
(
7.5
lbs
ai/
A)
a
Short
Grass
1.6
1.3
0.72
Tall
Grass
0.72
0.61
0.33
Broadleaf
plants/
small
insects
0.88
0.75
0.40
Corn;
flax,
guar;
southern
peas;
rice;
safflower;
sorghum;
soybeans;
sunflower
Agricultural
fallow
land;
dried
beans;
corn;
cucurbitsa,
flax,
gourds;
guar;
southern
peas;
white/
Irish
potatoes;
rice;
safflower;
sorghum;
soybeans;
sunflower
Fruits/
pods/
large
insects
0.10
0.08
0.04
a.
EECs
and
RQs
are
similar
for
the
7.5lbs
a.
i/
A
(
corn,
et
al.)
and
6.0
lbs
a.
i./
A
(
agricultural
fallow
land,
et
al.)
and
single
applications,
and
LOC
exceedances
are
equivalent;
therefore,
only
results
from
the
single
application
of
7.5
lbs
ai/
A
are
presented.

Reproduction
RQs
were
not
calculated
for
chlorate's
non­
agricultural
uses
(
spray
or
granular
applications).
However,
based
on
the
high
application
rates
and
resulting
high
potential
EECs,
risks
from
chlorate's
non­
agricultural
uses
could
be
considerably
higher
than
risks
presented
for
agricultural
uses.

2.
Non­
Target
Insects
EPA
currently
does
not
estimate
RQs
for
terrestrial
non­
target
insects.
Furthermore,
the
Agency
has
no
insect
toxicity
data
for
sodium
chlorate.
37
3.
Non­
Target
Terrestrial
Plants
Based
on
chlorate's
non­
selective
mode
of
action
and
lack
of
adequate
toxicity
data,
the
Agency
presumes
risk
to
non­
target
terrestrial
plants
at
levels
above
the
Agency's
level
of
concern
for
all
uses.
The
risks
to
plants
cannot
be
quantified
at
this
time
due
to
lack
of
data;
however,
the
Agency
will
require
data
to
address
this
uncertainty.

b.
Aquatic
Organisms
At
the
present
time,
there
is
no
methodology
to
estimate
exposure
concentrations
in
water
for
non­
metal
inorganic
chemical
species
that
can
be
found
in
different
oxidation
states
(
e.
g.,
for
inorganic
chemical
species
that
can
exhibit
extensive
pH­
pE
dependent
redox
chemistry,
such
as
the
chlorine
system).
As
an
approximation
on
the
impact
of
chlorate
on
surface
water
quality,
the
Tier
I
GENEEC­
2
simulation
model
was
used
to
estimate
exposure
concentrations
in
aquatic
systems.
Extreme
assumptions
in
the
environmental
persistence
of
chlorate
were
made
that
resulted
in
high­
end
exposure
concentrations
in
the
standard
ecological
pond
scenario.
The
predicted
chlorate
concentrations
are
believed
to
be
high
because
the
chemical
speciation
of
chlorate
was
not
considered
in
the
assessment.
As
previously
discussed,
under
thermodynamic
equilibrium
conditions,
chloride
is
likely
the
predominant
species
in
natural
environments.
This
analysis,
however,
indicates
that
chlorate
can
be
reduced
to
chloride,
but
not
how
fast
the
reduction
will
occur.
Since
there
are
no
input
parameters
for
the
model
that
take
into
account
the
redox
behavior
of
chlorate,
it
was
assumed
that
unchanged
chlorate
runs
off
into
surface
water,
where
it
remains
as
chlorate.

Unlike
the
drinking
water
assessment
described
in
the
human
health
risk
assessment
section
of
this
document,
the
exposure
values
used
in
the
ecological
risk
assessment
do
not
include
the
Index
Reservoir
(
IR)
and
Percent
Cropped
Area
(
PCA)
factor
refinements.
These
factors
represent
a
drinking
water
reservoir,
not
the
variety
of
aquatic
habitats
relevant
to
a
risk
assessment
for
aquatic
animals,
such
as
ponds
adjacent
to
treated
fields.
Therefore,
the
EEC
values
used
to
assess
exposure
and
risk
to
aquatic
animals
are
not
the
same
as
those
used
to
assess
exposure
and
risk
to
humans
from
pesticides
in
drinking
water.

1.
Fish
Acute
toxicity
studies
for
both
freshwater
and
marine/
estuarine
fish
were
consistent
with
a
"
practically
non­
toxic"
designation
for
fish.
No
effects
were
observed
in
sheepshead
minnows
(
estuarine/
marine)
or
bluegill
(
freshwater)
fish
at
up
to
1000
mg/
L.
For
inorganic
chlorates,
RQs
were
not
calculated
for
freshwater
or
estuarine/
marine
fish,
since
the
proximity
of
the
LC50
to
the
highest
concentration
tested
(
1000
mg/
L)
could
not
be
estimated.
Although
1000
mg/
L
is
not
an
LC50,
which
is
the
toxicity
value
usually
used
to
derive
RQs,
this
value
was
used
only
to
estimate
high­
end
risk
to
exposed
fish.
EECs
for
both
agricultural
and
nonagricultural
uses
of
sodium
chlorate
were
more
than
20­
fold
lower
than
the
toxic
concentration
observed
in
fish
of
1000
mg/
L
(
all
RQs
would
be
less
than
0.05,
and
below
the
Agency's
acute
LOC
of
0.5
and
the
acute
endangered
species
LOC
of
0.05).
Therefore,
acute
risk
to
freshwater
and
estuarine/
marine
fish
is
not
of
concern
to
the
Agency.

No
chronic
toxicity
studies
in
fish
have
been
submitted
to
the
Agency,
nor
were
any
38
identified
in
the
ECOTOX
database.
However,
the
Agency
will
require
data
to
address
this
area
of
uncertainty.

2.
Aquatic
Invertebrates
For
freshwater
invertebrates,
acute
RQs
are
based
on
the
EC50
of
920
mg/
L
(
daphnids)
and
EECs
calculated
by
GENEEC­
2;
these
are
presented
in
Table
21
below.
All
RQs
are
below
the
acute
LOC
of
0.5
and
the
endangered
species
acute
LOC
of
0.05;
therefore,
acute
risk
to
freshwater
invertebrates
is
not
of
concern
to
the
Agency.

Table
21.
Acute
Freshwater
Aquatic
Invertebrate
Risk
Quotients
Use
Application
Rate
Range
Maximum
EEC
EC50
RQ
Agricultural
uses
4.5 
7.5
lb
ai/
A
0.91
mg/
L
920
mg/
L
<
0.01
Non­
agricultural
uses
132 
520
lb
ai/
A
39
mg/
L
920
mg/
L
<
0.042
For
saltwater
invertebrates,
acute
RQs
were
not
calculated,
because
the
proximity
of
the
LC50
from
a
supplemental
96­
hr
study
(
mysid
shrimp)
to
the
highest
concentration
tested
(
1000
mg/
L),
could
not
be
estimated.
However,
the
ratios
of
chlorate's
EECs
(
agricultural
and
nonagricultural
uses)
to
the
concentration
of
1000
mg/
L
were
calculated,
and
the
highest
resulting
value
was
0.04.
As
this
is
well
below
the
acute
LOC
of
0.5,
in
addition
to
the
endangered
species
acute
LOC
of
0.05,
acute
risk
to
saltwater
invertebrates
is
not
of
concern
to
the
Agency.

Chronic
risk
to
invertebrates
was
not
assessed,
since
treatment­
related
effects
were
not
observed
at
any
concentration
in
available
studies.

3.
Aquatic
Plants
Toxicity
(
EC50)
and
exposure
(
EEC)
values,
as
well
as
RQs,
for
non­
endangered
aquatic
plants
are
shown
in
Tables
22.
For
non­
endangered
aquatic
plants,
the
Agency
calculates
RQs
by
dividing
EECs
by
EC50
values..
For
sodium
chlorate,
the
LOC
(
1.0)
was
not
exceeded
for
either
the
agricultural
or
nonagricultural
uses
of
chlorate;
therefore,
risk
to
non­
endangered
aquatic
plants
is
not
of
concern
to
the
Agency.

Table
22.
Risk
Quotients
for
Non­
endangered
Aquatic
Plants
Use
Maximum
Peak
EEC
Algal
EC50
Duckweed
EC50
Algal
RQ
Duckweed
RQ
Agricultural
Up
to
0.9
mg/
L
133
mg/
L
43
mg/
L
<
0.01
0.02
Non­
agricultural
Up
to
39
mg/
L
133
mg/
L
43
mg/
L
Up
to
0.29
0.91
The
RQs
for
endangered
aquatic
plants
are
presented
in
Table
23.
The
Agency
calculates
39
RQs
for
endangered
aquatic
plants
by
dividing
EECs
by
NOAECs.
For
endangered
aquatic
plants,
the
Agency's
LOC
(
1.0)
was
exceeded
for
sodium
chlorate's
non­
agricultural
uses
(
RQ
=
12.6).
However,
the
EECs
for
the
non­
agricultural
use
sites
are
likely
conservative;
therefore,
additional
information
on
use
patterns
would
allow
for
characterization
of
potential
risks
to
aquatic
plants.
Also,
testing
on
three
additional
required
plant
species
is
required
for
herbicides.
Overall,
additional
data
are
needed
to
allow
for
a
full
characterization
of
potential
risk
to
aquatic
plants.

Table
23.
Endangered
Species
Algal
Risk
Quotients
Agricultural
and
Non­
Agricultural
Uses
Use
Maximum
Peak
EEC
Algal
EC50
Duckweed
EC50
Algal
RQ
Duckweed
RQ
Agricultural
Up
to
0.9
mg/
L
62.5
mg/
L
3.1
mg/
L
Up
to
0.014
Up
to
0.29
Non­
Agricultural
Up
to
39
mg/
L
62.5
mg/
L
3.1
mg/
L
Up
to
0.62
Up
to
12.6
c.
Endangered
Species
The
Agency's
screening
level
assessment
results
in
the
determination
that
sodium
chlorate
will
have
no
acute
risks
to
birds,
no
acute
risks
to
fish
(
freshwater
and
estuarine/
marine),
and
no
acute
or
chronic
risks
to
aquatic
invertebrates
(
freshwater
and
estuarine/
marine).

However,
the
preliminary
risk
assessment
for
endangered
species
indicates
that
RQs
exceed
endangered
species
LOCs
for
chronic
risks
to
birds
(
RQs
up
to
11
for
agricultural
uses
and
greater
for
non­
agricultural
uses);
acute
risks
to
mammals
(
RQs
up
to
33);
chronic
risks
to
mammals
(
RQs
up
to
1.2
for
agricultural
uses
and
greater
for
non­
agricultural
uses);
and
risks
to
aquatic
plants
(
RQs
up
to
13).
Risks
could
not
be
calculated
for
terrestrial
plants
and
for
chronic
risks
to
fish;
however,
the
Agency
will
be
requiring
data.

Further,
potential
indirect
effects
to
any
species
dependent
upon
a
species
that
experiences
effects
from
use
of
sodium
chlorate
can
not
be
precluded
based
on
the
screening
level
ecological
risk
assessment.
These
findings
are
based
solely
on
EPA's
screening
level
assessment
and
do
not
constitute
"
may
affect"
findings
under
the
Endangered
Species
Act.

d.
Ecological
Incidents
A
review
of
the
Ecological
Incident
Information
System
(
EIIS)
database
for
ecological
incidents
involving
chlorate
was
completed
on
October
25,
2004.
There
were
no
chlorate
incidents
in
the
database
40
IV.
Risk
Management,
Reregistration,
and
Tolerance
Reassessment
A.
Determination
of
Reregistration
Eligibility
Section
4(
g)(
2)(
A)
of
FIFRA
calls
for
the
Agency
to
determine,
after
submission
of
relevant
data
concerning
an
active
ingredient,
whether
or
not
products
containing
the
active
ingredient
are
eligible
for
reregistration.
The
Agency
has
previously
identified
and
required
the
submission
of
the
generic
(
i.
e.,
active
ingredient­
specific)
data
required
to
support
reregistration
of
products
containing
sodium
chlorate
as
an
active
ingredient.
The
Agency
has
completed
its
review
of
these
generic
data,
and
has
determined
that
the
data
are
sufficient
to
support
reregistration
of
all
products
containing
sodium
chlorate.

The
Agency
has
completed
its
assessment
of
the
dietary,
occupational,
residential,
and
ecological
risk
associated
with
the
use
of
pesticide
products
containing
the
active
ingredient
sodium
chlorate.
Based
on
a
review
of
these
data
and
on
public
comments
on
the
Agency's
assessments
for
the
active
ingredient
sodium
chlorate,
the
Agency
has
sufficient
information
on
the
human
health
and
ecological
effects
to
make
decisions
as
part
of
the
tolerance
reassessment
process
under
FFDCA
and
reregistration
process
under
FIFRA,
as
amended
by
FQPA.
The
Agency
has
determined
that
sodium
chlorate­
containing
products
are
eligible
for
reregistration
provided
that:
(
i)
the
risk
mitigation
measures
outlined
in
this
document
are
adopted,
(
ii)
label
amendments
are
made
to
reflect
these
measures,
and
(
iii)
a
safety
finding
can
be
made
for
sodium
chlorite.
Label
changes
are
described
in
Section
V.
Appendix
A
summarizes
the
uses
of
sodium
chlorate
that
are
eligible
for
reregistration.
Appendix
B
identifies
the
generic
data
requirements
that
the
Agency
reviewed
as
part
of
its
determination
of
reregistration
eligibility
of
sodium
chlorate,
and
lists
the
submitted
studies
that
the
Agency
found
acceptable.
Data
gaps
are
identified
as
generic
data
requirements
that
have
not
been
satisfied
with
acceptable
data.

Based
on
its
evaluation
of
sodium
chlorate,
the
Agency
has
determined
that
sodium
chlorate
products,
unless
labeled
and
used
as
specified
in
this
document,
would
present
risks
inconsistent
with
FIFRA.
Accordingly,
should
a
registrant
fail
to
implement
any
of
the
risk
mitigation
measures
identified
in
this
document,
the
Agency
may
take
regulatory
action
to
address
the
risk
concerns
from
the
use
of
sodium
chlorate.
If
all
changes
outlined
in
this
document
are
incorporated
into
the
product
labels,
then
all
current
risks
for
sodium
chlorate
will
be
adequately
mitigated
for
the
purposes
of
this
determination
under
FIFRA.
Once
an
Endangered
Species
assessment
is
completed,
further
changes
to
these
registrations
may
be
necessary
as
explained
in
Section
III.
B.
2.
c.
of
this
document.

B.
Public
Comments
and
Responses
Through
the
Agency's
public
participation
process,
EPA
worked
with
stakeholders
and
the
public
to
reach
the
regulatory
decisions
for
sodium
chlorate.
EPA
released
its
sodium
chlorate
preliminary
risk
assessments
for
public
comment
on
February
1,
2006,
for
a
60­
day
public
comment
period
(
Phase
3
of
the
public
participation
process).
During
the
public
comment
period
on
the
risk
assessments,
which
closed
on
April
3,
2006,
the
Agency
received
comments
from
the
sodium
chlorate
task
force,
technical
registrants,
and
private
citizens.
These
comments
in
their
entirety,
41
responses
to
the
comments,
as
well
as
the
preliminary
and
revised
risk
assessments,
are
available
in
the
public
docket
(
OPP­
2005­
0507)
at
http:
www.
regulations.
gov.

C.
Regulatory
Position
1.
Food
Quality
Protection
Act
Findings
a.
"
Risk
Cup"
Determination
As
part
of
the
FQPA
tolerance
reassessment
process,
EPA
assessed
the
risks
associated
with
this
pesticide.
The
Agency
has
determined
that,
if
the
mitigation
described
in
this
document
is
adopted
and
labels
are
amended,
and
a
safety
finding
can
be
made
for
sodium
chlorite,
human
health
risks
as
a
result
of
exposures
to
sodium
chlorate
are
within
acceptable
levels.
In
other
words,
EPA
has
concluded
that
the
exemptions
from
tolerances
for
sodium
chlorate
meet
FQPA
safety
standards.
In
reaching
this
determination,
EPA
has
considered
the
available
information
on
the
special
sensitivity
of
infants
and
children,
as
well
as
exposures
to
sodium
chlorate
from
all
possible
sources.

b.
Determination
of
Safety
to
U.
S.
Population
The
Agency
has
determined
that
provided
a
safety
finding
can
be
made
for
sodium
chlorite,
the
Agency
has
determined
that
the
established
tolerance
exemptions
for
sodium
chlorate,
with
amendments
and
changes
as
specified
in
this
document,
meet
the
safety
standards
under
the
FQPA
amendments
to
section
408(
b)(
2)(
D)
of
the
FFDCA,
and
that
there
is
a
reasonable
certainty
no
harm
will
result
to
the
general
population
or
any
subgroup
from
the
use
of
sodium
chlorate.
In
reaching
this
conclusion,
the
Agency
has
considered
all
available
information
on
the
toxicity,
use
practices
and
exposure
scenarios,
and
the
environmental
behavior
of
sodium
chlorate.
As
discussed
in
Section
III,
the
acute,
chronic,
and
cancer
dietary
(
food
and
drinking
water)
risks
from
sodium
chlorate
are
below
the
Agency's
acute
and
chronic
LOC,
provided
that
mitigation
measures
outlined
in
this
document
are
adopted
and
labels
are
amended.

c.
Determination
of
Safety
to
Infants
and
Children
EPA
has
determined
that
the
established
tolerance
exemptions
for
sodium
chlorate,
with
amendments
and
changes
as
specified
in
this
document,
and
provided
that
a
safety
finding
can
be
made
for
sodium
chlorite,
meet
the
safety
standards
under
the
FQPA
amendments
to
section
408(
b)(
2)(
C)
of
the
FFDCA,
that
there
is
a
reasonable
certainty
of
no
harm
for
infants
and
children.
The
safety
determination
for
infants
and
children
considers
factors
on
the
toxicity,
use
practices
and
environmental
behavior
noted
above
for
the
general
population,
but
also
takes
into
account
the
possibility
of
increased
dietary
exposure
due
to
the
specific
consumption
patterns
of
infants
and
children,
as
well
as
the
possibility
of
increased
susceptibility
to
the
toxic
effects
of
sodium
chlorate
residues
in
this
population
subgroup.

In
determining
whether
or
not
infants
and
children
are
particularly
susceptible
to
toxic
effects
from
exposure
to
residues
of
sodium
chlorate,
the
Agency
considered
the
completeness
of
42
the
hazard
database
for
developmental
and
reproductive
effects,
the
nature
of
the
effects
observed,
and
other
information.
On
the
basis
of
this
information,
the
FQPA
SF
has
been
reduced
to
1X
for
sodium
chlorate.
The
rationale
for
the
decisions
on
the
FQPA
SF
can
be
found
in
Section
III
and
the
following
document:
HED
Chapter
of
the
Reregistration
Eligibility
Decision
Document
(
RED),
dated
January
26,
2006.

2.
Endocrine
Disruptor
Effects
EPA
is
required
under
the
FFDCA,
as
amended
by
FQPA,
to
develop
a
screening
program
to
determine
whether
certain
substances
(
including
all
pesticide
active
and
other
ingredients)
"
may
have
an
effect
in
humans
that
is
similar
to
an
effect
produced
by
a
naturally
occurring
estrogen,
or
other
endocrine
effects
as
the
Administrator
may
designate."
Following
recommendations
of
its
Endocrine
Disruptor
Screening
and
Testing
Advisory
Committee
(
EDSTAC),
EPA
determined
that
there
was
a
scientific
basis
for
including,
as
part
of
the
program,
the
androgen
and
thyroid
hormone
systems,
in
addition
to
the
estrogen
hormone
system.
EPA
also
adopted
EDSTAC's
recommendation
that
EPA
include
evaluations
of
potential
effects
in
wildlife.
For
pesticides,
EPA
will
use
FIFRA
and,
to
the
extent
that
effects
in
wildlife
may
help
determine
whether
a
substance
may
have
an
effect
in
humans,
FFDCA
authority
to
require
the
wildlife
evaluations.
As
the
science
develops
and
resources
allow,
screening
for
additional
hormone
systems
may
be
added
to
the
Endocrine
Disruptor
Screening
Program
(
EDSP).

The
available
toxicity
studies
on
sodium
chlorate
demonstrate
the
thyroid
gland
to
be
its
target
of
toxicity.
The
endpoints
selected
to
assess
chronic
dietary
risk
and
short­
and
intermediate­
term
oral
and
inhalation
risks
in
this
document
are
protective
of
the
observed
thyroid
effects
seen
in
the
available
toxicity
studies.
When
additional
appropriate
screening
and/
or
testing
protocols
being
considered
under
the
Agency's
EDSP
have
been
developed,
sodium
chlorate
may
be
subjected
to
further
screening
and/
or
testing
to
better
characterize
effects
related
to
endocrine
disruption.

3.
Cumulative
Risks
The
FFDCA,
as
amended
by
the
FQPA,
requires
that
the
Agency
consider
"
available
information"
concerning
the
cumulative
effects
of
a
particular
pesticide's
residues
and
"
other
substances
that
have
a
common
mechanism
of
toxicity."
The
reason
for
consideration
of
other
substances
is
due
to
the
possibility
that
low­
level
exposures
to
multiple
chemical
substances
that
cause
a
common
toxic
effect
by
a
common
toxic
mechanism
could
lead
to
the
same
adverse
health
effect
as
would
a
higher
level
of
exposure
to
any
of
the
substances
individually.
The
EPA
has
not
made
a
common
mechanism
of
toxicity
finding
as
to
sodium
chlorate
and
any
other
substances.
For
the
purposes
of
this
reregistration
eligibility
decision
(
RED),
therefore,
EPA
has
not
assumed
that
the
inorganic
chlorates
have
a
common
mechanism
of
toxicity
with
other
substances.
For
information
regarding
EPA's
efforts
to
determine
which
chemicals
have
a
common
mechanism
of
toxicity
and
to
evaluate
the
cumulative
effects
of
such
chemicals,
see
the
policy
statements
released
by
EPA's
Office
of
Pesticide
Programs
concerning
common
mechanism
determinations
and
procedures
for
cumulating
effects
from
substances
found
to
have
a
common
mechanism
on
EPA's
website
at
http://
www.
epa.
gov/
pesticides/
cumulative/.
43
4.
Endangered
Species
The
Agency's
screening­
level
assessment
results
in
the
determination
that
sodium
chlorate
will
have
no
acute
risks
to
birds,
no
acute
risks
to
fish
(
freshwater
and
estuarine/
marine),
and
no
acute
or
chronic
risks
to
aquatic
invertebrates
(
freshwater
and
estuarine/
marine).

However,
the
preliminary
risk
assessment
for
endangered
species
indicates
that
RQs
exceed
endangered
species
LOCs
for
chronic
risks
to
birds
(
RQs
up
to
11
for
agricultural
uses
and
greater
for
non­
agricultural
uses);
acute
risks
to
mammals
(
RQs
up
to
33);
chronic
risks
to
mammals
(
RQs
up
to
1.2
for
agricultural
uses
and
greater
for
non­
agricultural
uses);
and
risks
to
aquatic
plants
(
RQs
up
to
13).
Risks
could
not
be
calculated
for
terrestrial
plants
and
for
chronic
risks
to
fish;
however,
the
Agency
will
be
requiring
data.

Further,
potential
indirect
effects
to
any
species
dependent
upon
a
species
that
experiences
effects
from
use
of
sodium
chlorate
cannot
be
precluded
based
on
the
screeninglevel
ecological
risk
assessment.
These
findings
are
based
solely
on
EPA's
screening­
level
assessment
and
do
not
constitute
"
may
affect"
findings
under
the
Endangered
Species
Act.

The
Agency
has
developed
the
Endangered
Species
Protection
Program
to
identify
pesticides
whose
use
may
cause
adverse
impacts
on
endangered
and
threatened
species,
and
to
implement
mitigation
measures
that
address
these
impacts.
The
Endangered
Species
Act
(
ESA)
requires
federal
agencies
to
ensure
that
their
actions
are
not
likely
to
jeopardize
listed
species
or
adversely
modify
designated
critical
habitat.
To
analyze
the
potential
of
registered
pesticide
uses
that
may
affect
any
particular
species,
EPA
uses
basic
toxicity
and
exposure
data
developed
for
the
REDs
and
considers
it
in
relation
to
individual
species
and
their
locations
by
evaluating
important
ecological
parameters,
pesticide
use
information,
geographic
relationship
between
specific
pesticide
uses
and
species
locations,
and
biological
requirements
and
behavioral
aspects
of
the
particular
species,
as
part
of
a
refined
species­
specific
analysis.
When
conducted,
this
species­
specific
analysis
will
take
into
consideration
any
regulatory
changes
in
this
RED
that
are
being
implemented
at
that
time.

Following
this
future
species­
specific
analysis,
a
determination
that
there
is
a
likelihood
of
potential
impact
to
a
listed
species
or
its
critical
habitat
may
result
in:
limitations
on
the
use
of
sodium
chlorate,
other
measures
to
mitigate
any
potential
impact;
or
consultations
with
the
Fish
and
Wildlife
Service
or
the
National
Marine
Fisheries
Service
as
necessary.
If
the
Agency
determines
use
of
sodium
chlorate
"
may
affect"
listed
species
or
their
designated
critical
habitat,
EPA
will
employ
the
provisions
in
the
Services
regulations
(
50
CFR
Part
402).
Until
that
species­
specific
analysis
is
completed,
the
risk
mitigation
measures
being
implemented
through
this
RED
will
reduce
the
likelihood
that
endangered
and
threatened
species
may
be
exposed
to
sodium
chlorate
at
levels
of
concern.
EPA
is
not
requiring
specific
sodium
chlorate
label
language
at
the
present
time
relative
to
threatened
and
endangered
species.
If,
in
the
future,
specific
measures
are
necessary
for
the
protection
of
listed
species,
the
Agency
will
implement
them
through
the
Endangered
Species
Protection
Program.
44
D.
Tolerance
Reassessment
Summary
Table
24
summarizes
the
reassessment
of
the
sodium
chlorate
tolerance
exemptions
pending
a
safety
finding
can
be
made
for
sodium
chlorite.
40
CFR
must
be
updated
to
reflect
the
tolerance
exemptions
in
the
table
below.
The
tolerance
exemptions
listed
in
40
CFR
must
be
reorganized
in
order
to:
(
i)
incorporate
the
recommendations
made
by
the
Agency
concerning
the
sodium
chlorate
residues
of
concern
that
need
to
be
regulated
for
plant
and
animal
commodities;
(
ii)
include
tolerance
exemptions
that
are
needed
to
cover
sodium
chlorate
residues
of
concern
in/
on
the
raw
agricultural
commodities
and
processed
commodities
of
rotational
crops;
and
(
iii)
conform
with
the
requirements
of
FQPA.

Table
24.
Tolerance
Reassessment
Summary
for
Sodium
Chlorate
Listed
under
40
CFR
180.1020(
a)

Commodity
Current
Tolerance
(
ppm)
Tolerance
Reassessment
(
ppm)
[
Correct
Definition]
Comments
Beans,
dry,
edible
Exempt
Exempt
[
Bean,
dry,
seed]

Corn,
fodder
Exempt
Corn,
forage
Exempt
Corn,
grain
Exempt
Exempt
[
Corn,
field,
stover;
Corn,
field,
forage;
Corn,
field,
grain;
Corn,
sweet,
stover;
Corn,
pop,
stover;
Corn,
pop,
grain;
Corn,
sweet,
forage]

Cottonseed
Exempt
Exempt
[
Cotton,
undelinted
seed]

Flaxseed
Exempt
Exempt
[
Flax,
seed]

Flax,
straw
Exempt
Revoke
Flax
straw
is
not
listed
in
Table
1
of
OPPTS
860.1000
Guar
beans
Exempt
Exempt
[
Guar,
seed]

Peas,
southern
Exempt
Exempt
[
Pea,
southern,
seed]

Potatoes
Exempt
Exempt
[
Potato]

Peppers,
chili
Exempt
Exempt
[
Pepper,
nonbell]

Rice
Exempt
Rice,
straw
Exempt
Exempt
[
Rice,
grain;
Rice,
straw]

Safflower,
grain
Exempt
Exempt
[
Safflower,
seed]

Sorghum,
grain
Exempt
Sorghum,
fodder
Exempt
Sorghum,
forage
Exempt
Exempt
[
Sorghum
grain,
grain;
Sorghum,
grain,
stover;
Sorghum,
grain,
forage]

Soybeans
Exempt
Exempt
[
Soybean,
seed]
45
Table
24.
Tolerance
Reassessment
Summary
for
Sodium
Chlorate
Listed
under
40
CFR
180.1020(
a)

Sunflower
seed
Exempt
Exempt
[
Sunflower,
seed]

Wheat
None
Exempt
[
Wheat,
grain]

Listed
under
40
CFR
180.1020(
b)

Wheat
Exempt
Revoke
[
Wheat,
grain]
Time­
limited
exemption
currently
expires
on
12/
31//
2006
Existing
Exemptions
Sodium
chlorate
is
currently
registered
for
preharvest
and
foliar
applications
as
a
defoliant
or
desiccant
to
the
following
food/
feed
crops:
beans,
corn,
cotton,
flax,
guar,
chili
peppers,
potatoes,
rice,
safflower,
sorghum
(
grain),
southern
peas
(
i.
e.,
cowpeas),
soybeans,
and
sunflowers.

Sodium
chlorate
exemptions
under
40
CFR
180.1020(
a)
from
the
requirement
of
a
tolerance
should
be
amended
as
follows
to:
(
1)
specify
defoliant
and
desiccant
use
only,
(
2)
specify
use
on
crops
rather
than
raw
agricultural
commodities,
and
(
3)
include
an
exemption
for
wheat
(
grain).

40
CFR
180.1020(
a)
Sodium
chlorate
is
exempt
from
the
requirement
of
a
tolerance
for
residues
when
used
as
a
defoliant
or
desiccant
in
accordance
with
good
agricultural
practice
on
the
following
crops:
Bean
(
dry,
seed),
Corn
(
field,
stover),
Corn
(
field,
forage),
Corn
(
field,
grain),
Corn
(
sweet,
stover),
Corn
(
pop,
stover),
Corn
(
pop,
grain);
Corn
(
sweet,
forage),
Cotton
(
undilented
seed),
Flax
(
seed),
Guar
(
seed),
Peas
(
southern,
seed),
Peppers
(
nonbell),
Potatoes,
Rice
(
grain),
Rice
(
straw),
Safflower
(
seed),
Sorghum
(
grain,
grain),
Sorghum
(
grain,
stover),
Sorghum
(
grain,
forage),
Soybean
(
seed),
and
Sunflower
(
seed).

Under
40
CFR
180.1020(
b),
a
time­
limited
exemption
from
the
requirement
of
a
tolerance
is
established
for
residues
of
the
defoliant/
desiccant
in
connection
with
use
of
the
pesticide
under
section
18
emergency
exemptions
granted
by
EPA.
This
exemption
was
granted
for
wheat
and
expires
12/
31/
06.
The
use
of
sodium
chlorate
on
wheat
is
also
addressed
herein
with
the
intention
to
convert
the
time­
limited
exemption
status
to
a
permanent
exemption
from
the
requirement
of
a
tolerance
under
40
CFR.
1020
(
a).
The
proposed
use
rate
is
for
a
single
application
of
sodium
chlorate
to
wheat
at
6
lbs
ai/
A
with
a
3­
day
PHI.

Needed
Exemptions
Sodium
chlorate
(
873301)
as
an
inert
ingredient
in
herbicide
formulation
products
can
be
applied
professionally
to
agricultural
(
corn,
guava,
macadamia
nuts,
sorghum
grain,
sugarcane,
wheat),
commercial
(
non­
agricultural),
and
residential
sites.
These
conventional
pesticide
products
contain
<
1
%
sodium
chlorate
and
can
be
applied
at
rates
no
greater
than
0.07
lb
(
as
sodium
chlorate)
per
acre.
46
Potassium
chlorate
(
900583)
as
an
inert
ingredient
in
fungicide
products
can
be
applied
in
poultry
premises.
These
conventional
pesticide
products
contain
<
20%
potassium
chlorate
and
can
be
applied
at
rates
not
greater
than
0.01
lb
(
as
potassium
chlorate)
per
500
ft3.
See
Table
25
below
for
the
tolerance
exemptions
needed
for
sodium
chlorate.

Table
25.
Tolerance
Exemptions
Needed
for
sodium
chlorate
Tolerance
Exemption
Expression
PC
Code
CAS
Reg
No.
40
CFR
§
Use
(
Pesticidal)
List
Classification
Sodium
chlorate
873301
7775­
09­
9
180.920
1
Stabilizer
3
Potassium
chlorate
900583
3811­
04­
9
180.930
2
Oxidizer
3
1.
Residues
listed
in
40
CFR
§
180.920
[
formerly
40
CFR
§
180.100(
d)]
are
exempted
from
the
requirement
of
a
tolerance
when
used
in
accordance
with
good
agricultural
practice
as
inert
(
or
occasionally
active)
ingredients
in
pesticide
formulations
applied
to
growing
crops
only.
2.
Residues
listed
in
40
CFR
§
180.930
[
formerly
40
CFR
§
180.100(
e)]
are
exempted
from
the
requirement
of
a
tolerance
when
used
in
accordance
with
good
agricultural
practice
as
inert
(
or
occasionally
active)
ingredients
in
pesticide
formulations
applied
to
animals.

Codex/
International
Harmonization
There
are
no
Codex
maximum
residue
limits
(
MRLs)
for
sodium
chlorate.

E.
Regulatory
Rationale
The
following
is
a
summary
of
the
rationale
for
managing
risks
associated
with
the
use
of
sodium
chlorate
for
sodium
chlorate
products
to
be
eligible
for
reregistration.
Where
labelling
revisions
are
warranted,
specific
language
is
set
forth
in
Table
28
of
Section
V.

1.
Human
Health
Risk
Management
a.
Dietary
(
Food)
Risk
Mitigation
Acute
Dietary
(
Food)
Risk
No
acute
dietary
endpoint
was
selected
for
sodium
chlorate,
because
effects
attributable
to
a
single
dose
were
not
seen
in
the
available
data.
Therefore,
dietary
acute
risk
is
not
of
concern
to
the
Agency,
and
no
mitigation
measures
are
required
to
address
acute
risk.

Chronic
Dietary
(
Food)
Risk
The
chronic
dietary
risk
assessment
for
food
only
is
below
the
Agency's
level
of
concern
(
LOC)
for
the
general
US
population
and
all
population
subgroups.
The
most
highly
exposed
population
subgroup,
children
1­
2
years
of
age,
was
at
28%
of
the
chronic
Population
Adjusted
Dose
(
cPAD).
Since
this
is
less
than
100%
of
the
cPAD,
no
mitigation
is
needed.
47
b.
Residential
Risk
Mitigation
All
residential
(
non­
occupational)
handler
and
post­
application
risk
estimates
for
inorganic
chlorates,
as
active
or
inert
ingredients
in
conventional
pesticide
products
used
in
residential
environments,
are
below
the
Agency's
LOC
(
i.
e.,
MOEs
are
greater
than
the
LOC
of
100).
The
handler
inhalation
MOEs
ranged
from
370
to
710,000.
The
post­
application
combined
MOE
(
for
inert
ingredients)
was
23,000
for
all
potential
routes
of
exposure
to
children;
therefore,
no
residential
mitigation
is
necessary.

c.
Aggregate
Risk
Mitigation
As
discussed
in
Section
III
of
this
RED,
aggregate
risk
refers
to
the
combined
risk
from
food,
drinking
water,
and
residential
exposures.
Aggregate
risk
can
result
from
one­
time
(
acute),
short­
term
and/
or
chronic
exposures.

Acute
Aggregate
Risk
For
sodium
chlorate,
acute
aggregate
risk
was
not
assessed,
because
effects
attributable
to
a
single
dose
were
not
seen
in
the
available
data.
Therefore,
acute
aggregate
risk
is
not
of
concern
to
the
Agency.

Short­
Term
Aggregate
Risk
Short­
term
aggregate
risk
was
quantitatively
assessed
for
adults
only,
using
the
highest
exposure
scenario
(
inhalation
exposure
while
applying
granules
by
hand)
resulting
in
an
MOE
of
324.
Short­
term
aggregate
risk
for
children
was
qualitatively
assessed
and
not
of
concern
to
the
Agency
because
the
short­
term
residential
risk
to
children
from
the
use
of
sodium
chlorate
as
an
inert
is
minimal
(
MOE
of
23,000).
All
short­
term
aggregate
risks
are
below
the
Agency's
LOC
(
i.
e.,
MOEs
are
greater
than
100);
therefore,
no
mitigation
is
necessary.

Chronic
Aggregate
Risk
Since
no
chronic
residential
(
non­
dietary)
exposure
scenarios
have
been
identified
for
sodium
chlorate,
the
chronic
aggregate
risk
assessment
considers
exposure
only
through
food
and
drinking
water.
The
Agency
believes
there
is
no
chronic
risk
of
concern,
for
the
US
general
population
or
any
subpopulation
group,
for
the
reasons
described
below.

The
chronic
dietary
(
water
only)
risk
assessment
for
chlorate
in
drinking
water,
using
the
highest
annual
average
concentration
from
ICR
data
of
0.69
mg/
L,
is
below
the
Agency's
level
of
concern
for
the
general
US
population
and
all
subgroups
except
all
infants
<
1
year
of
age.
The
highest
exposed
population
subgroup,
all
infants
<
1
year
of
age,
was
159%
of
the
cPAD.
Using
the
90th
percentile
annual
average
concentration
of
0.24
mg/
L,
the
chronic
dietary
(
water
only)
risk
for
all
infants
<
1
year
of
age
was
<
55%
of
the
cPAD;
using
the
median
annual
average
concentration
estimated
at
0.11
mg/
L,
estimated
chronic
risk
from
drinking
water
was
25%
of
the
cPAD.
The
contribution
of
exposure
from
food
sources
increases
total
dietary
risk
(
food
+
drinking
water)
to
174%
of
the
cPAD
for
infants
<
1
year
of
age
at
the
highest
annual
average,
48
but
remains
below
EPA's
level
of
concern
at
the
90th
percentile
(
70%
of
the
cPAD).

Data
on
the
occurrence
of
chlorate
ion
in
drinking
water
were
available
from
two
primary
sources:
the
Information
Collection
Rule
(
ICR)
Auxiliary
1
Database,
Version
5.0,
and
the
AwwaRF
research
study
on
the
control
of
chlorate
ion
in
hypochlorite
solutions.
The
most
extensive
data
are
from
the
ICR
where
source
water
and
drinking
water
were
monitored
for
chlorate
ion
between
July
1997
and
December
1998.
Water
systems
serving
a
population
of
at
least
100,000
were
required
to
monitor
for
chlorate
ion
at
treatment
plants
using
chlorine
dioxide
or
hypochlorite
solutions
in
the
treatment
process.
Although
the
ICR
water
systems
represent
roughly
one
percent
of
the
total
number
of
drinking
water
systems
in
the
United
States,
these
systems
serve
almost
60%
of
the
population.
Under
the
ICR,
plants
using
chlorine
dioxide
collected
monthly
samples
of
the
source
water
entering
the
plant,
the
finished
water
leaving
the
plant,
and
at
three
sample
points
in
the
distribution
system
(
near
the
first
customer,
an
average
residence
time,
and
a
maximum
residence
time).
Samples
were
taken
throughout
the
distribution
systems
for
plants
using
chlorine
dioxide,
since
the
concentration
of
chlorate
is
expected
to
change
within
the
system
due
to
the
conversion
of
chlorine
dioxide
to
chlorate
that
occurs
in
the
presence
of
chlorine.
Plants
using
hypochlorite
solutions
were
required
to
collect
quarterly
samples
of
the
water
entering
and
leaving
the
plant.

The
AwwaRF
data
consists
of
samples
collected
in
1993
by
111
water
treatment
plants
using
hypochlorite.
The
majority
of
the
systems
in
the
AwwaRF
project
serve
populations
less
than
100,000,
and
a
large
subset
of
those
serve
populations
less
than
10,000.
Samples
of
source
water,
hypochlorite
solution,
and
finished
drinking
water
from
111
of
water
systems
were
analyzed
for
chlorate.
Only
one
set
of
samples
was
collected
for
each
system,
and
samples
were
not
collected
at
plants
using
chlorine
dioxide.
Furthermore,
the
background
information
on
the
111
water
systems
that
participated
in
the
project
was
not
linked
to
the
samples
they
provided;
therefore,
the
chlorate
concentrations
can
not
be
directly
related
to
the
size
of
the
water
system
or
type
of
hypochlorite
solution
in
use.

The
AwwaRF
samples
were
typically
found
to
have
higher
concentrations
of
chlorate
than
the
samples
collected
from
the
larger
ICR
systems.
The
difference
in
chlorate
concentrations
could
be
the
result
of
a
number
of
factors,
such
as:
1)
The
AwwaRF
data
represents
a
single
point
in
time,
while
the
ICR
data
reflects
an
average
over
18
months;
2)
most
of
the
AwwaRF
samples
were
collected
from
utilities
that
served
populations
of
less
that
100,000,
while
all
of
the
ICR
samples
were
from
utilities
serving
at
least
100,000;
and
3)
hypochlorite
treatment
plant
practices
may
have
changed
between
when
the
AwwaRF
samples
were
collected
(
1993)
and
the
ICR
samples
were
collected
(
1997­
1998).
When
the
AwwaRF
study
was
conducted,
utilities
were
just
becoming
aware
of
the
formation
of
chlorate
ion
in
hypochlorite
solutions.
The
AwwaRF
project
was
funded
in
order
to
provide
water
treatment
facilities
with
information
on
how
to
minimize
the
formation
of
chlorate
byproduct;
it
is
possible
that
facilities
consequently
revised
their
treatment
practices.

The
ICR
Database
was
considered
the
more
appropriate
source
for
estimating
exposure
averages
from
individual
water
treatment
plants,
primarily
because
the
AwwaRF
study
is
a
less
robust
data
set
consisting
of
only
one
sample
per
utility,
whereas
the
ICR
database
collected
multiple
samples
over
an
18
month
period,
from
plants
using
both
hypochlorite
and
chlorine
49
dioxide.
Both
the
AwwaRF
study
and
the
ICR
data
reveal
high
concentrations
of
chlorate
ion
to
be
a
local
situation
affecting
a
relatively
small
number
of
systems.
Of
the
ICR
data
set,
only
four
water
treatment
plants
had
average
chlorate
ion
concentrations
that
exceeded
the
Agency's
level
of
concern
(
i.
e.,
370
ppb
or
0.37
mg/
L,
for
the
infant
subpopulation)
including
one
treatment
plant
serving
218,000
people
that
had
the
highest
annual
average
(
0.69
mg/
L).
Of
the
four
plants
that
exceeded,
two
treatment
plants
used
chlorine
dioxide,
and
two
used
hypochlorite.
The
total
number
of
people
served
by
the
four
water
treatment
plants
exceeding
0.37
mg/
L
represents
0.5%
of
the
ICR
population,
or
621,000
people.
All
three
exposure
ranges
(
highest
average,
90th
percentile,
and
median)
are
presented
in
Section
III.
Only
the
"
highest
average"
exposures
resulted
in
potential
chronic
risk
estimates
that
were
above
the
Agency's
LOC,
and
only
for
infants.
Over
99%
of
the
ICR
population
receives
finished
water
below
the
Agency's
LOC
of
0.37
mg/
L.

The
chlorate
ion
(
ClO
3
­)
is
a
disinfection
byproduct
(
DBP)
of
water
treatment
which
can
be
formed
during
the
on­
site
generation
of
chlorine
dioxide
(
ClO
2
­),
the
decomposition
of
chlorine
dioxide
in
the
water
treatment
system,
the
decomposition
of
hypochlorite
(
OCl­)
during
storage,
and
the
interaction
of
chlorite
ion
and
free
chlorine.
Treatment
of
public
water
supplies
is
necessary
to
kill
pathogens
that
may
exist
in
the
drinking
water,
such
as
cholera,
typhoid,
and
dysentery.
Outbreaks
of
these
diseases
decreased
significantly
when
disinfection
of
the
water
systems
was
introduced
in
the
early
1900s.
While
there
are
many
important
public
functions
of
water
treatment,
the
Agency
is
taking
steps
to
limit
the
exposure
of
chlorate
ion
as
a
DBP
to
the
public.

In
order
to
help
reduce
potential
exposure
to
chlorate,
the
Agency's
Office
of
Pesticide
Programs
(
OPP),
in
conjunction
with
the
Office
of
Water
(
OW),
is
working
with
the
American
Water
Works
Association
(
AWWA),
the
Chlorine
Institute,
and
individual
water
communities
to
provide
community
water
systems
with
information
on
Best
Management
Practices
(
BMPs)
for
use
in
drinking
water
treatment.
BMPs
may
include
measures
such
as
production
modifications,
operational
changes,
materials
substitution,
materials
and
water
conservation,
and
other
such
measures.
For
example,
water
systems
that
use
hypochlorite
solutions
can
minimize
the
levels
of
chlorate
ion
by
purchasing
high
quality
hypochlorite
solutions
and
through
careful
storage
during
use.
While
decomposition
of
hypochlorite
solutions
cannot
be
avoided,
the
rate
of
decomposition
can
be
managed.
Among
the
major
factors
affecting
stability
are
the
following:
concentration
of
the
hypochlorite
solution,
temperature
of
the
solution,
pH
of
the
solution,
and
exposure
to
light
sources.
The
pH
of
the
solution
should
be
in
the
12
to
13
range
to
minimize
decomposition.
Hypochlorite
solutions
should
be
protected
from
high
temperatures
and
sunlight,
and
storage
time
should
be
minimized,
both
from
the
time
of
manufacture
to
delivery,
and
from
the
time
of
delivery
to
use.
The
solutions
can
also
be
diluted
to
control
decomposition
as
long
as
the
proper
pH
is
maintained
and
high
quality
dilution
water
is
used.
The
primary
ways
in
which
water
systems
using
chlorine
dioxide
can
control
the
levels
of
chlorate
in
the
finished
water
is
through
high
efficiency
operation
of
their
chlorine
dioxide
generators
and
by
reducing
chlorite
ion
concentrations
prior
to
the
addition
of
free
chlorine.
The
BMPs
could
also
include
additional
training
of
the
water
systems
employees
on
the
proper
handling
of
these
chemicals.

The
Agency
believes
that
sodium
chlorate
does
not
constitute
a
risk
of
concern
to
the
general
population
or
any
population
subgroups,
since
the
LOC
exceedances
are
associated
with
50
a
small
number
of
water
treatment
facilities
and
inappropriate
treatment
practices.
Furthermore,
the
Agency
anticipates
that
the
community
water
system
outreach
strategy
previously
discussed
will
greatly
reduce
potential
drinking
water
byproduct
exposure.

d.
Occupational
Risk
Mitigation
With
the
consideration
of
mitigation
measures
proposed
by
registrants
and
the
use
of
engineering
controls
(
enclosed
cockpits
or
cabs),
all
occupational
handler
risks
for
the
use
of
inorganic
chlorates
as
an
active
or
inert
ingredient
in
conventional
pesticides
are
below
the
Agency's
LOC
(
i.
e.,
MOEs
are
greater
than
the
LOC
of
100).
For
sodium
chlorate,
occupational
exposure
durations
are
short­
(
1­
30
days)
and
intermediate
term
(
1­
6
months)
only.
Long­
term
(>
6
months)
exposure
is
not
expected
based
on
the
use
pattern
for
sodium
chlorate.
Postapplication
dermal
and
inhalation
exposures
are
negligible
due
to
the
chemical's
physical
and
chemical
characteristics
as
an
inorganic
salt.
No
significant
amount
of
sodium
chlorate
is
expected
to
be
absorbed
through
the
skin
and
the
vapor
pressure
is
negligible;
therefore,
a
postapplication
exposure
assessment
was
not
conducted.

Antimicrobial
Uses
of
Sodium
Chlorate
Risks
to
handlers
treating
water
systems
are
below
the
Agency's
LOC;
therefore,
no
mitigation
measures
are
necessary.

Agricultural
Uses
of
Sodium
Chlorate
With
the
exception
of
aerial
applications,
for
which
enclosed
cockpits
are
required,
the
handler
and
flagger
MOEs
for
sodium
chlorate's
agricultural
uses
are
below
the
Agency
LOC
at
baseline
level
of
protection
(
long
sleeve
shirt,
long
pants,
shoes,
and
socks).
MOEs
range
from
190
(
mixing/
loading
liquids
for
aerial
application
on
cotton,
corn,
et
al.)
to
3600
(
mixing/
loading
liquids
for
groundboom
application
on
ornamental
gourds
and
cucurbits).
Further,
the
maximum
application
rate
for
use
on
cotton
will
be
reduced
from
7.5
lbs
ai/
A
to
6
lbs
ai/
A,
with
a
limitation
of
one
application
(
except
for
California,
where
two
applications
will
be
allowed).
No
additional
mitigation
is
required
for
occupational
risk
resulting
from
the
agricultural
uses
of
sodium
chlorate.

Non­
agricultural
Uses
of
Sodium
Chlorate
The
Agency's
review
of
sodium
chlorate
labels,
in
addition
to
discussions
with
registrants,
indicates
that
the
current
non­
agricultural
use
labels
are
not
reflective
of
actual
use
practices.
The
non­
agricultural
use
labels
currently
allow
for
larger
application
rates
than
are
necessary
for
efficacy,
as
well
as
allow
for
unlimited
treatment
areas,
although
sodium
chlorate's
non­
agricultural
formulations
are
typically
used
as
spot
treatments.

Mitigation
measures
for
sodium
chlorate's
non­
agricultural
uses
to
be
included
on
product
labels
will
reduce
risk
from
the
occupational
and
ecological
exposures
to
sodium
chlorate.
The
registrants
have
agreed
to
the
following
non­
agricultural
use
mitigation
measures
for
sodium
chlorate:
51
 
All
non­
agricultural
uses
will
be
limited
to
spot
treatments
only
(
with
the
exception
of
the
granular
formulation
for
use
under
asphalt,
although
this
use
will
be
limited
to
an
8000
ft2
treatment
area).
The
uses
limited
to
spot
treatments
include,
but
are
not
limited
to:
building
perimeters
(
including
farm
buildings),
driveways,
parking
lots,
fence
rows,
military
installations,
pipelines,
railroads,
lumberyards,
industrial
sites
(
transformers,
generators,
utility
poles,
etc.),
tennis
court
perimeters,
picnic
areas,
bleachers,
cemeteries,
fuel
tanks,
airport
runways,
helo
pads,
wood
decks,
guard
rails,
highway
medians,
sidewalks/
walkways,
vacant
lots,
fire
hydrants,
recreational
areas,
and
other
similar
areas.

 
Use
on
rights­
of­
way
and
ditch
banks
will
be
cancelled.

 
The
label
will
specify
a
maximum
application
rate
of
0.9
lb
ai/
100
ft2
The
Agency
generally
converts
application
rates
to
a
per
acre
basis
for
assessment
purposes;
therefore,
the
rate
of
0.9
lb
ai/
100
ft2
is
referred
to
as
392
lb
ai/
A
in
this
document.
However,
because
all
non­
agricultural
uses
will
be
limited
to
spot
treatment
applications
only,
all
392
pounds
of
a.
i.
will
not
be
applied
on
any
one
given
acre.
Assuming
only
one
acre
is
considered
for
treatment,
sodium
chlorate
can
only
be
applied
to
up
to
8000
ft2,
which
equates
to
up
to
approximately
78
lbs
ai
being
applied
to
any
given
acre.
It
is
assumed
that
more
than
one
acre
will
be
treated.

Risk
calculations
have
been
developed
to
better
represent
the
current,
actual
use
pattern
for
sodium
chlorate,
and
occupational
risk
was
reassessed
based
on
the
revised
use
pattern
discussed
above
(
i.
e.,
application
rates,
target
sites,
and
amount
treated).
Following
is
a
summary
of
the
Inorganic
Chlorates:
Addendum
to
the
Occupational
and
Residential
Exposure
Assessment
for
the
Reregistration
Eligibility
Decision
(
RED)
Document,
dated
May
18,
2006.

All
data,
factors,
and
assumptions
used
in
the
addendum
are
the
same
as
those
used
in
the
previous
occupational
risk
assessment.
These
include,
but
are
not
limited
to:

 
body
weight
(
70
kg
representing
adult
handlers);
 
toxicological
endpoints
(
short­/
intermediate­
term
oral
NOAEL
of
30
mg/
kg/
day)
and
uncertainty
factors
(
Level
of
Concern
(
LOC)
for
the
MOE
is
100);
 
application
rates
(
in
lb
ai/
A
 
presented
as
a
range
to
encompass
the
various
registered
products);
and,
 
unit
exposures
(
from
PHED
and/
or
ORETF
database,
both
of
which
have
undergone
appropriate
review
by
the
Human
Studies
Review
Board).

However,
factors
regarding
application
equipment
used
and
daily
area
treated
were
revised
based
on
updated
use
pattern
information
and
proposed
product
label
revisions.
The
previous
assessment,
summarized
in
Section
III,
was
based
on
applications
with
larger,
industrial
equipment
such
as
tractor
spreaders
or
groundboom
sprayers.
As
a
result
of
mitigation
measures
agreed
to
by
the
technical
registrants,
sodium
chlorate
applications
to
non­
agricultural
areas
(
i.
e.,
building
perimeters,
ditch
banks,
bleachers,
airport
runways,
vacant
lots,
fire
hydrants,
or
as
a
pre­
paving
treatment)
will
be
limited
to
"
handheld"
equipment
such
as
rotary
spreaders
and
52
pump
or
power
sprayers.
In
addition,
the
standard
Agency
assumptions
for
the
amount
applied
per
work
day
is
based
on
the
application
equipment
used
to
determine
exposure
and
risk.
Since
submitted
information
indicates
that
no
more
than
8,000
ft2
of
an
acre
(
approximately
20%)
will
be
treated
with
sodium
chlorate,
the
Agency
has
adjusted
the
standard
assumptions
for
acres
treated
per
day
to
reflect
this
spot
treatment­
type
scenario.

Based
on
the
revised
assumptions
for
the
daily
area
treated
and
on
application
methods
suitable
for
spot
treatments
(
low­
pressure
handwand
sprayers,
belly
grinders,
push­
type
spreaders),
the
risks
for
all
non­
agricultural
uses,
even
at
the
currently
labeled
application
rate
(
523
lbs
ai/
A
instead
of
392
lb
ai/
A),
are
below
the
Agency
LOC.
The
higher
application
rate
of
523
lb
ai/
A
was
used,
because
at
the
time
the
Inorganic
Chlorates:
Addendum
to
the
Occupational
and
Residential
Exposure
Assessment
for
the
Reregistration
Eligibility
Decision
(
RED)
Document,
dated
May
18,
2006,
was
prepared,
the
392
lb
ai/
A
maximum
application
rate
mitigation
measure
was
not
yet
finalized.
The
mitigation
measures
outlined
above
reduce
the
occupational
risk
from
all
of
sodium
chlorate's
non­
agricultural
uses
to
below
the
Agency's
level
of
concern
at
baseline
level
of
protection
(
long
sleeve
shirt,
long
pants,
shoes,
and
socks).
The
risks
based
on
the
revised
non­
agricultural
use
patterns
for
sodium
chlorate
are
summarized
in
Table
26
below.

Table
26:
Sodium
Chlorate:
Short­
and
Intermediate­
Term
Occupational
Inhalation
Exposure
Exposure
Scenario
Daily
Area
Treated
(
Acres/
day)
Crop/
Target
Application
Rate
(
lbs
ai/
Acre)
a
Inhalation
MOE
(
at
baseline)

Mixer/
Loader/
Applicators
&
Loader/
Applicators
523
330
Mixing/
Loading/
Applying
liquids
with
a
lowpressure
handwand
sprayer
0.4
Industrial/
Non­
Crop
Sites
132
1300
523
2200
M/
L/
A
liquids
with
a
handgun
sprayer
1
Industrial/
Non­
Crop
Sites
132
8800
523
320
240
710
L/
A
granules
with
a
belly
grinder
0.2
Industrial/
Non­
Crop
Sites
161
1100
523
550
240
1200
L/
A
granules
with
a
pushtype
spreader
1
Industrial/
Non­
Crop
Sites
161
1800
a.
Application
rate
will
be
reduced
to
0.9
lb
ai/
100
ft2
(
392
lb
ai/
A).

2.
Non­
Target
Organism
(
Ecological)
Risk
Management
Chlorate
is
a
strong
oxidizer
and
may
be
reduced
to
other
chemically
related
species
under
some
environmental
conditions.
The
extent
and
rate
to
which
this
occurs
will
depend
on
the
redox
chemical
species
(
including
organic
matter)
in
the
water
or
soil.
Extensive
spatial
and
53
temporal
variability
is
expected
for
the
reactions
of
chlorate
in
the
environment.
However,
the
currently
available
simulation
models
do
not
allow
for
a
quantitative
evaluation
of
the
potential
exposure
levels
of
each
the
reduced
products
of
chlorate
(
i.
e.,
speciation
and
predominance)
and
how
fast
these
chemical
species
may
form.
Therefore,
there
is
a
high
degree
of
uncertainty
in
the
ecological
exposure
and
risk
assessment.
This
is
important
because
a
reduction
product
of
chlorate
(
chlorite)
is
expected
to
be
more
toxic
to
most
aquatic
and
terrestrial
species,
particularly
aquatic
invertebrates.

a.
Terrestrial
Organisms
1.
Birds
and
Mammals
EPA's
screening­
level
risk
assessment,
based
on
currently
labelled
maximum
application
rates,
for
both
agricultural
and
non­
agricultural
uses
for
sodium
chlorate,
suggests
potential
acute
and
chronic
risk
for
birds
Avian
Acute
Risk
Avian
acute
risk
was
not
calculated,
since
no
mortality
or
signs
of
toxicity
were
observed
in
the
submitted
subacute
or
acute
toxicity
studies
at
concentrations
that
are
above
the
limit
for
these
types
of
studies;
therefore,
acute
risk
to
birds
is
not
expected.
However,
the
Agency
cannot
preclude
acute
or
subacute
risk
from
the
non­
agricultural
uses.
Some
labels
have
maximum
application
rates
up
to
1032
lbs
ai/
A,
and
the
ecological
assessment
for
risk
from
nonagricultural
uses
was
based
on
rates
ranging
from
52
to
523
lbs
ai/
A,
with
corresponding
EECs
from
12,500
and
125,000
ppm,
respectively.
These
EECs
are
approximately
2.5
to
25­
fold
higher
than
the
highest
concentration
tested
in
the
subacute
bird
toxicity
studies.
The
nonagricultural
use
mitigation
outlined
above,
including
the
reduction
of
the
maximum
application
rate
to
392
lbs
ai/
A,
and
a
limitation
to
spot
treatments
only
(
except
for
use
under
asphalt,
although
this
use
is
limited
to
no
more
than
an
8000
ft2
area).
Reducing
the
maximum
application
rate
from
520
lbs
ai/
A
to
392
lbs
ai/
A
will
reduce
the
estimated
environmental
concentrations
of
chlorate
by
approximately
25%.
Further,
to
the
extent
that
there
is
any
potential
acute
risk
to
birds
from
the
non­
agricultural
uses,
the
fact
that
these
uses
will
result
in
small
contiguously
treated
areas
could
limit
avian
exposure.

Avian
Chronic
Risk
Maximum
chronic
RQs,
based
on
EECs
derived
with
90th
percentile
residue
estimates
from
the
Kenaga
nomogram,
exceed
the
Agency's
avian
LOC
of
1.0
for
all
agricultural
uses
assessed
for
birds
eating
short
grass,
tall
grass,
broadleaf
forage,
and
small
insects.
Chronic
RQs
based
on
EECs
derived
with
mean
residue
estimates
from
the
Kenaga
nomogram,
although
not
presented
in
Section
III,
would
be
approximately
three
times
lower
for
any
single
application
of
sodium
chlorate.
The
highest
agricultural
use
chronic
RQ
was
11
(
chili
peppers/
white,
Irish
potatoes
and
the
short
grass
food
category).
The
second
highest
RQs
were
for
cotton
(
ranging
from
10.0
for
the
short
grass
food
category,
to
0.63
for
fruits,
pods,
seeds,
and
small
insects).
Cotton
is
also
by
far
the
most
common
agricultural
use
of
sodium
chlorate,
with
approximately
1,900,000
lbs
ai
applied
annually.
54
To
address
the
chronic
risk
to
birds
from
use
on
cotton,
the
maximum
application
rate
will
be
reduced
from
7.5
lbs
ai/
A
to
6
lbs
ai/
A,
and
applications
will
be
limited
to
a
single
applications
in
all
states
except
California,
where
a
second
application
will
be
allowed.
This
mitigation
measure
will
reduce
chronic
risk
to
birds
from
use
on
cotton
by
approximately
onehalf
with
RQs
ranging
from
5.31
(
on
the
short
grass
food
category),
to
0.33
(
on
fruits,
pods,
seeds,
and
small
insects)
for
all
states
except
California.
In
California,
the
chronic
avian
RQs
based
on
the
reduced
maximum
application
rate
of
6
lbs
ai/
A,
and
two
applications,
will
be
reduced
to
a
range
of
8.25
(
on
the
short
grass
food
category)
to
0.52
(
on
fruits,
pods,
seeds,
and
small
insects).

Chronic
avian
RQs
for
sodium
chlorate
were
based
on
a
NOAEC
of
271
ppm
from
the
bobwhite
quail
chronic
reproductive
toxicity
test.
However,
maximum
EECs
for
a
majority
of
the
uses
and
classes
of
food
items
were
also
higher
than
the
LOAEC
in
bobwhite
quail
of
964
ppm.
At
the
LOAEC,
reproductive
effects
occurred,
including
a
67%
reduction
in
eggs
laid
and
64%
reduction
in
number
of
hatchlings
per
egg
laid.
Therefore,
if
actual
exposure
is
equivalent
to
the
maximum
values
calculated
with
the
T­
REX
model,
there
is
a
greater
certainty
that
frank
reproductive
effects
in
birds
might
occur.

However,
the
duration
of
exposure
needed
to
produce
reproductive
effects
in
birds
is
an
uncertainty.
This
uncertainty
is
significant
in
the
case
of
sodium
chlorate,
because
as
a
broadspectrum
herbicide,
its
toxic
effects
on
plants
are
visible
within
several
days.
Since
the
vegetation
in
the
treated
area
will
die,
it
is
uncertain
whether
or
not
this
vegetation
will
be
attractive
to
birds
as
a
feed
item
long
enough
for
the
chronic
effects
to
occur.

Chronic
RQs
were
not
calculated
for
sodium
chlorate's
non­
agricultural
uses.
However,
based
on
the
high
application
rates
and
resulting
high
potential
EECs,
risks
from
sodium
chlorate's
non­
agricultural
uses
could
be
considerably
higher
than
those
described
in
Section
III
for
the
agricultural
uses.
The
non­
agricultural
use
mitigation
outlined
above,
including
a
reduction
in
the
maximum
labeled
application
rate
to
0.9
lbs
ai/
100
ft2
(
392
lbs
ai/
A),
would
reduce
the
EECs
of
chlorate
by
approximately
25%
in
the
areas
treated.
Furthermore,
the
limitation
of
most
non­
agricultural
uses
to
spot
treatments
only
is
expected
to
reduce
the
likelihood
that
a
terrestrial
organism
will
come
into
contact
and
consume
all
of
its
diet
from
a
treated
area.
However,
RQs
still
exceed
the
chronic
LOC
for
birds
(
1.0).
See
the
Analysis
of
proposed
changes
to
sodium
chlorate's
application
rates
and
maximum
treated
area
on
potential
ecological
risks
presented
in
EFED's
reregistration
eligibility
decision
(
RED)
document,
dated
June
13,
2006
for
further
detail.

Mammalian
Acute
Risk
Acute
RQs
were
not
calculated
for
mammals.
The
LD50
from
a
core
acute
oral
toxicity
study
in
rats
was
>
5000
mg/
kg­
bw.
In
this
study,
10%
(
1/
10)
of
the
rats
administered
5000
mg/
kg
died.
Mortality
was
not
observed
at
any
other
dose.
Therefore,
the
data
were
not
sufficient
to
allow
for
characterization
of
the
dose­
response
relationship
and
the
proximity
of
the
LD50
to
5000
mg/
kg­
bw
is
uncertain.
Although
RQs
were
not
calculated
for
mammals,
Tables
17,
18
and
19
in
Section
III
present
a
comparison
of
the
body
weight
adjusted
LD50s
to
EECs
for
55
agricultural
spray,
and
the
non­
agricultural
spray
and
granular,
formulations,
respectively.
These
ratios
can
be
used
to
estimate
high­
end
risk
to
exposed
mammals.
Risk
quotients
would
be
lower
than
the
values
in
Section
III.

For
sodium
chlorate's
agricultural
uses,
all
of
the
mammalian
acute
risk
estimates
are
below
the
Agency's
acute
and
endangered
species
LOC
of
1.0
and
0.1,
respectively,
with
the
exception
of
small
mammals
eating
short
grass.
The
highest
exceedence
is
for
15
gram
mammals
eating
short
grass
(
risk
ratio
=
0.26);
therefore,
no
mitigation
is
necessary.

For
sodium
chlorate's
non­
agricultural
uses,
the
ratios
indicate
a
potential
acute
concern
to
mammals
for
both
spray
and
granular
formulations,
with
the
highest
ratios
calculated
for
small
mammals
(
ratios
=
11
and
33
for
spray
and
granular
formulations,
respectively).
While
the
ratios
presented
in
Section
III
suggest
that
there
could
be
acute
risk
to
mammals
of
all
sizes
that
forage
in
the
area
where
sodium
chlorate
is
applied
to
non­
agricultural
use
sites,
the
risk
was
likely
over­
estimated,
since
an
LD50
has
not
been
established.
Furthermore,
as
previously
explained,
a
reduction
in
the
maximum
application
rate
for
the
non­
agricultural
uses
to
392
lbs
ai/
A
would
reduce
the
EEC's
of
chlorate
in
treated
areas
by
approximately
25%.
Limitation
of
the
treatments
to
spot
treatments
only
would
be
expected
to
further
reduce
the
likelihood
that
a
terrestrial
organism
will
come
into
contact
and
consume
all
of
its
diet
from
that
area.

Mammalian
Chronic
Risk
For
mammals,
the
Agency
typically
evaluates
the
mammalian
reproductive
effects
for
exposures
greater
than
30
days.
The
interpretation
of
the
effects
seen
in
the
2­
generation
rat
reproduction
toxicity
study,
used
to
derive
the
mammalian
reproduction
toxicity
endpoint
for
sodium
chlorate,
is
difficult
in
this
respect.
While
effects
were
observed
at
70
mg/
kg­
bw
and
above,
the
effects
are
not
clearly
associated
with
reduced
reproductive
success
or
survival.
The
mammalian
reproductive
NOAEC
is
based
on
the
highest
dose
tested
in
this
study
(
500
mg/
kgbw
although
no
toxic
or
reproductive
effects
were
observed
at
this
level.
Therefore,
the
NOAEC
could
be
higher
than
500
mg/
kg­
bw,
which
would
result
in
lower
mammalian
reproduction
risk
estimates.
However,
the
Agency
calculated
risk
ratios
based
on
the
500
mg/
kgday
NOAEL
as
a
conservative
estimate
of
risk,
as
presented
in
Section
III.
For
the
agricultural
uses
of
sodium
chlorate,
the
chronic
mammalian
LOC
of
1.0
was
only
slightly
exceeded
for
the
smallest
weight
classes
of
mammals
for
most
food
items
and
the
largest
weight
class
of
mammals
feeding
on
short
grass
(
RQs
range
from
2.6
to
0.07).
The
mitigation
measures
previously
outlined
for
sodium
chlorate
use
on
cotton
(
maximum
application
rate
reduced
from
7.5
lbs
ai/
A
to
6
lbs
ai/
A,
with
the
limitation
of
a
single
application,
except
in
California,
where
a
second
application
will
be
allowed),
will
further
reduced
chronic
mammalian
risk.
Furthermore,
based
on
the
lack
of
observed
reproductive
effects
in
the
chronic
study
and
the
slight
LOC
exceedances
for
agricultural
uses,
the
Agency
does
not
anticipate
a
chronic
risk
of
concern
to
mammals
from
these
uses.

As
with
the
agricultural
uses,
mammalian
reproduction
RQs
were
not
calculated
for
sodium
chlorate's
non­
agricultural
uses.
However,
the
higher
application
rates
for
the
nonagricultural
uses,
and
the
resulting
higher
EECs,
suggest
that
the
risk
for
these
uses
would
be
higher
than
the
risk
estimates
presented
for
the
agricultural
uses.
Note
that
the
mammalian
56
reproduction
RQs
for
the
agricultural
uses
of
sodium
chlorate,
presented
in
Section
III,
are
a
conservative
estimate
of
risk.
Furthermore,
as
previously
explained,
to
reduce
risk
from
sodium
chlorate's
non­
agricultural
uses,
the
maximum
application
rate
will
be
reduced
to
0.9
lb
ai/
100
ft2.
This
mitigation
measure
will
reduce
the
EECs
by
approximately
25%.
In
addition,
the
limitation
to
spot
treatments
will
reduce
the
likelihood
that
mammals
will
come
into
contact
and
consume
all
of
its
diet
from
a
treated
area.
See
the
Analysis
of
proposed
changes
to
sodium
chlorate's
application
rates
and
maximum
treated
area
on
potential
ecological
risks
presented
in
EFED's
reregistration
eligibility
decision
(
RED)
document,
dated
June
13,
2006,
for
further
detail.

2.
Non­
Target
Insects
EPA
currently
does
not
estimate
RQs
for
terrestrial
non­
target
insects.
In
addition,
the
Agency
has
no
toxicity
data
for
sodium
chlorate.
Therefore,
EPA
will
require
data
to
address
this
uncertainty.

3.
Non­
Target
Terrestrial
Plants
Based
on
chlorate's
non­
selective
mode
of
action
and
lack
of
adequate
toxicity
data,
the
Agency
presumes
risk
to
non­
target
terrestrial
plants
at
levels
above
the
Agency's
level
of
concern
for
all
uses.
The
risks
to
plants
cannot
be
quantified
at
this
time
due
to
lack
of
data;
however,
the
Agency
will
require
data
to
address
this
uncertainty.

b.
Aquatic
Organisms
1.
Fish
There
is
no
acute
risk
of
concern,
from
either
the
agricultural
or
non­
agricultural
uses
of
sodium
chlorate,
to
freshwater
or
estuarine/
marine
fish.
All
risk
ratios
are
less
than
0.05,
which
is
below
the
Agency's
acute
LOC
of
0.5
and
below
the
acute
endangered
species
LOC
of
0.05.
However,
some
data
suggest
that
brown
trout
(
freshwater
fish)
could
be
substantially
more
sensitive
than
other
fish
species
tested
to
chlorate's
toxicity.
It
is
uncertain
if
these
data
are
reliable;
therefore,
the
Agency
will
require
additional
testing
in
brown
trout
to
address
this
area
of
uncertainty.

No
chronic
fish
toxicity
studies
are
available
to
allow
for
chronic
risk
to
fish
to
be
quantified.
Therefore,
the
Agency
will
require
data
to
address
this
uncertainty.

2.
Aquatic
Invertebrates
For
freshwater
invertebrates,
acute
RQs
are
below
the
acute
LOC
of
0.5
and
the
endangered
species
acute
LOC
of
0.05,
for
both
agricultural
and
non­
agricultural
uses
of
sodium
chlorate.
Therefore,
acute
risk
to
freshwater
invertebrates
is
not
of
concern
to
the
Agency,
and
no
mitigation
is
required.

For
saltwater
invertebrates,
the
acute
risk
ratios
for
sodium
chlorate's
agricultural
and
nonagricultural
uses
were
below
the
Agency's
acute
LOC
of
0.5,
in
addition
to
the
endangered
species
acute
LOC
of
0.05
(
highest
ratio
=
0.04
for
non­
agricultural
uses).
Therefore,
acute
risk
57
to
saltwater
invertebrates
is
not
of
concern
to
the
Agency.

Chronic
risk
to
invertebrates
(
freshwater
and
saltwater)
was
not
assessed,
since
treatmentrelated
effects
were
not
observed
at
any
concentration
in
available
studies.

3.
Aquatic
Plants
For
non­
endangered
aquatic
plants,
the
Agency's
LOC
of
1.0
was
not
exceeded
for
either
the
agricultural
or
nonagricultural
uses
of
sodium
chlorate
(
highest
RQ
=
0.91
for
nonagricultural
uses).
Therefore,
risk
to
non­
endangered
aquatic
plants
is
not
of
concern
to
the
Agency.

For
endangered
aquatic
plants,
the
Agency's
LOC
of
1.0
was
not
exceeded
for
sodium
chlorate's
agricultural
uses
(
highest
RQ
=
0.29),
but
the
LOC
was
exceeded
for
sodium
chlorate's
nonagricultural
uses
(
highest
RQ
=
12.6).
However,
the
mitigation
measures
listed
above
for
the
non­
agricultural
uses
of
sodium
chlorate,
including
a
reduction
in
the
application
rate
and
treated
area,
result
in
a
reduction
of
the
endangered
vascular
plant
RQ
from
12.6
to
1.5.
While
this
is
a
significant
improvement,
it
is
still
above
the
Agency's
endangered
plant
LOC
of
1.0.
Furthermore,
because
of
a
lack
of
submitted
data,
there
is
uncertainty
remaining
on
sodium
chlorate's
toxicity
to
aquatic
plants.
The
Agency
will
require
data
to
address
this
area
of
uncertainty.

3.
Summary
of
Mitigation
Measures
The
following
mitigation
measures
are
necessary
for
sodium
chlorate
to
be
eligible
for
reregistration.
These
include
use
restrictions,
voluntary
cancellations
and/
or
use
deletions,
and
personal
protective
equipment.

Agricultural
use
mitigation:

 
Engineering
controls
(
enclosed
cockpits)
for
aerial
applications
on
agricultural
crops.
 
For
cotton,
the
maximum
application
rate
will
be
reduced
from
7.5
lbs
ai/
A
to
6
lbs
ai/
A,
and
applications
will
be
limited
to
a
single
applications
in
all
states
except
California,
where
a
second
application
will
be
allowed.

Non­
agricultural
use
mitigation:

 
All
non­
agricultural
uses
will
be
limited
to
spot
treatments
only
(
with
the
exception
of
the
granular
formulation
for
use
under
asphalt,
although
this
use
will
be
limited
to
an
8000
ft2
treatment
area).
The
uses
limited
to
spot
treatments
include,
but
are
not
limited
to:
building
perimeters
(
including
farm
buildings),
driveways,
parking
lots,
fence
rows,
military
installations,
pipelines,
railroads,
lumberyards,
industrial
sites
(
transformers,
generators,
utility
poles,
etc.),
tennis
court
perimeters,
picnic
areas,
bleachers,
cemeteries,
fuel
tanks,
airport
runways,
helo
pads,
wood
decks,
guard
rails,
highway
medians,
sidewalks/
walkways,
vacant
lots,
fire
hydrants,
recreational
areas,
and
other
similar
areas.
58
 
Use
on
rights­
of­
way
and
ditch
banks
will
be
cancelled.

 
The
label
will
specify
a
maximum
application
rate
of
0.9
lb
ai/
100
ft2.

F.
Other
Labeling
Requirements
To
be
eligible
for
reregistration,
various
use
and
safety
information
will
be
included
in
the
labeling
of
all
end­
use
products
containing
sodium
chlorate.
For
the
specific
labeling
statements
and
a
list
of
outstanding
data,
refer
to
Section
V
of
this
RED
document.

1.
Endangered
Species
Considerations
The
Agency's
screening
level
assessment
results
in
the
determination
that
sodium
chlorate
will
have
no
acute
risks
to
birds,
no
acute
risks
to
fish
(
freshwater
and
estuarine/
marine),
and
no
acute
or
chronic
risks
to
aquatic
invertebrates
(
freshwater
and
estuarine/
marine).

However,
the
preliminary
risk
assessment
for
endangered
species
indicates
that
RQs
exceed
endangered
species
LOCs
for
chronic
risks
to
birds
(
RQs
up
to
11
for
agricultural
uses
and
greater
for
non­
agricultural
uses);
acute
risks
to
mammals
(
RQs
up
to
33);
chronic
risks
to
mammals
(
RQs
up
to
1.2
for
agricultural
uses
and
greater
for
non­
agricultural
uses);
and
risks
to
aquatic
plants
(
RQs
up
to
13).
Risks
could
not
be
calculated
for
terrestrial
plants
and
for
chronic
risks
to
fish;
however,
the
Agency
will
be
requiring
data.

Further,
potential
indirect
effects
to
any
species
dependent
upon
a
species
that
experiences
effects
from
use
of
sodium
chlorate
can
not
be
precluded
based
on
the
screening
level
ecological
risk
assessment.
These
findings
are
based
solely
on
EPA's
screening
level
assessment
and
do
not
constitute
"
may
affect"
findings
under
the
Endangered
Species
Act.

The
Agency
has
developed
the
Endangered
Species
Protection
Program
to
identify
pesticides
whose
use
may
cause
adverse
impacts
on
endangered
and
threatened
species,
and
to
implement
mitigation
measures
that
address
these
impacts.
The
Endangered
Species
Act
(
ESA)
requires
federal
agencies
to
ensure
that
their
actions
are
not
likely
to
jeopardize
listed
species
or
adversely
modify
designated
critical
habitat.
To
analyze
the
potential
of
registered
pesticide
uses
that
may
affect
any
particular
species,
EPA
uses
basic
toxicity
and
exposure
data
developed
for
the
REDs
and
considers
it
in
relation
to
individual
species
and
their
locations
by
evaluating
important
ecological
parameters,
pesticide
use
information,
geographic
relationship
between
specific
pesticide
uses
and
species
locations,
and
biological
requirements
and
behavioral
aspects
of
the
particular
species,
as
part
of
a
refined
species­
specific
analysis.
When
conducted,
this
species­
specific
analysis
will
take
into
consideration
any
regulatory
changes
recommended
in
this
RED
that
are
being
implemented
at
that
time.

Following
this
future
species­
specific
analysis,
a
determination
that
there
is
a
likelihood
of
potential
impact
to
a
listed
species
or
its
critical
habitat
may
result
in:
limitations
on
the
use
of
sodium
chlorate,
other
measures
to
mitigate
any
potential
impact,
or
consultations
with
the
Fish
and
Wildlife
Service
or
the
National
Marine
Fisheries
Service
as
necessary.
If
the
Agency
determines
use
of
sodium
chlorate
"
may
affect"
listed
species
or
their
designated
critical
habitat,
59
EPA
will
employ
the
provisions
in
the
Services
regulations
(
50
CFR
Part
402).
Until
that
species­
specific
analysis
is
completed,
the
risk
mitigation
measures
being
implemented
through
this
RED
will
reduce
the
likelihood
that
endangered
and
threatened
species
may
be
exposed
to
sodium
chlorate
at
levels
of
concern.
EPA
is
not
requiring
specific
sodium
chlorate
label
language
at
the
present
time
relative
to
threatened
and
endangered
species.
If,
in
the
future,
specific
measures
are
necessary
for
the
protection
of
listed
species,
the
Agency
will
implement
them
through
the
Endangered
Species
Protection
Program.

2.
Spray
Drift
Management
The
Agency
has
been
working
closely
with
stakeholders
to
develop
improved
approaches
for
mitigating
risks
to
human
health
and
the
environment
from
pesticide
spray
and
dust
drift.
As
part
of
the
reregistration
process,
EPA
will
continue
to
work
with
all
interested
parties
on
this
important
issue.

From
its
assessment
of
sodium
chlorate,
as
summarized
in
this
document,
the
Agency
concludes
that
certain
drift
mitigation
measures
are
needed
to
address
the
risks
from
off­
target
drift
for
sodium
chlorate,
including
a
requirement
for
medium
to
coarse
droplet
size.
Label
statements
implementing
these
measures
are
listed
in
the
"
spray
drift
management"
section
of
the
label
table
(
Table
28
in
Section
V
of
this
RED
document.
In
the
future,
sodium
chlorate
product
labels
may
need
to
be
revised
to
include
additional
or
different
drift
label
statements.
60
V.
What
Registrants
Need
to
Do
A.
Manufacturing­
Use
Products
1.
Generic
Data
Requirements
The
generic
data
base
supporting
the
reregistration
of
sodium
chlorate
has
been
reviewed
and
determined
to
be
substantially
complete.
However,
there
are
a
few
data
gaps
remaining,
and
these
data,
presented
in
Table
27,
must
be
submitted
or
the
Agency
may
take
regulatory
action
on
registrations
of
pesticide
products
containing
sodium
chlorate.

Table
27.
Guideline
Requirements
for
Sodium
Chlorate
Data
Requirement
Old
Guideline
Number
New
OPPTS
Guideline
No.

Magnitude
of
the
Residue­
Meat/
Milk/
Poultry/
Eggs
171­
4j
860.1480
Submittal
of
Analytical
Reference
Standards
171­
13
860.1650
28­
Day
Inhalation
Toxicity
82­
4
870.3465
Terrestrial
Field
Dissipation
or
Retrospective
Monitoring
Study
164­
1
835.6100
Freshwater
Fish
Early
Life
Stage
72­
4
(
a)
850.1400
Avian
Reproduction
(
1­
Generation,
Duck)
71­
4b
850.2300
Seedling
Emergence
(
Tier
II
only)
123­
1
(
a)
850.4225
Vegetative
Vigor
(
Tier
II
only)
123­
1
(
b)
850.4250
Aquatic
Plant
Toxicity,
using
Lemna
spp.
(
Tier
II)
123­
2
850.4400
Honey
Bee
Acute
Contact
Toxicity
141­
1
850.3020
While
the
terrestrial
field
dissipation
(
835.6100)
guideline
study
may
not
be
appropriate
for
sodium
chlorate,
the
Agency
is
still
concerned
about
the
prolonged
use
of
sodium
chlorate
on
cotton
(
about
50
years).
Terrestrial
field
dissipation
data
are
not
available
for
sodium
chlorate,
and
the
guideline
requirement
for
this
study
was
never
waived.
There
are
some
reports
that
sodium
chlorate
can
be
persistent
in
the
field
(
ranging
from
6
months
to
5
years,
depending
on
application
rate,
soil
type,
fertility,
organic
matter,
moisture,
and
weather
conditions).
Also,
several
labels
report
that
sodium
chlorate
is
effective
for
the
control
of
weeds
for
up
to
a
year,
which
indicates
that
chlorate
may
persist
for
up
to
a
year.
Therefore,
the
range
of
persistence
of
sodium
chlorate
in
the
field
remains
a
major
uncertainty
in
the
environmental
fate
behavior
of
this
chemical.
Use
of
sodium
chlorate
in
the
field
requires
that
it
be
applied
in
conjunction
with
a
fire
retardant
to
minimize
fire
incidents.
It
is
unclear
how
the
fire
retardant
could
influence
the
persistence
in
the
field.
Even
though
the
persistence
of
chlorate
in
the
field
is
uncertain,
a
terrestrial
field
dissipation
data
from
a
study
conducted
as
per
guideline
835.6100
may
not
provide
adequate
data
because
of
the
complexity
of
the
chlorine
oxyanion
system
and
analytical
chemistry
methodology.
Given
that
chloride
is
the
end
chemical
species
of
chlorate,
it
poses
the
61
question
of
increased
chloride
from
year­
after­
year
usage
(
i.
e.,
salinization),
and
leaching
of
chloride
to
ground
water,
particularly
in
areas
where
chloride
is
not
a
significant,
natural
component
in
soil
and/
or
ground
water.
Therefore,
the
Agency
recommends
a
retrospective
monitoring
study
(
soil;
ground
water)
aimed
to
address
the
effect
of
prolong
use
of
sodium
chlorate
on
cotton.
The
study
must
be
conducted
upon
agreement
of
a
protocol,
but
monitoring
sites
in
coastal
areas
should
not
be
included.

2.
Labeling
for
Manufacturing­
Use
Products
To
ensure
compliance
with
FIFRA,
manufacturing­
use
product
(
MUP)
labeling
should
be
revised
to
comply
with
all
current
EPA
regulations,
PR
Notices,
and
applicable
policies.
The
MUP
labeling
should
bear
the
labeling
contained
in
Table
28.

B.
End­
Use
Products
1.
Additional
Product­
Specific
Data
Requirements
Section
4(
g)(
2)(
B)
of
FIFRA
calls
for
the
Agency
to
obtain
any
needed
product­
specific
data
regarding
the
pesticide
after
a
determination
of
eligibility
has
been
made.
The
registrant
must
review
previous
data
submissions
to
ensure
that
they
meet
current
EPA
acceptance
criteria
and
if
not,
commit
to
conduct
new
studies.
If
a
registrant
believes
that
previously
submitted
data
meet
current
testing
standards,
then
the
study
MRID
numbers
should
be
cited
according
to
the
instructions
in
the
Requirement
Status
and
Registrants
Response
Form
provided
for
each
product.
The
Agency
intends
to
issue
a
separate
product­
specific
data
call­
in
(
PDCI)
outlining
specific
data
requirements.

2.
Labeling
for
End­
Use
Products
To
be
eligible
for
reregistration,
labeling
changes
are
necessary
to
implement
measures
outlined
in
Section
IV
above.
Specific
language
to
incorporate
these
changes
is
provided
in
Table
28.
Generally,
conditions
for
the
distribution
and
sale
of
products
bearing
old
labels/
labeling
will
be
established
when
the
label
changes
are
approved.
However,
specific
existing
stocks
time
frames
will
be
established
case­
by­
case,
depending
on
the
number
of
products
involved,
the
number
of
label
changes,
and
other
factors.

C.
Labeling
Changes
Summary
Table
For
sodium
chlorate
to
be
eligible
for
reregistration,
all
sodium
chlorate
labels
must
be
amended
to
incorporate
the
risk
mitigation
measures
outlined
in
Section
IV.
Table
28
describes
how
language
on
the
labels
should
be
amended.

D.
Existing
Stocks
Registrants
may
generally
distribute
and
sell
products
bearing
old
labels/
labeling
for
18
months
after
the
date
of
approval
of
revised
labels
implementing
the
changes
described
in
this
RED.
Registrants
and
all
other
persons
remain
obligated
to
meet
pre­
existing
label
requirements
62
and
existing
stocks
requirements
applicable
to
stocks
they
sell
or
distribute.
