Document ID: EPA-HQ-OPP-2006-0320-0021
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2006-09-22T04:00Z

Page
1
of
23
UNITED
STATES
ENVIRONMENTAL
PROTECTION
AGENCY
WASHINGTON,
D.
C.
20460
OFFICE
OF
PREVENTION,
PESTICIDES
AND
TOXIC
SUBSTANCES
July
27,
2006
Memorandum
SUBJECT:
TCMTB
[
2­(
Thiocyanomethylthio)
benzothiazole]:
Second
Revision
of
the
Occupational
and
Residential
Exposure
Assessment
for
the
Reregistration
Eligibility
Decision
Document.

PC
Code:
035603
(
TCMTB)

DP
Barcode:
D324013
FROM:
Charles
Smith
Reregistration
Branch
2
Health
Effects
Division
(
7509C)

THROUGH:
Alan
Nielsen,
Senior
Scientist
Reregistration
Branch
2
Health
Effects
Division
(
7509C)

TO:
Kathryn
Avivah
Jakob,
Chemical
Review
Manager
Regulatory
Management
Branch
2
Antimicrobials
Division
(
7510C)

and
Deborah
Smegal,
Risk
Assessor
Reregistration
Branch
1
Health
Effects
Division
(
7509C)

The
attached
assessment
is
the
occupational
and
non­
occupational
(
residential)
exposure
and
risk
estimates
for
TCMTB
to
support
the
Antimicrobial
Division's
reregistration
eligibility
Page
2
of
23
decision
(
RED)
document.
The
assessment
was
reviewed
by
HED's
Science
Council
for
Exposure
(
ExpoSAC)
to
ensure
compliance
with
current
HED
policy
as
well
as
ExpoSAC
standard
operating
procedures
(
SOPs)
for
conducting
occupational
and
residential
exposure
(
ORE)
assessments.
Page
3
of
23
Table
of
Contents
Executive
Summary....................................................................................................................
4
1.0
Occupational
and
Residential
Exposure/
Risk
Assessment................................................
5
1.1
Purpose
.......................................................................................................................
5
1.2
Criteria
for
Conducting
Exposure
Assessments............................................................
5
1.3
Summary
of
Hazard
Concerns
for
TCMTB..................................................................
5
1.4
Incident
Reports
..........................................................................................................
8
1.5
Summary
of
Physical
and
Chemical
Properties
of
TCMTB..........................................
8
1.6.1
End­
Use
Products
................................................................................................
9
1.6.2
Registered
Use
Categories
and
Sites
....................................................................
9
1.6.3
Application
Methods............................................................................................
9
2.0
Occupational
Exposures
and
Risks
................................................................................
10
2.1
Occupational
Handler
Exposures
and
Risks
...............................................................
10
2.1.1
Data
and
Assumptions
for
Handler
Exposure
Scenarios
.....................................
12
2.1.1.1
Assumptions
for
Handler
Exposure
Scenarios
................................................
12
2.1.1.2
Exposure
Data
for
Handler
Exposure
Scenarios
.............................................
13
2.1.2
Noncancer
TCMTB
Handler
Exposure
and
Assessment
.....................................
16
2.1.2.1
Noncancer
TCMTB
Handler
Exposure
and
Risk
Calculations........................
16
2.1.2.2
TCMTB
Noncancer
Risk
Summary................................................................
17
2.1.3
Cancer
TCMTB
Handler
Exposure
and
Risk
Assessment...................................
22
2.1.4
Summary
of
Risk
Concerns/
Data
Gaps
for
Occupational
Handlers.....................
22
2.1.4.1
Summary
of
Risk
Concerns............................................................................
22
2.1.4.2
Summary
of
Data
Gaps
..................................................................................
22
2.1.5
Recommendations
For
Refining
Handler
Risk
Assessment
...............................
22
Page
4
of
23
Executive
Summary
TCMTB
is
a
broad
spectrum
biocide
used
in
commercial
and
on­
farm
seed
treatment
settings.
It
is
formulated
as
a
liquid
concentrate.

Hazard
Concerns:
The
toxicological
endpoints
used
to
complete
the
occupational
and
residential
risk
assessment
were
based
on
the
best
professional
judgment
of
AD
toxicologists.
Adverse
effects
were
identified
at
durations
of
exposure
ranging
from
short­
term
(
up
to
30
days)
to
intermediate­
term
durations
(>
30
days
up
to
6
months)
and
long­
term
durations
(>
6
months).
No
cancer
endpoint
was
identified,
therefore,
cancer
risks
are
not
assessed.

The
short­
and
intermediate­
term
(
noncancer)
dermal
risk
assessment
for
TCMTB
is
based
on
an
NOAEL
of
25
mg/
kg/
day
from
a
dermal
study.
The
NOAEL
was
based
on
decreased
body
weight
gain
and
food
consumption
in
males,
in
addition
to
significant
hematalogical
(
increased
neutrophils,
decreased
hemoglobin,
hematocrit
and
erythrocytes)
and
clinical
chemistry
changes
(
increased
urea
nitrogen,
glucose
and
globulins).
Long­
term
exposures
to
TCMTB
(
i.
e.,
greater
than
6
months)
are
not
expected
for
current
registered
uses.
HED's
level
of
concern
(
LOC)
for
occupational
TCMTB
dermal
exposures
is
100.
The
shortand
intermediate­
term
(
noncancer)
inhalation
risk
assessment
for
TCMTB
is
based
on
an
NOAEL
of
16
mg/
kg/
day,
which
is
based
on
an
oral
rabbit
development
study.
The
NOAEL
was
based
on
reduced
body
weight
gain
and
food
consumption.
Long­
term
exposure
to
TCMTB
(
i.
e.,
greater
than
6
months)
is
not
expected
for
current
registered
uses.
HED's
level
of
concern
(
LOC)
for
short­
and
intermediate­
term
occupational
(
and
residential)
TCMTB
inhalation
exposures
is
100.
The
dermal
and
inhalation
margins
of
exposure
were
combined
for
the
TCMTB
risk
assessment
because
the
toxicity
endpoints
for
the
dermal
and
inhalation
routes
of
exposure
are
based
on
the
same
toxicological
effects.

The
Health
Effects
Division
Carcinogenicity
Peer
Review
Committee
(
CPRC)
met
on
June
28,
1995
to
discuss
and
evaluate
the
weight­
of­
the­
evidence
on
2­(
Thiocyanomethylthio)
benzothiazole
(
TCMTB)
with
particular
reference
to
its
carcinogenic
potential.
The
CPRC
concluded
that
TCMTB
should
be
classified
as
Group
C
­
possible
human
carcinogen
­
and
recommended
that
for
the
purpose
of
risk
characterization,
the
Reference
Dose
(
RfD)
approach
should
be
used
for
quantitation
of
human
risk.
This
was
based
on
statistically
significant
increases
in
tumors
in
both
sexes
of
the
Sprague­
Dawley
rat:
testicular
interstitial
cell
adenomas
in
males
and
thyroid
c­
cell
adenomas
in
females.

Use
Patterns:
TCMTB
is
a
fungicide
used
for
treating
seeds
in
the
United
States.
It
is
used
in
commercial
and
on­
farm
settings.

Occupational
Handler
Risks:
For
commercial
and
on­
farm
seed
treatment
scenarios,
all
dermal
and
inhalation
MOEs
met
or
exceeded
the
required
uncertainty
factor
of
100
at
some
level
of
mitigation.
For
commercial
and
on­
farm
seed
treatment
scenarios,
all
combined
dermal
and
inhalation
risks
met
or
exceed
the
required
uncertainty
factor
of
100
at
some
level
of
mitigation.
Page
5
of
23
1.0
Occupational
and
Residential
Exposure/
Risk
Assessment
1.1
Purpose
This
document
is
the
occupational
and
residential
non­
dietary
exposure
and
risk
assessment
for
TCMTB
from
its
use
as
a
fungicide.
In
this
document,
which
is
for
use
in
EPA's
development
of
the
Antimicrobials
Division
(
AD)
chapter
of
the
TCMTB
RED
Document,
EPA
presents
the
results
of
its
review
of
the
potential
human
health
effects
of
occupational
and
residential/
non­
occupational
exposure
to
TCMTB.

1.2
Criteria
for
Conducting
Exposure
Assessments
An
occupational
and/
or
residential
exposure
assessment
is
required
for
an
active
ingredient
if
(
1)
certain
toxicological
criteria
are
triggered
and
(
2)
there
is
a
potential
for
exposure
to
handlers
(
mixers,
loaders,
applicators)
during
use
or
to
persons
entering
treated
sites
or
exposed
to
vapors
after
application
is
complete.
Toxicological
endpoints
were
selected
for
short­
and
intermediate­
term
dermal
and
inhalation
exposures
to
TCMTB.
There
is
a
significant
potential
for
exposure
in
a
variety
of
occupational
agricultural
and
commercial
seed
treatment
settings.
There
are
no
residential
uses
currently
registered
for
TCMTB.
Therefore,
risk
assessments
are
required
for
occupational
handlers
that
can
occur
as
a
result
of
TCMTB
use.

1.3
Summary
of
Hazard
Concerns
for
TCMTB
2­(
Thiocyanomethylthio)
benzothiazole
(
TCMTB)
­
Report
of
the
Antimicrobials
Division
Toxicity
Endpoint
Selection
Committee
(
ADTC).
M.
McMahon
and
M.
Centra
dated
January
12,
2006.

The
toxicological
endpoints
used
to
complete
the
occupational
and
residential
risk
assessment
were
based
on
the
best
professional
judgment
of
AD
toxicologists.
Adverse
effects
were
identified
at
durations
of
exposure
ranging
from
short­
term
(
up
to
30
days)
to
intermediateterm
durations
(>
30
days
up
to
6
months)
and
long­
term
durations
(>
6
months).
No
cancer
endpoint
was
identified,
therefore,
cancer
risks
are
not
assessed.

TCMTB
is
a
fungicide
where
the
use
patterns
can
vary
widely
ranging
from
short­
term
through
intermediate­
term
exposure
durations.
As
such,
when
the
Antimicrobials
Division
Toxicity
Endpoint
Selection
Committee
(
ADTC)
evaluated
the
TCMTB
hazard
database,
endpoints
were
selected
to
address
the
various
durations
of
exposure.
TCMTB
exposures
are
expected
to
occur
only
to
occupational
users.
Page
6
of
23
Dermal
Route
(
noncancer)

The
short­
and
intermediate­
term
(
noncancer)
dermal
risk
assessment
for
TCMTB
is
based
on
an
NOAEL
of
25
mg/
kg/
day
from
a
dermal
study.
The
NOAEL
was
based
on
decreased
body
weight
gain
and
food
consumption
in
males,
in
addition
to
significant
hematalogical
(
increased
neutrophils,
decreased
hemoglobin,
hematocrit
and
erythrocytes)
and
clinical
chemistry
changes
(
increased
urea
nitrogen,
glucose
and
globulins).
Long­
term
exposures
to
TCMTB
(
i.
e.,
greater
than
6
months)
are
not
expected
for
current
registered
uses.

Inhalation
Route
(
noncancer)

The
short­
and
intermediate­
term
(
noncancer)
inhalation
risk
assessment
for
TCMTB
is
based
on
an
NOAEL
of
16
mg/
kg/
day,
which
is
based
on
an
oral
rabbit
development
study.
The
LOAEL
was
based
on
reduced
body
weight
gain
and
food
consumption.
Long­
term
exposure
to
TCMTB
(
i.
e.,
greater
than
6
months)
is
not
expected
for
current
registered
uses.

Incidental
Oral
Route
(
noncancer)

The
short­
and
intermediate­
term
(
noncancer)
incidental
oral
risk
assessment
for
TCMTB
is
based
on
an
NOAEL
of
16
mg/
kg/
day,
which
is
based
on
an
oral
rabbit
development
study.
The
LOAEL
was
based
on
reduced
body
weight
gain
and
food
consumption.

Noncancer
Level
of
Concern
(
LOC)

HED's
level
of
concern
(
LOC)
for
occupational
TCMTB
dermal
and
inhalation
exposures
is
100
(
i.
e.,
a
margin
of
exposure
(
MOE)
less
than
100
exceeds
HED's
level
of
concern).
The
level
of
concern
is
based
on
a
10x
for
interspecies
extrapolation
and
a
10x
for
intraspecies
extrapolation.

Aggregation
The
dermal
and
inhalation
margins
of
exposure
were
combined
for
the
TCMTB
risk
assessment
because
the
toxicity
endpoints
for
the
dermal
and
inhalation
routes
of
exposure
are
based
on
the
same
toxicological
effects.

Cancer
The
Health
Effects
Division
Carcinogenicity
Peer
Review
Committee
(
CPRC)
met
on
June
28,
1995
to
discuss
and
evaluate
the
weight­
of­
the­
evidence
on
2­(
Thiocyanomethylthio)
benzothiazole
(
TCMTB)
with
particular
reference
to
its
carcinogenic
potential.
The
CPRC
concluded
that
TCMTB
should
be
classified
as
Group
C
­
possible
human
carcinogen
­
and
recommended
that
for
the
purpose
of
risk
characterization,
the
Reference
Dose
(
RfD)
approach
should
be
used
for
quantitation
of
human
risk.
This
was
based
on
statistically
significant
increases
in
tumors
in
both
sexes
of
the
Sprague­
Dawley
rat:
testicular
interstitial
cell
adenomas
in
males
and
thyroid
C­
cell
adenomas
in
females.
Page
7
of
23
Acute
Toxicity
TCMTB
is
classified
as
category
II
for
acute
oral
toxicity,
category
III
for
acute
dermal
toxicity,
and
category
I
for
inhalation
toxicity.
It
is
classified
as
category
I
for
primary
eye
irritation
potential
and
category
II
for
primary
skin
irritation
potential.
Results
were
positive
for
dermal
sensitization.
The
acute
toxicity
profile
for
TCMTB
is
presented
in
Table
1.

Body
Weight
The
adverse
effects
for
the
dermal
and
inhalation
endpoint
are
observed
in
the
general
population.
Therefore,
the
body
weight
of
an
average
adult
(
i.
e.,
70
kg)
was
used
to
estimate
dermal
dose.

Table
1.
Acute
Toxicity
Profile
­
TCMTB
Guideline
No.
Study
Type
MRID(
s)
Results
Toxicity
Category
81­
1
Acute
Oral
41583801
LD50
=
750
mg/
kg
II
81­
2
Acute
Dermal
41515401
LD50
>
2000
mg/
kg
III
81­
3
Acute
Inhalation
41640601
LC50
=
0.07
mg/
L
I
81­
4
Primary
Eye
Irritation
Acc
no.
111991
I
81­
5
Primary
Skin
Irritation
41583701
Severe
erythema
at
72
hrs.
II
81­
6
Dermal
Sensitization
42349201
Sensitizer
Table
2.
Summary
of
Toxicological
Doses
and
Endpoints
for
TCMTB
Exposure
Scenario
Dose
Used
in
Risk
Assessment,
UF
Special
FQPA
SF*
and
Level
of
Concern
for
Risk
Assessment
Study
and
Toxicological
Effects
Acute
Dietary
(
general
population)
NOAEL
=
25.1
mg/
kg/
day
UF
=
100
Acute
RfD
=
0.25
mg/
kg/
day
FQPA
SF
=
1X
aPAD
=
acute
RfD
FQPA
SF
aPAD
=
0.25
mg/
kg/
day
Rat
Developmental
Study
LOAEL
=
76.5
mg/
kg/
day
based
on
clinical
signs
of
ventral
toxicity
(
alopecia,
rough
coat,
dyspnea/
wheezing,
oral
discharge,
diarrhea/
loose
stool,
urine
staining,
piloerection
and
hunched
gait).

Chronic
Dietary
(
all
populations)
LOAEL
=
3.8
mg/
kg/
day
UF
=
300
Chronic
RfD
=
0.013
mg/
kg/
day
FQPA
SF
=
1X
PAD
=
chronic
RfD
FQPA
SF
cPAD
=
0.013
mg/
kg/
day
One­
year
Dog
Study
LOAEL
=
3.8
mg/
kg/
day
based
on
decreased
body
weight
gain,
white
cells,
monocytes
and
plasma
ALT
in
males
and
decreased
plasma
ALT
and
uterine
weight
in
females.
Page
8
of
23
Table
2.
Summary
of
Toxicological
Doses
and
Endpoints
for
TCMTB
Exposure
Scenario
Dose
Used
in
Risk
Assessment,
UF
Special
FQPA
SF*
and
Level
of
Concern
for
Risk
Assessment
Study
and
Toxicological
Effects
Incidental
Oral
Shortand
Intermediate­
Term
(
1
­
30
days)
NOAEL
=
16
mg/
kg/
day
UF
=
100
MOE
=
100
Rabbit
Developmental
Study
LOAEL
=
32
mg/
kg/
day
based
on
reduced
body
weight
gain
and
food
consumption.

Dermal
Short­,
Intermediate­,
and
Long­
Term
(
1
­
30
days)
Dermal
NOAEL
=
25
mg/
kg/
day
MOE
=
100
21­
Day
Dermal
toxicity
study
in
Rats
LOAEL
=
100
mg/
kg/
day
for
systemic
toxicity
based
on
decreased
body
weight
gain
and
food
consumption
in
males,
in
addition
to
significant
hematalogical
(
increased
neutrophils,
decreased
hemoglobin,
hematocrit
and
erythrocytes)
and
clinical
chemistry
changes
(
increased
urea
nitrogen,
glucose
and
globulins).

Inhalation
Short­
and
Intermediate­
Term
(
1
­
30
days)
NOAEL
=
16
mg/
kg/
day
(
Inhalation
absorption
rate
=
100%)
MOE
=
100
Rabbit
Developmental
Study
LOAEL
=
32
mg/
kg/
day
based
on
reduced
body
weight
gain
and
food
consumption.

Inhalation
Long­
Term
(>
6
months)
LOAEL
=
3.8
mg/
kg/
day
(
Inhalation
absorption
rate
=
100%)
MOE
=
1000
One­
year
Dog
Study
LOAEL
=
3.8
mg/
kg/
day
based
on
decreased
body
weight
gain,
white
cells,
monocytes
and
plasma
ALT
in
males
and
decreased
plasma
ALT
and
uterine
weight
in
females.

1.4
Incident
Reports
An
analysis
of
incidence
reports
will
be
included
in
a
separate
memo.

1.5
Summary
of
Physical
and
Chemical
Properties
of
TCMTB
TCMTB
(
CAS
registry
number
21564­
17­
0)
is
a
dark
orange
liquid
with
a
molecular
formula
of
C9H6N2S3
and
a
molecular
weight
of
238.3
g/
mole.
It
is
has
a
faint,
mild
odor.
TCMTB
is
miscible
with
most
organic
solvents
and
can
be
formulated
with
a
range
of
surface
active
agents
which
can
form
stable
emulsions
when
diluted
further
with
water.
Page
9
of
23
1.6
Summary
of
Use
Patterns
and
Formulations
1.6.1
End­
Use
Products
TCMTB
is
a
fungicide
used
for
treating
seeds
in
the
United
States.
It
is
used
in
agricultural
and
commercial
settings.
TCMTB
is
formulated
as
a
liquid.

1.6.2
Registered
Use
Categories
and
Sites
An
analysis
of
the
current
labeling
and
available
use
information
was
completed
by
HED.
TCMTB
is
registered
for
use
in
agricultural
and
commercial
seed
treating
(
see
Table
3).

Table
3:
Summary
of
Maximum
Application
Rates
for
Registered
TCMTB
Commercial
and
Agricultural
Uses
Crop
Target
Formulationa
Maximum
Application
Rate
Application
Equipment
(
Area
Treated
or
Amount
Handled
Daily)

Barley
Seed,
Oat
Seed,
Rice
Seed,
Wheat
Seed
Seed
L
0.026
lbs
ai/
100
lbs
of
seed
commercial
treater
0.13
lbs
ai/
100
lbs
of
seed
commercial
treater
Cotton
Seed
Seed
L
0.051
lbs
ai/
100
lbs
of
seed
on­
farm
treater
Safflower
Seed,
Sugar
beet
Seed
Seed
L
0.041
lbs
ai/
100
lbs
of
seed
commercial
treater
a
L
=
Liquid
concentrate
1.6.3
Application
Methods
TCMTB
is
applied
to
seeds
during
both
on­
farm
and
commercial
seed
treatment.
The
following
descriptions
of
seed
treatment
and
planting
methods
and
equipment
are
based
primarily
on
information
provided
in
HED's
seed
treatment
SOP
(
SOP
14),
which
was
developed
in
consultation
with
industry
specialists.

Commercial
Seed
Treatment:
Commercial
seed
treaters
are
designed
to
apply
accurately
measured
quantities
of
pesticides
to
a
given
weight
of
seed.
There
are
two
primary
methods
for
treating
seeds:
the
batch
system
and
the
continuous
flow
system.
The
batch
system
is
less
automated
and
generates
lower
production
volume
than
the
continuous
flow
system.
Seed
treatment
in
commercial
facilities
occurs
primarily
via
the
highly
automated
continuous
flow
system.
Treated
seed
is
bagged
by
a
machine
which
picks
up
a
bag,
opens
it,
and
lets
it
fill
to
a
predetermined
weight.
The
bagger
then
folds
the
top
of
the
bag,
and
attaches
the
seed
grade
certificates
and
treatment
tags.
The
sewer
then
sews
the
bag
shut
using
an
automated
sewing
machine.
The
bag
is
then
moved
by
a
conveyer
belt
to
a
pallet
area
where
it
is
stacked
for
Page
10
of
23
shipping.
Seed
treatment
workers
may
rotate
duties
to
other
areas.
In
the
smaller,
less
automated
facilities
in
particular,
one
worker
will
often
have
multiple
duties
within
the
plant.

On­
farm
Seed
Treatment
&
Planting
of
Treated
Seed:
There
are
various
pieces
of
equipment
used
for
on­
farm
seed
treatment,
such
as
drum
mixers,
homemade
devices
using
augers,
cement
mixers,
hand
cranked
revolving
drums,
and
gravity
feed
systems.
The
more
sophisticated
on­
farm
treaters
are
essentially
miniature
versions
of
the
commercial
treaters.
Simpler
units
consist
of
reusable
chemical
containers,
a
power
source
(
vehicle
battery),
valve
and
pump
or
compressed
air,
and
tubing
spray
nozzles.
These
units
are
mounted
directly
on
a
truck
box
or
wagon
to
dispense
seed
treatment
directly
into
an
auger
conveyance
system.
Seed
may
be
treated
as
it
is
augered
from
the
grower's
truck
to
the
storage
bin
or
seeder
or
from
the
storage
bin
to
the
farmer's
truck
or
seeder.
This
type
of
enclosed
on­
farm
treatment
system
is
available
only
for
liquid
formulations.

The
treated
seed
can
be
planted
with
a
wide
range
of
equipment.
Common
equipment
types
include:
specialized
drills
with
a
box
for
small
seeds
and
disk
openers
with
depth
bands
to
place
the
seeds
at
the
appropriate
depth
followed
by
packer
wheels
to
firm
soil
over
and
around
seeds;
double
corrugated
roller
seeders,
which
drop
the
seed
between
the
rollers
followed
by
a
second
roller,
which
covers
the
seed
and
firms
the
soil;
and
booms,
delivery
tubes,
and
air
pressure
that
blow
seed
onto
the
soil
at
properly
spaced
intervals
followed
by
light
packing,
dragging
a
chain
or
harrowing
to
cover
the
planted
seed.
Seeding
rate
is
determined
by
factors
such
as
machine
wear,
seed
size
and
shape,
and
crop
variety.

2.0
Occupational
Exposures
and
Risks
There
is
a
potential
for
exposure
to
TCMTB
in
occupational
scenarios
from
handling
TCMTB
products
during
the
seed
treating
process
(
both
commercial
and
on­
farm)
and
a
potential
for
postapplication
worker
exposure
from
handling
seed
previously
treated
with
TCMTB.
As
a
result,
risk
assessments
have
been
completed
for
occupational
handler
scenarios
as
well
as
occupational
postapplication
scenarios.

2.1
Occupational
Handler
Exposures
and
Risks
HED
uses
the
term
"
handlers"
to
describe
those
individuals
who
are
involved
in
the
pesticide
application
process.
HED
believes
that
there
are
distinct
job
functions
or
tasks
related
to
applications
and
that
exposures
can
vary
depending
on
the
specifics
of
each
task.
Job
requirements
(
e.
g.,
amount
of
chemical
to
be
used
in
an
application),
the
kinds
of
equipment
used,
the
target
being
treated,
and
the
level
of
protection
used
by
a
handler
can
cause
exposure
levels
to
differ
in
a
manner
specific
to
each
application
event.

HED
uses
exposure
scenarios
to
describe
the
various
types
of
handler
exposures
that
may
occur
for
a
specific
active
ingredient.
The
use
of
scenarios
as
a
basis
for
exposure
assessment
is
Page
11
of
23
very
common
as
described
in
the
U.
S.
EPA
Guidelines
for
Exposure
Assessment
(
U.
S.
EPA;
Federal
Register
Volume
57,
Number
104;
May
29,
1992).
Information
from
the
current
labels,
use
and
usage
information,
toxicology
data,
and
exposure
data
were
all
key
components
in
the
development
of
the
exposure
scenarios.
HED
has
developed
a
series
of
general
descriptions
for
tasks
that
are
associated
with
pesticide
applications.
Tasks
associated
with
occupational
pesticide
handlers
are
categorized
using
one
of
the
following
terms:

On­
farm
Loader/
Applicator:
The
possible
points
of
operator
exposure
for
an
on­
farm
treatment
are;
transport
of
pesticide
in
mobile
containers,
moving
pesticide
from
storage
in
to
seed
treatment
equipment,
introduction
of
pesticide
into
seed
treatment
equipment,
and
equipment
cleaning
and
maintenance.
On­
farm
seed
treatment
with
liquid
formulations
is
generally
done
with
more
automated
equipment,
essentially
miniature
versions
of
commercial
treaters.
Seed
may
be
treated
as
it
is
augured
from
the
grower's
truck
to
the
storage
bin
(
at
the
farmstead),
or
from
the
truck
to
the
seeder
(
field)
or
from
the
grower's
storage
bin
into
either
a
truck
or
seeder.

 
On­
farm
Planting
of
Treated
Seed:
Planting
exposures
occur
during
both
the
loading
of
hoppers
and
driving
the
equipment.

 
Commercial
Mixer/
Loader/
Applicator
for
Seed
Treatments:
This
scenario
involves
loading/
applying
of
all
formulations
in
a
commercial
operation.

 
Commercial
Bagger
for
Seed
Treatments:
Seed
is
bagged
by
a
machine
which
picks
up
a
bag,
opens
it,
slips
it
over
a
spout
and
lets
it
fill
to
a
predetermined
weight.
The
bagger
then
folds
the
top
of
the
bag,
attaches
the
seed
grade
certificates
and
treatment
tags.

 
Commercial
Sewer
for
Seed
Treatments:
After
bagging
the
treated
seed
the
sewer
shuts
the
bag
using
an
automatic
sewing
machine.
The
bag
is
then
moved
by
a
conveyer
belt
to
a
pallet
area
where
it
is
stacked
for
shipping.

 
Multiple
Commercial
Activities
for
Seed
Treatments:
The
SOP
contains
a
scenario
labeled
"
Multiple
Activities"
to
address
the
potential
for
multiple
types
of
exposure
in
small
commercial
operations.

A
chemical
can
produce
different
effects
based
on
how
long
a
person
is
exposed,
how
frequently
exposures
occur,
and
the
level
of
exposure.
HED
classifies
exposures
up
to
30
days
as
short­
term
and
exposures
greater
than
30
days
up
to
several
months
as
intermediate­
term.
HED
completes
both
short­
and
intermediate­
term
assessments
for
occupational
scenarios
in
essentially
all
cases,
because
these
kinds
of
exposures
are
likely
and
acceptable
use/
usage
data
are
not
available
to
justify
deleting
intermediate­
term
scenarios.
Based
on
use
data
and
label
instructions,
HED
believes
that
occupational
TCMTB
exposures
may
occur
over
a
single
day
or
up
to
weeks
at
a
time
for
many
use­
patterns
and
that
intermittent
exposure
over
several
weeks
also
may
occur.
Some
applicators
may
apply
TCMTB
over
a
period
of
weeks,
because
they
are
commercial
seed
treaters.
Long­
term
handler
exposures
are
not
expected
to
occur
for
TCMTB.
Page
12
of
23
Other
parameters
are
also
defined
from
use
and
usage
data
such
as
application
rates
and
application
frequency.
HED
always
completes
noncancer
risk
assessments
using
maximum
application
rates
for
each
in
order
to
ensure
there
are
no
concerns
for
each
specific
use.

Occupational
handler
exposure
assessments
are
completed
by
HED
using
different
levels
of
risk
mitigation.
Typically,
HED
uses
a
tiered
approach.
The
lowest
tier
is
designated
as
the
baseline
exposure
scenario
(
i.
e.,
long­
sleeve
shirt,
long
pants,
shoes,
socks,
and
no
respirator).
If
risks
are
of
concern
at
baseline
attire,
then
increasing
levels
of
personal
protective
equipment
or
PPE
(
e.
g.,
gloves,
double­
layer
body
protection,
and
respirators)
are
evaluated.
If
risks
remain
a
concern
with
maximum
PPE,
then
engineering
controls
(
e.
g.,
closed
mixing/
loading
systems)
are
evaluated.
This
approach
is
used
to
ensure
that
the
lowest
level
of
risk
mitigation
that
provides
adequate
protection
is
selected,
since
the
addition
of
PPE
and
engineering
controls
involves
an
additional
expense
to
the
user
and
 
in
the
case
of
PPE
 
also
involves
an
additional
burden
to
the
user
due
to
decreased
comfort
and
dexterity
and
increased
heat
stress
and
respiratory
stress.

2.1.1
Data
and
Assumptions
for
Handler
Exposure
Scenarios
2.1.1.1
Assumptions
for
Handler
Exposure
Scenarios
A
series
of
assumptions
and
exposure
factors
served
as
the
basis
for
completing
the
occupational
handler
risk
assessments.
Each
assumption
and
factor
is
detailed
below
on
an
individual
basis.
The
assumptions
and
factors
used
in
the
risk
calculations
include:

 
Occupational
handler
exposure
estimates
were
based
on
surrogate
data
from:
the
Health
Effects
Division
Science
Advisory
Committee
on
Exposure
(
HED
ExpoSAC)
SOP
#
15:
Amount
of
Seed
Treated
or
Planted
per
Day,
which
was
completed
on
March
2,
2004.

 
The
toxicological
endpoint
of
concern
for
dermal
risks
is
from
a
dermal
study;
with
the
effects
seen
in
males
and
females,
therefore,
the
average
body
weight
of
an
adult
handler
(
i.
e.,
70
kg)
is
used
to
complete
the
dermal
noncancer
risk
assessment.
The
toxicological
endpoint
of
concern
for
inhalation
risks
is
from
an
oral
study;
with
the
effects
seen
in
males
and
females,
therefore,
the
average
body
weight
of
an
adult
handler
(
i.
e.,
70
kg)
is
used
to
complete
the
inhalation
noncancer
risk
assessment.

 
Generic
protection
factors
(
PFs)
were
used
to
calculate
exposures
when
data
were
not
available.
For
example,
an
80
percent
protection
factor
was
assumed
for
the
use
of
a
respirator
equipped
with
a
quarter­
face
dust/
mist
filter.

 
On­
farm
treaters
and
planters
are
expected
to
have
short­
term
exposure
duration
(
less
than
30
days)
for
all
seed
crops.

 
Personal
protective
equipment
for
on­
farm
and
commercial
mixer/
loader/
applicators
and
Page
13
of
23
planter
includes
a
single
layer
and
gloves.
Personal
protective
equipment
for
commercial
baggers
and
sewers
includes
baseline
attire
only
­
no
gloves.
Personal
protective
equipment
for
performing
multiple
activities
in
a
commercial
operation
includes
a
single
layer
of
clothing
and
gloves
 
Exposure
factors
used
to
calculate
daily
exposures
to
handlers
are
based
on
applicable
data,
if
available.
For
lack
of
appropriate
data,
values
from
a
scenario
deemed
similar
enough
by
the
assessor
might
be
used.

 
For
noncancer
assessments,
HED
assumes
the
maximum
application
rates
allowed
by
labels
in
its
risk
assessments
(
see
Table
3).

 
The
average
occupational
workday
is
assumed
to
be
8
hours.

 
The
daily
pounds
of
seed
treated
per
day
were
defined
for
each
handler
scenario
by
determining
the
amount
that
can
be
reasonably
treated
in
a
single
day.
These
assumptions
are
taken
from
the
HED's
ExpoSAC
SOP
#
15.
The
standard
values
in
this
SOP
are
based
on
the
information
obtained
from
the
registrants,
seed
treatment
equipment
manufacturers,
and
Agency
experts.
The
values
listed
are
considered
to
be
typical­
tohigh
end
values.
The
default
values
may
be
modified
by
pesticide­
specific
knowledge
that
affects
the
amount
of
seed
that
can
be
treated
or
planted
in
a
day
(
e.
g.,
high
amount
of
seed
required
per
acre)
but
in
the
case
of
TCMTB,
no
such
data
is
available.
The
values
are
as
follows:
­
for
commercial
seed
treatment
facilities
it
is
assumed
that
for
barley,
rice,
safflower,
and
wheat
seed
 
718,000
lb
seed
is
treated
per
day;
for
cotton
seed
 
160,000
lb
seed
is
treated
per
day;
and
for
sugar
beet
seed
 
88,000
lb
seed
is
treated
per
day.
­
for
on
farm
treatments
it
is
assumed
that
200
acres
is
planted
per
day
for
cotton
(
18
lbs
of
seed
per
acre),
oats
(
128
lbs
of
seed
per
acre),
rice
(
150
lbs
of
seed
per
acre),
and
wheat
(
150
lbs
of
seed
per
acre)
seeds;
80
acres
is
planted
per
day
for
safflower
(
100
lbs
of
seed
per
acre)
and
sugar
beet
(
8
lbs
of
seed
per
acre)
seeds;
and
35
acres
is
planted
per
day
for
barley
(
100
lbs
of
seed
per
acre)
seeds.

There
are
data
gaps
that
have
been
identified
for
some
TCMTB
applications.
Each
is
identified
in
the
calculation
tables
and
is
also
noted
in
the
summary
of
risk
calculations.

2.1.1.2
Exposure
Data
for
Handler
Exposure
Scenarios
HED
uses
unit
exposure
to
assess
handler
exposures
to
pesticides.
Unit
exposures
are
estimates
of
the
amount
of
exposure
to
an
active
ingredient
a
handler
receives
while
performing
various
handler
tasks
and
are
expressed
in
terms
of
micrograms
or
milligrams
of
active
ingredient
per
pounds
of
active
ingredient
handled.
HED
has
developed
a
series
of
unit
exposures
that
are
unique
for
each
scenario
typically
considered
in
our
assessments
(
i.
e.,
there
are
different
unit
exposures
for
different
types
of
application
equipment,
job
functions,
and
levels
Page
14
of
23
of
protection).
The
unit
exposure
concept
has
been
established
in
the
scientific
literature
and
also
through
various
exposure
monitoring
guidelines
published
by
the
U.
S.
EPA
and
international
organizations
such
as
Health
Canada
and
OECD
(
Organization
for
Economic
Cooperation
and
Development).

Exposure
data
used
for
the
TCMTB
seed
treatment
assessment
are
taken
primarily
from
HED's
recently
developed
seed
treatment
standard
operating
procedure
(
SOPs
for
Seed
Treatment,
6/
1/
03)
and
also
are
based
on
professional
judgment.
The
seed
treatment
SOP
contains
representative
scenarios
for
worker
exposure
associated
with
seed
treatment
facilities
and
planting
treated
seed.
The
data
contained
in
the
SOP
are
mostly
generated
by
industry
sources.
Exposure
estimates
are
from
actual
seed
treatment
studies
and
are
based
on
exposure
factors
associated
with
occupational
handler
scenarios
(
i.
e.,
commercial
seed
treatment,
on­
farm
seed
treatment,
planting
of
treated
seed).
Eight
seed
treatment
studies
were
used
in
developing
the
SOP.
Given
the
high
level
of
variance
in
the
data,
multiple
statistical
analyses
were
undertaken
to
help
ensure
derivation
of
a
statistically
sound
exposure
value
for
the
different
scenarios
evaluated.
For
all
selected
seed
treatment
studies,
replicates
were
combined
into
sets
of
equivalent
job
functions.
This
process
resulted
in
four
categories
of
commercial
seed
treatment
activities
(
loader/
applicator,
sewer,
bagger,
and
multiple
activities),
and
two
categories
for
on­
farm
activities
(
treater
and
planter).

On­
farm
Seed
Treatment
and
Planting
On­
farm
Loader/
Applicator:
No
studies
were
available
to
address
exposure
to
liquid
formulations
in
an
on­
farm
facility.
On­
farm
seed
treatment
with
liquid
formulations
is
generally
done
with
more
automated
equipment,
essentially
miniature
versions
of
commercial
treaters.

On­
farm
Planting
of
Treated
Seed:
Exposure
estimates
for
loading
and
planting
of
treated
seed
are
based
on
2
exposure
studies
(
MRID
#
42251901,
45654503).
In
one
study,
workers
loaded
and
drilled
seed
treated
with
Baytan
at
13
different
sites
in
the
UK.
The
seed
was
loaded
into
the
drill
hoppers
from
0.5
or
1
ton
super
sacks
or
50
kg
bags.
The
amount
of
seed
handled
ranged
from
1100
to
12,100
lbs
and
the
amount
of
ai
handled
ranged
from
0.35
to
4.72
lbs.
The
loading
time
ranged
from
19
to
83
minutes,
while
the
planting
time
ranged
from
155
to
487
minutes.
The
seed
planting
rate
per
acre
was
not
given.
The
same
worker
performed
both
the
loading
and
planting.
Dermal
exposure
was
measured
with
inner
and
outer
whole
body
dosimeters
which
included
a
cap,
a
jacket
and
trousers
over
a
long
sleeve
T­
shirt
and
long
johns
and
two
sets
of
cotton
gloves.
The
gloves
were
changed
at
the
end
of
loading.
Inhalation
exposures
were
measured
with
37
mm
glass
fiber
filters
and
the
filters
were
changed
after
loading.
The
dermal
results
were
adjusted
by
a
clothing
protection
factor
to
account
for
the
fact
that
5%
of
the
outer
residues
were
found
on
the
inner
dosimeters.

In
the
second
study
workers
loaded
and
drilled
canola
seed
treated
with
Oftanol,
which
forms
a
hard
shell
coating.
The
13
replicates
for
this
study
were
located
at
one
site
in
Manitoba
using
four
different
planting
rigs.
Four
workers
participated
in
the
study
and
the
replicates
averaged
3.2
hours
in
duration.
The
seed
was
loaded
into
the
drill
hoppers
from
25
kg
bags.
The
amount
of
seed
handled
per
replicate
averaged
360
pounds
and
the
amount
of
ai
handled
Page
15
of
23
averaged
4.33
lbs.
The
seed
was
planted
at
a
rate
of
6
to
8
pounds
per
acre.
The
same
worker
performed
both
the
loading
and
planting.
Dermal
exposure
was
measured
with
patches
located
both
inside
and
outside
the
worker's
coverall.
Hand
exposures
were
measured
by
hand
rinse.
Inhalation
exposures
were
measured
with
37
mm
quartz
microfiber
filters.

Commercial
Seed
Treatment
Commercial
Loader/
Applicator:
Exposure
estimates
are
based
on
a
subset
of
3
exposure
studies
(
MRID
Nos.
43080049,
42251902,
44904526).
The
loader/
applicator
activities
in
these
3
exposure
studies
encompass
a
wide
range
of
seed
treaters,
amounts
of
seed
and
amounts
of
pesticides
handled
for
seed
treatment
scenarios.
The
three
studies
monitored
an
open
loading/
applying
activity
for
various
seed
treatment
facilities.
There
is
an
average
of
9
replicates
per
study
(
ranging
from
1
to
20
replicates
per
study).
Two
of
the
three
studies
monitored
dermal
exposures
with
patch
dosimetry,
hand
rinses,
and
face
wipes.
The
methodology
in
the
third
study
was
whole
body
dosimetry,
hand
rinses
and
face
wipes.

Commercial
Bagger:
Exposure
estimates
for
bagging
activities
for
all
formulations
are
based
on
data
from
3
exposure
studies
(
MRID
Nos.
43080049,
42251902,
and
44904526).
The
studies
monitored
bagging
treated
seed
in
various
seed
treatment
facilities
and
encompassed
a
wide
range
of
bagging
equipment,
and
amount
of
seed
and
pesticides
handled.
The
number
of
replicates
ranged
from
1
to
20
per
study.
Two
of
the
studies
monitored
dermal
exposures
with
whole
body
dosimeters,
and
face,
neck
and
hand
rinses.
The
third
used
dermal
patches
and
hand
rinses
to
monitor
exposure.

Commercial
Sewer:
Exposure
estimates
for
sewing
activities
for
all
formulations
are
based
on
data
from
2
exposure
studies
(
MRID
#
430800­
49,
and449045­
26).
The
two
studies
monitored
sewing
various
bags
of
treated
seed
in
a
number
of
seed
treatment
facilities.
The
number
of
replicates
ranges
from
1
to
20
per
study.
Both
of
the
studies
monitored
dermal
exposures
with
whole
body
dosimeters,
and
face,
neck
and
hand
rinses.

Multiple
Commercial
Activities:
Exposure
estimates
for
multiple
activities
for
all
formulation
are
based
on
data
from
4
exposure
studies
(
MRID
#
s,
454427­
01,
422519­
02,
449045­
26
and
447315­
01).
These
studies
encompass
a
variety
of
seed
treatment
activity
and
a
wide
range
of
amount
of
seed
pesticides
handled.
The
four
studies
in
this
scenario
monitored
multiple
activities
for
various
seed
treatment
facilities.
The
number
of
replicates
ranges
from
3
to
45
per
study.
Three
of
the
five
studies
monitored
dermal
exposures
with
whole
body
dosimeter,
face
and
neck
and
hand
rinses.
The
methodology
in
the
other
studies
was
dermal
patches
and
hand
rinses.

TCMTB
Handler
Exposure
Scenarios
It
has
been
determined
that
exposure
to
pesticide
handlers
is
likely
during
the
occupational
use
of
TCMTB
in
a
variety
of
occupational
environments.
The
anticipated
use
patterns
and
current
labeling
indicate
several
occupational
exposure
scenarios
based
on
the
types
of
equipment
and
techniques
that
can
potentially
be
used
for
TCMTB
applications.
The
Page
16
of
23
quantitative
exposure/
risk
assessment
developed
for
occupational
handlers
is
based
on
the
following
scenarios.

Seed
treatment:

(
S­
1)
loading
and
applying
liquid
formulations
with
commercial
seed­
treatment
equipment,
(
S­
2)
commercial
sewer
stitching
bags
of
seed,
(
S­
3)
bagging
and
otherwise
handling
treated
seeds
with
commercial
equipment,
(
S­
4)
multiple
commercial
seed
treatment
activities,
(
S­
5)
on­
farm
loading/
applying
seed
treatment,
and
(
S­
6)
on­
farm
loading/
planting
previously
treated
seeds.

2.1.2
Noncancer
TCMTB
Handler
Exposure
and
Assessment
2.1.2.1
Noncancer
TCMTB
Handler
Exposure
and
Risk
Calculations
Daily
Exposure:
Daily
dermal
or
inhalation
handler
exposures
are
estimated
for
each
applicable
handler
task
with
the
application
rate,
the
area
treated
in
a
day,
and
the
applicable
dermal
or
inhalation
unit
exposure
using
the
following
formula:

Daily
Exposure
(
mg
ai/
day)
=
Unit
Exposure
(
mg
ai/
lb
ai
handled)
*
Application
Rate
(
lbs
ai/
area)
*
Daily
Area
Treated
(
area/
day)

Where:

Daily
Exposure
=
Amount
(
mg
ai/
day)
deposited
on
the
surface
of
the
skin
that
is
available
for
dermal
absorption
or
amount
inhaled
that
is
available
for
inhalation
absorption;
Unit
Exposure
=
Unit
exposure
value
(
mg
ai/
lb
ai
handled)
derived
from
August
1998
PHED
data,
from
ORETF
data;
Application
Rate
=
Normalized
application
rate
based
on
a
logical
unit
treatment,
such
as
acres,
square
feet,
or
gallons.
Maximum
values
are
generally
used
(
lb
ai/
cut
weight);
and
Daily
Area
Treated
=
Normalized
application
area
based
on
a
logical
unit
treatment
such
as
acres
(
A/
day).

Daily
Dose:
The
daily
dermal
or
inhalation
dose
is
calculated
by
normalizing
the
daily
exposure
by
body
weight
and
adjusting,
if
necessary,
with
an
appropriate
dermal
or
inhalation
absorption
factor.
For
all
exposure
scenarios
for
TCMTB,
an
average
adult
body
weight
of
70
kilograms
was
used,
since
the
toxicological
endpoint
of
concern
was
gender­
specific.
For
dermal
exposures,
no
dermal
absorption
factor
was
necessary,
since
the
toxicological
endpoint
is
from
a
dermal
study.
For
inhalation
exposures,
an
absorption
factor
of
100%
was
assumed.
Daily
dose
was
calculated
using
the
following
formula:
Average
Daily
Dose
(
mg/
kg/
day)
=
(
Daily
Exposure
(
mg
ai/
day)
*
(
Absorption
Factor
(%)
Page
17
of
23
Body
Weight
(
kg)

Where:

Average
Daily
Dose
=
Absorbed
dose
received
from
exposure
to
a
pesticide
in
a
given
scenario
(
mg
pesticide
active
ingredient/
kg
body
weight/
day);
Daily
Exposure
=
Amount
(
mg
ai/
day)
deposited
on
the
surface
of
the
skin
that
is
available
for
dermal
absorption
or
amount
inhaled
that
is
available
for
inhalation
absorption;
Absorption
Factor
=
A
measure
of
the
amount
of
chemical
that
crosses
a
biological
boundary
such
as
the
skin
or
lungs
(%
of
the
total
available
absorbed);
and
Body
Weight
=
Body
weight
determined
to
represent
the
population
of
interest
in
a
risk
assessment
(
kg).

Margins
of
Exposure:
Noncancer
dermal
and
inhalation
risks
for
each
applicable
handler
scenario
are
calculated
using
a
Margin
of
Exposure
(
MOE),
which
is
a
ratio
of
the
daily
dose
to
the
toxicological
endpoint
of
concern.
All
MOE
values
were
calculated
separately
for
dermal
and
inhalation
exposure
levels
using
the
formula
below:

MOE
=
(
NOAEL
(
mg/
kg/
day)
/
Average
Daily
Dose
(
mg/
kg/
day)

Where:

MOE
=
Margin
of
Exposure,
value
used
by
HED
to
represent
risk
or
how
close
a
chemical
exposure
is
to
being
a
concern
(
unitless);
ADD
=
Average
Daily
Dose
or
the
absorbed
dose
received
from
exposure
to
a
pesticide
in
a
given
scenario
(
mg
pesticide
active
ingredient/
kg
body
weight/
day);
and
NOAEL
=
Dose
level
in
a
toxicity
study,
where
no
observed
adverse
effects
(
NOAEL)
occurred
in
the
study
It
is
important
to
present
risk
estimates
for
each
route
of
exposure
(
i.
e.,
dermal
or
inhalation)
in
each
scenario
because
it
makes
determining
appropriate
risk
mitigation
measures
easier.
For
example,
if
overall
risks
are
driven
by
dermal
exposures
and
not
inhalation,
it
is
inadvisable
to
require
respirators
even
though
they
may
marginally
reduce
overall
risks.

A
total
MOE
was
calculated
for
TCMTB
because
common
toxicity
endpoints
were
used
to
calculate
dermal
and
inhalation
risks
for
each
exposure
duration.
The
dermal
and
inhalation
MOEs
were
combined
using
the
formula
below:

MOE
TOTAL
=
[
1/((
Dermal
MOE
)
+
(
1/
Inhalation
MOE))]

2.1.2.2
TCMTB
Noncancer
Risk
Summary
All
of
the
noncancer
risk
calculations
for
occupational
TCMTB
handlers
completed
in
this
assessment
are
included
in
the
appendices.
A
summary
of
the
short­
and
intermediate­
term
risks
for
each
exposure
scenario
are
presented
below
in
Tables
4
­
7.

Short­
and
Intermediate­
term
Dermal
and
Inhalation
Risks
Page
18
of
23
For
commercial
and
on­
farm
seed
treatment
scenarios,
all
dermal
and
inhalation
MOEs
met
or
exceeded
the
required
uncertainty
factor
of
100
at
some
level
of
mitigation.

Short­
and
Intermediate­
term
Total
Risks
For
commercial
and
on­
farm
seed
treatment
scenarios,
all
combined
dermal
and
inhalation
risks
met
or
exceed
the
required
uncertainty
factor
of
100
at
some
level
of
mitigation.

Table
4.
Estimated
Worker
Exposure
and
Risk
from
Commercial
Seed
Treatment
Short­
and
Intermediate­
term
MOEs
c
Baseline
Personal
Protective
Equipment
Engineering
Controls
Dermal
Inhalation
Crop
Exposure
Scenario
Application
Rate
(
lb
ai/
100
lb)
a
Amount
Handled
per
Day
(
lb
ai/
day)
b
Dermal
Inhalation
SL
w/
gloves
DL
w/
gloves
80%
R
90%
R
Dermal
Inhalation
Loader/
Applicator
ND
18000
410
520
88000
180000
1100
72000
Sewer
1500
26000
ND
ND
13000
260000
NF
NF
Bagger
1000
37000
ND
ND
190000
370000
NF
NF
Barley,
Oats
Rice,
Wheat
Seeds
Multiple
Activities
0.026
187
ND
3700
220
ND
19000
37000
NF
NF
Loader/
Applicator
ND
16000
370
470
79000
160000
980
65000
Sewer
1400
23000
ND
ND
120000
230000
NF
NF
Bagger
920
34000
ND
ND
170000
340000
NF
NF
Cotton
Seeds
Multiple
Activities
0.13
208
ND
3400
200
ND
17000
34000
NF
NF
Loader/
Applicator
ND
11000
260
330
56000
110000
690
46000
Sewer
960
17000
ND
ND
83000
170000
NF
NF
Bagger
650
24000
ND
ND
120000
240000
NF
NF
Safflower
Seeds
Multiple
Activities
0.041
294
ND
2400
140
ND
12000
24000
NF
NF
Loader/
Applicator
ND
91000
2100
2700
460000
910000
5600
370000
Sewer
7800
130000
ND
ND
670000
1300000
NF
NF
Bagger
5300
190000
ND
ND
970000
1900000
NF
NF
Sugar
Beet
Seeds
Multiple
Activities
0.041
36
ND
19000
1200
ND
97000
190000
NF
NF
ND
=
No
Data;
NF
=
Not
Feasible
a
Application
rates
are
the
maximum
application
rates
determined
from
EPA
registered
labels
for
TCMTB
b
Amount
handled
per
day
calculated
from
the
maximum
application
rate
and
the
lbs
of
seed
treated
or
planted/
day
and:
for
barley,
rice,
safflower,
and
wheat
seed
­
718000
lb/
day;
for
cotton
seed
 
160000
lb/
day;
and
sugar
beet
seed
 
88000
lb/
day.
c
Baseline
Dermal:
Long­
sleeve
shirt,
long
pants,
no
gloves.
Baseline
Inhalation:
no
respirator.
PPE
Dermal
SL
with
gloves:
Single
layer
plus
chemical­
resistant
gloves.
PPE
Dermal
DL
and
gloves:
Coveralls
worn
over
long­
sleeve
shirt
and
long
pants
plus
chemical­
resistant
gloves.
PPE
80%
R
inhalation:
assumes
a
dust/
mist
removing
filtering
face
piece
style
respirator
providing
an
80%
protection
factor.
PPE
90%
R
inhalation:
assumes
a
dust/
mist
removing
half­
face
style
respirator
providing
a
90%
protection
factor.
Eng
Controls
Dermal
and
Inhalation:
Closed
System.
Page
19
of
23
Table
5.
Combined
Estimated
Worker
Dermal
and
Inhalation
Risk
from
Commercial
Seed
Treatment
Combined
MOEs
c
Crop
Exposure
Scenario
App
Ratea
(
lb
ai/
lb)
Amount
Handled
per
Day
b
(
lb
ai/
day)
Baseline
SL,
G
+
NR
DL,
G
+
NR
SL
+
80%
R
SL,
G
+
80%
R
SL
+
90%
R
SL,
G+
90%
R
Eng
Control
Loader/
Applicator
ND
400
510
ND
410
ND
410
1000
Sewer
1400
ND
ND
1500
ND
1500
ND
NF
Bagger
970
ND
ND
990
ND
1000
ND
NF
Barley,
Oats,
Rice,
Wheat
Seeds
Multiple
Activities
0.026
187
ND
210
ND
ND
220
ND
220
NF
Loader/
Applicator
ND
360
450
ND
360
ND
360
920
Sewer
1300
ND
ND
1400
ND
1400
ND
NF
Bagger
900
ND
ND
910
ND
920
ND
NF
Cotton
Seeds
Multiple
Activities
0.13
208
ND
190
ND
ND
200
ND
200
NF
Loader/
Applicator
ND
250
320
ND
260
ND
260
650
Sewer
910
ND
ND
950
ND
950
ND
NF
Bagger
630
ND
ND
650
ND
650
ND
NF
Safflower
Seeds
Multiple
Activities
0.041
294
ND
130
ND
ND
140
ND
140
NF
Loader/
Applicator
ND
2100
2600
ND
2100
ND
2100
5300
Sewer
7400
ND
ND
7700
ND
7800
ND
NF
Bagger
5200
ND
ND
5300
ND
5300
ND
NF
Sugar
Beet
Seeds
Multiple
Activities
0.041
36
ND
1100
ND
ND
1100
ND
1100
NF
ND
=
No
Data;
NF
=
Not
Feasible
a
Application
rates
are
the
maximum
application
rates
determined
from
EPA
registered
labels
for
TCMTB
b
Amount
handled
per
day
calculated
from
the
maximum
application
rate
and
the
lbs
of
seed
treated
or
planted/
day
and:
for
barley,
rice,
safflower,
and
wheat
seed
­
718000
lb/
day;
for
cotton
seed
 
160000
lb/
day;
and
sugar
beet
seed
 
88000
lb/
day.

c
Baseline
=
No
gloves
and
no
respirator
SL,
G
=
Single
layer
w/
gloves
is
baseline
attire
plus
chemical­
resistant
gloves.

DL,
G
=
Double
layer
w/
gloves
is
coveralls
worn
over
long­
sleeve
shirt
and
long
pants,
plus
chemical­
resistant
gloves.

80%
R
=
80%
Respirator
is
dust/
mist
removing
filtering
face
piece
style
respirator
(
that
provides
an
80%
protection
factor).

90%
R
=
90%
Respirator
is
half­
face
dust/
mist
respirator
(
that
provides
a
90%
protection
factor).

Eng
Control
=
Engineering
control
is
closed
mixing/
loading
system,
enclosed
cab,
or
enclosed
cockpit.
Page
20
of
23
Table
6.
Estimated
Worker
Exposure
and
Risk
from
On­
farm
Seed
Treatment
Unit
Exposures
Short­
and
Intermediate­
term
MOEs
Baseline
Personal
Protective
Equipment
Engineering
Controls
Baseline
Personal
Protective
Equipment
Dermal
(
mg/
lb
ai)
Inhalation
(
ug/
lb
ai)
Dermal
Inhalation
Crop
Acres
treated/

day
App
Rate
(
lb
ai/

100
lb)
a
Amount
Handled
per
dayb
(
lb
ai/
day)
Dermalc
(
mg/
lb
ai)
Inhalationd
(

g/
lb
ai)
SL
w/
glovese
80%
Rf
90%
Rg
Dermalh
(
mg/
lb
ai)
Inhalationi
(
ug/
lb
ai)
Inhalation
SL
w/
gloves
80%
R
90%
R
LOADING/
APPLYING
LIQUID
SEED
TREATMENTS
Cotton
125
0.051
0.64
NDj
LOADING/
PLANTING
PREVIOUSLY
TREATED
SEEDS
Barley
35
0.026
0.64
360000
7700
1800000
3600000
Beet;
Sugar
80
0.041
0.26
1300000
27000
6300000
13000000
Cotton
200
0.13
4.68
70000
1500
350000
700000
Oats
200
0.026
6.66
49000
1100
250000
490000
Rice
200
0.026
7.80
42000
900
210000
420000
Safflower
80
0.041
3.28
100000
2100
500000
1000000
Wheat
200
0.026
7.80
ND
3.4
0.25
0.68
0.34
NF
NF
42000
900
210000
420000
ND
=
No
Data;
NF
=
Not
Feasible
a
Application
rates
are
the
maximum
application
rates
determined
from
EPA
registered
labels
for
TCMTB.

b
Amount
handled
per
day
calculated
from
the
acres
treated/
day
and
the
maximum
lb
of
seed
planted
per
acre.

c
Baseline
Dermal:
Long­
sleeve
shirt,
long
pants,
no
gloves.

d
Baseline
Inhalation:
no
respirator.

e
PPE
Dermal
SL
with
gloves:
Single
layer
plus
chemical­
resistant
gloves.

f
PPE
80%
R
inhalation:
assumes
a
dust/
mist
removing
filtering
face
piece
style
respirator
respirator
providing
an
80%
protection
factor.

g
PPE
90%
R
inhalation:
assumes
a
dust/
mist
removing
half­
face
style
respirator
providing
a
90%
protection
factor.

h
Eng
Controls
Dermal:
Closed
System.

i
Eng
Controls
Inhalation:
Closed
System.

j
On­
farm
seed
treatment
with
liquid
formulations
is
generally
done
with
automated
equipment,
essentially
miniature
versions
of
commercial
treaters.
Page
21
of
23
Table
7.
Combined
Estimated
Worker
Dermal
and
Inhalation
Risk
from
On­
farm
Seed
Treatment
Combined
MOEs
c
Crop
Acres
treated/
day
App
Ratea
(
lb
ai/
lb)
Amount
Handled
per
dayb
(
lb
ai/
day)
Baseline
SL,
G
+

NR
SL
+
80%
R
SL,
G
+
80%
R
SL
+
90%
R
SL,
G+
90%

R
Eng
Control
LOADING/
APPLYING
LIQUID
SEED
TREATMENTS
Cotton
125
0.051
0.64
NDd
LOADING/
PLANTING
PREVIOUSLY
TREATED
SEEDS
Barley
35
0.026
0.64
ND
7500
ND
7700
ND
7700
NF
Beet;
Sugar
80
0.041
0.26
ND
26000
ND
27000
ND
27000
NF
Cotton
200
0.13
4.68
ND
1500
ND
1500
ND
1500
NF
Oats
200
0.026
6.66
ND
1100
ND
1100
ND
1100
NF
Rice
200
0.026
7.80
ND
880
ND
900
ND
900
NF
Safflower
80
0.041
3.28
ND
2100
ND
2100
ND
2100
NF
Wheat
200
0.026
7.80
ND
880
ND
900
ND
900
NF
ND
=
No
Data;
NF
=
Not
Feasible
a
Application
rates
are
the
maximum
application
rates
determined
from
EPA
registered
labels
for
TCMTB
b
Amount
handled
per
day
calculated
from
the
acres
treated/
day
and
the
maximum
lb
of
seed
planted
per
acre.

c
Baseline
=
No
gloves
and
no
respirator
SL,
G
=
Single
layer
w/
gloves
is
baseline
attire
plus
chemical­
resistant
gloves.

DL,
G
=
Double
layer
w/
gloves
is
coveralls
worn
over
long­
sleeve
shirt
and
long
pants,
plus
chemical­
resistant
gloves.

80%
R
=
80%
Respirator
is
dust/
mist
removing
filtering
face
piece
style
respirator
(
that
provides
an
80%
protection
factor).

90%
R
=
90%
Respirator
is
half­
face
dust/
mist
respirator
(
that
provides
a
90%
protection
factor). 

Eng
Control
=
Engineering
control
is
closed
mixing/
loading
system,
enclosed
cab,
or
enclosed
cockpit.

d
On­
farm
seed
treatment
with
liquid
formulations
is
generally
done
with
automated
equipment,
essentially
miniature
versions
of
commercial
treaters.
Page
22
of
23
2.1.3
Cancer
TCMTB
Handler
Exposure
and
Risk
Assessment
The
Health
Effects
Division
Carcinogenicity
Peer
Review
Committee
(
CPRC)
met
on
June
28,
1995
to
discuss
and
evaluate
the
weight­
of­
the­
evidence
on
2­(
Thiocyanomethylthio)
benzothiazole
(
TCMTB)
with
particular
reference
to
its
carcinogenic
potential.
The
CPRC
concluded
that
TCMTB
should
be
classified
as
Group
C
­
possible
human
carcinogen
­
and
recommended
that
for
the
purpose
of
risk
characterization,
the
Reference
Dose
(
RfD)
approach
should
be
used
for
quantitation
of
human
risk.
This
was
based
on
statistically
significant
increases
in
tumors
in
both
sexes
of
the
Sprague­
Dawley
rat:
testicular
interstitial
cell
adenomas
in
males
and
thyroid
c­
cell
adenomas
in
females.

2.1.4
Summary
of
Risk
Concerns/
Data
Gaps
for
Occupational
Handlers
There
are
several
occupational
handler
scenarios
for
TCMTB
that
have
risks
associated
with
them
that
are
above
HED's
level
of
concern
for
noncancer
risk
assessments,
even
at
the
highest
level
of
risk
mitigation.
However,
there
are
also
some
occupational
handler
scenarios
for
TCMTB
that
have
data
gaps.

2.1.4.1
Summary
of
Risk
Concerns
The
short­
and
intermediate­
term
dermal
and
inhalation
handler
risk
assessment
for
TCMTB
indicates
risk
concerns
for
a
number
of
seed
treatment
scenarios,
even
with
maximum
risk
mitigation.
See
Section
2.1.3.2
for
a
detailed
summary.

2.1.4.2
Summary
of
Data
Gaps
One
data
gap
was
identified
for
TCMTB.
On­
farm
seed
treatment
with
liquid
formulations
is
generally
done
with
automated
equipment,
essentially
miniature
versions
of
commercial
treaters.
Currently,
HED
has
no
exposure
data
to
assess
this
particular
exposure
scenario.

2.1.5
Recommendations
For
Refining
Handler
Risk
Assessment
The
values
presented
in
the
Health
Effects
Division
Science
Advisory
Committee
on
Exposure
SOP
#
15:
Amount
of
Seed
Treated
or
Planted
per
Day
are
most
relevant
to
commercial
seed
treaters
and
growers
planting
treated
seed.
When
assessing
growers
who
do
on­
farm
seed
treatment,
the
values
may,
in
some
cases,
be
overestimates
or
underestimates,
depending
on
the
crop
type,
geographic
location
and
toxicity
endpoint.
Likewise,
because
of
limitations
on
farm
size/
crop
type
specific
to
the
pesticide
being
assessed,
the
volume
given
in
the
tables
may
not
be
appropriate.
These
are
cases
when
more
detailed
information
regarding
the
pesticide
application
rates,
geographical/
cultural
characteristics
of
the
crop
and
other
relevant
information
should
be
Page
23
of
23
considered
and
modifications
made
to
the
table
values
on
a
case­
by­
case
basis.
For
TCMTB,
no
chemical
specific
data
regarding
applications
to
seeds
is
currently
available.
In
order
to
refine
this
occupational
risk
assessment,
data
on
actual
use
patterns
including
rates,
timing,
and
seeds
treated
per
day
would
better
characterize
TCMTB
risks.