August
21,
2003
1
HFE­
7000
Exposure
During
Use
as
a
Cleaning
Solvent
HFE­
7000
has
previously
been
approved
for
use
as
a
refrigerant
and
as
an
aerosol
solvent.
For
the
aerosol
solvent
end­
use,
HFE­
7000
was
analyzed
for
two
uses:
1)
as
a
circuit
board
cleaner
sprayed
along
an
assembly
line
or
under
a
hood
in
a
well­
ventilated
factory
and
2)
as
a
mechanical
parts
cleaner
in
a
poorly
ventilated
shop.
For
each
of
the
scenarios,
the
largest
exposure
concentration
was
estimated
to
be
8.2
ppm,
which
was
significantly
lower
than
the
recommended
8­
hour
AEL
of
75
ppm.

Approval
is
being
sought
for
the
use
of
HFE­
7000
as
a
cleaning
solvent
in
precision
cleaning
and
electronics
cleaning
processes
in
addition
to
use
as
an
aerosol
solvent.
Cleaning
solvents
may
be
used
in
these
applications
using
vapor
degreasing
or
cold
cleaning
methods.
In
the
case
of
a
vapor
degreaser,
exposures
are
limited
by
likely
work
place
exposure
controls.
1
Because
aerosols
are
volatilized,
one
might
expect
higher
emissions
from
aerosol
exposure
than
from
exposure
to
solvent
used
in
industrial
cleaning
equipment.
However,
because
aerosol
use
results
in
intermittent
exposure
while
use
in
industrial
cleaning
equipment
results
in
continuous
exposure,
further
analysis
of
exposure
is
warranted
for
use
of
solvents
in
industrial
cleaning
equipment.

A
risk
screen
prepared
for
a
related
compound
(
HFE­
7100)
reports
actual
data
for
occupational
exposures
(
provided
by
the
submitter).
The
average
8­
hour
time
weighted
exposures
are
reported
in
Table
1
for
three
separate
scenarios
that
could
take
place
during
vapor
degreaser
use.
The
scenario
that
is
most
applicable
to
this
analysis
is
"
exposure
in
the
operator
zone."
The
occupational
exposure
level
(
i.
e.,
23
ppm)
for
this
scenario
is
below
the
AEL
for
HFE­
7000.

Table
1:
Occupational
Exposure
to
HFE­
7100
during
Solvent
Cleaning
Operations
Test
Scenario
Time
Period
of
Exposure
Occupational
Exposure
(
mg/
m3)
Occupational
Exposure
(
ppm)

Exposure
at
lip
of
Machine
8­
hour
time­
weighted
average
(
TWA)
3,384
331
Exposure
in
operator
zone
8­
hour
TWA
235
23
Exposure
during
a
spill
15­
minute
TWA
4,090
400
Note:
When
the
HFE­
7100
risk
screen
was
written,
HFE­
7100
had
an
occupational
exposure
limit
of
600
ppm
set
by
the
manufacturer.
Since
then,
the
AIHA
has
issued
a
WEEL
of
750
ppm
for
HFE­
7100.
The
value
reported
for
exposure
during
a
spill
is
not
an
8­
hour
TWA.
According
to
the
manufacturer,
the
highest
short­
term
(
acute)
exposure
to
HFE­
7100
is
less
than
400
ppm
during
routine
operations
or
in
the
case
of
a
moderate
spill.

1
For
cold
cleaning
applications,
exposures
may
be
higher
depending
on
the
type
of
work
place
environment
(
controlled
vs.
uncontrolled
emissions).
August
21,
2003
2
Because
the
vapor
pressure
of
HFE­
7100
is
less
than
half
that
of
HFE­
7000
(
200
mm
Hg
vs.
484
mm
Hg),
an
analog
method
presented
in
the
background
document
should
be
adopted
to
more
precisely
determine
the
occupational
exposure
of
HFE­
7000.
For
the
"
exposure
in
the
operator
zone",
the
occupational
exposure
of
HFE­
7000
can
be
estimated
at
70
ppm
using
the
equation
below
and
the
HFE­
7100
exposure
data:

C
(
substitute)
=
C
(
analog)
*
P
(
substitute)
P
(
analog)

Where:
C
(
substitute)
=
estimated
concentration
for
the
substitute,
in
mg/
m3
C
(
analog)
=
actual
exposure
concentration
for
the
analog,
in
mg/
m3
P
(
substitute)
=
vapor
pressure
of
substitute,
in
mm
Hg
P
(
analog)
=
vapor
pressure
of
analog,
in
mm
Hg
Using
this
equation,
the
following
exposures
are
projected:

Table
2:
Projected
Occupational
Exposure
to
HFE­
7000
during
Solvent
Cleaning
Operations
Test
Scenario
Time
Period
of
Exposure
Occupational
Exposure
(
mg/
m3)
Occupational
Exposure
(
ppm)

Exposure
at
lip
of
Machine
8­
hour
time­
weighted
average
(
TWA)
8,188
1,001
Exposure
in
operator
zone
8­
hour
TWA
573
70
Exposure
during
a
spill
15­
minute
TWA
9,898
1,210
Note:
The
exposure
estimated
for
a
spill
represents
a
short­
term
acute
exposure.

Exposure
in
the
operator
zone
is
the
most
common
scenario
and
the
scenario
that
best
represents
typical
long­
term
exposure
in
the
workplace.
For
exposure
in
the
operator
zone,
the
occupational
exposure
level
is
below
HFE­
7000'
s
AEL.
However,
because
there
is
a
safety
margin
of
roughly
7
percent
between
the
occupational
exposure
in
the
operator
zone
and
HFE­
7000'
s
AEL,
precautions
should
be
taken
to
reduce
the
occupational
exposure.
To
ensure
that
occupational
exposure
does
not
exceed
the
AEL
of
75
ppm,
the
following
exposure
controls
can
be
employed.
2
1)
Install
proper
ventilation;
2)
Always
use
covers
on
cold­
cleaning
and
vapor
degreasing
equipment
when
not
in
use;
3)
Increase
freeboard
height
and/
or
freeboard
condensers
on
the
vapor
degreaser
for
maximum
condensation;
4)
Follow
industrial
hygiene
practices
and
train
workers
to
follow
practices;
5)
Place
signs
in
the
work
place
warning
workers
of
the
symptoms
that
may
incur
from
over­
exposure
to
HFE­
7000;
6)
Provide
training
in
the
proper
use
of
cold
cleaning
and
vapor
degreasing
equipment.

2
It
is
particularly
important
that
these
measures
be
in
place
for
cold
cleaning
applications.
Use
of
HFE­
7000
for
hand
wiping
should
be
discouraged.
August
21,
2003
3
Exposure
at
the
lip
of
the
machine
is
a
conservative
scenario
for
short­
term
exposure
that
would
exceed
exposures
normally
experienced
by
a
worker
over
the
course
of
a
workday.
Workers
would
move
to
the
lip
of
a
machine
while
adding
or
removing
workloads
in
industrial
cleaning
equipment,
but
typically
would
not
remain
at
the
lip
of
the
machine
all
day.
Thus,
the
exposures
resulting
from
this
scenario
are
more
reasonably
compared
to
an
emergency
guidance
level
(
EGL)
3
than
to
a
STEL
or
an
8­
hour
AEL.
These
exposures
are
expected
to
be
very
high
and
very
short
in
duration,
and
thus
are
not
applicable
to
an
AEL
or
a
15­
minute
STEL.

The
EGL
should
be
informed
by
acute
toxicity
of
the
compound,
identified
in
animal
tests.
Although
no
acute
studies
with
this
compound
were
identified,
a
sub­
acute
toxicity
assay
performed
with
HFE­
7000
did
not
reveal
any
clinical
effects
or
mortality
at
concentrations
as
high
as
30,000
ppm
following
20
days
of
exposure
(
Arts
1999).
Therefore,
the
exposure
concentration
in
rats
required
to
induce
acute
effects
exceeds
this
concentration.
Thus,
the
recommended
EGL
for
HFE­
7000
is
3,000
ppm
based
on
one­
tenth
of
the
acute
toxicity
NOAEL
of
30,000
ppm.
This
value
is
a
conservative
exposure
limit,
as
it
is
essentially
based
on
a
true
NOAEL
for
rodents
with
an
uncertainty
factor
of
10
applied
for
extrapolation
to
humans.
As
no
clinical
effects
in
rodents
were
observed
even
after
20
days
of
exposure
to
the
compound
at
30,000
ppm,
it
is
unlikely
that
a
one­
time
exposure
to
3,000
ppm
would
induce
acute
toxicity
in
humans.
The
calculation
of
this
EGL
is
similar
to
calculations
used
to
develop
other
exposure
limits
such
as
AELs.
A
calculation
to
account
for
period
of
exposure
is
unnecessary
because
the
value
is
for
immediate
effects
that
do
not
necessarily
require
a
particular
period
of
time
to
develop.
No
additional
application
of
uncertainty
factors
is
required
because
the
value
is
developed
from
a
true
(
and
likely
conservative)
NOAEL.

Additionally,
for
the
worst­
case
scenario,
a
spill
situation,
the
exposure
should
be
compared
to
an
EGL
instead
of
a
STEL
because
spills
represent
very
infrequent
events
that
involve
much
higher
exposure
concentrations
than
those
situations
that
are
typically
compared
to
a
STEL.
Furthermore,
STELs
can
be
exceeded
within
a
given
day,
as
long
as
the
daily
average
concentration
does
not
exceed
the
overall
exposure
limit
(
AEL).
If
at
all
possible,
the
EGL
should
not
be
exceeded.
Spills
also
should
be
cleaned
up
as
quickly
as
is
practical.
Hence,
using
the
analog
method,
concentrations
of
HFE­
7000
experienced
during
a
spill
would
be
1,210
ppm,
well
below
the
EGL
of
3,000
ppm.

Further,
because
other
cleaning
solvents
have
lower
exposure
limits
in
place
(
e.
g.,
enforceable
OSHA
PELs
for
chlorinated
solvents
set
at
50
ppm
or
25
ppm)
that
are
consistently
met
in
the
workplace,
it
is
believed
that
a
25
ppm
work
place
level
can
be
met
for
other
solvent
cleaners
(
in
this
case,
HFE­
7000)
given
the
use
of
proper
controls,
as
described
above
(
EPA
1994).
This
further
supports
the
conclusion
that
exposures
can
be
maintained
below
the
AEL
for
HFE­
7000,
particularly
if
proper
industrial
hygiene
is
practiced
in
the
work
place.

3
The
EGL
is
based
on
0.1
times
the
acute
NOAEL.
August
21,
2003
4
References:

Arts
JH,
Kuper
CF,
and
Muijser
H.
(
1999).
A
sub­
acute
(
30
day)
inhalation
toxicity
study,
including
a
recovery
study,
with
T­
6903
in
rats.
TNO
Report
No.
V99.566.
TNO
Nutrition
and
Food
Research
Institute,
The
Netherlands.

EPA
1994.
Significant
New
Alternatives
Policy
Technical
Background
Document:
Risk
Screen
on
the
Use
of
Substitutes
for
Class
I
Ozone­
depleting
Substances:
Solvent
Cleaning.
Stratospheric
Protection
Division.
March
1994.

29
CFR
1910.1000,
OSHA
standards
for
exposure
to
air
contaminants.
