September
10,
2003
1
RISK
SCREEN
ON
THE
USE
OF
SUBSTITUTES
FOR
OZONE­
DEPLETING
SUBSTANCES
REFRIGERATION
AND
AIR
CONDITIONING
End­
Use:
Proposed
Replacement
for
R­
13B1
in
Very
Low
Temperature
Refrigeration
Refrigerant:
ISCEON
 
89
This
risk
screen
contains
no
Clean
Air
Act
(
CAA)
Confidential
Business
Information
(
CBI)
and,
therefore,
can
be
disclosed
to
the
public.

1.
INTRODUCTION
Stratospheric
ozone­
depleting
substances
(
ODS)
are
being
phased
out
of
production
in
response
to
a
series
of
diplomatic
and
legislative
efforts,
including
the
Montreal
Protocol
and
the
Clean
Air
Act
Amendments
of
1990
(
CAAA).
The
U.
S.
Environmental
Protection
Agency
(
EPA),
as
authorized
by
Section
612
of
the
CAAA,
has
developed
a
program
to
evaluate
the
human
health
and
environmental
risks
posed
by
alternatives
to
ODS.
The
main
purpose
of
EPA's
program,
called
the
Significant
New
Alternatives
Policy
(
SNAP)
program,
is
to
identify
acceptable
and
unacceptable
substitutes
for
ODS
in
specific
end­
uses.

EPA's
decision
on
the
acceptability
of
a
substitute
is
based
largely
on
the
findings
of
a
screening
assessment
of
potential
human
health
and
environmental
risks
posed
by
the
substitute
in
specific
applications.
EPA
has
already
screened
a
large
number
of
substitutes
in
many
enduses
within
all
of
the
major
ODS­
using
sectors,
including
refrigeration
and
air
conditioning;
solvent
cleaning;
foam­
blowing;
aerosols;
fire
extinguishing;
adhesives,
coatings,
and
inks;
and
sterilization.
The
results
of
these
risk
screens
are
presented
in
a
series
of
background
documents
that
are
available
in
this
docket.

The
purpose
of
this
report
is
to
supplement
EPA's
background
document
on
the
refrigeration
and
air
conditioning
sector1
(
hereinafter
referred
to
as
the
Background
Document)
by
adding
to
the
list
of
potential
substitutes
for
specific
end­
uses
of
R­
13B1
in
this
sector.
The
reader
is
referred
to
this
reference
for
an
additional
discussion
of
different
methodologies
used
to
conduct
risk
screens.
The
specific
proposed
substitute
blend
examined
in
this
report
is
ISCEON
®
89
which
may
be
used
in
the
following
applications:
environmental
test
chambers,
low
temperature
freeze
dryers,
low
temperature
storage,
and
process
control.
The
potential
risks
associated
with
use
of
the
constituents
of
this
blend
in
the
refrigeration
and
air
conditioning
end
use
have
been
examined
at
length
in
the
Background
Document.

1
EPA
1994.
Significant
New
Alternatives
Policy
Technical
Background
Document:
Risk
Screen
on
the
Use
of
Substitutes
for
Class
I
Ozone­
depleting
Substances:
Refrigeration
and
Air
Conditioning.
Stratospheric
Protection
Division.
March,
1994.
September
10,
2003
2
Section
2
of
this
report
summarizes
the
results
of
the
risk
screen
for
the
proposed
substitute
blend
listed
in
Table
1.
The
remainder
of
the
report
is
organized
similarly
to
the
Background
Document:
Section
3
presents
the
toxicity
values
used
for
the
risk
screen,
Section
4
presents
the
results
of
the
atmospheric
assessment,
Sections
5
and
6
discuss
occupational
and
general
population
exposures,
respectively.
Section
7
addresses
flammability
concerns,
and
Section
8
discusses
potential
increases
in
atmospheric
releases
of
volatile
organic
compounds
(
VOCs).

TABLE
1.
PROPOSED
SUBSTITUTE
BLEND
Refrigerant
Blend
(
Trade
Name)
Constituents
Percent
by
Weight
CAS
Number
HFC­
125
(
also
known
as
pentafluorethane)
86
354­
33­
6
R­
218
(
also
known
as
octafluoropropane)
9
76­
19­
7
Isceon
 
89
propane
5
74­
98­
6
2.
SUMMARY
OF
RESULTS
Isceon
 
89
is
recommended
for
SNAP
approval
for
all
the
proposed
end
uses.
EPA's
risk
screen
indicates
that
the
use
of
the
proposed
substitute
will
be
less
harmful
to
the
atmosphere
than
the
continued
use
of
R­
13B1
blends.
No
significant
risks
to
workers
are
estimated
based
on
occupational
exposure
modeling.
Additionally,
general
population
exposure
to
the
substitute
is
expected
to
be
below
levels
of
concern
for
noncancer
risks.
For
applications
of
this
and
all
other
refrigerants,
EPA
recommends
that
American
Society
of
Heating,
Refrigerating
and
Air­
Conditioning
Engineers
(
ASHRAE)
Standards
15
and
34
be
followed.

3.
TOXICITY
REFERENCE
VALUES
FOR
SUBSTITUTES
To
assess
potential
health
risks
from
exposure
to
this
substitute
for
ODS
in
the
refrigeration
and
air­
conditioning
sector,
EPA
identified
the
relevant
toxicity
threshold
values,
including
available
occupational
exposure
limits
(
OELs),
for
comparison
to
modeled
exposure
concentrations
for
different
scenarios.
For
the
occupational
exposure
analysis
provided
in
this
risk
screen,
potential
risks
from
chronic
worker
exposure
were
evaluated
by
comparing
exposure
concentrations
to
values
derived
by
EPA,
namely
acceptable
exposure
levels
(
AELs).
Potential
risks
from
short­
term
occupational
exposures
were
also
evaluated
through
comparison
with
values
derived
by
EPA,
namely
short­
term
exposure
levels
(
STELs).
Reference
concentrations
September
10,
2003
3
(
RfCs)
were
used
to
assess
risks
to
the
general
population
from
exposure
to
ambient
air
releases.
The
OELs
and
RfCs
used
for
this
assessment
are
shown
in
Table
2.
EPA's
approach
for
identifying
or
developing
these
values
is
discussed
in
Chapter
3
of
the
Background
Document.

TABLE
2.
TOXICITY
THRESHOLD
VALUES
AEL
(
Long­
term
Exposure)
STEL
(
Short­
term
Exposure)
Cardiotoxic
LOAEL
Cardiotoxic
NOAEL
Reference
Concentration
(
RfC)
Chemical
ppm
ppm
ppm
ppm
ppm
mg/
m3
HFC­
125
1,000a
4,000b
100,000c
75,000c
2
i
10
i
R­
218
1,000d
3,000e
400,000f
300,000f
0.5
i
4.5
i
propane
1,000g
7,500h
100,000
i
50,000
i
0.5
i
0.9
i
Source:
EPA
1993,
EPA
1994,
EPA
1995,
PAFT
1996,
SNAP
submission
ISCEON
®
98,
2003.
a
WEEL
(
8­
hour
time­
weighted
average)
established
by
AIHA
(
1999).
b
TLV­
STEL
(
Threshold
Limit
Value
Short­
Term
Exposure
Limit),
a
workplace
standard
sometimes
used
as
a
level
of
concern
for
emergency
response.
A
chemical's
TLV­
STEL
is
the
maximum
time­
weighted
average
concentration
of
that
chemical
in
the
air
to
which
workers
may
be
exposed
for
up
to
15
minutes.
c
Calm
1996
d
Rhône­
Poulenc
Chemical
Ltd.
internal
occupational
exposure
limit
(
1996)
as
stated
in
the
SNAP
submission
for
ISCEON
®
89
(
2003).
Also,
1000
ppm
AEL
estimated
in
Background
document
(
EPA
1994)
by
analogy
to
propane.
e
STEL
was
estimated
as
three
times
the
AEL;
this
method
of
estimating
a
short­
term
exposure
limit
is
commonly
done
by
ACGIH.
f
Study
summerized
in
the
SNAP
submission
for
ISCEON
®
89
(
2003).
g
PEL
(
8­
hour
time­
weighted
average)
established
by
OSHA
(
1998)
(
29
CFR
1910.1000).
h
Excursion
limit
Recommendation
for
30
minute
exposure
which
can
exceed
3
times
the
8­
hour
TLV­
TWA
(
2500
ppm)
established
by
ACGIH
(
2002).
i
EPA
1994
ACGIH
=
American
Conference
of
Governmental
Industrial
Hygienists;
AIHA
=
American
Industrial
Hygiene
Association;
STEL
=
Short
Term
Exposure
Level;
LOAEL
=
Lowest
Observed
Adverse
Effect
Level;
NOAEL
=
No
Observed
Adverse
Effect
Level;
WEEL=
Workplace
Environmental
Exposure
Level;
AEL
=
Acceptable
Exposure
Level;
NA=
Not
Available
4.
ATMOSPHERIC
MODELING
This
section
presents
an
assessment
of
the
potential
risks
to
atmospheric
integrity
posed
by
the
use
of
ISCEON
®
89
in
the
refrigeration
and
air­
conditioning
sector.
The
ODP,
GWP,
and
ALT
of
the
proposed
substitute
are
presented
in
Table
3.

The
environmental
impacts
resulting
from
use
of
ISCEON
®
89
are
generally
in
the
range
of
those
predicted
for
other
substitutes
examined
in
the
Background
Document.
EPA
believes
that
the
substitute
is
substantially
less
harmful
to
the
ozone
layer
than
the
continued
use
of
R­
13B1.
The
100­
Year
Weighted
GWP
of
ISCEON
®
89
is
approximately
3,554
relative
to
CO2.
September
10,
2003
4
However,
ISCEON
®
89
is
not
believed
to
pose
a
substantial
threat
to
the
environment
because
its
use
is
restricted
to
low­
temperature
refrigeration
used
by
medical
and
research
facilities
so
the
production
and
release
of
ISCEON
®
89
is
expected
to
be
minimal.
Additionally,
low
temperature
refrigerators
may
use
more
damaging
alternatives
or
higher
concentrations
of
R­
218.
ISCEON
®
89
has
a
lower
GWP
than
HFC­
23,
another
alternative
substitute
for
R­
13B1
in
low­
temperature
refrigeration,
with
a
100­
Year
GWP
of
12,000
(
IPCC
2000).

TABLE
3.
ODP,
GWP,
AND
ALT
FOR
PROPOSED
REFRIGERATION
AND
AIR
CONDITIONING
SUBSTITUTES
SUBSTITUTE
ODP
100­
Year
GWP
(
relative
to
CO2)
100­
Year
Weighted
GWP
(
relative
to
CO2)
ALT
(
years)

HFC­
125
0
3,400a
2,924
32.6a
R­
218
0
7,000b
630
2,600b
propane
0
­­­
­­­­
<
0.5c
a
Source:
IPCC
(
2000).
b
Source:
Houghton
(
1995).
c
ALT
of
propane
is
5­
21
days
(
Wuebbles
2003).
­­­­
Not
applicable
5.
OCCUPATIONAL
EXPOSURE
AND
RISK
SCREENING
ANALYSIS
Occupational
exposure
modeling
was
performed
for
the
components
of
the
proposed
blend
to
ensure
that
use
of
the
blend
does
not
pose
an
unacceptable
risk
to
workers.
The
highest
8­
hour
estimated
exposure
for
HFC­
125
in
all
proposed
end
uses
for
both
manufacture
and
disposal
was
339
ppm.
For
R­
218,
the
highest
8­
hour
estimated
exposure
for
all
proposed
end
uses
was
93
ppm,
and
for
propane,
the
highest
8­
hour
estimated
exposure
was
54
ppm.
All
of
the
8­
hour
exposure
values
fall
well
below
1,000
ppm,
the
AEL
of
all
three
chemicals,
and
therefore
pose
no
health
risks
in
occupational
settings.

The
highest
15­
minute
estimated
exposure
for
HFC­
125
in
all
proposed
end
uses
for
both
manufacture
and
disposal
was
1006
ppm.
For
R­
218,
the
highest
15­
minute
estimated
exposure
was
275
ppm,
and,
the
highest
15­
minute
estimated
exposure
for
propane
was
318
ppm.
The
15­
minute
exposure
values
for
the
three
substitute
components
are
all
well
below
the
lowest
STEL
of
3000
ppm
for
both
manufacture
and
disposal.
(
See
Attachment
1
for
discussion
of
R­
218
STEL).
September
10,
2003
5
The
analysis
concluded
that
occupational
exposure
to
any
of
the
constituents
in
the
ISCEON
®
89
blend,
HFC­
125,
R­
218,
and
propane,
is
not
expected
to
pose
unacceptable
risks
to
workers.

6.
GENERAL
POPULATION
EXPOSURE
This
section
screens
potential
risks
to
the
general
population
from
exposure
to
ambient
air
releases
of
the
substitutes
examined
in
this
report.
The
methodology
used
for
refrigerant
screening
was
identical
to
the
one
used
in
the
general
population
exposure
analysis
described
in
Chapter
7
of
the
Refrigeration
and
Air
Conditioning
Background
Document.
A
thorough
review
of
HCFC
and
HFC
substitutes
by
end
use
is
provided
including
specific
data
for
HFC­
125,
R­
218,
and
propane
(
EPA
1994).
Table
4
shows
that
all
three
substitutes
had
exposure
concentrations
at
orders
of
magnitude
below
the
reference
concentrations,
even
using
conservative
screening
assumptions.
Thus,
releases
of
HFC­
125,
R­
218,
and
propane
(
as
shown
in
Table
4)
during
manufacture,
end
use,
and
disposal,
are
not
expected
to
pose
a
health
risk
to
the
general
population.

TABLE
4.
RATIO
OF
HIGHEST
EXPOSURE
CONCENTRATION
TO
RfC
Chemical
Highest
Exposure
Concentration/
RfC
Ratio
HFC­
125
0.049
R­
218
0.071
Propane
0.14
Source:
EPA
1994.

7.
FLAMMABILITY
ANALYSIS
It
is
important
to
consider
the
flammability
of
substances
when
investigating
their
acceptability
for
use
as
refrigerants
since
substitutes
that
are
flammable
could
pose
safety
concerns
to
workers.
As
reported
in
the
submission,
ISCEON
®
89
has
been
tested
by
Chillworth
Research
Centre
(
Southampton,
England)
and
was
considered
nonflammable,
and
thus
poses
no
danger
of
flame
propagation.
A
Worst
Case
Fractionation
Composition
Flammability
Test
under
the
guidance
of
Underwriters
Laboratories
Inc.
Standard
2182
at
25
º
C
demonstrated
a
small
blue
flame
that
was
non­
propagating
in
11­
17%
(
v/
v)
samples.

8.
VOLATILE
ORGANIC
COMPOUND
(
VOC)
ANALYSIS
August
1,
2003
6
HFC­
125
and
R­
218
have
been
exempted
from
listing
as
VOCs
under
CAA
regulations
(
40
CFR
§
51.000).
With
respect
to
propane,
the
analysis
presented
in
the
Background
Document
has
shown
that
potential
emissions
of
VOCs
from
all
substitutes
for
all
end
uses
in
the
refrigeration
and
air
conditioning
sector
are
likely
to
be
insignificant
relative
to
VOCs
from
all
other
sources
(
i.
e.,
both
anthropogenic
and
biogenic).
Propane
has
not
been
exempted
as
a
VOC
under
the
CAA,
however,
emissions
are
controlled
through
existing
regulations
and
industry
practices.
September
10,
2003
7
REFERENCES
American
Industrial
Hygiene
Association.
The
AIHA
1999
Emergency
Response
Planning
Guidelines
and
Workplace
Environmental
Exposure
Level
Guides
Handbook.
American
Industrial
Hygiene
Association.
Fairfax,
VA
1999.

Calm,
James
M.
1996.
The
Toxicity
of
Refrigerants.
Presented
at
the
International
Refrigeration
Conference,
Purdue
University,
July
1996.

EPA.
1994.
"
SNAP
Technical
Background
Document:
Risk
Screen
on
the
Use
of
Substitutes
for
Class
I
Ozone­
depleting
Substances:
Refrigeration
and
Air
Conditioning."
Stratospheric
Protection
Division.
March,
1994.

EPA.
1995.
IRIS
website.
http://
www.
epa.
gov/
iris/
subst/
0656.
htm.

Houghton,
J.
T.
et
al.
(
eds),
Climate
Change
1995;
The
Science
of
Climate
Change
(
New
York,
NY:
Cambridge
University
Press,
1996).
Contribution
of
Working
Group
I
to
the
Second
Assessment
Report
of
the
Intergovernmental
Panel
on
Climate
Change.

IPCC
(
Intergovernmental
Panel
on
Climate
Change),
2000:
Emissions
Scenarios.
N.
Nakicenovic,
J.
Alcamo,
G.
Davis,
B.
de
Vries,
J.
Fenhann,
S.
Gaffin,
K.
Gregory,
A.
Grübler,
T.
Y.
Jong,
T.
Kram,
E.
Lebre
La
Rovere,
L.
Michaelis,
S.
Mori,
T.
Morita,
W.
Pepper,
H.
Pitcher,
L.
Price,
K.
Riahi,
A.
Roehrl,
H­
H.
Rogner,
A.
Sankovski,
M.
Schlesinger,
P.
Shukla,
S.
Smith,
R.
Swart,
S.
van
Rooijen,
N.
Victor,
and
D.
Zhou
(
eds.),
Special
Report
of
WGIII
of
the
IPCC,
Cambridge
University
Press,
Cambridge,
UK,
ISBN
0­
521­
80493­
0.

ISCEON
®
89,
2003.
Application
to
SNAP
for
approval
of
ISCEON
®
89
submitted
by
Fluorinated
Consumer
Products.

Programme
for
Alternative
Fluorocarbon
Toxicity
Testing.
(
PAFT).
1996.
Website
http://
www.
afeas.
org/
paft/

Wuebbles
2003.
Personal
communication
with
Don
Wuebbles.
E­
mail.
July
21,
2003.
